C8051F537-C-ITR

C8051F52x/F53x 8/4/2 kB ISP Flash MCU Family Analog Peripherals - 12-Bit ADC • Programmable throughput up to 200 ksps • Up to 6/16 external inputs • Data dependent windowed interrupt generator • Built-in temperature sensor - Comparator • Programmable hysteresis and response time • Configurable as wake-up or reset source • Low current - POR/Brownout Detector - Voltage Reference—1.5 and 2.2 V Memory - 8/4/2 kB Flash; In-system byte programmable in 512 byte sectors - 256 bytes internal data RAM Digital Peripherals - 16/6 port I/O; push-pull or open-drain, 5 V tolerant - Hardware SPI™, and UART serial port - LIN 2.1 Controller (Master and Slave capable); no - intrusive in-system debug (No emulator required) - Provides breakpoints, single stepping - Inspect/modify memory and registers - Complete development kit Supply Voltage 2.0 to 5.25 V - Built-in LDO regulator High-Speed 8051 µC Core - Pipelined instruction architecture; executes 70% of - instructions in 1 or 2 system clocks Up to 25 MIPS throughput with 25 MHz system clock Expanded interrupt handler ANALOG PERIPHERALS A M U X 12-bit 200 ksps ADC TEMP SENSOR + VOLTAGE COMPARATOR VREF Clock Sources - Internal oscillators: 24.5 MHz ±0.5% accuracy sup- ports UART and LIN-Master operation External oscillator: Crystal, RC, C, or Clock (1 or 2 pin modes) Can switch between clock sources on-the-fly Packages - 10-Pin DFN (3 x 3 mm) - 20-pin QFN (4 x 4 mm) - 20-pin TSSOP Automotive Qualified - Temperature Range: –40 to +125 °C - Compliant to AEC-Q100 DIGITAL I/O UART SPI PCA Timer 0 Timer 1 Timer 2 Port 0 CROSSBAR (programmable) On-Chip Debug - On-chip debug circuitry facilitates full-speed, non- crystal required Three general purpose 16-bit counter/timers Programmable 16-bit counter/timer array with three capture/compare modules, WDT Port 1 LIN VREG 24.5 MHz High Precision (±0.5%) Internal Oscillator HIGH-SPEED CONTROLLER CORE 8/4/2 kB ISP FLASH FLEXIBLE INTERRUPTS Rev. 1.4 4/12 8051 CPU (25 MIPS) DEBUG CIRCUITRY 256 B SRAM POR Copyright © 2012 by Silicon Laboratories WDT C8051F52x/F53x C8051F52x/F52xA/F53x/F53xA 2 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table of Contents 1. System Overview ..................................................................................................... 13 1.1. Ordering Information.......................................................................................... 14 1.2. CIP-51™ Microcontroller ................................................................................... 18 1.2.1. Fully 8051 Compatible Instruction Set ...................................................... 18 1.2.2. Improved Throughput................................................................................ 18 1.2.3. Additional Features ................................................................................... 18 1.2.4. On-Chip Debug Circuitry ........................................................................... 18 1.3. On-Chip Memory ............................................................................................... 20 1.4. Operating Modes ............................................................................................... 21 1.5. 12-Bit Analog to Digital Converter ..................................................................... 22 1.6. Programmable Comparator ............................................................................... 23 1.7. Voltage Regulator.............................................................................................. 23 1.8. Serial Port.......................................................................................................... 23 1.9. Port Input/Output ............................................................................................... 24 2. Electrical Characteristics ........................................................................................ 25 2.1. Absolute Maximum Ratings............................................................................... 25 2.2. Electrical Characteristics ................................................................................... 26 3. Pinout and Package Definitions ............................................................................. 35 4. 12-Bit ADC (ADC0) ................................................................................................... 52 4.1. Analog Multiplexer ............................................................................................. 52 4.2. Temperature Sensor.......................................................................................... 53 4.3. ADC0 Operation ................................................................................................ 54 4.3.1. Starting a Conversion................................................................................ 54 4.3.2. Tracking Modes......................................................................................... 54 4.3.3. Timing ....................................................................................................... 55 4.3.4. Burst Mode................................................................................................ 57 4.3.5. Output Conversion Code........................................................................... 59 4.3.6. Settling Time Requirements...................................................................... 60 4.4. Selectable Gain ................................................................................................. 60 4.4.1. Calculating the Gain Value........................................................................ 61 4.4.2. Setting the Gain Value .............................................................................. 62 4.5. Programmable Window Detector....................................................................... 69 4.5.1. Window Detector In Single-Ended Mode .................................................. 71 5. Voltage Reference.................................................................................................... 72 6. Voltage Regulator (REG0) ....................................................................................... 74 7. Comparator ............................................................................................................. 76 8. CIP-51 Microcontroller............................................................................................. 81 8.1. Instruction Set.................................................................................................... 82 8.1.1. Instruction and CPU Timing ...................................................................... 82 8.1.2. MOVX Instruction and Program Memory .................................................. 83 8.2. Register Descriptions ........................................................................................ 86 8.3. Power Management Modes............................................................................... 89 8.3.1. Idle Mode .................................................................................................. 90 Rev. 1.4 3 C8051F52x/F52xA/F53x/F53xA 8.3.2. Stop Mode................................................................................................. 90 8.3.3. Suspend Mode .......................................................................................... 90 9. Memory Organization and SFRs............................................................................. 92 9.1. Program Memory............................................................................................... 92 9.2. Data Memory ..................................................................................................... 93 9.3. General Purpose Registers ............................................................................... 93 9.4. Bit Addressable Locations ................................................................................. 93 9.5. Stack ............................................................................................................ 93 9.6. Special Function Registers................................................................................ 93 10. Interrupt Handler.................................................................................................... 98 10.1. MCU Interrupt Sources and Vectors................................................................ 98 10.2. Interrupt Priorities ............................................................................................ 98 10.3. Interrupt Latency.............................................................................................. 98 10.4. Interrupt Register Descriptions ...................................................................... 100 10.5. External Interrupts ......................................................................................... 104 11. Reset Sources ...................................................................................................... 106 11.1. Power-On Reset ............................................................................................ 107 11.2. Power-Fail Reset / VDD Monitors (VDDMON0 and VDDMON1) .................. 108 11.2.1. VDD Monitor Thresholds and Minimum VDD........................................ 108 11.3. External Reset ............................................................................................... 110 11.4. Missing Clock Detector Reset ....................................................................... 110 11.5. Comparator Reset ......................................................................................... 110 11.6. PCA Watchdog Timer Reset ......................................................................... 110 11.7. Flash Error Reset .......................................................................................... 110 11.8. Software Reset .............................................................................................. 111 12. Flash Memory....................................................................................................... 113 12.1. Programming The Flash Memory .................................................................. 113 12.1.1. Flash Lock and Key Functions .............................................................. 113 12.1.2. Flash Erase Procedure ......................................................................... 114 12.1.3. Flash Write Procedure .......................................................................... 114 12.2. Flash Write and Erase Guidelines ................................................................. 115 12.2.1. VDD Maintenance and the VDD monitor ................................................ 115 12.2.2. PSWE Maintenance .............................................................................. 115 12.2.3. System Clock ........................................................................................ 116 12.3. Non-volatile Data Storage ............................................................................. 117 12.4. Security Options ............................................................................................ 117 13. Port Input/Output ................................................................................................. 120 13.1. Priority Crossbar Decoder ............................................................................. 122 13.2. Port I/O Initialization ...................................................................................... 126 13.3. General Purpose Port I/O .............................................................................. 128 14. Oscillators ............................................................................................................ 135 14.1. Programmable Internal Oscillator .................................................................. 135 14.1.1. Internal Oscillator Suspend Mode ......................................................... 136 14.2. External Oscillator Drive Circuit..................................................................... 139 14.2.1. Clocking Timers Directly Through the External Oscillator..................... 139 4 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 14.2.2. External Crystal Example...................................................................... 139 14.2.3. External RC Example............................................................................ 141 14.2.4. External Capacitor Example.................................................................. 141 14.3. System Clock Selection................................................................................. 143 15. UART0 ................................................................................................................... 144 15.1. Enhanced Baud Rate Generation.................................................................. 145 15.2. Operational Modes ........................................................................................ 146 15.2.1. 8-Bit UART ............................................................................................ 146 15.2.2. 9-Bit UART ............................................................................................ 147 15.3. Multiprocessor Communications ................................................................... 148 16. Enhanced Serial Peripheral Interface (SPI0) ..................................................... 151 16.1. Signal Descriptions........................................................................................ 152 16.1.1. Master Out, Slave In (MOSI)................................................................. 152 16.1.2. Master In, Slave Out (MISO)................................................................. 152 16.1.3. Serial Clock (SCK) ................................................................................ 152 16.1.4. Slave Select (NSS) ............................................................................... 152 16.2. SPI0 Master Mode Operation ........................................................................ 153 16.3. SPI0 Slave Mode Operation .......................................................................... 154 16.4. SPI0 Interrupt Sources .................................................................................. 155 16.5. Serial Clock Timing........................................................................................ 156 16.6. SPI Special Function Registers ..................................................................... 156 17. LIN (C8051F520/0A/3/3A/6/6A and C8051F530/0A/3/3A/6/6A) .......................... 164 17.1. Software Interface with the LIN Peripheral .................................................... 165 17.2. LIN Interface Setup and Operation................................................................ 165 17.2.1. Mode Definition ..................................................................................... 165 17.2.2. Baud Rate Options: Manual or Autobaud ............................................. 165 17.2.3. Baud Rate Calculations—Manual Mode ............................................... 165 17.2.4. Baud Rate Calculations—Automatic Mode ........................................... 168 17.3. LIN Master Mode Operation .......................................................................... 169 17.4. LIN Slave Mode Operation ............................................................................ 170 17.5. Sleep Mode and Wake-Up ............................................................................ 171 17.6. Error Detection and Handling ........................................................................ 171 17.7. LIN Registers................................................................................................. 172 17.7.1. LIN Direct Access SFR Registers Definition ......................................... 172 17.7.2. LIN Indirect Access SFR Registers Definition....................................... 174 18. Timers ................................................................................................................... 182 18.1. Timer 0 and Timer 1 ...................................................................................... 182 18.1.1. Mode 0: 13-bit Counter/Timer ............................................................... 182 18.1.2. Mode 1: 16-bit Counter/Timer ............................................................... 184 18.1.3. Mode 2: 8-bit Counter/Timer with Auto-Reload..................................... 184 18.1.4. Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)................................ 185 18.2. Timer 2 .......................................................................................................... 190 18.2.1. 16-bit Timer with Auto-Reload............................................................... 190 18.2.2. 8-bit Timers with Auto-Reload............................................................... 191 18.2.3. External Capture Mode ......................................................................... 192 Rev. 1.4 5 C8051F52x/F52xA/F53x/F53xA 19. Programmable Counter Array (PCA0)................................................................ 195 19.1. PCA Counter/Timer ....................................................................................... 196 19.2. Capture/Compare Modules ........................................................................... 197 19.2.1. Edge-triggered Capture Mode............................................................... 198 19.2.2. Software Timer (Compare) Mode.......................................................... 199 19.2.3. High Speed Output Mode...................................................................... 200 19.2.4. Frequency Output Mode ....................................................................... 201 19.2.5. 8-Bit Pulse Width Modulator Mode........................................................ 202 19.2.6. 16-Bit Pulse Width Modulator Mode...................................................... 203 19.3. Watchdog Timer Mode .................................................................................. 203 19.3.1. Watchdog Timer Operation ................................................................... 204 19.3.2. Watchdog Timer Usage ........................................................................ 205 19.4. Register Descriptions for PCA....................................................................... 206 20. Device Specific Behavior .................................................................................... 210 20.1. Device Identification ...................................................................................... 210 20.2. Reset Pin Behavior........................................................................................ 211 20.3. Reset Time Delay .......................................................................................... 211 20.4. VDD Monitors and VDD Ramp Time ............................................................. 211 20.5. VDD Monitor (VDDMON0) High Threshold Setting ....................................... 212 20.6. Reset Low Time............................................................................................. 212 20.7. Internal Oscillator Suspend Mode ................................................................. 212 20.8. UART Pins..................................................................................................... 213 20.9. LIN ................................................................................................................. 213 20.9.1. Stop Bit Check ...................................................................................... 213 20.9.2. Synch Break and Synch Field Length Check........................................ 213 21. C2 Interface .......................................................................................................... 214 21.1. C2 Interface Registers................................................................................... 214 21.2. C2 Pin Sharing .............................................................................................. 216 Document Change List.............................................................................................. 217 Contact Information................................................................................................... 220 6 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA List of Figures Figure 1.1. C8051F53xA/F53x-C Block Diagram .................................................... 16 Figure 1.2. C8051F52xA/F52x-C Block Diagram .................................................... 16 Figure 1.3. C8051F53x Block Diagram (Silicon Revision A) ................................... 17 Figure 1.4. C8051F52x Block Diagram (Silicon Revision A) ................................... 17 Figure 1.5. Development/In-System Debug Diagram .............................................. 19 Figure 1.6. Memory Map ......................................................................................... 20 Figure 1.7. 12-Bit ADC Block Diagram .................................................................... 22 Figure 1.8. Comparator Block Diagram ................................................................... 23 Figure 1.9. Port I/O Functional Block Diagram ........................................................ 24 Figure 3.1. DFN-10 Pinout Diagram (Top View) ...................................................... 35 Figure 3.2. DFN-10 Package Diagram .................................................................... 38 Figure 3.3. DFN-10 Landing Diagram ..................................................................... 39 Figure 3.4. TSSOP-20 Pinout Diagram (Top View) ................................................. 40 Figure 3.5. TSSOP-20 Package Diagram ............................................................... 43 Figure 3.6. TSSOP-20 Landing Diagram ................................................................. 44 Figure 3.7. QFN-20 Pinout Diagram (Top View) ..................................................... 45 Figure 3.8. QFN-20 Package Diagram* ................................................................... 48 Figure 3.9. QFN-20 Landing Diagram* .................................................................... 50 Figure 4.1. ADC0 Functional Block Diagram ........................................................... 52 Figure 4.2. Typical Temperature Sensor Transfer Function .................................... 53 Figure 4.3. ADC0 Tracking Modes .......................................................................... 55 Figure 4.4. 12-Bit ADC Tracking Mode Example ..................................................... 56 Figure 4.5. 12-Bit ADC Burst Mode Example with Repeat Count Set to 4 .............. 58 Figure 4.6. ADC0 Equivalent Input Circuits ............................................................. 60 Figure 4.7. ADC Window Compare Example: Right-Justified Single-Ended Data ........................................................ 71 Figure 4.8. ADC Window Compare Example: Left-Justified Single-Ended Data .......................................................... 71 Figure 5.1. Voltage Reference Functional Block Diagram ....................................... 72 Figure 6.1. External Capacitors for Voltage Regulator Input/Output ....................... 74 Figure 7.1. Comparator Functional Block Diagram ................................................. 76 Figure 7.2. Comparator Hysteresis Plot .................................................................. 77 Figure 8.1. CIP-51 Block Diagram ........................................................................... 81 Figure 9.1. Memory Map ......................................................................................... 92 Figure 11.1. Reset Sources ................................................................................... 106 Figure 11.2. Power-On and VDD Monitor Reset Timing ........................................ 107 Figure 12.1. Flash Program Memory Map ............................................................. 117 Figure 13.1. Port I/O Functional Block Diagram .................................................... 120 Figure 13.2. Port I/O Cell Block Diagram .............................................................. 121 Figure 13.3. Crossbar Priority Decoder with No Pins Skipped (TSSOP 20 and QFN 20) .................................................................. 122 Figure 13.4. Crossbar Priority Decoder with Crystal Pins Skipped (TSSOP 20 and QFN 20) .................................................................. 123 Rev. 1.4 7 C8051F52x/F52xA/F53x/F53xA Figure 13.5. Crossbar Priority Decoder with No Pins Skipped (DFN 10) .............. 124 Figure 13.6. Crossbar Priority Decoder with Some Pins Skipped (DFN 10) ......... 125 Figure 14.1. Oscillator Diagram ............................................................................. 135 Figure 14.2. 32 kHz External Crystal Example ...................................................... 140 Figure 15.1. UART0 Block Diagram ...................................................................... 144 Figure 15.2. UART0 Baud Rate Logic ................................................................... 145 Figure 15.3. UART Interconnect Diagram ............................................................. 146 Figure 15.4. 8-Bit UART Timing Diagram .............................................................. 146 Figure 15.5. 9-Bit UART Timing Diagram .............................................................. 147 Figure 15.6. UART Multi-Processor Mode Interconnect Diagram ......................... 148 Figure 16.1. SPI Block Diagram ............................................................................ 151 Figure 16.2. Multiple-Master Mode Connection Diagram ...................................... 154 Figure 16.3. 3-Wire Single Master and Slave Mode Connection Diagram ............ 154 Figure 16.4. 4-Wire Single Master and Slave Mode Connection Diagram ............ 154 Figure 16.5. Data/Clock Timing Relationship ........................................................ 156 Figure 16.6. SPI Master Timing (CKPHA = 0) ....................................................... 161 Figure 16.7. SPI Master Timing (CKPHA = 1) ....................................................... 161 Figure 16.8. SPI Slave Timing (CKPHA = 0) ......................................................... 162 Figure 16.9. SPI Slave Timing (CKPHA = 1) ......................................................... 162 Figure 17.1. LIN Block Diagram ............................................................................ 164 Figure 18.1. T0 Mode 0 Block Diagram ................................................................. 183 Figure 18.2. T0 Mode 2 Block Diagram ................................................................. 184 Figure 18.3. T0 Mode 3 Block Diagram ................................................................. 185 Figure 18.4. Timer 2 16-Bit Mode Block Diagram ................................................. 190 Figure 18.5. Timer 2 8-Bit Mode Block Diagram ................................................... 191 Figure 18.6. Timer 2 Capture Mode Block Diagram .............................................. 192 Figure 19.1. PCA Block Diagram ........................................................................... 195 Figure 19.2. PCA Counter/Timer Block Diagram ................................................... 196 Figure 19.3. PCA Interrupt Block Diagram ............................................................ 197 Figure 19.4. PCA Capture Mode Diagram ............................................................. 198 Figure 19.5. PCA Software Timer Mode Diagram ................................................. 199 Figure 19.6. PCA High-Speed Output Mode Diagram ........................................... 200 Figure 19.7. PCA Frequency Output Mode ........................................................... 201 Figure 19.8. PCA 8-Bit PWM Mode Diagram ........................................................ 202 Figure 19.9. PCA 16-Bit PWM Mode ..................................................................... 203 Figure 19.10. PCA Module 2 with Watchdog Timer Enabled ................................ 204 Figure 20.1. Device Package—TSSOP 20 ............................................................ 210 Figure 20.2. Device Package—QFN 20 ................................................................ 210 Figure 20.3. Device Package—DFN 10 ................................................................ 211 Figure 21.1. Typical C2 Pin Sharing ...................................................................... 216 8 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA List of Tables Table 1.1. Product Selection Guide (Recommended for New Designs) .................. 14 Table 1.2. Product Selection Guide (Not Recommended for New Designs) ........... 15 Table 1.3. Operating Modes Summary .................................................................... 21 Table 2.1. Absolute Maximum Ratings .................................................................... 25 Table 2.2. Global DC Electrical Characteristics ....................................................... 26 Table 2.3. ADC0 Electrical Characteristics .............................................................. 28 Table 2.4. Temperature Sensor Electrical Characteristics ...................................... 29 Table 2.5. Voltage Reference Electrical Characteristics ......................................... 29 Table 2.6. Voltage Regulator Electrical Specifications ............................................ 30 Table 2.7. Comparator Electrical Characteristics .................................................... 31 Table 2.8. Reset Electrical Characteristics .............................................................. 32 Table 2.9. Flash Electrical Characteristics .............................................................. 33 Table 2.10. Port I/O DC Electrical Characteristics ................................................... 33 Table 2.11. Internal Oscillator Electrical Characteristics ......................................... 34 Table 3.1. Pin Definitions for the C8051F52x and C8051F52xA (DFN 10) ............. 36 Table 3.2. DFN-10 Package Diagram Dimensions .................................................. 38 Table 3.3. DFN-10 Landing Diagram Dimensions ................................................... 39 Table 3.4. Pin Definitions for the C8051F53x and C805153xA (TSSOP 20) .......... 40 Table 3.5. TSSOP-20 Package Diagram Dimensions ............................................. 43 Table 3.6. TSSOP-20 Landing Diagram Dimensions .............................................. 44 Table 3.7. Pin Definitions for the C8051F53x and C805153xA (QFN 20) ............... 46 Table 3.8. QFN-20 Package Diagram Dimensions ................................................. 49 Table 3.9. QFN-20 Landing Diagram Dimensions ................................................... 51 Table 8.1. CIP-51 Instruction Set Summary ............................................................ 83 Table 9.1. Special Function Register (SFR) Memory Map ...................................... 94 Table 9.2. Special Function Registers ..................................................................... 95 Table 10.1. Interrupt Summary ................................................................................ 99 Table 12.1. Flash Security Summary .................................................................... 118 Table 15.1. Timer Settings for Standard Baud Rates Using the Internal Oscillator ............................................................... 150 Table 16.1. SPI Slave Timing Parameters ............................................................ 163 Table 17.1. Baud-Rate Calculation Variable Ranges ............................................ 166 Table 17.2. Manual Baud Rate Parameters Examples ......................................... 167 Table 17.3. Autobaud Parameters Examples ........................................................ 168 Table 17.4. LIN Registers* (Indirectly Addressable) .............................................. 174 Table 19.1. PCA Timebase Input Options ............................................................. 196 Table 19.2. PCA0CPM Register Settings for PCA Capture/Compare Modules .... 197 Table 19.3. Watchdog Timer Timeout Intervals1 ................................................... 205 Rev. 1.4 9 C8051F52x/F52xA/F53x/F53xA List of Registers SFR Definition 4.4. ADC0MX: ADC0 Channel Select ................................................... 64 SFR Definition 4.5. ADC0CF: ADC0 Configuration ..................................................... 65 SFR Definition 4.6. ADC0H: ADC0 Data Word MSB .................................................... 66 SFR Definition 4.7. ADC0L: ADC0 Data Word LSB ..................................................... 66 SFR Definition 4.8. ADC0CN: ADC0 Control ............................................................... 67 SFR Definition 4.9. ADC0TK: ADC0 Tracking Mode Select ........................................ 68 SFR Definition 4.10. ADC0GTH: ADC0 Greater-Than Data High Byte ........................ 69 SFR Definition 4.11. ADC0GTL: ADC0 Greater-Than Data Low Byte ......................... 69 SFR Definition 4.12. ADC0LTH: ADC0 Less-Than Data High Byte .............................. 70 SFR Definition 4.13. ADC0LTL: ADC0 Less-Than Data Low Byte ............................... 70 SFR Definition 5.1. REF0CN: Reference Control ......................................................... 73 SFR Definition 6.1. REG0CN: Regulator Control .......................................................... 75 SFR Definition 7.1. CPT0CN: Comparator0 Control ..................................................... 78 SFR Definition 7.2. CPT0MX: Comparator0 MUX Selection ........................................ 79 SFR Definition 7.3. CPT0MD: Comparator0 Mode Selection ....................................... 80 SFR Definition 8.1. SP: Stack Pointer ........................................................................... 87 SFR Definition 8.2. DPL: Data Pointer Low Byte .......................................................... 87 SFR Definition 8.3. DPH: Data Pointer High Byte ......................................................... 87 SFR Definition 8.4. PSW: Program Status Word .......................................................... 88 SFR Definition 8.5. ACC: Accumulator ......................................................................... 89 SFR Definition 8.6. B: B Register .................................................................................. 89 SFR Definition 8.7. PCON: Power Control .................................................................... 91 SFR Definition 10.1. IE: Interrupt Enable .................................................................... 100 SFR Definition 10.2. IP: Interrupt Priority .................................................................... 101 SFR Definition 10.3. EIE1: Extended Interrupt Enable 1 ............................................ 102 SFR Definition 10.4. EIP1: Extended Interrupt Priority 1 ............................................ 103 SFR Definition 10.5. IT01CF: INT0/INT1 Configuration .............................................. 105 SFR Definition 11.1. VDDMON: VDD Monitor Control ................................................ 109 SFR Definition 11.2. RSTSRC: Reset Source ............................................................ 112 SFR Definition 12.1. PSCTL: Program Store R/W Control ......................................... 119 SFR Definition 12.2. FLKEY: Flash Lock and Key ...................................................... 119 SFR Definition 13.1. XBR0: Port I/O Crossbar Register 0 .......................................... 127 SFR Definition 13.2. XBR1: Port I/O Crossbar Register 1 .......................................... 128 SFR Definition 13.3. P0: Port0 .................................................................................... 129 SFR Definition 13.4. P0MDIN: Port0 Input Mode ........................................................ 129 SFR Definition 13.5. P0MDOUT: Port0 Output Mode ................................................. 130 SFR Definition 13.6. P0SKIP: Port0 Skip .................................................................... 130 SFR Definition 13.7. P0MAT: Port0 Match ................................................................. 131 SFR Definition 13.8. P0MASK: Port0 Mask ................................................................ 131 SFR Definition 13.9. P1: Port1 .................................................................................... 132 SFR Definition 13.10. P1MDIN: Port1 Input Mode ...................................................... 132 SFR Definition 13.11. P1MDOUT: Port1 Output Mode ............................................... 133 SFR Definition 13.12. P1SKIP: Port1 Skip .................................................................. 133 Rev. 1.4 10 C8051F52x/F52xA/F53x/F53xA SFR Definition 13.13. P0SKIP: Port0 Skip .................................................................. 134 SFR Definition 13.14. P1MAT: Port1 Match ............................................................... 134 SFR Definition 13.15. P1MASK: Port1 Mask .............................................................. 134 SFR Definition 14.1. OSCICN: Internal Oscillator Control .......................................... 137 SFR Definition 14.2. OSCICL: Internal Oscillator Calibration ..................................... 138 SFR Definition 14.3. OSCIFIN: Internal Fine Oscillator Calibration ............................ 138 SFR Definition 14.4. OSCXCN: External Oscillator Control ........................................ 142 SFR Definition 14.5. CLKSEL: Clock Select ............................................................... 143 SFR Definition 15.1. SCON0: Serial Port 0 Control .................................................... 149 SFR Definition 15.2. SBUF0: Serial (UART0) Port Data Buffer .................................. 150 SFR Definition 16.1. SPI0CFG: SPI0 Configuration ................................................... 157 SFR Definition 16.2. SPI0CN: SPI0 Control ............................................................... 158 SFR Definition 16.3. SPI0CKR: SPI0 Clock Rate ....................................................... 159 SFR Definition 16.4. SPI0DAT: SPI0 Data ................................................................. 160 SFR Definition 17.1. LINADDR: Indirect Address Register ......................................... 172 SFR Definition 17.2. LINDATA: LIN Data Register ..................................................... 172 SFR Definition 17.3. LINCF Control Mode Register ................................................... 173 SFR Definition 17.4. LIN0DT1: LIN0 Data Byte 1 ....................................................... 174 SFR Definition 17.5. LIN0DT2: LIN0 Data Byte 2 ....................................................... 175 SFR Definition 17.6. LIN0DT3: LIN0 Data Byte 3 ....................................................... 175 SFR Definition 17.7. LIN0DT4: LIN0 Data Byte 4 ....................................................... 175 SFR Definition 17.8. LIN0DT5: LIN0 Data Byte 5 ....................................................... 176 SFR Definition 17.9. LIN0DT6: LIN0 Data Byte 6 ....................................................... 176 SFR Definition 17.10. LIN0DT7: LIN0 Data Byte 7 ..................................................... 176 SFR Definition 17.11. LIN0DT8: LIN0 Data Byte 8 ..................................................... 176 SFR Definition 17.12. LIN0CTRL: LIN0 Control Register ........................................... 177 SFR Definition 17.13. LIN0ST: LIN0 STATUS Register ............................................. 178 SFR Definition 17.14. LIN0ERR: LIN0 ERROR Register ............................................ 179 SFR Definition 17.15. LIN0SIZE: LIN0 Message Size Register .................................. 180 SFR Definition 17.16. LIN0DIV: LIN0 Divider Register ............................................... 180 SFR Definition 17.17. LIN0MUL: LIN0 Multiplier Register .......................................... 181 SFR Definition 17.18. LIN0ID: LIN0 ID Register ......................................................... 181 SFR Definition 18.1. TCON: Timer Control ................................................................. 186 SFR Definition 18.2. TMOD: Timer Mode ................................................................... 187 SFR Definition 18.3. CKCON: Clock Control .............................................................. 188 SFR Definition 18.4. TL0: Timer 0 Low Byte ............................................................... 189 SFR Definition 18.5. TL1: Timer 1 Low Byte ............................................................... 189 SFR Definition 18.6. TH0: Timer 0 High Byte ............................................................. 189 SFR Definition 18.7. TH1: Timer 1 High Byte ............................................................. 189 SFR Definition 18.8. TMR2CN: Timer 2 Control ......................................................... 193 SFR Definition 18.9. TMR2RLL: Timer 2 Reload Register Low Byte .......................... 194 SFR Definition 18.10. TMR2RLH: Timer 2 Reload Register High Byte ...................... 194 SFR Definition 18.11. TMR2L: Timer 2 Low Byte ....................................................... 194 SFR Definition 18.12. TMR2H Timer 2 High Byte ....................................................... 194 SFR Definition 19.1. PCA0CN: PCA Control .............................................................. 206 11 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 19.2. PCA0MD: PCA Mode ................................................................ 207 SFR Definition 19.3. PCA0CPMn: PCA Capture/Compare Mode .............................. 208 SFR Definition 19.4. PCA0L: PCA Counter/Timer Low Byte ...................................... 209 SFR Definition 19.5. PCA0H: PCA Counter/Timer High Byte ..................................... 209 SFR Definition 19.6. PCA0CPLn: PCA Capture Module Low Byte ............................. 209 SFR Definition 19.7. PCA0CPHn: PCA Capture Module High Byte ........................... 209 C2 Register Definition 21.1. C2ADD: C2 Address ...................................................... 214 C2 Register Definition 21.2. DEVICEID: C2 Device ID ............................................... 214 C2 Register Definition 21.3. REVID: C2 Revision ID .................................................. 215 C2 Register Definition 21.4. FPCTL: C2 Flash Programming Control ........................ 215 C2 Register Definition 21.5. FPDAT: C2 Flash Programming Data ............................ 215 Rev. 1.4 12 C8051F52x/F52xA/F53x/F53xA 1. System Overview The C8051F52x/F52xA/F53x/F53xA family of devices are fully integrated, low power, mixed-signal systemon-a-chip MCUs. Highlighted features are listed below. Refer to Table 1.1 for specific product feature selection.            High-speed pipelined 8051-compatible microcontroller core (up to 25 MIPS) In-system, full-speed, non-intrusive debug interface (on-chip) True 12-bit 200 ksps ADC with analog multiplexer and up to 16 analog inputs Precision programmable 24.5 MHz internal oscillator that is within ±0.5% across the temperature range and for VDD voltages greater than or equal to the on-chip voltage regulator minimum output at the low setting. The oscillator is within +1.0% for VDD voltages below this minimum output setting. Up to 7680 bytes of on-chip Flash memory 256 bytes of on-chip RAM Enhanced UART, and SPI serial interfaces implemented in hardware LIN 2.1 peripheral (fully backwards compatible, master and slave modes) Three general-purpose 16-bit timers Programmable Counter/Timer Array (PCA) with three capture/compare modules and Watchdog Timer function On-chip Power-On Reset, VDD Monitor, and Temperature Sensor  On-chip Voltage Comparator  Up to 16 Port I/O With on-chip Power-On Reset, VDD monitor, Watchdog Timer, and clock oscillator, the C8051F52x/F52xA/F53x/F53xA devices are truly standalone system-on-a-chip solutions. The Flash memory is byte writable and can be reprogrammed in-circuit, providing non-volatile data storage, and also allowing field upgrades of the 8051 firmware. User software has complete control of all peripherals, and may individually shut down any or all peripherals for power savings. The on-chip Silicon Laboratories 2-Wire (C2) Development Interface allows non-intrusive (uses no on-chip resources), full speed, in-circuit debugging using the production MCU installed in the final application. This debug logic supports inspection and modification of memory and registers, setting breakpoints, single stepping, run and halt commands. All analog and digital peripherals are fully functional while debugging using C2. The two C2 interface pins can be shared with user functions, allowing in-system programming and debugging without occupying package pins. Each device is specified for 2.0 to 5.25 V operation (supply voltage can be up to 5.25 V using on-chip regulator) over the automotive temperature range (–40 to +125 °C). The F52x/F52xA is available in the DFN10 (3 x 3 mm) package. The F53x/F53xA is available in the QFN20 (4 x 4 mm) or the TSSOP20 package. Rev. 1.4 13 C8051F52x/F52xA/F53x/F53xA 1.1. Ordering Information The following features are common to all devices in this family:            25 MHz system clock and 25 MIPS throughput (peak) 256 bytes of internal RAM Enhanced SPI peripheral Enhanced UART peripheral Three Timers Three Programmable Counter Array channels Internal 24.5 MHz oscillator Internal Voltage Regulator 12-bit, 200 ksps ADC Internal Voltage Reference and Temperature Sensor One Analog Comparator Table 1.1 shows the features that differentiate the devices in this family.  DFN-10 C8051F534-C-IM 4 16 — QFN-20 C8051F521-C-IM 8 6 — DFN-10 C8051F536-C-IM 2 16  QFN-20 C8051F523-C-IM 4 6  DFN-10 C8051F537-C-IM 2 16 — QFN-20 TSSOP-20 Package 6 LIN 8 Port I/Os Flash Memory (kB) LIN Ordering Part Number Port I/Os C8051F520-C-IM Package Flash Memory (kB) Ordering Part Number Table 1.1. Product Selection Guide (Recommended for New Designs) C8051F524-C-IM 4 6 — DFN-10 C8051F530-C-IT 8 16  C8051F526-C-IM 2 6  DFN-10 C8051F531-C-IT 8 16 — TSSOP-20 C8051F527-C-IM 2 6 — DFN-10 C8051F533-C-IT 4 16  C8051F530-C-IM 8 16  QFN-20 C8051F534-C-IT 4 16 — TSSOP-20 TSSOP-20 C8051F531-C-IM 8 16 — QFN-20 C8051F536-C-IT 2 16  C8051F533-C-IM 4 16  QFN-20 C8051F537-C-IT 2 16 — TSSOP-20 TSSOP-20 All devices in Table 1.1 are also available in an automotive version. For the automotive version, the -I in the ordering part number is replaced with -A. For example, the automotive version of the C8051F520-C-IM is the C8051F520-C-AM. The -AM and -AT devices receive full automotive quality production status, including AEC-Q100 qualification (fault coverage report available upon request), registration with International Material Data System (IMDS) and Part Production Approval Process (PPAP) documentation. PPAP documentation is available at www.silabs.com with a registered NDA and approved user account. The -AM and -AT devices enable high volume automotive OEM applications with their enhanced testing and processing. Please contact Silicon Labs sales for more information regarding -AM and -AT devices for your automotive project. 14 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA  DFN-10 C8051F534-IM 4 C8051F534A-IM 16 — QFN-20 C8051F521-IM C8051F521A-IM 8 6 — DFN-10 C8051F536-IM 2 C8051F536A-IM 16  QFN-20 C8051F523-IM C8051F523A-IM 4 6  DFN-10 C8051F537-IM 2 C8051F537A-IM 16 — QFN-20 C8051F524-IM C8051F524A-IM 4 6 — DFN-10 C8051F530-IT C8051F530A-IT 8 16  TSSOP-20 C8051F526-IM C8051F526A-IM 2 6  DFN-10 C8051F531-IT C8051F531A-IT 8 16 — TSSOP-20 C8051F527-IM C8051F527A-IM 2 6 — DFN-10 C8051F533-IT C8051F533A-IT 4 16  C8051F530-IM C8051F530A-IM 8 16  QFN-20 C8051F534-IT C8051F534A-IT 4 16 — TSSOP-20 C8051F531-IM C8051F531A-IM 8 16 — QFN-20 C8051F536-IT C8051F536A-IT 2 16  C8051F533-IM C8051F533A-IM 4 16  QFN-20 C8051F537-IT C8051F537A-IT 2 16 — TSSOP-20 Package 6 LIN 8 Port I/Os Flash Memory (kB) LIN Ordering Part Number Port I/Os C8051F520-IM C8051F520A-IM Package Flash Memory (kB) Ordering Part Number Table 1.2. Product Selection Guide (Not Recommended for New Designs) TSSOP-20 TSSOP-20 The part numbers in Table 1.2 are not recommended for new designs. Instead, select the corresponding part number from Table 1.1 (silicon revision C) for your design. In Table 1.2, the part numbers in the format similar to C8051F520-IM are silicon revision A devices. The part numbers in the format similar to C8051F520A-IM are silicon revision B devices. Rev. 1.4 15 C8051F52x/F52xA/F53x/F53xA Power On Reset Reset C2CK/RST Port I/O Configuration CIP-51 8051 Controller Core Digital Peripherals up to 8k Byte Flash Program Memory Debug / Programming Hardware VREGIN Port 0 Drivers P0.0/VREF P0.1 P0.2 P0.3 P0.4/TX P0.5/RX P0.6/C2D P0.7/XTAL1 Port 1 Drivers P1.0/XTAL2 P1.1 P1.2/CNVSTR P1.3 P1.4 P1.5 P1.6 P1.7 UART0 Timers 0, 1, 2, 3 256 Byte SRAM Priority Crossbar Decoder PCA/ WDT C2D LIN 2.1 VREGIN Voltage Regulator (LDO) SPI Crossbar Control SFR Bus VDD GND Analog Peripherals Voltage Reference System Clock Setup VDD XTAL1 XTAL2 VREF VREF External Oscillator 12-bit 200ksps ADC Internal Oscillator VDD VREF A M U X Temp Sensor GND CP0, CP0A + - Comparator Figure 1.1. C8051F53xA/F53x-C Block Diagram Power On Reset Reset C2CK/RST Port I/O Configuration CIP-51 8051 Controller Core Digital Peripherals up to 8k Byte Flash Program Memory Debug / Programming Hardware VREGIN UART0 Timers 0, 1, 2, 3 256 Byte SRAM Priority Crossbar Decoder PCA/ WDT C2D Port 0 Drivers LIN 2.1 VREGIN Voltage Regulator (LDO) SPI Crossbar Control SFR Bus VDD GND Analog Peripherals Voltage Reference System Clock Setup XTAL1 XTAL2 VDD VREF VREF External Oscillator Internal Oscillator A M U X 12-bit 200ksps ADC VDD VREF Temp Sensor GND CP0, CP0A + - Comparator Figure 1.2. C8051F52xA/F52x-C Block Diagram 16 Rev. 1.4 P0.0/VREF P0.1/C2D P0.2/XTAL1 P0.3/XTAL2 P0.4/TX P0.5/RX/ CNVSTR C8051F52x/F52xA/F53x/F53xA Power On Reset Reset C2CK/RST Port I/O Configuration CIP-51 8051 Controller Core Digital Peripherals up to 8k Byte Flash Program Memory Debug / Programming Hardware VREGIN Port 0 Drivers P0.0/VREF P0.1 P0.2 P0.3/TX P0.4/RX P0.5 P0.6/C2D P0.7/XTAL1 Port 1 Drivers P1.0/XTAL2 P1.1 P1.2/CNVSTR P1.3 P1.4 P1.5 P1.6 P1.7 UART0 Timers 0, 1, 2, 3 256 Byte SRAM Priority Crossbar Decoder PCA/ WDT C2D LIN 2.1 VREGIN Voltage Regulator (LDO) SPI Crossbar Control SFR Bus VDD GND Analog Peripherals Voltage Reference System Clock Setup VDD XTAL1 XTAL2 VREF VREF External Oscillator 12-bit 200ksps ADC Internal Oscillator VDD VREF A M U X Temp Sensor GND CP0, CP0A + - Comparator Figure 1.3. C8051F53x Block Diagram (Silicon Revision A) Power On Reset Reset C2CK/RST Port I/O Configuration CIP-51 8051 Controller Core Digital Peripherals up to 8k Byte Flash Program Memory Debug / Programming Hardware VREGIN UART0 Timers 0, 1, 2, 3 256 Byte SRAM Priority Crossbar Decoder PCA/ WDT C2D Port 0 Drivers P0.0/VREF P0.1/C2D P0.2/XTAL1 P0.3/XTAL2/TX P0.4/RX P0.5/CNVSTR LIN 2.1 VREGIN Voltage Regulator (LDO) SPI Crossbar Control SFR Bus VDD GND Analog Peripherals Voltage Reference System Clock Setup XTAL1 XTAL2 VDD VREF VREF External Oscillator Internal Oscillator A M U X 12-bit 200ksps ADC VDD VREF Temp Sensor GND CP0, CP0A + - Comparator Figure 1.4. C8051F52x Block Diagram (Silicon Revision A) Rev. 1.4 17 C8051F52x/F52xA/F53x/F53xA 1.2. CIP-51™ Microcontroller 1.2.1. Fully 8051 Compatible Instruction Set The C8051F52x/F52xA/F53x/F53xA devices use Silicon Laboratories’ proprietary CIP-51 microcontroller core. The CIP-51 is fully compatible with the MCS-51™ instruction set. Standard 803x/805x assemblers and compilers can be used to develop software. The C8051F52x/F52xA/F53x/F53xA family has a superset of all the peripherals included with a standard 8052. 1.2.2. Improved Throughput The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system clock cycles to execute, and usually have a maximum system clock of 12-to-24 MHz. By contrast, the CIP51 core executes 70% of its instructions in one or two system clock cycles, with no instructions taking more than eight system clock cycles. With the CIP-51's system clock running at 25 MHz, it has a peak throughput of 25 MIPS. The CIP-51 has a total of 109 instructions. The table below shows the total number of instructions that require each execution time. Clocks to Execute 1 2 2/3 3 3/4 4 4/5 5 8 Number of Instructions 26 50 5 14 7 3 1 2 1 1.2.3. Additional Features The C8051F52x/F52xA/F53x/F53xA family includes several key enhancements to the CIP-51 core and peripherals to improve performance and ease of use in end applications. An extended interrupt handler allows the numerous analog and digital peripherals to operate independently of the controller core and interrupt the controller only when necessary. By requiring less intervention from the microcontroller core, an interrupt-driven system is more efficient and allows for easier implementation of multi-tasking, real-time systems. Eight reset sources are available: power-on reset circuitry (POR), an on-chip VDD monitor, a Watchdog Timer, a Missing Clock Detector, a voltage level detection from Comparator, a forced software reset, an external reset pin, and an illegal Flash access protection circuit. Each reset source except for the POR, Reset Input Pin, or Flash error may be disabled by the user in software. The WDT may be permanently enabled in software after a power-on reset during MCU initialization. The internal oscillator is factory calibrated to 24.5 MHz ±0.5% across the entire operating temperature and voltage range. An external oscillator drive circuit is also included, allowing an external crystal, ceramic resonator, capacitor, RC, or CMOS clock source to generate the system clock. 1.2.4. On-Chip Debug Circuitry The C8051F52x/F52xA/F53x/F53xA devices include on-chip Silicon Laboratories 2-Wire (C2) debug circuitry that provides non-intrusive, full speed, in-circuit debugging of the production part installed in the end application. Silicon Laboratories’ debugging system supports inspection and modification of memory and registers, breakpoints, and single stepping. No additional target RAM, program memory, timers, or communications channels are required. All the digital and analog peripherals are functional and work correctly while debugging. All the peripherals (except for the ADC) are stalled when the MCU is halted, during single stepping, or at a breakpoint in order to keep them synchronized. The C8051F530DK development kit provides all the hardware and software necessary to develop application code and perform in-circuit debugging with the C8051F52x/F52xA/F53x/F53xA MCUs. The kit 18 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA includes software with a developer's studio and debugger, a USB debug adapter, a target application board with the associated MCU installed, and the required cables and wall-mount power supply. The development kit requires a computer with Windows installed. As shown in Figure 1.5, the PC is connected to the USB debug adapter. A six-inch ribbon cable connects the USB debug adapter to the user's application board, picking up the two C2 pins and GND. The Silicon Laboratories IDE interface is a vastly superior developing and debugging configuration, compared to standard MCU emulators that use on-board "ICE Chips" and require the MCU in the application board to be socketed. Silicon Laboratories’ debug paradigm increases ease of use and preserves the performance of the precision analog peripherals. Target Board J8 D2 J6 PC D1 P1.4_B J14 C8051F530A TB U1 HDR3 P5 DEBUG_B T1 PWR U2 J13 U3 T2 SILICON LABORATORIES “B” Side HDR2 Reset_A P1 J4 J3 J5 “A” Side P1.6_B P1.7_B DEBUG_A P0.0_B Run Stop Silicon Laboratories USB DEBUG ADAPTER Power USB Cable P1.4_A HDR4 USB Debug Adapter HDR1 Reset_B AC/DC Adapter Figure 1.5. Development/In-System Debug Diagram Rev. 1.4 19 C8051F52x/F52xA/F53x/F53xA 1.3. On-Chip Memory The CIP-51 has a standard 8051 program and data address configuration. It includes 256 bytes of data RAM, with the upper 128 bytes dual-mapped. Indirect addressing accesses the upper 128 bytes of general purpose RAM, and direct addressing accesses the 128 byte SFR address space. The lower 128 bytes of RAM are accessible via direct and indirect addressing. The first 32 bytes are addressable as four banks of general purpose registers, and the next 16 bytes can be byte addressable or bit addressable. Program memory consists of 7680 bytes (’F520/0A/1/1A and ’F530/0A/1/1A), 4 kB (’F523/3A/4/4A and C8051F53x/53xA), or 2 kB (’F526/6A/7/7A and ’F536/6A/7/7A) of Flash. This memory is byte writable and erased in 512-byte sectors, and requires no special off-chip programming voltage. PROGRAM/DATA MEMORY (Flash) 'F520/0A/1/1A and 'F530/0A/1/1A 0x1E00 0x1DFF 0xFF RESERVED 8 kB Flash (In-System Programmable in 512 Byte Sectors) 0x0000 'F523/3A/4/4A and 'F533/3A/4/4A 0x1000 0x0FFF DATA MEMORY (RAM) INTERNAL DATA ADDRESS SPACE 0x80 0x7F Upper 128 RAM (Indirect Addressing Only) (Direct and Indirect Addressing) 0x30 0x2F 0x20 0x1F 0x00 Bit Addressable General Purpose Registers RESERVED 4 kB Flash 0x0000 (In-System Programmable in 512 Byte Sectors) 'F526/6A/7/7A and 'F536/6A/7/7A 0x0800 0x07FF RESERVED 2 kB Flash (In-System Programmable in 512 Byte Sectors) 0x0000 Figure 1.6. Memory Map 20 Rev. 1.4 Special Function Register's (Direct Addressing Only) Lower 128 RAM (Direct and Indirect Addressing) C8051F52x/F52xA/F53x/F53xA 1.4. Operating Modes The C8051F52x/F52xA/F53x/F53xA devices have four operating modes: Active (Normal), Idle, Suspend, and Stop. Active mode occurs during normal operation when the oscillator and peripherals are active. Idle mode halts the CPU while leaving the peripherals and internal clocks active. In Suspend and Stop mode, the CPU is halted, all interrupts and timers are inactive, and the internal oscillator is stopped. The various operating modes are described in Table 1.3 below: Table 1.3. Operating Modes Summary Properties Active  SYSCLK active CPU active (accessing Flash)  Peripherals active or inactive depending on user settings Power Consumption Full How Entered? — How Exited? —  Idle  Less than Full IDLE (PCON.0) Any enabled interrupt or device reset Suspend  Low SUSPEND (OSCICN.5) Port 0 event match Port 1 event match Comparator 0 enabled and output is logic 0 Stop  Very low STOP (PCON.1) Device Reset SYSCLK active  CPU inactive (not accessing Flash)  Peripherals active or inactive depending on user settings Internal oscillator inactive  If SYSCLK is derived from the internal oscillator, the peripherals and the CIP-51 will be stopped SYSCLK inactive CPU inactive (not accessing Flash)  Digital peripherals inactive; analog peripherals active or inactive depending on user settings  See Section “8.3. Power Management Modes” on page 89 for Idle and Stop mode details. See Section “14.1.1. Internal Oscillator Suspend Mode” on page 136 for more information on Suspend mode. Rev. 1.4 21 C8051F52x/F52xA/F53x/F53xA 1.5. 12-Bit Analog to Digital Converter The C8051F52x/F52xA/F53x/F53xA devices include an on-chip 12-bit SAR ADC with a maximum throughput of 200 ksps. The ADC system includes a configurable analog multiplexer that selects the positive ADC input, which is measured with respect to GND. Ports 0 and 1 are available as ADC inputs; additionally, the ADC includes an innovative programmable gain stage which allows the ADC to sample inputs sources greater than the VREF voltage. The on-chip Temperature Sensor output and the core supply voltage (VDD) are also available as ADC inputs. User firmware may shut down the ADC or use it in Burst Mode to save power. Conversions can be initiated in four ways: a software command, an overflow of Timer 1, an overflow of Timer 2, or an external convert start signal. This flexibility allows the start of conversion to be triggered by software events, a periodic signal (timer overflows), or external HW signals. Conversion completions are indicated by a status bit and an interrupt (if enabled) and occur after 1, 4, 8, or 16 samples have been accumulated by a hardware accumulator. The resulting 12-bit to 16-bit data word is latched into the ADC data SFRs upon completion of a conversion. When the system clock is slow, Burst Mode allows ADC0 to automatically wake from a low power shutdown state, acquire and accumulate samples, then re-enter the low power shutdown state without CPU intervention. Window compare registers for the ADC data can be configured to interrupt the controller when ADC data is either within or outside of a specified range. The ADC can monitor a key voltage continuously in background mode, but not interrupt the controller unless the converted data is within/outside the specified range. Analog Multiplexer Configuration, Control, and Data Registers P0.0 P0.6* P0.7* P1.0* P1.7* * Available on ‘F53x/ ’F53xA devices Burst Mode Logic Timer 2 Overflow 19-to-1 AMUX 12-Bit SAR Selectable Gain VDD GND End of Conversion Interrupt Figure 1.7. 12-Bit ADC Block Diagram 22 Timer 1 Overflow CNVSTR Rising Edge ADC Temp Sensor AD0BUSY (W) Start Conversion Rev. 1.4 ADC Data Registers 16 Accumulator Window Compare Logic Window Compare Interrupt C8051F52x/F52xA/F53x/F53xA 1.6. Programmable Comparator C8051F52x/F52xA/F53x/F53xA devices include a software-configurable voltage comparator with an input multiplexer. The comparator offers programmable response time and hysteresis and an output that is optionally available at the Port pins: a synchronous “latched” output (CP0). The comparator interrupt may be generated on rising, falling, or both edges. When in IDLE or SUSPEND mode, these interrupts may be used as a “wake-up” source for the processor. The Comparator may also be configured as a reset source. A block diagram of the comparator is shown in Figure 1.8. VDD Port I/O Pins Multiplexer Interrupt Logic + D - SET CLR Q Q D SET CLR Q CP0 (synchronous output) Q (SYNCHRONIZER) CP0A (asynchronous output) GND Reset Decision Tree Figure 1.8. Comparator Block Diagram 1.7. Voltage Regulator C8051F52x/F52xA/F53x/F53xA devices include an on-chip low dropout voltage regulator (REG0). The input to REG0 at the VREGIN pin can be as high as 5.25 V. The output can be selected by software to 2.1 or 2.6 V. When enabled, the output of REG0 powers the device and drives the VDD pin. The voltage regulator can be used to power external devices connected to VDD. 1.8. Serial Port The C8051F52x/F52xA/F53x/F53xA family includes a full-duplex UART with enhanced baud rate configuration, and an Enhanced SPI interface. Each of the serial buses is fully implemented in hardware and makes extensive use of the CIP-51's interrupts, thus requiring very little CPU intervention. Rev. 1.4 23 C8051F52x/F52xA/F53x/F53xA 1.9. Port Input/Output C8051F52x/F52xA/F53x/F53xA devices include up to 16 I/O pins. Port pins are organized as two bytewide ports. The port pins behave like typical 8051 ports with a few enhancements. Each port pin can be configured as a digital or analog I/O pin. Pins selected as digital I/O can be configured for push-pull or open-drain operation. The “weak pullups” that are fixed on typical 8051 devices may be globally disabled to save power. The Digital Crossbar allows mapping of internal digital system resources to port I/O pins. On-chip counter/timers, serial buses, hardware interrupts, and other digital signals can be configured to appear on the port pins using the Crossbar control registers. This allows the user to select the exact mix of generalpurpose port I/O, digital, and analog resources needed for the application. P0MASK, P0MATCH P1MASK, P1MATCH Registers XBR0, XBR1, PnSKIP Registers PnMDOUT, PnMDIN Registers Priority Decoder Highest Priority 2 UART 4 (Internal Digital Signals) SPI 2 LIN CP0 Outputs 8 7 T0, T1 (Port Latches) P0 I/O Cells P1 I/O Cells 2 8 P0 8 2 SYSCLK PCA Lowest Priority Digital Crossbar *Available in 'F53x/'F53xA devices (P0.0-P0.7) 8 P1 (P1.0-P1.7*) Figure 1.9. Port I/O Functional Block Diagram 24 Rev. 1.4 P0.0 P0.7 P1.0* P1.7* C8051F52x/F52xA/F53x/F53xA 2. Electrical Characteristics 2.1. Absolute Maximum Ratings Table 2.1. Absolute Maximum Ratings Parameter Conditions Min Typ Max Units Ambient temperature under Bias –55 — 135 °C Storage Temperature –65 — 150 °C Voltage on VREGIN with Respect to GND –0.3 — 5.5 V Voltage on VDD with Respect to GND –0.3 — 2.8 V Voltage on XTAL1 with Respect to GND –0.3 — VREGIN + 0.3 V Voltage on XTAL2 with Respect to GND –0.3 — VREGIN + 0.3 V Voltage on any Port I/O Pin or RST with Respect to GND –0.3 — VREGIN + 0.3 V Maximum Output Current Sunk by any Port Pin — — 100 mA Maximum Output Current Sourced by any Port Pin — — 100 mA Maximum Total Current through VREGIN, and GND — — 500 mA Note: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the devices at those or any other conditions above those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. Rev. 1.4 25 C8051F52x/F52xA/F53x/F53xA 2.2. Electrical Characteristics Table 2.2. Global DC Electrical Characteristics –40 to +125 °C, 25 MHz System Clock unless otherwise specified. Typical values are given at 25 °C Parameter Min Typ Max Units Output Current < 1 mA C8051F52x/53x C8051F52xA/53xA C8051F52x-C/53x-C 2.7 1.81 2.01 — — — 5.25 5.25 5.25 V V V C8051F52x/53x C8051F52xA/53xA C8051F52x-C/53x-C 2.0 1.8 2.0 — — — 2.7 2.7 2.75 V V V Core Supply RAM Data Retention Voltage — 1.5 — SYSCLK (System Clock)2 0 — 25 MHz –40 — +125 °C Supply Input Voltage (VREGIN)1 Digital Supply Voltage (VDD) Conditions Specified Operating Temperature Range V Digital Supply Current—CPU Active (Normal Mode, fetching instructions from Flash) IDD3,4 IDD Frequency Sensitivity3,5 VDD = 2.1 V: Clock = 32 kHz Clock = 200 kHz Clock = 1 MHz Clock = 25 MHz VDD = 2.6 V: Clock = 32 kHz Clock = 200 kHz Clock = 1 MHz Clock = 25 MHz T = 25 °C: VDD = 2.1 V, F < 12 MHz VDD = 2.1 V, F > 12 MHz VDD = 2.6 V, F < 12 MHz VDD = 2.6 V, F > 12 MHz — — — — 13 60 0.28 5.1 — — — 9 µA µA mA mA — — — — 22 105 0.5 7.3 — — — 13 µA µA mA mA — — — — 0.276 0.140 0.424 0.184 — — — — mA/MHz mA/MHz mA/MHz mA/MHz Notes: 1. 2. 3. 4. 5. For more information on VREGIN characteristics, see Table 2.6 on page 30. SYSCLK must be at least 32 kHz to enable debugging. Based on device characterization data; Not production tested. Does not include internal oscillator or internal regulator supply current. IDD can be estimated for frequencies 12 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by the frequency sensitivity number. For example: VDD = 2.6 V; F= 20 MHz, IDD = 7.3 mA – (25 MHz – 20 MHz) x 0.184 mA/MHz = 6.38 mA. 6. Idle IDD can be estimated for frequencies 1 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by the frequency sensitivity number. For example: VDD = 2.6 V; F= 5 MHz, Idle IDD = 3 mA – (25 MHz– 5 MHz) x 118 µA/MHz = 0.64 mA. 26 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 2.2. Global DC Electrical Characteristics –40 to +125 °C, 25 MHz System Clock unless otherwise specified. Typical values are given at 25 °C Parameter Conditions Min Typ Max Units Digital Supply Current—CPU Inactive (Idle Mode, not fetching instructions from Flash) Idle IDD3,4 Idle IDD Frequency Sensitivity3,6 Digital Supply Current3 (Stop or Suspend Mode) VDD = 2.1 V: Clock = 32 kHz Clock = 200 kHz Clock = 1 MHz Clock = 25 MHz VDD = 2.6 V: Clock = 32 kHz Clock = 200 kHz Clock = 1 MHz Clock = 25 MHz T = 25 °C: VDD = 2.1 V, F < 1 MHz VDD = 2.1 V, F > 1 MHz VDD = 2.6 V, F < 1 MHz VDD = 2.6 V, F > 1 MHz Oscillator not running, VDD Monitor Disabled. T = 25 °C T = 60 °C T = 125 °C — — — — 8 22 0.09 2.2 — — — 5 µA µA mA mA — — — — 9 30 0.13 3 — — — 6.5 µA µA mA mA — — — — 90 90 118 118 — — — — µA/MHz µA/MHz µA/MHz µA/MHz — — — 2 3 50 — — — µA µA µA Notes: 1. 2. 3. 4. 5. For more information on VREGIN characteristics, see Table 2.6 on page 30. SYSCLK must be at least 32 kHz to enable debugging. Based on device characterization data; Not production tested. Does not include internal oscillator or internal regulator supply current. IDD can be estimated for frequencies 12 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by the frequency sensitivity number. For example: VDD = 2.6 V; F= 20 MHz, IDD = 7.3 mA – (25 MHz – 20 MHz) x 0.184 mA/MHz = 6.38 mA. 6. Idle IDD can be estimated for frequencies 1 MHz, the estimate should be the current at 25 MHz minus the difference in current indicated by the frequency sensitivity number. For example: VDD = 2.6 V; F= 5 MHz, Idle IDD = 3 mA – (25 MHz– 5 MHz) x 118 µA/MHz = 0.64 mA. Rev. 1.4 27 C8051F52x/F52xA/F53x/F53xA Table 2.3. ADC0 Electrical Characteristics VDD = 2.1 V, VREF = 1.5 V (REFSL=0), –40 to +125 °C unless otherwise specified. Parameter Conditions Min Typ Max Units DC Accuracy Resolution 12 bits Integral Nonlinearity — — ±3 LSB Differential Nonlinearity Guaranteed Monotonic — — ±1 LSB 1 –10 ±1 +10 LSB Offset Error Full Scale Error –20 ±1 +20 LSB Dynamic Performance (10 kHz sine-wave Single-ended input, 0 to 1 dB below Full Scale, 200 ksps) Signal-to-Noise Plus Distortion 60 66 — dB th — 74 — dB Total Harmonic Distortion Up to the 5 harmonic Spurious-Free Dynamic Range — 88 — dB Conversion Rate SAR Conversion Clock Burst Mode Oscillator Conversion Time in SAR Clocks2 Track/Hold Acquisition Time3,6 Throughput Rate4 — — — 1 — — — 13 — — 3 27 — — 200 MHz MHz clocks µs ksps 0 0 — — VREF VREF / n V 0 — — — 24 1.5 VREGIN — — V pF kΩ — — — — 1050 930 5 1 1400 — — — µA µA µs mV/V Analog Inputs ADC Input Voltage Range5 gain = 1.0 (default) gain = n Absolute Pin Voltage wrt to GND Sampling Capacitance Input Multiplexer Impedance Power Specifications Power Supply Current (from VDD) Burst Mode (Idle) Power-on Time Power Supply Rejection Operating Mode, 200 ksps Notes: 1. Represents one standard deviation from the mean. Offset and full-scale error can be removed through calibration. 2. An additional 2 FCLK cycles are required to start and complete a conversion. 3. Additional tracking time may be required depending on the output impedance connected to the ADC input. See Section “4.3.6. Settling Time Requirements” on page 60. 4. An increase in tracking time will decrease the ADC throughput. 5. See Section “4.4. Selectable Gain” on page 60 for more information about setting the gain. 6. Additional tracking time might be needed ifVDD < 2.0 V; See Section “11.2.1. VDD Monitor Thresholds and Minimum VDD” on page 108 for minimum VDD requirements. 28 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 2.4. Temperature Sensor Electrical Characteristics VDD = 2.1 V, VREF = 1.5 V (REFSL=0), –40 to +125 °C unless otherwise specified. Parameter Min Typ Max Units Linearity1 — 0.1 — °C 1 — 3.33 — mV/°C — ±100 — µV/°C Temp = 0 °C — 890 — mV Temp = 0 °C — ±15 — mV Tracking Time 12 — — µs Power Supply Current — 17 — µA Conditions Min Typ Max Units IDD ≈ 1 mA; No load on VREF pin and all other GPIO pins. 25 °C ambient (REFLV = 0) 25 °C ambient (REFLV = 1), VDD = 2.6 V 1.45 2.15 1.5 2.2 1.55 2.25 V VREF Short-Circuit Current — 2.5 — mA VREF Temperature Coefficient — 33 — ppm/°C Gain Gain Conditions Error2 Offset 1 Offset Error 2 Notes: 1. Includes ADC offset, gain, and linearity variations. 2. Represents one standard deviation from the mean. Table 2.5. Voltage Reference Electrical Characteristics VDD = 2.1 V; –40 to +125 °C unless otherwise specified. Parameter Internal Reference (REFBE = 1) Output Voltage Load Regulation Load = 0 to 200 µA to GND — 10 — ppm/µA VREF Turn-on Time 1 4.7 µF, 0.1 µF bypass — 21 — ms VREF Turn-on Time 2 0.1 µF bypass — 230 — µs — 2.1 — mV/V 0 — VDD V Sample Rate = 200 ksps; VREF = 1.5 V — 2.4 — µA BIASE = 1 — 22 — µA — 35 — µA Power Supply Rejection External Reference (REFBE = 0) Input Voltage Range Input Current Bias Generators ADC Bias Generator Power Consumption (Internal) Rev. 1.4 29 C8051F52x/F52xA/F53x/F53xA Table 2.6. Voltage Regulator Electrical Specifications VDD = 2.1 or 2.6 V; –40 to +125 °C unless otherwise specified. Parameter Input Voltage Range (VREGIN) Dropout Voltage (VDO) Output Voltage (VDD) Bias Current Dropout Indicator Detection Threshold Output Voltage Temperature Coefficient VREG Settling Time Conditions C8051F52x/53x C8051F52xA/53xA VDD connected to VREGIN VDD not connected to VREGIN C8051F52x-C/53x-C VDD connected to VREGIN VDD not connected to VREGIN Output Current = 1-50 mA Output Current = 1 to 50 mA REG0MD = 0 REG0MD = 1 2.1 V operation (REG0MD = 0; T = 25 °C) 2.6 V operation (REG0MD = 1; T = 25 °C) 50 mA load with VREGIN = 2.4 V and VDD load capacitor of 4.8 µF Min Typ Max Units 1 2.7 — 5.25 V 1.8 2.22 — — 2.7 5.25 2.0 2.22 — — — 10 2.75 5.25 — 2.0 2.5 — 2.1 2.6 1 2.25 2.75 5 — 1 5 — 75 — mV — 0.25 — mV/ºC — 250 — µs Notes: 1. The minimum input voltage is 2.7 V or VDD + VDO(max load), whichever is greater. 2. The minimum input voltage is 2.2 V or VDD + VDO(max load), whichever is greater. 30 Rev. 1.4 mV/mA V µA C8051F52x/F52xA/F53x/F53xA Table 2.7. Comparator Electrical Characteristics VREGIN = 2.7–5.25 V, –40 to +125 °C unless otherwise noted. All specifications apply to both Comparator0 and Comparator1 unless otherwise noted. Parameter Conditions Min Typ Max Units Response Time: Mode 0, Vcm1 = 1.5 V CP0+ – CP0– = 100 mV — 780 — ns CP0+ – CP0– = –100 mV — 980 — ns Response Time: Mode 1, Vcm1 = 1.5 V CP0+ – CP0– = 100 mV — 850 — ns CP0+ – CP0– = –100 mV — 1120 — ns Response Time: Mode 2, Vcm1 = 1.5 V CP0+ – CP0– = 100 mV — 870 — ns CP0+ – CP0– = –100 mV — 1310 — ns Response Time: Mode 3, Vcm1 = 1.5 V CP0+ – CP0– = 100 mV — 1980 — ns CP0+ – CP0– = –100 mV — 4770 — ns — 3 9 mV/V 0.7 2 mV Common-Mode Rejection Ratio Positive Hysteresis 1 CP0HYP1-0 = 00 — Positive Hysteresis 2 CP0HYP1-0 = 01 2 5 10 mV Positive Hysteresis 3 CP0HYP1-0 = 10 5 10 20 mV Positive Hysteresis 4 CP0HYP1-0 = 11 13 20 40 mV Negative Hysteresis 1 CP0HYN1-0 = 00 — 0.7 2 mV Negative Hysteresis 2 CP0HYN1-0 = 01 2 5 10 mV Negative Hysteresis 3 CP0HYN1-0 = 10 5 10 20 mV Negative Hysteresis 4 CP0HYN1-0 = 11 13 20 40 mV –0.25 — VDD + 0.25 V Inverting or Non-Inverting Input Voltage Range2 Input Capacitance2 — 4 — pF Input Bias Current — 0.5 — nA –15 — 15 mV — 1.5 — kΩ Power Supply Rejection2 — 0.2 4 mV/V Power-up Time — 2.3 — µs — 6 30 µA Input Offset Voltage Input Impedance Power Supply Mode 0 Supply Current at DC Mode 1 — 3 15 µA Mode 2 — 2 7.5 µA Mode 3 — 0.3 3.8 µA Notes: 1. Vcm is the common-mode voltage on CP0+ and CP0–. 2. Guaranteed by design and/or characterization. Rev. 1.4 31 C8051F52x/F52xA/F53x/F53xA Table 2.8. Reset Electrical Characteristics –40 to +125 °C unless otherwise specified. Parameter RST Output Low Voltage Conditions IOL = 8.5 mA, VDD = 2.1 V RST Input High Voltage RST Input Low Voltage Min Typ Max Units — — 0.8 V 0.7 x VREGIN — — V — — 0.3 x VREGIN V — — — — 330 160 130 80 — — — — kΩ kΩ kΩ kΩ RST Input Pullup Impedance VREGIN = 1.8 V VREGIN = 2.7 V VREGIN = 3.3 V VREGIN = 5 V Missing Clock Detector Timeout Time from last system clock rising edge to reset initiation 100 350 650 µs Delay between release of any reset source and code execution at location 0x0000 — — 350 µs 10 — — µs Reset Time Delay (TPORDelay)1 Minimum RST Low Time to Generate a System Reset VDD Monitor (VDDMON0) Low Threshold (VRST-LOW)1,2,3 C8051F52x/53x C8051F52xA/53xA C8051F52x-C/53x-C 1.8 1.65 1.65 1.9 1.75 1.75 2.0 1.8 1.8 V V V High Threshold (VRST-HIGH)3 C8051F52x/53x C8051F52xA/53xA C8051F52x-C/53x-C 2.1 2.25 2.25 2.2 2.3 2.3 2.3 2.4 2.45 V V V — 83 — µs — 1 2 µA Turn-on Time Supply Current VDD = 2.1 V Level-Sensitive VDD Monitor (VDDMON1) 1 Threshold (VRST1)1,2,3 C8051F52x-C/53x-C 1.6 1.75 1.9 V Supply Current C8051F52x-C/53x-C — 3 6 µA Notes: 1. Refer to Section “20. Device Specific Behavior” on page 210. 2. The POR threshold (VRST) is VRST-LOW or VRST1, whichever is higher. 3. The VRSTthreshold for power fail / brownout is the higher of VDDMON0 and VDDMON1 thresholds, if both are enabled. 32 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 2.9. Flash Electrical Characteristics VDD = 1.8 to 2.75 V; –40 to +125 ºC unless otherwise specified Parameter Conditions Min Typ Max Units Flash Size ’F520/0A/1/1A and ’F530/0A/1/1A ’F523/3A/4/4A and ’F533/3A/4/4A ’F526/6A/7/7A and ’F536/6A/7/7A 7680 4096 2048 — — bytes Endurance2 VDD ≥ VRST-HIGH1 20 k 150 k — Erase/Write 27 32 38 ms 57 65 74 µs VRST-HIGH1 — — V Erase Cycle Time Write Cycle Time VDD Write/Erase Operations Notes: 1. See Table 2.8 on page 32 for the VRST-HIGH specification. 2. For –I (industrial Grade) parts, flash should be programmed (erase/write) at a minimum temperature of 0 °C for reliable flash operation across the entire temperature range of –40 to +125 °C. This minimum programming temperature does not apply to –A (Automotive Grade) parts. Table 2.10. Port I/O DC Electrical Characteristics VREGIN = 2.7 to 5.25 V, –40 to +125 °C unless otherwise specified Parameters Conditions Min Output High IOH = –3 mA, Port I/O push-pull Voltage IOH = –10 µA, Port I/O push-pull IOH = –10 mA, Port I/O push-pull Typ — VREGIN – 0.4 VREGIN – 0.02 — — VREGIN – 0.7 Output Low VREGIN = 2.7 V: Voltage IOL = 70 µA IOL = 8.5 mA VREGIN = 5.25 V: IOL = 70 µA IOL = 8.5 mA Max Units — — — V — — — — 45 550 — — — — 40 400 Input High Voltage VREGIN x 0.7 — — V Input Low Voltage — — VREGIN x 0.3 V Weak Pullup Off — — ±2 C8051F52xA/53xA: Weak Pullup On, VIN = 0 V; VREGIN = 1.8 V — 5 15 C8051F52x/52xA/53x/53xA: Weak Pullup On, VIN = 0 V; VREGIN = 2.7 V Weak Pullup On, VIN = 0 V; VREGIN = 5.25 V — — 20 65 50 115 Input Leakage Current Rev. 1.4 mV µA 33 C8051F52x/F52xA/F53x/F53xA Table 2.11. Internal Oscillator Electrical Characteristics VDD = 1.8 to 2.75 V, –40 to +125 °C unless otherwise specified; Using factory-calibrated settings. Parameter Oscillator Frequency Conditions 1 Min Typ Max Units 3 24.5 + 0.5% MHz IFCN = 111b VDD > VREGMIN2 24.5 – 0.5% 24.5 IFCN = 111b VDD < VREGMIN2 24.5 – 1.0% 24.53 24.5 + 1.0% Oscillator On OSCICN[7:6] = 11b — 800 1100 µA — — — 67 77 117 — — 300 µA µA µA T = 25 °C T = 85 °C T = 125 °C — — — 2 3 50 — — — µA µA µA OSCICN[7:6] = 00b ZTCEN = 04 — — 1 µs OSCICN[7:6] = 00b ZTCEN = 1 — 5 — Instruction Cycles Constant Temperature — 0.10 — %/V Constant Supply TC1 TC2 — — 5.0 –0.65 — — ppm/°C ppm/°C2 Oscillator Suspend OSCICN[7:6] = 00b ZTCEN = 1 Oscillator Supply Current (from VDD) T = 25 °C T = 85 °C T = 125 °C Oscillator Suspend OSCICN[7:6] = 00b ZTCEN = 0 Wake-Up Time From Suspend Power Supply Sensitivity Temperature Sensitivity5 Notes: 1. See Section “11.2.1. VDD Monitor Thresholds and Minimum VDD” on page 108 for minimum VDD requirements. 2. VREGMIN is the minimum output of the voltage regulator for its low setting (REG0CN: REG0MD = 0b). See Table 2.6, “Voltage Regulator Electrical Specifications,” on page 30. 3. This is the average frequency across the operating temperature range. 4. See “20.7. Internal Oscillator Suspend Mode” on page 212 for ZTCEN setting in older silicon revisions. 5. Use temperature coefficients TC1 and TC2 to calculate the new internal oscillator frequency using the following equation: f(T) = f0 x (1 + TC1 x (T – T0) + TC2 x (T – T0)2) where f0 is the internal oscillator frequency at 25 °C and T0 is 25 °C. 34 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 3. Pinout and Package Definitions RST/C2CK 1 10 P0.1/C2D P0.0/VREF 2 9 P0.2/XTAL1 GND 3 8 P0.3/XTAL2 VDD 4 7 P0.4/TX VREGIN 5 6 P0.5/CNVSTR/RX RST/C2CK 1 10 P0.1/C2D P0.0/VREF 2 9 P0.2/XTAL1 GND 3 8 P0.3/XTAL2/TX VDD 4 7 P0.4/RX VREGIN 5 6 P0.5/CNVSTR C8051F52xA/52x-C Top View GND C8051F52x Top View GND Figure 3.1. DFN-10 Pinout Diagram (Top View) Rev. 1.4 35 C8051F52x/F52xA/F53x/F53xA Table 3.1. Pin Definitions for the C8051F52x and C8051F52xA (DFN 10) Name Pin Numbers Type Description D I/O Device Reset. Open-drain output of internal POR or VDD monitor. An external source can initiate a system reset by driving this pin low for at least the minimum RST low time to generate a system reset, as defined in Table 2.8 on page 32. A 1 kΩ pullup to VREGIN is recommended. See Reset Sources Section for a complete description. ‘F52xA ‘F52x ‘F52x-C RST/ 1 1 C2CK D I/O Clock signal for the C2 Debug Interface. P0.0/ 2 2 D I/O or Port 0.0. See Port I/O Section for a complete description. A In A O or D In VREF External VREF Input. See VREF Section. GND 3 3 Ground. VDD 4 4 Core Supply Voltage. VREGIN 5 5 On-Chip Voltage Regulator Input. P0.5/RX*/ 6 — D In CNVSTR P0.5/ D I/O or Port 0.5. See Port I/O Section for a complete description. A In — 6 D I/O or Port 0.5. See Port I/O Section for a complete description. A In D In CNVSTR External Converter start input for the ADC0, see Section “4. 12Bit ADC (ADC0)” on page 52 for a complete description. External Converter start input for the ADC0, see Section “4. 12Bit ADC (ADC0)” on page 52 for a complete description. P0.4/TX* 7 — D I/O or Port 0.4. See Port I/O Section for a complete description. A In P0.4/RX* — 7 D I/O or Port 0.4. See Port I/O Section for a complete description. A In P0.3 8 — D I/O or Port 0.3. See Port I/O Section for a complete description. A In XTAL2 D I/O External Clock Output. For an external crystal or resonator, this pin is the excitation driver. This pin is the external clock input for CMOS, capacitor, or RC oscillator configurations. See Section “14. Oscillators” on page 135. Note: Please refer to Section “20. Device Specific Behavior” on page 210. 36 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 3.1. Pin Definitions for the C8051F52x and C8051F52xA (DFN 10) (Continued) Name Pin Numbers Type Description ‘F52xA ‘F52x ‘F52x-C P0.3/TX*/ — 8 D I/O XTAL2 P0.2 9 9 XTAL1 P0.1/ C2D D I/O or Port 0.3. See Port I/O Section for a complete description. A In D I/O or Port 0.2. See Port I/O Section for a complete description. A In 10 10 External Clock Output. For an external crystal or resonator, this pin is the excitation driver. This pin is the external clock input for CMOS, capacitor, or RC oscillator configurations. See Section “14. Oscillators” on page 135. External Clock Input. This pin is the external oscillator return for a crystal or resonator. Section “14. Oscillators” on page 135. D I/O or Port 0.1. See Port I/O Section for a complete description. A In D I/O Bi-directional data signal for the C2 Debug Interface Note: Please refer to Section “20. Device Specific Behavior” on page 210. Rev. 1.4 37 C8051F52x/F52xA/F53x/F53xA Figure 3.2. DFN-10 Package Diagram Table 3.2. DFN-10 Package Diagram Dimensions Dimension Min Nom Max A A1 b D D2 e E E2 L L1 aaa bbb ddd eee 0.80 0.00 0.18 0.90 0.02 0.25 3.00 BSC. 1.65 0.50 BSC. 3.00 BSC. 2.38 0.40 — — — — — 1.00 0.05 0.30 1.50 2.23 0.30 0.00 — — — — 1.80 2.53 0.50 0.15 0.15 0.15 0.05 0.08 Notes: 1. All dimensions shown are in millimeters (mm) unless otherwise noted. 2. Dimensioning and Tolerancing per ANSI Y14.5M-1994. 3. This drawing conforms to JEDEC outline MO-220, variation VEED except for custom features D2, E2, and L, which are toleranced per supplier designation. 4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components. 38 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Figure 3.3. DFN-10 Landing Diagram Table 3.3. DFN-10 Landing Diagram Dimensions Dimension Min Max C1 E X1 X2 Y1 Y2 2.90 3.00 0.50 BSC. 0.20 1.70 0.70 2.45 0.30 1.80 0.80 2.55 Notes: General 1. All dimensions shown are in millimeters (mm) unless otherwise noted. 2. This land pattern design is based on the IPC-7351 guidelines. Solder Mask Design 3. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is to be 60 µm minimum, all the way around the pad. Stencil Design 4. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder paste release. 5. The stencil thickness should be 0.125 mm (5 mils). 6. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads. 7. A 4x1 array of 1.60 x 0.45 mm openings on 0.65 mm pitch should be used for the center ground pad. Card Assembly 8. A No-Clean, Type-3 solder paste is recommended. 9. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components. Rev. 1.4 39 C8051F52x/F52xA/F53x/F53xA 20 P0.3 P0.2 1 20 P0.3/TX P0.1 2 19 P0.4/TX P0.1 2 19 P0.4/RX RST/C2CK 3 18 P0.5/RX RST/C2CK 3 18 P0.5 P0.0/VREF 4 17 P0.6/C2D P0.0/VREF 4 17 P0.6/C2D GND 5 16 P0.7/XTAL1 GND 5 16 P0.7/XTAL1 VDD 6 15 P1.0/XTAL2 VDD 6 15 P1.0/XTAL2 VREGIN 7 14 P1.1 VREGIN 7 14 P1.1 P1.7 8 13 P1.2/CNVSTR P1.7 8 13 P1.2/CNVSTR P1.6 9 12 P1.3 P1.6 9 12 P1.3 P1.5 10 11 P1.4 P1.5 10 11 P1.4 C8051F53x 1 C8051F53xA/53x-C P0.2 Figure 3.4. TSSOP-20 Pinout Diagram (Top View) Table 3.4. Pin Definitions for the C8051F53x and C805153xA (TSSOP 20) Name Pin Numbers Type Description ‘F53xA ‘F53x ‘F53x-C P0.2 1 1 D I/O or Port 0.2. See Port I/O Section for a complete description. A In P0.1 2 2 D I/O or Port 0.1. See Port I/O Section for a complete description. A In RST/ 3 3 C2CK D I/O D I/O Device Reset. Open-drain output of internal POR or VDD monitor. An external source can initiate a system reset by driving this pin low for at least the minimum RST low time to generate a system reset, as defined in Table 2.8 on page 32. A 1 kΩ pullup to VREGIN is recommended. See Reset Sources Section for a complete description. Clock signal for the C2 Debug Interface. P0.0/ 4 4 D I/O or Port 0.0. See Port I/O Section for a complete description. A In A O or D In VREF External VREF Input. See VREF Section. GND 5 5 Ground. VDD 6 6 Core Supply Voltage. *Note: Please refer to Section “20. Device Specific Behavior” on page 210. 40 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 3.4. Pin Definitions for the C8051F53x and C805153xA (TSSOP 20) (Continued) Name Pin Numbers Type Description ‘F53xA ‘F53x ‘F53x-C VREGIN 7 7 On-Chip Voltage Regulator Input. P1.7 8 8 D I/O or Port 1.7. See Port I/O Section for a complete description. A In P1.6 9 9 D I/O or Port 1.6. See Port I/O Section for a complete description. A In P1.5 10 10 D I/O or Port 1.5. See Port I/O Section for a complete description. A In P1.4 11 11 D I/O or Port 1.4. See Port I/O Section for a complete description. A In P1.3 12 12 D I/O or Port 1.3. See Port I/O Section for a complete description. A In P1.2/ 13 13 D I/O or Port 1.2. See Port I/O Section for a complete description. A In D In CNVSTR External Converter start input for the ADC0, see Section “4. 12Bit ADC (ADC0)” on page 52 for a complete description. P1.1 14 14 D I/O or Port 1.1. See Port I/O Section for a complete description. A In P1.0/ 15 15 D I/O or Port 1.0. See Port I/O Section for a complete description. A In D I/O XTAL2 P0.7/ 16 16 D I/O or Port 0.7. See Port I/O Section for a complete description. A In External Clock Input. This pin is the external oscillator return for A In a crystal or resonator. Section “14. Oscillators” on page 135. 17 17 D I/O or Port 0.6. See Port I/O Section for a complete description. A In XTAL1 P0.6/ External Clock Output. For an external crystal or resonator, this pin is the excitation driver. This pin is the external clock input for CMOS, capacitor, or RC oscillator configurations. See Section “14. Oscillators” on page 135. D I/O C2D Bi-directional data signal for the C2 Debug Interface. P0.5/RX* 18 — D I/O or Port 0.5. See Port I/O Section for a complete description. A In P0.5 — 18 D I/O or Port 0.5. See Port I/O Section for a complete description. A In *Note: Please refer to Section “20. Device Specific Behavior” on page 210. Rev. 1.4 41 C8051F52x/F52xA/F53x/F53xA Table 3.4. Pin Definitions for the C8051F53x and C805153xA (TSSOP 20) (Continued) Name Pin Numbers Type Description ‘F53xA ‘F53x ‘F53x-C P0.4/TX* 19 — D I/O or Port 0.4. See Port I/O Section for a complete description. A In P0.4/RX* — 19 D I/O or Port 0.4. See Port I/O Section for a complete description. A In P0.3 20 — D I/O or Port 0.3. See Port I/O Section for a complete description. A In P0.3/TX* — 20 D I/O or Port 0.3. See Port I/O Section for a complete description. A In *Note: Please refer to Section “20. Device Specific Behavior” on page 210. 42 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA θ1 Figure 3.5. TSSOP-20 Package Diagram Table 3.5. TSSOP-20 Package Diagram Dimensions Symbol Min A A1 A2 b c D e E E1 L θ1 aaa bbb ddd — 0.05 0.80 0.19 0.09 6.40 4.30 0.45 0° Nom — — 1.00 — — 6.50 0.65 BSC. 6.40 BSC. 4.40 0.60 — 0.10 0.10 0.20 Max 1.20 0.15 1.05 0.30 0.20 6.60 4.50 0.75 8° Notes: 1. All dimensions shown are in millimeters (mm). 2. Dimensioning and Tolerancing per ANSI Y14.5M-1994. 3. This drawing conforms to JEDEC outline MO-153, variation AC. 4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components. Rev. 1.4 43 C8051F52x/F52xA/F53x/F53xA Figure 3.6. TSSOP-20 Landing Diagram Table 3.6. TSSOP-20 Landing Diagram Dimensions Symbol Min C E X1 Y1 5.80 Max 5.90 0.65 BSC. 0.35 1.35 0.45 1.45 Notes: General 1. All dimensions shown are in millimeters (mm) unless otherwise noted. 2. This land pattern design is based on the IPC-7351 guidelines. Solder Mask Design 3. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is to be 60 µm minimum, all the way around the pad. Stencil Design 4. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder paste release. 5. The stencil thickness should be 0.125 mm (5 mils). 6. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads. Card Assembly 7. A No-Clean, Type-3 solder paste is recommended. 8. The recommended card reflow profile is per the JEDEC/IPC J-STD020 specification for Small Body Components. 44 Rev. 1.4 P0.1 P0.2 P0.3 P0.4/TX P0.5/RX 20 19 18 17 16 C8051F52x/F52xA/F53x/F53xA RST/C2CK 1 15 P0.6/C2D P0.0/VREF 2 14 P0.7/XTAL1 GND 3 13 P1.0/XTAL2 VDD 4 12 P1.1 VREGIN 5 11 P1.2/CNVSTR RST/C2CK 1 15 P0.6/C2D P0.0/VREF 2 14 P0.7/XTAL1 GND 3 13 P1.0/XTAL2 VDD 4 12 P1.1 VREGIN 5 11 P1.2/CNVSTR C8051F53xA/53x-C Top View 10 P1.3 P0.5 16 9 P1.4 P0.4/RX 17 8 P1.5 P0.3/TX 18 7 P1.6 P0.2 19 6 P0.1 20 P1.7 GND C8051F53x Top View 10 P1.3 8 P1.5 9 7 P1.6 P1.4 6 P1.7 GND Figure 3.7. QFN-20 Pinout Diagram (Top View) Rev. 1.4 45 C8051F52x/F52xA/F53x/F53xA Table 3.7. Pin Definitions for the C8051F53x and C805153xA (QFN 20) Name Pin Numbers Type Description D I/O Device Reset. Open-drain output of internal POR or VDD monitor. An external source can initiate a system reset by driving this pin low for at least the minimum RST low time to generate a system reset, as defined in Table 2.8 on page 32. A 1 kΩ pullup to VREGIN is recommended. See Reset Sources Section for a complete description. ‘F53xA ‘F53x ‘F53x-C RST/ 1 1 C2CK D I/O Clock signal for the C2 Debug Interface. P0.0/ 2 2 D I/O or Port 0.0. See Port I/O Section for a complete description. A In A O or D In VREF External VREF Input. See VREF Section. GND 3 3 Ground. VDD 4 4 Core Supply Voltage. VREGIN 5 5 On-Chip Voltage Regulator Input. P1.7 6 6 D I/O or Port 1.7. See Port I/O Section for a complete description. A In P1.6 7 7 D I/O or Port 1.6. See Port I/O Section for a complete description. A In P1.5 8 8 D I/O or Port 1.5. See Port I/O Section for a complete description. A In P1.4 9 9 D I/O or Port 1.4. See Port I/O Section for a complete description. A In P1.3 10 10 D I/O or Port 1.3. See Port I/O Section for a complete description. A In P1.2/ 11 11 D I/O or Port 1.2. See Port I/O Section for a complete description. A In D In CNVSTR P1.1 12 12 External Converter start input for the ADC0, see Section “4. 12Bit ADC (ADC0)” on page 52 for a complete description. D I/O or Port 1.1. See Port I/O Section for a complete description. A In Note: Please refer to Section “20. Device Specific Behavior” on page 210. 46 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 3.7. Pin Definitions for the C8051F53x and C805153xA (QFN 20) (Continued) Name Pin Numbers Type Description ‘F53xA ‘F53x ‘F53x-C P1.0/ 13 13 D I/O XTAL2 P0.7/ 14 14 XTAL1 P0.6/ D I/O or Port 1.0. See Port I/O Section for a complete description. A In D I/O or Port 0.7. See Port I/O Section for a complete description. A In 15 15 External Clock Input. This pin is the external oscillator return for a crystal or resonator. See Oscillator Section. D I/O or Port 0.6. See Port I/O Section for a complete description. A In D I/O C2D External Clock Output. For an external crystal or resonator, this pin is the excitation driver. This pin is the external clock input for CMOS, capacitor, or RC oscillator configurations. Section “14. Oscillators” on page 135. Bi-directional data signal for the C2 Debug Interface. P0.5/RX* 16 — D I/O or Port 0.5. See Port I/O Section for a complete description. A In P0.5 — 16 D I/O or Port 0.5. See Port I/O Section for a complete description. A In P0.4/TX* 17 — D I/O or Port 0.4. See Port I/O Section for a complete description. A In P0.4/RX* — 17 D I/O or Port 0.4. See Port I/O Section for a complete description. A In P0.3 18 — D I/O or Port 0.3. See Port I/O Section for a complete description. A In P0.3/TX* — 18 D I/O or Port 0.3. See Port I/O Section for a complete description. A In P0.2 19 19 D I/O or Port 0.2. See Port I/O Section for a complete description. A In P0.1 20 20 D I/O or Port 0.1. See Port I/O Section for a complete description. A In Note: Please refer to Section “20. Device Specific Behavior” on page 210. Rev. 1.4 47 C8051F52x/F52xA/F53x/F53xA Figure 3.8. QFN-20 Package Diagram* *Note: The Package Dimensions are given in Table 3.8, “QFN-20 Package Diagram Dimensions,” on page 49. 48 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 3.8. QFN-20 Package Diagram Dimensions Dimension MIN NOM MAX A A1 b D D2 e E E2 L L1 aaa bbb ddd eee Z Y 0.80 0.00 0.18 0.90 0.02 0.25 4.00 BSC. 2.70 0.50 BSC. 4.00 BSC. 2.70 0.40 — — — — — 0.43 0.18 1.00 0.05 0.30 2.55 2.55 0.30 0.00 — — — — — — 2.85 2.85 0.50 0.15 0.15 0.10 0.05 0.08 — — Notes: 1. All dimensions shown are in millimeters (mm) unless otherwise noted. 2. Dimensioning and Tolerancing per ANSI Y14.5M-1994. 3. This drawing conforms to JEDEC outline MO-220, variation VGGD except for custom features D2, E2, Z, Y, L, and L1, which are toleranced per supplier designation. 4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components. Rev. 1.4 49 C8051F52x/F52xA/F53x/F53xA Figure 3.9. QFN-20 Landing Diagram* Note: The Landing Dimensions are given in Table 3.9, “QFN-20 Landing Diagram Dimensions,” on page 51. 50 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 3.9. QFN-20 Landing Diagram Dimensions Symbol Min Max C1 C2 E X1 X2 Y1 Y2 3.90 3.90 4.00 4.00 0.50 BSC. 0.20 2.75 0.65 2.75 0.30 2.85 0.75 2.85 Notes: General 1. All dimensions shown are in millimeters (mm) unless otherwise noted. 2. This land pattern design is based on the IPC-7351 guidelines. Solder Mask Design 3. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is to be 60 µm minimum, all the way around the pad. Stencil Design 4. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder paste release. 5. The stencil thickness should be 0.125 mm (5 mils). 6. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads. 7. A 2x2 array of 1.10 x 1.10 mm openings on 1.30 mm pitch should be used for the center ground pad. Card Assembly 8. A No-Clean, Type-3 solder paste is recommended. 9. The recommended card reflow profile is per the JEDEC/IPC J-STD020 specification for Small Body Components. Rev. 1.4 51 C8051F52x/F52xA/F53x/F53xA 4. 12-Bit ADC (ADC0) ADC0TK ADC0CN AD0PWR3 AD0PWR2 AD0PWR1 AD0PWR0 AD0TM1 AD0TM0 AD0TK1 AD0TK0 AD0EN BURSTEN AD0INT AD0BUSY AD0WINT AD0LJST AD0CM1 AD0CM0 The ADC0 on the C8051F52x/F52xA/F53x/F53xA Family consists of an analog multiplexer (AMUX0) with 16/6 total input selections, and a 200 ksps, 12-bit successive-approximation-register (SAR) ADC with integrated track-and-hold, programmable window detector, programmable gain, and hardware accumulator. The ADC0 subsystem has a special Burst Mode which can automatically enable ADC0, capture and accumulate samples, then place ADC0 in a low power shutdown mode without CPU intervention. The AMUX0, data conversion modes, and window detector are all configurable under software control via the Special Function Registers shown in Figure 4.1. ADC0 inputs are single-ended and may be configured to measure P0.0-P1.7, the Temperature Sensor output, VDD, or GND with respect to GND. The voltage reference for the ADC is selected as described in Section “5. Voltage Reference” on page 72. ADC0 is enabled when the AD0EN bit in the ADC0 Control register (ADC0CN) is set to logic 1, or when performing conversions in Burst Mode. ADC0 is in low power shutdown when AD0EN is logic 0 and no Burst Mode conversions are taking place. Start Conversion Burst Mode Oscillator 25 MHz Max *Available on ‘F53x/’F53xA devices 19-to-1 AMUX0 Burst Mode Logic 12-Bit SAR Selectable Gain ADC VDD ADC0GNH ADC0GNL ADC0GNA Temp Sensor 00 AD0BUSY (W) 01 Timer 1 Overflow 10 CNVSTR Input 11 Timer 2 Overflow Accumulator AD0TM1:0 AD0PRE AD0POST FCLK REF P1.7* Start Conversion ADC0L SYSCLK P0.6* P0.7* P1.0* VDD FCLK P0.0 ADC0H ADC0MX4 ADC0MX3 ADC0MX2 ADC0MX1 ADC0MX0 ADC0MX AD0WINT AD0SC4 AD0SC3 AD0SC2 AD0SC1 AD0SC0 AD0RPT1 AD0RPT0 GAINEN GND ADC0LTH ADC0LTL ADC0CF ADC0GTH ADC0GTL 32 Window Compare Logic Figure 4.1. ADC0 Functional Block Diagram 4.1. Analog Multiplexer AMUX0 selects the input channel to the ADC. Any of the following may be selected as an input: P0.0– P1.7, the on-chip temperature sensor, the core power supply (VDD), or ground (GND). ADC0 is singleended and all signals measured are with respect to GND. The ADC0 input channels are selected using the ADC0MX register as described in SFR Definition 4.4. Important Note About ADC0 Input Configuration: Port pins selected as ADC0 inputs should be configured as analog inputs, and should be skipped by the Digital Crossbar. To configure a Port pin for analog input, set to 0 the corresponding bit in register PnMDIN (for n = 0,1). To force the Crossbar to skip a Port pin, set to 1 the corresponding bit in register PnSKIP (for n = 0,1). See Section “13. Port Input/Output” on page 120 for more Port I/O configuration details. Rev. 1.4 52 C8051F52x/F52xA/F53x/F53xA 4.2. Temperature Sensor An on-chip temperature sensor is included on the C8051F52x/F52xA/F53x/F53xA devices which can be directly accessed via the ADC0 multiplexer. To use ADC0 to measure the temperature sensor, the ADC multiplexer channel should be configured to connect to the temperature sensor. The temperature sensor transfer function is shown in Figure 5.2. The output voltage (VTEMP) is the positive ADC input selected by bits AD0MX[4:0] in register ADC0MX. The TEMPE bit in register REF0CN enables/disables the temperature sensor, as described in SFR Definition 5.1. While disabled, the temperature sensor defaults to a high impedance state and any ADC measurements performed on the sensor will result in meaningless data. Refer to Table 5.1 for the slope and offset parameters of the temperature sensor. VTEMP = (Slope x TempC) + Offset TempC = (VTEMP - Offset) / Slope Voltage Slope ( V / deg C) Offset ( V at 0 Celsius) Temperature Figure 4.2. Typical Temperature Sensor Transfer Function 53 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 4.3. ADC0 Operation In a typical system, ADC0 is configured using the following steps: 1. If a gain adjustment is required, refer to Section “4.4. Selectable Gain” on page 60. 2. Choose the start of conversion source. 3. Choose Normal Mode or Burst Mode operation. 4. If Burst Mode, choose the ADC0 Idle Power State and set the Power-Up Time. 5. Choose the tracking mode. Note that Pre-Tracking Mode can only be used with Normal Mode. 6. Calculate required settling time and set the post convert-start tracking time using the AD0TK bits. 7. Choose the repeat count. 8. Choose the output word justification (Right-Justified or Left-Justified). 9. Enable or disable the End of Conversion and Window Comparator Interrupts. 4.3.1. Starting a Conversion A conversion can be initiated in one of four ways, depending on the programmed states of the ADC0 Start of Conversion Mode bits (AD0CM1–0) in register ADC0CN. Conversions may be initiated by one of the following:  Writing a 1 to the AD0BUSY bit of register ADC0CN A rising edge on the CNVSTR input signal (pin P0.6)  A Timer 1 overflow (i.e., timed continuous conversions)  A Timer 2 overflow (i.e., timed continuous conversions)  Writing a 1 to AD0BUSY provides software control of ADC0 whereby conversions are performed "ondemand.” During conversion, the AD0BUSY bit is set to logic 1 and reset to logic 0 when the conversion is complete. The falling edge of AD0BUSY triggers an interrupt (when enabled) and sets the ADC0 interrupt flag (AD0INT). Note: When polling for ADC conversion completions, the ADC0 interrupt flag (AD0INT) should be used. Converted data is available in the ADC0 data registers, ADC0H:ADC0L, when bit AD0INT is logic 1. Note that when Timer 2 overflows are used as the conversion source, Low Byte overflows are used if Timer2 is in 8-bit mode; High byte overflows are used if Timer 2 is in 16-bit mode. See Section “18. Timers” on page 182 for timer configuration. Important Note: The CNVSTR input pin also functions as Port pin P0.5 on C8051F52x/52xA devices and P1.2 on C8051F53x/53xA devices. When the CNVSTR input is used as the ADC0 conversion source, Port pin P0.5 or P1.2 should be skipped by the Digital Crossbar. To configure the Crossbar to skip P0.5 or P1.2, set to 1 to the appropriate bit in the PnSKIP register. See Section “13. Port Input/Output” on page 120 for details on Port I/O configuration. 4.3.2. Tracking Modes Each ADC0 conversion must be preceded by a minimum tracking time for the converted result to be accurate, as shown in Table 2.3 on page 28. ADC0 has three tracking modes: Pre-Tracking, Post-Tracking, and Dual-Tracking. Pre-Tracking Mode provides the minimum delay between the convert start signal and end of conversion by tracking continuously before the convert start signal. This mode requires software management in order to meet minimum tracking requirements. In Post-Tracking Mode, a programmable tracking time starts after the convert start signal and is managed by hardware. Dual-Tracking Mode maximizes tracking time by tracking before and after the convert start signal. Figure 4.3 shows examples of the three tracking modes. Pre-Tracking Mode is selected when AD0TM is set to 10b. Conversions are started immediately following the convert start signal. ADC0 is tracking continuously when not performing a conversion. Software must allow at least the minimum tracking time between each end of conversion and the next convert start signal. The minimum tracking time must also be met prior to the first convert start signal after ADC0 is enabled. Rev. 1.4 54 C8051F52x/F52xA/F53x/F53xA Post-Tracking Mode is selected when AD0TM is set to 01b. A programmable tracking time based on AD0TK is started immediately following the convert start signal. Conversions are started after the programmed tracking time ends. After a conversion is complete, ADC0 does not track the input. Rather, the sampling capacitor remains disconnected from the input making the input pin high-impedance until the next convert start signal. Dual-Tracking Mode is selected when AD0TM is set to 11b. A programmable tracking time based on AD0TK is started immediately following the convert start signal. Conversions are started after the programmed tracking time ends. After a conversion is complete, ADC0 tracks continuously until the next conversion is started. Depending on the output connected to the ADC input, additional tracking time, more than is specified in Table 2.3 on page 28, may be required after changing MUX settings. See the settling time requirements described in Section “4.3.6. Settling Time Requirements” on page 60. Convert Start Pre-Tracking AD0TM = 10 Track Post-Tracking AD0TM= 01 Idle Track Convert Idle Track Convert.. Dual-Tracking AD0TM = 11 Track Track Convert Track Track Convert.. Convert Track Convert ... Figure 4.3. ADC0 Tracking Modes 4.3.3. Timing ADC0 has a maximum conversion speed specified in Table 2.3 on page 28. ADC0 is clocked from the ADC0 Subsystem Clock (FCLK). The source of FCLK is selected based on the BURSTEN bit. When BURSTEN is logic 0, FCLK is derived from the current system clock. When BURSTEN is logic 1, FCLK is derived from the Burst Mode Oscillator, which is an independent clock source whose maximum frequency is specified in Table 2.3 on page 28. When ADC0 is performing a conversion, it requires a clock source that is typically slower than FCLK. The ADC0 SAR conversion clock (SAR clock) is a divided version of FCLK. The divide ratio can be configured using the AD0SC bits in the ADC0CF register. The maximum SAR clock frequency is listed in Table 2.3 on page 28. ADC0 can be in one of three states at any given time: tracking, converting, or idle. Tracking time depends on the tracking mode selected. For Pre-Tracking Mode, tracking is managed by software and ADC0 starts conversions immediately following the convert start signal. For Post-Tracking and Dual-Tracking Modes, the tracking time after the convert start signal is equal to the value determined by the AD0TK bits plus 2 FCLK cycles. Tracking is immediately followed by a conversion. The ADC0 conversion time is always 13 SAR clock cycles plus an additional 2 FCLK cycles to start and complete a conversion. Figure 4.4 shows timing diagrams for a conversion in Pre-Tracking Mode and tracking plus conversion in Post-Tracking or Dual-Tracking Mode. In this example, repeat count is set to one. 55 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Convert Start Pre-Tracking Mode Time F S1 S2 ADC0 State ... S12 S13 F Convert AD0INT Flag Post-Tracking or Dual-Tracking Modes (AD0TK = ‘00') Time F S1 ADC0 State S2 F F S1 ... S2 Track S12 S13 F Convert AD0INT Flag Key F Sn Equal to one period of FCLK. Each Sn is equal to one period of the SAR clock. Figure 4.4. 12-Bit ADC Tracking Mode Example Rev. 1.4 56 C8051F52x/F52xA/F53x/F53xA 4.3.4. Burst Mode Burst Mode is a power saving feature that allows ADC0 to remain in a very low power state between conversions. When Burst Mode is enabled, ADC0 wakes from a very low power state, accumulates 1, 4, 8, or 16 samples using an internal Burst Mode Oscillator, then re-enters a very low power state. Since the Burst Mode clock is independent of the system clock, ADC0 can perform multiple conversions then enter a very low power state within a single system clock cycle, even if the system clock is slow (e.g. 32.768 kHz), or suspended. Burst Mode is enabled by setting BURSTEN to logic 1. When in Burst Mode, AD0EN controls the ADC0 idle power state (i.e., the state ADC0 enters when not tracking or performing conversions). If AD0EN is set to logic 0, ADC0 is powered down after each burst. If AD0EN is set to logic 1, ADC0 remains enabled after each burst. On each convert start signal, ADC0 is awakened from its Idle Power State. If ADC0 is powered down, it will automatically power up and wait the programmable Power-Up Time controlled by the AD0PWR bits. Otherwise, ADC0 will start tracking and converting immediately. Figure 4.5 shows an example of Burst Mode Operation with a slow system clock and a repeat count of 4. Important Note: When Burst Mode is enabled, only Post-Tracking and Dual-Tracking modes can be used. When Burst Mode is enabled, a single convert start will initiate a number of conversions equal to the repeat count. When Burst Mode is disabled, a convert start is required to initiate each conversion. In both modes, the ADC0 End of Conversion Interrupt Flag (AD0INT) will be set after “repeat count” conversions have been accumulated. Similarly, the Window Comparator will not compare the result to the greater-than and less-than registers until “repeat count” conversions have been accumulated. Note: When using Burst Mode, care must be taken to issue a convert start signal no faster than once every four SYSCLK periods. This includes external convert start signals. 57 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA System Clock Convert Start (AD0BUSY or Timer Overflow) Post-Tracking AD0TM = 01 AD0EN = 0 Powered Down Power-Up and Idle T C T C T C T C Powered Down Power-Up and Idle T C.. Dual-Tracking AD0TM = 11 AD0EN = 0 Powered Down Power-Up and Track T C T C T C T C Powered Down Power-Up and Track T C.. AD0PWR Post-Tracking AD0TM = 01 AD0EN = 1 Idle T C T C T C T C Idle T C T C T C.. Dual-Tracking AD0TM = 11 AD0EN = 1 Track T C T C T C T C Track T C T C T C.. T = Tracking C = Converting Convert Start (CNVSTR) Post-Tracking AD0TM = 01 AD0EN = 0 Powered Down Power-Up and Idle T C Powered Down Power-Up and Idle T C.. Dual-Tracking AD0TM = 11 AD0EN = 0 Powered Down Power-Up and Track T C Powered Down Power-Up and Track T C.. AD0PWR Post-Tracking AD0TM = 01 AD0EN = 1 Idle T C Idle T C Idle.. Dual-Tracking AD0TM = 11 AD0EN = 1 Track T C Track T C Track.. T = Tracking C = Converting Figure 4.5. 12-Bit ADC Burst Mode Example with Repeat Count Set to 4 Rev. 1.4 58 C8051F52x/F52xA/F53x/F53xA 4.3.5. Output Conversion Code The registers ADC0H and ADC0L contain the high and low bytes of the output conversion code. When the repeat count is set to 1, conversion codes are represented in 12-bit unsigned integer format and the output conversion code is updated after each conversion. Inputs are measured from 0 to VREF x 4095/4096. Data can be right-justified or left-justified, depending on the setting of the AD0LJST bit (ADC0CN.2). Unused bits in the ADC0H and ADC0L registers are set to 0. Example codes are shown below for both right-justified and left-justified data. Input Voltage Right-Justified ADC0H:ADC0L (AD0LJST = 0) Left-Justified ADC0H:ADC0L (AD0LJST = 1) VREF x 4095/4096 VREF x 2048/4096 VREF x 2047/4096 0 0x0FFF 0x0800 0x07FF 0x0000 0xFFF0 0x8000 0x7FF0 0x0000 When the ADC0 Repeat Count is greater than 1, the output conversion code represents the accumulated result of the conversions performed and is updated after the last conversion in the series is finished. Sets of 4, 8, or 16 consecutive samples can be accumulated and represented in unsigned integer format. The repeat count can be selected using the AD0RPT bits in the ADC0CF register. The value must be right-justified (AD0LJST = “0”), and unused bits in the ADC0H and ADC0L registers are set to '0'. The following example shows right-justified codes for repeat counts greater than 1. Notice that accumulating 2n samples is equivalent to left-shifting by n bit positions when all samples returned from the ADC have the same value. Input Voltage Repeat Count = 4 Repeat Count = 8 Repeat Count = 16 VREF x 4095/4096 VREF x 2048/4096 VREF x 2047/4096 0 0x3FFC 0x2000 0x1FFC 0x0000 0x7FF8 0x4000 0x3FF8 0x0000 0xFFF0 0x8000 0x7FF0 0x0000 59 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 4.3.6. Settling Time Requirements A minimum tracking time is required before an accurate conversion can be performed. This tracking time is determined by the AMUX0 resistance, the ADC0 sampling capacitance, any external source resistance, and the accuracy required for the conversion. Figure 4.6 shows the equivalent ADC0 input circuit. The required ADC0 settling time for a given settling accuracy (SA) may be approximated by Equation 4.1. When measuring the Temperature Sensor output, use the settling time specified in Table 2.3 on page 28. See Table 2.3 on page 28 for ADC0 minimum settling time requirements. n 2 t = ln  ------- × R TOTAL C SAMPLE  SA Equation 4.1. ADC0 Settling Time Requirements Where: SA is the settling accuracy, given as a fraction of an LSB (for example, 0.25 to settle within 1/4 LSB) t is the required settling time in seconds RTOTAL is the sum of the AMUX0 resistance and any external source resistance. n is the ADC resolution in bits (12). M U X S elect Px.x R MUX C S A M P LE R C Inp u t = R M U X * C S A M P L E Figure 4.6. ADC0 Equivalent Input Circuits 4.4. Selectable Gain ADC0 on the C8051F52x/52xA/53x/53xA family of devices implements a selectable gain adjustment option. By writing a value to the gain adjust address range, the user can select gain values between 0 and 1.016. For example, three analog sources to be measured have full-scale outputs of 5.0 V, 4.0 V, and 3.0 V, respectively. Each ADC measurement would ideally use the full dynamic range of the ADC with an internal voltage reference of 1.5 V or 2.2 V (set to 2.2 V for this example). When selecting signal one (5.0 V fullscale), a gain value of 0.44 (5 V full scale * 0.44 = 2.2 V full scale) provides a full-scale signal of 2.2 V when the input signal is 5.0 V. Likewise, a gain value of 0.55 (4 V full scale * 0.55 = 2.2 V full scale) for the second source and 0.73 (3 V full scale * 0.73 = 2.2 V full scale) for the third source provide full-scale ADC0 measurements when the input signal is full-scale. Additionally, some sensors or other input sources have small part-to-part variations that must be accounted for to achieve accurate results. In this case, the programmable gain value could be used as a calibration value to eliminate these part-to-part variations. Rev. 1.4 60 C8051F52x/F52xA/F53x/F53xA 4.4.1. Calculating the Gain Value The ADC0 selectable gain feature is controlled by 13 bits in three registers. ADC0GNH contains the 8 upper bits of the gain value and ADC0GNL contains the 4 lower bits of the gain value. The final GAINADD bit (ADC0GNA.0) controls an optional extra 1/64 (0.016) of gain that can be added in addition to the ADC0GNH and ADC0GNL gain. The ADC0GNA.0 bit is set to 1 after a power-on reset. The equivalent gain for the ADC0GNH, ADC0GNL and ADC0GNA registers is: GAIN 1 gain =  --------------- + GAINADD ×  ------  4096   64 Equation 4.2. Equivalent Gain from the ADC0GNH and ADC0GNL Registers Where: GAIN is the 12-bit word of ADC0GNH[7:0] and ADC0GNL[7:4] GAINADD is the value of the GAINADD bit (ADC0GNA.0) gain is the equivalent gain value from 0 to 1.016 For example, if ADC0GNH = 0xFC, ADC0GNL = 0x00, and GAINADD = '1', GAIN = 0xFC0 = 4032, and the resulting equation is: 4032 1 gain =  ------------ + 1 ×  ------ = 0.984 + 0.016 = 1.0  4096  64 The table below equates values in the ADC0GNH, ADC0GNL, and ADC0GNA registers to the equivalent gain using this equation. ADC0GNH Value ADC0GNL Value GAINADD Value GAIN Value Equivalent Gain 0xFC (default) 0x00 (default) 1 (default) 4032 + 64 1.0 (default) 0x7C 0x00 1 1984 + 64 0.5 0xBC 0x00 1 3008 + 64 0.75 0x3C 0x00 1 960 + 64 0.25 0xFF 0xF0 0 4095 + 0 ~1.0 0xFF 0xF0 1 4095 + 64 1.016 For any desired gain value, the GAIN registers can be calculated by: 1 GAIN =  gain – GAINADD ×  ------  × 4096   64  Equation 4.3. Calculating the ADC0GNH and ADC0GNL Values from the Desired Gain Where: GAIN is the 12-bit word of ADC0GNH[7:0] and ADC0GNL[7:4] GAINADD is the value of the GAINADD bit (ADC0GNA.0) gain is the equivalent gain value from 0 to 1.016 When calculating the value of GAIN to load into the ADC0GNH and ADC0GNL registers, the GAINADD bit can be turned on or off to reach a value closer to the desired gain value. 61 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA For example, the initial example in this section requires a gain of 0.44 to convert 5 V full scale to 2.2 V full scale. Using Equation 4.3: 1 GAIN =  0.44 – GAINADD ×  ------  × 4096 64 If GAINADD is set to 1, this makes the equation: 1 GAIN =  0.44 – 1 ×  ------  × 4096 = 0.424 × 4096 = 1738 = 0x06CA 64 The actual gain from setting GAINADD to 1 and ADC0GNH and ADC0GNL to 0x6CA is 0.4399. A similar gain can be achieved if GAINADD is set to 0 with a different value for ADC0GNH and ADC0GNL. 4.4.2. Setting the Gain Value The three programmable gain registers are accessed indirectly using the ADC0H and ADC0L registers when the GAINEN bit (ADC0CF.0) bit is set. ADC0H acts as the address register, and ADC0L is the data register. The programmable gain registers can only be written to and cannot be read. See Gain Register Definition 4.1, Gain Register Definition 4.2, and Gain Register Definition 4.3 for more information. The gain is programmed using the following steps: 1. Set the GAINEN bit (ADC0CF.0) 2. Load the ADC0H with the ADC0GNH, ADC0GNL, or ADC0GNA address. 3. Load ADC0L with the desired value for the selected gain register. 4. Reset the GAINEN bit (ADC0CF.0) Notes: 1. An ADC conversion should not be performed while the GAINEN bit is set. 2. Even with gain enabled, the maximum input voltage must be less than VREGIN and the maximum voltage of the signal after gain must be less than or equal to VREF. In code, changing the value to 0.44 gain from the previous example looks like: // in ‘C’: ADC0CF |= 0x01;// GAINEN = 1 ADC0H = 0x04;// Load the ADC0GNH address ADC0L = 0x6C;// Load the upper byte of 0x6CA to ADC0GNH ADC0H = 0x07;// Load the ADC0GNL address ADC0L = 0xA0;// Load the lower nibble of 0x6CA to ADC0GNL ADC0H = 0x08;// Load the ADC0GNA address ADC0L = 0x01;// Set the GAINADD bit ADC0CF &= ~0x01;// GAINEN = 0 ; in assembly ORL ADC0CF,#01H ; GAINEN = 1 MOV ADC0H,#04H; Load the ADC0GNH address MOV ADC0L,#06CH ; Load the upper byte of 0x6CA to ADC0GNH MOV ADC0H,#07H; Load the ADC0GNL address MOV ADC0L,#0A0H ; Load the lower nibble of 0x6CA to ADC0GNL MOV ADC0H,#08H; Load the ADC0GNA address MOV ADC0L,#01H ; Set the GAINADD bit ANL ADC0CF,#0FEH ; GAINEN = 0 Rev. 1.4 62 C8051F52x/F52xA/F53x/F53xA Gain Register Definition 4.1. ADC0GNH: ADC0 Selectable Gain High Byte R/W R/W R/W R/W Bit7 Bit6 Bit5 Bit4 R/W R/W R/W R/W Bit2 Bit1 Bit0 GAINH[7:0] Bit3 Reset Value 11111100 Address: 0x04 Bits7–0: High byte of Selectable Gain Word. Gain Register Definition 4.2. ADC0GNL: ADC0 Selectable Gain Low Byte R/W R/W R/W R/W GAINL[3:0] Bit7 Bit6 Bit5 R/W R/W R/W R/W Reset Value Reserved Reserved Reserved Reserved 00000000 Bit4 Bit3 Bit2 Bit1 Bit0 Address: 0x07 Bits7–4: Lower 4 bits of the Selectable Gain Word. Bits3–0: Reserved. Must Write 0000b. Gain Register Definition 4.3. ADC0GNA: ADC0 Additional Selectable Gain R/W R/W R/W R/W R/W R/W R/W R/W Reset Value Reserved Reserved Reserved Reserved Reserved Reserved Reserved GAINADD 00000001 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Address: 0x08 Bits7–1: Reserved. Must Write 0000000b. Bit0: GAINADD: Additional Gain Bit. Setting this bit adds 1/64 (0.016) gain to the gain value in the ADC0GNH and ADC0GNL registers. 63 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 4.4. ADC0MX: ADC0 Channel Select R/W R/W R/W - - - Bit7 Bit6 Bit5 R/W R/W R/W R/W R/W Reset Value Bit1 Bit0 SFR Address: AD0MX Bit4 Bit3 Bit2 00011111 0xBB Bits7–5: UNUSED. Read = 000b; Write = don’t care. Bits4–0: AD0MX4–0: AMUX0 Positive Input Selection AD0MX4–0 ADC0 Input Channel 00000 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010 01011 01100 01101 01110 01111 11000 11001 11010 - 11111 P0.0 P0.1 P0.2 P0.3 P0.4 P0.5 P0.6* P0.7* P1.0* P1.1* P1.2* P1.3* P1.4* P1.5* P1.6* P1.7* Temp Sensor VDD GND Note: Only applies to C8051F53x/C8051F53xA parts. Rev. 1.4 64 C8051F52x/F52xA/F53x/F53xA SFR Definition 4.5. ADC0CF: ADC0 Configuration R/W R/W R/W R/W R/W AD0SC Bit7 Bit6 Bit5 R/W R/W AD0RPT Bit4 Bit3 Bit2 Bit1 R/W Reset Value GAINEN 11111000 Bit0 SFR Address: 0xBC Bits7–3: AD0SC4–0: ADC0 SAR Conversion Clock Period Bits. SAR Conversion clock is derived from FCLK by the following equation, where AD0SC refers to the 5-bit value held in bits AD0SC4–0. SAR Conversion clock requirements are given in Table 2.3 on page 28. BURSTEN = 0: FCLK is the current system clock. BURSTEN = 1: FCLK is the Burst Mode Oscillator, specified in Table 2.3. FCLK AD0SC = -------------------- – 1 * CLK SAR or FCLK CLK SAR = ---------------------------AD0SC + 1 Note: Round the result up. Bits2–1: AD0RPT1–0: ADC0 Repeat Count. Controls the number of conversions taken and accumulated between ADC0 End of Conversion (ADCINT) and ADC0 Window Comparator (ADCWINT) interrupts. A convert start is required for each conversion unless Burst Mode is enabled. In Burst Mode, a single convert start can initiate multiple self-timed conversions. Results in both modes are accumulated in the ADC0H:ADC0L register. When AD0RPT1–0 are set to a value other than '00', the AD0LJST bit in the ADC0CN register must be set to '0' (right justified). 00: 1 conversion is performed. 01: 4 conversions are performed and accumulated. 10: 8 conversions are performed and accumulated. 11: 16 conversions are performed and accumulated. Bit0: 65 GAINEN: Gain Enable Bit. Controls the gain programming. For more information of the usage, refer to the following chapter: Section “4.4. Selectable Gain” on page 60. Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 4.6. ADC0H: ADC0 Data Word MSB R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xBE Bits7–0: ADC0 Data Word High-Order Bits. For AD0LJST = 0 and AD0RPT as follows: 00: Bits 3–0 are the upper 4 bits of the 12-bit result. Bits 7–4 are 0000b. 01: Bits 4–0 are the upper 5 bits of the 14-bit result. Bits 7–5 are 000b. 10: Bits 5–0 are the upper 6 bits of the 15-bit result. Bits 7–6 are 00b. 11: Bits 7–0 are the upper 8 bits of the 16-bit result. For AD0LJST = 1 (AD0RPT must be '00'): Bits 7–0 are the most-significant bits of the ADC0 12-bit result. SFR Definition 4.7. ADC0L: ADC0 Data Word LSB R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xBD Bits7–0: ADC0 Data Word Low-Order Bits. For AD0LJST = 0: Bits 7–0 are the lower 8 bits of the ADC0 Accumulated Result. For AD0LJST = 1 (AD0RPT must be '00'): Bits 7–4 are the lower 4 bits of the 12-bit result. Bits 3–0 are 0000b. Rev. 1.4 66 C8051F52x/F52xA/F53x/F53xA SFR Definition 4.8. ADC0CN: ADC0 Control R/W R/W R/W R/W R/W R/W R/W R/W AD0EN BURSTEN AD0INT AD0BUSY AD0WINT AD0LJST AD0CM1 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 (bit addressable) Bit7: Reset Value AD0CM0 00000000 SFR Address: 0xE8 AD0EN: ADC0 Enable Bit. 0: ADC0 Disabled. ADC0 is in low-power shutdown. 1: ADC0 Enabled. ADC0 is active and ready for data conversions. Bit6: BURSTEN: ADC0 Burst Mode Enable Bit. 0: ADC0 Burst Mode Disabled. 1: ADC0 Burst Mode Enabled. Bit5: AD0INT: ADC0 Conversion Complete Interrupt Flag. 0: ADC0 has not completed a data conversion since the last time AD0INT was cleared. 1: ADC0 has completed a data conversion. Bit4: AD0BUSY: ADC0 Busy Bit. Read: 0: ADC0 conversion is complete or a conversion is not currently in progress. AD0INT is set to logic 1 on the falling edge of AD0BUSY. 1: ADC0 conversion is in progress. Write: 0: No Effect. 1: Initiates ADC0 Conversion if AD0CM1–0 = 00b Bit3: AD0WINT: ADC0 Window Compare Interrupt Flag. This bit must be cleared by software. 0: ADC0 Window Comparison Data match has not occurred since this flag was last cleared. 1: ADC0 Window Comparison Data match has occurred. Bit2: AD0LJST: ADC0 Left Justify Select 0: Data in ADC0H:ADC0L registers is right justified. 1: Data in ADC0H:ADC0L registers is left justified. This option should not be used with a repeat count greater than 1 (when AD0RPT1–0 is 01b, 10b, or 11b). Bits1–0: AD0CM1–0: ADC0 Start of Conversion Mode Select. 00: ADC0 conversion initiated on every write of 1 to AD0BUSY. 01: ADC0 conversion initiated on overflow of Timer 1. 10: ADC0 conversion initiated on rising edge of external CNVSTR. 11: ADC0 conversion initiated on overflow of Timer 2. 67 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 4.9. ADC0TK: ADC0 Tracking Mode Select R/W R/W R/W R/W R/W AD0PWR Bit7 Bit6 Bit5 R/W R/W AD0TM Bit4 Bit3 R/W Reset Value Bit0 SFR Address: AD0TK Bit2 Bit1 11111111 (bit addressable) 0xBA Bits7–4: AD0PWR3–0: ADC0 Burst Power-Up Time. For BURSTEN = 0: ADC0 power state controlled by AD0EN. For BURSTEN = 1 and AD0EN = 1; ADC0 remains enabled and does not enter the very low power state. For BURSTEN = 1 and AD0EN = 0: ADC0 enters the very low power state as specified in Table 2.3 on page 28 and is enabled after each convert start signal. The Power Up time is programmed according to the following equation: Tstartup AD0PWR = ---------------------- – 1 200ns or Tstartup = ( AD0PWR + 1 )200ns Bits3–2: AD0TM1–0: ADC0 Tracking Mode Select Bits. 00: Reserved. 01: ADC0 is configured to Post-Tracking Mode. 10: ADC0 is configured to Pre-Tracking Mode. 11: ADC0 is configured to Dual-Tracking Mode (default). Bits1–0: AD0TK1–0: ADC0 Post-Track Time. Post-Tracking time is controlled by AD0TK as follows: 00: Post-Tracking time is equal to 2 SAR clock cycles + 2 FCLK cycles. 01: Post-Tracking time is equal to 4 SAR clock cycles + 2 FCLK cycles. 10: Post-Tracking time is equal to 8 SAR clock cycles + 2 FCLK cycles. 11: Post-Tracking time is equal to 16 SAR clock cycles + 2 FCLK cycles. Rev. 1.4 68 C8051F52x/F52xA/F53x/F53xA 4.5. Programmable Window Detector The ADC Programmable Window Detector continuously compares the ADC0 output registers to user-programmed limits, and notifies the system when a desired condition is detected. This is especially effective in an interrupt-driven system, saving code space and CPU bandwidth while delivering faster system response times. The window detector interrupt flag (AD0WINT in register ADC0CN) can also be used in polled mode. The ADC0 Greater-Than (ADC0GTH, ADC0GTL) and Less-Than (ADC0LTH, ADC0LTL) registers hold the comparison values. The window detector flag can be programmed to indicate when measured data is inside or outside of the user-programmed limits, depending on the contents of the ADC0 Less-Than and ADC0 Greater-Than registers. SFR Definition 4.10. ADC0GTH: ADC0 Greater-Than Data High Byte R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 11111111 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xC4 Bits7–0: High byte of ADC0 Greater-Than Data Word. SFR Definition 4.11. ADC0GTL: ADC0 Greater-Than Data Low Byte R/W R/W R/W R/W R/W R/W R/W R/W Reset Value Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 11111111 0xC3 Bits7–0: Low byte of ADC0 Greater-Than Data Word. 69 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 4.12. ADC0LTH: ADC0 Less-Than Data High Byte R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xC6 Bits7–0: High byte of ADC0 Less-Than Data Word. SFR Definition 4.13. ADC0LTL: ADC0 Less-Than Data Low Byte R/W R/W R/W R/W R/W R/W R/W R/W Reset Value Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 00000000 0xC5 Bits7–0: Low byte of ADC0 Less-Than Data Word. Rev. 1.4 70 C8051F52x/F52xA/F53x/F53xA 4.5.1. Window Detector In Single-Ended Mode Figure 4.7 shows two example window comparisons for right-justified data with ADC0LTH:ADC0LTL = 0x0200 (512d) and ADC0GTH:ADC0GTL = 0x0100 (256d). The input voltage can range from 0 to VREF x (4095/4096) with respect to GND, and is represented by a 12-bit unsigned integer value. The repeat count is set to one. In the left example, an AD0WINT interrupt will be generated if the ADC0 conversion word (ADC0H:ADC0L) is within the range defined by ADC0GTH:ADC0GTL and ADC0LTH:ADC0LTL (if 0x0100 < ADC0H:ADC0L < 0x0200). In the right example, and AD0WINT interrupt will be generated if the ADC0 conversion word is outside of the range defined by the ADC0GT and ADC0LT registers (if ADC0H:ADC0L < 0x0100 or ADC0H:ADC0L > 0x0200). Figure 4.8 shows an example using left-justified data with the same comparison values. ADC0H:ADC0L ADC0H:ADC0L Input Voltage (Px.x - GND) VREF x (4095/4096) Input Voltage (Px.x - GND) VREF x (4095/ 4096) 0x0FFF 0x0FFF AD0WINT not affected AD0WINT=1 0x0201 VREF x (512/4096) 0x0200 0x01FF 0x0201 ADC0LTH:ADC0LTL VREF x (512/4096) 0x0200 0x01FF AD0WINT=1 0x0101 VREF x (256/4096) 0x0100 0x0101 ADC0GTH:ADC0GTL VREF x (256/4096) 0x00FF 0x0100 AD0WINT not affected ADC0LTH:ADC0LTL 0x00FF AD0WINT=1 AD0WINT not affected 0 ADC0GTH:ADC0GTL 0x0000 0x0000 0 Figure 4.7. ADC Window Compare Example: Right-Justified Single-Ended Data ADC0H:ADC0L ADC0H:ADC0L Input Voltage (Px.x - GND) VREF x (4095/4096) Input Voltage (Px.x - GND) 0xFFF0 VREF x (4095/4096) 0xFFF0 AD0WINT not affected AD0WINT=1 0x2010 VREF x (512/4096) 0x2000 0x2010 ADC0LTH:ADC0LTL VREF x (512/4096) 0x1FF0 0x2000 0x1FF0 AD0WINT=1 0x1010 VREF x (256/4096) 0x1000 0x1010 ADC0GTH:ADC0GTL VREF x (256/4096) 0x0FF0 0x1000 AD0WINT not affected ADC0LTH:ADC0LTL 0x0FF0 AD0WINT=1 AD0WINT not affected 0 ADC0GTH:ADC0GTL 0x0000 0 0x0000 Figure 4.8. ADC Window Compare Example: Left-Justified Single-Ended Data 71 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 5. Voltage Reference The Voltage reference MUX on C8051F52x/F52xA/F53x/F53xA devices is configurable to use an externally connected voltage reference, the internal reference voltage generator, or the VDD power supply voltage (see Figure 5.1). The REFSL bit in the Reference Control register (REF0CN) selects the reference source. For an external source or the internal reference applied to the VREF pin, REFSL should be set to 0. To use VDD as the reference source, REFSL should be set to 1. The BIASE bit enables the internal voltage bias generator, which is used by the ADC, Temperature Sensor, and internal oscillators. This bit is forced to logic 1 when any of the aforementioned peripherals are enabled. The bias generator may be enabled manually by writing a 1 to the BIASE bit in register REF0CN; see SFR Definition 5.1 for REF0CN register details. The electrical specifications for the voltage reference circuit are given in Table 2.5 on page 29. The internal voltage reference circuit consists of a temperature stable bandgap voltage reference generator and a gain-of-two output buffer amplifier. The output voltage is selectable between 1.5 V and 2.2 V. The internal voltage reference can be driven out on the VREF pin by setting the REFBE bit in register REF0CN to a 1 (see Figure 5.1). The load seen by the VREF pin must draw less than 200 µA to GND. When using the internal voltage reference, bypass capacitors of 0.1 µF and 4.7 µF are recommended from the VREF pin to GND. If the internal reference is not used, the REFBE bit should be cleared to 0. Electrical specifications for the internal voltage reference are given in Table 2.5 on page 29. REFLV REFSL TEMPE BIASE REFBE REF0CN EN Bias Generator To ADC, Internal Oscillators IOSCEN VDD R1 External Voltage Reference Circuit EN VREF Temp Sensor To Analog Mux 0 VREF (to ADC) GND VDD 1 REFBE EN Internal Reference REFLV Figure 5.1. Voltage Reference Functional Block Diagram Rev. 1.4 72 C8051F52x/F52xA/F53x/F53xA Important Note About the VREF Pin: Port pin P0.0 is used as the external VREF input and as an output for the internal VREF. When using either an external voltage reference or the internal reference circuitry, P0.0 should be configured as an analog pin, and skipped by the Digital Crossbar. To configure P0.0 as an analog pin, clear Bit 0 in register P0MDIN to 0. To configure the Crossbar to skip P0.0, set Bit 0 in register P0SKIP to 1. Refer to Section “13. Port Input/Output” on page 120 for complete Port I/O configuration details. The TEMPE bit in register REF0CN enables/disables the temperature sensor. While disabled, the temperature sensor defaults to a high impedance state and any ADC0 measurements performed on the sensor result in meaningless data. SFR Definition 5.1. REF0CN: Reference Control R/W R/W Reserved Reserved Bit7 Bit6 R/W R/W R/W R/W R/W R/W Reset Value ZTCEN REFLV REFSL TEMPE BIASE REFBE 00000000 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xD1 Bits7–6: RESERVED. Read = 00b. Must write 00b. Bit5: ZTCEN: Zero-TempCo Bias Enable Bit*. 0: ZeroTC Bias Generator automatically enabled when needed. 1: ZeroTC Bias Generator forced on. Bit4: REFLV: Voltage Reference Output Level Select. This bit selects the output voltage level for the internal voltage reference. 0: Internal voltage reference set to 1.5 V. 1: Internal voltage reference set to 2.2 V. Bit3: REFSL: Voltage Reference Select. This bit selects the source for the internal voltage reference. 0: VREF pin used as voltage reference. 1: VDD used as voltage reference. Bit2: TEMPE: Temperature Sensor Enable Bit. 0: Internal Temperature Sensor off. 1: Internal Temperature Sensor on. Bit1: BIASE: Internal Analog Bias Generator Enable Bit. 0: Internal Analog Bias Generator automatically enabled when needed. 1: Internal Analog Bias Generator on. Bit0: REFBE: Internal Reference Buffer Enable Bit. 0: Internal Reference Buffer disabled. 1: Internal Reference Buffer enabled. Internal voltage reference driven on the VREF pin. *Note: See Section “20.7. Internal Oscillator Suspend Mode” on page 212 for a note related to the ZTCEN bit in older silicon revisions. 73 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 6. Voltage Regulator (REG0) C8051F52x/F52xA/F53x/F53xAdevices include an on-chip low dropout voltage regulator (REG0). The input to REG0 at the VREGIN pin can be as high as 5.25 V. The output can be selected by software to 2.1 V or 2.6 V. When enabled, the output of REG0 appears on the VDD pin, powers the microcontroller core, and can be used to power external devices. On reset, REG0 is enabled and can be disabled by software. The input (VREGIN) and output (VDD) of the voltage regulator should both be bypassed with a large capacitor (4.7 µF + 0.1 µF) to ground. These capacitors are required for regulator stability, and will eliminate power spikes and provide any immediate power required by the microcontroller. The settling time associated with the voltage regulator is shown in Table 2.6 on page 30. Important Note: The bypass capacitors are required for the stability of the voltage regulator. The voltage regulator can also generate an interrupt (if enabled by EREG0, EIE1.6) that is triggered whenever the VREGIN input voltage drops below the dropout threshold (see Table 2.6 on page 30). This dropout interrupt has no pending flag. The recommended procedure to use the interrupt is as follows: 1. Wait enough time to ensure the VREGIN input voltage is stable. 2. Enable the dropout interrupt (EREG0, EIE1.6) and select the proper priority (PREG0, EIP1.6). 3. If triggered, disable the interrupt in the Interrupt Service Routine (clear EREG0, EIE1.6) and execute all necessary procedures to put the system in “safe mode,” leaving the interrupt disabled. 4. The main application, now running in safe mode, should regularly check the DROPOUT bit (REG0CN.0). Once it is cleared by the regulator hardware, the application can re-enable the interrupt (EREG0, EIE1.6) and return to normal mode operation. VREGIN REG0 4.7 µF .1 µF VDD VDD 4.7 µF .1 µF Figure 6.1. External Capacitors for Voltage Regulator Input/Output Rev. 1.4 74 C8051F52x/F52xA/F53x/F53xA SFR Definition 6.1. REG0CN: Regulator Control R/W R/W REGDIS Reserved Bit7 Bit6 R R/W R R R — REG0MD — — — Bit5 Bit4 Bit3 Bit2 Bit1 R Bit0 SFR Address: Bit7: REGDIS: Voltage Regulator Disable Bit. This bit disables/enables the Voltage Regulator. 0: Voltage Regulator Enabled. 1: Voltage Regulator Disabled. Bit6: RESERVED. Read = 1b. Must write 1b. Bit5: UNUSED. Read = 0b. Write = don’t care. Bit4: REG0MD: Voltage Regulator Mode Select Bit. This bit selects the Voltage Regulator output voltage. 0: Voltage Regulator output is 2.1 V. 1: Voltage Regulator output is 2.6 V (default). Bits3–1: UNUSED. Read = 000b. Write = don’t care. Bit0: DROPOUT: Voltage Regulator Dropout Indicator Bit. 0: Voltage Regulator is not in dropout. 1: Voltage Regulator is in or near dropout. 75 Rev. 1.4 Reset Value DROPOUT 01010000 0xC9 C8051F52x/F52xA/F53x/F53xA 7. Comparator C8051F52x/F52xA/F53x/F53xA devices include one on-chip programmable voltage comparator. The Comparator is shown in Figure 7.1. The Comparator offers programmable response time and hysteresis, an analog input multiplexer, and two outputs that are optionally available at the Port pins: a synchronous “latched” output (CP0), or an asynchronous “raw” output (CP0A). The asynchronous CP0A signal is available even when the system clock is not active. This allows the Comparator to operate and generate an output with the device in STOP or SUSPEND mode. When assigned to a Port pin, the Comparator output may be configured as open drain or push-pull (see Section “13.2. Port I/O Initialization” on page 126). The Comparator may also be used as a reset source (see Section “11.5. Comparator Reset” on page 110). The Comparator inputs are selected in the CPT0MX register (SFR Definition 7.2). The CMX0P3–CMX0P0 bits select the Comparator0 positive input; the CMX0N3–CMX0N0 bits select the Comparator0 negative input. CPT0CN Important Note About Comparator Inputs: The Port pins selected as Comparator inputs should be configured as analog inputs in their associated Port configuration register and configured to be skipped by the Crossbar (for details on Port configuration, see Section “13.3. General Purpose Port I/O” on page 128). CPT0MX CMX0N3 CMX0N2 CMX0N1 CMX0N0 CMX0P3 CP0EN CP0OUT CP0RIF VDD CP0FIF CP0HYP1 CP0HYP0 CP0 Interrupt CP0HYN1 CP0HYN0 CMX0P2 CMX0P1 CMX0P0 CP0 Rising-edge P0.0 CP0 Falling-edge P0.2 P0.1 P0.4 CP0 + Interrupt Logic P0.3 P0.6* P0.5 CP0 + P1.0* P0.7* D P1.2* - SET CLR Q Q D SET CLR Q Q P1.1* Crossbar P1.4* (SYNCHRONIZER) P1.3* GND P1.6* P1.5* CP0 - CP0A Reset Decision Tree P1.7* *Available in parts 'F53x/'F53xA CPT0MD CP0RIE CP0FIE CP0MD1 CP0MD0 Figure 7.1. Comparator Functional Block Diagram The Comparator output can be polled in software, used as an interrupt source, internal oscillator suspend awakening source and/or routed to a Port pin. When routed to a Port pin, the Comparator output is available asynchronous or synchronous to the system clock; the asynchronous output is available even in STOP or SUSPEND mode (with no system clock active). When disabled, the Comparator output (if assigned to a Port I/O pin via the Crossbar) defaults to the logic low state, and its supply current falls to Rev. 1.4 76 C8051F52x/F52xA/F53x/F53xA less than 100 nA. See Section “13.1. Priority Crossbar Decoder” on page 122 for details on configuring Comparator outputs via the digital Crossbar. Comparator inputs can be externally driven from –0.25 V to (VREGIN) + 0.25 V without damage or upset. The complete Comparator electrical specifications are given in Table 2.7 on page 31. The Comparator response time may be configured in software via the CPTnMD register (see SFR Definition 7.3). Selecting a longer response time reduces the Comparator supply current. See Table 2.7 on page 31 for complete timing and current consumption specifications. VIN+ VIN- CP0+ CP0- + CP0 _ OUT CIRCUIT CONFIGURATION Positive Hysteresis Voltage (Programmed with CP0HYP Bits) VIN- INPUTS Negative Hysteresis Voltage (Programmed by CP0HYN Bits) VIN+ VOH OUTPUT VOL Negative Hysteresis Disabled Positive Hysteresis Disabled Maximum Negative Hysteresis Maximum Positive Hysteresis Figure 7.2. Comparator Hysteresis Plot The Comparator hysteresis is software-programmable via its Comparator Control register CPT0CN. The user can program both the amount of hysteresis voltage (referred to the input voltage) and the positive and negative-going symmetry of this hysteresis around the threshold voltage. The Comparator hysteresis is programmed using Bits3–0 in the Comparator Control Register CPT0CN (shown in SFR Definition 7.1). The amount of negative hysteresis voltage is determined by the settings of the CP0HYN bits. As shown in Table 2.7 on page 31, settings of 20, 10 or 5 mV of negative hysteresis can be programmed, or negative hysteresis can be disabled. In a similar way, the amount of positive hysteresis is determined by the setting the CP0HYP bits. Comparator interrupts can be generated on both rising-edge and falling-edge output transitions. (For Interrupt enable and priority control, see Section “10. Interrupt Handler” on page 98). The CP0FIF flag is set to logic 1 upon a Comparator falling-edge detect, and the CP0RIF flag is set to logic 1 upon the Comparator rising-edge detect. Once set, these bits remain set until cleared by software. The output state of the Comparator can be obtained at any time by reading the CP0OUT bit. The Comparator is enabled by setting the CP0EN bit to logic 1 and is disabled by clearing this bit to logic 0. When the Comparator is enabled, the internal oscillator is awakened from SUSPEND mode if the Comparator output is logic 0. 77 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Note that false rising edges and falling edges can be detected when the comparator is first powered-on or if changes are made to the hysteresis or response time control bits. Therefore, it is recommended that the rising-edge and falling-edge flags be explicitly cleared to logic 0 a short time after the comparator is enabled or its mode bits have been changed. This Power Up Time is specified in Table 2.7 on page 31. SFR Definition 7.1. CPT0CN: Comparator0 Control R/W R R/W R/W CP0EN CP0OUT CP0RIF CP0FIF Bit7 Bit6 Bit5 Bit4 R/W R/W R/W R/W Reset Value CP0HYP1 CP0HYP0 CP0HYN1 CP0HYN0 00000000 Bit3 Bit2 Bit1 Bit0 SFR Address: 0x9B Bit7: CP0EN: Comparator0 Enable Bit. 0: Comparator0 Disabled. 1: Comparator0 Enabled. Bit6: CP0OUT: Comparator0 Output State Flag. 0: Voltage on CP0+ < CP0–. 1: Voltage on CP0+ > CP0–. Bit5: CP0RIF: Comparator0 Rising-Edge Flag. 0: No Comparator0 Rising Edge has occurred since this flag was last cleared. 1: Comparator0 Rising Edge has occurred. Bit4: CP0FIF: Comparator0 Falling-Edge Flag. 0: No Comparator0 Falling-Edge has occurred since this flag was last cleared. 1: Comparator0 Falling-Edge has occurred. Bits3–2: CP0HYP1–0: Comparator0 Positive Hysteresis Control Bits. 00: Positive Hysteresis Disabled. 01: Positive Hysteresis = 5 mV. 10: Positive Hysteresis = 10 mV. 11: Positive Hysteresis = 20 mV. Bits1–0: CP0HYN1–0: Comparator0 Negative Hysteresis Control Bits. 00: Negative Hysteresis Disabled. 01: Negative Hysteresis = 5 mV. 10: Negative Hysteresis = 10 mV. 11: Negative Hysteresis = 20 mV. Rev. 1.4 78 C8051F52x/F52xA/F53x/F53xA SFR Definition 7.2. CPT0MX: Comparator0 MUX Selection R/W R/W R/W R/W R/W R/W CMX0N3 CMX0N2 CMX0N1 CMX0N0 CMX0P3 CMX0P2 Bit7 Bit6 Bit5 Bit4 Bit3 R/W R/W CMX0P1 CMX0P0 01110111 Bit1 Bit0 SFR Address: Bit2 Reset Value 0x9F Bits7–4: CMX0N3–CMX0N0: Comparator0 Negative Input MUX Select. These bits select which Port pin is used as the Comparator0 negative input. CMX0N3 CMX0N2 CMX0N1 CMX0N0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 Negative Input P0.1 P0.3 P0.5 P0.7* P1.1* P1.3* P1.5* P1.7* *Note: Available only on the C8051F53x/53xA devices Bits1–0: CMX0P3–CMX0P0: Comparator0 Positive Input MUX Select. These bits select which Port pin is used as the Comparator0 positive input. CMX0P3 CMX0P2 CMX0P1 CMX0P0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 *Note: Available only on the C8051F53x/53xA devices. 79 Rev. 1.4 Positive Input P0.0 P0.2 P0.4 P0.6* P1.0* P1.2* P1.4* P1.6* C8051F52x/F52xA/F53x/F53xA SFR Definition 7.3. CPT0MD: Comparator0 Mode Selection R/W R/W R/W R/W R/W R/W Reserved — CP0RIE CP0FIE — — Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 R/W R/W Reset Value CP0MD1 CP0MD0 00000010 Bit1 Bit0 SFR Address: 0x9D Bit7: Bit6: Bit5: RESERVED. Read = 0b. Must write 0b. UNUSED. Read = 0b. Write = don’t care. CP0RIE: Comparator Rising-Edge Interrupt Enable. 0: Comparator rising-edge interrupt disabled. 1: Comparator rising-edge interrupt enabled. Bit4: CP0FIE: Comparator Falling-Edge Interrupt Enable. 0: Comparator falling-edge interrupt disabled. 1: Comparator falling-edge interrupt enabled. Note: It is necessary to enable both CP0xIE and the correspondent ECPx bit located in EIE1 SFR. Bits3–2: UNUSED. Read = 00b. Write = don’t care. Bits1–0: CP0MD1–CP0MD0: Comparator0 Mode Select These bits select the response time for Comparator0. Mode CP0MD1 CP0MD0 CP0 Falling Edge Response Time (TYP) 0 1 2 3 0 0 1 1 0 1 0 1 Fastest Response Time — — Lowest Power Consumption Note: Rising Edge response times are approximately double the Falling Edge response times. Rev. 1.4 80 C8051F52x/F52xA/F53x/F53xA 8. CIP-51 Microcontroller The MCU system controller core is the CIP-51 microcontroller. The CIP-51 is fully compatible with the MCS-51™ instruction set. Standard 803x/805x assemblers and compilers can be used to develop software. The C8051F52x/F52xA/F53x/F53xA family has a superset of all the peripherals included with a standard 8051. See Section “1. System Overview” on page 13 for more information about the available peripherals. The CIP-51 includes on-chip debug hardware which interfaces directly with the analog and digital subsystems, providing a complete data acquisition or control-system solution in a single integrated circuit. The CIP-51 Microcontroller core implements the standard 8051 organization and peripherals as well as additional custom peripherals and functions to extend its capability (see Figure 8.1 for a block diagram). The CIP-51 core includes the following features:   Fully Compatible with MCS-51 Instruction Set  25 MIPS Peak Throughput  256 Bytes of Internal RAM  Extended Interrupt Handler Reset Input  Power Management Modes  Integrated Debug Logic  Program and Data Memory Security D8 D8 ACCUMULATOR STACK POINTER TMP1 TMP2 SRAM ADDRESS REGISTER PSW SRAM (256 X 8) D8 D8 D8 ALU D8 DATA BUS B REGISTER D8 D8 D8 DATA BUS DATA BUS SFR_ADDRESS BUFFER D8 DATA POINTER D8 D8 SFR_CONTROL SFR BUS INTERFACE SFR_WRITE_DATA SFR_READ_DATA DATA BUS PC INCREMENTER PROGRAM COUNTER (PC) PRGM. ADDRESS REG. MEM_ADDRESS D8 MEM_CONTROL A16 MEMORY INTERFACE MEM_WRITE_DATA MEM_READ_DATA PIPELINE RESET D8 CONTROL LOGIC SYSTEM_IRQs CLOCK D8 STOP IDLE POWER CONTROL REGISTER INTERRUPT INTERFACE EMULATION_IRQ D8 Figure 8.1. CIP-51 Block Diagram Rev. 1.4 81 C8051F52x/F52xA/F53x/F53xA Performance The CIP-51 employs a pipelined architecture that greatly increases its instruction throughput over the standard 8051 architecture. In a standard 8051, all instructions except for MUL and DIV take 12 or 24 system clock cycles to execute, and usually have a maximum system clock of 12 MHz. By contrast, the CIP-51 core executes 70% of its instructions in one or two system clock cycles, with no instructions taking more than eight system clock cycles. With the CIP-51's system clock running at 25 MHz, it has a peak throughput of 25 MIPS. The CIP-51 has a total of 109 instructions. The table below shows the total number of instructions that require each execution time. Clocks to Execute 1 2 2/3 3 3/4 4 4/5 5 8 Number of Instructions 26 50 5 14 7 3 1 2 1 Programming and Debugging Support In-system programming of the Flash program memory and communication with on-chip debug support logic is accomplished via the Silicon Labs 2-Wire (C2) interface. Note that the re-programmable Flash can also be read and written a single byte at a time by the application software using the MOVC and MOVX instructions. This feature allows program memory to be used for non-volatile data storage as well as updating program code under software control. The on-chip debug support logic facilitates full speed in-circuit debugging, allowing the setting of hardware breakpoints, starting, stopping and single stepping through program execution (including interrupt service routines), examination of the program's call stack, and reading/writing the contents of registers and memory. This method of on-chip debugging is completely non-intrusive, requiring no RAM, Stack, timers, or other on-chip resources. The CIP-51 is supported by development tools from Silicon Laboratories, Inc. and third party vendors. Silicon Laboratories provides an integrated development environment (IDE) including editor, evaluation compiler, assembler, debugger and programmer. The IDE's debugger and programmer interface to the CIP-51 via the on-chip debug logic to provide fast and efficient in-system device programming and debugging. Third party macro assemblers and C compilers are also available. 8.1. Instruction Set The instruction set of the CIP-51 System Controller is fully compatible with the standard MCS-51™ instruction set. Standard 8051 development tools can be used to develop software for the CIP-51. All CIP-51 instructions are the binary and functional equivalent of their MCS-51™ counterparts, including opcodes, addressing modes and effect on PSW flags. However, instruction timing is different than that of the standard 8051. 8.1.1. Instruction and CPU Timing In many 8051 implementations, a distinction is made between machine cycles and clock cycles, with machine cycles varying from 2 to 12 clock cycles in length. However, the CIP-51 implementation is based solely on clock cycle timing. All instruction timings are specified in terms of clock cycles. Due to the pipelined architecture of the CIP-51, most instructions execute in the same number of clock cycles as there are program bytes in the instruction. Conditional branch instructions take one less clock cycle to complete when the branch is not taken as opposed to when the branch is taken. Table 8.1 is the CIP-51 Instruction Set Summary, which includes the mnemonic, number of bytes, and number of clock cycles for each instruction. 82 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 8.1.2. MOVX Instruction and Program Memory The MOVX instruction is typically used to access data stored in XDATA memory space. In the CIP-51, the MOVX instruction can also be used to write or erase on-chip program memory space implemented as reprogrammable Flash memory. The Flash access feature provides a mechanism for the CIP-51 to update program code and use the program memory space for non-volatile data storage. Refer to Section “12. Flash Memory” on page 113 for further details. Table 8.1. CIP-51 Instruction Set Summary Mnemonic Description Bytes Clock Cycles Arithmetic Operations ADD A, Rn ADD A, direct ADD A, @Ri ADD A, #data ADDC A, Rn ADDC A, direct ADDC A, @Ri ADDC A, #data SUBB A, Rn SUBB A, direct SUBB A, @Ri SUBB A, #data INC A INC Rn INC direct INC @Ri DEC A DEC Rn DEC direct DEC @Ri INC DPTR MUL AB DIV AB DA A Add register to A Add direct byte to A Add indirect RAM to A Add immediate to A Add register to A with carry Add direct byte to A with carry Add indirect RAM to A with carry Add immediate to A with carry Subtract register from A with borrow Subtract direct byte from A with borrow Subtract indirect RAM from A with borrow Subtract immediate from A with borrow Increment A Increment register Increment direct byte Increment indirect RAM Decrement A Decrement register Decrement direct byte Decrement indirect RAM Increment Data Pointer Multiply A and B Divide A by B Decimal adjust A 1 2 1 2 1 2 1 2 1 2 1 2 1 1 2 1 1 1 2 1 1 1 1 1 1 2 2 2 1 2 2 2 1 2 2 2 1 1 2 2 1 1 2 2 1 4 8 1 AND Register to A AND direct byte to A AND indirect RAM to A AND immediate to A AND A to direct byte AND immediate to direct byte OR Register to A OR direct byte to A OR indirect RAM to A OR immediate to A OR A to direct byte 1 2 1 2 2 3 1 2 1 2 2 1 2 2 2 2 3 1 2 2 2 2 Logical Operations ANL A, Rn ANL A, direct ANL A, @Ri ANL A, #data ANL direct, A ANL direct, #data ORL A, Rn ORL A, direct ORL A, @Ri ORL A, #data ORL direct, A Rev. 1.4 83 C8051F52x/F52xA/F53x/F53xA Table 8.1. CIP-51 Instruction Set Summary (Continued) Mnemonic ORL direct, #data XRL A, Rn XRL A, direct XRL A, @Ri XRL A, #data XRL direct, A XRL direct, #data CLR A CPL A RL A RLC A RR A RRC A SWAP A Description Bytes Clock Cycles OR immediate to direct byte Exclusive-OR Register to A Exclusive-OR direct byte to A Exclusive-OR indirect RAM to A Exclusive-OR immediate to A Exclusive-OR A to direct byte Exclusive-OR immediate to direct byte Clear A Complement A Rotate A left Rotate A left through Carry Rotate A right Rotate A right through Carry Swap nibbles of A 3 1 2 1 2 2 3 1 1 1 1 1 1 1 3 1 2 2 2 2 3 1 2 1 1 1 1 1 Move Register to A Move direct byte to A Move indirect RAM to A Move immediate to A Move A to Register Move direct byte to Register Move immediate to Register Move A to direct byte Move Register to direct byte Move direct byte to direct byte Move indirect RAM to direct byte Move immediate to direct byte Move A to indirect RAM Move direct byte to indirect RAM Move immediate to indirect RAM Load DPTR with 16-bit constant Move code byte relative DPTR to A Move code byte relative PC to A Move external data (8-bit address) to A Move A to external data (8-bit address) Move external data (16-bit address) to A Move A to external data (16-bit address) Push direct byte onto stack Pop direct byte from stack Exchange Register with A Exchange direct byte with A Exchange indirect RAM with A Exchange low nibble of indirect RAM with A 1 2 1 2 1 2 2 2 2 3 2 3 1 2 2 3 1 1 1 1 1 1 2 2 1 2 1 1 1 2 2 2 1 2 2 2 2 3 2 3 2 2 2 3 3 3 3 3 3 3 2 2 1 2 2 2 Data Transfer MOV A, Rn MOV A, direct MOV A, @Ri MOV A, #data MOV Rn, A MOV Rn, direct MOV Rn, #data MOV direct, A MOV direct, Rn MOV direct, direct MOV direct, @Ri MOV direct, #data MOV @Ri, A MOV @Ri, direct MOV @Ri, #data MOV DPTR, #data16 MOVC A, @A+DPTR MOVC A, @A+PC MOVX A, @Ri MOVX @Ri, A MOVX A, @DPTR MOVX @DPTR, A PUSH direct POP direct XCH A, Rn XCH A, direct XCH A, @Ri XCHD A, @Ri 84 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 8.1. CIP-51 Instruction Set Summary (Continued) Mnemonic Description Bytes Clock Cycles Boolean Manipulation CLR C CLR bit SETB C SETB bit CPL C CPL bit ANL C, bit ANL C, /bit ORL C, bit ORL C, /bit MOV C, bit MOV bit, C JC rel JNC rel JB bit, rel JNB bit, rel JBC bit, rel Clear Carry Clear direct bit Set Carry Set direct bit Complement Carry Complement direct bit AND direct bit to Carry AND complement of direct bit to Carry OR direct bit to carry OR complement of direct bit to Carry Move direct bit to Carry Move Carry to direct bit Jump if Carry is set Jump if Carry is not set Jump if direct bit is set Jump if direct bit is not set Jump if direct bit is set and clear bit 1 2 1 2 1 2 2 2 2 2 2 2 2 2 3 3 3 1 2 1 2 1 2 2 2 2 2 2 2 2/3 2/3 3/4 3/4 3/4 Absolute subroutine call Long subroutine call Return from subroutine Return from interrupt Absolute jump Long jump Short jump (relative address) Jump indirect relative to DPTR Jump if A equals zero Jump if A does not equal zero Compare direct byte to A and jump if not equal Compare immediate to A and jump if not equal Compare immediate to Register and jump if not equal Compare immediate to indirect and jump if not equal Decrement Register and jump if not zero Decrement direct byte and jump if not zero No operation 2 3 1 1 2 3 2 1 2 2 3 3 3 3 4 5 5 3 4 3 3 2/3 2/3 4/5 3/4 3/4 3 4/5 2 3 1 2/3 3/4 1 Program Branching ACALL addr11 LCALL addr16 RET RETI AJMP addr11 LJMP addr16 SJMP rel JMP @A+DPTR JZ rel JNZ rel CJNE A, direct, rel CJNE A, #data, rel CJNE Rn, #data, rel CJNE @Ri, #data, rel DJNZ Rn, rel DJNZ direct, rel NOP Rev. 1.4 85 C8051F52x/F52xA/F53x/F53xA Notes on Registers, Operands and Addressing Modes: Rn - Register R0–R7 of the currently selected register bank. @Ri - Data RAM location addressed indirectly through R0 or R1. rel - 8-bit, signed (two’s complement) offset relative to the first byte of the following instruction. Used by SJMP and all conditional jumps. direct - 8-bit internal data location’s address. This could be a direct-access Data RAM location (0x00– 0x7F) or an SFR (0x80–0xFF). #data - 8-bit constant #data16 - 16-bit constant bit - Direct-accessed bit in Data RAM or SFR addr11 - 11-bit destination address used by ACALL and AJMP. The destination must be within the same 2 kB page of program memory as the first byte of the following instruction. addr16 - 16-bit destination address used by LCALL and LJMP. The destination may be anywhere within the 7680 bytes of program memory space. There is one unused opcode (0xA5) that performs the same function as NOP. All mnemonics copyrighted © Intel Corporation 1980. 8.2. Register Descriptions Following are descriptions of SFRs related to the operation of the CIP-51 System Controller. Reserved bits should not be set to logic 1. Future product versions may use these bits to implement new features in which case the reset value of the bit will be logic 0, selecting the feature's default state. Detailed descriptions of the remaining SFRs are included in the sections of the datasheet associated with their corresponding system function. 86 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 8.1. SP: Stack Pointer R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000111 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0x81 Bits7–0: SP: Stack Pointer. The Stack Pointer holds the location of the top of the stack. The stack pointer is incremented before every PUSH operation. The SP register defaults to 0x07 after reset. SFR Definition 8.2. DPL: Data Pointer Low Byte R/W R/W R/W R/W R/W R/W R/W R/W Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Reset Value 00000000 SFR Address: 0x82 Bits7–0: DPL: Data Pointer Low. The DPL register is the low byte of the 16-bit DPTR. DPTR is used to access indirectly addressed XRAM and Flash memory. SFR Definition 8.3. DPH: Data Pointer High Byte R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0x83 Bits7–0: DPH: Data Pointer High. The DPH register is the high byte of the 16-bit DPTR. DPTR is used to access indirectly addressed XRAM and Flash memory. Rev. 1.4 87 C8051F52x/F52xA/F53x/F53xA SFR Definition 8.4. PSW: Program Status Word R/W R/W R/W R/W R/W R/W R/W R Reset Value CY AC F0 RS1 RS0 OV F1 PARITY 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Bit Addressable SFR Address: 0xD0 Bit7: CY: Carry Flag. This bit is set when the last arithmetic operation resulted in a carry (addition) or a borrow (subtraction). It is cleared to 0 by all other arithmetic operations. Bit6: AC: Auxiliary Carry Flag This bit is set when the last arithmetic operation resulted in a carry into (addition) or a borrow from (subtraction) the high order nibble. It is cleared to 0 by all other arithmetic operations. Bit5: F0: User Flag 0. This is a bit-addressable, general purpose flag for use under software control. Bits4–3: RS1–RS0: Register Bank Select. These bits select which register bank is used during register accesses. RS1 0 0 1 1 Bit2: Bit1: Bit0: 88 RS0 0 1 0 1 Register Bank 0 1 2 3 Address 0x00–0x07 0x08–0x0F 0x10–0x17 0x18–0x1F OV: Overflow Flag. This bit is set to 1 under the following circumstances: • An ADD, ADDC, or SUBB instruction causes a sign-change overflow. • A MUL instruction results in an overflow (result is greater than 255). • A DIV instruction causes a divide-by-zero condition. The OV bit is cleared to 0 by the ADD, ADDC, SUBB, MUL, and DIV instructions in all other cases. F1: User Flag 1. This is a bit-addressable, general purpose flag for use under software control. PARITY: Parity Flag. This bit is set to 1 if the sum of the eight bits in the accumulator is odd and cleared if the sum is even. Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 8.5. ACC: Accumulator R/W R/W R/W R/W R/W R/W R/W R/W Reset Value ACC.7 ACC.6 ACC.5 ACC.4 ACC.3 ACC.2 ACC.1 ACC.0 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Bit Addressable SFR Address: 0xE0 Bits7–0: ACC: Accumulator. This register is the accumulator for arithmetic operations. SFR Definition 8.6. B: B Register R/W R/W R/W R/W R/W R/W R/W R/W Reset Value B.7 B.6 B.5 B.4 B.3 B.2 B.1 B.0 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Bit Addressable SFR Address: 0xF0 Bits7–0: B: B Register. This register serves as a second accumulator for certain arithmetic operations. 8.3. Power Management Modes The CIP-51 core has two software programmable power management modes: Idle and Stop. Idle mode halts the CPU while leaving the peripherals and internal clocks active. In Stop mode, the CPU is halted, all interrupts and timers (except the Missing Clock Detector) are inactive, and the internal oscillator is stopped (analog peripherals remain in their selected states; the external oscillator is not affected). Since clocks are running in Idle mode, power consumption is dependent upon the system clock frequency and the number of peripherals left in active mode before entering Idle. Stop mode consumes the least power. SFR Definition 8.7 describes the Power Control Register (PCON) used to control the CIP-51's power management modes. Although the CIP-51 has Idle and Stop modes built in (as with any standard 8051 architecture), power management of the entire MCU is better accomplished by enabling/disabling individual peripherals as needed. Each analog peripheral can be disabled when not in use and placed in low power mode. Digital peripherals, such as timers or serial buses, draw little power when they are not in use. Turning off the oscillators lowers power consumption considerably; however a reset is required to restart the MCU. The C8051F52x/F52xA/F53x/F53xA devices feature a low-power SUSPEND mode, which stops the internal oscillator until a wakening event occurs. See Section “14.1.1. Internal Oscillator Suspend Mode” on page 136 for more information. Rev. 1.4 89 C8051F52x/F52xA/F53x/F53xA 8.3.1. Idle Mode Setting the Idle Mode Select bit (PCON.0) causes the CIP-51 to halt the CPU and enter Idle mode as soon as the instruction that sets the bit completes execution. All internal registers and memory maintain their original data. All analog and digital peripherals can remain active during Idle mode. Idle mode is terminated when an enabled interrupt is asserted or a reset occurs. The assertion of an enabled interrupt will cause the Idle Mode Selection bit (PCON.0) to be cleared and the CPU to resume operation. The pending interrupt will be serviced and the next instruction to be executed after the return from interrupt (RETI) will be the instruction immediately following the one that set the Idle Mode Select bit. If Idle mode is terminated by an internal or external reset, the CIP-51 performs a normal reset sequence and begins program execution at address 0x0000. If enabled, the Watchdog Timer (WDT) will eventually cause an internal watchdog reset and thereby terminate the Idle mode. This feature protects the system from an unintended permanent shutdown in the event of an inadvertent write to the PCON register. If this behavior is not desired, the WDT may be disabled by software prior to entering the Idle mode if the WDT was initially configured to allow this operation. This provides the opportunity for additional power savings, allowing the system to remain in the Idle mode indefinitely, waiting for an external stimulus to wake up the system. 8.3.2. Stop Mode Setting the Stop Mode Select bit (PCON.1) causes the CIP-51 to enter Stop mode as soon as the instruction that sets the bit completes execution. In Stop mode the internal oscillator, CPU, and all digital peripherals are stopped; the state of the external oscillator circuit is not affected. Each analog peripheral (including the external oscillator circuit) may be shut down individually prior to entering Stop Mode. Stop mode can only be terminated by an internal or external reset. On reset, the CIP-51 performs the normal reset sequence and begins program execution at address 0x0000. If enabled, the Missing Clock Detector will cause an internal reset and thereby terminate the Stop mode. The Missing Clock Detector should be disabled if the CPU is to be put to in STOP mode for longer than the MCD timeout period of 100 μs. 8.3.3. Suspend Mode The C8051F52x/F52xA/F53x/F53xA devices feature a low-power Suspend mode, which stops the internal oscillator until a wakening event occurs. See Section Section “14.1.1. Internal Oscillator Suspend Mode” on page 136 for more information. Note: When entering Suspend mode, firmware must set the ZTCEN bit in REF0CN (SFR Definition 5.1). 90 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 8.7. PCON: Power Control R/W R/W R/W R/W R/W R/W Reserved Reserved Reserved Reserved Reserved Reserved Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 R/W R/W Reset Value STOP IDLE 00000000 Bit1 Bit0 SFR Address: 0x87 Bits7–2: RESERVED. Bit1: STOP: STOP Mode Select. Writing a 1 to this bit will place the CIP-51 into STOP mode. This bit will always read 0. 1: CIP-51 forced into power-down mode. (Turns off internal oscillator). Bit0: IDLE: IDLE Mode Select. Writing a 1 to this bit will place the CIP-51 into IDLE mode. This bit will always read 0. 1: CIP-51 forced into IDLE mode. (Shuts off clock to CPU, but clock to Timers, Interrupts, and all peripherals remain active.) Rev. 1.4 91 C8051F52x/F52xA/F53x/F53xA 9. Memory Organization and SFRs The memory organization of the C8051F52x/F52xA/F53x/F53xA is similar to that of a standard 8051. There are two separate memory spaces: program memory and data memory. Program and data memory share the same address space but are accessed via different instruction types. The memory map is shown in Figure 9.1. PROGRAM/DATA MEMORY (Flash) 'F520/0A/1/1A and 'F530/0A/1/1A 0x1E00 0x1DFF 0xFF RESERVED 8 kB Flash (In-System Programmable in 512 Byte Sectors) 0x0000 'F523/3A/4/4A and 'F533/3A/4/4A 0x1000 0x0FFF DATA MEMORY (RAM) INTERNAL DATA ADDRESS SPACE 0x80 0x7F Upper 128 RAM (Indirect Addressing Only) (Direct and Indirect Addressing) 0x30 0x2F 0x20 0x1F 0x00 Bit Addressable Special Function Register's (Direct Addressing Only) Lower 128 RAM (Direct and Indirect Addressing) General Purpose Registers RESERVED 4 kB Flash 0x0000 (In-System Programmable in 512 Byte Sectors) 'F526/6A/7/7A and 'F536/6A/7/7A 0x0800 0x07FF RESERVED 2 kB Flash (In-System Programmable in 512 Byte Sectors) 0x0000 Figure 9.1. Memory Map 9.1. Program Memory The CIP-51 core has a 64 kB program memory space. The C8051F520/0A/1/1A and C8051F530/0A/1/1A implement 8 kB of this program memory space as in-system, re-programmable Flash memory, organized in a contiguous block from addresses 0x0000 to 0x1FFF. Addresses above 0x1DFF are reserved on the 8 kB devices. The C8051F523/3A/4/4A and C8051F533/3A/4/4A implement 4 kB of Flash from addresses 0x0000 to 0x0FFF. The C8051F526/6A/7/7A and C8051F536/6A/7/7A implement 2 kB of Flash from addresses 0x0000 to 0x07FF. Program memory is normally assumed to be read-only. However, the C8051F52x/F52xA/F53x/F53xA can write to program memory by setting the Program Store Write Enable bit (PSCTL.0) and using the MOVX write instruction. This feature provides a mechanism for updates to program code and use of the program memory space for non-volatile data storage. Refer to Section “12. Flash Memory” on page 113 for further details. Rev. 1.4 92 C8051F52x/F52xA/F53x/F53xA 9.2. Data Memory The C8051F52x/F52xA/F53x/F53xAincludes 256 bytes of internal RAM mapped into the data memory space from 0x00 through 0xFF. The lower 128 bytes of data memory are used for general purpose registers and scratch pad memory. Either direct or indirect addressing may be used to access the lower 128 bytes of data memory. Locations 0x00 through 0x1F are addressable as four banks of general purpose registers, each bank consisting of eight byte-wide registers. The next 16 bytes, locations 0x20 through 0x2F, may either be addressed as bytes or as 128 bit locations accessible with the direct addressing mode. The upper 128 bytes of data memory are accessible only by indirect addressing. This region occupies the same address space as the Special Function Registers (SFRs) but is physically separate from the SFR space. The addressing mode used by an instruction when accessing locations above 0x7F determines whether the CPU accesses the upper 128 bytes of data memory space or the SFRs. Instructions that use direct addressing will access the SFR space. Instructions using indirect addressing above 0x7F access the upper 128 bytes of data memory. Figure 9.1 illustrates the data memory organization of the C8051F52x/ F52xA/F53x/F53xA. 9.3. General Purpose Registers The lower 32 bytes of data memory (locations 0x00 through 0x1F) may be addressed as four banks of general-purpose registers. Each bank consists of eight byte-wide registers designated R0 through R7. Only one of these banks may be enabled at a time. Two bits in the program status word, RS0 (PSW.3) and RS1 (PSW.4), select the active register bank (see description of the PSW in SFR Definition 8.4. PSW: Program Status Word). This allows fast context switching when entering subroutines and interrupt service routines. Indirect addressing modes use registers R0 and R1 as index registers. 9.4. Bit Addressable Locations In addition to direct access to data memory organized as bytes, the sixteen data memory locations at 0x20 through 0x2F are also accessible as 128 individually addressable bits. Each bit has a bit address from 0x00 to 0x7F. Bit 0 of the byte at 0x20 has bit address 0x00 while bit 7 of the byte at 0x20 has bit address 0x07. Bit 7 of the byte at 0x2F has bit address 0x7F. A bit access is distinguished from a full byte access by the type of instruction used (bit source or destination operands as opposed to a byte source or destination). The MCS-51™ assembly language allows an alternate notation for bit addressing of the form XX.B where XX is the byte address and B is the bit position within the byte. For example, the instruction: MOV C, 22.3h moves the Boolean value at 0x13 (bit 3 of the byte at location 0x22) into the Carry flag. 9.5. Stack A programmer's stack can be located anywhere in the 256-byte data memory. The stack area is designated using the Stack Pointer (SP, 0x81) SFR. The SP will point to the last location used. The next value pushed on the stack is placed at SP+1 and then SP is incremented. A reset initializes the stack pointer to location 0x07. Therefore, the first value pushed on the stack is placed at location 0x08, which is also the first register (R0) of register bank 1. Thus, if more than one register bank is to be used, the SP should be initialized to a location in the data memory not being used for data storage. The stack depth can extend up to 256 bytes. 9.6. Special Function Registers The direct-access data memory locations from 0x80 to 0xFF constitute the special function registers (SFRs). The SFRs provide control and data exchange with the CIP-51's resources and peripherals. The CIP-51 duplicates the SFRs found in a typical 8051 implementation as well as implementing additional 93 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFRs used to configure and access the sub-systems unique to the MCU. This allows the addition of new functionality while retaining compatibility with the MCS-51™ instruction set. Table 9.1 lists the SFRs implemented in the CIP-51 System Controller. The SFR registers are accessed anytime the direct addressing mode is used to access memory locations from 0x80 to 0xFF. SFRs with addresses ending in 0x0 or 0x8 (e.g. P0, TCON, IE, etc.) are bit-addressable as well as byte-addressable. All other SFRs are byte-addressable only. Unoccupied addresses in the SFR space are reserved for future use. Accessing these areas will have an indeterminate effect and should be avoided. Refer to the corresponding pages of the data sheet, as indicated in Table 9.2, for a detailed description of each register. Table 9.1. Special Function Register (SFR) Memory Map F8 F0 E8 E0 D8 D0 C8 C0 B8 B0 A8 A0 98 90 88 80 SPI0CN B ADC0CN ACC PCA0CN PSW TMR2CN IP OSCIFIN IE SCON0 P1 TCON P0 0(8) (bit addressable) PCA0L PCA0H PCA0CPL0 PCA0CPH0 VDDMON P0MDIN P1MDIN EIP1 PCA0CPL1 PCA0CPH1 PCA0CPL2 PCA0CPH2 RSTSRC XBR0 XBR1 IT01CF EIE1 PCA0MD PCA0CPM0 PCA0CPM1 PCA0CPM2 REF0CN P0SKIP P1SKIP P0MAT REG0CN TMR2RLL TMR2RLH TMR2L TMR2H P1MAT ADC0GTL ADC0GTH ADC0LTL ADC0LTH P0MASK ADC0TK ADC0MX ADC0CF ADC0L ADC0 P1MASK OSCXCN OSCICN OSCICL FLKEY CLKSEL SPI0CFG SPI0CKR SPI0DAT P0MDOUT P1MDOUT SBUF0 CPT0CN CPT0MD CPT0MX LINADDR LINDATA LINCF TMOD TL0 TL1 TH0 TH1 CKCON PSCTL SP DPL DPH PCON 1(9) 2(A) 3(B) 4(C) 5(D) 6(E) 7(F) Rev. 1.4 94 C8051F52x/F52xA/F53x/F53xA Table 9.2. Special Function Registers SFRs are listed in alphabetical order. All undefined SFR locations are reserved Register Address Description Page ACC 0xE0 Accumulator 89 ADC0CF 0xBC ADC0 Configuration 65 ADC0CN 0xE8 ADC0 Control 67 ADC0H 0xBE ADC0 66 ADC0L 0xBD ADC0 66 ADC0GTH 0xC4 ADC0 Greater-Than Data High Byte 69 ADC0GTL 0xC3 ADC0 Greater-Than Data Low Byte 69 ADC0LTH 0xC6 ADC0 Less-Than Data High Byte 70 ADC0LTL 0xC5 ADC0 Less-Than Data Low Byte 70 ADC0MX 0xBB ADC0 Channel Select 64 ADC0TK 0xBA ADC0 Tracking Mode Select 68 B 0xF0 B Register 89 CKCON 0x8E Clock Control 188 CLKSEL 0xA9 Clock Select 143 CPT0CN 0x9B Comparator0 Control 78 CPT0MD 0x9D Comparator0 Mode Selection 80 CPT0MX 0x9F Comparator0 MUX Selection 79 DPH 0x83 Data Pointer High 87 DPL 0x82 Data Pointer Low 87 EIE1 0xE6 Extended Interrupt Enable 1 102 EIP1 0xF6 Extended Interrupt Priority 1 103 FLKEY 0xB7 Flash Lock and Key 119 IE 0xA8 Interrupt Enable 100 IP 0xB8 Interrupt Priority 101 IT01CF 0xE4 INT0/INT1 Configuration 105 LINADDR 0x92 LIN indirect address pointer 172 LINCF 0x95 LIN master-slave and automatic baud rate selection 173 LINDATA 0x93 LIN indirect data buffer 172 OSCICL 0xB3 Internal Oscillator Calibration 138 95 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Table 9.2. Special Function Registers (Continued) SFRs are listed in alphabetical order. All undefined SFR locations are reserved Register Address Description Page OSCICN 0xB2 Internal Oscillator Control 137 OSCXCN 0xB1 External Oscillator Control 142 P0 0x80 Port 0 Latch 129 P0MASK 0xC7 Port 0 Mask 131 P0MAT 0xD7 Port 0 Match 131 P0MDIN 0xF1 Port 0 Input Mode Configuration 129 P0MDOUT 0xA4 Port 0 Output Mode Configuration 130 P0SKIP 0xD4 Port 0 Skip 130 P1 0x90 Port 1 Latch 132 P1MASK 0xBF Port 1 Mask 134 P1MAT 0xCF Port 1 Match 134 P1MDIN 0xF2 Port 1 Input Mode Configuration 132 P1MDOUT 0xA5 Port 1 Output Mode Configuration 133 P1SKIP 0xD5 Port 1 Skip 133 PCA0CN 0xD8 PCA Control 206 PCA0CPH0 0xFC PCA Capture 0 High 209 PCA0CPH1 0xEA PCA Capture 1 High 209 PCA0CPH2 0xEC PCA Capture 2 High 209 PCA0CPL0 0xFB PCA Capture 0 Low 209 PCA0CPL1 0xE9 PCA Capture 1 Low 209 PCA0CPL2 0xEB PCA Capture 2 Low 209 PCA0CPM0 0xDA PCA Module 0 Mode 208 PCA0CPM1 0xDB PCA Module 1 Mode 208 PCA0CPM2 0xDC PCA Module 2 Mode 208 PCA0H 0xFA PCA Counter High 209 PCA0L 0xF9 PCA Counter Low 209 PCA0MD 0xD9 PCA Mode 207 PCON 0x87 Power Control 91 PSCTL 0x8F Program Store R/W Control 119 PSW 0xD0 Program Status Word 88 Rev. 1.4 96 C8051F52x/F52xA/F53x/F53xA Table 9.2. Special Function Registers (Continued) SFRs are listed in alphabetical order. All undefined SFR locations are reserved Register Address Description Page REF0CN 0xD1 Voltage Reference Control 73 REG0CN 0xC9 Voltage Regulator Control 75 RSTSRC 0xEF Reset Source Configuration/Status 112 SBUF0 0x99 UART0 Data Buffer 150 SCON0 0x98 UART0 Control 149 SP 0x81 Stack Pointer 87 SPI0CFG 0xA1 SPI Configuration 157 SPI0CKR 0xA2 SPI Clock Rate Control 159 SPI0CN 0xF8 SPI Control 158 SPI0DAT 0xA3 SPI Data 160 TCON 0x88 Timer/Counter Control 186 TH0 0x8C Timer/Counter 0 High 189 TH1 0x8D Timer/Counter 1 High 189 TL0 0x8A Timer/Counter 0 Low 189 TL1 0x8B Timer/Counter 1 Low 189 TMOD 0x89 Timer/Counter Mode 187 TMR2CN 0xC8 Timer/Counter 2 Control 193 TMR2H 0xCD Timer/Counter 2 High 194 TMR2L 0xCC Timer/Counter 2 Low 194 TMR2RLH 0xCB Timer/Counter 2 Reload High 194 TMR2RLL 0xCA Timer/Counter 2 Reload Low 194 VDDMON 0xFF VDD Monitor Control 109 XBR0 0xE1 Port I/O Crossbar Control 0 127 XBR1 0xE2 Port I/O Crossbar Control 1 128 97 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 10. Interrupt Handler The C8051F52x/F52xA/F53x/F53xA family includes an extended interrupt system with two selectable priority levels. The allocation of interrupt sources between on-chip peripherals and external input pins varies according to the specific version of the device. Each interrupt source has one or more associated interruptpending flag(s) located in an SFR. When a peripheral or external source meets a valid interrupt condition, the associated interrupt-pending flag is set to logic 1. If interrupts are enabled for the source, an interrupt request is generated when the interrupt-pending flag is set. As soon as execution of the current instruction is complete, the CPU generates an LCALL to a predetermined address to begin execution of an interrupt service routine (ISR). Each ISR must end with an RETI instruction, which returns program execution to the next instruction that would have been executed if the interrupt request had not occurred. If interrupts are not enabled, the interrupt-pending flag is ignored by the hardware and program execution continues as normal. (The interrupt-pending flag is set to logic 1 regardless of the interrupt's enable/disable state.) Each interrupt source can be individually enabled or disabled through the use of an associated interrupt enable bit in the Interrupt Enable and Extended Interrupt Enable SFRs. However, interrupts must first be globally enabled by setting the EA bit (IE.7) to logic 1 before the individual interrupt enables are recognized. Setting the EA bit to logic 0 disables all interrupt sources regardless of the individual interruptenable settings. Note that interrupts which occur when the EA bit is set to logic 0 will be held in a pending state, and will not be serviced until the EA bit is set back to logic 1. Some interrupt-pending flags are automatically cleared by the hardware when the CPU vectors to the ISR. However, most are not cleared by the hardware and must be cleared by software before returning from the ISR. If an interrupt-pending flag remains set after the CPU completes the return-from-interrupt (RETI) instruction, a new interrupt request will be generated immediately and the CPU will re-enter the ISR after the completion of the next instruction. 10.1. MCU Interrupt Sources and Vectors The C8051F52x/F52xA/F53x/F53xA MCUs support 15 interrupt sources. Software can simulate an interrupt by setting any interrupt-pending flag to logic 1. If interrupts are enabled for the flag, an interrupt request will be generated and the CPU will vector to the ISR address associated with the interrupt-pending flag. MCU interrupt sources, associated vector addresses, priority order, and control bits are summarized in Table 10.1 on page 99. Refer to the data sheet section associated with a particular on-chip peripheral for information regarding valid interrupt conditions for the peripheral and the behavior of its interrupt-pending flag(s). 10.2. Interrupt Priorities Each interrupt source can be individually programmed to one of two priority levels: low or high. A low priority interrupt service routine can be preempted by a high priority interrupt. A high priority interrupt cannot be preempted. Each interrupt has an associated interrupt priority bit in an SFR (IP or EIP1) used to configure its priority level. Low priority is the default. If two interrupts are recognized simultaneously, the interrupt with the higher priority is serviced first. If both interrupts have the same priority level, a fixed priority order is used to arbitrate, given in Table 10.1. 10.3. Interrupt Latency Interrupt response time depends on the state of the CPU when the interrupt occurs. Pending interrupts are sampled and priority decoded each system clock cycle. Therefore, the fastest possible response time is 5 system clock cycles: 1 clock cycle to detect the interrupt and 4 clock cycles to complete the LCALL to the ISR. If an interrupt is pending when a RETI is executed, a single instruction is executed before an LCALL is made to service the pending interrupt. Therefore, the maximum response time for an interrupt (when no other interrupt is currently being serviced or the new interrupt is of greater priority) occurs when the CPU is performing an RETI instruction followed by a DIV as the next instruction. In this case, the response time is Rev. 1.4 98 C8051F52x/F52xA/F53x/F53xA 18 system clock cycles: 1 clock cycle to detect the interrupt, 5 clock cycles to execute the RETI, 8 clock cycles to complete the DIV instruction, and 4 clock cycles to execute the LCALL to the ISR. If the CPU is executing an ISR for an interrupt with equal or higher priority, the new interrupt will not be serviced until the current ISR completes, including the RETI and following instruction. Interrupt Priority Vector Order Pending Flag Cleared by HW? Interrupt Source Bit addressable? Table 10.1. Interrupt Summary Priority Control Always Enabled Always Highest Reset 0x0000 Top None External Interrupt 0(INT0) 0x0003 0 IE0 (TCON.1) Y Y EX0 (IE.0) PX0 (IP.0) Timer 0 Overflow 0x000B 1 TF0 (TCON.5) Y Y ET0 (IE.1) PT0 (IP.1) External Interrupt 1(INT0) 0x0013 2 IE1 (TCON.3) Y Y EX1 (IE.2) PX1 (IP.2) Timer 1 Overflow 0x001B 3 TF1 (TCON.7) Y Y ET1 (IE.3) PT1 (IP.3) UART 0x0023 4 RI0 (SCON0.0) TI0 (SCON0.1) Y N ES0 (IE.4) PS0 (IP.4) Timer 2 Overflow 0x002B 5 TF2H (TMR2CN.7) TF2L (TMR2CN.6) Y N ET2 (IE.5) PT2 (IP.5) SPI0 0x0033 6 SPIF (SPI0CN.7) WCOL (SPI0CN.6) MODF (SPI0CN.5) RXOVRN (SPI0CN.4) Y N ESPI0 (IE.6) PSPI0 (IP.6) ADC0 Window Comparator 0x003B 7 AD0WINT (ADC0CN.3) Y N EWADC0 (EIE1.0) PWADC0 (EIP1.0) ADC0 End of Conversion 0x0043 8 AD0INT (ADC0CN.5) Y N EADC0 (EIE1.1) PADC0 (EIP1.1) Programmable Counter Array 0x004B 9 CF (PCA0CN.7) CCFn (PCA0CN.n) Y N EPCA0 (EIE1.2) PPCA0 (EIP1.2) Comparator Falling Edge 0x0053 10 CP0FIF (CPT0CN.4) N N ECPF (EIE1.3) PCPF (EIP1.3) Comparator Rising Edge 0x005B 11 CP0RIF (CPT0CN.5) N N ECPR (EIE1.4) PCPR (EIP1.4) LIN Interrupt 0x0063 12 LININT (LINST.3) N N* ELIN (EIE1.5) PLIN (EIP1.5) Voltage Regulator Dropout 0x006B 13 N/A N/A N/A EREG0 (EIE1.6) PREG0 (EIP1.6) Port Match 14 N/A N/A N/A EMAT (EIE1.7) PMAT (EIP1.7) 0x0073 Note: Software must set the RSTINT bit (LINCTRL.3) to clear the LININT flag. 99 Rev. 1.4 N/A N/A Enable Flag C8051F52x/F52xA/F53x/F53xA 10.4. Interrupt Register Descriptions The SFRs used to enable the interrupt sources and set their priority level are described below. Refer to the data sheet section associated with a particular on-chip peripheral for information regarding valid interrupt conditions for the peripheral and the behavior of its interrupt-pending flag(s). SFR Definition 10.1. IE: Interrupt Enable R/W R/W R/W R/W R/W R/W R/W R/W Reset Value EA ESPI0 ET2 ES0 ET1 EX1 ET0 EX0 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Bit Addressable SFR Address: 0xA8 Bit7: Bit6: Bit5: Bit4: Bit3: Bit2: Bit1: Bit0: EA: Global Interrupt Enable. This bit globally enables/disables all interrupts. It overrides the individual interrupt mask settings. 0: Disable all interrupt sources. 1: Enable each interrupt according to its individual mask setting. ESPI0: Enable Serial Peripheral Interface (SPI0) Interrupt. This bit sets the masking of the SPI0 interrupts. 0: Disable all SPI0 interrupts. 1: Enable interrupt requests generated by SPI0. ET2: Enable Timer 2 Interrupt. This bit sets the masking of the Timer 2 interrupt. 0: Disable Timer 2 interrupt. 1: Enable interrupt requests generated by the TF2L or TF2H flags. ES0: Enable UART0 Interrupt. This bit sets the masking of the UART0 interrupt. 0: Disable UART0 interrupt. 1: Enable UART0 interrupt. ET1: Enable Timer 1 Interrupt. This bit sets the masking of the Timer 1 interrupt. 0: Disable all Timer 1 interrupt. 1: Enable interrupt requests generated by the TF1 flag. EX1: Enable External Interrupt 1. This bit sets the masking of the external interrupt 1. 0: Disable external interrupt 1. 1: Enable extern interrupt 1 requests. ET0: Enable Timer 0 Interrupt. This bit sets the masking of the Timer 0 interrupt. 0: Disable all Timer 0 interrupt. 1: Enable interrupt requests generated by the TF0 flag. EX0: Enable External Interrupt 0. This bit sets the masking of the external interrupt 0. 0: Disable external interrupt 0. 1: Enable extern interrupt 0 requests. Rev. 1.4 100 C8051F52x/F52xA/F53x/F53xA SFR Definition 10.2. IP: Interrupt Priority R R/W R/W R/W R/W R/W R/W R/W Reset Value - PSPI0 PT2 PS0 PT1 PX1 PT0 PX0 10000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Bit Addressable SFR Address: 0xB8 Bit7: Bit6: Bit5: Bit4: Bit3: Bit2: Bit1: Bit0: 101 UNUSED. Read = 1b; Write = don't care. PSPI0: Serial Peripheral Interface (SPI0) Interrupt Priority Control. This bit sets the priority of the SPI0 interrupt. 0: SPI0 interrupt set to low priority level. 1: SPI0 interrupt set to high priority level. PT2: Timer 2 Interrupt Priority Control. This bit sets the priority of the Timer 2 interrupt. 0: Timer 2 interrupt set to low priority level. 1: Timer 2 interrupt set to high priority level. PS0: UART0 Interrupt Priority Control. This bit sets the priority of the UART0 interrupt. 0: UART0 interrupt set to low priority level. 1: UART0 interrupt set to high priority level. PT1: Timer 1 Interrupt Priority Control. This bit sets the priority of the Timer 1 interrupt. 0: Timer 1 interrupt set to low priority level. 1: Timer 1 interrupt set to high priority level. PX1: External Interrupt 0 Priority Control. This bit sets the priority of the external interrupt 1. 0: INT1 interrupt set to low priority level. 1: INT1 interrupt set to high priority level. PT0: Timer 0 Interrupt Priority Control. This bit sets the priority of the Timer 0 interrupt. 0: Timer 0 interrupt set to low priority level. 1: Timer 0 interrupt set to high priority level. PX0: External Interrupt 0 Priority Control. This bit sets the priority of the external interrupt 0. 0: INT0 interrupt set to low priority level. 1: INT0 interrupt set to high priority level. Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 10.3. EIE1: Extended Interrupt Enable 1 R/W R/W R/W R/W R/W R/W R/W EMAT EREG0 ELIN ECPR ECPF EPCA0 EADC0 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 R/W Bit0 SFR Address: Bit7: Bit6: Bit5: Bit4: Bit3: Bit2: Bit1: Bit0: Reset Value EWADC0 00000000 0xE6 EMAT: Enable Port Match Interrupt. This bit sets the masking of the Port Match interrupt. 0: Disable the Port Match interrupt. 1: Enable the Port Match interrupt. EREG0: Enable Voltage Regulator Interrupt. This bit sets the masking of the Voltage Regulator Dropout interrupt. 0: Disable the Voltage Regulator Dropout interrupt. 1: Enable the Voltage Regulator Dropout interrupt. ELIN: Enable LIN Interrupt. This bit sets the masking of the LIN interrupt. 0: Disable LIN interrupts. 1: Enable LIN interrupt requests. ECPR: Enable Comparator 0 Rising Edge Interrupt This bit sets the masking of the CP0 Rising Edge interrupt. 0: Disable CP0 Rising Edge Interrupt. 1: Enable CP0 Rising Edge Interrupt. ECPF: Enable Comparator 0 Falling Edge Interrupt This bit sets the masking of the CP0 Falling Edge interrupt. 0: Disable CP0 Falling Edge Interrupt. 1: Enable CP0 Falling Edge Interrupt. EPCA0: Enable Programmable Counter Array (PCA0) Interrupt. This bit sets the masking of the PCA0 interrupts. 0: Disable all PCA0 interrupts. 1: Enable interrupt requests generated by PCA0. EADC0: Enable ADC0 Conversion Complete Interrupt. This bit sets the masking of the ADC0 Conversion Complete interrupt. 0: Disable ADC0 Conversion Complete interrupt. 1: Enable interrupt requests generated by the AD0INT flag. EWADC0: Enable ADC0 Window Comparison Interrupt. This bit sets the masking of the ADC0 Window Comparison interrupt. 0: Disable ADC0 Window Comparison interrupt. 1: Enable interrupt requests generated by the AD0WINT flag. Rev. 1.4 102 C8051F52x/F52xA/F53x/F53xA SFR Definition 10.4. EIP1: Extended Interrupt Priority 1 R/W R/W R/W R/W R/W R/W R/W PMAT PREG0 PLIN PCPR PCPF PPAC0 PREG0 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 R/W Bit0 SFR Address: Bit7: Bit6: Bit5: Bit4: Bit3: Bit2: Bit1: Bit0: 103 PMAT. Port Match Interrupt Priority Control. This bit sets the priority of the Port Match interrupt. 0: Port Match interrupt set to low priority level. 1: Port Match interrupt set to high priority level. PREG0: Voltage Regulator Interrupt Priority Control. This bit sets the priority of the Voltage Regulator interrupt. 0: Voltage Regulator interrupt set to low priority level. 1: Voltage Regulator interrupt set to high priority level. PLIN: LIN Interrupt Priority Control. This bit sets the priority of the CP0 interrupt. 0: LIN interrupt set to low priority level. 1: LIN interrupt set to high priority level. PCPR: Comparator Rising Edge Interrupt Priority Control. This bit sets the priority of the Rising Edge Comparator interrupt. 0: Comparator interrupt set to low priority level. 1: Comparator interrupt set to high priority level. PCPF: Comparator falling Edge Interrupt Priority Control. This bit sets the priority of the Falling Edge Comparator interrupt. 0: Comparator interrupt set to low priority level. 1: Comparator interrupt set to high priority level. PPAC0: Programmable Counter Array (PCA0) Interrupt Priority Control. This bit sets the priority of the PCA0 interrupt. 0: PCA0 interrupt set to low priority level. 1: PCA0 interrupt set to high priority level. PREG0: ADC0 Conversion Complete Interrupt Priority Control. This bit sets the priority of the ADC0 Conversion Complete interrupt. 0: ADC0 Conversion Complete interrupt set to low priority level. 1: ADC0 Conversion Complete interrupt set to high priority level. PWADC0: ADC0 Window Comparison Interrupt Priority Control. This bit sets the priority of the ADC0 Window Comparison interrupt. 0: ADC0 Window Comparison interrupt set to low priority level. 1: ADC0 Window Comparison interrupt set to high priority level. Rev. 1.4 Reset Value PWADC0 00000000 0xF6 C8051F52x/F52xA/F53x/F53xA 10.5. External Interrupts The INT0 and INT0 external interrupt sources are configurable as active high or low, edge or level sensitive. The IN0PL (INT0 Polarity) and IN1PL (INT0 Polarity) bits in the IT01CF register select active high or active low; the IT0 and IT1 bits in TCON (Section “18.1. Timer 0 and Timer 1” on page 182) select level or edge sensitive. The table below lists the possible configurations. IT0 IN0PL INT0 Interrupt IT1 IN1PL INT1 Interrupt 1 0 Active low, edge sensitive 1 0 Active low, edge sensitive 1 1 Active high, edge sensitive 1 1 Active high, edge sensitive 0 0 Active low, level sensitive 0 0 Active low, level sensitive 0 1 Active high, level sensitive 0 1 Active high, level sensitive INT0 and INT0 are assigned to Port pins as defined in the IT01CF register (see SFR Definition 10.5). Note that INT0 and INT0 Port pin assignments are independent of any Crossbar assignments. INT0 and INT0 will monitor their assigned Port pins without disturbing the peripheral that was assigned the Port pin via the Crossbar. To assign a Port pin only to INT0 and/or INT0, configure the Crossbar to skip the selected pin(s). This is accomplished by setting the associated bit in register XBR0 (see Section “13.1. Priority Crossbar Decoder” on page 122 for complete details on configuring the Crossbar). In the typical configuration, the external interrupt pins should be skipped in the crossbar and configured as open-drain with the pin latch set to 1. See Section “13. Port Input/Output” on page 120 for more information. IE0 (TCON.1) and IE1 (TCON.3) serve as the interrupt-pending flags for the INT0 and INT0 external interrupts, respectively. If an INT0 or INT0 external interrupt is configured as edge-sensitive, the corresponding interrupt-pending flag is automatically cleared by the hardware when the CPU vectors to the ISR. When configured as level sensitive, the interrupt-pending flag remains logic 1 while the input is active as defined by the corresponding polarity bit (IN0PL or IN1PL); the flag remains logic 0 while the input is inactive. The external interrupt source must hold the input active until the interrupt request is recognized. It must then deactivate the interrupt request before execution of the ISR completes or another interrupt request will be generated. Rev. 1.4 104 C8051F52x/F52xA/F53x/F53xA SFR Definition 10.5. IT01CF: INT0/INT1 Configuration R/W R/W R/W R/W R/W R/W R/W R/W Reset Value IN1PL IN1SL2 IN1SL1 IN1SL0 IN0PL IN0SL2 IN0SL1 IN0SL0 00000001 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xE4 Note: Refer to SFR Definition 18.1. “TCON: Timer Control” on page 186 for INT0/1 edge- or level-sensitive interrupt selection. Bit 7: IN1PL: INT0 Polarity 0: INT0 input is active low. 1: INT0 input is active high. Bits 6–4: IN1SL2–0: INT0 Port Pin Selection Bits These bits select which Port pin is assigned to INT0. Note that this pin assignment is independent of the Crossbar; INT0 will monitor the assigned Port pin without disturbing the peripheral that has been assigned the Port pin via the Crossbar. The Crossbar will not assign the Port pin to a peripheral if it is configured to skip the selected pin (accomplished by setting to 1 the corresponding bit in register P0SKIP). IN1SL2-0 INT1 Port Pin 000 P0.0 001 P0.1 010 P0.2 011 P0.3 100 P0.4 101 P0.5 110 P0.6* 111 P0.7* Note: Available in the C80151F53x/C8051F53xA parts. IN0PL: INT0 Polarity 0: INT0 interrupt is active low. 1: INT0 interrupt is active high. Bits 2–0: INT0SL2–0: INT0 Port Pin Selection Bits These bits select which Port pin is assigned to INT0. Note that this pin assignment is independent of the Crossbar. INT0 will monitor the assigned Port pin without disturbing the peripheral that has been assigned the Port pin via the Crossbar. The Crossbar will not assign the Port pin to a peripheral if it is configured to skip the selected pin (accomplished by setting to 1 the corresponding bit in register P0SKIP). Bit 3: IN0SL2-0 INT0 Port Pin 000 P0.0 001 P0.1 010 P0.2 011 P0.3 100 P0.4 101 P0.5 110 P0.6* 111 P0.7* Note: Available in the C80151F53x/C8051F53xA parts. 105 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 11. Reset Sources Reset circuitry allows the controller to be easily placed in a predefined default condition. On entry to this reset state, the following occur:  CIP-51 halts program execution  Special Function Registers (SFRs) are initialized to their defined reset values  External Port pins are forced to a known state  Interrupts and timers are disabled. All SFRs are reset to the predefined values noted in the SFR detailed descriptions. The contents of internal data memory are unaffected during a reset; any previously stored data is preserved. However, since the stack pointer SFR is reset, the stack is effectively lost, even though the data on the stack is not altered. The Port I/O latches are reset to 0xFF (all logic ones) in open-drain mode. Weak pullups are enabled during and after the reset. For VDD Monitor and power-on resets, the RST pin is driven low until the device exits the reset state. On exit from the reset state, the program counter (PC) is reset, and the system clock defaults to the internal oscillator. Refer to Section “14. Oscillators” on page 135 for information on selecting and configuring the system clock source. The Watchdog Timer is enabled with the system clock divided by 12 as its clock source (Section “19.3. Watchdog Timer Mode” on page 203 details the use of the Watchdog Timer). Program execution begins at location 0x0000. VDD Supply Monitor (VDDMON0) + - Supply Monitor (VDDMON1) C0RSEF + - Missing Clock Detector (oneshot) EN Enable (wired-OR) + - '0' (wired-OR) /RST Reset Funnel PCA WDT (Software Reset) SWRSF EN System Clock Illegal Flash Operation WDT Enable Px.x Comparator 0 MCD Enable Px.x Power On Reset Enable CIP-51 Microcontroller Core System Reset Extended Interrupt Handler Figure 11.1. Reset Sources Rev. 1.4 106 C8051F52x/F52xA/F53x/F53xA 11.1. Power-On Reset During power-up, the device is held in a reset state and the RST pin is driven low until VDD settles above VRST. VDD ramp time is defined as how fast VDD ramps from 0 V to VRST. An additional delay (TPORDelay) occurs before the device is released from reset. The VRST threshold and TPORDelay are specified in Table 2.8, “Reset Electrical Characteristics,” on page 32. Figure 11.2 plots the power-on and VDD monitor reset timing. Note: Please refer to Section “20.4. VDD Monitors and VDD Ramp Time” on page 211 for definition of VRST and VDD ramp time in older silicon revisions A and B. On exit from a power-on reset, the PORSF flag (RSTSRC.1) is set by hardware to logic 1. When PORSF is set, all of the other reset flags in the RSTSRC Register are indeterminate (PORSF is cleared by all other resets). Since all resets cause program execution to begin at the same location (0x0000), software can read the PORSF flag to determine if a power-up was the cause of reset. The contents of internal data memory should be assumed to be undefined after a power-on reset. Both the VDD monitors (VDDMON0 and VDDMON1) are enabled following a power-on reset. volts Note: Please refer to Section “11.2.1. VDD Monitor Thresholds and Minimum VDD” on page 108 for recommendations related to minimum VDD. VDD VD D V R ST 1.0 t Logic H IG H /RST T P O R D e lay Logic LO W VDD M onitor R eset P ow er-O n R eset Figure 11.2. Power-On and VDD Monitor Reset Timing 107 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 11.2. Power-Fail Reset / VDD Monitors (VDDMON0 and VDDMON1) C8051F52x-C/F53x-C devices include two VDD monitors: a standard VDD monitor (VDDMON0) and a level-sensitive VDD monitor (VDDMON1). VDDMON0 is primarily intended for setting a higher threshold to allow safe erase or write of Flash memory from firmware. VDDMON1 is used to hold the device in a reset state during power-up and brownout conditions. Note: VDDMON1 is not present in older silicon revisions A and B. Please refer to Section “20.4. VDD Monitors and VDD Ramp Time” on page 211 for more details. When a power-down transition or power irregularity causes VDD to drop below VRST, the power supply monitors (VDDMON0 and VDDMON1) will drive the RST pin low and hold the CIP-51 in a reset state (see Figure 11.2). When VDD returns to a level above VRST, the CIP-51 will be released from the reset state. Note that even though internal data memory contents are not altered by the power-fail reset, it is impossible to determine if VDD dropped below the level required for data retention. If the PORSF flag reads 1, the data may no longer be valid. VDDMON0 is enabled and is selected as a reset source after power-on resets; however its defined state (enabled/disabled) is not altered by any other reset source. For example, if VDDMON0 is disabled by software, and a software reset is performed, VDDMON0 will still be disabled after that reset. VDDMON1 is enabled and is selected as a reset source after power-on reset and any other type of reset. There is no register setting that can disable this level-sensitive VDD monitor as a reset source. To protect the integrity of Flash contents, the VDD monitor (VDDMON0) must be enabled to the higher setting (VDMLVL = '1') and selected as a reset source if software contains routines which erase or write Flash memory. If the VDD monitor is not enabled and set to the higher setting, any erase or write performed on Flash memory will cause a Flash Error device reset. Note: Please refer to Section “20.5. VDD Monitor (VDDMON0) High Threshold Setting” on page 212 for important notes related to the VDD Monitor high threshold setting in older silicon revisions A and B. The VDD monitor (VDDMON0) must be enabled before it is selected as a reset source. Selecting the VDDMON0 as a reset source before it is enabled and stabilized may cause a system reset. The procedure for re-enabling the VDD monitor and configuring the VDD monitor as a reset source is shown below: 1. Enable the VDD monitor (VDMEN bit in VDDMON = 1). 2. Wait for the VDD monitor to stabilize (see Table 2.8 on page 32 for the VDD Monitor turn-on time). Note: This delay should be omitted if software contains routines which write or erase Flash memory. 3. Select the VDD monitor as a reset source (PORSF bit in RSTSRC = 1). See Figure 11.2 for VDD monitor timing; note that the reset delay is not incurred after a VDD monitor reset. See Table 2.8 on page 32 for complete electrical characteristics of the VDD monitor. Note: Software should take care not to inadvertently disable the VDD Monitor (VDDMON0) as a reset source when writing to RSTSRC to enable other reset sources or to trigger a software reset. All writes to RSTSRC should explicitly set PORSF to '1' to keep the VDD Monitor enabled as a reset source. 11.2.1. VDD Monitor Thresholds and Minimum VDD The minimum operating digital supply voltage (VDD) is specified as 2.0 V in Table 2.2 on page 26. The voltage at which the MCU is released from reset (VRST) can be as low as 1.65 V based on the VDD Monitor thresholds that are specified in Table 2.8 on page 32. This could allow code execution during the power-up Rev. 1.4 108 C8051F52x/F52xA/F53x/F53xA ramp or during a brownout condition even when VDD is below the specified minimum of 2.0 V. There are two possible ways to handle this transitional period as described below: If using the on-chip regulator (REG0) at the 2.6 V setting (default), it is recommended that user software set the VDDMON0 threshold to its high setting (VRST-HIGH) as soon as possible after reset by setting the VDMLVL bit to 1 in SFR Definition 11.1 (VDDMON). In this typical configuration, no external hardware or additional software routines are necessary to monitor the VDD level. Note: Please refer to Section “20.5. VDD Monitor (VDDMON0) High Threshold Setting” on page 212 for important notes related to the VDD Monitor high threshold setting in older silicon revisions A and B. If using the on-chip regulator (REG0) at the 2.1 V setting or if directly driving VDD with REG0 disabled, the user system (software/hardware) should monitor VDD at power-on and also during device operation. The two key parameters that can be affected when VDD < 2.0 V are: internal oscillator frequency (Table 2.11 on page 34) and minimum ADC tracking time (Table 2.3 on page 28). SFR Definition 11.1. VDDMON: VDD Monitor Control R/W R R/W R R R R R Reset Value VDMEN VDDSTAT VDMLVL VDM1EN Reserved Reserved Reserved Reserved 1v010000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: Bit7: 0xFF VDMEN: VDD Monitor Enable (VDDMON0). This bit turns the VDD monitor circuit on/off. The VDD Monitor cannot generate system resets until it is also selected as a reset source in register RSTSRC (SFR Definition 11.2). The VDD Monitor can be allowed to stabilize before it is selected as a reset source. Selecting the VDD monitor as a reset source before it has stabilized may generate a system reset. See Table 2.8 on page 32 for the minimum VDD Monitor turn-on time. 0: VDD Monitor Disabled. 1: VDD Monitor Enabled (default). Bit6: VDDSTAT: VDD Status. This bit indicates the current power supply status (VDD Monitor output). 0: VDD is at or below the VDD Monitor (VDDMON0) Threshold. 1: VDD is above the VDD Monitor (VDDMON0) Threshold. Bit5: VDMLVL: VDD Level Select. 0: VDD Monitor (VDDMON0) Threshold is set to VRST-LOW (default). 1: VDD Monitor (VDDMON0) Threshold is set to VRST-HIGH. This setting is required for any system that includes code that writes to and/or erases Flash. Bit4: VDM1EN*: Level-sensitive VDD Monitor Enable (VDDMON1). This bit turns the VDD monitor circuit on/off. If turned on, it is also selected as a reset source, and can generate a system reset. 0: Level-sensitive VDD Monitor Disabled. 1: Level-sensitive VDD Monitor Enabled (default). Bits3–0: RESERVED. Read = Variable. Write = don’t care. *Note: Available only on the C8051F52x-C/F53x-C devices 109 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 11.3. External Reset The external RST pin provides a means for external circuitry to force the device into a reset state. Asserting an active-low signal on the RST pin generates a reset; an external pullup and/or decoupling of the RST pin may be necessary to avoid erroneous noise-induced resets. See Table 2.8 on page 32 for complete RST pin specifications. The PINRSF flag (RSTSRC.0) is set on exit from an external reset. Note: Please refer to Section “20.6. Reset Low Time” on page 212 for restrictions on reset low time in older silicon revisions A and B. 11.4. Missing Clock Detector Reset The Missing Clock Detector (MCD) is a one-shot circuit that is triggered by the system clock. If the system clock remains high or low for more than 100 µs, the one-shot will time out and generate a reset. After a MCD reset, the MCDRSF flag (RSTSRC.2) will read 1, signifying the MCD as the reset source; otherwise, this bit reads 0. Writing a 1 to the MCDRSF bit enables the Missing Clock Detector; writing a 0 disables it. The state of the RST pin is unaffected by this reset. 11.5. Comparator Reset Comparator0 can be configured as a reset source by writing a 1 to the C0RSEF flag (RSTSRC.5). Comparator0 should be enabled and allowed to settle prior to writing to C0RSEF to prevent any turn-on chatter on the output from generating an unwanted reset. The Comparator0 reset is active-low: if the non-inverting input voltage (on CP0+) is less than the inverting input voltage (on CP0-), the device is put into the reset state. After a Comparator0 reset, the C0RSEF flag (RSTSRC.5) will read 1 signifying Comparator0 as the reset source; otherwise, this bit reads 0. The state of the RST pin is unaffected by this reset. 11.6. PCA Watchdog Timer Reset The programmable Watchdog Timer (WDT) function of the Programmable Counter Array (PCA) can be used to prevent software from running out of control during a system malfunction. The PCA WDT function can be enabled or disabled by software as described in Section “19.3. Watchdog Timer Mode” on page 203; the WDT is enabled and clocked by SYSCLK / 12 following any reset. If a system malfunction prevents user software from updating the WDT, a reset is generated and the WDTRSF bit (RSTSRC.5) is set to 1. The state of the RST pin is unaffected by this reset. 11.7. Flash Error Reset If a Flash read/write/erase or program read targets an illegal address, a system reset is generated. This may occur due to any of the following:      A Flash write or erase is attempted above user code space. This occurs when PSWE is set to 1 and a MOVX write operation targets an address above the Lock Byte address. A Flash read is attempted above user code space. This occurs when a MOVC operation targets an address above the Lock Byte address. A program read is attempted above user code space. This occurs when user code attempts to branch to an address above the Lock Byte address. A Flash read, write or erase attempt is restricted due to a Flash security setting (see Section “12.4. Security Options” on page 117). A Flash write or erase is attempted while the VDD Monitor (VDDMON0) is disabled or not set to its high threshold setting. The FERROR bit (RSTSRC.6) is set following a Flash error reset. The state of the RST pin is unaffected by this reset. Rev. 1.4 110 C8051F52x/F52xA/F53x/F53xA 11.8. Software Reset Software may force a reset by writing a 1 to the SWRSF bit (RSTSRC.4). The SWRSF bit will read 1 following a software forced reset. The state of the RST pin is unaffected by this reset. 111 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 11.2. RSTSRC: Reset Source R/W — Bit7 R R/W FERROR C0RSEF Bit6 Bit5 R/W SWRSF Bit4 R R/W WDTRSF MCDRSF Bit3 Bit2 R/W R Reset Value PORSF PINRSF Variable Bit1 Bit0 SFR Address: 0xEF Note: Software should avoid read modify write instructions when writing values to RSTSRC. Bit7: Bit6: Bit5: Bit4: Bit3: Bit2: Bit1: Bit0: UNUSED. Read = 1, Write = don't care. FERROR: Flash Error Indicator. 0: Source of last reset was not a Flash read/write/erase error. 1: Source of last reset was a Flash read/write/erase error. C0RSEF: Comparator0 Reset Enable and Flag. 0: Read: Source of last reset was not Comparator0. Write: Comparator0 is not a reset source. 1: Read: Source of last reset was Comparator0. Write: Comparator0 is a reset source (active-low). SWRSF: Software Reset Force and Flag. 0: Read: Source of last reset was not a write to the SWRSF bit. Write: No Effect. 1: Read: Source of last reset was a write to the SWRSF bit. Write: Forces a system reset. WDTRSF: Watchdog Timer Reset Flag. 0: Source of last reset was not a WDT timeout. 1: Source of last reset was a WDT timeout. MCDRSF: Missing Clock Detector Flag. 0: Read: Source of last reset was not a Missing Clock Detector timeout. Write: Missing Clock Detector disabled. 1: Read: Source of last reset was a Missing Clock Detector timeout. Write: Missing Clock Detector enabled; triggers a reset if a missing clock condition is detected. PORSF: Power-On Reset Force and Flag. This bit is set anytime a power-on reset occurs. Writing this bit enables/disables the VDD monitor (VDDMON0) as a reset source. Note: writing 1 to this bit before the VDD monitor is enabled and stabilized may cause a system reset. See register VDDMON (SFR Definition 11.1) 0: Read: Last reset was not a power-on or VDD monitor reset. Write: VDD monitor (VDDMON0) is not a reset source. 1: Read: Last reset was a power-on or VDD monitor reset; all other reset flags indeterminate. Write: VDD monitor (VDDMON0) is a reset source. PINRSF: HW Pin Reset Flag. 0: Source of last reset was not RST pin. 1: Source of last reset was RST pin. Rev. 1.4 112 C8051F52x/F52xA/F53x/F53xA 12. Flash Memory On-chip, re-programmable Flash memory is included for program code and non-volatile data storage. The Flash memory can be programmed in-system through the C2 interface or by software using the MOVX write instruction. Once cleared to logic 0, a Flash bit must be erased to set it back to logic 1. Flash bytes would typically be erased (set to 0xFF) before being reprogrammed. The write and erase operations are automatically timed by hardware for proper execution; data polling to determine the end of the write/erase operations is not required. Code execution is stalled during Flash write/erase operations. Refer to Table 2.9 on page 33 for complete Flash memory electrical characteristics. 12.1. Programming The Flash Memory The simplest means of programming the Flash memory is through the C2 interface using programming tools provided by Silicon Laboratories or a third party vendor. This is the only means for programming a non-initialized device. For details on the C2 commands to program Flash memory, see Section “21. C2 Interface” on page 214. To protect the integrity of Flash contents, the VDD monitor must be enabled to the higher setting (VDMLVL = '1') and selected as a reset source if software contains routines which erase or write Flash memory. If the VDD monitor is not enabled, any erase or write performed on Flash memory will cause a Flash Error device reset. See Section “11.2. Power-Fail Reset / VDD Monitors (VDDMON0 and VDDMON1)” on page 108 for more information regarding the VDD monitor and the high threshold setting. The VDD monitor must be enabled before it is selected as a reset source. Selecting the VDD monitor as a reset source before it is enabled and stabilized may cause a system reset. The procedure for reenabling the VDD monitor and configuring the VDD monitor as a reset source is shown below: 1. Enable the VDD monitor (VDMEN bit in VDDMON = 1). 2. Wait for the VDD monitor to stabilize (see Table 2.8 on page 32 for the VDD Monitor turn-on time). Note: This delay should be omitted if software contains routines which write or erase Flash memory. 3. Select the VDD monitor as a reset source (PORSF bit in RSTSRC = 1). Note: 8-bit MOVX instructions cannot be used to erase or write to Flash memory at addresses higher than 0x00FF. Important Note: For –I (industrial Grade) parts, flash should be programmed (erase/write) at a minimum temperature of 0 °C for reliable flash operation across the entire temperature range of –40 to +125 °C. This minimum programming temperature does not apply to –A (Automotive Grade) parts. 12.1.1. Flash Lock and Key Functions Flash writes and erases by user software are protected with a lock and key function. The Flash Lock and Key Register (FLKEY) must be written with the correct key codes, in sequence, before Flash operations may be performed. The key codes are: 0xA5, 0xF1. The timing does not matter, but the codes must be written in order. If the key codes are written out of order, or the wrong codes are written, Flash writes and erases will be disabled until the next system reset. Flash writes and erases will also be disabled if a Flash write or erase is attempted before the key codes have been written properly. The Flash lock resets after each write or erase; the key codes must be written again before a following Flash operation can be performed. The FLKEY register is detailed in SFR Definition 12.2. Rev. 1.4 113 C8051F52x/F52xA/F53x/F53xA 12.1.2. Flash Erase Procedure The Flash memory can be programmed by software using the MOVX write instruction with the address and data byte to be programmed provided as normal operands. Before writing to Flash memory using MOVX, Flash write operations must be enabled by: (1) setting the PSWE Program Store Write Enable bit (PSCTL.0) to logic 1 (this directs the MOVX writes to target Flash memory); and (2) Writing the Flash key codes in sequence to the Flash Lock register (FLKEY). The PSWE bit remains set until cleared by software. A write to Flash memory can clear bits to logic 0 but cannot set them; only an erase operation can set bits to logic 1 in Flash. A byte location to be programmed should be erased before a new value is written. The Flash memory is organized in 512-byte pages. The erase operation applies to an entire page (setting all bytes in the page to 0xFF). To erase an entire 512-byte page, perform the following steps: 1. Disable interrupts (recommended). 2. Write the first key code to FLKEY: 0xA5. 3. Write the second key code to FLKEY: 0xF1. 4. Set the PSEE bit (register PSCTL). 5. Set the PSWE bit (register PSCTL). 6. Using the MOVX instruction, write a data byte to any location within the 512-byte page to be erased. 7. Clear the PSWE and PSEE bits. 8. Re-enable interrupts. 12.1.3. Flash Write Procedure Flash bytes are programmed by software with the following sequence: 1. Disable interrupts. 2. Write the first key code to FLKEY: 0xA5. 3. Write the second key code to FLKEY: 0xF1. 4. Set the PSWE bit (register PSCTL). 5. Clear the PSEE bit (register PSCTL). 6. Using the MOVX instruction, write a single data byte to the desired location within the 512-byte sector. 7. Clear the PSWE bit. 8. Re-enable interrupts. Steps 2–7 must be repeated for each byte to be written. After Flash writes are complete, PSWE should be cleared so that MOVX instructions do not target program memory. 114 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 12.2. Flash Write and Erase Guidelines Any system which contains routines which write or erase Flash memory from software involves some risk that the write or erase routines will execute unintentionally if the CPU is operating outside its specified operating range of VDD, system clock frequency, or temperature. This accidental execution of Flash modifying code can result in alteration of Flash memory contents causing a system failure that is only recoverable by re-Flashing the code in the device. The following guidelines are recommended for any system which contains routines which write or erase Flash from code. 12.2.1. VDD Maintenance and the VDD monitor 1. If the system power supply is subject to voltage or current "spikes," add sufficient transient protection devices to the power supply to ensure that the supply voltages listed in the Absolute Maximum Ratings table are not exceeded. 2. Make certain that the maximum VDD ramp time specification (if applicable) is met. See Section 20.4 on page 211 for more details on VDD ramp time. If the system cannot meet this ramp time specification, then add an external VDD brownout circuit to the RST pin of the device that holds the device in reset until VDD reaches the minimum specified VDD and re-asserts RST if VDD drops belowthat level. VDD (min) is specified in Table 2.2 on page 26. 3. Enable the on-chip VDD monitor (VDDMON0) and enable it as a reset source as early in code as possible. This should be the first set of instructions executed after the Reset Vector. For C-based systems, this will involve modifying the startup code added by the C compiler. See your compiler documentation for more details. Make certain that there are no delays in software between enabling the VDD monitor (VDDMON0) and enabling it as a reset source. Code examples showing this can be found in “AN201: Writing to Flash from Firmware", available from the Silicon Laboratories web site. 4. As an added precaution, explicitly enable the VDD monitor (VDDMON0) and enable the VDD monitor as a reset source inside the functions that write and erase Flash memory. The VDD monitor enable instructions should be placed just after the instruction to set PSWE to a 1, but before the Flash write or erase operation instruction. 5. Make certain that all writes to the RSTSRC (Reset Sources) register use direct assignment operators and explicitly DO NOT use the bit-wise operators (such as AND or OR). For example, "RSTSRC = 0x02" is correct. "RSTSRC |= 0x02" is incorrect. 6. Make certain that all writes to the RSTSRC register explicitly set the PORSF bit to a 1. Areas to check are initialization code which enables other reset sources, such as the Missing Clock Detector or Comparator, for example, and instructions which force a Software Reset. A global search on "RSTSRC" can quickly verify this. 12.2.2. PSWE Maintenance 1. Reduce the number of places in code where the PSWE bit (PSCTL.0) is set to a 1. There should be exactly one routine in code that sets PSWE to a 1 to write Flash bytes and one routine in code that sets PSWE and PSEE both to a 1 to erase Flash pages. 2. Minimize the number of variable accesses while PSWE is set to a 1. Handle pointer address updates and loop variable maintenance outside the "PSWE = 1;... PSWE = 0;" area. Code examples showing this can be found in “AN201: Writing to Flash from Firmware," available from the Silicon Laboratories web site. 3. Disable interrupts prior to setting PSWE to a 1 and leave them disabled until after PSWE has been reset to '0'. Any interrupts posted during the Flash write or erase operation will be serviced in priority order after the Flash operation has been completed and interrupts have been re-enabled by software. 4. Make certain that the Flash write and erase pointer variables are not located in XRAM. See your compiler documentation for instructions regarding how to explicitly locate variables in different memory areas. Rev. 1.4 115 C8051F52x/F52xA/F53x/F53xA 5. Add address bounds checking to the routines that write or erase Flash memory to ensure that a routine called with an illegal address does not result in modification of the Flash. 12.2.3. System Clock 1. If operating from an external crystal, be advised that crystal performance is susceptible to electrical interference and is sensitive to layout and to changes in temperature. If the system is operating in an electrically noisy environment, use the internal oscillator or use an external CMOS clock. 2. If operating from the external oscillator, switch to the internal oscillator during Flash write or erase operations. The external oscillator can continue to run, and the CPU can switch back to the external oscillator after the Flash operation has completed. Additional Flash recommendations and example code can be found in application note “AN201: Writing to Flash from Firmware," available from the Silicon Laboratories website. 116 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 12.3. Non-volatile Data Storage The Flash memory can be used for non-volatile data storage as well as program code. This allows data such as calibration coefficients to be calculated and stored at run time. Data is written using the MOVX write instruction and read using the MOVC instruction. Note: MOVX read instructions always target XRAM. Note: See Section “12.1. Programming The Flash Memory” on page 113 for minimum VDD and temperature requirements for flash erase and write operations. 12.4. Security Options The CIP-51 provides security options to protect the Flash memory from inadvertent modification by software as well as to prevent the viewing of proprietary program code and constants. The Program Store Write Enable (bit PSWE in register PSCTL) and the Program Store Erase Enable (bit PSEE in register PSCTL) bits protect the Flash memory from accidental modification by software. PSWE must be explicitly set to 1 before software can modify the Flash memory; both PSWE and PSEE must be set to 1 before software can erase Flash memory. Additional security features prevent proprietary program code and data constants from being read or altered across the C2 interface. A Security Lock Byte located at the last byte of Flash user space offers protection of the Flash program memory from access (reads, writes, or erases) by unprotected code or the C2 interface. The Flash security mechanism allows the user to lock n 512-byte Flash pages, starting at page 0 (addresses 0x0000 to 0x01FF), where n is the 1’s complement number represented by the Security Lock Byte. Note that the page containing the Flash Security Lock Byte is unlocked when no other Flash pages are locked (all bits of the Lock Byte are 1) and locked when any other Flash pages are locked (any bit of the Lock Byte is 0). See example below. Security Lock Byte: 1’s Complement: Flash pages locked: 11111101b 00000010b 3 (First two Flash pages + Lock Byte Page) Addresses locked: 0x0000 to 0x03FF (first two Flash pages) 0x1C00 to 0x1DFF in ’F520/0A/1/1A and ’F530/0A/1/1A 0x0C00 to 0x0FFF in ’F523/3A/4/4A and ’F533/3A/4/4A and 0x0600 to 0x07FF in ’F526/6A/7/7A and ’F536/6A/7/7A 'F523/3A/4/4A and 'F533/3A/4/4A 'F520/0A/1/1A and 'F530/0A/1/1A 'F526/6A/7/7A and 'F536/6A/7/7A Reserved Reserved Reserved 0x1E00 Locked when any other Flash pages are locked Access limit set according to the Flash security lock byte Lock Byte 0x1DFF Lock Byte 0x0FFF Lock Byte 0x07FF 0x1DFE 0x0FFE 0x07FE 0x1C00 0x0E00 0x0600 Flash memory organized Unlocked Flash Pages in 512-byte pages Unlocked Flash Pages Unlocked Flash Pages 0x0000 0x0000 0x0000 Figure 12.1. Flash Program Memory Map Rev. 1.4 117 C8051F52x/F52xA/F53x/F53xA The level of Flash security depends on the Flash access method. The three Flash access methods that can be restricted are reads, writes, and erases from the C2 debug interface, user firmware executing on unlocked pages, and user firmware executing on locked pages. Table 12.1 summarizes the Flash security features of the ’F52x/’F52xA/’F53x/’F53xA devices. Table 12.1. Flash Security Summary Action C2 Debug Interface User Firmware executing from: an unlocked page a locked page Permitted Permitted Permitted Not Permitted Flash Error Reset Permitted Read or Write page containing Lock Byte (if no pages are locked) Permitted Permitted Permitted Read or Write page containing Lock Byte (if any page is locked) Not Permitted Flash Error Reset Permitted Read contents of Lock Byte (if no pages are locked) Permitted Permitted Permitted Read contents of Lock Byte (if any page is locked) Not Permitted Flash Error Reset Permitted Read, Write or Erase unlocked pages (except page with Lock Byte) Read, Write or Erase locked pages (except page with Lock Byte) Erase page containing Lock Byte (if no pages are locked) Permitted Flash Error Reset Flash Error Reset C2 Device Erase Only Flash Error Reset Flash Error Reset Lock additional pages (change 1s to 0s in the Lock Byte) Not Permitted Flash Error Reset Flash Error Reset Unlock individual pages (change 0s to 1s in the Lock Byte) Not Permitted Flash Error Reset Flash Error Reset Read, Write or Erase Reserved Area Not Permitted Flash Error Reset Flash Error Reset Erase page containing Lock Byte—Unlock all pages (if any page is locked) C2 Device Erase—Erases all Flash pages including the page containing the Lock Byte. Flash Error Reset—Not permitted; Causes Flash Error Device Reset (FERROR bit in RSTSRC is 1 after reset). - All prohibited operations that are performed via the C2 interface are ignored (do not cause device reset). - Locking any Flash page also locks the page containing the Lock Byte. - Once written to, the Lock Byte cannot be modified except by performing a C2 Device Erase. - If user code writes to the Lock Byte, the Lock does not take effect until the next device reset. 118 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 12.1. PSCTL: Program Store R/W Control R R R R R R R/W R/W Reset Value — — — — — — PSEE PSWE 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0x8F Bits7–2: UNUSED: Read = 000000b, Write = don’t care. Bit1: PSEE: Program Store Erase Enable Setting this bit (in combination with PSWE) allows an entire page of Flash program memory to be erased. If this bit is logic 1 and Flash writes are enabled (PSWE is logic 1), a write to Flash memory using the MOVX instruction will erase the entire page that contains the location addressed by the MOVX instruction. The value of the data byte written does not matter. 0: Flash program memory erasure disabled. 1: Flash program memory erasure enabled. Bit0: PSWE: Program Store Write Enable Setting this bit allows writing a byte of data to the Flash program memory using the MOVX write instruction. The Flash location should be erased before writing data. 0: Writes to Flash program memory disabled. 1: Writes to Flash program memory enabled; the MOVX write instruction targets Flash memory. Note: See Section “12.1. Programming The Flash Memory” on page 113 for minimum VDD and temperature requirements for flash erase and write operations. SFR Definition 12.2. FLKEY: Flash Lock and Key R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xB7 Bits7–0: FLKEY: Flash Lock and Key Register Write: This register provides a lock and key function for Flash erasures and writes. Flash writes and erases are enabled by writing 0xA5 followed by 0xF1 to the FLKEY register. Flash writes and erases are automatically disabled after the next write or erase is complete. If any writes to FLKEY are performed incorrectly, or if a Flash write or erase operation is attempted while these operations are disabled, the Flash will be permanently locked from writes or erasures until the next device reset. If an application never writes to Flash, it can intentionally lock the Flash by writing a non-0xA5 value to FLKEY from software. Read: When read, bits 1–0 indicate the current Flash lock state. 00: Flash is write/erase locked. 01: The first key code has been written (0xA5). 10: Flash is unlocked (writes/erases allowed). 11: Flash writes/erases disabled until the next reset. Rev. 1.4 119 C8051F52x/F52xA/F53x/F53xA 13. Port Input/Output Digital and analog resources are available through up to 16 I/O pins. Port pins are organized as two or one byte-wide Ports. Each of the Port pins can be defined as general-purpose I/O (GPIO) or analog input/output; Port pins P0.0 - P2.7 can be assigned to one of the internal digital resources as shown in Figure 13.3. The designer has complete control over which functions are assigned, limited only by the number of physical I/O pins. This resource assignment flexibility is achieved through the use of a Priority Crossbar Decoder. Note that the state of a Port I/O pin can always be read in the corresponding Port latch, regardless of the Crossbar settings. The Crossbar assigns the selected internal digital resources to the I/O pins based on the peripheral priority order of the Priority Decoder (Figure 13.3 and Figure 13.4). The registers XBR0 and XBR1, defined in SFR Definition 13.1 and SFR Definition 13.2, are used to select internal digital functions. Port I/O pins are 5.25 V tolerant over the operating range of VREGIN. Figure 13.2 shows the Port cell circuit. The Port I/O cells are configured as either push-pull or open-drain in the Port Output Mode registers (PnMDOUT, where n = 0,1). Complete Electrical Specifications for Port I/O are given in Table 2.10 on page 33. P0MASK, P0MATCH P1MASK, P1MATCH Registers XBR0, XBR1, PnSKIP Registers 2 UART 4 (Internal Digital Signals) SPI 8 2 LIN CP0 Outputs 8 7 T0, T1 P0.0 P0.7 2 SYSCLK P1 I/O Cells P1.0 P1.7 2 P1.0–1.7 and P0.7 available on C8051F53x/ C8051F53xA parts 8 P0 P0 I/O Cells Digital Crossbar PCA (Port Latches) Lowest Priority PnMDOUT, PnMDIN Registers Priority Decoder Highest Priority (P0.0-P0.7) 8 P1 (P1.0-P1.7*) Figure 13.1. Port I/O Functional Block Diagram Rev. 1.4 120 C8051F52x/F52xA/F53x/F53xA /WEAK-PULLUP VREGIN PUSH-PULL /PORT-OUTENABLE VREGIN (WEAK) PORT PAD PORT-OUTPUT GND Analog Select ANALOG INPUT PORT-INPUT Figure 13.2. Port I/O Cell Block Diagram 121 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 13.1. Priority Crossbar Decoder The Priority Crossbar Decoder (Figure 13.3) assigns a priority to each I/O function, starting at the top with UART0. When a digital resource is selected, the least-significant unassigned Port pin is assigned to that resource (excluding UART0, which will be assigned to pins P0.4 and P0.5). If a Port pin is assigned, the Crossbar skips that pin when assigning the next selected resource. Additionally, the Crossbar will skip Port pins whose associated bits in the PnSKIP registers are set. The PnSKIP registers allow software to skip Port pins that are to be used for analog input, dedicated functions, or GPIO. 1 2 3 4 5 6 7 0 TX0 CNVSTR VREF TSSOP 20 and QFN 20 PIN I/O 0 XTAL2 P1 XTAL1 P0 SF Signals 1 2 3 4 5 6 7 C8051F53xA/F53x-C devices RX0 TX0 C8051F53x devices RX0 SCK MISO MOSI NSS* LIN-TX LIN_RX CP0 CP0A /SYSCLK CEX0 CEX1 CEX2 ECI T0 T1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 P1SKIP[0:7] P0SKIP[0:7] Port pin potentially assignable to peripheral SF Signals Special Function Signals are not assigned by the crossbar. When these signals are enabled, the Crossbar must be manually configured to skip their corresponding port pins. Note: 4-Wire SPI Only. Figure 13.3. Crossbar Priority Decoder with No Pins Skipped (TSSOP 20 and QFN 20) Important Note on Crossbar Configuration: If a Port pin is claimed by a peripheral without use of the Crossbar, its corresponding PnSKIP bit should be set. This applies to P1.0 and/or P0.7 (F53x/F53xA) or P0.2 and/or P0.3 (F52x/F52xA) for the external oscillator, P0.0 for VREF, P1.2 (F53x/F53xA) or P0.5 Rev. 1.4 122 C8051F52x/F52xA/F53x/F53xA (F52x/F52xA) for the external CNVSTR signal, and any selected ADC or comparator inputs. The Crossbar skips selected pins as if they were already assigned, and moves to the next unassigned pin. Figure 13.3 shows the Crossbar Decoder priority with no Port pins skipped (P0SKIP, P1SKIP); Figure 13.4 shows the Crossbar Decoder priority with the XTAL1 (P1.0) and XTAL2 (P1.1) pins skipped (P1SKIP = 0x03). Important Note on UART Pins: On C8051F52xA/F52x-C/F53xA/F53x-C devices, the UART pins must be skipped if the UART is enabled in order for peripherals to appear on port pins beyond the UART on the crossbar. For example, with the SPI and UART enabled on the crossbar with the SPI on P1.0-P1.3, the UART pins must be skipped using P0SKIP for the SPI pins to appear correctly. 0 PIN I/O 1 2 3 4 5 6 7 0 CNVSTR TSSOP 20 and QFN 20 VREF SF Signals XTAL2 P1 XTAL1 P0 1 TX0 2 3 4 5 6 7 C8051F53xA/F53x-C devices RX0 TX0 C8051F53x devices RX0 SCK MISO MOSI NSS* LIN-TX LIN-RX CP0 CP0A /SYSCLK CEX0 CEX1 CEX2 ECI T0 T1 0 0 0 0 0 0 0 1 1 P0SKIP[0:7] = 0x80 0 0 0 0 0 0 0 P1SKIP[0:7] = 0x01 Port pin potentially assignable to peripheral SF Signals Special Function Signals are not assigned by the crossbar. When these signals are enabled, the Crossbar must be manually configured to skip their corresponding port pins. Note: 4-Wire SPI Only. Figure 13.4. Crossbar Priority Decoder with Crystal Pins Skipped (TSSOP 20 and QFN 20) 123 Rev. 1.4 0 1 2 3 CNVSTR XTAL2 PIN I/O XTAL1 SF Signals DFN10 VREF C8051F52x/F52xA/F53x/F53xA 4 5 TX0 C8051F52xA/F52x-C devices RX0 TX0 C8051F52x devices RX0 SCK MISO MOSI NSS* LIN-TX LIN_RX CP0 CP0A /SYSCLK CEX0 CEX1 CEX2 ECI T0 T1 0 0 0 0 0 0 P0SKIP[0:5] Port pin potentially assignable to peripheral SF Signals Special Function Signals are not assigned by the crossbar. When these signals are enabled, the Crossbar must be manually configured to skip their corresponding port pins. Note: 4-Wire SPI Only. Figure 13.5. Crossbar Priority Decoder with No Pins Skipped (DFN 10) Rev. 1.4 124 C8051F52x/F52xA/F53x/F53xA 1 2 3 CNVSTR 0 XTAL2 PIN I/O XTAL1 SF Signals DFN 10 VREF P0 4 5 TX0 C8051F52xA/F52x-C devices RX0 TX0 C8051F52x devices RX0 SCK MISO MOSI NSS* LIN-TX LIN-RX CP0 CP0A /SYSCLK CEX0 CEX1 CEX2 ECI T0 T1 0 1 1 0 0 0 P0SKIP[0:5] = 0x06 Port pin potentially assignable to peripheral SF Signals Special Function Signals are not assigned by the crossbar. When these signals are enabled, the Crossbar must be manually configured to skip their corresponding port pins. Note: 4-Wire SPI Only. Figure 13.6. Crossbar Priority Decoder with Some Pins Skipped (DFN 10) Registers XBR0 and XBR1 are used to assign the digital I/O resources to the physical I/O Port pins. Note that when the SMBus is selected, the Crossbar assigns both pins associated with the SMBus (SDA and SCL); when the UART is selected, the Crossbar assigns both pins associated with the UART (TX and RX). UART0 pin assignments are fixed for bootloading purposes: UART TX0 is always assigned to P0.3 or P0.4*; UART RX0 is always assigned to P0.4 or P0.5*. Standard Port I/Os appear contiguously starting at P0.0 after prioritized functions and skipped pins are assigned. Note: Refer to Section “20. Device Specific Behavior” on page 210. 125 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA Important Note: The SPI can be operated in either 3-wire or 4-wire modes, depending on the state of the NSSMD1–NSSMD0 bits in register SPI0CN. According to the SPI mode, the NSS signal may or may not be routed to a Port pin. 13.2. Port I/O Initialization Port I/O initialization consists of the following steps: 1. Select the input mode (analog or digital) for all Port pins, using the Port Input Mode register (PnMDIN). 2. Select the output mode (open-drain or push-pull) for all Port pins, using the Port Output Mode register (PnMDOUT). 3. Select any pins to be skipped by the I/O Crossbar using the Port Skip registers (PnSKIP). 4. Assign Port pins to desired peripherals using the XBRn registers. 5. Enable the Crossbar (XBARE = 1). All Port pins must be configured as either analog or digital inputs. Any pins to be used as Comparator or ADC inputs should be configured as an analog inputs. When a pin is configured as an analog input, its weak pullup, digital driver, and digital receiver are disabled. This process saves power and reduces noise on the analog input. Pins configured as digital inputs may still be used by analog peripherals; however, this practice is not recommended. Additionally, all analog input pins should be configured to be skipped by the Crossbar (accomplished by setting the associated bits in PnSKIP). Port input mode is set in the PnMDIN register, where a 1 indicates a digital input, and a 0 indicates an analog input. All pins default to digital inputs on reset. See SFR Definition 13.4 for the PnMDIN register details. Important Note: Port 0 and Port 1 pins are 5.25 V tolerant across the operating range of VREGIN. The output driver characteristics of the I/O pins are defined using the Port Output Mode registers (PnMDOUT). Each Port Output driver can be configured as either open drain or push-pull. This selection is required even for the digital resources selected in the XBRn registers, and is not automatic. When the WEAKPUD bit in XBR1 is 0, a weak pullup is enabled for all Port I/O configured as open-drain. WEAKPUD does not affect the push-pull Port I/O. Furthermore, the weak pullup is turned off on an output that is driving a 0 and for pins configured for analog input mode to avoid unnecessary power dissipation. Registers XBR0 and XBR1 must be loaded with the appropriate values to select the digital I/O functions required by the design. Setting the XBARE bit in XBR1 to 1 enables the Crossbar. Until the Crossbar is enabled, the external pins remain as standard Port I/O (in input mode), regardless of the XBRn Register settings. For given XBRn Register settings, one can determine the I/O pin-out using the Priority Decode Table. The Crossbar must be enabled to use Port pins as standard Port I/O in output mode. Port output drivers are disabled while the Crossbar is disabled. Rev. 1.4 126 C8051F52x/F52xA/F53x/F53xA SFR Definition 13.1. XBR0: Port I/O Crossbar Register 0 R/W R/W R/W R/W R/W R/W R/W R/W Reset Value - - CP0AE CP0E SYSCKE LINE SPI0E URT0E 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: Bit7–6: Bit5: Bit4: Bit3: Bit2: Bit1: Bit0: RESERVED. Read = 00b; Must write 00b. CP0AE: Comparator0 Asynchronous Output Enable 0: Asynchronous CP0 unavailable at Port pin. 1: Asynchronous CP0 routed to Port pin. CP0E: Comparator0 Output Enable 0: CP0 unavailable at Port pin. 1: CP0 routed to Port pin. SYSCKE: /SYSCLK Output Enable 0: /SYSCLK unavailable at Port pin. 1: /SYSCLK output routed to Port pin. LINE. Lin Output Enable SPI0E: SPI I/O Enable 0: SPI I/O unavailable at Port pins. 1: SPI I/O routed to Port pins. Note that the SPI can be assigned either 3 or 4 GPIO pins. URT0E: UART I/O Output Enable 0: UART I/O unavailable at Port pin. 1: UART TX0, RX0 routed to Port pins (P0.3 and P0.4) or (P0.4 and P0.5).* Note: Refer to Section “20. Device Specific Behavior” on page 210. 127 0xE1 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 13.2. XBR1: Port I/O Crossbar Register 1 R/W R/W WEAKPUD XBARE Bit7 Bit6 R/W R/W R/W R/W T1E T0E ECIE Reserved Bit5 Bit4 Bit3 Bit2 R/W R/W PCA0ME Bit1 Reset Value 00000000 Bit0 SFR Address: 0xE2 Bit7: WEAKPUD: Port I/O Weak Pullup Disable. 0: Weak Pullups enabled (except for Ports whose I/O are configured as analog input). 1: Weak Pullups disabled. Bit6: XBARE: Crossbar Enable. 0: Crossbar disabled. 1: Crossbar enabled. Bit5: T1E: T1 Enable 0: T1 unavailable at Port pin. 1: T1 routed to Port pin. Bit4: T0E: T0 Enable 0: T0 unavailable at Port pin. 1: T0 routed to Port pin. Bit3: ECIE: PCA0 External Counter Input Enable 0: ECI unavailable at Port pin. 1: ECI routed to Port pin. Bit2: Reserved. Must Write 0b. Bits1–0: PCA0ME: PCA Module I/O Enable Bits. 00: All PCA I/O unavailable at Port pins. 01: CEX0 routed to Port pin. 10: CEX0, CEX1 routed to Port pins. 11: CEX0, CEX1, CEX2 routed to Port pins. 13.3. General Purpose Port I/O Port pins that remain unassigned by the Crossbar and are not used by analog peripherals can be used for general purpose I/O. Ports P0–P1 are accessed through corresponding special function registers (SFRs) that are both byte addressable and bit addressable. When writing to a Port, the value written to the SFR is latched to maintain the output data value at each pin. When reading, the logic levels of the Port's input pins are returned regardless of the XBRn settings (i.e., even when the pin is assigned to another signal by the Crossbar, the Port register can always read its corresponding Port I/O pin). The exception to this is the execution of the read-modify-write instructions that target a Port Latch register as the destination. The read-modify-write instructions when operating on a Port SFR are the following: ANL, ORL, XRL, JBC, CPL, INC, DEC, DJNZ and MOV, CLR or SETB, when the destination is an individual bit in a Port SFR. For these instructions, the value of the latch register (not the pin) is read, modified, and written back to the SFR. Rev. 1.4 128 C8051F52x/F52xA/F53x/F53xA In addition to performing general purpose I/O, P0 and P1 can generate a port match event if the logic levels of the Port’s input pins match a software controlled value. A port match event is generated if (P0 & P0MASK) does not equal (P0MATCH & P0MASK) or if (P1 & P1MASK) does not equal (P1MATCH & P1MASK). This allows Software to be notified if a certain change or pattern occurs on P0 or P1 input pins regardless of the XBRn settings. A port match event can cause an interrupt if EMAT (EIE2.1) is set to 1 or cause the internal oscillator to awaken from SUSPEND mode. See Section “14.1.1. Internal Oscillator Suspend Mode” on page 136 for more information. SFR Definition 13.3. P0: Port0 R/W R/W R/W R/W R/W R/W R/W R/W Reset Value P0.7 P0.6 P0.5 P0.4 P0.3 P0.2 P0.1 P0.0 11111111 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Bit Addressable SFR Address: 0x80 Bits7–0: P0.[7:0] Write - Output appears on I/O pins per Crossbar Registers. 0: Logic Low Output. 1: Logic High Output (high impedance if corresponding P0MDOUT.n bit = 0). Read - Always reads 0 if selected as analog input in register P0MDIN. Directly reads Port pin when configured as digital input. 0: P0.n pin is logic low. 1: P0.n pin is logic high. SFR Definition 13.4. P0MDIN: Port0 Input Mode R/W R/W R/W R/W R/W R/W R/W R/W Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Reset Value 11111111 SFR Address: 0xF1 Bits7–0: Analog Input Configuration Bits for P0.7–P0.0 (respectively). Port pins configured as analog inputs have their weak pullup, digital driver, and digital receiver disabled. 0: Corresponding P0.n pin is configured as an analog input. 1: Corresponding P0.n pin is not configured as an analog input. 129 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 13.5. P0MDOUT: Port0 Output Mode R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xA4 Bits7–0: Output Configuration Bits for P0.7–P0.0 (respectively): ignored if corresponding bit in register P0MDIN is logic 0. 0: Corresponding P0.n Output is open-drain. 1: Corresponding P0.n Output is push-pull. Note: When SDA and SCL appear on any of the Port I/O, each are open-drain regardless of the value of P0MDOUT. SFR Definition 13.6. P0SKIP: Port0 Skip R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xD4 Bits7–0: P0SKIP[7:0]: Port0 Crossbar Skip Enable Bits. These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar. 0: Corresponding P0.n pin is not skipped by the Crossbar. 1: Corresponding P0.n pin is skipped by the Crossbar. Rev. 1.4 130 C8051F52x/F52xA/F53x/F53xA SFR Definition 13.7. P0MAT: Port0 Match R/W R/W R/W R/W R/W R/W R/W R/W Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Reset Value 11111111 SFR Address: 0xD7 Bits7–0: P0MAT[7:0]: Port0 Match Value. These bits control the value that unmasked P0 Port pins are compared against. A Port Match event is generated if (P0 & P0MASK) does not equal (P0MAT & P0MASK). SFR Definition 13.8. P0MASK: Port0 Mask R/W R/W R/W R/W R/W R/W R/W R/W Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Reset Value 00000000 SFR Address: Bits7–0: P0MASK[7:0]: Port0 Mask Value. These bits select which Port pins will be compared to the value stored in P0MAT. 0: Corresponding P0.n pin is ignored and cannot cause a Port Match event. 1: Corresponding P0.n pin is compared to the corresponding bit in P0MAT. 131 Rev. 1.4 0xC7 C8051F52x/F52xA/F53x/F53xA SFR Definition 13.9. P1: Port1 R/W R/W R/W R/W R/W R/W R/W R/W Reset Value P1.7 P1.6 P1.5 P1.4 P1.3 P1.2 P1.1 P1.0 11111111 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Bit Addressable SFR Address: 0x90 Bits7–0: P1.[7:0] Write - Output appears on I/O pins per Crossbar Registers. 0: Logic Low Output. 1: Logic High Output (high impedance if corresponding P1MDOUT.n bit = 0). Read - Always reads 0 if selected as analog input in register P1MDIN. Directly reads Port pin when configured as digital input. 0: P1.n pin is logic low. 1: P1.n pin is logic high. SFR Definition 13.10. P1MDIN: Port1 Input Mode R/W R/W R/W R/W R/W R/W R/W R/W Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Reset Value 11111111 SFR Address: 0xF2 Bits7–0: Analog Input Configuration Bits for P1.7–P1.0 (respectively). Port pins configured as analog inputs have their weak pullup, digital driver, and digital receiver disabled. 0: Corresponding P1.n pin is configured as an analog input. 1: Corresponding P1.n pin is not configured as an analog input. Rev. 1.4 132 C8051F52x/F52xA/F53x/F53xA SFR Definition 13.11. P1MDOUT: Port1 Output Mode R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xA5 Bits7–0: Output Configuration Bits for P1.7–P1.0 (respectively): ignored if corresponding bit in register P1MDIN is logic 0. 0: Corresponding P1.n Output is open-drain. 1: Corresponding P1.n Output is push-pull. Note: When SDA and SCL appear on any of the Port I/O, each are open-drain regardless of the value of P0MDOUT. SFR Definition 13.12. P1SKIP: Port1 Skip R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xD5 Bits7–0: P1SKIP[7:0]: Port1 Crossbar Skip Enable Bits. These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar. 0: Corresponding P1.n pin is not skipped by the Crossbar. 1: Corresponding P1.n pin is skipped by the Crossbar. 133 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 13.13. P0SKIP: Port0 Skip R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xD4 Bits7–0: P1SKIP[7:0]: Port1 Crossbar Skip Enable Bits. These bits select Port pins to be skipped by the Crossbar Decoder. Port pins used as analog inputs (for ADC or Comparator) or used as special functions (VREF input, external oscillator circuit, CNVSTR input) should be skipped by the Crossbar. 0: Corresponding P1.n pin is not skipped by the Crossbar. 1: Corresponding P1.n pin is skipped by the Crossbar. SFR Definition 13.14. P1MAT: Port1 Match R/W R/W R/W R/W R/W R/W R/W R/W Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Reset Value 11111111 SFR Address: 0xCF Bits7–0: P1MAT[7:0]: Port1 Match Value. These bits control the value that unmasked P0 Port pins are compared against. A Port Match event is generated if (P1 & P1MASK) does not equal (P1MAT & P1MASK). SFR Definition 13.15. P1MASK: Port1 Mask R/W R/W R/W R/W R/W R/W R/W R/W Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Reset Value 00000000 SFR Address: 0xBF Bits7–0: P1MASK[7:0]: Port1 Mask Value. These bits select which Port pins will be compared to the value stored in P1MAT. 0: Corresponding P1.n pin is ignored and cannot cause a Port Match event. 1: Corresponding P1.n pin is compared to the corresponding bit in P1MAT. Rev. 1.4 134 C8051F52x/F52xA/F53x/F53xA 14. Oscillators C8051F52x/F52xA/F53x/F53xA devices include a programmable internal oscillator, an external oscillator drive circuit. The internal oscillator can be enabled/disabled and calibrated using the OSCICN and OSCICL registers, as shown in Figure 14.1. The system clock (SYSCLK) can be derived from the internal oscillator, external oscillator circuit. Oscillator electrical specifications are given in Table 2.11 on page 34. Option 3 XTAL2 CLKSEL CLKSL OSCICN IFCN2 IFCN1 IFCN0 OSCIFIN IOSCEN1 IOSCEN0 SUSPEND IFRDY OSCICL Option 2 VDD XTAL2 EN Programmable Internal Clock Generator Option 1 IOSC n SYSCLK XTAL1 EXOSC Input Circuit 10MΩ OSC Option 4 XTLVLD XTAL2 XFCN2 XFCN1 XFCN0 XTLVLD XOSCMD2 XOSCMD1 XOSCMD0 XTAL2 OSCXCN Figure 14.1. Oscillator Diagram 14.1. Programmable Internal Oscillator All C8051F52x/53x devices include a programmable internal oscillator that defaults as the system clock after a system reset. The internal oscillator period can be programmed via the OSCICL and OSCIFIN registers, shown in SFR Definition 14.2 and SFR Definition 14.3. On C8051F52x/53x devices, OSCICL and OSCIFIN are factory calibrated to obtain a 24.5 MHz frequency. Electrical specifications for the precision internal oscillator are given in Table 2.11 on page 34. Note that the system clock may be derived from the programmed internal oscillator divided by 1, 2, 4, 8, 16, 32, 64, or 128 as defined by the IFCN bits in register OSCICN. The divide value defaults to 128 following a reset. Rev. 1.4 135 C8051F52x/F52xA/F53x/F53xA 14.1.1. Internal Oscillator Suspend Mode When software writes a logic 1 to SUSPEND (OSCICN.5), the internal oscillator is suspended. If the system clock is derived from the internal oscillator, the input clock to the peripheral or CIP-51 will be stopped until one of the following events occur:  Port 0 Match Event. Port 1 Match Event.  Comparator 0 enabled and output is logic 0.  When one of the internal oscillator awakening events occur, the internal oscillator, CIP-51, and affected peripherals resume normal operation, regardless of whether the event also causes an interrupt. The CPU resumes execution at the instruction following the write to SUSPEND. Note: Please refer to Section “20.7. Internal Oscillator Suspend Mode” on page 212 for a note about suspend mode in older silicon revisions. 136 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 14.1. OSCICN: Internal Oscillator Control R/W R/W R/W IOSCEN1 IOSCEN0 SUSPEND Bit7 Bit6 Bit5 R R R/W R/W R/W Reset Value IFRDY — IFCN2 IFCN1 IFCN0 11000000 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xB2 Bits7–6: IOSCEN[1:0]: Internal Oscillator Enable Bits. 00: Oscillator Disabled. 01: Reserved. 10: Reserved. 11: Oscillator Enabled in Normal Mode and Disabled in Suspend Mode. Bit5: SUSPEND: Internal Oscillator Suspend Enable Bit. Setting this bit to logic 1 places the internal oscillator in SUSPEND mode. The internal oscillator resumes operation when one of the SUSPEND mode awakening events occur. Bit4: IFRDY: Internal Oscillator Frequency Ready Flag. 0: Internal Oscillator is not running at programmed frequency. 1: Internal Oscillator is running at programmed frequency. Bit3: UNUSED. Read = 0b, Write = don't care. Bits2–0: IFCN2–0: Internal Oscillator Frequency Control Bits. 000: SYSCLK derived from Internal Oscillator divided by 128 (default). 001: SYSCLK derived from Internal Oscillator divided by 64. 010: SYSCLK derived from Internal Oscillator divided by 32. 011: SYSCLK derived from Internal Oscillator divided by 16. 100: SYSCLK derived from Internal Oscillator divided by 8. 101: SYSCLK derived from Internal Oscillator divided by 4. 110: SYSCLK derived from Internal Oscillator divided by 2. 111: SYSCLK derived from Internal Oscillator divided by 1. Rev. 1.4 137 C8051F52x/F52xA/F53x/F53xA SFR Definition 14.2. OSCICL: Internal Oscillator Calibration R R/W R/W R/W — Bit7 R/W R/W R/W R/W Bit2 Bit1 Bit0 Reset Value OSCICL Bit6 Bit5 Bit4 Varies Bit3 SFR Address: 0xB3 Bit7: UNUSED. Read = 0b. Write = don’t care. Bits6–0: OSCICL: Internal Oscillator Calibration Register. This register determines the internal oscillator period. On C8051F52x/53x devices, the reset value is factory calibrated to generate an internal oscillator frequency of 24.5 MHz. SFR Definition 14.3. OSCIFIN: Internal Fine Oscillator Calibration R/W R/W — — Bit7 Bit6 R/W R R R/W R/W R/W OSCIFIN Bit5 Bit4 Bit3 Bit2 Reset Value undetermined Bit1 Bit0 Bit Addressable SFR Address: 0xB0 Bits7–6: UNUSED. Read = 00b, Write = don't care. Bits5–0: OSCIFIN. Internal oscillator fine adjustment bits. The valid range is between 0x00 and 0x27. This register is a fine adjustment for the internal oscillator period. On C8051F52x/52xA/53x/53xA devices, the reset value is factory calibrated to generate an internal oscillator frequency of 24.5 MHz. 138 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 14.2. External Oscillator Drive Circuit The external oscillator circuit may drive an external crystal, ceramic resonator, capacitor, or RC network. A CMOS clock may also provide a clock input. For a crystal or ceramic resonator configuration, the crystal/resonator must be wired across the XTAL1 and XTAL2 pins as shown in Option 1 of Figure 14.1. A 10 MΩ resistor also must be wired across the XTAL1 and XTAL2 pins for the crystal/resonator configuration. In RC, capacitor, or CMOS clock configuration, the clock source should be wired to the XTAL2 pin as shown in Option 2, 3, or 4 of Figure 14.1. The type of external oscillator must be selected in the OSCXCN register, and the frequency control bits (XFCN) must be selected appropriately (see SFR Definition 14.4. OSCXCN: External Oscillator Control). Important Note on External Oscillator Usage: Port pins must be configured when using the external oscillator circuit. When the external oscillator drive circuit is enabled in crystal/resonator mode, Port pins P0.7 and P1.0 ('F53x/'F53xA) or P0.2 and P0.3 ('F52x/'F52xA) are used as XTAL1 and XTAL2 respectively. When the external oscillator drive circuit is enabled in capacitor, RC, or CMOS clock mode, Port pin P1.0 ('F53x/'F53xA) or P0.3 ('F52x/'F52xA) is used as XTAL2. The Port I/O Crossbar should be configured to skip the Port pins used by the oscillator circuit; see Section “13.1. Priority Crossbar Decoder” on page 122 for Crossbar configuration. Additionally, when using the external oscillator circuit in crystal/resonator, capacitor, or RC mode, the associated Port pins should be configured as analog inputs. In CMOS clock mode, the associated pin should be configured as a digital input. See Section “13.2. Port I/O Initialization” on page 126 for details on Port input mode selection. 14.2.1. Clocking Timers Directly Through the External Oscillator The external oscillator source divided by eight is a clock option for the timers (Section “18. Timers” on page 182) and the Programmable Counter Array (PCA) (Section “19. Programmable Counter Array (PCA0)” on page 195). When the external oscillator is used to clock these peripherals, but is not used as the system clock, the external oscillator frequency must be less than or equal to the system clock frequency. In this configuration, the clock supplied to the peripheral (external oscillator / 8) is synchronized with the system clock; the jitter associated with this synchronization is limited to ±0.5 system clock cycles. 14.2.2. External Crystal Example If a crystal or ceramic resonator is used as an external oscillator source for the MCU, the circuit should be configured as shown in Figure 14.1, Option 1. The External Oscillator Frequency Control value (XFCN) should be chosen from the Crystal column of the table in SFR Definition 14.4. For example, a 12 MHz crystal requires an XFCN setting of 111b. When the crystal oscillator is first enabled, the oscillator amplitude detection circuit requires a settling time to achieve proper bias. Introducing a delay of 1 ms between enabling the oscillator and checking the XTLVLD bit will prevent a premature switch to the external oscillator as the system clock. Switching to the external oscillator before the crystal oscillator has stabilized can result in unpredictable behavior. The recommended procedure is: 1. Configure XTAL1 and XTAL2 pins by writing 1 to the port latch. 2. Configure XTAL1 and XTAL2 as analog inputs. 3. Enable the external oscillator. 4. Wait at least 1 ms. 5. Poll for XTLVLD => 1. 6. Switch the system clock to the external oscillator. Note: Tuning-fork crystals may require additional settling time before XTLVLD returns a valid result. The capacitors shown in the external crystal configuration provide the load capacitance required by the crystal for correct oscillation. These capacitors are "in series" as seen by the crystal and "in parallel" with the stray capacitance of the XTAL1 and XTAL2 pins. Rev. 1.4 139 C8051F52x/F52xA/F53x/F53xA Note: The load capacitance depends upon the crystal and the manufacturer. Please refer to the crystal data sheet when completing these calculations. The equation for determining the load capacitance for two capacitors is: CA × CB C L = -------------------- + C S CA + CB Where: CA and CB are the capacitors connected to the crystal leads. CS is the total stray capacitance of the PCB. The stray capacitance for a typical layout where the crystal is as close as possible to the pins is 2–5 pF per pin. If CA and CB are the same (C), then the equation becomes: C C L = ---- + C S 2 For example, a tuning-fork crystal of 32 kHz with a recommended load capacitance of 12.5 pF should use the configuration shown in Figure 14.1, Option 1. With a stray capacitance of 3 pF per pin (6 pF total), the 13 pF capacitors yield an equivalent capacitance of 12.5 pF across the crystal, as shown in Figure 14.2. 13 pF XTAL1 Ω 10 MΩ 32 kHz XTAL2 13 pF Figure 14.2. 32 kHz External Crystal Example Important Note on External Crystals: Crystal oscillator circuits are quite sensitive to PCB layout. The crystal should be placed as close as possible to the XTAL pins on the device. The traces should be as short as possible and shielded with ground plane from any other traces which could introduce noise or interference. 140 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 14.2.3. External RC Example If an RC network is used as an external oscillator source for the MCU, the circuit should be configured as shown in Figure 14.1, Option 2. The capacitor should be no greater than 100 pF; however for very small capacitors, the total capacitance may be dominated by parasitic capacitance in the PCB layout. To determine the required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, first select the RC network value to produce the desired frequency of oscillation. If the frequency desired is 100 kHz, let R = 246 kΩ and C = 50 pF: f = 1.23( 103 ) / RC = 1.23 ( 103 ) / [ 246 x 50 ] = 0.1 MHz = 100 kHz Referring to the table in SFR Definition 14.4, the required XFCN setting is 010b. Programming XFCN to a higher setting in RC mode will improve frequency accuracy at a slightly increased external oscillator supply current. 14.2.4. External Capacitor Example If a capacitor is used as an external oscillator for the MCU, the circuit should be configured as shown in Figure 14.1, Option 3. The capacitor should be no greater than 100 pF; however for very small capacitors, the total capacitance may be dominated by parasitic capacitance in the PCB layout. To determine the required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, select the frequency of oscillation and calculate the capacitance to be used from the equations below. Assume VDD = 2.1 V and f = 75 kHz: f = KF / (C x VDD) 0.075 MHz = KF / (C x 2.1) Since the frequency of roughly 75 kHz is desired, select the K Factor from the table in SFR Definition 14.4 as KF = 7.7: 0.075 MHz = 7.7 / (C x 2.1) C x 2.1 = 7.7 / 0.075 MHz C = 102.6 / 2.0 pF = 51.3 pF Therefore, the XFCN value to use in this example is 010b. Rev. 1.4 141 C8051F52x/F52xA/F53x/F53xA SFR Definition 14.4. OSCXCN: External Oscillator Control R R/W R/W R/W R/W XTLVLD XOSCMD2 XOSCMD1 XOSCMD0 Reserved Bit7 Bit6 Bit5 Bit4 Bit3 R/W R/W R/W Reset Value XFCN2 XFCN1 XFCN0 00000000 Bit2 Bit1 Bit0 SFR Address: 0xB1 Bit7: XTLVLD: Crystal Oscillator Valid Flag. (Read only when XOSCMD = 11x.) 0: Crystal Oscillator is unused or not yet stable. 1: Crystal Oscillator is running and stable. Bits6–4: XOSCMD2–0: External Oscillator Mode Bits. 00x: External Oscillator circuit off. 010: External CMOS Clock Mode. 011: External CMOS Clock Mode with divide by 2 stage. 100: RC Oscillator Mode. 101: Capacitor Oscillator Mode. 110: Crystal Oscillator Mode. 111: Crystal Oscillator Mode with divide by 2 stage. Bit3: RESERVED. Read = 0b; Must write 0b. Bits2–0: XFCN2–0: External Oscillator Frequency Control Bits. 000-111: See table below: XFCN Crystal (XOSCMD = 11x) RC (XOSCMD = 10x) C (XOSCMD = 10x) 000 f ≤ 20 kHz f ≤ 25 kHz K Factor = 0.87 001 20 kHz < f ≤ 58 kHz 25 kHz < f ≤ 50 kHz K Factor = 2.6 010 58 kHz < f ≤ 155 kHz 50 kHz < f ≤ 100 kHz K Factor = 7.7 011 155 kHz < f ≤ 415 kHz 100 kHz < f ≤ 200 kHz K Factor = 22 100 415 kHz < f ≤ 1.1 MHz 200 kHz < f ≤ 400 kHz K Factor = 65 101 1.1 MHz < f ≤ 3.1 MHz 400 kHz < f ≤ 800 kHz K Factor = 180 110 3.1 MHz < f ≤ 8.2 MHz 800 kHz < f ≤ 1.6 MHz K Factor = 664 111 8.2 MHz < f ≤ 25 MHz 1.6 MHz < f ≤ 3.2 MHz K Factor = 1590 Crystal Mode (Circuit from Figure 14.1, Option 1; XOSCMD = 11x) Choose XFCN value to match crystal or resonator frequency. RC Mode (Circuit from Figure 14.1, Option 2; XOSCMD = 10x) Choose XFCN value to match frequency range: f = 1.23(103) / (R x C), where f = frequency of clock in MHz C = capacitor value in pF R = Pullup resistor value in kΩ C Mode (Circuit from Figure 14.1, Option 3; XOSCMD = 10x) Choose K Factor (KF) for the oscillation frequency desired: f = KF / (C x VDD), where f = frequency of clock in MHz C = capacitor value the XTAL2 pin in pF VDD = Power Supply on MCU in volts 142 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 14.3. System Clock Selection The internal oscillator requires little start-up time and may be selected as the system clock immediately following the OSCICN write that enables the internal oscillator. External crystals and ceramic resonators typically require a start-up time before they are settled and ready for use. The Crystal Valid Flag (XTLVLD in register OSCXCN) is set to 1 by hardware when the external oscillator is settled. To avoid reading a false XTLVLD in crystal mode, the software should delay at least 1 ms between enabling the external oscillator and checking XTLVLD. RC and C modes typically require no startup time. The CLKSL bit in register CLKSEL selects which oscillator source is used as the system clock. CLKSL must be set to 1 for the system clock to run from the external oscillator; however the external oscillator may still clock certain peripherals (timers, PCA) when another oscillator is selected as the system clock. The system clock may be switched on-the-fly between the internal oscillator and external oscillator, as long as the selected clock source is enabled and has settled. SFR Definition 14.5. CLKSEL: Clock Select R R - - Bit7 Bit6 R/W R/W Reserved Reserved Bit5 Bit4 R - R/W R/W Reserved Reserved Bit3 Bit2 Bit1 R/W Reset Value CLKSL 00000000 Bit0 SFR Address: Bits7–6: Bits5–4: Bit3: Bits2–1: Bit0: 0xA9 Unused. Read = 00b; Write = don’t care. Reserved. Read = 00b; Must write 00b. Unused. Read = 0b; Write = don’t care. Reserved. Read = 00b; Must write 00b. CLKSL: System Clock Select 0: Internal Oscillator (as determined by the IFCN bits in register OSCICN). 1: External Oscillator. Rev. 1.4 143 C8051F52x/F52xA/F53x/F53xA 15. UART0 UART0 is an asynchronous, full duplex serial port offering modes 1 and 3 of the standard 8051 UART. Enhanced baud rate support allows a wide range of clock sources to generate standard baud rates (details in Section “15.1. Enhanced Baud Rate Generation” on page 145). Received data buffering allows UART0 to start reception of a second incoming data byte before software has finished reading the previous data byte. (Please refer to Section “20. Device Specific Behavior” on page 210 for more information on the pins associated with the UART interface.) UART0 has two associated SFRs: Serial Control Register 0 (SCON0) and Serial Data Buffer 0 (SBUF0). The single SBUF0 location provides access to both transmit and receive registers. Writes to SBUF0 always access the Transmit register. Reads of SBUF0 always access the buffered Receive register; it is not possible to read data from the Transmit register. With UART0 interrupts enabled, an interrupt is generated each time a transmit is completed (TI0 is set in SCON0), or a data byte has been received (RI0 is set in SCON0). The UART0 interrupt flags are not cleared by hardware when the CPU vectors to the interrupt service routine. They must be cleared manually by software, allowing software to determine the cause of the UART0 interrupt (transmit complete or receive complete). SFR Bus Write to SBUF TB8 SBUF (TX Shift) SET D Q TX CLR Crossbar Zero Detector Stop Bit Shift Start Data Tx Control Tx Clock Send Tx IRQ SCON TI Serial Port Interrupt MCE REN TB8 RB8 TI RI SMODE UART Baud Rate Generator Port I/O RI Rx IRQ Rx Clock Rx Control Start Shift 0x1FF Load SBUF RB8 Input Shift Register (9 bits) Load SBUF SBUF (RX Latch) Read SBUF SFR Bus RX Crossbar Figure 15.1. UART0 Block Diagram Rev. 1.4 144 C8051F52x/F52xA/F53x/F53xA 15.1. Enhanced Baud Rate Generation The UART0 baud rate is generated by Timer 1 in 8-bit auto-reload mode. The TX clock is generated by TL1; the RX clock is generated by a copy of TL1 (shown as RX Timer in Figure 15.2), which is not useraccessible. Both TX and RX Timer overflows are divided by two to generate the TX and RX baud rates. The RX Timer runs when Timer 1 is enabled, and uses the same reload value (TH1). However, an RX Timer reload is forced when a START condition is detected on the RX pin. This allows a receive to begin any time a START is detected, independent of the TX Timer state. Timer 1 TL1 UART Overflow 2 TX Clock Overflow 2 RX Clock TH1 Start Detected RX Timer Figure 15.2. UART0 Baud Rate Logic Timer 1 should be configured for Mode 2, 8-bit auto-reload (see Section “18.1.3. Mode 2: 8-bit Counter/Timer with Auto-Reload” on page 184). The Timer 1 reload value should be set so that overflows will occur at two times the desired UART baud rate frequency. Note that Timer 1 may be clocked by one of six sources: SYSCLK, SYSCLK / 4, SYSCLK / 12, SYSCLK / 48, the external oscillator clock / 8, or an external input T1. The UART0 baud rate is determined by Equation 15.1-A and Equation 15.1-B. A) B) 1 UartBaudRate = --- x T1_Overflow_Rate 2 T1 CLK T1_Overflow_Rate = -------------------------256 – TH1 Equation 15.1. UART0 Baud Rate Where T1CLK is the frequency of the clock supplied to Timer 1, and T1H is the high byte of Timer 1 (8-bit auto-reload mode reload value). Timer 1 clock frequency is selected as described in Section “18. Timers” on page 182. A quick reference for typical baud rates and system clock frequencies is given in Table 15.1. Note that the internal oscillator may still generate the system clock when the external oscillator is driving Timer 1. 145 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 15.2. Operational Modes UART0 provides standard asynchronous, full duplex communication. The UART mode (8-bit or 9-bit) is selected by the S0MODE bit (SCON0.7). Typical UART connection options are shown below. TX RS-232 LEVEL XLTR RS-232 RX C8051Fxxx OR TX TX RX RX MCU C8051Fxxx Figure 15.3. UART Interconnect Diagram 15.2.1. 8-Bit UART 8-Bit UART mode uses a total of 10 bits per data byte: one start bit, eight data bits (LSB first), and one stop bit. Data are transmitted LSB first from the TX0 pin and received at the RX0 pin. On receive, the eight data bits are stored in SBUF0 and the stop bit goes into RB80 (SCON0.2). Data transmission begins when software writes a data byte to the SBUF0 register. The TI0 Transmit Interrupt Flag (SCON0.1) is set at the end of the transmission (the beginning of the stop-bit time). Data reception can begin any time after the REN0 Receive Enable bit (SCON0.4) is set to logic 1. After the stop bit is received, the data byte will be loaded into the SBUF0 receive register if the following conditions are met: RI0 must be logic 0, and if MCE0 is logic 1, the stop bit must be logic 1. In the event of a receive data overrun, the first received 8 bits are latched into the SBUF0 receive register and the following overrun data bits are lost. If these conditions are met, the eight bits of data is stored in SBUF0, the stop bit is stored in RB80 and the RI0 flag is set. If these conditions are not met, SBUF0 and RB80 will not be loaded and the RI0 flag will not be set. An interrupt will occur if enabled when either TI0 or RI0 is set. MARK SPACE START BIT D0 D1 D2 D3 D4 D5 D6 D7 STOP BIT BIT TIMES BIT SAMPLING Figure 15.4. 8-Bit UART Timing Diagram Rev. 1.4 146 C8051F52x/F52xA/F53x/F53xA 15.2.2. 9-Bit UART 9-bit UART mode uses a total of eleven bits per data byte: a start bit, 8 data bits (LSB first), a programmable ninth data bit, and a stop bit. The state of the ninth transmit data bit is determined by the value in TB80 (SCON0.3), which is assigned by user software. It can be assigned the value of the parity flag (bit P in register PSW) for error detection, or used in multiprocessor communications. On receive, the ninth data bit goes into RB80 (SCON0.2) and the stop bit is ignored. Data transmission begins when an instruction writes a data byte to the SBUF0 register. The TI0 Transmit Interrupt Flag (SCON0.1) is set at the end of the transmission (the beginning of the stop-bit time). Data reception can begin any time after the REN0 Receive Enable bit (SCON0.4) is set to 1. After the stop bit is received, the data byte will be loaded into the SBUF0 receive register if the following conditions are met: (1) RI0 must be logic 0, and (2) if MCE0 is logic 1, the 9th bit must be logic 1 (when MCE0 is logic 0, the state of the ninth data bit is unimportant). If these conditions are met, the eight bits of data are stored in SBUF0, the ninth bit is stored in RB80, and the RI0 flag is set to 1. If the above conditions are not met, SBUF0 and RB80 will not be loaded and the RI0 flag will not be set to 1. A UART0 interrupt will occur if enabled when either TI0 or RI0 is set to 1. MARK SPACE START BIT D0 D1 D2 D3 D4 D5 D6 BIT TIMES BIT SAMPLING Figure 15.5. 9-Bit UART Timing Diagram 147 Rev. 1.4 D7 D8 STOP BIT C8051F52x/F52xA/F53x/F53xA 15.3. Multiprocessor Communications 9-Bit UART mode supports multiprocessor communication between a master processor and one or more slave processors by special use of the ninth data bit. When a master processor wants to transmit to one or more slaves, it first sends an address byte to select the target(s). An address byte differs from a data byte in that its ninth bit is logic 1; in a data byte, the ninth bit is always set to logic 0. Setting the MCE0 bit (SCON0.5) of a slave processor configures its UART such that when a stop bit is received, the UART will generate an interrupt only if the ninth bit is logic 1 (RB80 = 1) signifying an address byte has been received. In the UART interrupt handler, software will compare the received address with the slave's own assigned 8-bit address. If the addresses match, the slave will clear its MCE0 bit to enable interrupts on the reception of the following data byte(s). Slaves that weren't addressed leave their MCE0 bits set and do not generate interrupts on the reception of the following data bytes, thereby ignoring the data. Once the entire message is received, the addressed slave resets its MCE0 bit to ignore all transmissions until it receives the next address byte. Multiple addresses can be assigned to a single slave and/or a single address can be assigned to multiple slaves, thereby enabling "broadcast" transmissions to more than one slave simultaneously. The master processor can be configured to receive all transmissions or a protocol can be implemented such that the master/slave role is temporarily reversed to enable half-duplex transmission between the original master and slave(s). Master Device Slave Device Slave Device Slave Device V+ RX TX RX TX RX TX RX TX Figure 15.6. UART Multi-Processor Mode Interconnect Diagram Rev. 1.4 148 C8051F52x/F52xA/F53x/F53xA SFR Definition 15.1. SCON0: Serial Port 0 Control R/W R R/W R/W R/W R/W R/W R/W Reset Value S0MODE - MCE0 REN0 TB80 RB80 TI0 RI0 01000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Bit Addressable SFR Address: 0x98 Bit7: Bit6: Bit5: Bit4: Bit3: Bit2: Bit1: Bit0: 149 S0MODE: Serial Port 0 Operation Mode. This bit selects the UART0 Operation Mode. 0: 8-bit UART with Variable Baud Rate. 1: 9-bit UART with Variable Baud Rate. UNUSED. Read = 1b. Write = don’t care. MCE0: Multiprocessor Communication Enable. The function of this bit is dependent on the Serial Port 0 Operation Mode. S0MODE = 0: Checks for valid stop bit. 0: Logic level of stop bit is ignored. 1: RI0 will only be activated if stop bit is logic level 1. S0MODE = 1: Multiprocessor Communications Enable. 0: Logic level of ninth bit is ignored. 1: RI0 is set and an interrupt is generated only when the ninth bit is logic 1. REN0: Receive Enable. This bit enables/disables the UART receiver. 0: UART0 reception disabled. 1: UART0 reception enabled. TB80: Ninth Transmission Bit. The logic level of this bit will be assigned to the ninth transmission bit in 9-bit UART Mode. It is not used in 8-bit UART Mode. Set or cleared by software as required. RB80: Ninth Receive Bit. RB80 is assigned the value of the STOP bit in Mode 0; it is assigned the value of the 9th data bit in Mode 1. TI0: Transmit Interrupt Flag. Set by hardware when a byte of data has been transmitted by UART0 (after the 8th bit in 8bit UART Mode, or at the beginning of the STOP bit in 9-bit UART Mode). When the UART0 interrupt is enabled, setting this bit causes the CPU to vector to the UART0 interrupt service routine. This bit must be cleared manually by software. RI0: Receive Interrupt Flag. Set to 1 by hardware when a byte of data has been received by UART0 (set at the STOP bit sampling time). When the UART0 interrupt is enabled, setting this bit to 1 causes the CPU to vector to the UART0 interrupt service routine. This bit must be cleared manually by software. Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 15.2. SBUF0: Serial (UART0) Port Data Buffer R/W R/W R/W R/W R/W R/W R/W R/W Reset Value 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0x99 Bits7–0: SBUF0[7:0]: Serial Data Buffer Bits 7–0 (MSB–LSB) This SFR accesses two registers; a transmit shift register and a receive latch register. When data is written to SBUF0, it goes to the transmit shift register and is held for serial transmission. Writing a byte to SBUF0 initiates the transmission. A read of SBUF0 returns the contents of the receive latch. Table 15.1. Timer Settings for Standard Baud Rates Using the Internal Oscillator Frequency: 24.5 MHz SYSCLK from Internal Osc. Target Baud Rate (bps) 230400 115200 57600 28800 14400 9600 2400 1200 Baud Rate % Error Timer Clock SCA1–SCA0 Oscillator Source (pre-scale Divide select)* Factor T1M* –0.32% 106 SYSCLK XX 1 –0.32% 212 SYSCLK XX 1 0.15% 426 SYSCLK XX 1 –0.32% 848 SYSCLK / 4 01 0 0.15% 1704 SYSCLK / 12 00 0 –0.32% 2544 SYSCLK / 12 00 0 –0.32% 10176 SYSCLK / 48 10 0 0.15% 20448 SYSCLK / 48 10 0 X = Don’t care Note: SCA1–SCA0 and T1M bit definitions can be found in Section 18.1. Rev. 1.4 Timer 1 Reload Value (hex) 0xCB 0x96 0x2B 0x96 0xB9 0x96 0x96 0x2B 150 C8051F52x/F52xA/F53x/F53xA 16. Enhanced Serial Peripheral Interface (SPI0) The Serial Peripheral Interface (SPI0) provides access to a flexible, full-duplex synchronous serial bus. SPI0 can operate as a master or slave device in both 3-wire or 4-wire modes, and supports multiple masters and slaves on a single SPI bus. The slave-select (NSS) signal can be configured as an input to select SPI0 in slave mode, or to disable Master Mode operation in a multi-master environment, avoiding contention on the SPI bus when more than one master attempts simultaneous data transfers. NSS can also be configured as a chip-select output in master mode, or disabled for 3-wire operation. Additional general purpose port I/O pins can be used to select multiple slave devices in master mode. SFR Bus SYSCLK SPI0CN SPIBSY MSTEN CKPHA CKPOL SLVSEL NSSIN SRMT RXBMT SPIF WCOL MODF RXOVRN NSSMD1 NSSMD0 TXBMT SPIEN SPI0CFG SCR7 SCR6 SCR5 SCR4 SCR3 SCR2 SCR1 SCR0 SPI0CKR Clock Divide Logic SPI CONTROL LOGIC Data Path Control SPI IRQ Pin Interface Control MOSI Tx Data SPI0DAT SCK Transmit Data Buffer Shift Register 7 6 5 4 3 2 1 0 Rx Data Pin Control Logic Receive Data Buffer MISO C R O S S B A R Port I/O NSS Read SPI0DAT Write SPI0DAT SFR Bus Figure 16.1. SPI Block Diagram Rev. 1.4 151 C8051F52x/F52xA/F53x/F53xA 16.1. Signal Descriptions The four signals used by SPI0 (MOSI, MISO, SCK, NSS) are described below. 16.1.1. Master Out, Slave In (MOSI) The master-out, slave-in (MOSI) signal is an output from a master device and an input to slave devices. It is used to serially transfer data from the master to the slave. This signal is an output when SPI0 is operating as a master and an input when SPI0 is operating as a slave. Data is transferred most-significant bit first. When configured as a master, MOSI is driven by the MSB of the shift register in both 3- and 4-wire mode. 16.1.2. Master In, Slave Out (MISO) The master-in, slave-out (MISO) signal is an output from a slave device and an input to the master device. It is used to serially transfer data from the slave to the master. This signal is an input when SPI0 is operating as a master and an output when SPI0 is operating as a slave. Data is transferred most-significant bit first. The MISO pin is placed in a high-impedance state when the SPI module is disabled and when the SPI operates in 4-wire mode as a slave that is not selected. When acting as a slave in 3-wire mode, MISO is always driven by the MSB of the shift register. 16.1.3. Serial Clock (SCK) The serial clock (SCK) signal is an output from the master device and an input to slave devices. It is used to synchronize the transfer of data between the master and slave on the MOSI and MISO lines. SPI0 generates this signal when operating as a master. The SCK signal is ignored by a SPI slave when the slave is not selected (NSS = 1) in 4-wire slave mode. 16.1.4. Slave Select (NSS) The function of the slave-select (NSS) signal is dependent on the setting of the NSSMD1 and NSSMD0 bits in the SPI0CN register. There are three possible modes that can be selected with these bits: 1. NSSMD[1:0] = 00: 3-Wire Master or 3-Wire Slave Mode: SPI0 operates in 3-wire mode, and NSS is disabled. When operating as a slave device, SPI0 is always selected in 3-wire mode. Since no select signal is present, SPI0 must be the only slave on the bus in 3-wire mode. This is intended for point-topoint communication between a master and one slave. 2. NSSMD[1:0] = 01: 4-Wire Slave or Multi-Master Mode: SPI0 operates in 4-wire mode, and NSS is enabled as an input. When operating as a slave, NSS selects the SPI0 device. When operating as a master, a 1-to-0 transition of the NSS signal disables the master function of SPI0 so that multiple master devices can be used on the same SPI bus. 3. NSSMD[1:0] = 1x: 4-Wire Master Mode: SPI0 operates in 4-wire mode, and NSS is enabled as an output. The setting of NSSMD0 determines what logic level the NSS pin will output. This configuration should only be used when operating SPI0 as a master device. See Figure 16.2, Figure 16.3, and Figure 16.4 for typical connection diagrams of the various operational modes. Note that the setting of NSSMD bits affects the pinout of the device. When in 3-wire master or 3-wire slave mode, the NSS pin will not be mapped by the crossbar. In all other modes, the NSS signal will be mapped to a pin on the device. See Section “13. Port Input/Output” on page 120 for general purpose port I/O and crossbar information. 152 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA 16.2. SPI0 Master Mode Operation A SPI master device initiates all data transfers on a SPI bus. SPI0 is placed in master mode by setting the Master Enable flag (MSTEN, SPI0CN.6). Writing a byte of data to the SPI0 data register (SPI0DAT) when in master mode writes to the transmit buffer. If the SPI shift register is empty, the byte in the transmit buffer is moved to the shift register, and a data transfer begins. The SPI0 master immediately shifts out the data serially on the MOSI line while providing the serial clock on SCK. The SPIF (SPI0CN.7) flag is set to logic 1 at the end of the transfer. If interrupts are enabled, an interrupt request is generated when the SPIF flag is set. While the SPI0 master transfers data to a slave on the MOSI line, the addressed SPI slave device simultaneously transfers data to the SPI master on the MISO line in a full-duplex operation. Therefore, the SPIF flag serves as both a transmit-complete and receive-data-ready flag. The data byte received from the slave is transferred MSB-first into the master's shift register. When a byte is fully shifted into the register, it is moved to the receive buffer where it can be read by the processor by reading SPI0DAT. When configured as a master, SPI0 can operate in one of three different modes: multi-master mode, 3-wire single-master mode, and 4-wire single-master mode. The default, multi-master mode is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 1. In this mode, NSS is an input to the device, and is used to disable the master SPI0 when another master is accessing the bus. When NSS is pulled low in this mode, MSTEN (SPI0CN.6) and SPIEN (SPI0CN.0) are set to 0 to disable the SPI master device, and a Mode Fault is generated (MODF, SPI0CN.5 = 1). Mode Fault will generate an interrupt if enabled. SPI0 must be manually re-enabled in software under these circumstances. In multi-master systems, devices will typically default to being slave devices while they are not acting as the system master device. In multi-master mode, slave devices can be addressed individually (if needed) using general-purpose I/O pins. Figure 16.2 shows a connection diagram between two master devices in multiple-master mode. 3-wire single-master mode is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 0. In this mode, NSS is not used and is not mapped to an external port pin through the crossbar. Any slave devices that must be addressed in this mode should be selected using general-purpose I/O pins. Figure 16.3 shows a connection diagram between a master device in 3-wire master mode and a slave device. 4-wire single-master mode is active when NSSMD1 (SPI0CN.3) = 1. In this mode, NSS is configured as an output pin and can be used as a slave-select signal for a single SPI device. In this mode, the output value of NSS is controlled (in software) with the bit NSSMD0 (SPI0CN.2). Additional slave devices can be addressed using general-purpose I/O pins. Figure 16.4 shows a connection diagram for a master device in 4-wire master mode and two slave devices. Rev. 1.4 153 C8051F52x/F52xA/F53x/F53xA Master Device 1 NSS GPIO MISO MISO MOSI MOSI SCK SCK GPIO NSS Master Device 2 Figure 16.2. Multiple-Master Mode Connection Diagram Master Device MISO MISO MOSI MOSI SCK SCK Slave Device Figure 16.3. 3-Wire Single Master and Slave Mode Connection Diagram Master Device MISO MISO MOSI MOSI GPIO SCK SCK NSS NSS MISO MOSI Slave Device Slave Device SCK NSS Figure 16.4. 4-Wire Single Master and Slave Mode Connection Diagram 16.3. SPI0 Slave Mode Operation When SPI0 is enabled and not configured as a master, it will operate as a SPI slave. As a slave, bytes are shifted in through the MOSI pin and out through the MISO pin by a master device controlling the SCK signal. A bit counter in the SPI0 logic counts SCK edges. When 8 bits have been shifted into the shift register, the SPIF flag is set to logic 1, and the byte is copied into the receive buffer. Data is read from the receive buffer by reading SPI0DAT. A slave device cannot initiate transfers. Data to be transferred to the master device is pre-loaded into the shift register by writing to SPI0DAT. Writes to SPI0DAT are double-buffered, and are placed in the transmit buffer first. If the shift register is empty, the contents of the transmit buffer will immediately be transferred into the shift register. When the shift register already contains data, the SPI will load the shift register with the transmit buffer’s contents after the last SCK edge of the next (or current) SPI transfer. 154 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA The shift register contents are locked after the slave detects the first edge of SCK. Writes to SPI0DAT that occur after the first SCK edge will be held in the TX latch until the end of the current transfer. When configured as a slave, SPI0 can be configured for 4-wire or 3-wire operation. The default, 4-wire slave mode, is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 1. In 4-wire mode, the NSS signal is routed to a port pin and configured as a digital input. SPI0 is enabled when NSS is logic 0, and disabled when NSS is logic 1. The bit counter is reset on a falling edge of NSS. Note that the NSS signal must be driven low at least 2 system clocks before the first active edge of SCK for each byte transfer. Figure 16.4 shows a connection diagram between two slave devices in 4-wire slave mode and a master device. 3-wire slave mode is active when NSSMD1 (SPI0CN.3) = 0 and NSSMD0 (SPI0CN.2) = 0. NSS is not used in this mode, and is not mapped to an external port pin through the crossbar. Since there is not a way of uniquely addressing the device in 3-wire slave mode, SPI0 must be the only slave device present on the bus. It is important to note that in 3-wire slave mode there is no external means of resetting the bit counter that determines when a full byte has been received. The bit counter can only be reset by disabling and reenabling SPI0 with the SPIEN bit. Figure 16.3 shows a connection diagram between a slave device in 3wire slave mode and a master device. 16.4. SPI0 Interrupt Sources When SPI0 interrupts are enabled, the following four flags will generate an interrupt when they are set to logic 1: Note that all of the following interrupt bits must be cleared by software. 1. The SPI Interrupt Flag, SPIF (SPI0CN.7) is set to logic 1 at the end of each byte transfer. This flag can occur in all SPI0 modes. 2. The Write Collision Flag, WCOL (SPI0CN.6) is set to logic 1 if a write to SPI0DAT is attempted when the transmit buffer has not been emptied to the SPI shift register. When this occurs, the write to SPI0DAT will be ignored, and the transmit buffer will not be written.This flag can occur in all SPI0 modes. 3. The Mode Fault Flag MODF (SPI0CN.5) is set to logic 1 when SPI0 is configured as a master in multimaster mode and the NSS pin is pulled low. When a Mode Fault occurs, the MSTEN and SPIEN bits in SPI0CN are set to logic 0 to disable SPI0 and allow another master device to access the bus. 4. The Receive Overrun Flag RXOVRN (SPI0CN.4) is set to logic 1 when configured as a slave, and a transfer is completed while the receive buffer still holds an unread byte from a previous transfer. The new byte is not transferred to the receive buffer, allowing the previously received data byte to be read. The data byte which caused the overrun is lost. Rev. 1.4 155 C8051F52x/F52xA/F53x/F53xA 16.5. Serial Clock Timing Four combinations of serial clock phase and polarity can be selected using the clock control bits in the SPI0 Configuration Register (SPI0CFG). The CKPHA bit (SPI0CFG.5) selects one of two clock phases (edge used to latch the data). The CKPOL bit (SPI0CFG.4) selects between a rising edge or a falling edge. Both master and slave devices must be configured to use the same clock phase and polarity. SPI0 should be disabled (by clearing the SPIEN bit, SPI0CN.0) when changing the clock phase or polarity. The clock and data line relationships are shown in Figure 16.5. The SPI0 Clock Rate Register (SPI0CKR) as shown in SFR Definition 16.3 controls the master mode serial clock frequency. This register is ignored when operating in slave mode. When the SPI is configured as a master, the maximum data transfer rate (bits/sec) is one-half the system clock frequency or 12.5 MHz, whichever is slower. When the SPI is configured as a slave, the maximum data transfer rate (bits/sec) for full-duplex operation is 1/10 the system clock frequency, provided that the master issues SCK, NSS (in 4wire slave mode), and the serial input data synchronously with the slave’s system clock. If the master issues SCK, NSS, and the serial input data asynchronously, the maximum data transfer rate (bits/sec) must be less than 1/10 the system clock frequency. In the special case where the master only wants to transmit data to the slave and does not need to receive data from the slave (i.e. half-duplex operation), the SPI slave can receive data at a maximum data transfer rate (bits/sec) of 1/4 the system clock frequency. This is provided that the master issues SCK, NSS, and the serial input data synchronously with the slave’s system clock. SCK (CKPOL=0, CKPHA=0) SCK (CKPOL=0, CKPHA=1) SCK (CKPOL=1, CKPHA=0) SCK (CKPOL=1, CKPHA=1) MISO/MOSI MSB Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Figure 16.5. Data/Clock Timing Relationship 16.6. SPI Special Function Registers SPI0 is accessed and controlled through four special function registers in the system controller: SPI0CN Control Register, SPI0DAT Data Register, SPI0CFG Configuration Register, and SPI0CKR Clock Rate Register. The four special function registers related to the operation of the SPI0 Bus are described in the following figures. 156 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 16.1. SPI0CFG: SPI0 Configuration R R/W R/W R/W R R R R Reset Value SPIBSY MSTEN CKPHA CKPOL SLVSEL NSSIN SRMT RXBMT 00000111 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xA1 Bit 7: Bit 6: Bit 5: Bit 4: Bit 3: Bit 2: Bit 1: Bit 0: SPIBSY: SPI Busy (read only). This bit is set to logic 1 when a SPI transfer is in progress (Master or Slave Mode). MSTEN: Master Mode Enable. 0: Disable master mode. Operate in slave mode. 1: Enable master mode. Operate as a master. CKPHA: SPI0 Clock Phase. This bit controls the SPI0 clock phase. 0: Data centered on first edge of SCK period.* 1: Data centered on second edge of SCK period.* CKPOL: SPI0 Clock Polarity. This bit controls the SPI0 clock polarity. 0: SCK line low in idle state. 1: SCK line high in idle state. SLVSEL: Slave Selected Flag (read only). This bit is set to logic 1 whenever the NSS pin is low indicating SPI0 is the selected slave. It is cleared to logic 0 when NSS is high (slave not selected). This bit does not indicate the instantaneous value at the NSS pin, but rather a de-glitched version of the pin input. NSSIN: NSS Instantaneous Pin Input (read only). This bit mimics the instantaneous value that is present on the NSS port pin at the time that the register is read. This input is not de-glitched. SRMT: Shift Register Empty (Valid in Slave Mode, read only). This bit will be set to logic 1 when all data has been transferred in/out of the shift register, and there is no new information available to read from the transmit buffer or write to the receive buffer. It returns to logic 0 when a data byte is transferred to the shift register from the transmit buffer or by a transition on SCK. NOTE: SRMT = 1 when in Master Mode. RXBMT: Receive Buffer Empty (Valid in Slave Mode, read only). This bit will be set to logic 1 when the receive buffer has been read and contains no new information. If there is new information available in the receive buffer that has not been read, this bit will return to logic 0. NOTE: RXBMT = 1 when in Master Mode. Note: See Table 16.1 for timing parameters. Rev. 1.4 157 C8051F52x/F52xA/F53x/F53xA SFR Definition 16.2. SPI0CN: SPI0 Control R/W R/W R/W SPIF WCOL MODF Bit7 Bit6 Bit5 R/W R/W R/W RXOVRN NSSMD1 NSSMD0 Bit4 Bit3 Bit2 R R/W Reset Value TXBMT SPIEN 00000110 Bit1 Bit0 Bit Addressable SFR Address: 0xF8 Bit7: SPIF: SPI0 Interrupt Flag. This bit is set to logic 1 by hardware at the end of a data transfer. If interrupts are enabled, setting this bit causes the CPU to vector to the SPI0 interrupt service routine. This bit is not automatically cleared by hardware. It must be cleared by software. Bit6: WCOL: Write Collision Flag. This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) if a write to SPI0DAT is attempted when the transmit buffer has not been emptied to the SPI shift register. When this occurs, the write to SPI0DAT will be ignored, and the transmit buffer will not be written. This bit is not automatically cleared by hardware. It must be cleared by software. Bit5: MODF: Mode Fault Flag. This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) when a master mode collision is detected (NSS is low, MSTEN = 1, and NSSMD[1:0] = 01). This bit is not automatically cleared by hardware. It must be cleared by software. Bit4: RXOVRN: Receive Overrun Flag (Slave Mode only). This bit is set to logic 1 by hardware (and generates a SPI0 interrupt) when the receive buffer still holds unread data from a previous transfer and the last bit of the current transfer is shifted into the SPI0 shift register. This bit is not automatically cleared by hardware. It must be cleared by software. Bits3–2: NSSMD1–NSSMD0: Slave Select Mode. Selects between the following NSS operation modes: (See Section “16.2. SPI0 Master Mode Operation” on page 153 and Section “16.3. SPI0 Slave Mode Operation” on page 154). 00: 3-Wire Slave or 3-wire Master Mode. NSS signal is not routed to a port pin. 01: 4-Wire Slave or Multi-Master Mode (Default). NSS is always an input to the device. 1x: 4-Wire Single-Master Mode. NSS signal is mapped as an output from the device and will assume the value of NSSMD0. Bit1: TXBMT: Transmit Buffer Empty. This bit will be set to logic 0 when new data has been written to the transmit buffer. When data in the transmit buffer is transferred to the SPI shift register, this bit will be set to logic 1, indicating that it is safe to write a new byte to the transmit buffer. Bit0: SPIEN: SPI0 Enable. This bit enables/disables the SPI. 0: SPI disabled. 1: SPI enabled. 158 Rev. 1.4 C8051F52x/F52xA/F53x/F53xA SFR Definition 16.3. SPI0CKR: SPI0 Clock Rate R/W R/W R/W R/W R/W R/W R/W R/W Reset Value SCR7 SCR6 SCR5 SCR4 SCR3 SCR2 SCR1 SCR0 00000000 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 SFR Address: 0xA2 Bits7–0: SCR7–SCR0: SPI0 Clock Rate. These bits determine the frequency of the SCK output when the SPI0 module is configured for master mode operation. The SCK clock frequency is a divided version of the system clock, and is given in the following equation, where SYSCLK is the system clock frequency and SPI0CKR is the 8-bit value held in the SPI0CKR register. SYSCLK f SCK = ------------------------------------------------2 × ( SPI0CKR + 1 ) for 0