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TM4C1231H6PMIR

TM4C1231H6PMIR

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    LQFP-64

  • 描述:

    IC MCU 32BIT 256KB FLASH 64LQFP

  • 数据手册
  • 价格&库存
TM4C1231H6PMIR 数据手册
TE X AS I NS TRUM E NTS - P RO DUCTION D ATA Tiva™ TM4C1231H6PM Microcontroller D ATA SHE E T D S -T M 4C 1231 H6 P M - 1 5 8 4 2 . 2 7 4 1 S P M S 339E C o p yri g h t © 2 0 07-2014 Te xa s In stru me n ts In co rporated Copyright Copyright © 2007-2014 Texas Instruments Incorporated. Tiva and TivaWare are trademarks of Texas Instruments Incorporated. ARM and Thumb are registered trademarks and Cortex is a trademark of ARM Limited. All other trademarks are the property of others. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Texas Instruments Incorporated 108 Wild Basin, Suite 350 Austin, TX 78746 http://www.ti.com/tm4c http://www-k.ext.ti.com/sc/technical-support/product-information-centers.htm 2 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table of Contents Revision History ............................................................................................................................. 32 About This Document .................................................................................................................... 36 Audience .............................................................................................................................................. About This Manual ................................................................................................................................ Related Documents ............................................................................................................................... Documentation Conventions .................................................................................................................. 36 36 36 37 1 Architectural Overview .......................................................................................... 39 1.1 1.2 1.3 1.3.1 1.3.2 1.3.3 1.3.4 1.3.5 1.3.6 1.3.7 1.4 1.5 1.6 Tiva™ C Series Overview .............................................................................................. 39 TM4C1231H6PM Microcontroller Overview ..................................................................... 40 TM4C1231H6PM Microcontroller Features ..................................................................... 42 ARM Cortex-M4F Processor Core .................................................................................. 42 On-Chip Memory ........................................................................................................... 44 Serial Communications Peripherals ................................................................................ 46 System Integration ........................................................................................................ 49 Analog .......................................................................................................................... 55 JTAG and ARM Serial Wire Debug ................................................................................ 57 Packaging and Temperature .......................................................................................... 58 TM4C1231H6PM Microcontroller Hardware Details ......................................................... 58 Kits .............................................................................................................................. 58 Support Information ....................................................................................................... 58 2 The Cortex-M4F Processor ................................................................................... 59 2.1 2.2 2.2.1 2.2.2 2.2.3 2.2.4 2.3 2.3.1 2.3.2 2.3.3 2.3.4 2.3.5 2.3.6 2.4 2.4.1 2.4.2 2.4.3 2.4.4 2.4.5 2.4.6 2.4.7 2.5 2.5.1 2.5.2 Block Diagram .............................................................................................................. 60 Overview ...................................................................................................................... 61 System-Level Interface .................................................................................................. 61 Integrated Configurable Debug ...................................................................................... 61 Trace Port Interface Unit (TPIU) ..................................................................................... 62 Cortex-M4F System Component Details ......................................................................... 62 Programming Model ...................................................................................................... 63 Processor Mode and Privilege Levels for Software Execution ........................................... 63 Stacks .......................................................................................................................... 64 Register Map ................................................................................................................ 64 Register Descriptions .................................................................................................... 66 Exceptions and Interrupts .............................................................................................. 82 Data Types ................................................................................................................... 82 Memory Model .............................................................................................................. 82 Memory Regions, Types and Attributes ........................................................................... 84 Memory System Ordering of Memory Accesses .............................................................. 85 Behavior of Memory Accesses ....................................................................................... 85 Software Ordering of Memory Accesses ......................................................................... 86 Bit-Banding ................................................................................................................... 87 Data Storage ................................................................................................................ 89 Synchronization Primitives ............................................................................................. 90 Exception Model ........................................................................................................... 91 Exception States ........................................................................................................... 92 Exception Types ............................................................................................................ 92 June 12, 2014 3 Texas Instruments-Production Data Table of Contents 2.5.3 2.5.4 2.5.5 2.5.6 2.5.7 2.6 2.6.1 2.6.2 2.6.3 2.6.4 2.7 2.7.1 2.7.2 2.8 Exception Handlers ....................................................................................................... 96 Vector Table .................................................................................................................. 96 Exception Priorities ....................................................................................................... 97 Interrupt Priority Grouping .............................................................................................. 98 Exception Entry and Return ........................................................................................... 98 Fault Handling ............................................................................................................. 101 Fault Types ................................................................................................................. 102 Fault Escalation and Hard Faults .................................................................................. 102 Fault Status Registers and Fault Address Registers ...................................................... 103 Lockup ....................................................................................................................... 103 Power Management .................................................................................................... 104 Entering Sleep Modes ................................................................................................. 104 Wake Up from Sleep Mode .......................................................................................... 104 Instruction Set Summary .............................................................................................. 105 3 Cortex-M4 Peripherals ......................................................................................... 112 3.1 3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.2 3.3 3.4 3.5 3.6 3.7 Functional Description ................................................................................................. 112 System Timer (SysTick) ............................................................................................... 113 Nested Vectored Interrupt Controller (NVIC) .................................................................. 114 System Control Block (SCB) ........................................................................................ 115 Memory Protection Unit (MPU) ..................................................................................... 115 Floating-Point Unit (FPU) ............................................................................................. 120 Register Map .............................................................................................................. 124 System Timer (SysTick) Register Descriptions .............................................................. 127 NVIC Register Descriptions .......................................................................................... 131 System Control Block (SCB) Register Descriptions ........................................................ 146 Memory Protection Unit (MPU) Register Descriptions .................................................... 175 Floating-Point Unit (FPU) Register Descriptions ............................................................ 184 4 JTAG Interface ...................................................................................................... 190 4.1 4.2 4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.4 4.5 4.5.1 4.5.2 Block Diagram ............................................................................................................ Signal Description ....................................................................................................... Functional Description ................................................................................................. JTAG Interface Pins ..................................................................................................... JTAG TAP Controller ................................................................................................... Shift Registers ............................................................................................................ Operational Considerations .......................................................................................... Initialization and Configuration ..................................................................................... Register Descriptions .................................................................................................. Instruction Register (IR) ............................................................................................... Data Registers ............................................................................................................ 191 191 192 192 194 194 195 197 198 198 200 5 System Control ..................................................................................................... 202 5.1 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 5.2.6 Signal Description ....................................................................................................... Functional Description ................................................................................................. Device Identification .................................................................................................... Reset Control .............................................................................................................. Non-Maskable Interrupt ............................................................................................... Power Control ............................................................................................................. Clock Control .............................................................................................................. System Control ........................................................................................................... 4 202 202 202 203 208 208 209 215 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 5.3 5.4 5.5 5.6 Initialization and Configuration ..................................................................................... Register Map .............................................................................................................. System Control Register Descriptions ........................................................................... System Control Legacy Register Descriptions ............................................................... 220 220 225 393 6 System Exception Module ................................................................................... 450 6.1 6.2 6.3 Functional Description ................................................................................................. 450 Register Map .............................................................................................................. 450 Register Descriptions .................................................................................................. 450 7 Hibernation Module .............................................................................................. 458 7.1 7.2 7.3 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 7.3.6 7.3.7 7.3.8 7.3.9 7.3.10 7.3.11 7.3.12 7.4 7.4.1 7.4.2 7.4.3 7.4.4 7.4.5 7.5 7.6 Block Diagram ............................................................................................................ Signal Description ....................................................................................................... Functional Description ................................................................................................. Register Access Timing ............................................................................................... Hibernation Clock Source ............................................................................................ System Implementation ............................................................................................... Battery Management ................................................................................................... Real-Time Clock .......................................................................................................... Battery-Backed Memory .............................................................................................. Power Control Using HIB ............................................................................................. Power Control Using VDD3ON Mode ........................................................................... Initiating Hibernate ...................................................................................................... Waking from Hibernate ................................................................................................ Arbitrary Power Removal ............................................................................................. Interrupts and Status ................................................................................................... Initialization and Configuration ..................................................................................... Initialization ................................................................................................................. RTC Match Functionality (No Hibernation) .................................................................... RTC Match/Wake-Up from Hibernation ......................................................................... External Wake-Up from Hibernation .............................................................................. RTC or External Wake-Up from Hibernation .................................................................. Register Map .............................................................................................................. Register Descriptions .................................................................................................. 459 459 460 460 461 462 463 464 466 466 466 466 466 467 467 468 468 469 469 469 470 470 471 8 Internal Memory ................................................................................................... 489 8.1 8.2 8.2.1 8.2.2 8.2.3 8.2.4 8.3 8.4 8.5 8.6 Block Diagram ............................................................................................................ 489 Functional Description ................................................................................................. 490 SRAM ........................................................................................................................ 490 ROM .......................................................................................................................... 491 Flash Memory ............................................................................................................. 493 EEPROM .................................................................................................................... 499 Register Map .............................................................................................................. 505 Flash Memory Register Descriptions (Flash Control Offset) ............................................ 506 EEPROM Register Descriptions (EEPROM Offset) ........................................................ 524 Memory Register Descriptions (System Control Offset) .................................................. 541 9 Micro Direct Memory Access (μDMA) ................................................................ 550 9.1 9.2 9.2.1 Block Diagram ............................................................................................................ 551 Functional Description ................................................................................................. 551 Channel Assignments .................................................................................................. 552 June 12, 2014 5 Texas Instruments-Production Data Table of Contents 9.2.2 9.2.3 9.2.4 9.2.5 9.2.6 9.2.7 9.2.8 9.2.9 9.2.10 9.3 9.3.1 9.3.2 9.3.3 9.3.4 9.3.5 9.4 9.5 9.6 Priority ........................................................................................................................ 553 Arbitration Size ............................................................................................................ 553 Request Types ............................................................................................................ 553 Channel Configuration ................................................................................................. 554 Transfer Modes ........................................................................................................... 556 Transfer Size and Increment ........................................................................................ 564 Peripheral Interface ..................................................................................................... 564 Software Request ........................................................................................................ 564 Interrupts and Errors .................................................................................................... 565 Initialization and Configuration ..................................................................................... 565 Module Initialization ..................................................................................................... 565 Configuring a Memory-to-Memory Transfer ................................................................... 566 Configuring a Peripheral for Simple Transmit ................................................................ 567 Configuring a Peripheral for Ping-Pong Receive ............................................................ 569 Configuring Channel Assignments ................................................................................ 571 Register Map .............................................................................................................. 571 μDMA Channel Control Structure ................................................................................. 573 μDMA Register Descriptions ........................................................................................ 580 10 General-Purpose Input/Outputs (GPIOs) ........................................................... 614 10.1 10.2 10.2.1 10.2.2 10.2.3 10.2.4 10.2.5 10.2.6 10.3 10.4 10.5 Signal Description ....................................................................................................... 614 Functional Description ................................................................................................. 617 Data Control ............................................................................................................... 618 Interrupt Control .......................................................................................................... 619 Mode Control .............................................................................................................. 620 Commit Control ........................................................................................................... 621 Pad Control ................................................................................................................. 621 Identification ............................................................................................................... 621 Initialization and Configuration ..................................................................................... 621 Register Map .............................................................................................................. 623 Register Descriptions .................................................................................................. 626 11 General-Purpose Timers ...................................................................................... 669 11.1 11.2 11.3 11.3.1 11.3.2 11.3.3 11.3.4 11.3.5 11.3.6 11.3.7 11.4 11.4.1 11.4.2 11.4.3 11.4.4 11.4.5 11.5 Block Diagram ............................................................................................................ 670 Signal Description ....................................................................................................... 671 Functional Description ................................................................................................. 672 GPTM Reset Conditions .............................................................................................. 673 Timer Modes ............................................................................................................... 674 Wait-for-Trigger Mode .................................................................................................. 683 Synchronizing GP Timer Blocks ................................................................................... 684 DMA Operation ........................................................................................................... 685 Accessing Concatenated 16/32-Bit GPTM Register Values ............................................ 685 Accessing Concatenated 32/64-Bit Wide GPTM Register Values .................................... 685 Initialization and Configuration ..................................................................................... 687 One-Shot/Periodic Timer Mode .................................................................................... 687 Real-Time Clock (RTC) Mode ...................................................................................... 688 Input Edge-Count Mode ............................................................................................... 688 Input Edge Time Mode ................................................................................................. 689 PWM Mode ................................................................................................................. 689 Register Map .............................................................................................................. 690 6 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 11.6 Register Descriptions .................................................................................................. 691 12 Watchdog Timers ................................................................................................. 739 12.1 12.2 12.2.1 12.3 12.4 12.5 Block Diagram ............................................................................................................ Functional Description ................................................................................................. Register Access Timing ............................................................................................... Initialization and Configuration ..................................................................................... Register Map .............................................................................................................. Register Descriptions .................................................................................................. 740 740 741 741 741 742 13 Analog-to-Digital Converter (ADC) ..................................................................... 764 13.1 13.2 13.3 13.3.1 13.3.2 13.3.3 13.3.4 13.3.5 13.3.6 13.3.7 13.4 13.4.1 13.4.2 13.5 13.6 Block Diagram ............................................................................................................ 765 Signal Description ....................................................................................................... 766 Functional Description ................................................................................................. 767 Sample Sequencers .................................................................................................... 767 Module Control ............................................................................................................ 768 Hardware Sample Averaging Circuit ............................................................................. 771 Analog-to-Digital Converter .......................................................................................... 772 Differential Sampling ................................................................................................... 775 Internal Temperature Sensor ........................................................................................ 777 Digital Comparator Unit ............................................................................................... 778 Initialization and Configuration ..................................................................................... 782 Module Initialization ..................................................................................................... 782 Sample Sequencer Configuration ................................................................................. 783 Register Map .............................................................................................................. 783 Register Descriptions .................................................................................................. 785 14 Universal Asynchronous Receivers/Transmitters (UARTs) ............................. 855 14.1 Block Diagram ............................................................................................................ 14.2 Signal Description ....................................................................................................... 14.3 Functional Description ................................................................................................. 14.3.1 Transmit/Receive Logic ............................................................................................... 14.3.2 Baud-Rate Generation ................................................................................................. 14.3.3 Data Transmission ...................................................................................................... 14.3.4 Serial IR (SIR) ............................................................................................................. 14.3.5 ISO 7816 Support ....................................................................................................... 14.3.6 Modem Handshake Support ......................................................................................... 14.3.7 9-Bit UART Mode ........................................................................................................ 14.3.8 FIFO Operation ........................................................................................................... 14.3.9 Interrupts .................................................................................................................... 14.3.10 Loopback Operation .................................................................................................... 14.3.11 DMA Operation ........................................................................................................... 14.4 Initialization and Configuration ..................................................................................... 14.5 Register Map .............................................................................................................. 14.6 Register Descriptions .................................................................................................. 856 856 857 857 858 859 859 860 861 862 862 862 863 864 864 865 867 15 Synchronous Serial Interface (SSI) .................................................................... 914 15.1 15.2 15.3 15.3.1 Block Diagram ............................................................................................................ Signal Description ....................................................................................................... Functional Description ................................................................................................. Bit Rate Generation ..................................................................................................... June 12, 2014 915 915 916 916 7 Texas Instruments-Production Data Table of Contents 15.3.2 15.3.3 15.3.4 15.3.5 15.4 15.5 15.6 FIFO Operation ........................................................................................................... Interrupts .................................................................................................................... Frame Formats ........................................................................................................... DMA Operation ........................................................................................................... Initialization and Configuration ..................................................................................... Register Map .............................................................................................................. Register Descriptions .................................................................................................. 917 917 918 926 927 929 930 16 Inter-Integrated Circuit (I2C) Interface ................................................................ 959 16.1 16.2 16.3 16.3.1 16.3.2 16.3.3 16.3.4 16.3.5 16.4 16.4.1 16.4.2 16.5 16.6 16.7 16.8 Block Diagram ............................................................................................................ 960 Signal Description ....................................................................................................... 960 Functional Description ................................................................................................. 961 I2C Bus Functional Overview ........................................................................................ 961 Available Speed Modes ............................................................................................... 965 Interrupts .................................................................................................................... 967 Loopback Operation .................................................................................................... 968 Command Sequence Flow Charts ................................................................................ 969 Initialization and Configuration ..................................................................................... 977 Configure the I2C Module to Transmit a Single Byte as a Master .................................... 977 Configure the I2C Master to High Speed Mode .............................................................. 978 Register Map .............................................................................................................. 979 Register Descriptions (I2C Master) ............................................................................... 980 Register Descriptions (I2C Slave) ................................................................................. 997 Register Descriptions (I2C Status and Control) ............................................................ 1007 17 Controller Area Network (CAN) Module ........................................................... 1010 17.1 Block Diagram ........................................................................................................... 1011 17.2 Signal Description ..................................................................................................... 1011 17.3 Functional Description ............................................................................................... 1012 17.3.1 Initialization ............................................................................................................... 1013 17.3.2 Operation .................................................................................................................. 1013 17.3.3 Transmitting Message Objects ................................................................................... 1014 17.3.4 Configuring a Transmit Message Object ...................................................................... 1015 17.3.5 Updating a Transmit Message Object ......................................................................... 1016 17.3.6 Accepting Received Message Objects ........................................................................ 1016 17.3.7 Receiving a Data Frame ............................................................................................ 1017 17.3.8 Receiving a Remote Frame ........................................................................................ 1017 17.3.9 Receive/Transmit Priority ........................................................................................... 1018 17.3.10 Configuring a Receive Message Object ...................................................................... 1018 17.3.11 Handling of Received Message Objects ...................................................................... 1019 17.3.12 Handling of Interrupts ................................................................................................ 1021 17.3.13 Test Mode ................................................................................................................. 1022 17.3.14 Bit Timing Configuration Error Considerations ............................................................. 1024 17.3.15 Bit Time and Bit Rate ................................................................................................. 1024 17.3.16 Calculating the Bit Timing Parameters ........................................................................ 1026 17.4 Register Map ............................................................................................................ 1029 17.5 CAN Register Descriptions ......................................................................................... 1030 18 Analog Comparators .......................................................................................... 1060 18.1 Block Diagram ........................................................................................................... 1061 8 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 18.2 18.3 18.3.1 18.4 18.5 18.6 Signal Description ..................................................................................................... Functional Description ............................................................................................... Internal Reference Programming ................................................................................ Initialization and Configuration .................................................................................... Register Map ............................................................................................................ Register Descriptions ................................................................................................. 1061 1062 1063 1065 1065 1066 19 Pin Diagram ........................................................................................................ 1075 20 Signal Tables ...................................................................................................... 1076 20.1 20.2 20.3 20.4 20.5 20.6 Signals by Pin Number .............................................................................................. Signals by Signal Name ............................................................................................. Signals by Function, Except for GPIO ......................................................................... GPIO Pins and Alternate Functions ............................................................................ Possible Pin Assignments for Alternate Functions ....................................................... Connections for Unused Signals ................................................................................. 21 Electrical Characteristics .................................................................................. 1096 1077 1082 1087 1091 1093 1095 21.1 Maximum Ratings ...................................................................................................... 1096 21.2 Operating Characteristics ........................................................................................... 1097 21.3 Recommended Operating Conditions ......................................................................... 1098 21.4 Load Conditions ........................................................................................................ 1100 21.5 JTAG and Boundary Scan .......................................................................................... 1101 21.6 Power and Brown-Out ............................................................................................... 1103 21.6.1 VDDA Levels ............................................................................................................ 1103 21.6.2 VDD Levels ............................................................................................................... 1104 21.6.3 VDDC Levels ............................................................................................................ 1105 21.6.4 VDD Glitches ............................................................................................................ 1106 21.6.5 VDD Droop Response ............................................................................................... 1106 21.7 Reset ........................................................................................................................ 1108 21.8 On-Chip Low Drop-Out (LDO) Regulator ..................................................................... 1111 21.9 Clocks ...................................................................................................................... 1112 21.9.1 PLL Specifications ..................................................................................................... 1112 21.9.2 PIOSC Specifications ................................................................................................ 1113 21.9.3 Low-Frequency Internal Oscillator (LFIOSC) Specifications .......................................... 1113 21.9.4 Hibernation Clock Source Specifications ..................................................................... 1113 21.9.5 Main Oscillator Specifications ..................................................................................... 1114 21.9.6 System Clock Specification with ADC Operation .......................................................... 1118 21.10 Sleep Modes ............................................................................................................. 1119 21.11 Hibernation Module ................................................................................................... 1121 21.12 Flash Memory and EEPROM ..................................................................................... 1122 21.13 Input/Output Pin Characteristics ................................................................................. 1123 21.13.1 GPIO Module Characteristics ..................................................................................... 1123 21.13.2 Types of I/O Pins and ESD Protection ......................................................................... 1123 21.14 Analog-to-Digital Converter (ADC) .............................................................................. 1127 21.15 Synchronous Serial Interface (SSI) ............................................................................. 1130 21.16 Inter-Integrated Circuit (I2C) Interface ......................................................................... 1133 21.17 Analog Comparator ................................................................................................... 1134 21.18 Current Consumption ................................................................................................. 1136 A Package Information .......................................................................................... 1139 June 12, 2014 9 Texas Instruments-Production Data Table of Contents A.1 A.2 A.3 A.4 Orderable Devices ..................................................................................................... Device Nomenclature ................................................................................................ Device Markings ........................................................................................................ Packaging Diagram ................................................................................................... 10 1139 1139 1140 1141 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller List of Figures Figure 1-1. Figure 2-1. Figure 2-2. Figure 2-3. Figure 2-4. Figure 2-5. Figure 2-6. Figure 2-7. Figure 3-1. Figure 3-2. Figure 4-1. Figure 4-2. Figure 4-3. Figure 4-4. Figure 4-5. Figure 5-1. Figure 5-2. Figure 5-3. Figure 5-4. Figure 5-5. Figure 5-6. Figure 7-1. Figure 7-2. Figure 7-3. Figure 7-4. Figure 7-5. Figure 7-6. Figure 8-1. Figure 8-2. Figure 9-1. Figure 9-2. Figure 9-3. Figure 9-4. Figure 9-5. Figure 9-6. Figure 10-1. Figure 10-2. Figure 10-3. Figure 10-4. Figure 11-1. Figure 11-2. Figure 11-3. Figure 11-4. Figure 11-5. Figure 11-6. Tiva™ TM4C1231H6PM Microcontroller High-Level Block Diagram ......................... 41 CPU Block Diagram ............................................................................................. 61 TPIU Block Diagram ............................................................................................ 62 Cortex-M4F Register Set ...................................................................................... 65 Bit-Band Mapping ................................................................................................ 89 Data Storage ....................................................................................................... 90 Vector Table ........................................................................................................ 97 Exception Stack Frame ...................................................................................... 100 SRD Use Example ............................................................................................. 118 FPU Register Bank ............................................................................................ 121 JTAG Module Block Diagram .............................................................................. 191 Test Access Port State Machine ......................................................................... 194 IDCODE Register Format ................................................................................... 200 BYPASS Register Format ................................................................................... 200 Boundary Scan Register Format ......................................................................... 201 Basic RST Configuration .................................................................................... 205 External Circuitry to Extend Power-On Reset ....................................................... 205 Reset Circuit Controlled by Switch ...................................................................... 206 Power Architecture ............................................................................................ 209 Main Clock Tree ................................................................................................ 211 Module Clock Selection ...................................................................................... 218 Hibernation Module Block Diagram ..................................................................... 459 Using a Crystal as the Hibernation Clock Source with a Single Battery Source ...... 461 Using a Dedicated Oscillator as the Hibernation Clock Source with VDD3ON Mode ................................................................................................................ 462 Using a Regulator for Both VDD and VBAT ............................................................ 463 Counter Behavior with a TRIM Value of 0x8002 ................................................... 465 Counter Behavior with a TRIM Value of 0x7FFC .................................................. 465 Internal Memory Block Diagram .......................................................................... 489 EEPROM Block Diagram ................................................................................... 490 μDMA Block Diagram ......................................................................................... 551 Example of Ping-Pong μDMA Transaction ........................................................... 557 Memory Scatter-Gather, Setup and Configuration ................................................ 559 Memory Scatter-Gather, μDMA Copy Sequence .................................................. 560 Peripheral Scatter-Gather, Setup and Configuration ............................................. 562 Peripheral Scatter-Gather, μDMA Copy Sequence ............................................... 563 Digital I/O Pads ................................................................................................. 617 Analog/Digital I/O Pads ...................................................................................... 618 GPIODATA Write Example ................................................................................. 619 GPIODATA Read Example ................................................................................. 619 GPTM Module Block Diagram ............................................................................ 670 Reading the RTC Value ...................................................................................... 677 Input Edge-Count Mode Example, Counting Down ............................................... 679 16-Bit Input Edge-Time Mode Example ............................................................... 680 16-Bit PWM Mode Example ................................................................................ 682 CCP Output, GPTMTnMATCHR > GPTMTnILR ................................................... 682 June 12, 2014 11 Texas Instruments-Production Data Table of Contents Figure 11-7. Figure 11-8. Figure 11-9. Figure 12-1. Figure 13-1. Figure 13-2. Figure 13-3. Figure 13-4. Figure 13-5. Figure 13-6. Figure 13-7. Figure 13-8. Figure 13-9. Figure 13-10. Figure 13-11. Figure 13-12. Figure 13-13. Figure 13-14. Figure 14-1. Figure 14-2. Figure 14-3. Figure 15-1. Figure 15-2. Figure 15-3. Figure 15-4. Figure 15-5. Figure 15-6. Figure 15-7. Figure 15-8. Figure 15-9. Figure 15-10. Figure 15-11. Figure 15-12. Figure 16-1. Figure 16-2. Figure 16-3. Figure 16-4. Figure 16-5. Figure 16-6. Figure 16-7. Figure 16-8. Figure 16-9. Figure 16-10. Figure 16-11. Figure 16-12. Figure 16-13. Figure 16-14. Figure 16-15. CCP Output, GPTMTnMATCHR = GPTMTnILR ................................................... 683 CCP Output, GPTMTnILR > GPTMTnMATCHR ................................................... 683 Timer Daisy Chain ............................................................................................. 684 WDT Module Block Diagram .............................................................................. 740 Implementation of Two ADC Blocks .................................................................... 765 ADC Module Block Diagram ............................................................................... 766 ADC Sample Phases ......................................................................................... 769 Doubling the ADC Sample Rate .......................................................................... 770 Skewed Sampling .............................................................................................. 770 Sample Averaging Example ............................................................................... 772 ADC Input Equivalency ...................................................................................... 773 ADC Voltage Reference ..................................................................................... 774 ADC Conversion Result ..................................................................................... 775 Differential Voltage Representation ..................................................................... 777 Internal Temperature Sensor Characteristic ......................................................... 778 Low-Band Operation (CIC=0x0) .......................................................................... 780 Mid-Band Operation (CIC=0x1) .......................................................................... 781 High-Band Operation (CIC=0x3) ......................................................................... 782 UART Module Block Diagram ............................................................................. 856 UART Character Frame ..................................................................................... 858 IrDA Data Modulation ......................................................................................... 860 SSI Module Block Diagram ................................................................................. 915 TI Synchronous Serial Frame Format (Single Transfer) ........................................ 919 TI Synchronous Serial Frame Format (Continuous Transfer) ................................ 920 Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0 .......................... 921 Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0 .................. 921 Freescale SPI Frame Format with SPO=0 and SPH=1 ......................................... 922 Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0 ............... 923 Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0 ........ 923 Freescale SPI Frame Format with SPO=1 and SPH=1 ......................................... 924 MICROWIRE Frame Format (Single Frame) ........................................................ 925 MICROWIRE Frame Format (Continuous Transfer) ............................................. 926 MICROWIRE Frame Format, SSInFss Input Setup and Hold Requirements .......... 926 I2C Block Diagram ............................................................................................. 960 I2C Bus Configuration ........................................................................................ 961 START and STOP Conditions ............................................................................. 961 Complete Data Transfer with a 7-Bit Address ....................................................... 962 R/S Bit in First Byte ............................................................................................ 962 Data Validity During Bit Transfer on the I2C Bus ................................................... 963 High-Speed Data Format ................................................................................... 967 Master Single TRANSMIT .................................................................................. 970 Master Single RECEIVE ..................................................................................... 971 Master TRANSMIT of Multiple Data Bytes ........................................................... 972 Master RECEIVE of Multiple Data Bytes ............................................................. 973 Master RECEIVE with Repeated START after Master TRANSMIT ........................ 974 Master TRANSMIT with Repeated START after Master RECEIVE ........................ 975 Standard High Speed Mode Master Transmit ....................................................... 976 Slave Command Sequence ................................................................................ 977 12 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 17-1. Figure 17-2. Figure 17-3. Figure 17-4. Figure 18-1. Figure 18-2. Figure 18-3. Figure 19-1. Figure 21-1. Figure 21-2. Figure 21-3. Figure 21-4. Figure 21-5. Figure 21-6. Figure 21-7. Figure 21-8. Figure 21-9. Figure 21-10. Figure 21-11. Figure 21-12. Figure 21-13. Figure 21-14. Figure 21-15. Figure 21-16. Figure 21-17. Figure 21-18. Figure 21-19. Figure 21-20. Figure 21-21. Figure 21-22. Figure 21-23. Figure A-1. Figure A-2. CAN Controller Block Diagram .......................................................................... 1011 CAN Data/Remote Frame ................................................................................. 1012 Message Objects in a FIFO Buffer .................................................................... 1021 CAN Bit Time ................................................................................................... 1025 Analog Comparator Module Block Diagram ....................................................... 1061 Structure of Comparator Unit ............................................................................ 1062 Comparator Internal Reference Structure .......................................................... 1063 64-Pin LQFP Package Pin Diagram .................................................................. 1075 Load Conditions ............................................................................................... 1100 JTAG Test Clock Input Timing ........................................................................... 1101 JTAG Test Access Port (TAP) Timing ................................................................ 1102 Power Assertions versus VDDA Levels ............................................................. 1104 Power and Brown-Out Assertions versus VDD Levels ........................................ 1105 POK assertion vs VDDC ................................................................................... 1106 POR-BOR0-BOR1 VDD Glitch Response .......................................................... 1106 POR-BOR0-BOR1 VDD Droop Response ......................................................... 1107 Digital Power-On Reset Timing ......................................................................... 1108 Brown-Out Reset Timing .................................................................................. 1109 External Reset Timing (RST) ............................................................................ 1109 Software Reset Timing ..................................................................................... 1109 Watchdog Reset Timing ................................................................................... 1109 MOSC Failure Reset Timing ............................................................................. 1110 Hibernation Module Timing ............................................................................... 1121 ESD Protection on Fail-Safe Pins ...................................................................... 1124 ESD Protection on Non-Fail-Safe Pins .............................................................. 1125 ADC Input Equivalency Diagram ....................................................................... 1129 SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing Measurement .................................................................................................. 1131 SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer ............... 1131 Master Mode SSI Timing for SPI Frame Format (FRF=00), with SPH=1 .............. 1132 Slave Mode SSI Timing for SPI Frame Format (FRF=00), with SPH=1 ................ 1132 I2C Timing ....................................................................................................... 1133 Key to Part Numbers ........................................................................................ 1139 TM4C1231H6PM 64-Pin LQFP Package Diagram ............................................. 1141 June 12, 2014 13 Texas Instruments-Production Data Table of Contents List of Tables Table 1. Table 2. Table 1-1. Table 2-1. Table 2-2. Table 2-3. Table 2-4. Table 2-5. Table 2-6. Table 2-7. Table 2-8. Table 2-9. Table 2-10. Table 2-11. Table 2-12. Table 2-13. Table 3-1. Table 3-2. Table 3-3. Table 3-4. Table 3-5. Table 3-6. Table 3-7. Table 3-8. Table 3-9. Table 3-10. Table 4-1. Table 4-2. Table 4-3. Table 5-1. Table 5-2. Table 5-3. Table 5-4. Table 5-5. Table 5-6. Table 5-7. Table 5-8. Table 6-1. Table 7-1. Table 7-2. Table 7-3. Table 8-1. Table 8-2. Table 8-3. Table 9-1. Table 9-2. Revision History .................................................................................................. 32 Documentation Conventions ................................................................................ 37 TM4C1231H6PM Microcontroller Features ............................................................ 40 Summary of Processor Mode, Privilege Level, and Stack Use ................................ 64 Processor Register Map ....................................................................................... 65 PSR Register Combinations ................................................................................. 71 Memory Map ....................................................................................................... 82 Memory Access Behavior ..................................................................................... 85 SRAM Memory Bit-Banding Regions .................................................................... 87 Peripheral Memory Bit-Banding Regions ............................................................... 87 Exception Types .................................................................................................. 93 Interrupts ............................................................................................................ 94 Exception Return Behavior ................................................................................. 101 Faults ............................................................................................................... 102 Fault Status and Fault Address Registers ............................................................ 103 Cortex-M4F Instruction Summary ....................................................................... 105 Core Peripheral Register Regions ....................................................................... 112 Memory Attributes Summary .............................................................................. 116 TEX, S, C, and B Bit Field Encoding ................................................................... 118 Cache Policy for Memory Attribute Encoding ....................................................... 119 AP Bit Field Encoding ........................................................................................ 119 Memory Region Attributes for Tiva™ C Series Microcontrollers ............................. 120 QNaN and SNaN Handling ................................................................................. 123 Peripherals Register Map ................................................................................... 124 Interrupt Priority Levels ...................................................................................... 154 Example SIZE Field Values ................................................................................ 182 JTAG_SWD_SWO Signals (64LQFP) ................................................................. 191 JTAG Port Pins State after Power-On Reset or RST assertion .............................. 192 JTAG Instruction Register Commands ................................................................. 198 System Control & Clocks Signals (64LQFP) ........................................................ 202 Reset Sources ................................................................................................... 203 Clock Source Options ........................................................................................ 210 Possible System Clock Frequencies Using the SYSDIV Field ............................... 212 Examples of Possible System Clock Frequencies Using the SYSDIV2 Field .......... 213 Examples of Possible System Clock Frequencies with DIV400=1 ......................... 213 System Control Register Map ............................................................................. 220 RCC2 Fields that Override RCC Fields ............................................................... 247 System Exception Register Map ......................................................................... 450 Hibernate Signals (64LQFP) ............................................................................... 459 Hibernation Module Clock Operation ................................................................... 468 Hibernation Module Register Map ....................................................................... 470 Flash Memory Protection Policy Combinations .................................................... 494 User-Programmable Flash Memory Resident Registers ....................................... 498 Flash Register Map ............................................................................................ 505 μDMA Channel Assignments .............................................................................. 552 Request Type Support ....................................................................................... 554 14 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 9-3. Table 9-4. Table 9-5. Table 9-6. Table 9-7. Table 9-8. Table 9-9. Table 9-10. Table 9-11. Table 9-12. Control Structure Memory Map ........................................................................... 555 Channel Control Structure .................................................................................. 555 μDMA Read Example: 8-Bit Peripheral ................................................................ 564 μDMA Interrupt Assignments .............................................................................. 565 Channel Control Structure Offsets for Channel 30 ................................................ 566 Channel Control Word Configuration for Memory Transfer Example ...................... 567 Channel Control Structure Offsets for Channel 7 .................................................. 568 Channel Control Word Configuration for Peripheral Transmit Example .................. 568 Primary and Alternate Channel Control Structure Offsets for Channel 8 ................. 569 Channel Control Word Configuration for Peripheral Ping-Pong Receive Example ............................................................................................................ 570 Table 9-13. μDMA Register Map .......................................................................................... 572 Table 10-1. GPIO Pins With Special Considerations .............................................................. 615 Table 10-2. GPIO Pins and Alternate Functions (64LQFP) ..................................................... 615 Table 10-3. GPIO Pad Configuration Examples ..................................................................... 622 Table 10-4. GPIO Interrupt Configuration Example ................................................................ 623 Table 10-5. GPIO Pins With Special Considerations .............................................................. 624 Table 10-6. GPIO Register Map ........................................................................................... 625 Table 10-7. GPIO Pins With Special Considerations .............................................................. 636 Table 10-8. GPIO Pins With Special Considerations .............................................................. 642 Table 10-9. GPIO Pins With Special Considerations .............................................................. 644 Table 10-10. GPIO Pins With Special Considerations .............................................................. 647 Table 10-11. GPIO Pins With Special Considerations .............................................................. 653 Table 11-1. Available CCP Pins ............................................................................................ 671 Table 11-2. General-Purpose Timers Signals (64LQFP) ......................................................... 671 Table 11-3. General-Purpose Timer Capabilities .................................................................... 673 Table 11-4. Counter Values When the Timer is Enabled in Periodic or One-Shot Modes .......... 674 Table 11-5. 16-Bit Timer With Prescaler Configurations ......................................................... 675 Table 11-6. 32-Bit Timer (configured in 32/64-bit mode) With Prescaler Configurations ............ 676 Table 11-7. Counter Values When the Timer is Enabled in RTC Mode .................................... 676 Table 11-8. Counter Values When the Timer is Enabled in Input Edge-Count Mode ................. 678 Table 11-9. Counter Values When the Timer is Enabled in Input Event-Count Mode ................ 679 Table 11-10. Counter Values When the Timer is Enabled in PWM Mode ................................... 681 Table 11-11. Timeout Actions for GPTM Modes ...................................................................... 684 Table 11-12. Timers Register Map .......................................................................................... 691 Table 12-1. Watchdog Timers Register Map .......................................................................... 742 Table 13-1. ADC Signals (64LQFP) ...................................................................................... 766 Table 13-2. Samples and FIFO Depth of Sequencers ............................................................ 767 Table 13-3. Differential Sampling Pairs ................................................................................. 775 Table 13-4. ADC Register Map ............................................................................................. 783 Table 14-1. UART Signals (64LQFP) .................................................................................... 857 Table 14-2. Flow Control Mode ............................................................................................. 861 Table 14-3. UART Register Map ........................................................................................... 866 Table 15-1. SSI Signals (64LQFP) ........................................................................................ 916 Table 15-2. SSI Register Map .............................................................................................. 929 Table 16-1. I2C Signals (64LQFP) ........................................................................................ 960 Table 16-2. Examples of I2C Master Timer Period Versus Speed Mode ................................... 966 Table 16-3. Examples of I2C Master Timer Period in High-Speed Mode .................................. 967 June 12, 2014 15 Texas Instruments-Production Data Table of Contents Table 16-4. Table 16-5. Table 17-1. Table 17-2. Table 17-3. Table 17-4. Table 17-5. Table 18-1. Table 18-2. Table 18-3. Table 18-4. Table 18-5. Table 20-1. Table 20-2. Table 20-3. Table 20-4. Table 20-5. Table 20-6. Table 20-7. Table 21-1. Table 21-2. Table 21-3. Table 21-4. Table 21-5. Table 21-6. Table 21-7. Table 21-8. Table 21-9. Table 21-10. Table 21-11. Table 21-12. Table 21-13. Table 21-14. Table 21-15. Table 21-16. Table 21-17. Table 21-18. Table 21-19. Table 21-20. Table 21-21. Table 21-22. Table 21-23. Table 21-24. Table 21-25. Table 21-26. Table 21-27. Inter-Integrated Circuit (I2C) Interface Register Map ............................................. 979 Write Field Decoding for I2CMCS[3:0] Field ......................................................... 985 Controller Area Network Signals (64LQFP) ........................................................ 1012 Message Object Configurations ........................................................................ 1017 CAN Protocol Ranges ...................................................................................... 1025 CANBIT Register Values .................................................................................. 1025 CAN Register Map ........................................................................................... 1029 Analog Comparators Signals (64LQFP) ............................................................. 1061 Internal Reference Voltage and ACREFCTL Field Values ................................... 1063 Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 0 .......................................................................................................... 1064 Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 1 .......................................................................................................... 1064 Analog Comparators Register Map ................................................................... 1065 GPIO Pins With Special Considerations ............................................................ 1076 Signals by Pin Number ..................................................................................... 1077 Signals by Signal Name ................................................................................... 1082 Signals by Function, Except for GPIO ............................................................... 1087 GPIO Pins and Alternate Functions ................................................................... 1091 Possible Pin Assignments for Alternate Functions .............................................. 1093 Connections for Unused Signals (64-Pin LQFP) ................................................. 1095 Absolute Maximum Ratings .............................................................................. 1096 ESD Absolute Maximum Ratings ...................................................................... 1096 Temperature Characteristics ............................................................................. 1097 Thermal Characteristics ................................................................................... 1097 Recommended DC Operating Conditions .......................................................... 1098 Recommended GPIO Pad Operating Conditions ................................................ 1098 GPIO Current Restrictions ................................................................................ 1098 GPIO Package Side Assignments ..................................................................... 1099 JTAG Characteristics ....................................................................................... 1101 Power-On and Brown-Out Levels ...................................................................... 1103 Reset Characteristics ....................................................................................... 1108 LDO Regulator Characteristics ......................................................................... 1111 Phase Locked Loop (PLL) Characteristics ......................................................... 1112 Actual PLL Frequency ...................................................................................... 1112 PIOSC Clock Characteristics ............................................................................ 1113 Low-Frequency internal Oscillator Characteristics .............................................. 1113 Hibernation Oscillator Input Characteristics ........................................................ 1113 Main Oscillator Input Characteristics ................................................................. 1114 Crystal Parameters .......................................................................................... 1116 Supported MOSC Crystal Frequencies .............................................................. 1117 System Clock Characteristics with ADC Operation ............................................. 1118 Sleep Modes AC Characteristics ....................................................................... 1119 Time to Wake with Respect to Low-Power Modes .............................................. 1119 Hibernation Module Battery Characteristics ....................................................... 1121 Hibernation Module AC Characteristics ............................................................. 1121 Flash Memory Characteristics ........................................................................... 1122 EEPROM Characteristics ................................................................................. 1122 16 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 21-28. Table 21-29. Table 21-30. Table 21-31. Table 21-32. Table 21-33. Table 21-34. Table 21-35. Table 21-36. Table 21-37. GPIO Module Characteristics ............................................................................ 1123 Pad Voltage/Current Characteristics for Fail-Safe Pins ....................................... 1124 Fail-Safe GPIOs that Require an External Pull-up .............................................. 1125 Non-Fail-Safe I/O Pad Voltage/Current Characteristics ....................................... 1125 ADC Electrical Characteristics .......................................................................... 1127 SSI Characteristics .......................................................................................... 1130 I2C Characteristics ........................................................................................... 1133 Analog Comparator Characteristics ................................................................... 1134 Analog Comparator Voltage Reference Characteristics ...................................... 1134 Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 0 .......................................................................................................... 1134 Table 21-38. Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 1 .......................................................................................................... 1135 Table 21-39. Current Consumption ....................................................................................... 1136 June 12, 2014 17 Texas Instruments-Production Data Table of Contents List of Registers The Cortex-M4F Processor ........................................................................................................... 59 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Cortex General-Purpose Register 0 (R0) ........................................................................... 67 Cortex General-Purpose Register 1 (R1) ........................................................................... 67 Cortex General-Purpose Register 2 (R2) ........................................................................... 67 Cortex General-Purpose Register 3 (R3) ........................................................................... 67 Cortex General-Purpose Register 4 (R4) ........................................................................... 67 Cortex General-Purpose Register 5 (R5) ........................................................................... 67 Cortex General-Purpose Register 6 (R6) ........................................................................... 67 Cortex General-Purpose Register 7 (R7) ........................................................................... 67 Cortex General-Purpose Register 8 (R8) ........................................................................... 67 Cortex General-Purpose Register 9 (R9) ........................................................................... 67 Cortex General-Purpose Register 10 (R10) ....................................................................... 67 Cortex General-Purpose Register 11 (R11) ........................................................................ 67 Cortex General-Purpose Register 12 (R12) ....................................................................... 67 Stack Pointer (SP) ........................................................................................................... 68 Link Register (LR) ............................................................................................................ 69 Program Counter (PC) ..................................................................................................... 70 Program Status Register (PSR) ........................................................................................ 71 Priority Mask Register (PRIMASK) .................................................................................... 75 Fault Mask Register (FAULTMASK) .................................................................................. 76 Base Priority Mask Register (BASEPRI) ............................................................................ 77 Control Register (CONTROL) ........................................................................................... 78 Floating-Point Status Control (FPSC) ................................................................................ 80 Cortex-M4 Peripherals ................................................................................................................. 112 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: SysTick Control and Status Register (STCTRL), offset 0x010 ........................................... 128 SysTick Reload Value Register (STRELOAD), offset 0x014 .............................................. 130 SysTick Current Value Register (STCURRENT), offset 0x018 ........................................... 131 Interrupt 0-31 Set Enable (EN0), offset 0x100 .................................................................. 132 Interrupt 32-63 Set Enable (EN1), offset 0x104 ................................................................ 132 Interrupt 64-95 Set Enable (EN2), offset 0x108 ................................................................ 132 Interrupt 96-127 Set Enable (EN3), offset 0x10C ............................................................. 132 Interrupt 128-138 Set Enable (EN4), offset 0x110 ............................................................ 133 Interrupt 0-31 Clear Enable (DIS0), offset 0x180 .............................................................. 134 Interrupt 32-63 Clear Enable (DIS1), offset 0x184 ............................................................ 134 Interrupt 64-95 Clear Enable (DIS2), offset 0x188 ............................................................ 134 Interrupt 96-127 Clear Enable (DIS3), offset 0x18C .......................................................... 134 Interrupt 128-138 Clear Enable (DIS4), offset 0x190 ........................................................ 135 Interrupt 0-31 Set Pending (PEND0), offset 0x200 ........................................................... 136 Interrupt 32-63 Set Pending (PEND1), offset 0x204 ......................................................... 136 Interrupt 64-95 Set Pending (PEND2), offset 0x208 ......................................................... 136 Interrupt 96-127 Set Pending (PEND3), offset 0x20C ....................................................... 136 Interrupt 128-138 Set Pending (PEND4), offset 0x210 ...................................................... 137 Interrupt 0-31 Clear Pending (UNPEND0), offset 0x280 ................................................... 138 Interrupt 32-63 Clear Pending (UNPEND1), offset 0x284 .................................................. 138 Interrupt 64-95 Clear Pending (UNPEND2), offset 0x288 .................................................. 138 18 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 31: Register 32: Register 33: Register 34: Register 35: Register 36: Register 37: Register 38: Register 39: Register 40: Register 41: Register 42: Register 43: Register 44: Register 45: Register 46: Register 47: Register 48: Register 49: Register 50: Register 51: Register 52: Register 53: Register 54: Register 55: Register 56: Register 57: Register 58: Register 59: Register 60: Register 61: Register 62: Register 63: Register 64: Register 65: Register 66: Register 67: Register 68: Register 69: Interrupt 96-127 Clear Pending (UNPEND3), offset 0x28C ............................................... 138 Interrupt 128-138 Clear Pending (UNPEND4), offset 0x290 .............................................. 139 Interrupt 0-31 Active Bit (ACTIVE0), offset 0x300 ............................................................. 140 Interrupt 32-63 Active Bit (ACTIVE1), offset 0x304 ........................................................... 140 Interrupt 64-95 Active Bit (ACTIVE2), offset 0x308 ........................................................... 140 Interrupt 96-127 Active Bit (ACTIVE3), offset 0x30C ........................................................ 140 Interrupt 128-138 Active Bit (ACTIVE4), offset 0x310 ....................................................... 141 Interrupt 0-3 Priority (PRI0), offset 0x400 ......................................................................... 142 Interrupt 4-7 Priority (PRI1), offset 0x404 ......................................................................... 142 Interrupt 8-11 Priority (PRI2), offset 0x408 ....................................................................... 142 Interrupt 12-15 Priority (PRI3), offset 0x40C .................................................................... 142 Interrupt 16-19 Priority (PRI4), offset 0x410 ..................................................................... 142 Interrupt 20-23 Priority (PRI5), offset 0x414 ..................................................................... 142 Interrupt 24-27 Priority (PRI6), offset 0x418 ..................................................................... 142 Interrupt 28-31 Priority (PRI7), offset 0x41C .................................................................... 142 Interrupt 32-35 Priority (PRI8), offset 0x420 ..................................................................... 142 Interrupt 36-39 Priority (PRI9), offset 0x424 ..................................................................... 142 Interrupt 40-43 Priority (PRI10), offset 0x428 ................................................................... 142 Interrupt 44-47 Priority (PRI11), offset 0x42C ................................................................... 142 Interrupt 48-51 Priority (PRI12), offset 0x430 ................................................................... 142 Interrupt 52-55 Priority (PRI13), offset 0x434 ................................................................... 142 Interrupt 56-59 Priority (PRI14), offset 0x438 ................................................................... 142 Interrupt 60-63 Priority (PRI15), offset 0x43C .................................................................. 142 Interrupt 64-67 Priority (PRI16), offset 0x440 ................................................................... 144 Interrupt 68-71 Priority (PRI17), offset 0x444 ................................................................... 144 Interrupt 72-75 Priority (PRI18), offset 0x448 ................................................................... 144 Interrupt 76-79 Priority (PRI19), offset 0x44C .................................................................. 144 Interrupt 80-83 Priority (PRI20), offset 0x450 ................................................................... 144 Interrupt 84-87 Priority (PRI21), offset 0x454 ................................................................... 144 Interrupt 88-91 Priority (PRI22), offset 0x458 ................................................................... 144 Interrupt 92-95 Priority (PRI23), offset 0x45C .................................................................. 144 Interrupt 96-99 Priority (PRI24), offset 0x460 ................................................................... 144 Interrupt 100-103 Priority (PRI25), offset 0x464 ............................................................... 144 Interrupt 104-107 Priority (PRI26), offset 0x468 ............................................................... 144 Interrupt 108-111 Priority (PRI27), offset 0x46C ............................................................... 144 Interrupt 112-115 Priority (PRI28), offset 0x470 ................................................................ 144 Interrupt 116-119 Priority (PRI29), offset 0x474 ................................................................ 144 Interrupt 120-123 Priority (PRI30), offset 0x478 ............................................................... 144 Interrupt 124-127 Priority (PRI31), offset 0x47C ............................................................... 144 Interrupt 128-131 Priority (PRI32), offset 0x480 ............................................................... 144 Interrupt 132-135 Priority (PRI33), offset 0x484 ............................................................... 144 Interrupt 136-138 Priority (PRI34), offset 0x488 ............................................................... 144 Software Trigger Interrupt (SWTRIG), offset 0xF00 .......................................................... 146 Auxiliary Control (ACTLR), offset 0x008 .......................................................................... 147 CPU ID Base (CPUID), offset 0xD00 ............................................................................... 149 Interrupt Control and State (INTCTRL), offset 0xD04 ........................................................ 150 Vector Table Offset (VTABLE), offset 0xD08 .................................................................... 153 Application Interrupt and Reset Control (APINT), offset 0xD0C ......................................... 154 June 12, 2014 19 Texas Instruments-Production Data Table of Contents Register 70: Register 71: Register 72: Register 73: Register 74: Register 75: Register 76: Register 77: Register 78: Register 79: Register 80: Register 81: Register 82: Register 83: Register 84: Register 85: Register 86: Register 87: Register 88: Register 89: Register 90: Register 91: Register 92: Register 93: Register 94: System Control (SYSCTRL), offset 0xD10 ....................................................................... 156 Configuration and Control (CFGCTRL), offset 0xD14 ....................................................... 158 System Handler Priority 1 (SYSPRI1), offset 0xD18 ......................................................... 160 System Handler Priority 2 (SYSPRI2), offset 0xD1C ........................................................ 161 System Handler Priority 3 (SYSPRI3), offset 0xD20 ......................................................... 162 System Handler Control and State (SYSHNDCTRL), offset 0xD24 .................................... 163 Configurable Fault Status (FAULTSTAT), offset 0xD28 ..................................................... 167 Hard Fault Status (HFAULTSTAT), offset 0xD2C .............................................................. 173 Memory Management Fault Address (MMADDR), offset 0xD34 ........................................ 174 Bus Fault Address (FAULTADDR), offset 0xD38 .............................................................. 175 MPU Type (MPUTYPE), offset 0xD90 ............................................................................. 176 MPU Control (MPUCTRL), offset 0xD94 .......................................................................... 177 MPU Region Number (MPUNUMBER), offset 0xD98 ....................................................... 179 MPU Region Base Address (MPUBASE), offset 0xD9C ................................................... 180 MPU Region Base Address Alias 1 (MPUBASE1), offset 0xDA4 ....................................... 180 MPU Region Base Address Alias 2 (MPUBASE2), offset 0xDAC ...................................... 180 MPU Region Base Address Alias 3 (MPUBASE3), offset 0xDB4 ....................................... 180 MPU Region Attribute and Size (MPUATTR), offset 0xDA0 ............................................... 182 MPU Region Attribute and Size Alias 1 (MPUATTR1), offset 0xDA8 .................................. 182 MPU Region Attribute and Size Alias 2 (MPUATTR2), offset 0xDB0 .................................. 182 MPU Region Attribute and Size Alias 3 (MPUATTR3), offset 0xDB8 .................................. 182 Coprocessor Access Control (CPAC), offset 0xD88 .......................................................... 185 Floating-Point Context Control (FPCC), offset 0xF34 ........................................................ 186 Floating-Point Context Address (FPCA), offset 0xF38 ...................................................... 188 Floating-Point Default Status Control (FPDSC), offset 0xF3C ........................................... 189 System Control ............................................................................................................................ 202 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Device Identification 0 (DID0), offset 0x000 ..................................................................... 226 Device Identification 1 (DID1), offset 0x004 ..................................................................... 228 Brown-Out Reset Control (PBORCTL), offset 0x030 ........................................................ 231 Raw Interrupt Status (RIS), offset 0x050 .......................................................................... 232 Interrupt Mask Control (IMC), offset 0x054 ...................................................................... 234 Masked Interrupt Status and Clear (MISC), offset 0x058 .................................................. 236 Reset Cause (RESC), offset 0x05C ................................................................................ 239 Run-Mode Clock Configuration (RCC), offset 0x060 ......................................................... 241 GPIO High-Performance Bus Control (GPIOHBCTL), offset 0x06C ................................... 245 Run-Mode Clock Configuration 2 (RCC2), offset 0x070 .................................................... 247 Main Oscillator Control (MOSCCTL), offset 0x07C ........................................................... 250 Deep Sleep Clock Configuration (DSLPCLKCFG), offset 0x144 ........................................ 251 System Properties (SYSPROP), offset 0x14C .................................................................. 253 Precision Internal Oscillator Calibration (PIOSCCAL), offset 0x150 ................................... 255 Precision Internal Oscillator Statistics (PIOSCSTAT), offset 0x154 .................................... 257 PLL Frequency 0 (PLLFREQ0), offset 0x160 ................................................................... 258 PLL Frequency 1 (PLLFREQ1), offset 0x164 ................................................................... 259 PLL Status (PLLSTAT), offset 0x168 ............................................................................... 260 Sleep Power Configuration (SLPPWRCFG), offset 0x188 ................................................. 261 Deep-Sleep Power Configuration (DSLPPWRCFG), offset 0x18C ..................................... 263 LDO Sleep Power Control (LDOSPCTL), offset 0x1B4 ..................................................... 265 LDO Sleep Power Calibration (LDOSPCAL), offset 0x1B8 ................................................ 267 20 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 31: Register 32: Register 33: Register 34: Register 35: Register 36: Register 37: Register 38: Register 39: Register 40: Register 41: Register 42: Register 43: Register 44: Register 45: Register 46: Register 47: Register 48: Register 49: Register 50: Register 51: Register 52: Register 53: Register 54: Register 55: Register 56: Register 57: Register 58: Register 59: Register 60: Register 61: Register 62: Register 63: Register 64: Register 65: LDO Deep-Sleep Power Control (LDODPCTL), offset 0x1BC ........................................... 268 LDO Deep-Sleep Power Calibration (LDODPCAL), offset 0x1C0 ...................................... 270 Sleep / Deep-Sleep Power Mode Status (SDPMST), offset 0x1CC .................................... 271 Watchdog Timer Peripheral Present (PPWD), offset 0x300 ............................................... 274 16/32-Bit General-Purpose Timer Peripheral Present (PPTIMER), offset 0x304 ................. 275 General-Purpose Input/Output Peripheral Present (PPGPIO), offset 0x308 ........................ 277 Micro Direct Memory Access Peripheral Present (PPDMA), offset 0x30C .......................... 280 Hibernation Peripheral Present (PPHIB), offset 0x314 ...................................................... 281 Universal Asynchronous Receiver/Transmitter Peripheral Present (PPUART), offset 0x318 ........................................................................................................................... 282 Synchronous Serial Interface Peripheral Present (PPSSI), offset 0x31C ............................ 284 Inter-Integrated Circuit Peripheral Present (PPI2C), offset 0x320 ...................................... 286 Universal Serial Bus Peripheral Present (PPUSB), offset 0x328 ........................................ 288 Controller Area Network Peripheral Present (PPCAN), offset 0x334 .................................. 289 Analog-to-Digital Converter Peripheral Present (PPADC), offset 0x338 ............................. 290 Analog Comparator Peripheral Present (PPACMP), offset 0x33C ...................................... 291 Pulse Width Modulator Peripheral Present (PPPWM), offset 0x340 ................................... 292 Quadrature Encoder Interface Peripheral Present (PPQEI), offset 0x344 ........................... 293 EEPROM Peripheral Present (PPEEPROM), offset 0x358 ................................................ 294 32/64-Bit Wide General-Purpose Timer Peripheral Present (PPWTIMER), offset 0x35C ..... 295 Watchdog Timer Software Reset (SRWD), offset 0x500 ................................................... 297 16/32-Bit General-Purpose Timer Software Reset (SRTIMER), offset 0x504 ...................... 299 General-Purpose Input/Output Software Reset (SRGPIO), offset 0x508 ............................ 301 Micro Direct Memory Access Software Reset (SRDMA), offset 0x50C ............................... 303 Hibernation Software Reset (SRHIB), offset 0x514 ........................................................... 304 Universal Asynchronous Receiver/Transmitter Software Reset (SRUART), offset 0x518 .... 305 Synchronous Serial Interface Software Reset (SRSSI), offset 0x51C ................................ 307 Inter-Integrated Circuit Software Reset (SRI2C), offset 0x520 ........................................... 309 Controller Area Network Software Reset (SRCAN), offset 0x534 ....................................... 311 Analog-to-Digital Converter Software Reset (SRADC), offset 0x538 .................................. 312 Analog Comparator Software Reset (SRACMP), offset 0x53C .......................................... 314 EEPROM Software Reset (SREEPROM), offset 0x558 .................................................... 315 32/64-Bit Wide General-Purpose Timer Software Reset (SRWTIMER), offset 0x55C .......... 316 Watchdog Timer Run Mode Clock Gating Control (RCGCWD), offset 0x600 ...................... 318 16/32-Bit General-Purpose Timer Run Mode Clock Gating Control (RCGCTIMER), offset 0x604 ........................................................................................................................... 319 General-Purpose Input/Output Run Mode Clock Gating Control (RCGCGPIO), offset 0x608 ........................................................................................................................... 321 Micro Direct Memory Access Run Mode Clock Gating Control (RCGCDMA), offset 0x60C ........................................................................................................................... 323 Hibernation Run Mode Clock Gating Control (RCGCHIB), offset 0x614 ............................. 324 Universal Asynchronous Receiver/Transmitter Run Mode Clock Gating Control (RCGCUART), offset 0x618 .................................................................................................................. 325 Synchronous Serial Interface Run Mode Clock Gating Control (RCGCSSI), offset 0x61C ........................................................................................................................... 327 Inter-Integrated Circuit Run Mode Clock Gating Control (RCGCI2C), offset 0x620 ............. 329 Controller Area Network Run Mode Clock Gating Control (RCGCCAN), offset 0x634 ......... 331 Analog-to-Digital Converter Run Mode Clock Gating Control (RCGCADC), offset 0x638 .... 332 Analog Comparator Run Mode Clock Gating Control (RCGCACMP), offset 0x63C ............. 333 June 12, 2014 21 Texas Instruments-Production Data Table of Contents Register 66: Register 67: Register 68: Register 69: Register 70: Register 71: Register 72: Register 73: Register 74: Register 75: Register 76: Register 77: Register 78: Register 79: Register 80: Register 81: Register 82: Register 83: Register 84: Register 85: Register 86: Register 87: Register 88: Register 89: Register 90: Register 91: Register 92: Register 93: Register 94: Register 95: Register 96: Register 97: EEPROM Run Mode Clock Gating Control (RCGCEEPROM), offset 0x658 ....................... 334 32/64-Bit Wide General-Purpose Timer Run Mode Clock Gating Control (RCGCWTIMER), offset 0x65C .................................................................................................................. 335 Watchdog Timer Sleep Mode Clock Gating Control (SCGCWD), offset 0x700 .................... 337 16/32-Bit General-Purpose Timer Sleep Mode Clock Gating Control (SCGCTIMER), offset 0x704 ........................................................................................................................... 338 General-Purpose Input/Output Sleep Mode Clock Gating Control (SCGCGPIO), offset 0x708 ........................................................................................................................... 340 Micro Direct Memory Access Sleep Mode Clock Gating Control (SCGCDMA), offset 0x70C ........................................................................................................................... 342 Hibernation Sleep Mode Clock Gating Control (SCGCHIB), offset 0x714 ........................... 343 Universal Asynchronous Receiver/Transmitter Sleep Mode Clock Gating Control (SCGCUART), offset 0x718 ............................................................................................ 344 Synchronous Serial Interface Sleep Mode Clock Gating Control (SCGCSSI), offset 0x71C ........................................................................................................................... 346 Inter-Integrated Circuit Sleep Mode Clock Gating Control (SCGCI2C), offset 0x720 ........... 348 Controller Area Network Sleep Mode Clock Gating Control (SCGCCAN), offset 0x734 ....... 350 Analog-to-Digital Converter Sleep Mode Clock Gating Control (SCGCADC), offset 0x738 ........................................................................................................................... 351 Analog Comparator Sleep Mode Clock Gating Control (SCGCACMP), offset 0x73C .......... 352 EEPROM Sleep Mode Clock Gating Control (SCGCEEPROM), offset 0x758 ..................... 353 32/64-Bit Wide General-Purpose Timer Sleep Mode Clock Gating Control (SCGCWTIMER), offset 0x75C .................................................................................................................. 354 Watchdog Timer Deep-Sleep Mode Clock Gating Control (DCGCWD), offset 0x800 .......... 356 16/32-Bit General-Purpose Timer Deep-Sleep Mode Clock Gating Control (DCGCTIMER), offset 0x804 .................................................................................................................. 357 General-Purpose Input/Output Deep-Sleep Mode Clock Gating Control (DCGCGPIO), offset 0x808 ........................................................................................................................... 359 Micro Direct Memory Access Deep-Sleep Mode Clock Gating Control (DCGCDMA), offset 0x80C ........................................................................................................................... 361 Hibernation Deep-Sleep Mode Clock Gating Control (DCGCHIB), offset 0x814 .................. 362 Universal Asynchronous Receiver/Transmitter Deep-Sleep Mode Clock Gating Control (DCGCUART), offset 0x818 ............................................................................................ 363 Synchronous Serial Interface Deep-Sleep Mode Clock Gating Control (DCGCSSI), offset 0x81C ........................................................................................................................... 365 Inter-Integrated Circuit Deep-Sleep Mode Clock Gating Control (DCGCI2C), offset 0x820 ........................................................................................................................... 367 Controller Area Network Deep-Sleep Mode Clock Gating Control (DCGCCAN), offset 0x834 ........................................................................................................................... 369 Analog-to-Digital Converter Deep-Sleep Mode Clock Gating Control (DCGCADC), offset 0x838 ........................................................................................................................... 370 Analog Comparator Deep-Sleep Mode Clock Gating Control (DCGCACMP), offset 0x83C ........................................................................................................................... 371 EEPROM Deep-Sleep Mode Clock Gating Control (DCGCEEPROM), offset 0x858 ........... 372 32/64-Bit Wide General-Purpose Timer Deep-Sleep Mode Clock Gating Control (DCGCWTIMER), offset 0x85C ...................................................................................... 373 Watchdog Timer Peripheral Ready (PRWD), offset 0xA00 ................................................ 375 16/32-Bit General-Purpose Timer Peripheral Ready (PRTIMER), offset 0xA04 ................... 376 General-Purpose Input/Output Peripheral Ready (PRGPIO), offset 0xA08 ......................... 378 Micro Direct Memory Access Peripheral Ready (PRDMA), offset 0xA0C ........................... 380 22 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 98: Register 99: Register 100: Register 101: Register 102: Register 103: Register 104: Register 105: Register 106: Register 107: Register 108: Register 109: Register 110: Register 111: Register 112: Register 113: Register 114: Register 115: Register 116: Register 117: Register 118: Register 119: Register 120: Register 121: Register 122: Register 123: Register 124: Register 125: Register 126: Register 127: Register 128: Register 129: Hibernation Peripheral Ready (PRHIB), offset 0xA14 ....................................................... 381 Universal Asynchronous Receiver/Transmitter Peripheral Ready (PRUART), offset 0xA18 ........................................................................................................................... 382 Synchronous Serial Interface Peripheral Ready (PRSSI), offset 0xA1C ............................. 384 Inter-Integrated Circuit Peripheral Ready (PRI2C), offset 0xA20 ....................................... 386 Controller Area Network Peripheral Ready (PRCAN), offset 0xA34 ................................... 388 Analog-to-Digital Converter Peripheral Ready (PRADC), offset 0xA38 ............................... 389 Analog Comparator Peripheral Ready (PRACMP), offset 0xA3C ....................................... 390 EEPROM Peripheral Ready (PREEPROM), offset 0xA58 ................................................. 391 32/64-Bit Wide General-Purpose Timer Peripheral Ready (PRWTIMER), offset 0xA5C ...... 392 Device Capabilities 0 (DC0), offset 0x008 ........................................................................ 394 Device Capabilities 1 (DC1), offset 0x010 ........................................................................ 396 Device Capabilities 2 (DC2), offset 0x014 ........................................................................ 399 Device Capabilities 3 (DC3), offset 0x018 ........................................................................ 402 Device Capabilities 4 (DC4), offset 0x01C ....................................................................... 406 Device Capabilities 5 (DC5), offset 0x020 ........................................................................ 409 Device Capabilities 6 (DC6), offset 0x024 ........................................................................ 411 Device Capabilities 7 (DC7), offset 0x028 ........................................................................ 412 Device Capabilities 8 (DC8), offset 0x02C ....................................................................... 415 Software Reset Control 0 (SRCR0), offset 0x040 ............................................................. 418 Software Reset Control 1 (SRCR1), offset 0x044 ............................................................. 420 Software Reset Control 2 (SRCR2), offset 0x048 ............................................................. 423 Run Mode Clock Gating Control Register 0 (RCGC0), offset 0x100 ................................... 425 Run Mode Clock Gating Control Register 1 (RCGC1), offset 0x104 ................................... 428 Run Mode Clock Gating Control Register 2 (RCGC2), offset 0x108 ................................... 431 Sleep Mode Clock Gating Control Register 0 (SCGC0), offset 0x110 ................................. 433 Sleep Mode Clock Gating Control Register 1 (SCGC1), offset 0x114 ................................. 435 Sleep Mode Clock Gating Control Register 2 (SCGC2), offset 0x118 ................................. 438 Deep Sleep Mode Clock Gating Control Register 0 (DCGC0), offset 0x120 ....................... 440 Deep-Sleep Mode Clock Gating Control Register 1 (DCGC1), offset 0x124 ....................... 442 Deep Sleep Mode Clock Gating Control Register 2 (DCGC2), offset 0x128 ....................... 445 Device Capabilities 9 (DC9), offset 0x190 ........................................................................ 447 Non-Volatile Memory Information (NVMSTAT), offset 0x1A0 ............................................. 449 System Exception Module .......................................................................................................... 450 Register 1: Register 2: Register 3: Register 4: System Exception Raw Interrupt Status (SYSEXCRIS), offset 0x000 ................................ System Exception Interrupt Mask (SYSEXCIM), offset 0x004 ........................................... System Exception Masked Interrupt Status (SYSEXCMIS), offset 0x008 ........................... System Exception Interrupt Clear (SYSEXCIC), offset 0x00C ........................................... 451 453 455 457 Hibernation Module ..................................................................................................................... 458 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Hibernation RTC Counter (HIBRTCC), offset 0x000 ......................................................... Hibernation RTC Match 0 (HIBRTCM0), offset 0x004 ....................................................... Hibernation RTC Load (HIBRTCLD), offset 0x00C ........................................................... Hibernation Control (HIBCTL), offset 0x010 ..................................................................... Hibernation Interrupt Mask (HIBIM), offset 0x014 ............................................................. Hibernation Raw Interrupt Status (HIBRIS), offset 0x018 .................................................. Hibernation Masked Interrupt Status (HIBMIS), offset 0x01C ............................................ Hibernation Interrupt Clear (HIBIC), offset 0x020 ............................................................. Hibernation RTC Trim (HIBRTCT), offset 0x024 ............................................................... June 12, 2014 472 473 474 475 479 481 483 485 486 23 Texas Instruments-Production Data Table of Contents Register 10: Register 11: Hibernation RTC Sub Seconds (HIBRTCSS), offset 0x028 ............................................... 487 Hibernation Data (HIBDATA), offset 0x030-0x06F ............................................................ 488 Internal Memory ........................................................................................................................... 489 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 31: Register 32: Register 33: Register 34: Register 35: Register 36: Register 37: Register 38: Register 39: Register 40: Register 41: Register 42: Flash Memory Address (FMA), offset 0x000 .................................................................... 507 Flash Memory Data (FMD), offset 0x004 ......................................................................... 508 Flash Memory Control (FMC), offset 0x008 ..................................................................... 509 Flash Controller Raw Interrupt Status (FCRIS), offset 0x00C ............................................ 511 Flash Controller Interrupt Mask (FCIM), offset 0x010 ........................................................ 514 Flash Controller Masked Interrupt Status and Clear (FCMISC), offset 0x014 ..................... 516 Flash Memory Control 2 (FMC2), offset 0x020 ................................................................. 519 Flash Write Buffer Valid (FWBVAL), offset 0x030 ............................................................. 520 Flash Write Buffer n (FWBn), offset 0x100 - 0x17C .......................................................... 521 Flash Size (FSIZE), offset 0xFC0 .................................................................................... 522 SRAM Size (SSIZE), offset 0xFC4 .................................................................................. 523 ROM Software Map (ROMSWMAP), offset 0xFCC ........................................................... 524 EEPROM Size Information (EESIZE), offset 0x000 .......................................................... 525 EEPROM Current Block (EEBLOCK), offset 0x004 .......................................................... 526 EEPROM Current Offset (EEOFFSET), offset 0x008 ........................................................ 527 EEPROM Read-Write (EERDWR), offset 0x010 .............................................................. 528 EEPROM Read-Write with Increment (EERDWRINC), offset 0x014 .................................. 529 EEPROM Done Status (EEDONE), offset 0x018 .............................................................. 530 EEPROM Support Control and Status (EESUPP), offset 0x01C ........................................ 532 EEPROM Unlock (EEUNLOCK), offset 0x020 .................................................................. 534 EEPROM Protection (EEPROT), offset 0x030 ................................................................. 535 EEPROM Password (EEPASS0), offset 0x034 ................................................................. 537 EEPROM Password (EEPASS1), offset 0x038 ................................................................. 537 EEPROM Password (EEPASS2), offset 0x03C ................................................................ 537 EEPROM Interrupt (EEINT), offset 0x040 ........................................................................ 538 EEPROM Block Hide (EEHIDE), offset 0x050 .................................................................. 539 EEPROM Debug Mass Erase (EEDBGME), offset 0x080 ................................................. 540 EEPROM Peripheral Properties (EEPROMPP), offset 0xFC0 ........................................... 541 ROM Control (RMCTL), offset 0x0F0 .............................................................................. 542 Flash Memory Protection Read Enable 0 (FMPRE0), offset 0x130 and 0x200 ................... 543 Flash Memory Protection Read Enable 1 (FMPRE1), offset 0x204 .................................... 543 Flash Memory Protection Read Enable 2 (FMPRE2), offset 0x208 .................................... 543 Flash Memory Protection Read Enable 3 (FMPRE3), offset 0x20C ................................... 543 Flash Memory Protection Program Enable 0 (FMPPE0), offset 0x134 and 0x400 ............... 544 Flash Memory Protection Program Enable 1 (FMPPE1), offset 0x404 ............................... 544 Flash Memory Protection Program Enable 2 (FMPPE2), offset 0x408 ............................... 544 Flash Memory Protection Program Enable 3 (FMPPE3), offset 0x40C ............................... 544 Boot Configuration (BOOTCFG), offset 0x1D0 ................................................................. 546 User Register 0 (USER_REG0), offset 0x1E0 .................................................................. 549 User Register 1 (USER_REG1), offset 0x1E4 .................................................................. 549 User Register 2 (USER_REG2), offset 0x1E8 .................................................................. 549 User Register 3 (USER_REG3), offset 0x1EC ................................................................. 549 Micro Direct Memory Access (μDMA) ........................................................................................ 550 Register 1: Register 2: DMA Channel Source Address End Pointer (DMASRCENDP), offset 0x000 ...................... 574 DMA Channel Destination Address End Pointer (DMADSTENDP), offset 0x004 ................ 575 24 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 31: Register 32: Register 33: Register 34: Register 35: DMA Channel Control Word (DMACHCTL), offset 0x008 .................................................. 576 DMA Status (DMASTAT), offset 0x000 ............................................................................ 581 DMA Configuration (DMACFG), offset 0x004 ................................................................... 583 DMA Channel Control Base Pointer (DMACTLBASE), offset 0x008 .................................. 584 DMA Alternate Channel Control Base Pointer (DMAALTBASE), offset 0x00C .................... 585 DMA Channel Wait-on-Request Status (DMAWAITSTAT), offset 0x010 ............................. 586 DMA Channel Software Request (DMASWREQ), offset 0x014 ......................................... 587 DMA Channel Useburst Set (DMAUSEBURSTSET), offset 0x018 .................................... 588 DMA Channel Useburst Clear (DMAUSEBURSTCLR), offset 0x01C ................................. 589 DMA Channel Request Mask Set (DMAREQMASKSET), offset 0x020 .............................. 590 DMA Channel Request Mask Clear (DMAREQMASKCLR), offset 0x024 ........................... 591 DMA Channel Enable Set (DMAENASET), offset 0x028 ................................................... 592 DMA Channel Enable Clear (DMAENACLR), offset 0x02C ............................................... 593 DMA Channel Primary Alternate Set (DMAALTSET), offset 0x030 .................................... 594 DMA Channel Primary Alternate Clear (DMAALTCLR), offset 0x034 ................................. 595 DMA Channel Priority Set (DMAPRIOSET), offset 0x038 ................................................. 596 DMA Channel Priority Clear (DMAPRIOCLR), offset 0x03C .............................................. 597 DMA Bus Error Clear (DMAERRCLR), offset 0x04C ........................................................ 598 DMA Channel Assignment (DMACHASGN), offset 0x500 ................................................. 599 DMA Channel Interrupt Status (DMACHIS), offset 0x504 .................................................. 600 DMA Channel Map Select 0 (DMACHMAP0), offset 0x510 ............................................... 601 DMA Channel Map Select 1 (DMACHMAP1), offset 0x514 ............................................... 602 DMA Channel Map Select 2 (DMACHMAP2), offset 0x518 ............................................... 603 DMA Channel Map Select 3 (DMACHMAP3), offset 0x51C .............................................. 604 DMA Peripheral Identification 0 (DMAPeriphID0), offset 0xFE0 ......................................... 605 DMA Peripheral Identification 1 (DMAPeriphID1), offset 0xFE4 ......................................... 606 DMA Peripheral Identification 2 (DMAPeriphID2), offset 0xFE8 ......................................... 607 DMA Peripheral Identification 3 (DMAPeriphID3), offset 0xFEC ........................................ 608 DMA Peripheral Identification 4 (DMAPeriphID4), offset 0xFD0 ......................................... 609 DMA PrimeCell Identification 0 (DMAPCellID0), offset 0xFF0 ........................................... 610 DMA PrimeCell Identification 1 (DMAPCellID1), offset 0xFF4 ........................................... 611 DMA PrimeCell Identification 2 (DMAPCellID2), offset 0xFF8 ........................................... 612 DMA PrimeCell Identification 3 (DMAPCellID3), offset 0xFFC ........................................... 613 General-Purpose Input/Outputs (GPIOs) ................................................................................... 614 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: GPIO Data (GPIODATA), offset 0x000 ............................................................................ 627 GPIO Direction (GPIODIR), offset 0x400 ......................................................................... 628 GPIO Interrupt Sense (GPIOIS), offset 0x404 .................................................................. 629 GPIO Interrupt Both Edges (GPIOIBE), offset 0x408 ........................................................ 630 GPIO Interrupt Event (GPIOIEV), offset 0x40C ................................................................ 631 GPIO Interrupt Mask (GPIOIM), offset 0x410 ................................................................... 632 GPIO Raw Interrupt Status (GPIORIS), offset 0x414 ........................................................ 633 GPIO Masked Interrupt Status (GPIOMIS), offset 0x418 ................................................... 634 GPIO Interrupt Clear (GPIOICR), offset 0x41C ................................................................ 635 GPIO Alternate Function Select (GPIOAFSEL), offset 0x420 ............................................ 636 GPIO 2-mA Drive Select (GPIODR2R), offset 0x500 ........................................................ 638 GPIO 4-mA Drive Select (GPIODR4R), offset 0x504 ........................................................ 639 GPIO 8-mA Drive Select (GPIODR8R), offset 0x508 ........................................................ 640 GPIO Open Drain Select (GPIOODR), offset 0x50C ......................................................... 641 June 12, 2014 25 Texas Instruments-Production Data Table of Contents Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 31: Register 32: Register 33: Register 34: Register 35: Register 36: GPIO Pull-Up Select (GPIOPUR), offset 0x510 ................................................................ 642 GPIO Pull-Down Select (GPIOPDR), offset 0x514 ........................................................... 644 GPIO Slew Rate Control Select (GPIOSLR), offset 0x518 ................................................ 646 GPIO Digital Enable (GPIODEN), offset 0x51C ................................................................ 647 GPIO Lock (GPIOLOCK), offset 0x520 ............................................................................ 649 GPIO Commit (GPIOCR), offset 0x524 ............................................................................ 650 GPIO Analog Mode Select (GPIOAMSEL), offset 0x528 ................................................... 652 GPIO Port Control (GPIOPCTL), offset 0x52C ................................................................. 653 GPIO ADC Control (GPIOADCCTL), offset 0x530 ............................................................ 655 GPIO DMA Control (GPIODMACTL), offset 0x534 ........................................................... 656 GPIO Peripheral Identification 4 (GPIOPeriphID4), offset 0xFD0 ....................................... 657 GPIO Peripheral Identification 5 (GPIOPeriphID5), offset 0xFD4 ....................................... 658 GPIO Peripheral Identification 6 (GPIOPeriphID6), offset 0xFD8 ....................................... 659 GPIO Peripheral Identification 7 (GPIOPeriphID7), offset 0xFDC ...................................... 660 GPIO Peripheral Identification 0 (GPIOPeriphID0), offset 0xFE0 ....................................... 661 GPIO Peripheral Identification 1 (GPIOPeriphID1), offset 0xFE4 ....................................... 662 GPIO Peripheral Identification 2 (GPIOPeriphID2), offset 0xFE8 ....................................... 663 GPIO Peripheral Identification 3 (GPIOPeriphID3), offset 0xFEC ...................................... 664 GPIO PrimeCell Identification 0 (GPIOPCellID0), offset 0xFF0 .......................................... 665 GPIO PrimeCell Identification 1 (GPIOPCellID1), offset 0xFF4 .......................................... 666 GPIO PrimeCell Identification 2 (GPIOPCellID2), offset 0xFF8 .......................................... 667 GPIO PrimeCell Identification 3 (GPIOPCellID3), offset 0xFFC ......................................... 668 General-Purpose Timers ............................................................................................................. 669 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: GPTM Configuration (GPTMCFG), offset 0x000 .............................................................. 692 GPTM Timer A Mode (GPTMTAMR), offset 0x004 ........................................................... 694 GPTM Timer B Mode (GPTMTBMR), offset 0x008 ........................................................... 698 GPTM Control (GPTMCTL), offset 0x00C ........................................................................ 702 GPTM Synchronize (GPTMSYNC), offset 0x010 .............................................................. 706 GPTM Interrupt Mask (GPTMIMR), offset 0x018 .............................................................. 710 GPTM Raw Interrupt Status (GPTMRIS), offset 0x01C ..................................................... 713 GPTM Masked Interrupt Status (GPTMMIS), offset 0x020 ................................................ 716 GPTM Interrupt Clear (GPTMICR), offset 0x024 .............................................................. 719 GPTM Timer A Interval Load (GPTMTAILR), offset 0x028 ................................................ 721 GPTM Timer B Interval Load (GPTMTBILR), offset 0x02C ................................................ 722 GPTM Timer A Match (GPTMTAMATCHR), offset 0x030 .................................................. 723 GPTM Timer B Match (GPTMTBMATCHR), offset 0x034 ................................................. 724 GPTM Timer A Prescale (GPTMTAPR), offset 0x038 ....................................................... 725 GPTM Timer B Prescale (GPTMTBPR), offset 0x03C ...................................................... 726 GPTM TimerA Prescale Match (GPTMTAPMR), offset 0x040 ........................................... 727 GPTM TimerB Prescale Match (GPTMTBPMR), offset 0x044 ........................................... 728 GPTM Timer A (GPTMTAR), offset 0x048 ....................................................................... 729 GPTM Timer B (GPTMTBR), offset 0x04C ....................................................................... 730 GPTM Timer A Value (GPTMTAV), offset 0x050 ............................................................... 731 GPTM Timer B Value (GPTMTBV), offset 0x054 .............................................................. 732 GPTM RTC Predivide (GPTMRTCPD), offset 0x058 ........................................................ 733 GPTM Timer A Prescale Snapshot (GPTMTAPS), offset 0x05C ........................................ 734 GPTM Timer B Prescale Snapshot (GPTMTBPS), offset 0x060 ........................................ 735 GPTM Timer A Prescale Value (GPTMTAPV), offset 0x064 .............................................. 736 26 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 26: Register 27: GPTM Timer B Prescale Value (GPTMTBPV), offset 0x068 .............................................. 737 GPTM Peripheral Properties (GPTMPP), offset 0xFC0 ..................................................... 738 Watchdog Timers ......................................................................................................................... 739 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Watchdog Load (WDTLOAD), offset 0x000 ...................................................................... 743 Watchdog Value (WDTVALUE), offset 0x004 ................................................................... 744 Watchdog Control (WDTCTL), offset 0x008 ..................................................................... 745 Watchdog Interrupt Clear (WDTICR), offset 0x00C .......................................................... 747 Watchdog Raw Interrupt Status (WDTRIS), offset 0x010 .................................................. 748 Watchdog Masked Interrupt Status (WDTMIS), offset 0x014 ............................................. 749 Watchdog Test (WDTTEST), offset 0x418 ....................................................................... 750 Watchdog Lock (WDTLOCK), offset 0xC00 ..................................................................... 751 Watchdog Peripheral Identification 4 (WDTPeriphID4), offset 0xFD0 ................................. 752 Watchdog Peripheral Identification 5 (WDTPeriphID5), offset 0xFD4 ................................. 753 Watchdog Peripheral Identification 6 (WDTPeriphID6), offset 0xFD8 ................................. 754 Watchdog Peripheral Identification 7 (WDTPeriphID7), offset 0xFDC ................................ 755 Watchdog Peripheral Identification 0 (WDTPeriphID0), offset 0xFE0 ................................. 756 Watchdog Peripheral Identification 1 (WDTPeriphID1), offset 0xFE4 ................................. 757 Watchdog Peripheral Identification 2 (WDTPeriphID2), offset 0xFE8 ................................. 758 Watchdog Peripheral Identification 3 (WDTPeriphID3), offset 0xFEC ................................. 759 Watchdog PrimeCell Identification 0 (WDTPCellID0), offset 0xFF0 .................................... 760 Watchdog PrimeCell Identification 1 (WDTPCellID1), offset 0xFF4 .................................... 761 Watchdog PrimeCell Identification 2 (WDTPCellID2), offset 0xFF8 .................................... 762 Watchdog PrimeCell Identification 3 (WDTPCellID3 ), offset 0xFFC .................................. 763 Analog-to-Digital Converter (ADC) ............................................................................................. 764 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: ADC Active Sample Sequencer (ADCACTSS), offset 0x000 ............................................. 786 ADC Raw Interrupt Status (ADCRIS), offset 0x004 ........................................................... 788 ADC Interrupt Mask (ADCIM), offset 0x008 ..................................................................... 790 ADC Interrupt Status and Clear (ADCISC), offset 0x00C .................................................. 793 ADC Overflow Status (ADCOSTAT), offset 0x010 ............................................................ 796 ADC Event Multiplexer Select (ADCEMUX), offset 0x014 ................................................. 798 ADC Underflow Status (ADCUSTAT), offset 0x018 ........................................................... 803 ADC Sample Sequencer Priority (ADCSSPRI), offset 0x020 ............................................. 804 ADC Sample Phase Control (ADCSPC), offset 0x024 ...................................................... 806 ADC Processor Sample Sequence Initiate (ADCPSSI), offset 0x028 ................................. 808 ADC Sample Averaging Control (ADCSAC), offset 0x030 ................................................. 810 ADC Digital Comparator Interrupt Status and Clear (ADCDCISC), offset 0x034 ................. 811 ADC Control (ADCCTL), offset 0x038 ............................................................................. 813 ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0), offset 0x040 ............... 814 ADC Sample Sequence Control 0 (ADCSSCTL0), offset 0x044 ........................................ 816 ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0), offset 0x048 ................................ 823 ADC Sample Sequence Result FIFO 1 (ADCSSFIFO1), offset 0x068 ................................ 823 ADC Sample Sequence Result FIFO 2 (ADCSSFIFO2), offset 0x088 ................................ 823 ADC Sample Sequence Result FIFO 3 (ADCSSFIFO3), offset 0x0A8 ............................... 823 ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0), offset 0x04C ............................. 824 ADC Sample Sequence FIFO 1 Status (ADCSSFSTAT1), offset 0x06C ............................. 824 ADC Sample Sequence FIFO 2 Status (ADCSSFSTAT2), offset 0x08C ............................ 824 ADC Sample Sequence FIFO 3 Status (ADCSSFSTAT3), offset 0x0AC ............................ 824 ADC Sample Sequence 0 Operation (ADCSSOP0), offset 0x050 ...................................... 826 June 12, 2014 27 Texas Instruments-Production Data Table of Contents Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 31: Register 32: Register 33: Register 34: Register 35: Register 36: Register 37: Register 38: Register 39: Register 40: Register 41: Register 42: Register 43: Register 44: Register 45: Register 46: Register 47: Register 48: Register 49: Register 50: Register 51: Register 52: Register 53: Register 54: Register 55: Register 56: Register 57: ADC Sample Sequence 0 Digital Comparator Select (ADCSSDC0), offset 0x054 .............. 828 ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1), offset 0x060 ............... 830 ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2), offset 0x080 ............... 830 ADC Sample Sequence Control 1 (ADCSSCTL1), offset 0x064 ........................................ 831 ADC Sample Sequence Control 2 (ADCSSCTL2), offset 0x084 ........................................ 831 ADC Sample Sequence 1 Operation (ADCSSOP1), offset 0x070 ...................................... 835 ADC Sample Sequence 2 Operation (ADCSSOP2), offset 0x090 ..................................... 835 ADC Sample Sequence 1 Digital Comparator Select (ADCSSDC1), offset 0x074 .............. 836 ADC Sample Sequence 2 Digital Comparator Select (ADCSSDC2), offset 0x094 .............. 836 ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3), offset 0x0A0 ............... 838 ADC Sample Sequence Control 3 (ADCSSCTL3), offset 0x0A4 ........................................ 839 ADC Sample Sequence 3 Operation (ADCSSOP3), offset 0x0B0 ..................................... 841 ADC Sample Sequence 3 Digital Comparator Select (ADCSSDC3), offset 0x0B4 .............. 842 ADC Digital Comparator Reset Initial Conditions (ADCDCRIC), offset 0xD00 ..................... 843 ADC Digital Comparator Control 0 (ADCDCCTL0), offset 0xE00 ....................................... 848 ADC Digital Comparator Control 1 (ADCDCCTL1), offset 0xE04 ....................................... 848 ADC Digital Comparator Control 2 (ADCDCCTL2), offset 0xE08 ....................................... 848 ADC Digital Comparator Control 3 (ADCDCCTL3), offset 0xE0C ...................................... 848 ADC Digital Comparator Control 4 (ADCDCCTL4), offset 0xE10 ....................................... 848 ADC Digital Comparator Control 5 (ADCDCCTL5), offset 0xE14 ....................................... 848 ADC Digital Comparator Control 6 (ADCDCCTL6), offset 0xE18 ....................................... 848 ADC Digital Comparator Control 7 (ADCDCCTL7), offset 0xE1C ...................................... 848 ADC Digital Comparator Range 0 (ADCDCCMP0), offset 0xE40 ....................................... 850 ADC Digital Comparator Range 1 (ADCDCCMP1), offset 0xE44 ....................................... 850 ADC Digital Comparator Range 2 (ADCDCCMP2), offset 0xE48 ....................................... 850 ADC Digital Comparator Range 3 (ADCDCCMP3), offset 0xE4C ...................................... 850 ADC Digital Comparator Range 4 (ADCDCCMP4), offset 0xE50 ....................................... 850 ADC Digital Comparator Range 5 (ADCDCCMP5), offset 0xE54 ....................................... 850 ADC Digital Comparator Range 6 (ADCDCCMP6), offset 0xE58 ....................................... 850 ADC Digital Comparator Range 7 (ADCDCCMP7), offset 0xE5C ...................................... 850 ADC Peripheral Properties (ADCPP), offset 0xFC0 .......................................................... 851 ADC Peripheral Configuration (ADCPC), offset 0xFC4 ..................................................... 853 ADC Clock Configuration (ADCCC), offset 0xFC8 ............................................................ 854 Universal Asynchronous Receivers/Transmitters (UARTs) ..................................................... 855 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: UART Data (UARTDR), offset 0x000 ............................................................................... 868 UART Receive Status/Error Clear (UARTRSR/UARTECR), offset 0x004 ........................... 870 UART Flag (UARTFR), offset 0x018 ................................................................................ 873 UART IrDA Low-Power Register (UARTILPR), offset 0x020 ............................................. 875 UART Integer Baud-Rate Divisor (UARTIBRD), offset 0x024 ............................................ 876 UART Fractional Baud-Rate Divisor (UARTFBRD), offset 0x028 ....................................... 877 UART Line Control (UARTLCRH), offset 0x02C ............................................................... 878 UART Control (UARTCTL), offset 0x030 ......................................................................... 880 UART Interrupt FIFO Level Select (UARTIFLS), offset 0x034 ........................................... 884 UART Interrupt Mask (UARTIM), offset 0x038 ................................................................. 886 UART Raw Interrupt Status (UARTRIS), offset 0x03C ...................................................... 889 UART Masked Interrupt Status (UARTMIS), offset 0x040 ................................................. 892 UART Interrupt Clear (UARTICR), offset 0x044 ............................................................... 895 UART DMA Control (UARTDMACTL), offset 0x048 .......................................................... 897 28 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: UART 9-Bit Self Address (UART9BITADDR), offset 0x0A4 ............................................... 898 UART 9-Bit Self Address Mask (UART9BITAMASK), offset 0x0A8 .................................... 899 UART Peripheral Properties (UARTPP), offset 0xFC0 ...................................................... 900 UART Clock Configuration (UARTCC), offset 0xFC8 ........................................................ 901 UART Peripheral Identification 4 (UARTPeriphID4), offset 0xFD0 ..................................... 902 UART Peripheral Identification 5 (UARTPeriphID5), offset 0xFD4 ..................................... 903 UART Peripheral Identification 6 (UARTPeriphID6), offset 0xFD8 ..................................... 904 UART Peripheral Identification 7 (UARTPeriphID7), offset 0xFDC ..................................... 905 UART Peripheral Identification 0 (UARTPeriphID0), offset 0xFE0 ...................................... 906 UART Peripheral Identification 1 (UARTPeriphID1), offset 0xFE4 ...................................... 907 UART Peripheral Identification 2 (UARTPeriphID2), offset 0xFE8 ...................................... 908 UART Peripheral Identification 3 (UARTPeriphID3), offset 0xFEC ..................................... 909 UART PrimeCell Identification 0 (UARTPCellID0), offset 0xFF0 ........................................ 910 UART PrimeCell Identification 1 (UARTPCellID1), offset 0xFF4 ........................................ 911 UART PrimeCell Identification 2 (UARTPCellID2), offset 0xFF8 ........................................ 912 UART PrimeCell Identification 3 (UARTPCellID3), offset 0xFFC ........................................ 913 Synchronous Serial Interface (SSI) ............................................................................................ 914 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: SSI Control 0 (SSICR0), offset 0x000 .............................................................................. 931 SSI Control 1 (SSICR1), offset 0x004 .............................................................................. 933 SSI Data (SSIDR), offset 0x008 ...................................................................................... 935 SSI Status (SSISR), offset 0x00C ................................................................................... 936 SSI Clock Prescale (SSICPSR), offset 0x010 .................................................................. 938 SSI Interrupt Mask (SSIIM), offset 0x014 ......................................................................... 939 SSI Raw Interrupt Status (SSIRIS), offset 0x018 .............................................................. 940 SSI Masked Interrupt Status (SSIMIS), offset 0x01C ........................................................ 942 SSI Interrupt Clear (SSIICR), offset 0x020 ....................................................................... 944 SSI DMA Control (SSIDMACTL), offset 0x024 ................................................................. 945 SSI Clock Configuration (SSICC), offset 0xFC8 ............................................................... 946 SSI Peripheral Identification 4 (SSIPeriphID4), offset 0xFD0 ............................................. 947 SSI Peripheral Identification 5 (SSIPeriphID5), offset 0xFD4 ............................................. 948 SSI Peripheral Identification 6 (SSIPeriphID6), offset 0xFD8 ............................................. 949 SSI Peripheral Identification 7 (SSIPeriphID7), offset 0xFDC ............................................ 950 SSI Peripheral Identification 0 (SSIPeriphID0), offset 0xFE0 ............................................. 951 SSI Peripheral Identification 1 (SSIPeriphID1), offset 0xFE4 ............................................. 952 SSI Peripheral Identification 2 (SSIPeriphID2), offset 0xFE8 ............................................. 953 SSI Peripheral Identification 3 (SSIPeriphID3), offset 0xFEC ............................................ 954 SSI PrimeCell Identification 0 (SSIPCellID0), offset 0xFF0 ............................................... 955 SSI PrimeCell Identification 1 (SSIPCellID1), offset 0xFF4 ............................................... 956 SSI PrimeCell Identification 2 (SSIPCellID2), offset 0xFF8 ............................................... 957 SSI PrimeCell Identification 3 (SSIPCellID3), offset 0xFFC ............................................... 958 Inter-Integrated Circuit (I2C) Interface ........................................................................................ 959 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: I2C Master Slave Address (I2CMSA), offset 0x000 ........................................................... 981 I2C Master Control/Status (I2CMCS), offset 0x004 ........................................................... 982 I2C Master Data (I2CMDR), offset 0x008 ......................................................................... 987 I2C Master Timer Period (I2CMTPR), offset 0x00C ........................................................... 988 I2C Master Interrupt Mask (I2CMIMR), offset 0x010 ......................................................... 989 I2C Master Raw Interrupt Status (I2CMRIS), offset 0x014 ................................................. 990 June 12, 2014 29 Texas Instruments-Production Data Table of Contents Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: I2C Master Masked Interrupt Status (I2CMMIS), offset 0x018 ........................................... 991 I2C Master Interrupt Clear (I2CMICR), offset 0x01C ......................................................... 992 I2C Master Configuration (I2CMCR), offset 0x020 ............................................................ 993 I2C Master Clock Low Timeout Count (I2CMCLKOCNT), offset 0x024 ............................... 995 I2C Master Bus Monitor (I2CMBMON), offset 0x02C ........................................................ 996 I2C Master Configuration 2 (I2CMCR2), offset 0x038 ....................................................... 997 I2C Slave Own Address (I2CSOAR), offset 0x800 ............................................................ 998 I2C Slave Control/Status (I2CSCSR), offset 0x804 ........................................................... 999 I2C Slave Data (I2CSDR), offset 0x808 ......................................................................... 1001 I2C Slave Interrupt Mask (I2CSIMR), offset 0x80C ......................................................... 1002 I2C Slave Raw Interrupt Status (I2CSRIS), offset 0x810 ................................................. 1003 I2C Slave Masked Interrupt Status (I2CSMIS), offset 0x814 ............................................ 1004 I2C Slave Interrupt Clear (I2CSICR), offset 0x818 .......................................................... 1005 I2C Slave Own Address 2 (I2CSOAR2), offset 0x81C ..................................................... 1006 I2C Slave ACK Control (I2CSACKCTL), offset 0x820 ...................................................... 1007 I2C Peripheral Properties (I2CPP), offset 0xFC0 ............................................................ 1008 I2C Peripheral Configuration (I2CPC), offset 0xFC4 ....................................................... 1009 Controller Area Network (CAN) Module ................................................................................... 1010 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: CAN Control (CANCTL), offset 0x000 ............................................................................ 1031 CAN Status (CANSTS), offset 0x004 ............................................................................. 1033 CAN Error Counter (CANERR), offset 0x008 ................................................................. 1036 CAN Bit Timing (CANBIT), offset 0x00C ........................................................................ 1037 CAN Interrupt (CANINT), offset 0x010 ........................................................................... 1038 CAN Test (CANTST), offset 0x014 ................................................................................ 1039 CAN Baud Rate Prescaler Extension (CANBRPE), offset 0x018 ..................................... 1041 CAN IF1 Command Request (CANIF1CRQ), offset 0x020 .............................................. 1042 CAN IF2 Command Request (CANIF2CRQ), offset 0x080 .............................................. 1042 CAN IF1 Command Mask (CANIF1CMSK), offset 0x024 ................................................ 1043 CAN IF2 Command Mask (CANIF2CMSK), offset 0x084 ................................................ 1043 CAN IF1 Mask 1 (CANIF1MSK1), offset 0x028 .............................................................. 1046 CAN IF2 Mask 1 (CANIF2MSK1), offset 0x088 .............................................................. 1046 CAN IF1 Mask 2 (CANIF1MSK2), offset 0x02C .............................................................. 1047 CAN IF2 Mask 2 (CANIF2MSK2), offset 0x08C .............................................................. 1047 CAN IF1 Arbitration 1 (CANIF1ARB1), offset 0x030 ....................................................... 1049 CAN IF2 Arbitration 1 (CANIF2ARB1), offset 0x090 ....................................................... 1049 CAN IF1 Arbitration 2 (CANIF1ARB2), offset 0x034 ....................................................... 1050 CAN IF2 Arbitration 2 (CANIF2ARB2), offset 0x094 ....................................................... 1050 CAN IF1 Message Control (CANIF1MCTL), offset 0x038 ................................................ 1052 CAN IF2 Message Control (CANIF2MCTL), offset 0x098 ................................................ 1052 CAN IF1 Data A1 (CANIF1DA1), offset 0x03C ............................................................... 1055 CAN IF1 Data A2 (CANIF1DA2), offset 0x040 ................................................................ 1055 CAN IF1 Data B1 (CANIF1DB1), offset 0x044 ................................................................ 1055 CAN IF1 Data B2 (CANIF1DB2), offset 0x048 ................................................................ 1055 CAN IF2 Data A1 (CANIF2DA1), offset 0x09C ............................................................... 1055 CAN IF2 Data A2 (CANIF2DA2), offset 0x0A0 ............................................................... 1055 CAN IF2 Data B1 (CANIF2DB1), offset 0x0A4 ............................................................... 1055 CAN IF2 Data B2 (CANIF2DB2), offset 0x0A8 ............................................................... 1055 30 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 30: Register 31: Register 32: Register 33: Register 34: Register 35: Register 36: Register 37: CAN Transmission Request 1 (CANTXRQ1), offset 0x100 .............................................. CAN Transmission Request 2 (CANTXRQ2), offset 0x104 .............................................. CAN New Data 1 (CANNWDA1), offset 0x120 ............................................................... CAN New Data 2 (CANNWDA2), offset 0x124 ............................................................... CAN Message 1 Interrupt Pending (CANMSG1INT), offset 0x140 ................................... CAN Message 2 Interrupt Pending (CANMSG2INT), offset 0x144 ................................... CAN Message 1 Valid (CANMSG1VAL), offset 0x160 ..................................................... CAN Message 2 Valid (CANMSG2VAL), offset 0x164 ..................................................... 1056 1056 1057 1057 1058 1058 1059 1059 Analog Comparators ................................................................................................................. 1060 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Analog Comparator Masked Interrupt Status (ACMIS), offset 0x000 ................................ 1067 Analog Comparator Raw Interrupt Status (ACRIS), offset 0x004 ..................................... 1068 Analog Comparator Interrupt Enable (ACINTEN), offset 0x008 ....................................... 1069 Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x010 ..................... 1070 Analog Comparator Status 0 (ACSTAT0), offset 0x020 ................................................... 1071 Analog Comparator Status 1 (ACSTAT1), offset 0x040 ................................................... 1071 Analog Comparator Control 0 (ACCTL0), offset 0x024 ................................................... 1072 Analog Comparator Control 1 (ACCTL1), offset 0x044 ................................................... 1072 Analog Comparator Peripheral Properties (ACMPPP), offset 0xFC0 ................................ 1074 June 12, 2014 31 Texas Instruments-Production Data Revision History Revision History The revision history table notes changes made between the indicated revisions of the TM4C1231H6PM data sheet. Table 1. Revision History Date June 2014 March 2014 November 2013 Revision Description 15842.2741 ■ In System Control Chapter, corrected description for MINSYSDIV bitfield in Device Capabilities 1 (DC1) legacy register. ■ In Timers chapter, removed erroneous references to TCACT bit field. ■ In SSI chapter, corrected that during idle periods the transmit data line SSInTx is tristated. ■ In Package Information appendix: – Corrected Key to Part Numbers diagram. – Moved Orderable Part Numbers table to addendum. – Deleted Packaging Materials section and put into separate packaging document. ■ Additional minor data sheet clarifications and corrections. 15741.2722 ■ In the Internal Memory chapter, in the EEPROM section: – Added section on soft reset handling. – Added important information on EEPROM initialization and configuration. ■ In the DMA chapter, added information regarding interrupts and transfers from the UART or SSI modules. ■ In the Hibernation chapter, noted that the EXTW bit is set in the HIBRIS register regardless of the PINWEN setting in the HIBCTL register. ■ In the GPIO chapter: – Corrected table GPIO Pins with Special Considerations. – Added information on preventing false interrupts. – Corrected GPIOAMSEL register to be 8 bits. ■ In the Timer chapter: – Clarified initialization and configuration for Input-Edge Count mode. – Clarified behavior of TnMIE and TnCINTD bits in the GPTM Timer n Mode (GPTMTnMR) register. ■ In the Electrical Characteristics chapter: – In table Reset Characteristics, clarified internal reset time parameter values. – In table Hibernation Oscillator Input Characteristics, added parameter CINSE Input capacitance. – In tables Hibernation Oscillator Input Characteristics and Main Oscillator Input Characteristics, removed parameter C0 Crystal shunt capacitance. – Updated table Crystal Parameters. – In table GPIO Module Characteristics, added parameter CGPIO GPIO Digital Input Capacitance. – Added table PWM Timing Characteristics. ■ In the Package Information appendix: – Updated Orderable Devices section to reflect silicon revision 7 part numbers. – Added Tape and Reel pin 1 location. ■ Additional minor data sheet clarifications and corrections. 15553.2700 ■ ■ In System Control chapter, clarified PIOSC features and accuracy. In Hibernation Module chapter: 32 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 1. Revision History (continued) Date Revision Description Corrected figures "Using a Crystal as the Hibernation Clock Source with a Single Battery Source" and "Using a Regulator for Both VDD and VBAT". – Replaced RTC Trim tables with two new figures "Counter Behavior with a TRIM Value of 0x8002" and "Counter Behavior with a TRIM Value of 0x7FFC". – Clarified Hibernation Data (HIBDATA) register description. ■ In Watchdog Timers chapter, clarified Watchdog Control (WDTCTL) register description. ■ In ADC chapter: – Clarified functionality when using an ADC digital comparator as a fault source. – Clarified signals used for ADC voltage reference. – Corrected VREF bit in ADC Control (ADCCTL) register from 2-bit field [1:0] to 1-bit field [0]. ■ In UART chapter, clarified DMA operation. ■ In SSI chapter: ■ ■ ■ July 16, 2013 – 15033.2672 ■ – Corrected timing guidelines in figures "Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0" and "Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0". – Clarified SSI Initialization and Configuration. – Corrected bit 3 in SSI Control 1 (SSICR1) register from SOD (SSI Slave Mode Output Disable) to reserved. In Signal Tables chapter: – In Unused Signals table, corrected preferred and acceptable practices for RST pin. – Clarified GNDX pin description. In Electrical Characteristics chapter: – In Power-On and Brown-Out Levels table, corrected TVDDC_RISE parameter min and max values. – In PIOSC Clock Characteristics table, clarified FPIOSC parameter values by defining values for both factory calibration and recalibration. Also added PIOSC startup time parameter to table. – In Main Oscillator Specifications section, corrected minimum value for External load capacitance on OSC0, OSC1 pins. Also added two 25-MHz crystals to Crystal Parameters table. – Corrected figure "Master Mode SSI Timing for SPI Frame Format (FRF=00), with SPH=1". – In I2C Characteristics table, clarified TDH data hold time parameter values by defining values for both slave and master. In addition, added parameter I10 TDV data valid. – Modified figure "I2C Timing" to add new parameter I10. In Packaging Information appendix, added Packaging Materials figures. In the Electrical Characteristics chapter: – Added maximum junction temperature to Maximum Ratings table. Also moved Unpowered storage temperature range parameter to this table. – In SSI Characteristics table, corrected values for TRXDMS, TRXDMH, and TRXDSSU. Also clarified footnotes to table. June 12, 2014 33 Texas Instruments-Production Data Revision History Table 1. Revision History (continued) Date Revision Description – ■ July 2013 14995.2667 ■ ■ Corrected parameter numbers in figures "Master Mode SSI Timing for SPI Frame Format (FRF=00), with SPH=1" and "Slave Mode SSI Timing for SPI Frame Format (FRF=00), with SPH=1". Additional minor data sheet clarifications and corrections. In the System Control chapter, corrected resets for bits [7:4] in System Properties (SYSPROP) register. In the Hibernation Module chapter: – Corrected figures "Using a Crystal as the Hibernation Clock Source with a Single Battery Source" and "Using a Dedicated Oscillator as the Hibernation Clock Source with VDD3ON Mode". – Clarified when the Hibernation module can generate interrupts. ■ In the Internal Memory chapter, removed the INVPL bit from the EEPROM Done Status (EEDONE) register. ■ In the uDMA chapter, in the µDMA Channel Assignments table, corrected names of timers 6-11 to wide timers 0-5. ■ In the Timers chapter: – Clarified that the timer must be configured for one-shot or periodic time-out mode to produce an ADC trigger assertion and that the GPTM does not generate triggers for match, compare events or compare match events. – Added a step in the RTC Mode initialization and configuration: If the timer has been operating in a different mode prior to this, clear any residual set bits in the GPTM Timer n Mode (GPTMTnMR) register before reconfiguring. ■ In the Watchdog Timer chapter, added a note that locking the watchdog registers using the WDTLOCK register does not affect the WDTICR register and allows interrupts to always be serviced. ■ In the SSI chapter, clarified note in Bit Rate Generation section to indicate that the System Clock or the PIOSC can be used as the source for SSIClk. Also corrected to indicate maximum SSIClk limit in SSI slave mode as well as the fact that SYSCLK has to be at least 12 times that of SSICLk. ■ In the Electrical Characteristics chapter: – Moved Maximum Ratings and ESD Absolute Maximum Ratings to the front of the chapter. – Added VBATRMP parameter to Maximum Ratings and Hibernation Module Battery Characteristics tables. – Added ambient and junction temperatures to Temperature Characteristics table and clarified values in Thermal Characteristics table. – Added clarifying footnote to VVDD_POK parameter in Power-On and Brown-Out Levels table. – In the Flash Memory and EEPROM Characteristics tables, added a parameter for page/mass erase times for 10k cycles and corrected existing values for all page and mass erase parameters. – Corrected DNL max value in ADC Electrical Characteristics table. – In the SSI Characteristics table, changed parameter names for S7-S14, provided a max number instead of a min for S7, and corrected values for S9-S14. – Replaced figure "SSI Timing for SPI Frame Format (FRF=00), with SPH=1" with two figures, one for Master Mode and one for Slave Mode. – Updated and added values to the table Table 21-39 on page 1136. 34 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 1. Revision History (continued) Date Revision Description ■ In the Package Information appendix, moved orderable devices table from addendum to appendix, clarified part markings and moved packaging diagram from addendum to appendix. ■ Additional minor data sheet clarifications and corrections. June 12, 2014 35 Texas Instruments-Production Data About This Document About This Document This data sheet provides reference information for the TM4C1231H6PM microcontroller, describing the functional blocks of the system-on-chip (SoC) device designed around the ARM® Cortex™-M4F core. Audience This manual is intended for system software developers, hardware designers, and application developers. About This Manual This document is organized into sections that correspond to each major feature. Related Documents The following related documents are available on the Tiva™ C Series web site at http://www.ti.com/tiva-c: ■ Tiva™ C Series TM4C123x Silicon Errata (literature number SPMZ849) ■ TivaWare™ Boot Loader for C Series User's Guide (literature number SPMU301) ■ TivaWare™ Graphics Library for C Series User's Guide (literature number SPMU300) ■ TivaWare™ for C Series Release Notes (literature number SPMU299) ■ TivaWare™ Peripheral Driver Library for C Series User's Guide (literature number SPMU298) ■ TivaWare™ USB Library for C Series User's Guide (literature number SPMU297) ■ Tiva™ C Series TM4C123x ROM User’s Guide (literature number SPMU367) The following related documents may also be useful: ■ ARM® Cortex™-M4 Errata (literature number SPMZ637) ■ ARM® Cortex™-M4 Technical Reference Manual ■ ARM® Debug Interface V5 Architecture Specification ■ ARM® Embedded Trace Macrocell Architecture Specification ■ Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) ■ IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture This documentation list was current as of publication date. Please check the web site for additional documentation, including application notes and white papers. 36 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Documentation Conventions This document uses the conventions shown in Table 2 on page 37. Table 2. Documentation Conventions Notation Meaning General Register Notation REGISTER APB registers are indicated in uppercase bold. For example, PBORCTL is the Power-On and Brown-Out Reset Control register. If a register name contains a lowercase n, it represents more than one register. For example, SRCRn represents any (or all) of the three Software Reset Control registers: SRCR0, SRCR1 , and SRCR2. bit A single bit in a register. bit field Two or more consecutive and related bits. offset 0xnnn A hexadecimal increment to a register's address, relative to that module's base address as specified in Table 2-4 on page 82. Register N Registers are numbered consecutively throughout the document to aid in referencing them. The register number has no meaning to software. reserved Register bits marked reserved are reserved for future use. In most cases, reserved bits are set to 0; however, user software should not rely on the value of a reserved bit. To provide software compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. yy:xx The range of register bits inclusive from xx to yy. For example, 31:15 means bits 15 through 31 in that register. Register Bit/Field Types This value in the register bit diagram indicates whether software running on the controller can change the value of the bit field. RC Software can read this field. The bit or field is cleared by hardware after reading the bit/field. RO Software can read this field. Always write the chip reset value. RW Software can read or write this field. RWC Software can read or write this field. Writing to it with any value clears the register. RW1C Software can read or write this field. A write of a 0 to a W1C bit does not affect the bit value in the register. A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged. This register type is primarily used for clearing interrupt status bits where the read operation provides the interrupt status and the write of the read value clears only the interrupts being reported at the time the register was read. RW1S Software can read or write a 1 to this field. A write of a 0 to a RW1S bit does not affect the bit value in the register. W1C Software can write this field. A write of a 0 to a W1C bit does not affect the bit value in the register. A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged. A read of the register returns no meaningful data. This register is typically used to clear the corresponding bit in an interrupt register. WO Only a write by software is valid; a read of the register returns no meaningful data. Register Bit/Field Reset Value This value in the register bit diagram shows the bit/field value after any reset, unless noted. 0 Bit cleared to 0 on chip reset. 1 Bit set to 1 on chip reset. - Nondeterministic. Pin/Signal Notation [] Pin alternate function; a pin defaults to the signal without the brackets. pin Refers to the physical connection on the package. signal Refers to the electrical signal encoding of a pin. June 12, 2014 37 Texas Instruments-Production Data About This Document Table 2. Documentation Conventions (continued) Notation Meaning assert a signal Change the value of the signal from the logically False state to the logically True state. For active High signals, the asserted signal value is 1 (High); for active Low signals, the asserted signal value is 0 (Low). The active polarity (High or Low) is defined by the signal name (see SIGNAL and SIGNAL below). deassert a signal Change the value of the signal from the logically True state to the logically False state. SIGNAL Signal names are in uppercase and in the Courier font. An overbar on a signal name indicates that it is active Low. To assert SIGNAL is to drive it Low; to deassert SIGNAL is to drive it High. SIGNAL Signal names are in uppercase and in the Courier font. An active High signal has no overbar. To assert SIGNAL is to drive it High; to deassert SIGNAL is to drive it Low. Numbers X An uppercase X indicates any of several values is allowed, where X can be any legal pattern. For example, a binary value of 0X00 can be either 0100 or 0000, a hex value of 0xX is 0x0 or 0x1, and so on. 0x Hexadecimal numbers have a prefix of 0x. For example, 0x00FF is the hexadecimal number FF. All other numbers within register tables are assumed to be binary. Within conceptual information, binary numbers are indicated with a b suffix, for example, 1011b, and decimal numbers are written without a prefix or suffix. 38 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 1 Architectural Overview ® Texas Instrument's Tiva™ C Series microcontrollers provide designers a high-performance ARM Cortex™-M-based architecture with a broad set of integration capabilities and a strong ecosystem of software and development tools. Targeting performance and flexibility, the Tiva™ C Series architecture offers a 80 MHz Cortex-M with FPU, a variety of integrated memories and multiple programmable GPIO. Tiva™ C Series devices offer consumers compelling cost-effective solutions by integrating application-specific peripherals and providing a comprehensive library of software tools which minimize board costs and design-cycle time. Offering quicker time-to-market and cost savings, the Tiva™ C Series microcontrollers are the leading choice in high-performance 32-bit applications. This chapter contains an overview of the Tiva™ C Series microcontrollers as well as details on the TM4C1231H6PM microcontroller: ■ ■ ■ ■ ■ ■ 1.1 “Tiva™ C Series Overview” on page 39 “TM4C1231H6PM Microcontroller Overview” on page 40 “TM4C1231H6PM Microcontroller Features” on page 42 “TM4C1231H6PM Microcontroller Hardware Details” on page 58 “Kits” on page 58 “Support Information” on page 58 Tiva™ C Series Overview The Tiva™ C Series ARM Cortex-M4 microcontrollers provide top performance and advanced integration. The product family is positioned for cost-conscious applications requiring significant control processing and connectivity capabilities such as: ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Low power, hand-held smart devices Gaming equipment Home and commercial site monitoring and control Motion control Medical instrumentation Test and measurement equipment Factory automation Fire and security Smart Energy/Smart Grid solutions Intelligent lighting control Transportation For applications requiring extreme conservation of power, the TM4C1231H6PM microcontroller features a battery-backed Hibernation module to efficiently power down the TM4C1231H6PM to a low-power state during extended periods of inactivity. With a power-up/power-down sequencer, a real-time counter (RTC), multiple wake-from-hibernate options, and dedicated battery-backed memory, the Hibernation module positions the TM4C1231H6PM microcontroller perfectly for battery applications. In addition, the TM4C1231H6PM microcontroller offers the advantages of ARM's widely available development tools, System-on-Chip (SoC) infrastructure IP applications, and a large user community. Additionally, the microcontroller uses ARM's Thumb®-compatible Thumb-2 instruction set to reduce memory requirements and, thereby, cost. Finally, much of the TM4C1231H6PM microcontroller code is compatible to the Tiva™ C Series product line, providing flexibility across designs. June 12, 2014 39 Texas Instruments-Production Data Architectural Overview Texas Instruments offers a complete solution to get to market quickly, with evaluation and development boards, white papers and application notes, an easy-to-use peripheral driver library, and a strong support, sales, and distributor network. 1.2 TM4C1231H6PM Microcontroller Overview The TM4C1231H6PM microcontroller combines complex integration and high performance with the features shown in Table 1-1. Table 1-1. TM4C1231H6PM Microcontroller Features Feature Description Performance Core ARM Cortex-M4F processor core Performance 80-MHz operation; 100 DMIPS performance Flash 256 KB single-cycle Flash memory System SRAM 32 KB single-cycle SRAM EEPROM 2KB of EEPROM Internal ROM Internal ROM loaded with TivaWare™ for C Series software Security Communication Interfaces Universal Asynchronous Receivers/Transmitter (UART) Eight UARTs Synchronous Serial Interface (SSI) Four SSI modules Inter-Integrated Circuit (I2C) Four I2C modules with four transmission speeds including high-speed mode Controller Area Network (CAN) CAN 2.0 A/B controllers System Integration Micro Direct Memory Access (µDMA) ARM® PrimeCell® 32-channel configurable μDMA controller General-Purpose Timer (GPTM) Six 16/32-bit GPTM blocks and six 32/64-bit Wide GPTM blocks Watchdog Timer (WDT) Two watchdog timers Hibernation Module (HIB) Low-power battery-backed Hibernation module General-Purpose Input/Output (GPIO) Six physical GPIO blocks Analog Support Analog-to-Digital Converter (ADC) Two 12-bit ADC modules, each with a maximum sample rate of one million samples/second Analog Comparator Controller Two independent integrated analog comparators Digital Comparator 16 digital comparators JTAG and Serial Wire Debug (SWD) One JTAG module with integrated ARM SWD Package Information Package 64-pin LQFP Operating Range (Ambient) Industrial (-40°C to 85°C) temperature range Figure 1-1 on page 41 shows the features on the TM4C1231H6PM microcontroller. Note that there are two on-chip buses that connect the core to the peripherals. The Advanced Peripheral Bus (APB) bus is the legacy bus. The Advanced High-Performance Bus (AHB) bus provides better back-to-back access performance than the APB bus. 40 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 1-1. Tiva™ TM4C1231H6PM Microcontroller High-Level Block Diagram JTAG/SWD ARM® Cortex™-M4F ROM (80MHz) System Control and Clocks (w/ Precis. Osc.) ETM FPU NVIC MPU Boot Loader DriverLib AES & CRC Flash (256KB) DCode bus ICode bus System Bus TM4C1231H6PM Bus Matrix SRAM (32KB) SYSTEM PERIPHERALS EEPROM (2K) Hibernation Module GPIOs (43) I2C (4) CAN Controller (1) Advanced Peripheral Bus (APB) Watchdog Timer (2) Advanced High-Performance Bus (AHB) DMA GeneralPurpose Timer (12) SERIAL PERIPHERALS UART (8) SSI (4) ANALOG PERIPHERALS Analog Comparator (2) 12- Bit ADC Channels (12) June 12, 2014 41 Texas Instruments-Production Data Architectural Overview 1.3 TM4C1231H6PM Microcontroller Features The TM4C1231H6PM microcontroller component features and general function are discussed in more detail in the following section. 1.3.1 ARM Cortex-M4F Processor Core All members of the Tiva™ C Series, including the TM4C1231H6PM microcontroller, are designed around an ARM Cortex-M processor core. The ARM Cortex-M processor provides the core for a high-performance, low-cost platform that meets the needs of minimal memory implementation, reduced pin count, and low power consumption, while delivering outstanding computational performance and exceptional system response to interrupts. 1.3.1.1 Processor Core (see page 59) ■ 32-bit ARM Cortex-M4F architecture optimized for small-footprint embedded applications ■ 80-MHz operation; 100 DMIPS performance ■ Outstanding processing performance combined with fast interrupt handling ■ Thumb-2 mixed 16-/32-bit instruction set delivers the high performance expected of a 32-bit ARM core in a compact memory size usually associated with 8- and 16-bit devices, typically in the range of a few kilobytes of memory for microcontroller-class applications – Single-cycle multiply instruction and hardware divide – Atomic bit manipulation (bit-banding), delivering maximum memory utilization and streamlined peripheral control – Unaligned data access, enabling data to be efficiently packed into memory ■ IEEE754-compliant single-precision Floating-Point Unit (FPU) ■ 16-bit SIMD vector processing unit ■ Fast code execution permits slower processor clock or increases sleep mode time ■ Harvard architecture characterized by separate buses for instruction and data ■ Efficient processor core, system and memories ■ Hardware division and fast digital-signal-processing orientated multiply accumulate ■ Saturating arithmetic for signal processing ■ Deterministic, high-performance interrupt handling for time-critical applications ■ Memory protection unit (MPU) to provide a privileged mode for protected operating system functionality ■ Enhanced system debug with extensive breakpoint and trace capabilities ■ Serial Wire Debug and Serial Wire Trace reduce the number of pins required for debugging and tracing 42 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller ■ Migration from the ARM7™ processor family for better performance and power efficiency ■ Optimized for single-cycle Flash memory usage up to specific frequencies; see “Internal Memory” on page 489 for more information. ■ Ultra-low power consumption with integrated sleep modes 1.3.1.2 System Timer (SysTick) (see page 113) ARM Cortex-M4F includes an integrated system timer, SysTick. SysTick provides a simple, 24-bit, clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter can be used in several different ways, for example: ■ An RTOS tick timer that fires at a programmable rate (for example, 100 Hz) and invokes a SysTick routine ■ A high-speed alarm timer using the system clock ■ A variable rate alarm or signal timer—the duration is range-dependent on the reference clock used and the dynamic range of the counter ■ A simple counter used to measure time to completion and time used ■ An internal clock-source control based on missing/meeting durations 1.3.1.3 Nested Vectored Interrupt Controller (NVIC) (see page 114) The TM4C1231H6PM controller includes the ARM Nested Vectored Interrupt Controller (NVIC). The NVIC and Cortex-M4F prioritize and handle all exceptions in Handler Mode. The processor state is automatically stored to the stack on an exception and automatically restored from the stack at the end of the Interrupt Service Routine (ISR). The interrupt vector is fetched in parallel to the state saving, enabling efficient interrupt entry. The processor supports tail-chaining, meaning that back-to-back interrupts can be performed without the overhead of state saving and restoration. Software can set eight priority levels on 7 exceptions (system handlers) and 64 interrupts. ■ Deterministic, fast interrupt processing: always 12 cycles, or just 6 cycles with tail-chaining (these values reflect no FPU stacking) ■ External non-maskable interrupt signal (NMI) available for immediate execution of NMI handler for safety critical applications ■ Dynamically reprioritizable interrupts ■ Exceptional interrupt handling via hardware implementation of required register manipulations 1.3.1.4 System Control Block (SCB) (see page 115) The SCB provides system implementation information and system control, including configuration, control, and reporting of system exceptions. 1.3.1.5 Memory Protection Unit (MPU) (see page 115) The MPU supports the standard ARM7 Protected Memory System Architecture (PMSA) model. The MPU provides full support for protection regions, overlapping protection regions, access permissions, and exporting memory attributes to the system. June 12, 2014 43 Texas Instruments-Production Data Architectural Overview 1.3.1.6 Floating-Point Unit (FPU) (see page 120) The FPU fully supports single-precision add, subtract, multiply, divide, multiply and accumulate, and square root operations. It also provides conversions between fixed-point and floating-point data formats, and floating-point constant instructions. ■ 32-bit instructions for single-precision (C float) data-processing operations ■ Combined multiply and accumulate instructions for increased precision (Fused MAC) ■ Hardware support for conversion, addition, subtraction, multiplication with optional accumulate, division, and square-root ■ Hardware support for denormals and all IEEE rounding modes ■ 32 dedicated 32-bit single-precision registers, also addressable as 16 double-word registers ■ Decoupled three stage pipeline 1.3.2 On-Chip Memory The TM4C1231H6PM microcontroller is integrated with the following set of on-chip memory and features: ■ 32 KB single-cycle SRAM ■ 256 KB Flash memory ■ 2KB EEPROM ■ Internal ROM loaded with TivaWare™ for C Series software: – TivaWare™ Peripheral Driver Library – TivaWare Boot Loader – Advanced Encryption Standard (AES) cryptography tables – Cyclic Redundancy Check (CRC) error detection functionality 1.3.2.1 SRAM (see page 490) The TM4C1231H6PM microcontroller provides 32 KB of single-cycle on-chip SRAM. The internal SRAM of the device is located at offset 0x2000.0000 of the device memory map. Because read-modify-write (RMW) operations are very time consuming, ARM has introduced bit-banding technology in the Cortex-M4F processor. With a bit-band-enabled processor, certain regions in the memory map (SRAM and peripheral space) can use address aliases to access individual bits in a single, atomic operation. Data can be transferred to and from SRAM by the following masters: ■ µDMA 1.3.2.2 Flash Memory (see page 493) The TM4C1231H6PM microcontroller provides 256 KB of single-cycle on-chip Flash memory. The Flash memory is organized as a set of 1-KB blocks that can be individually erased. Erasing a block causes the entire contents of the block to be reset to all 1s. These blocks are paired into a set of 2-KB blocks that can be individually protected. The blocks can be marked as read-only or execute-only, providing different levels of code protection. Read-only blocks cannot be erased or 44 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller programmed, protecting the contents of those blocks from being modified. Execute-only blocks cannot be erased or programmed, and can only be read by the controller instruction fetch mechanism, protecting the contents of those blocks from being read by either the controller or by a debugger. 1.3.2.3 ROM (see page 491) The TM4C1231H6PM ROM is preprogrammed with the following software and programs: ■ TivaWare Peripheral Driver Library ■ TivaWare Boot Loader ■ Advanced Encryption Standard (AES) cryptography tables ■ Cyclic Redundancy Check (CRC) error-detection functionality The TivaWare Peripheral Driver Library is a royalty-free software library for controlling on-chip peripherals with a boot-loader capability. The library performs both peripheral initialization and control functions, with a choice of polled or interrupt-driven peripheral support. In addition, the library is designed to take full advantage of the stellar interrupt performance of the ARM Cortex-M4F core. No special pragmas or custom assembly code prologue/epilogue functions are required. For applications that require in-field programmability, the royalty-free TivaWare Boot Loader can act as an application loader and support in-field firmware updates. The Advanced Encryption Standard (AES) is a publicly defined encryption standard used by the U.S. Government. AES is a strong encryption method with reasonable performance and size. In addition, it is fast in both hardware and software, is fairly easy to implement, and requires little memory. The Texas Instruments encryption package is available with full source code, and is based on Lesser General Public License (LGPL) source. An LGPL means that the code can be used within an application without any copyleft implications for the application (the code does not automatically become open source). Modifications to the package source, however, must be open source. CRC (Cyclic Redundancy Check) is a technique to validate a span of data has the same contents as when previously checked. This technique can be used to validate correct receipt of messages (nothing lost or modified in transit), to validate data after decompression, to validate that Flash memory contents have not been changed, and for other cases where the data needs to be validated. A CRC is preferred over a simple checksum (for example, XOR all bits) because it catches changes more readily. 1.3.2.4 EEPROM (see page 499) The TM4C1231H6PM microcontroller includes an EEPROM with the following features: ■ 2Kbytes of memory accessible as 512 32-bit words ■ 32 blocks of 16 words (64 bytes) each ■ Built-in wear leveling ■ Access protection per block ■ Lock protection option for the whole peripheral as well as per block using 32-bit to 96-bit unlock codes (application selectable) ■ Interrupt support for write completion to avoid polling June 12, 2014 45 Texas Instruments-Production Data Architectural Overview ■ Endurance of 500K writes (when writing at fixed offset in every alternate page in circular fashion) to 15M operations (when cycling through two pages ) per each 2-page block. 1.3.3 Serial Communications Peripherals The TM4C1231H6PM controller supports both asynchronous and synchronous serial communications with: ■ CAN 2.0 A/B controller ■ Eight UARTs with IrDA, 9-bit and ISO 7816 support. ■ Four I2C modules with four transmission speeds including high-speed mode ■ Four Synchronous Serial Interface modules (SSI) The following sections provide more detail on each of these communications functions. 1.3.3.1 Controller Area Network (CAN) (see page 1010) Controller Area Network (CAN) is a multicast shared serial-bus standard for connecting electronic control units (ECUs). CAN was specifically designed to be robust in electromagnetically noisy environments and can utilize a differential balanced line like RS-485 or twisted-pair wire. Originally created for automotive purposes, it is now used in many embedded control applications (for example, industrial or medical). Bit rates up to 1 Mbps are possible at network lengths below 40 meters. Decreased bit rates allow longer network distances (for example, 125 Kbps at 500m). A transmitter sends a message to all CAN nodes (broadcasting). Each node decides on the basis of the identifier received whether it should process the message. The identifier also determines the priority that the message enjoys in competition for bus access. Each CAN message can transmit from 0 to 8 bytes of user information. The TM4C1231H6PM microcontroller includes one CAN unit with the following features: ■ CAN protocol version 2.0 part A/B ■ Bit rates up to 1 Mbps ■ 32 message objects with individual identifier masks ■ Maskable interrupt ■ Disable Automatic Retransmission mode for Time-Triggered CAN (TTCAN) applications ■ Programmable loopback mode for self-test operation ■ Programmable FIFO mode enables storage of multiple message objects ■ Gluelessly attaches to an external CAN transceiver through the CANnTX and CANnRX signals 1.3.3.2 UART (see page 855) A Universal Asynchronous Receiver/Transmitter (UART) is an integrated circuit used for RS-232C serial communications, containing a transmitter (parallel-to-serial converter) and a receiver (serial-to-parallel converter), each clocked separately. The TM4C1231H6PM microcontroller includes eight fully programmable 16C550-type UARTs. Although the functionality is similar to a 16C550 UART, this UART design is not register compatible. 46 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller The UART can generate individually masked interrupts from the Rx, Tx, modem flow control, and error conditions. The module generates a single combined interrupt when any of the interrupts are asserted and are unmasked. The eight UARTs have the following features: ■ Programmable baud-rate generator allowing speeds up to 5 Mbps for regular speed (divide by 16) and 10 Mbps for high speed (divide by 8) ■ Separate 16x8 transmit (TX) and receive (RX) FIFOs to reduce CPU interrupt service loading ■ Programmable FIFO length, including 1-byte deep operation providing conventional double-buffered interface ■ FIFO trigger levels of 1/8, 1/4, 1/2, 3/4, and 7/8 ■ Standard asynchronous communication bits for start, stop, and parity ■ Line-break generation and detection ■ Fully programmable serial interface characteristics – 5, 6, 7, or 8 data bits – Even, odd, stick, or no-parity bit generation/detection – 1 or 2 stop bit generation ■ IrDA serial-IR (SIR) encoder/decoder providing – Programmable use of IrDA Serial Infrared (SIR) or UART input/output – Support of IrDA SIR encoder/decoder functions for data rates up to 115.2 Kbps half-duplex – Support of normal 3/16 and low-power (1.41-2.23 μs) bit durations – Programmable internal clock generator enabling division of reference clock by 1 to 256 for low-power mode bit duration ■ Support for communication with ISO 7816 smart cards ■ Modem flow control (on UART1) ■ EIA-485 9-bit support ■ Standard FIFO-level and End-of-Transmission interrupts ■ Efficient transfers using Micro Direct Memory Access Controller (µDMA) – Separate channels for transmit and receive – Receive single request asserted when data is in the FIFO; burst request asserted at programmed FIFO level – Transmit single request asserted when there is space in the FIFO; burst request asserted at programmed FIFO level June 12, 2014 47 Texas Instruments-Production Data Architectural Overview 1.3.3.3 I2C (see page 959) The Inter-Integrated Circuit (I2C) bus provides bi-directional data transfer through a two-wire design (a serial data line SDA and a serial clock line SCL). The I2C bus interfaces to external I2C devices such as serial memory (RAMs and ROMs), networking devices, LCDs, tone generators, and so on. The I2C bus may also be used for system testing and diagnostic purposes in product development and manufacture. Each device on the I2C bus can be designated as either a master or a slave. I2C module supports both sending and receiving data as either a master or a slave and can operate simultaneously as both a master and a slave. Both the I2C master and slave can generate interrupts. The TM4C1231H6PM microcontroller includes four I2C modules with the following features: ■ Devices on the I2C bus can be designated as either a master or a slave – Supports both transmitting and receiving data as either a master or a slave – Supports simultaneous master and slave operation ■ Four I2C modes – Master transmit – Master receive – Slave transmit – Slave receive ■ Four transmission speeds: – Standard (100 Kbps) – Fast-mode (400 Kbps) – Fast-mode plus (1 Mbps) – High-speed mode (3.33 Mbps) ■ Clock low timeout interrupt ■ Dual slave address capability ■ Glitch suppression ■ Master and slave interrupt generation – Master generates interrupts when a transmit or receive operation completes (or aborts due to an error) – Slave generates interrupts when data has been transferred or requested by a master or when a START or STOP condition is detected ■ Master with arbitration and clock synchronization, multimaster support, and 7-bit addressing mode 48 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 1.3.3.4 SSI (see page 914) Synchronous Serial Interface (SSI) is a four-wire bi-directional communications interface that converts data between parallel and serial. The SSI module performs serial-to-parallel conversion on data received from a peripheral device, and parallel-to-serial conversion on data transmitted to a peripheral device. The SSI module can be configured as either a master or slave device. As a slave device, the SSI module can also be configured to disable its output, which allows a master device to be coupled with multiple slave devices. The TX and RX paths are buffered with separate internal FIFOs. The SSI module also includes a programmable bit rate clock divider and prescaler to generate the output serial clock derived from the SSI module's input clock. Bit rates are generated based on the input clock and the maximum bit rate is determined by the connected peripheral. The TM4C1231H6PM microcontroller includes four SSI modules with the following features: ■ Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces ■ Master or slave operation ■ Programmable clock bit rate and prescaler ■ Separate transmit and receive FIFOs, each 16 bits wide and 8 locations deep ■ Programmable data frame size from 4 to 16 bits ■ Internal loopback test mode for diagnostic/debug testing ■ Standard FIFO-based interrupts and End-of-Transmission interrupt ■ Efficient transfers using Micro Direct Memory Access Controller (µDMA) – Separate channels for transmit and receive – Receive single request asserted when data is in the FIFO; burst request asserted when FIFO contains 4 entries – Transmit single request asserted when there is space in the FIFO; burst request asserted when four or more entries are available to be written in the FIFO 1.3.4 System Integration The TM4C1231H6PM microcontroller provides a variety of standard system functions integrated into the device, including: ■ Direct Memory Access Controller (DMA) ■ System control and clocks including on-chip precision 16-MHz oscillator ■ Six 32-bit timers (up to twelve 16-bit) ■ Six wide 64-bit timers (up to twelve 32-bit) ■ Twelve 32/64-bit Capture Compare PWM (CCP) pins ■ Lower-power battery-backed Hibernation module June 12, 2014 49 Texas Instruments-Production Data Architectural Overview ■ Real-Time Clock in Hibernation module ■ Two Watchdog Timers – One timer runs off the main oscillator – One timer runs off the precision internal oscillator ■ Up to 43 GPIOs, depending on configuration – Highly flexible pin muxing allows use as GPIO or one of several peripheral functions – Independently configurable to 2-, 4- or 8-mA drive capability – Up to 4 GPIOs can have 18-mA drive capability The following sections provide more detail on each of these functions. 1.3.4.1 Direct Memory Access (see page 550) The TM4C1231H6PM microcontroller includes a Direct Memory Access (DMA) controller, known as micro-DMA (μDMA). The μDMA controller provides a way to offload data transfer tasks from the Cortex-M4F processor, allowing for more efficient use of the processor and the available bus bandwidth. The μDMA controller can perform transfers between memory and peripherals. It has dedicated channels for each supported on-chip module and can be programmed to automatically perform transfers between peripherals and memory as the peripheral is ready to transfer more data. The μDMA controller provides the following features: ® ■ ARM PrimeCell 32-channel configurable µDMA controller ■ Support for memory-to-memory, memory-to-peripheral, and peripheral-to-memory in multiple transfer modes – Basic for simple transfer scenarios – Ping-pong for continuous data flow – Scatter-gather for a programmable list of up to 256 arbitrary transfers initiated from a single request ■ Highly flexible and configurable channel operation – Independently configured and operated channels – Dedicated channels for supported on-chip modules – Flexible channel assignments – One channel each for receive and transmit path for bidirectional modules – Dedicated channel for software-initiated transfers – Per-channel configurable priority scheme – Optional software-initiated requests for any channel ■ Two levels of priority ■ Design optimizations for improved bus access performance between µDMA controller and the processor core 50 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller – µDMA controller access is subordinate to core access – RAM striping – Peripheral bus segmentation ■ Data sizes of 8, 16, and 32 bits ■ Transfer size is programmable in binary steps from 1 to 1024 ■ Source and destination address increment size of byte, half-word, word, or no increment ■ Maskable peripheral requests ■ Interrupt on transfer completion, with a separate interrupt per channel 1.3.4.2 System Control and Clocks (see page 202) System control determines the overall operation of the device. It provides information about the device, controls power-saving features, controls the clocking of the device and individual peripherals, and handles reset detection and reporting. ■ Device identification information: version, part number, SRAM size, Flash memory size, and so on ■ Power control – On-chip fixed Low Drop-Out (LDO) voltage regulator – Hibernation module handles the power-up/down 3.3 V sequencing and control for the core digital logic and analog circuits – Low-power options for microcontroller: Sleep and Deep-Sleep modes with clock gating – Low-power options for on-chip modules: software controls shutdown of individual peripherals and memory – 3.3-V supply brown-out detection and reporting via interrupt or reset ■ Multiple clock sources for microcontroller system clock. The following clock sources are provided to the TM4C1231H6PM microcontroller: – Precision Internal Oscillator (PIOSC) providing a 16-MHz frequency • 16 MHz ±3% across temperature and voltage • Can be recalibrated with 7-bit trim resolution to achieve better accuracy (16 MHz ±1%) • Software power down control for low power modes – Main Oscillator (MOSC): A frequency-accurate clock source by one of two means: an external single-ended clock source is connected to the OSC0 input pin, or an external crystal is connected across the OSC0 input and OSC1 output pins. – Low Frequency Internal Oscillator (LFIOSC): On-chip resource used during power-saving modes June 12, 2014 51 Texas Instruments-Production Data Architectural Overview – Hibernate RTC oscillator (RTCOSC) clock that can be configured to be the 32.768-kHz external oscillator source from the Hibernation (HIB) module or the HIB Low Frequency clock source (HIB LFIOSC), which is located within the Hibernation Module. ■ Flexible reset sources – Power-on reset (POR) – Reset pin assertion – Brown-out reset (BOR) detector alerts to system power drops – Software reset – Watchdog timer reset – MOSC failure 1.3.4.3 Programmable Timers (see page 669) Programmable timers can be used to count or time external events that drive the Timer input pins. Each 16/32-bit GPTM block provides two 16-bit timers/counters that can be configured to operate independently as timers or event counters, or configured to operate as one 32-bit timer or one 32-bit Real-Time Clock (RTC). Each 32/64-bit Wide GPTM block provides two 32-bit timers/counters that can be configured to operate independently as timersor event counters, or configured to operate as one 64-bit timer or one 64-bit Real-Time Clock (RTC). Timers can also be used to trigger analog-to-digital (ADC) conversions and DMA transfers. The General-Purpose Timer Module (GPTM) contains six 16/32-bit GPTM blocks and six 32/64-bit Wide GPTM blocks with the following functional options: ■ 16/32-bit operating modes: – 16- or 32-bit programmable one-shot timer – 16- or 32-bit programmable periodic timer – 16-bit general-purpose timer with an 8-bit prescaler – 32-bit Real-Time Clock (RTC) when using an external 32.768-KHz clock as the input – 16-bit input-edge count- or time-capture modes with an 8-bit prescaler – 16-bit PWM mode with an 8-bit prescaler and software-programmable output inversion of the PWM signal ■ 32/64-bit operating modes: – 32- or 64-bit programmable one-shot timer – 32- or 64-bit programmable periodic timer – 32-bit general-purpose timer with a 16-bit prescaler – 64-bit Real-Time Clock (RTC) when using an external 32.768-KHz clock as the input – 32-bit input-edge count- or time-capture modes with a16-bit prescaler 52 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller – 32-bit PWM mode with a 16-bit prescaler and software-programmable output inversion of the PWM signal ■ Count up or down ■ Twelve 16/32-bit Capture Compare PWM pins (CCP) ■ Twelve 32/64-bit Capture Compare PWM pins (CCP) ■ Daisy chaining of timer modules to allow a single timer to initiate multiple timing events ■ Timer synchronization allows selected timers to start counting on the same clock cycle ■ ADC event trigger ■ User-enabled stalling when the microcontroller asserts CPU Halt flag during debug (excluding RTC mode) ■ Ability to determine the elapsed time between the assertion of the timer interrupt and entry into the interrupt service routine ■ Efficient transfers using Micro Direct Memory Access Controller (µDMA) – Dedicated channel for each timer – Burst request generated on timer interrupt 1.3.4.4 CCP Pins (see page 677) Capture Compare PWM pins (CCP) can be used by the General-Purpose Timer Module to time/count external events using the CCP pin as an input. Alternatively, the GPTM can generate a simple PWM output on the CCP pin. The TM4C1231H6PM microcontroller includes twelve 16/32-bit CCP pins that can be programmed to operate in the following modes: ■ Capture: The GP Timer is incremented/decremented by programmed events on the CCP input. The GP Timer captures and stores the current timer value when a programmed event occurs. ■ Compare: The GP Timer is incremented/decremented by programmed events on the CCP input. The GP Timer compares the current value with a stored value and generates an interrupt when a match occurs. ■ PWM: The GP Timer is incremented/decremented by the system clock. A PWM signal is generated based on a match between the counter value and a value stored in a match register and is output on the CCP pin. 1.3.4.5 Hibernation Module (HIB) (see page 458) The Hibernation module provides logic to switch power off to the main processor and peripherals and to wake on external or time-based events. The Hibernation module includes power-sequencing logic and has the following features: ■ 32-bit real-time seconds counter (RTC) with 1/32,768 second resolution and a 15-bit sub-seconds counter June 12, 2014 53 Texas Instruments-Production Data Architectural Overview – 32-bit RTC seconds match register and a 15-bit sub seconds match for timed wake-up and interrupt generation with 1/32,768 second resolution – RTC predivider trim for making fine adjustments to the clock rate ■ Two mechanisms for power control – System power control using discrete external regulator – On-chip power control using internal switches under register control ■ Dedicated pin for waking using an external signal ■ RTC operational and hibernation memory valid as long as VDD or VBAT is valid ■ Low-battery detection, signaling, and interrupt generation, with optional wake on low battery ■ GPIO pin state can be retained during hibernation ■ Clock source from a 32.768-kHz external crystal or oscillator ■ Sixteen 32-bit words of battery-backed memory to save state during hibernation ■ Programmable interrupts for: – RTC match – External wake – Low battery 1.3.4.6 Watchdog Timers (see page 739) A watchdog timer is used to regain control when a system has failed due to a software error or to the failure of an external device to respond in the expected way. The TM4C1231H6PM Watchdog Timer can generate an interrupt, a non-maskable interrupt, or a reset when a time-out value is reached. In addition, the Watchdog Timer is ARM FiRM-compliant and can be configured to generate an interrupt to the microcontroller on its first time-out, and to generate a reset signal on its second timeout. Once the Watchdog Timer has been configured, the lock register can be written to prevent the timer configuration from being inadvertently altered. The TM4C1231H6PM microcontroller has two Watchdog Timer modules: Watchdog Timer 0 uses the system clock for its timer clock; Watchdog Timer 1 uses the PIOSC as its timer clock. The Watchdog Timer module has the following features: ■ 32-bit down counter with a programmable load register ■ Separate watchdog clock with an enable ■ Programmable interrupt generation logic with interrupt masking and optional NMI function ■ Lock register protection from runaway software ■ Reset generation logic with an enable/disable ■ User-enabled stalling when the microcontroller asserts the CPU Halt flag during debug 54 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 1.3.4.7 Programmable GPIOs (see page 614) General-purpose input/output (GPIO) pins offer flexibility for a variety of connections. The TM4C1231H6PM GPIO module is comprised of six physical GPIO blocks, each corresponding to an individual GPIO port. The GPIO module is FiRM-compliant (compliant to the ARM Foundation IP for Real-Time Microcontrollers specification) and supports 0-43 programmable input/output pins. The number of GPIOs available depends on the peripherals being used (see “Signal Tables” on page 1076 for the signals available to each GPIO pin). ■ Up to 43 GPIOs, depending on configuration ■ Highly flexible pin muxing allows use as GPIO or one of several peripheral functions ■ 5-V-tolerant in input configuration ■ Ports A-G accessed through the Advanced Peripheral Bus (APB) ■ Fast toggle capable of a change every clock cycle for ports on AHB, every two clock cycles for ports on APB ■ Programmable control for GPIO interrupts – Interrupt generation masking – Edge-triggered on rising, falling, or both – Level-sensitive on High or Low values ■ Bit masking in both read and write operations through address lines ■ Can be used to initiate an ADC sample sequence or a μDMA transfer ■ Pin state can be retained during Hibernation mode ■ Pins configured as digital inputs are Schmitt-triggered ■ Programmable control for GPIO pad configuration – Weak pull-up or pull-down resistors – 2-mA, 4-mA, and 8-mA pad drive for digital communication; up to four pads can sink 18-mA for high-current applications – Slew rate control for 8-mA pad drive – Open drain enables – Digital input enables 1.3.5 Analog The TM4C1231H6PM microcontroller provides analog functions integrated into the device, including: ■ Two 12-bit Analog-to-Digital Converters (ADC), with a total of 12 analog input channels and each with a sample rate of one million samples/second ■ Two analog comparators June 12, 2014 55 Texas Instruments-Production Data Architectural Overview ■ On-chip voltage regulator The following provides more detail on these analog functions. 1.3.5.1 ADC (see page 764) An analog-to-digital converter (ADC) is a peripheral that converts a continuous analog voltage to a discrete digital number. The TM4C1231H6PM ADC module features 12-bit conversion resolution and supports 12 input channels plus an internal temperature sensor. Four buffered sample sequencers allow rapid sampling of up to 12 analog input sources without controller intervention. Each sample sequencer provides flexible programming with fully configurable input source, trigger events, interrupt generation, and sequencer priority. Each ADC module has a digital comparator function that allows the conversion value to be diverted to a comparison unit that provides eight digital comparators. The TM4C1231H6PM microcontroller provides two ADC modules, each with the following features: ■ 12 shared analog input channels ■ 12-bit precision ADC ■ Single-ended and differential-input configurations ■ On-chip internal temperature sensor ■ Maximum sample rate of one million samples/second ■ Optional phase shift in sample time programmable from 22.5º to 337.5º ■ Four programmable sample conversion sequencers from one to eight entries long, with corresponding conversion result FIFOs ■ Flexible trigger control – Controller (software) – Timers – Analog Comparators – GPIO ■ Hardware averaging of up to 64 samples ■ Eight digital comparators ■ Power and ground for the analog circuitry is separate from the digital power and ground ■ Efficient transfers using Micro Direct Memory Access Controller (µDMA) – Dedicated channel for each sample sequencer – ADC module uses burst requests for DMA 56 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 1.3.5.2 Analog Comparators (see page 1060) An analog comparator is a peripheral that compares two analog voltages and provides a logical output that signals the comparison result. The TM4C1231H6PM microcontroller provides two independent integrated analog comparators that can be configured to drive an output or generate an interrupt or ADC event. The comparator can provide its output to a device pin, acting as a replacement for an analog comparator on the board, or it can be used to signal the application via interrupts or triggers to the ADC to cause it to start capturing a sample sequence. The interrupt generation and ADC triggering logic is separate. This means, for example, that an interrupt can be generated on a rising edge and the ADC triggered on a falling edge. The TM4C1231H6PM microcontroller provides two independent integrated analog comparators with the following functions: ■ Compare external pin input to external pin input or to internal programmable voltage reference ■ Compare a test voltage against any one of the following voltages: – An individual external reference voltage – A shared single external reference voltage – A shared internal reference voltage 1.3.6 JTAG and ARM Serial Wire Debug (see page 190) The Joint Test Action Group (JTAG) port is an IEEE standard that defines a Test Access Port and Boundary Scan Architecture for digital integrated circuits and provides a standardized serial interface for controlling the associated test logic. The TAP, Instruction Register (IR), and Data Registers (DR) can be used to test the interconnections of assembled printed circuit boards and obtain manufacturing information on the components. The JTAG Port also provides a means of accessing and controlling design-for-test features such as I/O pin observation and control, scan testing, and debugging. Texas Instruments replaces the ARM SW-DP and JTAG-DP with the ARM Serial Wire JTAG Debug Port (SWJ-DP) interface. The SWJ-DP interface combines the SWD and JTAG debug ports into one module providing all the normal JTAG debug and test functionality plus real-time access to system memory without halting the core or requiring any target resident code. The SWJ-DP interface has the following features: ■ IEEE 1149.1-1990 compatible Test Access Port (TAP) controller ■ Four-bit Instruction Register (IR) chain for storing JTAG instructions ■ IEEE standard instructions: BYPASS, IDCODE, SAMPLE/PRELOAD, and EXTEST ■ ARM additional instructions: APACC, DPACC and ABORT ■ Integrated ARM Serial Wire Debug (SWD) – Serial Wire JTAG Debug Port (SWJ-DP) – Flash Patch and Breakpoint (FPB) unit for implementing breakpoints – Data Watchpoint and Trace (DWT) unit for implementing watchpoints, trigger resources, and system profiling June 12, 2014 57 Texas Instruments-Production Data Architectural Overview – Instrumentation Trace Macrocell (ITM) for support of printf style debugging – Embedded Trace Macrocell (ETM) for instruction trace capture – Trace Port Interface Unit (TPIU) for bridging to a Trace Port Analyzer 1.3.7 Packaging and Temperature ■ 64-pin RoHS-compliant LQFP package ■ Industrial (-40°C to 85°C) ambient temperature range 1.4 TM4C1231H6PM Microcontroller Hardware Details Details on the pins and package can be found in the following sections: ■ “Pin Diagram” on page 1075 ■ “Signal Tables” on page 1076 ■ “Electrical Characteristics” on page 1096 ■ “Package Information” on page 1139 1.5 Kits The Tiva™ C Series provides the hardware and software tools that engineers need to begin development quickly. ■ Reference Design Kits accelerate product development by providing ready-to-run hardware and comprehensive documentation including hardware design files ■ Evaluation Kits provide a low-cost and effective means of evaluating TM4C1231H6PM microcontrollers before purchase ■ Development Kits provide you with all the tools you need to develop and prototype embedded applications right out of the box See the Tiva series website at http://www.ti.com/tiva-c for the latest tools available, or ask your distributor. 1.6 Support Information For support on Tiva™ C Series products, contact the TI Worldwide Product Information Center nearest you. 58 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 2 The Cortex-M4F Processor The ARM® Cortex™-M4F processor provides a high-performance, low-cost platform that meets the system requirements of minimal memory implementation, reduced pin count, and low power consumption, while delivering outstanding computational performance and exceptional system response to interrupts. Features include: ® ■ 32-bit ARM Cortex™-M4F architecture optimized for small-footprint embedded applications ■ 80-MHz operation; 100 DMIPS performance ■ Outstanding processing performance combined with fast interrupt handling ■ Thumb-2 mixed 16-/32-bit instruction set delivers the high performance expected of a 32-bit ARM core in a compact memory size usually associated with 8- and 16-bit devices, typically in the range of a few kilobytes of memory for microcontroller-class applications – Single-cycle multiply instruction and hardware divide – Atomic bit manipulation (bit-banding), delivering maximum memory utilization and streamlined peripheral control – Unaligned data access, enabling data to be efficiently packed into memory ■ IEEE754-compliant single-precision Floating-Point Unit (FPU) ■ 16-bit SIMD vector processing unit ■ Fast code execution permits slower processor clock or increases sleep mode time ■ Harvard architecture characterized by separate buses for instruction and data ■ Efficient processor core, system and memories ■ Hardware division and fast digital-signal-processing orientated multiply accumulate ■ Saturating arithmetic for signal processing ■ Deterministic, high-performance interrupt handling for time-critical applications ■ Memory protection unit (MPU) to provide a privileged mode for protected operating system functionality ■ Enhanced system debug with extensive breakpoint and trace capabilities ■ Serial Wire Debug and Serial Wire Trace reduce the number of pins required for debugging and tracing ■ Migration from the ARM7™ processor family for better performance and power efficiency ■ Optimized for single-cycle Flash memory usage up to specific frequencies; see “Internal Memory” on page 489 for more information. ■ Ultra-low power consumption with integrated sleep modes June 12, 2014 59 Texas Instruments-Production Data The Cortex-M4F Processor The Tiva™ C Series microcontrollers builds on this core to bring high-performance 32-bit computing to This chapter provides information on the Tiva™ C Series implementation of the Cortex-M4F processor, including the programming model, the memory model, the exception model, fault handling, and power management. For technical details on the instruction set, see the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A). 2.1 Block Diagram The Cortex-M4F processor is built on a high-performance processor core, with a 3-stage pipeline Harvard architecture, making it ideal for demanding embedded applications. The processor delivers exceptional power efficiency through an efficient instruction set and extensively optimized design, providing high-end processing hardware including IEEE754-compliant single-precision floating-point computation, a range of single-cycle and SIMD multiplication and multiply-with-accumulate capabilities, saturating arithmetic and dedicated hardware division. To facilitate the design of cost-sensitive devices, the Cortex-M4F processor implements tightly coupled system components that reduce processor area while significantly improving interrupt handling and system debug capabilities. The Cortex-M4F processor implements a version of the Thumb® instruction set based on Thumb-2 technology, ensuring high code density and reduced program memory requirements. The Cortex-M4F instruction set provides the exceptional performance expected of a modern 32-bit architecture, with the high code density of 8-bit and 16-bit microcontrollers. The Cortex-M4F processor closely integrates a nested interrupt controller (NVIC), to deliver industry-leading interrupt performance. The TM4C1231H6PM NVIC includes a non-maskable interrupt (NMI) and provides eight interrupt priority levels. The tight integration of the processor core and NVIC provides fast execution of interrupt service routines (ISRs), dramatically reducing interrupt latency. The hardware stacking of registers and the ability to suspend load-multiple and store-multiple operations further reduce interrupt latency. Interrupt handlers do not require any assembler stubs which removes code overhead from the ISRs. Tail-chaining optimization also significantly reduces the overhead when switching from one ISR to another. To optimize low-power designs, the NVIC integrates with the sleep modes, including Deep-sleep mode, which enables the entire device to be rapidly powered down. 60 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 2-1. CPU Block Diagram Nested Vectored Interrupt Controller FPU Interrupts Sleep ARM Cortex-M4F CM4 Core Debug Instructions Data Embedded Trace Macrocell Memory Protection Unit Flash Patch and Breakpoint Instrumentation Data Watchpoint Trace Macrocell and Trace ROM Table Private Peripheral Bus (internal) Adv. Peripheral Bus Bus Matrix Serial Wire JTAG Debug Port Debug Access Port 2.2 Overview 2.2.1 System-Level Interface Trace Port Interface Unit Serial Wire Output Trace Port (SWO) I-code bus D-code bus System bus The Cortex-M4F processor provides multiple interfaces using AMBA® technology to provide high-speed, low-latency memory accesses. The core supports unaligned data accesses and implements atomic bit manipulation that enables faster peripheral controls, system spinlocks, and thread-safe Boolean data handling. The Cortex-M4F processor has a memory protection unit (MPU) that provides fine-grain memory control, enabling applications to implement security privilege levels and separate code, data and stack on a task-by-task basis. 2.2.2 Integrated Configurable Debug The Cortex-M4F processor implements a complete hardware debug solution, providing high system visibility of the processor and memory through either a traditional JTAG port or a 2-pin Serial Wire Debug (SWD) port that is ideal for microcontrollers and other small package devices. The Tiva™ C Series implementation replaces the ARM SW-DP and JTAG-DP with the ARM CoreSight™-compliant Serial Wire JTAG Debug Port (SWJ-DP) interface. The SWJ-DP interface combines the SWD and JTAG debug ports into one module. See the ARM® Debug Interface V5 Architecture Specification for details on SWJ-DP. For system trace, the processor integrates an Instrumentation Trace Macrocell (ITM) alongside data watchpoints and a profiling unit. To enable simple and cost-effective profiling of the system trace events, a Serial Wire Viewer (SWV) can export a stream of software-generated messages, data trace, and profiling information through a single pin. June 12, 2014 61 Texas Instruments-Production Data The Cortex-M4F Processor The Embedded Trace Macrocell (ETM) delivers unrivaled instruction trace capture in an area smaller than traditional trace units, enabling full instruction trace. For more details on the ARM ETM, see the ARM® Embedded Trace Macrocell Architecture Specification. The Flash Patch and Breakpoint Unit (FPB) provides up to eight hardware breakpoint comparators that debuggers can use. The comparators in the FPB also provide remap functions for up to eight words of program code in the code memory region. This FPB enables applications stored in a read-only area of Flash memory to be patched in another area of on-chip SRAM or Flash memory. If a patch is required, the application programs the FPB to remap a number of addresses. When those addresses are accessed, the accesses are redirected to a remap table specified in the FPB configuration. For more information on the Cortex-M4F debug capabilities, see theARM® Debug Interface V5 Architecture Specification. 2.2.3 Trace Port Interface Unit (TPIU) The TPIU acts as a bridge between the Cortex-M4F trace data from the ITM, and an off-chip Trace Port Analyzer, as shown in Figure 2-2 on page 62. Figure 2-2. TPIU Block Diagram 2.2.4 Debug ATB Slave Port ARM® Trace Bus (ATB) Interface APB Slave Port Advance Peripheral Bus (APB) Interface Asynchronous FIFO Trace Out (serializer) Serial Wire Trace Port (SWO) Cortex-M4F System Component Details The Cortex-M4F includes the following system components: ■ SysTick A 24-bit count-down timer that can be used as a Real-Time Operating System (RTOS) tick timer or as a simple counter (see “System Timer (SysTick)” on page 113). ■ Nested Vectored Interrupt Controller (NVIC) 62 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller An embedded interrupt controller that supports low latency interrupt processing (see “Nested Vectored Interrupt Controller (NVIC)” on page 114). ■ System Control Block (SCB) The programming model interface to the processor. The SCB provides system implementation information and system control, including configuration, control, and reporting of system exceptions (see “System Control Block (SCB)” on page 115). ■ Memory Protection Unit (MPU) Improves system reliability by defining the memory attributes for different memory regions. The MPU provides up to eight different regions and an optional predefined background region (see “Memory Protection Unit (MPU)” on page 115). ■ Floating-Point Unit (FPU) Fully supports single-precision add, subtract, multiply, divide, multiply and accumulate, and square-root operations. It also provides conversions between fixed-point and floating-point data formats, and floating-point constant instructions (see “Floating-Point Unit (FPU)” on page 120). 2.3 Programming Model This section describes the Cortex-M4F programming model. In addition to the individual core register descriptions, information about the processor modes and privilege levels for software execution and stacks is included. 2.3.1 Processor Mode and Privilege Levels for Software Execution The Cortex-M4F has two modes of operation: ■ Thread mode Used to execute application software. The processor enters Thread mode when it comes out of reset. ■ Handler mode Used to handle exceptions. When the processor has finished exception processing, it returns to Thread mode. In addition, the Cortex-M4F has two privilege levels: ■ Unprivileged In this mode, software has the following restrictions: – Limited access to the MSR and MRS instructions and no use of the CPS instruction – No access to the system timer, NVIC, or system control block – Possibly restricted access to memory or peripherals ■ Privileged In this mode, software can use all the instructions and has access to all resources. In Thread mode, the CONTROL register (see page 78) controls whether software execution is privileged or unprivileged. In Handler mode, software execution is always privileged. June 12, 2014 63 Texas Instruments-Production Data The Cortex-M4F Processor Only privileged software can write to the CONTROL register to change the privilege level for software execution in Thread mode. Unprivileged software can use the SVC instruction to make a supervisor call to transfer control to privileged software. 2.3.2 Stacks The processor uses a full descending stack, meaning that the stack pointer indicates the last stacked item on the memory. When the processor pushes a new item onto the stack, it decrements the stack pointer and then writes the item to the new memory location. The processor implements two stacks: the main stack and the process stack, with a pointer for each held in independent registers (see the SP register on page 68). In Thread mode, the CONTROL register (see page 78) controls whether the processor uses the main stack or the process stack. In Handler mode, the processor always uses the main stack. The options for processor operations are shown in Table 2-1 on page 64. Table 2-1. Summary of Processor Mode, Privilege Level, and Stack Use Processor Mode Use Privilege Level Thread Applications Privileged or unprivileged Handler Exception handlers Always privileged Stack Used a Main stack or process stack a Main stack a. See CONTROL (page 78). 2.3.3 Register Map Figure 2-3 on page 65 shows the Cortex-M4F register set. Table 2-2 on page 65 lists the Core registers. The core registers are not memory mapped and are accessed by register name, so the base address is n/a (not applicable) and there is no offset. 64 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 2-3. Cortex-M4F Register Set R0 R1 R2 R3 Low registers R4 R5 General-purpose registers R6 R7 R8 R9 High registers R10 R11 R12 Stack Pointer SP (R13) Link Register LR (R14) Program Counter PC (R15) PSP‡ PSR MSP‡ ‡ Banked version of SP Program status register PRIMASK FAULTMASK Exception mask registers Special registers BASEPRI CONTROL CONTROL register Table 2-2. Processor Register Map Offset Name Type Reset Description See page - R0 RW - Cortex General-Purpose Register 0 67 - R1 RW - Cortex General-Purpose Register 1 67 - R2 RW - Cortex General-Purpose Register 2 67 - R3 RW - Cortex General-Purpose Register 3 67 - R4 RW - Cortex General-Purpose Register 4 67 - R5 RW - Cortex General-Purpose Register 5 67 - R6 RW - Cortex General-Purpose Register 6 67 - R7 RW - Cortex General-Purpose Register 7 67 - R8 RW - Cortex General-Purpose Register 8 67 - R9 RW - Cortex General-Purpose Register 9 67 - R10 RW - Cortex General-Purpose Register 10 67 - R11 RW - Cortex General-Purpose Register 11 67 June 12, 2014 65 Texas Instruments-Production Data The Cortex-M4F Processor Table 2-2. Processor Register Map (continued) Offset Name Type Reset Description See page - R12 RW - Cortex General-Purpose Register 12 67 - SP RW - Stack Pointer 68 - LR RW 0xFFFF.FFFF Link Register 69 - PC RW - Program Counter 70 - PSR RW 0x0100.0000 Program Status Register 71 - PRIMASK RW 0x0000.0000 Priority Mask Register 75 - FAULTMASK RW 0x0000.0000 Fault Mask Register 76 - BASEPRI RW 0x0000.0000 Base Priority Mask Register 77 - CONTROL RW 0x0000.0000 Control Register 78 - FPSC RW - Floating-Point Status Control 80 2.3.4 Register Descriptions This section lists and describes the Cortex-M4F registers, in the order shown in Figure 2-3 on page 65. The core registers are not memory mapped and are accessed by register name rather than offset. Note: The register type shown in the register descriptions refers to type during program execution in Thread mode and Handler mode. Debug access can differ. 66 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 1: Cortex General-Purpose Register 0 (R0) Register 2: Cortex General-Purpose Register 1 (R1) Register 3: Cortex General-Purpose Register 2 (R2) Register 4: Cortex General-Purpose Register 3 (R3) Register 5: Cortex General-Purpose Register 4 (R4) Register 6: Cortex General-Purpose Register 5 (R5) Register 7: Cortex General-Purpose Register 6 (R6) Register 8: Cortex General-Purpose Register 7 (R7) Register 9: Cortex General-Purpose Register 8 (R8) Register 10: Cortex General-Purpose Register 9 (R9) Register 11: Cortex General-Purpose Register 10 (R10) Register 12: Cortex General-Purpose Register 11 (R11) Register 13: Cortex General-Purpose Register 12 (R12) The Rn registers are 32-bit general-purpose registers for data operations and can be accessed from either privileged or unprivileged mode. Cortex General-Purpose Register 0 (R0) Type RW, reset 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - DATA Type Reset DATA Type Reset Bit/Field Name Type Reset 31:0 DATA RW - Description Register data. June 12, 2014 67 Texas Instruments-Production Data The Cortex-M4F Processor Register 14: Stack Pointer (SP) The Stack Pointer (SP) is register R13. In Thread mode, the function of this register changes depending on the ASP bit in the Control Register (CONTROL) register. When the ASP bit is clear, this register is the Main Stack Pointer (MSP). When the ASP bit is set, this register is the Process Stack Pointer (PSP). On reset, the ASP bit is clear, and the processor loads the MSP with the value from address 0x0000.0000. The MSP can only be accessed in privileged mode; the PSP can be accessed in either privileged or unprivileged mode. Stack Pointer (SP) Type RW, reset 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - SP Type Reset SP Type Reset Bit/Field Name Type Reset 31:0 SP RW - Description This field is the address of the stack pointer. 68 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 15: Link Register (LR) The Link Register (LR) is register R14, and it stores the return information for subroutines, function calls, and exceptions. The Link Register can be accessed from either privileged or unprivileged mode. EXC_RETURN is loaded into the LR on exception entry. See Table 2-10 on page 101 for the values and description. Link Register (LR) Type RW, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 7 6 5 4 3 2 1 0 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 LINK Type Reset RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 15 14 13 12 11 10 9 8 LINK Type Reset RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 Bit/Field Name Type 31:0 LINK RW RW 1 Reset RW 1 Description 0xFFFF.FFFF This field is the return address. June 12, 2014 69 Texas Instruments-Production Data The Cortex-M4F Processor Register 16: Program Counter (PC) The Program Counter (PC) is register R15, and it contains the current program address. On reset, the processor loads the PC with the value of the reset vector, which is at address 0x0000.0004. Bit 0 of the reset vector is loaded into the THUMB bit of the EPSR at reset and must be 1. The PC register can be accessed in either privileged or unprivileged mode. Program Counter (PC) Type RW, reset 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - RW - PC Type Reset PC Type Reset Bit/Field Name Type Reset 31:0 PC RW - Description This field is the current program address. 70 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 17: Program Status Register (PSR) Note: This register is also referred to as xPSR. The Program Status Register (PSR) has three functions, and the register bits are assigned to the different functions: ■ Application Program Status Register (APSR), bits 31:27, bits 19:16 ■ Execution Program Status Register (EPSR), bits 26:24, 15:10 ■ Interrupt Program Status Register (IPSR), bits 7:0 The PSR, IPSR, and EPSR registers can only be accessed in privileged mode; the APSR register can be accessed in either privileged or unprivileged mode. APSR contains the current state of the condition flags from previous instruction executions. EPSR contains the Thumb state bit and the execution state bits for the If-Then (IT) instruction or the Interruptible-Continuable Instruction (ICI) field for an interrupted load multiple or store multiple instruction. Attempts to read the EPSR directly through application software using the MSR instruction always return zero. Attempts to write the EPSR using the MSR instruction in application software are always ignored. Fault handlers can examine the EPSR value in the stacked PSR to determine the operation that faulted (see “Exception Entry and Return” on page 98). IPSR contains the exception type number of the current Interrupt Service Routine (ISR). These registers can be accessed individually or as a combination of any two or all three registers, using the register name as an argument to the MSR or MRS instructions. For example, all of the registers can be read using PSR with the MRS instruction, or APSR only can be written to using APSR with the MSR instruction. page 71 shows the possible register combinations for the PSR. See the MRS and MSR instruction descriptions in the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) for more information about how to access the program status registers. Table 2-3. PSR Register Combinations Register Type PSR RW Combination APSR, EPSR, and IPSR IEPSR RO EPSR and IPSR a, b a APSR and IPSR b APSR and EPSR IAPSR RW EAPSR RW a. The processor ignores writes to the IPSR bits. b. Reads of the EPSR bits return zero, and the processor ignores writes to these bits. Program Status Register (PSR) Type RW, reset 0x0100.0000 Type Reset 31 30 29 28 27 N Z C V Q 26 RW 0 RW 0 RW 0 RW 0 RW 0 RO 0 RO 0 RO 1 RO 0 RO 0 RO 0 RO 0 RW 0 15 14 13 12 11 10 9 8 7 6 5 4 ICI / IT Type Reset RO 0 RO 0 RO 0 25 ICI / IT 24 23 22 THUMB 21 RO 0 RO 0 RO 0 RO 0 19 18 17 16 RW 0 RW 0 RW 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 GE reserved RO 0 20 reserved ISRNUM RO 0 RO 0 June 12, 2014 RO 0 RO 0 71 Texas Instruments-Production Data The Cortex-M4F Processor Bit/Field Name Type Reset 31 N RW 0 Description APSR Negative or Less Flag Value Description 1 The previous operation result was negative or less than. 0 The previous operation result was positive, zero, greater than, or equal. The value of this bit is only meaningful when accessing PSR or APSR. 30 Z RW 0 APSR Zero Flag Value Description 1 The previous operation result was zero. 0 The previous operation result was non-zero. The value of this bit is only meaningful when accessing PSR or APSR. 29 C RW 0 APSR Carry or Borrow Flag Value Description 1 The previous add operation resulted in a carry bit or the previous subtract operation did not result in a borrow bit. 0 The previous add operation did not result in a carry bit or the previous subtract operation resulted in a borrow bit. The value of this bit is only meaningful when accessing PSR or APSR. 28 V RW 0 APSR Overflow Flag Value Description 1 The previous operation resulted in an overflow. 0 The previous operation did not result in an overflow. The value of this bit is only meaningful when accessing PSR or APSR. 27 Q RW 0 APSR DSP Overflow and Saturation Flag Value Description 1 DSP Overflow or saturation has occurred when using a SIMD instruction. 0 DSP overflow or saturation has not occurred since reset or since the bit was last cleared. The value of this bit is only meaningful when accessing PSR or APSR. This bit is cleared by software using an MRS instruction. 72 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 26:25 ICI / IT RO 0x0 Description EPSR ICI / IT status These bits, along with bits 15:10, contain the Interruptible-Continuable Instruction (ICI) field for an interrupted load multiple or store multiple instruction or the execution state bits of the IT instruction. When EPSR holds the ICI execution state, bits 26:25 are zero. The If-Then block contains up to four instructions following an IT instruction. Each instruction in the block is conditional. The conditions for the instructions are either all the same, or some can be the inverse of others. See the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) for more information. The value of this field is only meaningful when accessing PSR or EPSR. Note that these EPSR bits cannot be accessed using MRS and MSR instructions but the definitions are provided to allow the stacked (E)PSR value to be decoded within an exception handler. 24 THUMB RO 1 EPSR Thumb State This bit indicates the Thumb state and should always be set. The following can clear the THUMB bit: ■ The BLX, BX and POP{PC} instructions ■ Restoration from the stacked xPSR value on an exception return ■ Bit 0 of the vector value on an exception entry or reset Attempting to execute instructions when this bit is clear results in a fault or lockup. See “Lockup” on page 103 for more information. The value of this bit is only meaningful when accessing PSR or EPSR. 23:20 reserved RO 0x00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 19:16 GE RW 0x0 Greater Than or Equal Flags See the description of the SEL instruction in the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) for more information. The value of this field is only meaningful when accessing PSR or APSR. June 12, 2014 73 Texas Instruments-Production Data The Cortex-M4F Processor Bit/Field Name Type Reset 15:10 ICI / IT RO 0x0 Description EPSR ICI / IT status These bits, along with bits 26:25, contain the Interruptible-Continuable Instruction (ICI) field for an interrupted load multiple or store multiple instruction or the execution state bits of the IT instruction. When an interrupt occurs during the execution of an LDM, STM, PUSH POP, VLDM, VSTM, VPUSH, or VPOP instruction, the processor stops the load multiple or store multiple instruction operation temporarily and stores the next register operand in the multiple operation to bits 15:12. After servicing the interrupt, the processor returns to the register pointed to by bits 15:12 and resumes execution of the multiple load or store instruction. When EPSR holds the ICI execution state, bits 11:10 are zero. The If-Then block contains up to four instructions following a 16-bit IT instruction. Each instruction in the block is conditional. The conditions for the instructions are either all the same, or some can be the inverse of others. See the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) for more information. The value of this field is only meaningful when accessing PSR or EPSR. 9:8 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 ISRNUM RO 0x00 IPSR ISR Number This field contains the exception type number of the current Interrupt Service Routine (ISR). Value Description 0x00 Thread mode 0x01 Reserved 0x02 NMI 0x03 Hard fault 0x04 Memory management fault 0x05 Bus fault 0x06 Usage fault 0x07-0x0A Reserved 0x0B SVCall 0x0C Reserved for Debug 0x0D Reserved 0x0E PendSV 0x0F SysTick 0x10 Interrupt Vector 0 0x11 Interrupt Vector 1 ... ... 0x9A Interrupt Vector 138 See “Exception Types” on page 92 for more information. The value of this field is only meaningful when accessing PSR or IPSR. 74 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 18: Priority Mask Register (PRIMASK) The PRIMASK register prevents activation of all exceptions with programmable priority. Reset, non-maskable interrupt (NMI), and hard fault are the only exceptions with fixed priority. Exceptions should be disabled when they might impact the timing of critical tasks. This register is only accessible in privileged mode. The MSR and MRS instructions are used to access the PRIMASK register, and the CPS instruction may be used to change the value of the PRIMASK register. See the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) for more information on these instructions. For more information on exception priority levels, see “Exception Types” on page 92. Priority Mask Register (PRIMASK) Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:1 reserved RO 0x0000.000 0 PRIMASK RW 0 RO 0 PRIMASK RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Priority Mask Value Description 1 Prevents the activation of all exceptions with configurable priority. 0 No effect. June 12, 2014 75 Texas Instruments-Production Data The Cortex-M4F Processor Register 19: Fault Mask Register (FAULTMASK) The FAULTMASK register prevents activation of all exceptions except for the Non-Maskable Interrupt (NMI). Exceptions should be disabled when they might impact the timing of critical tasks. This register is only accessible in privileged mode. The MSR and MRS instructions are used to access the FAULTMASK register, and the CPS instruction may be used to change the value of the FAULTMASK register. See the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) for more information on these instructions. For more information on exception priority levels, see “Exception Types” on page 92. Fault Mask Register (FAULTMASK) Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:1 reserved RO 0x0000.000 0 FAULTMASK RW 0 RO 0 FAULTMASK RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Fault Mask Value Description 1 Prevents the activation of all exceptions except for NMI. 0 No effect. The processor clears the FAULTMASK bit on exit from any exception handler except the NMI handler. 76 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 20: Base Priority Mask Register (BASEPRI) The BASEPRI register defines the minimum priority for exception processing. When BASEPRI is set to a nonzero value, it prevents the activation of all exceptions with the same or lower priority level as the BASEPRI value. Exceptions should be disabled when they might impact the timing of critical tasks. This register is only accessible in privileged mode. For more information on exception priority levels, see “Exception Types” on page 92. Base Priority Mask Register (BASEPRI) Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RW 0 RW 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset BASEPRI RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:5 BASEPRI RW 0x0 RW 0 reserved RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Base Priority Any exception that has a programmable priority level with the same or lower priority as the value of this field is masked. The PRIMASK register can be used to mask all exceptions with programmable priority levels. Higher priority exceptions have lower priority levels. Value Description 4:0 reserved RO 0x0 0x0 All exceptions are unmasked. 0x1 All exceptions with priority level 1-7 are masked. 0x2 All exceptions with priority level 2-7 are masked. 0x3 All exceptions with priority level 3-7 are masked. 0x4 All exceptions with priority level 4-7 are masked. 0x5 All exceptions with priority level 5-7 are masked. 0x6 All exceptions with priority level 6-7 are masked. 0x7 All exceptions with priority level 7 are masked. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 12, 2014 77 Texas Instruments-Production Data The Cortex-M4F Processor Register 21: Control Register (CONTROL) The CONTROL register controls the stack used and the privilege level for software execution when the processor is in Thread mode, and indicates whether the FPU state is active. This register is only accessible in privileged mode. Handler mode always uses the MSP, so the processor ignores explicit writes to the ASP bit of the CONTROL register when in Handler mode. The exception entry and return mechanisms automatically update the CONTROL register based on the EXC_RETURN value (see Table 2-10 on page 101). In an OS environment, threads running in Thread mode should use the process stack and the kernel and exception handlers should use the main stack. By default, Thread mode uses the MSP. To switch the stack pointer used in Thread mode to the PSP, either use the MSR instruction to set the ASP bit, as detailed in the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A), or perform an exception return to Thread mode with the appropriate EXC_RETURN value, as shown in Table 2-10 on page 101. Note: When changing the stack pointer, software must use an ISB instruction immediately after the MSR instruction, ensuring that instructions after the ISB execute use the new stack pointer. See the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A). Control Register (CONTROL) Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 FPCA ASP TMPL RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset 31:3 reserved RO 0x0000.000 2 FPCA RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Floating-Point Context Active Value Description 1 Floating-point context active 0 No floating-point context active The Cortex-M4F uses this bit to determine whether to preserve floating-point state when processing an exception. Important: Two bits control when FPCA can be enabled: the ASPEN bit in the Floating-Point Context Control (FPCC) register and the DISFPCA bit in the Auxiliary Control (ACTLR) register. 78 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 1 ASP RW 0 Description Active Stack Pointer Value Description 1 The PSP is the current stack pointer. 0 The MSP is the current stack pointer In Handler mode, this bit reads as zero and ignores writes. The Cortex-M4F updates this bit automatically on exception return. 0 TMPL RW 0 Thread Mode Privilege Level Value Description 1 Unprivileged software can be executed in Thread mode. 0 Only privileged software can be executed in Thread mode. June 12, 2014 79 Texas Instruments-Production Data The Cortex-M4F Processor Register 22: Floating-Point Status Control (FPSC) The FPSC register provides all necessary user-level control of the floating-point system. Floating-Point Status Control (FPSC) Type RW, reset 31 Type Reset 30 29 28 27 26 25 24 22 21 20 19 RMODE 18 17 16 N Z C V reserved AHP DN FZ RW - RW - RW - RW - RO 0 RW - RW - RW - RW - RW - RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 IXC UFC OFC DZC IOC RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW - RW - RW - RW - RW - reserved Type Reset 23 IDC RO 0 Bit/Field Name Type Reset 31 N RW - RW - reserved reserved RO 0 RO 0 Description Negative Condition Code Flag Floating-point comparison operations update this condition code flag. 30 Z RW - Zero Condition Code Flag Floating-point comparison operations update this condition code flag. 29 C RW - Carry Condition Code Flag Floating-point comparison operations update this condition code flag. 28 V RW - Overflow Condition Code Flag Floating-point comparison operations update this condition code flag. 27 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 26 AHP RW - Alternative Half-Precision When set, alternative half-precision format is selected. When clear, IEEE half-precision format is selected. The AHP bit in the FPDSC register holds the default value for this bit. 25 DN RW - Default NaN Mode When set, any operation involving one or more NaNs returns the Default NaN. When clear, NaN operands propagate through to the output of a floating-point operation. The DN bit in the FPDSC register holds the default value for this bit. 24 FZ RW - Flush-to-Zero Mode When set, Flush-to-Zero mode is enabled. When clear, Flush-to-Zero mode is disabled and the behavior of the floating-point system is fully compliant with the IEEE 754 standard. The FZ bit in the FPDSC register holds the default value for this bit. 80 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 23:22 RMODE RW - Description Rounding Mode The specified rounding mode is used by almost all floating-point instructions. The RMODE bit in the FPDSC register holds the default value for this bit. Value Description 21:8 reserved RO 0x0 7 IDC RW - 0x0 Round to Nearest (RN) mode 0x1 Round towards Plus Infinity (RP) mode 0x2 Round towards Minus Infinity (RM) mode 0x3 Round towards Zero (RZ) mode Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Input Denormal Cumulative Exception When set, indicates this exception has occurred since 0 was last written to this bit. 6:5 reserved RO 0x0 4 IXC RW - Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Inexact Cumulative Exception When set, indicates this exception has occurred since 0 was last written to this bit. 3 UFC RW - Underflow Cumulative Exception When set, indicates this exception has occurred since 0 was last written to this bit. 2 OFC RW - Overflow Cumulative Exception When set, indicates this exception has occurred since 0 was last written to this bit. 1 DZC RW - Division by Zero Cumulative Exception When set, indicates this exception has occurred since 0 was last written to this bit. 0 IOC RW - Invalid Operation Cumulative Exception When set, indicates this exception has occurred since 0 was last written to this bit. June 12, 2014 81 Texas Instruments-Production Data The Cortex-M4F Processor 2.3.5 Exceptions and Interrupts The Cortex-M4F processor supports interrupts and system exceptions. The processor and the Nested Vectored Interrupt Controller (NVIC) prioritize and handle all exceptions. An exception changes the normal flow of software control. The processor uses Handler mode to handle all exceptions except for reset. See “Exception Entry and Return” on page 98 for more information. The NVIC registers control interrupt handling. See “Nested Vectored Interrupt Controller (NVIC)” on page 114 for more information. 2.3.6 Data Types The Cortex-M4F supports 32-bit words, 16-bit halfwords, and 8-bit bytes. The processor also supports 64-bit data transfer instructions. All instruction and data memory accesses are little endian. See “Memory Regions, Types and Attributes” on page 84 for more information. 2.4 Memory Model This section describes the processor memory map, the behavior of memory accesses, and the bit-banding features. The processor has a fixed memory map that provides up to 4 GB of addressable memory. The memory map for the TM4C1231H6PM controller is provided in Table 2-4 on page 82. In this manual, register addresses are given as a hexadecimal increment, relative to the module's base address as shown in the memory map. The regions for SRAM and peripherals include bit-band regions. Bit-banding provides atomic operations to bit data (see “Bit-Banding” on page 87). The processor reserves regions of the Private peripheral bus (PPB) address range for core peripheral registers (see “Cortex-M4 Peripherals” on page 112). Note: Within the memory map, attempts to read or write addresses in reserved spaces result in a bus fault. In addition, attempts to write addresses in the flash range also result in a bus fault. Table 2-4. Memory Map Start End Description For details, see page ... 0x0000.0000 0x0003.FFFF On-chip Flash 505 0x0004.0000 0x1FFF.FFFF Reserved - 0x2000.0000 0x2000.7FFF Bit-banded on-chip SRAM 490 0x2000.8000 0x21FF.FFFF Reserved - 0x2200.0000 0x220F.FFFF Bit-band alias of bit-banded on-chip SRAM starting at 0x2000.0000 490 0x2210.0000 0x3FFF.FFFF Reserved - 0x4000.0000 0x4000.0FFF Watchdog timer 0 741 0x4000.1000 0x4000.1FFF Watchdog timer 1 741 0x4000.2000 0x4000.3FFF Reserved - 0x4000.4000 0x4000.4FFF GPIO Port A 623 0x4000.5000 0x4000.5FFF GPIO Port B 623 Memory Peripherals 82 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 2-4. Memory Map (continued) Start End Description For details, see page ... 0x4000.6000 0x4000.6FFF GPIO Port C 623 0x4000.7000 0x4000.7FFF GPIO Port D 623 0x4000.8000 0x4000.8FFF SSI0 929 0x4000.9000 0x4000.9FFF SSI1 929 0x4000.A000 0x4000.AFFF SSI2 929 0x4000.B000 0x4000.BFFF SSI3 929 0x4000.C000 0x4000.CFFF UART0 865 0x4000.D000 0x4000.DFFF UART1 865 0x4000.E000 0x4000.EFFF UART2 865 0x4000.F000 0x4000.FFFF UART3 865 0x4001.0000 0x4001.0FFF UART4 865 0x4001.1000 0x4001.1FFF UART5 865 0x4001.2000 0x4001.2FFF UART6 865 0x4001.3000 0x4001.3FFF UART7 865 0x4001.4000 0x4001.FFFF Reserved - 0x4002.0FFF I2C 0 979 0x4002.1FFF I2C 1 979 0x4002.2000 0x4002.2FFF I2C 2 979 0x4002.3000 0x4002.3FFF I2C 3 979 0x4002.4000 0x4002.4FFF GPIO Port E 623 0x4002.5000 0x4002.5FFF GPIO Port F 623 0x4002.6000 0x4002.FFFF Reserved - 0x4003.0000 0x4003.0FFF 16/32-bit Timer 0 690 0x4003.1000 0x4003.1FFF 16/32-bit Timer 1 690 0x4003.2000 0x4003.2FFF 16/32-bit Timer 2 690 0x4003.3000 0x4003.3FFF 16/32-bit Timer 3 690 0x4003.4000 0x4003.4FFF 16/32-bit Timer 4 690 0x4003.5000 0x4003.5FFF 16/32-bit Timer 5 690 0x4003.6000 0x4003.6FFF 32/64-bit Timer 0 690 0x4003.7000 0x4003.7FFF 32/64-bit Timer 1 690 0x4003.8000 0x4003.8FFF ADC0 783 0x4003.9000 0x4003.9FFF ADC1 783 0x4003.A000 0x4003.BFFF Reserved - 0x4003.C000 0x4003.CFFF Analog Comparators 1065 0x4003.D000 0x4003.FFFF Reserved - 0x4004.0000 0x4004.0FFF CAN0 Controller 1029 0x4004.1000 0x4004.BFFF Reserved - 0x4004.C000 0x4004.CFFF 32/64-bit Timer 2 690 0x4004.D000 0x4004.DFFF 32/64-bit Timer 3 690 0x4004.E000 0x4004.EFFF 32/64-bit Timer 4 690 Peripherals 0x4002.0000 0x4002.1000 June 12, 2014 83 Texas Instruments-Production Data The Cortex-M4F Processor Table 2-4. Memory Map (continued) Start End Description For details, see page ... 0x4004.F000 0x4004.FFFF 32/64-bit Timer 5 690 0x4005.0000 0x4005.7FFF Reserved - 0x4005.8000 0x4005.8FFF GPIO Port A (AHB aperture) 623 0x4005.9000 0x4005.9FFF GPIO Port B (AHB aperture) 623 0x4005.A000 0x4005.AFFF GPIO Port C (AHB aperture) 623 0x4005.B000 0x4005.BFFF GPIO Port D (AHB aperture) 623 0x4005.C000 0x4005.CFFF GPIO Port E (AHB aperture) 623 0x4005.D000 0x4005.DFFF GPIO Port F (AHB aperture) 623 0x4005.E000 0x400A.EFFF Reserved - 0x400A.F000 0x400A.FFFF EEPROM and Key Locker 505 0x400B.0000 0x400F.8FFF Reserved - 0x400F.9000 0x400F.9FFF System Exception Module 450 0x400F.A000 0x400F.BFFF Reserved - 0x400F.C000 0x400F.CFFF Hibernation Module 470 0x400F.D000 0x400F.DFFF Flash memory control 505 0x400F.E000 0x400F.EFFF System control 220 0x400F.F000 0x400F.FFFF µDMA 571 0x4010.0000 0x41FF.FFFF Reserved - 0x4200.0000 0x43FF.FFFF Bit-banded alias of 0x4000.0000 through 0x400F.FFFF - 0x4400.0000 0xDFFF.FFFF Reserved - 0xE000.0000 0xE000.0FFF Instrumentation Trace Macrocell (ITM) 61 0xE000.1000 0xE000.1FFF Data Watchpoint and Trace (DWT) 61 0xE000.2000 0xE000.2FFF Flash Patch and Breakpoint (FPB) 61 0xE000.3000 0xE000.DFFF Reserved - 0xE000.E000 0xE000.EFFF Cortex-M4F Peripherals (SysTick, NVIC, MPU, FPU and SCB) 124 0xE000.F000 0xE003.FFFF Reserved - 0xE004.0000 0xE004.0FFF Trace Port Interface Unit (TPIU) 62 0xE004.1000 0xE004.1FFF Embedded Trace Macrocell (ETM) 61 0xE004.2000 0xFFFF.FFFF Reserved - Private Peripheral Bus 2.4.1 Memory Regions, Types and Attributes The memory map and the programming of the MPU split the memory map into regions. Each region has a defined memory type, and some regions have additional memory attributes. The memory type and attributes determine the behavior of accesses to the region. The memory types are: ■ Normal: The processor can re-order transactions for efficiency and perform speculative reads. ■ Device: The processor preserves transaction order relative to other transactions to Device or Strongly Ordered memory. ■ Strongly Ordered: The processor preserves transaction order relative to all other transactions. 84 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller The different ordering requirements for Device and Strongly Ordered memory mean that the memory system can buffer a write to Device memory but must not buffer a write to Strongly Ordered memory. An additional memory attribute is Execute Never (XN), which means the processor prevents instruction accesses. A fault exception is generated only on execution of an instruction executed from an XN region. 2.4.2 Memory System Ordering of Memory Accesses For most memory accesses caused by explicit memory access instructions, the memory system does not guarantee that the order in which the accesses complete matches the program order of the instructions, providing the order does not affect the behavior of the instruction sequence. Normally, if correct program execution depends on two memory accesses completing in program order, software must insert a memory barrier instruction between the memory access instructions (see “Software Ordering of Memory Accesses” on page 86). However, the memory system does guarantee ordering of accesses to Device and Strongly Ordered memory. For two memory access instructions A1 and A2, if both A1 and A2 are accesses to either Device or Strongly Ordered memory, and if A1 occurs before A2 in program order, A1 is always observed before A2. 2.4.3 Behavior of Memory Accesses Table 2-5 on page 85 shows the behavior of accesses to each region in the memory map. See “Memory Regions, Types and Attributes” on page 84 for more information on memory types and the XN attribute. Tiva™ C Series devices may have reserved memory areas within the address ranges shown below (refer to Table 2-4 on page 82 for more information). Table 2-5. Memory Access Behavior Address Range Memory Region Memory Type Execute Never (XN) Description 0x0000.0000 - 0x1FFF.FFFF Code Normal - This executable region is for program code. Data can also be stored here. 0x2000.0000 - 0x3FFF.FFFF SRAM Normal - This executable region is for data. Code can also be stored here. This region includes bit band and bit band alias areas (see Table 2-6 on page 87). 0x4000.0000 - 0x5FFF.FFFF Peripheral Device XN This region includes bit band and bit band alias areas (see Table 2-7 on page 87). 0x6000.0000 - 0x9FFF.FFFF External RAM Normal - This executable region is for data. 0xA000.0000 - 0xDFFF.FFFF External device Device XN This region is for external device memory. 0xE000.0000- 0xE00F.FFFF Private peripheral bus Strongly Ordered XN This region includes the NVIC, system timer, and system control block. 0xE010.0000- 0xFFFF.FFFF Reserved - - - The Code, SRAM, and external RAM regions can hold programs. However, it is recommended that programs always use the Code region because the Cortex-M4F has separate buses that can perform instruction fetches and data accesses simultaneously. The MPU can override the default memory access behavior described in this section. For more information, see “Memory Protection Unit (MPU)” on page 115. The Cortex-M4F prefetches instructions ahead of execution and speculatively prefetches from branch target addresses. June 12, 2014 85 Texas Instruments-Production Data The Cortex-M4F Processor 2.4.4 Software Ordering of Memory Accesses The order of instructions in the program flow does not always guarantee the order of the corresponding memory transactions for the following reasons: ■ The processor can reorder some memory accesses to improve efficiency, providing this does not affect the behavior of the instruction sequence. ■ The processor has multiple bus interfaces. ■ Memory or devices in the memory map have different wait states. ■ Some memory accesses are buffered or speculative. “Memory System Ordering of Memory Accesses” on page 85 describes the cases where the memory system guarantees the order of memory accesses. Otherwise, if the order of memory accesses is critical, software must include memory barrier instructions to force that ordering. The Cortex-M4F has the following memory barrier instructions: ■ The Data Memory Barrier (DMB) instruction ensures that outstanding memory transactions complete before subsequent memory transactions. ■ The Data Synchronization Barrier (DSB) instruction ensures that outstanding memory transactions complete before subsequent instructions execute. ■ The Instruction Synchronization Barrier (ISB) instruction ensures that the effect of all completed memory transactions is recognizable by subsequent instructions. Memory barrier instructions can be used in the following situations: ■ MPU programming – If the MPU settings are changed and the change must be effective on the very next instruction, use a DSB instruction to ensure the effect of the MPU takes place immediately at the end of context switching. – Use an ISB instruction to ensure the new MPU setting takes effect immediately after programming the MPU region or regions, if the MPU configuration code was accessed using a branch or call. If the MPU configuration code is entered using exception mechanisms, then an ISB instruction is not required. ■ Vector table If the program changes an entry in the vector table and then enables the corresponding exception, use a DMB instruction between the operations. The DMB instruction ensures that if the exception is taken immediately after being enabled, the processor uses the new exception vector. ■ Self-modifying code If a program contains self-modifying code, use an ISB instruction immediately after the code modification in the program. The ISB instruction ensures subsequent instruction execution uses the updated program. ■ Memory map switching 86 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller If the system contains a memory map switching mechanism, use a DSB instruction after switching the memory map in the program. The DSB instruction ensures subsequent instruction execution uses the updated memory map. ■ Dynamic exception priority change When an exception priority has to change when the exception is pending or active, use DSB instructions after the change. The change then takes effect on completion of the DSB instruction. Memory accesses to Strongly Ordered memory, such as the System Control Block, do not require the use of DMB instructions. For more information on the memory barrier instructions, see the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A). 2.4.5 Bit-Banding A bit-band region maps each word in a bit-band alias region to a single bit in the bit-band region. The bit-band regions occupy the lowest 1 MB of the SRAM and peripheral memory regions. Accesses to the 32-MB SRAM alias region map to the 1-MB SRAM bit-band region, as shown in Table 2-6 on page 87. Accesses to the 32-MB peripheral alias region map to the 1-MB peripheral bit-band region, as shown in Table 2-7 on page 87. For the specific address range of the bit-band regions, see Table 2-4 on page 82. Note: A word access to the SRAM or the peripheral bit-band alias region maps to a single bit in the SRAM or peripheral bit-band region. A word access to a bit band address results in a word access to the underlying memory, and similarly for halfword and byte accesses. This allows bit band accesses to match the access requirements of the underlying peripheral. Table 2-6. SRAM Memory Bit-Banding Regions Address Range Memory Region Instruction and Data Accesses Start End 0x2000.0000 0x2000.7FFF SRAM bit-band region Direct accesses to this memory range behave as SRAM memory accesses, but this region is also bit addressable through bit-band alias. 0x2200.0000 0x220F.FFFF SRAM bit-band alias Data accesses to this region are remapped to bit band region. A write operation is performed as read-modify-write. Instruction accesses are not remapped. Table 2-7. Peripheral Memory Bit-Banding Regions Address Range Memory Region Instruction and Data Accesses 0x400F.FFFF Peripheral bit-band region Direct accesses to this memory range behave as peripheral memory accesses, but this region is also bit addressable through bit-band alias. 0x43FF.FFFF Peripheral bit-band alias Data accesses to this region are remapped to bit band region. A write operation is performed as read-modify-write. Instruction accesses are not permitted. Start End 0x4000.0000 0x4200.0000 The following formula shows how the alias region maps onto the bit-band region: bit_word_offset = (byte_offset x 32) + (bit_number x 4) June 12, 2014 87 Texas Instruments-Production Data The Cortex-M4F Processor bit_word_addr = bit_band_base + bit_word_offset where: bit_word_offset The position of the target bit in the bit-band memory region. bit_word_addr The address of the word in the alias memory region that maps to the targeted bit. bit_band_base The starting address of the alias region. byte_offset The number of the byte in the bit-band region that contains the targeted bit. bit_number The bit position, 0-7, of the targeted bit. Figure 2-4 on page 89 shows examples of bit-band mapping between the SRAM bit-band alias region and the SRAM bit-band region: ■ The alias word at 0x23FF.FFE0 maps to bit 0 of the bit-band byte at 0x200F.FFFF: 0x23FF.FFE0 = 0x2200.0000 + (0x000F.FFFF*32) + (0*4) ■ The alias word at 0x23FF.FFFC maps to bit 7 of the bit-band byte at 0x200F.FFFF: 0x23FF.FFFC = 0x2200.0000 + (0x000F.FFFF*32) + (7*4) ■ The alias word at 0x2200.0000 maps to bit 0 of the bit-band byte at 0x2000.0000: 0x2200.0000 = 0x2200.0000 + (0*32) + (0*4) ■ The alias word at 0x2200.001C maps to bit 7 of the bit-band byte at 0x2000.0000: 0x2200.001C = 0x2200.0000+ (0*32) + (7*4) 88 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 2-4. Bit-Band Mapping 32-MB Alias Region 0x23FF.FFFC 0x23FF.FFF8 0x23FF.FFF4 0x23FF.FFF0 0x23FF.FFEC 0x23FF.FFE8 0x23FF.FFE4 0x23FF.FFE0 0x2200.001C 0x2200.0018 0x2200.0014 0x2200.0010 0x2200.000C 0x2200.0008 0x2200.0004 0x2200.0000 7 3 1-MB SRAM Bit-Band Region 7 6 5 4 3 2 1 0 7 6 0x200F.FFFF 7 6 5 4 3 2 0x2000.0003 2.4.5.1 5 4 3 2 1 0 7 6 0x200F.FFFE 1 0 7 6 5 4 3 2 5 4 3 2 1 0 6 0x200F.FFFD 1 0 0x2000.0002 7 6 5 4 3 2 0x2000.0001 5 4 2 1 0 1 0 0x200F.FFFC 1 0 7 6 5 4 3 2 0x2000.0000 Directly Accessing an Alias Region Writing to a word in the alias region updates a single bit in the bit-band region. Bit 0 of the value written to a word in the alias region determines the value written to the targeted bit in the bit-band region. Writing a value with bit 0 set writes a 1 to the bit-band bit, and writing a value with bit 0 clear writes a 0 to the bit-band bit. Bits 31:1 of the alias word have no effect on the bit-band bit. Writing 0x01 has the same effect as writing 0xFF. Writing 0x00 has the same effect as writing 0x0E. When reading a word in the alias region, 0x0000.0000 indicates that the targeted bit in the bit-band region is clear and 0x0000.0001 indicates that the targeted bit in the bit-band region is set. 2.4.5.2 Directly Accessing a Bit-Band Region “Behavior of Memory Accesses” on page 85 describes the behavior of direct byte, halfword, or word accesses to the bit-band regions. 2.4.6 Data Storage The processor views memory as a linear collection of bytes numbered in ascending order from zero. For example, bytes 0-3 hold the first stored word, and bytes 4-7 hold the second stored word. Data is stored in little-endian format, with the least-significant byte (lsbyte) of a word stored at the lowest-numbered byte, and the most-significant byte (msbyte) stored at the highest-numbered byte. Figure 2-5 on page 90 illustrates how data is stored. June 12, 2014 89 Texas Instruments-Production Data The Cortex-M4F Processor Figure 2-5. Data Storage Memory 7 Register 0 31 2.4.7 Address A B0 A+1 B1 A+2 B2 A+3 B3 lsbyte 24 23 B3 16 15 B2 8 7 B1 0 B0 msbyte Synchronization Primitives The Cortex-M4F instruction set includes pairs of synchronization primitives which provide a non-blocking mechanism that a thread or process can use to obtain exclusive access to a memory location. Software can use these primitives to perform a guaranteed read-modify-write memory update sequence or for a semaphore mechanism. A pair of synchronization primitives consists of: ■ A Load-Exclusive instruction, which is used to read the value of a memory location and requests exclusive access to that location. ■ A Store-Exclusive instruction, which is used to attempt to write to the same memory location and returns a status bit to a register. If this status bit is clear, it indicates that the thread or process gained exclusive access to the memory and the write succeeds; if this status bit is set, it indicates that the thread or process did not gain exclusive access to the memory and no write was performed. The pairs of Load-Exclusive and Store-Exclusive instructions are: ■ The word instructions LDREX and STREX ■ The halfword instructions LDREXH and STREXH ■ The byte instructions LDREXB and STREXB Software must use a Load-Exclusive instruction with the corresponding Store-Exclusive instruction. To perform an exclusive read-modify-write of a memory location, software must: 1. Use a Load-Exclusive instruction to read the value of the location. 2. Modify the value, as required. 3. Use a Store-Exclusive instruction to attempt to write the new value back to the memory location. 4. Test the returned status bit. If the status bit is clear, the read-modify-write completed successfully. If the status bit is set, no write was performed, which indicates that the value returned at step 1 might be out of date. The software must retry the entire read-modify-write sequence. Software can use the synchronization primitives to implement a semaphore as follows: 90 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 1. Use a Load-Exclusive instruction to read from the semaphore address to check whether the semaphore is free. 2. If the semaphore is free, use a Store-Exclusive to write the claim value to the semaphore address. 3. If the returned status bit from step 2 indicates that the Store-Exclusive succeeded, then the software has claimed the semaphore. However, if the Store-Exclusive failed, another process might have claimed the semaphore after the software performed step 1. The Cortex-M4F includes an exclusive access monitor that tags the fact that the processor has executed a Load-Exclusive instruction. The processor removes its exclusive access tag if: ■ It executes a CLREX instruction. ■ It executes a Store-Exclusive instruction, regardless of whether the write succeeds. ■ An exception occurs, which means the processor can resolve semaphore conflicts between different threads. For more information about the synchronization primitive instructions, see the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A). 2.5 Exception Model The ARM Cortex-M4F processor and the Nested Vectored Interrupt Controller (NVIC) prioritize and handle all exceptions in Handler Mode. The processor state is automatically stored to the stack on an exception and automatically restored from the stack at the end of the Interrupt Service Routine (ISR). The vector is fetched in parallel to the state saving, enabling efficient interrupt entry. The processor supports tail-chaining, which enables back-to-back interrupts to be performed without the overhead of state saving and restoration. Table 2-8 on page 93 lists all exception types. Software can set eight priority levels on seven of these exceptions (system handlers) as well as on 64 interrupts (listed in Table 2-9 on page 94). Priorities on the system handlers are set with the NVIC System Handler Priority n (SYSPRIn) registers. Interrupts are enabled through the NVIC Interrupt Set Enable n (ENn) register and prioritized with the NVIC Interrupt Priority n (PRIn) registers. Priorities can be grouped by splitting priority levels into preemption priorities and subpriorities. All the interrupt registers are described in “Nested Vectored Interrupt Controller (NVIC)” on page 114. Internally, the highest user-programmable priority (0) is treated as fourth priority, after a Reset, Non-Maskable Interrupt (NMI), and a Hard Fault, in that order. Note that 0 is the default priority for all the programmable priorities. Important: After a write to clear an interrupt source, it may take several processor cycles for the NVIC to see the interrupt source deassert. Thus if the interrupt clear is done as the last action in an interrupt handler, it is possible for the interrupt handler to complete while the NVIC sees the interrupt as still asserted, causing the interrupt handler to be re-entered errantly. This situation can be avoided by either clearing the interrupt source at the beginning of the interrupt handler or by performing a read or write after the write to clear the interrupt source (and flush the write buffer). See “Nested Vectored Interrupt Controller (NVIC)” on page 114 for more information on exceptions and interrupts. June 12, 2014 91 Texas Instruments-Production Data The Cortex-M4F Processor 2.5.1 Exception States Each exception is in one of the following states: ■ Inactive. The exception is not active and not pending. ■ Pending. The exception is waiting to be serviced by the processor. An interrupt request from a peripheral or from software can change the state of the corresponding interrupt to pending. ■ Active. An exception that is being serviced by the processor but has not completed. Note: An exception handler can interrupt the execution of another exception handler. In this case, both exceptions are in the active state. ■ Active and Pending. The exception is being serviced by the processor, and there is a pending exception from the same source. 2.5.2 Exception Types The exception types are: ■ Reset. Reset is invoked on power up or a warm reset. The exception model treats reset as a special form of exception. When reset is asserted, the operation of the processor stops, potentially at any point in an instruction. When reset is deasserted, execution restarts from the address provided by the reset entry in the vector table. Execution restarts as privileged execution in Thread mode. ■ NMI. A non-maskable Interrupt (NMI) can be signaled using the NMI signal or triggered by software using the Interrupt Control and State (INTCTRL) register. This exception has the highest priority other than reset. NMI is permanently enabled and has a fixed priority of -2. NMIs cannot be masked or prevented from activation by any other exception or preempted by any exception other than reset. ■ Hard Fault. A hard fault is an exception that occurs because of an error during exception processing, or because an exception cannot be managed by any other exception mechanism. Hard faults have a fixed priority of -1, meaning they have higher priority than any exception with configurable priority. ■ Memory Management Fault. A memory management fault is an exception that occurs because of a memory protection related fault, including access violation and no match. The MPU or the fixed memory protection constraints determine this fault, for both instruction and data memory transactions. This fault is used to abort instruction accesses to Execute Never (XN) memory regions, even if the MPU is disabled. ■ Bus Fault. A bus fault is an exception that occurs because of a memory-related fault for an instruction or data memory transaction such as a prefetch fault or a memory access fault. This fault can be enabled or disabled. ■ Usage Fault. A usage fault is an exception that occurs because of a fault related to instruction execution, such as: – An undefined instruction – An illegal unaligned access – Invalid state on instruction execution 92 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller – An error on exception return An unaligned address on a word or halfword memory access or division by zero can cause a usage fault when the core is properly configured. ■ SVCall. A supervisor call (SVC) is an exception that is triggered by the SVC instruction. In an OS environment, applications can use SVC instructions to access OS kernel functions and device drivers. ■ Debug Monitor. This exception is caused by the debug monitor (when not halting). This exception is only active when enabled. This exception does not activate if it is a lower priority than the current activation. ■ PendSV. PendSV is a pendable, interrupt-driven request for system-level service. In an OS environment, use PendSV for context switching when no other exception is active. PendSV is triggered using the Interrupt Control and State (INTCTRL) register. ■ SysTick. A SysTick exception is an exception that the system timer generates when it reaches zero when it is enabled to generate an interrupt. Software can also generate a SysTick exception using the Interrupt Control and State (INTCTRL) register. In an OS environment, the processor can use this exception as system tick. ■ Interrupt (IRQ). An interrupt, or IRQ, is an exception signaled by a peripheral or generated by a software request and fed through the NVIC (prioritized). All interrupts are asynchronous to instruction execution. In the system, peripherals use interrupts to communicate with the processor. Table 2-9 on page 94 lists the interrupts on the TM4C1231H6PM controller. For an asynchronous exception, other than reset, the processor can execute another instruction between when the exception is triggered and when the processor enters the exception handler. Privileged software can disable the exceptions that Table 2-8 on page 93 shows as having configurable priority (see the SYSHNDCTRL register on page 163 and the DIS0 register on page 134). For more information about hard faults, memory management faults, bus faults, and usage faults, see “Fault Handling” on page 101. Table 2-8. Exception Types Exception Type a Vector Number Priority Vector Address or b Offset - 0 - 0x0000.0000 Stack top is loaded from the first entry of the vector table on reset. Reset 1 -3 (highest) 0x0000.0004 Asynchronous Non-Maskable Interrupt (NMI) 2 -2 0x0000.0008 Asynchronous Hard Fault 3 -1 0x0000.000C - c 0x0000.0010 Synchronous c 0x0000.0014 Synchronous when precise and asynchronous when imprecise c Synchronous Memory Management 4 programmable Bus Fault 5 programmable Usage Fault 6 programmable 0x0000.0018 7-10 - - - Activation c c Reserved SVCall 11 programmable 0x0000.002C Synchronous Debug Monitor 12 programmable 0x0000.0030 Synchronous - 13 - - June 12, 2014 Reserved 93 Texas Instruments-Production Data The Cortex-M4F Processor Table 2-8. Exception Types (continued) Exception Type PendSV SysTick a Vector Number Priority 14 programmable 15 Interrupts Vector Address or b Offset c 0x0000.0038 Asynchronous c 0x0000.003C Asynchronous programmable 16 and above Activation d programmable 0x0000.0040 and above Asynchronous a. 0 is the default priority for all the programmable priorities. b. See “Vector Table” on page 96. c. See SYSPRI1 on page 160. d. See PRIn registers on page 142. Table 2-9. Interrupts Vector Number Interrupt Number (Bit in Interrupt Registers) Vector Address or Offset 0-15 - 0x0000.0000 0x0000.003C 16 0 0x0000.0040 GPIO Port A 17 1 0x0000.0044 GPIO Port B 18 2 0x0000.0048 GPIO Port C 19 3 0x0000.004C GPIO Port D 20 4 0x0000.0050 GPIO Port E 21 5 0x0000.0054 UART0 22 6 0x0000.0058 UART1 23 7 0x0000.005C SSI0 24 8 0x0000.0060 I2C0 25-29 9-13 - 30 14 0x0000.0078 ADC0 Sequence 0 31 15 0x0000.007C ADC0 Sequence 1 32 16 0x0000.0080 ADC0 Sequence 2 33 17 0x0000.0084 ADC0 Sequence 3 34 18 0x0000.0088 Watchdog Timers 0 and 1 35 19 0x0000.008C 16/32-Bit Timer 0A 36 20 0x0000.0090 16/32-Bit Timer 0B 37 21 0x0000.0094 16/32-Bit Timer 1A 38 22 0x0000.0098 16/32-Bit Timer 1B 39 23 0x0000.009C 16/32-Bit Timer 2A 40 24 0x0000.00A0 16/32-Bit Timer 2B 41 25 0x0000.00A4 Analog Comparator 0 42 26 0x0000.00A8 Analog Comparator 1 43 27 - 44 28 0x0000.00B0 System Control 45 29 0x0000.00B4 Flash Memory Control and EEPROM Control GPIO Port F 46 30 0x0000.00B8 47-48 31-32 - 49 33 0x0000.00C4 Description Processor exceptions Reserved Reserved Reserved UART2 94 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 2-9. Interrupts (continued) Vector Number Interrupt Number (Bit in Interrupt Registers) Vector Address or Offset Description 50 34 0x0000.00C8 SSI1 51 35 0x0000.00CC 16/32-Bit Timer 3A 52 36 0x0000.00D0 16/32-Bit Timer 3B 53 37 0x0000.00D4 I2C1 54 38 - 55 39 0x0000.00DC 56-58 40-42 - 59 43 0x0000.00EC 60-61 44-45 - 62 46 0x0000.00F8 µDMA Software 63 47 0x0000.00FC µDMA Error 64 48 0x0000.0100 ADC1 Sequence 0 65 49 0x0000.0104 ADC1 Sequence 1 66 50 0x0000.0108 ADC1 Sequence 2 67 51 0x0000.010C ADC1 Sequence 3 68-72 52-56 - 73 57 0x0000.0124 SSI2 74 58 0x0000.0128 SSI3 75 59 0x0000.012C UART3 76 60 0x0000.0130 UART4 77 61 0x0000.0134 UART5 78 62 0x0000.0138 UART6 Reserved CAN0 Reserved Hibernation Module Reserved Reserved 79 63 0x0000.013C UART7 80-83 64-67 0x0000.0140 0x0000.014C Reserved 84 68 0x0000.0150 I2C2 85 69 0x0000.0154 I2C3 86 70 0x0000.0158 16/32-Bit Timer 4A 87 71 0x0000.015C 16/32-Bit Timer 4B 88-107 72-91 0x0000.0160 0x0000.01AC Reserved 108 92 0x0000.01B0 16/32-Bit Timer 5A 109 93 0x0000.01B4 16/32-Bit Timer 5B 110 94 0x0000.01B8 32/64-Bit Timer 0A 111 95 0x0000.01BC 32/64-Bit Timer 0B 112 96 0x0000.01C0 32/64-Bit Timer 1A 113 97 0x0000.01C4 32/64-Bit Timer 1B 114 98 0x0000.01C8 32/64-Bit Timer 2A 115 99 0x0000.01CC 32/64-Bit Timer 2B 116 100 0x0000.01D0 32/64-Bit Timer 3A 117 101 0x0000.01D4 32/64-Bit Timer 3B 118 102 0x0000.01D8 32/64-Bit Timer 4A June 12, 2014 95 Texas Instruments-Production Data The Cortex-M4F Processor Table 2-9. Interrupts (continued) 2.5.3 Vector Number Interrupt Number (Bit in Interrupt Registers) Vector Address or Offset Description 119 103 0x0000.01DC 32/64-Bit Timer 4B 120 104 0x0000.01E0 32/64-Bit Timer 5A 121 105 0x0000.01E4 32/64-Bit Timer 5B 122 106 0x0000.01E8 System Exception (imprecise) 123-154 107-138 - Reserved Exception Handlers The processor handles exceptions using: ■ Interrupt Service Routines (ISRs). Interrupts (IRQx) are the exceptions handled by ISRs. ■ Fault Handlers. Hard fault, memory management fault, usage fault, and bus fault are fault exceptions handled by the fault handlers. ■ System Handlers. NMI, PendSV, SVCall, SysTick, and the fault exceptions are all system exceptions that are handled by system handlers. 2.5.4 Vector Table The vector table contains the reset value of the stack pointer and the start addresses, also called exception vectors, for all exception handlers. The vector table is constructed using the vector address or offset shown in Table 2-8 on page 93. Figure 2-6 on page 97 shows the order of the exception vectors in the vector table. The least-significant bit of each vector must be 1, indicating that the exception handler is Thumb code 96 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 2-6. Vector Table Exception number IRQ number 154 138 . . . 18 2 17 1 16 0 15 -1 14 -2 13 Offset 0x0268 . . . 0x004C 0x0048 0x0044 0x0040 0x003C 0x0038 12 11 Vector IRQ131 . . . IRQ2 IRQ1 IRQ0 Systick PendSV Reserved Reserved for Debug -5 10 0x002C 9 SVCall Reserved 8 7 6 -10 5 -11 4 -12 3 -13 2 -14 1 0x0018 0x0014 0x0010 0x000C 0x0008 0x0004 0x0000 Usage fault Bus fault Memory management fault Hard fault NMI Reset Initial SP value On system reset, the vector table is fixed at address 0x0000.0000. Privileged software can write to the Vector Table Offset (VTABLE) register to relocate the vector table start address to a different memory location, in the range 0x0000.0400 to 0x3FFF.FC00 (see “Vector Table” on page 96). Note that when configuring the VTABLE register, the offset must be aligned on a 1024-byte boundary. 2.5.5 Exception Priorities As Table 2-8 on page 93 shows, all exceptions have an associated priority, with a lower priority value indicating a higher priority and configurable priorities for all exceptions except Reset, Hard fault, and NMI. If software does not configure any priorities, then all exceptions with a configurable priority have a priority of 0. For information about configuring exception priorities, see page 160 and page 142. Note: Configurable priority values for the Tiva™ C Series implementation are in the range 0-7. This means that the Reset, Hard fault, and NMI exceptions, with fixed negative priority values, always have higher priority than any other exception. For example, assigning a higher priority value to IRQ[0] and a lower priority value to IRQ[1] means that IRQ[1] has higher priority than IRQ[0]. If both IRQ[1] and IRQ[0] are asserted, IRQ[1] is processed before IRQ[0]. June 12, 2014 97 Texas Instruments-Production Data The Cortex-M4F Processor If multiple pending exceptions have the same priority, the pending exception with the lowest exception number takes precedence. For example, if both IRQ[0] and IRQ[1] are pending and have the same priority, then IRQ[0] is processed before IRQ[1]. When the processor is executing an exception handler, the exception handler is preempted if a higher priority exception occurs. If an exception occurs with the same priority as the exception being handled, the handler is not preempted, irrespective of the exception number. However, the status of the new interrupt changes to pending. 2.5.6 Interrupt Priority Grouping To increase priority control in systems with interrupts, the NVIC supports priority grouping. This grouping divides each interrupt priority register entry into two fields: ■ An upper field that defines the group priority ■ A lower field that defines a subpriority within the group Only the group priority determines preemption of interrupt exceptions. When the processor is executing an interrupt exception handler, another interrupt with the same group priority as the interrupt being handled does not preempt the handler. If multiple pending interrupts have the same group priority, the subpriority field determines the order in which they are processed. If multiple pending interrupts have the same group priority and subpriority, the interrupt with the lowest IRQ number is processed first. For information about splitting the interrupt priority fields into group priority and subpriority, see page 154. 2.5.7 Exception Entry and Return Descriptions of exception handling use the following terms: ■ Preemption. When the processor is executing an exception handler, an exception can preempt the exception handler if its priority is higher than the priority of the exception being handled. See “Interrupt Priority Grouping” on page 98 for more information about preemption by an interrupt. When one exception preempts another, the exceptions are called nested exceptions. See “Exception Entry” on page 99 more information. ■ Return. Return occurs when the exception handler is completed, and there is no pending exception with sufficient priority to be serviced and the completed exception handler was not handling a late-arriving exception. The processor pops the stack and restores the processor state to the state it had before the interrupt occurred. See “Exception Return” on page 100 for more information. ■ Tail-Chaining. This mechanism speeds up exception servicing. On completion of an exception handler, if there is a pending exception that meets the requirements for exception entry, the stack pop is skipped and control transfers to the new exception handler. ■ Late-Arriving. This mechanism speeds up preemption. If a higher priority exception occurs during state saving for a previous exception, the processor switches to handle the higher priority exception and initiates the vector fetch for that exception. State saving is not affected by late arrival because the state saved is the same for both exceptions. Therefore, the state saving continues uninterrupted. The processor can accept a late arriving exception until the first instruction of the exception handler of the original exception enters the execute stage of the processor. On 98 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller return from the exception handler of the late-arriving exception, the normal tail-chaining rules apply. 2.5.7.1 Exception Entry Exception entry occurs when there is a pending exception with sufficient priority and either the processor is in Thread mode or the new exception is of higher priority than the exception being handled, in which case the new exception preempts the original exception. When one exception preempts another, the exceptions are nested. Sufficient priority means the exception has more priority than any limits set by the mask registers (see PRIMASK on page 75, FAULTMASK on page 76, and BASEPRI on page 77). An exception with less priority than this is pending but is not handled by the processor. When the processor takes an exception, unless the exception is a tail-chained or a late-arriving exception, the processor pushes information onto the current stack. This operation is referred to as stacking and the structure of eight data words is referred to as stack frame. When using floating-point routines, the Cortex-M4F processor automatically stacks the architected floating-point state on exception entry. Figure 2-7 on page 100 shows the Cortex-M4F stack frame layout when floating-point state is preserved on the stack as the result of an interrupt or an exception. Note: Where stack space for floating-point state is not allocated, the stack frame is the same as that of ARMv7-M implementations without an FPU. Figure 2-7 on page 100 shows this stack frame also. June 12, 2014 99 Texas Instruments-Production Data The Cortex-M4F Processor Figure 2-7. Exception Stack Frame ... {aligner} FPSCR S15 S14 S13 S12 S11 S10 S9 S8 S7 S6 S5 S4 S3 S2 S1 S0 xPSR PC LR R12 R3 R2 R1 R0 Exception frame with floating-point storage Pre-IRQ top of stack Decreasing memory address IRQ top of stack ... {aligner} xPSR PC LR R12 R3 R2 R1 R0 Pre-IRQ top of stack IRQ top of stack Exception frame without floating-point storage Immediately after stacking, the stack pointer indicates the lowest address in the stack frame. The stack frame includes the return address, which is the address of the next instruction in the interrupted program. This value is restored to the PC at exception return so that the interrupted program resumes. In parallel with the stacking operation, the processor performs a vector fetch that reads the exception handler start address from the vector table. When stacking is complete, the processor starts executing the exception handler. At the same time, the processor writes an EXC_RETURN value to the LR, indicating which stack pointer corresponds to the stack frame and what operation mode the processor was in before the entry occurred. If no higher-priority exception occurs during exception entry, the processor starts executing the exception handler and automatically changes the status of the corresponding pending interrupt to active. If another higher-priority exception occurs during exception entry, known as late arrival, the processor starts executing the exception handler for this exception and does not change the pending status of the earlier exception. 2.5.7.2 Exception Return Exception return occurs when the processor is in Handler mode and executes one of the following instructions to load the EXC_RETURN value into the PC: 100 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller ■ An LDM or POP instruction that loads the PC ■ A BX instruction using any register ■ An LDR instruction with the PC as the destination EXC_RETURN is the value loaded into the LR on exception entry. The exception mechanism relies on this value to detect when the processor has completed an exception handler. The lowest five bits of this value provide information on the return stack and processor mode. Table 2-10 on page 101 shows the EXC_RETURN values with a description of the exception return behavior. EXC_RETURN bits 31:5 are all set. When this value is loaded into the PC, it indicates to the processor that the exception is complete, and the processor initiates the appropriate exception return sequence. Table 2-10. Exception Return Behavior EXC_RETURN[31:0] Description 0xFFFF.FFE0 Reserved 0xFFFF.FFE1 Return to Handler mode. Exception return uses floating-point state from MSP. Execution uses MSP after return. 0xFFFF.FFE2 - 0xFFFF.FFE8 Reserved 0xFFFF.FFE9 Return to Thread mode. Exception return uses floating-point state from MSP. Execution uses MSP after return. 0xFFFF.FFEA - 0xFFFF.FFEC Reserved 0xFFFF.FFED Return to Thread mode. Exception return uses floating-point state from PSP. Execution uses PSP after return. 0xFFFF.FFEE - 0xFFFF.FFF0 Reserved 0xFFFF.FFF1 Return to Handler mode. Exception return uses non-floating-point state from MSP. Execution uses MSP after return. 0xFFFF.FFF2 - 0xFFFF.FFF8 Reserved 0xFFFF.FFF9 Return to Thread mode. Exception return uses non-floating-point state from MSP. Execution uses MSP after return. 0xFFFF.FFFA - 0xFFFF.FFFC Reserved 0xFFFF.FFFD Return to Thread mode. Exception return uses non-floating-point state from PSP. Execution uses PSP after return. 0xFFFF.FFFE - 0xFFFF.FFFF 2.6 Reserved Fault Handling Faults are a subset of the exceptions (see “Exception Model” on page 91). The following conditions generate a fault: ■ A bus error on an instruction fetch or vector table load or a data access. June 12, 2014 101 Texas Instruments-Production Data The Cortex-M4F Processor ■ An internally detected error such as an undefined instruction or an attempt to change state with a BX instruction. ■ Attempting to execute an instruction from a memory region marked as Non-Executable (XN). ■ An MPU fault because of a privilege violation or an attempt to access an unmanaged region. 2.6.1 Fault Types Table 2-11 on page 102 shows the types of fault, the handler used for the fault, the corresponding fault status register, and the register bit that indicates the fault has occurred. See page 167 for more information about the fault status registers. Table 2-11. Faults Fault Handler Fault Status Register Bit Name Bus error on a vector read Hard fault Hard Fault Status (HFAULTSTAT) VECT Fault escalated to a hard fault Hard fault Hard Fault Status (HFAULTSTAT) FORCED MPU or default memory mismatch on instruction access Memory management fault Memory Management Fault Status (MFAULTSTAT) IERR MPU or default memory mismatch on data access Memory management fault Memory Management Fault Status (MFAULTSTAT) DERR MPU or default memory mismatch on exception stacking Memory management fault Memory Management Fault Status (MFAULTSTAT) MSTKE MPU or default memory mismatch on exception unstacking Memory management fault Memory Management Fault Status (MFAULTSTAT) MUSTKE MPU or default memory mismatch during lazy floating-point state preservation Memory management fault Memory Management Fault Status (MFAULTSTAT) MLSPERR Bus error during exception stacking Bus fault Bus Fault Status (BFAULTSTAT) BSTKE Bus error during exception unstacking Bus fault Bus Fault Status (BFAULTSTAT) BUSTKE Bus error during instruction prefetch Bus fault Bus Fault Status (BFAULTSTAT) IBUS Bus error during lazy floating-point state Bus fault preservation Bus Fault Status (BFAULTSTAT) BLSPE Precise data bus error Bus fault Bus Fault Status (BFAULTSTAT) PRECISE Imprecise data bus error Bus fault Bus Fault Status (BFAULTSTAT) IMPRE Attempt to access a coprocessor Usage fault Usage Fault Status (UFAULTSTAT) NOCP Undefined instruction Usage fault Usage Fault Status (UFAULTSTAT) UNDEF Attempt to enter an invalid instruction b set state Usage fault Usage Fault Status (UFAULTSTAT) INVSTAT Invalid EXC_RETURN value Usage fault Usage Fault Status (UFAULTSTAT) INVPC Illegal unaligned load or store Usage fault Usage Fault Status (UFAULTSTAT) UNALIGN Divide by 0 Usage fault Usage Fault Status (UFAULTSTAT) DIV0 a a. Occurs on an access to an XN region even if the MPU is disabled. b. Attempting to use an instruction set other than the Thumb instruction set, or returning to a non load-store-multiply instruction with ICI continuation. 2.6.2 Fault Escalation and Hard Faults All fault exceptions except for hard fault have configurable exception priority (see SYSPRI1 on page 160). Software can disable execution of the handlers for these faults (see SYSHNDCTRL on page 163). 102 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Usually, the exception priority, together with the values of the exception mask registers, determines whether the processor enters the fault handler, and whether a fault handler can preempt another fault handler as described in “Exception Model” on page 91. In some situations, a fault with configurable priority is treated as a hard fault. This process is called priority escalation, and the fault is described as escalated to hard fault. Escalation to hard fault occurs when: ■ A fault handler causes the same kind of fault as the one it is servicing. This escalation to hard fault occurs because a fault handler cannot preempt itself because it must have the same priority as the current priority level. ■ A fault handler causes a fault with the same or lower priority as the fault it is servicing. This situation happens because the handler for the new fault cannot preempt the currently executing fault handler. ■ An exception handler causes a fault for which the priority is the same as or lower than the currently executing exception. ■ A fault occurs and the handler for that fault is not enabled. If a bus fault occurs during a stack push when entering a bus fault handler, the bus fault does not escalate to a hard fault. Thus if a corrupted stack causes a fault, the fault handler executes even though the stack push for the handler failed. The fault handler operates but the stack contents are corrupted. Note: 2.6.3 Only Reset and NMI can preempt the fixed priority hard fault. A hard fault can preempt any exception other than Reset, NMI, or another hard fault. Fault Status Registers and Fault Address Registers The fault status registers indicate the cause of a fault. For bus faults and memory management faults, the fault address register indicates the address accessed by the operation that caused the fault, as shown in Table 2-12 on page 103. Table 2-12. Fault Status and Fault Address Registers Handler Status Register Name Address Register Name Register Description Hard fault Hard Fault Status (HFAULTSTAT) - page 173 Memory management Memory Management Fault Status fault (MFAULTSTAT) Memory Management Fault Address (MMADDR) page 167 Bus fault Bus Fault Address (FAULTADDR) page 167 - page 167 Bus Fault Status (BFAULTSTAT) Usage fault 2.6.4 Usage Fault Status (UFAULTSTAT) page 174 page 175 Lockup The processor enters a lockup state if a hard fault occurs when executing the NMI or hard fault handlers. When the processor is in the lockup state, it does not execute any instructions. The processor remains in lockup state until it is reset, an NMI occurs, or it is halted by a debugger. Note: If the lockup state occurs from the NMI handler, a subsequent NMI does not cause the processor to leave the lockup state. June 12, 2014 103 Texas Instruments-Production Data The Cortex-M4F Processor 2.7 Power Management The Cortex-M4F processor sleep modes reduce power consumption: ■ Sleep mode stops the processor clock. ■ Deep-sleep mode stops the system clock and switches off the PLL and Flash memory. The SLEEPDEEP bit of the System Control (SYSCTRL) register selects which sleep mode is used (see page 156). For more information about the behavior of the sleep modes, see “System Control” on page 215. This section describes the mechanisms for entering sleep mode and the conditions for waking up from sleep mode, both of which apply to Sleep mode and Deep-sleep mode. 2.7.1 Entering Sleep Modes This section describes the mechanisms software can use to put the processor into one of the sleep modes. The system can generate spurious wake-up events, for example a debug operation wakes up the processor. Therefore, software must be able to put the processor back into sleep mode after such an event. A program might have an idle loop to put the processor back to sleep mode. 2.7.1.1 Wait for Interrupt The wait for interrupt instruction, WFI, causes immediate entry to sleep mode unless the wake-up condition is true (see “Wake Up from WFI or Sleep-on-Exit” on page 105). When the processor executes a WFI instruction, it stops executing instructions and enters sleep mode. See the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) for more information. 2.7.1.2 Wait for Event The wait for event instruction, WFE, causes entry to sleep mode conditional on the value of a one-bit event register. When the processor executes a WFE instruction, it checks the event register. If the register is 0, the processor stops executing instructions and enters sleep mode. If the register is 1, the processor clears the register and continues executing instructions without entering sleep mode. If the event register is 1, the processor must not enter sleep mode on execution of a WFE instruction. Typically, this situation occurs if an SEV instruction has been executed. Software cannot access this register directly. See the Cortex™-M4 instruction set chapter in the ARM® Cortex™-M4 Devices Generic User Guide (literature number ARM DUI 0553A) for more information. 2.7.1.3 Sleep-on-Exit If the SLEEPEXIT bit of the SYSCTRL register is set, when the processor completes the execution of all exception handlers, it returns to Thread mode and immediately enters sleep mode. This mechanism can be used in applications that only require the processor to run when an exception occurs. 2.7.2 Wake Up from Sleep Mode The conditions for the processor to wake up depend on the mechanism that caused it to enter sleep mode. 104 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 2.7.2.1 Wake Up from WFI or Sleep-on-Exit Normally, the processor wakes up only when the NVIC detects an exception with sufficient priority to cause exception entry. Some embedded systems might have to execute system restore tasks after the processor wakes up and before executing an interrupt handler. Entry to the interrupt handler can be delayed by setting the PRIMASK bit and clearing the FAULTMASK bit. If an interrupt arrives that is enabled and has a higher priority than current exception priority, the processor wakes up but does not execute the interrupt handler until the processor clears PRIMASK. For more information about PRIMASK and FAULTMASK, see page 75 and page 76. 2.7.2.2 Wake Up from WFE The processor wakes up if it detects an exception with sufficient priority to cause exception entry. In addition, if the SEVONPEND bit in the SYSCTRL register is set, any new pending interrupt triggers an event and wakes up the processor, even if the interrupt is disabled or has insufficient priority to cause exception entry. For more information about SYSCTRL, see page 156. 2.8 Instruction Set Summary The processor implements a version of the Thumb instruction set. Table 2-13 on page 105 lists the supported instructions. Note: In Table 2-13 on page 105: ■ ■ ■ ■ ■ Angle brackets, , enclose alternative forms of the operand Braces, {}, enclose optional operands The Operands column is not exhaustive Op2 is a flexible second operand that can be either a register or a constant Most instructions can use an optional condition code suffix For more information on the instructions and operands, see the instruction descriptions in the ARM® Cortex™-M4 Technical Reference Manual. Table 2-13. Cortex-M4F Instruction Summary Mnemonic Operands Brief Description Flags ADC, ADCS {Rd,} Rn, Op2 Add with carry N,Z,C,V ADD, ADDS {Rd,} Rn, Op2 Add N,Z,C,V ADD, ADDW {Rd,} Rn , #imm12 Add - ADR Rd, label Load PC-relative address - AND, ANDS {Rd,} Rn, Op2 Logical AND N,Z,C ASR, ASRS Rd, Rm, Arithmetic shift right N,Z,C B label Branch - BFC Rd, #lsb, #width Bit field clear - BFI Rd, Rn, #lsb, #width Bit field insert - BIC, BICS {Rd,} Rn, Op2 Bit clear N,Z,C BKPT #imm Breakpoint - BL label Branch with link - BLX Rm Branch indirect with link - BX Rm Branch indirect - CBNZ Rn, label Compare and branch if non-zero - June 12, 2014 105 Texas Instruments-Production Data The Cortex-M4F Processor Table 2-13. Cortex-M4F Instruction Summary (continued) Mnemonic Operands Brief Description Flags CBZ Rn, label Compare and branch if zero - CLREX - Clear exclusive - CLZ Rd, Rm Count leading zeros - CMN Rn, Op2 Compare negative N,Z,C,V CMP Rn, Op2 Compare N,Z,C,V CPSID i Change processor state, disable interrupts - CPSIE i Change processor state, enable interrupts - DMB - Data memory barrier - DSB - Data synchronization barrier - EOR, EORS {Rd,} Rn, Op2 Exclusive OR N,Z,C ISB - Instruction synchronization barrier - IT - If-Then condition block - LDM Rn{!}, reglist Load multiple registers, increment after - LDMDB, LDMEA Rn{!}, reglist Load multiple registers, decrement before LDMFD, LDMIA Rn{!}, reglist Load multiple registers, increment after - LDR Rt, [Rn, #offset] Load register with word - LDRB, LDRBT Rt, [Rn, #offset] Load register with byte - LDRD Rt, Rt2, [Rn, #offset] Load register with two bytes - LDREX Rt, [Rn, #offset] Load register exclusive - LDREXB Rt, [Rn] Load register exclusive with byte - LDREXH Rt, [Rn] Load register exclusive with halfword - LDRH, LDRHT Rt, [Rn, #offset] Load register with halfword - LDRSB, LDRSBT Rt, [Rn, #offset] Load register with signed byte - LDRSH, LDRSHT Rt, [Rn, #offset] Load register with signed halfword - LDRT Rt, [Rn, #offset] Load register with word - LSL, LSLS Rd, Rm, Logical shift left N,Z,C LSR, LSRS Rd, Rm, Logical shift right N,Z,C MLA Rd, Rn, Rm, Ra Multiply with accumulate, 32-bit result - MLS Rd, Rn, Rm, Ra Multiply and subtract, 32-bit result - MOV, MOVS Rd, Op2 Move N,Z,C MOV, MOVW Rd, #imm16 Move 16-bit constant N,Z,C MOVT Rd, #imm16 Move top - MRS Rd, spec_reg Move from special register to general register - MSR spec_reg, Rm Move from general register to special register N,Z,C,V MUL, MULS {Rd,} Rn, Rm Multiply, 32-bit result N,Z MVN, MVNS Rd, Op2 Move NOT N,Z,C NOP - No operation - ORN, ORNS {Rd,} Rn, Op2 Logical OR NOT N,Z,C 106 - June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 2-13. Cortex-M4F Instruction Summary (continued) Mnemonic Operands Brief Description Flags ORR, ORRS {Rd,} Rn, Op2 Logical OR N,Z,C PKHTB, PKHBT {Rd,} Rn, Rm, Op2 Pack halfword - POP reglist Pop registers from stack - PUSH reglist Push registers onto stack - QADD {Rd,} Rn, Rm Saturating add Q QADD16 {Rd,} Rn, Rm Saturating add 16 - QADD8 {Rd,} Rn, Rm Saturating add 8 - QASX {Rd,} Rn, Rm Saturating add and subtract with exchange - QDADD {Rd,} Rn, Rm Saturating double and add Q QDSUB {Rd,} Rn, Rm Saturating double and subtract Q QSAX {Rd,} Rn, Rm Saturating subtract and add with exchange - QSUB {Rd,} Rn, Rm Saturating subtract Q QSUB16 {Rd,} Rn, Rm Saturating subtract 16 - QSUB8 {Rd,} Rn, Rm Saturating subtract 8 - RBIT Rd, Rn Reverse bits - REV Rd, Rn Reverse byte order in a word - REV16 Rd, Rn Reverse byte order in each halfword - REVSH Rd, Rn Reverse byte order in bottom halfword and sign extend - ROR, RORS Rd, Rm, Rotate right N,Z,C RRX, RRXS Rd, Rm Rotate right with extend N,Z,C RSB, RSBS {Rd,} Rn, Op2 Reverse subtract N,Z,C,V SADD16 {Rd,} Rn, Rm Signed add 16 GE SADD8 {Rd,} Rn, Rm Signed add 8 GE SASX {Rd,} Rn, Rm Signed add and subtract with exchange GE SBC, SBCS {Rd,} Rn, Op2 Subtract with carry N,Z,C,V SBFX Rd, Rn, #lsb, #width Signed bit field extract - SDIV {Rd,} Rn, Rm Signed divide - SEL {Rd,} Rn, Rm Select bytes - SEV - Send event - SHADD16 {Rd,} Rn, Rm Signed halving add 16 - SHADD8 {Rd,} Rn, Rm Signed halving add 8 - SHASX {Rd,} Rn, Rm Signed halving add and subtract with exchange - SHSAX {Rd,} Rn, Rm Signed halving add and subtract with exchange - SHSUB16 {Rd,} Rn, Rm Signed halving subtract 16 - SHSUB8 {Rd,} Rn, Rm Signed halving subtract 8 - June 12, 2014 107 Texas Instruments-Production Data The Cortex-M4F Processor Table 2-13. Cortex-M4F Instruction Summary (continued) Mnemonic Operands Brief Description Flags SMLABB, Rd, Rn, Rm, Ra Signed multiply accumulate long (halfwords) Q Rd, Rn, Rm, Ra Signed multiply accumulate dual Q SMLAL RdLo, RdHi, Rn, Rm Signed multiply with accumulate (32x32+64), 64-bit result - SMLALBB, RdLo, RdHi, Rn, Rm Signed multiply accumulate long (halfwords) - SMLALD, SMLALDX RdLo, RdHi, Rn, Rm Signed multiply accumulate long dual - SMLAWB,SMLAWT Rd, Rn, Rm, Ra Signed multiply accumulate, word by halfword Q SMLSD Rd, Rn, Rm, Ra Signed multiply subtract dual Q RdLo, RdHi, Rn, Rm Signed multiply subtract long dual SMMLA Rd, Rn, Rm, Ra Signed most significant word multiply accumulate - SMMLS, Rd, Rn, Rm, Ra Signed most significant word multiply subtract - {Rd,} Rn, Rm Signed most significant word multiply - {Rd,} Rn, Rm Signed dual multiply add Q {Rd,} Rn, Rm Signed multiply halfwords - SMULL RdLo, RdHi, Rn, Rm Signed multiply (32x32), 64-bit result - SMULWB, {Rd,} Rn, Rm Signed multiply by halfword - {Rd,} Rn, Rm Signed dual multiply subtract - SSAT Rd, #n, Rm {,shift #s} Signed saturate Q SSAT16 Rd, #n, Rm Signed saturate 16 Q SSAX {Rd,} Rn, Rm Saturating subtract and add with exchange GE SSUB16 {Rd,} Rn, Rm Signed subtract 16 - SSUB8 {Rd,} Rn, Rm Signed subtract 8 - STM Rn{!}, reglist Store multiple registers, increment after - SMLABT, SMLATB, SMLATT SMLAD, SMLADX SMLALBT, SMLALTB, SMLALTT SMLSDX SMLSLD SMLSLDX SMMLR SMMUL, SMMULR SMUAD SMUADX SMULBB, SMULBT, SMULTB, SMULTT SMULWT SMUSD, SMUSDX 108 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 2-13. Cortex-M4F Instruction Summary (continued) Mnemonic Operands Brief Description Flags STMDB, STMEA Rn{!}, reglist Store multiple registers, decrement before - STMFD, STMIA Rn{!}, reglist Store multiple registers, increment after - STR Rt, [Rn {, #offset}] Store register word - STRB, STRBT Rt, [Rn {, #offset}] Store register byte - STRD Rt, Rt2, [Rn {, #offset}] Store register two words - STREX Rt, Rt, [Rn {, #offset}] Store register exclusive - STREXB Rd, Rt, [Rn] Store register exclusive byte - STREXH Rd, Rt, [Rn] Store register exclusive halfword - STRH, STRHT Rt, [Rn {, #offset}] Store register halfword - STRSB, STRSBT Rt, [Rn {, #offset}] Store register signed byte - STRSH, STRSHT Rt, [Rn {, #offset}] Store register signed halfword - STRT Rt, [Rn {, #offset}] Store register word - SUB, SUBS {Rd,} Rn, Op2 Subtract N,Z,C,V SUB, SUBW {Rd,} Rn, #imm12 Subtract 12-bit constant N,Z,C,V SVC #imm Supervisor call - SXTAB {Rd,} Rn, Rm, {,ROR #} Extend 8 bits to 32 and add - SXTAB16 {Rd,} Rn, Rm,{,ROR #} Dual extend 8 bits to 16 and add - SXTAH {Rd,} Rn, Rm,{,ROR #} Extend 16 bits to 32 and add - SXTB16 {Rd,} Rm {,ROR #n} Signed extend byte 16 - SXTB {Rd,} Rm {,ROR #n} Sign extend a byte - SXTH {Rd,} Rm {,ROR #n} Sign extend a halfword - TBB [Rn, Rm] Table branch byte - TBH [Rn, Rm, LSL #1] Table branch halfword - TEQ Rn, Op2 Test equivalence N,Z,C TST Rn, Op2 Test N,Z,C UADD16 {Rd,} Rn, Rm Unsigned add 16 GE UADD8 {Rd,} Rn, Rm Unsigned add 8 GE UASX {Rd,} Rn, Rm Unsigned add and subtract with exchange GE UHADD16 {Rd,} Rn, Rm Unsigned halving add 16 - UHADD8 {Rd,} Rn, Rm Unsigned halving add 8 - UHASX {Rd,} Rn, Rm Unsigned halving add and subtract with exchange UHSAX {Rd,} Rn, Rm Unsigned halving subtract and add with exchange UHSUB16 {Rd,} Rn, Rm Unsigned halving subtract 16 - UHSUB8 {Rd,} Rn, Rm Unsigned halving subtract 8 - UBFX Rd, Rn, #lsb, #width Unsigned bit field extract - UDIV {Rd,} Rn, Rm Unsigned divide - UMAAL RdLo, RdHi, Rn, Rm Unsigned multiply accumulate accumulate long (32x32+64), 64-bit result - June 12, 2014 109 Texas Instruments-Production Data The Cortex-M4F Processor Table 2-13. Cortex-M4F Instruction Summary (continued) Mnemonic Operands Brief Description Flags UMLAL RdLo, RdHi, Rn, Rm Unsigned multiply with accumulate (32x32+32+32), 64-bit result - UMULL RdLo, RdHi, Rn, Rm Unsigned multiply (32x 2), 64-bit result - UQADD16 {Rd,} Rn, Rm Unsigned Saturating Add 16 - UQADD8 {Rd,} Rn, Rm Unsigned Saturating Add 8 - UQASX {Rd,} Rn, Rm Unsigned Saturating Add and Subtract with Exchange UQSAX {Rd,} Rn, Rm Unsigned Saturating Subtract and Add with Exchange UQSUB16 {Rd,} Rn, Rm Unsigned Saturating Subtract 16 - UQSUB8 {Rd,} Rn, Rm Unsigned Saturating Subtract 8 - USAD8 {Rd,} Rn, Rm Unsigned Sum of Absolute Differences - USADA8 {Rd,} Rn, Rm, Ra Unsigned Sum of Absolute Differences and Accumulate USAT Rd, #n, Rm {,shift #s} Unsigned Saturate Q USAT16 Rd, #n, Rm Unsigned Saturate 16 Q USAX {Rd,} Rn, Rm Unsigned Subtract and add with Exchange GE USUB16 {Rd,} Rn, Rm Unsigned Subtract 16 GE USUB8 {Rd,} Rn, Rm Unsigned Subtract 8 GE UXTAB {Rd,} Rn, Rm, {,ROR #} Rotate, extend 8 bits to 32 and Add - UXTAB16 {Rd,} Rn, Rm, {,ROR #} Rotate, dual extend 8 bits to 16 and Add - UXTAH {Rd,} Rn, Rm, {,ROR #} Rotate, unsigned extend and Add Halfword - UXTB {Rd,} Rm, {,ROR #n} Zero extend a Byte - UXTB16 {Rd,} Rm, {,ROR #n} Unsigned Extend Byte 16 - UXTH {Rd,} Rm, {,ROR #n} Zero extend a Halfword - VABS.F32 Sd, Sm Floating-point Absolute - VADD.F32 {Sd,} Sn, Sm Floating-point Add - VCMP.F32 Sd, Compare two floating-point registers, or FPSCR one floating-point register and zero VCMPE.F32 Sd, Compare two floating-point registers, or FPSCR one floating-point register and zero with Invalid Operation check VCVT.S32.F32 Sd, Sm Convert between floating-point and integer VCVT.S16.F32 Sd, Sd, #fbits Convert between floating-point and fixed point VCVTR.S32.F32 Sd, Sm Convert between floating-point and integer with rounding - VCVT.F32.F16 Sd, Sm Converts half-precision value to single-precision - VCVTT.F32.F16 Sd, Sm Converts single-precision register to half-precision - VDIV.F32 {Sd,} Sn, Sm Floating-point Divide - VFMA.F32 {Sd,} Sn, Sm Floating-point Fused Multiply Accumulate - 110 - June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 2-13. Cortex-M4F Instruction Summary (continued) Mnemonic Operands Brief Description Flags VFNMA.F32 {Sd,} Sn, Sm Floating-point Fused Negate Multiply Accumulate - VFMS.F32 {Sd,} Sn, Sm Floating-point Fused Multiply Subtract - VFNMS.F32 {Sd,} Sn, Sm Floating-point Fused Negate Multiply Subtract - VLDM.F Rn{!}, list Load Multiple extension registers - VLDR.F , [Rn] Load an extension register from memory - VLMA.F32 {Sd,} Sn, Sm Floating-point Multiply Accumulate - VLMS.F32 {Sd,} Sn, Sm Floating-point Multiply Subtract - VMOV.F32 Sd, #imm Floating-point Move immediate - VMOV Sd, Sm Floating-point Move register - VMOV Sn, Rt Copy ARM core register to single precision - VMOV Sm, Sm1, Rt, Rt2 Copy 2 ARM core registers to 2 single precision - VMOV Dd[x], Rt Copy ARM core register to scalar - VMOV Rt, Dn[x] Copy scalar to ARM core register - VMRS Rt, FPSCR Move FPSCR to ARM core register or APSR N,Z,C,V VMSR FPSCR, Rt Move to FPSCR from ARM Core register FPSCR VMUL.F32 {Sd,} Sn, Sm Floating-point Multiply - VNEG.F32 Sd, Sm Floating-point Negate - VNMLA.F32 {Sd,} Sn, Sm Floating-point Multiply and Add - VNMLS.F32 {Sd,} Sn, Sm Floating-point Multiply and Subtract - VNMUL {Sd,} Sn, Sm Floating-point Multiply - VPOP list Pop extension registers - VPUSH list Push extension registers - VSQRT.F32 Sd, Sm Calculates floating-point Square Root - VSTM Rn{!}, list Floating-point register Store Multiple - VSTR.F3 Sd, [Rn] Stores an extension register to memory - VSUB.F {Sd,} Sn, Sm Floating-point Subtract - WFE - Wait for event - WFI - Wait for interrupt - June 12, 2014 111 Texas Instruments-Production Data Cortex-M4 Peripherals 3 Cortex-M4 Peripherals This chapter provides information on the Tiva™ C Series implementation of the Cortex-M4 processor peripherals, including: ■ SysTick (see page 113) Provides a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. ■ Nested Vectored Interrupt Controller (NVIC) (see page 114) – Facilitates low-latency exception and interrupt handling – Controls power management – Implements system control registers ■ System Control Block (SCB) (see page 115) Provides system implementation information and system control, including configuration, control, and reporting of system exceptions. ■ Memory Protection Unit (MPU) (see page 115) Supports the standard ARMv7 Protected Memory System Architecture (PMSA) model. The MPU provides full support for protection regions, overlapping protection regions, access permissions, and exporting memory attributes to the system. ■ Floating-Point Unit (FPU) (see page 120) Fully supports single-precision add, subtract, multiply, divide, multiply and accumulate, and square root operations. It also provides conversions between fixed-point and floating-point data formats, and floating-point constant instructions. Table 3-1 on page 112 shows the address map of the Private Peripheral Bus (PPB). Some peripheral register regions are split into two address regions, as indicated by two addresses listed. Table 3-1. Core Peripheral Register Regions Address Core Peripheral Description (see page ...) 0xE000.E010-0xE000.E01F System Timer 113 0xE000.E100-0xE000.E4EF Nested Vectored Interrupt Controller 114 System Control Block 115 0xE000.ED90-0xE000.EDB8 Memory Protection Unit 115 0xE000.EF30-0xE000.EF44 Floating Point Unit 120 0xE000.EF00-0xE000.EF03 0xE000.E008-0xE000.E00F 0xE000.ED00-0xE000.ED3F 3.1 Functional Description This chapter provides information on the Tiva™ C Series implementation of the Cortex-M4 processor peripherals: SysTick, NVIC, SCB, MPU, FPU. 112 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 3.1.1 System Timer (SysTick) Cortex-M4 includes an integrated system timer, SysTick, which provides a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter can be used in several different ways, for example as: ■ An RTOS tick timer that fires at a programmable rate (for example, 100 Hz) and invokes a SysTick routine. ■ A high-speed alarm timer using the system clock. ■ A variable rate alarm or signal timer—the duration is range-dependent on the reference clock used and the dynamic range of the counter. ■ A simple counter used to measure time to completion and time used. ■ An internal clock source control based on missing/meeting durations. The COUNT bit in the STCTRL control and status register can be used to determine if an action completed within a set duration, as part of a dynamic clock management control loop. The timer consists of three registers: ■ SysTick Control and Status (STCTRL): A control and status counter to configure its clock, enable the counter, enable the SysTick interrupt, and determine counter status. ■ SysTick Reload Value (STRELOAD): The reload value for the counter, used to provide the counter's wrap value. ■ SysTick Current Value (STCURRENT): The current value of the counter. When enabled, the timer counts down on each clock from the reload value to zero, reloads (wraps) to the value in the STRELOAD register on the next clock edge, then decrements on subsequent clocks. Clearing the STRELOAD register disables the counter on the next wrap. When the counter reaches zero, the COUNT status bit is set. The COUNT bit clears on reads. Writing to the STCURRENT register clears the register and the COUNT status bit. The write does not trigger the SysTick exception logic. On a read, the current value is the value of the register at the time the register is accessed. The SysTick counter runs on either the system clock or the precision internal oscillator (PIOSC) divided by 4. If this clock signal is stopped for low power mode, the SysTick counter stops. SysTick can be kept running during Deep-sleep mode by setting the CLK_SRC bit in the SysTick Control and Status Register (STCTRL) register and ensuring that the PIOSCPD bit in the Deep Sleep Clock Configuration (DSLPCLKCFG) register is clear. Ensure software uses aligned word accesses to access the SysTick registers. The SysTick counter reload and current value are undefined at reset; the correct initialization sequence for the SysTick counter is: 1. Program the value in the STRELOAD register. 2. Clear the STCURRENT register by writing to it with any value. 3. Configure the STCTRL register for the required operation. Note: When the processor is halted for debugging, the counter does not decrement. June 12, 2014 113 Texas Instruments-Production Data Cortex-M4 Peripherals 3.1.2 Nested Vectored Interrupt Controller (NVIC) This section describes the Nested Vectored Interrupt Controller (NVIC) and the registers it uses. The NVIC supports: ■ 64 interrupts. ■ A programmable priority level of 0-7 for each interrupt. A higher level corresponds to a lower priority, so level 0 is the highest interrupt priority. ■ Low-latency exception and interrupt handling. ■ Level and pulse detection of interrupt signals. ■ Dynamic reprioritization of interrupts. ■ Grouping of priority values into group priority and subpriority fields. ■ Interrupt tail-chaining. ■ An external Non-maskable interrupt (NMI). The processor automatically stacks its state on exception entry and unstacks this state on exception exit, with no instruction overhead, providing low latency exception handling. 3.1.2.1 Level-Sensitive and Pulse Interrupts The processor supports both level-sensitive and pulse interrupts. Pulse interrupts are also described as edge-triggered interrupts. A level-sensitive interrupt is held asserted until the peripheral deasserts the interrupt signal. Typically this happens because the ISR accesses the peripheral, causing it to clear the interrupt request. A pulse interrupt is an interrupt signal sampled synchronously on the rising edge of the processor clock. To ensure the NVIC detects the interrupt, the peripheral must assert the interrupt signal for at least one clock cycle, during which the NVIC detects the pulse and latches the interrupt. When the processor enters the ISR, it automatically removes the pending state from the interrupt (see “Hardware and Software Control of Interrupts” on page 114 for more information). For a level-sensitive interrupt, if the signal is not deasserted before the processor returns from the ISR, the interrupt becomes pending again, and the processor must execute its ISR again. As a result, the peripheral can hold the interrupt signal asserted until it no longer needs servicing. 3.1.2.2 Hardware and Software Control of Interrupts The Cortex-M4 latches all interrupts. A peripheral interrupt becomes pending for one of the following reasons: ■ The NVIC detects that the interrupt signal is High and the interrupt is not active. ■ The NVIC detects a rising edge on the interrupt signal. ■ Software writes to the corresponding interrupt set-pending register bit, or to the Software Trigger Interrupt (SWTRIG) register to make a Software-Generated Interrupt pending. See the INT bit in the PEND0 register on page 136 or SWTRIG on page 146. A pending interrupt remains pending until one of the following: 114 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller ■ The processor enters the ISR for the interrupt, changing the state of the interrupt from pending to active. Then: – For a level-sensitive interrupt, when the processor returns from the ISR, the NVIC samples the interrupt signal. If the signal is asserted, the state of the interrupt changes to pending, which might cause the processor to immediately re-enter the ISR. Otherwise, the state of the interrupt changes to inactive. – For a pulse interrupt, the NVIC continues to monitor the interrupt signal, and if this is pulsed the state of the interrupt changes to pending and active. In this case, when the processor returns from the ISR the state of the interrupt changes to pending, which might cause the processor to immediately re-enter the ISR. If the interrupt signal is not pulsed while the processor is in the ISR, when the processor returns from the ISR the state of the interrupt changes to inactive. ■ Software writes to the corresponding interrupt clear-pending register bit – For a level-sensitive interrupt, if the interrupt signal is still asserted, the state of the interrupt does not change. Otherwise, the state of the interrupt changes to inactive. – For a pulse interrupt, the state of the interrupt changes to inactive, if the state was pending or to active, if the state was active and pending. 3.1.3 System Control Block (SCB) The System Control Block (SCB) provides system implementation information and system control, including configuration, control, and reporting of the system exceptions. 3.1.4 Memory Protection Unit (MPU) This section describes the Memory protection unit (MPU). The MPU divides the memory map into a number of regions and defines the location, size, access permissions, and memory attributes of each region. The MPU supports independent attribute settings for each region, overlapping regions, and export of memory attributes to the system. The memory attributes affect the behavior of memory accesses to the region. The Cortex-M4 MPU defines eight separate memory regions, 0-7, and a background region. When memory regions overlap, a memory access is affected by the attributes of the region with the highest number. For example, the attributes for region 7 take precedence over the attributes of any region that overlaps region 7. The background region has the same memory access attributes as the default memory map, but is accessible from privileged software only. The Cortex-M4 MPU memory map is unified, meaning that instruction accesses and data accesses have the same region settings. If a program accesses a memory location that is prohibited by the MPU, the processor generates a memory management fault, causing a fault exception and possibly causing termination of the process in an OS environment. In an OS environment, the kernel can update the MPU region setting dynamically based on the process to be executed. Typically, an embedded OS uses the MPU for memory protection. Configuration of MPU regions is based on memory types (see “Memory Regions, Types and Attributes” on page 84 for more information). June 12, 2014 115 Texas Instruments-Production Data Cortex-M4 Peripherals Table 3-2 on page 116 shows the possible MPU region attributes. See the section called “MPU Configuration for a Tiva™ C Series Microcontroller” on page 120 for guidelines for programming a microcontroller implementation. Table 3-2. Memory Attributes Summary Memory Type Description Strongly Ordered All accesses to Strongly Ordered memory occur in program order. Device Memory-mapped peripherals Normal Normal memory To avoid unexpected behavior, disable the interrupts before updating the attributes of a region that the interrupt handlers might access. Ensure software uses aligned accesses of the correct size to access MPU registers: ■ Except for the MPU Region Attribute and Size (MPUATTR) register, all MPU registers must be accessed with aligned word accesses. ■ The MPUATTR register can be accessed with byte or aligned halfword or word accesses. The processor does not support unaligned accesses to MPU registers. When setting up the MPU, and if the MPU has previously been programmed, disable unused regions to prevent any previous region settings from affecting the new MPU setup. 3.1.4.1 Updating an MPU Region To update the attributes for an MPU region, the MPU Region Number (MPUNUMBER), MPU Region Base Address (MPUBASE) and MPUATTR registers must be updated. Each register can be programmed separately or with a multiple-word write to program all of these registers. You can use the MPUBASEx and MPUATTRx aliases to program up to four regions simultaneously using an STM instruction. Updating an MPU Region Using Separate Words This example simple code configures one region: ; R1 = region number ; R2 = size/enable ; R3 = attributes ; R4 = address LDR R0,=MPUNUMBER STR R1, [R0, #0x0] STR R4, [R0, #0x4] STRH R2, [R0, #0x8] STRH R3, [R0, #0xA] ; ; ; ; ; 0xE000ED98, MPU region number register Region Number Region Base Address Region Size and Enable Region Attribute Disable a region before writing new region settings to the MPU if you have previously enabled the region being changed. For example: ; R1 = region number ; R2 = size/enable ; R3 = attributes ; R4 = address LDR R0,=MPUNUMBER ; 0xE000ED98, MPU region number register 116 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller STR R1, [R0, #0x0] BIC R2, R2, #1 STRH R2, [R0, #0x8] STR R4, [R0, #0x4] STRH R3, [R0, #0xA] ORR R2, #1 STRH R2, [R0, #0x8] ; ; ; ; ; ; ; Region Number Disable Region Size and Enable Region Base Address Region Attribute Enable Region Size and Enable Software must use memory barrier instructions: ■ Before MPU setup, if there might be outstanding memory transfers, such as buffered writes, that might be affected by the change in MPU settings. ■ After MPU setup, if it includes memory transfers that must use the new MPU settings. However, memory barrier instructions are not required if the MPU setup process starts by entering an exception handler, or is followed by an exception return, because the exception entry and exception return mechanism cause memory barrier behavior. Software does not need any memory barrier instructions during MPU setup, because it accesses the MPU through the Private Peripheral Bus (PPB), which is a Strongly Ordered memory region. For example, if all of the memory access behavior is intended to take effect immediately after the programming sequence, then a DSB instruction and an ISB instruction should be used. A DSB is required after changing MPU settings, such as at the end of context switch. An ISB is required if the code that programs the MPU region or regions is entered using a branch or call. If the programming sequence is entered using a return from exception, or by taking an exception, then an ISB is not required. Updating an MPU Region Using Multi-Word Writes The MPU can be programmed directly using multi-word writes, depending how the information is divided. Consider the following reprogramming: ; R1 = region number ; R2 = address ; R3 = size, attributes in one LDR R0, =MPUNUMBER ; 0xE000ED98, MPU region number register STR R1, [R0, #0x0] ; Region Number STR R2, [R0, #0x4] ; Region Base Address STR R3, [R0, #0x8] ; Region Attribute, Size and Enable An STM instruction can be used to optimize this: ; R1 = region number ; R2 = address ; R3 = size, attributes in one LDR R0, =MPUNUMBER ; 0xE000ED98, MPU region number register STM R0, {R1-R3} ; Region number, address, attribute, size and enable This operation can be done in two words for prepacked information, meaning that the MPU Region Base Address (MPUBASE) register (see page 180) contains the required region number and has the VALID bit set. This method can be used when the data is statically packed, for example in a boot loader: June 12, 2014 117 Texas Instruments-Production Data Cortex-M4 Peripherals ; R1 = address and region number in one ; R2 = size and attributes in one LDR R0, =MPUBASE ; 0xE000ED9C, MPU Region Base register STR R1, [R0, #0x0] ; Region base address and region number combined ; with VALID (bit 4) set STR R2, [R0, #0x4] ; Region Attribute, Size and Enable Subregions Regions of 256 bytes or more are divided into eight equal-sized subregions. Set the corresponding bit in the SRD field of the MPU Region Attribute and Size (MPUATTR) register (see page 182) to disable a subregion. The least-significant bit of the SRD field controls the first subregion, and the most-significant bit controls the last subregion. Disabling a subregion means another region overlapping the disabled range matches instead. If no other enabled region overlaps the disabled subregion, the MPU issues a fault. Regions of 32, 64, and 128 bytes do not support subregions. With regions of these sizes, the SRD field must be configured to 0x00, otherwise the MPU behavior is unpredictable. Example of SRD Use Two regions with the same base address overlap. Region one is 128 KB, and region two is 512 KB. To ensure the attributes from region one apply to the first 128 KB region, configure the SRD field for region two to 0x03 to disable the first two subregions, as Figure 3-1 on page 118 shows. Figure 3-1. SRD Use Example Region 2, with subregions Region 1 Base address of both regions 3.1.4.2 Offset from base address 512KB 448KB 384KB 320KB 256KB 192KB 128KB Disabled subregion 64KB Disabled subregion 0 MPU Access Permission Attributes The access permission bits, TEX, S, C, B, AP, and XN of the MPUATTR register, control access to the corresponding memory region. If an access is made to an area of memory without the required permissions, then the MPU generates a permission fault. Table 3-3 on page 118 shows the encodings for the TEX, C, B, and S access permission bits. All encodings are shown for completeness, however the current implementation of the Cortex-M4 does not support the concept of cacheability or shareability. Refer to the section called “MPU Configuration for a Tiva™ C Series Microcontroller” on page 120 for information on programming the MPU for TM4C1231H6PM implementations. Table 3-3. TEX, S, C, and B Bit Field Encoding TEX S 000b x 000 B Memory Type Shareability Other Attributes 0 0 Strongly Ordered Shareable - a 0 1 Device Shareable - x C a 118 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 3-3. TEX, S, C, and B Bit Field Encoding (continued) TEX S C B Memory Type Shareability 000 0 1 0 Normal Not shareable 000 1 1 0 Normal Shareable 000 0 1 1 Normal Not shareable 000 1 1 1 Normal Shareable Other Attributes Outer and inner write-through. No write allocate. 001 0 0 0 Normal Not shareable 001 1 0 0 Normal Shareable Outer and inner non-cacheable. 001 x a 0 1 Reserved encoding - - a 001 x 1 0 Reserved encoding - - 001 0 1 1 Normal Not shareable 001 1 1 1 Normal Shareable Outer and inner write-back. Write and read allocate. 010 x a 0 0 Device Not shareable Nonshared Device. a a 010 x 0 1 Reserved encoding - - 010 x 1 x Reserved encoding - - 1BB 0 A A Normal Not shareable 1BB 1 A A Normal Shareable Cached memory (BB = outer policy, AA = inner policy). a See Table 3-4 for the encoding of the AA and BB bits. a. The MPU ignores the value of this bit. Table 3-4 on page 119 shows the cache policy for memory attribute encodings with a TEX value in the range of 0x4-0x7. Table 3-4. Cache Policy for Memory Attribute Encoding Encoding, AA or BB Corresponding Cache Policy 00 Non-cacheable 01 Write back, write and read allocate 10 Write through, no write allocate 11 Write back, no write allocate Table 3-5 on page 119 shows the AP encodings in the MPUATTR register that define the access permissions for privileged and unprivileged software. Table 3-5. AP Bit Field Encoding AP Bit Field Privileged Permissions Unprivileged Permissions Description 000 No access No access All accesses generate a permission fault. 001 RW No access Access from privileged software only. 010 RW RO Writes by unprivileged software generate a permission fault. 011 RW RW Full access. 100 Unpredictable Unpredictable Reserved. 101 RO No access Reads by privileged software only. June 12, 2014 119 Texas Instruments-Production Data Cortex-M4 Peripherals Table 3-5. AP Bit Field Encoding (continued) AP Bit Field Privileged Permissions Unprivileged Permissions Description 110 RO RO Read-only, by privileged or unprivileged software. 111 RO RO Read-only, by privileged or unprivileged software. MPU Configuration for a Tiva™ C Series Microcontroller Tiva™ C Series microcontrollers have only a single processor and no caches. As a result, the MPU should be programmed as shown in Table 3-6 on page 120. Table 3-6. Memory Region Attributes for Tiva™ C Series Microcontrollers Memory Region TEX S C B Memory Type and Attributes Flash memory 000b 0 1 0 Normal memory, non-shareable, write-through Internal SRAM 000b 1 1 0 Normal memory, shareable, write-through External SRAM 000b 1 1 1 Normal memory, shareable, write-back, write-allocate Peripherals 000b 1 0 1 Device memory, shareable In current Tiva™ C Series microcontroller implementations, the shareability and cache policy attributes do not affect the system behavior. However, using these settings for the MPU regions can make the application code more portable. The values given are for typical situations. 3.1.4.3 MPU Mismatch When an access violates the MPU permissions, the processor generates a memory management fault (see “Exceptions and Interrupts” on page 82 for more information). The MFAULTSTAT register indicates the cause of the fault. See page 167 for more information. 3.1.5 Floating-Point Unit (FPU) This section describes the Floating-Point Unit (FPU) and the registers it uses. The FPU provides: ■ 32-bit instructions for single-precision (C float) data-processing operations ■ Combined multiply and accumulate instructions for increased precision (Fused MAC) ■ Hardware support for conversion, addition, subtraction, multiplication with optional accumulate, division, and square-root ■ Hardware support for denormals and all IEEE rounding modes ■ 32 dedicated 32-bit single-precision registers, also addressable as 16 double-word registers ■ Decoupled three stage pipeline The Cortex-M4F FPU fully supports single-precision add, subtract, multiply, divide, multiply and accumulate, and square root operations. It also provides conversions between fixed-point and floating-point data formats, and floating-point constant instructions. The FPU provides floating-point computation functionality that is compliant with the ANSI/IEEE Std 754-2008, IEEE Standard for Binary Floating-Point Arithmetic, referred to as the IEEE 754 standard. The FPU's single-precision extension registers can also be accessed as 16 doubleword registers for load, store, and move operations. 120 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 3.1.5.1 FPU Views of the Register Bank The FPU provides an extension register file containing 32 single-precision registers. These can be viewed as: ■ Sixteen 64-bit doubleword registers, D0-D15 ■ Thirty-two 32-bit single-word registers, S0-S31 ■ A combination of registers from the above views Figure 3-2. FPU Register Bank S0 S1 S2 S3 S4 S5 S6 S7 ... S28 S29 S30 S31 D0 D1 D2 D3 ... D14 D15 The mapping between the registers is as follows: ■ S maps to the least significant half of D ■ S maps to the most significant half of D For example, you can access the least significant half of the value in D6 by accessing S12, and the most significant half of the elements by accessing S13. 3.1.5.2 Modes of Operation The FPU provides three modes of operation to accommodate a variety of applications. Full-Compliance mode. In Full-Compliance mode, the FPU processes all operations according to the IEEE 754 standard in hardware. Flush-to-Zero mode. Setting the FZ bit of the Floating-Point Status and Control (FPSC) register enables Flush-to-Zero mode. In this mode, the FPU treats all subnormal input operands of arithmetic CDP operations as zeros in the operation. Exceptions that result from a zero operand are signalled appropriately. VABS, VNEG, and VMOV are not considered arithmetic CDP operations and are not affected by Flush-to-Zero mode. A result that is tiny, as described in the IEEE 754 standard, where the destination precision is smaller in magnitude than the minimum normal value before rounding, is replaced with a zero. The IDC bit in FPSC indicates when an input flush occurs. The UFC bit in FPSC indicates when a result flush occurs. Default NaN mode. Setting the DN bit in the FPSC register enables default NaN mode. In this mode, the result of any arithmetic data processing operation that involves an input NaN, or that generates a NaN result, returns the default NaN. Propagation of the fraction bits is maintained only by VABS, June 12, 2014 121 Texas Instruments-Production Data Cortex-M4 Peripherals VNEG, and VMOV operations. All other CDP operations ignore any information in the fraction bits of an input NaN. 3.1.5.3 Compliance with the IEEE 754 standard When Default NaN (DN) and Flush-to-Zero (FZ) modes are disabled, FPv4 functionality is compliant with the IEEE 754 standard in hardware. No support code is required to achieve this compliance. 3.1.5.4 Complete Implementation of the IEEE 754 standard The Cortex-M4F floating point instruction set does not support all operations defined in the IEEE 754-2008 standard. Unsupported operations include, but are not limited to the following: ■ Remainder ■ Round floating-point number to integer-valued floating-point number ■ Binary-to-decimal conversions ■ Decimal-to-binary conversions ■ Direct comparison of single-precision and double-precision values The Cortex-M4 FPU supports fused MAC operations as described in the IEEE standard. For complete implementation of the IEEE 754-2008 standard, floating-point functionality must be augmented with library functions. 3.1.5.5 IEEE 754 standard implementation choices NaN handling All single-precision values with the maximum exponent field value and a nonzero fraction field are valid NaNs. A most-significant fraction bit of zero indicates a Signaling NaN (SNaN). A one indicates a Quiet NaN (QNaN). Two NaN values are treated as different NaNs if they differ in any bit. The below table shows the default NaN values. Sign Fraction Fraction 0 0xFF bit [22] = 1, bits [21:0] are all zeros Processing of input NaNs for ARM floating-point functionality and libraries is defined as follows: ■ In full-compliance mode, NaNs are handled as described in the ARM Architecture Reference Manual. The hardware processes the NaNs directly for arithmetic CDP instructions. For data transfer operations, NaNs are transferred without raising the Invalid Operation exception. For the non-arithmetic CDP instructions, VABS, VNEG, and VMOV, NaNs are copied, with a change of sign if specified in the instructions, without causing the Invalid Operation exception. ■ In default NaN mode, arithmetic CDP instructions involving NaN operands return the default NaN regardless of the fractions of any NaN operands. SNaNs in an arithmetic CDP operation set the IOC flag, FPSCR[0]. NaN handling by data transfer and non-arithmetic CDP instructions is the same as in full-compliance mode. 122 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 3-7. QNaN and SNaN Handling Instruction Type Default NaN Mode With QNaN Operand With SNaN Operand Off The QNaN or one of the QNaN operands, if there is more than one, is returned according to the rules given in the ARM Architecture Reference Manual. IOC set. The SNaN is quieted and the result NaN is determined by the rules given in the ARM Architecture Reference Manual. On Default NaN returns. IOC set. Default NaN returns. Arithmetic CDP Non-arithmetic CDP Off/On a a NaN passes to destination with sign changed as appropriate. FCMP(Z) - Unordered compare. IOC set. Unordered compare. FCMPE(Z) - IOC set. Unordered compare. IOC set. Unordered compare. Load/store Off/On All NaNs transferred. a. IOC is the Invalid Operation exception flag, FPSCR[0]. Comparisons Comparison results modify the flags in the FPSCR. You can use the MVRS APSR_nzcv instruction (formerly FMSTAT) to transfer the current flags from the FPSCR to the APSR. See the ARM Architecture Reference Manual for mapping of IEEE 754-2008 standard predicates to ARM conditions. The flags used are chosen so that subsequent conditional execution of ARM instructions can test the predicates defined in the IEEE standard. Underflow The Cortex-M4F FPU uses the before rounding form of tininess and the inexact result form of loss of accuracy as described in the IEEE 754-2008 standard to generate Underflow exceptions. In flush-to-zero mode, results that are tiny before rounding, as described in the IEEE standard, are flushed to a zero, and the UFC flag, FPSCR[3], is set. See the ARM Architecture Reference Manual for information on flush-to-zero mode. When the FPU is not in flush-to-zero mode, operations are performed on subnormal operands. If the operation does not produce a tiny result, it returns the computed result, and the UFC flag, FPSCR[3], is not set. The IXC flag, FPSCR[4], is set if the operation is inexact. If the operation produces a tiny result, the result is a subnormal or zero value, and the UFC flag, FPSCR[3], is set if the result was also inexact. 3.1.5.6 Exceptions The FPU sets the cumulative exception status flag in the FPSCR register as required for each instruction, in accordance with the FPv4 architecture. The FPU does not support user-mode traps. The exception enable bits in the FPSCR read-as-zero, and writes are ignored. The processor also has six output pins, FPIXC, FPUFC, FPOFC, FPDZC, FPIDC, and FPIOC, that each reflect the status of one of the cumulative exception flags. For a description of these outputs, see the ARM Cortex-M4 Integration and Implementation Manual (ARM DII 0239, available from ARM). The processor can reduce the exception latency by using lazy stacking. See Auxiliary Control Register, ACTLR on page 4-5. This means that the processor reserves space on the stack for the FP state, but does not save that state information to the stack. See the ARMv7-M Architecture Reference Manual (available from ARM) for more information. 3.1.5.7 Enabling the FPU The FPU is disabled from reset. You must enable it before you can use any floating-point instructions. The processor must be in privileged mode to read from and write to the Coprocessor Access June 12, 2014 123 Texas Instruments-Production Data Cortex-M4 Peripherals Control (CPAC) register. The below example code sequence enables the FPU in both privileged and user modes. ; CPACR is located at address 0xE000ED88 LDR.W R0, =0xE000ED88 ; Read CPACR LDR R1, [R0] ; Set bits 20-23 to enable CP10 and CP11 coprocessors ORR R1, R1, #(0xF 0, then the conversion result > 0x800 (range is 0x800–0xFFF) ■ If VIND < 0, then the conversion result < 0x800 (range is 0–0x800) When using differential sampling, the following definitions are relevant: ■ Input Common Mode Voltage: VINCM = (VIN+ + VIN-) / 2 ■ Reference Positive Voltage: VREFP ■ Reference Negative Voltage: VREFN ■ Reference Differential Voltage: VREFD = VREFP - VREFN ■ Reference Common Mode Voltage: VREFCM = (VREFP + VREFN) / 2 The following conditions provide optimal results in differential mode: ■ Both VIN_EVEN and VIN_ODD must be in the range of (VREFP to VREFN) for a valid conversion result ■ The maximum possible differential input swing, or the maximum differential range, is: -VREFDto +VREFD, so the maximum peak-to-peak input differential signal is (+VREFD - -VREFD) = 2 * VREFD= 2 * (VREFP - VREFN) ■ In order to take advantage of the maximum possible differential input swing, VINCM should be very close to VREFCM, see Table 21-32 on page 1127. If VINCM is not equal to VREFCM, the differential input signal may clip at either maximum or minimum voltage, because either single ended input can never be larger than VREFP or smaller than VREFN, and it is not possible to achieve full swing. Thus any difference in common mode between the input voltage and the reference voltage limits the differential dynamic range of the ADC. Because the maximum peak-to-peak differential signal voltage is 2 * (VREFP - VREFN), the ADC codes are interpreted as: mV per ADC code = (2 *(VREFP - VREFN)) / 4096 Figure 13-10 shows how the differential voltage, ∆V, is represented in ADC codes. 776 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 13-10. Differential Voltage Representation 0xFFF 0x800 -(VREFP - VREFN) 0 VREFP - VREFN V - Input Saturation 13.3.6 Internal Temperature Sensor The temperature sensor serves two primary purposes: 1) to notify the system that internal temperature is too high or low for reliable operation and 2) to provide temperature measurements for calibration of the Hibernate module RTC trim value. The temperature sensor does not have a separate enable, because it also contains the bandgap reference and must always be enabled. The reference is supplied to other analog modules; not just the ADC. In addition, the temperature sensor has a second power-down input in the 3.3 V domain which provides control by the Hibernation module. The internal temperature sensor converts a temperature measurement into a voltage. This voltage value, VTSENS, is given by the following equation (where TEMP is the temperature in °C): VTSENS = 2.7 - ((TEMP + 55) / 75) This relation is shown in Figure 13-11 on page 778. June 12, 2014 777 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Figure 13-11. Internal Temperature Sensor Characteristic VTSENS VTSENS = 2.7 V – (TEMP+55) 75 2.5 V 1.633 V 0.833 V -40° C 25° C 85° C Temp The temperature sensor reading can be sampled in a sample sequence by setting the TSn bit in the ADCSSCTLn register. The temperature reading from the temperature sensor can also be given as a function of the ADC value. The following formula calculates temperature (TEMP in ℃) based on the ADC reading (ADCCODE, given as an unsigned decimal number from 0 to 4095) and the maximum ADC voltage range (VREFP - VREFN): TEMP = 147.5 - ((75 * (VREFP - VREFN) × ADCCODE) / 4096) 13.3.7 Digital Comparator Unit An ADC is commonly used to sample an external signal and to monitor its value to ensure that it remains in a given range. To automate this monitoring procedure and reduce the amount of processor overhead that is required, each module provides eight digital comparators. Conversions from the ADC that are sent to the digital comparators are compared against the user programmable limits in the ADC Digital Comparator Range (ADCDCCMPn) registers. The ADC can be configured to generate an interrupt depending on whether the ADC is operating within the low, mid or high-band region configured in the ADCDCCMPn bit fields. The digital comparators four operational modes (Once, Always, Hysteresis Once, Hysteresis Always) can be additionally applied to the interrupt configuration. 13.3.7.1 Output Functions ADC conversions can either be stored in the ADC Sample Sequence FIFOs or compared using the digital comparator resources as defined by the SnDCOP bits in the ADC Sample Sequence n Operation (ADCSSOPn) register. These selected ADC conversions are used by their respective digital comparator to monitor the external signal. Each comparator has two possible output functions: processor interrupts and triggers. Each function has its own state machine to track the monitored signal. Even though the interrupt and trigger functions can be enabled individually or both at the same time, the same conversion 778 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller data is used by each function to determine if the right conditions have been met to assert the associated output. Interrupts The digital comparator interrupt function is enabled by setting the CIE bit in the ADC Digital Comparator Control (ADCDCCTLn) register. This bit enables the interrupt function state machine to start monitoring the incoming ADC conversions. When the appropriate set of conditions is met, and the DCONSSx bit is set in the ADCIM register, an interrupt is sent to the interrupt controller. Note: 13.3.7.2 Only a single DCONSSn bit should be set at any given time. Setting more than one of these bits results in the INRDC bit from the ADCRIS register being masked, and no interrupt is generated on any of the sample sequencer interrupt lines. It is recommended that when interrupts are used, they are enabled on alternating samples or at the end of the sample sequence. Operational Modes Four operational modes are provided to support a broad range of applications and multiple possible signaling requirements: Always, Once, Hysteresis Always, and Hysteresis Once. The operational mode is selected using the CIM field in the ADCDCCTLn register. Always Mode In the Always operational mode, the associated interrupt or trigger is asserted whenever the ADC conversion value meets its comparison criteria. The result is a string of assertions on the interrupt or trigger while the conversions are within the appropriate range. Once Mode In the Once operational mode, the associated interrupt or trigger is asserted whenever the ADC conversion value meets its comparison criteria, and the previous ADC conversion value did not. The result is a single assertion of the interrupt or trigger when the conversions are within the appropriate range. Hysteresis-Always Mode The Hysteresis-Always operational mode can only be used in conjunction with the low-band or high-band regions because the mid-band region must be crossed and the opposite region entered to clear the hysteresis condition. In the Hysteresis-Always mode, the associated interrupt or trigger is asserted in the following cases: 1) the ADC conversion value meets its comparison criteria or 2) a previous ADC conversion value has met the comparison criteria, and the hysteresis condition has not been cleared by entering the opposite region. The result is a string of assertions on the interrupt or trigger that continue until the opposite region is entered. Hysteresis-Once Mode The Hysteresis-Once operational mode can only be used in conjunction with the low-band or high-band regions because the mid-band region must be crossed and the opposite region entered to clear the hysteresis condition. In the Hysteresis-Once mode, the associated interrupt or trigger is asserted only when the ADC conversion value meets its comparison criteria, the hysteresis condition is clear, and the previous ADC conversion did not meet the comparison criteria. The result is a single assertion on the interrupt or trigger. June 12, 2014 779 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) 13.3.7.3 Function Ranges The two comparison values, COMP0 and COMP1, in the ADC Digital Comparator Range (ADCDCCMPn) register effectively break the conversion area into three distinct regions. These regions are referred to as the low-band (less than COMP0), mid-band (greater than COMP0 but less than or equal to COMP1), and high-band (greater than or equal to COMP1) regions. COMP0 and COMP1 may be programmed to the same value, effectively creating two regions, but COMP1 must always be greater than or equal to the value of COMP0. A COMP1 value that is less than COMP0 generates unpredictable results. Low-Band Operation To operate in the low-band region, the CIC field field in the ADCDCCTLn register must be programmed to 0x0. This setting causes interrupts or triggers to be generated in the low-band region as defined by the programmed operational mode. An example of the state of the interrupt/trigger signal in the low-band region for each of the operational modes is shown in Figure 13-12 on page 780. Note that a "0" in a column following the operational mode name (Always, Once, Hysteresis Always, and Hysteresis Once) indicates that the interrupt or trigger signal is deasserted and a "1" indicates that the signal is asserted. Figure 13-12. Low-Band Operation (CIC=0x0) COMP1 COMP0 Always – 0 0 0 0 1 1 1 0 0 1 1 0 0 0 0 1 Once – 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 1 Hysteresis Always – 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 1 Hysteresis Once – 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 Mid-Band Operation To operate in the mid-band region, the CIC field field in the ADCDCCTLn register must be programmed to 0x1. This setting causes interrupts or triggers to be generated in the mid-band region according the operation mode. Only the Always and Once operational modes are available in the mid-band region. An example of the state of the interrupt/trigger signal in the mid-band region for each of the allowed operational modes is shown in Figure 13-13 on page 781. Note that a "0" in a column following the operational mode name (Always or Once) indicates that the interrupt or trigger signal is deasserted and a "1" indicates that the signal is asserted. 780 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 13-13. Mid-Band Operation (CIC=0x1) COMP1 COMP0 Always – 0 0 1 1 0 0 0 1 1 1 0 0 1 1 0 0 Once – 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 Hysteresis Always – - - - - - - - - - - - - - - - - Hysteresis Once – - - - - - - - - - - - - - - - - High-Band Operation To operate in the high-band region, the CIC field field in the ADCDCCTLn register must be programmed to 0x3. This setting causes interrupts or triggers to be generated in the high-band region according the operation mode. An example of the state of the interrupt/trigger signal in the high-band region for each of the allowed operational modes is shown in Figure 13-14 on page 782. Note that a "0" in a column following the operational mode name (Always, Once, Hysteresis Always, and Hysteresis Once) indicates that the interrupt or trigger signal is deasserted and a "1" indicates that the signal is asserted. June 12, 2014 781 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Figure 13-14. High-Band Operation (CIC=0x3) COMP1 COMP0 13.4 Always – 0 0 0 0 1 1 1 0 0 1 1 0 0 0 1 1 Once – 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 Hysteresis Always – 0 0 0 0 1 1 1 1 1 1 1 1 0 0 1 1 Hysteresis Once – 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 Initialization and Configuration In order for the ADC module to be used, the PLL must be enabled and programmed to a supported crystal frequency in the RCC register (see page 241). Using unsupported frequencies can cause faulty operation in the ADC module. 13.4.1 Module Initialization Initialization of the ADC module is a simple process with very few steps: enabling the clock to the ADC, disabling the analog isolation circuit associated with all inputs that are to be used, and reconfiguring the sample sequencer priorities (if needed). The initialization sequence for the ADC is as follows: 1. Enable the ADC clock using the RCGCADC register (see page 332). 2. Enable the clock to the appropriate GPIO modules via the RCGCGPIO register (see page 321). To find out which GPIO ports to enable, refer to “Signal Description” on page 766. 3. Set the GPIO AFSEL bits for the ADC input pins (see page 636). To determine which GPIOs to configure, see Table 20-4 on page 1087. 4. Configure the AINx signals to be analog inputs by clearing the corresponding DEN bit in the GPIO Digital Enable (GPIODEN) register (see page 647). 5. Disable the analog isolation circuit for all ADC input pins that are to be used by writing a 1 to the appropriate bits of the GPIOAMSEL register (see page 652) in the associated GPIO block. 782 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 6. If required by the application, reconfigure the sample sequencer priorities in the ADCSSPRI register. The default configuration has Sample Sequencer 0 with the highest priority and Sample Sequencer 3 as the lowest priority. 13.4.2 Sample Sequencer Configuration Configuration of the sample sequencers is slightly more complex than the module initialization because each sample sequencer is completely programmable. The configuration for each sample sequencer should be as follows: 1. Ensure that the sample sequencer is disabled by clearing the corresponding ASENn bit in the ADCACTSS register. Programming of the sample sequencers is allowed without having them enabled. Disabling the sequencer during programming prevents erroneous execution if a trigger event were to occur during the configuration process. 2. Configure the trigger event for the sample sequencer in the ADCEMUX register. 3. For each sample in the sample sequence, configure the corresponding input source in the ADCSSMUXn register. 4. For each sample in the sample sequence, configure the sample control bits in the corresponding nibble in the ADCSSCTLn register. When programming the last nibble, ensure that the END bit is set. Failure to set the END bit causes unpredictable behavior. 5. If interrupts are to be used, set the corresponding MASK bit in the ADCIM register. 6. Enable the sample sequencer logic by setting the corresponding ASENn bit in the ADCACTSS register. 13.5 Register Map Table 13-4 on page 783 lists the ADC registers. The offset listed is a hexadecimal increment to the register's address, relative to that ADC module's base address of: ■ ADC0: 0x4003.8000 ■ ADC1: 0x4003.9000 Note that the ADC module clock must be enabled before the registers can be programmed (see page 332). There must be a delay of 3 system clocks after the ADC module clock is enabled before any ADC module registers are accessed. Table 13-4. ADC Register Map Offset Name 0x000 Description See page Type Reset ADCACTSS RW 0x0000.0000 ADC Active Sample Sequencer 786 0x004 ADCRIS RO 0x0000.0000 ADC Raw Interrupt Status 788 0x008 ADCIM RW 0x0000.0000 ADC Interrupt Mask 790 0x00C ADCISC RW1C 0x0000.0000 ADC Interrupt Status and Clear 793 0x010 ADCOSTAT RW1C 0x0000.0000 ADC Overflow Status 796 0x014 ADCEMUX RW 0x0000.0000 ADC Event Multiplexer Select 798 June 12, 2014 783 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Table 13-4. ADC Register Map (continued) Offset Name 0x018 See page Type Reset Description ADCUSTAT RW1C 0x0000.0000 ADC Underflow Status 803 0x020 ADCSSPRI RW 0x0000.3210 ADC Sample Sequencer Priority 804 0x024 ADCSPC RW 0x0000.0000 ADC Sample Phase Control 806 0x028 ADCPSSI RW - ADC Processor Sample Sequence Initiate 808 0x030 ADCSAC RW 0x0000.0000 ADC Sample Averaging Control 810 0x034 ADCDCISC RW1C 0x0000.0000 ADC Digital Comparator Interrupt Status and Clear 811 0x038 ADCCTL RW 0x0000.0000 ADC Control 813 0x040 ADCSSMUX0 RW 0x0000.0000 ADC Sample Sequence Input Multiplexer Select 0 814 0x044 ADCSSCTL0 RW 0x0000.0000 ADC Sample Sequence Control 0 816 0x048 ADCSSFIFO0 RO - ADC Sample Sequence Result FIFO 0 823 0x04C ADCSSFSTAT0 RO 0x0000.0100 ADC Sample Sequence FIFO 0 Status 824 0x050 ADCSSOP0 RW 0x0000.0000 ADC Sample Sequence 0 Operation 826 0x054 ADCSSDC0 RW 0x0000.0000 ADC Sample Sequence 0 Digital Comparator Select 828 0x060 ADCSSMUX1 RW 0x0000.0000 ADC Sample Sequence Input Multiplexer Select 1 830 0x064 ADCSSCTL1 RW 0x0000.0000 ADC Sample Sequence Control 1 831 0x068 ADCSSFIFO1 RO - ADC Sample Sequence Result FIFO 1 823 0x06C ADCSSFSTAT1 RO 0x0000.0100 ADC Sample Sequence FIFO 1 Status 824 0x070 ADCSSOP1 RW 0x0000.0000 ADC Sample Sequence 1 Operation 835 0x074 ADCSSDC1 RW 0x0000.0000 ADC Sample Sequence 1 Digital Comparator Select 836 0x080 ADCSSMUX2 RW 0x0000.0000 ADC Sample Sequence Input Multiplexer Select 2 830 0x084 ADCSSCTL2 RW 0x0000.0000 ADC Sample Sequence Control 2 831 0x088 ADCSSFIFO2 RO - ADC Sample Sequence Result FIFO 2 823 0x08C ADCSSFSTAT2 RO 0x0000.0100 ADC Sample Sequence FIFO 2 Status 824 0x090 ADCSSOP2 RW 0x0000.0000 ADC Sample Sequence 2 Operation 835 0x094 ADCSSDC2 RW 0x0000.0000 ADC Sample Sequence 2 Digital Comparator Select 836 0x0A0 ADCSSMUX3 RW 0x0000.0000 ADC Sample Sequence Input Multiplexer Select 3 838 0x0A4 ADCSSCTL3 RW 0x0000.0000 ADC Sample Sequence Control 3 839 0x0A8 ADCSSFIFO3 RO - ADC Sample Sequence Result FIFO 3 823 0x0AC ADCSSFSTAT3 RO 0x0000.0100 ADC Sample Sequence FIFO 3 Status 824 0x0B0 ADCSSOP3 RW 0x0000.0000 ADC Sample Sequence 3 Operation 841 0x0B4 ADCSSDC3 RW 0x0000.0000 ADC Sample Sequence 3 Digital Comparator Select 842 0xD00 ADCDCRIC WO 0x0000.0000 ADC Digital Comparator Reset Initial Conditions 843 784 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 13-4. ADC Register Map (continued) Offset Name 0xE00 Reset ADCDCCTL0 RW 0x0000.0000 ADC Digital Comparator Control 0 848 0xE04 ADCDCCTL1 RW 0x0000.0000 ADC Digital Comparator Control 1 848 0xE08 ADCDCCTL2 RW 0x0000.0000 ADC Digital Comparator Control 2 848 0xE0C ADCDCCTL3 RW 0x0000.0000 ADC Digital Comparator Control 3 848 0xE10 ADCDCCTL4 RW 0x0000.0000 ADC Digital Comparator Control 4 848 0xE14 ADCDCCTL5 RW 0x0000.0000 ADC Digital Comparator Control 5 848 0xE18 ADCDCCTL6 RW 0x0000.0000 ADC Digital Comparator Control 6 848 0xE1C ADCDCCTL7 RW 0x0000.0000 ADC Digital Comparator Control 7 848 0xE40 ADCDCCMP0 RW 0x0000.0000 ADC Digital Comparator Range 0 850 0xE44 ADCDCCMP1 RW 0x0000.0000 ADC Digital Comparator Range 1 850 0xE48 ADCDCCMP2 RW 0x0000.0000 ADC Digital Comparator Range 2 850 0xE4C ADCDCCMP3 RW 0x0000.0000 ADC Digital Comparator Range 3 850 0xE50 ADCDCCMP4 RW 0x0000.0000 ADC Digital Comparator Range 4 850 0xE54 ADCDCCMP5 RW 0x0000.0000 ADC Digital Comparator Range 5 850 0xE58 ADCDCCMP6 RW 0x0000.0000 ADC Digital Comparator Range 6 850 0xE5C ADCDCCMP7 RW 0x0000.0000 ADC Digital Comparator Range 7 850 0xFC0 ADCPP RO 0x00B0.20C7 ADC Peripheral Properties 851 0xFC4 ADCPC RW 0x0000.0007 ADC Peripheral Configuration 853 0xFC8 ADCCC RW 0x0000.0000 ADC Clock Configuration 854 13.6 Description See page Type Register Descriptions The remainder of this section lists and describes the ADC registers, in numerical order by address offset. June 12, 2014 785 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 1: ADC Active Sample Sequencer (ADCACTSS), offset 0x000 This register controls the activation of the sample sequencers. Each sample sequencer can be enabled or disabled independently. ADC Active Sample Sequencer (ADCACTSS) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x000 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 24 23 22 21 20 19 18 17 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 9 8 7 6 5 4 3 2 1 0 ASEN3 ASEN2 ASEN1 ASEN0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset BUSY reserved Type Reset 16 Bit/Field Name Type Reset Description 31:17 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 16 BUSY RO 0 ADC Busy Value Description 0 ADC is idle 1 ADC is busy 15:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 ASEN3 RW 0 ADC SS3 Enable Value Description 2 ASEN2 RW 0 0 Sample Sequencer 3 is disabled. 1 Sample Sequencer 3 is enabled. ADC SS2 Enable Value Description 1 ASEN1 RW 0 0 Sample Sequencer 2 is disabled. 1 Sample Sequencer 2 is enabled. ADC SS1 Enable Value Description 0 Sample Sequencer 1 is disabled. 1 Sample Sequencer 1 is enabled. 786 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 0 ASEN0 RW 0 Description ADC SS0 Enable Value Description 0 Sample Sequencer 0 is disabled. 1 Sample Sequencer 0 is enabled. June 12, 2014 787 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 2: ADC Raw Interrupt Status (ADCRIS), offset 0x004 This register shows the status of the raw interrupt signal of each sample sequencer. These bits may be polled by software to look for interrupt conditions without sending the interrupts to the interrupt controller. ADC Raw Interrupt Status (ADCRIS) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x004 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 24 23 22 21 20 19 18 17 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 9 8 7 6 5 4 3 2 1 0 INR3 INR2 INR1 INR0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset INRDC reserved Type Reset 16 Bit/Field Name Type Reset Description 31:17 reserved RO 0x000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 16 INRDC RO 0 Digital Comparator Raw Interrupt Status Value Description 0 All bits in the ADCDCISC register are clear. 1 At least one bit in the ADCDCISC register is set, meaning that a digital comparator interrupt has occurred. 15:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 INR3 RO 0 SS3 Raw Interrupt Status Value Description 0 An interrupt has not occurred. 1 A sample has completed conversion and the respective ADCSSCTL3 IEn bit is set, enabling a raw interrupt. This bit is cleared by writing a 1 to the IN3 bit in the ADCISC register. 2 INR2 RO 0 SS2 Raw Interrupt Status Value Description 0 An interrupt has not occurred. 1 A sample has completed conversion and the respective ADCSSCTL2 IEn bit is set, enabling a raw interrupt. This bit is cleared by writing a 1 to the IN2 bit in the ADCISC register. 788 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 1 INR1 RO 0 Description SS1 Raw Interrupt Status Value Description 0 An interrupt has not occurred. 1 A sample has completed conversion and the respective ADCSSCTL1 IEn bit is set, enabling a raw interrupt. This bit is cleared by writing a 1 to the IN1 bit in the ADCISC register. 0 INR0 RO 0 SS0 Raw Interrupt Status Value Description 0 An interrupt has not occurred. 1 A sample has completed conversion and the respective ADCSSCTL0 IEn bit is set, enabling a raw interrupt. This bit is cleared by writing a 1 to the IN0 bit in the ADCISC register. June 12, 2014 789 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 3: ADC Interrupt Mask (ADCIM), offset 0x008 This register controls whether the sample sequencer and digital comparator raw interrupt signals are sent to the interrupt controller. Each raw interrupt signal can be masked independently. Note: Only a single DCONSSn bit should be set at any given time. Setting more than one of these bits results in the INRDC bit from the ADCRIS register being masked, and no interrupt is generated on any of the sample sequencer interrupt lines. It is recommended that when interrupts are used, they are enabled on alternating samples or at the end of the sample sequence. ADC Interrupt Mask (ADCIM) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x008 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 19 18 17 16 DCONSS3 DCONSS2 DCONSS1 DCONSS0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 3 2 1 0 MASK3 MASK2 MASK1 MASK0 RW 0 RW 0 RW 0 RW 0 Bit/Field Name Type Reset Description 31:20 reserved RO 0x000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 19 DCONSS3 RW 0 Digital Comparator Interrupt on SS3 Value Description 18 DCONSS2 RW 0 0 The status of the digital comparators does not affect the SS3 interrupt status. 1 The raw interrupt signal from the digital comparators (INRDC bit in the ADCRIS register) is sent to the interrupt controller on the SS3 interrupt line. Digital Comparator Interrupt on SS2 Value Description 0 The status of the digital comparators does not affect the SS2 interrupt status. 1 The raw interrupt signal from the digital comparators (INRDC bit in the ADCRIS register) is sent to the interrupt controller on the SS2 interrupt line. 790 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 17 DCONSS1 RW 0 Description Digital Comparator Interrupt on SS1 Value Description 16 DCONSS0 RW 0 0 The status of the digital comparators does not affect the SS1 interrupt status. 1 The raw interrupt signal from the digital comparators (INRDC bit in the ADCRIS register) is sent to the interrupt controller on the SS1 interrupt line. Digital Comparator Interrupt on SS0 Value Description 0 The status of the digital comparators does not affect the SS0 interrupt status. 1 The raw interrupt signal from the digital comparators (INRDC bit in the ADCRIS register) is sent to the interrupt controller on the SS0 interrupt line. 15:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 MASK3 RW 0 SS3 Interrupt Mask Value Description 2 MASK2 RW 0 0 The status of Sample Sequencer 3 does not affect the SS3 interrupt status. 1 The raw interrupt signal from Sample Sequencer 3 (ADCRIS register INR3 bit) is sent to the interrupt controller. SS2 Interrupt Mask Value Description 1 MASK1 RW 0 0 The status of Sample Sequencer 2 does not affect the SS2 interrupt status. 1 The raw interrupt signal from Sample Sequencer 2 (ADCRIS register INR2 bit) is sent to the interrupt controller. SS1 Interrupt Mask Value Description 0 The status of Sample Sequencer 1 does not affect the SS1 interrupt status. 1 The raw interrupt signal from Sample Sequencer 1 (ADCRIS register INR1 bit) is sent to the interrupt controller. June 12, 2014 791 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 0 MASK0 RW 0 Description SS0 Interrupt Mask Value Description 0 The status of Sample Sequencer 0 does not affect the SS0 interrupt status. 1 The raw interrupt signal from Sample Sequencer 0 (ADCRIS register INR0 bit) is sent to the interrupt controller. 792 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 4: ADC Interrupt Status and Clear (ADCISC), offset 0x00C This register provides the mechanism for clearing sample sequencer interrupt conditions and shows the status of interrupts generated by the sample sequencers and the digital comparators which have been sent to the interrupt controller. When read, each bit field is the logical AND of the respective INR and MASK bits. Sample sequencer interrupts are cleared by writing a 1 to the corresponding bit position. Digital comparator interrupts are cleared by writing a 1 to the appropriate bits in the ADCDCISC register. If software is polling the ADCRIS instead of generating interrupts, the sample sequence INRn bits are still cleared via the ADCISC register, even if the INn bit is not set. ADC Interrupt Status and Clear (ADCISC) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x00C Type RW1C, reset 0x0000.0000 31 30 29 28 27 26 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 25 24 23 22 21 20 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 9 8 7 6 5 4 3 2 1 0 IN3 IN2 IN1 IN0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW1C 0 RW1C 0 RW1C 0 RW1C 0 reserved Type Reset 18 17 16 DCINSS3 DCINSS2 DCINSS1 DCINSS0 reserved Type Reset 19 Bit/Field Name Type Reset Description 31:20 reserved RO 0x000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 19 DCINSS3 RO 0 Digital Comparator Interrupt Status on SS3 Value Description 0 No interrupt has occurred or the interrupt is masked. 1 Both the INRDC bit in the ADCRIS register and the DCONSS3 bit in the ADCIM register are set, providing a level-based interrupt to the interrupt controller. This bit is cleared by writing a 1 to it. Clearing this bit also clears the INRDC bit in the ADCRIS register. 18 DCINSS2 RO 0 Digital Comparator Interrupt Status on SS2 Value Description 0 No interrupt has occurred or the interrupt is masked. 1 Both the INRDC bit in the ADCRIS register and the DCONSS2 bit in the ADCIM register are set, providing a level-based interrupt to the interrupt controller. This bit is cleared by writing a 1 to it. Clearing this bit also clears the INRDC bit in the ADCRIS register. June 12, 2014 793 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 17 DCINSS1 RO 0 Description Digital Comparator Interrupt Status on SS1 Value Description 0 No interrupt has occurred or the interrupt is masked. 1 Both the INRDC bit in the ADCRIS register and the DCONSS1 bit in the ADCIM register are set, providing a level-based interrupt to the interrupt controller. This bit is cleared by writing a 1 to it. Clearing this bit also clears the INRDC bit in the ADCRIS register. 16 DCINSS0 RO 0 Digital Comparator Interrupt Status on SS0 Value Description 0 No interrupt has occurred or the interrupt is masked. 1 Both the INRDC bit in the ADCRIS register and the DCONSS0 bit in the ADCIM register are set, providing a level-based interrupt to the interrupt controller. This bit is cleared by writing a 1 to it. Clearing this bit also clears the INRDC bit in the ADCRIS register. 15:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 IN3 RW1C 0 SS3 Interrupt Status and Clear Value Description 0 No interrupt has occurred or the interrupt is masked. 1 Both the INR3 bit in the ADCRIS register and the MASK3 bit in the ADCIM register are set, providing a level-based interrupt to the interrupt controller. This bit is cleared by writing a 1. Clearing this bit also clears the INR3 bit in the ADCRIS register. 2 IN2 RW1C 0 SS2 Interrupt Status and Clear Value Description 0 No interrupt has occurred or the interrupt is masked. 1 Both the INR2 bit in the ADCRIS register and the MASK2 bit in the ADCIM register are set, providing a level-based interrupt to the interrupt controller. This bit is cleared by writing a 1. Clearing this bit also clears the INR2 bit in the ADCRIS register. 794 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 1 IN1 RW1C 0 Description SS1 Interrupt Status and Clear Value Description 0 No interrupt has occurred or the interrupt is masked. 1 Both the INR1 bit in the ADCRIS register and the MASK1 bit in the ADCIM register are set, providing a level-based interrupt to the interrupt controller. This bit is cleared by writing a 1. Clearing this bit also clears the INR1 bit in the ADCRIS register. 0 IN0 RW1C 0 SS0 Interrupt Status and Clear Value Description 0 No interrupt has occurred or the interrupt is masked. 1 Both the INR0 bit in the ADCRIS register and the MASK0 bit in the ADCIM register are set, providing a level-based interrupt to the interrupt controller. This bit is cleared by writing a 1. Clearing this bit also clears the INR0 bit in the ADCRIS register. June 12, 2014 795 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 5: ADC Overflow Status (ADCOSTAT), offset 0x010 This register indicates overflow conditions in the sample sequencer FIFOs. Once the overflow condition has been handled by software, the condition can be cleared by writing a 1 to the corresponding bit position. ADC Overflow Status (ADCOSTAT) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x010 Type RW1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 OV3 OV2 OV1 OV0 RO 0 RO 0 RO 0 RO 0 RO 0 RW1C 0 RW1C 0 RW1C 0 RW1C 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3 OV3 RW1C 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SS3 FIFO Overflow Value Description 0 The FIFO has not overflowed. 1 The FIFO for Sample Sequencer 3 has hit an overflow condition, meaning that the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped. This bit is cleared by writing a 1. 2 OV2 RW1C 0 SS2 FIFO Overflow Value Description 0 The FIFO has not overflowed. 1 The FIFO for Sample Sequencer 2 has hit an overflow condition, meaning that the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped. This bit is cleared by writing a 1. 1 OV1 RW1C 0 SS1 FIFO Overflow Value Description 0 The FIFO has not overflowed. 1 The FIFO for Sample Sequencer 1 has hit an overflow condition, meaning that the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped. This bit is cleared by writing a 1. 796 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 0 OV0 RW1C 0 Description SS0 FIFO Overflow Value Description 0 The FIFO has not overflowed. 1 The FIFO for Sample Sequencer 0 has hit an overflow condition, meaning that the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped. This bit is cleared by writing a 1. June 12, 2014 797 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 6: ADC Event Multiplexer Select (ADCEMUX), offset 0x014 The ADCEMUX selects the event (trigger) that initiates sampling for each sample sequencer. Each sample sequencer can be configured with a unique trigger source. ADC Event Multiplexer Select (ADCEMUX) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x014 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset EM3 Type Reset EM2 EM1 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 EM0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 798 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 15:12 EM3 RW 0x0 Description SS3 Trigger Select This field selects the trigger source for Sample Sequencer 3. The valid configurations for this field are: Value Event 0x0 Processor (default) The trigger is initiated by setting the SSn bit in the ADCPSSI register. 0x1 Analog Comparator 0 This trigger is configured by the Analog Comparator Control 0 (ACCTL0) register (page 1072). 0x2 Analog Comparator 1 This trigger is configured by the Analog Comparator Control 1 (ACCTL1) register (page 1072). 0x3 reserved 0x4 External (GPIO Pins) This trigger is connected to the GPIO interrupt for the corresponding GPIO (see “ADC Trigger Source” on page 620). Note: 0x5 GPIOs that have AINx signals as alternate functions can be used to trigger the ADC. However, the pin cannot be used as both a GPIO and an analog input. Timer In addition, the trigger must be enabled with the TnOTE bit in the GPTMCTL register (page 702). 0x6 reserved 0x7 reserved 0x8 reserved 0x9 reserved 0xA-0xE reserved 0xF Always (continuously sample) June 12, 2014 799 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 11:8 EM2 RW 0x0 Description SS2 Trigger Select This field selects the trigger source for Sample Sequencer 2. The valid configurations for this field are: Value Event 0x0 Processor (default) The trigger is initiated by setting the SSn bit in the ADCPSSI register. 0x1 Analog Comparator 0 This trigger is configured by the Analog Comparator Control 0 (ACCTL0) register (page 1072). 0x2 Analog Comparator 1 This trigger is configured by the Analog Comparator Control 1 (ACCTL1) register (page 1072). 0x3 reserved 0x4 External (GPIO Pins) This trigger is connected to the GPIO interrupt for the corresponding GPIO (see “ADC Trigger Source” on page 620). Note: 0x5 GPIOs that have AINx signals as alternate functions can be used to trigger the ADC. However, the pin cannot be used as both a GPIO and an analog input. Timer In addition, the trigger must be enabled with the TnOTE bit in the GPTMCTL register (page 702). 0x6 reserved 0x7 reserved 0x8 reserved 0x9 reserved 0xA-0xE reserved 0xF Always (continuously sample) 800 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 7:4 EM1 RW 0x0 Description SS1 Trigger Select This field selects the trigger source for Sample Sequencer 1. The valid configurations for this field are: Value Event 0x0 Processor (default) The trigger is initiated by setting the SSn bit in the ADCPSSI register. 0x1 Analog Comparator 0 This trigger is configured by the Analog Comparator Control 0 (ACCTL0) register (page 1072). 0x2 Analog Comparator 1 This trigger is configured by the Analog Comparator Control 1 (ACCTL1) register (page 1072). 0x3 reserved 0x4 External (GPIO Pins) This trigger is connected to the GPIO interrupt for the corresponding GPIO (see “ADC Trigger Source” on page 620). Note: 0x5 GPIOs that have AINx signals as alternate functions can be used to trigger the ADC. However, the pin cannot be used as both a GPIO and an analog input. Timer In addition, the trigger must be enabled with the TnOTE bit in the GPTMCTL register (page 702). 0x6 reserved 0x7 reserved 0x8 reserved 0x9 reserved 0xA-0xE reserved 0xF Always (continuously sample) June 12, 2014 801 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 3:0 EM0 RW 0x0 Description SS0 Trigger Select This field selects the trigger source for Sample Sequencer 0 The valid configurations for this field are: Value Event 0x0 Processor (default) The trigger is initiated by setting the SSn bit in the ADCPSSI register. 0x1 Analog Comparator 0 This trigger is configured by the Analog Comparator Control 0 (ACCTL0) register (page 1072). 0x2 Analog Comparator 1 This trigger is configured by the Analog Comparator Control 1 (ACCTL1) register (page 1072). 0x3 reserved 0x4 External (GPIO Pins) This trigger is connected to the GPIO interrupt for the corresponding GPIO (see “ADC Trigger Source” on page 620). Note: 0x5 GPIOs that have AINx signals as alternate functions can be used to trigger the ADC. However, the pin cannot be used as both a GPIO and an analog input. Timer In addition, the trigger must be enabled with the TnOTE bit in the GPTMCTL register (page 702). 0x6 reserved 0x7 reserved 0x8 reserved 0x9 reserved 0xA-0xE reserved 0xF Always (continuously sample) 802 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 7: ADC Underflow Status (ADCUSTAT), offset 0x018 This register indicates underflow conditions in the sample sequencer FIFOs. The corresponding underflow condition is cleared by writing a 1 to the relevant bit position. ADC Underflow Status (ADCUSTAT) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x018 Type RW1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 UV3 UV2 UV1 UV0 RO 0 RO 0 RO 0 RO 0 RO 0 RW1C 0 RW1C 0 RW1C 0 RW1C 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3 UV3 RW1C 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SS3 FIFO Underflow The valid configurations for this field are shown below. This bit is cleared by writing a 1. Value Description 2 UV2 RW1C 0 0 The FIFO has not underflowed. 1 The FIFO for the Sample Sequencer has hit an underflow condition, meaning that the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. SS2 FIFO Underflow The valid configurations are the same as those for the UV3 field. This bit is cleared by writing a 1. 1 UV1 RW1C 0 SS1 FIFO Underflow The valid configurations are the same as those for the UV3 field. This bit is cleared by writing a 1. 0 UV0 RW1C 0 SS0 FIFO Underflow The valid configurations are the same as those for the UV3 field. This bit is cleared by writing a 1. June 12, 2014 803 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 8: ADC Sample Sequencer Priority (ADCSSPRI), offset 0x020 This register sets the priority for each of the sample sequencers. Out of reset, Sequencer 0 has the highest priority, and Sequencer 3 has the lowest priority. When reconfiguring sequence priorities, each sequence must have a unique priority for the ADC to operate properly. ADC Sample Sequencer Priority (ADCSSPRI) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x020 Type RW, reset 0x0000.3210 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RW 1 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RW 0 RO 0 RO 0 RW 0 RW 1 RO 0 RO 0 RW 0 reserved Type Reset reserved Type Reset RO 0 RO 0 SS3 RW 1 reserved RO 0 SS2 RW 1 Bit/Field Name Type Reset 31:14 reserved RO 0x0000.0 13:12 SS3 RW 0x3 reserved SS1 reserved SS0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SS3 Priority This field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 3. A priority encoding of 0x0 is highest and 0x3 is lowest. The priorities assigned to the sequencers must be uniquely mapped. The ADC may not operate properly if two or more fields are equal. 11:10 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9:8 SS2 RW 0x2 SS2 Priority This field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 2. A priority encoding of 0x0 is highest and 0x3 is lowest. The priorities assigned to the sequencers must be uniquely mapped. The ADC may not operate properly if two or more fields are equal. 7:6 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5:4 SS1 RW 0x1 SS1 Priority This field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 1. A priority encoding of 0x0 is highest and 0x3 is lowest. The priorities assigned to the sequencers must be uniquely mapped. The ADC may not operate properly if two or more fields are equal. 3:2 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 804 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset Description 1:0 SS0 RW 0x0 SS0 Priority This field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 0. A priority encoding of 0x0 is highest and 0x3 is lowest. The priorities assigned to the sequencers must be uniquely mapped. The ADC may not operate properly if two or more fields are equal. June 12, 2014 805 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 9: ADC Sample Phase Control (ADCSPC), offset 0x024 This register allows the ADC module to sample at one of 16 different discrete phases from 0.0° through 337.5°. For example, the sample rate could be effectively doubled by sampling a signal using one ADC module configured with the standard sample time and the second ADC module configured with a 180.0° phase lag. Note: Care should be taken when the PHASE field is non-zero, as the resulting delay in sampling the AINx input may result in undesirable system consequences. The time from ADC trigger to sample is increased and could make the response time longer than anticipated. The added latency could have ramifications in the system design. Designers should carefully consider the impact of this delay. ADC Sample Phase Control (ADCSPC) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x024 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 1 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 PHASE RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 806 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 3:0 PHASE RW 0x0 Description Phase Difference This field selects the sample phase difference from the standard sample time. Value Description 0x0 ADC sample lags by 0.0° 0x1 ADC sample lags by 22.5° 0x2 ADC sample lags by 45.0° 0x3 ADC sample lags by 67.5° 0x4 ADC sample lags by 90.0° 0x5 ADC sample lags by 112.5° 0x6 ADC sample lags by 135.0° 0x7 ADC sample lags by 157.5° 0x8 ADC sample lags by 180.0° 0x9 ADC sample lags by 202.5° 0xA ADC sample lags by 225.0° 0xB ADC sample lags by 247.5° 0xC ADC sample lags by 270.0° 0xD ADC sample lags by 292.5° 0xE ADC sample lags by 315.0° 0xF ADC sample lags by 337.5° June 12, 2014 807 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 10: ADC Processor Sample Sequence Initiate (ADCPSSI), offset 0x028 This register provides a mechanism for application software to initiate sampling in the sample sequencers. Sample sequences can be initiated individually or in any combination. When multiple sequences are triggered simultaneously, the priority encodings in ADCSSPRI dictate execution order. This register also provides a means to configure and then initiate concurrent sampling on all ADC modules. To do this, the first ADC module should be configured. The ADCPSSI register for that module should then be written. The appropriate SS bits should be set along with the SYNCWAIT bit. Additional ADC modules should then be configured following the same procedure. Once the final ADC module is configured, its ADCPSSI register should be written with the appropriate SS bits set along with the GSYNC bit. All of the ADC modules then begin concurrent sampling according to their configuration. ADC Processor Sample Sequence Initiate (ADCPSSI) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x028 Type RW, reset 31 30 GSYNC Type Reset 29 28 reserved 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 reserved SYNCWAIT RW 0 RO 0 RO 0 RO 0 RW 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31 GSYNC RW 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 1 0 SS3 SS2 SS1 SS0 WO - WO - WO - WO - Description Global Synchronize Value Description 30:28 reserved RO 0x0 27 SYNCWAIT RW 0 0 This bit is cleared once sampling has been initiated. 1 This bit initiates sampling in multiple ADC modules at the same time. Any ADC module that has been initialized by setting an SSn bit and the SYNCWAIT bit starts sampling once this bit is written. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Synchronize Wait Value Description 26:4 reserved RO 0x0000.0 0 Sampling begins when a sample sequence has been initiated. 1 This bit allows the sample sequences to be initiated, but delays sampling until the GSYNC bit is set. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 808 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset Description 3 SS3 WO - SS3 Initiate Value Description 0 No effect. 1 Begin sampling on Sample Sequencer 3, if the sequencer is enabled in the ADCACTSS register. Only a write by software is valid; a read of this register returns no meaningful data. 2 SS2 WO - SS2 Initiate Value Description 0 No effect. 1 Begin sampling on Sample Sequencer 2, if the sequencer is enabled in the ADCACTSS register. Only a write by software is valid; a read of this register returns no meaningful data. 1 SS1 WO - SS1 Initiate Value Description 0 No effect. 1 Begin sampling on Sample Sequencer 1, if the sequencer is enabled in the ADCACTSS register. Only a write by software is valid; a read of this register returns no meaningful data. 0 SS0 WO - SS0 Initiate Value Description 0 No effect. 1 Begin sampling on Sample Sequencer 0, if the sequencer is enabled in the ADCACTSS register. Only a write by software is valid; a read of this register returns no meaningful data. June 12, 2014 809 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 11: ADC Sample Averaging Control (ADCSAC), offset 0x030 This register controls the amount of hardware averaging applied to conversion results. The final conversion result stored in the FIFO is averaged from 2 AVG consecutive ADC samples at the specified ADC speed. If AVG is 0, the sample is passed directly through without any averaging. If AVG=6, then 64 consecutive ADC samples are averaged to generate one result in the sequencer FIFO. An AVG=7 provides unpredictable results. ADC Sample Averaging Control (ADCSAC) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x030 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset 31:3 reserved RO 0x0000.000 2:0 AVG RW 0x0 AVG RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Hardware Averaging Control Specifies the amount of hardware averaging that will be applied to ADC samples. The AVG field can be any value between 0 and 6. Entering a value of 7 creates unpredictable results. Value Description 0x0 No hardware oversampling 0x1 2x hardware oversampling 0x2 4x hardware oversampling 0x3 8x hardware oversampling 0x4 16x hardware oversampling 0x5 32x hardware oversampling 0x6 64x hardware oversampling 0x7 reserved 810 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 12: ADC Digital Comparator Interrupt Status and Clear (ADCDCISC), offset 0x034 This register provides status and acknowledgement of digital comparator interrupts. One bit is provided for each comparator. ADC Digital Comparator Interrupt Status and Clear (ADCDCISC) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x034 Type RW1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 DCINT7 RW1C 0 RO 0 RO 0 7 6 5 4 3 2 1 0 DCINT7 DCINT6 DCINT5 DCINT4 DCINT3 DCINT2 DCINT1 DCINT0 RW1C 0 RW1C 0 RW1C 0 RW1C 0 RW1C 0 RW1C 0 RW1C 0 RW1C 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Digital Comparator 7 Interrupt Status and Clear Value Description 0 No interrupt. 1 Digital Comparator 7 has generated an interrupt. This bit is cleared by writing a 1. 6 DCINT6 RW1C 0 Digital Comparator 6 Interrupt Status and Clear Value Description 0 No interrupt. 1 Digital Comparator 6 has generated an interrupt. This bit is cleared by writing a 1. 5 DCINT5 RW1C 0 Digital Comparator 5 Interrupt Status and Clear Value Description 0 No interrupt. 1 Digital Comparator 5 has generated an interrupt. This bit is cleared by writing a 1. June 12, 2014 811 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 4 DCINT4 RW1C 0 Description Digital Comparator 4 Interrupt Status and Clear Value Description 0 No interrupt. 1 Digital Comparator 4 has generated an interrupt. This bit is cleared by writing a 1. 3 DCINT3 RW1C 0 Digital Comparator 3 Interrupt Status and Clear Value Description 0 No interrupt. 1 Digital Comparator 3 has generated an interrupt. This bit is cleared by writing a 1. 2 DCINT2 RW1C 0 Digital Comparator 2 Interrupt Status and Clear Value Description 0 No interrupt. 1 Digital Comparator 2 has generated an interrupt. This bit is cleared by writing a 1. 1 DCINT1 RW1C 0 Digital Comparator 1 Interrupt Status and Clear Value Description 0 No interrupt. 1 Digital Comparator 1 has generated an interrupt. This bit is cleared by writing a 1. 0 DCINT0 RW1C 0 Digital Comparator 0 Interrupt Status and Clear Value Description 0 No interrupt. 1 Digital Comparator 0 has generated an interrupt. This bit is cleared by writing a 1. 812 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 13: ADC Control (ADCCTL), offset 0x038 This register configures the voltage reference. Note that values set in this register apply to all ADC modules, it is not possible to set one module to use internal references and another to use external references. ADC Control (ADCCTL) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x038 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset DITHER RO 0 Bit/Field Name Type Reset 31:7 reserved RO 0x0000.000 6 DITHER RW 0 RW 0 reserved RO 0 VREF RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Dither Mode Enable Value Description 5:1 reserved RO 0 0 VREF RW 0x0 0 Dither mode disabled 1 Dither mode enabled Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Voltage Reference Select Value Description 0x0 VDDA and GNDA are the voltage references for all ADC modules. 0x1 Reserved June 12, 2014 813 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 14: ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0), offset 0x040 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 0. This register is 32 bits wide and contains information for eight possible samples. ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x040 Type RW, reset 0x0000.0000 31 30 29 28 27 26 MUX7 Type Reset RW 0 RW 0 15 14 RW 0 RW 0 RW 0 RW 0 13 12 11 10 MUX3 Type Reset RW 0 RW 0 25 24 23 22 MUX6 RW 0 RW 0 RW 0 RW 0 9 8 7 6 MUX2 RW 0 RW 0 RW 0 RW 0 21 20 19 18 MUX5 RW 0 RW 0 RW 0 RW 0 5 4 3 2 MUX1 RW 0 Bit/Field Name Type Reset 31:28 MUX7 RW 0x0 RW 0 RW 0 RW 0 17 16 RW 0 RW 0 1 0 RW 0 RW 0 MUX4 MUX0 RW 0 RW 0 RW 0 RW 0 Description 8th Sample Input Select The MUX7 field is used during the eighth sample of a sequence executed with the sample sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. The value set here indicates the corresponding pin, for example, a value of 0x1 indicates the input is AIN1. 27:24 MUX6 RW 0x0 7th Sample Input Select The MUX6 field is used during the seventh sample of a sequence executed with the sample sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. 23:20 MUX5 RW 0x0 6th Sample Input Select The MUX5 field is used during the sixth sample of a sequence executed with the sample sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. 19:16 MUX4 RW 0x0 5th Sample Input Select The MUX4 field is used during the fifth sample of a sequence executed with the sample sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. 15:12 MUX3 RW 0x0 4th Sample Input Select The MUX3 field is used during the fourth sample of a sequence executed with the sample sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. 11:8 MUX2 RW 0x0 3rd Sample Input Select The MUX2 field is used during the third sample of a sequence executed with the sample sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. 814 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 7:4 MUX1 RW 0x0 Description 2nd Sample Input Select The MUX1 field is used during the second sample of a sequence executed with the sample sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. 3:0 MUX0 RW 0x0 1st Sample Input Select The MUX0 field is used during the first sample of a sequence executed with the sample sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. June 12, 2014 815 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 15: ADC Sample Sequence Control 0 (ADCSSCTL0), offset 0x044 This register contains the configuration information for each sample for a sequence executed with a sample sequencer. When configuring a sample sequence, the END bit must be set for the final sample, whether it be after the first sample, eighth sample, or any sample in between. This register is 32 bits wide and contains information for eight possible samples. ADC Sample Sequence Control 0 (ADCSSCTL0) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x044 Type RW, reset 0x0000.0000 31 Type Reset Type Reset 30 29 28 27 26 25 TS7 IE7 RW 0 RW 0 15 24 23 END7 D7 RW 0 RW 0 14 13 TS3 IE3 RW 0 RW 0 22 21 TS6 IE6 RW 0 RW 0 12 11 END3 D3 RW 0 RW 0 END6 D6 RW 0 RW 0 TS5 IE5 RW 0 RW 0 10 9 8 7 TS2 IE2 RW 0 RW 0 END2 D2 RW 0 RW 0 Bit/Field Name Type Reset 31 TS7 RW 0 20 19 18 17 END5 D5 RW 0 RW 0 6 5 TS1 IE1 RW 0 RW 0 16 TS4 IE4 END4 D4 RW 0 RW 0 RW 0 RW 0 4 3 2 1 0 END1 D1 TS0 IE0 END0 D0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 Description 8th Sample Temp Sensor Select Value Description 30 IE7 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the eighth sample of the sample sequence. 1 The temperature sensor is read during the eighth sample of the sample sequence. 8th Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the eighth sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 29 END7 RW 0 8th Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The eighth sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 816 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 28 D7 RW 0 Description 8th Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS7 bit is set. 27 TS6 RW 0 7th Sample Temp Sensor Select Value Description 26 IE6 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the seventh sample of the sample sequence. 1 The temperature sensor is read during the seventh sample of the sample sequence. 7th Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the seventh sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 25 END6 RW 0 7th Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The seventh sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 24 D6 RW 0 7th Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS6 bit is set. June 12, 2014 817 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 23 TS5 RW 0 Description 6th Sample Temp Sensor Select Value Description 22 IE5 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the sixth sample of the sample sequence. 1 The temperature sensor is read during the sixth sample of the sample sequence. 6th Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the sixth sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 21 END5 RW 0 6th Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The sixth sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 20 D5 RW 0 6th Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS5 bit is set. 19 TS4 RW 0 5th Sample Temp Sensor Select Value Description 0 The input pin specified by the ADCSSMUXn register is read during the fifth sample of the sample sequence. 1 The temperature sensor is read during the fifth sample of the sample sequence. 818 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 18 IE4 RW 0 Description 5th Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the fifth sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 17 END4 RW 0 5th Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The fifth sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 16 D4 RW 0 5th Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS4 bit is set. 15 TS3 RW 0 4th Sample Temp Sensor Select Value Description 14 IE3 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the fourth sample of the sample sequence. 1 The temperature sensor is read during the fourth sample of the sample sequence. 4th Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the fourth sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. June 12, 2014 819 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 13 END3 RW 0 Description 4th Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The fourth sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 12 D3 RW 0 4th Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS3 bit is set. 11 TS2 RW 0 3rd Sample Temp Sensor Select Value Description 10 IE2 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the third sample of the sample sequence. 1 The temperature sensor is read during the third sample of the sample sequence. 3rd Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the third sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 9 END2 RW 0 3rd Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The third sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 820 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 8 D2 RW 0 Description 3rd Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS2 bit is set. 7 TS1 RW 0 2nd Sample Temp Sensor Select Value Description 6 IE1 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the second sample of the sample sequence. 1 The temperature sensor is read during the second sample of the sample sequence. 2nd Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the second sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 5 END1 RW 0 2nd Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The second sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 4 D1 RW 0 2nd Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS1 bit is set. June 12, 2014 821 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 3 TS0 RW 0 Description 1st Sample Temp Sensor Select Value Description 2 IE0 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the first sample of the sample sequence. 1 The temperature sensor is read during the first sample of the sample sequence. 1st Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the first sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 1 END0 RW 0 1st Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The first sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 0 D0 RW 0 1st Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS0 bit is set. 822 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 16: ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0), offset 0x048 Register 17: ADC Sample Sequence Result FIFO 1 (ADCSSFIFO1), offset 0x068 Register 18: ADC Sample Sequence Result FIFO 2 (ADCSSFIFO2), offset 0x088 Register 19: ADC Sample Sequence Result FIFO 3 (ADCSSFIFO3), offset 0x0A8 Important: This register is read-sensitive. See the register description for details. This register contains the conversion results for samples collected with the sample sequencer (the ADCSSFIFO0 register is used for Sample Sequencer 0, ADCSSFIFO1 for Sequencer 1, ADCSSFIFO2 for Sequencer 2, and ADCSSFIFO3 for Sequencer 3). Reads of this register return conversion result data in the order sample 0, sample 1, and so on, until the FIFO is empty. If the FIFO is not properly handled by software, overflow and underflow conditions are registered in the ADCOSTAT and ADCUSTAT registers. ADC Sample Sequence Result FIFO n (ADCSSFIFOn) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x048 Type RO, reset 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 5 4 3 2 1 0 RO - RO - RO - RO - RO - RO - reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 reserved Type Reset RO 0 RO 0 DATA RO 0 RO 0 RO - RO - RO - Bit/Field Name Type Reset 31:12 reserved RO 0x0000.0 11:0 DATA RO - RO - RO - RO - Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Conversion Result Data June 12, 2014 823 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 20: ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0), offset 0x04C Register 21: ADC Sample Sequence FIFO 1 Status (ADCSSFSTAT1), offset 0x06C Register 22: ADC Sample Sequence FIFO 2 Status (ADCSSFSTAT2), offset 0x08C Register 23: ADC Sample Sequence FIFO 3 Status (ADCSSFSTAT3), offset 0x0AC This register provides a window into the sample sequencer, providing full/empty status information as well as the positions of the head and tail pointers. The reset value of 0x100 indicates an empty FIFO with the head and tail pointers both pointing to index 0. The ADCSSFSTAT0 register provides status on FIFO0, which has 8 entries; ADCSSFSTAT1 on FIFO1, which has 4 entries; ADCSSFSTAT2 on FIFO2, which has 4 entries; and ADCSSFSTAT3 on FIFO3 which has a single entry. ADC Sample Sequence FIFO n Status (ADCSSFSTATn) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x04C Type RO, reset 0x0000.0100 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 RO 0 FULL RO 0 RO 0 reserved RO 0 RO 0 EMPTY RO 0 Bit/Field Name Type Reset 31:13 reserved RO 0x0000.0 12 FULL RO 0 RO 1 HPTR TPTR Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. FIFO Full Value Description 11:9 reserved RO 0x0 8 EMPTY RO 1 0 The FIFO is not currently full. 1 The FIFO is currently full. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. FIFO Empty Value Description 0 The FIFO is not currently empty. 1 The FIFO is currently empty. 824 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 7:4 HPTR RO 0x0 Description FIFO Head Pointer This field contains the current "head" pointer index for the FIFO, that is, the next entry to be written. Valid values are 0x0-0x7 for FIFO0; 0x0-0x3 for FIFO1 and FIFO2; and 0x0 for FIFO3. 3:0 TPTR RO 0x0 FIFO Tail Pointer This field contains the current "tail" pointer index for the FIFO, that is, the next entry to be read. Valid values are 0x0-0x7 for FIFO0; 0x0-0x3 for FIFO1 and FIFO2; and 0x0 for FIFO3. June 12, 2014 825 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 24: ADC Sample Sequence 0 Operation (ADCSSOP0), offset 0x050 This register determines whether the sample from the given conversion on Sample Sequence 0 is saved in the Sample Sequence FIFO0 or sent to the digital comparator unit. ADC Sample Sequence 0 Operation (ADCSSOP0) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x050 Type RW, reset 0x0000.0000 31 30 29 reserved Type Reset 27 S7DCOP 26 25 reserved 24 23 S6DCOP 22 21 reserved 20 19 S5DCOP 18 17 reserved 16 S4DCOP RO 0 RO 0 RO 0 RW 0 RO 0 RO 0 RO 0 RW 0 RO 0 RO 0 RO 0 RW 0 RO 0 RO 0 RO 0 RW 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 reserved Type Reset 28 RO 0 RO 0 S3DCOP RO 0 RW 0 reserved RO 0 RO 0 S2DCOP RO 0 Bit/Field Name Type Reset 31:29 reserved RO 0x0 28 S7DCOP RW 0 RW 0 reserved RO 0 RO 0 S1DCOP RO 0 RW 0 reserved RO 0 RO 0 S0DCOP RO 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 7 Digital Comparator Operation Value Description 27:25 reserved RO 0x0 24 S6DCOP RW 0 0 The eighth sample is saved in Sample Sequence FIFO0. 1 The eighth sample is sent to the digital comparator unit specified by the S7DCSEL bit in the ADCSSDC0 register, and the value is not written to the FIFO. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 6 Digital Comparator Operation Same definition as S7DCOP but used during the seventh sample. 23:21 reserved RO 0x0 20 S5DCOP RW 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 5 Digital Comparator Operation Same definition as S7DCOP but used during the sixth sample. 19:17 reserved RO 0x0 16 S4DCOP RW 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 4 Digital Comparator Operation Same definition as S7DCOP but used during the fifth sample. 15:13 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 826 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 12 S3DCOP RW 0 Description Sample 3 Digital Comparator Operation Same definition as S7DCOP but used during the fourth sample. 11:9 reserved RO 0x0 8 S2DCOP RW 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 2 Digital Comparator Operation Same definition as S7DCOP but used during the third sample. 7:5 reserved RO 0x0 4 S1DCOP RW 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 1 Digital Comparator Operation Same definition as S7DCOP but used during the second sample. 3:1 reserved RO 0x0 0 S0DCOP RW 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 0 Digital Comparator Operation Same definition as S7DCOP but used during the first sample. June 12, 2014 827 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 25: ADC Sample Sequence 0 Digital Comparator Select (ADCSSDC0), offset 0x054 This register determines which digital comparator receives the sample from the given conversion on Sample Sequence 0, if the corresponding SnDCOP bit in the ADCSSOP0 register is set. ADC Sample Sequence 0 Digital Comparator Select (ADCSSDC0) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x054 Type RW, reset 0x0000.0000 31 30 29 28 27 26 S7DCSEL Type Reset 24 23 22 21 20 19 S5DCSEL 18 17 16 S4DCSEL RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 S3DCSEL Type Reset 25 S6DCSEL RW 0 RW 0 S2DCSEL RW 0 RW 0 RW 0 RW 0 RW 0 Bit/Field Name Type Reset 31:28 S7DCSEL RW 0x0 S1DCSEL RW 0 RW 0 RW 0 RW 0 S0DCSEL RW 0 RW 0 RW 0 RW 0 RW 0 Description Sample 7 Digital Comparator Select When the S7DCOP bit in the ADCSSOP0 register is set, this field indicates which digital comparator unit (and its associated set of control registers) receives the eighth sample from Sample Sequencer 0. Note: Values not listed are reserved. Value Description 27:24 S6DCSEL RW 0x0 0x0 Digital Comparator Unit 0 (ADCDCCMP0 and ADCDCCTL0) 0x1 Digital Comparator Unit 1 (ADCDCCMP1 and ADCDCCTL1) 0x2 Digital Comparator Unit 2 (ADCDCCMP2 and ADCDCCTL2) 0x3 Digital Comparator Unit 3 (ADCDCCMP3 and ADCDCCTL3) 0x4 Digital Comparator Unit 4 (ADCDCCMP4 and ADCDCCTL4) 0x5 Digital Comparator Unit 5 (ADCDCCMP5 and ADCDCCTL5) 0x6 Digital Comparator Unit 6 (ADCDCCMP6 and ADCDCCTL6) 0x7 Digital Comparator Unit 7 (ADCDCCMP7 and ADCDCCTL7) Sample 6 Digital Comparator Select This field has the same encodings as S7DCSEL but is used during the seventh sample. 23:20 S5DCSEL RW 0x0 Sample 5 Digital Comparator Select This field has the same encodings as S7DCSEL but is used during the sixth sample. 19:16 S4DCSEL RW 0x0 Sample 4 Digital Comparator Select This field has the same encodings as S7DCSEL but is used during the fifth sample. 15:12 S3DCSEL RW 0x0 Sample 3 Digital Comparator Select This field has the same encodings as S7DCSEL but is used during the fourth sample. 828 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 11:8 S2DCSEL RW 0x0 Description Sample 2 Digital Comparator Select This field has the same encodings as S7DCSEL but is used during the third sample. 7:4 S1DCSEL RW 0x0 Sample 1 Digital Comparator Select This field has the same encodings as S7DCSEL but is used during the second sample. 3:0 S0DCSEL RW 0x0 Sample 0 Digital Comparator Select This field has the same encodings as S7DCSEL but is used during the first sample. June 12, 2014 829 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 26: ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1), offset 0x060 Register 27: ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2), offset 0x080 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 1 or 2. These registers are 16 bits wide and contain information for four possible samples. See the ADCSSMUX0 register on page 814 for detailed bit descriptions. The ADCSSMUX1 register affects Sample Sequencer 1 and the ADCSSMUX2 register affects Sample Sequencer 2. ADC Sample Sequence Input Multiplexer Select n (ADCSSMUXn) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x060 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset MUX3 Type Reset MUX2 MUX1 MUX0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 15:12 MUX3 RW 0x0 4th Sample Input Select 11:8 MUX2 RW 0x0 3rd Sample Input Select 7:4 MUX1 RW 0x0 2nd Sample Input Select 3:0 MUX0 RW 0x0 1st Sample Input Select Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 830 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 28: ADC Sample Sequence Control 1 (ADCSSCTL1), offset 0x064 Register 29: ADC Sample Sequence Control 2 (ADCSSCTL2), offset 0x084 These registers contain the configuration information for each sample for a sequence executed with Sample Sequencer 1 or 2. When configuring a sample sequence, the END bit must be set for the final sample, whether it be after the first sample, fourth sample, or any sample in between. These registers are 16-bits wide and contain information for four possible samples. See the ADCSSCTL0 register on page 816 for detailed bit descriptions. The ADCSSCTL1 register configures Sample Sequencer 1 and the ADCSSCTL2 register configures Sample Sequencer 2. ADC Sample Sequence Control n (ADCSSCTLn) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x064 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 TS3 IE3 END3 D3 TS2 IE2 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 END2 D2 TS1 IE1 END1 D1 TS0 IE0 END0 D0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 TS3 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4th Sample Temp Sensor Select Value Description 14 IE3 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the fourth sample of the sample sequence. 1 The temperature sensor is read during the fourth sample of the sample sequence. 4th Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the fourth sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. June 12, 2014 831 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 13 END3 RW 0 Description 4th Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The fourth sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 12 D3 RW 0 4th Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS3 bit is set. 11 TS2 RW 0 3rd Sample Temp Sensor Select Value Description 10 IE2 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the third sample of the sample sequence. 1 The temperature sensor is read during the third sample of the sample sequence. 3rd Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the third sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 9 END2 RW 0 3rd Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The third sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 832 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 8 D2 RW 0 Description 3rd Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS2 bit is set. 7 TS1 RW 0 2nd Sample Temp Sensor Select Value Description 6 IE1 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the second sample of the sample sequence. 1 The temperature sensor is read during the second sample of the sample sequence. 2nd Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the second sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 5 END1 RW 0 2nd Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The second sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 4 D1 RW 0 2nd Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS1 bit is set. June 12, 2014 833 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 3 TS0 RW 0 Description 1st Sample Temp Sensor Select Value Description 2 IE0 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the first sample of the sample sequence. 1 The temperature sensor is read during the first sample of the sample sequence. 1st Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of the first sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 1 END0 RW 0 1st Sample is End of Sequence Value Description 0 Another sample in the sequence is the final sample. 1 The first sample is the last sample of the sequence. It is possible to end the sequence on any sample position. Software must set an ENDn bit somewhere within the sequence. Samples defined after the sample containing a set ENDn bit are not requested for conversion even though the fields may be non-zero. 0 D0 RW 0 1st Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS0 bit is set. 834 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 30: ADC Sample Sequence 1 Operation (ADCSSOP1), offset 0x070 Register 31: ADC Sample Sequence 2 Operation (ADCSSOP2), offset 0x090 This register determines whether the sample from the given conversion on Sample Sequence n is saved in the Sample Sequence n FIFO or sent to the digital comparator unit. The ADCSSOP1 register controls Sample Sequencer 1 and the ADCSSOP2 register controls Sample Sequencer 2. ADC Sample Sequence n Operation (ADCSSOPn) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x070 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 reserved Type Reset reserved Type Reset RO 0 RO 0 S3DCOP RO 0 RW 0 reserved RO 0 RO 0 S2DCOP RO 0 Bit/Field Name Type Reset 31:13 reserved RO 0x0000.0 12 S3DCOP RW 0 RW 0 reserved RO 0 RO 0 S1DCOP RO 0 RW 0 reserved RO 0 RO 0 S0DCOP RO 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 3 Digital Comparator Operation Value Description 11:9 reserved RO 0x0 8 S2DCOP RW 0 0 The fourth sample is saved in Sample Sequence FIFOn. 1 The fourth sample is sent to the digital comparator unit specified by the S3DCSEL bit in the ADCSSDC0n register, and the value is not written to the FIFO. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 2 Digital Comparator Operation Same definition as S3DCOP but used during the third sample. 7:5 reserved RO 0x0 4 S1DCOP RW 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 1 Digital Comparator Operation Same definition as S3DCOP but used during the second sample. 3:1 reserved RO 0x0 0 S0DCOP RW 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 0 Digital Comparator Operation Same definition as S3DCOP but used during the first sample. June 12, 2014 835 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 32: ADC Sample Sequence 1 Digital Comparator Select (ADCSSDC1), offset 0x074 Register 33: ADC Sample Sequence 2 Digital Comparator Select (ADCSSDC2), offset 0x094 These registers determine which digital comparator receives the sample from the given conversion on Sample Sequence n if the corresponding SnDCOP bit in the ADCSSOPn register is set. The ADCSSDC1 register controls the selection for Sample Sequencer 1 and the ADCSSDC2 register controls the selection for Sample Sequencer 2. ADC Sample Sequence n Digital Comparator Select (ADCSSDCn) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x074 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RW 0 RW 0 RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset S3DCSEL Type Reset S2DCSEL RW 0 RW 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:12 S3DCSEL RW 0x0 S1DCSEL RW 0 S0DCSEL RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 3 Digital Comparator Select When the S3DCOP bit in the ADCSSOPn register is set, this field indicates which digital comparator unit (and its associated set of control registers) receives the eighth sample from Sample Sequencer n. Note: Values not listed are reserved. Value Description 11:8 S2DCSEL RW 0x0 0x0 Digital Comparator Unit 0 (ADCDCCMP0 and ADCCCTL0) 0x1 Digital Comparator Unit 1 (ADCDCCMP1 and ADCCCTL1) 0x2 Digital Comparator Unit 2 (ADCDCCMP2 and ADCCCTL2) 0x3 Digital Comparator Unit 3 (ADCDCCMP3 and ADCCCTL3) 0x4 Digital Comparator Unit 4 (ADCDCCMP4 and ADCCCTL4) 0x5 Digital Comparator Unit 5 (ADCDCCMP5 and ADCCCTL5) 0x6 Digital Comparator Unit 6 (ADCDCCMP6 and ADCCCTL6) 0x7 Digital Comparator Unit 7 (ADCDCCMP7 and ADCCCTL7) Sample 2 Digital Comparator Select This field has the same encodings as S3DCSEL but is used during the third sample. 836 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 7:4 S1DCSEL RW 0x0 Description Sample 1 Digital Comparator Select This field has the same encodings as S3DCSEL but is used during the second sample. 3:0 S0DCSEL RW 0x0 Sample 0 Digital Comparator Select This field has the same encodings as S3DCSEL but is used during the first sample. June 12, 2014 837 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 34: ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3), offset 0x0A0 This register defines the analog input configuration for the sample executed with Sample Sequencer 3. This register is 4 bits wide and contains information for one possible sample. See the ADCSSMUX0 register on page 814 for detailed bit descriptions. ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x0A0 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 1 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 MUX0 RO 0 Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3:0 MUX0 RW 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1st Sample Input Select 838 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 35: ADC Sample Sequence Control 3 (ADCSSCTL3), offset 0x0A4 This register contains the configuration information for a sample executed with Sample Sequencer 3. This register is 4 bits wide and contains information for one possible sample. See the ADCSSCTL0 register on page 816 for detailed bit descriptions. Note: When configuring a sample sequence in this register, the END0 bit must be set. ADC Sample Sequence Control 3 (ADCSSCTL3) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x0A4 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3 TS0 RW 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 1 0 TS0 IE0 END0 D0 RW 0 RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1st Sample Temp Sensor Select Value Description 2 IE0 RW 0 0 The input pin specified by the ADCSSMUXn register is read during the first sample of the sample sequence. 1 The temperature sensor is read during the first sample of the sample sequence. Sample Interrupt Enable Value Description 0 The raw interrupt is not asserted to the interrupt controller. 1 The raw interrupt signal (INR0 bit) is asserted at the end of this sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to the interrupt controller. It is legal to have multiple samples within a sequence generate interrupts. 1 END0 RW 0 End of Sequence This bit must be set before initiating a single sample sequence. Value Description 0 Sampling and conversion continues. 1 This is the end of sequence. June 12, 2014 839 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 0 D0 RW 0 Description Sample Differential Input Select Value Description 0 The analog inputs are not differentially sampled. 1 The analog input is differentially sampled. The corresponding ADCSSMUXn nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". Because the temperature sensor does not have a differential option, this bit must not be set when the TS0 bit is set. 840 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 36: ADC Sample Sequence 3 Operation (ADCSSOP3), offset 0x0B0 This register determines whether the sample from the given conversion on Sample Sequence 3 is saved in the Sample Sequence 3 FIFO or sent to the digital comparator unit. ADC Sample Sequence 3 Operation (ADCSSOP3) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x0B0 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:1 reserved RO 0x0000.000 0 S0DCOP RW 0 RO 0 S0DCOP RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 0 Digital Comparator Operation Value Description 0 The sample is saved in Sample Sequence FIFO3. 1 The sample is sent to the digital comparator unit specified by the S0DCSEL bit in the ADCSSDC03 register, and the value is not written to the FIFO. June 12, 2014 841 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 37: ADC Sample Sequence 3 Digital Comparator Select (ADCSSDC3), offset 0x0B4 This register determines which digital comparator receives the sample from the given conversion on Sample Sequence 3 if the corresponding SnDCOP bit in the ADCSSOP3 register is set. ADC Sample Sequence 3 Digital Comparator Select (ADCSSDC3) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0x0B4 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3:0 S0DCSEL RW 0x0 S0DCSEL RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Sample 0 Digital Comparator Select When the S0DCOP bit in the ADCSSOP3 register is set, this field indicates which digital comparator unit (and its associated set of control registers) receives the sample from Sample Sequencer 3. Note: Values not listed are reserved. Value Description 0x0 Digital Comparator Unit 0 (ADCDCCMP0 and ADCCCTL0) 0x1 Digital Comparator Unit 1 (ADCDCCMP1 and ADCCCTL1) 0x2 Digital Comparator Unit 2 (ADCDCCMP2 and ADCCCTL2) 0x3 Digital Comparator Unit 3 (ADCDCCMP3 and ADCCCTL3) 0x4 Digital Comparator Unit 4 (ADCDCCMP4 and ADCCCTL4) 0x5 Digital Comparator Unit 5 (ADCDCCMP5 and ADCCCTL5) 0x6 Digital Comparator Unit 6 (ADCDCCMP6 and ADCCCTL6) 0x7 Digital Comparator Unit 7 (ADCDCCMP7 and ADCCCTL7) 842 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 38: ADC Digital Comparator Reset Initial Conditions (ADCDCRIC), offset 0xD00 This register provides the ability to reset any of the digital comparator interrupt or trigger functions back to their initial conditions. Resetting these functions ensures that the data that is being used by the interrupt and trigger functions in the digital comparator unit is not stale. ADC Digital Comparator Reset Initial Conditions (ADCDCRIC) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0xD00 Type WO, reset 0x0000.0000 31 30 29 28 27 26 25 24 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 reserved Type Reset RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 DCTRIG7 DCTRIG6 DCTRIG5 DCTRIG4 DCTRIG3 DCTRIG2 DCTRIG1 DCTRIG0 RO 0 RO 0 RO 0 RO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 7 6 5 4 3 2 1 0 DCINT7 DCINT6 DCINT5 DCINT4 DCINT3 DCINT2 DCINT1 DCINT0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 Bit/Field Name Type Reset Description 31:24 reserved RO 0x00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 23 DCTRIG7 WO 0 Digital Comparator Trigger 7 Value Description 0 No effect. 1 Resets the Digital Comparator 7 trigger unit to its initial conditions. When the trigger has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the trigger, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. After setting this bit, software should wait until the bit clears before continuing. 22 DCTRIG6 WO 0 Digital Comparator Trigger 6 Value Description 0 No effect. 1 Resets the Digital Comparator 6 trigger unit to its initial conditions. When the trigger has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the trigger, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. June 12, 2014 843 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 21 DCTRIG5 WO 0 Description Digital Comparator Trigger 5 Value Description 0 No effect. 1 Resets the Digital Comparator 5 trigger unit to its initial conditions. When the trigger has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the trigger, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 20 DCTRIG4 WO 0 Digital Comparator Trigger 4 Value Description 0 No effect. 1 Resets the Digital Comparator 4 trigger unit to its initial conditions. When the trigger has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the trigger, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 19 DCTRIG3 WO 0 Digital Comparator Trigger 3 Value Description 0 No effect. 1 Resets the Digital Comparator 3 trigger unit to its initial conditions. When the trigger has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the trigger, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 18 DCTRIG2 WO 0 Digital Comparator Trigger 2 Value Description 0 No effect. 1 Resets the Digital Comparator 2 trigger unit to its initial conditions. When the trigger has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the trigger, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 844 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 17 DCTRIG1 WO 0 Description Digital Comparator Trigger 1 Value Description 0 No effect. 1 Resets the Digital Comparator 1 trigger unit to its initial conditions. When the trigger has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the trigger, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 16 DCTRIG0 WO 0 Digital Comparator Trigger 0 Value Description 0 No effect. 1 Resets the Digital Comparator 0 trigger unit to its initial conditions. When the trigger has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the trigger, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 15:8 reserved RO 0x00 7 DCINT7 WO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Digital Comparator Interrupt 7 Value Description 0 No effect. 1 Resets the Digital Comparator 7 interrupt unit to its initial conditions. When the interrupt has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the interrupt, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 6 DCINT6 WO 0 Digital Comparator Interrupt 6 Value Description 0 No effect. 1 Resets the Digital Comparator 6 interrupt unit to its initial conditions. When the interrupt has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the interrupt, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. June 12, 2014 845 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 5 DCINT5 WO 0 Description Digital Comparator Interrupt 5 Value Description 0 No effect. 1 Resets the Digital Comparator 5 interrupt unit to its initial conditions. When the interrupt has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the interrupt, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 4 DCINT4 WO 0 Digital Comparator Interrupt 4 Value Description 0 No effect. 1 Resets the Digital Comparator 4 interrupt unit to its initial conditions. When the interrupt has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the interrupt, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 3 DCINT3 WO 0 Digital Comparator Interrupt 3 Value Description 0 No effect. 1 Resets the Digital Comparator 3 interrupt unit to its initial conditions. When the interrupt has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the interrupt, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 2 DCINT2 WO 0 Digital Comparator Interrupt 2 Value Description 0 No effect. 1 Resets the Digital Comparator 2 interrupt unit to its initial conditions. When the interrupt has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the interrupt, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 846 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 1 DCINT1 WO 0 Description Digital Comparator Interrupt 1 Value Description 0 No effect. 1 Resets the Digital Comparator 1 interrupt unit to its initial conditions. When the interrupt has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the interrupt, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. 0 DCINT0 WO 0 Digital Comparator Interrupt 0 Value Description 0 No effect. 1 Resets the Digital Comparator 0 interrupt unit to its initial conditions. When the interrupt has been cleared, this bit is automatically cleared. Because the digital comparators use the current and previous ADC conversion values to determine when to assert the interrupt, it is important to reset the digital comparator to initial conditions when starting a new sequence so that stale data is not used. June 12, 2014 847 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 39: ADC Digital Comparator Control 0 (ADCDCCTL0), offset 0xE00 Register 40: ADC Digital Comparator Control 1 (ADCDCCTL1), offset 0xE04 Register 41: ADC Digital Comparator Control 2 (ADCDCCTL2), offset 0xE08 Register 42: ADC Digital Comparator Control 3 (ADCDCCTL3), offset 0xE0C Register 43: ADC Digital Comparator Control 4 (ADCDCCTL4), offset 0xE10 Register 44: ADC Digital Comparator Control 5 (ADCDCCTL5), offset 0xE14 Register 45: ADC Digital Comparator Control 6 (ADCDCCTL6), offset 0xE18 Register 46: ADC Digital Comparator Control 7 (ADCDCCTL7), offset 0xE1C This register provides the comparison encodings that generate an interrupt. ADC Digital Comparator Control n (ADCDCCTLn) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0xE00 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 reserved Type Reset reserved Type Reset RO 0 CIE Bit/Field Name Type Reset 31:5 reserved RO 0x0000.0 4 CIE RW 0 RW 0 CIC RW 0 CIM RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Comparison Interrupt Enable Value Description 0 Disables the comparison interrupt. ADC conversion data has no effect on interrupt generation. 1 Enables the comparison interrupt. The ADC conversion data is used to determine if an interrupt should be generated according to the programming of the CIC and CIM fields. 848 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 3:2 CIC RW 0x0 Description Comparison Interrupt Condition This field specifies the operational region in which an interrupt is generated when the ADC conversion data is compared against the values of COMP0 and COMP1. The COMP0 and COMP1 fields are defined in the ADCDCCMPx registers. Value Description 0x0 Low Band ADC Data < COMP0 ≤ COMP1 0x1 Mid Band COMP0 ≤ ADC Data < COMP1 0x2 reserved 0x3 High Band COMP0 < COMP1 ≤ ADC Data 1:0 CIM RW 0x0 Comparison Interrupt Mode This field specifies the mode by which the interrupt comparison is made. Value Description 0x0 Always This mode generates an interrupt every time the ADC conversion data falls within the selected operational region. 0x1 Once This mode generates an interrupt the first time that the ADC conversion data enters the selected operational region. 0x2 Hysteresis Always This mode generates an interrupt when the ADC conversion data falls within the selected operational region and continues to generate the interrupt until the hysteresis condition is cleared by entering the opposite operational region. 0x3 Hysteresis Once This mode generates an interrupt the first time that the ADC conversion data falls within the selected operational region. No additional interrupts are generated until the hysteresis condition is cleared by entering the opposite operational region. June 12, 2014 849 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 47: ADC Digital Comparator Range 0 (ADCDCCMP0), offset 0xE40 Register 48: ADC Digital Comparator Range 1 (ADCDCCMP1), offset 0xE44 Register 49: ADC Digital Comparator Range 2 (ADCDCCMP2), offset 0xE48 Register 50: ADC Digital Comparator Range 3 (ADCDCCMP3), offset 0xE4C Register 51: ADC Digital Comparator Range 4 (ADCDCCMP4), offset 0xE50 Register 52: ADC Digital Comparator Range 5 (ADCDCCMP5), offset 0xE54 Register 53: ADC Digital Comparator Range 6 (ADCDCCMP6), offset 0xE58 Register 54: ADC Digital Comparator Range 7 (ADCDCCMP7), offset 0xE5C This register defines the comparison values that are used to determine if the ADC conversion data falls in the appropriate operating region. Note: The value in the COMP1 field must be greater than or equal to the value in the COMP0 field or unexpected results can occur. ADC Digital Comparator Range n (ADCDCCMPn) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0xE40 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 reserved Type Reset 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset 21 COMP1 RO 0 RO 0 COMP0 RO 0 RO 0 RW 0 RW 0 RW 0 Bit/Field Name Type Reset 31:28 reserved RO 0x0 27:16 COMP1 RW 0x000 RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Compare 1 The value in this field is compared against the ADC conversion data. The result of the comparison is used to determine if the data lies within the high-band region. Note that the value of COMP1 must be greater than or equal to the value of COMP0. 15:12 reserved RO 0x0 11:0 COMP0 RW 0x000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Compare 0 The value in this field is compared against the ADC conversion data. The result of the comparison is used to determine if the data lies within the low-band region. 850 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 55: ADC Peripheral Properties (ADCPP), offset 0xFC0 The ADCPP register provides information regarding the properties of the ADC module. ADC Peripheral Properties (ADCPP) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0xFC0 Type RO, reset 0x00B0.20C7 31 30 29 28 RO 0 RO 0 RO 0 RO 0 15 14 13 RO 0 RO 0 RO 1 27 26 25 24 23 22 21 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 1 12 11 10 9 8 7 6 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 reserved Type Reset DC Type Reset 19 18 17 RO 1 RO 0 RO 0 RO 0 RO 0 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 1 TS 20 RSL TYPE CH Bit/Field Name Type Reset 31:24 reserved RO 0 23 TS RO 0x1 16 MSR Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Temperature Sensor Value Description 0 The ADC module does not have a temperature sensor. 1 The ADC module has a temperature sensor. This field provides the similar information as the legacy DC1 register TEMPSNS bit. 22:18 RSL RO 0xC Resolution This field specifies the maximum number of binary bits used to represent the converted sample. The field is encoded as a binary value, in the range of 0 to 32 bits. 17:16 TYPE RO 0x0 ADC Architecture Value Description 0x0 SAR 0x1 - 0x3 Reserved 15:10 DC RO 0x8 Digital Comparator Count This field specifies the number of ADC digital comparators available to the converter. The field is encoded as a binary value, in the range of 0 to 63. This field provides similar information to the legacy DC9 register ADCnDCn bits. June 12, 2014 851 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset 9:4 CH RO 0xC Description ADC Channel Count This field specifies the number of ADC input channels available to the converter. This field is encoded as a binary value, in the range of 0 to 63. This field provides similar information to the legacy DC3 and DC8 register ADCnAINn bits. 3:0 MSR RO 0x7 Maximum ADC Sample Rate This field specifies the maximum number of ADC conversions per second. The MSR field is encoded as follows: Value Description 0x0 Reserved 0x1 125 ksps 0x2 Reserved 0x3 250 ksps 0x4 Reserved 0x5 500 ksps 0x6 Reserved 0x7 1 Msps 0x8 - 0xF Reserved 852 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 56: ADC Peripheral Configuration (ADCPC), offset 0xFC4 The ADCPC register provides information regarding the configuration of the peripheral. ADC Peripheral Configuration (ADCPC) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0xFC4 Type RW, reset 0x0000.0007 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 1 RW 1 RW 1 reserved Type Reset reserved Type Reset Bit/Field Name Type 31:4 reserved RO 3:0 SR RW Reset SR Description 0x0000.0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0x7 ADC Sample Rate This field specifies the number of ADC conversions per second and is used in Run, Sleep, and Deep-Sleep modes. The field encoding is based on the legacy RCGC0 register encoding. The programmed sample rate cannot exceed the maximum sample rate specified by the MSR field in the ADCPP register. The SR field is encoded as follows: Value Description 0x0 Reserved 0x1 125 ksps 0x2 Reserved 0x3 250 ksps 0x4 Reserved 0x5 500 ksps 0x6 Reserved 0x7 1 Msps 0x8 - 0xF Reserved June 12, 2014 853 Texas Instruments-Production Data Analog-to-Digital Converter (ADC) Register 57: ADC Clock Configuration (ADCCC), offset 0xFC8 The ADCCC register controls the clock source for the ADC module. To use the PIOSC to clock the ADC, first power up the PLL and then enable the PIOSC in the CS bit field, then disable the PLL. To use the MOSC to clock the ADC, first power up the PLL and then enable the clock to the ADC module, then disable the PLL and switch to the MOSC for the system clock. ADC Clock Configuration (ADCCC) ADC0 base: 0x4003.8000 ADC1 base: 0x4003.9000 Offset 0xFC8 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset CS Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3:0 CS RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. ADC Clock Source The following table specifies the clock source that generates the ADC clock input, see Figure 5-5 on page 211. Value Description 0x0 Either the 16-MHz system clock (if the PLL bypass is in effect) or the 16 MHz clock derived from PLL ÷ 25 (default). Note that when the PLL is bypassed, the system clock must be at least 16 MHz. 0x1 PIOSC The PIOSC provides a 16-MHz clock source for the ADC. If the PIOSC is used as the clock source, the ADC module can continue to operate in Deep-Sleep mode. 0x2 - 0xF Reserved 854 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 14 Universal Asynchronous Receivers/Transmitters (UARTs) The TM4C1231H6PM controller includes eight Universal Asynchronous Receiver/Transmitter (UART) with the following features: ■ Programmable baud-rate generator allowing speeds up to 5 Mbps for regular speed (divide by 16) and 10 Mbps for high speed (divide by 8) ■ Separate 16x8 transmit (TX) and receive (RX) FIFOs to reduce CPU interrupt service loading ■ Programmable FIFO length, including 1-byte deep operation providing conventional double-buffered interface ■ FIFO trigger levels of 1/8, 1/4, 1/2, 3/4, and 7/8 ■ Standard asynchronous communication bits for start, stop, and parity ■ Line-break generation and detection ■ Fully programmable serial interface characteristics – 5, 6, 7, or 8 data bits – Even, odd, stick, or no-parity bit generation/detection – 1 or 2 stop bit generation ■ IrDA serial-IR (SIR) encoder/decoder providing – Programmable use of IrDA Serial Infrared (SIR) or UART input/output – Support of IrDA SIR encoder/decoder functions for data rates up to 115.2 Kbps half-duplex – Support of normal 3/16 and low-power (1.41-2.23 μs) bit durations – Programmable internal clock generator enabling division of reference clock by 1 to 256 for low-power mode bit duration ■ Support for communication with ISO 7816 smart cards ■ Modem flow control (on UART1) ■ EIA-485 9-bit support ■ Standard FIFO-level and End-of-Transmission interrupts ■ Efficient transfers using Micro Direct Memory Access Controller (µDMA) – Separate channels for transmit and receive – Receive single request asserted when data is in the FIFO; burst request asserted at programmed FIFO level June 12, 2014 855 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) – Transmit single request asserted when there is space in the FIFO; burst request asserted at programmed FIFO level 14.1 Block Diagram Figure 14-1. UART Module Block Diagram PIOSC Clock Control UARTCC UARTCTL System Clock DMA Request Baud Clock DMA Control UARTDMACTL Interrupt Interrupt Control TxFIFO 16 x 8 UARTIFLS UARTIM UARTMIS UARTRIS UARTICR Identification Registers . . . UARTPCellID0 Transmitter (with SIR Transmit Encoder) UARTPCellID1 UnTx Baud Rate Generator UARTPCellID2 UARTPCellID3 UARTDR UARTPeriphID0 UARTIBRD UARTFBRD UARTPeriphID1 Receiver (with SIR Receive Decoder) Control/Status UnRx UARTRSR/ECR UARTPeriphID2 UARTFR UARTPeriphID3 RxFIFO 16 x 8 UARTLCRH UARTPeriphID4 UARTCTL UARTPeriphID5 UARTILPR UART9BITADDR UARTPeriphID6 . . . UART9BITAMASK UARTPeriphID7 14.2 UARTPP Signal Description The following table lists the external signals of the UART module and describes the function of each. The UART signals are alternate functions for some GPIO signals and default to be GPIO signals at reset, with the exception of the U0Rx and U0Tx pins which default to the UART function. The column in the table below titled "Pin Mux/Pin Assignment" lists the possible GPIO pin placements for these UART signals. The AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register (page 636) should be set to choose the UART function. The number in parentheses is the encoding that must be programmed into the PMCn field in the GPIO Port Control (GPIOPCTL) register (page 653) to assign the UART signal to the specified GPIO port pin. For more information on configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 614. 856 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 14-1. UART Signals (64LQFP) Pin Name Pin Number Pin Mux / Pin Assignment U0Rx 17 a Pin Type Buffer Type Description PA0 (1) I TTL UART module 0 receive. U0Tx 18 PA1 (1) O TTL UART module 0 transmit. U1CTS 15 29 PC5 (8) PF1 (1) I TTL UART module 1 Clear To Send modem flow control input signal. U1RTS 16 28 PC4 (8) PF0 (1) O TTL UART module 1 Request to Send modem flow control output line. U1Rx 16 45 PC4 (2) PB0 (1) I TTL UART module 1 receive. U1Tx 15 46 PC5 (2) PB1 (1) O TTL UART module 1 transmit. U2Rx 53 PD6 (1) I TTL UART module 2 receive. U2Tx 10 PD7 (1) O TTL UART module 2 transmit. U3Rx 14 PC6 (1) I TTL UART module 3 receive. U3Tx 13 PC7 (1) O TTL UART module 3 transmit. U4Rx 16 PC4 (1) I TTL UART module 4 receive. U4Tx 15 PC5 (1) O TTL UART module 4 transmit. U5Rx 59 PE4 (1) I TTL UART module 5 receive. U5Tx 60 PE5 (1) O TTL UART module 5 transmit. U6Rx 43 PD4 (1) I TTL UART module 6 receive. U6Tx 44 PD5 (1) O TTL UART module 6 transmit. U7Rx 9 PE0 (1) I TTL UART module 7 receive. U7Tx 8 PE1 (1) O TTL UART module 7 transmit. a. The TTL designation indicates the pin has TTL-compatible voltage levels. 14.3 Functional Description Each TM4C1231H6PM UART performs the functions of parallel-to-serial and serial-to-parallel conversions. It is similar in functionality to a 16C550 UART, but is not register compatible. The UART is configured for transmit and/or receive via the TXE and RXE bits of the UART Control (UARTCTL) register (see page 880). Transmit and receive are both enabled out of reset. Before any control registers are programmed, the UART must be disabled by clearing the UARTEN bit in UARTCTL. If the UART is disabled during a TX or RX operation, the current transaction is completed prior to the UART stopping. The UART module also includes a serial IR (SIR) encoder/decoder block that can be connected to an infrared transceiver to implement an IrDA SIR physical layer. The SIR function is programmed using the UARTCTL register. 14.3.1 Transmit/Receive Logic The transmit logic performs parallel-to-serial conversion on the data read from the transmit FIFO. The control logic outputs the serial bit stream beginning with a start bit and followed by the data bits (LSB first), parity bit, and the stop bits according to the programmed configuration in the control registers. See Figure 14-2 on page 858 for details. June 12, 2014 857 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) The receive logic performs serial-to-parallel conversion on the received bit stream after a valid start pulse has been detected. Overrun, parity, frame error checking, and line-break detection are also performed, and their status accompanies the data that is written to the receive FIFO. Figure 14-2. UART Character Frame UnTX LSB 1 5-8 data bits 0 n Parity bit if enabled Start 14.3.2 1-2 stop bits MSB Baud-Rate Generation The baud-rate divisor is a 22-bit number consisting of a 16-bit integer and a 6-bit fractional part. The number formed by these two values is used by the baud-rate generator to determine the bit period. Having a fractional baud-rate divisor allows the UART to generate all the standard baud rates. The 16-bit integer is loaded through the UART Integer Baud-Rate Divisor (UARTIBRD) register (see page 876) and the 6-bit fractional part is loaded with the UART Fractional Baud-Rate Divisor (UARTFBRD) register (see page 877). The baud-rate divisor (BRD) has the following relationship to the system clock (where BRDI is the integer part of the BRD and BRDF is the fractional part, separated by a decimal place.) BRD = BRDI + BRDF = UARTSysClk / (ClkDiv * Baud Rate) where UARTSysClk is the system clock connected to the UART, and ClkDiv is either 16 (if HSE in UARTCTL is clear) or 8 (if HSE is set). By default, this will be the main system clock described in “Clock Control” on page 209. Alternatively, the UART may be clocked from the internal precision oscillator (PIOSC), independent of the system clock selection. This will allow the UART clock to be programmed independently of the system clock PLL settings. See the UARTCC register for more details. The 6-bit fractional number (that is to be loaded into the DIVFRAC bit field in the UARTFBRD register) can be calculated by taking the fractional part of the baud-rate divisor, multiplying it by 64, and adding 0.5 to account for rounding errors: UARTFBRD[DIVFRAC] = integer(BRDF * 64 + 0.5) The UART generates an internal baud-rate reference clock at 8x or 16x the baud-rate (referred to as Baud8 and Baud16, depending on the setting of the HSE bit (bit 5) in UARTCTL). This reference clock is divided by 8 or 16 to generate the transmit clock, and is used for error detection during receive operations. Note that the state of the HSE bit has no effect on clock generation in ISO 7816 smart card mode (when the SMART bit in the UARTCTL register is set). Along with the UART Line Control, High Byte (UARTLCRH) register (see page 878), the UARTIBRD and UARTFBRD registers form an internal 30-bit register. This internal register is only updated when a write operation to UARTLCRH is performed, so any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register for the changes to take effect. To update the baud-rate registers, there are four possible sequences: ■ UARTIBRD write, UARTFBRD write, and UARTLCRH write ■ UARTFBRD write, UARTIBRD write, and UARTLCRH write ■ UARTIBRD write and UARTLCRH write 858 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller ■ UARTFBRD write and UARTLCRH write 14.3.3 Data Transmission Data received or transmitted is stored in two 16-byte FIFOs, though the receive FIFO has an extra four bits per character for status information. For transmission, data is written into the transmit FIFO. If the UART is enabled, it causes a data frame to start transmitting with the parameters indicated in the UARTLCRH register. Data continues to be transmitted until there is no data left in the transmit FIFO. The BUSY bit in the UART Flag (UARTFR) register (see page 873) is asserted as soon as data is written to the transmit FIFO (that is, if the FIFO is non-empty) and remains asserted while data is being transmitted. The BUSY bit is negated only when the transmit FIFO is empty, and the last character has been transmitted from the shift register, including the stop bits. The UART can indicate that it is busy even though the UART may no longer be enabled. When the receiver is idle (the UnRx signal is continuously 1), and the data input goes Low (a start bit has been received), the receive counter begins running and data is sampled on the eighth cycle of Baud16 or fourth cycle of Baud8 depending on the setting of the HSE bit (bit 5) in UARTCTL (described in “Transmit/Receive Logic” on page 857). The start bit is valid and recognized if the UnRx signal is still low on the eighth cycle of Baud16 (HSE clear) or the fourth cycle of Baud 8 (HSE set), otherwise it is ignored. After a valid start bit is detected, successive data bits are sampled on every 16th cycle of Baud16 or 8th cycle of Baud8 (that is, one bit period later) according to the programmed length of the data characters and value of the HSE bit in UARTCTL. The parity bit is then checked if parity mode is enabled. Data length and parity are defined in the UARTLCRH register. Lastly, a valid stop bit is confirmed if the UnRx signal is High, otherwise a framing error has occurred. When a full word is received, the data is stored in the receive FIFO along with any error bits associated with that word. 14.3.4 Serial IR (SIR) The UART peripheral includes an IrDA serial-IR (SIR) encoder/decoder block. The IrDA SIR block provides functionality that converts between an asynchronous UART data stream and a half-duplex serial SIR interface. No analog processing is performed on-chip. The role of the SIR block is to provide a digital encoded output and decoded input to the UART. When enabled, the SIR block uses the UnTx and UnRx pins for the SIR protocol. These signals should be connected to an infrared transceiver to implement an IrDA SIR physical layer link. The SIR block can receive and transmit, but it is only half-duplex so it cannot do both at the same time. Transmission must be stopped before data can be received. The IrDA SIR physical layer specifies a minimum 10-ms delay between transmission and reception. The SIR block has two modes of operation: ■ In normal IrDA mode, a zero logic level is transmitted as a high pulse of 3/16th duration of the selected baud rate bit period on the output pin, while logic one levels are transmitted as a static LOW signal. These levels control the driver of an infrared transmitter, sending a pulse of light for each zero. On the reception side, the incoming light pulses energize the photo transistor base of the receiver, pulling its output LOW and driving the UART input pin LOW. ■ In low-power IrDA mode, the width of the transmitted infrared pulse is set to three times the period of the internally generated IrLPBaud16 signal (1.63 µs, assuming a nominal 1.8432 MHz frequency) by changing the appropriate bit in the UARTCTL register (see page 880). Whether the device is in normal or low-power IrDA mode, a start bit is deemed valid if the decoder is still Low, one period of IrLPBaud16 after the Low was first detected. This enables a normal-mode UART to receive data from a low-power mode UART that can transmit pulses as small as 1.41 µs. June 12, 2014 859 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Thus, for both low-power and normal mode operation, the ILPDVSR field in the UARTILPR register must be programmed such that 1.42 MHz < FIrLPBaud16 < 2.12 MHz, resulting in a low-power pulse duration of 1.41–2.11 μs (three times the period of IrLPBaud16). The minimum frequency of IrLPBaud16 ensures that pulses less than one period of IrLPBaud16 are rejected, but pulses greater than 1.4 μs are accepted as valid pulses. Figure 14-3 on page 860 shows the UART transmit and receive signals, with and without IrDA modulation. Figure 14-3. IrDA Data Modulation Data bits Start bit UnTx 1 0 0 0 1 Stop bit 0 0 1 1 1 UnTx with IrDA 3 16 Bit period Bit period UnRx with IrDA UnRx 0 1 0 Start 1 0 0 1 1 Data bits 0 1 Stop In both normal and low-power IrDA modes: ■ During transmission, the UART data bit is used as the base for encoding ■ During reception, the decoded bits are transferred to the UART receive logic The IrDA SIR physical layer specifies a half-duplex communication link, with a minimum 10-ms delay between transmission and reception. This delay must be generated by software because it is not automatically supported by the UART. The delay is required because the infrared receiver electronics might become biased or even saturated from the optical power coupled from the adjacent transmitter LED. This delay is known as latency or receiver setup time. 14.3.5 ISO 7816 Support The UART offers basic support to allow communication with an ISO 7816 smartcard. When bit 3 (SMART) of the UARTCTL register is set, the UnTx signal is used as a bit clock, and the UnRx signal is used as the half-duplex communication line connected to the smartcard. A GPIO signal can be used to generate the reset signal to the smartcard. The remaining smartcard signals should be provided by the system design. The maximum clock rate in this mode is system clock / 16. When using ISO 7816 mode, the UARTLCRH register must be set to transmit 8-bit words (WLEN bits 6:5 configured to 0x3) with EVEN parity (PEN set and EPS set). In this mode, the UART automatically uses 2 stop bits, and the STP2 bit of the UARTLCRH register is ignored. If a parity error is detected during transmission, UnRx is pulled Low during the second stop bit. In this case, the UART aborts the transmission, flushes the transmit FIFO and discards any data it contains, and raises a parity error interrupt, allowing software to detect the problem and initiate retransmission of the affected data. Note that the UART does not support automatic retransmission in this case. 860 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 14.3.6 Modem Handshake Support This section describes how to configure and use the modem flow control signals for UART1 when connected as a DTE (data terminal equipment) or as a DCE (data communications equipment). In general, a modem is a DCE and a computing device that connects to a modem is the DTE. 14.3.6.1 Signaling The status signals provided by UART1 differ based on whether the UART is used as a DTE or DCE. When used as a DTE, the modem flow control signals are defined as: ■ U1CTS is Clear To Send ■ U1RTS is Request To Send When used as a DCE, the modem flow control signals are defined as: ■ U1CTS is Request To Send ■ U1RTS is Clear To Send 14.3.6.2 Flow Control Flow control can be accomplished by either hardware or software. The following sections describe the different methods. Hardware Flow Control (RTS/CTS) Hardware flow control between two devices is accomplished by connecting the U1RTS output to the Clear-To-Send input on the receiving device, and connecting the Request-To-Send output on the receiving device to the U1CTS input. The U1CTS input controls the transmitter. The transmitter may only transmit data when the U1CTS input is asserted. The U1RTS output signal indicates the state of the receive FIFO. U1CTS remains asserted until the preprogrammed watermark level is reached, indicating that the Receive FIFO has no space to store additional characters. The UARTCTL register bits 15 (CTSEN) and 14 (RTSEN) specify the flow control mode as shown in Table 14-2 on page 861. Table 14-2. Flow Control Mode Description CTSEN RTSEN 1 1 RTS and CTS flow control enabled 1 0 Only CTS flow control enabled 0 1 Only RTS flow control enabled 0 0 Both RTS and CTS flow control disabled Note that when RTSEN is 1, software cannot modify the U1RTS output value through the UARTCTL register Request to Send (RTS) bit, and the status of the RTS bit should be ignored. Software Flow Control (Modem Status Interrupts) Software flow control between two devices is accomplished by using interrupts to indicate the status of the UART. Interrupts may be generated for the U1CTS signal using bit 3 of the UARTIM register. The raw and masked interrupt status may be checked using the UARTRIS and UARTMIS register. These interrupts may be cleared using the UARTICR register. June 12, 2014 861 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) 14.3.7 9-Bit UART Mode The UART provides a 9-bit mode that is enabled with the 9BITEN bit in the UART9BITADDR register. This feature is useful in a multi-drop configuration of the UART where a single master connected to multiple slaves can communicate with a particular slave through its address or set of addresses along with a qualifier for an address byte. All the slaves check for the address qualifier in the place of the parity bit and, if set, then compare the byte received with the preprogrammed address. If the address matches, then it receives or sends further data. If the address does not match, it drops the address byte and any subsequent data bytes. If the UART is in 9-bit mode, then the receiver operates with no parity mode. The address can be predefined to match with the received byte and it can be configured with the UART9BITADDR register. The matching can be extended to a set of addresses using the address mask in the UART9BITAMASK register. By default, the UART9BITAMASK is 0xFF, meaning that only the specified address is matched. When not finding a match, the rest of the data bytes with the 9th bit cleared are dropped. If a match is found, then an interrupt is generated to the NVIC for further action. The subsequent data bytes with the cleared 9th bit are stored in the FIFO. Software can mask this interrupt in case μDMA and/or FIFO operations are enabled for this instance and processor intervention is not required. All the send transactions with 9-bit mode are data bytes and the 9th bit is cleared. Software can override the 9th bit to be set (to indicate address) by overriding the parity settings to sticky parity with odd parity enabled for a particular byte. To match the transmission time with correct parity settings, the address byte can be transmitted as a single then a burst transfer. The Transmit FIFO does not hold the address/data bit, hence software should take care of enabling the address bit appropriately. 14.3.8 FIFO Operation The UART has two 16x8 FIFOs; one for transmit and one for receive. Both FIFOs are accessed via the UART Data (UARTDR) register (see page 868). Read operations of the UARTDR register return a 12-bit value consisting of 8 data bits and 4 error flags while write operations place 8-bit data in the transmit FIFO. Out of reset, both FIFOs are disabled and act as 1-byte-deep holding registers. The FIFOs are enabled by setting the FEN bit in UARTLCRH (page 878). FIFO status can be monitored via the UART Flag (UARTFR) register (see page 873) and the UART Receive Status (UARTRSR) register. Hardware monitors empty, full and overrun conditions. The UARTFR register contains empty and full flags (TXFE, TXFF, RXFE, and RXFF bits), and the UARTRSR register shows overrun status via the OE bit. If the FIFOs are disabled, the empty and full flags are set according to the status of the 1-byte-deep holding registers. The trigger points at which the FIFOs generate interrupts is controlled via the UART Interrupt FIFO Level Select (UARTIFLS) register (see page 884). Both FIFOs can be individually configured to trigger interrupts at different levels. Available configurations include ⅛, ¼, ½, ¾, and ⅞. For example, if the ¼ option is selected for the receive FIFO, the UART generates a receive interrupt after 4 data bytes are received. Out of reset, both FIFOs are configured to trigger an interrupt at the ½ mark. 14.3.9 Interrupts The UART can generate interrupts when the following conditions are observed: ■ Overrun Error ■ Break Error ■ Parity Error 862 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller ■ Framing Error ■ Receive Timeout ■ Transmit (when condition defined in the TXIFLSEL bit in the UARTIFLS register is met, or if the EOT bit in UARTCTL is set, when the last bit of all transmitted data leaves the serializer) ■ Receive (when condition defined in the RXIFLSEL bit in the UARTIFLS register is met) All of the interrupt events are ORed together before being sent to the interrupt controller, so the UART can only generate a single interrupt request to the controller at any given time. Software can service multiple interrupt events in a single interrupt service routine by reading the UART Masked Interrupt Status (UARTMIS) register (see page 892). The interrupt events that can trigger a controller-level interrupt are defined in the UART Interrupt Mask (UARTIM) register (see page 886) by setting the corresponding IM bits. If interrupts are not used, the raw interrupt status is visible via the UART Raw Interrupt Status (UARTRIS) register (see page 889). Note: For receive timeout, the RTIM bit in the UARTIM register must be set to see the RTMIS and RTRIS status in the UARTMIS and UARTRIS registers. Interrupts are always cleared (for both the UARTMIS and UARTRIS registers) by writing a 1 to the corresponding bit in the UART Interrupt Clear (UARTICR) register (see page 895). The receive timeout interrupt is asserted when the receive FIFO is not empty, and no further data is received over a 32-bit period when the HSE bit is clear or over a 64-bit period when the HSE bit is set. The receive timeout interrupt is cleared either when the FIFO becomes empty through reading all the data (or by reading the holding register), or when a 1 is written to the corresponding bit in the UARTICR register. The receive interrupt changes state when one of the following events occurs: ■ If the FIFOs are enabled and the receive FIFO reaches the programmed trigger level, the RXRIS bit is set. The receive interrupt is cleared by reading data from the receive FIFO until it becomes less than the trigger level, or by clearing the interrupt by writing a 1 to the RXIC bit. ■ If the FIFOs are disabled (have a depth of one location) and data is received thereby filling the location, the RXRIS bit is set. The receive interrupt is cleared by performing a single read of the receive FIFO, or by clearing the interrupt by writing a 1 to the RXIC bit. The transmit interrupt changes state when one of the following events occurs: ■ If the FIFOs are enabled and the transmit FIFO progresses through the programmed trigger level, the TXRIS bit is set. The transmit interrupt is based on a transition through level, therefore the FIFO must be written past the programmed trigger level otherwise no further transmit interrupts will be generated. The transmit interrupt is cleared by writing data to the transmit FIFO until it becomes greater than the trigger level, or by clearing the interrupt by writing a 1 to the TXIC bit. ■ If the FIFOs are disabled (have a depth of one location) and there is no data present in the transmitters single location, the TXRIS bit is set. It is cleared by performing a single write to the transmit FIFO, or by clearing the interrupt by writing a 1 to the TXIC bit. 14.3.10 Loopback Operation The UART can be placed into an internal loopback mode for diagnostic or debug work by setting the LBE bit in the UARTCTL register (see page 880). In loopback mode, data transmitted on the June 12, 2014 863 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) UnTx output is received on the UnRx input. Note that the LBE bit should be set before the UART is enabled. 14.3.11 DMA Operation The UART provides an interface to the μDMA controller with separate channels for transmit and receive. The DMA operation of the UART is enabled through the UART DMA Control (UARTDMACTL) register. When DMA operation is enabled, the UART asserts a DMA request on the receive or transmit channel when the associated FIFO can transfer data. For the receive channel, a single transfer request is asserted whenever any data is in the receive FIFO. A burst transfer request is asserted whenever the amount of data in the receive FIFO is at or above the FIFO trigger level configured in the UARTIFLS register. For the transmit channel, a single transfer request is asserted whenever there is at least one empty location in the transmit FIFO. The burst request is asserted whenever the transmit FIFO contains fewer characters than the FIFO trigger level. The single and burst DMA transfer requests are handled automatically by the μDMA controller depending on how the DMA channel is configured. To enable DMA operation for the receive channel, set the RXDMAE bit of the DMA Control (UARTDMACTL) register. To enable DMA operation for the transmit channel, set the TXDMAE bit of the UARTDMACTL register. The UART can also be configured to stop using DMA for the receive channel if a receive error occurs. If the DMAERR bit of the UARTDMACR register is set and a receive error occurs, the DMA receive requests are automatically disabled. This error condition can be cleared by clearing the appropriate UART error interrupt. If the µDMA is enabled, then the controller triggers an interrupt when the TX FIFO or RX FIFO has reached a trigger point as programmed in the UARTIFLS register. The interrupt occurs on the UART interrupt vector. Therefore, if interrupts are used for UART operation and DMA is enabled, the UART interrupt handler must be designed to handle the μDMA completion interrupt. Note: To trigger an interrupt on transmit completion from the UART's serializer, the EOT bit must be set in the UARTCTL register. In this configuration, the transmit interrupt is generated once the FIFO is completely empty and all data including the stop bits have left the transmit serializer. In this case, setting the TXIFLSEL bit in the UARTIFLS register is ignored. When transfers are performed from a FIFO of the UART using the μDMA, and any interrupt is generated from the UART, the UART module's status bit in the DMA Channel Interrupt Status (DMACHIS) register must be checked at the end of the interrupt service routine. If the status bit is set, clear the interrupt by writing a 1 to it. See “Micro Direct Memory Access (μDMA)” on page 550 for more details about programming the μDMA controller. 14.4 Initialization and Configuration To enable and initialize the UART, the following steps are necessary: 1. Enable the UART module using the RCGCUART register (see page 325). 2. Enable the clock to the appropriate GPIO module via the RCGCGPIO register (see page 321). To find out which GPIO port to enable, refer to Table 20-5 on page 1091. 3. Set the GPIO AFSEL bits for the appropriate pins (see page 636). To determine which GPIOs to configure, see Table 20-4 on page 1087. 4. Configure the GPIO current level and/or slew rate as specified for the mode selected (see page 638 and page 646). 864 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 5. Configure the PMCn fields in the GPIOPCTL register to assign the UART signals to the appropriate pins (see page 653 and Table 20-5 on page 1091). To use the UART, the peripheral clock must be enabled by setting the appropriate bit in the RCGCUART register (page 325). In addition, the clock to the appropriate GPIO module must be enabled via the RCGCGPIO register (page 321) in the System Control module. To find out which GPIO port to enable, refer to Table 20-5 on page 1091. This section discusses the steps that are required to use a UART module. For this example, the UART clock is assumed to be 20 MHz, and the desired UART configuration is: ■ 115200 baud rate ■ Data length of 8 bits ■ One stop bit ■ No parity ■ FIFOs disabled ■ No interrupts The first thing to consider when programming the UART is the baud-rate divisor (BRD), because the UARTIBRD and UARTFBRD registers must be written before the UARTLCRH register. Using the equation described in “Baud-Rate Generation” on page 858, the BRD can be calculated: BRD = 20,000,000 / (16 * 115,200) = 10.8507 which means that the DIVINT field of the UARTIBRD register (see page 876) should be set to 10 decimal or 0xA. The value to be loaded into the UARTFBRD register (see page 877) is calculated by the equation: UARTFBRD[DIVFRAC] = integer(0.8507 * 64 + 0.5) = 54 With the BRD values in hand, the UART configuration is written to the module in the following order: 1. Disable the UART by clearing the UARTEN bit in the UARTCTL register. 2. Write the integer portion of the BRD to the UARTIBRD register. 3. Write the fractional portion of the BRD to the UARTFBRD register. 4. Write the desired serial parameters to the UARTLCRH register (in this case, a value of 0x0000.0060). 5. Configure the UART clock source by writing to the UARTCC register. 6. Optionally, configure the µDMA channel (see “Micro Direct Memory Access (μDMA)” on page 550) and enable the DMA option(s) in the UARTDMACTL register. 7. Enable the UART by setting the UARTEN bit in the UARTCTL register. 14.5 Register Map Table 14-3 on page 866 lists the UART registers. The offset listed is a hexadecimal increment to the register's address, relative to that UART's base address: June 12, 2014 865 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) ■ ■ ■ ■ ■ ■ ■ ■ UART0: 0x4000.C000 UART1: 0x4000.D000 UART2: 0x4000.E000 UART3: 0x4000.F000 UART4: 0x4001.0000 UART5: 0x4001.1000 UART6: 0x4001.2000 UART7: 0x4001.3000 The UART module clock must be enabled before the registers can be programmed (see page 325). There must be a delay of 3 system clocks after the UART module clock is enabled before any UART module registers are accessed. The UART must be disabled (see the UARTEN bit in the UARTCTL register on page 880) before any of the control registers are reprogrammed. When the UART is disabled during a TX or RX operation, the current transaction is completed prior to the UART stopping. Table 14-3. UART Register Map Type Reset Description See page UARTDR RW 0x0000.0000 UART Data 868 0x004 UARTRSR/UARTECR RW 0x0000.0000 UART Receive Status/Error Clear 870 0x018 UARTFR RO 0x0000.0090 UART Flag 873 0x020 UARTILPR RW 0x0000.0000 UART IrDA Low-Power Register 875 0x024 UARTIBRD RW 0x0000.0000 UART Integer Baud-Rate Divisor 876 0x028 UARTFBRD RW 0x0000.0000 UART Fractional Baud-Rate Divisor 877 0x02C UARTLCRH RW 0x0000.0000 UART Line Control 878 0x030 UARTCTL RW 0x0000.0300 UART Control 880 0x034 UARTIFLS RW 0x0000.0012 UART Interrupt FIFO Level Select 884 0x038 UARTIM RW 0x0000.0000 UART Interrupt Mask 886 0x03C UARTRIS RO 0x0000.0000 UART Raw Interrupt Status 889 0x040 UARTMIS RO 0x0000.0000 UART Masked Interrupt Status 892 0x044 UARTICR W1C 0x0000.0000 UART Interrupt Clear 895 0x048 UARTDMACTL RW 0x0000.0000 UART DMA Control 897 0x0A4 UART9BITADDR RW 0x0000.0000 UART 9-Bit Self Address 898 0x0A8 UART9BITAMASK RW 0x0000.00FF UART 9-Bit Self Address Mask 899 0xFC0 UARTPP RO 0x0000.0003 UART Peripheral Properties 900 0xFC8 UARTCC RW 0x0000.0000 UART Clock Configuration 901 0xFD0 UARTPeriphID4 RO 0x0000.0000 UART Peripheral Identification 4 902 0xFD4 UARTPeriphID5 RO 0x0000.0000 UART Peripheral Identification 5 903 0xFD8 UARTPeriphID6 RO 0x0000.0000 UART Peripheral Identification 6 904 Offset Name 0x000 866 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 14-3. UART Register Map (continued) Offset Name 0xFDC Reset UARTPeriphID7 RO 0x0000.0000 UART Peripheral Identification 7 905 0xFE0 UARTPeriphID0 RO 0x0000.0060 UART Peripheral Identification 0 906 0xFE4 UARTPeriphID1 RO 0x0000.0000 UART Peripheral Identification 1 907 0xFE8 UARTPeriphID2 RO 0x0000.0018 UART Peripheral Identification 2 908 0xFEC UARTPeriphID3 RO 0x0000.0001 UART Peripheral Identification 3 909 0xFF0 UARTPCellID0 RO 0x0000.000D UART PrimeCell Identification 0 910 0xFF4 UARTPCellID1 RO 0x0000.00F0 UART PrimeCell Identification 1 911 0xFF8 UARTPCellID2 RO 0x0000.0005 UART PrimeCell Identification 2 912 0xFFC UARTPCellID3 RO 0x0000.00B1 UART PrimeCell Identification 3 913 14.6 Description See page Type Register Descriptions The remainder of this section lists and describes the UART registers, in numerical order by address offset. June 12, 2014 867 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 1: UART Data (UARTDR), offset 0x000 Important: This register is read-sensitive. See the register description for details. This register is the data register (the interface to the FIFOs). For transmitted data, if the FIFO is enabled, data written to this location is pushed onto the transmit FIFO. If the FIFO is disabled, data is stored in the transmitter holding register (the bottom word of the transmit FIFO). A write to this register initiates a transmission from the UART. For received data, if the FIFO is enabled, the data byte and the 4-bit status (break, frame, parity, and overrun) is pushed onto the 12-bit wide receive FIFO. If the FIFO is disabled, the data byte and status are stored in the receiving holding register (the bottom word of the receive FIFO). The received data can be retrieved by reading this register. UART Data (UARTDR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x000 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 15 14 13 12 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 11 10 9 8 OE BE PE FE RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:12 reserved RO 0x0000.0 11 OE RO 0 DATA RW 0 RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Overrun Error Value Description 0 No data has been lost due to a FIFO overrun. 1 New data was received when the FIFO was full, resulting in data loss. 868 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 10 BE RO 0 Description UART Break Error Value Description 0 No break condition has occurred 1 A break condition has been detected, indicating that the receive data input was held Low for longer than a full-word transmission time (defined as start, data, parity, and stop bits). In FIFO mode, this error is associated with the character at the top of the FIFO. When a break occurs, only one 0 character is loaded into the FIFO. The next character is only enabled after the received data input goes to a 1 (marking state), and the next valid start bit is received. 9 PE RO 0 UART Parity Error Value Description 0 No parity error has occurred 1 The parity of the received data character does not match the parity defined by bits 2 and 7 of the UARTLCRH register. In FIFO mode, this error is associated with the character at the top of the FIFO. 8 FE RO 0 UART Framing Error Value Description 7:0 DATA RW 0x00 0 No framing error has occurred 1 The received character does not have a valid stop bit (a valid stop bit is 1). Data Transmitted or Received Data that is to be transmitted via the UART is written to this field. When read, this field contains the data that was received by the UART. June 12, 2014 869 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 2: UART Receive Status/Error Clear (UARTRSR/UARTECR), offset 0x004 The UARTRSR/UARTECR register is the receive status register/error clear register. In addition to the UARTDR register, receive status can also be read from the UARTRSR register. If the status is read from this register, then the status information corresponds to the entry read from UARTDR prior to reading UARTRSR. The status information for overrun is set immediately when an overrun condition occurs. The UARTRSR register cannot be written. A write of any value to the UARTECR register clears the framing, parity, break, and overrun errors. All the bits are cleared on reset. Read-Only Status Register UART Receive Status/Error Clear (UARTRSR/UARTECR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x004 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 OE BE PE FE RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3 OE RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Overrun Error Value Description 0 No data has been lost due to a FIFO overrun. 1 New data was received when the FIFO was full, resulting in data loss. This bit is cleared by a write to UARTECR. The FIFO contents remain valid because no further data is written when the FIFO is full, only the contents of the shift register are overwritten. The CPU must read the data in order to empty the FIFO. 870 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 2 BE RO 0 Description UART Break Error Value Description 0 No break condition has occurred 1 A break condition has been detected, indicating that the receive data input was held Low for longer than a full-word transmission time (defined as start, data, parity, and stop bits). This bit is cleared to 0 by a write to UARTECR. In FIFO mode, this error is associated with the character at the top of the FIFO. When a break occurs, only one 0 character is loaded into the FIFO. The next character is only enabled after the receive data input goes to a 1 (marking state) and the next valid start bit is received. 1 PE RO 0 UART Parity Error Value Description 0 No parity error has occurred 1 The parity of the received data character does not match the parity defined by bits 2 and 7 of the UARTLCRH register. This bit is cleared to 0 by a write to UARTECR. 0 FE RO 0 UART Framing Error Value Description 0 No framing error has occurred 1 The received character does not have a valid stop bit (a valid stop bit is 1). This bit is cleared to 0 by a write to UARTECR. In FIFO mode, this error is associated with the character at the top of the FIFO. Write-Only Error Clear Register UART Receive Status/Error Clear (UARTRSR/UARTECR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x004 Type WO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 WO 0 WO 0 WO 0 WO 0 3 2 1 0 WO 0 WO 0 WO 0 WO 0 reserved Type Reset WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset WO 0 WO 0 WO 0 WO 0 WO 0 DATA WO 0 WO 0 WO 0 WO 0 WO 0 June 12, 2014 WO 0 WO 0 871 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 31:8 reserved WO 0x0000.00 7:0 DATA WO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Error Clear A write to this register of any data clears the framing, parity, break, and overrun flags. 872 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 3: UART Flag (UARTFR), offset 0x018 The UARTFR register is the flag register. After reset, the TXFF, RXFF, and BUSY bits are 0, and TXFE and RXFE bits are 1. The CTS bit indicate the modem flow control. Note that the modem bits are only implemented on UART1 and are reserved on UART0 and UART2. UART Flag (UARTFR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x018 Type RO, reset 0x0000.0090 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 2 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 TXFE RO 1 RO 0 RO 0 7 6 5 4 3 TXFE RXFF TXFF RXFE BUSY RO 1 RO 0 RO 0 RO 1 RO 0 reserved RO 0 RO 0 0 CTS RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Transmit FIFO Empty The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. Value Description 0 The transmitter has data to transmit. 1 If the FIFO is disabled (FEN is 0), the transmit holding register is empty. If the FIFO is enabled (FEN is 1), the transmit FIFO is empty. 6 RXFF RO 0 UART Receive FIFO Full The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. Value Description 0 The receiver can receive data. 1 If the FIFO is disabled (FEN is 0), the receive holding register is full. If the FIFO is enabled (FEN is 1), the receive FIFO is full. June 12, 2014 873 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 5 TXFF RO 0 Description UART Transmit FIFO Full The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. Value Description 0 The transmitter is not full. 1 If the FIFO is disabled (FEN is 0), the transmit holding register is full. If the FIFO is enabled (FEN is 1), the transmit FIFO is full. 4 RXFE RO 1 UART Receive FIFO Empty The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. Value Description 0 The receiver is not empty. 1 If the FIFO is disabled (FEN is 0), the receive holding register is empty. If the FIFO is enabled (FEN is 1), the receive FIFO is empty. 3 BUSY RO 0 UART Busy Value Description 0 The UART is not busy. 1 The UART is busy transmitting data. This bit remains set until the complete byte, including all stop bits, has been sent from the shift register. This bit is set as soon as the transmit FIFO becomes non-empty (regardless of whether UART is enabled). 2:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 CTS RO 0 Clear To Send Value Description 0 The U1CTS signal is not asserted. 1 The U1CTS signal is asserted. 874 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 4: UART IrDA Low-Power Register (UARTILPR), offset 0x020 The UARTILPR register stores the 8-bit low-power counter divisor value used to derive the low-power SIR pulse width clock by dividing down the system clock (SysClk). All the bits are cleared when reset. The internal IrLPBaud16 clock is generated by dividing down SysClk according to the low-power divisor value written to UARTILPR. The duration of SIR pulses generated when low-power mode is enabled is three times the period of the IrLPBaud16 clock. The low-power divisor value is calculated as follows: ILPDVSR = SysClk / FIrLPBaud16 where FIrLPBaud16 is nominally 1.8432 MHz. Because the IrLPBaud16 clock is used to sample transmitted data irrespective of mode, the ILPDVSR field must be programmed in both low power and normal mode,such that 1.42 MHz < FIrLPBaud16 < 2.12 MHz, resulting in a low-power pulse duration of 1.41–2.11 μs (three times the period of IrLPBaud16). The minimum frequency of IrLPBaud16 ensures that pulses less than one period of IrLPBaud16 are rejected, but pulses greater than 1.4 μs are accepted as valid pulses. Note: Zero is an illegal value. Programming a zero value results in no IrLPBaud16 pulses being generated. UART IrDA Low-Power Register (UARTILPR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x020 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset ILPDVSR RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 ILPDVSR RW 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. IrDA Low-Power Divisor This field contains the 8-bit low-power divisor value. June 12, 2014 875 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 5: UART Integer Baud-Rate Divisor (UARTIBRD), offset 0x024 The UARTIBRD register is the integer part of the baud-rate divisor value. All the bits are cleared on reset. The minimum possible divide ratio is 1 (when UARTIBRD=0), in which case the UARTFBRD register is ignored. When changing the UARTIBRD register, the new value does not take effect until transmission/reception of the current character is complete. Any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register. See “Baud-Rate Generation” on page 858 for configuration details. UART Integer Baud-Rate Divisor (UARTIBRD) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x024 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 DIVINT Type Reset RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 DIVINT RW 0x0000 Integer Baud-Rate Divisor 876 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 6: UART Fractional Baud-Rate Divisor (UARTFBRD), offset 0x028 The UARTFBRD register is the fractional part of the baud-rate divisor value. All the bits are cleared on reset. When changing the UARTFBRD register, the new value does not take effect until transmission/reception of the current character is complete. Any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register. See “Baud-Rate Generation” on page 858 for configuration details. UART Fractional Baud-Rate Divisor (UARTFBRD) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x028 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 DIVFRAC RO 0 Bit/Field Name Type Reset 31:6 reserved RO 0x0000.000 5:0 DIVFRAC RW 0x0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Fractional Baud-Rate Divisor June 12, 2014 877 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 7: UART Line Control (UARTLCRH), offset 0x02C The UARTLCRH register is the line control register. Serial parameters such as data length, parity, and stop bit selection are implemented in this register. When updating the baud-rate divisor (UARTIBRD and/or UARTIFRD), the UARTLCRH register must also be written. The write strobe for the baud-rate divisor registers is tied to the UARTLCRH register. UART Line Control (UARTLCRH) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x02C Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 FEN STP2 EPS PEN BRK RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset SPS RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 SPS RW 0 RW 0 WLEN RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Stick Parity Select When bits 1, 2, and 7 of UARTLCRH are set, the parity bit is transmitted and checked as a 0. When bits 1 and 7 are set and 2 is cleared, the parity bit is transmitted and checked as a 1. When this bit is cleared, stick parity is disabled. 6:5 WLEN RW 0x0 UART Word Length The bits indicate the number of data bits transmitted or received in a frame as follows: Value Description 0x0 5 bits (default) 0x1 6 bits 0x2 7 bits 0x3 8 bits 878 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 4 FEN RW 0 Description UART Enable FIFOs Value Description 3 STP2 RW 0 0 The FIFOs are disabled (Character mode). The FIFOs become 1-byte-deep holding registers. 1 The transmit and receive FIFO buffers are enabled (FIFO mode). UART Two Stop Bits Select Value Description 0 One stop bit is transmitted at the end of a frame. 1 Two stop bits are transmitted at the end of a frame. The receive logic does not check for two stop bits being received. When in 7816 smartcard mode (the SMART bit is set in the UARTCTL register), the number of stop bits is forced to 2. 2 EPS RW 0 UART Even Parity Select Value Description 0 Odd parity is performed, which checks for an odd number of 1s. 1 Even parity generation and checking is performed during transmission and reception, which checks for an even number of 1s in data and parity bits. This bit has no effect when parity is disabled by the PEN bit. 1 PEN RW 0 UART Parity Enable Value Description 0 BRK RW 0 0 Parity is disabled and no parity bit is added to the data frame. 1 Parity checking and generation is enabled. UART Send Break Value Description 0 Normal use. 1 A Low level is continually output on the UnTx signal, after completing transmission of the current character. For the proper execution of the break command, software must set this bit for at least two frames (character periods). June 12, 2014 879 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 8: UART Control (UARTCTL), offset 0x030 The UARTCTL register is the control register. All the bits are cleared on reset except for the Transmit Enable (TXE) and Receive Enable (RXE) bits, which are set. To enable the UART module, the UARTEN bit must be set. If software requires a configuration change in the module, the UARTEN bit must be cleared before the configuration changes are written. If the UART is disabled during a transmit or receive operation, the current transaction is completed prior to the UART stopping. Note: The UARTCTL register should not be changed while the UART is enabled or else the results are unpredictable. The following sequence is recommended for making changes to the UARTCTL register. 1. Disable the UART. 2. Wait for the end of transmission or reception of the current character. 3. Flush the transmit FIFO by clearing bit 4 (FEN) in the line control register (UARTLCRH). 4. Reprogram the control register. 5. Enable the UART. UART Control (UARTCTL) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x030 Type RW, reset 0x0000.0300 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 Type Reset RO 0 RO 0 RO 0 13 12 15 14 CTSEN RTSEN RW 0 RW 0 reserved RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 11 10 9 8 7 6 5 4 3 2 1 0 RTS reserved RXE TXE LBE reserved HSE EOT SMART SIRLP SIREN UARTEN RW 0 RO 0 RW 1 RW 1 RW 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 CTSEN RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Enable Clear To Send Value Description 0 CTS hardware flow control is disabled. 1 CTS hardware flow control is enabled. Data is only transmitted when the U1CTS signal is asserted. 880 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 14 RTSEN RW 0 Description Enable Request to Send Value Description 0 RTS hardware flow control is disabled. 1 RTS hardware flow control is enabled. Data is only requested (by asserting U1RTS) when the receive FIFO has available entries. 13:12 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 11 RTS RW 0 Request to Send When RTSEN is clear, the status of this bit is reflected on the U1RTS signal. If RTSEN is set, this bit is ignored on a write and should be ignored on read. 10 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9 RXE RW 1 UART Receive Enable Value Description 0 The receive section of the UART is disabled. 1 The receive section of the UART is enabled. If the UART is disabled in the middle of a receive, it completes the current character before stopping. Note: 8 TXE RW 1 To enable reception, the UARTEN bit must also be set. UART Transmit Enable Value Description 0 The transmit section of the UART is disabled. 1 The transmit section of the UART is enabled. If the UART is disabled in the middle of a transmission, it completes the current character before stopping. Note: 7 LBE RW 0 To enable transmission, the UARTEN bit must also be set. UART Loop Back Enable Value Description 6 reserved RO 0 0 Normal operation. 1 The UnTx path is fed through the UnRx path. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 12, 2014 881 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 5 HSE RW 0 Description High-Speed Enable Value Description 0 The UART is clocked using the system clock divided by 16. 1 The UART is clocked using the system clock divided by 8. Note: System clock used is also dependent on the baud-rate divisor configuration (see page 876) and page 877). The state of this bit has no effect on clock generation in ISO 7816 smart card mode (the SMART bit is set). 4 EOT RW 0 End of Transmission This bit determines the behavior of the TXRIS bit in the UARTRIS register. Value Description 3 SMART RW 0 0 The TXRIS bit is set when the transmit FIFO condition specified in UARTIFLS is met. 1 The TXRIS bit is set only after all transmitted data, including stop bits, have cleared the serializer. ISO 7816 Smart Card Support Value Description 0 Normal operation. 1 The UART operates in Smart Card mode. The application must ensure that it sets 8-bit word length (WLEN set to 0x3) and even parity (PEN set to 1, EPS set to 1, SPS set to 0) in UARTLCRH when using ISO 7816 mode. In this mode, the value of the STP2 bit in UARTLCRH is ignored and the number of stop bits is forced to 2. Note that the UART does not support automatic retransmission on parity errors. If a parity error is detected on transmission, all further transmit operations are aborted and software must handle retransmission of the affected byte or message. 2 SIRLP RW 0 UART SIR Low-Power Mode This bit selects the IrDA encoding mode. Value Description 0 Low-level bits are transmitted as an active High pulse with a width of 3/16th of the bit period. 1 The UART operates in SIR Low-Power mode. Low-level bits are transmitted with a pulse width which is 3 times the period of the IrLPBaud16 input signal, regardless of the selected bit rate. Setting this bit uses less power, but might reduce transmission distances. See page 875 for more information. 882 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 1 SIREN RW 0 Description UART SIR Enable Value Description 0 UARTEN RW 0 0 Normal operation. 1 The IrDA SIR block is enabled, and the UART will transmit and receive data using SIR protocol. UART Enable Value Description 0 The UART is disabled. 1 The UART is enabled. If the UART is disabled in the middle of transmission or reception, it completes the current character before stopping. June 12, 2014 883 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 9: UART Interrupt FIFO Level Select (UARTIFLS), offset 0x034 The UARTIFLS register is the interrupt FIFO level select register. You can use this register to define the FIFO level at which the TXRIS and RXRIS bits in the UARTRIS register are triggered. The interrupts are generated based on a transition through a level rather than being based on the level. That is, the interrupts are generated when the fill level progresses through the trigger level. For example, if the receive trigger level is set to the half-way mark, the interrupt is triggered as the module is receiving the 9th character. Out of reset, the TXIFLSEL and RXIFLSEL bits are configured so that the FIFOs trigger an interrupt at the half-way mark. UART Interrupt FIFO Level Select (UARTIFLS) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x034 Type RW, reset 0x0000.0012 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 4 3 2 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RXIFLSEL RO 0 Bit/Field Name Type Reset 31:6 reserved RO 0x0000.00 5:3 RXIFLSEL RW 0x2 RO 0 RO 0 RO 0 RW 0 RW 1 TXIFLSEL RW 0 RW 0 RW 1 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Receive Interrupt FIFO Level Select The trigger points for the receive interrupt are as follows: Value Description 0x0 RX FIFO ≥ ⅛ full 0x1 RX FIFO ≥ ¼ full 0x2 RX FIFO ≥ ½ full (default) 0x3 RX FIFO ≥ ¾ full 0x4 RX FIFO ≥ ⅞ full 0x5-0x7 Reserved 884 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 2:0 TXIFLSEL RW 0x2 Description UART Transmit Interrupt FIFO Level Select The trigger points for the transmit interrupt are as follows: Value Description 0x0 TX FIFO ≤ ⅞ empty 0x1 TX FIFO ≤ ¾ empty 0x2 TX FIFO ≤ ½ empty (default) 0x3 TX FIFO ≤ ¼ empty 0x4 TX FIFO ≤ ⅛ empty 0x5-0x7 Reserved Note: If the EOT bit in UARTCTL is set (see page 880), the transmit interrupt is generated once the FIFO is completely empty and all data including stop bits have left the transmit serializer. In this case, the setting of TXIFLSEL is ignored. June 12, 2014 885 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 10: UART Interrupt Mask (UARTIM), offset 0x038 The UARTIM register is the interrupt mask set/clear register. On a read, this register gives the current value of the mask on the relevant interrupt. Setting a bit allows the corresponding raw interrupt signal to be routed to the interrupt controller. Clearing a bit prevents the raw interrupt signal from being sent to the interrupt controller. UART Interrupt Mask (UARTIM) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x038 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 9BITIM reserved OEIM RW 0 RO 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 BEIM PEIM FEIM RTIM TXIM RXIM CTSIM reserved RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RO 0 reserved Type Reset reserved Type Reset RO 0 RO 0 RO 0 reserved RO 0 RO 0 Bit/Field Name Type Reset Description 31:13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 9BITIM RW 0 9-Bit Mode Interrupt Mask Value Description 0 The 9BITRIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the 9BITRIS bit in the UARTRIS register is set. 11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 OEIM RW 0 UART Overrun Error Interrupt Mask Value Description 0 The OERIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the OERIS bit in the UARTRIS register is set. 886 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 9 BEIM RW 0 Description UART Break Error Interrupt Mask Value Description 8 PEIM RW 0 0 The BERIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the BERIS bit in the UARTRIS register is set. UART Parity Error Interrupt Mask Value Description 7 FEIM RW 0 0 The PERIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the PERIS bit in the UARTRIS register is set. UART Framing Error Interrupt Mask Value Description 6 RTIM RW 0 0 The FERIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the FERIS bit in the UARTRIS register is set. UART Receive Time-Out Interrupt Mask Value Description 5 TXIM RW 0 0 The RTRIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the RTRIS bit in the UARTRIS register is set. UART Transmit Interrupt Mask Value Description 4 RXIM RW 0 0 The TXRIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the TXRIS bit in the UARTRIS register is set. UART Receive Interrupt Mask Value Description 0 The RXRIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the RXRIS bit in the UARTRIS register is set. June 12, 2014 887 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset Description 3:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CTSIM RW 0 UART Clear to Send Modem Interrupt Mask Value Description 0 The CTSRIS interrupt is suppressed and not sent to the interrupt controller. 1 An interrupt is sent to the interrupt controller when the CTSRIS bit in the UARTRIS register is set. This bit is implemented only on UART1 and is reserved for UART0 and UART2. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 888 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 11: UART Raw Interrupt Status (UARTRIS), offset 0x03C The UARTRIS register is the raw interrupt status register. On a read, this register gives the current raw status value of the corresponding interrupt. A write has no effect. UART Raw Interrupt Status (UARTRIS) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x03C Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 reserved Type Reset RO 0 15 RO 0 RO 0 14 13 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 12 11 10 9 8 7 6 5 4 9BITRIS reserved OERIS BERIS PERIS FERIS RTRIS TXRIS RXRIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved RO 0 RO 0 1 0 CTSRIS reserved RO 0 RO 0 Bit/Field Name Type Reset Description 31:13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 9BITRIS RO 0 9-Bit Mode Raw Interrupt Status Value Description 0 No interrupt 1 A receive address match has occurred. This bit is cleared by writing a 1 to the 9BITIC bit in the UARTICR register. 11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 OERIS RO 0 UART Overrun Error Raw Interrupt Status Value Description 0 No interrupt 1 An overrun error has occurred. This bit is cleared by writing a 1 to the OEIC bit in the UARTICR register. 9 BERIS RO 0 UART Break Error Raw Interrupt Status Value Description 0 No interrupt 1 A break error has occurred. This bit is cleared by writing a 1 to the BEIC bit in the UARTICR register. June 12, 2014 889 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 8 PERIS RO 0 Description UART Parity Error Raw Interrupt Status Value Description 0 No interrupt 1 A parity error has occurred. This bit is cleared by writing a 1 to the PEIC bit in the UARTICR register. 7 FERIS RO 0 UART Framing Error Raw Interrupt Status Value Description 0 No interrupt 1 A framing error has occurred. This bit is cleared by writing a 1 to the FEIC bit in the UARTICR register. 6 RTRIS RO 0 UART Receive Time-Out Raw Interrupt Status Value Description 0 No interrupt 1 A receive time out has occurred. This bit is cleared by writing a 1 to the RTIC bit in the UARTICR register. For receive timeout, the RTIM bit in the UARTIM register must be set to see the RTRIS status. 5 TXRIS RO 0 UART Transmit Raw Interrupt Status Value Description 0 No interrupt 1 If the EOT bit in the UARTCTL register is clear, the transmit FIFO level has passed through the condition defined in the UARTIFLS register. If the EOT bit is set, the last bit of all transmitted data and flags has left the serializer. This bit is cleared by writing a 1 to the TXIC bit in the UARTICR register or by writing data to the transmit FIFO until it becomes greater than the trigger level, if the FIFO is enabled, or by writing a single byte if the FIFO is disabled. 4 RXRIS RO 0 UART Receive Raw Interrupt Status Value Description 0 No interrupt 1 The receive FIFO level has passed through the condition defined in the UARTIFLS register. This bit is cleared by writing a 1 to the RXIC bit in the UARTICR register or by reading data from the receive FIFO until it becomes less than the trigger level, if the FIFO is enabled, or by reading a single byte if the FIFO is disabled. 890 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset Description 3:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CTSRIS RO 0 UART Clear to Send Modem Raw Interrupt Status Value Description 0 No interrupt 1 Clear to Send used for software flow control. This bit is cleared by writing a 1 to the CTSIC bit in the UARTICR register. This bit is implemented only on UART1 and is reserved for UART0 and UART2. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 12, 2014 891 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 12: UART Masked Interrupt Status (UARTMIS), offset 0x040 The UARTMIS register is the masked interrupt status register. On a read, this register gives the current masked status value of the corresponding interrupt. A write has no effect. UART Masked Interrupt Status (UARTMIS) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x040 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 reserved Type Reset RO 0 15 RO 0 RO 0 14 13 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 12 11 10 9 8 7 6 5 4 9BITMIS reserved OEMIS BEMIS PEMIS FEMIS RTMIS TXMIS RXMIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved RO 0 RO 0 1 0 CTSMIS reserved RO 0 RO 0 Bit/Field Name Type Reset Description 31:13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 9BITMIS RO 0 9-Bit Mode Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to a receive address match. This bit is cleared by writing a 1 to the 9BITIC bit in the UARTICR register. 11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 OEMIS RO 0 UART Overrun Error Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to an overrun error. This bit is cleared by writing a 1 to the OEIC bit in the UARTICR register. 892 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 9 BEMIS RO 0 Description UART Break Error Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to a break error. This bit is cleared by writing a 1 to the BEIC bit in the UARTICR register. 8 PEMIS RO 0 UART Parity Error Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to a parity error. This bit is cleared by writing a 1 to the PEIC bit in the UARTICR register. 7 FEMIS RO 0 UART Framing Error Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to a framing error. This bit is cleared by writing a 1 to the FEIC bit in the UARTICR register. 6 RTMIS RO 0 UART Receive Time-Out Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to a receive time out. This bit is cleared by writing a 1 to the RTIC bit in the UARTICR register. For receive timeout, the RTIM bit in the UARTIM register must be set to see the RTMIS status. 5 TXMIS RO 0 UART Transmit Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to passing through the specified transmit FIFO level (if the EOT bit is clear) or due to the transmission of the last data bit (if the EOT bit is set). This bit is cleared by writing a 1 to the TXIC bit in the UARTICR register or by writing data to the transmit FIFO until it becomes greater than the trigger level, if the FIFO is enabled, or by writing a single byte if the FIFO is disabled. June 12, 2014 893 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 4 RXMIS RO 0 Description UART Receive Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to passing through the specified receive FIFO level. This bit is cleared by writing a 1 to the RXIC bit in the UARTICR register or by reading data from the receive FIFO until it becomes less than the trigger level, if the FIFO is enabled, or by reading a single byte if the FIFO is disabled. 3:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CTSMIS RO 0 UART Clear to Send Modem Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to Clear to Send. This bit is cleared by writing a 1 to the CTSIC bit in the UARTICR register. This bit is implemented only on UART1 and is reserved for UART0 and UART2. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 894 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 13: UART Interrupt Clear (UARTICR), offset 0x044 The UARTICR register is the interrupt clear register. On a write of 1, the corresponding interrupt (both raw interrupt and masked interrupt, if enabled) is cleared. A write of 0 has no effect. UART Interrupt Clear (UARTICR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x044 Type W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 reserved Type Reset RO 0 15 RO 0 RO 0 14 13 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 12 11 10 9 8 7 6 5 4 9BITIC reserved OEIC BEIC PEIC FEIC RTIC TXIC RXIC RW 0 RO 0 W1C 0 W1C 0 W1C 0 W1C 0 W1C 0 W1C 0 W1C 0 RO 0 reserved RO 0 RO 0 1 0 CTSMIC reserved W1C 0 RO 0 Bit/Field Name Type Reset Description 31:13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 9BITIC RW 0 9-Bit Mode Interrupt Clear Writing a 1 to this bit clears the 9BITRIS bit in the UARTRIS register and the 9BITMIS bit in the UARTMIS register. 11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 OEIC W1C 0 Overrun Error Interrupt Clear Writing a 1 to this bit clears the OERIS bit in the UARTRIS register and the OEMIS bit in the UARTMIS register. 9 BEIC W1C 0 Break Error Interrupt Clear Writing a 1 to this bit clears the BERIS bit in the UARTRIS register and the BEMIS bit in the UARTMIS register. 8 PEIC W1C 0 Parity Error Interrupt Clear Writing a 1 to this bit clears the PERIS bit in the UARTRIS register and the PEMIS bit in the UARTMIS register. 7 FEIC W1C 0 Framing Error Interrupt Clear Writing a 1 to this bit clears the FERIS bit in the UARTRIS register and the FEMIS bit in the UARTMIS register. 6 RTIC W1C 0 Receive Time-Out Interrupt Clear Writing a 1 to this bit clears the RTRIS bit in the UARTRIS register and the RTMIS bit in the UARTMIS register. June 12, 2014 895 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 5 TXIC W1C 0 Description Transmit Interrupt Clear Writing a 1 to this bit clears the TXRIS bit in the UARTRIS register and the TXMIS bit in the UARTMIS register. 4 RXIC W1C 0 Receive Interrupt Clear Writing a 1 to this bit clears the RXRIS bit in the UARTRIS register and the RXMIS bit in the UARTMIS register. 3:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CTSMIC W1C 0 UART Clear to Send Modem Interrupt Clear Writing a 1 to this bit clears the CTSRIS bit in the UARTRIS register and the CTSMIS bit in the UARTMIS register. This bit is implemented only on UART1 and is reserved for UART0 and UART2. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 896 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 14: UART DMA Control (UARTDMACTL), offset 0x048 The UARTDMACTL register is the DMA control register. UART DMA Control (UARTDMACTL) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x048 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 2 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 9 8 7 6 5 4 3 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type 31:3 reserved RO 2 DMAERR RW RO 0 Reset DMAERR TXDMAE RXDMAE RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 Description 0x00000.000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 DMA on Error Value Description 1 TXDMAE RW 0 0 µDMA receive requests are unaffected when a receive error occurs. 1 µDMA receive requests are automatically disabled when a receive error occurs. Transmit DMA Enable Value Description 0 RXDMAE RW 0 0 µDMA for the transmit FIFO is disabled. 1 µDMA for the transmit FIFO is enabled. Receive DMA Enable Value Description 0 µDMA for the receive FIFO is disabled. 1 µDMA for the receive FIFO is enabled. June 12, 2014 897 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 15: UART 9-Bit Self Address (UART9BITADDR), offset 0x0A4 The UART9BITADDR register is used to write the specific address that should be matched with the receiving byte when the 9-bit Address Mask (UART9BITAMASK) is set to 0xFF. This register is used in conjunction with UART9BITAMASK to form a match for address-byte received. UART 9-Bit Self Address (UART9BITADDR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x0A4 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 15 14 13 12 9BITEN Type Reset RW 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 11 10 9 8 7 6 5 4 reserved RO 0 RO 0 RO 0 ADDR RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 9BITEN RW 0 RO 0 RW 0 RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Enable 9-Bit Mode Value Description 0 9-bit mode is disabled. 1 9-bit mode is enabled. 14:8 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 ADDR RW 0x00 Self Address for 9-Bit Mode This field contains the address that should be matched when UART9BITAMASK is 0xFF. 898 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 16: UART 9-Bit Self Address Mask (UART9BITAMASK), offset 0x0A8 The UART9BITAMASK register is used to enable the address mask for 9-bit mode. The address bits are masked to create a set of addresses to be matched with the received address byte. UART 9-Bit Self Address Mask (UART9BITAMASK) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0x0A8 Type RW, reset 0x0000.00FF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RW 1 RW 1 RW 1 RW 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 MASK RO 0 RO 0 RO 0 RO 0 RW 1 RW 1 RW 1 RW 1 Bit/Field Name Type Reset Description 31:8 reserved RO 0x00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 MASK RW 0xFF Self Address Mask for 9-Bit Mode This field contains the address mask that creates a set of addresses that should be matched. June 12, 2014 899 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 17: UART Peripheral Properties (UARTPP), offset 0xFC0 The UARTPP register provides information regarding the properties of the UART module. UART Peripheral Properties (UARTPP) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFC0 Type RO, reset 0x0000.0003 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:2 reserved RO 0x0000.000 1 NB RO 0x1 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 1 0 NB SC RO 1 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9-Bit Support Value Description 0 SC RO 0x1 0 The UART module does not provide support for the transmission of 9-bit data for RS-485 support. 1 The UART module provides support for the transmission of 9-bit data for RS-485 support. Smart Card Support Value Description 0 The UART module does not provide smart card support. 1 The UART module provides smart card support. 900 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 18: UART Clock Configuration (UARTCC), offset 0xFC8 The UARTCC register controls the baud clock source for the UART module. For more information, see the section called “Communication Clock Sources” on page 212. Note: If the PIOSC is used for the UART baud clock, the system clock frequency must be at least 9 MHz in Run mode. UART Clock Configuration (UARTCC) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFC8 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset CS Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3:0 CS RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Baud Clock Source The following table specifies the source that generates for the UART baud clock: Value Description 0x0 System clock (based on clock source and divisor factor) 0x1-0x4 reserved 0x5 PIOSC 0x5-0xF Reserved June 12, 2014 901 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 19: UART Peripheral Identification 4 (UARTPeriphID4), offset 0xFD0 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 4 (UARTPeriphID4) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFD0 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID4 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID4 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register [7:0] Can be used by software to identify the presence of this peripheral. 902 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 20: UART Peripheral Identification 5 (UARTPeriphID5), offset 0xFD4 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 5 (UARTPeriphID5) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFD4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID5 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID5 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register [15:8] Can be used by software to identify the presence of this peripheral. June 12, 2014 903 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 21: UART Peripheral Identification 6 (UARTPeriphID6), offset 0xFD8 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 6 (UARTPeriphID6) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFD8 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID6 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID6 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register [23:16] Can be used by software to identify the presence of this peripheral. 904 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 22: UART Peripheral Identification 7 (UARTPeriphID7), offset 0xFDC The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 7 (UARTPeriphID7) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFDC Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID7 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID7 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register [31:24] Can be used by software to identify the presence of this peripheral. June 12, 2014 905 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 23: UART Peripheral Identification 0 (UARTPeriphID0), offset 0xFE0 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 0 (UARTPeriphID0) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFE0 Type RO, reset 0x0000.0060 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID0 RO 0x60 RO 0 RO 0 RO 1 RO 1 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register [7:0] Can be used by software to identify the presence of this peripheral. 906 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 24: UART Peripheral Identification 1 (UARTPeriphID1), offset 0xFE4 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 1 (UARTPeriphID1) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFE4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID1 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID1 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register [15:8] Can be used by software to identify the presence of this peripheral. June 12, 2014 907 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 25: UART Peripheral Identification 2 (UARTPeriphID2), offset 0xFE8 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 2 (UARTPeriphID2) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFE8 Type RO, reset 0x0000.0018 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 1 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID2 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID2 RO 0x18 RO 0 RO 0 RO 0 RO 0 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register [23:16] Can be used by software to identify the presence of this peripheral. 908 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 26: UART Peripheral Identification 3 (UARTPeriphID3), offset 0xFEC The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 3 (UARTPeriphID3) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFEC Type RO, reset 0x0000.0001 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID3 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID3 RO 0x01 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register [31:24] Can be used by software to identify the presence of this peripheral. June 12, 2014 909 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 27: UART PrimeCell Identification 0 (UARTPCellID0), offset 0xFF0 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values. UART PrimeCell Identification 0 (UARTPCellID0) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFF0 Type RO, reset 0x0000.000D 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 1 RO 1 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CID0 RO 0x0D RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART PrimeCell ID Register [7:0] Provides software a standard cross-peripheral identification system. 910 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 28: UART PrimeCell Identification 1 (UARTPCellID1), offset 0xFF4 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values. UART PrimeCell Identification 1 (UARTPCellID1) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFF4 Type RO, reset 0x0000.00F0 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID1 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CID1 RO 0xF0 RO 0 RO 1 RO 1 RO 1 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART PrimeCell ID Register [15:8] Provides software a standard cross-peripheral identification system. June 12, 2014 911 Texas Instruments-Production Data Universal Asynchronous Receivers/Transmitters (UARTs) Register 29: UART PrimeCell Identification 2 (UARTPCellID2), offset 0xFF8 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values. UART PrimeCell Identification 2 (UARTPCellID2) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFF8 Type RO, reset 0x0000.0005 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 1 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID2 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CID2 RO 0x05 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART PrimeCell ID Register [23:16] Provides software a standard cross-peripheral identification system. 912 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 30: UART PrimeCell Identification 3 (UARTPCellID3), offset 0xFFC The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values. UART PrimeCell Identification 3 (UARTPCellID3) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 UART3 base: 0x4000.F000 UART4 base: 0x4001.0000 UART5 base: 0x4001.1000 UART6 base: 0x4001.2000 UART7 base: 0x4001.3000 Offset 0xFFC Type RO, reset 0x0000.00B1 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID3 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CID3 RO 0xB1 RO 0 RO 1 RO 0 RO 1 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART PrimeCell ID Register [31:24] Provides software a standard cross-peripheral identification system. June 12, 2014 913 Texas Instruments-Production Data Synchronous Serial Interface (SSI) 15 Synchronous Serial Interface (SSI) The TM4C1231H6PM microcontroller includes four Synchronous Serial Interface (SSI) modules. Each SSI module is a master or slave interface for synchronous serial communication with peripheral devices that have either Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces. The TM4C1231H6PM SSI modules have the following features: ■ Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces ■ Master or slave operation ■ Programmable clock bit rate and prescaler ■ Separate transmit and receive FIFOs, each 16 bits wide and 8 locations deep ■ Programmable data frame size from 4 to 16 bits ■ Internal loopback test mode for diagnostic/debug testing ■ Standard FIFO-based interrupts and End-of-Transmission interrupt ■ Efficient transfers using Micro Direct Memory Access Controller (µDMA) – Separate channels for transmit and receive – Receive single request asserted when data is in the FIFO; burst request asserted when FIFO contains 4 entries – Transmit single request asserted when there is space in the FIFO; burst request asserted when four or more entries are available to be written in the FIFO 914 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 15.1 Block Diagram Figure 15-1. SSI Module Block Diagram DMA Request DMA Control SSIDMACTL Interrupt Interrupt Control TxFIFO 8 x 16 SSIIM SSIMIS SSIRIS SSIICR . . . Control/Status SSInTx SSICR0 SSICR1 SSISR SSInRx Transmit/ Receive Logic SSIDR RxFIFO 8 x 16 Clock Prescaler System Clock SSInClk SSInFss . . . Clock Control SSICPSR SSICC PIOSC SSI Baud Clock Identification Registers SSIPCellID0 SSIPCellID1 SSIPCellID2 SSIPCellID3 15.2 SSIPeriphID0 SSIPeriphID1 SSIPeriphID2 SSIPeriphID3 SSIPeriphID4 SSIPeriphID5 SSIPeriphID6 SSIPeriphID7 Signal Description The following table lists the external signals of the SSI module and describes the function of each. Most SSI signals are alternate functions for some GPIO signals and default to be GPIO signals at June 12, 2014 915 Texas Instruments-Production Data Synchronous Serial Interface (SSI) reset. The exceptions to this rule are the SSI0Clk, SSI0Fss, SSI0Rx, and SSI0Tx pins, which default to the SSI function. The "Pin Mux/Pin Assignment" column in the following table lists the possible GPIO pin placements for the SSI signals. The AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register (page 636) should be set to choose the SSI function. The number in parentheses is the encoding that must be programmed into the PMCn field in the GPIO Port Control (GPIOPCTL) register (page 653) to assign the SSI signal to the specified GPIO port pin. For more information on configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 614. Table 15-1. SSI Signals (64LQFP) Pin Name Pin Number Pin Mux / Pin Assignment a Pin Type Buffer Type Description SSI0Clk 19 PA2 (2) I/O TTL SSI module 0 clock SSI0Fss 20 PA3 (2) I/O TTL SSI module 0 frame signal SSI0Rx 21 PA4 (2) I TTL SSI module 0 receive SSI0Tx 22 PA5 (2) O TTL SSI module 0 transmit SSI1Clk 30 61 PF2 (2) PD0 (2) I/O TTL SSI module 1 clock. SSI1Fss 31 62 PF3 (2) PD1 (2) I/O TTL SSI module 1 frame signal. SSI1Rx 28 63 PF0 (2) PD2 (2) I TTL SSI module 1 receive. SSI1Tx 29 64 PF1 (2) PD3 (2) O TTL SSI module 1 transmit. SSI2Clk 58 PB4 (2) I/O TTL SSI module 2 clock. SSI2Fss 57 PB5 (2) I/O TTL SSI module 2 frame signal. SSI2Rx 1 PB6 (2) I TTL SSI module 2 receive. SSI2Tx 4 PB7 (2) O TTL SSI module 2 transmit. SSI3Clk 61 PD0 (1) I/O TTL SSI module 3 clock. SSI3Fss 62 PD1 (1) I/O TTL SSI module 3 frame signal. SSI3Rx 63 PD2 (1) I TTL SSI module 3 receive. SSI3Tx 64 PD3 (1) O TTL SSI module 3 transmit. a. The TTL designation indicates the pin has TTL-compatible voltage levels. 15.3 Functional Description The SSI performs serial-to-parallel conversion on data received from a peripheral device. The CPU accesses data, control, and status information. The transmit and receive paths are buffered with internal FIFO memories allowing up to eight 16-bit values to be stored independently in both transmit and receive modes. The SSI also supports the µDMA interface. The transmit and receive FIFOs can be programmed as destination/source addresses in the µDMA module. µDMA operation is enabled by setting the appropriate bit(s) in the SSIDMACTL register (see page 945). 15.3.1 Bit Rate Generation The SSI includes a programmable bit rate clock divider and prescaler to generate the serial output clock. Bit rates are supported to 2 MHz and higher, although maximum bit rate is determined by peripheral devices. The serial bit rate is derived by dividing down the input clock (SysClk). The clock is first divided by an even prescale value CPSDVSR from 2 to 254, which is programmed in the SSI Clock Prescale 916 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller (SSICPSR) register (see page 938). The clock is further divided by a value from 1 to 256, which is 1 + SCR, where SCR is the value programmed in the SSI Control 0 (SSICR0) register (see page 931). The frequency of the output clock SSInClk is defined by: SSInClk = SysClk / (CPSDVSR * (1 + SCR)) Note: The System Clock or the PIOSC can be used as the source for the SSInClk. When the CS field in the SSI Clock Configuration (SSICC) register is configured to 0x5, PIOSC is selected as the source. For master mode, the system clock or the PIOSC must be at least two times faster than the SSInClk, with the restriction that SSInClk cannot be faster than 25 MHz. For slave mode, the system clock or the PIOSC must be at least 12 times faster than the SSInClk, with the restriction that SSInClk cannot be faster than 6.67 MHz. See “Synchronous Serial Interface (SSI)” on page 1130 to view SSI timing parameters. 15.3.2 FIFO Operation 15.3.2.1 Transmit FIFO The common transmit FIFO is a 16-bit wide, 8-locations deep, first-in, first-out memory buffer. The CPU writes data to the FIFO by writing the SSI Data (SSIDR) register (see page 935), and data is stored in the FIFO until it is read out by the transmission logic. When configured as a master or a slave, parallel data is written into the transmit FIFO prior to serial conversion and transmission to the attached slave or master, respectively, through the SSInTx pin. In slave mode, the SSI transmits data each time the master initiates a transaction. If the transmit FIFO is empty and the master initiates, the slave transmits the 8th most recent value in the transmit FIFO. If less than 8 values have been written to the transmit FIFO since the SSI module clock was enabled using the Rn bit in the RCGCSSI register, then 0 is transmitted. Care should be taken to ensure that valid data is in the FIFO as needed. The SSI can be configured to generate an interrupt or a µDMA request when the FIFO is empty. 15.3.2.2 Receive FIFO The common receive FIFO is a 16-bit wide, 8-locations deep, first-in, first-out memory buffer. Received data from the serial interface is stored in the buffer until read out by the CPU, which accesses the read FIFO by reading the SSIDR register. When configured as a master or slave, serial data received through the SSInRx pin is registered prior to parallel loading into the attached slave or master receive FIFO, respectively. 15.3.3 Interrupts The SSI can generate interrupts when the following conditions are observed: ■ Transmit FIFO service (when the transmit FIFO is half full or less) ■ Receive FIFO service (when the receive FIFO is half full or more) ■ Receive FIFO time-out ■ Receive FIFO overrun ■ End of transmission ■ Receive DMA transfer complete June 12, 2014 917 Texas Instruments-Production Data Synchronous Serial Interface (SSI) ■ Transmit DMA transfer complete All of the interrupt events are ORed together before being sent to the interrupt controller, so the SSI generates a single interrupt request to the controller regardless of the number of active interrupts. Each of the four individual maskable interrupts can be masked by clearing the appropriate bit in the SSI Interrupt Mask (SSIIM) register (see page 939). Setting the appropriate mask bit enables the interrupt. The individual outputs, along with a combined interrupt output, allow use of either a global interrupt service routine or modular device drivers to handle interrupts. The transmit and receive dynamic dataflow interrupts have been separated from the status interrupts so that data can be read or written in response to the FIFO trigger levels. The status of the individual interrupt sources can be read from the SSI Raw Interrupt Status (SSIRIS) and SSI Masked Interrupt Status (SSIMIS) registers (see page 940 and page 942, respectively). The receive FIFO has a time-out period that is 32 periods at the rate of SSInClk (whether or not SSInClk is currently active) and is started when the RX FIFO goes from EMPTY to not-EMPTY. If the RX FIFO is emptied before 32 clocks have passed, the time-out period is reset. As a result, the ISR should clear the Receive FIFO Time-out Interrupt just after reading out the RX FIFO by writing a 1 to the RTIC bit in the SSI Interrupt Clear (SSIICR) register. The interrupt should not be cleared so late that the ISR returns before the interrupt is actually cleared, or the ISR may be re-activated unnecessarily. The End-of-Transmission (EOT) interrupt indicates that the data has been transmitted completely and is only valid for Master mode devices/operations. This interrupt can be used to indicate when it is safe to turn off the SSI module clock or enter sleep mode. In addition, because transmitted data and received data complete at exactly the same time, the interrupt can also indicate that read data is ready immediately, without waiting for the receive FIFO time-out period to complete. Note: 15.3.4 In Freescale SPI mode only, a condition can be created where an EOT interrupt is generated for every byte transferred even if the FIFO is full. If the EOT bit has been set to 0 in an integrated slave SSI and the µDMA has been configured to transfer data from this SSI to a Master SSI on the device using external loopback, an EOT interrupt is generated by the SSI slave for every byte even if the FIFO is full. Frame Formats Each data frame is between 4 and 16 bits long depending on the size of data programmed and is transmitted starting with the MSB. There are three basic frame types that can be selected by programming the FRF bit in the SSICR0 register: ■ Texas Instruments synchronous serial ■ Freescale SPI ■ MICROWIRE For all three formats, the serial clock (SSInClk) is held inactive while the SSI is idle, and SSInClk transitions at the programmed frequency only during active transmission or reception of data. The idle state of SSInClk is utilized to provide a receive timeout indication that occurs when the receive FIFO still contains data after a timeout period. For Freescale SPI and MICROWIRE frame formats, the serial frame (SSInFss) pin is active Low, and is asserted (pulled down) during the entire transmission of the frame. 918 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller For Texas Instruments synchronous serial frame format, the SSInFss pin is pulsed for one serial clock period starting at its rising edge, prior to the transmission of each frame. For this frame format, both the SSI and the off-chip slave device drive their output data on the rising edge of SSInClk and latch data from the other device on the falling edge. Unlike the full-duplex transmission of the other two frame formats, the MICROWIRE format uses a special master-slave messaging technique which operates at half-duplex. In this mode, when a frame begins, an 8-bit control message is transmitted to the off-chip slave. During this transmit, no incoming data is received by the SSI. After the message has been sent, the off-chip slave decodes it and, after waiting one serial clock after the last bit of the 8-bit control message has been sent, responds with the requested data. The returned data can be 4 to 16 bits in length, making the total frame length anywhere from 13 to 25 bits. 15.3.4.1 Texas Instruments Synchronous Serial Frame Format Figure 15-2 on page 919 shows the Texas Instruments synchronous serial frame format for a single transmitted frame. Figure 15-2. TI Synchronous Serial Frame Format (Single Transfer) SSInClk SSInFss SSInTx/SSInRx MSB LSB 4 to 16 bits In this mode, SSInClk and SSInFss are forced Low, and the transmit data line SSInTx is tristated whenever the SSI is idle. Once the bottom entry of the transmit FIFO contains data, SSInFss is pulsed High for one SSInClk period. The value to be transmitted is also transferred from the transmit FIFO to the serial shift register of the transmit logic. On the next rising edge of SSInClk, the MSB of the 4 to 16-bit data frame is shifted out on the SSInTx pin. Likewise, the MSB of the received data is shifted onto the SSInRx pin by the off-chip serial slave device. Both the SSI and the off-chip serial slave device then clock each data bit into their serial shifter on each falling edge of SSInClk. The received data is transferred from the serial shifter to the receive FIFO on the first rising edge of SSInClk after the LSB has been latched. Figure 15-3 on page 920 shows the Texas Instruments synchronous serial frame format when back-to-back frames are transmitted. June 12, 2014 919 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Figure 15-3. TI Synchronous Serial Frame Format (Continuous Transfer) SSInClk SSInFss SSInTx/SSInRx MSB LSB 4 to 16 bits 15.3.4.2 Freescale SPI Frame Format The Freescale SPI interface is a four-wire interface where the SSInFss signal behaves as a slave select. The main feature of the Freescale SPI format is that the inactive state and phase of the SSInClk signal are programmable through the SPO and SPH bits in the SSICR0 control register. SPO Clock Polarity Bit When the SPO clock polarity control bit is clear, it produces a steady state Low value on the SSInClk pin. If the SPO bit is set, a steady state High value is placed on the SSInClk pin when data is not being transferred. SPH Phase Control Bit The SPH phase control bit selects the clock edge that captures data and allows it to change state. The state of this bit has the most impact on the first bit transmitted by either allowing or not allowing a clock transition before the first data capture edge. When the SPH phase control bit is clear, data is captured on the first clock edge transition. If the SPH bit is set, data is captured on the second clock edge transition. 15.3.4.3 Freescale SPI Frame Format with SPO=0 and SPH=0 Single and continuous transmission signal sequences for Freescale SPI format with SPO=0 and SPH=0 are shown in Figure 15-4 on page 921 and Figure 15-5 on page 921. 920 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 15-4. Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0 SSInClk SSInFss SSInRx LSB MSB Q 4 to 16 bits SSInTx MSB Note: LSB Q is undefined. Figure 15-5. Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0 SSInClk SSInFss SSInRx LSB LSB MSB MSB 4 to16 bits SSInTx LSB MSB LSB MSB In this configuration, during idle periods: ■ SSInClk is forced Low ■ SSInFss is forced High ■ The transmit data line SSInTx is tristated ■ When the SSI is configured as a master, it enables the SSInClk pad ■ When the SSI is configured as a slave, it disables the SSInClk pad If the SSI is enabled and valid data is in the transmit FIFO, the start of transmission is signified by the SSInFss master signal being driven Low, causing slave data to be enabled onto the SSInRx input line of the master. The master SSInTx output pad is enabled. One half SSInClk period later, valid master data is transferred to the SSInTx pin. Once both the master and slave data have been set, the SSInClk master clock pin goes High after one additional half SSInClk period. The data is now captured on the rising and propagated on the falling edges of the SSInClk signal. June 12, 2014 921 Texas Instruments-Production Data Synchronous Serial Interface (SSI) In the case of a single word transmission, after all bits of the data word have been transferred, the SSInFss line is returned to its idle High state one SSInClk period after the last bit has been captured. However, in the case of continuous back-to-back transmissions, the SSInFss signal must be pulsed High between each data word transfer because the slave select pin freezes the data in its serial peripheral register and does not allow it to be altered if the SPH bit is clear. Therefore, the master device must raise the SSInFss pin of the slave device between each data transfer to enable the serial peripheral data write. On completion of the continuous transfer, the SSInFss pin is returned to its idle state one SSInClk period after the last bit has been captured. 15.3.4.4 Freescale SPI Frame Format with SPO=0 and SPH=1 The transfer signal sequence for Freescale SPI format with SPO=0 and SPH=1 is shown in Figure 15-6 on page 922, which covers both single and continuous transfers. Figure 15-6. Freescale SPI Frame Format with SPO=0 and SPH=1 SSInClk SSInFss SSInRx Q Q MSB LSB Q 4 to 16 bits SSInTx LSB MSB Note: Q is undefined. In this configuration, during idle periods: ■ SSInClk is forced Low ■ SSInFss is forced High ■ The transmit data line SSInTx is tristated ■ When the SSI is configured as a master, it enables the SSInClk pad ■ When the SSI is configured as a slave, it disables the SSInClk pad If the SSI is enabled and valid data is in the transmit FIFO, the start of transmission is signified by the SSInFss master signal being driven Low. The master SSInTx output is enabled. After an additional one-half SSInClk period, both master and slave valid data are enabled onto their respective transmission lines. At the same time, the SSInClk is enabled with a rising edge transition. Data is then captured on the falling edges and propagated on the rising edges of the SSInClk signal. In the case of a single word transfer, after all bits have been transferred, the SSInFss line is returned to its idle High state one SSInClk period after the last bit has been captured. 922 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller For continuous back-to-back transfers, the SSInFss pin is held Low between successive data words, and termination is the same as that of the single word transfer. 15.3.4.5 Freescale SPI Frame Format with SPO=1 and SPH=0 Single and continuous transmission signal sequences for Freescale SPI format with SPO=1 and SPH=0 are shown in Figure 15-7 on page 923 and Figure 15-8 on page 923. Figure 15-7. Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0 SSInClk SSInFss SSInRx MSB LSB Q 4 to 16 bits SSInTx LSB MSB Note: Q is undefined. Figure 15-8. Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0 SSInClk SSInFss SSInTx/SSInRx LSB MSB LSB MSB 4 to 16 bits In this configuration, during idle periods: ■ SSInClk is forced High ■ SSInFss is forced High ■ The transmit data line SSInTx is tristated ■ When the SSI is configured as a master, it enables the SSInClk pad ■ When the SSI is configured as a slave, it disables the SSInClk pad If the SSI is enabled and valid data is in the transmit FIFO, the start of transmission is signified by the SSInFss master signal being driven Low, causing slave data to be immediately transferred onto the SSInRx line of the master. The master SSInTx output pad is enabled. One-half period later, valid master data is transferred to the SSInTx line. Once both the master and slave data have been set, the SSInClk master clock pin becomes Low after one additional half June 12, 2014 923 Texas Instruments-Production Data Synchronous Serial Interface (SSI) SSInClk period, meaning that data is captured on the falling edges and propagated on the rising edges of the SSInClk signal. In the case of a single word transmission, after all bits of the data word are transferred, the SSInFss line is returned to its idle High state one SSInClk period after the last bit has been captured. However, in the case of continuous back-to-back transmissions, the SSInFss signal must be pulsed High between each data word transfer because the slave select pin freezes the data in its serial peripheral register and does not allow it to be altered if the SPH bit is clear. Therefore, the master device must raise the SSInFss pin of the slave device between each data transfer to enable the serial peripheral data write. On completion of the continuous transfer, the SSInFss pin is returned to its idle state one SSInClk period after the last bit has been captured. 15.3.4.6 Freescale SPI Frame Format with SPO=1 and SPH=1 The transfer signal sequence for Freescale SPI format with SPO=1 and SPH=1 is shown in Figure 15-9 on page 924, which covers both single and continuous transfers. Figure 15-9. Freescale SPI Frame Format with SPO=1 and SPH=1 SSInClk SSInFss SSInRx Q MSB LSB Q 4 to 16 bits MSB SSInTx Note: LSB Q is undefined. In this configuration, during idle periods: ■ SSInClk is forced High ■ SSInFss is forced High ■ The transmit data line SSInTx is tristated ■ When the SSI is configured as a master, it enables the SSInClk pad ■ When the SSI is configured as a slave, it disables the SSInClk pad If the SSI is enabled and valid data is in the transmit FIFO, the start of transmission is signified by the SSInFss master signal being driven Low. The master SSInTx output pad is enabled. After an additional one-half SSInClk period, both master and slave data are enabled onto their respective transmission lines. At the same time, SSInClk is enabled with a falling edge transition. Data is then captured on the rising edges and propagated on the falling edges of the SSInClk signal. After all bits have been transferred, in the case of a single word transmission, the SSInFss line is returned to its idle high state one SSInClk period after the last bit has been captured. 924 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller For continuous back-to-back transmissions, the SSInFss pin remains in its active Low state until the final bit of the last word has been captured and then returns to its idle state as described above. For continuous back-to-back transfers, the SSInFss pin is held Low between successive data words and termination is the same as that of the single word transfer. 15.3.4.7 MICROWIRE Frame Format Figure 15-10 on page 925 shows the MICROWIRE frame format for a single frame. Figure 15-11 on page 926 shows the same format when back-to-back frames are transmitted. Figure 15-10. MICROWIRE Frame Format (Single Frame) SSInClk SSInFss SSInTx LSB MSB 8-bit control 0 SSInRx MSB LSB 4 to 16 bits output data MICROWIRE format is very similar to SPI format, except that transmission is half-duplex instead of full-duplex and uses a master-slave message passing technique. Each serial transmission begins with an 8-bit control word that is transmitted from the SSI to the off-chip slave device. During this transmission, no incoming data is received by the SSI. After the message has been sent, the off-chip slave decodes it and, after waiting one serial clock after the last bit of the 8-bit control message has been sent, responds with the required data. The returned data is 4 to 16 bits in length, making the total frame length anywhere from 13 to 25 bits. In this configuration, during idle periods: ■ SSInClk is forced Low ■ SSInFss is forced High ■ The transmit data line SSInTx is tristated A transmission is triggered by writing a control byte to the transmit FIFO. The falling edge of SSInFss causes the value contained in the bottom entry of the transmit FIFO to be transferred to the serial shift register of the transmit logic and the MSB of the 8-bit control frame to be shifted out onto the SSInTx pin. SSInFss remains Low for the duration of the frame transmission. The SSInRx pin remains tristated during this transmission. The off-chip serial slave device latches each control bit into its serial shifter on each rising edge of SSInClk. After the last bit is latched by the slave device, the control byte is decoded during a one clock wait-state, and the slave responds by transmitting data back to the SSI. Each bit is driven onto the SSInRx line on the falling edge of SSInClk. The SSI in turn latches each bit on the rising edge of SSInClk. At the end of the frame, for single transfers, the SSInFss signal is pulled High one clock period after the last bit has been latched in the receive serial shifter, causing the data to be transferred to the receive FIFO. June 12, 2014 925 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Note: The off-chip slave device can tristate the receive line either on the falling edge of SSInClk after the LSB has been latched by the receive shifter or when the SSInFss pin goes High. For continuous transfers, data transmission begins and ends in the same manner as a single transfer. However, the SSInFss line is continuously asserted (held Low) and transmission of data occurs back-to-back. The control byte of the next frame follows directly after the LSB of the received data from the current frame. Each of the received values is transferred from the receive shifter on the falling edge of SSInClk, after the LSB of the frame has been latched into the SSI. Figure 15-11. MICROWIRE Frame Format (Continuous Transfer) SSInClk SSInFss SSInTx LSB MSB LSB 8-bit control SSInRx 0 MSB MSB LSB 4 to 16 bits output data In the MICROWIRE mode, the SSI slave samples the first bit of receive data on the rising edge of SSInClk after SSInFss has gone Low. Masters that drive a free-running SSInClk must ensure that the SSInFss signal has sufficient setup and hold margins with respect to the rising edge of SSInClk. Figure 15-12 on page 926 illustrates these setup and hold time requirements. With respect to the SSInClk rising edge on which the first bit of receive data is to be sampled by the SSI slave, SSInFss must have a setup of at least two times the period of SSInClk on which the SSI operates. With respect to the SSInClk rising edge previous to this edge, SSInFss must have a hold of at least one SSInClk period. Figure 15-12. MICROWIRE Frame Format, SSInFss Input Setup and Hold Requirements tSetup=(2*tSSIClk) tHold=tSSIClk SSInClk SSInFss SSInRx First RX data to be sampled by SSI slave 15.3.5 DMA Operation The SSI peripheral provides an interface to the μDMA controller with separate channels for transmit and receive. The µDMA operation of the SSI is enabled through the SSI DMA Control (SSIDMACTL) register. When µDMA operation is enabled, the SSI asserts a µDMA request on the receive or transmit channel when the associated FIFO can transfer data. 926 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller For the receive channel, a single transfer request is asserted whenever any data is in the receive FIFO. A burst transfer request is asserted whenever the amount of data in the receive FIFO is 4 or more items. For the transmit channel, a single transfer request is asserted whenever at least one empty location is in the transmit FIFO. The burst request is asserted whenever the transmit FIFO has 4 or more empty slots. The single and burst µDMA transfer requests are handled automatically by the μDMA controller depending how the µDMA channel is configured. To enable µDMA operation for the receive channel, the RXDMAE bit of the DMA Control (SSIDMACTL) register should be set after configuring the µDMA. To enable µDMA operation for the transmit channel, the TXDMAE bit of SSIDMACTL should be set after configuring the µDMA. If µDMA is enabled, then the μDMA controller triggers an interrupt when a transfer is complete. The interrupt occurs on the SSI interrupt vector. Therefore, if interrupts are used for SSI operation and µDMA is enabled, the SSI interrupt handler must be designed to handle the μDMA completion interrupt. When transfers are performed from a FIFO of the SSI using the μDMA, and any interrupt is generated from the SSI, the SSI module's status bit in the DMA Channel Interrupt Status (DMACHIS) register must be checked at the end of the interrupt service routine. If the status bit is set, clear the interrupt by writing a 1 to it. See “Micro Direct Memory Access (μDMA)” on page 550 for more details about programming the μDMA controller. 15.4 Initialization and Configuration To enable and initialize the SSI, the following steps are necessary: 1. Enable the SSI module using the RCGCSSI register (see page 327). 2. Enable the clock to the appropriate GPIO module via the RCGCGPIO register (see page 321). To find out which GPIO port to enable, refer to Table 20-5 on page 1091. 3. Set the GPIO AFSEL bits for the appropriate pins (see page 636). To determine which GPIOs to configure, see Table 20-4 on page 1087. 4. Configure the PMCn fields in the GPIOPCTL register to assign the SSI signals to the appropriate pins. See page 653 and Table 20-5 on page 1091. 5. Program the GPIODEN register to enable the pin's digital function. In addition, the drive strength, drain select and pull-up/pull-down functions must be configured. Refer to “General-Purpose Input/Outputs (GPIOs)” on page 614 for more information. Note: Pull-ups can be used to avoid unnecessary toggles on the SSI pins, which can take the slave to a wrong state. In addition, if the SSIClk signal is programmed to steady state High through the SPO bit in the SSICR0 register, then software must also configure the GPIO port pin corresponding to the SSInClk signal as a pull-up in the GPIO Pull-Up Select (GPIOPUR) register. For each of the frame formats, the SSI is configured using the following steps: 1. Ensure that the SSE bit in the SSICR1 register is clear before making any configuration changes. 2. Select whether the SSI is a master or slave: a. For master operations, set the SSICR1 register to 0x0000.0000. June 12, 2014 927 Texas Instruments-Production Data Synchronous Serial Interface (SSI) b. For slave mode (output enabled), set the SSICR1 register to 0x0000.0004. c. For slave mode (output disabled), set the SSICR1 register to 0x0000.000C. 3. Configure the SSI clock source by writing to the SSICC register. 4. Configure the clock prescale divisor by writing the SSICPSR register. 5. Write the SSICR0 register with the following configuration: ■ Serial clock rate (SCR) ■ Desired clock phase/polarity, if using Freescale SPI mode (SPH and SPO) ■ The protocol mode: Freescale SPI, TI SSF, MICROWIRE (FRF) ■ The data size (DSS) 6. Optionally, configure the SSI module for μDMA use with the following steps: a. Configure a μDMA for SSI use. See “Micro Direct Memory Access (μDMA)” on page 550 for more information. b. Enable the SSI Module's TX FIFO or RX FIFO by setting the TXDMAE or RXDMAE bit in the SSIDMACTL register. 7. Enable the SSI by setting the SSE bit in the SSICR1 register. As an example, assume the SSI must be configured to operate with the following parameters: ■ Master operation ■ Freescale SPI mode (SPO=1, SPH=1) ■ 1 Mbps bit rate ■ 8 data bits Assuming the system clock is 20 MHz, the bit rate calculation would be: SSInClk = SysClk / (CPSDVSR * (1 + SCR)) 1x106 = 20x106 / (CPSDVSR * (1 + SCR)) In this case, if CPSDVSR=0x2, SCR must be 0x9. The configuration sequence would be as follows: 1. Ensure that the SSE bit in the SSICR1 register is clear. 2. Write the SSICR1 register with a value of 0x0000.0000. 3. Write the SSICPSR register with a value of 0x0000.0002. 4. Write the SSICR0 register with a value of 0x0000.09C7. 5. The SSI is then enabled by setting the SSE bit in the SSICR1 register. 928 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 15.5 Register Map Table 15-2 on page 929 lists the SSI registers. The offset listed is a hexadecimal increment to the register’s address, relative to that SSI module’s base address: ■ ■ ■ ■ SSI0: 0x4000.8000 SSI1: 0x4000.9000 SSI2: 0x4000.A000 SSI3: 0x4000.B000 Note that the SSI module clock must be enabled before the registers can be programmed (see page 327). The Rn bit of the PRSSI register must be read as 0x1 before any SSI module registers are accessed. Note: The SSI must be disabled (see the SSE bit in the SSICR1 register) before any of the control registers are reprogrammed. Table 15-2. SSI Register Map Type Reset Description See page SSICR0 RW 0x0000.0000 SSI Control 0 931 0x004 SSICR1 RW 0x0000.0000 SSI Control 1 933 0x008 SSIDR RW 0x0000.0000 SSI Data 935 0x00C SSISR RO 0x0000.0003 SSI Status 936 0x010 SSICPSR RW 0x0000.0000 SSI Clock Prescale 938 0x014 SSIIM RW 0x0000.0000 SSI Interrupt Mask 939 0x018 SSIRIS RO 0x0000.0008 SSI Raw Interrupt Status 940 0x01C SSIMIS RO 0x0000.0000 SSI Masked Interrupt Status 942 0x020 SSIICR W1C 0x0000.0000 SSI Interrupt Clear 944 0x024 SSIDMACTL RW 0x0000.0000 SSI DMA Control 945 0xFC8 SSICC RW 0x0000.0000 SSI Clock Configuration 946 0xFD0 SSIPeriphID4 RO 0x0000.0000 SSI Peripheral Identification 4 947 0xFD4 SSIPeriphID5 RO 0x0000.0000 SSI Peripheral Identification 5 948 0xFD8 SSIPeriphID6 RO 0x0000.0000 SSI Peripheral Identification 6 949 0xFDC SSIPeriphID7 RO 0x0000.0000 SSI Peripheral Identification 7 950 0xFE0 SSIPeriphID0 RO 0x0000.0022 SSI Peripheral Identification 0 951 0xFE4 SSIPeriphID1 RO 0x0000.0000 SSI Peripheral Identification 1 952 0xFE8 SSIPeriphID2 RO 0x0000.0018 SSI Peripheral Identification 2 953 0xFEC SSIPeriphID3 RO 0x0000.0001 SSI Peripheral Identification 3 954 0xFF0 SSIPCellID0 RO 0x0000.000D SSI PrimeCell Identification 0 955 0xFF4 SSIPCellID1 RO 0x0000.00F0 SSI PrimeCell Identification 1 956 Offset Name 0x000 June 12, 2014 929 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Table 15-2. SSI Register Map (continued) Offset Name 0xFF8 0xFFC 15.6 Description See page Type Reset SSIPCellID2 RO 0x0000.0005 SSI PrimeCell Identification 2 957 SSIPCellID3 RO 0x0000.00B1 SSI PrimeCell Identification 3 958 Register Descriptions The remainder of this section lists and describes the SSI registers, in numerical order by address offset. 930 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 1: SSI Control 0 (SSICR0), offset 0x000 The SSICR0 register contains bit fields that control various functions within the SSI module. Functionality such as protocol mode, clock rate, and data size are configured in this register. SSI Control 0 (SSICR0) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x000 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 5 4 3 2 1 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 15 14 13 12 RO 0 RO 0 RO 0 RO 0 11 10 9 8 SCR Type Reset RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:8 SCR RW 0x00 RW 0 RO 0 7 6 SPH SPO RW 0 RW 0 FRF RW 0 DSS RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Serial Clock Rate This bit field is used to generate the transmit and receive bit rate of the SSI. The bit rate is: BR=SysClk/(CPSDVSR * (1 + SCR)) where CPSDVSR is an even value from 2-254 programmed in the SSICPSR register, and SCR is a value from 0-255. 7 SPH RW 0 SSI Serial Clock Phase This bit is only applicable to the Freescale SPI Format. The SPH control bit selects the clock edge that captures data and allows it to change state. This bit has the most impact on the first bit transmitted by either allowing or not allowing a clock transition before the first data capture edge. Value Description 6 SPO RW 0 0 Data is captured on the first clock edge transition. 1 Data is captured on the second clock edge transition. SSI Serial Clock Polarity Value Description 0 A steady state Low value is placed on the SSInClk pin. 1 A steady state High value is placed on the SSInClk pin when data is not being transferred. Note: If this bit is set, then software must also configure the GPIO port pin corresponding to the SSInClk signal as a pull-up in the GPIO Pull-Up Select (GPIOPUR) register. June 12, 2014 931 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Bit/Field Name Type Reset 5:4 FRF RW 0x0 Description SSI Frame Format Select Value Frame Format 3:0 DSS RW 0x0 0x0 Freescale SPI Frame Format 0x1 Texas Instruments Synchronous Serial Frame Format 0x2 MICROWIRE Frame Format 0x3 Reserved SSI Data Size Select Value Data Size 0x0-0x2 Reserved 0x3 4-bit data 0x4 5-bit data 0x5 6-bit data 0x6 7-bit data 0x7 8-bit data 0x8 9-bit data 0x9 10-bit data 0xA 11-bit data 0xB 12-bit data 0xC 13-bit data 0xD 14-bit data 0xE 15-bit data 0xF 16-bit data 932 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 2: SSI Control 1 (SSICR1), offset 0x004 The SSICR1 register contains bit fields that control various functions within the SSI module. Master and slave mode functionality is controlled by this register. SSI Control 1 (SSICR1) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x004 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:5 reserved RO 0x0000.0 4 EOT RW 0 RO 0 RO 0 RO 0 RO 0 4 3 2 1 0 EOT reserved MS SSE LBM RW 0 RO 0 RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. End of Transmission This bit is only valid for Master mode devices and operations (MS = 0x0). Value Description 0 The TXRIS interrupt indicates that the transmit FIFO is half full or less. 1 The End of Transmit interrupt mode for the TXRIS interrupt is enabled. Note: In Freescale SPI mode only, a condition can be created where an EOT interrupt is generated for every byte transferred even if the FIFO is full. If the EOT bit has been set to 0 in an integrated slave SSI and the µDMA has been configured to transfer data from this SSI to a Master SSI on the device using external loopback, an EOT interrupt is generated by the SSI slave for every byte even if the FIFO is full. 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 MS RW 0 SSI Master/Slave Select This bit selects Master or Slave mode and can be modified only when the SSI is disabled (SSE=0). Value Description 0 The SSI is configured as a master. 1 The SSI is configured as a slave. June 12, 2014 933 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Bit/Field Name Type Reset 1 SSE RW 0 Description SSI Synchronous Serial Port Enable Value Description 0 SSI operation is disabled. 1 SSI operation is enabled. Note: 0 LBM RW 0 This bit must be cleared before any control registers are reprogrammed. SSI Loopback Mode Value Description 0 Normal serial port operation enabled. 1 Output of the transmit serial shift register is connected internally to the input of the receive serial shift register. 934 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 3: SSI Data (SSIDR), offset 0x008 Important: This register is read-sensitive. See the register description for details. The SSIDR register is 16-bits wide. When the SSIDR register is read, the entry in the receive FIFO that is pointed to by the current FIFO read pointer is accessed. When a data value is removed by the SSI receive logic from the incoming data frame, it is placed into the entry in the receive FIFO pointed to by the current FIFO write pointer. When the SSIDR register is written to, the entry in the transmit FIFO that is pointed to by the write pointer is written to. Data values are removed from the transmit FIFO one value at a time by the transmit logic. Each data value is loaded into the transmit serial shifter, then serially shifted out onto the SSInTx pin at the programmed bit rate. When a data size of less than 16 bits is selected, the user must right-justify data written to the transmit FIFO. The transmit logic ignores the unused bits. Received data less than 16 bits is automatically right-justified in the receive buffer. When the SSI is programmed for MICROWIRE frame format, the default size for transmit data is eight bits (the most significant byte is ignored). The receive data size is controlled by the programmer. The transmit FIFO and the receive FIFO are not cleared even when the SSE bit in the SSICR1 register is cleared, allowing the software to fill the transmit FIFO before enabling the SSI. SSI Data (SSIDR) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x008 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 DATA Type Reset RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 DATA RW 0x0000 SSI Receive/Transmit Data A read operation reads the receive FIFO. A write operation writes the transmit FIFO. Software must right-justify data when the SSI is programmed for a data size that is less than 16 bits. Unused bits at the top are ignored by the transmit logic. The receive logic automatically right-justifies the data. June 12, 2014 935 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 4: SSI Status (SSISR), offset 0x00C The SSISR register contains bits that indicate the FIFO fill status and the SSI busy status. SSI Status (SSISR) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x00C Type RO, reset 0x0000.0003 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:5 reserved RO 0x0000.00 4 BSY RO 0 RO 0 RO 0 RO 0 RO 0 4 3 2 1 0 BSY RFF RNE TNF TFE RO 0 RO 0 RO 0 RO 1 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Busy Bit Value Description 3 RFF RO 0 0 The SSI is idle. 1 The SSI is currently transmitting and/or receiving a frame, or the transmit FIFO is not empty. SSI Receive FIFO Full Value Description 2 RNE RO 0 0 The receive FIFO is not full. 1 The receive FIFO is full. SSI Receive FIFO Not Empty Value Description 1 TNF RO 1 0 The receive FIFO is empty. 1 The receive FIFO is not empty. SSI Transmit FIFO Not Full Value Description 0 The transmit FIFO is full. 1 The transmit FIFO is not full. 936 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 0 TFE RO 1 Description SSI Transmit FIFO Empty Value Description 0 The transmit FIFO is not empty. 1 The transmit FIFO is empty. June 12, 2014 937 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 5: SSI Clock Prescale (SSICPSR), offset 0x010 The SSICPSR register specifies the division factor which is used to derive the SSInClk from the system clock. The clock is further divided by a value from 1 to 256, which is 1 + SCR. SCR is programmed in the SSICR0 register. The frequency of the SSInClk is defined by: SSInClk = SysClk / (CPSDVSR * (1 + SCR)) The value programmed into this register must be an even number between 2 and 254. The least-significant bit of the programmed number is hard-coded to zero. If an odd number is written to this register, data read back from this register has the least-significant bit as zero. SSI Clock Prescale (SSICPSR) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x010 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset CPSDVSR RO 0 RW 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0x00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 CPSDVSR RW 0x00 SSI Clock Prescale Divisor This value must be an even number from 2 to 254, depending on the frequency of SSInClk. The LSB always returns 0 on reads. 938 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 6: SSI Interrupt Mask (SSIIM), offset 0x014 The SSIIM register is the interrupt mask set or clear register. It is a read/write register and all bits are cleared on reset. On a read, this register gives the current value of the mask on the corresponding interrupt. Setting a bit clears the mask, enabling the interrupt to be sent to the interrupt controller. Clearing a bit sets the corresponding mask, preventing the interrupt from being signaled to the controller. SSI Interrupt Mask (SSIIM) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x014 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 TXIM RXIM RTIM RORIM RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TXIM RW 0 SSI Transmit FIFO Interrupt Mask Value Description 2 RXIM RW 0 0 The transmit FIFO interrupt is masked. 1 The transmit FIFO interrupt is not masked. SSI Receive FIFO Interrupt Mask Value Description 1 RTIM RW 0 0 The receive FIFO interrupt is masked. 1 The receive FIFO interrupt is not masked. SSI Receive Time-Out Interrupt Mask Value Description 0 RORIM RW 0 0 The receive FIFO time-out interrupt is masked. 1 The receive FIFO time-out interrupt is not masked. SSI Receive Overrun Interrupt Mask Value Description 0 The receive FIFO overrun interrupt is masked. 1 The receive FIFO overrun interrupt is not masked. June 12, 2014 939 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 7: SSI Raw Interrupt Status (SSIRIS), offset 0x018 The SSIRIS register is the raw interrupt status register. On a read, this register gives the current raw status value of the corresponding interrupt prior to masking. A write has no effect. SSI Raw Interrupt Status (SSIRIS) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x018 Type RO, reset 0x0000.0008 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 1 0 TXRIS RXRIS RTRIS RORRIS RO 1 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TXRIS RO 1 SSI Transmit FIFO Raw Interrupt Status Value Description 0 No interrupt. 1 If the EOT bit in the SSICR1 register is clear, the transmit FIFO is half empty or less. If the EOT bit is set, the transmit FIFO is empty, and the last bit has been transmitted out of the serializer. This bit is cleared when the transmit FIFO is more than half full (if the EOT bit is clear) or when it has any data in it (if the EOT bit is set). 2 RXRIS RO 0 SSI Receive FIFO Raw Interrupt Status Value Description 0 No interrupt. 1 The receive FIFO is half full or more. This bit is cleared when the receive FIFO is less than half full. 1 RTRIS RO 0 SSI Receive Time-Out Raw Interrupt Status Value Description 0 No interrupt. 1 The receive time-out has occurred. This bit is cleared when a 1 is written to the RTIC bit in the SSI Interrupt Clear (SSIICR) register. 940 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 0 RORRIS RO 0 Description SSI Receive Overrun Raw Interrupt Status Value Description 0 No interrupt. 1 The receive FIFO has overflowed This bit is cleared when a 1 is written to the RORIC bit in the SSI Interrupt Clear (SSIICR) register. June 12, 2014 941 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 8: SSI Masked Interrupt Status (SSIMIS), offset 0x01C The SSIMIS register is the masked interrupt status register. On a read, this register gives the current masked status value of the corresponding interrupt. A write has no effect. SSI Masked Interrupt Status (SSIMIS) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x01C Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 1 0 TXMIS RXMIS RTMIS RORMIS RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TXMIS RO 0 SSI Transmit FIFO Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to the transmit FIFO being half empty or less (if the EOT bit is clear) or due to the transmission of the last data bit (if the EOT bit is set). This bit is cleared when the transmit FIFO is more than half empty (if the EOT bit is clear) or when it has any data in it (if the EOT bit is set). 2 RXMIS RO 0 SSI Receive FIFO Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to the receive FIFO being half full or more. This bit is cleared when the receive FIFO is less than half full. 1 RTMIS RO 0 SSI Receive Time-Out Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to the receive time out. This bit is cleared when a 1 is written to the RTIC bit in the SSI Interrupt Clear (SSIICR) register. 942 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 0 RORMIS RO 0 Description SSI Receive Overrun Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked interrupt was signaled due to the receive FIFO overflowing. This bit is cleared when a 1 is written to the RORIC bit in the SSI Interrupt Clear (SSIICR) register. June 12, 2014 943 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 9: SSI Interrupt Clear (SSIICR), offset 0x020 The SSIICR register is the interrupt clear register. On a write of 1, the corresponding interrupt is cleared. A write of 0 has no effect. SSI Interrupt Clear (SSIICR) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x020 Type W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 1 0 RTIC RORIC W1C 0 W1C 0 Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 RTIC W1C 0 SSI Receive Time-Out Interrupt Clear Writing a 1 to this bit clears the RTRIS bit in the SSIRIS register and the RTMIS bit in the SSIMIS register. 0 RORIC W1C 0 SSI Receive Overrun Interrupt Clear Writing a 1 to this bit clears the RORRIS bit in the SSIRIS register and the RORMIS bit in the SSIMIS register. 944 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 10: SSI DMA Control (SSIDMACTL), offset 0x024 The SSIDMACTL register is the µDMA control register. SSI DMA Control (SSIDMACTL) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0x024 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:2 reserved RO 0x0000.000 1 TXDMAE RW 0 TXDMAE RXDMAE RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Transmit DMA Enable Value Description 0 RXDMAE RW 0 0 µDMA for the transmit FIFO is disabled. 1 µDMA for the transmit FIFO is enabled. Receive DMA Enable Value Description 0 µDMA for the receive FIFO is disabled. 1 µDMA for the receive FIFO is enabled. June 12, 2014 945 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 11: SSI Clock Configuration (SSICC), offset 0xFC8 The SSICC register controls the baud clock source for the SSI module. Note: If the PIOSC is used for the SSI baud clock, the system clock frequency must be at least 16 MHz in Run mode. SSI Clock Configuration (SSICC) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFC8 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset CS Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3:0 CS RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Baud Clock Source The following table specifies the source that generates for the SSI baud clock: Value Description 0x0 System clock (based on clock source and divisor factor) 0x1-0x4 reserved 0x5 PIOSC 0x6 - 0xF Reserved 946 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 12: SSI Peripheral Identification 4 (SSIPeriphID4), offset 0xFD0 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 4 (SSIPeriphID4) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFD0 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID4 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID4 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [7:0] Can be used by software to identify the presence of this peripheral. June 12, 2014 947 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 13: SSI Peripheral Identification 5 (SSIPeriphID5), offset 0xFD4 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 5 (SSIPeriphID5) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFD4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID5 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID5 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [15:8] Can be used by software to identify the presence of this peripheral. 948 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 14: SSI Peripheral Identification 6 (SSIPeriphID6), offset 0xFD8 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 6 (SSIPeriphID6) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFD8 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID6 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID6 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [23:16] Can be used by software to identify the presence of this peripheral. June 12, 2014 949 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 15: SSI Peripheral Identification 7 (SSIPeriphID7), offset 0xFDC The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 7 (SSIPeriphID7) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFDC Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID7 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID7 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [31:24] Can be used by software to identify the presence of this peripheral. 950 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 16: SSI Peripheral Identification 0 (SSIPeriphID0), offset 0xFE0 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 0 (SSIPeriphID0) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFE0 Type RO, reset 0x0000.0022 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 1 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID0 RO 0x22 RO 0 RO 0 RO 0 RO 1 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [7:0] Can be used by software to identify the presence of this peripheral. June 12, 2014 951 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 17: SSI Peripheral Identification 1 (SSIPeriphID1), offset 0xFE4 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 1 (SSIPeriphID1) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFE4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID1 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID1 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [15:8] Can be used by software to identify the presence of this peripheral. 952 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 18: SSI Peripheral Identification 2 (SSIPeriphID2), offset 0xFE8 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 2 (SSIPeriphID2) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFE8 Type RO, reset 0x0000.0018 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 1 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID2 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID2 RO 0x18 RO 0 RO 0 RO 0 RO 0 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [23:16] Can be used by software to identify the presence of this peripheral. June 12, 2014 953 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 19: SSI Peripheral Identification 3 (SSIPeriphID3), offset 0xFEC The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 3 (SSIPeriphID3) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFEC Type RO, reset 0x0000.0001 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID3 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 PID3 RO 0x01 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [31:24] Can be used by software to identify the presence of this peripheral. 954 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 20: SSI PrimeCell Identification 0 (SSIPCellID0), offset 0xFF0 The SSIPCellIDn registers are hard-coded, and the fields within the register determine the reset value. SSI PrimeCell Identification 0 (SSIPCellID0) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFF0 Type RO, reset 0x0000.000D 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 1 RO 1 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CID0 RO 0x0D RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI PrimeCell ID Register [7:0] Provides software a standard cross-peripheral identification system. June 12, 2014 955 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 21: SSI PrimeCell Identification 1 (SSIPCellID1), offset 0xFF4 The SSIPCellIDn registers are hard-coded, and the fields within the register determine the reset value. SSI PrimeCell Identification 1 (SSIPCellID1) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFF4 Type RO, reset 0x0000.00F0 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID1 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CID1 RO 0xF0 RO 0 RO 1 RO 1 RO 1 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI PrimeCell ID Register [15:8] Provides software a standard cross-peripheral identification system. 956 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 22: SSI PrimeCell Identification 2 (SSIPCellID2), offset 0xFF8 The SSIPCellIDn registers are hard-coded, and the fields within the register determine the reset value. SSI PrimeCell Identification 2 (SSIPCellID2) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFF8 Type RO, reset 0x0000.0005 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 1 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID2 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CID2 RO 0x05 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI PrimeCell ID Register [23:16] Provides software a standard cross-peripheral identification system. June 12, 2014 957 Texas Instruments-Production Data Synchronous Serial Interface (SSI) Register 23: SSI PrimeCell Identification 3 (SSIPCellID3), offset 0xFFC The SSIPCellIDn registers are hard-coded, and the fields within the register determine the reset value. SSI PrimeCell Identification 3 (SSIPCellID3) SSI0 base: 0x4000.8000 SSI1 base: 0x4000.9000 SSI2 base: 0x4000.A000 SSI3 base: 0x4000.B000 Offset 0xFFC Type RO, reset 0x0000.00B1 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID3 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CID3 RO 0xB1 RO 0 RO 1 RO 0 RO 1 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI PrimeCell ID Register [31:24] Provides software a standard cross-peripheral identification system. 958 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 16 Inter-Integrated Circuit (I2C) Interface The Inter-Integrated Circuit (I2C) bus provides bi-directional data transfer through a two-wire design (a serial data line SDA and a serial clock line SCL), and interfaces to external I2C devices such as serial memory (RAMs and ROMs), networking devices, LCDs, tone generators, and so on. The I2C bus may also be used for system testing and diagnostic purposes in product development and manufacturing. The TM4C1231H6PM microcontroller includes providing the ability to communicate (both transmit and receive) with other I2C devices on the bus. The TM4C1231H6PM controller includes I2C modules with the following features: ■ Devices on the I2C bus can be designated as either a master or a slave – Supports both transmitting and receiving data as either a master or a slave – Supports simultaneous master and slave operation ■ Four I2C modes – Master transmit – Master receive – Slave transmit – Slave receive ■ Four transmission speeds: – Standard (100 Kbps) – Fast-mode (400 Kbps) – Fast-mode plus (1 Mbps) – High-speed mode (3.33 Mbps) ■ Clock low timeout interrupt ■ Dual slave address capability ■ Glitch suppression ■ Master and slave interrupt generation – Master generates interrupts when a transmit or receive operation completes (or aborts due to an error) – Slave generates interrupts when data has been transferred or requested by a master or when a START or STOP condition is detected ■ Master with arbitration and clock synchronization, multimaster support, and 7-bit addressing mode June 12, 2014 959 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface 16.1 Block Diagram Figure 16-1. I2C Block Diagram I2CSCL I2C Control Interrupt I2CMSA I2CSOAR I2CMCS I2CSCSR I2CMDR I2CSDR I2CMTPR I2CSIMR I2CMIMR I2CSRIS I2CMRIS I2CSMIS I2CMMIS I2CSICR I2CMICR I2CPP I2C Master Core I2CSDA I2CSCL 2 I C I/O Select I2CSDA I2CSCL I2C Slave Core I2CSDA I2CMCR 16.2 Signal Description The following table lists the external signals of the I2C interface and describes the function of each. The I2C interface signals are alternate functions for some GPIO signals and default to be GPIO signals at reset, with the exception of the I2C0SCL and I2CSDA pins which default to the I2C function. The column in the table below titled "Pin Mux/Pin Assignment" lists the possible GPIO pin placements for the I2C signals. The AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register (page 636) should be set to choose the I2C function. The number in parentheses is the encoding that must be programmed into the PMCn field in the GPIO Port Control (GPIOPCTL) register (page 653) to assign the I2C signal to the specified GPIO port pin. Note that the I2CSDA pin should be set to open drain using the GPIO Open Drain Select (GPIOODR) register. For more information on configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 614. Table 16-1. I2C Signals (64LQFP) Pin Name Pin Number Pin Mux / Pin Assignment a Pin Type Buffer Type Description I2C0SCL 47 PB2 (3) I/O OD I2C module 0 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C0SDA 48 PB3 (3) I/O OD I2C module 0 data. I2C1SCL 23 PA6 (3) I/O OD I2C module 1 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C1SDA 24 PA7 (3) I/O OD I2C module 1 data. I2C2SCL 59 PE4 (3) I/O OD I2C module 2 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C2SDA 60 PE5 (3) I/O OD I2C module 2 data. I2C3SCL 61 PD0 (3) I/O OD I2C module 3 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C3SDA 62 PD1 (3) I/O OD I2C module 3 data. a. The TTL designation indicates the pin has TTL-compatible voltage levels. 960 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 16.3 Functional Description Each I2C module is comprised of both master and slave functions and is identified by a unique address. A master-initiated communication generates the clock signal, SCL. For proper operation, the SDA pin must be configured as an open-drain signal. Due to the internal circuitry that supports high-speed operation, the SCL pin must not be configured as an open-drain signal, although the internal circuitry causes it to act as if it were an open drain signal. Both SDA and SCL signals must be connected to a positive supply voltage using a pull-up resistor. A typical I2C bus configuration is shown in Figure 16-2. Refer to the I2C-bus specification and user manual to determine the size of the pull-ups needed for proper operation. See “Inter-Integrated Circuit (I2C) Interface” on page 1133 for I2C timing diagrams. Figure 16-2. I2C Bus Configuration RPUP SCL SDA I2C Bus I2CSCL I2CSDA Tiva™ Microcontroller 16.3.1 RPUP SCL SDA 3rd Party Device with I2C Interface SCL SDA 3rd Party Device with I2C Interface I2C Bus Functional Overview The I2C bus uses only two signals: SDA and SCL, named I2CSDA and I2CSCL on TM4C1231H6PM microcontrollers. SDA is the bi-directional serial data line and SCL is the bi-directional serial clock line. The bus is considered idle when both lines are High. Every transaction on the I2C bus is nine bits long, consisting of eight data bits and a single acknowledge bit. The number of bytes per transfer (defined as the time between a valid START and STOP condition, described in “START and STOP Conditions” on page 961) is unrestricted, but each data byte has to be followed by an acknowledge bit, and data must be transferred MSB first. When a receiver cannot receive another complete byte, it can hold the clock line SCL Low and force the transmitter into a wait state. The data transfer continues when the receiver releases the clock SCL. 16.3.1.1 START and STOP Conditions The protocol of the I2C bus defines two states to begin and end a transaction: START and STOP. A High-to-Low transition on the SDA line while the SCL is High is defined as a START condition, and a Low-to-High transition on the SDA line while SCL is High is defined as a STOP condition. The bus is considered busy after a START condition and free after a STOP condition. See Figure 16-3. Figure 16-3. START and STOP Conditions SDA SDA SCL SCL START condition STOP condition June 12, 2014 961 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface The STOP bit determines if the cycle stops at the end of the data cycle or continues on to a repeated START condition. To generate a single transmit cycle, the I2C Master Slave Address (I2CMSA) register is written with the desired address, the R/S bit is cleared, and the Control register is written with ACK=X (0 or 1), STOP=1, START=1, and RUN=1 to perform the operation and stop. When the operation is completed (or aborted due an error), the interrupt pin becomes active and the data may be read from the I2C Master Data (I2CMDR) register. When the I2C module operates in Master receiver mode, the ACK bit is normally set causing the I2C bus controller to transmit an acknowledge automatically after each byte. This bit must be cleared when the I2C bus controller requires no further data to be transmitted from the slave transmitter. When operating in slave mode, the STARTRIS and STOPRIS bits in the I2C Slave Raw Interrupt Status (I2CSRIS) register indicate detection of start and stop conditions on the bus and the I2C Slave Masked Interrupt Status (I2CSMIS) register can be configured to allow STARTRIS and STOPRIS to be promoted to controller interrupts (when interrupts are enabled). 16.3.1.2 Data Format with 7-Bit Address Data transfers follow the format shown in Figure 16-4. After the START condition, a slave address is transmitted. This address is 7-bits long followed by an eighth bit, which is a data direction bit (R/S bit in the I2CMSA register). If the R/S bit is clear, it indicates a transmit operation (send), and if it is set, it indicates a request for data (receive). A data transfer is always terminated by a STOP condition generated by the master, however, a master can initiate communications with another device on the bus by generating a repeated START condition and addressing another slave without first generating a STOP condition. Various combinations of receive/transmit formats are then possible within a single transfer. Figure 16-4. Complete Data Transfer with a 7-Bit Address SDA MSB SCL 1 2 LSB R/S ACK 7 8 9 MSB 1 2 Slave address Start 7 Data LSB ACK 8 9 Stop The first seven bits of the first byte make up the slave address (see Figure 16-5). The eighth bit determines the direction of the message. A zero in the R/S position of the first byte means that the master transmits (sends) data to the selected slave, and a one in this position means that the master receives data from the slave. Figure 16-5. R/S Bit in First Byte MSB LSB R/S Slave address 16.3.1.3 Data Validity The data on the SDA line must be stable during the high period of the clock, and the data line can only change when SCL is Low (see Figure 16-6). 962 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 16-6. Data Validity During Bit Transfer on the I2C Bus SDA SCL 16.3.1.4 Data line Change stable of data allowed Acknowledge All bus transactions have a required acknowledge clock cycle that is generated by the master. During the acknowledge cycle, the transmitter (which can be the master or slave) releases the SDA line. To acknowledge the transaction, the receiver must pull down SDA during the acknowledge clock cycle. The data transmitted out by the receiver during the acknowledge cycle must comply with the data validity requirements described in “Data Validity” on page 962. When a slave receiver does not acknowledge the slave address, SDA must be left High by the slave so that the master can generate a STOP condition and abort the current transfer. If the master device is acting as a receiver during a transfer, it is responsible for acknowledging each transfer made by the slave. Because the master controls the number of bytes in the transfer, it signals the end of data to the slave transmitter by not generating an acknowledge on the last data byte. The slave transmitter must then release SDA to allow the master to generate the STOP or a repeated START condition. If the slave is required to provide a manual ACK or NACK, the I2C Slave ACK Control (I2CSACKCTL) register allows the slave to NACK for invalid data or command or ACK for valid data or command. When this operation is enabled, the MCU slave module I2C clock is pulled low after the last data bit until this register is written with the indicated response. 16.3.1.5 Repeated Start The I2C master module has the capability of executing a repeated START (transmit or receive) after an initial transfer has occurred. A repeated start sequence for a Master transmit is as follows: 1. When the device is in the idle state, the Master writes the slave address to the I2CMSA register and configures the R/S bit for the desired transfer type. 2. Data is written to the I2CMDR register. 3. When the BUSY bit in the I2CMCS register is 0 , the Master writes 0x3 to the I2CMCS register to initiate a transfer. 4. The Master does not generate a STOP condition but instead writes another slave address to the I2CMSA register and then writes 0x3 to initiate the repeated START. A repeated start sequence for a Master receive is similar: 1. When the device is in idle, the Master writes the slave address to the I2CMSA register and configures the R/S bit for the desired transfer type. 2. The master reads data from the I2CMDR register. June 12, 2014 963 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface 3. When the BUSY bit in the I2CMCS register is 0 , the Master writes 0x3 to the I2CMCS register to initiate a transfer. 4. The Master does not generate a STOP condition but instead writes another slave address to the I2CMSA register and then writes 0x3 to initiate the repeated START. For more information on repeated START, refer to Figure 16-12 on page 974 and Figure 16-13 on page 975. 16.3.1.6 Clock Low Timeout (CLTO) The I2C slave can extend the transaction by pulling the clock low periodically to create a slow bit transfer rate. The I2C module has a 12-bit programmable counter that is used to track how long the clock has been held low. The upper 8 bits of the count value are software programmable through the I2C Master Clock Low Timeout Count (I2CMCLKOCNT) register. The lower four bits are not user visible and are 0x0. The CNTL value programmed in the I2CMCLKOCNT register has to be greater than 0x01. The application can program the eight most significant bits of the counter to reflect the acceptable cumulative low period in transaction. The count is loaded at the START condition and counts down on each falling edge of the internal bus clock of the Master. Note that the internal bus clock generated for this counter keeps running at the programmed I2C speed even if SCL is held low on the bus. Upon reaching terminal count, the master state machine forces ABORT on the bus by issuing a STOP condition at the instance of SCL and SDA release. As an example, if an I2C module was operating at 100 kHz speed, programming the I2CMCLKOCNT register to 0xDA would translate to the value 0xDA0 since the lower four bits are set to 0x0. This would translate to a decimal value of 3488 clocks or a cumulative clock low period of 34.88 ms at 100 kHz. The CLKRIS bit in the I2C Master Raw Interrupt Status (I2CMRIS) register is set when the clock timeout period is reached, allowing the master to start corrective action to resolve the remote slave state. In addition, the CLKTO bit in the I2C Master Control/Status (I2CMCS) register is set; this bit is cleared when a STOP condition is sent or during the I2C master reset. The status of the raw SDA and SCL signals are readable by software through the SDA and SCL bits in the I2C Master Bus Monitor (I2CMBMON) register to help determine the state of the remote slave. In the event of a CLTO condition, application software must choose how it intends to attempt bus recovery. Most applications may attempt to manually toggle the I2C pins to force the slave to let go of the clock signal (a common solution is to attempt to force a STOP on the bus). If a CLTO is detected before the end of a burst transfer, and the bus is successfully recovered by the master, the master hardware attempts to finish the pending burst operation. Depending on the state of the slave after bus recovery, the actual behavior on the bus varies. If the slave resumes in a state where it can acknowledge the master (essentially, where it was before the bus hang), it continues where it left off. However, if the slave resumes in a reset state (or if a forced STOP by the master causes the slave to enter the idle state), it may ignore the master's attempt to complete the burst operation and NAK the first data byte that the master sends or requests. Since the behavior of slaves cannot always be predicted, it is suggested that the application software always write the STOP bit in the I2C Master Configuration (I2CMCR) register during the CLTO interrupt service routine. This limits the amount of data the master attempts to send or receive upon bus recovery to a single byte, and after the single byte is on the wire, the master issues a STOP. An alternative solution is to have the application software reset the I2C peripheral before attempting to manually recover the bus. This solution allows the I2C master hardware to be returned to a known good (and idle) state before attempting to recover a stuck bus and prevents any unwanted data from appearing on the wire. 964 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Note: 16.3.1.7 The Master Clock Low Timeout counter counts for the entire time SCL is held Low continuously. If SCL is deasserted at any point, the Master Clock Low Timeout Counter is reloaded with the value in the I2CMCLKOCNT register and begins counting down from this value. Dual Address The I2C interface supports dual address capability for the slave. The additional programmable address is provided and can be matched if enabled. In legacy mode with dual address disabled, the I2C slave provides an ACK on the bus if the address matches the OAR field in the I2CSOAR register. In dual address mode, the I2C slave provides an ACK on the bus if either the OAR field in the I2CSOAR register or the OAR2 field in the I2CSOAR2 register is matched. The enable for dual address is programmable through the OAR2EN bit in the I2CSOAR2 register and there is no disable on the legacy address. The OAR2SEL bit in the I2CSCSR register indicates if the address that was ACKed is the alternate address or not. When this bit is clear, it indicates either legacy operation or no address match. 16.3.1.8 Arbitration A master may start a transfer only if the bus is idle. It's possible for two or more masters to generate a START condition within minimum hold time of the START condition. In these situations, an arbitration scheme takes place on the SDA line, while SCL is High. During arbitration, the first of the competing master devices to place a 1 (High) on SDA, while another master transmits a 0 (Low), switches off its data output stage and retires until the bus is idle again. Arbitration can take place over several bits. Its first stage is a comparison of address bits, and if both masters are trying to address the same device, arbitration continues on to the comparison of data bits. 16.3.1.9 Glitch Suppression in Multi-Master Configuration When a multi-master configuration is being used, the GFE bit in the I2C Master Configuration (I2CMCR) register can be set to enable glitch suppression on the SCL and SDA lines and assure proper signal values. The filter can be programmed to different filter widths using the GFPW bit in the I2C Master Configuration 2 (I2CMCR2) register. The glitch suppression value is in terms of buffered system clocks. Note that all signals will be delayed internally when glitch suppression is nonzero. For example, if GFPW is set to 0x7, 31 clocks should be added onto the calculation for the expected transaction time. 16.3.2 Available Speed Modes The I2C bus can run in Standard mode (100 kbps), Fast mode (400 kbps), Fast mode plus (1 Mbps) or High-Speed mode (3.33 Mbps). The selected mode should match the speed of the other I2C devices on the bus. 16.3.2.1 Standard, Fast, and Fast Plus Modes Standard, Fast, and Fast Plus modes are selected using a value in the I2C Master Timer Period (I2CMTPR) register that results in an SCL frequency of 100 kbps for Standard mode, 400 kbps for Fast mode, or 1 Mbps for Fast mode plus. The I2C clock rate is determined by the parameters CLK_PRD, TIMER_PRD, SCL_LP, and SCL_HP where: CLK_PRD is the system clock period June 12, 2014 965 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface SCL_LP is the low phase of SCL (fixed at 6) SCL_HP is the high phase of SCL (fixed at 4) TIMER_PRD is the programmed value in the I2CMTPR register (see page 988). This value is determined by replacing the known variables in the equation below and solving for TIMER_PRD. The I2C clock period is calculated as follows: SCL_PERIOD = 2 × (1 + TIMER_PRD) × (SCL_LP + SCL_HP) × CLK_PRD For example: CLK_PRD = 50 ns TIMER_PRD = 2 SCL_LP=6 SCL_HP=4 yields a SCL frequency of: 1/SCL_PERIOD = 333 Khz Table 16-2 gives examples of the timer periods that should be used to generate Standard, Fast mode, and Fast mode plus SCL frequencies based on various system clock frequencies. Table 16-2. Examples of I2C Master Timer Period Versus Speed Mode 16.3.2.2 System Clock Timer Period Standard Mode Timer Period Fast Mode Timer Period Fast Mode Plus 4 MHz 0x01 100 Kbps - - - - 6 MHz 0x02 100 Kbps - - - - 12.5 MHz 0x06 89 Kbps 0x01 312 Kbps - - 16.7 MHz 0x08 93 Kbps 0x02 278 Kbps - - 20 MHz 0x09 100 Kbps 0x02 333 Kbps - - 25 MHz 0x0C 96.2 Kbps 0x03 312 Kbps - - 33 MHz 0x10 97.1 Kbps 0x04 330 Kbps - - 40 MHz 0x13 100 Kbps 0x04 400 Kbps 0x01 1000 Kbps 50 MHz 0x18 100 Kbps 0x06 357 Kbps 0x02 833 Kbps 80 MHz 0x27 100 Kbps 0x09 400 Kbps 0x03 1000 Kbps High-Speed Mode The TM4C1231H6PM I2C peripheral has support for High-speed operation as both a master and slave. High-Speed mode is configured by setting the HS bit in the I2C Master Control/Status (I2CMCS) register. High-Speed mode transmits data at a high bit rate with a 66.6%/33.3% duty cycle, but communication and arbitration are done at Standard, Fast mode, or Fast-mode plus speed, depending on which is selected by the user. When the HS bit in the I2CMCS register is set, current mode pull-ups are enabled. The clock period can be selected using the equation below, but in this case, SCL_LP=2 and SCL_HP=1. SCL_PERIOD = 2 × (1 + TIMER_PRD) × (SCL_LP + SCL_HP) × CLK_PRD So for example: 966 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller CLK_PRD = 25 ns TIMER_PRD = 1 SCL_LP=2 SCL_HP=1 yields a SCL frequency of: 1/T = 3.33 Mhz Table 16-3 on page 967 gives examples of timer period and system clock in High-Speed mode. Note that the HS bit in the I2CMTPR register needs to be set for the TPR value to be used in High-Speed mode. Table 16-3. Examples of I2C Master Timer Period in High-Speed Mode System Clock Timer Period Transmission Mode 40 MHz 0x01 3.33 Mbps 50 MHz 0x02 2.77 Mbps 80 MHz 0x03 3.33 Mbps When operating as a master, the protocol is shown in Figure 16-7. The master is responsible for sending a master code byte in either Standard (100 Kbps) or Fast-mode (400 Kbps) before it begins transferring in High-speed mode. The master code byte must contain data in the form of 0000.1XXX and is used to tell the slave devices to prepare for a High-speed transfer. The master code byte should never be acknowledged by a slave since it is only used to indicate that the upcoming data is going to be transferred at a higher data rate. To send the master code byte, software should place the value of the master code byte into the I2CMSA register and write the I2CMCS register with a value of 0x13. This places the I2C master peripheral in High-speed mode, and all subsequent transfers (until STOP) are carried out at High-speed data rate using the normal I2CMCS command bits, without setting the HS bit in the I2CMCS register. Again, setting the HS bit in the I2CMCS register is only necessary during the master code byte. When operating as a High-speed slave, there is no additional software required. Figure 16-7. High-Speed Data Format R/W SDA Device-Specific NAK Address Data SCL Standard (100 KHz) or Fast Mode (400 KHz) High Speed (3.3 Mbps) Note: 16.3.3 High-Speed mode is 3.4 Mbps, provided correct system clock frequency is set and there is appropriate pull strength on SCL and SDA lines. Interrupts The I2C can generate interrupts when the following conditions are observed: ■ Master transaction completed ■ Master arbitration lost June 12, 2014 967 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface ■ Master transaction error ■ Master bus timeout ■ Slave transaction received ■ Slave transaction requested ■ Stop condition on bus detected ■ Start condition on bus detected The I2C master and I2C slave modules have separate interrupt signals. While both modules can generate interrupts for multiple conditions, only a single interrupt signal is sent to the interrupt controller. 16.3.3.1 I2C Master Interrupts The I2C master module generates an interrupt when a transaction completes (either transmit or receive), when arbitration is lost, or when an error occurs during a transaction. To enable the I2C master interrupt, software must set the IM bit in the I2C Master Interrupt Mask (I2CMIMR) register. When an interrupt condition is met, software must check the ERROR and ARBLST bits in the I2C Master Control/Status (I2CMCS) register to verify that an error didn't occur during the last transaction and to ensure that arbitration has not been lost. An error condition is asserted if the last transaction wasn't acknowledged by the slave. If an error is not detected and the master has not lost arbitration, the application can proceed with the transfer. The interrupt is cleared by writing a 1 to the IC bit in the I2C Master Interrupt Clear (I2CMICR) register. If the application doesn't require the use of interrupts, the raw interrupt status is always visible via the I2C Master Raw Interrupt Status (I2CMRIS) register. 16.3.3.2 I2C Slave Interrupts The slave module can generate an interrupt when data has been received or requested. This interrupt is enabled by setting the DATAIM bit in the I2C Slave Interrupt Mask (I2CSIMR) register. Software determines whether the module should write (transmit) or read (receive) data from the I2C Slave Data (I2CSDR) register, by checking the RREQ and TREQ bits of the I2C Slave Control/Status (I2CSCSR) register. If the slave module is in receive mode and the first byte of a transfer is received, the FBR bit is set along with the RREQ bit. The interrupt is cleared by setting the DATAIC bit in the I2C Slave Interrupt Clear (I2CSICR) register. In addition, the slave module can generate an interrupt when a start and stop condition is detected. These interrupts are enabled by setting the STARTIM and STOPIM bits of the I2C Slave Interrupt Mask (I2CSIMR) register and cleared by writing a 1 to the STOPIC and STARTIC bits of the I2C Slave Interrupt Clear (I2CSICR) register. If the application doesn't require the use of interrupts, the raw interrupt status is always visible via the I2C Slave Raw Interrupt Status (I2CSRIS) register. 16.3.4 Loopback Operation The I2C modules can be placed into an internal loopback mode for diagnostic or debug work by setting the LPBK bit in the I2C Master Configuration (I2CMCR) register. In loopback mode, the SDA and SCL signals from the master and are tied to the SDA and SCL signals of the slave module to allow internal testing of the device without having to go through I/O. 968 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 16.3.5 Command Sequence Flow Charts This section details the steps required to perform the various I2C transfer types in both master and slave mode. 16.3.5.1 I2C Master Command Sequences The figures that follow show the command sequences available for the I2C master. June 12, 2014 969 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Figure 16-8. Master Single TRANSMIT Idle Write Slave Address to I2CMSA Sequence may be omitted in a Single Master system Write data to I2CMDR Read I2CMCS NO BUSBSY bit=0? YES Write ---0-111 to I2CMCS Read I2CMCS NO BUSY bit=0? YES Error Service NO ERROR bit=0? YES Idle 970 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 16-9. Master Single RECEIVE Idle Write Slave Address to I2CMSA Sequence may be omitted in a Single Master system Read I2CMCS NO BUSBSY bit=0? YES Write ---00111 to I2CMCS Read I2CMCS NO BUSY bit=0? YES Error Service NO ERROR bit=0? YES Read data from I2CMDR Idle June 12, 2014 971 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Figure 16-10. Master TRANSMIT of Multiple Data Bytes Idle Write Slave Address to I2CMSA Sequence may be omitted in a Single Master system Read I2CMCS Write data to I2CMDR BUSY bit=0? YES Read I2CMCS ERROR bit=0? NO NO NO BUSBSY bit=0? YES Write data to I2CMDR YES Write ---0-011 to I2CMCS NO ARBLST bit=1? YES Write ---0-001 to I2CMCS NO Index=n? YES Write ---0-101 to I2CMCS Write ---0-100 to I2CMCS Error Service Idle Read I2CMCS NO BUSY bit=0? YES Error Service NO ERROR bit=0? YES Idle 972 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 16-11. Master RECEIVE of Multiple Data Bytes Idle Write Slave Address to I2CMSA Sequence may be omitted in a Single Master system Read I2CMCS BUSY bit=0? Read I2CMCS NO YES NO BUSBSY bit=0? ERROR bit=0? NO YES Write ---01011 to I2CMCS NO Read data from I2CMDR ARBLST bit=1? YES Write ---01001 to I2CMCS NO Write ---0-100 to I2CMCS Index=m-1? Error Service YES Write ---00101 to I2CMCS Idle Read I2CMCS BUSY bit=0? NO YES NO ERROR bit=0? YES Error Service Read data from I2CMDR Idle June 12, 2014 973 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Figure 16-12. Master RECEIVE with Repeated START after Master TRANSMIT Idle Master operates in Master Transmit mode STOP condition is not generated Write Slave Address to I2CMSA Write ---01011 to I2CMCS Master operates in Master Receive mode Repeated START condition is generated with changing data direction Idle 974 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 16-13. Master TRANSMIT with Repeated START after Master RECEIVE Idle Master operates in Master Receive mode STOP condition is not generated Write Slave Address to I2CMSA Write ---0-011 to I2CMCS Master operates in Master Transmit mode Repeated START condition is generated with changing data direction Idle June 12, 2014 975 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Figure 16-14. Standard High Speed Mode Master Transmit IDLE write slave address to I2CMSA register Master code and arbitration is always done in FAST or STANDARD mode write „---10011” to I2CMCS register read I2CMCS register no Busy=’0' yes no IDLE Error=’0' yes Normal sequence starts here. The sequence below covers SINGLE send write Slave Address to I2MSA register write Data to I2CMDR register write „---0-111” to I2CMCS register read I2CMCS register no Busy=’0' yes yes IDLE Error=’0' no Error service IDLE 976 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 16.3.5.2 I2C Slave Command Sequences Figure 16-15 on page 977 presents the command sequence available for the I2C slave. Figure 16-15. Slave Command Sequence Idle Write OWN Slave Address to I2CSOAR Write -------1 to I2CSCSR Read I2CSCSR NO TREQ bit=1? YES Write data to I2CSDR NO RREQ bit=1? FBR is also valid YES Read data from I2CSDR 16.4 Initialization and Configuration 16.4.1 Configure the I2C Module to Transmit a Single Byte as a Master The following example shows how to configure the I2C module to transmit a single byte as a master. This assumes the system clock is 20 MHz. 1. Enable the I2C clock using the RCGCI2C register in the System Control module (see page 329). 2. Enable the clock to the appropriate GPIO module via the RCGCGPIO register in the System Control module (see page 321). To find out which GPIO port to enable, refer to Table 20-5 on page 1091. 3. In the GPIO module, enable the appropriate pins for their alternate function using the GPIOAFSEL register (see page 636). To determine which GPIOs to configure, see Table 20-4 on page 1087. June 12, 2014 977 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface 4. Enable the I2CSDA pin for open-drain operation. See page 641. 5. Configure the PMCn fields in the GPIOPCTL register to assign the I2C signals to the appropriate pins. See page 653 and Table 20-5 on page 1091. 6. Initialize the I2C Master by writing the I2CMCR register with a value of 0x0000.0010. 7. Set the desired SCL clock speed of 100 Kbps by writing the I2CMTPR register with the correct value. The value written to the I2CMTPR register represents the number of system clock periods in one SCL clock period. The TPR value is determined by the following equation: TPR = (System Clock/(2*(SCL_LP + SCL_HP)*SCL_CLK))-1; TPR = (20MHz/(2*(6+4)*100000))-1; TPR = 9 Write the I2CMTPR register with the value of 0x0000.0009. 8. Specify the slave address of the master and that the next operation is a Transmit by writing the I2CMSA register with a value of 0x0000.0076. This sets the slave address to 0x3B. 9. Place data (byte) to be transmitted in the data register by writing the I2CMDR register with the desired data. 10. Initiate a single byte transmit of the data from Master to Slave by writing the I2CMCS register with a value of 0x0000.0007 (STOP, START, RUN). 11. Wait until the transmission completes by polling the I2CMCS register's BUSBSY bit until it has been cleared. 12. Check the ERROR bit in the I2CMCS register to confirm the transmit was acknowledged. 16.4.2 Configure the I2C Master to High Speed Mode To configure the I2C master to High Speed mode: 1. Enable the I2C clock using the RCGCI2C register in the System Control module (see page 329). 2. Enable the clock to the appropriate GPIO module via the RCGCGPIO register in the System Control module (see page 321). To find out which GPIO port to enable, refer to Table 20-5 on page 1091. 3. In the GPIO module, enable the appropriate pins for their alternate function using the GPIOAFSEL register (see page 636). To determine which GPIOs to configure, see Table 20-4 on page 1087. 4. Enable the I2CSDA pin for open-drain operation. See page 641. 5. Configure the PMCn fields in the GPIOPCTL register to assign the I2C signals to the appropriate pins. See page 653 and Table 20-5 on page 1091. 6. Initialize the I2C Master by writing the I2CMCR register with a value of 0x0000.0010. 7. Set the desired SCL clock speed of 3.33 Mbps by writing the I2CMTPR register with the correct value. The value written to the I2CMTPR register represents the number of system clock periods in one SCL clock period. The TPR value is determined by the following equation: 978 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller TPR = (System Clock/(2*(SCL_LP + SCL_HP)*SCL_CLK))-1; TPR = (80 MHz/(2*(2+1)*3330000))-1; TPR = 3 Write the I2CMTPR register with the value of 0x0000.0003. 8. To send the master code byte, software should place the value of the master code byte into the I2CMSA register and write the I2CMCS register with a value of 0x13. 9. This places the I2C master peripheral in High-speed mode, and all subsequent transfers (until STOP) are carried out at High-speed data rate using the normal I2CMCS command bits, without setting the HS bit in the I2CMCS register. 10. The transaction is ended by setting the STOP bit in the I2CMCS register. 11. Wait until the transmission completes by polling the I2CMCS register's BUSBSY bit until it has been cleared. 12. Check the ERROR bit in the I2CMCS register to confirm the transmit was acknowledged. 16.5 Register Map Table 16-4 on page 979 lists the I2C registers. All addresses given are relative to the I2C base address: ■ ■ ■ ■ I2C 0: 0x4002.0000 I2C 1: 0x4002.1000 I2C 2: 0x4002.2000 I2C 3: 0x4002.3000 Note that the I2C module clock must be enabled before the registers can be programmed (see page 329). There must be a delay of 3 system clocks after the I2C module clock is enabled before any I2C module registers are accessed. The hw_i2c.h file in the TivaWare™ Driver Library uses a base address of 0x800 for the I2C slave registers. Be aware when using registers with offsets between 0x800 and 0x818 that TivaWare™ for C Series uses an offset between 0x000 and 0x018 with the slave base address. Table 16-4. Inter-Integrated Circuit (I2C) Interface Register Map Offset Name Type Reset Description See page I2C Master 0x000 I2CMSA RW 0x0000.0000 I2C Master Slave Address 981 0x004 I2CMCS RW 0x0000.0020 I2C Master Control/Status 982 0x008 I2CMDR RW 0x0000.0000 I2C Master Data 987 0x00C I2CMTPR RW 0x0000.0001 I2C Master Timer Period 988 0x010 I2CMIMR RW 0x0000.0000 I2C Master Interrupt Mask 989 0x014 I2CMRIS RO 0x0000.0000 I2C Master Raw Interrupt Status 990 0x018 I2CMMIS RO 0x0000.0000 I2C Master Masked Interrupt Status 991 June 12, 2014 979 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Table 16-4. Inter-Integrated Circuit (I2C) Interface Register Map (continued) Description See page Offset Name Type Reset 0x01C I2CMICR WO 0x0000.0000 I2C Master Interrupt Clear 992 0x020 I2CMCR RW 0x0000.0000 I2C Master Configuration 993 0x024 I2CMCLKOCNT RW 0x0000.0000 I2C Master Clock Low Timeout Count 995 0x02C I2CMBMON RO 0x0000.0003 I2C Master Bus Monitor 996 0x038 I2CMCR2 RW 0x0000.0000 I2C Master Configuration 2 997 0x800 I2CSOAR RW 0x0000.0000 I2C Slave Own Address 998 0x804 I2CSCSR RO 0x0000.0000 I2C Slave Control/Status 999 0x808 I2CSDR RW 0x0000.0000 I2C Slave Data 1001 0x80C I2CSIMR RW 0x0000.0000 I2C Slave Interrupt Mask 1002 0x810 I2CSRIS RO 0x0000.0000 I2C Slave Raw Interrupt Status 1003 0x814 I2CSMIS RO 0x0000.0000 I2C Slave Masked Interrupt Status 1004 0x818 I2CSICR WO 0x0000.0000 I2C Slave Interrupt Clear 1005 0x81C I2CSOAR2 RW 0x0000.0000 I2C Slave Own Address 2 1006 0x820 I2CSACKCTL RW 0x0000.0000 I2C Slave ACK Control 1007 I2C Slave I2C Status and Control 0xFC0 I2CPP RO 0x0000.0001 I2C Peripheral Properties 1008 0xFC4 I2CPC RO 0x0000.0001 I2C Peripheral Configuration 1009 16.6 Register Descriptions (I2C Master) The remainder of this section lists and describes the I2C master registers, in numerical order by address offset. 980 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 1: I2C Master Slave Address (I2CMSA), offset 0x000 This register consists of eight bits: seven address bits (A6-A0), and a Receive/Send bit, which determines if the next operation is a Receive (High), or Transmit (Low). I2C Master Slave Address (I2CMSA) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x000 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset SA RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:1 SA RW 0x00 R/S RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. I2C Slave Address This field specifies bits A6 through A0 of the slave address. 0 R/S RW 0 Receive/Send The R/S bit specifies if the next master operation is a Receive (High) or Transmit (Low). Value Description 0 Transmit 1 Receive June 12, 2014 981 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 2: I2C Master Control/Status (I2CMCS), offset 0x004 This register accesses status bits when read and control bits when written. When read, the status register indicates the state of the I2C bus controller. When written, the control register configures the I2C controller operation. The START bit generates the START or REPEATED START condition. The STOP bit determines if the cycle stops at the end of the data cycle or continues to the next transfer cycle, which could be a repeated START. To generate a single transmit cycle, the I2C Master Slave Address (I2CMSA) register is written with the desired address, the R/S bit is cleared, and this register is written with ACK=X (0 or 1), STOP=1, START=1, and RUN=1 to perform the operation and stop. When the operation is completed (or aborted due an error), an interrupt becomes active and the data may be read from the I2CMDR register. When the I2C module operates in Master receiver mode, the ACK bit is normally set, causing the I2C bus controller to transmit an acknowledge automatically after each byte. This bit must be cleared when the I2C bus controller requires no further data to be transmitted from the slave transmitter. Read-Only Status Register I2C Master Control/Status (I2CMCS) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x004 Type RO, reset 0x0000.0020 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 CLKTO BUSBSY IDLE ARBLST ERROR BUSY RO 0 RO 0 RO 1 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 CLKTO RO 0 DATACK ADRACK RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Clock Timeout Error Value Description 0 No clock timeout error. 1 The clock timeout error has occurred. This bit is cleared when the master sends a STOP condition or if the I2C master is reset. 982 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 6 BUSBSY RO 0 Description Bus Busy Value Description 0 The I2C bus is idle. 1 The I2C bus is busy. The bit changes based on the START and STOP conditions. 5 IDLE RO 1 I2C Idle Value Description 4 ARBLST RO 0 0 The I2C controller is not idle. 1 The I2C controller is idle. Arbitration Lost Value Description 3 DATACK RO 0 0 The I2C controller won arbitration. 1 The I2C controller lost arbitration. Acknowledge Data Value Description 2 ADRACK RO 0 0 The transmitted data was acknowledged 1 The transmitted data was not acknowledged. Acknowledge Address Value Description 1 ERROR RO 0 0 The transmitted address was acknowledged 1 The transmitted address was not acknowledged. Error Value Description 0 No error was detected on the last operation. 1 An error occurred on the last operation. The error can be from the slave address not being acknowledged or the transmit data not being acknowledged. 0 BUSY RO 0 I2C Busy Value Description 0 The controller is idle. 1 The controller is busy. When the BUSY bit is set, the other status bits are not valid. June 12, 2014 983 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Write-Only Control Register I2C Master Control/Status (I2CMCS) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x004 Type WO, reset 0x0000.0020 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 4 3 2 1 0 HS ACK STOP START RUN WO 0 WO 0 WO 0 WO 0 WO 0 Bit/Field Name Type Reset Description 31:5 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 HS WO 0 High-Speed Enable Value Description 3 ACK WO 0 0 The master operates in Standard, Fast mode, or Fast mode plus as selected by using a value in the I2CMTPR register that results in an SCL frequency of 100 kbps for Standard mode, 400 kbps for Fast mode, or 1 Mpbs for Fast mode plus. 1 The master operates in High-Speed mode with transmission speeds up to 3.33 Mbps. Data Acknowledge Enable Value Description 2 STOP WO 0 0 The received data byte is not acknowledged automatically by the master. 1 The received data byte is acknowledged automatically by the master. See field decoding in Table 16-5 on page 985. Generate STOP Value Description 0 The controller does not generate the STOP condition. 1 The controller generates the STOP condition. See field decoding in Table 16-5 on page 985. 984 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 1 START WO 0 Description Generate START Value Description 0 RUN WO 0 The controller does not generate the START condition. 1 The controller generates the START or repeated START condition. See field decoding in Table 16-5 on page 985. I2C Master Enable 0 Value Description 0 This encoding means the master is unable to transmit or receive data. 1 The master is able to transmit or receive data. See field decoding in Table 16-5 on page 985. Table 16-5. Write Field Decoding for I2CMCS[3:0] Field Current I2CMSA[0] State R/S Idle I2CMCS[3:0] ACK STOP START RUN Description 0 X a 0 1 1 START condition followed by TRANSMIT (master goes to the Master Transmit state). 0 X 1 1 1 START condition followed by a TRANSMIT and STOP condition (master remains in Idle state). 1 0 0 1 1 START condition followed by RECEIVE operation with negative ACK (master goes to the Master Receive state). 1 0 1 1 1 START condition followed by RECEIVE and STOP condition (master remains in Idle state). 1 1 0 1 1 START condition followed by RECEIVE (master goes to the Master Receive state). 1 1 1 1 1 Illegal All other combinations not listed are non-operations. NOP June 12, 2014 985 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Table 16-5. Write Field Decoding for I2CMCS[3:0] Field (continued) Current I2CMSA[0] State R/S Master Transmit I2CMCS[3:0] Description ACK STOP START RUN X X 0 0 1 TRANSMIT operation (master remains in Master Transmit state). X X 1 0 0 STOP condition (master goes to Idle state). X X 1 0 1 TRANSMIT followed by STOP condition (master goes to Idle state). 0 X 0 1 1 Repeated START condition followed by a TRANSMIT (master remains in Master Transmit state). 0 X 1 1 1 Repeated START condition followed by TRANSMIT and STOP condition (master goes to Idle state). 1 0 0 1 1 Repeated START condition followed by a RECEIVE operation with a negative ACK (master goes to Master Receive state). 1 0 1 1 1 Repeated START condition followed by a TRANSMIT and STOP condition (master goes to Idle state). 1 1 0 1 1 Repeated START condition followed by RECEIVE (master goes to Master Receive state). 1 1 1 1 1 Illegal. All other combinations not listed are non-operations. NOP. X 0 0 0 1 RECEIVE operation with negative ACK (master remains in Master Receive state). X X 1 0 0 STOP condition (master goes to Idle state). X 0 1 0 1 RECEIVE followed by STOP condition (master goes to Idle state). X 1 0 0 1 RECEIVE operation (master remains in Master Receive state). X 1 1 0 1 Illegal. 1 0 0 1 1 Repeated START condition followed by RECEIVE operation with a negative ACK (master remains in Master Receive state). 1 0 1 1 1 Repeated START condition followed by RECEIVE and STOP condition (master goes to Idle state). 1 1 0 1 1 Repeated START condition followed by RECEIVE (master remains in Master Receive state). 0 X 0 1 1 Repeated START condition followed by TRANSMIT (master goes to Master Transmit state). 0 X 1 1 1 Repeated START condition followed by TRANSMIT and STOP condition (master goes to Idle state). Master Receive All other combinations not listed are non-operations. b NOP. a. An X in a table cell indicates the bit can be 0 or 1. b. In Master Receive mode, a STOP condition should be generated only after a Data Negative Acknowledge executed by the master or an Address Negative Acknowledge executed by the slave. 986 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 3: I2C Master Data (I2CMDR), offset 0x008 Important: This register is read-sensitive. See the register description for details. This register contains the data to be transmitted when in the Master Transmit state and the data received when in the Master Receive state. I2C Master Data (I2CMDR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x008 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset DATA RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 DATA RW 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. This byte contains the data transferred during a transaction. June 12, 2014 987 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 4: I2C Master Timer Period (I2CMTPR), offset 0x00C This register is programmed to set the timer period for the SCL clock and assign the SCL clock to either standard or high-speed mode. I2C Master Timer Period (I2CMTPR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x00C Type RW, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 WO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 1 reserved Type Reset reserved Type Reset HS RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 HS WO 0x0 TPR RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. High-Speed Enable Value Description 6:0 TPR RW 0x1 0 The SCL Clock Period set by TPR applies to Standard mode (100 Kbps), Fast-mode (400 Kbps), or Fast-mode plus (1 Mbps). 1 The SCL Clock Period set by TPR applies to High-speed mode (3.33 Mbps). Timer Period This field is used in the equation to configure SCL_PERIOD: SCL_PERIOD = 2×(1 + TPR)×(SCL_LP + SCL_HP)×CLK_PRD where: SCL_PRD is the SCL line period (I2C clock). TPR is the Timer Period register value (range of 1 to 127). SCL_LP is the SCL Low period (fixed at 6). SCL_HP is the SCL High period (fixed at 4). CLK_PRD is the system clock period in ns. 988 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 5: I2C Master Interrupt Mask (I2CMIMR), offset 0x010 This register controls whether a raw interrupt is promoted to a controller interrupt. I2C Master Interrupt Mask (I2CMIMR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x010 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset CLKIM IM RW 0 RW 0 Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CLKIM RW 0 Clock Timeout Interrupt Mask Value Description 0 IM RW 0 0 The CLKRIS interrupt is suppressed and not sent to the interrupt controller. 1 The clock timeout interrupt is sent to the interrupt controller when the CLKRIS bit in the I2CMRIS register is set. Master Interrupt Mask Value Description 0 The RIS interrupt is suppressed and not sent to the interrupt controller. 1 The master interrupt is sent to the interrupt controller when the RIS bit in the I2CMRIS register is set. June 12, 2014 989 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 6: I2C Master Raw Interrupt Status (I2CMRIS), offset 0x014 This register specifies whether an interrupt is pending. I2C Master Raw Interrupt Status (I2CMRIS) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x014 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 CLKRIS RIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CLKRIS RO 0 Clock Timeout Raw Interrupt Status Value Description 0 No interrupt. 1 The clock timeout interrupt is pending. This bit is cleared by writing a 1 to the CLKIC bit in the I2CMICR register. 0 RIS RO 0 Master Raw Interrupt Status Value Description 0 No interrupt. 1 A master interrupt is pending. This bit is cleared by writing a 1 to the IC bit in the I2CMICR register. 990 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 7: I2C Master Masked Interrupt Status (I2CMMIS), offset 0x018 This register specifies whether an interrupt was signaled. I2C Master Masked Interrupt Status (I2CMMIS) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x018 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 CLKMIS MIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CLKMIS RO 0 Clock Timeout Masked Interrupt Status Value Description 0 No interrupt. 1 An unmasked clock timeout interrupt was signaled and is pending. This bit is cleared by writing a 1 to the CLKIC bit in the I2CMICR register. 0 MIS RO 0 Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked master interrupt was signaled and is pending. This bit is cleared by writing a 1 to the IC bit in the I2CMICR register. June 12, 2014 991 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 8: I2C Master Interrupt Clear (I2CMICR), offset 0x01C This register clears the raw and masked interrupts. I2C Master Interrupt Clear (I2CMICR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x01C Type WO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset CLKIC IC WO 0 WO 0 Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CLKIC WO 0 Clock Timeout Interrupt Clear Writing a 1 to this bit clears the CLKRIS bit in the I2CMRIS register and the CLKMIS bit in the I2CMMIS register. A read of this register returns no meaningful data. 0 IC WO 0 Master Interrupt Clear Writing a 1 to this bit clears the RIS bit in the I2CMRIS register and the MIS bit in the I2CMMIS register. A read of this register returns no meaningful data. 992 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 9: I2C Master Configuration (I2CMCR), offset 0x020 This register configures the mode (Master or Slave), enables the glitch filter, and sets the interface for test mode loopback. I2C Master Configuration (I2CMCR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x020 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 GFE SFE MFE RO 0 RO 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset 31:7 reserved RO 0x0000.00 6 GFE RW 0 reserved RO 0 RO 0 LPBK RO 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. I2C Glitch Filter Enable Value Description 0 I2C glitch filter is disabled. 1 I2C glitch filter is enabled. Use the GFPW bit in the I2C Master Configuration 2 (I2CMCR2) register to program the pulse width. 5 SFE RW 0 I2C Slave Function Enable Value Description 4 MFE RW 0 0 Slave mode is disabled. 1 Slave mode is enabled. I2C Master Function Enable Value Description 3:1 reserved RO 0x0 0 Master mode is disabled. 1 Master mode is enabled. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 12, 2014 993 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Bit/Field Name Type Reset 0 LPBK RW 0 Description I2C Loopback Value Description 0 Normal operation. 1 The controller in a test mode loopback configuration. 994 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 10: I2C Master Clock Low Timeout Count (I2CMCLKOCNT), offset 0x024 This register contains the upper 8 bits of a 12-bit counter that can be used to keep the timeout limit for clock stretching by a remote slave. The lower four bits of the counter are not user visible and are always 0x0. Note: The Master Clock Low Timeout counter counts for the entire time SCL is held Low continuously. If SCL is deasserted at any point, the Master Clock Low Timeout Counter is reloaded with the value in the I2CMCLKOCNT register and begins counting down from this value. I2C Master Clock Low Timeout Count (I2CMCLKOCNT) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x024 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset CNTL RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 CNTL RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. I2C Master Count This field contains the upper 8 bits of a 12-bit counter for the clock low timeout count. Note: The value of CNTL must be greater than 0x1. June 12, 2014 995 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 11: I2C Master Bus Monitor (I2CMBMON), offset 0x02C This register is used to determine the SCL and SDA signal status. I2C Master Bus Monitor (I2CMBMON) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x02C Type RO, reset 0x0000.0003 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 SDA SCL RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:2 reserved RO 0x0000.000 1 SDA RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. I2C SDA Status Value Description 0 SCL RO 1 0 The I2CSDA signal is low. 1 The I2CSDA signal is high. I2C SCL Status Value Description 0 The I2CSCL signal is low. 1 The I2CSCL signal is high. 996 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 12: I2C Master Configuration 2 (I2CMCR2), offset 0x038 This register can be programmed to select the pulse width for glitch suppression, measured in system clocks. I2C Master Configuration 2 (I2CMCR2) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x038 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RW 0 RW 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset GFPW RO 0 RW 0 reserved Bit/Field Name Type Reset Description 31:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6:4 GFPW RW 0 I2C Glitch Filter Pulse Width This field controls the pulse width select for glitch suppression on the SCL and SDA lines. Glitch suppression values can be programmed relative to system clocks. Value Description 3:0 16.7 reserved RO 0 0x0 Bypass 0x1 1 clock 0x2 2 clocks 0x3 3 clocks 0x4 4 clocks 0x5 8 clocks 0x6 16 clocks 0x7 31 clocks Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Register Descriptions (I2C Slave) The remainder of this section lists and describes the I2C slave registers, in numerical order by address offset. June 12, 2014 997 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 13: I2C Slave Own Address (I2CSOAR), offset 0x800 This register consists of seven address bits that identify the TM4C1231H6PM I2C device on the I2C bus. I2C Slave Own Address (I2CSOAR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x800 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset OAR RO 0 Bit/Field Name Type Reset 31:7 reserved RO 0x0000.00 6:0 OAR RW 0x00 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. I2C Slave Own Address This field specifies bits A6 through A0 of the slave address. 998 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 14: I2C Slave Control/Status (I2CSCSR), offset 0x804 This register functions as a control register when written, and a status register when read. Read-Only Status Register I2C Slave Control/Status (I2CSCSR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x804 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3 OAR2SEL RO 0 RO 0 RO 0 RO 0 RO 0 3 2 1 0 OAR2SEL FBR TREQ RREQ RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. OAR2 Address Matched Value Description 0 Either the address is not matched or the match is in legacy mode. 1 OAR2 address matched and ACKed by the slave. This bit gets reevaluated after every address comparison. 2 FBR RO 0 First Byte Received Value Description 0 The first byte has not been received. 1 The first byte following the slave's own address has been received. This bit is only valid when the RREQ bit is set and is automatically cleared when data has been read from the I2CSDR register. Note: 1 TREQ RO 0 This bit is not used for slave transmit operations. Transmit Request Value Description 0 No outstanding transmit request. 1 The I2C controller has been addressed as a slave transmitter and is using clock stretching to delay the master until data has been written to the I2CSDR register. June 12, 2014 999 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Bit/Field Name Type Reset 0 RREQ RO 0 Description Receive Request Value Description 0 No outstanding receive data. 1 The I2C controller has outstanding receive data from the I2C master and is using clock stretching to delay the master until the data has been read from the I2CSDR register. Write-Only Control Register I2C Slave Control/Status (I2CSCSR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x804 Type WO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 WO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:1 reserved RO 0x0000.000 0 DA WO 0 RO 0 DA Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Device Active Value Description 0 Disables the I2C slave operation. 1 Enables the I2C slave operation. Once this bit has been set, it should not be set again unless it has been cleared by writing a 0 or by a reset, otherwise transfer failures may occur. 1000 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 15: I2C Slave Data (I2CSDR), offset 0x808 Important: This register is read-sensitive. See the register description for details. This register contains the data to be transmitted when in the Slave Transmit state, and the data received when in the Slave Receive state. I2C Slave Data (I2CSDR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x808 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset DATA RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7:0 DATA RW 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Data for Transfer This field contains the data for transfer during a slave receive or transmit operation. June 12, 2014 1001 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 16: I2C Slave Interrupt Mask (I2CSIMR), offset 0x80C This register controls whether a raw interrupt is promoted to a controller interrupt. I2C Slave Interrupt Mask (I2CSIMR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x80C Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 STOPIM STARTIM DATAIM RW 0 RW 0 RW 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 STOPIM RW 0 Stop Condition Interrupt Mask Value Description 1 STARTIM RW 0 0 The STOPRIS interrupt is suppressed and not sent to the interrupt controller. 1 The STOP condition interrupt is sent to the interrupt controller when the STOPRIS bit in the I2CSRIS register is set. Start Condition Interrupt Mask Value Description 0 DATAIM RW 0 0 The STARTRIS interrupt is suppressed and not sent to the interrupt controller. 1 The START condition interrupt is sent to the interrupt controller when the STARTRIS bit in the I2CSRIS register is set. Data Interrupt Mask Value Description 0 The DATARIS interrupt is suppressed and not sent to the interrupt controller. 1 The data received or data requested interrupt is sent to the interrupt controller when the DATARIS bit in the I2CSRIS register is set. 1002 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 17: I2C Slave Raw Interrupt Status (I2CSRIS), offset 0x810 This register specifies whether an interrupt is pending. I2C Slave Raw Interrupt Status (I2CSRIS) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x810 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 STOPRIS STARTRIS DATARIS RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 STOPRIS RO 0 Stop Condition Raw Interrupt Status Value Description 0 No interrupt. 1 A STOP condition interrupt is pending. This bit is cleared by writing a 1 to the STOPIC bit in the I2CSICR register. 1 STARTRIS RO 0 Start Condition Raw Interrupt Status Value Description 0 No interrupt. 1 A START condition interrupt is pending. This bit is cleared by writing a 1 to the STARTIC bit in the I2CSICR register. 0 DATARIS RO 0 Data Raw Interrupt Status Value Description 0 No interrupt. 1 A data received or data requested interrupt is pending. This bit is cleared by writing a 1 to the DATAIC bit in the I2CSICR register. June 12, 2014 1003 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 18: I2C Slave Masked Interrupt Status (I2CSMIS), offset 0x814 This register specifies whether an interrupt was signaled. I2C Slave Masked Interrupt Status (I2CSMIS) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x814 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 STOPMIS STARTMIS DATAMIS RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 STOPMIS RO 0 Stop Condition Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked STOP condition interrupt was signaled is pending. This bit is cleared by writing a 1 to the STOPIC bit in the I2CSICR register. 1 STARTMIS RO 0 Start Condition Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked START condition interrupt was signaled is pending. This bit is cleared by writing a 1 to the STARTIC bit in the I2CSICR register. 0 DATAMIS RO 0 Data Masked Interrupt Status Value Description 0 An interrupt has not occurred or is masked. 1 An unmasked data received or data requested interrupt was signaled is pending. This bit is cleared by writing a 1 to the DATAIC bit in the I2CSICR register. 1004 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 19: I2C Slave Interrupt Clear (I2CSICR), offset 0x818 This register clears the raw interrupt. A read of this register returns no meaningful data. I2C Slave Interrupt Clear (I2CSICR) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x818 Type WO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 STOPIC STARTIC WO 0 WO 0 DATAIC WO 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 STOPIC WO 0 Stop Condition Interrupt Clear Writing a 1 to this bit clears the STOPRIS bit in the I2CSRIS register and the STOPMIS bit in the I2CSMIS register. A read of this register returns no meaningful data. 1 STARTIC WO 0 Start Condition Interrupt Clear Writing a 1 to this bit clears the STARTRIS bit in the I2CSRIS register and the STARTMIS bit in the I2CSMIS register. A read of this register returns no meaningful data. 0 DATAIC WO 0 Data Interrupt Clear Writing a 1 to this bit clears the STOPRIS bit in the I2CSRIS register and the STOPMIS bit in the I2CSMIS register. A read of this register returns no meaningful data. June 12, 2014 1005 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 20: I2C Slave Own Address 2 (I2CSOAR2), offset 0x81C This register consists of seven address bits that identify the alternate address for the I2C device on the I2C bus. I2C Slave Own Address 2 (I2CSOAR2) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x81C Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset OAR2EN RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 OAR2EN RW 0 RW 0 OAR2 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. I2C Slave Own Address 2 Enable Value Description 6:0 OAR2 RW 0x00 0 The alternate address is disabled. 1 Enables the use of the alternate address in the OAR2 field. I2C Slave Own Address 2 This field specifies the alternate OAR2 address. 1006 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 21: I2C Slave ACK Control (I2CSACKCTL), offset 0x820 This register enables the I2C slave to NACK for invalid data or command or ACK for valid data or command. The I2C clock is pulled low after the last data bit until this register is written. I2C Slave ACK Control (I2CSACKCTL) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0x820 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:2 reserved RO 0x0000.000 1 ACKOVAL RW 0 ACKOVAL ACKOEN RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. I2C Slave ACK Override Value Value Description 0 ACKOEN RW 0 0 An ACK is sent indicating valid data or command. 1 A NACK is sent indicating invalid data or command. I2C Slave ACK Override Enable Value Description 16.8 0 A response in not provided. 1 An ACK or NACK is sent according to the value written to the ACKOVAL bit. Register Descriptions (I2C Status and Control) The remainder of this section lists and describes the I2C status and control registers, in numerical order by address offset. June 12, 2014 1007 Texas Instruments-Production Data Inter-Integrated Circuit (I2C) Interface Register 22: I2C Peripheral Properties (I2CPP), offset 0xFC0 The I2CPP register provides information regarding the properties of the I2C module. I2C Peripheral Properties (I2CPP) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0xFC0 Type RO, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset reserved Type Reset RO 0 HS Bit/Field Name Type Reset Description 31:1 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 HS RO 0x1 High-Speed Capable Value Description 0 The interface is capable of Standard, Fast, or Fast mode plus operation. 1 The interface is capable of High-Speed operation. 1008 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 23: I2C Peripheral Configuration (I2CPC), offset 0xFC4 The I2CPC register allows software to enable features present in the I2C module. I2C Peripheral Configuration (I2CPC) I2C 0 base: 0x4002.0000 I2C 1 base: 0x4002.1000 I2C 2 base: 0x4002.2000 I2C 3 base: 0x4002.3000 Offset 0xFC4 Type RO, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 1 reserved Type Reset reserved Type Reset RO 0 HS Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 HS RW 1 High-Speed Capable Value Description 0 The interface is set to Standard, Fast or Fast mode plus operation. 1 The interface is set to High-Speed operation. Note that this encoding may only be used if the HS bit in the I2CPP register is set. Otherwise, this encoding is not available. June 12, 2014 1009 Texas Instruments-Production Data Controller Area Network (CAN) Module 17 Controller Area Network (CAN) Module Controller Area Network (CAN) is a multicast, shared serial bus standard for connecting electronic control units (ECUs). CAN was specifically designed to be robust in electromagnetically-noisy environments and can utilize a differential balanced line like RS-485 or a more robust twisted-pair wire. Originally created for automotive purposes, it is also used in many embedded control applications (such as industrial and medical). Bit rates up to 1 Mbps are possible at network lengths less than 40 meters. Decreased bit rates allow longer network distances (for example, 125 Kbps at 500 meters). The TM4C1231H6PM microcontroller includes one CAN unit with the following features: ■ CAN protocol version 2.0 part A/B ■ Bit rates up to 1 Mbps ■ 32 message objects with individual identifier masks ■ Maskable interrupt ■ Disable Automatic Retransmission mode for Time-Triggered CAN (TTCAN) applications ■ Programmable loopback mode for self-test operation ■ Programmable FIFO mode enables storage of multiple message objects ■ Gluelessly attaches to an external CAN transceiver through the CANnTX and CANnRX signals 1010 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 17.1 Block Diagram Figure 17-1. CAN Controller Block Diagram CAN Control CANCTL CANSTS CANERR CANBIT CANINT CANTST CANBRPE CAN Tx CAN Interface 1 APB Pins APB Interface CANIF1CRQ CANIF1CMSK CANIF1MSK1 CANIF1MSK2 CANIF1ARB1 CANIF1ARB2 CANIF1MCTL CANIF1DA1 CANIF1DA2 CANIF1DB1 CANIF1DB2 CAN Core CAN Rx CAN Interface 2 CANIF2CRQ CANIF2CMSK CANIF2MSK1 CANIF2MSK2 CANIF2ARB1 CANIF2ARB2 CANIF2MCTL CANIF2DA1 CANIF2DA2 CANIF2DB1 CANIF2DB2 Message Object Registers CANTXRQ1 CANTXRQ2 CANNWDA1 CANNWDA2 CANMSG1INT CANMSG2INT CANMSG1VAL CANMSG2VAL Message RAM 32 Message Objects 17.2 Signal Description The following table lists the external signals of the CAN controller and describes the function of each. The CAN controller signals are alternate functions for some GPIO signals and default to be GPIO signals at reset. The column in the table below titled "Pin Mux/Pin Assignment" lists the possible GPIO pin placements for the CAN signals. The AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register (page 636) should be set to choose the CAN controller function. The number in parentheses is the encoding that must be programmed into the PMCn field in the GPIO Port Control (GPIOPCTL) register (page 653) to assign the CAN signal to the specified GPIO port pin. For more information on configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 614. June 12, 2014 1011 Texas Instruments-Production Data Controller Area Network (CAN) Module Table 17-1. Controller Area Network Signals (64LQFP) Pin Name Pin Number Pin Mux / Pin Assignment a Pin Type Buffer Type Description CAN0Rx 28 58 59 PF0 (3) PB4 (8) PE4 (8) I TTL CAN module 0 receive. CAN0Tx 31 57 60 PF3 (3) PB5 (8) PE5 (8) O TTL CAN module 0 transmit. a. The TTL designation indicates the pin has TTL-compatible voltage levels. 17.3 Functional Description The TM4C1231H6PM CAN controller conforms to the CAN protocol version 2.0 (parts A and B). Message transfers that include data, remote, error, and overload frames with an 11-bit identifier (standard) or a 29-bit identifier (extended) are supported. Transfer rates can be programmed up to 1 Mbps. The CAN module consists of three major parts: ■ CAN protocol controller and message handler ■ Message memory ■ CAN register interface A data frame contains data for transmission, whereas a remote frame contains no data and is used to request the transmission of a specific message object. The CAN data/remote frame is constructed as shown in Figure 17-2. Figure 17-2. CAN Data/Remote Frame Remote Transmission Request Start Of Frame Bus Idle R S Control O Message Delimiter T Field R F Number 1 Of Bits 11 or 29 1 6 Delimiter Bits Data Field CRC Sequence A C K EOP IFS 0 . . . 64 15 1 1 1 7 3 CRC Sequence CRC Field Arbitration Field Bit Stuffing End of Frame Field Bus Idle Interframe Field Acknowledgement Field CAN Data Frame 1012 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller The protocol controller transfers and receives the serial data from the CAN bus and passes the data on to the message handler. The message handler then loads this information into the appropriate message object based on the current filtering and identifiers in the message object memory. The message handler is also responsible for generating interrupts based on events on the CAN bus. The message object memory is a set of 32 identical memory blocks that hold the current configuration, status, and actual data for each message object. These memory blocks are accessed via either of the CAN message object register interfaces. The message memory is not directly accessible in the TM4C1231H6PM memory map, so the TM4C1231H6PM CAN controller provides an interface to communicate with the message memory via two CAN interface register sets for communicating with the message objects. These two interfaces must be used to read or write to each message object. The two message object interfaces allow parallel access to the CAN controller message objects when multiple objects may have new information that must be processed. In general, one interface is used for transmit data and one for receive data. 17.3.1 Initialization To use the CAN controller, the peripheral clock must be enabled using the RCGC0 register (see page 425). In addition, the clock to the appropriate GPIO module must be enabled via the RCGC2 register (see page 431). To find out which GPIO port to enable, refer to Table 20-4 on page 1087. Set the GPIO AFSEL bits for the appropriate pins (see page 636). Configure the PMCn fields in the GPIOPCTL register to assign the CAN signals to the appropriate pins. See page 653 and Table 20-5 on page 1091. Software initialization is started by setting the INIT bit in the CAN Control (CANCTL) register (with software or by a hardware reset) or by going bus-off, which occurs when the transmitter's error counter exceeds a count of 255. While INIT is set, all message transfers to and from the CAN bus are stopped and the CANnTX signal is held High. Entering the initialization state does not change the configuration of the CAN controller, the message objects, or the error counters. However, some configuration registers are only accessible while in the initialization state. To initialize the CAN controller, set the CAN Bit Timing (CANBIT) register and configure each message object. If a message object is not needed, label it as not valid by clearing the MSGVAL bit in the CAN IFn Arbitration 2 (CANIFnARB2) register. Otherwise, the whole message object must be initialized, as the fields of the message object may not have valid information, causing unexpected results. Both the INIT and CCE bits in the CANCTL register must be set in order to access the CANBIT register and the CAN Baud Rate Prescaler Extension (CANBRPE) register to configure the bit timing. To leave the initialization state, the INIT bit must be cleared. Afterwards, the internal Bit Stream Processor (BSP) synchronizes itself to the data transfer on the CAN bus by waiting for the occurrence of a sequence of 11 consecutive recessive bits (indicating a bus idle condition) before it takes part in bus activities and starts message transfers. Message object initialization does not require the CAN to be in the initialization state and can be done on the fly. However, message objects should all be configured to particular identifiers or set to not valid before message transfer starts. To change the configuration of a message object during normal operation, clear the MSGVAL bit in the CANIFnARB2 register to indicate that the message object is not valid during the change. When the configuration is completed, set the MSGVAL bit again to indicate that the message object is once again valid. 17.3.2 Operation Two sets of CAN Interface Registers (CANIF1x and CANIF2x) are used to access the message objects in the Message RAM. The CAN controller coordinates transfers to and from the Message RAM to and from the registers. The two sets are independent and identical and can be used to June 12, 2014 1013 Texas Instruments-Production Data Controller Area Network (CAN) Module queue transactions. Generally, one interface is used to transmit data and one is used to receive data. Once the CAN module is initialized and the INIT bit in the CANCTL register is cleared, the CAN module synchronizes itself to the CAN bus and starts the message transfer. As each message is received, it goes through the message handler's filtering process, and if it passes through the filter, is stored in the message object specified by the MNUM bit in the CAN IFn Command Request (CANIFnCRQ) register. The whole message (including all arbitration bits, data-length code, and eight data bytes) is stored in the message object. If the Identifier Mask (the MSK bits in the CAN IFn Mask 1 and CAN IFn Mask 2 (CANIFnMSKn) registers) is used, the arbitration bits that are masked to "don't care" may be overwritten in the message object. The CPU may read or write each message at any time via the CAN Interface Registers. The message handler guarantees data consistency in case of concurrent accesses. The transmission of message objects is under the control of the software that is managing the CAN hardware. Message objects can be used for one-time data transfers or can be permanent message objects used to respond in a more periodic manner. Permanent message objects have all arbitration and control set up, and only the data bytes are updated. At the start of transmission, the appropriate TXRQST bit in the CAN Transmission Request n (CANTXRQn) register and the NEWDAT bit in the CAN New Data n (CANNWDAn) register are set. If several transmit messages are assigned to the same message object (when the number of message objects is not sufficient), the whole message object has to be configured before the transmission of this message is requested. The transmission of any number of message objects may be requested at the same time; they are transmitted according to their internal priority, which is based on the message identifier (MNUM) for the message object, with 1 being the highest priority and 32 being the lowest priority. Messages may be updated or set to not valid any time, even when their requested transmission is still pending. The old data is discarded when a message is updated before its pending transmission has started. Depending on the configuration of the message object, the transmission of a message may be requested autonomously by the reception of a remote frame with a matching identifier. Transmission can be automatically started by the reception of a matching remote frame. To enable this mode, set the RMTEN bit in the CAN IFn Message Control (CANIFnMCTL) register. A matching received remote frame causes the TXRQST bit to be set, and the message object automatically transfers its data or generates an interrupt indicating a remote frame was requested. A remote frame can be strictly a single message identifier, or it can be a range of values specified in the message object. The CAN mask registers, CANIFnMSKn, configure which groups of frames are identified as remote frame requests. The UMASK bit in the CANIFnMCTL register enables the MSK bits in the CANIFnMSKn register to filter which frames are identified as a remote frame request. The MXTD bit in the CANIFnMSK2 register should be set if a remote frame request is expected to be triggered by 29-bit extended identifiers. 17.3.3 Transmitting Message Objects If the internal transmit shift register of the CAN module is ready for loading, and if a data transfer is not occurring between the CAN Interface Registers and message RAM, the valid message object with the highest priority that has a pending transmission request is loaded into the transmit shift register by the message handler and the transmission is started. The message object's NEWDAT bit in the CANNWDAn register is cleared. After a successful transmission, and if no new data was written to the message object since the start of the transmission, the TXRQST bit in the CANTXRQn register is cleared. If the CAN controller is configured to interrupt on a successful transmission of a message object, (the TXIE bit in the CAN IFn Message Control (CANIFnMCTL) register is set), the INTPND bit in the CANIFnMCTL register is set after a successful transmission. If the CAN module has lost the arbitration or if an error occurred during the transmission, the message is 1014 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller re-transmitted as soon as the CAN bus is free again. If, meanwhile, the transmission of a message with higher priority has been requested, the messages are transmitted in the order of their priority. 17.3.4 Configuring a Transmit Message Object The following steps illustrate how to configure a transmit message object. 1. In the CAN IFn Command Mask (CANIFnCMASK) register: ■ Set the WRNRD bit to specify a write to the CANIFnCMASK register; specify whether to transfer the IDMASK, DIR, and MXTD of the message object into the CAN IFn registers using the MASK bit ■ Specify whether to transfer the ID, DIR, XTD, and MSGVAL of the message object into the interface registers using the ARB bit ■ Specify whether to transfer the control bits into the interface registers using the CONTROL bit ■ Specify whether to clear the INTPND bit in the CANIFnMCTL register using the CLRINTPND bit ■ Specify whether to clear the NEWDAT bit in the CANNWDAn register using the NEWDAT bit ■ Specify which bits to transfer using the DATAA and DATAB bits 2. In the CANIFnMSK1 register, use the MSK[15:0] bits to specify which of the bits in the 29-bit or 11-bit message identifier are used for acceptance filtering. Note that MSK[15:0] in this register are used for bits [15:0] of the 29-bit message identifier and are not used for an 11-bit identifier. A value of 0x00 enables all messages to pass through the acceptance filtering. Also note that in order for these bits to be used for acceptance filtering, they must be enabled by setting the UMASK bit in the CANIFnMCTL register. 3. In the CANIFnMSK2 register, use the MSK[12:0] bits to specify which of the bits in the 29-bit or 11-bit message identifier are used for acceptance filtering. Note that MSK[12:0] are used for bits [28:16] of the 29-bit message identifier; whereas MSK[12:2] are used for bits [10:0] of the 11-bit message identifier. Use the MXTD and MDIR bits to specify whether to use XTD and DIR for acceptance filtering. A value of 0x00 enables all messages to pass through the acceptance filtering. Also note that in order for these bits to be used for acceptance filtering, they must be enabled by setting the UMASK bit in the CANIFnMCTL register. 4. For a 29-bit identifier, configure ID[15:0] in the CANIFnARB1 register for bits [15:0] of the message identifier and ID[12:0] in the CANIFnARB2 register for bits [28:16] of the message identifier. Set the XTD bit to indicate an extended identifier; set the DIR bit to indicate transmit; and set the MSGVAL bit to indicate that the message object is valid. 5. For an 11-bit identifier, disregard the CANIFnARB1 register and configure ID[12:2] in the CANIFnARB2 register for bits [10:0] of the message identifier. Clear the XTD bit to indicate a standard identifier; set the DIR bit to indicate transmit; and set the MSGVAL bit to indicate that the message object is valid. 6. In the CANIFnMCTL register: June 12, 2014 1015 Texas Instruments-Production Data Controller Area Network (CAN) Module ■ Optionally set the UMASK bit to enable the mask (MSK, MXTD, and MDIR specified in the CANIFnMSK1 and CANIFnMSK2 registers) for acceptance filtering ■ Optionally set the TXIE bit to enable the INTPND bit to be set after a successful transmission ■ Optionally set the RMTEN bit to enable the TXRQST bit to be set on the reception of a matching remote frame allowing automatic transmission ■ Set the EOB bit for a single message object ■ Configure the DLC[3:0] field to specify the size of the data frame. Take care during this configuration not to set the NEWDAT, MSGLST, INTPND or TXRQST bits. 7. Load the data to be transmitted into the CAN IFn Data (CANIFnDA1, CANIFnDA2, CANIFnDB1, CANIFnDB2) registers. Byte 0 of the CAN data frame is stored in DATA[7:0] in the CANIFnDA1 register. 8. Program the number of the message object to be transmitted in the MNUM field in the CAN IFn Command Request (CANIFnCRQ) register. 9. When everything is properly configured, set the TXRQST bit in the CANIFnMCTL register. Once this bit is set, the message object is available to be transmitted, depending on priority and bus availability. Note that setting the RMTEN bit in the CANIFnMCTL register can also start message transmission if a matching remote frame has been received. 17.3.5 Updating a Transmit Message Object The CPU may update the data bytes of a Transmit Message Object any time via the CAN Interface Registers and neither the MSGVAL bit in the CANIFnARB2 register nor the TXRQST bits in the CANIFnMCTL register have to be cleared before the update. Even if only some of the data bytes are to be updated, all four bytes of the corresponding CANIFnDAn/CANIFnDBn register have to be valid before the content of that register is transferred to the message object. Either the CPU must write all four bytes into the CANIFnDAn/CANIFnDBn register or the message object is transferred to the CANIFnDAn/CANIFnDBn register before the CPU writes the new data bytes. In order to only update the data in a message object, the WRNRD, DATAA and DATAB bits in the CANIFnMSKn register are set, followed by writing the updated data into CANIFnDA1, CANIFnDA2, CANIFnDB1, and CANIFnDB2 registers, and then the number of the message object is written to the MNUM field in the CAN IFn Command Request (CANIFnCRQ) register. To begin transmission of the new data as soon as possible, set the TXRQST bit in the CANIFnMSKn register. To prevent the clearing of the TXRQST bit in the CANIFnMCTL register at the end of a transmission that may already be in progress while the data is updated, the NEWDAT and TXRQST bits have to be set at the same time in the CANIFnMCTL register. When these bits are set at the same time, NEWDAT is cleared as soon as the new transmission has started. 17.3.6 Accepting Received Message Objects When the arbitration and control field (the ID and XTD bits in the CANIFnARB2 and the RMTEN and DLC[3:0] bits of the CANIFnMCTL register) of an incoming message is completely shifted into the CAN controller, the message handling capability of the controller starts scanning the message RAM for a matching valid message object. To scan the message RAM for a matching message object, the controller uses the acceptance filtering programmed through the mask bits in the CANIFnMSKn register and enabled using the UMASK bit in the CANIFnMCTL register. Each valid 1016 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller message object, starting with object 1, is compared with the incoming message to locate a matching message object in the message RAM. If a match occurs, the scanning is stopped and the message handler proceeds depending on whether it is a data frame or remote frame that was received. 17.3.7 Receiving a Data Frame The message handler stores the message from the CAN controller receive shift register into the matching message object in the message RAM. The data bytes, all arbitration bits, and the DLC bits are all stored into the corresponding message object. In this manner, the data bytes are connected with the identifier even if arbitration masks are used. The NEWDAT bit of the CANIFnMCTL register is set to indicate that new data has been received. The CPU should clear this bit when it reads the message object to indicate to the controller that the message has been received, and the buffer is free to receive more messages. If the CAN controller receives a message and the NEWDAT bit is already set, the MSGLST bit in the CANIFnMCTL register is set to indicate that the previous data was lost. If the system requires an interrupt on successful reception of a frame, the RXIE bit of the CANIFnMCTL register should be set. In this case, the INTPND bit of the same register is set, causing the CANINT register to point to the message object that just received a message. The TXRQST bit of this message object should be cleared to prevent the transmission of a remote frame. 17.3.8 Receiving a Remote Frame A remote frame contains no data, but instead specifies which object should be transmitted. When a remote frame is received, three different configurations of the matching message object have to be considered: Table 17-2. Message Object Configurations Configuration in CANIFnMCTL ■ Description ■ DIR = 1 (direction = transmit); programmed in the At the reception of a matching remote frame, the TXRQST bit of this CANIFnARB2 register message object is set. The rest of the message object remains unchanged, and the controller automatically transfers the data in RMTEN = 1 (set the TXRQST bit of the the message object as soon as possible. CANIFnMCTL register at reception of the frame to enable transmission) ■ UMASK = 1 or 0 ■ DIR = 1 (direction = transmit); programmed in the At the reception of a matching remote frame, the TXRQST bit of this CANIFnARB2 register message object remains unchanged, and the remote frame is ignored. This remote frame is disabled, the data is not transferred RMTEN = 0 (do not change the TXRQST bit of the and nothing indicates that the remote frame ever happened. CANIFnMCTL register at reception of the frame) ■ ■ UMASK = 0 (ignore mask in the CANIFnMSKn register) ■ DIR = 1 (direction = transmit); programmed in the At the reception of a matching remote frame, the TXRQST bit of this CANIFnARB2 register message object is cleared. The arbitration and control field (ID + XTD + RMTEN + DLC) from the shift register is stored into the message RMTEN = 0 (do not change the TXRQST bit of the object in the message RAM, and the NEWDAT bit of this message CANIFnMCTL register at reception of the frame) object is set. The data field of the message object remains unchanged; the remote frame is treated similar to a received data UMASK = 1 (use mask (MSK, MXTD, and MDIR in frame. This mode is useful for a remote data request from another the CANIFnMSKn register) for acceptance filtering) CAN device for which the TM4C1231H6PM controller does not have readily available data. The software must fill the data and answer the frame manually. ■ ■ June 12, 2014 1017 Texas Instruments-Production Data Controller Area Network (CAN) Module 17.3.9 Receive/Transmit Priority The receive/transmit priority for the message objects is controlled by the message number. Message object 1 has the highest priority, while message object 32 has the lowest priority. If more than one transmission request is pending, the message objects are transmitted in order based on the message object with the lowest message number. This prioritization is separate from that of the message identifier which is enforced by the CAN bus. As a result, if message object 1 and message object 2 both have valid messages to be transmitted, message object 1 is always transmitted first regardless of the message identifier in the message object itself. 17.3.10 Configuring a Receive Message Object The following steps illustrate how to configure a receive message object. 1. Program the CAN IFn Command Mask (CANIFnCMASK) register as described in the “Configuring a Transmit Message Object” on page 1015 section, except that the WRNRD bit is set to specify a write to the message RAM. 2. Program the CANIFnMSK1and CANIFnMSK2 registers as described in the “Configuring a Transmit Message Object” on page 1015 section to configure which bits are used for acceptance filtering. Note that in order for these bits to be used for acceptance filtering, they must be enabled by setting the UMASK bit in the CANIFnMCTL register. 3. In the CANIFnMSK2 register, use the MSK[12:0] bits to specify which of the bits in the 29-bit or 11-bit message identifier are used for acceptance filtering. Note that MSK[12:0] are used for bits [28:16] of the 29-bit message identifier; whereas MSK[12:2] are used for bits [10:0] of the 11-bit message identifier. Use the MXTD and MDIR bits to specify whether to use XTD and DIR for acceptance filtering. A value of 0x00 enables all messages to pass through the acceptance filtering. Also note that in order for these bits to be used for acceptance filtering, they must be enabled by setting the UMASK bit in the CANIFnMCTL register. 4. Program the CANIFnARB1 and CANIFnARB2 registers as described in the “Configuring a Transmit Message Object” on page 1015 section to program XTD and ID bits for the message identifier to be received; set the MSGVAL bit to indicate a valid message; and clear the DIR bit to specify receive. 5. In the CANIFnMCTL register: ■ Optionally set the UMASK bit to enable the mask (MSK, MXTD, and MDIR specified in the CANIFnMSK1 and CANIFnMSK2 registers) for acceptance filtering ■ Optionally set the RXIE bit to enable the INTPND bit to be set after a successful reception ■ Clear the RMTEN bit to leave the TXRQST bit unchanged ■ Set the EOB bit for a single message object ■ Configure the DLC[3:0] field to specify the size of the data frame Take care during this configuration not to set the NEWDAT, MSGLST, INTPND or TXRQST bits. 6. Program the number of the message object to be received in the MNUM field in the CAN IFn Command Request (CANIFnCRQ) register. Reception of the message object begins as soon as a matching frame is available on the CAN bus. 1018 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller When the message handler stores a data frame in the message object, it stores the received Data Length Code and eight data bytes in the CANIFnDA1, CANIFnDA2, CANIFnDB1, and CANIFnDB2 register. Byte 0 of the CAN data frame is stored in DATA[7:0] in the CANIFnDA1 register. If the Data Length Code is less than 8, the remaining bytes of the message object are overwritten by unspecified values. The CAN mask registers can be used to allow groups of data frames to be received by a message object. The CAN mask registers, CANIFnMSKn, configure which groups of frames are received by a message object. The UMASK bit in the CANIFnMCTL register enables the MSK bits in the CANIFnMSKn register to filter which frames are received. The MXTD bit in the CANIFnMSK2 register should be set if only 29-bit extended identifiers are expected by this message object. 17.3.11 Handling of Received Message Objects The CPU may read a received message any time via the CAN Interface registers because the data consistency is guaranteed by the message handler state machine. Typically, the CPU first writes 0x007F to the CANIFnCMSK register and then writes the number of the message object to the CANIFnCRQ register. That combination transfers the whole received message from the message RAM into the Message Buffer registers (CANIFnMSKn, CANIFnARBn, and CANIFnMCTL). Additionally, the NEWDAT and INTPND bits are cleared in the message RAM, acknowledging that the message has been read and clearing the pending interrupt generated by this message object. If the message object uses masks for acceptance filtering, the CANIFnARBn registers show the full, unmasked ID for the received message. The NEWDAT bit in the CANIFnMCTL register shows whether a new message has been received since the last time this message object was read. The MSGLST bit in the CANIFnMCTL register shows whether more than one message has been received since the last time this message object was read. MSGLST is not automatically cleared, and should be cleared by software after reading its status. Using a remote frame, the CPU may request new data from another CAN node on the CAN bus. Setting the TXRQST bit of a receive object causes the transmission of a remote frame with the receive object's identifier. This remote frame triggers the other CAN node to start the transmission of the matching data frame. If the matching data frame is received before the remote frame could be transmitted, the TXRQST bit is automatically reset. This prevents the possible loss of data when the other device on the CAN bus has already transmitted the data slightly earlier than expected. 17.3.11.1 Configuration of a FIFO Buffer With the exception of the EOB bit in the CANIFnMCTL register, the configuration of receive message objects belonging to a FIFO buffer is the same as the configuration of a single receive message object (see “Configuring a Receive Message Object” on page 1018). To concatenate two or more message objects into a FIFO buffer, the identifiers and masks (if used) of these message objects have to be programmed to matching values. Due to the implicit priority of the message objects, the message object with the lowest message object number is the first message object in a FIFO buffer. The EOB bit of all message objects of a FIFO buffer except the last one must be cleared. The EOB bit of the last message object of a FIFO buffer is set, indicating it is the last entry in the buffer. 17.3.11.2 Reception of Messages with FIFO Buffers Received messages with identifiers matching to a FIFO buffer are stored starting with the message object with the lowest message number. When a message is stored into a message object of a FIFO buffer, the NEWDAT of the CANIFnMCTL register bit of this message object is set. By setting June 12, 2014 1019 Texas Instruments-Production Data Controller Area Network (CAN) Module NEWDAT while EOB is clear, the message object is locked and cannot be written to by the message handler until the CPU has cleared the NEWDAT bit. Messages are stored into a FIFO buffer until the last message object of this FIFO buffer is reached. Until all of the preceding message objects have been released by clearing the NEWDAT bit, all further messages for this FIFO buffer are written into the last message object of the FIFO buffer and therefore overwrite previous messages. 17.3.11.3 Reading from a FIFO Buffer When the CPU transfers the contents of a message object from a FIFO buffer by writing its number to the CANIFnCRQ register, the TXRQST and CLRINTPND bits in the CANIFnCMSK register should be set such that the NEWDAT and INTPEND bits in the CANIFnMCTL register are cleared after the read. The values of these bits in the CANIFnMCTL register always reflect the status of the message object before the bits are cleared. To assure the correct function of a FIFO buffer, the CPU should read out the message objects starting with the message object with the lowest message number. When reading from the FIFO buffer, the user should be aware that a new received message is placed in the message object with the lowest message number for which the NEWDAT bit of the CANIFnMCTL register is clear. As a result, the order of the received messages in the FIFO is not guaranteed. Figure 17-3 on page 1021 shows how a set of message objects which are concatenated to a FIFO Buffer can be handled by the CPU. 1020 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 17-3. Message Objects in a FIFO Buffer START Message Interrupt Read Interrupt Pointer 0x0000 Case Interrupt Pointer else 0x8000 END Status Change Interrupt Handling MNUM = Interrupt Pointer Write MNUM to IFn Command Request (Read Message to IFn Registers, Reset NEWDAT = 0, Reset INTPND = 0 Read IFn Message Control Yes No NEWDAT = 1 Read Data from IFn Data A,B EOB = 1 Yes No MNUM = MNUM + 1 17.3.12 Handling of Interrupts If several interrupts are pending, the CAN Interrupt (CANINT) register points to the pending interrupt with the highest priority, disregarding their chronological order. The status interrupt has the highest June 12, 2014 1021 Texas Instruments-Production Data Controller Area Network (CAN) Module priority. Among the message interrupts, the message object's interrupt with the lowest message number has the highest priority. A message interrupt is cleared by clearing the message object's INTPND bit in the CANIFnMCTL register or by reading the CAN Status (CANSTS) register. The status Interrupt is cleared by reading the CANSTS register. The interrupt identifier INTID in the CANINT register indicates the cause of the interrupt. When no interrupt is pending, the register reads as 0x0000. If the value of the INTID field is different from 0, then an interrupt is pending. If the IE bit is set in the CANCTL register, the interrupt line to the interrupt controller is active. The interrupt line remains active until the INTID field is 0, meaning that all interrupt sources have been cleared (the cause of the interrupt is reset), or until IE is cleared, which disables interrupts from the CAN controller. The INTID field of the CANINT register points to the pending message interrupt with the highest interrupt priority. The SIE bit in the CANCTL register controls whether a change of the RXOK, TXOK, and LEC bits in the CANSTS register can cause an interrupt. The EIE bit in the CANCTLregister controls whether a change of the BOFF and EWARN bits in the CANSTS register can cause an interrupt. The IE bit in the CANCTL register controls whether any interrupt from the CAN controller actually generates an interrupt to the interrupt controller. The CANINT register is updated even when the IE bit in the CANCTL register is clear, but the interrupt is not indicated to the CPU. A value of 0x8000 in the CANINT register indicates that an interrupt is pending because the CAN module has updated, but not necessarily changed, the CANSTS register, indicating that either an error or status interrupt has been generated. A write access to the CANSTS register can clear the RXOK, TXOK, and LEC bits in that same register; however, the only way to clear the source of a status interrupt is to read the CANSTS register. The source of an interrupt can be determined in two ways during interrupt handling. The first is to read the INTID bit in the CANINT register to determine the highest priority interrupt that is pending, and the second is to read the CAN Message Interrupt Pending (CANMSGnINT) register to see all of the message objects that have pending interrupts. An interrupt service routine reading the message that is the source of the interrupt may read the message and clear the message object's INTPND bit at the same time by setting the CLRINTPND bit in the CANIFnCMSK register. Once the INTPND bit has been cleared, the CANINT register contains the message number for the next message object with a pending interrupt. 17.3.13 Test Mode A Test Mode is provided which allows various diagnostics to be performed. Test Mode is entered by setting the TEST bit in the CANCTL register. Once in Test Mode, the TX[1:0], LBACK, SILENT and BASIC bits in the CAN Test (CANTST) register can be used to put the CAN controller into the various diagnostic modes. The RX bit in the CANTST register allows monitoring of the CANnRX signal. All CANTST register functions are disabled when the TEST bit is cleared. 17.3.13.1 Silent Mode Silent Mode can be used to analyze the traffic on a CAN bus without affecting it by the transmission of dominant bits (Acknowledge Bits, Error Frames). The CAN Controller is put in Silent Mode setting the SILENT bit in the CANTST register. In Silent Mode, the CAN controller is able to receive valid data frames and valid remote frames, but it sends only recessive bits on the CAN bus and cannot start a transmission. If the CAN Controller is required to send a dominant bit (ACK bit, overload flag, or active error flag), the bit is rerouted internally so that the CAN Controller monitors this dominant bit, although the CAN bus remains in recessive state. 1022 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 17.3.13.2 Loopback Mode Loopback mode is useful for self-test functions. In Loopback Mode, the CAN Controller internally routes the CANnTX signal on to the CANnRX signal and treats its own transmitted messages as received messages and stores them (if they pass acceptance filtering) into the message buffer. The CAN Controller is put in Loopback Mode by setting the LBACK bit in the CANTST register. To be independent from external stimulation, the CAN Controller ignores acknowledge errors (a recessive bit sampled in the acknowledge slot of a data/remote frame) in Loopback Mode. The actual value of the CANnRX signal is disregarded by the CAN Controller. The transmitted messages can be monitored on the CANnTX signal. 17.3.13.3 Loopback Combined with Silent Mode Loopback Mode and Silent Mode can be combined to allow the CAN Controller to be tested without affecting a running CAN system connected to the CANnTX and CANnRX signals. In this mode, the CANnRX signal is disconnected from the CAN Controller and the CANnTX signal is held recessive. This mode is enabled by setting both the LBACK and SILENT bits in the CANTST register. 17.3.13.4 Basic Mode Basic Mode allows the CAN Controller to be operated without the Message RAM. In Basic Mode, The CANIF1 registers are used as the transmit buffer. The transmission of the contents of the IF1 registers is requested by setting the BUSY bit of the CANIF1CRQ register. The CANIF1 registers are locked while the BUSY bit is set. The BUSY bit indicates that a transmission is pending. As soon the CAN bus is idle, the CANIF1 registers are loaded into the shift register of the CAN Controller and transmission is started. When the transmission has completed, the BUSY bit is cleared and the locked CANIF1 registers are released. A pending transmission can be aborted at any time by clearing the BUSY bit in the CANIF1CRQ register while the CANIF1 registers are locked. If the CPU has cleared the BUSY bit, a possible retransmission in case of lost arbitration or an error is disabled. The CANIF2 Registers are used as a receive buffer. After the reception of a message, the contents of the shift register are stored in the CANIF2 registers, without any acceptance filtering. Additionally, the actual contents of the shift register can be monitored during the message transfer. Each time a read message object is initiated by setting the BUSY bit of the CANIF2CRQ register, the contents of the shift register are stored into the CANIF2 registers. In Basic Mode, all message-object-related control and status bits and of the control bits of the CANIFnCMSK registers are not evaluated. The message number of the CANIFnCRQ registers is also not evaluated. In the CANIF2MCTL register, the NEWDAT and MSGLST bits retain their function, the DLC[3:0] field shows the received DLC, the other control bits are cleared. Basic Mode is enabled by setting the BASIC bit in the CANTST register. 17.3.13.5 Transmit Control Software can directly override control of the CANnTX signal in four different ways. ■ CANnTX is controlled by the CAN Controller ■ The sample point is driven on the CANnTX signal to monitor the bit timing ■ CANnTX drives a low value ■ CANnTX drives a high value June 12, 2014 1023 Texas Instruments-Production Data Controller Area Network (CAN) Module The last two functions, combined with the readable CAN receive pin CANnRX, can be used to check the physical layer of the CAN bus. The Transmit Control function is enabled by programming the TX[1:0] field in the CANTST register. The three test functions for the CANnTX signal interfere with all CAN protocol functions. TX[1:0] must be cleared when CAN message transfer or Loopback Mode, Silent Mode, or Basic Mode are selected. 17.3.14 Bit Timing Configuration Error Considerations Even if minor errors in the configuration of the CAN bit timing do not result in immediate failure, the performance of a CAN network can be reduced significantly. In many cases, the CAN bit synchronization amends a faulty configuration of the CAN bit timing to such a degree that only occasionally an error frame is generated. In the case of arbitration, however, when two or more CAN nodes simultaneously try to transmit a frame, a misplaced sample point may cause one of the transmitters to become error passive. The analysis of such sporadic errors requires a detailed knowledge of the CAN bit synchronization inside a CAN node and of the CAN nodes' interaction on the CAN bus. 17.3.15 Bit Time and Bit Rate The CAN system supports bit rates in the range of lower than 1 Kbps up to 1000 Kbps. Each member of the CAN network has its own clock generator. The timing parameter of the bit time can be configured individually for each CAN node, creating a common bit rate even though the CAN nodes' oscillator periods may be different. Because of small variations in frequency caused by changes in temperature or voltage and by deteriorating components, these oscillators are not absolutely stable. As long as the variations remain inside a specific oscillator's tolerance range, the CAN nodes are able to compensate for the different bit rates by periodically resynchronizing to the bit stream. According to the CAN specification, the bit time is divided into four segments (see Figure 17-4 on page 1025): the Synchronization Segment, the Propagation Time Segment, the Phase Buffer Segment 1, and the Phase Buffer Segment 2. Each segment consists of a specific, programmable number of time quanta (see Table 17-3 on page 1025). The length of the time quantum (tq), which is the basic time unit of the bit time, is defined by the CAN controller's input clock (fsys) and the Baud Rate Prescaler (BRP): tq = BRP / fsys The fsys input clock is the system clock frequency as configured by the RCC or RCC2 registers (see page 241 or page 247). The Synchronization Segment Sync is that part of the bit time where edges of the CAN bus level are expected to occur; the distance between an edge that occurs outside of Sync and the Sync is called the phase error of that edge. The Propagation Time Segment Prop is intended to compensate for the physical delay times within the CAN network. The Phase Buffer Segments Phase1 and Phase2 surround the Sample Point. The (Re-)Synchronization Jump Width (SJW) defines how far a resynchronization may move the Sample Point inside the limits defined by the Phase Buffer Segments to compensate for edge phase errors. A given bit rate may be met by different bit-time configurations, but for the proper function of the CAN network, the physical delay times and the oscillator's tolerance range have to be considered. 1024 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 17-4. CAN Bit Time Nominal CAN Bit Time a b TSEG1 Sync Prop TSEG2 Phase1 c 1 Time Quantum q) (tq Phase2 Sample Point a. TSEG1 = Prop + Phase1 b. TSEG2 = Phase2 c. Phase1 = Phase2 or Phase1 + 1 = Phase2 a Table 17-3. CAN Protocol Ranges Parameter Range Remark BRP [1 .. 64] Defines the length of the time quantum tq. The CANBRPE register can be used to extend the range to 1024. Sync 1 tq Fixed length, synchronization of bus input to system clock Prop [1 .. 8] tq Compensates for the physical delay times Phase1 [1 .. 8] tq May be lengthened temporarily by synchronization Phase2 [1 .. 8] tq May be shortened temporarily by synchronization SJW [1 .. 4] tq May not be longer than either Phase Buffer Segment a. This table describes the minimum programmable ranges required by the CAN protocol. The bit timing configuration is programmed in two register bytes in the CANBIT register. In the CANBIT register, the four components TSEG2, TSEG1, SJW, and BRP have to be programmed to a numerical value that is one less than its functional value; so instead of values in the range of [1..n], values in the range of [0..n-1] are programmed. That way, for example, SJW (functional range of [1..4]) is represented by only two bits in the SJW bit field. Table 17-4 shows the relationship between the CANBIT register values and the parameters. Table 17-4. CANBIT Register Values CANBIT Register Field Setting TSEG2 Phase2 - 1 TSEG1 Prop + Phase1 - 1 SJW SJW - 1 BRP BRP Therefore, the length of the bit time is (programmed values): [TSEG1 + TSEG2 + 3] × tq or (functional values): [Sync + Prop + Phase1 + Phase2] × tq The data in the CANBIT register is the configuration input of the CAN protocol controller. The baud rate prescaler (configured by the BRP field) defines the length of the time quantum, the basic time June 12, 2014 1025 Texas Instruments-Production Data Controller Area Network (CAN) Module unit of the bit time; the bit timing logic (configured by TSEG1, TSEG2, and SJW) defines the number of time quanta in the bit time. The processing of the bit time, the calculation of the position of the sample point, and occasional synchronizations are controlled by the CAN controller and are evaluated once per time quantum. The CAN controller translates messages to and from frames. In addition, the controller generates and discards the enclosing fixed format bits, inserts and extracts stuff bits, calculates and checks the CRC code, performs the error management, and decides which type of synchronization is to be used. The bit value is received or transmitted at the sample point. The information processing time (IPT) is the time after the sample point needed to calculate the next bit to be transmitted on the CAN bus. The IPT includes any of the following: retrieving the next data bit, handling a CRC bit, determining if bit stuffing is required, generating an error flag or simply going idle. The IPT is application-specific but may not be longer than 2 tq; the CAN's IPT is 0 tq. Its length is the lower limit of the programmed length of Phase2. In case of synchronization, Phase2 may be shortened to a value less than IPT, which does not affect bus timing. 17.3.16 Calculating the Bit Timing Parameters Usually, the calculation of the bit timing configuration starts with a required bit rate or bit time. The resulting bit time (1/bit rate) must be an integer multiple of the system clock period. The bit time may consist of 4 to 25 time quanta. Several combinations may lead to the required bit time, allowing iterations of the following steps. The first part of the bit time to be defined is Prop. Its length depends on the delay times measured in the system. A maximum bus length as well as a maximum node delay has to be defined for expandable CAN bus systems. The resulting time for Prop is converted into time quanta (rounded up to the nearest integer multiple of tq). Sync is 1 tq long (fixed), which leaves (bit time - Prop - 1) tq for the two Phase Buffer Segments. If the number of remaining tq is even, the Phase Buffer Segments have the same length, that is, Phase2 = Phase1, else Phase2 = Phase1 + 1. The minimum nominal length of Phase2 has to be regarded as well. Phase2 may not be shorter than the CAN controller's Information Processing Time, which is, depending on the actual implementation, in the range of [0..2] tq. The length of the synchronization jump width is set to the least of 4, Phase1 or Phase2. The oscillator tolerance range necessary for the resulting configuration is calculated by the formula given below: (1 − df ) × fnom ≤ fosc ≤ (1 + df ) × fnom where: df ≤ (Phase _ seg1, Phase _ seg2) min 2 × (13 × tbit − Phase _ Seg 2) ■ df = Maximum tolerance of oscillator frequency ■ fosc Actual=oscillator df =max 2 × dffrequency × fnom ■ fnom = Nominal oscillator frequency Maximum frequency tolerance must take into account the following formulas: 1026 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller − )df × fnom ≤ fosc + )df × fnom (1 −(1df × )fnom ≤ fosc ≤ (1≤ +(1df × )fnom (Phase _ seg 1, Phase _ seg 2) min (Phase _ seg 1, Phase _ seg 2) min df df ≤ ≤ 2 × (13 × tbit − Phase _ Seg 2) 2 × (13 × tbit − Phase _ Seg 2) × df × fnom df df maxmax = 2=× 2df × fnom where: ■ Phase1 and Phase2 are from Table 17-3 on page 1025 ■ tbit = Bit Time ■ dfmax = Maximum difference between two oscillators If more than one configuration is possible, that configuration allowing the highest oscillator tolerance range should be chosen. CAN nodes with different system clocks require different configurations to come to the same bit rate. The calculation of the propagation time in the CAN network, based on the nodes with the longest delay times, is done once for the whole network. The CAN system's oscillator tolerance range is limited by the node with the lowest tolerance range. The calculation may show that bus length or bit rate have to be decreased or that the oscillator frequencies' stability has to be increased in order to find a protocol-compliant configuration of the CAN bit timing. 17.3.16.1 Example for Bit Timing at High Baud Rate In this example, the frequency of CAN clock is 25 MHz, and the bit rate is 1 Mbps. bit time = 1 µs = n * tq = 5 * tq = 200 ns tq = (Baud rate Prescaler)/CAN Baud rate Prescaler = tq * CAN Baud rate Prescaler = 200E-9 * tq Clock Clock 25E6 = 5 tSync = 1 * tq = 200 ns \\fixed at 1 time quanta delay delay delay tProp \\400 is next integer multiple of tq of bus driver 50 ns of receiver circuit 30 ns of bus line (40m) 220 ns 400 ns = 2 * tq bit time = tSync + bit time = tSync + tPhase 1 + tPhase2 tPhase 1 + tPhase2 tPhase 1 + tPhase2 tPhase1 = 1 * tq tPhase2 = 1 * tq tTSeg1 + tTSeg2 = 5 * tq tProp + tPhase 1 + tPhase2 = bit time - tSync - tProp = (5 * tq) - (1 * tq) - (2 * tq) = 2 * tq \\tPhase2 = tPhase1 June 12, 2014 1027 Texas Instruments-Production Data Controller Area Network (CAN) Module tTSeg1 = tProp + tPhase1 tTSeg1 = (2 * tq) + (1 * tq) tTSeg1 = 3 * tq tTSeg2 = tPhase2 tTSeg2 = (Information Processing Time + 1) * tq tTSeg2 = 1 * tq \\Assumes IPT=0 tSJW = 1 * tq \\Least of 4, Phase1 and Phase2 In the above example, the bit field values for the CANBIT register are: = TSeg2 -1 TSEG2 = 1-1 =0 = TSeg1 -1 TSEG1 = 3-1 =2 = SJW -1 SJW = 1-1 =0 = Baud rate prescaler - 1 BRP = 5-1 =4 The final value programmed into the CANBIT register = 0x0204. 17.3.16.2 Example for Bit Timing at Low Baud Rate In this example, the frequency of the CAN clock is 50 MHz, and the bit rate is 100 Kbps. bit time = 10 µs = n * tq = 10 * tq tq = 1 µs tq = (Baud rate Prescaler)/CAN Clock Baud rate Prescaler = tq * CAN Clock Baud rate Prescaler = 1E-6 * 50E6 = 50 tSync = 1 * tq = 1 µs \\fixed at 1 time quanta delay delay delay tProp \\1 µs is next integer multiple of tq of bus driver 200 ns of receiver circuit 80 ns of bus line (40m) 220 ns 1 µs = 1 * tq bit time = tSync + bit time = tSync + tPhase 1 + tPhase2 tPhase 1 + tPhase2 tPhase 1 + tPhase2 tPhase1 = 4 * tq tPhase2 = 4 * tq tTSeg1 + tTSeg2 = 10 * tq tProp + tPhase 1 + tPhase2 = bit time - tSync - tProp = (10 * tq) - (1 * tq) - (1 * tq) = 8 * tq \\tPhase1 = tPhase2 1028 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller tTSeg1 tTSeg1 tTSeg1 tTSeg2 tTSeg2 tTSeg2 = = = = = = tProp + tPhase1 (1 * tq) + (4 * tq) 5 * tq tPhase2 (Information Processing Time + 4) × tq 4 * tq \\Assumes IPT=0 tSJW = 4 * tq \\Least of 4, Phase1, and Phase2 = TSeg2 -1 TSEG2 = 4-1 =3 = TSeg1 -1 TSEG1 = 5-1 =4 = SJW -1 SJW = 4-1 =3 = Baud rate prescaler - 1 BRP = 50-1 =49 The final value programmed into the CANBIT register = 0x34F1. 17.4 Register Map Table 17-5 on page 1029 lists the registers. All addresses given are relative to the CAN base address of: ■ CAN0: 0x4004.0000 Note that the CAN controller clock must be enabled before the registers can be programmed (see page 331). There must be a delay of 3 system clocks after the CAN module clock is enabled before any CAN module registers are accessed. Table 17-5. CAN Register Map Type Reset Description See page CANCTL RW 0x0000.0001 CAN Control 1031 0x004 CANSTS RW 0x0000.0000 CAN Status 1033 0x008 CANERR RO 0x0000.0000 CAN Error Counter 1036 0x00C CANBIT RW 0x0000.2301 CAN Bit Timing 1037 0x010 CANINT RO 0x0000.0000 CAN Interrupt 1038 0x014 CANTST RW 0x0000.0000 CAN Test 1039 0x018 CANBRPE RW 0x0000.0000 CAN Baud Rate Prescaler Extension 1041 0x020 CANIF1CRQ RW 0x0000.0001 CAN IF1 Command Request 1042 0x024 CANIF1CMSK RW 0x0000.0000 CAN IF1 Command Mask 1043 Offset Name 0x000 June 12, 2014 1029 Texas Instruments-Production Data Controller Area Network (CAN) Module Table 17-5. CAN Register Map (continued) Description See page 0x0000.FFFF CAN IF1 Mask 1 1046 RW 0x0000.FFFF CAN IF1 Mask 2 1047 CANIF1ARB1 RW 0x0000.0000 CAN IF1 Arbitration 1 1049 0x034 CANIF1ARB2 RW 0x0000.0000 CAN IF1 Arbitration 2 1050 0x038 CANIF1MCTL RW 0x0000.0000 CAN IF1 Message Control 1052 0x03C CANIF1DA1 RW 0x0000.0000 CAN IF1 Data A1 1055 0x040 CANIF1DA2 RW 0x0000.0000 CAN IF1 Data A2 1055 0x044 CANIF1DB1 RW 0x0000.0000 CAN IF1 Data B1 1055 0x048 CANIF1DB2 RW 0x0000.0000 CAN IF1 Data B2 1055 0x080 CANIF2CRQ RW 0x0000.0001 CAN IF2 Command Request 1042 0x084 CANIF2CMSK RW 0x0000.0000 CAN IF2 Command Mask 1043 0x088 CANIF2MSK1 RW 0x0000.FFFF CAN IF2 Mask 1 1046 0x08C CANIF2MSK2 RW 0x0000.FFFF CAN IF2 Mask 2 1047 0x090 CANIF2ARB1 RW 0x0000.0000 CAN IF2 Arbitration 1 1049 0x094 CANIF2ARB2 RW 0x0000.0000 CAN IF2 Arbitration 2 1050 0x098 CANIF2MCTL RW 0x0000.0000 CAN IF2 Message Control 1052 0x09C CANIF2DA1 RW 0x0000.0000 CAN IF2 Data A1 1055 0x0A0 CANIF2DA2 RW 0x0000.0000 CAN IF2 Data A2 1055 0x0A4 CANIF2DB1 RW 0x0000.0000 CAN IF2 Data B1 1055 0x0A8 CANIF2DB2 RW 0x0000.0000 CAN IF2 Data B2 1055 0x100 CANTXRQ1 RO 0x0000.0000 CAN Transmission Request 1 1056 0x104 CANTXRQ2 RO 0x0000.0000 CAN Transmission Request 2 1056 0x120 CANNWDA1 RO 0x0000.0000 CAN New Data 1 1057 0x124 CANNWDA2 RO 0x0000.0000 CAN New Data 2 1057 0x140 CANMSG1INT RO 0x0000.0000 CAN Message 1 Interrupt Pending 1058 0x144 CANMSG2INT RO 0x0000.0000 CAN Message 2 Interrupt Pending 1058 0x160 CANMSG1VAL RO 0x0000.0000 CAN Message 1 Valid 1059 0x164 CANMSG2VAL RO 0x0000.0000 CAN Message 2 Valid 1059 Offset Name Type Reset 0x028 CANIF1MSK1 RW 0x02C CANIF1MSK2 0x030 17.5 CAN Register Descriptions The remainder of this section lists and describes the CAN registers, in numerical order by address offset. There are two sets of Interface Registers that are used to access the Message Objects in the Message RAM: CANIF1x and CANIF2x. The function of the two sets are identical and are used to queue transactions. 1030 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 1: CAN Control (CANCTL), offset 0x000 This control register initializes the module and enables test mode and interrupts. The bus-off recovery sequence (see CAN Specification Rev. 2.0) cannot be shortened by setting or clearing INIT. If the device goes bus-off, it sets INIT, stopping all bus activities. Once INIT has been cleared by the CPU, the device then waits for 129 occurrences of Bus Idle (129 * 11 consecutive High bits) before resuming normal operations. At the end of the bus-off recovery sequence, the Error Management Counters are reset. During the waiting time after INIT is cleared, each time a sequence of 11 High bits has been monitored, a BITERROR0 code is written to the CANSTS register (the LEC field = 0x5), enabling the CPU to readily check whether the CAN bus is stuck Low or continuously disturbed, and to monitor the proceeding of the bus-off recovery sequence. CAN Control (CANCTL) CAN0 base: 0x4004.0000 Offset 0x000 Type RW, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 TEST CCE DAR reserved EIE SIE IE INIT RW 0 RW 0 RW 0 RO 0 RW 0 RW 0 RW 0 RW 1 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 TEST RW 0 6 5 CCE DAR RW RW 0 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Test Mode Enable Value Description 0 The CAN controller is operating normally. 1 The CAN controller is in test mode. Configuration Change Enable Value Description 0 Write accesses to the CANBIT register are not allowed. 1 Write accesses to the CANBIT register are allowed if the INIT bit is 1. Disable Automatic-Retransmission Value Description 0 Auto-retransmission of disturbed messages is enabled. 1 Auto-retransmission is disabled. June 12, 2014 1031 Texas Instruments-Production Data Controller Area Network (CAN) Module Bit/Field Name Type Reset 4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 EIE RW 0 Error Interrupt Enable 2 1 0 SIE IE INIT RW RW RW 0 0 1 Description Value Description 0 No error status interrupt is generated. 1 A change in the BOFF or EWARN bits in the CANSTS register generates an interrupt. Status Interrupt Enable Value Description 0 No status interrupt is generated. 1 An interrupt is generated when a message has successfully been transmitted or received, or a CAN bus error has been detected. A change in the TXOK, RXOK or LEC bits in the CANSTS register generates an interrupt. CAN Interrupt Enable Value Description 0 Interrupts disabled. 1 Interrupts enabled. Initialization Value Description 0 Normal operation. 1 Initialization started. 1032 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 2: CAN Status (CANSTS), offset 0x004 Important: This register is read-sensitive. See the register description for details. The status register contains information for interrupt servicing such as Bus-Off, error count threshold, and error types. The LEC field holds the code that indicates the type of the last error to occur on the CAN bus. This field is cleared when a message has been transferred (reception or transmission) without error. The unused error code 0x7 may be written by the CPU to manually set this field to an invalid error so that it can be checked for a change later. An error interrupt is generated by the BOFF and EWARN bits, and a status interrupt is generated by the RXOK, TXOK, and LEC bits, if the corresponding enable bits in the CAN Control (CANCTL) register are set. A change of the EPASS bit or a write to the RXOK, TXOK, or LEC bits does not generate an interrupt. Reading the CAN Status (CANSTS) register clears the CAN Interrupt (CANINT) register, if it is pending. CAN Status (CANSTS) CAN0 base: 0x4004.0000 Offset 0x004 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 BOFF EWARN EPASS RXOK TXOK RO 0 RO 0 RO 0 RW 0 RW 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 BOFF RO 0 6 EWARN RO 0 LEC RW 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Bus-Off Status Value Description 0 The CAN controller is not in bus-off state. 1 The CAN controller is in bus-off state. Warning Status Value Description 0 Both error counters are below the error warning limit of 96. 1 At least one of the error counters has reached the error warning limit of 96. June 12, 2014 1033 Texas Instruments-Production Data Controller Area Network (CAN) Module Bit/Field Name Type Reset 5 EPASS RO 0 4 RXOK RW 0 Description Error Passive Value Description 0 The CAN module is in the Error Active state, that is, the receive or transmit error count is less than or equal to 127. 1 The CAN module is in the Error Passive state, that is, the receive or transmit error count is greater than 127. Received a Message Successfully Value Description 0 Since this bit was last cleared, no message has been successfully received. 1 Since this bit was last cleared, a message has been successfully received, independent of the result of the acceptance filtering. This bit must be cleared by writing a 0 to it. 3 TXOK RW 0 Transmitted a Message Successfully Value Description 0 Since this bit was last cleared, no message has been successfully transmitted. 1 Since this bit was last cleared, a message has been successfully transmitted error-free and acknowledged by at least one other node. This bit must be cleared by writing a 0 to it. 1034 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 2:0 LEC RW 0x0 Description Last Error Code This is the type of the last error to occur on the CAN bus. Value Description 0x0 No Error 0x1 Stuff Error More than 5 equal bits in a sequence have occurred in a part of a received message where this is not allowed. 0x2 Format Error A fixed format part of the received frame has the wrong format. 0x3 ACK Error The message transmitted was not acknowledged by another node. 0x4 Bit 1 Error When a message is transmitted, the CAN controller monitors the data lines to detect any conflicts. When the arbitration field is transmitted, data conflicts are a part of the arbitration protocol. When other frame fields are transmitted, data conflicts are considered errors. A Bit 1 Error indicates that the device wanted to send a High level (logical 1) but the monitored bus value was Low (logical 0). 0x5 Bit 0 Error A Bit 0 Error indicates that the device wanted to send a Low level (logical 0), but the monitored bus value was High (logical 1). During bus-off recovery, this status is set each time a sequence of 11 High bits has been monitored. By checking for this status, software can monitor the proceeding of the bus-off recovery sequence without any disturbances to the bus. 0x6 CRC Error The CRC checksum was incorrect in the received message, indicating that the calculated value received did not match the calculated CRC of the data. 0x7 No Event When the LEC bit shows this value, no CAN bus event was detected since this value was written to the LEC field. June 12, 2014 1035 Texas Instruments-Production Data Controller Area Network (CAN) Module Register 3: CAN Error Counter (CANERR), offset 0x008 This register contains the error counter values, which can be used to analyze the cause of an error. CAN Error Counter (CANERR) CAN0 base: 0x4004.0000 Offset 0x008 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RP Type Reset RO 0 REC TEC RO 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 RP RO 0 14:8 REC RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Received Error Passive Value Description 0 The Receive Error counter is below the Error Passive level (127 or less). 1 The Receive Error counter has reached the Error Passive level (128 or greater). Receive Error Counter This field contains the state of the receiver error counter (0 to 127). 7:0 TEC RO 0x00 Transmit Error Counter This field contains the state of the transmit error counter (0 to 255). 1036 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 4: CAN Bit Timing (CANBIT), offset 0x00C This register is used to program the bit width and bit quantum. Values are programmed to the system clock frequency. This register is write-enabled by setting the CCE and INIT bits in the CANCTL register. See “Bit Time and Bit Rate” on page 1024 for more information. CAN Bit Timing (CANBIT) CAN0 base: 0x4004.0000 Offset 0x00C Type RW, reset 0x0000.2301 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RW 0 RW 0 RW 0 RW 1 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RW 1 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 1 reserved Type Reset reserved Type Reset RO 0 TSEG2 RW 0 RW 1 TSEG1 Bit/Field Name Type Reset 31:15 reserved RO 0x0000 14:12 TSEG2 RW 0x2 SJW BRP Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Time Segment after Sample Point 0x00-0x07: The actual interpretation by the hardware of this value is such that one more than the value programmed here is used. So, for example, the reset value of 0x2 means that 3 (2+1) bit time quanta are defined for Phase2 (see Figure 17-4 on page 1025). The bit time quanta is defined by the BRP field. 11:8 TSEG1 RW 0x3 Time Segment Before Sample Point 0x00-0x0F: The actual interpretation by the hardware of this value is such that one more than the value programmed here is used. So, for example, the reset value of 0x3 means that 4 (3+1) bit time quanta are defined for Phase1 (see Figure 17-4 on page 1025). The bit time quanta is defined by the BRP field. 7:6 SJW RW 0x0 (Re)Synchronization Jump Width 0x00-0x03: The actual interpretation by the hardware of this value is such that one more than the value programmed here is used. During the start of frame (SOF), if the CAN controller detects a phase error (misalignment), it can adjust the length of TSEG2 or TSEG1 by the value in SJW. So the reset value of 0 adjusts the length by 1 bit time quanta. 5:0 BRP RW 0x1 Baud Rate Prescaler The value by which the oscillator frequency is divided for generating the bit time quanta. The bit time is built up from a multiple of this quantum. 0x00-0x03F: The actual interpretation by the hardware of this value is such that one more than the value programmed here is used. BRP defines the number of CAN clock periods that make up 1 bit time quanta, so the reset value is 2 bit time quanta (1+1). The CANBRPE register can be used to further divide the bit time. June 12, 2014 1037 Texas Instruments-Production Data Controller Area Network (CAN) Module Register 5: CAN Interrupt (CANINT), offset 0x010 This register indicates the source of the interrupt. If several interrupts are pending, the CAN Interrupt (CANINT) register points to the pending interrupt with the highest priority, disregarding the order in which the interrupts occurred. An interrupt remains pending until the CPU has cleared it. If the INTID field is not 0x0000 (the default) and the IE bit in the CANCTL register is set, the interrupt is active. The interrupt line remains active until the INTID field is cleared by reading the CANSTS register, or until the IE bit in the CANCTL register is cleared. Note: Reading the CAN Status (CANSTS) register clears the CAN Interrupt (CANINT) register, if it is pending. CAN Interrupt (CANINT) CAN0 base: 0x4004.0000 Offset 0x010 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset INTID Type Reset Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 INTID RO 0x0000 Interrupt Identifier The number in this field indicates the source of the interrupt. Value Description 0x0000 No interrupt pending 0x0001-0x0020 Number of the message object that caused the interrupt 0x0021-0x7FFF Reserved 0x8000 Status Interrupt 0x8001-0xFFFF Reserved 1038 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 6: CAN Test (CANTST), offset 0x014 This register is used for self-test and external pin access. It is write-enabled by setting the TEST bit in the CANCTL register. Different test functions may be combined, however, CAN transfers are affected if the TX bits in this register are not zero. CAN Test (CANTST) CAN0 base: 0x4004.0000 Offset 0x014 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 LBACK SILENT BASIC RO 0 RO 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset RX RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 RX RO 0 6:5 TX RW 0x0 TX RW 0 RW 0 reserved RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Receive Observation Value Description 0 The CANnRx pin is low. 1 The CANnRx pin is high. Transmit Control Overrides control of the CANnTx pin. Value Description 0x0 CAN Module Control CANnTx is controlled by the CAN module; default operation 0x1 Sample Point The sample point is driven on the CANnTx signal. This mode is useful to monitor bit timing. 0x2 Driven Low CANnTx drives a low value. This mode is useful for checking the physical layer of the CAN bus. 0x3 Driven High CANnTx drives a high value. This mode is useful for checking the physical layer of the CAN bus. June 12, 2014 1039 Texas Instruments-Production Data Controller Area Network (CAN) Module Bit/Field Name Type Reset 4 LBACK RW 0 3 2 1:0 SILENT BASIC reserved RW RW RO 0 0 0x0 Description Loopback Mode Value Description 0 Loopback mode is disabled. 1 Loopback mode is enabled. In loopback mode, the data from the transmitter is routed into the receiver. Any data on the receive input is ignored. Silent Mode Value Description 0 Silent mode is disabled. 1 Silent mode is enabled. In silent mode, the CAN controller does not transmit data but instead monitors the bus. This mode is also known as Bus Monitor mode. Basic Mode Value Description 0 Basic mode is disabled. 1 Basic mode is enabled. In basic mode, software should use the CANIF1 registers as the transmit buffer and use the CANIF2 registers as the receive buffer. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1040 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 7: CAN Baud Rate Prescaler Extension (CANBRPE), offset 0x018 This register is used to further divide the bit time set with the BRP bit in the CANBIT register. It is write-enabled by setting the CCE bit in the CANCTL register. CAN Baud Rate Prescaler Extension (CANBRPE) CAN0 base: 0x4004.0000 Offset 0x018 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:4 reserved RO 0x0000.000 3:0 BRPE RW 0x0 BRPE Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Baud Rate Prescaler Extension 0x00-0x0F: Extend the BRP bit in the CANBIT register to values up to 1023. The actual interpretation by the hardware is one more than the value programmed by BRPE (MSBs) and BRP (LSBs). June 12, 2014 1041 Texas Instruments-Production Data Controller Area Network (CAN) Module Register 8: CAN IF1 Command Request (CANIF1CRQ), offset 0x020 Register 9: CAN IF2 Command Request (CANIF2CRQ), offset 0x080 A message transfer is started as soon as there is a write of the message object number to the MNUM field when the TXRQST bit in the CANIF1MCTL register is set. With this write operation, the BUSY bit is automatically set to indicate that a transfer between the CAN Interface Registers and the internal message RAM is in progress. After a wait time of 3 to 6 CAN_CLK periods, the transfer between the interface register and the message RAM completes, which then clears the BUSY bit. CAN IFn Command Request (CANIFnCRQ) CAN0 base: 0x4004.0000 Offset 0x020 Type RW, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 1 reserved Type Reset BUSY Type Reset RO 0 reserved RO 0 MNUM Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 BUSY RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Busy Flag Value Description 0 This bit is cleared when read/write action has finished. 1 This bit is set when a write occurs to the message number in this register. 14:6 reserved RO 0x00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5:0 MNUM RW 0x01 Message Number Selects one of the 32 message objects in the message RAM for data transfer. The message objects are numbered from 1 to 32. Value Description 0x00 Reserved 0 is not a valid message number; it is interpreted as 0x20, or object 32. 0x01-0x20 Message Number Indicates specified message object 1 to 32. 0x21-0x3F Reserved Not a valid message number; values are shifted and it is interpreted as 0x01-0x1F. 1042 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 10: CAN IF1 Command Mask (CANIF1CMSK), offset 0x024 Register 11: CAN IF2 Command Mask (CANIF2CMSK), offset 0x084 Reading the Command Mask registers provides status for various functions. Writing to the Command Mask registers specifies the transfer direction and selects which buffer registers are the source or target of the data transfer. Note that when a read from the message object buffer occurs when the WRNRD bit is clear and the CLRINTPND and/or NEWDAT bits are set, the interrupt pending and/or new data flags in the message object buffer are cleared. CAN IFn Command Mask (CANIFnCMSK) CAN0 base: 0x4004.0000 Offset 0x024 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WRNRD MASK ARB CONTROL CLRINTPND NEWDAT / TXRQST reserved DATAA DATAB RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000.00 7 WRNRD RW 0 6 MASK RW 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Write, Not Read Value Description 0 Transfer the data in the CAN message object specified by the MNUM field in the CANIFnCRQ register into the CANIFn registers. 1 Transfer the data in the CANIFn registers to the CAN message object specified by the MNUM field in the CAN Command Request (CANIFnCRQ). Note: Interrupt pending and new data conditions in the message buffer can be cleared by reading from the buffer (WRNRD = 0) when the CLRINTPND and/or NEWDAT bits are set. Access Mask Bits Value Description 0 Mask bits unchanged. 1 Transfer IDMASK + DIR + MXTD of the message object into the Interface registers. June 12, 2014 1043 Texas Instruments-Production Data Controller Area Network (CAN) Module Bit/Field Name Type Reset 5 ARB RW 0 4 3 CONTROL CLRINTPND RW RW 0 0 Description Access Arbitration Bits Value Description 0 Arbitration bits unchanged. 1 Transfer ID + DIR + XTD + MSGVAL of the message object into the Interface registers. Access Control Bits Value Description 0 Control bits unchanged. 1 Transfer control bits from the CANIFnMCTL register into the Interface registers. Clear Interrupt Pending Bit The function of this bit depends on the configuration of the WRNRD bit. Value Description 0 If WRNRD is clear, the interrupt pending status is transferred from the message buffer into the CANIFnMCTL register. If WRNRD is set, the INTPND bit in the message object remains unchanged. 1 If WRNRD is clear, the interrupt pending status is cleared in the message buffer. Note the value of this bit that is transferred to the CANIFnMCTL register always reflects the status of the bits before clearing. If WRNRD is set, the INTPND bit is cleared in the message object. 2 NEWDAT / TXRQST RW 0 NEWDAT / TXRQST Bit The function of this bit depends on the configuration of the WRNRD bit. Value Description 0 If WRNRD is clear, the value of the new data status is transferred from the message buffer into the CANIFnMCTL register. If WRNRD is set, a transmission is not requested. 1 If WRNRD is clear, the new data status is cleared in the message buffer. Note the value of this bit that is transferred to the CANIFnMCTL register always reflects the status of the bits before clearing. If WRNRD is set, a transmission is requested. Note that when this bit is set, the TXRQST bit in the CANIFnMCTL register is ignored. 1044 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 1 DATAA RW 0 Description Access Data Byte 0 to 3 The function of this bit depends on the configuration of the WRNRD bit. Value Description 0 Data bytes 0-3 are unchanged. 1 If WRNRD is clear, transfer data bytes 0-3 in CANIFnDA1 and CANIFnDA2 to the message object. If WRNRD is set, transfer data bytes 0-3 in message object to CANIFnDA1 and CANIFnDA2. 0 DATAB RW 0 Access Data Byte 4 to 7 The function of this bit depends on the configuration of the WRNRD bit as follows: Value Description 0 Data bytes 4-7 are unchanged. 1 If WRNRD is clear, transfer data bytes 4-7 in CANIFnDA1 and CANIFnDA2 to the message object. If WRNRD is set, transfer data bytes 4-7 in message object to CANIFnDA1 and CANIFnDA2. June 12, 2014 1045 Texas Instruments-Production Data Controller Area Network (CAN) Module Register 12: CAN IF1 Mask 1 (CANIF1MSK1), offset 0x028 Register 13: CAN IF2 Mask 1 (CANIF2MSK1), offset 0x088 The mask information provided in this register accompanies the data (CANIFnDAn), arbitration information (CANIFnARBn), and control information (CANIFnMCTL) to the message object in the message RAM. The mask is used with the ID bit in the CANIFnARBn register for acceptance filtering. Additional mask information is contained in the CANIFnMSK2 register. CAN IFn Mask 1 (CANIFnMSK1) CAN0 base: 0x4004.0000 Offset 0x028 Type RW, reset 0x0000.FFFF 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 reserved Type Reset MSK Type Reset Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 MSK RW 0xFFFF Identifier Mask When using a 29-bit identifier, these bits are used for bits [15:0] of the ID. The MSK field in the CANIFnMSK2 register are used for bits [28:16] of the ID. When using an 11-bit identifier, these bits are ignored. Value Description 0 The corresponding identifier field (ID) in the message object cannot inhibit the match in acceptance filtering. 1 The corresponding identifier field (ID) is used for acceptance filtering. 1046 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 14: CAN IF1 Mask 2 (CANIF1MSK2), offset 0x02C Register 15: CAN IF2 Mask 2 (CANIF2MSK2), offset 0x08C This register holds extended mask information that accompanies the CANIFnMSK1 register. CAN IFn Mask 2 (CANIFnMSK2) CAN0 base: 0x4004.0000 Offset 0x02C Type RW, reset 0x0000.FFFF 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 MXTD MDIR reserved RW 1 RW 1 RO 1 RW 0 RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RW 0 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 RW 1 reserved Type Reset Type Reset MSK Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 MXTD RW 1 14 13 MDIR reserved RW RO 1 1 RW 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Mask Extended Identifier Value Description 0 The extended identifier bit (XTD in the CANIFnARB2 register) has no effect on the acceptance filtering. 1 The extended identifier bit XTD is used for acceptance filtering. Mask Message Direction Value Description 0 The message direction bit (DIR in the CANIFnARB2 register) has no effect for acceptance filtering. 1 The message direction bit DIR is used for acceptance filtering. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 12, 2014 1047 Texas Instruments-Production Data Controller Area Network (CAN) Module Bit/Field Name Type Reset Description 12:0 MSK RW 0xFF Identifier Mask When using a 29-bit identifier, these bits are used for bits [28:16] of the ID. The MSK field in the CANIFnMSK1 register are used for bits [15:0] of the ID. When using an 11-bit identifier, MSK[12:2] are used for bits [10:0] of the ID. Value Description 0 The corresponding identifier field (ID) in the message object cannot inhibit the match in acceptance filtering. 1 The corresponding identifier field (ID) is used for acceptance filtering. 1048 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 16: CAN IF1 Arbitration 1 (CANIF1ARB1), offset 0x030 Register 17: CAN IF2 Arbitration 1 (CANIF2ARB1), offset 0x090 These registers hold the identifiers for acceptance filtering. CAN IFn Arbitration 1 (CANIFnARB1) CAN0 base: 0x4004.0000 Offset 0x030 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset ID Type Reset Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 ID RW 0x0000 Message Identifier This bit field is used with the ID field in the CANIFnARB2 register to create the message identifier. When using a 29-bit identifier, bits 15:0 of the CANIFnARB1 register are [15:0] of the ID, while bits 12:0 of the CANIFnARB2 register are [28:16] of the ID. When using an 11-bit identifier, these bits are not used. June 12, 2014 1049 Texas Instruments-Production Data Controller Area Network (CAN) Module Register 18: CAN IF1 Arbitration 2 (CANIF1ARB2), offset 0x034 Register 19: CAN IF2 Arbitration 2 (CANIF2ARB2), offset 0x094 These registers hold information for acceptance filtering. CAN IFn Arbitration 2 (CANIFnARB2) CAN0 base: 0x4004.0000 Offset 0x034 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 MSGVAL XTD DIR RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset Type Reset ID Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 MSGVAL RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Message Valid Value Description 0 The message object is ignored by the message handler. 1 The message object is configured and ready to be considered by the message handler within the CAN controller. All unused message objects should have this bit cleared during initialization and before clearing the INIT bit in the CANCTL register. The MSGVAL bit must also be cleared before any of the following bits are modified or if the message object is no longer required: the ID fields in the CANIFnARBn registers, the XTD and DIR bits in the CANIFnARB2 register, or the DLC field in the CANIFnMCTL register. 14 XTD RW 0 Extended Identifier Value Description 0 An 11-bit Standard Identifier is used for this message object. 1 A 29-bit Extended Identifier is used for this message object. 1050 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 13 DIR RW 0 12:0 ID RW 0x000 Description Message Direction Value Description 0 Receive. When the TXRQST bit in the CANIFnMCTL register is set, a remote frame with the identifier of this message object is received. On reception of a data frame with matching identifier, that message is stored in this message object. 1 Transmit. When the TXRQST bit in the CANIFnMCTL register is set, the respective message object is transmitted as a data frame. On reception of a remote frame with matching identifier, the TXRQST bit of this message object is set (if RMTEN=1). Message Identifier This bit field is used with the ID field in the CANIFnARB2 register to create the message identifier. When using a 29-bit identifier, ID[15:0] of the CANIFnARB1 register are [15:0] of the ID, while these bits, ID[12:0], are [28:16] of the ID. When using an 11-bit identifier, ID[12:2] are used for bits [10:0] of the ID. The ID field in the CANIFnARB1 register is ignored. June 12, 2014 1051 Texas Instruments-Production Data Controller Area Network (CAN) Module Register 20: CAN IF1 Message Control (CANIF1MCTL), offset 0x038 Register 21: CAN IF2 Message Control (CANIF2MCTL), offset 0x098 This register holds the control information associated with the message object to be sent to the Message RAM. CAN IFn Message Control (CANIFnMCTL) CAN0 base: 0x4004.0000 Offset 0x038 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 UMASK TXIE RXIE RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RMTEN TXRQST EOB RW 0 RW 0 RW 0 RO 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset NEWDAT MSGLST INTPND Type Reset RW 0 RW 0 RW 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 NEWDAT RW 0 14 MSGLST RW 0 reserved RO 0 RO 0 DLC Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. New Data Value Description 0 No new data has been written into the data portion of this message object by the message handler since the last time this flag was cleared by the CPU. 1 The message handler or the CPU has written new data into the data portion of this message object. Message Lost Value Description 0 No message was lost since the last time this bit was cleared by the CPU. 1 The message handler stored a new message into this object when NEWDAT was set; the CPU has lost a message. This bit is only valid for message objects when the DIR bit in the CANIFnARB2 register is clear (receive). 13 INTPND RW 0 Interrupt Pending Value Description 0 This message object is not the source of an interrupt. 1 This message object is the source of an interrupt. The interrupt identifier in the CANINT register points to this message object if there is not another interrupt source with a higher priority. 1052 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 12 UMASK RW 0 11 10 9 8 TXIE RXIE RMTEN TXRQST RW RW RW RW 0 0 0 0 Description Use Acceptance Mask Value Description 0 Mask is ignored. 1 Use mask (MSK, MXTD, and MDIR bits in the CANIFnMSKn registers) for acceptance filtering. Transmit Interrupt Enable Value Description 0 The INTPND bit in the CANIFnMCTL register is unchanged after a successful transmission of a frame. 1 The INTPND bit in the CANIFnMCTL register is set after a successful transmission of a frame. Receive Interrupt Enable Value Description 0 The INTPND bit in the CANIFnMCTL register is unchanged after a successful reception of a frame. 1 The INTPND bit in the CANIFnMCTL register is set after a successful reception of a frame. Remote Enable Value Description 0 At the reception of a remote frame, the TXRQST bit in the CANIFnMCTL register is left unchanged. 1 At the reception of a remote frame, the TXRQST bit in the CANIFnMCTL register is set. Transmit Request Value Description 0 This message object is not waiting for transmission. 1 The transmission of this message object is requested and is not yet done. Note: If the WRNRD and TXRQST bits in the CANIFnCMSK register are set, this bit is ignored. June 12, 2014 1053 Texas Instruments-Production Data Controller Area Network (CAN) Module Bit/Field Name Type Reset 7 EOB RW 0 Description End of Buffer Value Description 0 Message object belongs to a FIFO Buffer and is not the last message object of that FIFO Buffer. 1 Single message object or last message object of a FIFO Buffer. This bit is used to concatenate two or more message objects (up to 32) to build a FIFO buffer. For a single message object (thus not belonging to a FIFO buffer), this bit must be set. 6:4 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3:0 DLC RW 0x0 Data Length Code Value Description 0x0-0x8 Specifies the number of bytes in the data frame. 0x9-0xF Defaults to a data frame with 8 bytes. The DLC field in the CANIFnMCTL register of a message object must be defined the same as in all the corresponding objects with the same identifier at other nodes. When the message handler stores a data frame, it writes DLC to the value given by the received message. 1054 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 22: CAN IF1 Data A1 (CANIF1DA1), offset 0x03C Register 23: CAN IF1 Data A2 (CANIF1DA2), offset 0x040 Register 24: CAN IF1 Data B1 (CANIF1DB1), offset 0x044 Register 25: CAN IF1 Data B2 (CANIF1DB2), offset 0x048 Register 26: CAN IF2 Data A1 (CANIF2DA1), offset 0x09C Register 27: CAN IF2 Data A2 (CANIF2DA2), offset 0x0A0 Register 28: CAN IF2 Data B1 (CANIF2DB1), offset 0x0A4 Register 29: CAN IF2 Data B2 (CANIF2DB2), offset 0x0A8 These registers contain the data to be sent or that has been received. In a CAN data frame, data byte 0 is the first byte to be transmitted or received and data byte 7 is the last byte to be transmitted or received. In CAN's serial bit stream, the MSB of each byte is transmitted first. CAN IFn Data nn (CANIFnDnn) CAN0 base: 0x4004.0000 Offset 0x03C Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 reserved Type Reset DATA Type Reset Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 DATA RW 0x0000 Data The CANIFnDA1 registers contain data bytes 1 and 0; CANIFnDA2 data bytes 3 and 2; CANIFnDB1 data bytes 5 and 4; and CANIFnDB2 data bytes 7 and 6. June 12, 2014 1055 Texas Instruments-Production Data Controller Area Network (CAN) Module Register 30: CAN Transmission Request 1 (CANTXRQ1), offset 0x100 Register 31: CAN Transmission Request 2 (CANTXRQ2), offset 0x104 The CANTXRQ1 and CANTXRQ2 registers hold the TXRQST bits of the 32 message objects. By reading out these bits, the CPU can check which message object has a transmission request pending. The TXRQST bit of a specific message object can be changed by three sources: (1) the CPU via the CANIFnMCTL register, (2) the message handler state machine after the reception of a remote frame, or (3) the message handler state machine after a successful transmission. The CANTXRQ1 register contains the TXRQST bits of the first 16 message objects in the message RAM; the CANTXRQ2 register contains the TXRQST bits of the second 16 message objects. CAN Transmission Request n (CANTXRQn) CAN0 base: 0x4004.0000 Offset 0x100 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 TXRQST Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 TXRQST RO 0x0000 Transmission Request Bits Value Description 0 The corresponding message object is not waiting for transmission. 1 The transmission of the corresponding message object is requested and is not yet done. 1056 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 32: CAN New Data 1 (CANNWDA1), offset 0x120 Register 33: CAN New Data 2 (CANNWDA2), offset 0x124 The CANNWDA1 and CANNWDA2 registers hold the NEWDAT bits of the 32 message objects. By reading these bits, the CPU can check which message object has its data portion updated. The NEWDAT bit of a specific message object can be changed by three sources: (1) the CPU via the CANIFnMCTL register, (2) the message handler state machine after the reception of a data frame, or (3) the message handler state machine after a successful transmission. The CANNWDA1 register contains the NEWDAT bits of the first 16 message objects in the message RAM; the CANNWDA2 register contains the NEWDAT bits of the second 16 message objects. CAN New Data n (CANNWDAn) CAN0 base: 0x4004.0000 Offset 0x120 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 NEWDAT Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 NEWDAT RO 0x0000 New Data Bits Value Description 0 No new data has been written into the data portion of the corresponding message object by the message handler since the last time this flag was cleared by the CPU. 1 The message handler or the CPU has written new data into the data portion of the corresponding message object. June 12, 2014 1057 Texas Instruments-Production Data Controller Area Network (CAN) Module Register 34: CAN Message 1 Interrupt Pending (CANMSG1INT), offset 0x140 Register 35: CAN Message 2 Interrupt Pending (CANMSG2INT), offset 0x144 The CANMSG1INT and CANMSG2INT registers hold the INTPND bits of the 32 message objects. By reading these bits, the CPU can check which message object has an interrupt pending. The INTPND bit of a specific message object can be changed through two sources: (1) the CPU via the CANIFnMCTL register, or (2) the message handler state machine after the reception or transmission of a frame. This field is also encoded in the CANINT register. The CANMSG1INT register contains the INTPND bits of the first 16 message objects in the message RAM; the CANMSG2INT register contains the INTPND bits of the second 16 message objects. CAN Message n Interrupt Pending (CANMSGnINT) CAN0 base: 0x4004.0000 Offset 0x140 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset INTPND Type Reset Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 INTPND RO 0x0000 Interrupt Pending Bits Value Description 0 The corresponding message object is not the source of an interrupt. 1 The corresponding message object is the source of an interrupt. 1058 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 36: CAN Message 1 Valid (CANMSG1VAL), offset 0x160 Register 37: CAN Message 2 Valid (CANMSG2VAL), offset 0x164 The CANMSG1VAL and CANMSG2VAL registers hold the MSGVAL bits of the 32 message objects. By reading these bits, the CPU can check which message object is valid. The message valid bit of a specific message object can be changed with the CANIFnARB2 register. The CANMSG1VAL register contains the MSGVAL bits of the first 16 message objects in the message RAM; the CANMSG2VAL register contains the MSGVAL bits of the second 16 message objects in the message RAM. CAN Message n Valid (CANMSGnVAL) CAN0 base: 0x4004.0000 Offset 0x160 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 MSGVAL Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 MSGVAL RO 0x0000 Message Valid Bits Value Description 0 The corresponding message object is not configured and is ignored by the message handler. 1 The corresponding message object is configured and should be considered by the message handler. June 12, 2014 1059 Texas Instruments-Production Data Analog Comparators 18 Analog Comparators An analog comparator is a peripheral that compares two analog voltages and provides a logical output that signals the comparison result. Note: Not all comparators have the option to drive an output pin. See “Signal Description” on page 1061 for more information. The comparator can provide its output to a device pin, acting as a replacement for an analog comparator on the board. In addition, the comparator can signal the application via interrupts or trigger the start of a sample sequence in the ADC. The interrupt generation and ADC triggering logic is separate and independent. This flexibility means, for example, that an interrupt can be generated on a rising edge and the ADC triggered on a falling edge. The TM4C1231H6PM microcontroller provides two independent integrated analog comparators with the following functions: ■ Compare external pin input to external pin input or to internal programmable voltage reference ■ Compare a test voltage against any one of the following voltages: – An individual external reference voltage – A shared single external reference voltage – A shared internal reference voltage 1060 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 18.1 Block Diagram Figure 18-1. Analog Comparator Module Block Diagram C2- -ve input C2+ +ve input Comparator 2 output +ve input (alternate) ACCTL2 trigger ACSTAT2 C2o trigger interrupt reference input C1- -ve input C1+ +ve input Comparator 1 output C1o +ve input (alternate) ACCTL1 trigger trigger ACSTAT1 interrupt reference input C0- -ve input C0+ +ve input Comparator 0 output C0o +ve input (alternate) ACCTL0 ACSTAT0 trigger trigger interrupt reference input Voltage Ref Interrupt Control ACRIS Internal Bus Interrupt ACREFCTL ACMIS ACINTEN Module Status ACMPPP Note: 18.2 This block diagram depicts the maximum number of analog comparators and comparator outputs for the family of microcontrollers; the number for this specific device may vary. See page 1074 for what is included on this device. Signal Description The following table lists the external signals of the Analog Comparators and describes the function of each. The Analog Comparator output signals are alternate functions for some GPIO signals and default to be GPIO signals at reset. The column in the table below titled "Pin Mux/Pin Assignment" lists the possible GPIO pin placements for the Analog Comparator signals. The AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register (page 636) should be set to choose the Analog Comparator function. The number in parentheses is the encoding that must be programmed into the PMCn field in the GPIO Port Control (GPIOPCTL) register (page 653) to assign the Analog Comparator signal to the specified GPIO port pin. The positive and negative input signals are configured by clearing the DEN bit in the GPIO Digital Enable (GPIODEN) register. For more information on configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 614. Table 18-1. Analog Comparators Signals (64LQFP) Pin Name C0+ Pin Number Pin Mux / Pin Assignment 14 PC6 a Pin Type Buffer Type I Analog Description Analog comparator 0 positive input. June 12, 2014 1061 Texas Instruments-Production Data Analog Comparators Table 18-1. Analog Comparators Signals (64LQFP) (continued) Pin Name Pin Number Pin Mux / Pin Assignment a Pin Type Buffer Type Analog Description C0- 13 PC7 I Analog comparator 0 negative input. C0o 28 PF0 (9) O TTL C1+ 15 PC5 I Analog Analog comparator 1 positive input. C1- 16 PC4 I Analog Analog comparator 1 negative input. C1o 29 PF1 (9) O TTL Analog comparator 0 output. Analog comparator 1 output. a. The TTL designation indicates the pin has TTL-compatible voltage levels. 18.3 Functional Description The comparator compares the VIN- and VIN+ inputs to produce an output, VOUT. VIN- < VIN+, VOUT = 1 VIN- > VIN+, VOUT = 0 As shown in Figure 18-2 on page 1062, the input source for VIN- is an external input, Cn-, where n is the analog comparator number. In addition to an external input, Cn+, input sources for VIN+ can be the C0+ or an internal reference, VIREF. Figure 18-2. Structure of Comparator Unit -ve input reference input output CINV 1 IntGen 2 TrigGen ACCTL ACSTAT trigger interrupt +ve input (alternate) 0 internal bus +ve input A comparator is configured through two status/control registers, Analog Comparator Control (ACCTL) and Analog Comparator Status (ACSTAT). The internal reference is configured through one control register, Analog Comparator Reference Voltage Control (ACREFCTL). Interrupt status and control are configured through three registers, Analog Comparator Masked Interrupt Status (ACMIS), Analog Comparator Raw Interrupt Status (ACRIS), and Analog Comparator Interrupt Enable (ACINTEN). Typically, the comparator output is used internally to generate an interrupt as controlled by the ISEN bit in the ACCTL register. The output may also be used to drive one of the external pins (Cno), or generate an analog-to-digital converter (ADC) trigger. Important: The ASRCP bits in the ACCTL register must be set before using the analog comparators. 1062 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 18.3.1 Internal Reference Programming The structure of the internal reference is shown in Figure 18-3 on page 1063. The internal reference is controlled by a single configuration register (ACREFCTL). Figure 18-3. Comparator Internal Reference Structure N*R N*R 0xF 0xE 0x1 0x0 Decoder Note: internal reference VIREF In the figure above, N*R represents a multiple of the R value that produces the results specified in Table 18-2 on page 1063. The internal reference can be programmed in one of two modes (low range or high range) depending on the RNG bit in the ACREFCTL register. When RNG is clear, the internal reference is in high-range mode, and when RNG is set the internal reference is in low-range mode. In each range, the internal reference, VIREF, has 16 preprogrammed thresholds or step values. The threshold to be used to compare the external input voltage against is selected using the VREF field in the ACREFCTL register. In the high-range mode, the VIREF threshold voltages start at the ideal high-range starting voltage of VDDA/4.2 and increase in ideal constant voltage steps of VDDA/29.4. In the low-range mode, the VIREF threshold voltages start at 0 V and increase in ideal constant voltage steps of VDDA/22.12. The ideal VIREF step voltages for each mode and their dependence on the RNG and VREF fields are summarized in Table 18-2. Table 18-2. Internal Reference Voltage and ACREFCTL Field Values ACREFCTL Register EN Bit Value EN=0 RNG Bit Value Output Reference Voltage Based on VREF Field Value RNG=X 0 V (GND) for any value of VREF. It is recommended that RNG=1 and VREF=0 to minimize noise on the reference ground. RNG=0 VIREF High Range: 16 voltage threshold values indexed by VREF = 0x0 .. 0xF Ideal starting voltage (VREF=0): VDDA / 4.2 Ideal step size: VDDA/ 29.4 Ideal VIREF threshold values: VIREF (VREF) = VDDA / 4.2 + VREF * (VDDA/ 29.4), for VREF = 0x0 .. 0xF For minimum and maximum VIREF threshold values, see Table 18-3 on page 1064. EN=1 RNG=1 VIREF Low Range: 16 voltage threshold values indexed by VREF = 0x0 .. 0xF Ideal starting voltage (VREF=0): 0 V Ideal step size: VDDA/ 22.12 Ideal VIREF threshold values: VIREF (VREF) = VREF * (VDDA/ 22.12), for VREF = 0x0 .. 0xF For minimum and maximum VIREF threshold values, see Table 18-4 on page 1064. June 12, 2014 1063 Texas Instruments-Production Data Analog Comparators Note that the values shown in Table 18-2 are the ideal values of the VIREF thresholds. These values actually vary between minimum and maximum values for each threshold step, depending on process and temperature. The minimum and maximum values for each step are given by: ■ VIREF(VREF) [Min] = Ideal VIREF(VREF) – (Ideal Step size – 2 mV) / 2 ■ VIREF(VREF) [Max] = Ideal VIREF(VREF) + (Ideal Step size – 2 mV) / 2 Examples of minimum and maximum VIREF values for VDDA = 3.3V for high and low ranges, are shown inTable 18-3 and Table 18-4. Note that these examples are only valid for VDDA = 3.3V; values scale up and down with VDDA. Table 18-3. Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 0 VREF Value VIREF Min Ideal VIREF VIREF Max Unit 0x0 0.731 0.786 0.841 V 0x1 0.843 0.898 0.953 V 0x2 0.955 1.010 1.065 V 0x3 1.067 1.122 1.178 V 0x4 1.180 1.235 1.290 V 0x5 1.292 1.347 1.402 V 0x6 1.404 1.459 1.514 V 0x7 1.516 1.571 1.627 V 0x8 1.629 1.684 1.739 V 0x9 1.741 1.796 1.851 V 0xA 1.853 1.908 1.963 V 0xB 1.965 2.020 2.076 V 0xC 2.078 2.133 2.188 V 0xD 2.190 2.245 2.300 V 0xE 2.302 2.357 2.412 V 0xF 2.414 2.469 2.525 V Table 18-4. Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 1 VREF Value VIREF Min Ideal VIREF VIREF Max Unit 0x0 0.000 0.000 0.074 V 0x1 0.076 0.149 0.223 V 0x2 0.225 0.298 0.372 V 0x3 0.374 0.448 0.521 V 0x4 0.523 0.597 0.670 V 0x5 0.672 0.746 0.820 V 0x6 0.822 0.895 0.969 V 0x7 0.971 1.044 1.118 V 0x8 1.120 1.193 1.267 V 0x9 1.269 1.343 1.416 V 0xA 1.418 1.492 1.565 V 1064 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 18-4. Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 1 (continued) 18.4 VREF Value VIREF Min Ideal VIREF VIREF Max Unit 0xB 1.567 1.641 1.715 V 0xC 1.717 1.790 1.864 V 0xD 1.866 1.939 2.013 V 0xE 2.015 2.089 2.162 V 0xF 2.164 2.238 2.311 V Initialization and Configuration The following example shows how to configure an analog comparator to read back its output value from an internal register. 1. Enable the analog comparator clock by writing a value of 0x0000.0001 to the RCGCACMP register in the System Control module (see page 333). 2. Enable the clock to the appropriate GPIO modules via the RCGCGPIO register (see page 321). To find out which GPIO ports to enable, refer to Table 20-5 on page 1091. 3. In the GPIO module, enable the GPIO port/pin associated with the input signals as GPIO inputs. To determine which GPIO to configure, see Table 20-4 on page 1087. 4. Configure the PMCn fields in the GPIOPCTL register to assign the analog comparator output signals to the appropriate pins (see page 653 and Table 20-5 on page 1091). 5. Configure the internal voltage reference to 1.65 V by writing the ACREFCTL register with the value 0x0000.030C. 6. Configure the comparator to use the internal voltage reference and to not invert the output by writing the ACCTLn register with the value of 0x0000.040C. 7. Delay for 10 µs. 8. Read the comparator output value by reading the ACSTATn register's OVAL value. Change the level of the comparator negative input signal C- to see the OVAL value change. 18.5 Register Map Table 18-5 on page 1065 lists the comparator registers. The offset listed is a hexadecimal increment to the register's address, relative to the Analog Comparator base address of 0x4003.C000. Note that the analog comparator clock must be enabled before the registers can be programmed (see page 333). There must be a delay of 3 system clocks after the analog comparator module clock is enabled before any analog comparator module registers are accessed. Table 18-5. Analog Comparators Register Map Description See page 0x0000.0000 Analog Comparator Masked Interrupt Status 1067 0x0000.0000 Analog Comparator Raw Interrupt Status 1068 Offset Name Type Reset 0x000 ACMIS RW1C 0x004 ACRIS RO June 12, 2014 1065 Texas Instruments-Production Data Analog Comparators Table 18-5. Analog Comparators Register Map (continued) Description See page 0x0000.0000 Analog Comparator Interrupt Enable 1069 RW 0x0000.0000 Analog Comparator Reference Voltage Control 1070 ACSTAT0 RO 0x0000.0000 Analog Comparator Status 0 1071 0x024 ACCTL0 RW 0x0000.0000 Analog Comparator Control 0 1072 0x040 ACSTAT1 RO 0x0000.0000 Analog Comparator Status 1 1071 0x044 ACCTL1 RW 0x0000.0000 Analog Comparator Control 1 1072 0xFC0 ACMPPP RO 0x0003.0003 Analog Comparator Peripheral Properties 1074 Offset Name Type Reset 0x008 ACINTEN RW 0x010 ACREFCTL 0x020 18.6 Register Descriptions The remainder of this section lists and describes the Analog Comparator registers, in numerical order by address offset. 1066 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 1: Analog Comparator Masked Interrupt Status (ACMIS), offset 0x000 This register provides a summary of the interrupt status (masked) of the comparators. Analog Comparator Masked Interrupt Status (ACMIS) Base 0x4003.C000 Offset 0x000 Type RW1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 IN1 IN0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW1C 0 RW1C 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:2 reserved RO 0x0000.000 1 IN1 RW1C 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Comparator 1 Masked Interrupt Status Value Description 0 No interrupt has occurred or the interrupt is masked. 1 The IN1 bits in the ACRIS register and the ACINTEN registers are set, providing an interrupt to the interrupt controller. This bit is cleared by writing a 1. Clearing this bit also clears the IN1 bit in the ACRIS register. 0 IN0 RW1C 0 Comparator 0 Masked Interrupt Status Value Description 0 No interrupt has occurred or the interrupt is masked. 1 The IN0 bits in the ACRIS register and the ACINTEN registers are set, providing an interrupt to the interrupt controller. This bit is cleared by writing a 1. Clearing this bit also clears the IN0 bit in the ACRIS register. June 12, 2014 1067 Texas Instruments-Production Data Analog Comparators Register 2: Analog Comparator Raw Interrupt Status (ACRIS), offset 0x004 This register provides a summary of the interrupt status (raw) of the comparators. The bits in this register must be enabled to generate interrupts using the ACINTEN register. Analog Comparator Raw Interrupt Status (ACRIS) Base 0x4003.C000 Offset 0x004 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 IN1 IN0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:2 reserved RO 0x0000.000 1 IN1 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Comparator 1 Interrupt Status Value Description 0 An interrupt has not occurred. 1 Comparator 1 has generated an interruptfor an event as configured by the ISEN bit in the ACCTL1 register. This bit is cleared by writing a 1 to the IN1 bit in the ACMIS register. 0 IN0 RO 0 Comparator 0 Interrupt Status Value Description 0 An interrupt has not occurred. 1 Comparator 0 has generated an interrupt for an event as configured by the ISEN bit in the ACCTL0 register. This bit is cleared by writing a 1 to the IN0 bit in the ACMIS register. 1068 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 3: Analog Comparator Interrupt Enable (ACINTEN), offset 0x008 This register provides the interrupt enable for the comparators. Analog Comparator Interrupt Enable (ACINTEN) Base 0x4003.C000 Offset 0x008 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 IN1 IN0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RW 0 RW 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:2 reserved RO 0x00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 IN1 RW 0 Comparator 1 Interrupt Enable Value Description 0 IN0 RW 0 0 A comparator 1 interrupt does not affect the interrupt status. 1 The raw interrupt signal comparator 1 is sent to the interrupt controller. Comparator 0 Interrupt Enable Value Description 0 A comparator 0 interrupt does not affect the interrupt status. 1 The raw interrupt signal comparator 0 is sent to the interrupt controller. June 12, 2014 1069 Texas Instruments-Production Data Analog Comparators Register 4: Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x010 This register specifies whether the resistor ladder is powered on as well as the range and tap. Analog Comparator Reference Voltage Control (ACREFCTL) Base 0x4003.C000 Offset 0x010 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 1 0 RW 0 RW 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 9 8 EN RNG RW 0 RW 0 Bit/Field Name Type Reset 31:10 reserved RO 0x0000.0 9 EN RW 0 reserved RO 0 RO 0 RO 0 VREF RO 0 RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Resistor Ladder Enable Value Description 0 The resistor ladder is unpowered. 1 Powers on the resistor ladder. The resistor ladder is connected to VDDA. This bit is cleared at reset so that the internal reference consumes the least amount of power if it is not used. 8 RNG RW 0 Resistor Ladder Range Value Description 0 The ideal step size for the internal reference is VDDA / 29.4. 1 The ideal step size for the internal reference is VDDA / 22.12. 7:4 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3:0 VREF RW 0x0 Resistor Ladder Voltage Ref The VREF bit field specifies the resistor ladder tap that is passed through an analog multiplexer. The voltage corresponding to the tap position is the internal reference voltage available for comparison. See Table 18-2 on page 1063 for some output reference voltage examples. 1070 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Register 5: Analog Comparator Status 0 (ACSTAT0), offset 0x020 Register 6: Analog Comparator Status 1 (ACSTAT1), offset 0x040 These registers specify the current output value of the comparator. Analog Comparator Status n (ACSTATn) Base 0x4003.C000 Offset 0x020 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 OVAL reserved RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:2 reserved RO 0x0000.000 1 OVAL RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Comparator Output Value Value Description 0 VIN- > VIN+ 1 VIN- < VIN+ VIN - is the voltage on the Cn- pin. VIN+ is the voltage on the Cn+ pin, the C0+ pin, or the internal voltage reference (VIREF) as defined by the ASRCP bit in the ACCTL register. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 12, 2014 1071 Texas Instruments-Production Data Analog Comparators Register 7: Analog Comparator Control 0 (ACCTL0), offset 0x024 Register 8: Analog Comparator Control 1 (ACCTL1), offset 0x044 These registers configure the comparator's input and output. Analog Comparator Control n (ACCTLn) Base 0x4003.C000 Offset 0x024 Type RW, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 reserved TSLVAL CINV reserved RO 0 RW 0 RW 0 RO 0 reserved Type Reset reserved Type Reset TOEN RO 0 RO 0 ASRCP RW 0 RW 0 RW 0 Bit/Field Name Type Reset 31:12 reserved RO 0x0000.0 11 TOEN RW 0 TSEN RW 0 ISLVAL RW 0 RW 0 ISEN RW 0 RW 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Trigger Output Enable Value Description 10:9 ASRCP RW 0x0 0 ADC events are suppressed and not sent to the ADC. 1 ADC events are sent to the ADC. Analog Source Positive The ASRCP field specifies the source of input voltage to the VIN+ terminal of the comparator. The encodings for this field are as follows: Value Description 0x0 Pin value of Cn+ 0x1 Pin value of C0+ 0x2 Internal voltage reference (VIREF) 0x3 Reserved 8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7 TSLVAL RW 0 Trigger Sense Level Value Value Description 0 An ADC event is generated if the comparator output is Low. 1 An ADC event is generated if the comparator output is High. 1072 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Bit/Field Name Type Reset 6:5 TSEN RW 0x0 Description Trigger Sense The TSEN field specifies the sense of the comparator output that generates an ADC event. The sense conditioning is as follows: Value Description 4 ISLVAL RW 0 0x0 Level sense, see TSLVAL 0x1 Falling edge 0x2 Rising edge 0x3 Either edge Interrupt Sense Level Value Value Description 3:2 ISEN RW 0x0 0 An interrupt is generated if the comparator output is Low. 1 An interrupt is generated if the comparator output is High. Interrupt Sense The ISEN field specifies the sense of the comparator output that generates an interrupt. The sense conditioning is as follows: Value Description 1 CINV RW 0 0x0 Level sense, see ISLVAL 0x1 Falling edge 0x2 Rising edge 0x3 Either edge Comparator Output Invert Value Description 0 reserved RO 0 0 The output of the comparator is unchanged. 1 The output of the comparator is inverted prior to being processed by hardware. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 12, 2014 1073 Texas Instruments-Production Data Analog Comparators Register 9: Analog Comparator Peripheral Properties (ACMPPP), offset 0xFC0 The ACMPPP register provides information regarding the properties of the analog comparator module. Analog Comparator Peripheral Properties (ACMPPP) Base 0x4003.C000 Offset 0xFC0 Type RO, reset 0x0003.0003 31 30 29 28 27 26 25 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 24 23 22 21 20 19 18 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset 17 16 C1O C0O RO 1 RO 1 1 0 CMP1 CMP0 RO 1 RO 1 Bit/Field Name Type Reset Description 31:18 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 17 C1O RO 0x1 Comparator Output 1 Present Value Description 16 C0O RO 0x1 0 Comparator output 1 is not present. 1 Comparator output 1 is present. Comparator Output 0 Present Value Description 0 Comparator output 0 is not present. 1 Comparator output 0 is present. 15:2 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 CMP1 RO 0x1 Comparator 1 Present Value Description 0 CMP0 RO 0x1 0 Comparator 1 is not present. 1 Comparator 1 is present. Comparator 0 Present Value Description 0 Comparator 0 is not present. 1 Comparator 0 is present. 1074 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 19 Pin Diagram The TM4C1231H6PM microcontroller pin diagram is shown below. Each GPIO signal is identified by its GPIO port unless it defaults to an alternate function on reset. In this case, the GPIO port name is followed by the default alternate function. To see a complete list of possible functions for each pin, see Table 20-5 on page 1091. Figure 19-1. 64-Pin LQFP Package Pin Diagram June 12, 2014 1075 Texas Instruments-Production Data Signal Tables 20 Signal Tables The following tables list the signals available for each pin. Signals are configured as GPIOs on reset, except for those noted below. Use the GPIOAMSEL register (see page 652) to select analog mode. For a GPIO pin to be used for an alternate digital function, the corresponding bit in the GPIOAFSEL register (see page 636) must be set. Further pin muxing options are provided through the PMCx bit field in the GPIOPCTL register (see page 653), which selects one of several available peripheral functions for that GPIO. Important: Table 10-1 on page 615 shows special consideration GPIO pins. Most GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0). Special consideration pins may be programed to a non-GPIO function or may have special commit controls out of reset. In addition, a Power-On-Reset (POR) or asserting RST returns these GPIO to their original special consideration state. Table 20-1. GPIO Pins With Special Considerations GPIO Pins Default Reset State GPIOAFSEL GPIODEN GPIOPDR GPIOPUR GPIOPCTL GPIOCR PA[1:0] UART0 0 0 0 0 0x1 1 PA[5:2] SSI0 0 0 0 0 0x2 1 PB[3:2] I21C0 0 0 0 0 0x3 1 PC[3:0] JTAG/SWD PD[7] GPIO PF[0] 1 1 0 1 0x1 0 a 0 0 0 0 0x0 0 a 0 0 0 0 0x0 0 GPIO a. This pin is configured as a GPIO by default but is locked and can only be reprogrammed by unlocking the pin in the GPIOLOCK register and uncommitting it by setting the GPIOCR register. Table 20-2 on page 1077 shows the pin-to-signal-name mapping, including functional characteristics of the signals. Each possible alternate analog and digital function is listed for each pin. Table 20-3 on page 1082 lists the signals in alphabetical order by signal name. If it is possible for a signal to be on multiple pins, each possible pin assignment is listed. The "Pin Mux" column indicates the GPIO and the encoding needed in the PMCx bit field in the GPIOPCTL register. Table 20-4 on page 1087 groups the signals by functionality, except for GPIOs. If it is possible for a signal to be on multiple pins, each possible pin assignment is listed. Table 20-5 on page 1091 lists the GPIO pins and their analog and digital alternate functions. The AINx analog signals are not 5-V tolerant and go through an isolation circuit before reaching their circuitry. These signals are configured by clearing the corresponding DEN bit in the GPIO Digital Enable (GPIODEN) register and setting the corresponding AMSEL bit in the GPIO Analog Mode Select (GPIOAMSEL) register. Other analog signals are 5-V tolerant and are connected directly to their circuitry (C0-, C0+, C1-, C1+). These signals are configured by clearing the DEN bit in the GPIO Digital Enable (GPIODEN) register. The digital signals are enabled by setting the appropriate bit in the GPIO Alternate Function Select (GPIOAFSEL) and GPIODEN registers and configuring the PMCx bit field in the GPIO Port Control (GPIOPCTL) register to the numeric enoding shown in the table below. Table entries that are shaded gray are the default values for the corresponding GPIO pin. 1076 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-6 on page 1093 lists the signals based on number of possible pin assignments. This table can be used to plan how to configure the pins for a particular functionality. Application Note AN01274 Configuring Tiva™ C Series Microcontrollers with Pin Multiplexing provides an overview of the pin muxing implementation, an explanation of how a system designer defines a pin configuration, and examples of the pin configuration process. Note: 20.1 All digital inputs are Schmitt triggered. Signals by Pin Number Table 20-2. Signals by Pin Number Pin Number 1 a Pin Name Pin Type Buffer Type PB6 I/O TTL GPIO port B bit 6. SSI2Rx I TTL SSI module 2 receive. T0CCP0 I/O TTL 16/32-Bit Timer 0 Capture/Compare/PWM 0. VDDA - Power The positive supply for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. VDDA pins must be supplied with a voltage that meets the specification in Table 21-5 on page 1098, regardless of system implementation. GNDA - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. PB7 I/O TTL GPIO port B bit 7. SSI2Tx O TTL SSI module 2 transmit. T0CCP1 I/O TTL 16/32-Bit Timer 0 Capture/Compare/PWM 1. 2 3 4 PF4 I/O TTL GPIO port F bit 4. T2CCP0 I/O TTL 16/32-Bit Timer 2 Capture/Compare/PWM 0. PE3 I/O TTL GPIO port E bit 3. AIN0 I Analog PE2 I/O TTL AIN1 I Analog PE1 I/O TTL AIN2 I Analog U7Tx O TTL UART module 7 transmit. PE0 I/O TTL GPIO port E bit 0. AIN3 I Analog U7Rx I TTL UART module 7 receive. PD7 I/O TTL GPIO port D bit 7. 5 6 7 8 9 Description Analog-to-digital converter input 0. GPIO port E bit 2. Analog-to-digital converter input 1. GPIO port E bit 1. Analog-to-digital converter input 2. Analog-to-digital converter input 3. NMI I TTL Non-maskable interrupt. U2Tx O TTL UART module 2 transmit. WT5CCP1 I/O TTL 32/64-Bit Wide Timer 5 Capture/Compare/PWM 1. 11 VDD - Power Positive supply for I/O and some logic. 12 GND - Power Ground reference for logic and I/O pins. 10 June 12, 2014 1077 Texas Instruments-Production Data Signal Tables Table 20-2. Signals by Pin Number (continued) Pin Number Pin Type PC7 I/O TTL C0- I Analog U3Tx O TTL UART module 3 transmit. WT1CCP1 I/O TTL 32/64-Bit Wide Timer 1 Capture/Compare/PWM 1. PC6 I/O TTL GPIO port C bit 6. 13 Buffer Type GPIO port C bit 7. Analog comparator 0 negative input. C0+ I Analog I TTL UART module 3 receive. WT1CCP0 I/O TTL 32/64-Bit Wide Timer 1 Capture/Compare/PWM 0. PC5 I/O TTL GPIO port C bit 5. C1+ I Analog U1CTS I TTL UART module 1 Clear To Send modem flow control input signal. U1Tx O TTL UART module 1 transmit. U4Tx O TTL UART module 4 transmit. WT0CCP1 I/O TTL 32/64-Bit Wide Timer 0 Capture/Compare/PWM 1. PC4 I/O TTL GPIO port C bit 4. 15 Analog comparator 0 positive input. Analog comparator 1 positive input. C1- I Analog U1RTS O TTL UART module 1 Request to Send modem flow control output line. U1Rx I TTL UART module 1 receive. 16 Analog comparator 1 negative input. U4Rx I TTL UART module 4 receive. WT0CCP0 I/O TTL 32/64-Bit Wide Timer 0 Capture/Compare/PWM 0. PA0 I/O TTL GPIO port A bit 0. U0Rx I TTL UART module 0 receive. PA1 I/O TTL GPIO port A bit 1. U0Tx O TTL UART module 0 transmit. PA2 I/O TTL GPIO port A bit 2. SSI0Clk I/O TTL SSI module 0 clock 17 18 19 PA3 I/O TTL GPIO port A bit 3. SSI0Fss I/O TTL SSI module 0 frame signal 20 PA4 I/O TTL GPIO port A bit 4. SSI0Rx I TTL SSI module 0 receive PA5 I/O TTL GPIO port A bit 5. SSI0Tx O TTL SSI module 0 transmit PA6 I/O TTL GPIO port A bit 6. I2C1SCL I/O OD I2C module 1 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. PA7 I/O TTL GPIO port A bit 7. I2C1SDA I/O OD I2C module 1 data. VDDC - Power Positive supply for most of the logic function, including the processor core and most peripherals. The voltage on this pin is 1.2 V and is supplied by the on-chip LDO. The VDDC pins should only be connected to each other and an external capacitor as specified in Table 21-12 on page 1111 . VDD - Power Positive supply for I/O and some logic. 21 22 24 25 26 Description U3Rx 14 23 a Pin Name 1078 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-2. Signals by Pin Number (continued) Pin Number Pin Name 27 28 Buffer Type GND - Power PF0 I/O TTL GPIO port F bit 0. C0o O TTL Analog comparator 0 output. CAN0Rx I TTL CAN module 0 receive. NMI I TTL Non-maskable interrupt. SSI1Rx I TTL SSI module 1 receive. T0CCP0 I/O TTL 16/32-Bit Timer 0 Capture/Compare/PWM 0. U1RTS O TTL UART module 1 Request to Send modem flow control output line. PF1 I/O TTL GPIO port F bit 1. C1o O TTL Analog comparator 1 output. SSI1Tx O TTL SSI module 1 transmit. T0CCP1 I/O TTL 16/32-Bit Timer 0 Capture/Compare/PWM 1. TRD1 O TTL Trace data 1. U1CTS I TTL UART module 1 Clear To Send modem flow control input signal. PF2 I/O TTL GPIO port F bit 2. SSI1Clk I/O TTL SSI module 1 clock. T1CCP0 I/O TTL 16/32-Bit Timer 1 Capture/Compare/PWM 0. TRD0 O TTL Trace data 0. 29 30 31 32 33 a Pin Type Ground reference for logic and I/O pins. PF3 I/O TTL GPIO port F bit 3. CAN0Tx O TTL CAN module 0 transmit. SSI1Fss I/O TTL SSI module 1 frame signal. T1CCP1 I/O TTL 16/32-Bit Timer 1 Capture/Compare/PWM 1. TRCLK O TTL Trace clock. WAKE I TTL An external input that brings the processor out of Hibernate mode when asserted. An output that indicates the processor is in Hibernate mode. HIB O TTL XOSC0 I Analog Hibernation module oscillator crystal input or an external clock reference input. Note that this is either a 32.768-kHz crystal or a 32.768-kHz oscillator for the Hibernation module RTC. GNDX - Power GND for the Hibernation oscillator. When using a crystal clock source, this pin should be connected to digital ground along with the crystal load capacitors. When using an external oscillator, this pin should be connected to digital ground. XOSC1 O Analog Hibernation module oscillator crystal output. Leave unconnected when using a single-ended clock source. VBAT - Power Power source for the Hibernation module. It is normally connected to the positive terminal of a battery and serves as the battery backup/Hibernation module power-source supply. 34 35 36 Description 37 38 RST I TTL 39 GND - Power Ground reference for logic and I/O pins. 40 OSC0 I Analog Main oscillator crystal input or an external clock reference input. OSC1 O Analog Main oscillator crystal output. Leave unconnected when using a single-ended clock source. VDD - Power Positive supply for I/O and some logic. 41 42 System reset input. June 12, 2014 1079 Texas Instruments-Production Data Signal Tables Table 20-2. Signals by Pin Number (continued) a Pin Number Pin Name Pin Type Buffer Type PD4 I/O TTL GPIO port D bit 4. This pin is not 5-V tolerant. 43 U6Rx I TTL UART module 6 receive. WT4CCP0 I/O TTL 32/64-Bit Wide Timer 4 Capture/Compare/PWM 0. 44 45 46 47 48 PD5 I/O TTL GPIO port D bit 5. This pin is not 5-V tolerant. U6Tx O TTL UART module 6 transmit. WT4CCP1 I/O TTL 32/64-Bit Wide Timer 4 Capture/Compare/PWM 1. PB0 I/O TTL GPIO port B bit 0. This pin is not 5-V tolerant. T2CCP0 I/O TTL 16/32-Bit Timer 2 Capture/Compare/PWM 0. U1Rx I TTL UART module 1 receive. PB1 I/O TTL GPIO port B bit 1. This pin is not 5-V tolerant. T2CCP1 I/O TTL 16/32-Bit Timer 2 Capture/Compare/PWM 1. U1Tx O TTL UART module 1 transmit. PB2 I/O TTL GPIO port B bit 2. I2C0SCL I/O OD I2C module 0 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. T3CCP0 I/O TTL 16/32-Bit Timer 3 Capture/Compare/PWM 0. PB3 I/O TTL GPIO port B bit 3. I2C0SDA I/O OD I2C module 0 data. T3CCP1 I/O TTL 16/32-Bit Timer 3 Capture/Compare/PWM 1. PC3 I/O TTL GPIO port C bit 3. SWO O TTL JTAG TDO and SWO. T5CCP1 I/O TTL 16/32-Bit Timer 5 Capture/Compare/PWM 1. TDO O TTL JTAG TDO and SWO. 49 50 PC2 I/O TTL GPIO port C bit 2. T5CCP0 I/O TTL 16/32-Bit Timer 5 Capture/Compare/PWM 0. TDI I TTL JTAG TDI. PC1 I/O TTL GPIO port C bit 1. SWDIO I/O TTL JTAG TMS and SWDIO. T4CCP1 I/O TTL 16/32-Bit Timer 4 Capture/Compare/PWM 1. TMS I TTL JTAG TMS and SWDIO. PC0 I/O TTL GPIO port C bit 0. 51 SWCLK I TTL JTAG/SWD CLK. T4CCP0 I/O TTL 16/32-Bit Timer 4 Capture/Compare/PWM 0. TCK I TTL JTAG/SWD CLK. 52 53 Description PD6 I/O TTL GPIO port D bit 6. U2Rx I TTL UART module 2 receive. 32/64-Bit Wide Timer 5 Capture/Compare/PWM 0. WT5CCP0 I/O TTL 54 VDD - Power Positive supply for I/O and some logic. 55 GND - Power Ground reference for logic and I/O pins. 1080 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-2. Signals by Pin Number (continued) Pin Number a Pin Name Pin Type Buffer Type VDDC - Power PB5 I/O TTL AIN11 I Analog 56 57 58 59 60 Description Positive supply for most of the logic function, including the processor core and most peripherals. The voltage on this pin is 1.2 V and is supplied by the on-chip LDO. The VDDC pins should only be connected to each other and an external capacitor as specified in Table 21-12 on page 1111 . GPIO port B bit 5. Analog-to-digital converter input 11. CAN0Tx O TTL CAN module 0 transmit. SSI2Fss I/O TTL SSI module 2 frame signal. T1CCP1 I/O TTL 16/32-Bit Timer 1 Capture/Compare/PWM 1. PB4 I/O TTL GPIO port B bit 4. AIN10 I Analog Analog-to-digital converter input 10. CAN0Rx I TTL CAN module 0 receive. SSI2Clk I/O TTL SSI module 2 clock. T1CCP0 I/O TTL 16/32-Bit Timer 1 Capture/Compare/PWM 0. PE4 I/O TTL GPIO port E bit 4. AIN9 I Analog Analog-to-digital converter input 9. CAN0Rx I TTL CAN module 0 receive. I2C2SCL I/O OD I2C module 2 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. U5Rx I TTL UART module 5 receive. PE5 I/O TTL GPIO port E bit 5. AIN8 I Analog CAN0Tx O TTL Analog-to-digital converter input 8. CAN module 0 transmit. I2C2SDA I/O OD I2C module 2 data. U5Tx O TTL UART module 5 transmit. PD0 I/O TTL GPIO port D bit 0. AIN7 I Analog I2C3SCL I/O OD I2C module 3 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. SSI1Clk I/O TTL SSI module 1 clock. SSI3Clk I/O TTL SSI module 3 clock. WT2CCP0 I/O TTL 32/64-Bit Wide Timer 2 Capture/Compare/PWM 0. PD1 I/O TTL GPIO port D bit 1. AIN6 I Analog I2C3SDA I/O OD I2C module 3 data. SSI1Fss I/O TTL SSI module 1 frame signal. SSI3Fss I/O TTL SSI module 3 frame signal. WT2CCP1 I/O TTL 32/64-Bit Wide Timer 2 Capture/Compare/PWM 1. 61 62 Analog-to-digital converter input 7. Analog-to-digital converter input 6. June 12, 2014 1081 Texas Instruments-Production Data Signal Tables Table 20-2. Signals by Pin Number (continued) Pin Number 63 64 Pin Name Pin Type a Buffer Type Description PD2 I/O TTL AIN5 I Analog GPIO port D bit 2. SSI1Rx I TTL SSI module 1 receive. Analog-to-digital converter input 5. SSI3Rx I TTL SSI module 3 receive. WT3CCP0 I/O TTL 32/64-Bit Wide Timer 3 Capture/Compare/PWM 0. GPIO port D bit 3. PD3 I/O TTL AIN4 I Analog SSI1Tx O TTL SSI module 1 transmit. SSI3Tx O TTL SSI module 3 transmit. WT3CCP1 I/O TTL 32/64-Bit Wide Timer 3 Capture/Compare/PWM 1. Analog-to-digital converter input 4. a. The TTL designation indicates the pin has TTL-compatible voltage levels. 20.2 Signals by Signal Name Table 20-3. Signals by Signal Name Pin Name Pin Number Pin Mux / Pin Assignment a Pin Type Buffer Type Description AIN0 6 PE3 I Analog Analog-to-digital converter input 0. AIN1 7 PE2 I Analog Analog-to-digital converter input 1. AIN2 8 PE1 I Analog Analog-to-digital converter input 2. AIN3 9 PE0 I Analog Analog-to-digital converter input 3. AIN4 64 PD3 I Analog Analog-to-digital converter input 4. AIN5 63 PD2 I Analog Analog-to-digital converter input 5. AIN6 62 PD1 I Analog Analog-to-digital converter input 6. AIN7 61 PD0 I Analog Analog-to-digital converter input 7. AIN8 60 PE5 I Analog Analog-to-digital converter input 8. AIN9 59 PE4 I Analog Analog-to-digital converter input 9. AIN10 58 PB4 I Analog Analog-to-digital converter input 10. AIN11 57 PB5 I Analog Analog-to-digital converter input 11. C0+ 14 PC6 I Analog Analog comparator 0 positive input. C0- 13 PC7 I Analog Analog comparator 0 negative input. C0o 28 PF0 (9) O TTL C1+ 15 PC5 I Analog Analog comparator 1 positive input. C1- 16 PC4 I Analog Analog comparator 1 negative input. C1o 29 PF1 (9) O TTL Analog comparator 1 output. CAN0Rx 28 58 59 PF0 (3) PB4 (8) PE4 (8) I TTL CAN module 0 receive. CAN0Tx 31 57 60 PF3 (3) PB5 (8) PE5 (8) O TTL CAN module 0 transmit. Analog comparator 0 output. 1082 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-3. Signals by Signal Name (continued) Pin Name Pin Number Pin Mux / Pin Assignment a Pin Type Buffer Type Description GND 12 27 39 55 fixed - Power Ground reference for logic and I/O pins. GNDA 3 fixed - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. GNDX 35 fixed - Power GND for the Hibernation oscillator. When using a crystal clock source, this pin should be connected to digital ground along with the crystal load capacitors. When using an external oscillator, this pin should be connected to digital ground. HIB 33 fixed O TTL An output that indicates the processor is in Hibernate mode. I2C0SCL 47 PB2 (3) I/O OD I2C module 0 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C0SDA 48 PB3 (3) I/O OD I2C module 0 data. I2C1SCL 23 PA6 (3) I/O OD I2C module 1 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C1SDA 24 PA7 (3) I/O OD I2C module 1 data. I2C2SCL 59 PE4 (3) I/O OD I2C module 2 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C2SDA 60 PE5 (3) I/O OD I2C module 2 data. I2C3SCL 61 PD0 (3) I/O OD I2C module 3 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C3SDA 62 PD1 (3) I/O OD I2C module 3 data. NMI 10 28 PD7 (8) PF0 (8) I TTL Non-maskable interrupt. OSC0 40 fixed I Analog Main oscillator crystal input or an external clock reference input. OSC1 41 fixed O Analog Main oscillator crystal output. Leave unconnected when using a single-ended clock source. PA0 17 - I/O TTL GPIO port A bit 0. PA1 18 - I/O TTL GPIO port A bit 1. PA2 19 - I/O TTL GPIO port A bit 2. PA3 20 - I/O TTL GPIO port A bit 3. PA4 21 - I/O TTL GPIO port A bit 4. PA5 22 - I/O TTL GPIO port A bit 5. PA6 23 - I/O TTL GPIO port A bit 6. PA7 24 - I/O TTL GPIO port A bit 7. PB0 45 - I/O TTL GPIO port B bit 0. This pin is not 5-V tolerant. PB1 46 - I/O TTL GPIO port B bit 1. This pin is not 5-V tolerant. June 12, 2014 1083 Texas Instruments-Production Data Signal Tables Table 20-3. Signals by Signal Name (continued) Pin Name PB2 Pin Number Pin Mux / Pin Assignment 47 - a Pin Type Buffer Type I/O TTL Description GPIO port B bit 2. PB3 48 - I/O TTL GPIO port B bit 3. PB4 58 - I/O TTL GPIO port B bit 4. PB5 57 - I/O TTL GPIO port B bit 5. PB6 1 - I/O TTL GPIO port B bit 6. PB7 4 - I/O TTL GPIO port B bit 7. PC0 52 - I/O TTL GPIO port C bit 0. PC1 51 - I/O TTL GPIO port C bit 1. PC2 50 - I/O TTL GPIO port C bit 2. PC3 49 - I/O TTL GPIO port C bit 3. PC4 16 - I/O TTL GPIO port C bit 4. PC5 15 - I/O TTL GPIO port C bit 5. PC6 14 - I/O TTL GPIO port C bit 6. PC7 13 - I/O TTL GPIO port C bit 7. PD0 61 - I/O TTL GPIO port D bit 0. PD1 62 - I/O TTL GPIO port D bit 1. PD2 63 - I/O TTL GPIO port D bit 2. PD3 64 - I/O TTL GPIO port D bit 3. PD4 43 - I/O TTL GPIO port D bit 4. This pin is not 5-V tolerant. PD5 44 - I/O TTL GPIO port D bit 5. This pin is not 5-V tolerant. PD6 53 - I/O TTL GPIO port D bit 6. PD7 10 - I/O TTL GPIO port D bit 7. PE0 9 - I/O TTL GPIO port E bit 0. PE1 8 - I/O TTL GPIO port E bit 1. PE2 7 - I/O TTL GPIO port E bit 2. PE3 6 - I/O TTL GPIO port E bit 3. PE4 59 - I/O TTL GPIO port E bit 4. PE5 60 - I/O TTL GPIO port E bit 5. PF0 28 - I/O TTL GPIO port F bit 0. PF1 29 - I/O TTL GPIO port F bit 1. PF2 30 - I/O TTL GPIO port F bit 2. PF3 31 - I/O TTL GPIO port F bit 3. PF4 5 - I/O TTL GPIO port F bit 4. RST 38 fixed I TTL System reset input. SSI0Clk 19 PA2 (2) I/O TTL SSI module 0 clock SSI0Fss 20 PA3 (2) I/O TTL SSI module 0 frame signal SSI0Rx 21 PA4 (2) I TTL SSI module 0 receive SSI0Tx 22 PA5 (2) O TTL SSI module 0 transmit SSI1Clk 30 61 PF2 (2) PD0 (2) I/O TTL SSI module 1 clock. 1084 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-3. Signals by Signal Name (continued) Pin Name Pin Number Pin Mux / Pin Assignment a Pin Type Buffer Type Description SSI1Fss 31 62 PF3 (2) PD1 (2) I/O TTL SSI module 1 frame signal. SSI1Rx 28 63 PF0 (2) PD2 (2) I TTL SSI module 1 receive. SSI1Tx 29 64 PF1 (2) PD3 (2) O TTL SSI module 1 transmit. SSI2Clk 58 PB4 (2) I/O TTL SSI module 2 clock. SSI2Fss 57 PB5 (2) I/O TTL SSI module 2 frame signal. SSI2Rx 1 PB6 (2) I TTL SSI module 2 receive. SSI2Tx 4 PB7 (2) O TTL SSI module 2 transmit. SSI3Clk 61 PD0 (1) I/O TTL SSI module 3 clock. SSI3Fss 62 PD1 (1) I/O TTL SSI module 3 frame signal. SSI3Rx 63 PD2 (1) I TTL SSI module 3 receive. SSI3Tx 64 PD3 (1) O TTL SSI module 3 transmit. SWCLK 52 PC0 (1) I TTL JTAG/SWD CLK. SWDIO 51 PC1 (1) I/O TTL JTAG TMS and SWDIO. SWO 49 PC3 (1) O TTL JTAG TDO and SWO. T0CCP0 1 28 PB6 (7) PF0 (7) I/O TTL 16/32-Bit Timer 0 Capture/Compare/PWM 0. T0CCP1 4 29 PB7 (7) PF1 (7) I/O TTL 16/32-Bit Timer 0 Capture/Compare/PWM 1. T1CCP0 30 58 PF2 (7) PB4 (7) I/O TTL 16/32-Bit Timer 1 Capture/Compare/PWM 0. T1CCP1 31 57 PF3 (7) PB5 (7) I/O TTL 16/32-Bit Timer 1 Capture/Compare/PWM 1. T2CCP0 5 45 PF4 (7) PB0 (7) I/O TTL 16/32-Bit Timer 2 Capture/Compare/PWM 0. T2CCP1 46 PB1 (7) I/O TTL 16/32-Bit Timer 2 Capture/Compare/PWM 1. T3CCP0 47 PB2 (7) I/O TTL 16/32-Bit Timer 3 Capture/Compare/PWM 0. T3CCP1 48 PB3 (7) I/O TTL 16/32-Bit Timer 3 Capture/Compare/PWM 1. T4CCP0 52 PC0 (7) I/O TTL 16/32-Bit Timer 4 Capture/Compare/PWM 0. T4CCP1 51 PC1 (7) I/O TTL 16/32-Bit Timer 4 Capture/Compare/PWM 1. T5CCP0 50 PC2 (7) I/O TTL 16/32-Bit Timer 5 Capture/Compare/PWM 0. T5CCP1 49 PC3 (7) I/O TTL 16/32-Bit Timer 5 Capture/Compare/PWM 1. TCK 52 PC0 (1) I TTL JTAG/SWD CLK. TDI 50 PC2 (1) I TTL JTAG TDI. TDO 49 PC3 (1) O TTL JTAG TDO and SWO. TMS 51 PC1 (1) I TTL JTAG TMS and SWDIO. TRCLK 31 PF3 (14) O TTL Trace clock. TRD0 30 PF2 (14) O TTL Trace data 0. TRD1 29 PF1 (14) O TTL Trace data 1. U0Rx 17 PA0 (1) I TTL UART module 0 receive. U0Tx 18 PA1 (1) O TTL UART module 0 transmit. June 12, 2014 1085 Texas Instruments-Production Data Signal Tables Table 20-3. Signals by Signal Name (continued) Pin Name Pin Number Pin Mux / Pin Assignment a Pin Type Buffer Type Description U1CTS 15 29 PC5 (8) PF1 (1) I TTL UART module 1 Clear To Send modem flow control input signal. U1RTS 16 28 PC4 (8) PF0 (1) O TTL UART module 1 Request to Send modem flow control output line. U1Rx 16 45 PC4 (2) PB0 (1) I TTL UART module 1 receive. U1Tx 15 46 PC5 (2) PB1 (1) O TTL UART module 1 transmit. U2Rx 53 PD6 (1) I TTL UART module 2 receive. U2Tx 10 PD7 (1) O TTL UART module 2 transmit. U3Rx 14 PC6 (1) I TTL UART module 3 receive. U3Tx 13 PC7 (1) O TTL UART module 3 transmit. U4Rx 16 PC4 (1) I TTL UART module 4 receive. U4Tx 15 PC5 (1) O TTL UART module 4 transmit. U5Rx 59 PE4 (1) I TTL UART module 5 receive. U5Tx 60 PE5 (1) O TTL UART module 5 transmit. U6Rx 43 PD4 (1) I TTL UART module 6 receive. U6Tx 44 PD5 (1) O TTL UART module 6 transmit. U7Rx 9 PE0 (1) I TTL UART module 7 receive. U7Tx 8 PE1 (1) O TTL UART module 7 transmit. VBAT 37 fixed - Power Power source for the Hibernation module. It is normally connected to the positive terminal of a battery and serves as the battery backup/Hibernation module power-source supply. VDD 11 26 42 54 fixed - Power Positive supply for I/O and some logic. VDDA 2 fixed - Power The positive supply for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. VDDA pins must be supplied with a voltage that meets the specification in Table 21-5 on page 1098, regardless of system implementation. VDDC 25 56 fixed - Power Positive supply for most of the logic function, including the processor core and most peripherals. The voltage on this pin is 1.2 V and is supplied by the on-chip LDO. The VDDC pins should only be connected to each other and an external capacitor as specified in Table 21-12 on page 1111 . WAKE 32 fixed I TTL An external input that brings the processor out of Hibernate mode when asserted. WT0CCP0 16 PC4 (7) I/O TTL 32/64-Bit Wide Timer 0 Capture/Compare/PWM 0. WT0CCP1 15 PC5 (7) I/O TTL 32/64-Bit Wide Timer 0 Capture/Compare/PWM 1. WT1CCP0 14 PC6 (7) I/O TTL 32/64-Bit Wide Timer 1 Capture/Compare/PWM 0. WT1CCP1 13 PC7 (7) I/O TTL 32/64-Bit Wide Timer 1 Capture/Compare/PWM 1. 1086 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-3. Signals by Signal Name (continued) Pin Name Pin Number Pin Mux / Pin Assignment 61 WT2CCP0 PD0 (7) a Pin Type Buffer Type I/O TTL Description 32/64-Bit Wide Timer 2 Capture/Compare/PWM 0. WT2CCP1 62 PD1 (7) I/O TTL 32/64-Bit Wide Timer 2 Capture/Compare/PWM 1. WT3CCP0 63 PD2 (7) I/O TTL 32/64-Bit Wide Timer 3 Capture/Compare/PWM 0. WT3CCP1 64 PD3 (7) I/O TTL 32/64-Bit Wide Timer 3 Capture/Compare/PWM 1. WT4CCP0 43 PD4 (7) I/O TTL 32/64-Bit Wide Timer 4 Capture/Compare/PWM 0. WT4CCP1 44 PD5 (7) I/O TTL 32/64-Bit Wide Timer 4 Capture/Compare/PWM 1. WT5CCP0 53 PD6 (7) I/O TTL 32/64-Bit Wide Timer 5 Capture/Compare/PWM 0. WT5CCP1 10 PD7 (7) I/O TTL 32/64-Bit Wide Timer 5 Capture/Compare/PWM 1. XOSC0 34 fixed I Analog Hibernation module oscillator crystal input or an external clock reference input. Note that this is either a 32.768-kHz crystal or a 32.768-kHz oscillator for the Hibernation module RTC. XOSC1 36 fixed O Analog Hibernation module oscillator crystal output. Leave unconnected when using a single-ended clock source. a. The TTL designation indicates the pin has TTL-compatible voltage levels. 20.3 Signals by Function, Except for GPIO Table 20-4. Signals by Function, Except for GPIO Function Pin Name a Pin Number Pin Type Buffer Type AIN0 6 I Analog Analog-to-digital converter input 0. AIN1 7 I Analog Analog-to-digital converter input 1. AIN2 8 I Analog Analog-to-digital converter input 2. AIN3 9 I Analog Analog-to-digital converter input 3. AIN4 64 I Analog Analog-to-digital converter input 4. AIN5 63 I Analog Analog-to-digital converter input 5. AIN6 62 I Analog Analog-to-digital converter input 6. AIN7 61 I Analog Analog-to-digital converter input 7. AIN8 60 I Analog Analog-to-digital converter input 8. AIN9 59 I Analog Analog-to-digital converter input 9. AIN10 58 I Analog Analog-to-digital converter input 10. AIN11 57 I Analog Analog-to-digital converter input 11. C0+ 14 I Analog Analog comparator 0 positive input. C0- 13 I Analog Analog comparator 0 negative input. C0o 28 O TTL C1+ 15 I Analog Analog comparator 1 positive input. C1- 16 I Analog Analog comparator 1 negative input. C1o 29 O TTL ADC Analog Comparators Description Analog comparator 0 output. Analog comparator 1 output. June 12, 2014 1087 Texas Instruments-Production Data Signal Tables Table 20-4. Signals by Function, Except for GPIO (continued) Function Controller Area Network Core General-Purpose Timers Pin Name a Pin Number Pin Type Buffer Type Description CAN0Rx 28 58 59 I TTL CAN module 0 receive. CAN0Tx 31 57 60 O TTL CAN module 0 transmit. TRCLK 31 O TTL Trace clock. TRD0 30 O TTL Trace data 0. TRD1 29 O TTL Trace data 1. T0CCP0 1 28 I/O TTL 16/32-Bit Timer 0 Capture/Compare/PWM 0. T0CCP1 4 29 I/O TTL 16/32-Bit Timer 0 Capture/Compare/PWM 1. T1CCP0 30 58 I/O TTL 16/32-Bit Timer 1 Capture/Compare/PWM 0. T1CCP1 31 57 I/O TTL 16/32-Bit Timer 1 Capture/Compare/PWM 1. T2CCP0 5 45 I/O TTL 16/32-Bit Timer 2 Capture/Compare/PWM 0. T2CCP1 46 I/O TTL 16/32-Bit Timer 2 Capture/Compare/PWM 1. T3CCP0 47 I/O TTL 16/32-Bit Timer 3 Capture/Compare/PWM 0. T3CCP1 48 I/O TTL 16/32-Bit Timer 3 Capture/Compare/PWM 1. T4CCP0 52 I/O TTL 16/32-Bit Timer 4 Capture/Compare/PWM 0. T4CCP1 51 I/O TTL 16/32-Bit Timer 4 Capture/Compare/PWM 1. T5CCP0 50 I/O TTL 16/32-Bit Timer 5 Capture/Compare/PWM 0. T5CCP1 49 I/O TTL 16/32-Bit Timer 5 Capture/Compare/PWM 1. WT0CCP0 16 I/O TTL 32/64-Bit Wide Timer 0 Capture/Compare/PWM 0. WT0CCP1 15 I/O TTL 32/64-Bit Wide Timer 0 Capture/Compare/PWM 1. WT1CCP0 14 I/O TTL 32/64-Bit Wide Timer 1 Capture/Compare/PWM 0. WT1CCP1 13 I/O TTL 32/64-Bit Wide Timer 1 Capture/Compare/PWM 1. WT2CCP0 61 I/O TTL 32/64-Bit Wide Timer 2 Capture/Compare/PWM 0. WT2CCP1 62 I/O TTL 32/64-Bit Wide Timer 2 Capture/Compare/PWM 1. WT3CCP0 63 I/O TTL 32/64-Bit Wide Timer 3 Capture/Compare/PWM 0. WT3CCP1 64 I/O TTL 32/64-Bit Wide Timer 3 Capture/Compare/PWM 1. WT4CCP0 43 I/O TTL 32/64-Bit Wide Timer 4 Capture/Compare/PWM 0. WT4CCP1 44 I/O TTL 32/64-Bit Wide Timer 4 Capture/Compare/PWM 1. WT5CCP0 53 I/O TTL 32/64-Bit Wide Timer 5 Capture/Compare/PWM 0. WT5CCP1 10 I/O TTL 32/64-Bit Wide Timer 5 Capture/Compare/PWM 1. 1088 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-4. Signals by Function, Except for GPIO (continued) Function Pin Name a Pin Number Pin Type Buffer Type Description GNDX 35 - Power GND for the Hibernation oscillator. When using a crystal clock source, this pin should be connected to digital ground along with the crystal load capacitors. When using an external oscillator, this pin should be connected to digital ground. HIB 33 O TTL VBAT 37 - Power Power source for the Hibernation module. It is normally connected to the positive terminal of a battery and serves as the battery backup/Hibernation module power-source supply. WAKE 32 I TTL An external input that brings the processor out of Hibernate mode when asserted. XOSC0 34 I Analog Hibernation module oscillator crystal input or an external clock reference input. Note that this is either a 32.768-kHz crystal or a 32.768-kHz oscillator for the Hibernation module RTC. XOSC1 36 O Analog Hibernation module oscillator crystal output. Leave unconnected when using a single-ended clock source. I2C0SCL 47 I/O OD I2C module 0 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C0SDA 48 I/O OD I2C module 0 data. I2C1SCL 23 I/O OD I2C module 1 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C1SDA 24 I/O OD I2C module 1 data. I2C2SCL 59 I/O OD I2C module 2 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C2SDA 60 I/O OD I2C module 2 data. I2C3SCL 61 I/O OD I2C module 3 clock. Note that this signal has an active pull-up. The corresponding port pin should not be configured as open drain. I2C3SDA 62 I/O OD I2C module 3 data. SWCLK 52 I TTL JTAG/SWD CLK. SWDIO 51 I/O TTL JTAG TMS and SWDIO. SWO 49 O TTL JTAG TDO and SWO. TCK 52 I TTL JTAG/SWD CLK. TDI 50 I TTL JTAG TDI. TDO 49 O TTL JTAG TDO and SWO. TMS 51 I TTL JTAG TMS and SWDIO. Hibernate I2C JTAG/SWD/SWO An output that indicates the processor is in Hibernate mode. June 12, 2014 1089 Texas Instruments-Production Data Signal Tables Table 20-4. Signals by Function, Except for GPIO (continued) Function Power SSI Pin Name a Pin Number Pin Type Buffer Type Description GND 12 27 39 55 - Power Ground reference for logic and I/O pins. GNDA 3 - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. VDD 11 26 42 54 - Power Positive supply for I/O and some logic. VDDA 2 - Power The positive supply for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. VDDA pins must be supplied with a voltage that meets the specification in Table 21-5 on page 1098, regardless of system implementation. VDDC 25 56 - Power Positive supply for most of the logic function, including the processor core and most peripherals. The voltage on this pin is 1.2 V and is supplied by the on-chip LDO. The VDDC pins should only be connected to each other and an external capacitor as specified in Table 21-12 on page 1111 . SSI0Clk 19 I/O TTL SSI module 0 clock SSI0Fss 20 I/O TTL SSI module 0 frame signal SSI0Rx 21 I TTL SSI module 0 receive SSI0Tx 22 O TTL SSI module 0 transmit SSI1Clk 30 61 I/O TTL SSI module 1 clock. SSI1Fss 31 62 I/O TTL SSI module 1 frame signal. SSI1Rx 28 63 I TTL SSI module 1 receive. SSI1Tx 29 64 O TTL SSI module 1 transmit. SSI2Clk 58 I/O TTL SSI module 2 clock. SSI2Fss 57 I/O TTL SSI module 2 frame signal. SSI2Rx 1 I TTL SSI module 2 receive. SSI2Tx 4 O TTL SSI module 2 transmit. SSI3Clk 61 I/O TTL SSI module 3 clock. SSI3Fss 62 I/O TTL SSI module 3 frame signal. SSI3Rx 63 I TTL SSI module 3 receive. SSI3Tx 64 O TTL SSI module 3 transmit. 1090 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-4. Signals by Function, Except for GPIO (continued) Function Pin Name Pin Type Buffer Type NMI 10 28 I TTL OSC0 40 I Analog Main oscillator crystal input or an external clock reference input. OSC1 41 O Analog Main oscillator crystal output. Leave unconnected when using a single-ended clock source. RST 38 I TTL System reset input. U0Rx 17 I TTL UART module 0 receive. U0Tx 18 O TTL UART module 0 transmit. U1CTS 15 29 I TTL UART module 1 Clear To Send modem flow control input signal. U1RTS 16 28 O TTL UART module 1 Request to Send modem flow control output line. U1Rx 16 45 I TTL UART module 1 receive. U1Tx 15 46 O TTL UART module 1 transmit. U2Rx 53 I TTL UART module 2 receive. U2Tx 10 O TTL UART module 2 transmit. U3Rx 14 I TTL UART module 3 receive. U3Tx 13 O TTL UART module 3 transmit. U4Rx 16 I TTL UART module 4 receive. U4Tx 15 O TTL UART module 4 transmit. U5Rx 59 I TTL UART module 5 receive. U5Tx 60 O TTL UART module 5 transmit. U6Rx 43 I TTL UART module 6 receive. U6Tx 44 O TTL UART module 6 transmit. U7Rx 9 I TTL UART module 7 receive. U7Tx 8 O TTL UART module 7 transmit. System Control & Clocks UART a Pin Number Description Non-maskable interrupt. a. The TTL designation indicates the pin has TTL-compatible voltage levels. 20.4 GPIO Pins and Alternate Functions Table 20-5. GPIO Pins and Alternate Functions a Digital Function (GPIOPCTL PMCx Bit Field Encoding) IO Pin Analog Function 1 2 3 4 5 6 7 8 9 14 15 PA0 17 - U0Rx - - - - - - - - - - PA1 18 - U0Tx - - - - - - - - - - PA2 19 - - SSI0Clk - - - - - - - - - PA3 20 - - SSI0Fss - - - - - - - - - PA4 21 - - SSI0Rx - - - - - - - - - PA5 22 - - SSI0Tx - - - - - - - - - PA6 23 - - - I2C1SCL - - - - - - - - PA7 24 - - - I2C1SDA - - - - - - - - June 12, 2014 1091 Texas Instruments-Production Data Signal Tables Table 20-5. GPIO Pins and Alternate Functions (continued) a Digital Function (GPIOPCTL PMCx Bit Field Encoding) IO Pin Analog Function 1 2 3 4 5 6 7 8 9 14 15 PB0 45 - U1Rx - - - - - T2CCP0 - - - - PB1 46 - U1Tx - - - - - T2CCP1 - - - - PB2 47 - - - I2C0SCL - - - T3CCP0 - - - - PB3 48 - - - I2C0SDA - - - T3CCP1 - - - - PB4 58 AIN10 - SSI2Clk - - - - T1CCP0 CAN0Rx - - - PB5 57 AIN11 - SSI2Fss - - - - T1CCP1 CAN0Tx - - - PB6 1 - - SSI2Rx - - - - T0CCP0 - - - - PB7 4 - - SSI2Tx - - - - T0CCP1 - - - - PC0 52 - TCK SWCLK - - - - - T4CCP0 - - - - PC1 51 - TMS SWDIO - - - - - T4CCP1 - - - - PC2 50 - TDI - - - - - T5CCP0 - - - - PC3 49 - TDO SWO - - - - - T5CCP1 - - - - PC4 16 C1- U4Rx U1Rx - - - - WT0CCP0 U1RTS - - - PC5 15 C1+ U4Tx U1Tx - - - - WT0CCP1 U1CTS - - - PC6 14 C0+ U3Rx - - - - - WT1CCP0 - - - - PC7 13 C0- U3Tx - - - - - WT1CCP1 - - - - PD0 61 AIN7 SSI3Clk SSI1Clk I2C3SCL - - - WT2CCP0 - - - - PD1 62 AIN6 SSI3Fss SSI1Fss I2C3SDA - - - WT2CCP1 - - - - PD2 63 AIN5 SSI3Rx SSI1Rx - - - - WT3CCP0 - - - - PD3 64 AIN4 SSI3Tx SSI1Tx - - - - WT3CCP1 - - - - PD4 43 - U6Rx - - - - - WT4CCP0 - - - - PD5 44 - U6Tx - - - - - WT4CCP1 - - - - PD6 53 - U2Rx - - - - - WT5CCP0 - - - - PD7 10 - U2Tx - - - - - WT5CCP1 NMI - - - PE0 9 AIN3 U7Rx - - - - - - - - - - PE1 8 AIN2 U7Tx - - - - - - - - - - PE2 7 AIN1 - - - - - - - - - - - PE3 6 AIN0 - - - - - - - - - - - PE4 59 AIN9 U5Rx - I2C2SCL - - - - CAN0Rx - - - PE5 60 AIN8 U5Tx - I2C2SDA - - - - CAN0Tx - - - PF0 28 - U1RTS SSI1Rx CAN0Rx - - - T0CCP0 NMI C0o - - PF1 29 - U1CTS SSI1Tx - - - - T0CCP1 - C1o TRD1 - PF2 30 - - SSI1Clk - - - - T1CCP0 - - TRD0 - PF3 31 - - SSI1Fss CAN0Tx - - - T1CCP1 - - TRCLK - PF4 5 - - - - - T2CCP0 - - - - - - a. The digital signals that are shaded gray are the power-on default values for the corresponding GPIO pin. Encodings 10-13 are not used on this device. 1092 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 20.5 Possible Pin Assignments for Alternate Functions Table 20-6. Possible Pin Assignments for Alternate Functions # of Possible Assignments one Alternate Function GPIO Function AIN0 PE3 AIN1 PE2 AIN10 PB4 AIN11 PB5 AIN2 PE1 AIN3 PE0 AIN4 PD3 AIN5 PD2 AIN6 PD1 AIN7 PD0 AIN8 PE5 AIN9 PE4 C0+ PC6 C0- PC7 C0o PF0 C1+ PC5 C1- PC4 C1o PF1 I2C0SCL PB2 I2C0SDA PB3 I2C1SCL PA6 I2C1SDA PA7 I2C2SCL PE4 I2C2SDA PE5 I2C3SCL PD0 I2C3SDA PD1 SSI0Clk PA2 SSI0Fss PA3 SSI0Rx PA4 SSI0Tx PA5 SSI2Clk PB4 SSI2Fss PB5 SSI2Rx PB6 SSI2Tx PB7 SSI3Clk PD0 SSI3Fss PD1 SSI3Rx PD2 SSI3Tx PD3 SWCLK PC0 June 12, 2014 1093 Texas Instruments-Production Data Signal Tables Table 20-6. Possible Pin Assignments for Alternate Functions (continued) # of Possible Assignments Alternate Function GPIO Function SWDIO PC1 SWO PC3 T2CCP1 PB1 T3CCP0 PB2 T3CCP1 PB3 T4CCP0 PC0 T4CCP1 PC1 T5CCP0 PC2 T5CCP1 PC3 TCK PC0 TDI PC2 TDO PC3 TMS PC1 TRCLK PF3 TRD0 PF2 TRD1 PF1 U0Rx PA0 U0Tx PA1 U2Rx PD6 U2Tx PD7 U3Rx PC6 U3Tx PC7 U4Rx PC4 U4Tx PC5 U5Rx PE4 U5Tx PE5 U6Rx PD4 U6Tx PD5 U7Rx PE0 U7Tx PE1 WT0CCP0 PC4 WT0CCP1 PC5 WT1CCP0 PC6 WT1CCP1 PC7 WT2CCP0 PD0 WT2CCP1 PD1 WT3CCP0 PD2 WT3CCP1 PD3 WT4CCP0 PD4 WT4CCP1 PD5 WT5CCP0 PD6 1094 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 20-6. Possible Pin Assignments for Alternate Functions (continued) # of Possible Assignments Alternate Function GPIO Function WT5CCP1 PD7 NMI PD7 PF0 SSI1Clk PD0 PF2 SSI1Fss PD1 PF3 SSI1Rx PD2 PF0 SSI1Tx PD3 PF1 T0CCP0 PB6 PF0 T0CCP1 PB7 PF1 T1CCP0 PB4 PF2 T1CCP1 PB5 PF3 two T2CCP0 PB0 PF4 U1CTS PC5 PF1 U1RTS PC4 PF0 U1Rx PB0 PC4 U1Tx PB1 PC5 CAN0Rx PB4 PE4 PF0 CAN0Tx PB5 PE5 PF3 three 20.6 Connections for Unused Signals Table 20-7 on page 1095 shows how to handle signals for functions that are not used in a particular system implementation for devices that are in a 64-pin LQFP package. Two options are shown in the table: an acceptable practice and a preferred practice for reduced power consumption and improved EMC characteristics. If a module is not used in a system, and its inputs are grounded, it is important that the clock to the module is never enabled by setting the corresponding bit in the RCGCx register. Table 20-7. Connections for Unused Signals (64-Pin LQFP) Function GPIO Signal Name Pin Number Acceptable Practice Preferred Practice All unused GPIOs - NC GND HIB 33 NC NC VBAT 37 NC VDD WAKE 32 NC GND XOSC0 34 NC GND XOSC1 36 NC NC GNDX 35 GND GND NC See NC pin numbers in Table 20-3 on page 1082 NC NC OSC0 40 NC GND OSC1 41 NC NC RST 38 VDD Pull up as shown in Figure 5-1 on page 205 Hibernate No Connects System Control June 12, 2014 1095 Texas Instruments-Production Data Electrical Characteristics 21 Electrical Characteristics 21.1 Maximum Ratings The maximum ratings are the limits to which the device can be subjected without permanently damaging the device. Device reliability may be adversely affected by exposure to absolute-maximum ratings for extended periods. Note: The device is not guaranteed to operate properly at the maximum ratings. Table 21-1. Absolute Maximum Ratings Value a Parameter Parameter Name VDD VDD supply voltage b Unit Min Max 0 4 V VDDA VDDA supply voltage 0 4 V VBAT VBAT battery supply voltage 0 4 V VBAT battery supply voltage ramp time 0 0.7 V/µs Input voltage on GPIOs, regardless of whether the cde microcontroller is powered -0.3 5.5 V Input voltage for PD4, PD5, PB0 and PB1 when configured as GPIO -0.3 VDD + 0.3 V - 25 mA -65 150 °C - 150 °C VBATRMP VIN_GPIO IGPIOMAX TS TJMAX Maximum current per output pin Unpowered storage temperature range Maximum junction temperature a. Voltages are measured with respect to GND. b. To ensure proper operation, VDDA must be powered before VDD if sourced from different supplies, or connected to the same supply as VDD. Note that the minimum operating voltage for VDD differs from the minimum operating voltage for VDDA. This change should be accounted for in the system design if both are sourced from the same supply. There is not a restriction on order for powering off. c. Applies to static and dynamic signals including overshoot. d. Refer to Figure 21-16 on page 1124 for a representation of the ESD protection on GPIOs. e. For additional details, see the note on GPIO pad tolerance in “GPIO Module Characteristics” on page 1123. Important: This device contains circuitry to protect the I/Os against damage due to high-static voltages; however, it is advised that normal precautions be taken to avoid application of any voltage higher than maximum-rated voltages to this high-impedance circuit. Reliability of operation is enhanced if unused inputs are connected to an appropriate logic voltage level (see “Connections for Unused Signals” on page 1095). Table 21-2. ESD Absolute Maximum Ratings Parameter Component-Level ESD a Stress Voltage Min Nom VESDHBM b Max Unit - VESDCDM c - - 2.0 kV - 500 V a. Electrostatic discharge (ESD) to measure device sensitivity/immunity to damage caused by electrostatic discharges in device. b. Level listed is passing level per ANSI/ESDA/JEDEC JS-001. JEDEC document JEP155 states that 500V HBM allows safe manufacturing with a standard ESD control process. c. Level listed is the passing level per EIA-JEDEC JESD22-C101E. JEDEC document JEP157 states that 250V CDM allows safe manufacturing with a standard ESD control process. 1096 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.2 Operating Characteristics Table 21-3. Temperature Characteristics Characteristic Symbol Value Ambient operating temperature range TA Unit -40 to +85 °C Case operating temperature range TC -40 to +93 °C Junction operating temperature range TJ -40 to +96 °C a Table 21-4. Thermal Characteristics Characteristic Symbol Value b Thermal resistance (junction to ambient) ΘJA b Unit 54.8 °C/W Thermal resistance (junction to board) ΘJB 27.5 °C/W Thermal resistance (junction to case) b ΘJC 15.8 °C/W Thermal metric (junction to top of package) ΨJT 0.7 °C/W Thermal metric (junction to board) ΨJB 27.1 °C/W Junction temperature formula TJ TC + (P • ΨJT) °C c TPCB + (P • ΨJB) d TA + (P • ΘJA) ef TB + (P • ΘJB) a. For more details about thermal metrics and definitions, see the Semiconductor and IC Package Thermal Metrics Application Report (literature number SPRA953). b. Junction to ambient thermal resistance (ΘJA), junction to board thermal resistance (ΘJB), and junction to case thermal resistance (ΘJC) numbers are determined by a package simulator. c. TPCB is the temperature of the board acquired by following the steps listed in the EAI/JESD 51-8 standard summarized in the Semiconductor and IC Package Thermal Metrics Application Report (literature number SPRA953). d. Because ΘJA is highly variable and based on factors such as board design, chip/pad size, altitude, and external ambient temperature, it is recommended that equations containing ΨJT and ΨJB be used for best results. e. TB is temperature of the board. f. ΘJB is not a pure reflection of the internal resistance of the package because it includes the resistance of the testing board and environment. It is recommended that equations containing ΨJT and ΨJB be used for best results. June 12, 2014 1097 Texas Instruments-Production Data Electrical Characteristics 21.3 Recommended Operating Conditions For special high-current applications, the GPIO output buffers may be used with the following restrictions. With the GPIO pins configured as 8-mA output drivers, a total of four GPIO outputs may be used to sink current loads up to 18 mA each. At 18-mA sink current loading, the VOL value is specified as 1.2 V. The high-current GPIO package pins must be selected such that there are only a maximum of two per side of the physical package with the total number of high-current GPIO outputs not exceeding four for the entire package. Table 21-5. Recommended DC Operating Conditions Parameter Parameter Name Min Nom Max Unit VDD VDD supply voltage 3.15 3.3 3.63 V VDDA VDDA supply voltage 2.97 3.3 3.63 V VDDC VDDC supply voltage 1.08 1.2 1.32 V VDDC supply voltage, Deep-sleep mode 1.08 - 1.32 V ab VDDCDS a. These values are valid when LDO is in operation. b. There are peripheral timing restrictions for SSI and LPC in Deep-sleep mode. Please refer to those peripheral characteristic sections for more information. Table 21-6. Recommended GPIO Pad Operating Conditions Parameter Parameter Name Min Nom Max Unit VIH GPIO high-level input voltage 0.65 * VDD - 5.5 V VIL GPIO low-level input voltage 0 - 0.35 * VDD V - V VHYS GPIO input hysteresis 0.2 - VOH GPIO high-level output voltage 2.4 - - V VOL GPIO low-level output voltage - - 0.4 V 2-mA Drive 2.0 - - mA 4-mA Drive 4.0 - - mA 8-mA Drive 8.0 - - mA 2-mA Drive 2.0 - - mA 4-mA Drive 4.0 - - mA 8-mA Drive 8.0 - - mA 8-mA Drive, VOL=1.2 V 18.0 - - mA a High-level source current, VOH=2.4 V IOH a Low-level sink current, VOL=0.4 V IOL a. IO specifications reflect the maximum current where the corresponding output voltage meets the VOH/VOL thresholds. IO current can exceed these limits (subject to absolute maximum ratings). a Table 21-7. GPIO Current Restrictions Parameter IMAXL Parameter Name b Cumulative maximum GPIO current per side, left b Min Nom Max Unit - - 30 mA IMAXB Cumulative maximum GPIO current per side, bottom - - 35 mA IMAXR b Cumulative maximum GPIO current per side, right - - 40 mA IMAXT Cumulative maximum GPIO current per side, top b - - 40 mA a. Based on design simulations, not tested in production. b. Sum of sink and source current for GPIOs as shown in Table 21-8 on page 1099. 1098 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 21-8. GPIO Package Side Assignments Side GPIOs Left PB[6-7], PC[4-7], PD7, PE[0-3], PF4 Bottom PA[0-7], PF[0-3] Right PB[0-3], PD[4-5] Top PB[4-5], PC[0-3], PD[0-3,6], PE[4-5] June 12, 2014 1099 Texas Instruments-Production Data Electrical Characteristics 21.4 Load Conditions Unless otherwise specified, the following conditions are true for all timing measurements. Figure 21-1. Load Conditions CL = 50 pF pin GND 1100 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.5 JTAG and Boundary Scan Table 21-9. JTAG Characteristics Parameter No. Parameter Parameter Name J1 FTCK TCK operational clock frequency J2 TTCK TCK operational clock period a Min Nom Max Unit 0 - 10 MHz 100 - - ns J3 TTCK_LOW TCK clock Low time - tTCK/2 - ns J4 TTCK_HIGH TCK clock High time - tTCK/2 - ns J5 TTCK_R TCK rise time 0 - 10 ns J6 TTCK_F TCK fall time 0 - 10 ns J7 TTMS_SU TMS setup time to TCK rise 8 - - ns J8 TTMS_HLD TMS hold time from TCK rise 4 - - ns J9 TTDI_SU TDI setup time to TCK rise 18 - - ns J10 TTDI_HLD TDI hold time from TCK rise 4 TCK fall to Data Valid from High-Z, 2-mA drive TCK fall to Data Valid from High-Z, 4-mA drive J11 TTDO_ZDV TCK fall to Data Valid from High-Z, 8-mA drive - TTDO_DV TTDO_DVZ ns ns 9 26 ns 8 26 ns 10 29 ns TCK fall to Data Valid from Data Valid, 2-mA drive 14 20 ns 10 26 ns 8 21 ns TCK fall to Data Valid from Data Valid, 8-mA drive with slew rate control 10 26 ns TCK fall to High-Z from Data Valid, 2-mA drive 7 16 ns 7 16 ns 7 16 ns 8 19 ns TCK fall to Data Valid from Data Valid, 8-mA drive - TCK fall to High-Z from Data Valid, 4-mA drive J13 35 TCK fall to Data Valid from High-Z, 8-mA drive with slew rate control TCK fall to Data Valid from Data Valid, 4-mA drive J12 13 TCK fall to High-Z from Data Valid, 8-mA drive - TCK fall to High-Z from Data Valid, 8-mA drive with slew rate control a. A ratio of at least 8:1 must be kept between the system clock and TCK. Figure 21-2. JTAG Test Clock Input Timing J2 J3 J4 TCK J6 J5 June 12, 2014 1101 Texas Instruments-Production Data Electrical Characteristics Figure 21-3. JTAG Test Access Port (TAP) Timing TCK J7 TMS TDI J8 J8 TMS Input Valid TMS Input Valid J9 J9 J10 TDI Input Valid J11 TDO J7 J10 TDI Input Valid J12 TDO Output Valid 1102 J13 TDO Output Valid June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.6 Power and Brown-Out Table 21-10. Power-On and Brown-Out Levels Parameter No. Parameter Parameter Name P1 TVDDA_RISE P2 TVDD_RISE P3 a TVDDC_RISE P4 VPOR P5 VVDDA_POK b Min Nom Max Unit Analog Supply Voltage (VDDA) Rise Time - - ∞ µs I/O Supply Voltage (VDD) Rise Time - - ∞ µs Core Supply Voltage (VDDC) Rise Time 10.00 - 150.00 µs Power-On Reset Threshold 2.00 2.30 2.60 V VDDA Power-OK Threshold (Rising Edge) 2.70 2.85 3.00 V VDDA Power-OK Threshold (Falling Edge) 2.71 2.80 2.89 V VDD Power-OK Threshold (Rising Edge) 2.85 3.00 3.15 V P6 VVDD_POK VDD Power-OK Threshold (Falling Edge) 2.70 2.78 2.87 V P7 VVDD_BOR0 Brown-Out 0 Reset Threshold 2.93 3.02 3.11 V P8 VVDD_BOR1 Brown-Out 1 Reset Threshold 2.83 2.92 3.01 V P9 VVDDC_POK VDDC Power-OK Threshold (Rising Edge) 0.80 0.95 1.10 V VDDC Power-OK Threshold (Falling Edge) 0.71 0.80 0.89 V a. The MIN and MAX values are guaranteed by design assuming the external filter capacitor load is within the range of CLDO. Please refer to “On-Chip Low Drop-Out (LDO) Regulator” on page 1111 for the CLDO value. b. Digital logic, Flash memory, and SRAM are all designed to operate at VDD voltages below 2.70 V. The internal POK reset protects the device from unpredictable operation on power down. 21.6.1 VDDA Levels The VDDA supply has two monitors: ■ Power-On Reset (POR) ■ Power-OK (POK) The POR monitor is used to keep the analog circuitry in reset until the VDDA supply has reached the correct range for the analog circuitry to begin operating. The POK monitor is used to keep the digital circuitry in reset until the VDDA power supply is at an acceptable operational level. The digital Power-On Reset (Digital POR) is only released when the Power-On Reset has deasserted and all of the Power-OK monitors for each of the supplies indicate that power levels are in operational ranges. Once the VDDA POK monitor has released the digital Power-On Reset on the initial power-up, voltage drops on the VDDA supply will only be reflected in the following bits. The digital Power-On Reset will not be re-asserted. ■ VDDARIS bit in the Raw Interrupt Status (RIS) register (see page 232). ■ VDDAMIS bit in the Masked Interrupt Status and Clear (MISC) register (see page 236). This bit is set only if the VDDAIM bit in the Interrupt Mask Control (IMC) register has been set. Figure 21-4 on page 1104 shows the relationship between VDDA, POR, POK, and an interrupt event. June 12, 2014 1103 Texas Instruments-Production Data Electrical Characteristics Figure 21-4. Power Assertions versus VDDA Levels P1 VDDAMIN 21.6.2 POR 1 POK 1 INT VDDA P5RISE P4 1 P5FALL P4 0 0 0 VDD Levels The VDD supply has three monitors: ■ Power-OK (POK) ■ Brown-Out Reset0 (BOR0) ■ Brown-Out Reset1 (BOR1) The POK monitor is used to keep the digital circuitry in reset until the VDD power supply is at an acceptable operational level. The digital Power-On Reset (Digital POR) is only released when the Power-On Reset has deasserted and all of the Power-OK monitors for each of the supplies indicate that power levels are in operational ranges. The BOR0 and the BOR1 monitors are used to generate a reset to the device or assert an interrupt if the VDD supply drops below its operational range. The BOR1 monitor's threshold is in between the BOR0 and POK thresholds. If either a BOR0 event or a BOR1 event occurs, the following bits are affected: ■ BOR0RIS or BOR1RIS bits in the Raw Interrupt Status (RIS) register (see page 232). ■ BOR0MIS or BOR1MIS bits in the Masked Interrupt Status and Clear (MISC) register (see page 236). These bits are set only if the respective BOR0IM or BOR1IM bits in the Interrupt Mask Control (IMC) register have been set. ■ BOR bit in the Reset Cause (RESC) register (see page 239). This bit is set only if either of the BOR0 or BOR1 events have been configured to initiate a reset. In addition, the following bits control both the BOR0 and BOR1 events: ■ BOR0IM or BOR1IM bits in the Interrupt Mask Control (IMC) register (see page 234). 1104 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller ■ BOR0 or BOR1 bits in the Power-On and Brown-Out Reset Control (PBORCTL) register (see page 231). Figure 21-5 on page 1105 shows the relationship between: ■ VDD, POK, and a BOR0 event ■ VDD, POK, and a BOR1 event Figure 21-5. Power and Brown-Out Assertions versus VDD Levels P2 P6RISE P7 BOR1 BOR0 POK VDD VDDMIN 21.6.3 P8 P6FALL 1 0 1 0 1 0 VDDC Levels The VDDC supply has one monitor: the Power-OK (POK). The POK monitor is used to keep the digital circuitry in reset until the VDDC power supply is at an acceptable operational level. The digital Power-On Reset (Digital POR) is only released when the Power-On Reset has deasserted and all of the Power-OK monitors for each of the supplies indicate that power levels are in operational ranges. Figure 21-6 on page 1106 shows the relationship between POK and VDDC. June 12, 2014 1105 Texas Instruments-Production Data Electrical Characteristics Figure 21-6. POK assertion vs VDDC POK VDDC P3 21.6.4 VDDCMIN P9RISE P9FALL 1 0 VDD Glitches Figure 21-7 on page 1106 shows the response of the BOR0, BOR1, and the POR circuit to glitches on the VDD supply. Figure 21-7. POR-BOR0-BOR1 VDD Glitch Response 21.6.5 VDD Droop Response Figure 21-8 on page 1107 shows the response of the BOR0, BOR1, and the POR monitors to a drop on the VDD supply. 1106 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 21-8. POR-BOR0-BOR1 VDD Droop Response June 12, 2014 1107 Texas Instruments-Production Data Electrical Characteristics 21.7 Reset Table 21-11. Reset Characteristics Parameter No. Parameter R1 TDPORDLY R2 TIRTOUT R3 TBOR0DLY Parameter Name a Digital POR to Internal Reset assertion delay Standard Internal Reset time Internal Reset time with recovery code repair b (program or erase) Min Nom Max Unit 0.80 - 5.35 µs - 9 11.5 ms c - - 6400 ms a 0.25 - 1.95 µs a BOR0 to Internal Reset assertion delay R3 TBOR1DLY BOR1 to Internal Reset assertion delay 0.75 - 5.95 µs R4 TRSTMIN Minimum RST pulse width - 250 - ns R5 TIRHWDLY RST to Internal Reset assertion delay - 250 - ns R6 TIRSWR Internal reset timeout after software-initiated system reset - 2.07 - µs R7 TIRWDR Internal reset timeout after Watchdog reset - 2.10 - µs R8 TIRMFR Internal reset timeout after MOSC failure reset - 1.92 - µs a. Timing values are dependent on the VDD power-down ramp rate. b. This parameter applies only in situations where a power-loss or brown-out event occurs during an EEPROM program or erase operation, and EEPROM needs to be repaired (which is a rare case). For all other sequences, there is no impact to normal Power-On Reset (POR) timing. This delay is in addition to other POR delays. c. This value represents the maximum internal reset time when the EEPROM reaches its endurance limit. Figure 21-9. Digital Power-On Reset Timing Digital POR R1 R2 Reset (Internal) Note: The digital Power-On Reset is only released when the analog Power-On Reset has deasserted and all of the Power-OK monitors for each of the supplies indicate that power levels are in operational ranges. 1108 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 21-10. Brown-Out Reset Timing BOR R3 R2 Reset (Internal) Figure 21-11. External Reset Timing (RST) R4 RST (Package Pin) R5 R2 Reset (Internal) Figure 21-12. Software Reset Timing Software Reset R6 Reset (Internal) Figure 21-13. Watchdog Reset Timing Watchdog Reset R7 Reset (Internal) June 12, 2014 1109 Texas Instruments-Production Data Electrical Characteristics Figure 21-14. MOSC Failure Reset Timing MOSC Fail Reset R8 Reset (Internal) 1110 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.8 On-Chip Low Drop-Out (LDO) Regulator Table 21-12. LDO Regulator Characteristics Parameter Parameter Name Min Nom Max Unit CLDO External filter capacitor size for internal power a supply 2.5 - 4.0 µF ESR Filter capacitor equivalent series resistance 10 - 100 mΩ ESL Filter capacitor equivalent series inductance VLDO LDO output voltage IINRUSH Inrush current - - 0.5 nH 1.08 1.2 1.32 V 50 - 250 mA a. The capacitor should be connected as close as possible to pin 56. June 12, 2014 1111 Texas Instruments-Production Data Electrical Characteristics 21.9 Clocks The following sections provide specifications on the various clock sources and mode. 21.9.1 PLL Specifications The following tables provide specifications for using the PLL. Table 21-13. Phase Locked Loop (PLL) Characteristics Parameter FREF_XTAL Parameter Name External clock PLL frequency Max Unit - 25 MHz 5 - 25 MHz - 400 - 5 a referencea FPLL Nom a Crystal reference FREF_EXT TREADY Min b MHz c reference clocks c reference clocks PLL lock time, enabling the PLL - - 512 * (N+1) PLL lock time, changing the XTAL field in the RCC/RCC2 register or changing the OSCSRC between MOSC and PIOSC - - 128 * (N+1) d d a. If the PLL is not used, the minimum input frequency can be 4 MHz. b. PLL frequency is automatically calculated by the hardware based on the XTAL field of the RCC register. The PLL frequency that is set by the hardware can be calculated using the values in the PLLFREQ0 and PLLFREQ1 registers. c. N is the value in the N field in the PLLFREQ1 register. d. A reference clock is the clock period of the crystal being used, which can be MOSC or PIOSC. For example, a 16-MHz crystal connected to MOSC yields a reference clock of 62.5 ns. Table 21-14 on page 1112 shows the actual frequency of the PLL based on the crystal frequency used (defined by the XTAL field in the RCC register). Table 21-14. Actual PLL Frequency XTAL Crystal Frequency (MHz) MINT MFRAC Q N PLL Multiplier PLL Frequency (MHz) Error 0x09 5.0 0x50 0x0 0x0 0x0 80 400 - 0x0A 5.12 0x9C 0x100 0x0 0x1 156.25 400 - 0x0B 6.0 0xC8 0x0 0x0 0x2 200 400 - 0x0C 6.144 0xC3 0x140 0x0 0x2 195.3125 400 - 0x0D 7.3728 0xA2 0x30A 0x0 0x2 162.7598 399.9984 0.0004% 0x0E 8.0 0x32 0x0 0x0 0x0 50 400 - 0x0F 8.192 0xC3 0x140 0x0 0x3 195.3125 400 - 0x10 10.0 0x50 0x0 0x0 0x1 80 400 - 0x11 12.0 0xC8 0x0 0x0 0x5 200 400 - 0x12 12.288 0xC3 0x140 0x0 0x5 195.3125 400 - 0x13 13.56 0xB0 0x3F6 0x0 0x5 176.9902 399.9979 0.0005% 0x14 14.318 0xC3 0x238 0x0 0x6 195.5547 399.9982 0.0005% 0x15 16.0 0x32 0x0 0x0 0x1 50 400 - 0x16 16.384 0xC3 0x140 0x0 0x7 195.3125 400 - 0x17 18 0xC8 0x0 0x0 0x8 200 400 - 0x18 20 0x50 0x0 0x0 0x3 80 400 - 0x19 24 0x32 0x0 0x0 0x2 50 400 - 1112 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 21-14. Actual PLL Frequency (continued) 21.9.2 XTAL Crystal Frequency (MHz) MINT MFRAC Q N PLL Multiplier PLL Frequency (MHz) Error 0x1A 25 0x50 0x0 0x0 0x4 80 400 - PIOSC Specifications Table 21-15. PIOSC Clock Characteristics Parameter FPIOSC Parameter Name Min Nom Max Unit Factory calibration: - - ±3% - - - ±1% a - - - 1 µs Internal 16-MHz precision oscillator frequency variance across the specified voltage and temperature range when factory calibration is used Recalibration: Internal 16-MHz precision oscillator frequency variance when 7-bit recalibration is used TSTART b PIOSC startup time a. ±1% is only guaranteed at the specific voltage/temperature condition where the recalibration occurs. b. PIOSC startup time is part of reset and is included in the internal reset timeout value (TIRTOUT) given in Table 21-11 on page 1108. Note that the TSTART value is based on simulation. 21.9.3 Low-Frequency Internal Oscillator (LFIOSC) Specifications Table 21-16. Low-Frequency internal Oscillator Characteristics Parameter FLFIOSC 21.9.4 Parameter Name Low-frequency internal oscillator (LFIOSC) frequency Min Nom Max Unit 10 33 90 KHz Hibernation Clock Source Specifications Table 21-17. Hibernation Oscillator Input Characteristics Parameter Parameter Name FHIBLFIOSC Hibernation low frequency internal oscillator (HIB LFIOSC) frequency C1, C2 CINSE CPKG CPCB CSHUNT Min Nom Max Unit 10 33 90 KHz External load capacitance on XOSC0, XOSC1 pins 12 - 24 pF Input capacitance of XOSC0 in single-ended mode - - 2 pF - 0.5 - pF a a Device package stray shunt capacitance a PCB stray shunt capacitance - 0.5 - pF - - 4 pF b - - 50 kΩ b Crystal effective series resistance, OSCDRV = 1 - - 75 kΩ Oscillator output drive level - - 0.25 µW - 600 1500 ms CMOS input high level, when using an external oscillator with Supply > 3.3 V 2.64 - - V CMOS input high level, when using an external oscillator with 1.8 V ≤ Supply ≤ 3.3 V 0.8 * Supply - - V a Total shunt capacitance Crystal effective series resistance, OSCDRV = 0 ESR DL TSTART e VIH c Oscillator startup time, when using a crystal June 12, 2014 d 1113 Texas Instruments-Production Data Electrical Characteristics Table 21-17. Hibernation Oscillator Input Characteristics (continued) Parameter e VIL e VHYS Parameter Name Min Nom Max Unit CMOS input low level, when using an external oscillator with 1.8 V ≤ Supply ≤ 3.63 V - - 0.2 * Supply V CMOS input buffer hysteresis, when using an external oscillator with 1.8 V ≤ Supply ≤ 3.63 V 360 960 1390 mV 30 - 70 % DCHIBOSC_EXT External clock reference duty cycle a. See information below table. b. Crystal ESR specified by crystal manufacturer. c. Oscillator startup time is specified from the time the oscillator is enabled to when it reaches a stable point of oscillation such that the internal clock is valid. d. Only valid for recommended supply conditions. Measured with OSCDRV bit set (high drive strength enabled, 24 pF). e. Specification is relative to the larger of VDD or VBAT. The load capacitors added on the board, C1 and C2, should be chosen such that the following equation is satisfied (see Table 21-17 on page 1113 for typical values). ■ CL = load capacitance specified by crystal manufacturer ■ CL = (C1*C2)/(C1+C2) + CPKG + CPCB ■ CSHUNT = CPKG + CPCB + C0 (total shunt capacitance seen across XOSC0, XOSC1) ■ CPKG, CPCB as measured across the XOSC0, XOSC1 pins excluding the crystal ■ Clear the OSCDRV bit in the Hibernation Control (HIBCTL) register for C1,2 ≤ 18 pF; set the OSCDRV bit for C1,2 > 18 pF. ■ C0 = Shunt capacitance of crystal specified by the crystal manufacturer 21.9.5 Main Oscillator Specifications Table 21-18. Main Oscillator Input Characteristics Parameter Parameter Name Min FMOSC Parallel resonance frequency C1, C2 External load capacitance on OSC0, OSC1 pins CPKG CPCB CSHUNT b b Device package stray shunt capacitance b PCB stray shunt capacitance b Total shunt capacitance MHz pF 0.5 - pF - 0.5 - pF - - 4 pF - 300 Ω cd - - 200 Ω cd - - 130 Ω cd - - 120 Ω cd - - 100 Ω cd - - 50 Ω - OSCPWR - mW - - 18 ms 0.65 * VDD - VDD V Crystal effective series resistance, 12 MHz Crystal effective series resistance, 16 MHz Crystal effective series resistance, 25 MHz VIH 25 24 - Crystal effective series resistance, 8 MHz TSTART - 4 - Crystal effective series resistance, 6 MHz DL Unit 10 Nom cd Crystal effective series resistance, 4 MHz ESR Max a e Oscillator output drive level f Oscillator startup time, when using a crystal CMOS input high level, when using an external oscillator 1114 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 21-18. Main Oscillator Input Characteristics (continued) Parameter Parameter Name Min Nom Max VIL CMOS input low level, when using an external oscillator GND - 0.35 * VDD V VHYS CMOS input buffer hysteresis, when using an external oscillator 150 - - mV External clock reference duty cycle 45 - 55 % DCOSC_EXT Unit a. 5 MHz is the minimum when using the PLL. b. See information below table. c. Crystal ESR specified by crystal manufacturer. d. Crystal vendors can be contacted to confirm these specifications are met for a specific crystal part number if the vendors generic crystal datasheet show limits outside of these specifications. e. OSCPWR = (2 * pi * FP * CL * 2.5)2 * ESR / 2. An estimation of the typical power delivered to the crystal is based on the CL, FP and ESR parameters of the crystal in the circuit as calculated by the OSCPWR equation. Ensure that the value calculated for OSCPWR does not exceed the crystal's drive-level maximum. f. Oscillator startup time is specified from the time the oscillator is enabled to when it reaches a stable point of oscillation such that the internal clock is valid. The load capacitors added on the board, C1 and C2, should be chosen such that the following equation is satisfied (see Table 21-18 on page 1114 for typical values and Table 21-19 on page 1116 for detailed crystal parameter information). ■ CL = load capacitance specified by crystal manufacturer ■ CL = (C1*C2)/(C1+C2) + CSHUNT ■ CSHUNT = C0 + CPKG + CPCB (total shunt capacitance seen across OSC0, OSC1 crystal inputs) ■ CPKG, CPCB = the mutual caps as measured across the OSC0,OSC1 pins excluding the crystal. ■ C0 = Shunt capacitance of crystal specified by the crystal manufacturer Table 21-19 on page 1116 lists part numbers of crystals that have been simulated and confirmed to operate within the specifications in Table 21-18 on page 1114. Other crystals that have nearly identical crystal parameters can be expected to work as well. In the table below, the crystal parameters labeled C0, C1 and L1 are values that are obtained from the crystal manufacturer. These numbers are usually a result of testing a relevant batch of crystals on a network analyzer. The parameters labeled ESR, DL and CL are maximum numbers usually available in the data sheet for a crystal. The table also includes three columns of Recommended Component Values. These values apply to system board components. C1 and C2 are the values in pico Farads of the load capacitors that should be put on each leg of the crystal pins to ensure oscillation at the correct frequency. Rs is the value in kΩ of a resistor that is placed in series with the crystal between the OSC1 pin and the crystal pin. Rs dissipates some of the power so the Max Dl crystal parameter is not exceeded. Only use the recommended C1, C2, and Rs values with the associated crystal part. The values in the table were used in the simulation to ensure crystal startup and to determine the worst case drive level (WC Dl). The value in the WC Dl column should not be greater than the Max Dl Crystal parameter. The WC Dl value can be used to determine if a crystal with similar parameter values but a lower Max Dl value is acceptable. June 12, 2014 1115 Texas Instruments-Production Data Electrical Characteristics Crystal Spec (Tolerance / Stability) Max Values 12 0 132 ESR (Ω) Rs (kΩ) 12 C2 (pF) 8 C1 (pF) 500 CL (pf) 1.00 2.70 598.10 300 Max Dl (µW) 30/50 ppm L1 (mH) 4 C1 (fF) 8 x 4.5 C0 (pF) NX8045GB PKG Size Freq (MHz) NX8045GB- Typical Values Recommended Component Values (mm x mm) NDK Holder MFG MFG Part# Crystal Parameters WC Dl (μW) Table 21-19. Crystal Parameters 4.000M-STDCJL-5 FOX FQ1045A-4 2-SMD 10 x 4.5 4 30/30 ppm 1.18 4.05 396.00 150 500 10 14 14 0 103 NDK NX8045GB- NX8045GB 8 x 4.5 5 30/50 ppm 1.00 2.80 356.50 250 500 8 12 12 0 164 NX8045GB 8 x 4.5 6 30/50 ppm 1.30 4.10 173.20 250 500 8 12 12 0 214 5.000M-STDCSF-4 NDK NX8045GB6.000M-STDCSF-4 FOX FQ1045A-6 2-SMD 10 x 4.5 6 30/30 ppm 1.37 6.26 112.30 150 500 10 14 14 0 209 NDK NX8045GB- NX8045GB 8 x 4.5 8 30/50 ppm 1.00 2.80 139.30 200 500 8 12 12 0 277 4-SMD 7x5 8 30/30 ppm 1.95 6.69 59.10 80 500 10 14 14 0 217 8 50/30 ppm 1.82 4.90 85.70 80 500 16 24 24 0 298 7.2 x 5.2 12 10/20 ppm 2.37 8.85 50 500 10 12 12 2.0 a 124 NX3225GA 3.2 x 2.5 12 20/30 ppm 0.70 2.20 81.00 100 200 8 12 12 2.5 147 NX5032GA 5 x 3.2 12 30/50 ppm 0.93 3.12 56.40 120 500 8 12 12 0 362 4-SMD 5 x 3.2 12 30/30 ppm 1.16 4.16 42.30 500 10 14 14 0 8.000M-STDCSF-6 FOX FQ7050B-8 ECS ECS-80-16- HC49/US 12.5 x 4.85 28A-TR Abracon AABMM- ABMM 20.5 12.0000MHz10-D-1-X-T NDK NX3225GA12.000MHZSTD-CRG-2 NDK NX5032GA12.000MHZLN-CD-1 FOX FQ5032B-12 Abracon AABMM- ABMM 7.2 x 5.2 80 370 a 143 a 16 10/20 ppm 3.00 11.00 9.30 50 500 10 12 12 2.0 HC-49/UP 13.3 x 4.85 16 15/30 ppm 3.00 12.7 50 1000 10 12 12 2.0 139 NX3225GA 3.2 x 2.5 16 20/30 ppm 1.00 2.90 33.90 80 200 8 12 12 2 188 NX5032GA 16 30/50ppm 1.02 3.82 25.90 120 500 8 10 10 0 437 16.0000MHz10-D-1-X-T Ecliptek ECX-6595- 8.1 16.000M NDK NX3225GA16.000MHZSTD-CRG-2 NDK NX5032GA- 5 x 3.2 b 16.000MHZLN-CD-1 1116 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 21-19. Crystal Parameters (continued) WC Dl (μW) Max Values 289 ABMM 7.2 x 5.2 25 10/20 ppm 3.00 11.00 3.70 50 500 10 12 12 2.0 a 158 HC-49/UP 13.3 x 4.85 25 15/30 ppm 3.00 12.8 3.2 40 1000 10 12 12 1.5 a 159 NX3225GA 3.2 x 2.5 25 20/30 ppm 1.10 4.70 8.70 50 200 8 12 12 2 181 10 10 1.0 CL (pf) C1 (fF) Rs (kΩ) 0.5 C2 (pF) 12 C1 (pF) 12 Max Dl (µW) 9 ESR (Ω) 300 ECX-42 L1 (mH) 60 ECS-160-9-42- C0 (pF) 1.47 3.90 25.84 ECS PKG Size 10/10 ppm Holder 16 MFG Part# 4 x 2.5 MFG Freq (MHz) Typical Values Recommended Component Values (mm x mm) Crystal Spec (Tolerance / Stability) Crystal Parameters CKM-TR Abracon AABMM25.0000MHz10-D-1-X-T Ecliptek ECX-659325.000M NDK NX3225GA25.000MHZSTD-CRG-2 NX5032GA- NDK 25.000MHZ- a c 216 NX5032GA 5 x 3.2 25 30/50 ppm 1.3 5.1 7.1 70 500 8 12 12 0.75 269 HC3225/4 3.2 x 2.5 25 30/30 ppm 1.58 5.01 8.34 50 500 12 16 16 1 331 4-SMD 5 x 3.2 25 30/30 ppm 1.69 7.92 5.13 50 500 10 14 14 0.5 433 12 c 124 LD-CD-1 AURIS Q-25.000MHC3225/4F-30-30-E-12-TR FOX TXC FQ5032B-25 7A2570018 NX5032GA 5 x 3.2 25 20/25 ppm 2.0 6.7 6.1 30 350 10 12 2.0 a. RS values as low as 0 Ohms can be used. Using a lower RS value will result in the WC DL to increase towards the Max DL of the crystal. b. Although this ESR value is outside of the recommended crystal ESR maximum for this frequency, this crystal has been simulated to confirm proper operation and is valid for use with this device. c. RS values as low as 500 Ohms can be used. Using a lower RS value will result in the WC DL to increase towards the Max DL of the crystal. Table 21-20. Supported MOSC Crystal Frequencies Value Crystal Frequency (MHz) Not Using the PLL 0x00-0x5 0x06 Crystal Frequency (MHz) Using the PLL reserved 4 MHz reserved 0x07 4.096 MHz reserved 0x08 4.9152 MHz reserved 0x09 5 MHz 0x0A 5.12 MHz 0x0B 6 MHz 0x0C 6.144 MHz 0x0D 7.3728 MHz 0x0E 8 MHz 0x0F 8.192 MHz 0x10 10.0 MHz June 12, 2014 1117 Texas Instruments-Production Data Electrical Characteristics Table 21-20. Supported MOSC Crystal Frequencies (continued) Value 21.9.6 Crystal Frequency (MHz) Not Using the PLL Crystal Frequency (MHz) Using the PLL 0x11 12.0 MHz 0x12 12.288 MHz 0x13 13.56 MHz 0x14 14.31818 MHz 0x15 16.0 MHz (reset value) 0x16 16.384 MHz 0x17 18.0 MHz 0x18 20.0 MHz 0x19 24.0 MHz 0x1A 25.0 MHz System Clock Specification with ADC Operation Table 21-21. System Clock Characteristics with ADC Operation Parameter Fsysadc Parameter Name System clock frequency when the ADC a module is operating (when PLL is bypassed). Min Nom Max Unit 15.9952 16 16.0048 MHz a. Clock frequency (plus jitter) must be stable inside specified range. ADC can be clocked from the PLL, directly from an external clock source, or from the PIOSC, as long as frequency absolute precision is inside specified range. 1118 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.10 Sleep Modes a Table 21-22. Sleep Modes AC Characteristics Parameter No Parameter Min Nom Max Unit Time to wake from interrupt in sleep mode - - 2 system clocks Time to wake from interrupt in deep-sleep mode, using PIOSC for both Run mode and Deep-sleep bc mode - 1.25 - µs Time to wake from interrupt in deep-sleep mode, using PIOSC for Run mode and LFIOSC for bc Deep-sleep mode - 350 - µs TWAKE_PLL_DS Time to wake from interrupt in deep-sleep mode b when using the PLL - - TREADY ms TWAKE_S D1 TWAKE_DS D2 Parameter Name b a. Values in this table assume the LFIOSC is the clock source during sleep or deep-sleep mode. b. Specified from registering the interrupt to first instruction. c. If the main oscillator is used for run mode, add the main oscillator startup time, TSTART. ab Table 21-23. Time to Wake with Respect to Low-Power Modes Mode Sleep/Deep-Sleep Run Mode Mode FLASHPM SRAMPM Clock/Frequency Clock/Frequency 0x0 Sleep MOSC, PLL on 80MHz MOSC, PLL on 80MHz 0x2 Time to Wake Unit Min Max 0x0 0.28 0.30 µs 0x1 33.57 35.00 µs 0x3 33.75 35.05 µs 0x0 105.02 109.23 µs 0x1 137.85 143.93 µs 0x3 138.06 143.86 µs June 12, 2014 1119 Texas Instruments-Production Data Electrical Characteristics Table 21-23. Time to Wake with Respect to Low-Power Modes (continued) Mode Sleep/Deep-Sleep Run Mode Mode FLASHPM SRAMPM Clock/Frequency Clock/Frequency 0x0 MOSC, PLL on 80MHz PIOSC - 16MHz 0x2 0x0 PIOSC - 16MHz PIOSC - 16MHz 0x2 Deep-Sleep 0x0 PIOSC - 16MHz LFIOSC, PIOSC c off - 30kHz 0x2 0x0 MOSC, PLL on 80MHz LFIOSC, PIOSC c off - 30kHz 0x2 Time to Wake Unit Min Max 0x0 2.47 2.60 µs 0x1 35.31 36.35 µs 0x3 35.40 36.76 µs 0x0 107.05 111.54 µs 0x1 139.34 145.64 µs 0x3 140.41 145.53 µs 0x0 2.47 2.61 µs 0x1 35.25 36.65 µs 0x3 35.38 36.79 µs 0x0 107.43 111.52 µs 0x1 139.83 145.85 µs 0x3 139.35 145.54 µs 0x0 415.06 728.38 µs 0x1 436.60 740.88 µs 0x3 433.80 755.32 µs 0x0 503.73 812.82 µs 0x1 537.72 846.23 µs 0x3 536.10 839.25 µs 0x0 18.95 19.55 ms 0x1 18.94 19.54 ms 0x3 18.95 19.53 ms 0x0 18.95 19.54 ms 0x1 18.94 19.53 ms 0x3 18.95 19.54 ms a. Time from wake event to first instruction of code execution. b. If the LDO voltage is adjusted, it will take an extra 4 us to wake up from Sleep or Deep-sleep mode. c. PIOSC is turned off by setting the PIOSCPD bit in the DSLPCLKCFG register. 1120 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.11 Hibernation Module The Hibernation module requires special system implementation considerations because it is intended to power down all other sections of its host device, refer to “Hibernation Module” on page 458. Table 21-24. Hibernation Module Battery Characteristics Parameter VBAT b VBATRMP VLOWBAT Parameter Name Min Nominal Max Battery supply voltage 1.8 3.0 3.6 V 0 - 0.7 V/µs Low battery detect voltage, VBATSEL=0x0 1.8 1.9 2.0 V Low battery detect voltage, VBATSEL=0x1 2.0 2.1 2.2 V Low battery detect voltage, VBATSEL=0x2 2.2 2.3 2.4 V Low battery detect voltage, VBATSEL=0x3 2.4 2.5 2.6 V VBAT battery supply voltage ramp time a Unit a. To ensure proper functionality, any voltage input within the range of 3.6 V < VBAT ≤ 4 V must be connected through a diode. b. For recommended VBAT RC circuit values, refer to the diagrams located in“Hibernation Clock Source” on page 461. Table 21-25. Hibernation Module AC Characteristics Parameter No Parameter H1 TWAKE H2 TWAKE_TO_HIB H3 H4 Parameter Name Min Nom Max Unit 100 - - ns WAKE assert to HIB desassert (wake up time) - - 1 hibernation clock period TVDD_RAMP VDD ramp to 3.0 V - Depends on characteristics of power supply - μs TVDD_CODE VDD at 3.0 V to internal POR deassert; first instruction executes - - 500 μs WAKE assertion time Figure 21-15. Hibernation Module Timing H1 WAKE H2 HIB H3 VDD H4 POR June 12, 2014 1121 Texas Instruments-Production Data Electrical Characteristics 21.12 Flash Memory and EEPROM Table 21-26. Flash Memory Characteristics Parameter PECYC TRET TPROG64 TERASE TME Parameter Name a Number of program/erase cycles before failure Min Nom Max Unit 100,000 - - cycles Data retention, -40˚C to +85˚C 20 - - years Program time for double-word-aligned 64 bits of b data 30 50 300 µs Page erase time, 1. b. If programming fewer than 64 bits of data, the programming time is the same. For example, if only 32 bits of data need to be programmed, the other 32 bits are masked off. a Table 21-27. EEPROM Characteristics Parameter Parameter Name b EPECYC ETRET ETPROG ETREAD ETME Min Number of mass program/erase cycles of a single word before 500,000 c failure Data retention, -40˚C to +85˚C Nom Max Unit - - cycles 20 - - years Program time for 32 bits of data - space available - 110 600 μs Program time for 32 bits of data - requires a copy to the copy buffer, copy buffer has space and less than 10% of EEPROM endurance used - 30 - ms Program time for 32 bits of data - requires a copy to the copy buffer, copy buffer has space and greater than 90% of EEPROM endurance used - - 900 ms Program time for 32 bits of data - requires a copy to the copy buffer, copy buffer requires an erase and less than 10% of EEPROM endurance used - 60 - ms Program time for 32 bits of data - requires a copy to the copy buffer, copy buffer requires an erase and greater than 90% of EEPROM endurance used - - 1800 ms Read access time - 4 - system clocks Mass erase time, 0 -> 1. 1122 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.13 Input/Output Pin Characteristics 21.13.1 GPIO Module Characteristics Note: All GPIO signals are 5-V tolerant when configured as inputs except for PD4, PD5, PB0 and PB1, which are limited to 3.6 V. See “Signal Description” on page 614 for more information on GPIO configuration. Note: GPIO pads are tolerant to 5-V digital inputs without creating reliability issues, as long as the supply voltage, VDD, is present. There are limitations to how long a 5-V input can be present on any given I/O pad if VDD is not present. Not meeting these conditions will affect reliability of the device and affect the GPIO characteristics specifications. ■ If the voltage applied to a GPIO pad is in the high voltage range (5V +/- 10%) while VDD is not present, such condition should be allowed for a maximum of 10,000 hours at 27°C or 5,000 hours at 85°C, over the lifetime of the device. ■ If the voltage applied to a GPIO pad is in the normal voltage range (3.3V +/- 10%) while VDD is not present or if the voltage applied is in the high voltage range (5V +/- 10%) while VDD is present, there are no constraints on the lifetime of the device. a Table 21-28. GPIO Module Characteristics Parameter Parameter Name CGPIO Min Max Unit - 8 - pF RGPIOPU GPIO internal pull-up resistor 13 20 30 kΩ RGPIOPD GPIO internal pull-down resistor 13 20 35 kΩ GPIO input leakage current, 0 V ≤ VIN ≤ VDD GPIO b pins - - 1.0 µA GPIO input leakage current, 0 V < VIN ≤ VDD, GPIO pins configured as ADC or analog comparator inputs - - 2.0 µA 14.2 16.1 ns 11.9 15.5 ns 8.1 11.2 ns 9.5 11.8 ns 25.2 29.4 ns 13.3 16.8 ns 8.6 11.2 ns 11.3 12.9 ns ILKG+ GPIO Digital Input Capacitance Nom c GPIO rise time, 2-mA drive c TGPIOR GPIO rise time, 4-mA drive - c GPIO rise time, 8-mA drive c GPIO rise time, 8-mA drive with slew rate control d GPIO fall time, 2-mA drive d TGPIOF GPIO fall time, 4-mA drive - d GPIO fall time, 8-mA drive d GPIO fall time, 8-mA drive with slew rate control a. VDD must be within the range specified in Table 21-5 on page 1098. b. The leakage current is measured with VIN applied to the corresponding pin(s). The leakage of digital port pins is measured individually. The port pin is configured as an input and the pull-up/pull-down resistor is disabled. c. Time measured from 20% to 80% of VDD. d. Time measured from 80% to 20% of VDD. 21.13.2 Types of I/O Pins and ESD Protection With respect to ESD and leakage current, three types of I/O pins exist on the device: Power I/O pins, I/O pins with fail-safe ESD protection (GPIOs other than PD4 and PD5 , and XOSCn pins) and I/O pins with non-fail-safe ESD protection (any non-power, non-GPIO (other than PD4 and PD5) and June 12, 2014 1123 Texas Instruments-Production Data Electrical Characteristics non-XOSCn pins). This section covers I/O pins with fail-safe ESD protection and I/O pins with non-fail-safe ESD protection. Power I/O pin voltage and current limitations are specified in “Recommended Operating Conditions” on page 1098. 21.13.2.1 Fail-Safe Pins GPIOs other than PD4 and PD5, inputs for the Hibernate 32-kHz oscillator (XOSCn), and Hibernate inputs use ESD protection as shown in Figure 21-16 on page 1124. An unpowered device cannot be parasitically powered through any of these pins. This ESD protection prevents a direct path between these I/O pads and any power supply rails in the device. GPIO/XOSCn pad input voltages should be kept inside the maximum ratings specified in Table 21-1 on page 1096 to ensure current leakage and current injections are within acceptable range. Current leakages and current injection for these pins are specified in Table 21-28 on page 1123. Figure 21-16 on page 1124 shows a diagram of the ESD protection on fail-safe pins. Some GPIOs when configured as inputs require a strong pull-up resistor to maintain a threshold above the minimum value of VIH during power-on. See Table 21-30 on page 1125. Figure 21-16. ESD Protection on Fail-Safe Pins VDD I/O Pad ESD Clamp GND a Table 21-29. Pad Voltage/Current Characteristics for Fail-Safe Pins Parameter Parameter Name bb ILKG+ GPIO input leakage current, VDD< VIN ≤ 4.5 V bc GPIO input leakage current, 4.5 V < VIN ≤ 5.5 V bd ILKGIINJ+ IINJ- GPIO input leakage current, VIN < -0.3 V b GPIO input leakage current, -0.3 V ≤ VIN < 0 V fg DC injection current, VDD < VIN ≤ 5.5 V g DC injection current, VIN ≤ 0 V Min Nom Max Unit - - 700 µA - - 100 µA - - e - µA - - 10 µA - - ILKG+ µA - - 0.5 mA a. VIN must be within the range specified in Table 21-1 on page 1096. b. To protect internal circuitry from over-voltage, the GPIOs have an internal voltage clamp that limits internal swings to VDD without affecting swing at the I/O pad. This internal clamp starts turning on while VDD < VIN < 4.5 V and causes a somewhat larger (but bounded) current draw. To save power, static input voltages between VDD and 4.5 V should be avoided. c. Leakage current above maximum voltage (VIN = 5.5V) is not guaranteed, this condition is not allowed and can result in permanent damage to the device. d. Leakage outside the minimum range (-0.3V) is unbounded and must be limited to IINJ- using an external resistor. e. In this case, ILKG- is unbounded and must be limited to IINJ- using an external resistor. 1124 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller f. Current injection is internally bounded for GPIOs, and maximum current into the pin is given by ILKG+ for VDD < VIN < 5.5 V. g. If the I/O pad is not voltage limited, it should be current limited (to IINJ+ and IINJ-) if there is any possibility of the pad voltage exceeding the VIO limits (including transient behavior during supply ramp up, or at any time when the part is unpowered). Table 21-30. Fail-Safe GPIOs that Require an External Pull-up GPIO Pin Pull-Up Resistor Value Unit PB0 45 1k ≤ R ≤ 10k Ω PB1 46 1k ≤ R ≤ 10k Ω PE3 6 1k ≤ R ≤ 10k Ω 21.13.2.2 Non-Fail-Safe Pins The Main Oscillator (MOSC) crystal connection pins and GPIO pins PD4 and PD5 have ESD protection as shown in Figure 21-17 on page 1125. These pins have a potential path between the I/O pad and an internal power rail if either one of the ESD diodes is accidentally forward biased. The voltage and current of these pins should follow the specifications in Table 21-31 on page 1125 to prevent potential damage to the device. In addition to the specifications outlined in Table 21-31 on page 1125, it is recommended that the ADC external reference specifications in Table 21-32 on page 1127 be adhered to in order to prevent any gain error. Figure 21-17 on page 1125 shows a diagram of the ESD protection on non-fail-safe pins. Figure 21-17. ESD Protection on Non-Fail-Safe Pins VDD I/O Pad GND abcd Table 21-31. Non-Fail-Safe I/O Pad Voltage/Current Characteristics Parameter VIO ILKG+ Parameter Name Min Nom Max Unit -0.3 VDD VDD+0.3 V ef - - 10 µA ef - - 10 µA - - 2 mA - - -0.5 mA IO pad voltage limits Positive IO leakage for VIO Max ILKG- Negative IO leakage for VIO Min IINJ+ Max positive injection IINJ- Max negative injection if not voltage protected g g a. VIN must be within the range specified in Table 21-1 on page 1096. Leakage current outside of this maximum voltage is not guaranteed and can result in permanent damage of the device. b. VDD must be within the range specified in Table 21-5 on page 1098. June 12, 2014 1125 Texas Instruments-Production Data Electrical Characteristics c. To avoid potential damage to the part, either the voltage or current on the ESD-protected, non-Power, non-Hibernate/XOSC input/outputs should be limited externally as shown in this table. d. I/O pads should be protected if at any point the IO voltage has a possibility of going outside the limits shown in the table. If the part is unpowered, the IO pad Voltage or Current must be limited (as shown in this table) to avoid powering the part through the IO pad, causing potential irreversible damage. e. This value applies to an I/O pin that is voltage-protected within the Min and Max VIO ratings. Leakage outside the specified voltage range is unbounded and must be limited to IINJ- using an external resistor. f. MIN and MAX leakage current for the case when the I/O is voltage-protected to VIO Min or VIO Max. g. If an I/O pin is not voltage-limited, it should be current-limited (to IINJ+ and IINJ-) if there is any possibility of the pad voltage exceeding the VIO limits (including transient behavior during supply ramp up, or at any time when the part is unpowered). 1126 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.14 Analog-to-Digital Converter (ADC) ab Table 21-32. ADC Electrical Characteristics Parameter Parameter Name Min Nom Max Unit POWER SUPPLY REQUIREMENTS VDDA ADC supply voltage 2.97 3.3 3.63 V GNDA ADC ground voltage - 0 - V Voltage reference decoupling capacitance - 1.0 // 0.01 - μF Single-ended, full- scale analog input voltage, de internal reference 0 - VDDA V -VDDA - VDDA V - - (VREFP + VREFN) / 2 mV - - 2.0 µA - - 2.5 kΩ VDDA / GNDA VOLTAGE REFERENCE CREF c ANALOG INPUT VADCIN VINCM Differential, full-scale analog input voltage, df internal reference g Input common mode voltage, differential mode ± 25 IL RADC CADC RS h ADC input leakage current h ADC equivalent input resistance h ADC equivalent input capacitance h Analog source resistance - - 10 pF - - 500 Ω - 16 SAMPLING DYNAMICS i FADC ADC conversion clock frequency FCONV ADC conversion rate TS - MHz 1 ADC sample time - 250 - 2 j TC ADC conversion time TLT Latency from trigger to start of conversion Msps - ns - ADC clocks LSB 1 µs SYSTEM PERFORMANCE when using internal reference N Resolution 12 bits INL Integral nonlinearity error, over full input range - ±1.5 ±3.0 DNL Differential nonlinearity error, over full input range - ±0.8 +2.0/-1.0 LSB Offset error - ±5.0 ±15.0 LSB - ±10.0 ±30.0 LSB - ±10.0 ±30.0 LSB EO l EG Gain error ET Total unadjusted error, over full input range m k no DYNAMIC CHARACTERISTICS SNRD Signal-to-noise-ratio, Differential input, VADCIN: p -20dB FS, 1KHz 70 72 - dB SDRD Signal-to-distortion ratio, Differential input, pqr VADCIN: -3dB FS, 1KHz 72 75 - dB SNDRD Signal-to-Noise+Distortion ratio, Differential pst input, VADCIN: -3dB FS, 1KHz 68 70 - dB Signal-to-noise-ratio, Single-ended input, VADCIN: -20dB FS, 1KHz 60 65 - dB SNRS u June 12, 2014 1127 Texas Instruments-Production Data Electrical Characteristics Table 21-32. ADC Electrical Characteristics (continued) Parameter Parameter Name Min Nom Max Unit SDRS Signal-to-distortion ratio, Single-ended input, qr VADCIN: -3dB FS, 1KHz 70 72 - dB SNDRS Signal-to-Noise+Distortion ratio, Single-ended stu input, VADCIN: -3dB FS, 1KHz 60 63 - dB TEMPERATURE SENSOR VTSENS Temperature sensor voltage, junction temperature 25 °C - 1.633 - V STSENS Temperature sensor slope - -13.3 - mV/°C - - ±5 °C ETSENS v Temperature sensor accuracy a. VREF+= 3.3V, FADC=16 MHz unless otherwise noted. b. Best design practices suggest that static or quiet digital I/O signals be configured adjacent to sensitive analog inputs to reduce capacitive coupling and cross talk. Analog signals configured adjacent to ADC input channels should meet the same source resistance and bandwidth limitations that apply to the ADC input signals. c. Two capacitors in parallel. d. Internal reference is connected directly between VDDA and GNDA (VREFi = VDDA - GNDA). In this mode, EO, EG, ET, and dynamic specifications are adversely affected due to internal voltage drop and noise on VDDA and GNDA. e. VADCIN = VINP - VINN f. With signal common mode as VDDA/2. g. This parameter is defined as the average of the differential inputs. h. As shown in Figure 21-18 on page 1129, RADC is the total equivalent resistance in the input line all the way up to the sampling node at the input of the ADC. i. See “System Clock Specification with ADC Operation” on page 1118 for full ADC clock frequency specification. j. ADC conversion time (Tc) includes the ADC sample time (Ts). k. 12-bit DNL l. Gain error is measured at max code after compensating for offset. Gain error is equivalent to "Full Scale Error." It can be given in % of slope error, or in LSB, as done here. m. Total Unadjusted Error is the maximum error at any one code versus the ideal ADC curve. It includes all other errors (offset error, gain error and INL) at any given ADC code. n. A low-noise environment is assumed in order to obtain values close to spec. The board must have good ground isolation between analog and digital grounds and a clean reference voltage. The input signal must be band-limited to Nyquist bandwidth. No anti-aliasing filter is provided internally. o. ADC dynamic characteristics are measured using low-noise board design, with low-noise reference voltage ( < -74dB noise level in signal BW) and low-noise analog supply voltage. Board noise and ground bouncing couple into the ADC and affect dynamic characteristics. Clean external reference must be used to achieve shown specs. p. Differential signal with correct common mode, applied between two ADC inputs. q. SDR = -THD in dB. r. For higher frequency inputs, degradation in SDR should be expected. s. SNDR = S/(N+D) = SINAD (in dB) t. Effective number of bits (ENOB) can be calculated from SNDR: ENOB = (SNDR - 1.76) / 6.02. u. Single-ended inputs are more sensitive to board and trace noise than differential inputs; SNR and SNDR measurements on single-ended inputs are highly dependent on how clean the test set-up is. If the input signal is not well-isolated on the board, higher noise than specified could potentially be seen at the ADC output. v. Note that this parameter does not include ADC error. 1128 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 21-18. ADC Input Equivalency Diagram Tiva™ Microcontroller Zs Rs VS ESD clamps   to GND only Input PAD  Equivalent  Circuit ZADC RADC Pin Cs VADCIN 5V ESD  Clamp 12‐bit SAR ADC Converter 12‐bit Word IL Pin Input PAD  Equivalent  Circuit Pin Input PAD  Equivalent  Circuit RADC RADC CADC June 12, 2014 1129 Texas Instruments-Production Data Electrical Characteristics 21.15 Synchronous Serial Interface (SSI) Table 21-33. SSI Characteristics Parameter No. Parameter Parameter Name Min Nom Max Unit S1 TCLK_PER 40 - - ns SSIClk cycle time, as slave 150 - - ns S2 TCLK_HIGH SSIClk high time, as master 20 - - ns SSIClk high time, as slave 75 - - ns S3 TCLK_LOW SSIClk low time, as master 20 - - ns S4 TCLKR SSIClk rise time 75 - - ns 1.25 - - S5 TCLKF c ns 1.25 - - ns S6 TTXDMOV Master Mode: Master Tx Data Output (to slave) Valid Time from edge of SSIClk - - 15.7 ns S7 TTXDMOH Master Mode: Master Tx Data Output (to slave) Hold Time from next SSIClk 0.31 - - ns S8 TRXDMS Master Mode: Master Rx Data In (from slave) setup time 17.15 - - ns S9 TRXDMH Master Mode: Master Rx Data In (from slave) hold time 0 - - ns S10 TTXDSOV Slave Mode: Master Tx Data Output (to Master) Valid Time from edge of SSIClk - - 77.74 ns S11 TTXDSOH Slave Mode: Slave Tx Data Output (to Master) Hold Time from next SSIClk 55.5 - - ns S12 TRXDSSU Slave Mode: Rx Data In (from master) setup time - - ns - - ns a S13 TRXDSH SSIClk cycle time, as master b SSIClk low time, as slave c SSIClk fall time Slave Mode: Rx Data In (from master) hold time e 0 f 51.55 d a. In master mode, the system clock must be at least twice as fast as the SSIClk. b. In slave mode, the system clock must be at least 12 times faster than the SSIClk. c. Note that the delays shown are using 8-mA drive strength. d. This MAX value is for the minimum TSYSCLK (12.5 ns). To find the MAX TTXDSOV value for a larger TSYSCLK, use the equation: 4*TSYSCLK+27.74. e. This MIN value is for the minimum slave mode TSYSCLK (12.5 ns). To find the MIN TTXDSOH value for a larger TSYSCLK, use the equation: 4*TSYSCLK+5.50. f. This MIN value is for the minimum slave mode TSYSCLK (12.5 ns). To find the MIN TRXDSH value for a larger TSYSCLK, use the equation: 4*TSYSCLK+1.55. 1130 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Figure 21-19. SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing Measurement S1 S2 S4 S5 SSIClk S3 SSIFss SSITx SSIRx MSB LSB 4 to 16 bits Figure 21-20. SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer S2 S1 S5 S4 SSIClk S3 SSIFss SSITx MSB LSB 8-bit control SSIRx 0 MSB LSB 4 to 16 bits output data June 12, 2014 1131 Texas Instruments-Production Data Electrical Characteristics Figure 21-21. Master Mode SSI Timing for SPI Frame Format (FRF=00), with SPH=1 S1 S5 S2 S4 SSIClk (SPO=1) S3 SSIClk (SPO=0) S7 S6 SSITx MSB (to slave) S8 SSIRx LSB S9 MSB ( from slave) LSB SSIFss Figure 21-22. Slave Mode SSI Timing for SPI Frame Format (FRF=00), with SPH=1 S1 S5 S4 S2 SSIClk (SPO=1) S3 S3 SSIClk (SPO=0) S10 SSITx S11 MSB (to master) LSB S12 S13 SSIRx ( from master) MSB LSB SSIFss 1132 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller 21.16 Inter-Integrated Circuit (I2C) Interface Table 21-34. I2C Characteristics Parameter No. Parameter Parameter Name Min Nom Max Unit a TSCH Start condition hold time 36 - - system clocks a TLP Clock Low period 36 - - system clocks b I3 TSRT I2CSCL/I2CSDA rise time (VIL =0.5 V to V IH =2.4 V) - - (see note b) ns I4 TDH Data hold time (slave) - 2 - system clocks Data hold time (master) - 7 - system clocks c TSFT I2CSCL/I2CSDA fall time (VIH =2.4 V to V IL =0.5 V) - 9 10 ns a THT Clock High time 24 - - system clocks I1 I2 I5 I6 I7 Data setup time 18 - - system clocks a TSCSR Start condition setup time (for repeated start condition only) 36 - - system clocks I9 a TSCS Stop condition setup time 24 - - system clocks Data Valid (slave) - 2 - system clocks I10 TDV Data Valid (master) - (6 * (1 + TPR)) + 1 - system clocks I8 TDS a. Values depend on the value programmed into the TPR bit in the I2C Master Timer Period (I2CMTPR) register; a TPR programmed for the maximum I2CSCL frequency (TPR=0x2) results in a minimum output timing as shown in the table above. The I 2C interface is designed to scale the actual data transition time to move it to the middle of the I2CSCL Low period. The actual position is affected by the value programmed into the TPR; however, the numbers given in the above values are minimum values. b. Because I2CSCL and I2CSDA operate as open-drain-type signals, which the controller can only actively drive Low, the time I2CSCL or I2CSDA takes to reach a high level depends on external signal capacitance and pull-up resistor values. c. Specified at a nominal 50 pF load. Figure 21-23. I2C Timing I2 I10 I6 I5 I2CSCL I1 I4 I7 I8 I3 I9 I2CSDA June 12, 2014 1133 Texas Instruments-Production Data Electrical Characteristics 21.17 Analog Comparator ab Table 21-35. Analog Comparator Characteristics Parameter Parameter Name c VINP,VINN VCM VOS IINP,IINN CMRR Min Nom Max Unit Input voltage range GNDA - VDDA V Input common mode voltage range GNDA - VDDA V d Input offset voltage - ±10 ±50 mV Input leakage current over full voltage range - - 2.0 µA Common mode rejection ratio - 50 - dB e TRT Response time - - 1.0 µs TMC Comparator mode change to Output Valid - - 10 µs a. Best design practices suggest that static or quiet digital I/O signals be configured adjacent to sensitive analog inputs to reduce capacitive coupling and cross talk. b. To achieve best analog results, the source resistance driving the analog inputs, VINP and VINN, should be kept low. c. The external voltage inputs to the Analog Comparator are designed to be highly sensitive and can be affected by external noise on the board. For this reason, VINP and VINN must be set to different voltage levels during idle states to ensure the analog comparator triggers are not enabled. If an internal voltage reference is used, it should be set to a mid-supply level. When operating in Sleep/Deep-Sleep modes, the Analog Comparator module external voltage inputs set to different levels (greater than the input offset voltage) to achieve minimum current draw. d. Measured at VREF=100 mV. e. Measured at external VREF=100 mV, input signal switching from 75 mV to 125 mV. Table 21-36. Analog Comparator Voltage Reference Characteristics Parameter Parameter Name Min Nom Max Unit RHR Resolution in high range - VDDA/29.4 - V RLR Resolution in low range - VDDA/22.12 - V AHR Absolute accuracy high range - - ±RHR/2 V ALR Absolute accuracy low range - - ±RLR/2 V Table 21-37. Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 0 VREF Value VIREF Min Ideal VIREF VIREF Max Unit 0x0 0.731 0.786 0.841 V 0x1 0.843 0.898 0.953 V 0x2 0.955 1.010 1.065 V 0x3 1.067 1.122 1.178 V 0x4 1.180 1.235 1.290 V 0x5 1.292 1.347 1.402 V 0x6 1.404 1.459 1.514 V 0x7 1.516 1.571 1.627 V 0x8 1.629 1.684 1.739 V 0x9 1.741 1.796 1.851 V 0xA 1.853 1.908 1.963 V 0xB 1.965 2.020 2.076 V 0xC 2.078 2.133 2.188 V 1134 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 21-37. Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 0 (continued) VREF Value VIREF Min Ideal VIREF VIREF Max Unit 0xD 2.190 2.245 2.300 V 0xE 2.302 2.357 2.412 V 0xF 2.414 2.469 2.525 V Table 21-38. Analog Comparator Voltage Reference Characteristics, VDDA = 3.3V, EN= 1, and RNG = 1 VREF Value VIREF Min Ideal VIREF VIREF Max Unit 0x0 0.000 0.000 0.074 V 0x1 0.076 0.149 0.223 V 0x2 0.225 0.298 0.372 V 0x3 0.374 0.448 0.521 V 0x4 0.523 0.597 0.670 V 0x5 0.672 0.746 0.820 V 0x6 0.822 0.895 0.969 V 0x7 0.971 1.044 1.118 V 0x8 1.120 1.193 1.267 V 0x9 1.269 1.343 1.416 V 0xA 1.418 1.492 1.565 V 0xB 1.567 1.641 1.715 V 0xC 1.717 1.790 1.864 V 0xD 1.866 1.939 2.013 V 0xE 2.015 2.089 2.162 V 0xF 2.164 2.238 2.311 V June 12, 2014 1135 Texas Instruments-Production Data Electrical Characteristics 21.18 Current Consumption Table 21-39. Current Consumption System Clock Parameter Parameter Name Conditions VDD = 3.3 V VDDA = 3.3 V VDD = 3.3 V VDDA = 3.3 V VDD = 3.3 V VDDA = 3.3 V VDD = 3.3 V VDDA = 3.3 V a IDDA VDD = 3.3 V Deep-Sleep mode Peripherals = All ON Run, Sleep and Deep-sleep mode VDD = 3.3 V Peripherals = All OFF mA 32.0 32.7 40.6 mA 19.6 19.7 20.3 27.6 mA PIOSC 17.5 17.6 18.0 25.3 mA 45.0 45.1 40 MHz MOSC with PLL 31.9 16 MHz MOSC with PLL 16 MHz -40°C 25°C 85°C 1 MHz PIOSC 10.0 10.1 10.5 17.5 mA 80 MHz MOSC with PLL 24.5 24.7 25.2 31.3 mA 40 MHz MOSC with PLL 19.6 19.7 20.4 25.9 mA 16 MHz MOSC with PLL 12.1 12.2 12.7 18.7 mA 16 MHz PIOSC 10.1 10.1 10.5 16.4 mA 1 MHz PIOSC 5.45 5.50 5.98 11.6 mA 80 MHz MOSC with PLL 34.7 34.9 35.5 44.2 mA 40 MHz MOSC with PLL 22.2 22.4 22.9 30.2 mA 16 MHz MOSC with PLL 14.7 14.8 15.3 21.8 mA 16 MHz PIOSC 12.8 12.9 13.4 19.7 mA 1 MHz PIOSC 8.07 8.16 8.61 14.6 mA 80 MHz MOSC with PLL 15.2 15.3 15.8 21.7 mA 40 MHz MOSC with PLL 10.3 10.5 10.9 16.2 mA 16 MHz MOSC with PLL 7.32 7.45 7.92 13.0 mA 16 MHz PIOSC 5.87 5.96 6.35 13.7 mA 1 MHz PIOSC 3.54 3.63 4.07 8.84 mA - MOSC with PLL, PIOSC 2.71 2.71 2.71 3.97 mA 30 kHz LFIOSC 2.54 2.54 2.54 3.68 mA - MOSC with PLL, PIOSC, LFIOSC 0.28 0.28 0.29 0.56 mA VDDA = 3.3 V VDDA = 3.3 V 54.9 MOSC with PLL Peripherals = All OFF Run, Sleep and Deep-sleep mode 45.7 80 MHz Peripherals = All ON Run mode (SRAM loop) Unit Clock Source Peripherals = All OFF IDD_RUN Max 85°C Frequency Peripherals = All ON Run mode (Flash loop) Nom 1136 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller Table 21-39. Current Consumption (continued) System Clock Parameter Parameter Name Conditions VDD = 3.3 V Sleep mode (FLASHPM = 0x0) VDD = 3.3 V VDD = 3.3 V VDD = 3.3 V 20.2 27.1 mA 13.6 13.8 14.2 20.6 mA b 11.7 11.8 12.2 18.5 mA b 40 MHz MOSC with PLL 19.5 16 MHz MOSC with PLL 16 MHz PIOSC -40°C 25°C 85°C 1 MHz PIOSC 7.01 7.06 7.93 12.0 mA 80 MHz MOSC with PLL 9.60 9.73 10.2 15.4 mA 40 MHz MOSC with PLL 7.49 7.60 8.06 13.2 mA 16 MHz MOSC with PLL 6.22 6.33 6.78 11.7 mA 16 MHz PIOSC b 4.28 4.35 4.77 9.52 mA b 1 MHz PIOSC 3.52 3.59 4.01 8.70 mA 80 MHz MOSC with PLL 28.4 28.6 29.2 37.2 mA 40 MHz MOSC with PLL 18.6 18.8 19.3 26.2 mA 16 MHz MOSC with PLL 12.7 12.9 13.3 19.7 mA 16 MHz PIOSC b 10.8 10.9 11.3 17.5 mA b 1 MHz PIOSC 7.09 7.20 7.67 13.6 mA 80 MHz MOSC with PLL 8.66 8.82 9.31 14.5 mA 40 MHz MOSC with PLL 6.55 6.69 7.17 12.1 mA 16 MHz MOSC with PLL 5.27 5.41 5.89 10.7 mA 16 MHz PIOSC b 3.34 3.44 3.88 8.65 mA 1 MHz PIOSC b 2.58 2.67 3.13 7.85 mA VDDA = 3.3 V Peripherals = All OFF 19.7 29.5 LDO = 1.2 V Sleep mode (FLASHPM = 0x2) mA 29.3 VDDA = 3.3 V Peripherals = All ON 38.1 MOSC with PLL LDO = 1.2 V IDD_SLEEP 30.0 80 MHz VDDA = 3.3 V Peripherals = All OFF Unit Clock Source LDO = 1.2 V Max 85°C Frequency VDDA = 3.3 V Peripherals = All ON Nom LDO = 1.2 V June 12, 2014 1137 Texas Instruments-Production Data Electrical Characteristics Table 21-39. Current Consumption (continued) System Clock Parameter Parameter Name Nom Conditions Frequency VDD = 3.3 V 16 MHz PIOSC 9.29 9.29 VDDA = 3.3 V 30 kHz LFIOSC 5.10 5.10 VDD = 3.3 V 16 MHz PIOSC 3.51 VDDA = 3.3 V 30 kHz LFIOSC Clock Source Max 85°C Unit 9.66 15.9 mA 5.48 11.2 mA 3.51 3.91 8.67 mA 2.00 2.00 2.39 7.24 mA -40°C 25°C 85°C Peripherals = All ON Deep-sleep mode (FLASHPM = 0x0) LDO = 1.2 V Peripherals = All OFF LDO = 1.2 V IDD_DEEPSLEEP VDD = 3.3 V 16 MHz PIOSC 8.34 8.36 8.77 14.9 mA VDDA = 3.3 V 30 kHz LFIOSC 4.14 4.18 4.59 10.4 mA VDD = 3.3 V 16 MHz PIOSC 2.56 2.60 3.02 7.79 mA VDDA = 3.3 V 30 kHz LFIOSC 1.04 1.07 1.49 6.48 mA - - 1.23 1.38 1.54 5.20 µA - - 1.27 1.40 1.69 5.24 µA - - 3.17 4.49 10.6 28.1 µA - - 3.16 4.33 10.4 27.7 µA Peripherals = All ON Deep-sleep mode (FLASHPM = 0x2) LDO = 1.2 V Peripherals = All OFF LDO = 1.2 V IHIB_NORTC Hibernate mode (external wake, RTC disabled) VBAT = 3.0 V VDD = 0 V VDDA = 0 V System Clock = OFF Hibernate Module = 32.768 kHz IHIB_RTC Hibernate mode (RTC enabled) VBAT = 3.0 V VDD = 0 V VDDA = 0 V System Clock = OFF Hibernate Module = 32.768 kHz Hibernate mode (VDD3ON mode, RTC on) VBAT = 3.0 V VDD = 3.3 V VDDA = 3.3 V System Clock = OFF IHIB_VDD3ON Hibernate Module = 32.768 kHz Hibernate mode (VDD3ON mode, RTC off) VBAT = 3.0 V VDD = 3.3 V VDDA = 3.3 V System Clock = OFF Hibernate Module = 32.768 kHz a. The value for IDDA is included in the above values for IDD_RUN, IDD_SLEEP, and IDD_DEEPSLEEP. b. Note that if the MOSC is the source of the Run-mode system clock and is powered down in Sleep mode, wake time is increased by TMOSC_SETTLE. 1138 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller A Package Information A.1 Orderable Devices The figure below defines the full set of orderable part numbers for the TM4C123x Series. See the Package Option Addendum for the complete list of valid orderable part numbers for the TM4C1231H6PM microcontroller. Figure A-1. Key to Part Numbers T M4 C 1 SSS M Y PPP T XX Z R Shipping Medium R = Tape-and-reel Omitted = Default shipping (tray or tube) Prefix T = Qualified Device X = Experimental Device Revision Core M4 = ARM® Cortex™-M4 Special Codes Optional Tiva Series C = Connected MCUs Temperature I = –40°C to +85°C T = –40°C to +105°C Package PM = 64-pin LQFP PZ = 100-pin LQFP PGE = 144-pin LQFP ZRB = 157-ball BGA Data Memory 3 = 12 KB 5 = 24 KB 6 = 32 KB Family Part Number SSS = Series identifier Program Memory C = 32 KB D = 64 KB E = 128 KB H = 256 KB A.2 Device Nomenclature To designate the stages in the product development cycle, TI assigns prefixes to the part numbers of all microcontroller (MCU) devices. Each Tiva™ C Series family member has one of two prefixes: XM4C or TM4C. These prefixes represent evolutionary stages of product development from engineering prototypes (XM4C) through fully qualified production devices (TM4C). Device development evolutionary flow: ■ XM4C — Experimental device that is not necessarily representative of the final device's electrical specifications and may not use production assembly flow. ■ TM4C — Production version of the silicon die that is fully qualified. XM4C devices are shipped against the following disclaimer: "Developmental product is intended for internal evaluation purposes." TM4C devices have been characterized fully, and the quality and reliability of the device have been demonstrated fully. TI's standard warranty applies. Predictions show that prototype devices (XM4C) have a greater failure rate than the standard production devices. Texas Instruments recommends that these devices not be used in any production system because their expected end-use failure rate still is undefined. Only qualified production devices are to be used. June 12, 2014 1139 Texas Instruments-Production Data Package Information A.3 Device Markings The figure below shows an example of the Tiva™ microcontroller package symbolization. $$ TM4C123G H6PGEI7 YMLLLLS G1 This identifying number contains the following information: ■ Lines 1 and 5: Internal tracking numbers ■ Lines 2 and 3: Part number For example, TM4C123G on the second line followed by H6PGEI7 on the third line indicates orderable part number TM4C123GH6PGEI7. The silicon revision number is the last number in the part number, in this example, 7. The DID0 register also identifies the version of the microcontroller, as shown in the table below. Combined, the MAJOR and MINOR bit fields indicate the die revision and part revision numbers. MAJOR Bitfield Value MINOR Bitfield Value Die Revision Part Revision 0x0 0x0 A0 1 0x0 0x1 A1 2 0x0 0x2 A2 3 0x0 0x3 A3 4 0x1 0x0 B0 5 0x1 0x1 B1 6 0x1 0x2 B2 7 ■ Line 4: Date code The first two characters on the fourth line indicate the date code, followed by internal tracking numbers. The two-digit date code YM indicates the last digit of the year, then the month. For example, a 34 for the first two digits of the fourth line indicates a date code of April 2013. 1140 June 12, 2014 Texas Instruments-Production Data Tiva™ TM4C1231H6PM Microcontroller A.4 Packaging Diagram Figure A-2. TM4C1231H6PM 64-Pin LQFP Package Diagram MECHANICAL DATA MTQF008A – JANUARY 1995 – REVISED DECEMBER 1996 PM (S-PQFP-G64) PLASTIC QUAD FLATPACK 0,27 0,17 0,50 0,08 M 33 48 49 32 64 17 0,13 NOM 1 16 7,50 TYP 10,20 SQ 9,80 12,20 SQ 11,80 Gage Plane 0,25 0,05 MIN 0°– 7° 0,75 0,45 1,45 1,35 Seating Plane 1,60 MAX 0,08 4040152 / C 11/96 NOTES: A. B. C. D. All linear dimensions are in millimeters. This drawing is subject to change without notice. Falls within JEDEC MS-026 May also be thermally enhanced plastic with leads connected to the die pads. June 12, 2014 1141 Texas Instruments-Production Data PACKAGE OPTION ADDENDUM www.ti.com 2-Mar-2021 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) TM4C1231H6PMI ACTIVE LQFP PM 64 160 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 TM4C1231 H6PMI TM4C1231H6PMI7 ACTIVE LQFP PM 64 160 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 TM4C1231 H6PMI7 TM4C1231H6PMI7R ACTIVE LQFP PM 64 1000 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 TM4C1231 H6PMI7 TM4C1231H6PMIR ACTIVE LQFP PM 64 1000 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 TM4C1231 H6PMI (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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