ATSAM3U2EA-AU

SAM3U Series Atmel | SMART ARM-based Flash MCU DATASHEET Description The Atmel ® | SMART SAM3U series is a member of a family of Flash microcontrollers based on the high performance 32-bit ARM® Cortex®-M3 RISC processor. It operates at a maximum speed of 96 MHz and features up to 256 Kbytes of Flash and up to 52 Kbytes of SRAM. The peripheral set includes a High Speed USB Device Port with embedded transceiver, a High Speed MCI for SDIO/SD/MMC, an External Bus Interface with NAND Flash controller, up to 4 USARTs, up to 2 TWIs, up to 5 SPIs, as well as 4 PWM timers, one 3-channel 16bit general-purpose timer, a low-power RTC, a 12-bit ADC and a 10-bit ADC. The SAM3U devices have three software-selectable low-power modes: Sleep, Wait, and Backup. In Sleep mode, the processor is stopped while all other functions can be kept running. In Wait mode, all clocks and functions are stopped but some peripherals can be configured to wake up the system based on predefined conditions. In Backup mode, only the RTC, RTT, and wake-up logic are running. The Real-time Event Managment allows peripherals to receive, react to and send events in Active and Sleep modes without processor intervention. The SAM3U architecture is specifically designed to sustain high speed data transfers. It includes a multi-layer bus matrix as well as multiple SRAM banks, PDC and DMA channels that enable it to run tasks in parallel and maximize data throughput. It can operate from 1.62V to 3.6V and comes in 100-pin and 144-pin LQFP and BGA packages. The SAM3U device is particularly well suited for USB applications: data loggers, PC peripherals and any high speed bridge (USB to SDIO, USB to SPI, USB to External Bus Interface). Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1. 2 Features  Core ̶ ARM Cortex-M3 revision 2.0 running at up to 96 MHz ̶ Memory Protection Unit (MPU) ̶ Thumb®-2 instruction set  Memories ̶ 64 to 256 Kbytes embedded Flash, 128-bit wide access, memory accelerator, dual bank ̶ 16 to 48 Kbytes embedded SRAM with dual banks ̶ 16 Kbytes ROM with embedded bootloader routines (UART, USB) and IAP routines ̶ Static Memory Controller (SMC): SRAM, NOR, NAND support. NAND Flash controller with 4 Kbytes RAM buffer and ECC  System ̶ Embedded voltage regulator for single supply operation ̶ POR, BOD and Watchdog for safe reset ̶ Quartz or resonator oscillators: 3 to 20 MHz main and optional low power 32.768 kHz for RTC or device clock ̶ High precision 8/12 MHz factory trimmed internal RC oscillator with 4 MHz Default Frequency for fast device startup ̶ Slow Clock Internal RC oscillator as permanent clock for device clock in low power mode ̶ One PLL for device clock and one dedicated PLL for USB 2.0 High Speed Device ̶ Up to 17 Peripheral DMA Controller (PDC) channels and 4-channel central DMA  Low Power Modes ̶ Sleep, Wait, and Backup modes, down to 1.65 µA in Backup mode with RTC, RTT, and GPBR  Peripherals ̶ USB 2.0 Device: 480 Mbps, 4-Kbyte FIFO, up to 7 bidirectional Endpoints, dedicated DMA ̶ Up to 4 USARTs (ISO7816, IrDA®, Flow Control, SPI, Manchester support) and one UART ̶ Up to 2 TWI (I2C compatible) ̶ 1 Serial Perpheral Interface (SPI) ̶ 1 Synchronous Serial Controller (SSC) (I2S) ̶ 1 High Speed Multimedia Card Interface (HSMCI) (SDIO/SD/MMC) ̶ 3-channel 16-bit Timer/Counter (TC) for capture, compare and PWM ̶ 4-channel 16-bit PWM (PWMC) ̶ 32-bit Real-time Timer (RTT) and Real-time Clock (RTC) with calendar and alarm features ̶ 8-channel 12-bit 1 msps ADC with differential input mode and programmable gain stage ̶ 8-channel 10-bit ADC  I/O ̶ Up to 96 I/O lines with external interrupt capability (edge or level sensitivity), debouncing, glitch filtering and ondie Series Resistor Termination ̶ Three 32-bit Parallel Input/Outputs (PIO)  Packages ̶ 100-lead LQFP – 14 × 14 mm, pitch 0.5 mm ̶ 100-ball TFBGA – 9 × 9 mm, pitch 0.8 mm ̶ 144-lead LQFP – 20 × 20 mm, pitch 0.5 mm ̶ 144-ball LFBGA – 10 × 10 mm, pitch 0.8 mm SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1.1 Configuration Summary The SAM3U series devices differ in memory sizes, package and features list. Table 1-1 summarizes the configurations of the six devices. Table 1-1. Configuration Summary Feature ATSAM3U4E ATSAM3U2E ATSAM3U1E ATSAM3U4C ATSAM3U2C ATSAM3U1C 2 x 128 Kbytes 128 Kbytes 64 Kbytes 2 x 128 Kbytes 128 Kbytes 64 Kbytes Dual plane Single plane Single plane Dual plane Single plane Single plane SRAM 52 Kbytes 36 Kbytes 20 Kbytes 52 Kbytes 36 Kbytes 20 Kbytes Package LQFP144 BGA144 LQFP144 BGA144 LQFP144 BGA144 LQFP100 BGA100 LQFP100 BGA100 LQFP100 BGA100 External Bus Interface 8 or 16 bits, 4 chip selects, 24-bit address 8 or 16 bits, 4 chip selects, 24-bit address 8 or 16 bits, 4 chip selects, 24-bit address 8 bits, 2 chip selects, 8-bit address 8 bits, 2 chip selects, 8-bit address 8 bits, 2 chip selects, 8-bit address Number of PIOs 96 96 96 57 57 57 SPI 5 5 5 4 4 4 TWI 2 2 2 1 1 1 Flash USART 4 4 4 3 3 3 ADC 12-bit 8 channels 8 channels 8 channels 4 channels 4 channels 4 channels ADC 10-bit 8 channels 8 channels 8 channels 4 channels 4 channels 4 channels FWUP, SHDN pins Yes Yes Yes FWUP FWUP FWUP HSMCI Data Size 8 bits 8 bits 8 bits 4 bits 4 bits 4 bits Note: 1. The SRAM size takes into account the 4 Kbyte RAM buffer of the NAND Flash Controller (NFC) which can be used by the core if not used by the NFC. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 3 Block Diagram TST PCK0 -PCK2 SLAVE OSC 3-20 M PMC SM BOD RC 32K FLASH 2x128 Kbytes 1x128 Kbytes 1x64 Kbytes 8 GPBR SHDN FWUP SUPC RTC VDDBU NRSTB ERASE NRST POR UT DO N VD DI VD S Flash Unique Identifier RTT PDC 8-channel 12-bit ADC 10-bit ADC RSTC PIOA DMA I/D OSC 32K XIN32 XOUT32 NAND Flash Controller & ECC MPU WDT VDDUTMI L SysTick Counter N V I C EBI Voltage Regulator USB Device HS Cortex-M3 Processor fmax 96 MHz RC Osc. 12/8/4 M VDDCORE SE In-Circuit Emulator PLLA UPLL XIN XOUT HS UTMI Transceiver JTAG & Serial Wire System Controller VD MASTER D VB U T D G MI FS D DP F D SD H M D SD H P SD M 144-pin SAM3U4/2/1E Block Diagram JT AG Figure 2-1. TD TDI TMO/T R TC S/S AC K/ WD ES SW IO W O CL K 2. NAND Flash SRAM (4 Kbytes) 5-layer AHB Bus Matrix SRAM0 32 Kbytes 16 Kbytes 8 Kbytes PDC TWI0 TWI1 SRAM1 16 Kbytes 16 Kbytes ROM 16 Kbytes Peripheral DMA Controller Peripheral Bridge NCS0 NCS1 NRD NWR0/NWE NWR1/NBS1 4-Channel DMA Static Memory Controller APB PDC PDC UART USART0 USART1 USART2 USART3 PDC TC0 SPI SSC HSMCI TK TF TD R D R F R DA K 0DA C 7 D A C K 2B V VD RE DA F D1 NA AD 2 12 A BT B0 D0 RG -A -A D T D1 7 TW WD 2B C 0- 7 K0 TW -T D W 1 C K U 1 R C U XD TS T X R 0-C D SCTSO TS R K0 -RT 3 D - S TXX0 SC 3 D -RDK3 0- X TX 3 D D3 C D 0 PW D RI0 SR M PW H D 0 0 T M -P R0 L0 W TC -P MH L WM 3 TI K0- L3 O T TI A0 CL O -T K2 N B0- IOA PC T 2 S0 IOB -N 2 PC SP S3 C M K O M SI IS O -A G -A D1 TR AD EF VR AD Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 NCS2 NANDOE, NANDWE PIOB SAM3U Series [DATASHEET] NWAIT A23 A21/ NANDALE A22/ NANDCLE NCS3 PWM PIOC 4 NANDRDY D0-D15 A0/NBS0 A1 A2-A20 TST PCK0 -PCK2 In-Circuit Emulator PLLA OSC 3-20 M SysTick Counter N V I C PMC SM BOD RC 32K FLASH 2x128 Kbytes 1x128 Kbytes 1x64 Kbytes 8 GPBR SHDN FWUP SUPC RTC VDDBU NRSTB ERASE NRST POR N DO DI VD VD S Flash Unique Identifier RTT PDC 4-channel 12-bit ADC 10-bit ADC RSTC NAND Flash SRAM (4 Kbytes) 5-layer AHB Bus Matrix SRAM0 32 Kbytes 16 Kbytes 8 Kbytes SRAM1 16 Kbytes 16 Kbytes ROM 16 Kbytes Peripheral DMA Controller Peripheral Bridge 4-Channel DMA Static Memory Controller APB PDC PDC PDC TWI UART USART0 USART1 USART2 NANDRDY D0-D7 A0 A1 A2-A7 NCS0 NCS1 NRD NWE NANDALE NANDCLE PDC PWM TC0 SPI SSC HSMCI NANDOE, NANDWE G TR AD VR EF -A D1 2B V VD RE -A DA F D1 N AD 2 A 12 A BT B0 D0 RG -A -A D D3 12 B3 TW TW D C 0 K0 U R X C U D TS T X R 0-C D SCTSO TS R K0 -RT 2 D - S TXX0 SC 2 D -RDK2 0- X TX 2 D D2 C D 0 PW D RI0 SR M PW H D 0 0- T M P R0 L0 W TC -P MH LK WM 3 TI 0- L3 O T TI A0 CL O -T K2 N B0- IOA PC T 2 S0 IOB -N 2 PC SP S3 C M K O M SI IS O TK TF TD R D R F DA RK 0DA C 3 D A C K PIOB AD PIOA DMA I/D OSC 32K XIN32 XOUT32 NAND Flash Controller & ECC MPU WDT VDDUTMI EBI Voltage Regulator USB Device HS Cortex-M3 Processor fmax 96 MHz RC Osc. 12/8/4 M VDDCORE HS UTMI Transceiver JTAG & Serial Wire System Controller UPLL XIN XOUT D VB U T D G MI FS D DP FS D DM H D SD H P SD M SLAVE VD MASTER UT 100-pin SAM3U4/2/1C Block Diagram TD I TD O TM / T S RA TC / S C E K/ WD SW SW IO O CL K JT AG SE L Figure 2-2. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 5 3. Signal Description Table 3-1 gives details on the signal names classified by peripheral. Table 3-1. Signal Description List Signal Name Function Type Active Voltage Level Reference Comments Power Supplies VDDIO Peripherals I/O Lines Power Supply Power 1.62V to 3.6V VDDIN Voltage Regulator Input Power 1.8V to 3.6V VDDOUT Voltage Regulator Output Power 1.8V VDDUTMI USB UTMI+ Interface Power Supply Power 3.0V to 3.6V GNDUTMII USB UTMI+ Interface Ground Ground VDDBU Backup I/O Lines Power Supply Power GNDBU Backup Ground Ground VDDPLL PLL A, UPLL and Osc 3–20 MHz Power Supply Power GNDPLL PLL A, UPLL and Osc 3–20 MHz Ground Ground VDDANA ADC Analog Power Supply Power GNDANA ADC Analog Ground Ground VDDCORE Core, Memories and Peripherals Chip Power Supply Power GND Ground Ground 1.62V to 3.6V 1.62 V to 1.95V 2.0V to 3.6V 1.62V to 1.95V Clocks, Oscillators and PLLs XIN Main Oscillator Input Input XOUT Main Oscillator Output XIN32 Slow Clock Oscillator Input XOUT32 Slow Clock Oscillator Output Output VBG Bias Voltage Reference Analog PCK0–PCK2 Programmable Clock Output Output VDDPLL Output Input VDDBU VDDIO Shutdown, Wakeup Logic Push/pull SHDN Shut-Down Control 0: The device is in backup mode Output VDDBU FWUP Force Wake-Up Input Input Low 1: The device is running (not in backup mode) Needs external pull-up Serial Wire/JTAG Debug Port (SWJ-DP) TCK/SWCLK Test Clock/Serial Wire Clock Input TDI Test Data In Input Test Data Out/Trace Asynchronous Data Out TMS/SWDIO Test Mode Select/Serial Wire Input/Output Input JTAGSEL JTAG Selection Input SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 No pull-up resistor VDDIO Output(4) TDO/TRACESWO 6 No pull-up resistor No pull-up resistor High VDDBU Internal permanent pull-down Table 3-1. Signal Name Signal Description List (Continued) Function Type Active Voltage Level Reference Comments Flash Memory ERASE Flash and NVM Configuration Bits Erase Command Input High VDDBU Internal permanent 15K pulldown I/O Low VDDIO Internal permanent pullup Low Reset/Test NRST Microcontroller Reset NRSTB Asynchronous Microcontroller Reset Input TST Test Select Input Internal permanent pullup VDDBU Internal permanent pulldown Universal Asynchronous Receiver Transceiver - UART URXD UART Receive Data Input UTXD UART Transmit Data Output PIO Controller - PIOA - PIOB - PIOC Schmitt Trigger (1) PA0–PA31 Parallel IO Controller A Reset State: I/O - PIO Input - Internal pullup enabled Schmitt Trigger (2) PB0–PB31 Parallel IO Controller B VDDIO I/O Reset State: - PIO Input - Internal pullup enabled Schmitt Trigger(3) PC0–PC31 Parallel IO Controller C Reset State: I/O - PIO Input - Internal pullup enabled External Bus Interface D0–D15 Data Bus A0–A23 Address Bus NWAIT External Wait Signal I/O Output Input Low Static Memory Controller - SMC NCS0–NCS3 Chip Select Lines Output Low NWR0–NWR1 Write Signal Output Low NRD Read Signal Output Low NWE Write Enable Output Low NBS0–NBS1 Byte Mask Signal Output Low SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 7 Table 3-1. Signal Description List (Continued) Signal Name Function Type Active Voltage Level Reference Comments NAND Flash Controller - NFC NANDOE NAND Flash Output Enable Output Low NANDWE NAND Flash Write Enable Output Low NANDRDY NAND Ready Input High Speed Multimedia Card Interface - HSMCI CK Multimedia Card Clock I/O CDA Multimedia Card Slot A Command I/O DA0–DA7 Multimedia Card Slot A Data I/O Universal Synchronous Asynchronous Receiver Transmitter - USARTx SCKx USARTx Serial Clock I/O TXDx USARTx Transmit Data I/O RXDx USARTx Receive Data Input RTSx USARTx Request To Send CTSx USARTx Clear To Send DTR0 USART0 Data Terminal Ready DSR0 USART0 Data Set Ready Input DCD0 USART0 Data Carrier Detect Input RI0 USART0 Ring Indicator Input Output Input I/O Synchronous Serial Controller - SSC TD SSC Transmit Data Output RD SSC Receive Data Input TK SSC Transmit Clock I/O RK SSC Receive Clock I/O TF SSC Transmit Frame Sync I/O RF SSC Receive Frame Sync I/O Timer/Counter - TC TCLKx TC Channel x External Clock Input Input TIOAx TC Channel x I/O Line A I/O TIOBx TC Channel x I/O Line B I/O Pulse Width Modulation Controller - PWMC PWMHx PWM Waveform Output High for channel x PWMLx PWM Waveform Output Low for channel x PWMFI0–2 PWM Fault Input 8 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Output Output Input Only output in complementary mode when dead time insertion is enabled Table 3-1. Signal Description List (Continued) Signal Name Function Type Active Voltage Level Reference Comments Serial Peripheral Interface - SPI MISO Master In Slave Out I/O MOSI Master Out Slave In I/O SPCK SPI Serial Clock I/O NPCS0 SPI Peripheral Chip Select 0 I/O Low NPCS1–NPCS3 SPI Peripheral Chip Select Output Low Two-Wire Interface - TWI TWDx TWIx Two-wire Serial Data I/O TWCKx TWIx Two-wire Serial Clock I/O 12-bit Analog-to-Digital Converter - ADC12B AD12Bx Analog Inputs Analog AD12BTRG ADC Trigger Input AD12BVREF ADC Reference Analog 10-bit Analog-to-Digital Converter - ADC ADx Analog Inputs Analog ADTRG ADC Trigger Input ADVREF ADC Reference Analog Fast Flash Programming Interface - FFPI PGMEN0–PGMEN2 Programming Enabling Input PGMM0–PGMM3 Programming Mode Input PGMD0–PGMD15 Programming Data I/O PGMRDY Programming Ready Output High PGMNVALID Data Direction Output Low PGMNOE Programming Read Input Low PGMCK Programming Clock Input PGMNCMD Programming Command Input VDDIO Low USB High Speed Device - UDPHS DFSDM USB Device Full Speed Data - Analog DFSDP USB Device Full Speed Data + Analog DHSDM USB Device High Speed Data - Analog VDDUTMI DHSDP Notes: 1. 2. 3. 4. USB Device High Speed Data + Analog PIOA: Schmitt Trigger on all except PA14 on 100 and 144-pin packages. PIOB: Schmitt Trigger on all except PB9 to PB16, PB25 to PB31 on 100 and 144-pin packages. PIOC: Schmitt Trigger on all except PC20 to PC27 on 144-pin package. TDO pin is set in input mode when the Cortex-M3 Core is not in debug mode. Thus an external pull-up (100 kΩ) must be added to avoid current consumption due to floating input. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 9 3.1 Design Considerations To facilitate schematic capture when using a SAM3U design, refer to the application note SAM3U Microcontroller Series Schematic Check List (Atmel literature No. 11006). This application note and additonal documenation are available on www.atmel.com. 10 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 4. Package and Pinout SAM3U4E / SAM3U2E / SAM3U1E devices are available in 144-lead LQFP and 144-ball LFBGA packages. SAM3U4C / SAM3U2C / SAM3U1C devices are available in 100-lead LQFP and 100-ball TFBGA packages. 4.1 Package and Pinout (SAM3U4E / SAM3U2E / SAM3U1E Devices) 4.1.1 144-lead LQFP Package Outline Figure 4-1. Orientation of the 144-lead LQFP Package 73 108 109 72 144 37 36 1 See Section 43.3 “144-lead LQFP Package” for mechanical drawings and specifications. 4.1.2 144-ball LFBGA Package Outline Figure 4-2. Orientation of the 144-ball LFBGA Package TOP VIEW 12 11 10 9 8 7 6 5 4 3 2 1 A B C D E F G H J K L M BALL A1 See Section 43.4 “144-ball LFBGA Package” for mechanical drawings and specifications. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 11 4.1.3 144-lead LQFP Pinout Table 4-1. 144-lead LQFP Pinout (SAM3U4E / SAM3U2E / SAM3U1E Devices) 1 TDI 37 DHSDP 73 VDDANA 109 PA0/PGMNCMD 2 VDDOUT 38 DHSDM 74 ADVREF 110 PC0 3 VDDIN 39 VBG 75 GNDANA 111 PA1/PGMRDY 4 TDO/TRACESWO 40 VDDUTMI 76 AD12BVREF 112 PC1 5 PB31 41 DFSDM 77 PA22/PGMD14 113 PA2/PGMNOE 6 PB30 42 DFSDP 78 PA30 114 PC2 7 TMS/SWDIO 43 GNDUTMI 79 PB3 115 PA3/PGMNVALID 8 PB29 44 VDDCORE 80 PB4 116 PC3 9 TCK/SWCLK 45 PA28 81 PC15 117 PA4/PGMM0 10 PB28 46 PA29 82 PC16 118 PC4 11 NRST 47 PC22 83 PC17 119 PA5/PGMM1 12 PB27 48 PA31 84 PC18 120 PC5 13 PB26 49 PC23 85 VDDIO 121 PA6/PGMM2 14 PB25 50 VDDCORE 86 VDDCORE 122 PC6 15 PB24 51 VDDIO 87 PA13/PGMD5 123 PA7/PGMM3 16 VDDCORE 52 GND 88 PA14/PGMD6 124 PC7 17 VDDIO 53 PB0 89 PC10 125 VDDCORE 18 GND 54 PC24 90 GND 126 GND 19 PB23 55 PB1 91 PA15/PGMD7 127 VDDIO 20 PB22 56 PC25 92 PC11 128 PA8/PGMD0 21 PB21 57 PB2 93 PA16/PGMD8 129 PC8 22 PC21 58 PC26 94 PC12 130 PA9/PGMD1 23 PB20 59 PB11 95 PA17/PGMD9 131 PC9 24 PB19 60 GND 96 PB16 132 PA10/PGMD2 25 PB18 61 PB12 97 PB15 133 PA11/PGMD3 26 PB17 62 PB13 98 PC13 134 PA12/PGMD4 27 VDDCORE 63 PC27 99 PA18/PGMD10 135 FWUP 28 PC14 64 PA27 100 PA19/PGMD11 136 SHDN 29 PB14 65 PB5 101 PA20/PGMD12 137 ERASE 30 PB10 66 PB6 102 PA21/PGMD13 138 TST 31 PB9 67 PB7 103 PA23/PGMD15 139 VDDBU 32 PC19 68 PB8 104 VDDIO 140 GNDBU 33 GNDPLL 69 PC28 105 PA24 141 NRSTB 34 VDDPLL 70 PC29 106 PA25 142 JTAGSEL 35 XOUT 71 PC30 107 PA26 143 XOUT32 36 XIN 72 PC31 108 PC20 144 XIN32 12 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 4.1.4 144-ball LFBGA Pinout Table 4-2. 144-ball LFBGA Pinout (SAM3U4E / SAM3U2E / SAM3U1E Devices) A1 VBG D1 DFSDM G1 PB0 K1 PB7 A2 VDDUTMI D2 DHSDM G2 PC26 K2 PC31 A3 PB9 D3 GNDPLL G3 PB2 K3 PC29 A4 PB10 D4 PC14 G4 PC25 K4 PB3 A5 PB19 D5 PB21 G5 PB1 K5 PB4 A6 PC21 D6 PB23 G6 GND K6 PA14/PGMD6 A7 PB26 D7 PB24 G7 GND K7 PA16/PGMD8 A8 TCK/SWCLK D8 PB28 G8 VDDCORE K8 PA18/PGMD10 A9 PB30 D9 TDI G9 PC4 K9 PC20 A10 TDO/TRACESWO D10 VDDBU G10 PA6/PGMM2 K10 PA1/PGMRDY A11 XIN32 D11 PA10/PGMD2 G11 PA7/PGMM3 K11 PC1 A12 XOUT32 D12 PA11/PGMD3 G12 PC6 K12 PC2 B1 VDDCORE E1 PC22 H1 PC24 L1 PC30 B2 GNDUTMI E2 PA28 H2 PC27 L2 ADVREF B3 XOUT E3 PC19 H3 PA27 L3 AD12BVREF B4 PB14 E4 VDDCORE H4 PB12 L4 PA22/PGMD14 B5 PB17 E5 GND H5 PB11 L5 PC17 B6 PB22 E6 VDDIO H6 GND L6 PC10 B7 PB25 E7 GNDBU H7 VDDCORE L7 PC12 B8 PB29 E8 NRST H8 PB16 L8 PA19/PGMD11 B9 VDDIN E9 PB31 H9 PB15 L9 PA23/PGMD15 B10 JTAGSEL E10 PA12/PGMD4 H10 PC3 L10 PA0/PGMNCMD B11 ERASE E11 PA8/PGMD0 H11 PA5/PGMM1 L11 PA26 B12 SHDN E12 PC8 H12 PC5 L12 PC0 C1 DFSDP F1 PA31 J1 PB5 M1 VDDANA C2 DHSDP F2 PA29 J2 PB6 M2 GNDANA C3 XIN F3 PC23 J3 PC28 M3 PA30 C4 VDDPLL F4 VDDCORE J4 PB8 M4 PC15 C5 PB18 F5 VDDIO J5 PB13 M5 PC16 C6 PB20 F6 GND J6 VDDIO M6 PC18 C7 PB27 F7 GND J7 PA13/PGMD5 M7 PA15/PGMD7 C8 TMS/SWDIO F8 VDDIO J8 PA17/PGMD9 M8 PC11 C9 VDDOUT F9 PC9 J9 PC13 M9 PA20/PGMD12 C10 NRSTB F10 PA9/PGMD1 J10 PA2/PGMNOE M10 PA21/PGMD13 C11 TST F11 VDDCORE J11 PA3/PGMNVALID M11 PA24 C12 FWUP F12 PC7 J12 PA4/PGMM0 M12 PA25 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 13 4.2 Package and Pinout (SAM3U4C / SAM3U2C / SAM3U1C Devices) 4.2.1 100-lead LQFP Package Outline Figure 4-3. Orientation of the 100-lead LQFP Package 75 51 76 50 100 26 1 25 See Section 43.1 “100-lead LQFP Package” for mechanical drawings and specifications. 4.2.2 100-ball TFBGA Package Outline Figure 4-4. Orientation of the 100-ball TFBGA Package TOP VIEW 1 2 3 4 5 6 7 8 9 10 A B C D E F G H J K See Section 43.2 “100-ball TFBGA Package” for mechanical drawings and specifications. 14 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 4.2.3 100-lead LQFP Pinout Table 4-3. 100-lead LQFP Pinout (SAM3U4C / SAM3U2C / SAM3U1C Devices) 1 VDDANA 26 PA0/PGMNCMD 51 TDI 76 DHSDP 2 ADVREF 27 PA1/PGMRDY 52 VDDOUT 77 DHSDM 3 GNDANA 28 PA2/PGMNOE 53 VDDIN 78 VBG 4 AD12BVREF 29 PA3/PGMNVALID 54 TDO/TRACESWO 79 VDDUTMI 5 PA22/PGMD14 30 PA4/PGMM0 55 TMS/SWDIO 80 DFSDM 6 PA30 31 PA5/PGMM1 56 TCK/SWCLK 81 DFSDP 7 PB3 32 PA6/PGMM2 57 NRST 82 GNDUTMI 8 PB4 33 PA7/PGMM3 58 PB24 83 VDDCORE 9 VDDCORE 34 VDDCORE 59 VDDCORE 84 PA28 10 PA13/PGMD5 35 GND 60 VDDIO 85 PA29 11 PA14/PGMD6 36 VDDIO 61 GND 86 PA31 12 PA15/PGMD7 37 PA8/PGMD0 62 PB23 87 VDDCORE 13 PA16/PGMD8 38 PA9/PGMD1 63 PB22 88 VDDIO 14 PA17/PGMD9 39 PA10/PGMD2 64 PB21 89 GND 15 PB16 40 PA11/PGMD3 65 PB20 90 PB0 16 PB15 41 PA12/PGMD4 66 PB19 91 PB1 17 PA18/PGMD10 42 FWUP 67 PB18 92 PB2 18 PA19/PGMD11 43 ERASE 68 PB17 93 PB11 19 PA20/PGMD12 44 TST 69 PB14 94 PB12 20 PA21/PGMD13 45 VDDBU 70 PB10 95 PB13 21 PA23/PGMD15 46 GNDBU 71 PB9 96 PA27 22 VDDIO 47 NRSTB 72 GNDPLL 97 PB5 23 PA24 48 JTAGSEL 73 VDDPLL 98 PB6 24 PA25 49 XOUT32 74 XOUT 99 PB7 25 PA26 50 XIN32 75 XIN 100 PB8 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 15 4.2.4 100-ball TFBGA Pinout Table 4-4. 100-ball TFBGA Pinout (SAM3U4C / SAM3U2C / SAM3U1C Devices) A1 VBG C6 PB22 F1 PB1 H6 PA15/PGMD7 A2 XIN C7 TMS/SWDIO F2 PB12 H7 PA18/PGMD10 A3 XOUT C8 NRSTB F3 VDDIO H8 PA24 A4 PB17 C9 JTAGSEL F4 PA31 H9 PA1/PGMRDY A5 PB21 C10 VDDBU F5 VDDIO H10 PA2/PGMNOE A6 PB23 D1 DFSDM F6 GND J1 PB6 A7 TCK/SWCLK D2 DHSDM F7 PB16 J2 PB8 A8 VDDIN D3 VDDPLL F8 PA6/PGMM2 J3 ADVREF A9 VDDOUT D4 VDDCORE F9 VDDCORE J4 PA30 A10 XIN32 D5 PB20 F10 PA7/PGMM3 J5 PB3 B1 VDDCORE D6 ERASE G1 PB11 J6 PA16/PGMD8 B2 GNDUTMI D7 TST G2 PB2 J7 PA19/PGMD11 B3 VDDUTMI D8 FWUP G3 PB0 J8 PA21/PGMD13 B4 PB10 D9 PA11/PGMD3 G4 PB13 J9 PA26 B5 PB18 D10 PA12/PGMD4 G5 VDDCORE J10 PA0/PGMNCMD B6 PB24 E1 PA29 G6 GND K1 PB7 B7 NRST E2 GND G7 PB15 K2 VDDANA B8 TDO/TRACESWO E3 PA28 G8 PA3/PGMNVALID K3 GNDANA B9 TDI E4 PB9 G9 PA5/PGMM1 K4 AD12BVREF B10 XOUT32 E5 GNDBU G10 PA4/PGMM0 K5 PB4 C1 DFSDP E6 VDDIO H1 VDDCORE K6 PA14/PGMD6 C2 DHSDP E7 VDDCORE H2 PB5 K7 PA17/PGMD9 C3 GNDPLL E8 PA10/PGMD2 H3 PA27 K8 PA20/PGMD12 C4 PB14 E9 PA9/PGMD1 H4 PA22/PGMD14 K9 PA23/PGMD15 C5 PB19 E10 PA8/PGMD0 H5 PA13/PGMD5 K10 PA25 16 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 5. Power Considerations 5.1 Power Supplies The SAM3U product power supply pins are the following:  VDDCORE pins: Power the core, the embedded memories and the peripherals; voltage range 1.62–1.95 V  VDDIO pins: Power the peripherals I/O lines; voltage range 1.62–3.6 V  VDDIN pin: Powers the voltage regulator  VDDOUT pin: Output of the voltage regulator  VDDBU pin: Powers the Slow Clock oscillator and a part of the System Controller; voltage range 1.62– 3.6V. VDDBU must be supplied before or at the same time as VDDIO and VDDCORE.  VDDPLL pin: Powers the PLL A, UPLL and 3–20 MHz Oscillator; voltage range 1.62–1.95 V  VDDUTMI pin: Powers the UTMI+ interface; voltage range 3.0–3.6 V, 3.3V nominal  VDDANA pin: Powers the ADC cells; voltage range 2.0–3.6 V Ground pins GND are common to VDDCORE and VDDIO pins power supplies. Separated ground pins are provided for VDDBU, VDDPLL, VDDUTMI and VDDANA. These ground pins are respectively GNDBU, GNDPLL, GNDUTMI and GNDANA. 5.2 Power-up Considerations 5.2.1 VDDIO Versus VDDCORE VDDIO must always be higher or equal to VDDCORE. VDDIO must reach its minimum operating voltage (1.60 V) before VDDCORE has reached VDDCORE(min). The minimum slope for VDDCORE is defined by (VDDCORE(min) - VT+) / tRST. If VDDCORE rises at the same time as VDDIO, the VDDIO rising slope must be higher than or equal to 5V/ms. If VDDCORE is powered by the internal regulator, all power-up considerations are met. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17 Figure 5-1. VDDCORE and VDDIO Constraints at Startup Supply (V) VDDIO VDDIO(min) VDDCORE VDDCORE(min) VT+ tRST Time (t) Core supply POR output SLCK 5.2.2 VDDIO Versus VDDIN At power-up, VDDIO needs to reach 0.6 V before VDDIN reaches 1.0 V. VDDIO voltage needs to be equal to or below (VDDIN voltage + 0.5 V). 5.3 Voltage Regulator The SAM3U embeds a voltage regulator that is managed by the Supply Controller. This internal regulator is intended to supply the internal core of SAM3U but can be used to supply other parts in the application. It features two different operating modes:  In Normal mode, the voltage regulator consumes less than 700 µA static current and draws 150 mA of output current. Internal adaptive biasing adjusts the regulator quiescent current depending on the required load current. In Wait mode or when the output current is low, quiescent current is only 7 µA.  In Shutdown mode, the voltage regulator consumes less than 1 µA while its output is driven internally to GND. The default output voltage is 1.80 V and the startup time to reach Normal mode is inferior to 400 µs. For adequate input and output power supply decoupling/bypassing, refer to Table 42-3, “1.8V Voltage Regulator Characteristics,” on page 1089. 5.4 Typical Powering Schematics The SAM3U supports a 1.62–3.6 V single supply mode. The internal regulator input connected to the source and its output feed VDDCORE. Figure 5-2, Figure 5-3, and Figure 5-4 show the power schematics. 18 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 5-2. Single Supply VDDBU VDDUTMI VDDANA VDDIO Main Supply (1.62–3.6 V) VDDIN Voltage Regulator VDDOUT VDDCORE VDDPLL Note: Restrictions: With Main Supply < 2.0 V, USB and ADC are not usable. With Main Supply ≥ 2.4V and < 3V, USB is not usable. With Main Supply ≥ 3V, all peripherals are usable. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 19 Figure 5-3. Core Externally Supplied VDDBU VDDUTMI VDDANA Main Supply (1.62–3.6 V) VDDIO VDDIN Voltage Regulator VDDOUT VDDCORE Supply (1.62–1.95 V) VDDCORE VDDPLL Note: 20 Restrictions: With Main Supply < 2.0 V, USB and ADC are not usable. With Main Supply ≥ 2.4V and < 3V, USB is not usable. With Main Supply ≥ 3V, all peripherals are usable. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 5-4. Backup Batteries Used FWUP SHDN Backup Batteries VDDBU VDDUTMI VDDANA VDDIO VDDIN Main Supply (1.62–3.6 V) Voltage Regulator VDDOUT VDDCORE VDDPLL Note: Restrictions With Main Supply < 2.0 V, USB and ADC are not usable. With Main Supply ≥ 2.4V and < 3V, USB is not usable. With Main Supply ≥ 3V, all peripherals are usable. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 21 5.5 Active Mode Active mode is the normal running mode with the core clock running from the fast RC oscillator, the main crystal oscillator or the PLLA. The power management controller can be used to adapt the frequency and to disable the peripheral clocks. 5.6 Low-power Modes The SAM3U has the following low-power modes: Backup, Wait, and Sleep. 5.6.1 Backup Mode The purpose of backup mode is to achieve the lowest power consumption possible in a system which is performing periodic wake-ups to perform tasks but not requiring fast startup time (< 0.5 ms). The Supply Controller, zero-power power-on reset, RTT, RTC, backup registers and 32 kHz oscillator (RC or crystal oscillator selected by software in the Supply Controller) are running. The regulator and the core supply are off. Backup mode is based on the Cortex-M3 deep-sleep mode with the voltage regulator disabled. The SAM3U Series can be woken up from this mode through the Force Wake-Up (FWUP) pin, and Wake-Up input pins WKUP0–15, Supply Monitor, RTT or RTC wake-up event. Current consumption is 2.5 µA typical on VDDBU. Backup mode can be entered by using the WFE instruction. The procedure to enter Backup mode using the WFE instruction is the following: 1. Write a 1 to the SLEEPDEEP bit in the Cortex-M3 processor System Control Register (SCR) (refer to Section 12.20.7 ”System Control Register”). 2. Execute the WFE instruction of the processor. Exit from Backup mode happens if one of the following enable wake-up events occurs: 5.6.2  Low level, configurable debouncing on FWUP pin  Level transition, configurable debouncing on pins WKUPEN0–15  SM alarm  RTC alarm  RTT alarm Wait Mode The purpose of the Wait mode is to achieve very low power consumption while maintaining the whole device in a powered state for a startup time of less than 10 µs. In this mode, the clocks of the core, peripherals and memories are stopped. However, the core, peripherals and memories power supplies are still powered. From this mode, a fast start up is available. This mode is entered via Wait for Event (WFE) instructions with LPM = 1 (Low Power Mode bit in PMC_FSMR). The Cortex-M3 is able to handle external events or internal events in order to wake up the core (WFE). This is done by configuring the external lines WKUP0–15 as fast startup wake-up pins (refer to Section 5.8 “Fast Startup”). RTC or RTT Alarm and USB wake-up events can be used to wake up the CPU (exit from WFE). Current Consumption in Wait mode is typically 15 µA on VDDIN if the internal voltage regulator is used or 8 µA on VDDCORE if an external regulator is used. The procedure to enter Wait mode is the following: 22 1. Select the 4/8/12 MHz fast RC oscillator as Main Clock 2. Set the LPM bit in PMC_FSMR 3. Execute the WFE instruction of the processor SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Note: 5.6.3 Internal Main clock resynchronization cycles are necessary between the writing of MOSCRCEN bit and the effective entry in Wait mode. Depending on the user application, waiting for MOSCRCEN bit to be cleared is recommended to ensure that the core will not execute undesired instructions. Sleep Mode The purpose of sleep mode is to optimize power consumption of the device versus response time. In this mode, only the core clock is stopped. The peripheral clocks can be enabled. This mode is entered via Wait for Interrupt (WFI) or WFE instructions with LPM = 0 in PMC_FSMR. The processor can be woken up from an interrupt if WFI instruction of the Cortex-M3 is used, or from an event if the WFE instruction is used to enter this mode. 5.6.4 Low-power Mode Summary Table The modes detailed above are the main low-power modes. Each part can be set to on or off separately and wake up sources can be individually configured. Table 5-1 shows a summary of the configurations of the low-power modes. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 23 Table 5-1. Low Power Mode Configuration Summary SUPC, 32 kHz Osc., RTC, RTT, GPBR, Core POR (VDDBU Memory Region) Regulator Peripherals Mode Backup Mode Mode Entry Potential Wake-up Sources Core at Wake-up PIO State While in Low PIO State at Consumption Wake-up (2) (3) Time(1) Power Mode Wake-up ON FWUP pin Pins WKUP0–15 WFE OFF OFF SM alarm SHDN = 0 (Not powered) + SLEEPDEEP = 1 RTC alarm RTT alarm ON Any event from: - Fast startup through pins WKUP0–15 ON Powered + SLEEPDEEP = 0 - RTC alarm SHDN = 1 (Not clocked) - RTT alarm + LPM = 1 - USB wake-up ON Entry mode = WFI interrupt only; Entry mode = WFE any enabled interrupt and/or WFE or WFI ON Powered(7) Any event from: Previous state + SLEEPDEEP = 0 Clocked back Unchanged SHDN = 1 (Not clocked) - Fast startup through pins WKUP0–15 saved + LPM = 0 - RTC alarm - RTT alarm - USB wake-up Reset PIOA & PIOB & Previous state PIOC saved Inputs with pull-ups 2.5 µA typ(4) < 0.5 ms WFE Wait Mode Sleep Mode Notes: Clocked back Previous state Unchanged 13 µA/20 µA(5) < 10 µs saved (6) (6) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1. When considering wake-up time, the time required to start the PLL is not taken into account. Once started, the device works with the 4/8/12 MHz Fast RC oscillator. The user has to add the PLL startup time if it is needed in the system. The wake-up time is defined as the time taken for wake-up until the first instruction is fetched. 2. The external loads on PIOs are not taken into account in the calculation. 3. BOD current consumption is not included. 4. Current consumption on VDDBU. 5. 13 µA total current consumption - without using internal voltage regulator. 20 µA total current consumption - using internal voltage regulator. 6. Depends on MCK frequency. 7. In this mode the core is supplied and not clocked but some peripherals can be clocked. 24 5.7 Wake-up Sources The wake-up events allow the device to exit Backup mode. When a wake-up event is detected, the Supply Controller performs a sequence which automatically reenables the core power supply. See Figure 18-7 “Wake Up Sources” on page 273. 5.8 Fast Startup The SAM3U device allows the processor to restart in a few microseconds while the processor is in Wait mode. A fast startup can occur upon detection of a low level on one of the 19 wake-up inputs (WKUP0 to 15 + RTC + RTT + USB). The fast restart circuitry (shown in Figure 27-3 “Fast Startup Circuitry” on page 454) is fully asynchronous and provides a fast startup signal to the Power Management Controller. As soon as the fast startup signal is asserted, the PMC automatically restarts the embedded 4/8/12 MHz fast RC oscillator, switches the master clock on this 4 MHz clock by default and reenables the processor clock. 6. Input/Output Lines The SAM3U has different kinds of input/output (I/O) lines, such as general purpose I/Os (GPIO) and system I/Os. GPIOs can have alternate functions thanks to multiplexing capabilities of the PIO controllers. The same GPIO line can be used whether it is in IO mode or used by the multiplexed peripheral. System I/Os are pins such as test pin, oscillators, erase pin, analog inputs or debug pins. With a few exceptions, the I/Os have input Schmitt triggers. Refer to the footnotes associated with “PIO Controller - PIOA - PIOB - PIOC” on page 7 within Table 3-1, “Signal Description List”. 6.1 General Purpose I/O Lines (GPIO) GPIO Lines are managed by PIO controllers. All I/Os have several input or output modes such as, pull-up, input Schmitt triggers, multi-drive (open-drain), glitch filters, debouncing or input change interrupt. Programming of these modes is performed independently for each I/O line through the PIO controller user interface. For more details, refer to Section 29. ”Parallel Input/Output Controller (PIO)”. The input output buffers of the PIO lines are supplied through VDDIO power supply rail. The SAM3U embeds high-speed pads able to handle up to 65 MHz for HSMCI and SPI clock lines and 35 MHz on other lines. See Section 42.9 ”AC Characteristics” for more details. Typical pull-up value is 100 kΩ for all I/Os. Each I/O line also embeds an ODT (On-Die Termination) (see Figure 6-1). ODT consists of an internal series resistor termination scheme for impedance matching between the driver output (SAM3) and the PCB track impedance preventing signal reflection. The series resistor helps to reduce I/Os switching current (di/dt) thereby reducing in turn, EMI. It also decreases overshoot and undershoot (ringing) due to inductance of interconnect between devices or between boards. In conclusion, ODT helps reducing signal integrity issues. Figure 6-1. On-Die Termination Schematic Z0 ~ ZO + RODT ODT 36 Ω Typ. RODT Receiver SAM3 Driver with ZO ~ 10 Ω PCB Track Z0 ~ 50 Ω SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 25 6.2 System I/O Lines System I/O lines are pins used by oscillators, test mode, reset, flash erase and JTAG to name but a few. 6.3 Serial Wire JTAG Debug Port (SWJ-DP) The SWJ-DP pins are TCK/SWCLK, TMS/SWDIO, TDO/TRACESWO, TDI and commonly provided on a standard 20-pin JTAG connector defined by ARM. For more details about voltage reference and reset state, refer to Table 3-1, “Signal Description List”. The JTAGSEL pin is used to select the JTAG boundary scan when asserted at a high level. It integrates a permanent pull-down resistor of about 15 kΩ to GNDBU, so that it can be left unconnected for normal operations. By default, the JTAG Debug Port is active. If the debugger host wants to switch to the Serial Wire Debug Port, it must provide a dedicated JTAG sequence on TMS/SWDIO and TCK/SWCLK which disables the JTAG-DP and enables the SW-DP. When the Serial Wire Debug Port is active, TDO/TRACESWO can be used for trace. The asynchronous TRACE output (TRACESWO) is multiplexed with TDO. So the asynchronous trace can only be used with SW-DP, not JTAG-DP. All the JTAG signals are supplied with VDDIO except JTAGSEL, supplied by VDDBU. 6.4 Test Pin The TST pin is used for JTAG Boundary Scan Manufacturing Test or fast flash programming mode of the SAM3U series. The TST pin integrates a permanent pull-down resistor of about 15 kΩ to GND, so that it can be left unconnected for normal operations. To enter fast programming mode, see Section 21. ”Fast Flash Programming Interface (FFPI)”. For more on the manufacturing and test mode, refer to Section 13. ”Debug and Test Features”. 6.5 NRST Pin The NRST pin is bidirectional. It is handled by the on-chip reset controller and can be driven low to provide a reset signal to the external components or asserted low externally to reset the microcontroller. It will reset the Core and the peripherals, except the Backup region (RTC, RTT and Supply Controller). There is no constraint on the length of the reset pulse and the reset controller can guarantee a minimum pulse length. The NRST pin integrates a permanent pull-up resistor to VDDIO of about 100 kΩ. 6.6 NRSTB Pin The NRSTB pin is input only and enables asynchronous reset of the SAM3U when asserted low. The NRSTB pin integrates a permanent pull-up resistor of about 15 kΩ. This allows connection of a simple push button on the NRSTB pin as a system-user reset. In all modes, this pin will reset the chip including the Backup region (RTC, RTT and Supply Controller). It reacts as the Power-on reset. It can be used as an external system reset source. In harsh environments, it is recommended to add an external capacitor (10 nF) between NRSTB and VDDBU. (For filtering values refer to Section 42.9.2 ”I/O Characteristics”.) It embeds an anti-glitch filter. 6.7 ERASE Pin The ERASE pin is used to reinitialize the Flash content and some of its NVM bits. The ERASE pin and the ROM code ensure an in-situ reprogrammability of the Flash content without the use of a debug tool. When the security bit is activated, the ERASE pin provides the capability to reprogram the Flash content. It integrates a permanent pull-down resistor of about 15 kΩ to GND, so that it can be left unconnected for normal operations. 26 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 This pin is debounced by SCLK to improve the glitch tolerance. When the ERASE pin is tied high during less than 100 ms, it is not taken into account. The pin must be tied high during more than 220 ms to perform the reinitialization of the Flash. Even in all low power modes, asserting the pin will automatically start up the chip and erase the Flash. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 27 7. Architecture 7.1 APB/AHB Bridges The SAM3U product embeds two separated APB/AHB bridges:  Low speed bridge  High speed bridge This architecture enables to make concurrent accesses on both bridges. All the peripherals are on the low-speed bridge except SPI, SSC and HSMCI. The UART, 10-bit ADC (ADC), 12-bit ADC (ADC12B), TWI0–1, USART0–3, and PWM have dedicated channels for the Peripheral DMA Controller (PDC) channels. These peripherals can not use the DMA Controller. The high speed bridge regroups the SSC, SPI and HSMCI. These three peripherals do not have PDC channels but can use the DMA with the internal FIFO for channel buffering. Note that the peripherals of the two bridges are clocked by the same source: MCK. 7.2 Matrix Masters The Bus Matrix of the SAM3U device manages five masters, which means that each master can perform an access concurrently with others to an available slave. Each master has its own decoder and specifically defined bus. In order to simplify the addressing, all the masters have the same decoding. Table 7-1. 7.3 List of Bus Matrix Masters Master 0 Cortex-M3 Instruction/Data Bus Master 1 Cortex-M3 System Bus Master 2 Peripheral DMA Controller (PDC) Master 3 USB Device High Speed DMA Master 4 DMA Controller Matrix Slaves The Bus Matrix of the SAM3U manages 10 slaves. Each slave has its own arbiter, allowing a different arbitration per slave. Table 7-2. 28 List of Bus Matrix Slaves Slave 0 Internal SRAM0 Slave 1 Internal SRAM1 Slave 2 Internal ROM Slave 3 Internal Flash 0 Slave 4 Internal Flash 1 Slave 5 USB Device High Speed Dual Port RAM (DPR) Slave 6 NAND Flash Controller RAM Slave 7 External Bus Interface Slave 8 Low Speed Peripheral Bridge Slave 9 High Speed Peripheral Bridge SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 7.4 Master to Slave Access All the Masters can normally access all the Slaves. However, some paths do not make sense, for example allowing access from the USB Device High speed DMA to the Internal Peripherals. Thus, these paths are forbidden or simply not wired, and shown as “–” in Table 7-3 below. Table 7-3. SAM3U Master to Slave Access Masters Slaves 0 1 2 3 4 Cortex-M3 Instruction/Data Bus Cortex-M3 System Bus Peripheral DMA Controller (PDC) USB Device High Speed DMA DMA Controller 0 Internal SRAM0 – X X X X 1 Internal SRAM1 – X X X X 2 Internal ROM X – X X X 3 Internal Flash 0 X – – – – 4 Internal Flash 1 X – – – – – X – – – 5 USB Device High Speed Dual Port RAM (DPR) 6 NAND Flash Controller RAM – X X X X 7 External Bus Interface – X X X X 8 Low Speed Peripheral Bridge – X X – – 9 High Speed Peripheral Bridge – X X – – SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 29 7.5 DMA Controller  Acting as one Matrix Master  Embeds 4 channels: ̶ 3 channels with 8 bytes/FIFO for Channel Buffering ̶ 1 channel with 32 bytes/FIFO for Channel Buffering  Linked List support with Status Write Back operation at End of Transfer  Word, HalfWord, Byte transfer support  Handles high speed transfer of SPI, SSC and HSMCI (peripheral to memory, memory to peripheral)  Memory to memory transfer  Can be triggered by PWM and T/C which enables to generate waveforms though the External Bus Interface The DMA controller can handle the transfer between peripherals and memory and so receives the triggers from the peripherals listed below. The hardware interface numbers are also given in Table 7-4. Table 7-4. 7.6 DMA Controller Instance Name Channel T/R DMA Channel HW Interface Number HSMCI Transmit/Receive 0 SPI Transmit 1 SPI Receive 2 SSC Transmit 3 SSC Receive 4 PWM Event Line 0 Trigger 5 PWM Event Line 1 Trigger 6 TIO Output of TImer Counter Channel 0 Trigger 7 Peripheral DMA Controller  Handles data transfer between peripherals and memories  Nineteen channels   ̶ Two for each USART ̶ Two for the UART ̶ Two for each Two Wire Interface ̶ One for the PWM ̶ One for each Analog-to-Digital Converter Low bus arbitration overhead ̶ One Master Clock cycle needed for a transfer from memory to peripheral ̶ Two Master Clock cycles needed for a transfer from peripheral to memory Next Pointer management for reducing interrupt latency requirement The PDC handles transfer requests from the channel according to the priorities (low to high priorities) defined in Table 7-5. 30 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 7-5. Peripheral DMA Controller Instance Name Channel Transmit/Receive TWI1 Transmit TWI0 Transmit PWM Transmit UART Transmit USART3 Transmit USART2 Transmit USART1 Transmit USART0 Transmit TWI0 Receive TWI1 Receive UART Receive USART3 Receive USART2 Receive USART1 Receive USART0 Receive ADC Receive ADC12B Receive SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 31 8. Memories 8.1 Memory Mapping Figure 8-1. SAM3U Memory Mapping Code 0x00000000 0x00000000 Address memory space Peripherals 0x40000000 MCI Boot Memory 17 0x40004000 Code 0x00080000 SSC Internal Flash 0 21 0x40008000 0x20000000 0x00100000 SPI Internal Flash 1 20 0x4000C000 Internal SRAM 0x00180000 Reserved Internal ROM 0x40080000 0x40000000 0x00200000 Reserved 0x20000000 1 Mbyte bit band region +0x40 Peripherals 0x1FFFFFFF Internal SRAM +0x80 0x60000000 SRAM0 0x20180000 0x20200000 24 18 19 PWM 25 0x40090000 0xE0000000 USART0 Undefined 0x22000000 13 0x40094000 System 32 Mbytes bit band alias USART1 14 0x40098000 0xFFFFFFFF USART2 Undefined 0x40000000 0x400E0000 System Controller USART3 Reserved MATRIX 0x400A4000 0x400E0400 UDPHS PMC Chip Select 0 5 0x400E0600 0x61000000 ADC12B 8 0x400E0740 0x62000000 ADC DMAC EFC0 6 0x400E0A00 0x64000000 0x400E0C00 0x68000000 Reserved 7 0x400E0000 10 0x400E2600 11 0x40100000 12 0x42000000 1 0x44000000 System Controller PIOA NFC 0x400E0E00 reserved 0x400E1000 0x69000000 PIOB 0x9FFFFFFF Reserved Reserved PIOC 0x400E1200 RSTC block ID +0x10 0x60000000 RTT 3 WDT 4 +0x60 RTC +0x90 2 SYSC GPBR 0x400E1400 reserved 0x4007FFFF SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32 Mbytes bit band alias Reserved SUPC +0x30 +0x50 28 0x400B3FFF EFC1 reserved 27 0x400B0000 0x400E0800 0x63000000 Chip Select 3 26 0x400AC000 CHIPID Chip Select 2 29 0x400A8000 UART Chip Select 1 16 0x400A0000 0x400E0200 External SRAM 15 0x4009C000 SMC 32 TC2 0x4008C000 Reserved UDPHS (DMA) peripheral 23 TC0 TWI1 NFC (SRAM) offset TC1 0x40088000 0xA0000000 0x20100000 0x60000000 22 TC0 TWI0 SRAM1 0x24000000 TC0 0x40084000 External SRAM 0x20080000 TC0 1 Mbyte bit band region The memories are described in Section 8.2 ”Embedded Memories” and Section 8.3 ”External Memories”. 8.2 Embedded Memories 8.2.1 Internal SRAM Table 8-1 shows the embedded high-speed SRAM for the various devices. Table 8-1. Embedded High-speed SRAM per Device Device Pin Count SRAM0 (KB) SRAM1 (KB) NFC SRAM (KB) Total SRAM (KB) SAM3U4 144/100 32 16 4 52 SAM3U2 144/100 16 16 4 36 SAM3U1 144/100 8 8 4 20 SRAM0 is accessible over System Cortex-M3 bus at address 0x2000 0000 and SRAM1 at address 0x2008 0000. The user can see the SRAM as contiguous at 0x20078000–0x20083FFF (SAM3U4), 0x2007C000–0x20083FFFF (SAM3U2) or 0x2007E000–0x20081FFFF (SAM3U1). SRAM0 and SRAM1 are in the bit band region. The bit band alias region is from 0x2200 0000 and 0x23FF FFFF. The NAND Flash Controller (NFC) embeds 4224 bytes of internal SRAM. If the NFC is not used, these 4224 bytes can be used as general-purpose SRAM. It can be seen at address 0x2010 0000. 8.2.2 Internal ROM The SAM3U product embeds an Internal ROM, which contains the SAM-BA® Boot and FFPI program. At any time, the ROM is mapped at address 0x0018 0000. 8.2.3 Embedded Flash 8.2.3.1 Flash Overview Table 8-2 shows the Flash organization for the various devices. Table 8-2. Embedded Flash Memory Organization per Device Device Flash Size Number of Banks Pages per Bank Page Size Plane SAM3U4 256 Kbytes 2 512 256 bytes Dual SAM3U2 128 Kbytes 1 512 256 bytes Single SAM3U1 64 Kbytes 1 256 256 bytes Single The Flash contains a 128-byte write buffer, accessible through a 32-bit interface. 8.2.3.2 Flash Power Supply The Flash is supplied by VDDCORE. 8.2.3.3 Enhanced Embedded Flash Controller The Enhanced Embedded Flash Controller (EEFC) manages accesses performed by the masters of the system. It enables reading the Flash and writing the write buffer. It also contains a User Interface, mapped within the Memory Controller on the APB. The Enhanced Embedded Flash Controller ensures the interface of the Flash block with the 32-bit internal bus. Its 128-bit wide memory interface increases performance. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 33 The user can choose between high performance or lower current consumption by selecting either 128-bit or 64-bit access. It also manages the programming, erasing, locking and unlocking sequences of the Flash using a full set of commands. One of the commands returns the embedded Flash descriptor definition that informs the system about the Flash organization, thus making the software generic. The SAM3U4 (256 Kbytes internal Flash version) embeds two EEFC (EEFC0 for Flash0 and EEFC1 for Flash1) whereas the SAM3U2/1 embeds one EEFC. 8.2.3.4 Lock Regions Several lock bits are used to protect write and erase operations on lock regions. A lock region is composed of several consecutive pages, and each lock region has its associated lock bit. Table 8-3. Number of Lock Bits Product Number of Embedded EEFCs Number of Lock Bits Managed per EEFC Number of Protected Flash Regions(1) Number of Lock Regions Number of Pages per Lock Region Page Size Lock Region Size SAM3U4 2 16 32 32 32 256 bytes 8 Kbytes SAM3U2 1 16 32 16 32 256 bytes 8 Kbytes SAM3U1 1 8 8 8 32 256 bytes 8 Kbytes Note: 1. Protected against inadvertent Flash erasing or programming commands. If a locked-region’s erase or program command occurs, the command is aborted and the EEFC triggers an interrupt. The lock bits are software programmable through the EEFC User Interface. The command “Set Lock Bit” enables the protection. The command “Clear Lock Bit” unlocks the lock region. Asserting the ERASE pin clears the lock bits, thus unlocking the entire Flash. 8.2.3.5 Security Bit Feature The SAM3U features a security bit, based on a specific General Purpose NVM bit (GPNVM bit 0). When the security is enabled, any access to the Flash, SRAM, Core Registers and Internal Peripherals either through the ICE interface or through the Fast Flash Programming Interface, is forbidden. This ensures the confidentiality of the code programmed in the Flash. This security bit can only be enabled, through the command “Set General Purpose NVM Bit 0” of the EEFC User Interface. Disabling the security bit can only be achieved by asserting the ERASE pin at 1, and after a full Flash erase is performed. When the security bit is deactivated, all accesses to the Flash, SRAM, Core Registers and Internal Peripherals either through the ICE interface or through the Fast Flash Programming Interface are permitted. It is important to note that the assertion of the ERASE pin should always be longer than 200 ms. As the ERASE pin integrates a permanent pull-down, it can be left unconnected during normal operation. However, it is safer to connect it directly to GND for the final application. 8.2.3.6 Calibration Bits NVM bits are used to calibrate the brownout detector and the voltage regulator. These bits are factory configured and cannot be changed by the user. The ERASE pin has no effect on the calibration bits. 8.2.3.7 Unique Identifier Each device integrates its own 128-bit unique identifier. These bits are factory configured and cannot be changed by the user. The ERASE pin has no effect on the unique identifier. 34 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 8.2.3.8 Fast Flash Programming Interface (FFPI) The FFPI allows programming the device through either a serial JTAG interface or through a multiplexed fullyhandshaked parallel port. It allows gang programming with market-standard industrial programmers. The FFPI supports read, page program, page erase, full erase, lock, unlock and protect commands. The FFPI is enabled and the Fast Programming Mode is entered when TST, NRSTB and FWUP pins are tied high during power up sequence and if all supplies are provided externally (do not use internal regulator for VDDCORE). Please note that since the FFPI is a part of the SAM-BA Boot Application, the device must boot from the ROM. 8.2.3.9 SAM-BA Boot The SAM-BA Boot is a default Boot Program which provides an easy way to program in-situ the on-chip Flash memory. The SAM-BA Boot Assistant supports serial communication via the UART and USB. The SAM-BA Boot provides an interface with SAM-BA Graphic User Interface (GUI). The SAM-BA Boot is in ROM and is mapped in Flash at address 0x0 when GPNVM bit 1 is set to 0. 8.2.3.10 GPNVM Bits The SAM3U2/1 features two GPNVM bits whereas SAM3U4 features three GPNVM bits. These bits can be cleared or set respectively through the commands “Clear GPNVM Bit” and “Set GPNVM Bit” of the EEFC User Interface. The SAM3U4 is equipped with two EEFC, EEFC0 and EEFC1. EEFC1 does not feature the GPNVM bits. The GPNVM embedded on EEFC0 applies to the two blocks in the SAM3U4. The GPNVM2 is used only to swap the Flash 0 and Flash 1:  If GPNVM2 = ENABLE, the Flash 1 is mapped at address 0x0008_0000 (Flash 1 and Flash 0 are continuous).  If GPNVM2 = DISABLE, the Flash 0 is mapped at address 0x0008_0000 (Flash 0 and Flash 1 are continuous). Table 8-4. General-purpose Non-volatile Memory Bits GPNVMBit[#] 8.2.4 Function 0 Security bit 1 Boot mode selection (boot always at 0x00) on ROM or Flash 2 Flash selection (Flash 0 or Flash 1) Only on SAM3U4 (256 Kbytes internal Flash version) Boot Strategies The system always boots at address 0x0. To ensure a maximum boot possibilities the memory layout can be changed via GPNVM. A general purpose NVM (GPNVM1) bit is used to boot either on the ROM (default) or from the Flash. Setting the GPNVM Bit 1 selects the boot from the Flash, clearing it selects the boot from the ROM. Asserting ERASE clears the GPNVM Bit 1 and thus selects the boot from the ROM by default. GPNVM2 enables to select if Flash 0 or Flash 1 is used for the boot. Setting the GPNVM2 bit selects the boot from Flash 1, clearing it selects the boot from Flash 0. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35 8.3 External Memories The SAM3U offers an interface to a wide range of external memories and to any parallel peripheral. 8.3.1 Static Memory Controller  8 or 16-bit Data Bus  Up to 24-bit Address Bus (up to 16 Mbytes linear per chip select)  Up to 4 chip selects, Configurable Assignment  Multiple Access Modes supported ̶ Byte Write or Byte Select Lines  Multiple device adaptability  Multiple Wait State Management ̶  8.3.2 8.3.3 ̶ Programmable Wait State Generation ̶ External Wait Request ̶ Programmable Data Float Time Slow Clock mode supported NAND Flash Controller  Handles automatic Read/Write transfer through 4224 bytes SRAM buffer  DMA support  Supports SLC NAND Flash technology  Programmable timing on a per chip select basis  Programmable Flash Data width 8-bit or 16-bit NAND Flash Error Corrected Code Controller  Integrated in the NAND Flash Controller  Single bit error correction and 2-bit Random detection  Automatic Hamming Code Calculation while writing ̶  36 Control signals programmable setup, pulse and hold time for each Memory Bank ECC value available in a register Automatic Hamming Code Calculation while reading ̶ Error Report, including error flag, correctable error flag and word address being detected erroneous ̶ Supports 8 or 16-bit NAND Flash devices with 512, 1024, 2048, or 4096-byte pages SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 9. Real-time Event Management The events generated by peripherals are designed to be directly routed to peripherals managing/using these events without processor intervention. Peripherals receiving events contain logic by which to determine and perform the action required. 9.1 Embedded Characteristics 9.2  Timers, IO peripherals generate event triggers which are directly routed to event managers such as ADC, for example, to start measurement/conversion without processor intervention.  UART, USART, SPI, TWI, ADC (10-bit ADC and 12-bit ADC), PIO also generate event triggers directly connected to Peripheral DMA Controller (PDC) for data transfer without processor intervention. Real-time Event Mapping Table 9-1. Real-time Event Mapping List Function Application Description Event Source Event Destination PIO (ADTRG) TC: TIOA0 Trigger source selection in 10-bit ADC (1) ADC TC: TIOA1 TC: TIOA2 General-purpose PIO (AD12BTRG) Measurement trigger TC: TIOA0 Trigger source selection in 12-bit ADC (2) ADC12B TC: TIOA1 TC: TIOA2 ADC-PWM synchronization (3)(4) Trigger source selection in ADC Motor control PWM Event Line 0 Notes: 1. 2. 3. 4. 5. General-purpose PWM Event Line 1 ADC12B-PWM synchronization (3)(4) Trigger source selection in ADC12B Direct Memory Access ADC (1) PWM Event Line 0 ADC12B (2) PWM Event Line 1 Peripheral trigger event generation to transfer data to/from system memory (5) USART/UART, PWM, TWI, ADC, ADC12B PDC Refer to Section 41.5.5 ”Conversion Triggers” and Section 41.6.2 ”ADC Mode Register” (ADC_MR). Refer to Section 40.5.8 ”Conversion Triggers” and Section 40.6.2 ”ADC12B Mode Register” (ADC12B_MR). Refer to Section 37.7.31 ”PWM Comparison x Value Register” (PWM_CMPVx). Refer to Section 37.6.3 ”PWM Comparison Units” and Section 37.6.4 ”PWM Event Lines”. Refer to Section 25. ”Peripheral DMA Controller (PDC)”. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 37 10. System Controller The System Controller is a set of peripherals, which allow handling of key elements of the system, such as but not limited to power, resets, clocks, time, interrupts, and watchdog. (Refer to Figure 18-1 “Supply Controller Block Diagram” on page 265.) The System Controller User Interface also embeds the registers used to configure the Matrix. 10.1 System Controller and Peripheral Mapping Please refer to Figure 8-1 “SAM3U Memory Mapping” on page 32. All the peripherals are in the bit band region and are mapped in the bit band alias region. 10.2 Power-on-Reset, Brownout and Supply Monitor The SAM3U embeds three features to monitor, warn and/or reset the chip:  Power-on-Reset on VDDBU  Brownout Detector on VDDCORE  Supply Monitor on VDDUTMI 10.2.1 Power-on-Reset on VDDBU The Power-on-Reset monitors VDDBU. It is always activated and monitors voltage at start up but also during power down. If VDDBU goes below the threshold voltage, the entire chip is reset. For more information, refer to Section 42. ”Electrical Characteristics”. 10.2.2 Brownout Detector on VDDCORE The Brownout Detector monitors VDDCORE. It is active by default. It can be deactivated by software through the Supply Controller (SUPC_MR). It is especially recommended to disable it during low-power modes such as wait or sleep modes. If VDDCORE goes below the threshold voltage, the reset of the core is asserted. For more information, refer to Section 18. ”Supply Controller (SUPC)” and Section 42. ”Electrical Characteristics”. 10.2.3 Supply Monitor on VDDUTMI The Supply Monitor monitors VDDUTMI. It is not active by default. It can be activated by software and is fully programmable with 16 steps for the threshold (between 1.9V to 3.4V). It is controlled by the Supply Controller. A sample mode is possible. It allows to divide the supply monitor power consumption by a factor of up to 2048. For more information, refer to Section 18. ”Supply Controller (SUPC)” and Section 42. ”Electrical Characteristics”. 38 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 11. Peripherals 11.1 Peripheral Identifiers Table 11-1 defines the Peripheral Identifiers of the SAM3U. A peripheral identifier is required for the control of the peripheral interrupt with the Nested Vectored Interrupt Controller and for the control of the peripheral clock with the Power Management Controller. Note that some peripherals are always clocked. Please refer to the table below. Table 11-1. Peripheral Identifiers Instance ID Instance Name NVIC Interrupt PMC Clock Control 0 SUPC X Supply Controller 1 RSTC X Reset Controller 2 RTC X Real-time Clock 3 RTT X Real-time Timer 4 WDT X Watchdog Timer 5 PMC X Power Management Controller 6 EEFC0 X Enhanced Embedded Flash Controller 0 7 EEFC1 X Enhanced Embedded Flash Controller 1 8 UART X X Universal Asynchronous Receiver Transmitter 9 SMC X X Static Memory Controller 10 PIOA X X Parallel I/O Controller A 11 PIOB X X Parallel I/O Controller B 12 PIOC X X Parallel I/O Controller C 13 USART0 X X Universal Synchronous Asynchronous Receiver Transmitter 0 14 USART1 X X Universal Synchronous Asynchronous Receiver Transmitter 1 15 USART2 X X Universal Synchronous Asynchronous Receiver Transmitter 2 16 USART3 X X Universal Synchronous Asynchronous Receiver Transmitter 3 17 HSMCI X X High Speed Multimedia Card Interface 18 TWI0 X X Two-Wire Interface 0 19 TWI1 X X Two-Wire Interface 1 20 SPI X X Serial Peripheral Interface 21 SSC X X Synchronous Serial Controller 22 TC0 X X Timer Counter 0 23 TC1 X X Timer Counter 1 24 TC2 X X Timer Counter 2 25 PWM X X Pulse Width Modulation Controller 26 ADC12B X X 12-bit Analog-to-Digital Converter 27 ADC X X 10-bit Analog-to-Digital Converter 28 DMAC X X DMA Controller 29 UDPHS X X USB High Speed Device Port Instance Description SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39 11.2 Peripheral Signal Multiplexing on I/O Lines The SAM3U features three PIO controllers (PIOA, PIOB, and PIOC) that multiplex the I/O lines of the peripheral set. Each PIO controller controls up to 32 lines. Each line can be assigned to one of two peripheral functions, A or B. The multiplexing tables in the following pages define how the I/O lines of peripherals A and B are multiplexed on the PIO controllers. Note that some output-only peripheral functions might be duplicated within the tables. 40 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 11.2.1 PIO Controller A Multiplexing Table 11-2. I/O Line Multiplexing on PIO Controller A (PIOA) Peripheral A Peripheral B Extra Function PA0 TIOB0 NPCS1 WKUP0 PA1 TIOA0 NPCS2 WKUP1(1)(2)(3) PA2 TCLK0 ADTRG WKUP2(1)(2)(3) PA3 MCCK PCK1 PA4 MCCDA PWMH0 PA5 MCDA0 PWMH1 PA6 MCDA1 PWMH2 PA7 MCDA2 PWML0 PA8 MCDA3 PWML1 PA9 TWD0 PWML2 WKUP3(1)(2)(3) PA10 TWCK0 PWML3 WKUP4(1)(2)(3) PA11 URXD PWMFI0 PA12 UTXD PWMFI1 PA13 MISO PA14 MOSI PA15 SPCK PWMH2 PA16 NPCS0 NCS1 WKUP5(1)(2)(3) PA17 SCK0 AD12BTRG WKUP6(1)(2)(3) PA18 TXD0 PWMFI2 WKUP7(1)(2)(3) PA19 RXD0 NPCS3 WKUP8(1)(2)(3) PA20 TXD1 PWMH3 WKUP9(1)(2)(3) PA21 RXD1 PCK0 WKUP10(1)(2)(3) PA22 TXD2 RTS1 AD12B0(5) PA23 RXD2 CTS1 PA24 (4) TWD1 SCK1 WKUP11(1)(2)(3) WKUP12(1)(2)(3) PA25 TWCK1(4) SCK2 PA26 TD TCLK2 PA27 RD PCK0 PA28 TK PWMH0 PA29 RK PWMH1 PA30 TF TIOA2 PA31 RF TIOB2 Notes: 1. 2. 3. 4. 5. Comments (1)(2)(3) AD12B1(5) Wake-Up source in Backup mode (managed by the SUPC) Fast startup source in Wait mode (managed by the PMC) WKUPx can be used if PIO controller defines the I/O line as "input". Only on 144-pin version To select this extra function, refer to Section 40.4.3 “Analog Inputs”. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41 11.2.2 PIO Controller B Multiplexing Table 11-3. I/O Line Peripheral A Peripheral B Extra Function Comments (1)(2)(3) PB0 PWMH0 A2 WKUP13 PB1 PWMH1 A3 WKUP14(1)(2)(3) PB2 PWMH2 A4 WKUP15(1)(2)(3) PB3 PWMH3 A5 AD12B2(4) PB4 TCLK1 A6 AD12B3(4) PB5 TIOA1 A7 AD0(5) PB6 TIOB1 D15 AD1(5) PB7 RTS0 A0/NBS0 AD2(5) PB8 CTS0 A1 AD3(5) PB9 D0 DTR0 PB10 D1 DSR0 PB11 D2 DCD0 PB12 D3 RI0 PB13 D4 PWMH0 PB14 D5 PWMH1 PB15 D6 PWMH2 PB16 D7 PWMH3 PB17 NANDOE PWML0 PB18 NANDWE PWML1 PB19 NRD PWML2 PB20 NCS0 PWML3 PB21 A21/NANDALE RTS2 PB22 A22/NANDCLE CTS2 PB23 NWR0/NWE PCK2 PB24 NANDRDY PCK1 PB25 D8 PWML0 144-pin version only PB26 D9 PWML1 144-pin version only PB27 D10 PWML2 144-pin version only PB28 D11 PWML3 144-pin version only PB29 D12 144-pin version only PB30 D13 144-pin version only PB31 D14 144-pin version only Notes: 42 Multiplexing on PIO Controller B (PIOB) 1. 2. 3. 4. 5. Wake-Up source in Backup mode (managed by the SUPC) Fast startup source in Wait mode (managed by the PMC) WKUPx can be used if PIO controller defines the I/O line as "input". To select this extra function, refer to Section 40.4.3 “Analog Inputs”. To select this extra function, refer to Section 41.4.3 “Analog Inputs”. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 11.2.3 PIO Controller C Multiplexing Table 11-4. Multiplexing on PIO Controller C (PIOC) I/O Line Peripheral A PC0 A2 144-pin version only PC1 A3 144-pin version only PC2 A4 144-pin version only PC3 A5 NPCS1 144-pin version only PC4 A6 NPCS2 144-pin version only PC5 A7 NPCS3 144-pin version only PC6 A8 PWML0 144-pin version only PC7 A9 PWML1 144-pin version only PC8 A10 PWML2 144-pin version only PC9 A11 PWML3 144-pin version only PC10 A12 CTS3 144-pin version only PC11 A13 RTS3 144-pin version only PC12 NCS1 TXD3 144-pin version only PC13 A2 RXD3 144-pin version only PC14 A3 NPCS2 PC15 Peripheral B Extra Function NWR1/NBS1 144-pin version only (1) 144-pin version only (1) AD12B5 144-pin version only AD12B4 PC16 NCS2 PC17 NCS3 AD12B6(1) 144-pin version only PC18 NWAIT AD12B7(1) 144-pin version only PC19 SCK3 PC20 A14 144-pin version only PC21 A15 144-pin version only PC22 A16 144-pin version only PC23 A17 144-pin version only PC24 A18 PWMH0 144-pin version only PC25 A19 PWMH1 144-pin version only PC26 A20 PWMH2 144-pin version only PC27 A23 PWMH3 PC28 PWML3 Comments NPCS1 144-pin version only 144-pin version only MCDA4 AD4 (2) 144-pin version only PC29 PWML0 MCDA5 AD5(2) 144-pin version only PC30 PWML1 MCDA6 AD6(2) 144-pin version only MCDA7 (2) 144-pin version only PC31 Notes: PWML2 AD7 1. To select this extra function, refer to Section 40.4.3 “Analog Inputs”. 2. To select this extra function, refer to Section 41.4.3 “Analog Inputs”. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 43 12. ARM Cortex-M3 Processor 12.1 About this section This section provides the information required for application and system-level software development. It does not provide information on debug components, features, or operation. This material is for microcontroller software and hardware engineers, including those who have no experience of ARM products. Note: The information in this section is reproduced from source material provided to Atmel by ARM Ltd. in terms of Atmel’s license for the ARM Cortex-M3 processor core. This information is copyright ARM Ltd., 2008 - 2009. 12.2 About the Cortex-M3 processor and core peripherals  The Cortex-M3 processor is a high performance 32-bit processor designed for the microcontroller market. It offers significant benefits to developers, including:  outstanding processing performance combined with fast interrupt handling  enhanced system debug with extensive breakpoint and trace capabilities  efficient processor core, system and memories  ultra-low power consumption with integrated sleep modes  platform security, with integrated memory protection unit (MPU). Figure 12-1. Typical Cortex-M3 implementation Cortex-M3 Processor NVIC Debug Access Port Processor Core Memory Protection Unit Flash Patch Serial Wire Viewer Data Watchpoints Bus Matrix Code Interface SRAM and Peripheral Interface The Cortex-M3 processor is built on a high-performance processor core, with a 3-stage pipeline Harvard architecture, making it ideal for demanding embedded applications. The processor delivers exceptional power efficiency through an efficient instruction set and extensively optimized design, providing high-end processing hardware including single-cycle 32x32 multiplication and dedicated hardware division. To facilitate the design of cost-sensitive devices, the Cortex-M3 processor implements tightly-coupled system components that reduce processor area while significantly improving interrupt handling and system debug 44 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 capabilities. The Cortex-M3 processor implements a version of the Thumb® instruction set, ensuring high code density and reduced program memory requirements. The Cortex-M3 instruction set provides the exceptional performance expected of a modern 32-bit architecture, with the high code density of 8-bit and 16-bit microcontrollers. The Cortex-M3 processor closely integrates a configurable nested interrupt controller (NVIC), to deliver industryleading interrupt performance. The NVIC provides up to 16 interrupt priority levels. The tight integration of the processor core and NVIC provides fast execution of interrupt service routines (ISRs), dramatically reducing the interrupt latency. This is achieved through the hardware stacking of registers, and the ability to suspend loadmultiple and store-multiple operations. Interrupt handlers do not require any assembler stubs, removing any code overhead from the ISRs. Tail-chaining optimization also significantly reduces the overhead when switching from one ISR to another. To optimize low-power designs, the NVIC integrates with the sleep modes, that include a deep sleep function that enables the entire device to be rapidly powered down. 12.2.1 System level interface The Cortex-M3 processor provides multiple interfaces using AMBA® technology to provide high speed, low latency memory accesses. It supports unaligned data accesses and implements atomic bit manipulation that enables faster peripheral controls, system spinlocks and thread-safe Boolean data handling. The Cortex-M3 processor has a memory protection unit (MPU) that provides fine grain memory control, enabling applications to implement security privilege levels, separating code, data and stack on a task-by-task basis. Such requirements are becoming critical in many embedded applications. 12.2.2 Integrated configurable debug The Cortex-M3 processor implements a complete hardware debug solution. This provides high system visibility of the processor and memory through either a traditional JTAG port or a 2-pin Serial Wire Debug (SWD) port that is ideal for microcontrollers and other small package devices. For system trace the processor integrates an Instrumentation Trace Macrocell (ITM) alongside data watchpoints and a profiling unit. To enable simple and cost-effective profiling of the system events these generate, a Serial Wire Viewer (SWV) can export a stream of software-generated messages, data trace, and profiling information through a single pin. 12.2.3 Cortex-M3 processor features and benefits summary  tight integration of system peripherals reduces area and development costs  Thumb instruction set combines high code density with 32-bit performance  code-patch ability for ROM system updates  power control optimization of system components  integrated sleep modes for low power consumption  fast code execution permits slower processor clock or increases sleep mode time  hardware division and fast multiplier  deterministic, high-performance interrupt handling for time-critical applications • memory protection unit (MPU) for safety-critical applications  extensive debug and trace capabilities: ̶ Serial Wire Debug and Serial Wire Trace reduce the number of pins required for debugging and tracing. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 45 12.2.4 Cortex-M3 core peripherals These are: 12.2.4.1 Nested Vectored Interrupt Controller The Nested Vectored Interrupt Controller (NVIC) is an embedded interrupt controller that supports low latency interrupt processing. 12.2.4.2 System control block The System control block (SCB) is the programmers model interface to the processor. It provides system implementation information and system control, including configuration, control, and reporting of system exceptions. 12.2.4.3 System timer The system timer, SysTick, is a 24-bit count-down timer. Use this as a Real Time Operating System (RTOS) tick timer or as a simple counter. 12.2.4.4 Memory protection unit The Memory protection unit (MPU) improves system reliability by defining the memory attributes for different memory regions. It provides up to eight different regions, and an optional predefined background region. 12.3 Programmers model This section describes the Cortex-M3 programmers model. In addition to the individual core register descriptions, it contains information about the processor modes and privilege levels for software execution and stacks. 12.3.1 Processor mode and privilege levels for software execution The processor modes are: 12.3.1.1 Thread mode Used to execute application software. The processor enters Thread mode when it comes out of reset. 12.3.1.2 Handler mode Used to handle exceptions. The processor returns to Thread mode when it has finished exception processing. The privilege levels for software execution are: 12.3.1.3 Unprivileged The software:  has limited access to the MSR and MRS instructions, and cannot use the CPS instruction  cannot access the system timer, NVIC, or system control block  might have restricted access to memory or peripherals. Unprivileged software executes at the unprivileged level. 12.3.1.4 Privileged The software can use all the instructions and has access to all resources. Privileged software executes at the privileged level. In Thread mode, the CONTROL register controls whether software execution is privileged or unprivileged, see “CONTROL register” on page 56. In Handler mode, software execution is always privileged. Only privileged software can write to the CONTROL register to change the privilege level for software execution in Thread mode. Unprivileged software can use the SVC instruction to make a supervisor call to transfer control to privileged software. 46 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.3.2 Stacks The processor uses a full descending stack. This means the stack pointer indicates the last stacked item on the stack memory. When the processor pushes a new item onto the stack, it decrements the stack pointer and then writes the item to the new memory location. The processor implements two stacks, the main stack and the process stack, with independent copies of the stack pointer, see “Stack Pointer” on page 48. In Thread mode, the CONTROL register controls whether the processor uses the main stack or the process stack, see “CONTROL register” on page 56. In Handler mode, the processor always uses the main stack. The options for processor operations are: Table 12-1. Summary of processor mode, execution privilege level, and stack use options Processor mode Used to execute Privilege level for software execution Stack used Thread Applications Privileged or unprivileged (1) Main stack or process stack(1) Handler Exception handlers Always privileged Main stack 1. See “CONTROL register” on page 56. 12.3.3 Core registers The processor core registers are: 5 5 5 /RZUHJLVWHUV 5 5 5 5 *HQHUDOSXUSRVHUHJLVWHUV 5 5 5 +LJKUHJLVWHUV 5 5 5 6WDFN3RLQWHU 635 /LQN5HJLVWHU /55 3URJUDP&RXQWHU 3&5 365 363Á 063Á Á %DQNHGYHUVLRQRI63 3URJUDPVWDWXVUHJLVWHU 35,0$6. )$8/70$6. ([FHSWLRQPDVNUHJLVWHUV 6SHFLDOUHJLVWHUV %$6(35, &21752/ &21752/UHJLVWHU SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 47 Table 12-2. Core register set summary Name Type (1) Required privilege (2) Reset value Description R0-R12 RW Either Unknown “General-purpose registers” on page 48 MSP RW Privileged See description “Stack Pointer” on page 48 PSP RW Either Unknown “Stack Pointer” on page 48 LR RW Either 0xFFFFFFFF “Link Register” on page 48 PC RW Either See description “Program Counter” on page 48 PSR RW Privileged 0x01000000 “Program Status Register” on page 49 ASPR RW Either 0x00000000 “Application Program Status Register” on page 50 IPSR RO Privileged 0x00000000 “Interrupt Program Status Register” on page 51 EPSR RO Privileged 0x01000000 “Execution Program Status Register” on page 52 PRIMASK RW Privileged 0x00000000 “Priority Mask Register” on page 53 FAULTMASK RW Privileged 0x00000000 “Fault Mask Register” on page 54 BASEPRI RW Privileged 0x00000000 “Base Priority Mask Register” on page 55 CONTROL RW Privileged 0x00000000 “CONTROL register” on page 56 1. 2. Describes access type during program execution in thread mode and Handler mode. Debug access can differ. An entry of Either means privileged and unprivileged software can access the register. 12.3.3.1 General-purpose registers R0-R12 are 32-bit general-purpose registers for data operations. 12.3.3.2 Stack Pointer The Stack Pointer (SP) is register R13. In Thread mode, bit[1] of the CONTROL register indicates the stack pointer to use:  0 = Main Stack Pointer (MSP). This is the reset value.  1 = Process Stack Pointer (PSP). On reset, the processor loads the MSP with the value from address 0x00000000. 12.3.3.3 Link Register The Link Register (LR) is register R14. It stores the return information for subroutines, function calls, and exceptions. On reset, the processor loads the LR value 0xFFFFFFFF. 12.3.3.4 Program Counter The Program Counter (PC) is register R15. It contains the current program address. Bit[0] is always 0 because instruction fetches must be halfword aligned. On reset, the processor loads the PC with the value of the reset vector, which is at address 0x00000004. 48 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.3.3.5 Program Status Register The Program Status Register (PSR) combines:  Application Program Status Register (APSR)  Interrupt Program Status Register (IPSR)  Execution Program Status Register (EPSR). These registers are mutually exclusive bitfields in the 32-bit PSR. The bit assignments are: • APSR: 31 30 29 28 27 N Z C V Q 23 22 21 20 26 25 24 Reserved 19 18 17 16 11 10 9 8 3 2 1 0 27 26 25 24 19 18 17 16 11 10 9 Reserved 15 14 13 12 Reserved 7 6 5 4 Reserved • IPSR: 31 30 29 28 Reserved 23 22 21 20 Reserved 15 14 13 12 7 6 5 8 ISR_NUMBER Reserved 4 3 2 27 26 1 0 25 24 ISR_NUMBER • EPSR: 31 30 29 28 Reserved 23 22 ICI/IT 21 20 T 19 18 17 11 10 9 16 Reserved 15 14 13 12 ICI/IT 7 6 5 8 Reserved 4 3 2 1 0 Reserved SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 49 The PSR bit assignments are: 31 30 29 28 27 N Z C V Q 23 22 21 20 26 25 ICI/IT 24 T 19 18 17 16 11 10 9 8 Reserved ISR_NUMBER 1 0 Reserved 15 14 13 12 ICI/IT 7 6 5 4 3 2 ISR_NUMBER Access these registers individually or as a combination of any two or all three registers, using the register name as an argument to the MSR or MRS instructions. For example:  read all of the registers using PSR with the MRS instruction  write to the APSR using APSR with the MSR instruction. The PSR combinations and attributes are: Table 12-3. PSR register combinations Register Type PSR RW (1), IEPSR RO IAPSR (2) APSR, EPSR, and IPSR EPSR and IPSR (1) APSR and IPSR (2) APSR and EPSR RW EAPSR 1. 2. Combination RW The processor ignores writes to the IPSR bits. Reads of the EPSR bits return zero, and the processor ignores writes to the these bits. See the instruction descriptions “MRS” on page 141 and “MSR” on page 142 for more information about how to access the program status registers. 12.3.3.6 Application Program Status Register The APSR contains the current state of the condition flags from previous instruction executions. See the register summary in Table 12-2 on page 48 for its attributes. The bit assignments are: • N Negative or less than flag: 0 = operation result was positive, zero, greater than, or equal 1 = operation result was negative or less than. • Z Zero flag: 0 = operation result was not zero 1 = operation result was zero. 50 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • C Carry or borrow flag: 0 = add operation did not result in a carry bit or subtract operation resulted in a borrow bit 1 = add operation resulted in a carry bit or subtract operation did not result in a borrow bit. • V Overflow flag: 0 = operation did not result in an overflow 1 = operation resulted in an overflow. • Q Sticky saturation flag: 0 = indicates that saturation has not occurred since reset or since the bit was last cleared to zero 1 = indicates when an SSAT or USAT instruction results in saturation. This bit is cleared to zero by software using an MRS instruction. 12.3.3.7 Interrupt Program Status Register The IPSR contains the exception type number of the current Interrupt Service Routine (ISR). See the register summary in Table 12-2 on page 48 for its attributes. The bit assignments are: • ISR_NUMBER This is the number of the current exception: 0 = Thread mode 1 = Reserved 2 = NMI 3 = Hard fault 4 = Memory management fault 5 = Bus fault 6 = Usage fault 7-10 = Reserved 11 = SVCall 12 = Reserved for Debug 13 = Reserved 14 = PendSV 15 = SysTick 16 = IRQ0 45 = IRQ29 see “Exception types” on page 67 for more information. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 51 12.3.3.8 Execution Program Status Register The EPSR contains the Thumb state bit, and the execution state bits for either the:  If-Then (IT) instruction  Interruptible-Continuable Instruction (ICI) field for an interrupted load multiple or store multiple instruction. See the register summary in Table 12-2 on page 48 for the EPSR attributes. The bit assignments are: • ICI Interruptible-continuable instruction bits, see “Interruptible-continuable instructions” on page 52. • IT Indicates the execution state bits of the IT instruction, see “IT” on page 132. • T Always set to 1. Attempts to read the EPSR directly through application software using the MSR instruction always return zero. Attempts to write the EPSR using the MSR instruction in application software are ignored. Fault handlers can examine EPSR value in the stacked PSR to indicate the operation that is at fault. See “Exception entry and return” on page 71 12.3.3.9 Interruptible-continuable instructions When an interrupt occurs during the execution of an LDM or STM instruction, the processor:  stops the load multiple or store multiple instruction operation temporarily  stores the next register operand in the multiple operation to EPSR bits[15:12]. After servicing the interrupt, the processor:  returns to the register pointed to by bits[15:12]  resumes execution of the multiple load or store instruction. When the EPSR holds ICI execution state, bits[26:25,11:10] are zero. 12.3.3.10 If-Then block The If-Then block contains up to four instructions following a 16-bit IT instruction. Each instruction in the block is conditional. The conditions for the instructions are either all the same, or some can be the inverse of others. See “IT” on page 132 for more information. 12.3.3.11 Exception mask registers The exception mask registers disable the handling of exceptions by the processor. Disable exceptions where they might impact on timing critical tasks. To access the exception mask registers use the MSR and MRS instructions, or the CPS instruction to change the value of PRIMASK or FAULTMASK. See “MRS” on page 141, “MSR” on page 142, and “CPS” on page 137 for more information. 52 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.3.3.12 Priority Mask Register The PRIMASK register prevents activation of all exceptions with configurable priority. See the register summary in Table 12-2 on page 48 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 4 Reserved 0 PRIMASK • PRIMASK 0 = no effect 1 = prevents the activation of all exceptions with configurable priority. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 53 12.3.3.13 Fault Mask Register The FAULTMASK register prevents activation of all exceptions. See the register summary in Table 12-2 on page 48 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 4 Reserved • FAULTMASK 0 = no effect 1 = prevents the activation of all exceptions. The processor clears the FAULTMASK bit to 0 on exit from any exception handler except the NMI handler. 54 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 0 FAULTMASK 12.3.3.14 Base Priority Mask Register The BASEPRI register defines the minimum priority for exception processing. When BASEPRI is set to a nonzero value, it prevents the activation of all exceptions with same or lower priority level as the BASEPRI value. See the register summary in Table 12-2 on page 48 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 4 BASEPRI • BASEPRI Priority mask bits: 0x0000 = no effect Nonzero = defines the base priority for exception processing. The processor does not process any exception with a priority value greater than or equal to BASEPRI. This field is similar to the priority fields in the interrupt priority registers. The processor implements only bits[7:4] of this field, bits[3:0] read as zero and ignore writes. See “Interrupt Priority Registers” on page 156 for more information. Remember that higher priority field values correspond to lower exception priorities. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 55 12.3.3.15 CONTROL register The CONTROL register controls the stack used and the privilege level for software execution when the processor is in Thread mode. See the register summary in Table 12-2 on page 48 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 4 Reserved 1 0 Active Stack Pointer Thread Mode Privilege Level • Active stack pointer Defines the current stack: 0 = MSP is the current stack pointer 1 = PSP is the current stack pointer. In Handler mode this bit reads as zero and ignores writes. • Thread mode privilege level Defines the Thread mode privilege level: 0 = privileged 1 = unprivileged. Handler mode always uses the MSP, so the processor ignores explicit writes to the active stack pointer bit of the CONTROL register when in Handler mode. The exception entry and return mechanisms update the CONTROL register. In an OS environment, ARM recommends that threads running in Thread mode use the process stack and the kernel and exception handlers use the main stack. By default, Thread mode uses the MSP. To switch the stack pointer used in Thread mode to the PSP, use the MSR instruction to set the Active stack pointer bit to 1, see “MSR” on page 142. When changing the stack pointer, software must use an ISB instruction immediately after the MSR instruction. This ensures that instructions after the ISB execute using the new stack pointer. See “ISB” on page 140 56 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.3.4 Exceptions and interrupts The Cortex-M3 processor supports interrupts and system exceptions. The processor and the Nested Vectored Interrupt Controller (NVIC) prioritize and handle all exceptions. An exception changes the normal flow of software control. The processor uses handler mode to handle all exceptions except for reset. See “Exception entry” on page 72 and “Exception return” on page 72 for more information. The NVIC registers control interrupt handling. See “Nested Vectored Interrupt Controller” on page 149 for more information. 12.3.5 Data types The processor:  supports the following data types: ̶ 32-bit words ̶ 16-bit halfwords ̶ 8-bit bytes  supports 64-bit data transfer instructions.  manages all data memory accesses as little-endian. Instruction memory and Private Peripheral Bus (PPB) accesses are always little-endian. See “Memory regions, types and attributes” on page 58 for more information. 12.3.6 The Cortex Microcontroller Software Interface Standard For a Cortex-M3 microcontroller system, the Cortex Microcontroller Software Interface Standard (CMSIS) defines:    a common way to: ̶ access peripheral registers ̶ define exception vectors the names of: ̶ the registers of the core peripherals ̶ the core exception vectors a device-independent interface for RTOS kernels, including a debug channel. The CMSIS includes address definitions and data structures for the core peripherals in the Cortex-M3 processor. It also includes optional interfaces for middleware components comprising a TCP/IP stack and a Flash file system. CMSIS simplifies software development by enabling the reuse of template code and the combination of CMSIScompliant software components from various middleware vendors. Software vendors can expand the CMSIS to include their peripheral definitions and access functions for those peripherals. This document includes the register names defined by the CMSIS, and gives short descriptions of the CMSIS functions that address the processor core and the core peripherals. This document uses the register short names defined by the CMSIS. In a few cases these differ from the architectural short names that might be used in other documents. The following sections give more information about the CMSIS:  “Power management programming hints” on page 77  “Intrinsic functions” on page 81  “The CMSIS mapping of the Cortex-M3 NVIC registers” on page 149  “NVIC programming hints” on page 159. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 57 12.4 Memory model This section describes the processor memory map, the behavior of memory accesses, and the bit-banding features. The processor has a fixed memory map that provides up to 4GB of addressable memory. The memory map is: [)))))))) 9HQGRUVSHFLILF PHPRU\ 0% [( [())))) 3ULYDWHSHULSKHUDO 0% EXV [( ['))))))) ([WHUQDOGHYLFH *% [$ [))))))) ([WHUQDO5$0 [)))))) *% 0% %LWEDQGDOLDV [ [))))))) [ [))))) 0% %LWEDQGUHJLRQ [ 3HULSKHUDO *% [ [))))))) [)))))) 0% %LWEDQGDOLDV 65$0 *% [ [))))))) [ [))))) 0% %LWEDQGUHJLRQ [ &RGH *% [ The regions for SRAM and peripherals include bit-band regions. Bit-banding provides atomic operations to bit data, see “Bit-banding” on page 62. The processor reserves regions of the Private peripheral bus (PPB) address range for core peripheral registers, see “About the Cortex-M3 peripherals” on page 148. This memory mapping is generic to ARM Cortex-M3 products. To get the specific memory mapping of this product, refer to the Memories section of the datasheet. 12.4.1 Memory regions, types and attributes The memory map and the programming of the MPU split the memory map into regions. Each region has a defined memory type, and some regions have additional memory attributes. The memory type and attributes determine the behavior of accesses to the region. 58 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 The memory types are: 12.4.1.1 Normal The processor can re-order transactions for efficiency, or perform speculative reads. 12.4.1.2 Device The processor preserves transaction order relative to other transactions to Device or Strongly-ordered memory. 12.4.1.3 Strongly-ordered The processor preserves transaction order relative to all other transactions. The different ordering requirements for Device and Strongly-ordered memory mean that the memory system can buffer a write to Device memory, but must not buffer a write to Strongly-ordered memory. The additional memory attributes include. 12.4.1.4 Shareable For a shareable memory region, the memory system provides data synchronization between bus masters in a system with multiple bus masters, for example, a processor with a DMA controller. Strongly-ordered memory is always shareable. If multiple bus masters can access a non-shareable memory region, software must ensure data coherency between the bus masters. 12.4.1.5 Execute Never (XN) Means the processor prevents instruction accesses. Any attempt to fetch an instruction from an XN region causes a memory management fault exception. 12.4.2 Memory system ordering of memory accesses For most memory accesses caused by explicit memory access instructions, the memory system does not guarantee that the order in which the accesses complete matches the program order of the instructions, providing this does not affect the behavior of the instruction sequence. Normally, if correct program execution depends on two memory accesses completing in program order, software must insert a memory barrier instruction between the memory access instructions, see “Software ordering of memory accesses” on page 61. However, the memory system does guarantee some ordering of accesses to Device and Strongly-ordered memory. For two memory access instructions A1 and A2, if A1 occurs before A2 in program order, the ordering of the memory accesses caused by two instructions is: 1RUPDO DFFHVV 1RQVKDUHDEOH 6KDUHDEOH 6WURQJO\ RUGHUHG DFFHVV 1RUPDODFFHVV     'HYLFHDFFHVVQRQVKDUHDEOH     'HYLFHDFFHVVVKDUHDEOH     6WURQJO\RUGHUHGDFFHVV     $ $ 'HYLFHDFFHVV Where: - Means that the memory system does not guarantee the ordering of the accesses. < Means that accesses are observed in program order, that is, A1 is always observed before A2. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 59 12.4.3 Behavior of memory accesses The behavior of accesses to each region in the memory map is: Table 12-4. Memory access behavior Address range Memory region Memory type XN Description 0x000000000x1FFFFFFF Code Normal (1) - Executable region for program code. You can also put data here. 0x200000000x3FFFFFFF SRAM Normal (1) - 0x400000000x5FFFFFFF Peripheral Device (1) XN This region includes bit band and bit band alias areas, see Table 12-6 on page 63. 0x600000000x9FFFFFFF External RAM Normal (1) - Executable region for data. 0xA00000000xDFFFFFFF External device Device (1) XN External Device memory 0xE00000000xE00FFFFF Private Peripheral Bus Strongly- ordered (1) XN This region includes the NVIC, System timer, and system control block. 0xE01000000xFFFFFFFF Reserved Device (1) XN Reserved 1. Executable region for data. You can also put code here. This region includes bit band and bit band alias areas, see Table 12-6 on page 63. See “Memory regions, types and attributes” on page 58 for more information. The Code, SRAM, and external RAM regions can hold programs. However, ARM recommends that programs always use the Code region. This is because the processor has separate buses that enable instruction fetches and data accesses to occur simultaneously. The MPU can override the default memory access behavior described in this section. For more information, see “Memory protection unit” on page 194. 60 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.4.3.1 Additional memory access constraints for shared memory When a system includes shared memory, some memory regions have additional access constraints, and some regions are subdivided, as Table 12-5 shows: Table 12-5. Memory region share ability policies Address range Memory region Memory type Shareability 0x000000000x1FFFFFFF Code Normal (1) - 0x200000000x3FFFFFFF SRAM Normal (1) - 0x400000000x5FFFFFFF Peripheral (2) Device (1) - 0x600000000x7FFFFFFF WBWA (2) External RAM Normal (1) - 0x800000000x9FFFFFFF WT (2) 0xA00000000xBFFFFFFF Shareable (1) External device Device (1) 0xC00000000xDFFFFFFF Non-shareable (1) 0xE00000000xE00FFFFF Private Peripheral Bus Strongly- ordered(1) Shareable (1) - 0xE01000000xFFFFFFFF Vendor-specific device(2) Device (1) - - 1. 2. See “Memory regions, types and attributes” on page 58 for more information. The Peripheral and Vendor-specific device regions have no additional access constraints. 12.4.4 Software ordering of memory accesses The order of instructions in the program flow does not always guarantee the order of the corresponding memory transactions. This is because:  the processor can reorder some memory accesses to improve efficiency, providing this does not affect the behavior of the instruction sequence.  the processor has multiple bus interfaces  memory or devices in the memory map have different wait states  some memory accesses are buffered or speculative. “Memory system ordering of memory accesses” on page 59 describes the cases where the memory system guarantees the order of memory accesses. Otherwise, if the order of memory accesses is critical, software must include memory barrier instructions to force that ordering. The processor provides the following memory barrier instructions: 12.4.4.1 DMB The Data Memory Barrier (DMB) instruction ensures that outstanding memory transactions complete before subsequent memory transactions. See “DMB” on page 138. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 61 12.4.4.2 DSB The Data Synchronization Barrier (DSB) instruction ensures that outstanding memory transactions complete before subsequent instructions execute. See “DSB” on page 139. 12.4.4.3 ISB The Instruction Synchronization Barrier (ISB) ensures that the effect of all completed memory transactions is recognizable by subsequent instructions. See “ISB” on page 140. Use memory barrier instructions in, for example:  MPU programming: ̶ Use a DSB instruction to ensure the effect of the MPU takes place immediately at the end of context switching. ̶ Use an ISB instruction to ensure the new MPU setting takes effect immediately after programming the MPU region or regions, if the MPU configuration code was accessed using a branch or call. If the MPU configuration code is entered using exception mechanisms, then an ISB instruction is not required.  Vector table. If the program changes an entry in the vector table, and then enables the corresponding exception, use a DMB instruction between the operations. This ensures that if the exception is taken immediately after being enabled the processor uses the new exception vector.  Self-modifying code. If a program contains self-modifying code, use an ISB instruction immediately after the code modification in the program. This ensures subsequent instruction execution uses the updated program.  Memory map switching. If the system contains a memory map switching mechanism, use a DSB instruction after switching the memory map in the program. This ensures subsequent instruction execution uses the updated memory map.  Dynamic exception priority change. When an exception priority has to change when the exception is pending or active, use DSB instructions after the change. This ensures the change takes effect on completion of the DSB instruction.  Using a semaphore in multi-master system. If the system contains more than one bus master, for example, if another processor is present in the system, each processor must use a DMB instruction after any semaphore instructions, to ensure other bus masters see the memory transactions in the order in which they were executed. Memory accesses to Strongly-ordered memory, such as the system control block, do not require the use of DMB instructions. 12.4.5 Bit-banding A bit-band region maps each word in a bit-band alias region to a single bit in the bit-band region. The bit-band regions occupy the lowest 1MB of the SRAM and peripheral memory regions. The memory map has two 32MB alias regions that map to two 1MB bit-band regions: 62  accesses to the 32MB SRAM alias region map to the 1MB SRAM bit-band region, as shown in Table 12-6  accesses to the 32MB peripheral alias region map to the 1MB peripheral bit-band region, as shown in Table 12-7. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 12-6. SRAM memory bit-banding regions Address range Memory region 0x20000000- SRAM bit-band region Direct accesses to this memory range behave as SRAM memory accesses, but this region is also bit addressable through bit-band alias. SRAM bit-band alias Data accesses to this region are remapped to bit band region. A write operation is performed as read-modify-write. Instruction accesses are not remapped. 0x200FFFFF 0x220000000x23FFFFFF Table 12-7. Instruction and data accesses Peripheral memory bit-banding regions Address range Memory region 0x40000000- Peripheral bit-band alias Direct accesses to this memory range behave as peripheral memory accesses, but this region is also bit addressable through bit-band alias. Peripheral bit-band region Data accesses to this region are remapped to bit band region. A write operation is performed as read-modify-write. Instruction accesses are not permitted. 0x400FFFFF 0x420000000x43FFFFFF Instruction and data accesses A word access to the SRAM or peripheral bit-band alias regions map to a single bit in the SRAM or peripheral bitband region. The following formula shows how the alias region maps onto the bit-band region: bit_word_offset = (byte_offset x 32) + (bit_number x 4) bit_word_addr = bit_band_base + bit_word_offset where:  Bit_word_offset is the position of the target bit in the bit-band memory region.  Bit_word_addr is the address of the word in the alias memory region that maps to the targeted bit.  Bit_band_base is the starting address of the alias region.  Byte_offset is the number of the byte in the bit-band region that contains the targeted bit.  Bit_number is the bit position, 0-7, of the targeted bit. Figure 12-2 shows examples of bit-band mapping between the SRAM bit-band alias region and the SRAM bitband region:  The alias word at 0x23FFFFE0 maps to bit[0] of the bit-band byte at 0x200FFFFF: 0x23FFFFE0 = 0x22000000 + (0xFFFFF*32) + (0*4).  The alias word at 0x23FFFFFC maps to bit[7] of the bit-band byte at 0x200FFFFF: 0x23FFFFFC = 0x22000000 + (0xFFFFF*32) + (7*4).  The alias word at 0x22000000 maps to bit[0] of the bit-band byte at 0x20000000: 0x22000000 = 0x22000000 + (0*32) + (0 *4).  The alias word at 0x2200001C maps to bit[7] of the bit-band byte at 0x20000000: 0x2200001C = 0x22000000+ (0*32) + (7*4). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 63 Figure 12-2. Bit-band mapping 0%DOLDVUHJLRQ [)))))& [))))) [))))) [))))) [))))(& [))))( [))))( [))))( [& [ [ [ [& [ [ [ 0%65$0ELWEDQGUHJLRQ           [)))))               [))))(     [     [         [))))'         [         [))))&         [ 12.4.5.1 Directly accessing an alias region Writing to a word in the alias region updates a single bit in the bit-band region. Bit[0] of the value written to a word in the alias region determines the value written to the targeted bit in the bitband region. Writing a value with bit[0] set to 1 writes a 1 to the bit-band bit, and writing a value with bit[0] set to 0 writes a 0 to the bit-band bit. Bits[31:1] of the alias word have no effect on the bit-band bit. Writing 0x01 has the same effect as writing 0xFF. Writing 0x00 has the same effect as writing 0x0E. Reading a word in the alias region:  0x00000000 indicates that the targeted bit in the bit-band region is set to zero  0x00000001 indicates that the targeted bit in the bit-band region is set to 1 12.4.5.2 Directly accessing a bit-band region “Behavior of memory accesses” on page 60 describes the behavior of direct byte, halfword, or word accesses to the bit-band regions. 12.4.6 Memory endianness The processor views memory as a linear collection of bytes numbered in ascending order from zero. For example, bytes 0-3 hold the first stored word, and bytes 4-7 hold the second stored word. or “Little-endian format” describes how words of data are stored in memory. 64 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.4.6.1 Little-endian format In little-endian format, the processor stores the least significant byte of a word at the lowest-numbered byte, and the most significant byte at the highest-numbered byte. For example: 0HPRU\  5HJLVWHU   $GGUHVV$ % $ % $ % $ % OVE\WH   %   %   %  % PVE\WH 12.4.7 Synchronization primitives The Cortex-M3 instruction set includes pairs of synchronization primitives. These provide a non-blocking mechanism that a thread or process can use to obtain exclusive access to a memory location. Software can use them to perform a guaranteed read-modify-write memory update sequence, or for a semaphore mechanism. A pair of synchronization primitives comprises: 12.4.7.1 A Load-Exclusive instruction Used to read the value of a memory location, requesting exclusive access to that location. 12.4.7.2 A Store-Exclusive instruction Used to attempt to write to the same memory location, returning a status bit to a register. If this bit is: 0: it indicates that the thread or process gained exclusive access to the memory, and the write succeeds, 1: it indicates that the thread or process did not gain exclusive access to the memory, and no write is performed, The pairs of Load-Exclusive and Store-Exclusive instructions are:  the word instructions LDREX and STREX  the halfword instructions LDREXH and STREXH  the byte instructions LDREXB and STREXB. Software must use a Load-Exclusive instruction with the corresponding Store-Exclusive instruction. To perform a guaranteed read-modify-write of a memory location, software must:  Use a Load-Exclusive instruction to read the value of the location.  Update the value, as required.  Use a Store-Exclusive instruction to attempt to write the new value back to the memory location, and tests the returned status bit. If this bit is: 0: The read-modify-write completed successfully, 1: No write was performed. This indicates that the value returned the first step might be out of date. The software must retry the read-modify-write sequence, Software can use the synchronization primitives to implement a semaphores as follows:  Use a Load-Exclusive instruction to read from the semaphore address to check whether the semaphore is free.  If the semaphore is free, use a Store-Exclusive to write the claim value to the semaphore address. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 65  If the returned status bit from the second step indicates that the Store-Exclusive succeeded then the software has claimed the semaphore. However, if the Store-Exclusive failed, another process might have claimed the semaphore after the software performed the first step. The Cortex-M3 includes an exclusive access monitor, that tags the fact that the processor has executed a LoadExclusive instruction. If the processor is part of a multiprocessor system, the system also globally tags the memory locations addressed by exclusive accesses by each processor. The processor removes its exclusive access tag if:  It executes a CLREX instruction  It executes a Store-Exclusive instruction, regardless of whether the write succeeds.  An exception occurs. This means the processor can resolve semaphore conflicts between different threads. In a multiprocessor implementation:  executing a CLREX instruction removes only the local exclusive access tag for the processor  executing a Store-Exclusive instruction, or an exception. removes the local exclusive access tags, and all global exclusive access tags for the processor. For more information about the synchronization primitive instructions, see “LDREX and STREX” on page 102 and “CLREX” on page 104. 12.4.8 Programming hints for the synchronization primitives ANSI C cannot directly generate the exclusive access instructions. Some C compilers provide intrinsic functions for generation of these instructions: Table 12-8. C compiler intrinsic functions for exclusive access instructions Instruction Intrinsic function LDREX, LDREXH, or LDREXB unsigned int __ldrex(volatile void *ptr) STREX, STREXH, or STREXB int __strex(unsigned int val, volatile void *ptr) CLREX void __clrex(void) The actual exclusive access instruction generated depends on the data type of the pointer passed to the intrinsic function. For example, the following C code generates the require LDREXB operation: __ldrex((volatile char *) 0xFF); 12.5 Exception model This section describes the exception model. 12.5.1 Exception states Each exception is in one of the following states: 12.5.1.1 Inactive The exception is not active and not pending. 12.5.1.2 Pending The exception is waiting to be serviced by the processor. An interrupt request from a peripheral or from software can change the state of the corresponding interrupt to pending. 66 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.5.1.3 Active An exception that is being serviced by the processor but has not completed. An exception handler can interrupt the execution of another exception handler. In this case both exceptions are in the active state. 12.5.1.4 Active and pending The exception is being serviced by the processor and there is a pending exception from the same source. 12.5.2 Exception types The exception types are: 12.5.2.1 Reset Reset is invoked on power up or a warm reset. The exception model treats reset as a special form of exception. When reset is asserted, the operation of the processor stops, potentially at any point in an instruction. When reset is deasserted, execution restarts from the address provided by the reset entry in the vector table. Execution restarts as privileged execution in Thread mode. 12.5.2.2 Non Maskable Interrupt (NMI) A non maskable interrupt (NMI) can be signalled by a peripheral or triggered by software. This is the highest priority exception other than reset. It is permanently enabled and has a fixed priority of -2. NMIs cannot be:   Masked or prevented from activation by any other exception. Preempted by any exception other than Reset. 12.5.2.3 Hard fault A hard fault is an exception that occurs because of an error during exception processing, or because an exception cannot be managed by any other exception mechanism. Hard faults have a fixed priority of -1, meaning they have higher priority than any exception with configurable priority. 12.5.2.4 Memory management fault A memory management fault is an exception that occurs because of a memory protection related fault. The MPU or the fixed memory protection constraints determines this fault, for both instruction and data memory transactions. This fault is used to abort instruction accesses to Execute Never (XN) memory regions, even if the MPU is disabled. 12.5.2.5 Bus fault A bus fault is an exception that occurs because of a memory related fault for an instruction or data memory transaction. This might be from an error detected on a bus in the memory system. 12.5.2.6 Usage fault A usage fault is an exception that occurs because of a fault related to instruction execution. This includes:  an undefined instruction  an illegal unaligned access  invalid state on instruction execution  an error on exception return. The following can cause a usage fault when the core is configured to report them:  an unaligned address on word and halfword memory access  division by zero. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 67 12.5.2.7 SVCall A supervisor call (SVC) is an exception that is triggered by the SVC instruction. In an OS environment, applications can use SVC instructions to access OS kernel functions and device drivers. 12.5.2.8 PendSV PendSV is an interrupt-driven request for system-level service. In an OS environment, use PendSV for context switching when no other exception is active. 12.5.2.9 SysTick A SysTick exception is an exception the system timer generates when it reaches zero. Software can also generate a SysTick exception. In an OS environment, the processor can use this exception as system tick. 12.5.2.10 Interrupt (IRQ) A interrupt, or IRQ, is an exception signalled by a peripheral, or generated by a software request. All interrupts are asynchronous to instruction execution. In the system, peripherals use interrupts to communicate with the processor. Table 12-9. Properties of the different exception types Exception number (1) IRQ number (1) Exception type Priority Vector address or offset (2) Activation 1 - Reset -3, the highest 0x00000004 Asynchronous 2 -14 NMI -2 0x00000008 Asynchronous 3 -13 Hard fault -1 0x0000000C - 4 -12 Memory management fault Configurable (3) 0x00000010 Synchronous 5 -11 Bus fault Configurable (3) 0x00000014 Synchronous when precise, asynchronous when imprecise 6 -10 Usage fault Configurable (3) 0x00000018 Synchronous 7-10 - - - Reserved - 0x0000002C Synchronous Reserved - 0x00000038 Asynchronous 11 -5 SVCall Configurable 12-13 - - - (3) (3) 14 -2 PendSV Configurable 15 -1 SysTick Configurable (3) 0x0000003C Asynchronous 16 and above 0 and above (4) Interrupt (IRQ) Configurable (5) 0x00000040 and above (6) Asynchronous 1. 2. 3. 4. 5. 6. To simplify the software layer, the CMSIS only uses IRQ numbers and therefore uses negative values for exceptions other than interrupts. The IPSR returns the Exception number, see “Interrupt Program Status Register” on page 51. See “Vector table” on page 70 for more information. See “System Handler Priority Registers” on page 173. See the “Peripheral Identifiers” section of the datasheet. See “Interrupt Priority Registers” on page 156. Increasing in steps of 4. For an asynchronous exception, other than reset, the processor can execute another instruction between when the exception is triggered and when the processor enters the exception handler. 68 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Privileged software can disable the exceptions that Table 12-9 on page 68 shows as having configurable priority, see:  “System Handler Control and State Register” on page 177  “Interrupt Clear-enable Registers” on page 152. For more information about hard faults, memory management faults, bus faults, and usage faults, see “Fault handling” on page 73. 12.5.3 Exception handlers The processor handles exceptions using: 12.5.3.1 Interrupt Service Routines (ISRs) Interrupts IRQ0 to IRQ29 are the exceptions handled by ISRs. 12.5.3.2 Fault handlers Hard fault, memory management fault, usage fault, bus fault are fault exceptions handled by the fault handlers. 12.5.3.3 System handlers NMI, PendSV, SVCall SysTick, and the fault exceptions are all system exceptions that are handled by system handlers. 12.5.4 Vector table The vector table contains the reset value of the stack pointer, and the start addresses, also called exception vectors, for all exception handlers. Figure 12-3 on page 70 shows the order of the exception vectors in the vector table. The least-significant bit of each vector must be 1, indicating that the exception handler is Thumb code. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 69 Figure 12-3. Vector table Exception number IRQ number 45 29 . . . 18 2 17 1 16 0 15 -1 14 -2 13 Vector Offset IRQ29 0x00B4 . . . 0x004C . . . IRQ2 0x0048 IRQ1 0x0044 IRQ0 0x0040 0x003C 0x0038 12 Systick PendSV Reserved Reserved for Debug 11 -5 10 SVCall 0x002C 9 Reserved 8 7 6 -10 5 -11 4 -12 3 -13 2 -14 1 0x0018 0x0014 0x0010 0x000C 0x0008 0x0004 0x0000 Usage fault Bus fault Memory management fault Hard fault Reserved Reset Initial SP value On system reset, the vector table is fixed at address 0x00000000. Privileged software can write to the VTOR to relocate the vector table start address to a different memory location, in the range 0x00000080 to 0x3FFFFF80, see “Vector Table Offset Register” on page 167. 12.5.5 Exception priorities As Table 12-9 on page 68 shows, all exceptions have an associated priority, with:  a lower priority value indicating a higher priority  configurable priorities for all exceptions except Reset, Hard fault. If software does not configure any priorities, then all exceptions with a configurable priority have a priority of 0. For information about configuring exception priorities see  “System Handler Priority Registers” on page 173  “Interrupt Priority Registers” on page 156. Configurable priority values are in the range 0-15. This means that the Reset, Hard fault, and NMI exceptions, with fixed negative priority values, always have higher priority than any other exception. For example, assigning a higher priority value to IRQ[0] and a lower priority value to IRQ[1] means that IRQ[1] has higher priority than IRQ[0]. If both IRQ[1] and IRQ[0] are asserted, IRQ[1] is processed before IRQ[0]. If multiple pending exceptions have the same priority, the pending exception with the lowest exception number takes precedence. For example, if both IRQ[0] and IRQ[1] are pending and have the same priority, then IRQ[0] is processed before IRQ[1]. 70 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 When the processor is executing an exception handler, the exception handler is preempted if a higher priority exception occurs. If an exception occurs with the same priority as the exception being handled, the handler is not preempted, irrespective of the exception number. However, the status of the new interrupt changes to pending. 12.5.6 Interrupt priority grouping To increase priority control in systems with interrupts, the NVIC supports priority grouping. This divides each interrupt priority register entry into two fields:  an upper field that defines the group priority  a lower field that defines a subpriority within the group. Only the group priority determines preemption of interrupt exceptions. When the processor is executing an interrupt exception handler, another interrupt with the same group priority as the interrupt being handled does not preempt the handler, If multiple pending interrupts have the same group priority, the subpriority field determines the order in which they are processed. If multiple pending interrupts have the same group priority and subpriority, the interrupt with the lowest IRQ number is processed first. For information about splitting the interrupt priority fields into group priority and subpriority, see “Application Interrupt and Reset Control Register” on page 168. 12.5.7 Exception entry and return Descriptions of exception handling use the following terms: 12.5.7.1 Preemption When the processor is executing an exception handler, an exception can preempt the exception handler if its priority is higher than the priority of the exception being handled. See “Interrupt priority grouping” on page 71 for more information about preemption by an interrupt. When one exception preempts another, the exceptions are called nested exceptions. See “Exception entry” on page 72 more information. 12.5.7.2 Return This occurs when the exception handler is completed, and:  there is no pending exception with sufficient priority to be serviced  the completed exception handler was not handling a late-arriving exception. The processor pops the stack and restores the processor state to the state it had before the interrupt occurred. See “Exception return” on page 72 for more information. 12.5.7.3 Tail-chaining This mechanism speeds up exception servicing. On completion of an exception handler, if there is a pending exception that meets the requirements for exception entry, the stack pop is skipped and control transfers to the new exception handler. 12.5.7.4 Late-arriving This mechanism speeds up preemption. If a higher priority exception occurs during state saving for a previous exception, the processor switches to handle the higher priority exception and initiates the vector fetch for that exception. State saving is not affected by late arrival because the state saved is the same for both exceptions. Therefore the state saving continues uninterrupted. The processor can accept a late arriving exception until the first instruction of the exception handler of the original exception enters the execute stage of the processor. On return from the exception handler of the late-arriving exception, the normal tail-chaining rules apply. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 71 12.5.7.5 Exception entry Exception entry occurs when there is a pending exception with sufficient priority and either:  the processor is in Thread mode  the new exception is of higher priority than the exception being handled, in which case the new exception preempts the original exception. When one exception preempts another, the exceptions are nested. Sufficient priority means the exception has more priority than any limits set by the mask registers, see “Exception mask registers” on page 52. An exception with less priority than this is pending but is not handled by the processor. When the processor takes an exception, unless the exception is a tail-chained or a late-arriving exception, the processor pushes information onto the current stack. This operation is referred as stacking and the structure of eight data words is referred as stack frame. The stack frame contains the following information:  R0-R3, R12  Return address  PSR  LR. Immediately after stacking, the stack pointer indicates the lowest address in the stack frame. Unless stack alignment is disabled, the stack frame is aligned to a double-word address. If the STKALIGN bit of the Configuration Control Register (CCR) is set to 1, stack align adjustment is performed during stacking. The stack frame includes the return address. This is the address of the next instruction in the interrupted program. This value is restored to the PC at exception return so that the interrupted program resumes. In parallel to the stacking operation, the processor performs a vector fetch that reads the exception handler start address from the vector table. When stacking is complete, the processor starts executing the exception handler. At the same time, the processor writes an EXC_RETURN value to the LR. This indicates which stack pointer corresponds to the stack frame and what operation mode the was processor was in before the entry occurred. If no higher priority exception occurs during exception entry, the processor starts executing the exception handler and automatically changes the status of the corresponding pending interrupt to active. If another higher priority exception occurs during exception entry, the processor starts executing the exception handler for this exception and does not change the pending status of the earlier exception. This is the late arrival case. 12.5.7.6 Exception return Exception return occurs when the processor is in Handler mode and executes one of the following instructions to load the EXC_RETURN value into the PC:  a POP instruction that includes the PC  a BX instruction with any register.  an LDR or LDM instruction with the PC as the destination. EXC_RETURN is the value loaded into the LR on exception entry. The exception mechanism relies on this value to detect when the processor has completed an exception handler. The lowest four bits of this value provide information on the return stack and processor mode. Table 12-10 shows the EXC_RETURN[3:0] values with a description of the exception return behavior. 72 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 The processor sets EXC_RETURN bits[31:4] to 0xFFFFFFF. When this value is loaded into the PC it indicates to the processor that the exception is complete, and the processor initiates the exception return sequence. Table 12-10. Exception return behavior EXC_RETURN[3:0] Description bXXX0 Reserved. Return to Handler mode. b0001 Exception return gets state from MSP. Execution uses MSP after return. b0011 Reserved. b01X1 Reserved. Return to Thread mode. b1001 Exception return gets state from MSP. Execution uses MSP after return. Return to Thread mode. b1101 Exception return gets state from PSP. Execution uses PSP after return. b1X11 12.6 Reserved. Fault handling Faults are a subset of the exceptions, see “Exception model” on page 66. The following generate a fault: ̶ a bus error on: ̶ an instruction fetch or vector table load ̶ a data access  an internally-detected error such as an undefined instruction or an attempt to change state with a BX instruction  attempting to execute an instruction from a memory region marked as Non-Executable (XN).  an MPU fault because of a privilege violation or an attempt to access an unmanaged region. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 73 12.6.1 Fault types Table 12-11 shows the types of fault, the handler used for the fault, the corresponding fault status register, and the register bit that indicates that the fault has occurred. See “Configurable Fault Status Register” on page 179 for more information about the fault status registers. Table 12-11. Faults Fault Handler Bus error on a vector read Bit name Fault status register VECTTBL Hard fault “Hard Fault Status Register” on page 185 Fault escalated to a hard fault FORCED MPU mismatch: - on instruction access on data access IACCVIOL Memory management fault (1) DACCVIOL during exception stacking MSTKERR during exception unstacking MUNSKERR Bus error: - during exception stacking “Memory Management Fault Address Register” on page 186 - STKERR during exception unstacking UNSTKERR Bus fault during instruction prefetch IBUSERR Precise data bus error PRECISERR Imprecise data bus error IMPRECISERR Attempt to access a coprocessor NOCP Undefined instruction UNDEFINSTR Attempt to enter an invalid instruction set state (2) INVSTATE Usage fault “Usage Fault Status Register” on page 183 Invalid EXC_RETURN value INVPC Illegal unaligned load or store UNALIGNED Divide By 0 DIVBYZERO 1. 2. 74 “Bus Fault Status Register” on page 181 Occurs on an access to an XN region even if the MPU is disabled. Attempting to use an instruction set other than the Thumb instruction set. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.6.2 Fault escalation and hard faults All faults exceptions except for hard fault have configurable exception priority, see “System Handler Priority Registers” on page 173. Software can disable execution of the handlers for these faults, see “System Handler Control and State Register” on page 177. Usually, the exception priority, together with the values of the exception mask registers, determines whether the processor enters the fault handler, and whether a fault handler can preempt another fault handler. as described in “Exception model” on page 66. In some situations, a fault with configurable priority is treated as a hard fault. This is called priority escalation, and the fault is described as escalated to hard fault. Escalation to hard fault occurs when:  A fault handler causes the same kind of fault as the one it is servicing. This escalation to hard fault occurs because a fault handler cannot preempt itself because it must have the same priority as the current priority level.  A fault handler causes a fault with the same or lower priority as the fault it is servicing. This is because the handler for the new fault cannot preempt the currently executing fault handler.  An exception handler causes a fault for which the priority is the same as or lower than the currently executing exception.  A fault occurs and the handler for that fault is not enabled. If a bus fault occurs during a stack push when entering a bus fault handler, the bus fault does not escalate to a hard fault. This means that if a corrupted stack causes a fault, the fault handler executes even though the stack push for the handler failed. The fault handler operates but the stack contents are corrupted. Only Reset and NMI can preempt the fixed priority hard fault. A hard fault can preempt any exception other than Reset, NMI, or another hard fault. 12.6.3 Fault status registers and fault address registers The fault status registers indicate the cause of a fault. For bus faults and memory management faults, the fault address register indicates the address accessed by the operation that caused the fault, as shown in Table 12-12. Table 12-12. Fault status and fault address registers Handler Status register name Address register name Register description Hard fault HFSR - “Hard Fault Status Register” on page 185 Memory management fault MMFSR MMFAR Bus fault BFSR BFAR Usage fault UFSR - “Memory Management Fault Status Register” on page 180 “Memory Management Fault Address Register” on page 186 “Bus Fault Status Register” on page 181 “Bus Fault Address Register” on page 187 “Usage Fault Status Register” on page 183 12.6.4 Lockup The processor enters a lockup state if a hard fault occurs when executing the hard fault handlers. When the processor is in lockup state it does not execute any instructions. The processor remains in lockup state until:  it is reset SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 75 12.7 Power management The Cortex-M3 processor sleep modes reduce power consumption:  Backup Mode  Wait Mode  Sleep Mode The SLEEPDEEP bit of the SCR selects which sleep mode is used, see “System Control Register” on page 170. For more information about the behavior of the sleep modes see “Low Power Modes” in the PMC section of the datasheet. This section describes the mechanisms for entering sleep mode, and the conditions for waking up from sleep mode. 12.7.1 Entering sleep mode This section describes the mechanisms software can use to put the processor into sleep mode. The system can generate spurious wakeup events, for example a debug operation wakes up the processor. Therefore software must be able to put the processor back into sleep mode after such an event. A program might have an idle loop to put the processor back to sleep mode. 12.7.1.1 Wait for interrupt The wait for interrupt instruction, WFI, causes immediate entry to sleep mode. When the processor executes a WFI instruction it stops executing instructions and enters sleep mode. See “WFI” on page 147 for more information. 12.7.1.2 Wait for event The wait for event instruction, WFE, causes entry to sleep mode conditional on the value of an one-bit event register. When the processor executes a WFE instruction, it checks this register:  if the register is 0 the processor stops executing instructions and enters sleep mode  if the register is 1 the processor clears the register to 0 and continues executing instructions without entering sleep mode. See “WFE” on page 146 for more information. 12.7.1.3 Sleep-on-exit If the SLEEPONEXIT bit of the SCR is set to 1, when the processor completes the execution of an exception handler it returns to Thread mode and immediately enters sleep mode. Use this mechanism in applications that only require the processor to run when an exception occurs. 12.7.2 Wakeup from sleep mode The conditions for the processor to wakeup depend on the mechanism that cause it to enter sleep mode. 12.7.2.1 Wakeup from WFI or sleep-on-exit Normally, the processor wakes up only when it detects an exception with sufficient priority to cause exception entry. Some embedded systems might have to execute system restore tasks after the processor wakes up, and before it executes an interrupt handler. To achieve this set the PRIMASK bit to 1 and the FAULTMASK bit to 0. If an interrupt arrives that is enabled and has a higher priority than current exception priority, the processor wakes up but does not execute the interrupt handler until the processor sets PRIMASK to zero. For more information about PRIMASK and FAULTMASK see “Exception mask registers” on page 52. 76 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.7.2.2 Wakeup from WFE The processor wakes up if:  it detects an exception with sufficient priority to cause exception entry In addition, if the SEVONPEND bit in the SCR is set to 1, any new pending interrupt triggers an event and wakes up the processor, even if the interrupt is disabled or has insufficient priority to cause exception entry. For more information about the SCR see “System Control Register” on page 170. 12.7.3 Power management programming hints ANSI C cannot directly generate the WFI and WFE instructions. The CMSIS provides the following intrinsic functions for these instructions: void __WFE(void) // Wait for Event void __WFE(void) // Wait for Interrupt SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 77 12.8 Instruction set summary The processor implements a version of the Thumb instruction set. Table 12-13 lists the supported instructions. In Table 12-13:  angle brackets, , enclose alternative forms of the operand  braces, {}, enclose optional operands  the Operands column is not exhaustive  Op2 is a flexible second operand that can be either a register or a constant  most instructions can use an optional condition code suffix. For more information on the instructions and operands, see the instruction descriptions. Table 12-13. 78 Cortex-M3 instructions Mnemonic Operands Brief description Flags ADC, ADCS {Rd,} Rn, Op2 Add with Carry N,Z,C,V page 106 ADD, ADDS {Rd,} Rn, Op2 Add N,Z,C,V page 106 ADD, ADDW {Rd,} Rn, #imm12 Add N,Z,C,V page 106 ADR Rd, label Load PC-relative address - page 91 AND, ANDS {Rd,} Rn, Op2 Logical AND N,Z,C page 108 ASR, ASRS Rd, Rm, Arithmetic Shift Right N,Z,C page 109 B label Branch - page 129 BFC Rd, #lsb, #width Bit Field Clear - page 125 BFI Rd, Rn, #lsb, #width Bit Field Insert - page 125 BIC, BICS {Rd,} Rn, Op2 Bit Clear N,Z,C page 108 BKPT #imm Breakpoint - page 136 BL label Branch with Link - page 129 BLX Rm Branch indirect with Link - page 129 BX Rm Branch indirect - page 129 CBNZ Rn, label Compare and Branch if Non Zero - page 131 CBZ Rn, label Compare and Branch if Zero - page 131 CLREX - Clear Exclusive - page 104 CLZ Rd, Rm Count leading zeros - page 111 CMN, CMNS Rn, Op2 Compare Negative N,Z,C,V page 112 CMP, CMPS Rn, Op2 Compare N,Z,C,V page 112 CPSID iflags Change Processor State, Disable Interrupts - page 137 CPSIE iflags Change Processor State, Enable Interrupts - page 137 DMB - Data Memory Barrier - page 138 DSB - Data Synchronization Barrier - page 139 EOR, EORS {Rd,} Rn, Op2 Exclusive OR N,Z,C page 108 ISB - Instruction Synchronization Barrier - page 140 IT - If-Then condition block - page 132 LDM Rn{!}, reglist Load Multiple registers, increment after - page 99 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Page Table 12-13. Cortex-M3 instructions (Continued) Mnemonic Operands Brief description Flags Page LDMDB, LDMEA Rn{!}, reglist Load Multiple registers, decrement before - page 99 LDMFD, LDMIA Rn{!}, reglist Load Multiple registers, increment after - page 99 LDR Rt, [Rn, #offset] Load Register with word - page 94 LDRB, LDRBT Rt, [Rn, #offset] Load Register with byte - page 94 LDRD Rt, Rt2, [Rn, #offset] Load Register with two bytes - page 94 LDREX Rt, [Rn, #offset] Load Register Exclusive - page 94 LDREXB Rt, [Rn] Load Register Exclusive with byte - page 94 LDREXH Rt, [Rn] Load Register Exclusive with halfword - page 94 LDRH, LDRHT Rt, [Rn, #offset] Load Register with halfword - page 94 LDRSB, LDRSBT Rt, [Rn, #offset] Load Register with signed byte - page 94 LDRSH, LDRSHT Rt, [Rn, #offset] Load Register with signed halfword - page 94 LDRT Rt, [Rn, #offset] Load Register with word - page 94 LSL, LSLS Rd, Rm, Logical Shift Left N,Z,C page 109 LSR, LSRS Rd, Rm, Logical Shift Right N,Z,C page 109 MLA Rd, Rn, Rm, Ra Multiply with Accumulate, 32-bit result - page 119 MLS Rd, Rn, Rm, Ra Multiply and Subtract, 32-bit result - page 119 MOV, MOVS Rd, Op2 Move N,Z,C page 113 MOVT Rd, #imm16 Move Top - page 115 MOVW, MOV Rd, #imm16 Move 16-bit constant N,Z,C page 113 MRS Rd, spec_reg Move from special register to general register - page 141 MSR spec_reg, Rm Move from general register to special register N,Z,C,V page 142 MUL, MULS {Rd,} Rn, Rm Multiply, 32-bit result N,Z page 119 MVN, MVNS Rd, Op2 Move NOT N,Z,C page 113 NOP - No Operation - page 143 ORN, ORNS {Rd,} Rn, Op2 Logical OR NOT N,Z,C page 108 ORR, ORRS {Rd,} Rn, Op2 Logical OR N,Z,C page 108 POP reglist Pop registers from stack - page 101 PUSH reglist Push registers onto stack - page 101 RBIT Rd, Rn Reverse Bits - page 116 REV Rd, Rn Reverse byte order in a word - page 116 REV16 Rd, Rn Reverse byte order in each halfword - page 116 REVSH Rd, Rn Reverse byte order in bottom halfword and sign extend - page 116 ROR, RORS Rd, Rm, Rotate Right N,Z,C page 109 RRX, RRXS Rd, Rm Rotate Right with Extend N,Z,C page 109 RSB, RSBS {Rd,} Rn, Op2 Reverse Subtract N,Z,C,V page 106 SBC, SBCS {Rd,} Rn, Op2 Subtract with Carry N,Z,C,V page 106 SBFX Rd, Rn, #lsb, #width Signed Bit Field Extract - SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 page 126 79 Table 12-13. 80 Cortex-M3 instructions (Continued) Mnemonic Operands Brief description Flags Page SDIV {Rd,} Rn, Rm Signed Divide - page 121 SEV - Send Event - page 144 SMLAL RdLo, RdHi, Rn, Rm Signed Multiply with Accumulate (32 x 32 + 64), 64-bit result - page 120 SMULL RdLo, RdHi, Rn, Rm Signed Multiply (32 x 32), 64-bit result - page 120 SSAT Rd, #n, Rm {,shift #s} Signed Saturate Q page 122 STM Rn{!}, reglist Store Multiple registers, increment after - page 99 STMDB, STMEA Rn{!}, reglist Store Multiple registers, decrement before - page 99 STMFD, STMIA Rn{!}, reglist Store Multiple registers, increment after - page 99 STR Rt, [Rn, #offset] Store Register word - page 94 STRB, STRBT Rt, [Rn, #offset] Store Register byte - page 94 STRD Rt, Rt2, [Rn, #offset] Store Register two words - page 94 STREX Rd, Rt, [Rn, #offset] Store Register Exclusive - page 102 STREXB Rd, Rt, [Rn] Store Register Exclusive byte - page 102 STREXH Rd, Rt, [Rn] Store Register Exclusive halfword - page 102 STRH, STRHT Rt, [Rn, #offset] Store Register halfword - page 94 STRT Rt, [Rn, #offset] Store Register word - page 94 SUB, SUBS {Rd,} Rn, Op2 Subtract N,Z,C,V page 106 SUB, SUBW {Rd,} Rn, #imm12 Subtract N,Z,C,V page 106 SVC #imm Supervisor Call - page 145 SXTB {Rd,} Rm {,ROR #n} Sign extend a byte - page 127 SXTH {Rd,} Rm {,ROR #n} Sign extend a halfword - page 127 TBB [Rn, Rm] Table Branch Byte - page 134 TBH [Rn, Rm, LSL #1] Table Branch Halfword - page 134 TEQ Rn, Op2 Test Equivalence N,Z,C page 117 TST Rn, Op2 Test N,Z,C page 117 UBFX Rd, Rn, #lsb, #width Unsigned Bit Field Extract - page 126 UDIV {Rd,} Rn, Rm Unsigned Divide - page 121 UMLAL RdLo, RdHi, Rn, Rm Unsigned Multiply with Accumulate (32 x 32 + 64), 64-bit result - page 120 UMULL RdLo, RdHi, Rn, Rm Unsigned Multiply (32 x 32), 64-bit result - page 120 USAT Rd, #n, Rm {,shift #s} Unsigned Saturate Q page 122 UXTB {Rd,} Rm {,ROR #n} Zero extend a byte - page 127 UXTH {Rd,} Rm {,ROR #n} Zero extend a halfword - page 127 WFE - Wait For Event - page 146 WFI - Wait For Interrupt - page 147 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.9 Intrinsic functions ANSI cannot directly access some Cortex-M3 instructions. This section describes intrinsic functions that can generate these instructions, provided by the CMIS and that might be provided by a C compiler. If a C compiler does not support an appropriate intrinsic function, you might have to use inline assembler to access some instructions. The CMSIS provides the following intrinsic functions to generate instructions that ANSI cannot directly access: Table 12-14. CMSIS intrinsic functions to generate some Cortex-M3 instructions Instruction CMSIS intrinsic function CPSIE I void __enable_irq(void) CPSID I void __disable_irq(void) CPSIE F void __enable_fault_irq(void) CPSID F void __disable_fault_irq(void) ISB void __ISB(void) DSB void __DSB(void) DMB void __DMB(void) REV uint32_t __REV(uint32_t int value) REV16 uint32_t __REV16(uint32_t int value) REVSH uint32_t __REVSH(uint32_t int value) RBIT uint32_t __RBIT(uint32_t int value) SEV void __SEV(void) WFE void __WFE(void) WFI void __WFI(void) The CMSIS also provides a number of functions for accessing the special registers using MRS and MSR instructions: Table 12-15. CMSIS intrinsic functions to access the special registers Special register Access CMSIS function Read uint32_t __get_PRIMASK (void) Write void __set_PRIMASK (uint32_t value) Read uint32_t __get_FAULTMASK (void) Write void __set_FAULTMASK (uint32_t value) Read uint32_t __get_BASEPRI (void) Write void __set_BASEPRI (uint32_t value) Read uint32_t __get_CONTROL (void) Write void __set_CONTROL (uint32_t value) Read uint32_t __get_MSP (void) Write void __set_MSP (uint32_t TopOfMainStack) Read uint32_t __get_PSP (void) Write void __set_PSP (uint32_t TopOfProcStack) PRIMASK FAULTMASK BASEPRI CONTROL MSP PSP SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 81 12.10 About the instruction descriptions The following sections give more information about using the instructions:  “Operands” on page 82  “Restrictions when using PC or SP” on page 82  “Flexible second operand” on page 82  “Shift Operations” on page 83  “Address alignment” on page 86  “PC-relative expressions” on page 86  “Conditional execution” on page 87  “Instruction width selection” on page 88. 12.10.1 Operands An instruction operand can be an ARM register, a constant, or another instruction-specific parameter. Instructions act on the operands and often store the result in a destination register. When there is a destination register in the instruction, it is usually specified before the operands. Operands in some instructions are flexible in that they can either be a register or a constant. See “Flexible second operand”. 12.10.2 Restrictions when using PC or SP Many instructions have restrictions on whether you can use the Program Counter (PC) or Stack Pointer (SP) for the operands or destination register. See instruction descriptions for more information. Bit[0] of any address you write to the PC with a BX, BLX, LDM, LDR, or POP instruction must be 1 for correct execution, because this bit indicates the required instruction set, and the Cortex-M3 processor only supports Thumb instructions. 12.10.3 Flexible second operand Many general data processing instructions have a flexible second operand. This is shown as Operand2 in the descriptions of the syntax of each instruction. Operand2 can be a:  “Constant”  “Register with optional shift” on page 83 12.10.3.1 Constant You specify an Operand2 constant in the form: #constant where constant can be:  any constant that can be produced by shifting an 8-bit value left by any number of bits within a 32-bit word  any constant of the form 0x00XY00XY  any constant of the form 0xXY00XY00  any constant of the form 0xXYXYXYXY. In the constants shown above, X and Y are hexadecimal digits. In addition, in a small number of instructions, constant can take a wider range of values. These are described in the individual instruction descriptions. 82 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 When an Operand2 constant is used with the instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to bit[31] of the constant, if the constant is greater than 255 and can be produced by shifting an 8-bit value. These instructions do not affect the carry flag if Operand2 is any other constant. 12.10.3.2 Instruction substitution Your assembler might be able to produce an equivalent instruction in cases where you specify a constant that is not permitted. For example, an assembler might assemble the instruction CMP Rd, #0xFFFFFFFE as the equivalent instruction CMN Rd, #0x2. 12.10.3.3 Register with optional shift You specify an Operand2 register in the form: Rm {, shift} where: Rm is the register holding the data for the second operand. shift is an optional shift to be applied to Rm. It can be one of: ASR #n arithmetic shift right n bits, 1 ≤ n ≤ 32. LSL #n logical shift left n bits, 1 ≤ n ≤ 31. LSR #n logical shift right n bits, 1 ≤ n ≤ 32. ROR #n rotate right n bits, 1 ≤ n ≤ 31. RRX rotate right one bit, with extend. - if omitted, no shift occurs, equivalent to LSL #0. If you omit the shift, or specify LSL #0, the instruction uses the value in Rm. If you specify a shift, the shift is applied to the value in Rm, and the resulting 32-bit value is used by the instruction. However, the contents in the register Rm remains unchanged. Specifying a register with shift also updates the carry flag when used with certain instructions. For information on the shift operations and how they affect the carry flag, see “Shift Operations” 12.10.4 Shift Operations Register shift operations move the bits in a register left or right by a specified number of bits, the shift length. Register shift can be performed:  directly by the instructions ASR, LSR, LSL, ROR, and RRX, and the result is written to a destination register  during the calculation of Operand2 by the instructions that specify the second operand as a register with shift, see “Flexible second operand” on page 82. The result is used by the instruction. The permitted shift lengths depend on the shift type and the instruction, see the individual instruction description or “Flexible second operand” on page 82. If the shift length is 0, no shift occurs. Register shift operations update the carry flag except when the specified shift length is 0. The following sub-sections describe the various shift operations and how they affect the carry flag. In these descriptions, Rm is the register containing the value to be shifted, and n is the shift length. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 83 12.10.4.1 ASR Arithmetic shift right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places, into the right-hand 32-n bits of the result. And it copies the original bit[31] of the register into the left-hand n bits of the result. See Figure 12-4 on page 84. You can use the ASR #n operation to divide the value in the register Rm by 2n, with the result being rounded towards negative-infinity. When the instruction is ASRS or when ASR #n is used in Operand2 with the instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[n-1], of the register Rm.  If n is 32 or more, then all the bits in the result are set to the value of bit[31] of Rm.  If n is 32 or more and the carry flag is updated, it is updated to the value of bit[31] of Rm. Figure 12-4. ASR #3 &DUU\ )ODJ         12.10.4.2 LSR Logical shift right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places, into the righthand 32-n bits of the result. And it sets the left-hand n bits of the result to 0. See Figure 12-5. You can use the LSR #n operation to divide the value in the register Rm by 2n, if the value is regarded as an unsigned integer. When the instruction is LSRS or when LSR #n is used in Operand2 with the instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[n-1], of the register Rm.  If n is 32 or more, then all the bits in the result are cleared to 0.  If n is 33 or more and the carry flag is updated, it is updated to 0. Figure 12-5. LSR #3   &DUU\ )ODJ          84 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.10.4.3 LSL Logical shift left by n bits moves the right-hand 32-n bits of the register Rm, to the left by n places, into the left-hand 32-n bits of the result. And it sets the right-hand n bits of the result to 0. See Figure 12-6 on page 85. You can use he LSL #n operation to multiply the value in the register Rm by 2n, if the value is regarded as an unsigned integer or a two’s complement signed integer. Overflow can occur without warning. When the instruction is LSLS or when LSL #n, with non-zero n, is used in Operand2 with the instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[32n], of the register Rm. These instructions do not affect the carry flag when used with LSL #0.  If n is 32 or more, then all the bits in the result are cleared to 0.  If n is 33 or more and the carry flag is updated, it is updated to 0. Figure 12-6. LSL #3           &DUU\ )ODJ  12.10.4.4 ROR Rotate right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places, into the right-hand 32-n bits of the result. And it moves the right-hand n bits of the register into the left-hand n bits of the result. See Figure 12-7. When the instruction is RORS or when ROR #n is used in Operand2 with the instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit rotation, bit[n-1], of the register Rm.  If n is 32, then the value of the result is same as the value in Rm, and if the carry flag is updated, it is updated to bit[31] of Rm.  ROR with shift length, n, more than 32 is the same as ROR with shift length n-32. Figure 12-7. ROR #3 &DUU\ )ODJ         SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 85 12.10.4.5 RRX Rotate right with extend moves the bits of the register Rm to the right by one bit. And it copies the carry flag into bit[31] of the result. See Figure 12-8 on page 86. When the instruction is RRXS or when RRX is used in Operand2 with the instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to bit[0] of the register Rm. Figure 12-8. RRX &DUU\ )ODJ       12.10.5 Address alignment An aligned access is an operation where a word-aligned address is used for a word, dual word, or multiple word access, or where a halfword-aligned address is used for a halfword access. Byte accesses are always aligned. The Cortex-M3 processor supports unaligned access only for the following instructions:  LDR, LDRT  LDRH, LDRHT  LDRSH, LDRSHT  STR, STRT  STRH, STRHT All other load and store instructions generate a usage fault exception if they perform an unaligned access, and therefore their accesses must be address aligned. For more information about usage faults see “Fault handling” on page 73. Unaligned accesses are usually slower than aligned accesses. In addition, some memory regions might not support unaligned accesses. Therefore, ARM recommends that programmers ensure that accesses are aligned. To avoid accidental generation of unaligned accesses, use the UNALIGN_TRP bit in the Configuration and Control Register to trap all unaligned accesses, see “Configuration and Control Register” on page 171. 12.10.6 PC-relative expressions A PC-relative expression or label is a symbol that represents the address of an instruction or literal data. It is represented in the instruction as the PC value plus or minus a numeric offset. The assembler calculates the required offset from the label and the address of the current instruction. If the offset is too big, the assembler produces an error. 86  For B, BL, CBNZ, and CBZ instructions, the value of the PC is the address of the current instruction plus 4 bytes.  For all other instructions that use labels, the value of the PC is the address of the current instruction plus 4 bytes, with bit[1] of the result cleared to 0 to make it word-aligned.  Your assembler might permit other syntaxes for PC-relative expressions, such as a label plus or minus a number, or an expression of the form [PC, #number]. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.10.7 Conditional execution Most data processing instructions can optionally update the condition flags in the Application Program Status Register (APSR) according to the result of the operation, see “Application Program Status Register” on page 50. Some instructions update all flags, and some only update a subset. If a flag is not updated, the original value is preserved. See the instruction descriptions for the flags they affect. You can execute an instruction conditionally, based on the condition flags set in another instruction, either:  immediately after the instruction that updated the flags  after any number of intervening instructions that have not updated the flags. Conditional execution is available by using conditional branches or by adding condition code suffixes to instructions. See Table 12-16 on page 88 for a list of the suffixes to add to instructions to make them conditional instructions. The condition code suffix enables the processor to test a condition based on the flags. If the condition test of a conditional instruction fails, the instruction:  does not execute  does not write any value to its destination register  does not affect any of the flags  does not generate any exception. Conditional instructions, except for conditional branches, must be inside an If-Then instruction block. See “IT” on page 132 for more information and restrictions when using the IT instruction. Depending on the vendor, the assembler might automatically insert an IT instruction if you have conditional instructions outside the IT block. Use the CBZ and CBNZ instructions to compare the value of a register against zero and branch on the result. This section describes:  “The condition flags”  “Condition code suffixes”. 12.10.7.1 The condition flags The APSR contains the following condition flags: N Set to 1 when the result of the operation was negative, cleared to 0 otherwise. Z Set to 1 when the result of the operation was zero, cleared to 0 otherwise. C Set to 1 when the operation resulted in a carry, cleared to 0 otherwise. V Set to 1 when the operation caused overflow, cleared to 0 otherwise. For more information about the APSR see “Program Status Register” on page 49. A carry occurs:  if the result of an addition is greater than or equal to 232  if the result of a subtraction is positive or zero  as the result of an inline barrel shifter operation in a move or logical instruction. Overflow occurs if the result of an add, subtract, or compare is greater than or equal to 231, or less than –231. Most instructions update the status flags only if the S suffix is specified. See the instruction descriptions for more information. 12.10.7.2 Condition code suffixes The instructions that can be conditional have an optional condition code, shown in syntax descriptions as {cond}. Conditional execution requires a preceding IT instruction. An instruction with a condition code is only executed if the condition code flags in the APSR meet the specified condition. Table 12-16 shows the condition codes to use. You can use conditional execution with the IT instruction to reduce the number of branch instructions in code. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 87 Table 12-16 also shows the relationship between condition code suffixes and the N, Z, C, and V flags. Table 12-16. Condition code suffixes Suffix Flags Meaning EQ Z=1 Equal NE Z=0 Not equal CS or HS C=1 Higher or same, unsigned ≥ CC or LO C=0 Lower, unsigned < MI N=1 Negative PL N=0 Positive or zero VS V=1 Overflow VC V=0 No overflow HI C = 1 and Z = 0 Higher, unsigned > LS C = 0 or Z = 1 Lower or same, unsigned ≤ GE N=V Greater than or equal, signed ≥ LT N != V Less than, signed < GT Z = 0 and N = V Greater than, signed > LE Z = 1 and N != V Less than or equal, signed ≤ AL Can have any value Always. This is the default when no suffix is specified. 12.10.7.3 Absolute value The example below shows the use of a conditional instruction to find the absolute value of a number. R0 = ABS(R1). MOVS IT RSBMI R0, R1 MI R0, R1, #0 ; R0 = R1, setting flags ; IT instruction for the negative condition ; If negative, R0 = -R1 12.10.7.4 Compare and update value The example below shows the use of conditional instructions to update the value of R4 if the signed values R0 is greater than R1 and R2 is greater than R3. CMP ITT CMPGT MOVGT R0, R1 GT R2, R3 R4, R5 ; ; ; ; Compare R0 and R1, setting flags IT instruction for the two GT conditions If 'greater than', compare R2 and R3, setting flags If still 'greater than', do R4 = R5 12.10.8 Instruction width selection There are many instructions that can generate either a 16-bit encoding or a 32-bit encoding depending on the operands and destination register specified. For some of these instructions, you can force a specific instruction size by using an instruction width suffix. The .W suffix forces a 32-bit instruction encoding. The .N suffix forces a 16-bit instruction encoding. If you specify an instruction width suffix and the assembler cannot generate an instruction encoding of the requested width, it generates an error. In some cases it might be necessary to specify the .W suffix, for example if the operand is the label of an instruction or literal data, as in the case of branch instructions. This is because the assembler might not automatically generate the right size encoding. 88 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.10.8.1 Instruction width selection To use an instruction width suffix, place it immediately after the instruction mnemonic and condition code, if any. The example below shows instructions with the instruction width suffix. BCS.W label ; creates a 32-bit instruction even for a short branch ADDS.W R0, R0, R1 ; creates a 32-bit instruction even though the same ; operation can be done by a 16-bit instruction SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 89 12.11 Memory access instructions Table 12-17 shows the memory access instructions: Table 12-17. 90 Memory access instructions Mnemonic Brief description See ADR Load PC-relative address “ADR” on page 91 CLREX Clear Exclusive “CLREX” on page 104 LDM{mode} Load Multiple registers “LDM and STM” on page 99 LDR{type} Load Register using immediate offset “LDR and STR, immediate offset” on page 92 LDR{type} Load Register using register offset “LDR and STR, register offset” on page 94 LDR{type}T Load Register with unprivileged access “LDR and STR, unprivileged” on page 96 LDR Load Register using PC-relative address “LDR, PC-relative” on page 97 LDREX{type} Load Register Exclusive “LDREX and STREX” on page 102 POP Pop registers from stack “PUSH and POP” on page 101 PUSH Push registers onto stack “PUSH and POP” on page 101 STM{mode} Store Multiple registers “LDM and STM” on page 99 STR{type} Store Register using immediate offset “LDR and STR, immediate offset” on page 92 STR{type} Store Register using register offset “LDR and STR, register offset” on page 94 STR{type}T Store Register with unprivileged access “LDR and STR, unprivileged” on page 96 STREX{type} Store Register Exclusive “LDREX and STREX” on page 102 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.11.1 ADR Load PC-relative address. 12.11.1.1 Syntax ADR{cond} Rd, label where: cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. label is a PC-relative expression. See “PC-relative expressions” on page 86. 12.11.1.2 Operation ADR determines the address by adding an immediate value to the PC, and writes the result to the destination register. ADR produces position-independent code, because the address is PC-relative. If you use ADR to generate a target address for a BX or BLX instruction, you must ensure that bit[0] of the address you generate is set to1 for correct execution. Values of label must be within the range of −4095 to +4095 from the address in the PC. You might have to use the .W suffix to get the maximum offset range or to generate addresses that are not wordaligned. See “Instruction width selection” on page 88. 12.11.1.3 Restrictions Rd must not be SP and must not be PC. 12.11.1.4 Condition flags This instruction does not change the flags. 12.11.1.5 Examples ADR R1, TextMessage ; Write address value of a location labelled as ; TextMessage to R1 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 91 12.11.2 LDR and STR, immediate offset Load and Store with immediate offset, pre-indexed immediate offset, or post-indexed immediate offset. 12.11.2.1 Syntax op{type}{cond} Rt, op{type}{cond} Rt, op{type}{cond} Rt, opD{cond} Rt, Rt2, opD{cond} Rt, Rt2, opD{cond} Rt, Rt2, [Rn {, #offset}] [Rn, #offset]! [Rn], #offset [Rn {, #offset}] [Rn, #offset]! [Rn], #offset ; ; ; ; ; ; immediate offset pre-indexed post-indexed immediate offset, two words pre-indexed, two words post-indexed, two words where: op is one of: LDR Load Register. STR Store Register. type is one of: B unsigned byte, zero extend to 32 bits on loads. SB signed byte, sign extend to 32 bits (LDR only). H unsigned halfword, zero extend to 32 bits on loads. SH signed halfword, sign extend to 32 bits (LDR only). - omit, for word. cond is an optional condition code, see “Conditional execution” on page 87. Rt is the register to load or store. Rn is the register on which the memory address is based. offset is an offset from Rn. If offset is omitted, the address is the contents of Rn. Rt2 is the additional register to load or store for two-word operations. 12.11.2.2 Operation LDR instructions load one or two registers with a value from memory. STR instructions store one or two register values to memory. Load and store instructions with immediate offset can use the following addressing modes: 12.11.2.3 Offset addressing The offset value is added to or subtracted from the address obtained from the register Rn. The result is used as the address for the memory access. The register Rn is unaltered. The assembly language syntax for this mode is: [Rn, #offset] 12.11.2.4 Pre-indexed addressing The offset value is added to or subtracted from the address obtained from the register Rn. The result is used as the address for the memory access and written back into the register Rn. The assembly language syntax for this mode is: [Rn, #offset]! 12.11.2.5 Post-indexed addressing The address obtained from the register Rn is used as the address for the memory access. The offset value is added to or subtracted from the address, and written back into the register Rn. The assembly language syntax for this mode is: [Rn], #offset 92 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 The value to load or store can be a byte, halfword, word, or two words. Bytes and halfwords can either be signed or unsigned. See “Address alignment” on page 86. Table 12-18 shows the ranges of offset for immediate, pre-indexed and post-indexed forms. Table 12-18. Offset ranges Instruction type Immediate offset Pre-indexed Post-indexed Word, halfword, signed halfword, byte, or signed byte −255 to 4095 −255 to 255 −255 to 255 Two words multiple of 4 in the range −1020 to 1020 multiple of 4 in the range −1020 to 1020 multiple of 4 in the range −1020 to 1020 12.11.2.6 Restrictions For load instructions:  Rt can be SP or PC for word loads only  Rt must be different from Rt2 for two-word loads  Rn must be different from Rt and Rt2 in the pre-indexed or post-indexed forms. When Rt is PC in a word load instruction:  bit[0] of the loaded value must be 1 for correct execution  a branch occurs to the address created by changing bit[0] of the loaded value to 0  if the instruction is conditional, it must be the last instruction in the IT block. For store instructions:  Rt can be SP for word stores only  Rt must not be PC  Rn must not be PC  Rn must be different from Rt and Rt2 in the pre-indexed or post-indexed forms. 12.11.2.7 Condition flags These instructions do not change the flags. 12.11.2.8 Examples LDR LDRNE R8, [R10] R2, [R5, #960]! STR R2, [R9,#const-struc] STRH R3, [R4], #4 LDRD R8, R9, [R3, #0x20] STRD R0, R1, [R8], #-16 ; ; ; ; ; ; ; ; ; ; ; ; ; ; Loads R8 from the address in R10. Loads (conditionally) R2 from a word 960 bytes above the address in R5, and increments R5 by 960. const-struc is an expression evaluating to a constant in the range 0-4095. Store R3 as halfword data into address in R4, then increment R4 by 4 Load R8 from a word 32 bytes above the address in R3, and load R9 from a word 36 bytes above the address in R3 Store R0 to address in R8, and store R1 to a word 4 bytes above the address in R8, and then decrement R8 by 16. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 93 12.11.3 LDR and STR, register offset Load and Store with register offset. 12.11.3.1 Syntax op{type}{cond} Rt, [Rn, Rm {, LSL #n}] where: op is one of: LDR Load Register. STR Store Register. type is one of: B unsigned byte, zero extend to 32 bits on loads. SB signed byte, sign extend to 32 bits (LDR only). H unsigned halfword, zero extend to 32 bits on loads. SH signed halfword, sign extend to 32 bits (LDR only). - omit, for word. cond is an optional condition code, see “Conditional execution” on page 87. Rt is the register to load or store. Rn is the register on which the memory address is based. Rm is a register containing a value to be used as the offset. LSL #n is an optional shift, with n in the range 0 to 3. 12.11.3.2 Operation LDR instructions load a register with a value from memory. STR instructions store a register value into memory. The memory address to load from or store to is at an offset from the register Rn. The offset is specified by the register Rm and can be shifted left by up to 3 bits using LSL. The value to load or store can be a byte, halfword, or word. For load instructions, bytes and halfwords can either be signed or unsigned. See “Address alignment” on page 86. 12.11.3.3 Restrictions In these instructions:  Rn must not be PC  Rm must not be SP and must not be PC  Rt can be SP only for word loads and word stores  Rt can be PC only for word loads. When Rt is PC in a word load instruction:  bit[0] of the loaded value must be 1 for correct execution, and a branch occurs to this halfword-aligned address  if the instruction is conditional, it must be the last instruction in the IT block. 12.11.3.4 Condition flags These instructions do not change the flags. 94 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.11.3.5 Examples STR LDRSB STR R0, [R5, R1] ; ; R0, [R5, R1, LSL #1] ; ; ; R0, [R1, R2, LSL #2] ; ; Store value of R0 into an address equal to sum of R5 and R1 Read byte value from an address equal to sum of R5 and two times R1, sign extended it to a word value and put it in R0 Stores R0 to an address equal to sum of R1 and four times R2 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 95 12.11.4 LDR and STR, unprivileged Load and Store with unprivileged access. 12.11.4.1 Syntax op{type}T{cond} Rt, [Rn {, #offset}] ; immediate offset where: op is one of: LDR Load Register. STR Store Register. type is one of: B unsigned byte, zero extend to 32 bits on loads. SB signed byte, sign extend to 32 bits (LDR only). H unsigned halfword, zero extend to 32 bits on loads. SH signed halfword, sign extend to 32 bits (LDR only). - omit, for word. cond is an optional condition code, see “Conditional execution” on page 87. Rt is the register to load or store. Rn is the register on which the memory address is based. offset is an offset from Rn and can be 0 to 255. If offset is omitted, the address is the value in Rn. 12.11.4.2 Operation These load and store instructions perform the same function as the memory access instructions with immediate offset, see “LDR and STR, immediate offset” on page 92. The difference is that these instructions have only unprivileged access even when used in privileged software. When used in unprivileged software, these instructions behave in exactly the same way as normal memory access instructions with immediate offset. 12.11.4.3 Restrictions In these instructions:  Rn must not be PC  Rt must not be SP and must not be PC. 12.11.4.4 Condition flags These instructions do not change the flags. 12.11.4.5 Examples 96 STRBTEQ R4, [R7] LDRHT R2, [R2, #8] ; ; ; ; Conditionally store least significant byte in R4 to an address in R7, with unprivileged access Load halfword value from an address equal to sum of R2 and 8 into R2, with unprivileged access SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.11.5 LDR, PC-relative Load register from memory. 12.11.5.1 Syntax LDR{type}{cond} Rt, label LDRD{cond} Rt, Rt2, label ; Load two words where: type is one of: B unsigned byte, zero extend to 32 bits. SB signed byte, sign extend to 32 bits. H unsigned halfword, zero extend to 32 bits. SH signed halfword, sign extend to 32 bits. - omit, for word. cond is an optional condition code, see “Conditional execution” on page 87. Rt is the register to load or store. Rt2 is the second register to load or store. label is a PC-relative expression. See “PC-relative expressions” on page 86. 12.11.5.2 Operation LDR loads a register with a value from a PC-relative memory address. The memory address is specified by a label or by an offset from the PC. The value to load or store can be a byte, halfword, or word. For load instructions, bytes and halfwords can either be signed or unsigned. See “Address alignment” on page 86. label must be within a limited range of the current instruction. Table 12-19 shows the possible offsets between label and the PC. Table 12-19. Offset ranges Instruction type Offset range Word, halfword, signed halfword, byte, signed byte −4095 to 4095 Two words −1020 to 1020 You might have to use the .W suffix to get the maximum offset range. See “Instruction width selection” on page 88. 12.11.5.3 Restrictions In these instructions:  Rt can be SP or PC only for word loads  Rt2 must not be SP and must not be PC  Rt must be different from Rt2. When Rt is PC in a word load instruction:  bit[0] of the loaded value must be 1 for correct execution, and a branch occurs to this halfword-aligned address  if the instruction is conditional, it must be the last instruction in the IT block. 12.11.5.4 Condition flags These instructions do not change the flags. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 97 12.11.5.5 Examples 98 LDR R0, LookUpTable LDRSB R7, localdata ; ; ; ; ; Load R0 with a word of data from an address labelled as LookUpTable Load a byte value from an address labelled as localdata, sign extend it to a word value, and put it in R7 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.11.6 LDM and STM Load and Store Multiple registers. 12.11.6.1 Syntax op{addr_mode}{cond} Rn{!}, reglist where: op is one of: LDM Load Multiple registers. STM Store Multiple registers. addr_mode is any one of the following: IA Increment address After each access. This is the default. DB Decrement address Before each access. cond is an optional condition code, see “Conditional execution” on page 87. Rn is the register on which the memory addresses are based. ! is an optional writeback suffix. If ! is present the final address, that is loaded from or stored to, is written back into Rn. reglist is a list of one or more registers to be loaded or stored, enclosed in braces. It can contain register ranges. It must be comma separated if it contains more than one register or register range, see “Examples” on page 100. LDM and LDMFD are synonyms for LDMIA. LDMFD refers to its use for popping data from Full Descending stacks. LDMEA is a synonym for LDMDB, and refers to its use for popping data from Empty Ascending stacks. STM and STMEA are synonyms for STMIA. STMEA refers to its use for pushing data onto Empty Ascending stacks. STMFD is s synonym for STMDB, and refers to its use for pushing data onto Full Descending stacks 12.11.6.2 Operation LDM instructions load the registers in reglist with word values from memory addresses based on Rn. STM instructions store the word values in the registers in reglist to memory addresses based on Rn. For LDM, LDMIA, LDMFD, STM, STMIA, and STMEA the memory addresses used for the accesses are at 4-byte intervals ranging from Rn to Rn + 4 * (n-1), where n is the number of registers in reglist. The accesses happens in order of increasing register numbers, with the lowest numbered register using the lowest memory address and the highest number register using the highest memory address. If the writeback suffix is specified, the value of Rn + 4 * (n-1) is written back to Rn. For LDMDB, LDMEA, STMDB, and STMFD the memory addresses used for the accesses are at 4-byte intervals ranging from Rn to Rn - 4 * (n-1), where n is the number of registers in reglist. The accesses happen in order of decreasing register numbers, with the highest numbered register using the highest memory address and the lowest number register using the lowest memory address. If the writeback suffix is specified, the value of Rn - 4 * (n-1) is written back to Rn. The PUSH and POP instructions can be expressed in this form. See “PUSH and POP” on page 101 for details. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 99 12.11.6.3 Restrictions In these instructions:  Rn must not be PC  reglist must not contain SP  in any STM instruction, reglist must not contain PC  in any LDM instruction, reglist must not contain PC if it contains LR  reglist must not contain Rn if you specify the writeback suffix. When PC is in reglist in an LDM instruction:  bit[0] of the value loaded to the PC must be 1 for correct execution, and a branch occurs to this halfwordaligned address  if the instruction is conditional, it must be the last instruction in the IT block. 12.11.6.4 Condition flags These instructions do not change the flags. 12.11.6.5 Examples LDM STMDB R8,{R0,R2,R9} ; LDMIA is a synonym for LDM R1!,{R3-R6,R11,R12} 12.11.6.6 Incorrect examples STM LDM 100 R5!,{R5,R4,R9} ; Value stored for R5 is unpredictable R2, {} ; There must be at least one register in the list SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.11.7 PUSH and POP Push registers onto, and pop registers off a full-descending stack. 12.11.7.1 Syntax PUSH{cond} reglist POP{cond} reglist where: cond is an optional condition code, see “Conditional execution” on page 87. reglist is a non-empty list of registers, enclosed in braces. It can contain register ranges. It must be comma separated if it contains more than one register or register range. PUSH and POP are synonyms for STMDB and LDM (or LDMIA) with the memory addresses for the access based on SP, and with the final address for the access written back to the SP. PUSH and POP are the preferred mnemonics in these cases. 12.11.7.2 Operation PUSH stores registers on the stack in order of decreasing the register numbers, with the highest numbered register using the highest memory address and the lowest numbered register using the lowest memory address. POP loads registers from the stack in order of increasing register numbers, with the lowest numbered register using the lowest memory address and the highest numbered register using the highest memory address. See “LDM and STM” on page 99 for more information. 12.11.7.3 Restrictions In these instructions:  reglist must not contain SP  for the PUSH instruction, reglist must not contain PC  for the POP instruction, reglist must not contain PC if it contains LR. When PC is in reglist in a POP instruction:  bit[0] of the value loaded to the PC must be 1 for correct execution, and a branch occurs to this halfwordaligned address  if the instruction is conditional, it must be the last instruction in the IT block. 12.11.7.4 Condition flags These instructions do not change the flags. 12.11.7.5 Examples PUSH PUSH POP {R0,R4-R7} {R2,LR} {R0,R10,PC} SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 101 12.11.8 LDREX and STREX Load and Store Register Exclusive. 12.11.8.1 Syntax LDREX{cond} Rt, [Rn {, #offset}] STREX{cond} Rd, Rt, [Rn {, #offset}] LDREXB{cond} Rt, [Rn] STREXB{cond} Rd, Rt, [Rn] LDREXH{cond} Rt, [Rn] STREXH{cond} Rd, Rt, [Rn] where: cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register for the returned status. Rt is the register to load or store. Rn is the register on which the memory address is based. offset is an optional offset applied to the value in Rn. If offset is omitted, the address is the value in Rn. 12.11.8.2 Operation LDREX, LDREXB, and LDREXH load a word, byte, and halfword respectively from a memory address. STREX, STREXB, and STREXH attempt to store a word, byte, and halfword respectively to a memory address. The address used in any Store-Exclusive instruction must be the same as the address in the most recently executed Load-exclusive instruction. The value stored by the Store-Exclusive instruction must also have the same data size as the value loaded by the preceding Load-exclusive instruction. This means software must always use a Load-exclusive instruction and a matching Store-Exclusive instruction to perform a synchronization operation, see “Synchronization primitives” on page 65 If an Store-Exclusive instruction performs the store, it writes 0 to its destination register. If it does not perform the store, it writes 1 to its destination register. If the Store-Exclusive instruction writes 0 to the destination register, it is guaranteed that no other process in the system has accessed the memory location between the Load-exclusive and Store-Exclusive instructions. For reasons of performance, keep the number of instructions between corresponding Load-Exclusive and StoreExclusive instruction to a minimum. The result of executing a Store-Exclusive instruction to an address that is different from that used in the preceding Load-Exclusive instruction is unpredictable. 12.11.8.3 Restrictions In these instructions:  do not use PC  do not use SP for Rd and Rt  for STREX, Rd must be different from both Rt and Rn  the value of offset must be a multiple of four in the range 0-1020. 12.11.8.4 Condition flags These instructions do not change the flags. 102 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.11.8.5 Examples MOV R1, #0x1 ; Initialize the ‘lock taken’ value LDREX CMP ITT STREXEQ CMPEQ BNE .... R0, R0, EQ R0, R0, try ; ; ; ; ; ; ; try [LockAddr] #0 R1, [LockAddr] #0 Load the lock value Is the lock free? IT instruction for STREXEQ and CMPEQ Try and claim the lock Did this succeed? No – try again Yes – we have the lock SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 103 12.11.9 CLREX Clear Exclusive. 12.11.9.1 Syntax CLREX{cond} where: cond is an optional condition code, see “Conditional execution” on page 87. 12.11.9.2 Operation Use CLREX to make the next STREX, STREXB, or STREXH instruction write 1 to its destination register and fail to perform the store. It is useful in exception handler code to force the failure of the store exclusive if the exception occurs between a load exclusive instruction and the matching store exclusive instruction in a synchronization operation. See “Synchronization primitives” on page 65 for more information. 12.11.9.3 Condition flags These instructions do not change the flags. 12.11.9.4 Examples CLREX 104 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.12 General data processing instructions Table 12-20 shows the data processing instructions: Table 12-20. Data processing instructions Mnemonic Brief description See ADC Add with Carry “ADD, ADC, SUB, SBC, and RSB” on page 106 ADD Add “ADD, ADC, SUB, SBC, and RSB” on page 106 ADDW Add “ADD, ADC, SUB, SBC, and RSB” on page 106 AND Logical AND “AND, ORR, EOR, BIC, and ORN” on page 108 ASR Arithmetic Shift Right “ASR, LSL, LSR, ROR, and RRX” on page 109 BIC Bit Clear “AND, ORR, EOR, BIC, and ORN” on page 108 CLZ Count leading zeros “CLZ” on page 111 CMN Compare Negative “CMP and CMN” on page 112 CMP Compare “CMP and CMN” on page 112 EOR Exclusive OR “AND, ORR, EOR, BIC, and ORN” on page 108 LSL Logical Shift Left “ASR, LSL, LSR, ROR, and RRX” on page 109 LSR Logical Shift Right “ASR, LSL, LSR, ROR, and RRX” on page 109 MOV Move “MOV and MVN” on page 113 MOVT Move Top “MOVT” on page 115 MOVW Move 16-bit constant “MOV and MVN” on page 113 MVN Move NOT “MOV and MVN” on page 113 ORN Logical OR NOT “AND, ORR, EOR, BIC, and ORN” on page 108 ORR Logical OR “AND, ORR, EOR, BIC, and ORN” on page 108 RBIT Reverse Bits “REV, REV16, REVSH, and RBIT” on page 116 REV Reverse byte order in a word “REV, REV16, REVSH, and RBIT” on page 116 REV16 Reverse byte order in each halfword “REV, REV16, REVSH, and RBIT” on page 116 REVSH Reverse byte order in bottom halfword and sign extend “REV, REV16, REVSH, and RBIT” on page 116 ROR Rotate Right “ASR, LSL, LSR, ROR, and RRX” on page 109 RRX Rotate Right with Extend “ASR, LSL, LSR, ROR, and RRX” on page 109 RSB Reverse Subtract “ADD, ADC, SUB, SBC, and RSB” on page 106 SBC Subtract with Carry “ADD, ADC, SUB, SBC, and RSB” on page 106 SUB Subtract “ADD, ADC, SUB, SBC, and RSB” on page 106 SUBW Subtract “ADD, ADC, SUB, SBC, and RSB” on page 106 TEQ Test Equivalence “TST and TEQ” on page 117 TST Test “TST and TEQ” on page 117 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 105 12.12.1 ADD, ADC, SUB, SBC, and RSB Add, Add with carry, Subtract, Subtract with carry, and Reverse Subtract. 12.12.1.1 Syntax op{S}{cond} {Rd,} Rn, Operand2 op{cond} {Rd,} Rn, #imm12 ; ADD and SUB only where: op is one of: ADD Add. ADC Add with Carry. SUB Subtract. SBC Subtract with Carry. RSB Reverse Subtract. S is an optional suffix. If S is specified, the condition code flags are updated on the result of the operation, see “Conditional execution” on page 87. cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. If Rd is omitted, the destination register is Rn. Rn is the register holding the first operand. Operand2 is a flexible second operand. See “Flexible second operand” on page 82 for details of the options. imm12 is any value in the range 0-4095. 12.12.1.2 Operation The ADD instruction adds the value of Operand2 or imm12 to the value in Rn. The ADC instruction adds the values in Rn and Operand2, together with the carry flag. The SUB instruction subtracts the value of Operand2 or imm12 from the value in Rn. The SBC instruction subtracts the value of Operand2 from the value in Rn. If the carry flag is clear, the result is reduced by one. The RSB instruction subtracts the value in Rn from the value of Operand2. This is useful because of the wide range of options for Operand2. Use ADC and SBC to synthesize multiword arithmetic, see “Multiword arithmetic examples” on page 107. See also “ADR” on page 91. ADDW is equivalent to the ADD syntax that uses the imm12 operand. SUBW is equivalent to the SUB syntax that uses the imm12 operand. 12.12.1.3 Restrictions In these instructions:  Operand2 must not be SP and must not be PC  Rd can be SP only in ADD and SUB, and only with the additional restrictions: Rn must also be SP ̶ any shift in Operand2 must be limited to a maximum of 3 bits using LSL  Rn can be SP only in ADD and SUB  Rd can be PC only in the ADD{cond} PC, PC, Rm instruction where: ̶ 106 ̶ you must not specify the S suffix SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 ̶ Rm must not be PC and must not be SP ̶  if the instruction is conditional, it must be the last instruction in the IT block with the exception of the ADD{cond} PC, PC, Rm instruction, Rn can be PC only in ADD and SUB, and only with the additional restrictions: ̶ you must not specify the S suffix ̶ the second operand must be a constant in the range 0 to 4095. ̶ ̶ When using the PC for an addition or a subtraction, bits[1:0] of the PC are rounded to b00 before performing the calculation, making the base address for the calculation word-aligned. ̶ If you want to generate the address of an instruction, you have to adjust the constant based on the value of the PC. ARM recommends that you use the ADR instruction instead of ADD or SUB with Rn equal to the PC, because your assembler automatically calculates the correct constant for the ADR instruction. When Rd is PC in the ADD{cond} PC, PC, Rm instruction:  bit[0] of the value written to the PC is ignored  a branch occurs to the address created by forcing bit[0] of that value to 0. 12.12.1.4 Condition flags If S is specified, these instructions update the N, Z, C and V flags according to the result. 12.12.1.5 Examples ADD SUBS RSB ADCHI R2, R1, R3 R8, R6, #240 R4, R4, #1280 R11, R0, R3 ; ; ; ; Sets the flags on the result Subtracts contents of R4 from 1280 Only executed if C flag set and Z flag clear 12.12.1.6 Multiword arithmetic examples 12.12.1.7 64-bit addition The example below shows two instructions that add a 64-bit integer contained in R2 and R3 to another 64-bit integer contained in R0 and R1, and place the result in R4 and R5. ADDS ADC R4, R0, R2 R5, R1, R3 ; add the least significant words ; add the most significant words with carry 12.12.1.8 96-bit subtraction Multiword values do not have to use consecutive registers. The example below shows instructions that subtract a 96-bit integer contained in R9, R1, and R11 from another contained in R6, R2, and R8. The example stores the result in R6, R9, and R2. SUBS SBCS SBC R6, R6, R9 R9, R2, R1 R2, R8, R11 ; subtract the least significant words ; subtract the middle words with carry ; subtract the most significant words with carry SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 107 12.12.2 AND, ORR, EOR, BIC, and ORN Logical AND, OR, Exclusive OR, Bit Clear, and OR NOT. 12.12.2.1 Syntax op{S}{cond} {Rd,} Rn, Operand2 where: op is one of: AND logical AND. ORR logical OR, or bit set. EOR logical Exclusive OR. BIC logical AND NOT, or bit clear. ORN logical OR NOT. S is an optional suffix. If S is specified, the condition code flags are updated on the result of the operation, see “Conditional execution” on page 87. cond is an optional condition code, see See “Conditional execution” on page 87.. Rd is the destination register. Rn is the register holding the first operand. Operand2 is a flexible second operand. See “Flexible second operand” on page 82 for details of the options. 12.12.2.2 Operation The AND, EOR, and ORR instructions perform bitwise AND, Exclusive OR, and OR operations on the values in Rn and Operand2. The BIC instruction performs an AND operation on the bits in Rn with the complements of the corresponding bits in the value of Operand2. The ORN instruction performs an OR operation on the bits in Rn with the complements of the corresponding bits in the value of Operand2. 12.12.2.3 Restrictions Do not use SP and do not use PC. 12.12.2.4 Condition flags If S is specified, these instructions:  update the N and Z flags according to the result  can update the C flag during the calculation of Operand2, see “Flexible second operand” on page 82  do not affect the V flag. 12.12.2.5 Examples AND ORREQ ANDS EORS BIC ORN ORNS 108 R9, R2, R9, R7, R0, R7, R7, R2, #0xFF00 R0, R5 R8, #0x19 R11, #0x18181818 R1, #0xab R11, R14, ROR #4 R11, R14, ASR #32 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.12.3 ASR, LSL, LSR, ROR, and RRX Arithmetic Shift Right, Logical Shift Left, Logical Shift Right, Rotate Right, and Rotate Right with Extend. 12.12.3.1 Syntax op{S}{cond} Rd, Rm, Rs op{S}{cond} Rd, Rm, #n RRX{S}{cond} Rd, Rm where: op is one of: ASR Arithmetic Shift Right. LSL Logical Shift Left. LSR Logical Shift Right. ROR Rotate Right. S is an optional suffix. If S is specified, the condition code flags are updated on the result of the operation, see “Conditional execution” on page 87. Rd is the destination register. Rm is the register holding the value to be shifted. Rs is the register holding the shift length to apply to the value in Rm. Only the least significant byte is used and can be in the range 0 to 255. n is the shift length. The range of shift length depends on the instruction: ASR shift length from 1 to 32 LSL shift length from 0 to 31 LSR shift length from 1 to 32 ROR shift length from 1 to 31. MOV{S}{cond} Rd, Rm is the preferred syntax for LSL{S}{cond} Rd, Rm, #0. 12.12.3.2 Operation ASR, LSL, LSR, and ROR move the bits in the register Rm to the left or right by the number of places specified by constant n or register Rs. RRX moves the bits in register Rm to the right by 1. In all these instructions, the result is written to Rd, but the value in register Rm remains unchanged. For details on what result is generated by the different instructions, see “Shift Operations” on page 83. 12.12.3.3 Restrictions Do not use SP and do not use PC. 12.12.3.4 Condition flags If S is specified:  these instructions update the N and Z flags according to the result  the C flag is updated to the last bit shifted out, except when the shift length is 0, see “Shift Operations” on page 83. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 109 12.12.3.5 Examples ASR LSLS LSR ROR RRX 110 R7, R1, R4, R4, R4, R8, R2, R5, R5, R5 #9 #3 #6 R6 ; ; ; ; ; Arithmetic shift right by 9 bits Logical shift left by 3 bits with flag update Logical shift right by 6 bits Rotate right by the value in the bottom byte of R6 Rotate right with extend SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.12.4 CLZ Count Leading Zeros. 12.12.4.1 Syntax CLZ{cond} Rd, Rm where: cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. Rm is the operand register. 12.12.4.2 Operation The CLZ instruction counts the number of leading zeros in the value in Rm and returns the result in Rd. The result value is 32 if no bits are set in the source register, and zero if bit[31] is set. 12.12.4.3 Restrictions Do not use SP and do not use PC. 12.12.4.4 Condition flags This instruction does not change the flags. 12.12.4.5 Examples CLZ CLZNE R4,R9 R2,R3 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 111 12.12.5 CMP and CMN Compare and Compare Negative. 12.12.5.1 Syntax CMP{cond} Rn, Operand2 CMN{cond} Rn, Operand2 where: cond is an optional condition code, see “Conditional execution” on page 87. Rn is the register holding the first operand. Operand2 is a flexible second operand. See “Flexible second operand” on page 82 for details of the options. 12.12.5.2 Operation These instructions compare the value in a register with Operand2. They update the condition flags on the result, but do not write the result to a register. The CMP instruction subtracts the value of Operand2 from the value in Rn. This is the same as a SUBS instruction, except that the result is discarded. The CMN instruction adds the value of Operand2 to the value in Rn. This is the same as an ADDS instruction, except that the result is discarded. 12.12.5.3 Restrictions In these instructions:  do not use PC  Operand2 must not be SP. 12.12.5.4 Condition flags These instructions update the N, Z, C and V flags according to the result. 12.12.5.5 Examples CMP CMN CMPGT 112 R2, R9 R0, #6400 SP, R7, LSL #2 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.12.6 MOV and MVN Move and Move NOT. 12.12.6.1 Syntax MOV{S}{cond} Rd, Operand2 MOV{cond} Rd, #imm16 MVN{S}{cond} Rd, Operand2 where: S is an optional suffix. If S is specified, the condition code flags are updated on the result of the operation, see “Conditional execution” on page 87. cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. Operand2 is a flexible second operand. See “Flexible second operand” on page 82 for details of the options. imm16 is any value in the range 0-65535. 12.12.6.2 Operation The MOV instruction copies the value of Operand2 into Rd. When Operand2 in a MOV instruction is a register with a shift other than LSL #0, the preferred syntax is the corresponding shift instruction:  ASR{S}{cond} Rd, Rm, #n is the preferred syntax for MOV{S}{cond} Rd, Rm, ASR #n  LSL{S}{cond} Rd, Rm, #n is the preferred syntax for MOV{S}{cond} Rd, Rm, LSL #n if n != 0  LSR{S}{cond} Rd, Rm, #n is the preferred syntax for MOV{S}{cond} Rd, Rm, LSR #n  ROR{S}{cond} Rd, Rm, #n is the preferred syntax for MOV{S}{cond} Rd, Rm, ROR #n  RRX{S}{cond} Rd, Rm is the preferred syntax for MOV{S}{cond} Rd, Rm, RRX. Also, the MOV instruction permits additional forms of Operand2 as synonyms for shift instructions:  MOV{S}{cond} Rd, Rm, ASR Rs is a synonym for ASR{S}{cond} Rd, Rm, Rs  MOV{S}{cond} Rd, Rm, LSL Rs is a synonym for LSL{S}{cond} Rd, Rm, Rs  MOV{S}{cond} Rd, Rm, LSR Rs is a synonym for LSR{S}{cond} Rd, Rm, Rs  MOV{S}{cond} Rd, Rm, ROR Rs is a synonym for ROR{S}{cond} Rd, Rm, Rs See “ASR, LSL, LSR, ROR, and RRX” on page 109. The MVN instruction takes the value of Operand2, performs a bitwise logical NOT operation on the value, and places the result into Rd. The MOVW instruction provides the same function as MOV, but is restricted to using the imm16 operand. 12.12.6.3 Restrictions You can use SP and PC only in the MOV instruction, with the following restrictions:  the second operand must be a register without shift  you must not specify the S suffix. When Rd is PC in a MOV instruction:  bit[0] of the value written to the PC is ignored  a branch occurs to the address created by forcing bit[0] of that value to 0. Though it is possible to use MOV as a branch instruction, ARM strongly recommends the use of a BX or BLX instruction to branch for software portability to the ARM instruction set. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 113 12.12.6.4 Condition flags If S is specified, these instructions:  update the N and Z flags according to the result  can update the C flag during the calculation of Operand2, see “Flexible second operand” on page 82  do not affect the V flag. 12.12.6.5 Example MOVS MOV MOVS MOV MOV MVNS 114 R11, #0x000B R1, #0xFA05 R10, R12 R3, #23 R8, SP R2, #0xF ; ; ; ; ; ; ; Write value of 0x000B to R11, flags get updated Write value of 0xFA05 to R1, flags are not updated Write value in R12 to R10, flags get updated Write value of 23 to R3 Write value of stack pointer to R8 Write value of 0xFFFFFFF0 (bitwise inverse of 0xF) to the R2 and update flags SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.12.7 MOVT Move Top. 12.12.7.1 Syntax MOVT{cond} Rd, #imm16 where: cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. imm16 is a 16-bit immediate constant. 12.12.7.2 Operation MOVT writes a 16-bit immediate value, imm16, to the top halfword, Rd[31:16], of its destination register. The write does not affect Rd[15:0]. The MOV, MOVT instruction pair enables you to generate any 32-bit constant. 12.12.7.3 Restrictions Rd must not be SP and must not be PC. 12.12.7.4 Condition flags This instruction does not change the flags. 12.12.7.5 Examples MOVT R3, #0xF123 ; Write 0xF123 to upper halfword of R3, lower halfword ; and APSR are unchanged SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 115 12.12.8 REV, REV16, REVSH, and RBIT Reverse bytes and Reverse bits. 12.12.8.1 Syntax op{cond} Rd, Rn where: op is any of: REV Reverse byte order in a word. REV16 Reverse byte order in each halfword independently. REVSH Reverse byte order in the bottom halfword, and sign extend to 32 bits. RBIT Reverse the bit order in a 32-bit word. cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. Rn is the register holding the operand. 12.12.8.2 Operation Use these instructions to change endianness of data: REV converts 32-bit big-endian data into little-endian data or 32-bit little-endian data into big-endian data. REV16 converts 16-bit big-endian data into little-endian data or 16-bit little-endian data into big-endian data. REVSH converts either: 16-bit signed big-endian data into 32-bit signed little-endian data 16-bit signed little-endian data into 32-bit signed big-endian data. 12.12.8.3 Restrictions Do not use SP and do not use PC. 12.12.8.4 Condition flags These instructions do not change the flags. 12.12.8.5 Examples REV REV16 REVSH REVHS RBIT 116 R3, R0, R0, R3, R7, R7 R0 R5 R7 R8 ; ; ; ; ; Reverse Reverse Reverse Reverse Reverse byte order of value in R7 and write it to R3 byte order of each 16-bit halfword in R0 Signed Halfword with Higher or Same condition bit order of value in R8 and write the result to R7 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.12.9 TST and TEQ Test bits and Test Equivalence. 12.12.9.1 Syntax TST{cond} Rn, Operand2 TEQ{cond} Rn, Operand2 where: cond is an optional condition code, see “Conditional execution” on page 87. Rn is the register holding the first operand. Operand2 is a flexible second operand. See “Flexible second operand” on page 82 for details of the options. 12.12.9.2 Operation These instructions test the value in a register against Operand2. They update the condition flags based on the result, but do not write the result to a register. The TST instruction performs a bitwise AND operation on the value in Rn and the value of Operand2. This is the same as the ANDS instruction, except that it discards the result. To test whether a bit of Rn is 0 or 1, use the TST instruction with an Operand2 constant that has that bit set to 1 and all other bits cleared to 0. The TEQ instruction performs a bitwise Exclusive OR operation on the value in Rn and the value of Operand2. This is the same as the EORS instruction, except that it discards the result. Use the TEQ instruction to test if two values are equal without affecting the V or C flags. TEQ is also useful for testing the sign of a value. After the comparison, the N flag is the logical Exclusive OR of the sign bits of the two operands. 12.12.9.3 Restrictions Do not use SP and do not use PC. 12.12.9.4 Condition flags These instructions:  update the N and Z flags according to the result  can update the C flag during the calculation of Operand2, see “Flexible second operand” on page 82  do not affect the V flag. 12.12.9.5 Examples TST R0, #0x3F8 TEQEQ R10, R9 ; ; ; ; Perform bitwise AND of R0 value to 0x3F8, APSR is updated but result is discarded Conditionally test if value in R10 is equal to value in R9, APSR is updated but result is discarded SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 117 12.13 Multiply and divide instructions Table 12-21 shows the multiply and divide instructions: Table 12-21. Multiply and divide instructions Mnemonic Brief description See MLA Multiply with Accumulate, 32-bit result “MUL, MLA, and MLS” on page 119 MLS Multiply and Subtract, 32-bit result “MUL, MLA, and MLS” on page 119 MUL Multiply, 32-bit result “MUL, MLA, and MLS” on page 119 SDIV Signed Divide “SDIV and UDIV” on page 121 SMLAL Signed Multiply with Accumulate (32x32+64), 64-bit result “UMULL, UMLAL, SMULL, and SMLAL” on page 120 SMULL Signed Multiply (32x32), 64-bit result “UMULL, UMLAL, SMULL, and SMLAL” on page 120 UDIV Unsigned Divide “SDIV and UDIV” on page 121 UMLAL Unsigned Multiply with Accumulate (32x32+64), 64-bit result “UMULL, UMLAL, SMULL, and SMLAL” on page 120 UMULL Unsigned Multiply (32x32), 64-bit result “UMULL, UMLAL, SMULL, and SMLAL” on page 120 118 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.13.1 MUL, MLA, and MLS Multiply, Multiply with Accumulate, and Multiply with Subtract, using 32-bit operands, and producing a 32-bit result. 12.13.1.1 Syntax MUL{S}{cond} {Rd,} Rn, Rm ; Multiply MLA{cond} Rd, Rn, Rm, Ra ; Multiply with accumulate MLS{cond} Rd, Rn, Rm, Ra ; Multiply with subtract where: cond is an optional condition code, see “Conditional execution” on page 87. S is an optional suffix. If S is specified, the condition code flags are updated on the result of the operation, see “Conditional execution” on page 87. Rd is the destination register. If Rd is omitted, the destination register is Rn. Rn, Rm are registers holding the values to be multiplied. Ra is a register holding the value to be added or subtracted from. 12.13.1.2 Operation The MUL instruction multiplies the values from Rn and Rm, and places the least significant 32 bits of the result in Rd. The MLA instruction multiplies the values from Rn and Rm, adds the value from Ra, and places the least significant 32 bits of the result in Rd. The MLS instruction multiplies the values from Rn and Rm, subtracts the product from the value from Ra, and places the least significant 32 bits of the result in Rd. The results of these instructions do not depend on whether the operands are signed or unsigned. 12.13.1.3 Restrictions In these instructions, do not use SP and do not use PC. If you use the S suffix with the MUL instruction:  Rd, Rn, and Rm must all be in the range R0 to R7  Rd must be the same as Rm  you must not use the cond suffix. 12.13.1.4 Condition flags If S is specified, the MUL instruction:  updates the N and Z flags according to the result  does not affect the C and V flags. 12.13.1.5 Examples MUL MLA MULS MULLT MLS R10, R2, R5 R10, R2, R1, R5 R0, R2, R2 R2, R3, R2 R4, R5, R6, R7 ; ; ; ; ; Multiply, R10 Multiply with Multiply with Conditionally Multiply with = R2 x R5 accumulate, R10 = flag update, R0 = multiply, R2 = R3 subtract, R4 = R7 (R2 x R1) + R5 R2 x R2 x R2 - (R5 x R6) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 119 12.13.2 UMULL, UMLAL, SMULL, and SMLAL Signed and Unsigned Long Multiply, with optional Accumulate, using 32-bit operands and producing a 64-bit result. 12.13.2.1 Syntax op{cond} RdLo, RdHi, Rn, Rm where: op is one of: UMULL Unsigned Long Multiply. UMLAL Unsigned Long Multiply, with Accumulate. SMULL Signed Long Multiply. SMLAL Signed Long Multiply, with Accumulate. cond is an optional condition code, see “Conditional execution” on page 87. RdHi, RdLo are the destination registers. For UMLAL and SMLAL they also hold the accumulating value. Rn, Rm are registers holding the operands. 12.13.2.2 Operation The UMULL instruction interprets the values from Rn and Rm as unsigned integers. It multiplies these integers and places the least significant 32 bits of the result in RdLo, and the most significant 32 bits of the result in RdHi. The UMLAL instruction interprets the values from Rn and Rm as unsigned integers. It multiplies these integers, adds the 64-bit result to the 64-bit unsigned integer contained in RdHi and RdLo, and writes the result back to RdHi and RdLo. The SMULL instruction interprets the values from Rn and Rm as two’s complement signed integers. It multiplies these integers and places the least significant 32 bits of the result in RdLo, and the most significant 32 bits of the result in RdHi. The SMLAL instruction interprets the values from Rn and Rm as two’s complement signed integers. It multiplies these integers, adds the 64-bit result to the 64-bit signed integer contained in RdHi and RdLo, and writes the result back to RdHi and RdLo. 12.13.2.3 Restrictions In these instructions:  do not use SP and do not use PC  RdHi and RdLo must be different registers. 12.13.2.4 Condition flags These instructions do not affect the condition code flags. 12.13.2.5 Examples UMULL SMLAL 120 R0, R4, R5, R6 R4, R5, R3, R8 ; Unsigned (R4,R0) = R5 x R6 ; Signed (R5,R4) = (R5,R4) + R3 x R8 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.13.3 SDIV and UDIV Signed Divide and Unsigned Divide. 12.13.3.1 Syntax SDIV{cond} {Rd,} Rn, Rm UDIV{cond} {Rd,} Rn, Rm where: cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. If Rd is omitted, the destination register is Rn. Rn is the register holding the value to be divided. Rm is a register holding the divisor. 12.13.3.2 Operation SDIV performs a signed integer division of the value in Rn by the value in Rm. UDIV performs an unsigned integer division of the value in Rn by the value in Rm. For both instructions, if the value in Rn is not divisible by the value in Rm, the result is rounded towards zero. 12.13.3.3 Restrictions Do not use SP and do not use PC. 12.13.3.4 Condition flags These instructions do not change the flags. 12.13.3.5 Examples SDIV UDIV R0, R2, R4 R8, R8, R1 ; Signed divide, R0 = R2/R4 ; Unsigned divide, R8 = R8/R1 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 121 12.14 Saturating instructions This section describes the saturating instructions, SSAT and USAT. 12.14.1 SSAT and USAT Signed Saturate and Unsigned Saturate to any bit position, with optional shift before saturating. 12.14.1.1 Syntax op{cond} Rd, #n, Rm {, shift #s} where: op is one of: SSAT Saturates a signed value to a signed range. USAT Saturates a signed value to an unsigned range. cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. n specifies the bit position to saturate to: n ranges from 1 to 32 for SSAT n ranges from 0 to 31 for USAT. Rm is the register containing the value to saturate. shift #s is an optional shift applied to Rm before saturating. It must be one of the following: ASR #s where s is in the range 1 to 31 LSL #s where s is in the range 0 to 31. 12.14.1.2 Operation These instructions saturate to a signed or unsigned n-bit value. The SSAT instruction applies the specified shift, then saturates to the signed range −2n–1 ≤ x ≤ 2n–1−1. The USAT instruction applies the specified shift, then saturates to the unsigned range 0 ≤ x ≤ 2n−1. For signed n-bit saturation using SSAT, this means that:  if the value to be saturated is less than −2n−1, the result returned is −2n-1  if the value to be saturated is greater than 2n−1−1, the result returned is 2n-1−1  otherwise, the result returned is the same as the value to be saturated. For unsigned n-bit saturation using USAT, this means that:  if the value to be saturated is less than 0, the result returned is 0  if the value to be saturated is greater than 2n−1, the result returned is 2n−1  otherwise, the result returned is the same as the value to be saturated. If the returned result is different from the value to be saturated, it is called saturation. If saturation occurs, the instruction sets the Q flag to 1 in the APSR. Otherwise, it leaves the Q flag unchanged. To clear the Q flag to 0, you must use the MSR instruction, see “MSR” on page 142. To read the state of the Q flag, use the MRS instruction, see “MRS” on page 141. 12.14.1.3 Restrictions Do not use SP and do not use PC. 12.14.1.4 Condition flags These instructions do not affect the condition code flags. 122 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 If saturation occurs, these instructions set the Q flag to 1. 12.14.1.5 Examples SSAT R7, #16, R7, LSL #4 USATNE R0, #7, R5 ; ; ; ; ; Logical shift left value in R7 by 4, then saturate it as a signed 16-bit value and write it back to R7 Conditionally saturate value in R5 as an unsigned 7 bit value and write it to R0 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 123 12.15 Bitfield instructions Table 12-22 shows the instructions that operate on adjacent sets of bits in registers or bitfields: Table 12-22. 124 Packing and unpacking instructions Mnemonic Brief description See BFC Bit Field Clear “BFC and BFI” on page 125 BFI Bit Field Insert “BFC and BFI” on page 125 SBFX Signed Bit Field Extract “SBFX and UBFX” on page 126 SXTB Sign extend a byte “SXT and UXT” on page 127 SXTH Sign extend a halfword “SXT and UXT” on page 127 UBFX Unsigned Bit Field Extract “SBFX and UBFX” on page 126 UXTB Zero extend a byte “SXT and UXT” on page 127 UXTH Zero extend a halfword “SXT and UXT” on page 127 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.15.1 BFC and BFI Bit Field Clear and Bit Field Insert. 12.15.1.1 Syntax BFC{cond} Rd, #lsb, #width BFI{cond} Rd, Rn, #lsb, #width where: cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. Rn is the source register. lsb is the position of the least significant bit of the bitfield. lsb must be in the range 0 to 31. width is the width of the bitfield and must be in the range 1 to 32−lsb. 12.15.1.2 Operation BFC clears a bitfield in a register. It clears width bits in Rd, starting at the low bit position lsb. Other bits in Rd are unchanged. BFI copies a bitfield into one register from another register. It replaces width bits in Rd starting at the low bit position lsb, with width bits from Rn starting at bit[0]. Other bits in Rd are unchanged. 12.15.1.3 Restrictions Do not use SP and do not use PC. 12.15.1.4 Condition flags These instructions do not affect the flags. 12.15.1.5 Examples BFC BFI R4, #8, #12 R9, R2, #8, #12 ; Clear bit 8 to bit 19 (12 bits) of R4 to 0 ; Replace bit 8 to bit 19 (12 bits) of R9 with ; bit 0 to bit 11 from R2 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 125 12.15.2 SBFX and UBFX Signed Bit Field Extract and Unsigned Bit Field Extract. 12.15.2.1 Syntax SBFX{cond} Rd, Rn, #lsb, #width UBFX{cond} Rd, Rn, #lsb, #width where: cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. Rn is the source register. lsb is the position of the least significant bit of the bitfield. lsb must be in the range 0 to 31. width is the width of the bitfield and must be in the range 1 to 32−lsb. 12.15.2.2 Operation SBFX extracts a bitfield from one register, sign extends it to 32 bits, and writes the result to the destination register. UBFX extracts a bitfield from one register, zero extends it to 32 bits, and writes the result to the destination register. 12.15.2.3 Restrictions Do not use SP and do not use PC. 12.15.2.4 Condition flags These instructions do not affect the flags. 12.15.2.5 Examples SBFX UBFX 126 R0, R1, #20, #4 ; ; R8, R11, #9, #10 ; ; Extract bit 20 to bit 23 (4 bits) from R1 and sign extend to 32 bits and then write the result to R0. Extract bit 9 to bit 18 (10 bits) from R11 and zero extend to 32 bits and then write the result to R8 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.15.3 SXT and UXT Sign extend and Zero extend. 12.15.3.1 Syntax SXTextend{cond} {Rd,} Rm {, ROR #n} UXTextend{cond} {Rd}, Rm {, ROR #n} where: extend is one of: B Extends an 8-bit value to a 32-bit value. H Extends a 16-bit value to a 32-bit value. cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. Rm is the register holding the value to extend. ROR #n is one of: ROR #8 Value from Rm is rotated right 8 bits. ROR #16 Value from Rm is rotated right 16 bits. ROR #24 Value from Rm is rotated right 24 bits. If ROR #n is omitted, no rotation is performed. 12.15.3.2 Operation These instructions do the following:  Rotate the value from Rm right by 0, 8, 16 or 24 bits.  Extract bits from the resulting value: SXTB extracts bits[7:0] and sign extends to 32 bits. UXTB extracts bits[7:0] and zero extends to 32 bits. SXTH extracts bits[15:0] and sign extends to 32 bits. UXTH extracts bits[15:0] and zero extends to 32 bits. 12.15.3.3 Restrictions Do not use SP and do not use PC. 12.15.3.4 Condition flags These instructions do not affect the flags. 12.15.3.5 Examples SXTH R4, R6, ROR #16 UXTB R3, R10 ; ; ; ; ; Rotate R6 right by 16 bits, then obtain the lower halfword of the result and then sign extend to 32 bits and write the result to R4. Extract lowest byte of the value in R10 and zero extend it, and write the result to R3 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 127 12.16 Branch and control instructions Table 12-23 shows the branch and control instructions: Table 12-23. 128 Branch and control instructions Mnemonic Brief description See B Branch “B, BL, BX, and BLX” on page 129 BL Branch with Link “B, BL, BX, and BLX” on page 129 BLX Branch indirect with Link “B, BL, BX, and BLX” on page 129 BX Branch indirect “B, BL, BX, and BLX” on page 129 CBNZ Compare and Branch if Non Zero “CBZ and CBNZ” on page 131 CBZ Compare and Branch if Non Zero “CBZ and CBNZ” on page 131 IT If-Then “IT” on page 132 TBB Table Branch Byte “TBB and TBH” on page 134 TBH Table Branch Halfword “TBB and TBH” on page 134 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.16.1 B, BL, BX, and BLX Branch instructions. 12.16.1.1 Syntax B{cond} label BL{cond} label BX{cond} Rm BLX{cond} Rm where: B is branch (immediate). BL is branch with link (immediate). BX is branch indirect (register). BLX is branch indirect with link (register). cond is an optional condition code, see “Conditional execution” on page 87. label is a PC-relative expression. See “PC-relative expressions” on page 86. Rm is a register that indicates an address to branch to. Bit[0] of the value in Rm must be 1, but the address to branch to is created by changing bit[0] to 0. 12.16.1.2 Operation All these instructions cause a branch to label, or to the address indicated in Rm. In addition:  The BL and BLX instructions write the address of the next instruction to LR (the link register, R14).  The BX and BLX instructions cause a UsageFault exception if bit[0] of Rm is 0. Bcond label is the only conditional instruction that can be either inside or outside an IT block. All other branch instructions must be conditional inside an IT block, and must be unconditional outside the IT block, see “IT” on page 132. Table 12-24 shows the ranges for the various branch instructions. Table 12-24. Branch ranges Instruction Branch range B label −16 MB to +16 MB Bcond label (outside IT block) −1 MB to +1 MB Bcond label (inside IT block) −16 MB to +16 MB BL{cond} label −16 MB to +16 MB BX{cond} Rm Any value in register BLX{cond} Rm Any value in register You might have to use the .W suffix to get the maximum branch range. See “Instruction width selection” on page 88. 12.16.1.3 Restrictions The restrictions are:  do not use PC in the BLX instruction  for BX and BLX, bit[0] of Rm must be 1 for correct execution but a branch occurs to the target address created by changing bit[0] to 0  when any of these instructions is inside an IT block, it must be the last instruction of the IT block. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 129 Bcond is the only conditional instruction that is not required to be inside an IT block. However, it has a longer branch range when it is inside an IT block. 12.16.1.4 Condition flags These instructions do not change the flags. 12.16.1.5 Examples 130 B BLE B.W BEQ BEQ.W BL loopA ng target target target funC BX BXNE BLX LR R0 R0 ; ; ; ; ; ; ; ; ; ; ; Branch to loopA Conditionally branch to label ng Branch to target within 16MB range Conditionally branch to target Conditionally branch to target within 1MB Branch with link (Call) to function funC, return address stored in LR Return from function call Conditionally branch to address stored in R0 Branch with link and exchange (Call) to a address stored in R0 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.16.2 CBZ and CBNZ Compare and Branch on Zero, Compare and Branch on Non-Zero. 12.16.2.1 Syntax CBZ Rn, label CBNZ Rn, label where: Rn is the register holding the operand. label is the branch destination. 12.16.2.2 Operation Use the CBZ or CBNZ instructions to avoid changing the condition code flags and to reduce the number of instructions. CBZ Rn, label does not change condition flags but is otherwise equivalent to: CMP Rn, #0 BEQ label CBNZ Rn, label does not change condition flags but is otherwise equivalent to: CMP Rn, #0 BNE label 12.16.2.3 Restrictions The restrictions are:  Rn must be in the range of R0 to R7  the branch destination must be within 4 to 130 bytes after the instruction  these instructions must not be used inside an IT block. 12.16.2.4 Condition flags These instructions do not change the flags. 12.16.2.5 Examples CBZ CBNZ R5, target ; Forward branch if R5 is zero R0, target ; Forward branch if R0 is not zero SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 131 12.16.3 IT If-Then condition instruction. 12.16.3.1 Syntax IT{x{y{z}}} cond where: x specifies the condition switch for the second instruction in the IT block. y specifies the condition switch for the third instruction in the IT block. z specifies the condition switch for the fourth instruction in the IT block. cond specifies the condition for the first instruction in the IT block. The condition switch for the second, third and fourth instruction in the IT block can be either: T Then. Applies the condition cond to the instruction. E Else. Applies the inverse condition of cond to the instruction. It is possible to use AL (the always condition) for cond in an IT instruction. If this is done, all of the instructions in the IT block must be unconditional, and each of x, y, and z must be T or omitted but not E. 12.16.3.2 Operation The IT instruction makes up to four following instructions conditional. The conditions can be all the same, or some of them can be the logical inverse of the others. The conditional instructions following the IT instruction form the IT block. The instructions in the IT block, including any branches, must specify the condition in the {cond} part of their syntax. Your assembler might be able to generate the required IT instructions for conditional instructions automatically, so that you do not need to write them yourself. See your assembler documentation for details. A BKPT instruction in an IT block is always executed, even if its condition fails. Exceptions can be taken between an IT instruction and the corresponding IT block, or within an IT block. Such an exception results in entry to the appropriate exception handler, with suitable return information in LR and stacked PSR. Instructions designed for use for exception returns can be used as normal to return from the exception, and execution of the IT block resumes correctly. This is the only way that a PC-modifying instruction is permitted to branch to an instruction in an IT block. 12.16.3.3 Restrictions The following instructions are not permitted in an IT block:  IT  CBZ and CBNZ  CPSID and CPSIE. Other restrictions when using an IT block are:  132 a branch or any instruction that modifies the PC must either be outside an IT block or must be the last instruction inside the IT block. These are: ̶ ADD PC, PC, Rm ̶ MOV PC, Rm ̶ B, BL, BX, BLX ̶ any LDM, LDR, or POP instruction that writes to the PC ̶ TBB and TBH SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15  do not branch to any instruction inside an IT block, except when returning from an exception handler  all conditional instructions except Bcond must be inside an IT block. Bcond can be either outside or inside an IT block but has a larger branch range if it is inside one  each instruction inside the IT block must specify a condition code suffix that is either the same or logical inverse as for the other instructions in the block. Your assembler might place extra restrictions on the use of IT blocks, such as prohibiting the use of assembler directives within them. 12.16.3.4 Condition flags This instruction does not change the flags. 12.16.3.5 Example ITTE ANDNE ADDSNE MOVEQ NE R0, R0, R1 R2, R2, #1 R2, R3 ; ; ; ; Next 3 instructions are conditional ANDNE does not update condition flags ADDSNE updates condition flags Conditional move CMP R0, #9 ITE ADDGT ADDLE GT R1, R0, #55 R1, R0, #48 ; ; ; ; ; Convert R0 hex value (0 to 15) into ASCII ('0'-'9', 'A'-'F') Next 2 instructions are conditional Convert 0xA -> 'A' Convert 0x0 -> '0' IT GT ; IT block with only one conditional instruction ADDGT R1, R1, #1 ; Increment R1 conditionally ITTEE MOVEQ ADDEQ ANDNE BNE.W EQ R0, R1 R2, R2, #10 R3, R3, #1 dloop ; ; ; ; ; ; IT ADD NE R0, R0, R1 ; Next instruction is conditional ; Syntax error: no condition code used in IT block Next 4 instructions are conditional Conditional move Conditional add Conditional AND Branch instruction can only be used in the last instruction of an IT block SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 133 12.16.4 TBB and TBH Table Branch Byte and Table Branch Halfword. 12.16.4.1 Syntax TBB [Rn, Rm] TBH [Rn, Rm, LSL #1] where: Rn is the register containing the address of the table of branch lengths. If Rn is PC, then the address of the table is the address of the byte immediately following the TBB or TBH instruction. Rm is the index register. This contains an index into the table. For halfword tables, LSL #1 doubles the value in Rm to form the right offset into the table. 12.16.4.2 Operation These instructions cause a PC-relative forward branch using a table of single byte offsets for TBB, or halfword offsets for TBH. Rn provides a pointer to the table, and Rm supplies an index into the table. For TBB the branch offset is twice the unsigned value of the byte returned from the table. and for TBH the branch offset is twice the unsigned value of the halfword returned from the table. The branch occurs to the address at that offset from the address of the byte immediately after the TBB or TBH instruction. 12.16.4.3 Restrictions The restrictions are:  Rn must not be SP  Rm must not be SP and must not be PC  when any of these instructions is used inside an IT block, it must be the last instruction of the IT block. 12.16.4.4 Condition flags These instructions do not change the flags. 12.16.4.5 Examples ADR.W R0, BranchTable_Byte TBB [R0, R1] ; R1 is the index, R0 is the base address of the ; branch table Case1 ; an instruction sequence follows Case2 ; an instruction sequence follows Case3 ; an instruction sequence follows BranchTable_Byte DCB 0 ; Case1 offset calculation DCB ((Case2-Case1)/2) ; Case2 offset calculation DCB ((Case3-Case1)/2) ; Case3 offset calculation TBH [PC, R1, LSL #1] ; R1 is the index, PC is used as base of the ; branch table BranchTable_H DCI ((CaseA - BranchTable_H)/2) ; CaseA offset calculation DCI ((CaseB - BranchTable_H)/2) ; CaseB offset calculation DCI ((CaseC - BranchTable_H)/2) ; CaseC offset calculation CaseA ; an instruction sequence follows CaseB ; an instruction sequence follows CaseC ; an instruction sequence follows 134 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.17 Miscellaneous instructions Table 12-25 shows the remaining Cortex-M3 instructions: Table 12-25. Miscellaneous instructions Mnemonic Brief description See BKPT Breakpoint “BKPT” on page 136 CPSID Change Processor State, Disable Interrupts “CPS” on page 137 CPSIE Change Processor State, Enable Interrupts “CPS” on page 137 DMB Data Memory Barrier “DMB” on page 138 DSB Data Synchronization Barrier “DSB” on page 139 ISB Instruction Synchronization Barrier “ISB” on page 140 MRS Move from special register to register “MRS” on page 141 MSR Move from register to special register “MSR” on page 142 NOP No Operation “NOP” on page 143 SEV Send Event “SEV” on page 144 SVC Supervisor Call “SVC” on page 145 WFE Wait For Event “WFE” on page 146 WFI Wait For Interrupt “WFI” on page 147 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 135 12.17.1 BKPT Breakpoint. 12.17.1.1 Syntax BKPT #imm where: imm is an expression evaluating to an integer in the range 0-255 (8-bit value). 12.17.1.2 Operation The BKPT instruction causes the processor to enter Debug state. Debug tools can use this to investigate system state when the instruction at a particular address is reached. imm is ignored by the processor. If required, a debugger can use it to store additional information about the breakpoint. The BKPT instruction can be placed inside an IT block, but it executes unconditionally, unaffected by the condition specified by the IT instruction. 12.17.1.3 Condition flags This instruction does not change the flags. 12.17.1.4 Examples BKPT 0xAB 136 ; Breakpoint with immediate value set to 0xAB (debugger can ; extract the immediate value by locating it using the PC) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.17.2 CPS Change Processor State. 12.17.2.1 Syntax CPSeffect iflags where: effect is one of: IE Clears the special purpose register. ID Sets the special purpose register. iflags is a sequence of one or more flags: i Set or clear PRIMASK. f Set or clear FAULTMASK. 12.17.2.2 Operation CPS changes the PRIMASK and FAULTMASK special register values. See “Exception mask registers” on page 52 for more information about these registers. 12.17.2.3 Restrictions The restrictions are:  use CPS only from privileged software, it has no effect if used in unprivileged software  CPS cannot be conditional and so must not be used inside an IT block. 12.17.2.4 Condition flags This instruction does not change the condition flags. 12.17.2.5 Examples CPSID CPSID CPSIE CPSIE i f i f ; ; ; ; Disable interrupts and configurable fault handlers (set PRIMASK) Disable interrupts and all fault handlers (set FAULTMASK) Enable interrupts and configurable fault handlers (clear PRIMASK) Enable interrupts and fault handlers (clear FAULTMASK) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 137 12.17.3 DMB Data Memory Barrier. 12.17.3.1 Syntax DMB{cond} where: cond is an optional condition code, see “Conditional execution” on page 87. 12.17.3.2 Operation DMB acts as a data memory barrier. It ensures that all explicit memory accesses that appear, in program order, before the DMB instruction are completed before any explicit memory accesses that appear, in program order, after the DMB instruction. DMB does not affect the ordering or execution of instructions that do not access memory. 12.17.3.3 Condition flags This instruction does not change the flags. 12.17.3.4 Examples DMB 138 ; Data Memory Barrier SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.17.4 DSB Data Synchronization Barrier. 12.17.4.1 Syntax DSB{cond} where: cond is an optional condition code, see “Conditional execution” on page 87. 12.17.4.2 Operation DSB acts as a special data synchronization memory barrier. Instructions that come after the DSB, in program order, do not execute until the DSB instruction completes. The DSB instruction completes when all explicit memory accesses before it complete. 12.17.4.3 Condition flags This instruction does not change the flags. 12.17.4.4 Examples DSB ; Data Synchronisation Barrier SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 139 12.17.5 ISB Instruction Synchronization Barrier. 12.17.5.1 Syntax ISB{cond} where: cond is an optional condition code, see “Conditional execution” on page 87. 12.17.5.2 Operation ISB acts as an instruction synchronization barrier. It flushes the pipeline of the processor, so that all instructions following the ISB are fetched from memory again, after the ISB instruction has been completed. 12.17.5.3 Condition flags This instruction does not change the flags. 12.17.5.4 Examples ISB 140 ; Instruction Synchronisation Barrier SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.17.6 MRS Move the contents of a special register to a general-purpose register. 12.17.6.1 Syntax MRS{cond} Rd, spec_reg where: cond is an optional condition code, see “Conditional execution” on page 87. Rd is the destination register. spec_reg can be any of: APSR, IPSR, EPSR, IEPSR, IAPSR, EAPSR, PSR, MSP, PSP, PRIMASK, BASEPRI, BASEPRI_MAX, FAULTMASK, or CONTROL. 12.17.6.2 Operation Use MRS in combination with MSR as part of a read-modify-write sequence for updating a PSR, for example to clear the Q flag. In process swap code, the programmers model state of the process being swapped out must be saved, including relevant PSR contents. Similarly, the state of the process being swapped in must also be restored. These operations use MRS in the state-saving instruction sequence and MSR in the state-restoring instruction sequence. BASEPRI_MAX is an alias of BASEPRI when used with the MRS instruction. See “MSR” on page 142. 12.17.6.3 Restrictions Rd must not be SP and must not be PC. 12.17.6.4 Condition flags This instruction does not change the flags. 12.17.6.5 Examples MRS R0, PRIMASK ; Read PRIMASK value and write it to R0 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 141 12.17.7 MSR Move the contents of a general-purpose register into the specified special register. 12.17.7.1 Syntax MSR{cond} spec_reg, Rn where: cond is an optional condition code, see “Conditional execution” on page 87. Rn is the source register. spec_reg can be any of: APSR, IPSR, EPSR, IEPSR, IAPSR, EAPSR, PSR, MSP, PSP, PRIMASK, BASEPRI, BASEPRI_MAX, FAULTMASK, or CONTROL. 12.17.7.2 Operation The register access operation in MSR depends on the privilege level. Unprivileged software can only access the APSR, see “Application Program Status Register” on page 50. Privileged software can access all special registers. In unprivileged software writes to unallocated or execution state bits in the PSR are ignored. When you write to BASEPRI_MAX, the instruction writes to BASEPRI only if either:  Rn is non-zero and the current BASEPRI value is 0  Rn is non-zero and less than the current BASEPRI value. See “MRS” on page 141. 12.17.7.3 Restrictions Rn must not be SP and must not be PC. 12.17.7.4 Condition flags This instruction updates the flags explicitly based on the value in Rn. 12.17.7.5 Examples MSR 142 CONTROL, R1 ; Read R1 value and write it to the CONTROL register SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.17.8 NOP No Operation. 12.17.8.1 Syntax NOP{cond} where: cond is an optional condition code, see “Conditional execution” on page 87. 12.17.8.2 Operation NOP does nothing. NOP is not necessarily a time-consuming NOP. The processor might remove it from the pipeline before it reaches the execution stage. Use NOP for padding, for example to place the following instruction on a 64-bit boundary. 12.17.8.3 Condition flags This instruction does not change the flags. 12.17.8.4 Examples NOP ; No operation SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 143 12.17.9 SEV Send Event. 12.17.9.1 Syntax SEV{cond} where: cond is an optional condition code, see “Conditional execution” on page 87. 12.17.9.2 Operation SEV is a hint instruction that causes an event to be signaled to all processors within a multiprocessor system. It also sets the local event register to 1, see “Power management” on page 76. 12.17.9.3 Condition flags This instruction does not change the flags. 12.17.9.4 Examples SEV ; Send Event 144 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.17.10SVC Supervisor Call. 12.17.10.1 Syntax SVC{cond} #imm where: cond is an optional condition code, see “Conditional execution” on page 87. imm is an expression evaluating to an integer in the range 0-255 (8-bit value). 12.17.10.2 Operation The SVC instruction causes the SVC exception. imm is ignored by the processor. If required, it can be retrieved by the exception handler to determine what service is being requested. 12.17.10.3 Condition flags This instruction does not change the flags. 12.17.10.4 Examples SVC 0x32 ; Supervisor Call (SVC handler can extract the immediate value ; by locating it via the stacked PC) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 145 12.17.11WFE Wait For Event. 12.17.11.1 Syntax WFE{cond} where: cond is an optional condition code, see “Conditional execution” on page 87. 12.17.11.2 Operation WFE is a hint instruction. If the event register is 0, WFE suspends execution until one of the following events occurs:  an exception, unless masked by the exception mask registers or the current priority level  an exception enters the Pending state, if SEVONPEND in the System Control Register is set  a Debug Entry request, if Debug is enabled  an event signaled by a peripheral or another processor in a multiprocessor system using the SEV instruction. If the event register is 1, WFE clears it to 0 and returns immediately. For more information see “Power management” on page 76. 12.17.11.3 Condition flags This instruction does not change the flags. 12.17.11.4 Examples WFE 146 ; Wait for event SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.17.12WFI Wait for Interrupt. 12.17.12.1 Syntax WFI{cond} where: cond is an optional condition code, see “Conditional execution” on page 87. 12.17.12.2 Operation WFI is a hint instruction that suspends execution until one of the following events occurs:  an exception  a Debug Entry request, regardless of whether Debug is enabled. 12.17.12.3 Condition flags This instruction does not change the flags. 12.17.12.4 Examples WFI ; Wait for interrupt SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 147 12.18 About the Cortex-M3 peripherals The address map of the Private peripheral bus (PPB) is: Table 12-26. Core peripheral register regions Address Core peripheral Description 0xE000E0080xE000E00F System control block Table 12-30 on page 161 0xE000E0100xE000E01F System timer Table 12-33 on page 189 0xE000E1000xE000E4EF Nested Vectored Interrupt Controller Table 12-27 on page 149 0xE000ED000xE000ED3F System control block Table 12-30 on page 161 0xE000ED900xE000EDB8 Memory protection unit Table 12-35 on page 195 0xE000EF000xE000EF03 Nested Vectored Interrupt Controller Table 12-27 on page 149 In register descriptions:   148 the register type is described as follows: RW Read and write. RO Read-only. WO Write-only. the required privilege gives the privilege level required to access the register, as follows: Privileged Only privileged software can access the register. Unprivileged Both unprivileged and privileged software can access the register. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.19 Nested Vectored Interrupt Controller This section describes the Nested Vectored Interrupt Controller (NVIC) and the registers it uses. The NVIC supports:  1 to 30 interrupts.  A programmable priority level of 0-15 for each interrupt. A higher level corresponds to a lower priority, so level 0 is the highest interrupt priority.  Level detection of interrupt signals.  Dynamic reprioritization of interrupts.  Grouping of priority values into group priority and subpriority fields.  Interrupt tail-chaining. The processor automatically stacks its state on exception entry and unstacks this state on exception exit, with no instruction overhead. This provides low latency exception handling. The hardware implementation of the NVIC registers is: Table 12-27. NVIC register summary Address Name Type Required privilege Reset value Description 0xE000E100 ISER0 RW Privileged 0x00000000 “Interrupt Set-enable Registers” on page 151 0xE000E180 ICER0 RW Privileged 0x00000000 “Interrupt Clear-enable Registers” on page 152 0xE000E200 ISPR0 RW Privileged 0x00000000 “Interrupt Set-pending Registers” on page 153 0xE000E280 ICPR0 RW Privileged 0x00000000 “Interrupt Clear-pending Registers” on page 154 0xE000E300 IABR0 RO Privileged 0x00000000 “Interrupt Active Bit Registers” on page 155 0xE000E400- IPR0- 0xE000E41C IPR7 RW Privileged 0x00000000 “Interrupt Priority Registers” on page 156 0xE000EF00 STIR WO Configurable (1) 0x00000000 “Software Trigger Interrupt Register” on page 158 1. See the register description for more information. 12.19.1 The CMSIS mapping of the Cortex-M3 NVIC registers To improve software efficiency, the CMSIS simplifies the NVIC register presentation. In the CMSIS:  the Set-enable, Clear-enable, Set-pending, Clear-pending and Active Bit registers map to arrays of 32-bit integers, so that: ̶ ̶ ̶ the array ISPR[0] corresponds to the registers ISPR0 ̶ the array ICPR[0] corresponds to the registers ICPR0 ̶  the array ISER[0] corresponds to the registers ISER0 the array ICER[0] corresponds to the registers ICER0 the array IABR[0] corresponds to the registers IABR0 the 4-bit fields of the Interrupt Priority Registers map to an array of 4-bit integers, so that the array IP[0] to IP[29] corresponds to the registers IPR0-IPR7, and the array entry IP[n] holds the interrupt priority for interrupt n. The CMSIS provides thread-safe code that gives atomic access to the Interrupt Priority Registers. For more information see the description of the NVIC_SetPriority function in “NVIC programming hints” on page 159. Table 12-28 shows how the interrupts, or IRQ numbers, map onto the interrupt registers and corresponding CMSIS variables that have one bit per interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 149 Table 12-28. Mapping of interrupts to the interrupt variables CMSIS array elements (1) Interrupts Set-enable Clear-enable Set-pending Clear-pending Active Bit 0-29 ISER[0] ICER[0] ISPR[0] ICPR[0] IABR[0] 1. 150 Each array element corresponds to a single NVIC register, for example the element ICER[0] corresponds to the ICER0 register. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.19.2 Interrupt Set-enable Registers The ISER0 register enables interrupts, and show which interrupts are enabled. See:  the register summary in Table 12-27 on page 149 for the register attributes  Table 12-28 on page 150 for which interrupts are controlled by each register. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 SETENA bits 23 22 21 20 SETENA bits 15 14 13 12 SETENA bits 7 6 5 4 SETENA bits • SETENA Interrupt set-enable bits. Write: 0 = no effect 1 = enable interrupt. Read: 0 = interrupt disabled 1 = interrupt enabled. If a pending interrupt is enabled, the NVIC activates the interrupt based on its priority. If an interrupt is not enabled, asserting its interrupt signal changes the interrupt state to pending, but the NVIC never activates the interrupt, regardless of its priority. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 151 12.19.3 Interrupt Clear-enable Registers The ICER0 register disables interrupts, and shows which interrupts are enabled. See:  the register summary in Table 12-27 on page 149 for the register attributes  Table 12-28 on page 150 for which interrupts are controlled by each register The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 CLRENA 23 22 21 20 CLRENA 15 14 13 12 CLRENA 7 6 5 4 CLRENA • CLRENA Interrupt clear-enable bits. Write: 0 = no effect 1 = disable interrupt. Read: 0 = interrupt disabled 1 = interrupt enabled. 152 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.19.4 Interrupt Set-pending Registers The ISPR0 register forces interrupts into the pending state, and shows which interrupts are pending. See:  the register summary in Table 12-27 on page 149 for the register attributes  Table 12-28 on page 150 for which interrupts are controlled by each register. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 SETPEND 23 22 21 20 SETPEND 15 14 13 12 SETPEND 7 6 5 4 SETPEND • SETPEND Interrupt set-pending bits. Write: 0 = no effect. 1 = changes interrupt state to pending. Read: 0 = interrupt is not pending. 1 = interrupt is pending. Writing 1 to the ISPR bit corresponding to: • an interrupt that is pending has no effect • a disabled interrupt sets the state of that interrupt to pending SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 153 12.19.5 Interrupt Clear-pending Registers The ICPR0 register removes the pending state from interrupts, and show which interrupts are pending. See:  the register summary in Table 12-27 on page 149 for the register attributes  Table 12-28 on page 150 for which interrupts are controlled by each register. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 CLRPEND 23 22 21 20 CLRPEND 15 14 13 12 CLRPEND 7 6 5 4 CLRPEND • CLRPEND Interrupt clear-pending bits. Write: 0 = no effect. 1 = removes pending state an interrupt. Read: 0 = interrupt is not pending. 1 = interrupt is pending. Writing 1 to an ICPR bit does not affect the active state of the corresponding interrupt. 154 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.19.6 Interrupt Active Bit Registers The IABR0 register indicates which interrupts are active. See:  the register summary in Table 12-27 on page 149 for the register attributes  Table 12-28 on page 150 for which interrupts are controlled by each register. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 ACTIVE 23 22 21 20 ACTIVE 15 14 13 12 ACTIVE 7 6 5 4 ACTIVE • ACTIVE Interrupt active flags: 0 = interrupt not active 1 = interrupt active. A bit reads as one if the status of the corresponding interrupt is active or active and pending. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 155 12.19.7 Interrupt Priority Registers The IPR0-IPR7 registers provide a 4-bit priority field for each interrupt (See the “Peripheral Identifiers” section of the datasheet for more details). These registers are byte-accessible. See the register summary in Table 12-27 on page 149 for their attributes. Each register holds four priority fields, that map up to four elements in the CMSIS interrupt priority array IP[0] to IP[29], as shown: 12.19.7.1 IPRm 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 IP[4m+3] 23 22 21 20 IP[4m+2] 15 14 13 12 IP[4m+1] 7 6 5 4 IP[4m] 12.19.7.2 IPR4 31 30 29 28 IP[19] 23 22 21 20 IP[18] 15 14 13 12 IP[17] 7 6 5 4 IP[16] 12.19.7.3 IPR3 31 30 29 28 IP[15] 23 22 21 20 IP[14] 15 14 13 12 IP[13] 7 6 5 4 IP[12] 12.19.7.4 IPR2 31 30 29 28 IP[11] 23 22 21 20 IP[10] 15 14 13 12 IP[9] 7 6 5 4 IP[8] 156 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.19.7.5 IPR1 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 IP[7] 23 22 21 20 IP[6] 15 14 13 12 IP[5] 7 6 5 4 IP[4] 12.19.7.6 IPR0 31 30 29 28 IP[3] 23 22 21 20 IP[2] 15 14 13 12 IP[1] 7 6 5 4 IP[0] • Priority, byte offset 3 • Priority, byte offset 2 • Priority, byte offset 1 • Priority, byte offset 0 Each priority field holds a priority value, 0-15. The lower the value, the greater the priority of the corresponding interrupt. The processor implements only bits[7:4] of each field, bits[3:0] read as zero and ignore writes. See “The CMSIS mapping of the Cortex-M3 NVIC registers” on page 149 for more information about the IP[0] to IP[29] interrupt priority array, that provides the software view of the interrupt priorities. Find the IPR number and byte offset for interrupt N as follows: • the corresponding IPR number, M, is given by M = N DIV 4 • the byte offset of the required Priority field in this register is N MOD 4, where: – byte offset 0 refers to register bits[7:0] – byte offset 1 refers to register bits[15:8] – byte offset 2 refers to register bits[23:16] – byte offset 3 refers to register bits[31:24]. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 157 12.19.8 Software Trigger Interrupt Register Write to the STIR to generate a Software Generated Interrupt (SGI). See the register summary in Table 12-27 on page 149 for the STIR attributes. When the USERSETMPEND bit in the SCR is set to 1, unprivileged software can access the STIR, see “System Control Register” on page 170. Only privileged software can enable unprivileged access to the STIR. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 8 INTID 4 3 2 1 INTID • INTID Interrupt ID of the required SGI, in the range 0-239. For example, a value of b000000011 specifies interrupt IRQ3. 158 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 0 12.19.9 Level-sensitive interrupts The processor supports level-sensitive interrupts. A level-sensitive interrupt is held asserted until the peripheral deasserts the interrupt signal. Typically this happens because the ISR accesses the peripheral, causing it to clear the interrupt request. When the processor enters the ISR, it automatically removes the pending state from the interrupt, see “Hardware and software control of interrupts”. For a level-sensitive interrupt, if the signal is not deasserted before the processor returns from the ISR, the interrupt becomes pending again, and the processor must execute its ISR again. This means that the peripheral can hold the interrupt signal asserted until it no longer needs servicing. 12.19.9.1 Hardware and software control of interrupts The Cortex-M3 latches all interrupts. A peripheral interrupt becomes pending for one of the following reasons:  the NVIC detects that the interrupt signal is HIGH and the interrupt is not active  the NVIC detects a rising edge on the interrupt signal  software writes to the corresponding interrupt set-pending register bit, see “Interrupt Set-pending Registers” on page 153, or to the STIR to make an SGI pending, see “Software Trigger Interrupt Register” on page 158. A pending interrupt remains pending until one of the following: The processor enters the ISR for the interrupt. This changes the state of the interrupt from pending to active. Then: ̶ ̶  For a level-sensitive interrupt, when the processor returns from the ISR, the NVIC samples the interrupt signal. If the signal is asserted, the state of the interrupt changes to pending, which might cause the processor to immediately re-enter the ISR. Otherwise, the state of the interrupt changes to inactive. If the interrupt signal is not pulsed while the processor is in the ISR, when the processor returns from the ISR the state of the interrupt changes to inactive. Software writes to the corresponding interrupt clear-pending register bit. For a level-sensitive interrupt, if the interrupt signal is still asserted, the state of the interrupt does not change. Otherwise, the state of the interrupt changes to inactive. 12.19.10NVIC design hints and tips Ensure software uses correctly aligned register accesses. The processor does not support unaligned accesses to NVIC registers. See the individual register descriptions for the supported access sizes. A interrupt can enter pending state even it is disabled. Before programming VTOR to relocate the vector table, ensure the vector table entries of the new vector table are setup for fault handlers and all enabled exception like interrupts. For more information see “Vector Table Offset Register” on page 167. 12.19.10.1 NVIC programming hints Software uses the CPSIE I and CPSID I instructions to enable and disable interrupts. The CMSIS provides the following intrinsic functions for these instructions: void __disable_irq(void) // Disable Interrupts void __enable_irq(void) // Enable Interrupts SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 159 In addition, the CMSIS provides a number of functions for NVIC control, including: Table 12-29. CMSIS functions for NVIC control CMSIS interrupt control function Description void NVIC_SetPriorityGrouping(uint32_t priority_grouping) Set the priority grouping void NVIC_EnableIRQ(IRQn_t IRQn) Enable IRQn void NVIC_DisableIRQ(IRQn_t IRQn) Disable IRQn uint32_t NVIC_GetPendingIRQ (IRQn_t IRQn) Return true if IRQn is pending void NVIC_SetPendingIRQ (IRQn_t IRQn) Set IRQn pending void NVIC_ClearPendingIRQ (IRQn_t IRQn) Clear IRQn pending status uint32_t NVIC_GetActive (IRQn_t IRQn) Return the IRQ number of the active interrupt void NVIC_SetPriority (IRQn_t IRQn, uint32_t priority) Set priority for IRQn uint32_t NVIC_GetPriority (IRQn_t IRQn) Read priority of IRQn void NVIC_SystemReset (void) Reset the system For more information about these functions see the CMSIS documentation. 160 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20 System control block The System control block (SCB) provides system implementation information, and system control. This includes configuration, control, and reporting of the system exceptions. The system control block registers are: Table 12-30. Summary of the system control block registers Address Name Type Required privilege Reset value Description 0xE000E008 ACTLR RW Privileged 0x00000000 “Auxiliary Control Register” on page 162 0xE000ED00 CPUID RO Privileged 0x412FC230 “CPUID Base Register” on page 163 Privileged 0x00000000 “Interrupt Control and State Register” on page 164 Privileged 0x00000000 “Vector Table Offset Register” on page 167 Privileged 0xFA050000 “Application Interrupt and Reset Control Register” on page 168 0xE000ED04 ICSR RW 0xE000ED08 VTOR RW (1) (1) 0xE000ED0C AIRCR RW 0xE000ED10 SCR RW Privileged 0x00000000 “System Control Register” on page 170 0xE000ED14 CCR RW Privileged 0x00000200 “Configuration and Control Register” on page 171 0xE000ED18 SHPR1 RW Privileged 0x00000000 “System Handler Priority Register 1” on page 174 0xE000ED1C SHPR2 RW Privileged 0x00000000 “System Handler Priority Register 2” on page 175 0xE000ED20 SHPR3 RW Privileged 0x00000000 “System Handler Priority Register 3” on page 176 0xE000ED24 SHCRS RW Privileged 0x00000000 “System Handler Control and State Register” on page 177 0xE000ED28 CFSR RW Privileged 0x00000000 “Configurable Fault Status Register” on page 179 (2) RW Privileged 0x00 “Memory Management Fault Address Register” on page 186 BFSR (2) RW Privileged 0x00 “Bus Fault Status Register” on page 181 0xE000ED2A UFSR (2) RW Privileged 0x0000 “Usage Fault Status Register” on page 183 0xE000ED2C HFSR RW Privileged 0x00000000 “Hard Fault Status Register” on page 185 0xE000ED34 MMAR RW Privileged Unknown “Memory Management Fault Address Register” on page 186 0xE000ED38 BFAR RW Privileged Unknown “Bus Fault Address Register” on page 187 0xE000ED3C AFSR RW Privileged 0x00000000 “Auxiliary Fault Status Register” on page 188 0xE000ED28 0xE000ED29 Notes: MMSR 1. See the register description for more information. 2. A subregister of the CFSR. 12.20.1 The CMSIS mapping of the Cortex-M3 SCB registers To improve software efficiency, the CMSIS simplifies the SCB register presentation. In the CMSIS, the byte array SHP[0] to SHP[12] corresponds to the registers SHPR1-SHPR3. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 161 12.20.2 Auxiliary Control Register The ACTLR provides disable bits for the following processor functions:  IT folding  write buffer use for accesses to the default memory map  interruption of multi-cycle instructions. See the register summary in Table 12-30 on page 161 for the ACTLR attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 DISFOLD 1 DISDEFWBUF 0 DISMCYCINT Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 Reserved 4 • DISFOLD When set to 1, disables IT folding. see “About IT folding” on page 162 for more information. • DISDEFWBUF When set to 1, disables write buffer use during default memory map accesses. This causes all bus faults to be precise bus faults but decreases performance because any store to memory must complete before the processor can execute the next instruction. This bit only affects write buffers implemented in the Cortex-M3 processor. • DISMCYCINT When set to 1, disables interruption of load multiple and store multiple instructions. This increases the interrupt latency of the processor because any LDM or STM must complete before the processor can stack the current state and enter the interrupt handler. 12.20.2.1 About IT folding In some situations, the processor can start executing the first instruction in an IT block while it is still executing the IT instruction. This behavior is called IT folding, and improves performance, However, IT folding can cause jitter in looping. If a task must avoid jitter, set the DISFOLD bit to 1 before executing the task, to disable IT folding. 162 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.3 CPUID Base Register The CPUID register contains the processor part number, version, and implementation information. See the register summary in Table 12-30 on page 161 for its attributes. The bit assignments are: 31 30 29 28 27 26 19 18 25 24 17 16 9 8 1 0 Implementer 23 22 21 20 Variant 15 14 Constant 13 12 11 10 3 2 PartNo 7 6 5 4 PartNo Revision • Implementer Implementer code: 0x41 = ARM • Variant Variant number, the r value in the rnpn product revision identifier: 0x2 = r2p0 • Constant Reads as 0xF • PartNo Part number of the processor: 0xC23 = Cortex-M3 • Revision Revision number, the p value in the rnpn product revision identifier: 0x0 = r2p0 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 163 12.20.4 Interrupt Control and State Register The ICSR:  provides: ̶  set-pending and clear-pending bits for the PendSV and SysTick exceptions indicates: ̶ the exception number of the exception being processed ̶ whether there are preempted active exceptions ̶ the exception number of the highest priority pending exception ̶ whether any interrupts are pending. See the register summary in Table 12-30 on page 161, and the Type descriptions in Table 12-33 on page 189, for the ICSR attributes. The bit assignments are: 31 30 Reserved 29 Reserved 23 22 Reserved for Debug ISRPENDING 15 14 28 27 26 25 24 PENDSVSET PENDSVCLR PENDSTSET PENDSTCLR Reserved 20 19 18 17 16 21 VECTPENDING 13 12 11 VECTPENDING 7 6 5 4 3 VECTACTIVE • PENDSVSET RW PendSV set-pending bit. Write: 0 = no effect 1 = changes PendSV exception state to pending. Read: 0 = PendSV exception is not pending 1 = PendSV exception is pending. Writing 1 to this bit is the only way to set the PendSV exception state to pending. • PENDSVCLR WO PendSV clear-pending bit. Write: 0 = no effect 1 = removes the pending state from the PendSV exception. 164 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 10 RETTOBASE 9 Reserved 2 8 VECTACTIVE 1 0 • PENDSTSET RW SysTick exception set-pending bit. Write: 0 = no effect 1 = changes SysTick exception state to pending. Read: 0 = SysTick exception is not pending 1 = SysTick exception is pending. • PENDSTCLR WO SysTick exception clear-pending bit. Write: 0 = no effect 1 = removes the pending state from the SysTick exception. This bit is WO. On a register read its value is Unknown. • Reserved for Debug use RO This bit is reserved for Debug use and reads-as-zero when the processor is not in Debug. • ISRPENDING RO Interrupt pending flag, excluding Faults: 0 = interrupt not pending 1 = interrupt pending. • VECTPENDING RO Indicates the exception number of the highest priority pending enabled exception: 0 = no pending exceptions Nonzero = the exception number of the highest priority pending enabled exception. The value indicated by this field includes the effect of the BASEPRI and FAULTMASK registers, but not any effect of the PRIMASK register. • RETTOBASE RO Indicates whether there are preempted active exceptions: 0 = there are preempted active exceptions to execute 1 = there are no active exceptions, or the currently-executing exception is the only active exception. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 165 • VECTACTIVE RO Contains the active exception number: 0 = Thread mode Nonzero = The exception number (1) of the currently active exception. Subtract 16 from this value to obtain the IRQ number required to index into the Interrupt Clear-Enable, Set-Enable, ClearPending, Set-Pending, or Priority Registers, see “Interrupt Program Status Register” on page 51. When you write to the ICSR, the effect is Unpredictable if you: • write 1 to the PENDSVSET bit and write 1 to the PENDSVCLR bit • write 1 to the PENDSTSET bit and write 1 to the PENDSTCLR bit. Note: 166 1. This is the same value as IPSR bits [8:0] see “Interrupt Program Status Register” on page 51. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.5 Vector Table Offset Register The VTOR indicates the offset of the vector table base address from memory address 0x00000000. See the register summary in Table 12-30 on page 161 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 Reserved 23 TBLOFF 22 21 20 TBLOFF 15 14 13 12 TBLOFF 7 6 5 TBLOFF 4 Reserved • TBLOFF Vector table base offset field. It contains bits[29:7] of the offset of the table base from the bottom of the memory map. Bit[29] determines whether the vector table is in the code or SRAM memory region: 0 = code 1 = SRAM. Bit[29] is sometimes called the TBLBASE bit. When setting TBLOFF, you must align the offset to the number of exception entries in the vector table. The minimum alignment is 32 words, enough for up to 16 interrupts. For more interrupts, adjust the alignment by rounding up to the next power of two. For example, if you require 21 interrupts, the alignment must be on a 64-word boundary because the required table size is 37 words, and the next power of two is 64. Table alignment requirements mean that bits[6:0] of the table offset are always zero. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 167 12.20.6 Application Interrupt and Reset Control Register The AIRCR provides priority grouping control for the exception model, endian status for data accesses, and reset control of the system. See the register summary in Table 12-30 on page 161 and Table 12-33 on page 189 for its attributes. To write to this register, you must write 0x05FA to the VECTKEY field, otherwise the processor ignores the write. The bit assignments are: 31 30 29 28 27 26 25 24 18 17 16 9 8 On Read: VECTKEYSTAT, On Write: VECTKEY 23 22 21 20 19 On Read: VECTKEYSTAT, On Write: VECTKEY 15 14 13 ENDIANESS 7 12 11 6 5 PRIGROUP 4 3 Reserved • 10 Reserved 2 1 0 SYSRESETREQ VECTCLRACTIVE VECTRESET VECTKEYSTAT Register Key: Reads as 0xFA05 • VECTKEY Register key: On writes, write 0x5FA to VECTKEY, otherwise the write is ignored. • ENDIANESS RO Data endianness bit: 0 = Little-endian ENDIANESS is set from the BIGEND configuration signal during reset. • PRIGROUP R/W Interrupt priority grouping field. This field determines the split of group priority from subpriority, see “Binary point” on page 169. • SYSRESETREQ WO System reset request: 0 = no effect 1 = asserts a proc_reset_signal. This is intended to force a large system reset of all major components except for debug. This bit reads as 0. 168 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • VECTCLRACTIVE WO Reserved for Debug use. This bit reads as 0. When writing to the register you must write 0 to this bit, otherwise behavior is Unpredictable. • VECTRESET WO Reserved for Debug use. This bit reads as 0. When writing to the register you must write 0 to this bit, otherwise behavior is Unpredictable. 12.20.6.1 Binary point The PRIGROUP field indicates the position of the binary point that splits the PRI_n fields in the Interrupt Priority Registers into separate group priority and subpriority fields. Table 12-31 shows how the PRIGROUP value controls this split. Table 12-31. Priority grouping Interrupt priority level value, PRI_N[7:0] (1) Number of Group priority bits Subpriority bits Group priorities Subpriorities bxxxx.0000 [7:4] None 16 1 b100 bxxx.y0000 [7:5] [4] 8 2 b101 bxx.yy0000 [7:6] [5:4] 4 4 b110 bx.yyy0000 [7] [6:4] 2 8 b111 b.yyyy0000 None [7:4] 1 16 PRIGROUP Binary point b011 1. PRI_n[7:0] field showing the binary point. x denotes a group priority field bit, and y denotes a subpriority field bit. Determining preemption of an exception uses only the group priority field, see “Interrupt priority grouping” on page 71. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 169 12.20.7 System Control Register The SCR controls features of entry to and exit from low power state. See the register summary in Table 12-30 on page 161 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 Reserved 4 3 2 1 0 SEVONPEND Reserved SLEEPDEEP SLEEONEXIT Reserved • SEVONPEND Send Event on Pending bit: 0 = only enabled interrupts or events can wakeup the processor, disabled interrupts are excluded 1 = enabled events and all interrupts, including disabled interrupts, can wakeup the processor. When an event or interrupt enters pending state, the event signal wakes up the processor from WFE. If the processor is not waiting for an event, the event is registered and affects the next WFE. The processor also wakes up on execution of an SEV instruction or an external event. • SLEEPDEEP Controls whether the processor uses sleep or deep sleep as its low power mode: 0 = sleep 1 = deep sleep. • SLEEPONEXIT Indicates sleep-on-exit when returning from Handler mode to Thread mode: 0 = do not sleep when returning to Thread mode. 1 = enter sleep, or deep sleep, on return from an ISR. Setting this bit to 1 enables an interrupt driven application to avoid returning to an empty main application. 170 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.8 Configuration and Control Register The CCR controls entry to Thread mode and enables:  the handlers for hard fault and faults escalated by FAULTMASK to ignore bus faults  trapping of divide by zero and unaligned accesses  access to the STIR by unprivileged software, see “Software Trigger Interrupt Register” on page 158. See the register summary in Table 12-30 on page 161 for the CCR attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 Reserved 9 8 STKALIGN BFHFNMIGN 4 3 2 1 0 DIV_0_TRP UNALIGN_T RP Reserved USERSETM PEND NONBASET HRDENA • STKALIGN Indicates stack alignment on exception entry: 0 = 4-byte aligned 1 = 8-byte aligned. On exception entry, the processor uses bit[9] of the stacked PSR to indicate the stack alignment. On return from the exception it uses this stacked bit to restore the correct stack alignment. • BFHFNMIGN Enables handlers with priority -1 or -2 to ignore data bus faults caused by load and store instructions. This applies to the hard fault and FAULTMASK escalated handlers: 0 = data bus faults caused by load and store instructions cause a lock-up 1 = handlers running at priority -1 and -2 ignore data bus faults caused by load and store instructions. Set this bit to 1 only when the handler and its data are in absolutely safe memory. The normal use of this bit is to probe system devices and bridges to detect control path problems and fix them. • DIV_0_TRP Enables faulting or halting when the processor executes an SDIV or UDIV instruction with a divisor of 0: 0 = do not trap divide by 0 1 = trap divide by 0. When this bit is set to 0,a divide by zero returns a quotient of 0. • UNALIGN_TRP Enables unaligned access traps: 0 = do not trap unaligned halfword and word accesses 1 = trap unaligned halfword and word accesses. If this bit is set to 1, an unaligned access generates a usage fault. Unaligned LDM, STM, LDRD, and STRD instructions always fault irrespective of whether UNALIGN_TRP is set to 1. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 171 • USERSETMPEND Enables unprivileged software access to the STIR, see “Software Trigger Interrupt Register” on page 158: 0 = disable 1 = enable. • NONEBASETHRDENA Indicates how the processor enters Thread mode: 0 = processor can enter Thread mode only when no exception is active. 1 = processor can enter Thread mode from any level under the control of an EXC_RETURN value, see “Exception return” on page 72. 172 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.9 System Handler Priority Registers The SHPR1-SHPR3 registers set the priority level, 0 to 15 of the exception handlers that have configurable priority. SHPR1-SHPR3 are byte accessible. See the register summary in Table 12-30 on page 161 for their attributes. The system fault handlers and the priority field and register for each handler are: Table 12-32. System fault handler priority fields Handler Field Memory management fault PRI_4 Bus fault PRI_5 Usage fault PRI_6 SVCall PRI_11 PendSV PRI_14 SysTick PRI_15 Register description “System Handler Priority Register 1” on page 174 “System Handler Priority Register 2” on page 175 “System Handler Priority Register 3” on page 176 Each PRI_N field is 8 bits wide, but the processor implements only bits[7:4] of each field, and bits[3:0] read as zero and ignore writes. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 173 12.20.9.1 System Handler Priority Register 1 The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 PRI_7: Reserved 23 22 21 20 PRI_6 15 14 13 12 PRI_5 7 6 5 4 PRI_4 • PRI_7 Reserved • PRI_6 Priority of system handler 6, usage fault • PRI_5 Priority of system handler 5, bus fault • PRI_4 Priority of system handler 4, memory management fault 174 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.9.2 System Handler Priority Register 2 The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 PRI_11 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 4 Reserved • PRI_11 Priority of system handler 11, SVCall SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 175 12.20.9.3 System Handler Priority Register 3 The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 PRI_15 23 22 21 20 PRI_14 15 14 13 12 Reserved 7 6 5 4 Reserved • PRI_15 Priority of system handler 15, SysTick exception • PRI_14 Priority of system handler 14, PendSV 176 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.10System Handler Control and State Register The SHCSR enables the system handlers, and indicates:  the pending status of the bus fault, memory management fault, and SVC exceptions  the active status of the system handlers. See the register summary in Table 12-30 on page 161 for the SHCSR attributes. The bit assignments are: 31 30 29 28 27 26 25 24 Reserved 23 22 21 20 19 Reserved 18 17 16 USGFAULTENA BUSFAULTENA MEMFAULTENA 15 14 13 12 11 10 9 8 SVCALLPENDE D BUSFAULTPEND ED MEMFAULTPEN DED USGFAULTPEND ED SYSTICKACT PENDSVACT Reserved MONITORACT 7 6 5 4 SVCALLAVCT Reserved 3 2 1 0 USGFAULTACT Reserved BUSFAULTACT MEMFAULTACT • USGFAULTENA Usage fault enable bit, set to 1 to enable (1) • BUSFAULTENA Bus fault enable bit, set to 1 to enable (3) • MEMFAULTENA Memory management fault enable bit, set to 1 to enable (3) • SVCALLPENDED SVC call pending bit, reads as 1 if exception is pending (2) • BUSFAULTPENDED Bus fault exception pending bit, reads as 1 if exception is pending (2) • MEMFAULTPENDED Memory management fault exception pending bit, reads as 1 if exception is pending (2) • USGFAULTPENDED Usage fault exception pending bit, reads as 1 if exception is pending (2) • SYSTICKACT SysTick exception active bit, reads as 1 if exception is active (3) • PENDSVACT PendSV exception active bit, reads as 1 if exception is active 1. 2. 3. Enable bits, set to 1 to enable the exception, or set to 0 to disable the exception. Pending bits, read as 1 if the exception is pending, or as 0 if it is not pending. You can write to these bits to change the pending status of the exceptions. Active bits, read as 1 if the exception is active, or as 0 if it is not active. You can write to these bits to change the active status of the exceptions, but see the Caution in this section. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 177 • MONITORACT Debug monitor active bit, reads as 1 if Debug monitor is active • SVCALLACT SVC call active bit, reads as 1 if SVC call is active • USGFAULTACT Usage fault exception active bit, reads as 1 if exception is active • BUSFAULTACT Bus fault exception active bit, reads as 1 if exception is active • MEMFAULTACT Memory management fault exception active bit, reads as 1 if exception is active If you disable a system handler and the corresponding fault occurs, the processor treats the fault as a hard fault. You can write to this register to change the pending or active status of system exceptions. An OS kernel can write to the active bits to perform a context switch that changes the current exception type. • Software that changes the value of an active bit in this register without correct adjustment to the stacked content can cause the processor to generate a fault exception. Ensure software that writes to this register retains and subsequently restores the current active status. • After you have enabled the system handlers, if you have to change the value of a bit in this register you must use a read-modify-write procedure to ensure that you change only the required bit. 178 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.11Configurable Fault Status Register The CFSR indicates the cause of a memory management fault, bus fault, or usage fault. See the register summary in Table 12-30 on page 161 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 18 17 16 10 9 8 2 1 0 Usage Fault Status Register: UFSR 23 22 21 20 19 Usage Fault Status Register: UFSR 15 14 13 12 11 Bus Fault Status Register: BFSR 7 6 5 4 3 Memory Management Fault Status Register: MMFSR The following subsections describe the subregisters that make up the CFSR:  “Memory Management Fault Status Register” on page 180  “Bus Fault Status Register” on page 181  “Usage Fault Status Register” on page 183. The CFSR is byte accessible. You can access the CFSR or its subregisters as follows:  access the complete CFSR with a word access to 0xE000ED28  access the MMFSR with a byte access to 0xE000ED28  access the MMFSR and BFSR with a halfword access to 0xE000ED28  access the BFSR with a byte access to 0xE000ED29  access the UFSR with a halfword access to 0xE000ED2A. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 179 12.20.11.1 Memory Management Fault Status Register The flags in the MMFSR indicate the cause of memory access faults. The bit assignments are: 7 6 MMARVALID 5 Reserved 4 3 2 1 0 MSTKERR MUNSTKERR Reserved DACCVIOL IACCVIOL • MMARVALID Memory Management Fault Address Register (MMAR) valid flag: 0 = value in MMAR is not a valid fault address 1 = MMAR holds a valid fault address. If a memory management fault occurs and is escalated to a hard fault because of priority, the hard fault handler must set this bit to 0. This prevents problems on return to a stacked active memory management fault handler whose MMAR value has been overwritten. • MSTKERR Memory manager fault on stacking for exception entry: 0 = no stacking fault 1 = stacking for an exception entry has caused one or more access violations. When this bit is 1, the SP is still adjusted but the values in the context area on the stack might be incorrect. The processor has not written a fault address to the MMAR. • MUNSTKERR Memory manager fault on unstacking for a return from exception: 0 = no unstacking fault 1 = unstack for an exception return has caused one or more access violations. This fault is chained to the handler. This means that when this bit is 1, the original return stack is still present. The processor has not adjusted the SP from the failing return, and has not performed a new save. The processor has not written a fault address to the MMAR. • DACCVIOL Data access violation flag: 0 = no data access violation fault 1 = the processor attempted a load or store at a location that does not permit the operation. When this bit is 1, the PC value stacked for the exception return points to the faulting instruction. The processor has loaded the MMAR with the address of the attempted access. • IACCVIOL Instruction access violation flag: 0 = no instruction access violation fault 1 = the processor attempted an instruction fetch from a location that does not permit execution. This fault occurs on any access to an XN region, even when the MPU is disabled or not present. When this bit is 1, the PC value stacked for the exception return points to the faulting instruction. The processor has not written a fault address to the MMAR. 180 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.11.2 Bus Fault Status Register The flags in the BFSR indicate the cause of a bus access fault. The bit assignments are: 7 6 BFRVALID 5 Reserved 4 STKERR 3 2 1 0 UNSTKERR IMPRECISE RR PRECISERR IBUSERR • BFARVALID Bus Fault Address Register (BFAR) valid flag: 0 = value in BFAR is not a valid fault address 1 = BFAR holds a valid fault address. The processor sets this bit to 1 after a bus fault where the address is known. Other faults can set this bit to 0, such as a memory management fault occurring later. If a bus fault occurs and is escalated to a hard fault because of priority, the hard fault handler must set this bit to 0. This prevents problems if returning to a stacked active bus fault handler whose BFAR value has been overwritten. • STKERR Bus fault on stacking for exception entry: 0 = no stacking fault 1 = stacking for an exception entry has caused one or more bus faults. When the processor sets this bit to 1, the SP is still adjusted but the values in the context area on the stack might be incorrect. The processor does not write a fault address to the BFAR. • UNSTKERR Bus fault on unstacking for a return from exception: 0 = no unstacking fault 1 = unstack for an exception return has caused one or more bus faults. This fault is chained to the handler. This means that when the processor sets this bit to 1, the original return stack is still present. The processor does not adjust the SP from the failing return, does not performed a new save, and does not write a fault address to the BFAR. • IMPRECISERR Imprecise data bus error: 0 = no imprecise data bus error 1 = a data bus error has occurred, but the return address in the stack frame is not related to the instruction that caused the error. When the processor sets this bit to 1, it does not write a fault address to the BFAR. This is an asynchronous fault. Therefore, if it is detected when the priority of the current process is higher than the bus fault priority, the bus fault becomes pending and becomes active only when the processor returns from all higher priority processes. If a precise fault occurs before the processor enters the handler for the imprecise bus fault, the handler detects both IMPRECISERR set to 1 and one of the precise fault status bits set to 1. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 181 • PRECISERR Precise data bus error: 0 = no precise data bus error 1 = a data bus error has occurred, and the PC value stacked for the exception return points to the instruction that caused the fault. When the processor sets this bit is 1, it writes the faulting address to the BFAR. • IBUSERR Instruction bus error: 0 = no instruction bus error 1 = instruction bus error. The processor detects the instruction bus error on prefetching an instruction, but it sets the IBUSERR flag to 1 only if it attempts to issue the faulting instruction. When the processor sets this bit is 1, it does not write a fault address to the BFAR. 182 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.11.3 Usage Fault Status Register The UFSR indicates the cause of a usage fault. The bit assignments are: 15 14 13 12 11 10 Reserved 7 6 5 4 Reserved 9 8 DIVBYZERO UNALIGNED 3 2 1 0 NOCP INVPC INVSTATE UNDEFINSTR • DIVBYZERO Divide by zero usage fault: 0 = no divide by zero fault, or divide by zero trapping not enabled 1 = the processor has executed an SDIV or UDIV instruction with a divisor of 0. When the processor sets this bit to 1, the PC value stacked for the exception return points to the instruction that performed the divide by zero. Enable trapping of divide by zero by setting the DIV_0_TRP bit in the CCR to 1, see “Configuration and Control Register” on page 171. • UNALIGNED Unaligned access usage fault: 0 = no unaligned access fault, or unaligned access trapping not enabled 1 = the processor has made an unaligned memory access. Enable trapping of unaligned accesses by setting the UNALIGN_TRP bit in the CCR to 1, see “Configuration and Control Register” on page 171. Unaligned LDM, STM, LDRD, and STRD instructions always fault irrespective of the setting of UNALIGN_TRP. • NOCP No coprocessor usage fault. The processor does not support coprocessor instructions: 0 = no usage fault caused by attempting to access a coprocessor 1 = the processor has attempted to access a coprocessor. • INVPC Invalid PC load usage fault, caused by an invalid PC load by EXC_RETURN: 0 = no invalid PC load usage fault 1 = the processor has attempted an illegal load of EXC_RETURN to the PC, as a result of an invalid context, or an invalid EXC_RETURN value. When this bit is set to 1, the PC value stacked for the exception return points to the instruction that tried to perform the illegal load of the PC. • INVSTATE Invalid state usage fault: 0 = no invalid state usage fault 1 = the processor has attempted to execute an instruction that makes illegal use of the EPSR. When this bit is set to 1, the PC value stacked for the exception return points to the instruction that attempted the illegal use of the EPSR. This bit is not set to 1 if an undefined instruction uses the EPSR. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 183 • UNDEFINSTR Undefined instruction usage fault: 0 = no undefined instruction usage fault 1 = the processor has attempted to execute an undefined instruction. When this bit is set to 1, the PC value stacked for the exception return points to the undefined instruction. An undefined instruction is an instruction that the processor cannot decode. The UFSR bits are sticky. This means as one or more fault occurs, the associated bits are set to 1. A bit that is set to 1 is cleared to 0 only by writing 1 to that bit, or by a reset. 184 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.12Hard Fault Status Register The HFSR gives information about events that activate the hard fault handler. See the register summary in Table 12-30 on page 161 for its attributes. This register is read, write to clear. This means that bits in the register read normally, but writing 1 to any bit clears that bit to 0. The bit assignments are: 31 30 DEBUGEVT FORCED 23 22 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 Reserved 21 20 Reserved 15 14 13 12 Reserved 7 6 5 4 Reserved 1 0 VECTTBL Reserved • DEBUGEVT Reserved for Debug use. When writing to the register you must write 0 to this bit, otherwise behavior is Unpredictable. • FORCED Indicates a forced hard fault, generated by escalation of a fault with configurable priority that cannot be handles, either because of priority or because it is disabled: 0 = no forced hard fault 1 = forced hard fault. When this bit is set to 1, the hard fault handler must read the other fault status registers to find the cause of the fault. • VECTTBL Indicates a bus fault on a vector table read during exception processing: 0 = no bus fault on vector table read 1 = bus fault on vector table read. This error is always handled by the hard fault handler. When this bit is set to 1, the PC value stacked for the exception return points to the instruction that was preempted by the exception. The HFSR bits are sticky. This means as one or more fault occurs, the associated bits are set to 1. A bit that is set to 1 is cleared to 0 only by writing 1 to that bit, or by a reset. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 185 12.20.13Memory Management Fault Address Register The MMFAR contains the address of the location that generated a memory management fault. See the register summary in Table 12-30 on page 161 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 ADDRESS 23 22 21 20 ADDRESS 15 14 13 12 ADDRESS 7 6 5 4 ADDRESS • ADDRESS When the MMARVALID bit of the MMFSR is set to 1, this field holds the address of the location that generated the memory management fault When an unaligned access faults, the address is the actual address that faulted. Because a single read or write instruction can be split into multiple aligned accesses, the fault address can be any address in the range of the requested access size. Flags in the MMFSR indicate the cause of the fault, and whether the value in the MMFAR is valid. See “Memory Management Fault Status Register” on page 180. 186 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.20.14Bus Fault Address Register The BFAR contains the address of the location that generated a bus fault. See the register summary in Table 1230 on page 161 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 ADDRESS 23 22 21 20 ADDRESS 15 14 13 12 ADDRESS 7 6 5 4 ADDRESS • ADDRESS When the BFARVALID bit of the BFSR is set to 1, this field holds the address of the location that generated the bus fault When an unaligned access faults the address in the BFAR is the one requested by the instruction, even if it is not the address of the fault. Flags in the BFSR indicate the cause of the fault, and whether the value in the BFAR is valid. See “Bus Fault Status Register” on page 181. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 187 12.20.15Auxiliary Fault Status Register The AFSR contains additional system fault information. See the register summary in Table 12-30 on page 161 for its attributes. This register is read, write to clear. This means that bits in the register read normally, but writing 1 to any bit clears that bit to 0. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 IMPDEF 23 22 21 20 IMPDEF 15 14 13 12 IMPDEF 7 6 5 4 IMPDEF • IMPDEF Implementation defined. The bits map to the AUXFAULT input signals. Each AFSR bit maps directly to an AUXFAULT input of the processor, and a single-cycle HIGH signal on the input sets the corresponding AFSR bit to one. It remains set to 1 until you write 1 to the bit to clear it to zero. When an AFSR bit is latched as one, an exception does not occur. Use an interrupt if an exception is required. 12.20.16System control block design hints and tips Ensure software uses aligned accesses of the correct size to access the system control block registers:  except for the CFSR and SHPR1-SHPR3, it must use aligned word accesses  for the CFSR and SHPR1-SHPR3 it can use byte or aligned halfword or word accesses. The processor does not support unaligned accesses to system control block registers. In a fault handler. to determine the true faulting address:  Read and save the MMFAR or BFAR value.  Read the MMARVALID bit in the MMFSR, or the BFARVALID bit in the BFSR. The MMFAR or BFAR address is valid only if this bit is 1. Software must follow this sequence because another higher priority exception might change the MMFAR or BFAR value. For example, if a higher priority handler preempts the current fault handler, the other fault might change the MMFAR or BFAR value. 188 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.21 System timer, SysTick The processor has a 24-bit system timer, SysTick, that counts down from the reload value to zero, reloads (wraps to) the value in the LOAD register on the next clock edge, then counts down on subsequent clocks. When the processor is halted for debugging the counter does not decrement. The system timer registers are: Table 12-33. System timer registers summary Address Name Type Required privilege Reset value Description 0xE000E010 CTRL RW Privileged 0x00000004 “SysTick Control and Status Register” on page 190 0xE000E014 LOAD RW Privileged 0x00000000 “SysTick Reload Value Register” on page 191 0xE000E018 VAL RW Privileged 0x00000000 “SysTick Current Value Register” on page 192 0xE000E01C 1. CALIB RO Privileged 0x0002904 (1) “SysTick Calibration Value Register” on page 193 SysTick calibration value. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 189 12.21.1 SysTick Control and Status Register The SysTick CTRL register enables the SysTick features. See the register summary in Table 12-33 on page 189 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 19 18 17 24 Reserved 23 22 21 20 Reserved 15 14 13 12 16 COUNTFLAG 11 10 9 8 Reserved 7 6 5 4 3 Reserved 2 1 0 CLKSOURCE TICKINT ENABLE • COUNTFLAG Returns 1 if timer counted to 0 since last time this was read. • CLKSOURCE Indicates the clock source: 0 = MCK/8 1 = MCK • TICKINT Enables SysTick exception request: 0 = counting down to zero does not assert the SysTick exception request 1 = counting down to zero to asserts the SysTick exception request. Software can use COUNTFLAG to determine if SysTick has ever counted to zero. • ENABLE Enables the counter: 0 = counter disabled 1 = counter enabled. When ENABLE is set to 1, the counter loads the RELOAD value from the LOAD register and then counts down. On reaching 0, it sets the COUNTFLAG to 1 and optionally asserts the SysTick depending on the value of TICKINT. It then loads the RELOAD value again, and begins counting. 190 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.21.2 SysTick Reload Value Register The LOAD register specifies the start value to load into the VAL register. See the register summary in Table 12-33 on page 189 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 Reserved 23 22 21 20 RELOAD 15 14 13 12 RELOAD 7 6 5 4 -RELOAD • RELOAD Value to load into the VAL register when the counter is enabled and when it reaches 0, see “Calculating the RELOAD value”. 12.21.2.1 Calculating the RELOAD value The RELOAD value can be any value in the range 0x00000001-0x00FFFFFF. A start value of 0 is possible, but has no effect because the SysTick exception request and COUNTFLAG are activated when counting from 1 to 0. The RELOAD value is calculated according to its use:  To generate a multi-shot timer with a period of N processor clock cycles, use a RELOAD value of N-1. For example, if the SysTick interrupt is required every 100 clock pulses, set RELOAD to 99.  To deliver a single SysTick interrupt after a delay of N processor clock cycles, use a RELOAD of value N. For example, if a SysTick interrupt is required after 400 clock pulses, set RELOAD to 400. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 191 12.21.3 SysTick Current Value Register The VAL register contains the current value of the SysTick counter. See the register summary in Table 12-33 on page 189 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 Reserved 23 22 21 20 CURRENT 15 14 13 12 CURRENT 7 6 5 4 CURRENT • CURRENT Reads return the current value of the SysTick counter. A write of any value clears the field to 0, and also clears the SysTick CTRL.COUNTFLAG bit to 0. 192 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.21.4 SysTick Calibration Value Register The CALIB register indicates the SysTick calibration properties. See the register summary in Table 12-33 on page 189 for its attributes. The bit assignments are: 31 30 NOREF SKEW 23 22 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 Reserved 21 20 TENMS 15 14 13 12 TENMS 7 6 5 4 TENMS • NOREF Reads as zero. • SKEW Reads as zero • TENMS Read as 0x0002904. The SysTick calibration value is fixed at 0x0002904 (10500), which allows the generation of a time base of 1 ms with SysTick clock at 10.5 MHz (84/8 = 10.5 MHz) 12.21.5 SysTick design hints and tips The SysTick counter runs on the processor clock. If this clock signal is stopped for low power mode, the SysTick counter stops. Ensure software uses aligned word accesses to access the SysTick registers. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 193 12.22 Memory protection unit This section describes the Memory protection unit (MPU). The MPU divides the memory map into a number of regions, and defines the location, size, access permissions, and memory attributes of each region. It supports:  independent attribute settings for each region  overlapping regions  export of memory attributes to the system. The memory attributes affect the behavior of memory accesses to the region. The Cortex-M3 MPU defines:  eight separate memory regions, 0-7  a background region. When memory regions overlap, a memory access is affected by the attributes of the region with the highest number. For example, the attributes for region 7 take precedence over the attributes of any region that overlaps region 7. The background region has the same memory access attributes as the default memory map, but is accessible from privileged software only. The Cortex-M3 MPU memory map is unified. This means instruction accesses and data accesses have same region settings. If a program accesses a memory location that is prohibited by the MPU, the processor generates a memory management fault. This causes a fault exception, and might cause termination of the process in an OS environment. In an OS environment, the kernel can update the MPU region setting dynamically based on the process to be executed. Typically, an embedded OS uses the MPU for memory protection. Configuration of MPU regions is based on memory types, see “Memory regions, types and attributes” on page 58. Table 12-34 shows the possible MPU region attributes. These include Share ability and cache behavior attributes that are not relevant to most microcontroller implementations. See “MPU configuration for a microcontroller” on page 206 for guidelines for programming such an implementation. Table 12-34. Memory attributes summary Memory type Shareability Other attributes Description Strongly- ordered - - All accesses to Strongly-ordered memory occur in program order. All Strongly-ordered regions are assumed to be shared. Device Shared - Memory-mapped peripherals that several processors share. Non-shared - Memory-mapped peripherals that only a single processor uses. Normal Shared Normal memory that is shared between several processors. Non-shared Normal memory that only a single processor uses. Use the MPU registers to define the MPU regions and their attributes. The MPU registers are: 194 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 12-35. MPU registers summary Address Name Type Required privilege Reset value Description 0xE000ED90 TYPE RO Privileged 0x00000800 “MPU Type Register” on page 196 0xE000ED94 CTRL RW Privileged 0x00000000 “MPU Control Register” on page 197 0xE000ED98 RNR RW Privileged 0x00000000 “MPU Region Number Register” on page 199 0xE000ED9C RBAR RW Privileged 0x00000000 “MPU Region Base Address Register” on page 200 0xE000EDA0 RASR RW Privileged 0x00000000 “MPU Region Attribute and Size Register” on page 201 0xE000EDA4 RBAR_A1 RW Privileged 0x00000000 Alias of RBAR, see “MPU Region Base Address Register” on page 200 0xE000EDA8 RASR_A1 RW Privileged 0x00000000 Alias of RASR, see “MPU Region Attribute and Size Register” on page 201 0xE000EDAC RBAR_A2 RW Privileged 0x00000000 Alias of RBAR, see “MPU Region Base Address Register” on page 200 0xE000EDB0 RASR_A2 RW Privileged 0x00000000 Alias of RASR, see “MPU Region Attribute and Size Register” on page 201 0xE000EDB4 RBAR_A3 RW Privileged 0x00000000 Alias of RBAR, see “MPU Region Base Address Register” on page 200 0xE000EDB8 RASR_A3 RW Privileged 0x00000000 Alias of RASR, see “MPU Region Attribute and Size Register” on page 201 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 195 12.22.1 MPU Type Register The TYPE register indicates whether the MPU is present, and if so, how many regions it supports. See the register summary in Table 12-35 on page 195 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 Reserved 23 22 21 20 IREGION 15 14 13 12 DREGION 7 6 5 4 Reserved • IREGION Indicates the number of supported MPU instruction regions. Always contains 0x00. The MPU memory map is unified and is described by the DREGION field. • DREGION Indicates the number of supported MPU data regions: 0x08 = Eight MPU regions. • SEPARATE Indicates support for unified or separate instruction and date memory maps: 0 = unified. 196 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 0 SEPARATE 12.22.2 MPU Control Register The MPU CTRL register:  enables the MPU  enables the default memory map background region  enables use of the MPU when in the hard fault, Non-maskable Interrupt (NMI), and FAULTMASK escalated handlers. See the register summary in Table 12-35 on page 195 for the MPU CTRL attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 2 1 0 PRIVDEFENA HFNMIENA ENABLE Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 4 3 Reserved • PRIVDEFENA Enables privileged software access to the default memory map: 0 = If the MPU is enabled, disables use of the default memory map. Any memory access to a location not covered by any enabled region causes a fault. 1 = If the MPU is enabled, enables use of the default memory map as a background region for privileged software accesses. When enabled, the background region acts as if it is region number -1. Any region that is defined and enabled has priority over this default map. If the MPU is disabled, the processor ignores this bit. • HFNMIENA Enables the operation of MPU during hard fault, NMI, and FAULTMASK handlers. When the MPU is enabled: 0 = MPU is disabled during hard fault, NMI, and FAULTMASK handlers, regardless of the value of the ENABLE bit 1 = the MPU is enabled during hard fault, NMI, and FAULTMASK handlers. When the MPU is disabled, if this bit is set to 1 the behavior is Unpredictable. • ENABLE Enables the MPU: 0 = MPU disabled 1 = MPU enabled. When ENABLE and PRIVDEFENA are both set to 1: For privileged accesses, the default memory map is as described in “Memory model” on page 58. Any access by privileged software that does not address an enabled memory region behaves as defined by the default memory map. Any access by unprivileged software that does not address an enabled memory region causes a memory management fault. XN and Strongly-ordered rules always apply to the System Control Space regardless of the value of the ENABLE bit. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 197 When the ENABLE bit is set to 1, at least one region of the memory map must be enabled for the system to function unless the PRIVDEFENA bit is set to 1. If the PRIVDEFENA bit is set to 1 and no regions are enabled, then only privileged software can operate. When the ENABLE bit is set to 0, the system uses the default memory map. This has the same memory attributes as if the MPU is not implemented, see Table 12-34 on page 194. The default memory map applies to accesses from both privileged and unprivileged software. When the MPU is enabled, accesses to the System Control Space and vector table are always permitted. Other areas are accessible based on regions and whether PRIVDEFENA is set to 1. Unless HFNMIENA is set to 1, the MPU is not enabled when the processor is executing the handler for an exception with priority –1 or –2. These priorities are only possible when handling a hard fault or NMI exception, or when FAULTMASK is enabled. Setting the HFNMIENA bit to 1 enables the MPU when operating with these two priorities. 198 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.22.3 MPU Region Number Register The RNR selects which memory region is referenced by the RBAR and RASR registers. See the register summary in Table 12-35 on page 195 for its attributes. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 Reserved 23 22 21 20 Reserved 15 14 13 12 Reserved 7 6 5 4 REGION • REGION Indicates the MPU region referenced by the RBAR and RASR registers. The MPU supports 8 memory regions, so the permitted values of this field are 0-7. Normally, you write the required region number to this register before accessing the RBAR or RASR. However you can change the region number by writing to the RBAR with the VALID bit set to 1, see “MPU Region Base Address Register” on page 200. This write updates the value of the REGION field. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 199 12.22.4 MPU Region Base Address Register The RBAR defines the base address of the MPU region selected by the RNR, and can update the value of the RNR. See the register summary in Table 12-35 on page 195 for its attributes. Write RBAR with the VALID bit set to 1 to change the current region number and update the RNR. The bit assignments are: 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 N 3 2 1 0 ADDR 23 22 21 20 ADDR 15 14 13 12 ADDR N-1 6 5 Reserved 4 VALID REGION • ADDR Region base address field. The value of N depends on the region size. For more information see “The ADDR field”. • VALID MPU Region Number valid bit: Write: 0 = RNR not changed, and the processor: updates the base address for the region specified in the RNR ignores the value of the REGION field 1 = the processor: updates the value of the RNR to the value of the REGION field updates the base address for the region specified in the REGION field. Always reads as zero. • REGION MPU region field: For the behavior on writes, see the description of the VALID field. On reads, returns the current region number, as specified by the RNR. 12.22.4.1 The ADDR field The ADDR field is bits[31:N] of the RBAR. The region size, as specified by the SIZE field in the RASR, defines the value of N: N = Log2(Region size in bytes), If the region size is configured to 4GB, in the RASR, there is no valid ADDR field. In this case, the region occupies the complete memory map, and the base address is 0x00000000. The base address is aligned to the size of the region. For example, a 64KB region must be aligned on a multiple of 64KB, for example, at 0x00010000 or 0x00020000. 200 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.22.5 MPU Region Attribute and Size Register The RASR defines the region size and memory attributes of the MPU region specified by the RNR, and enables that region and any subregions. See the register summary in Table 12-35 on page 195 for its attributes. RASR is accessible using word or halfword accesses:  the most significant halfword holds the region attributes  the least significant halfword holds the region size and the region and subregion enable bits. The bit assignments are: 31 30 29 Reserved 23 22 27 Reserved 20 19 21 Reserved 15 28 XN 26 13 12 24 18 17 16 S C B 11 10 9 8 3 2 1 TEX 14 25 AP SRD 7 6 5 4 Reserved SIZE 0 ENABLE • XN Instruction access disable bit: 0 = instruction fetches enabled 1 = instruction fetches disabled. • AP Access permission field, see Table 12-39 on page 204. • TEX, C, B Memory access attributes, see Table 12-37 on page 203. • S Shareable bit, see Table 12-36 on page 202. • SRD Subregion disable bits. For each bit in this field: 0 = corresponding sub-region is enabled 1 = corresponding sub-region is disabled See “Subregions” on page 205 for more information. Region sizes of 128 bytes and less do not support subregions. When writing the attributes for such a region, write the SRD field as 0x00. • SIZE Specifies the size of the MPU protection region. The minimum permitted value is 3 (b00010), see See “SIZE field values” on page 202 for more information. • ENABLE Region enable bit. For information about access permission, see “MPU access permission attributes”. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 201 12.22.5.1 SIZE field values The SIZE field defines the size of the MPU memory region specified by the RNR. as follows: (Region size in bytes) = 2(SIZE+1) The smallest permitted region size is 32B, corresponding to a SIZE value of 4. Table 12-36 gives example SIZE values, with the corresponding region size and value of N in the RBAR. Table 12-36. SIZE value Region size Value of N (1) Note b00100 (4) 32B 5 Minimum permitted size b01001 (9) 1KB 10 - b10011 (19) 1MB 20 - b11101 (29) 1GB 30 - b11111 (31) 4GB b01100 Maximum possible size 1. 202 Example SIZE field values In the RBAR, see “MPU Region Base Address Register” on page 200. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.22.6 MPU access permission attributes This section describes the MPU access permission attributes. The access permission bits, TEX, C, B, S, AP, and XN, of the RASR, control access to the corresponding memory region. If an access is made to an area of memory without the required permissions, then the MPU generates a permission fault. Table 12-37 shows the encodings for the TEX, C, B, and S access permission bits. Table 12-37. TEX C 0 TEX, C, B, and S encoding B S (1) 0 x 1 x (1) Memory type Shareability Other attributes Strongly-ordered Shareable - Device Shareable - 0 b000 Not shareable 0 Normal 1 Outer and inner write-through. No write allocate. Shareable 1 0 Not shareable 1 Normal 1 0 0 Not shareable 0 Normal 1 Shareable (1) 1 x 0 x (1) b001 Reserved encoding - Implementation defined attributes. - 0 1 Not shareable 1 Normal 1 x (1) Device 1 x (1) Reserved encoding - (1) Reserved encoding - (1) 1 x A A x 0 b1BB Not shareable Nonshared Device. Not shareable Normal 1 1. Outer and inner write-back. Write and read allocate. Shareable 0 0 b010 Outer and inner write-back. No write allocate. Shareable Shareable The MPU ignores the value of this bit. Table 12-38 shows the cache policy for memory attribute encodings with a TEX value is in the range 4-7. Table 12-38. Cache policy for memory attribute encoding Encoding, AA or BB Corresponding cache policy 00 Non-cacheable 01 Write back, write and read allocate 10 Write through, no write allocate 11 Write back, no write allocate SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 203 Table 12-39 shows the AP encodings that define the access permissions for privileged and unprivileged software. Table 12-39. AP encoding AP[2:0] Privileged permissions Unprivileged permissions Description 000 No access No access All accesses generate a permission fault 001 RW No access Access from privileged software only 010 RW RO Writes by unprivileged software generate a permission fault 011 RW RW Full access 100 Unpredictable Unpredictable Reserved 101 RO No access Reads by privileged software only 110 RO RO Read only, by privileged or unprivileged software 111 RO RO Read only, by privileged or unprivileged software 12.22.7 MPU mismatch When an access violates the MPU permissions, the processor generates a memory management fault, see “Exceptions and interrupts” on page 57. The MMFSR indicates the cause of the fault. See “Memory Management Fault Status Register” on page 180 for more information. 12.22.8 Updating an MPU region To update the attributes for an MPU region, update the RNR, RBAR and RASR registers. You can program each register separately, or use a multiple-word write to program all of these registers. You can use the RBAR and RASR aliases to program up to four regions simultaneously using an STM instruction. 12.22.8.1 Updating an MPU region using separate words Simple code to configure one region: ; R1 = region number ; R2 = size/enable ; R3 = attributes ; R4 = address LDR R0,=MPU_RNR STR R1, [R0, #0x0] STR R4, [R0, #0x4] STRH R2, [R0, #0x8] STRH R3, [R0, #0xA] ; ; ; ; ; 0xE000ED98, MPU region number register Region Number Region Base Address Region Size and Enable Region Attribute Disable a region before writing new region settings to the MPU if you have previously enabled the region being changed. For example: ; R1 = region number ; R2 = size/enable ; R3 = attributes ; R4 = address LDR R0,=MPU_RNR ; 0xE000ED98, MPU region number register STR R1, [R0, #0x0] ; Region Number BIC R2, R2, #1 ; Disable STRH R2, [R0, #0x8] ; Region Size and Enable STR R4, [R0, #0x4] ; Region Base Address STRH R3, [R0, #0xA] ; Region Attribute ORR R2, #1 ; Enable STRH R2, [R0, #0x8] ; Region Size and Enable 204 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Software must use memory barrier instructions:  before MPU setup if there might be outstanding memory transfers, such as buffered writes, that might be affected by the change in MPU settings  after MPU setup if it includes memory transfers that must use the new MPU settings. However, memory barrier instructions are not required if the MPU setup process starts by entering an exception handler, or is followed by an exception return, because the exception entry and exception return mechanism cause memory barrier behavior. Software does not need any memory barrier instructions during MPU setup, because it accesses the MPU through the PPB, which is a Strongly-Ordered memory region. For example, if you want all of the memory access behavior to take effect immediately after the programming sequence, use a DSB instruction and an ISB instruction. A DSB is required after changing MPU settings, such as at the end of context switch. An ISB is required if the code that programs the MPU region or regions is entered using a branch or call. If the programming sequence is entered using a return from exception, or by taking an exception, then you do not require an ISB. 12.22.8.2 Updating an MPU region using multi-word writes You can program directly using multi-word writes, depending on how the information is divided. Consider the following reprogramming: ; R1 = region number ; R2 = address ; R3 = size, attributes in one LDR R0, =MPU_RNR ; 0xE000ED98, MPU region number register STR R1, [R0, #0x0] ; Region Number STR R2, [R0, #0x4] ; Region Base Address STR R3, [R0, #0x8] ; Region Attribute, Size and Enable Use an STM instruction to optimize this: ; R1 = region number ; R2 = address ; R3 = size, attributes in one LDR R0, =MPU_RNR ; 0xE000ED98, MPU region number register STM R0, {R1-R3} ; Region Number, address, attribute, size and enable You can do this in two words for pre-packed information. This means that the RBAR contains the required region number and had the VALID bit set to 1, see “MPU Region Base Address Register” on page 200. Use this when the data is statically packed, for example in a boot loader: ; R1 = address and region number in one ; R2 = size and attributes in one LDR R0, =MPU_RBAR ; 0xE000ED9C, MPU Region Base register STR R1, [R0, #0x0] ; Region base address and ; region number combined with VALID (bit 4) set to 1 STR R2, [R0, #0x4] ; Region Attribute, Size and Enable Use an STM instruction to optimize this: ; R1 = address and region number in one ; R2 = size and attributes in one LDR R0,=MPU_RBAR ; 0xE000ED9C, MPU Region Base register STM R0, {R1-R2} ; Region base address, region number and VALID bit, ; and Region Attribute, Size and Enable 12.22.8.3 Subregions Regions of 256 bytes or more are divided into eight equal-sized subregions. Set the corresponding bit in the SRD field of the RASR to disable a subregion, see “MPU Region Attribute and Size Register” on page 201. The least significant bit of SRD controls the first subregion, and the most significant bit controls the last subregion. Disabling SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 205 a subregion means another region overlapping the disabled range matches instead. If no other enabled region overlaps the disabled subregion the MPU issues a fault. Regions of 32, 64, and 128 bytes do not support subregions, With regions of these sizes, you must set the SRD field to 0x00, otherwise the MPU behavior is Unpredictable. 12.22.8.4 Example of SRD use Two regions with the same base address overlap. Region one is 128KB, and region two is 512KB. To ensure the attributes from region one apply to the first128KB region, set the SRD field for region two to b00000011 to disable the first two subregions, as Figure 12-9 shows Figure 12-9. SRD use 5HJLRQZLWK VXEUHJLRQV 5HJLRQ %DVHDGGUHVVRIERWKUHJLRQV 2IIVHWIURP EDVHDGGUHVV .% .% .% .% .% .% .% 'LVDEOHGVXEUHJLRQ .% 'LVDEOHGVXEUHJLRQ  12.22.9 MPU design hints and tips To avoid unexpected behavior, disable the interrupts before updating the attributes of a region that the interrupt handlers might access. Ensure software uses aligned accesses of the correct size to access MPU registers:  except for the RASR, it must use aligned word accesses  for the RASR it can use byte or aligned halfword or word accesses. The processor does not support unaligned accesses to MPU registers. When setting up the MPU, and if the MPU has previously been programmed, disable unused regions to prevent any previous region settings from affecting the new MPU setup. 12.22.9.1 MPU configuration for a microcontroller Usually, a microcontroller system has only a single processor and no caches. In such a system, program the MPU as follows: Table 12-40. Memory region attributes for a microcontroller Memory region TEX C B S Memory type and attributes Flash memory b000 1 0 0 Normal memory, Non-shareable, write-through Internal SRAM b000 1 0 1 Normal memory, Shareable, write-through External SRAM b000 1 1 1 Normal memory, Shareable, write-back, write-allocate Peripherals b000 0 1 1 Device memory, Shareable In most microcontroller implementations, the share ability and cache policy attributes do not affect the system behavior. However, using these settings for the MPU regions can make the application code more portable. The values given are for typical situations. In special systems, such as multiprocessor designs or designs with a separate DMA engine, the share ability attribute might be important. In these cases refer to the recommendations of the memory device manufacturer. 206 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 12.23 Glossary This glossary describes some of the terms used in technical documents from ARM. Abort A mechanism that indicates to a processor that the value associated with a memory access is invalid. An abort can be caused by the external or internal memory system as a result of attempting to access invalid instruction or data memory. Aligned A data item stored at an address that is divisible by the number of bytes that defines the data size is said to be aligned. Aligned words and halfwords have addresses that are divisible by four and two respectively. The terms word-aligned and halfword-aligned therefore stipulate addresses that are divisible by four and two respectively. Banked register A register that has multiple physical copies, where the state of the processor determines which copy is used. The Stack Pointer, SP (R13) is a banked register. Base register In instruction descriptions, a register specified by a load or store instruction that is used to hold the base value for the instruction’s address calculation. Depending on the instruction and its addressing mode, an offset can be added to or subtracted from the base register value to form the address that is sent to memory. See also “Index register” Breakpoint A breakpoint is a mechanism provided by debuggers to identify an instruction at which program execution is to be halted. Breakpoints are inserted by the programmer to enable inspection of register contents, memory locations, variable values at fixed points in the program execution to test that the program is operating correctly. Breakpoints are removed after the program is successfully tested. Condition field A four-bit field in an instruction that specifies a condition under which the instruction can execute. Conditional execution If the condition code flags indicate that the corresponding condition is true when the instruction starts executing, it executes normally. Otherwise, the instruction does nothing. Context The environment that each process operates in for a multitasking operating system. In ARM processors, this is limited to mean the physical address range that it can access in memory and the associated memory access permissions. Coprocessor A processor that supplements the main processor. Cortex-M3 does not support any coprocessors. Debugger A debugging system that includes a program, used to detect, locate, and correct software faults, together with custom hardware that supports software debugging. Direct Memory Access (DMA) An operation that accesses main memory directly, without the processor performing any accesses to the data concerned. Doubleword A 64-bit data item. The contents are taken as being an unsigned integer unless otherwise stated. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 207 Doubleword-aligned A data item having a memory address that is divisible by eight. Endianness Byte ordering. The scheme that determines the order that successive bytes of a data word are stored in memory. An aspect of the system’s memory mapping. See also “Little-endian (LE)” Exception An event that interrupts program execution. When an exception occurs, the processor suspends the normal program flow and starts execution at the address indicated by the corresponding exception vector. The indicated address contains the first instruction of the handler for the exception. An exception can be an interrupt request, a fault, or a software-generated system exception. Faults include attempting an invalid memory access, attempting to execute an instruction in an invalid processor state, and attempting to execute an undefined instruction. Exception service routine See “Interrupt handler”. Exception vector See “Interrupt vector”. Flat address mapping A system of organizing memory in which each physical address in the memory space is the same as the corresponding virtual address. Halfword A 16-bit data item. Illegal instruction An instruction that is architecturally Undefined. Implementation-defined The behavior is not architecturally defined, but is defined and documented by individual implementations. Implementation-specific The behavior is not architecturally defined, and does not have to be documented by individual implementations. Used when there are a number of implementation options available and the option chosen does not affect software compatibility. Index register In some load and store instruction descriptions, the value of this register is used as an offset to be added to or subtracted from the base register value to form the address that is sent to memory. Some addressing modes optionally enable the index register value to be shifted prior to the addition or subtraction. See also “Base register” Instruction cycle count The number of cycles that an instruction occupies the Execute stage of the pipeline. Interrupt handler A program that control of the processor is passed to when an interrupt occurs. Interrupt vector One of a number of fixed addresses in low memory, or in high memory if high vectors are configured, that contains the first instruction of the corresponding interrupt handler. 208 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Little-endian (LE) Byte ordering scheme in which bytes of increasing significance in a data word are stored at increasing addresses in memory. See also “Condition field”, “Endianness”. Little-endian memory Memory in which: a byte or halfword at a word-aligned address is the least significant byte or halfword within the word at that address a byte at a halfword-aligned address is the least significant byte within the halfword at that address. Load/store architecture A processor architecture where data-processing operations only operate on register contents, not directly on memory contents. Memory Protection Unit (MPU) Hardware that controls access permissions to blocks of memory. An MPU does not perform any address translation. Prefetching In pipelined processors, the process of fetching instructions from memory to fill up the pipeline before the preceding instructions have finished executing. Prefetching an instruction does not mean that the instruction has to be executed. Read Reads are defined as memory operations that have the semantics of a load. Reads include the Thumb instructions LDM, LDR, LDRSH, LDRH, LDRSB, LDRB, and POP. Region A partition of memory space. Reserved A field in a control register or instruction format is reserved if the field is to be defined by the implementation, or produces Unpredictable results if the contents of the field are not zero. These fields are reserved for use in future extensions of the architecture or are implementation-specific. All reserved bits not used by the implementation must be written as 0 and read as 0. Should Be One (SBO) Write as 1, or all 1s for bit fields, by software. Writing as 0 produces Unpredictable results. Should Be Zero (SBZ) Write as 0, or all 0s for bit fields, by software. Writing as 1 produces Unpredictable results. Should Be Zero or Preserved (SBZP) Write as 0, or all 0s for bit fields, by software, or preserved by writing the same value back that has been previously read from the same field on the same processor. Thread-safe In a multi-tasking environment, thread-safe functions use safeguard mechanisms when accessing shared resources, to ensure correct operation without the risk of shared access conflicts. Thumb instruction One or two halfwords that specify an operation for a processor to perform. Thumb instructions must be halfwordaligned. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 209 Unaligned A data item stored at an address that is not divisible by the number of bytes that defines the data size is said to be unaligned. For example, a word stored at an address that is not divisible by four. Undefined Indicates an instruction that generates an Undefined instruction exception. Unpredictable (UNP) You cannot rely on the behavior. Unpredictable behavior must not represent security holes. Unpredictable behavior must not halt or hang the processor, or any parts of the system. Warm reset Also known as a core reset. Initializes the majority of the processor excluding the debug controller and debug logic. This type of reset is useful if you are using the debugging features of a processor. Word A 32-bit data item. Write Writes are defined as operations that have the semantics of a store. Writes include the Thumb instructions STM, STR, STRH, STRB, and PUSH. 210 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 13. Debug and Test Features 13.1 Overview The SAM3U Series microcontrollers feature a number of complementary debug and test capabilities. The Serial Wire/JTAG Debug Port (SWJ-DP) combining a Serial Wire Debug Port (SW-DP) and JTAG Debug (JTAG-DP) port is used for standard debugging functions, such as downloading code and single-stepping through programs. It also embeds a serial wire trace. Figure 13-1. Debug and Test Block Diagram TMS TCK/SWCLK TDI Boundary TAP JTAGSEL SWJ-DP TDO/TRACESWO Reset and Test 13.2 POR TST Embedded Characteristics  Debug access to all memory and registers in the system, including Cortex-M3 register bank when the core is running, halted, or held in reset  Serial Wire Debug Port (SW-DP) and Serial Wire JTAG Debug Port (SWJ-DP) debug access  Flash Patch and Breakpoint (FPB) unit for implementing break points and code patches  Data Watchpoint and Trace (DWT) unit for implementing watch points, data tracing, and system profiling  Instrumentation Trace Macrocell (ITM) for support of printf style debugging  IEEE® 1149.1 JTAG Boundary-scan on all digital pins SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 211 13.3 Application Examples 13.3.1 Debug Environment Figure 13-2 shows a complete debug environment example. The SWJ-DP interface is used for standard debugging functions, such as downloading code and single-stepping through the program and viewing core and peripheral registers. Figure 13-2. Application Debug Environment Example Host Debugger PC SWJ-DP Emulator/Probe SWJ-DP Connector SAM3 SAM3-based Application Board 13.3.2 Test Environment Figure 13-3 shows a test environment example (JTAG Boundary scan). Test vectors are sent and interpreted by the tester. In this example, the “board in test” is designed using a number of JTAG-compliant devices. These devices can be connected to form a single scan chain. 212 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 13-3. Application Test Environment Example Test Adaptor Tester JTAG Probe JTAG Connector Chip n SAM3 Chip 2 Chip 1 SAM3-based Application Board In Test 13.4 Debug and Test Pin Description Table 13-1. Debug and Test Signal List Signal Name Function Type Active Level Input/Output Low Reset/Test NRST Microcontroller Reset TST Test Select Input SWD/JTAG TCK/SWCLK Test Clock/Serial Wire Clock Input TDI Test Data In Input TDO/TRACESWO Test Data Out/Trace Asynchronous Data Out TMS/SWDIO Test Mode Select/Serial Wire Input/Output Input JTAGSEL JTAG Selection Input Note: 1. Output(1) High TDO pin is set in input mode when the Cortex-M3 Core is not in debug mode. Thus an external pull-up (100 kΩ) must be added to avoid current consumption due to floating input. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 213 13.5 Functional Description 13.5.1 Test Pin One dedicated pin, TST, is used to define the device operating mode. When this pin is at low level during powerup, the device is in normal operating mode. When at high level, the device is in test mode or FFPI mode. The TST pin integrates a permanent pull-down resistor of about 15 kΩ,so that it can be left unconnected for normal operation. Note that when setting the TST pin to low or high level at power up, it must remain in the same state during the duration of the whole operation. 13.5.2 Debug Architecture Figure 13-4 shows the Debug Architecture used in the SAM3. The Cortex-M3 embeds five functional units for debug:  SWJ-DP (Serial Wire/JTAG Debug Port)  FPB (Flash Patch Breakpoint)  DWT (Data Watchpoint and Trace)  ITM (Instrumentation Trace Macrocell)  TPIU (Trace Port Interface Unit) The debug architecture information that follows is mainly dedicated to developers of SWJ-DP Emulators/Probes and debugging tool vendors for Cortex M3-based microcontrollers. For further details on SWJ-DP see the Cortex M3 technical reference manual. Figure 13-4. Debug Architecture DWT 4 watchpoints FPB SWJ-DP PC sampler 6 breakpoints data address sampler SWD/JTAG data sampler ITM software trace 32 channels interrupt trace time stamping CPU statistics 214 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 SWO trace TPIU 13.5.3 Serial Wire/JTAG Debug Port (SWJ-DP) The Cortex-M3 embeds a SWJ-DP Debug port which is the standard CoreSight™ debug port. It combines Serial Wire Debug Port (SW-DP), from 2 to 3 pins and JTAG debug Port (JTAG-DP), 5 pins. By default, the JTAG Debug Port is active. If the host debugger wants to switch to the Serial Wire Debug Port, it must provide a dedicated JTAG sequence on TMS/SWDIO and TCK/SWCLK which disables JTAG-DP and enables SW-DP. When the Serial Wire Debug Port is active, TDO/TRACESWO can be used for trace. The asynchronous TRACE output (TRACESWO) is multiplexed with TDO. The asynchronous trace can only be used with SW-DP, not JTAGDP. Table 13-2. SWJ-DP Pin List Pin Name JTAG Port Serial Wire Debug Port TMS/SWDIO TMS SWDIO TCK/SWCLK TCK SWCLK TDI TDI – TDO/TRACESWO TDO TRACESWO (optional: trace) SW-DP or JTAG-DP mode is selected when JTAGSEL is low. It is not possible to switch directly between SWJ-DP and JTAG boundary scan operations. A chip reset must be performed after JTAGSEL is changed. 13.5.3.1 SW-DP and JTAG-DP Selection Mechanism Debug port selection mechanism is done by sending specific SWDIOTMS sequence. The JTAG-DP is selected by default after reset.  Switch from JTAG-DP to SW-DP. The sequence is: ̶ Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1 ̶ Send the 16-bit sequence on SWDIOTMS = 0111100111100111 (0x79E7 MSB first) ̶  Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1 Switch from SWD to JTAG. The sequence is: ̶ ̶ ̶ Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1 Send the 16-bit sequence on SWDIOTMS = 0011110011100111 (0x3CE7 MSB first) Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1 13.5.4 FPB (Flash Patch Breakpoint) The FPB:  Implements hardware breakpoints  Patches code and data from code space to system space. The FPB unit contains:  Two literal comparators for matching against literal loads from Code space, and remapping to a corresponding area in System space.  Six instruction comparators for matching against instruction fetches from Code space and remapping to a corresponding area in System space.  Alternatively, comparators can also be configured to generate a Breakpoint instruction to the processor core on a match. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 215 13.5.5 DWT (Data Watchpoint and Trace) The DWT contains four comparators which can be configured to generate the following:  PC sampling packets at set intervals  PC or Data watchpoint packets  Watchpoint event to halt core The DWT contains counters for the items that follow:  Clock cycle (CYCCNT)  Folded instructions  Load Store Unit (LSU) operations  Sleep Cycles  CPI (all instruction cycles except for the first cycle)  Interrupt overhead 13.5.6 ITM (Instrumentation Trace Macrocell) The ITM is an application driven trace source that supports printf style debugging to trace Operating System (OS) and application events, and emits diagnostic system information. The ITM emits trace information as packets which can be generated by three different sources with several priority levels:  Software trace: Software can write directly to ITM stimulus registers. This can be done thanks to the “printf” function. For more information, refer to Section 13.5.6.1 “How to Configure the ITM”.  Hardware trace: The ITM emits packets generated by the DWT.  Time stamping: Timestamps are emitted relative to packets. The ITM contains a 21-bit counter to generate the timestamp. 13.5.6.1 How to Configure the ITM The following example describes how to output trace data in asynchronous trace mode.  Configure the TPIU for asynchronous trace mode (refer to Section 13.5.6.3 “5.4.3. How to Configure the TPIU”)  Enable the write accesses into the ITM registers by writing “0xC5ACCE55” into the Lock Access Register (Address: 0xE0000FB0)  Write 0x00010015 into the Trace Control Register:  ̶ Enable ITM ̶ Enable Synchronization packets ̶ Enable SWO behavior ̶ Fix the ATB ID to 1 Write 0x1 into the Trace Enable Register: ̶  Enable the Stimulus port 0 Write 0x1 into the Trace Privilege Register: ̶  Stimulus port 0 only accessed in privileged mode (Clearing a bit in this register will result in the corresponding stimulus port being accessible in user mode.) Write into the Stimulus port 0 register: TPIU (Trace Port Interface Unit) The TPIU acts as a bridge between the on-chip trace data and the Instruction Trace Macrocell (ITM). The TPIU formats and transmits trace data off-chip at frequencies asynchronous to the core. 216 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 13.5.6.2 Asynchronous Mode The TPIU is configured in asynchronous mode, trace data are output using the single TRACESWO pin. The TRACESWO signal is multiplexed with the TDO signal of the JTAG Debug Port. As a consequence, asynchronous trace mode is only available when the Serial Wire Debug mode is selected since TDO signal is used in JTAG debug mode. Two encoding formats are available for the single pin output:  Manchester encoded stream. This is the reset value.  NRZ_based UART byte structure 13.5.6.3 5.4.3. How to Configure the TPIU This example only concerns the asynchronous trace mode.  Set the TRCENA bit to 1 into the Debug Exception and Monitor Register (0xE000EDFC) to enable the use of trace and debug blocks.  Write 0x2 into the Selected Pin Protocol Register ̶ Select the Serial Wire Output – NRZ  Write 0x100 into the Formatter and Flush Control Register  Set the suitable clock prescaler value into the Async Clock Prescaler Register to scale the baud rate of the asynchronous output (this can be done automatically by the debugging tool). 13.5.7 IEEE 1149.1 JTAG Boundary Scan IEEE 1149.1 JTAG Boundary Scan allows pin-level access independent of the device packaging technology. IEEE 1149.1 JTAG Boundary Scan is enabled when FWUP, NRST, NRSTB and JTAGSEL are high while TST is tied low during power-up and must be kept in this state during the whole boundary scan operation. The SAMPLE, EXTEST and BYPASS functions are implemented. In SWD/JTAG debug mode, the ARM processor responds with a non-JTAG chip ID that identifies the processor. This is not IEEE 1149.1 JTAG-compliant. It is not possible to switch directly between JTAG Boundary Scan and SWJ Debug Port operations. A chip reset must be performed after JTAGSEL is changed. A Boundary-scan Descriptor Language (BSDL) file to set up the test is provided on www.atmel.com. 13.5.7.1 JTAG Boundary-scan Register The Boundary-scan Register (BSR) contains a number of bits which correspond to active pins and associated control signals. Each SAM3 input/output pin corresponds to a 3-bit register in the BSR. The OUTPUT bit contains data that can be forced on the pad. The INPUT bit facilitates the observability of data applied to the pad. The CONTROL bit selects the direction of the pad. For more information, please refer to BDSL files available for the SAM3U Series. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 217 13.5.8 ID Code Register Access: Read-only 31 30 29 28 27 VERSION 23 22 26 25 24 PART NUMBER 21 20 19 18 17 16 10 9 8 PART NUMBER 15 14 13 12 11 PART NUMBER 7 6 MANUFACTURER IDENTITY 5 4 3 2 1 MANUFACTURER IDENTITY • VERSION[31:28]: Product Version Number Set to 0x0. • PART NUMBER[27:12]: Product Part Number Chip Name Chip ID SAM3U 0x5B2A • MANUFACTURER IDENTITY[11:1] Set to 0x01F. • Bit[0] Required by IEEE Std. 1149.1 Set to 0x1. Chip Name SAM3U 218 JTAG ID Code 05B2_A03F SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 0 1 14. Watchdog Timer (WDT) 14.1 Description The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in a deadlock. It features a 12-bit down counter that allows a watchdog period of up to 16 seconds (slow clock at 32.768 kHz). It can generate a general reset or a processor reset only. In addition, it can be stopped while the processor is in debug mode or idle mode. 14.2 Block Diagram Figure 14-1. Watchdog Timer Block Diagram write WDT_MR WDT_MR WDV WDT_CR WDRSTT reload 1 0 12-bit Down Counter WDT_MR WDD reload Current Value 1/128 SLCK = EXTERNAL RESET LENGTH 15.3.4.4 Software Reset The Reset Controller offers several commands used to assert the different reset signals. These commands are performed by writing the Control Register (RSTC_CR) with the following bits at 1: 230  PROCRST: Writing PROCRST at 1 resets the processor and the watchdog timer.  PERRST: Writing PERRST at 1 resets all the embedded peripherals, including the memory system, and, in particular, the Remap Command. The Peripheral Reset is generally used for debug purposes.  EXTRST: Writing EXTRST at 1 asserts low the NRST pin during a time defined by the field ERSTL in the Mode Register (RSTC_MR). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 The software reset is entered if at least one of these bits is set by the software. All these commands can be performed independently or simultaneously. The software reset lasts 3 Slow Clock cycles. The internal reset signals are asserted as soon as the register write is performed. This is detected on the Master Clock (MCK). They are released when the software reset is left, i.e., synchronously to SLCK. If EXTRST is set, the nrst_out signal is asserted depending on the programming of the field ERSTL. However, the resulting falling edge on NRST does not lead to a User Reset. If and only if the PROCRST bit is set, the Reset Controller reports the software status in the field RSTTYP of the Status Register (RSTC_SR). Other Software Resets are not reported in RSTTYP. As soon as a software operation is detected, the bit SRCMP (Software Reset Command in Progress) is set in the Status Register (RSTC_SR). It is cleared as soon as the software reset is left. No other software reset can be performed while the SRCMP bit is set, and writing any value in RSTC_CR has no effect. Figure 15-5. Software Reset SLCK MCK Any Freq. Write RSTC_CR Resynch. Processor Startup 1 cycle = 2 cycles proc_nreset if PROCRST=1 RSTTYP Any XXX 0x3 = Software Reset periph_nreset if PERRST=1 NRST (nrst_out) if EXTRST=1 EXTERNAL RESET LENGTH 8 cycles (ERSTL=2) SRCMP in RSTC_SR 15.3.4.5 Watchdog Reset The Watchdog Reset is entered when a watchdog fault occurs. This state lasts 3 Slow Clock cycles. When in Watchdog Reset, assertion of the reset signals depends on the WDRPROC bit in WDT_MR:  If WDRPROC is 0, the Processor Reset and the Peripheral Reset are asserted. The NRST line is also asserted, depending on the programming of the field ERSTL. However, the resulting low level on NRST does not result in a User Reset state.  If WDRPROC = 1, only the processor reset is asserted. The Watchdog Timer is reset by the proc_nreset signal. As the watchdog fault always causes a processor reset if WDRSTEN is set, the Watchdog Timer is always reset after a Watchdog Reset, and the Watchdog is enabled by default and with a period set to a maximum. When the WDRSTEN in WDT_MR bit is reset, the watchdog fault has no impact on the reset controller. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 231 Figure 15-6. Watchdog Reset SLCK MCK Any Freq. wd_fault Processor Startup = 2 cycles proc_nreset RSTTYP Any 0x2 = Watchdog Reset XXX periph_nreset Only if WDRPROC = 0 NRST (nrst_out) EXTERNAL RESET LENGTH 8 cycles (ERSTL=2) 15.3.5 Reset State Priorities The Reset State Manager manages the following priorities between the different reset sources, given in descending order:  General Reset  Backup Reset  Watchdog Reset  Software Reset  User Reset Particular cases are listed below:  When in User Reset: ̶ A watchdog event is impossible because the Watchdog Timer is being reset by the proc_nreset signal. ̶   232 A software reset is impossible, since the processor reset is being activated. When in Software Reset: ̶ A watchdog event has priority over the current state. ̶ The NRST has no effect. When in Watchdog Reset: ̶ The processor reset is active and so a Software Reset cannot be programmed. ̶ A User Reset cannot be entered. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 15.3.6 Reset Controller Status Register The Reset Controller status register (RSTC_SR) provides several status fields:  RSTTYP field: This field gives the type of the last reset, as explained in previous sections.  SRCMP bit: This field indicates that a Software Reset Command is in progress and that no further software reset should be performed until the end of the current one. This bit is automatically cleared at the end of the current software reset.  NRSTL bit: The NRSTL bit of the Status Register gives the level of the NRST pin sampled on each MCK rising edge.  URSTS bit: A high-to-low transition of the NRST pin sets the URSTS bit of the RSTC_SR register. This transition is also detected on the Master Clock (MCK) rising edge (see Figure 15-7). If the User Reset is disabled (URSTEN = 0) and if the interruption is enabled by the URSTIEN bit in the RSTC_MR register, the URSTS bit triggers an interrupt. Reading the RSTC_SR status register resets the URSTS bit and clears the interrupt. Figure 15-7. Reset Controller Status and Interrupt MCK read RSTC_SR Peripheral Access 2 cycle resynchronization 2 cycle resynchronization NRST NRSTL URSTS rstc_irq if (URSTEN = 0) and (URSTIEN = 1) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 233 15.4 Reset Controller (RSTC) User Interface Table 15-1. Register Mapping Offset Register Name 0x00 Control Register 0x04 0x08 234 Access Reset RSTC_CR Write-only - Status Register RSTC_SR Read-only 0x0000_0000 Mode Register RSTC_MR Read-write 0x0000_0000 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 15.4.1 Reset Controller Control Register Name: RSTC_CR Address: 0x400E1200 Access Type: Write-only 31 30 29 28 27 26 25 24 KEY 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 8 – 7 – 6 – 5 – 4 – 3 EXTRST 2 PERRST 1 – 0 PROCRST • PROCRST: Processor Reset 0 = No effect. 1 = If KEY is correct, resets the processor. • PERRST: Peripheral Reset 0 = No effect. 1 = If KEY is correct, resets the peripherals. • EXTRST: External Reset 0 = No effect. 1 = If KEY is correct, asserts the NRST pin. • KEY: Password Should be written at value 0xA5. Writing any other value in this field aborts the write operation. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 235 15.4.2 Reset Controller Status Register Name: RSTC_SR Address: 0x400E1204 Access Type: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 SRCMP 16 NRSTL 15 – 14 – 13 – 12 – 11 – 10 9 RSTTYP 8 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 URSTS • URSTS: User Reset Status 0 = No high-to-low edge on NRST happened since the last read of RSTC_SR. 1 = At least one high-to-low transition of NRST has been detected since the last read of RSTC_SR. • RSTTYP: Reset Type Reports the cause of the last processor reset. Reading this RSTC_SR does not reset this field. RSTTYP Reset Type Comments 0 0 0 General Reset First power-up Reset 0 0 1 Backup Reset Return from Backup mode 0 1 0 Watchdog Reset Watchdog fault occurred 0 1 1 Software Reset Processor reset required by the software 1 0 0 User Reset NRST pin detected low • NRSTL: NRST Pin Level Registers the NRST Pin Level at Master Clock (MCK). • SRCMP: Software Reset Command in Progress 0 = No software command is being performed by the reset controller. The reset controller is ready for a software command. 1 = A software reset command is being performed by the reset controller. The reset controller is busy. 236 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 15.4.3 Reset Controller Mode Register Name: RSTC_MR Address: 0x400E1208 Access Type: Read-write 31 30 29 28 27 26 25 24 17 – 16 – 9 8 1 – 0 URSTEN KEY 23 – 22 – 21 – 20 – 19 – 18 – 15 – 14 – 13 – 12 – 11 10 7 – 6 – 5 4 URSTIEN 3 – ERSTL 2 – • URSTEN: User Reset Enable 0 = The detection of a low level on the pin NRST does not generate a User Reset. 1 = The detection of a low level on the pin NRST triggers a User Reset. • URSTIEN: User Reset Interrupt Enable 0 = USRTS bit in RSTC_SR at 1 has no effect on rstc_irq. 1 = USRTS bit in RSTC_SR at 1 asserts rstc_irq if URSTEN = 0. • ERSTL: External Reset Length This field defines the external reset length. The external reset is asserted during a time of 2(ERSTL+1) Slow Clock cycles. This allows assertion duration to be programmed between 60 µs and 2 seconds. • KEY: Password Should be written at value 0xA5. Writing any other value in this field aborts the write operation. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 237 16. Real-time Timer (RTT) 16.1 Description The Real-time Timer is built around a 32-bit counter used to count roll-over events of the programmable 16-bit prescaler which enables counting elapsed seconds from a 32 kHz slow clock source. It generates a periodic interrupt and/or triggers an alarm on a programmed value. 16.2 16.3 Embedded Characteristics  32-bit Free-running Counter on prescaled slow clock  16-bit Configurable Prescaler  Interrupt on Alarm Block Diagram Figure 16-1. Real-time Timer RTT_MR RTTRST RTT_MR RTPRES RTT_MR SLCK RTTINCIEN reload 16-bit Divider set 0 RTT_MR RTTRST RTT_SR 1 RTTINC reset 0 rtt_int 32-bit Counter read RTT_SR RTT_MR ALMIEN RTT_VR reset CRTV RTT_SR ALMS set = RTT_AR 238 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 ALMV rtt_alarm 16.4 Functional Description The Real-time Timer can be used to count elapsed seconds. It is built around a 32-bit counter fed by Slow Clock divided by a programmable 16-bit value. The value can be programmed in the field RTPRES of the Real-time Mode Register (RTT_MR). Programming RTPRES at 0x00008000 corresponds to feeding the real-time counter with a 1 Hz signal (if the Slow Clock is 32.768 kHz). The 32-bit counter can count up to 232 seconds, corresponding to more than 136 years, then roll over to 0. The Real-time Timer can also be used as a free-running timer with a lower time-base. The best accuracy is achieved by writing RTPRES to 3. Programming RTPRES to 1 or 2 is possible, but may result in losing status events because the status register is cleared two Slow Clock cycles after read. Thus if the RTT is configured to trigger an interrupt, the interrupt occurs during 2 Slow Clock cycles after reading RTT_SR. To prevent several executions of the interrupt handler, the interrupt must be disabled in the interrupt handler and re-enabled when the status register is clear. The Real-time Timer value (CRTV) can be read at any time in the register RTT_VR (Real-time Value Register). As this value can be updated asynchronously from the Master Clock, it is advisable to read this register twice at the same value to improve accuracy of the returned value. The current value of the counter is compared with the value written in the alarm register RTT_AR (Real-time Alarm Register). If the counter value matches the alarm, the bit ALMS in RTT_SR is set. The alarm register is set to its maximum value, corresponding to 0xFFFF_FFFF, after a reset. The bit RTTINC in RTT_SR is set each time the Real-time Timer counter is incremented. This bit can be used to start a periodic interrupt, the period being one second when the RTPRES is programmed with 0x8000 and Slow Clock equal to 32.768 Hz. Reading the RTT_SR status register resets the RTTINC and ALMS fields. Writing the bit RTTRST in RTT_MR immediately reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter. Note: Because of the asynchronism between the Slow Clock (SCLK) and the System Clock (MCK): 1) The restart of the counter and the reset of the RTT_VR current value register is effective only 2 slow clock cycles after the write of the RTTRST bit in the RTT_MR register. 2) The status register flags reset is taken into account only 2 slow clock cycles after the read of the RTT_SR (Status Register). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 239 Figure 16-2. RTT Counting APB cycle APB cycle SCLK RTPRES - 1 Prescaler 0 RTT 0 ... ALMV-1 ALMV ALMV+1 RTTINC (RTT_SR) ALMS (RTT_SR) APB Interface read RTT_SR 240 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 ALMV+2 ALMV+3 16.5 Real-time Timer (RTT) User Interface Table 16-1. Register Mapping Offset Register Name Access Reset 0x00 Mode Register RTT_MR Read-write 0x0000_8000 0x04 Alarm Register RTT_AR Read-write 0xFFFF_FFFF 0x08 Value Register RTT_VR Read-only 0x0000_0000 0x0C Status Register RTT_SR Read-only 0x0000_0000 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 241 16.5.1 Real-time Timer Mode Register Name: RTT_MR Address: 0x400E1230 Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 RTTRST 17 RTTINCIEN 16 ALMIEN 15 14 13 12 11 10 9 8 3 2 1 0 RTPRES 7 6 5 4 RTPRES • RTPRES: Real-time Timer Prescaler Value Defines the number of SLCK periods required to increment the Real-time timer. RTPRES is defined as follows: RTPRES = 0: The prescaler period is equal to 216 * SCLK period. RTPRES ≠ 0: The prescaler period is equal to RTPRES * SCLK period. • ALMIEN: Alarm Interrupt Enable 0 = The bit ALMS in RTT_SR has no effect on interrupt. 1 = The bit ALMS in RTT_SR asserts interrupt. • RTTINCIEN: Real-time Timer Increment Interrupt Enable 0 = The bit RTTINC in RTT_SR has no effect on interrupt. 1 = The bit RTTINC in RTT_SR asserts interrupt. • RTTRST: Real-time Timer Restart 0 = No effect. 1 = Reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter. 242 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 16.5.2 Real-time Timer Alarm Register Name: RTT_AR Address: 0x400E1234 Access: Read-write 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 ALMV 23 22 21 20 ALMV 15 14 13 12 ALMV 7 6 5 4 ALMV • ALMV: Alarm Value Defines the alarm value (ALMV+1) compared with the Real-time Timer. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 243 16.5.3 Real-time Timer Value Register Name: RTT_VR Address: 0x400E1238 Access: Read-only 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 CRTV 23 22 21 20 CRTV 15 14 13 12 CRTV 7 6 5 4 CRTV • CRTV: Current Real-time Value Returns the current value of the Real-time Timer. 244 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 16.5.4 Real-time Timer Status Register Name: RTT_SR Address: 0x400E123C Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 – 1 RTTINC 0 ALMS • ALMS: Real-time Alarm Status 0 = The Real-time Alarm has not occurred since the last read of RTT_SR. 1 = The Real-time Alarm occurred since the last read of RTT_SR. • RTTINC: Real-time Timer Increment 0 = The Real-time Timer has not been incremented since the last read of the RTT_SR. 1 = The Real-time Timer has been incremented since the last read of the RTT_SR. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 245 17. Real Time Clock (RTC) 17.1 Description The Real-time Clock (RTC) peripheral is designed for very low power consumption. It combines a complete time-of-day clock with alarm and a two-hundred-year Gregorian calendar, complemented by a programmable periodic interrupt. The alarm and calendar registers are accessed by a 32-bit data bus. The time and calendar values are coded in binary-coded decimal (BCD) format. The time format can be 24-hour mode or 12-hour mode with an AM/PM indicator. Updating time and calendar fields and configuring the alarm fields are performed by a parallel capture on the 32-bit data bus. An entry control is performed to avoid loading registers with incompatible BCD format data or with an incompatible date according to the current month/year/century. 17.2 Block Diagram Figure 17-1. 17.3 RTC Block Diagram Slow Clock: SLCK 32768 Divider Bus Interface Bus Interface Time Date Entry Control Interrupt Control RTC Interrupt Product Dependencies 17.3.1 Power Management The Real-time Clock is continuously clocked at 32768 Hz. The Power Management Controller has no effect on RTC behavior. 17.3.2 Interrupt RTC interrupt line is connected on one of the internal sources of the interrupt controller. RTC interrupt requires the interrupt controller to be programmed first. 246 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17.4 Functional Description The RTC provides a full binary-coded decimal (BCD) clock that includes century (19/20), year (with leap years), month, date, day, hours, minutes and seconds. The valid year range is 1900 to 2099 in Gregorian mode, a two-hundred-year calendar. The RTC can operate in 24-hour mode or in 12-hour mode with an AM/PM indicator. Corrections for leap years are included (all years divisible by 4 being leap years). This is correct up to the year 2099. 17.4.1 Reference Clock The reference clock is Slow Clock (SLCK). It can be driven internally or by an external 32.768 kHz crystal. During low power modes of the processor, the oscillator runs and power consumption is critical. The crystal selection has to take into account the current consumption for power saving and the frequency drift due to temperature effect on the circuit for time accuracy. 17.4.2 Timing The RTC is updated in real time at one-second intervals in normal mode for the counters of seconds, at oneminute intervals for the counter of minutes and so on. Due to the asynchronous operation of the RTC with respect to the rest of the chip, to be certain that the value read in the RTC registers (century, year, month, date, day, hours, minutes, seconds) are valid and stable, it is necessary to read these registers twice. If the data is the same both times, then it is valid. Therefore, a minimum of two and a maximum of three accesses are required. 17.4.3 Alarm The RTC has five programmable fields: month, date, hours, minutes and seconds. Each of these fields can be enabled or disabled to match the alarm condition:  If all the fields are enabled, an alarm flag is generated (the corresponding flag is asserted and an interrupt generated if enabled) at a given month, date, hour/minute/second.  If only the “seconds” field is enabled, then an alarm is generated every minute. Depending on the combination of fields enabled, a large number of possibilities are available to the user ranging from minutes to 365/366 days. 17.4.4 Error Checking Verification on user interface data is performed when accessing the century, year, month, date, day, hours, minutes, seconds and alarms. A check is performed on illegal BCD entries such as illegal date of the month with regard to the year and century configured. If one of the time fields is not correct, the data is not loaded into the register/counter and a flag is set in the validity register. The user can not reset this flag. It is reset as soon as an acceptable value is programmed. This avoids any further side effects in the hardware. The same procedure is done for the alarm. The following checks are performed: 1. Century (check if it is in range 19 - 20) 2. Year (BCD entry check) 3. Date (check range 01 - 31) 4. Month (check if it is in BCD range 01 - 12, check validity regarding “date”) 5. Day (check range 1 - 7) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 247 6. Hour (BCD checks: in 24-hour mode, check range 00 - 23 and check that AM/PM flag is not set if RTC is set in 24-hour mode; in 12-hour mode check range 01 - 12) 7. Minute (check BCD and range 00 - 59) 8. Second (check BCD and range 00 - 59) Note: If the 12-hour mode is selected by means of the RTC_MODE register, a 12-hour value can be programmed and the returned value on RTC_TIME will be the corresponding 24-hour value. The entry control checks the value of the AM/PM indicator (bit 22 of RTC_TIME register) to determine the range to be checked. 17.4.5 Updating Time/Calendar To update any of the time/calendar fields, the user must first stop the RTC by setting the corresponding field in the Control Register. Bit UPDTIM must be set to update time fields (hour, minute, second) and bit UPDCAL must be set to update calendar fields (century, year, month, date, day). Then the user must poll or wait for the interrupt (if enabled) of bit ACKUPD in the Status Register. Once the bit reads 1, it is mandatory to clear this flag by writing the corresponding bit in RTC_SCCR. The user can now write to the appropriate Time and Calendar register. Once the update is finished, the user must reset (0) UPDTIM and/or UPDCAL in the Control When entering programming mode of the calendar fields, the time fields remain enabled. When entering the programming mode of the time fields, both time and calendar fields are stopped. This is due to the location of the calendar logic circuity (downstream for low-power considerations). It is highly recommended to prepare all the fields to be updated before entering programming mode. In successive update operations, the user must wait at least one second after resetting the UPDTIM/UPDCAL bit in the RTC_CR (Control Register) before setting these bits again. This is done by waiting for the SEC flag in the Status Register before setting UPDTIM/UPDCAL bit. After resetting UPDTIM/UPDCAL, the SEC flag must also be cleared. 248 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 17-2. Update Sequence Begin Prepare TIme or Calendar Fields Set UPDTIM and/or UPDCAL bit(s) in RTC_CR Read RTC_SR Polling or IRQ (if enabled) ACKUPD =1? No Yes Clear ACKUPD bit in RTC_SCCR Update Time and/or Calendar values in RTC_TIMR/RTC_CALR Clear UPDTIM and/or UPDCAL bit in RTC_CR End SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 249 17.5 Real Time Clock (RTC) User Interface Table 17-1. Offset Register Mapping Register Name Access Reset 0x00 Control Register RTC_CR Read-write 0x0 0x04 Mode Register RTC_MR Read-write 0x0 0x08 Time Register RTC_TIMR Read-write 0x0 0x0C Calendar Register RTC_CALR Read-write 0x01210720 0x10 Time Alarm Register RTC_TIMALR Read-write 0x0 0x14 Calendar Alarm Register RTC_CALALR Read-write 0x01010000 0x18 Status Register RTC_SR Read-only 0x0 0x1C Status Clear Command Register RTC_SCCR Write-only – 0x20 Interrupt Enable Register RTC_IER Write-only – 0x24 Interrupt Disable Register RTC_IDR Write-only – 0x28 Interrupt Mask Register RTC_IMR Read-only 0x0 0x2C Valid Entry Register RTC_VER Read-only 0x0 0x30–0xE0 Reserved Register – – – RTC_WPMR Read-write 0x00000000 0xE4 Write Protect Mode Register 0xE8–0xF8 Reserved Register – – – 0xFC Reserved Register – – – Note: if an offset is not listed in the table it must be considered as reserved. 250 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17.5.1 RTC Control Register Name: RTC_CR Address: 0x400E1260 Access: Read-write 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 – – – – – – 15 14 13 12 11 10 – – – – – – 16 CALEVSEL 9 8 TIMEVSEL 7 6 5 4 3 2 1 0 – – – – – – UPDCAL UPDTIM This register can only be written if the WPEN bit is cleared in “RTC Write Protect Mode Register” on page 263. • UPDTIM: Update Request Time Register 0 = No effect. 1 = Stops the RTC time counting. Time counting consists of second, minute and hour counters. Time counters can be programmed once this bit is set and acknowledged by the bit ACKUPD of the Status Register. • UPDCAL: Update Request Calendar Register 0 = No effect. 1 = Stops the RTC calendar counting. Calendar counting consists of day, date, month, year and century counters. Calendar counters can be programmed once this bit is set. • TIMEVSEL: Time Event Selection The event that generates the flag TIMEV in RTC_SR (Status Register) depends on the value of TIMEVSEL. Value Name Description 0 MINUTE Minute change 1 HOUR Hour change 2 MIDNIGHT Every day at midnight 3 NOON Every day at noon • CALEVSEL: Calendar Event Selection The event that generates the flag CALEV in RTC_SR depends on the value of CALEVSEL Value Name Description 0 WEEK Week change (every Monday at time 00:00:00) 1 MONTH Month change (every 01 of each month at time 00:00:00) 2 YEAR Year change (every January 1 at time 00:00:00) 3 – SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 251 17.5.2 RTC Mode Register Name: RTC_MR Address: 0x400E1264 Access: Read-write 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 – – – – – – – HRMOD • HRMOD: 12-/24-hour Mode 0 = 24-hour mode is selected. 1 = 12-hour mode is selected. All non-significant bits read zero. 252 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17.5.3 RTC Time Register Name: RTC_TIMR Address: 0x400E1268 Access: Read-write 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – AMPM 15 14 10 9 8 2 1 0 HOUR 13 12 – 7 11 MIN 6 5 – 4 3 SEC • SEC: Current Second The range that can be set is 0 - 59 (BCD). The lowest four bits encode the units. The higher bits encode the tens. • MIN: Current Minute The range that can be set is 0 - 59 (BCD). The lowest four bits encode the units. The higher bits encode the tens. • HOUR: Current Hour The range that can be set is 1 - 12 (BCD) in 12-hour mode or 0 - 23 (BCD) in 24-hour mode. • AMPM: Ante Meridiem Post Meridiem Indicator This bit is the AM/PM indicator in 12-hour mode. 0 = AM. 1 = PM. All non-significant bits read zero. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 253 17.5.4 RTC Calendar Register Name: RTC_CALR Address: 0x400E126C Access: Read-write 31 30 – – 23 22 29 28 27 21 20 19 DAY 15 14 26 25 24 18 17 16 DATE MONTH 13 12 11 10 9 8 3 2 1 0 YEAR 7 6 5 – 4 CENT • CENT: Current Century The range that can be set is 19 - 20 (BCD). The lowest four bits encode the units. The higher bits encode the tens. • YEAR: Current Year The range that can be set is 00 - 99 (BCD). The lowest four bits encode the units. The higher bits encode the tens. • MONTH: Current Month The range that can be set is 01 - 12 (BCD). The lowest four bits encode the units. The higher bits encode the tens. • DAY: Current Day in Current Week The range that can be set is 1 - 7 (BCD). The coding of the number (which number represents which day) is user-defined as it has no effect on the date counter. • DATE: Current Day in Current Month The range that can be set is 01 - 31 (BCD). The lowest four bits encode the units. The higher bits encode the tens. All non-significant bits read zero. 254 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17.5.5 RTC Time Alarm Register Name: RTC_TIMALR Address: 0x400E1270 Access: Read-write 31 30 29 28 27 26 25 24 – – – – – – – – 21 20 19 18 17 16 10 9 8 2 1 0 23 22 HOUREN AMPM 15 14 HOUR 13 12 MINEN 7 11 MIN 6 5 SECEN 4 3 SEC This register can only be written if the WPEN bit is cleared in “RTC Write Protect Mode Register” on page 263. • SEC: Second Alarm This field is the alarm field corresponding to the BCD-coded second counter. • SECEN: Second Alarm Enable 0 = The second-matching alarm is disabled. 1 = The second-matching alarm is enabled. • MIN: Minute Alarm This field is the alarm field corresponding to the BCD-coded minute counter. • MINEN: Minute Alarm Enable 0 = The minute-matching alarm is disabled. 1 = The minute-matching alarm is enabled. • HOUR: Hour Alarm This field is the alarm field corresponding to the BCD-coded hour counter. • AMPM: AM/PM Indicator This field is the alarm field corresponding to the BCD-coded hour counter. • HOUREN: Hour Alarm Enable 0 = The hour-matching alarm is disabled. 1 = The hour-matching alarm is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 255 17.5.6 RTC Calendar Alarm Register Name: RTC_CALALR Address: 0x400E1274 Access: Read-write 31 30 DATEEN – 29 28 27 26 25 24 18 17 16 DATE 23 22 21 MTHEN – – 20 19 15 14 13 12 11 10 9 8 – – – – – – – – MONTH 7 6 5 4 3 2 1 0 – – – – – – – – This register can only be written if the WPEN bit is cleared in “RTC Write Protect Mode Register” on page 263. • MONTH: Month Alarm This field is the alarm field corresponding to the BCD-coded month counter. • MTHEN: Month Alarm Enable 0 = The month-matching alarm is disabled. 1 = The month-matching alarm is enabled. • DATE: Date Alarm This field is the alarm field corresponding to the BCD-coded date counter. • DATEEN: Date Alarm Enable 0 = The date-matching alarm is disabled. 1 = The date-matching alarm is enabled. 256 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17.5.7 RTC Status Register Name: RTC_SR Address: 0x400E1278 Access: Read-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 – – – CALEV TIMEV SEC ALARM ACKUPD • ACKUPD: Acknowledge for Update 0 = Time and calendar registers cannot be updated. 1 = Time and calendar registers can be updated. • ALARM: Alarm Flag 0 = No alarm matching condition occurred. 1 = An alarm matching condition has occurred. • SEC: Second Event 0 = No second event has occurred since the last clear. 1 = At least one second event has occurred since the last clear. • TIMEV: Time Event 0 = No time event has occurred since the last clear. 1 = At least one time event has occurred since the last clear. The time event is selected in the TIMEVSEL field in RTC_CR (Control Register) and can be any one of the following events: minute change, hour change, noon, midnight (day change). • CALEV: Calendar Event 0 = No calendar event has occurred since the last clear. 1 = At least one calendar event has occurred since the last clear. The calendar event is selected in the CALEVSEL field in RTC_CR and can be any one of the following events: week change, month change and year change. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 257 17.5.8 RTC Status Clear Command Register Name: RTC_SCCR Address: 0x400E127C Access: Write-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 – – – CALCLR TIMCLR SECCLR ALRCLR ACKCLR • ACKCLR: Acknowledge Clear 0 = No effect. 1 = Clears corresponding status flag in the Status Register (RTC_SR). • ALRCLR: Alarm Clear 0 = No effect. 1 = Clears corresponding status flag in the Status Register (RTC_SR). • SECCLR: Second Clear 0 = No effect. 1 = Clears corresponding status flag in the Status Register (RTC_SR). • TIMCLR: Time Clear 0 = No effect. 1 = Clears corresponding status flag in the Status Register (RTC_SR). • CALCLR: Calendar Clear 0 = No effect. 1 = Clears corresponding status flag in the Status Register (RTC_SR). 258 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17.5.9 RTC Interrupt Enable Register Name: RTC_IER Address: 0x400E1280 Access: Write-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 – – – CALEN TIMEN SECEN ALREN ACKEN • ACKEN: Acknowledge Update Interrupt Enable 0 = No effect. 1 = The acknowledge for update interrupt is enabled. • ALREN: Alarm Interrupt Enable 0 = No effect. 1 = The alarm interrupt is enabled. • SECEN: Second Event Interrupt Enable 0 = No effect. 1 = The second periodic interrupt is enabled. • TIMEN: Time Event Interrupt Enable 0 = No effect. 1 = The selected time event interrupt is enabled. • CALEN: Calendar Event Interrupt Enable 0 = No effect. • 1 = The selected calendar event interrupt is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 259 17.5.10 RTC Interrupt Disable Register Name: RTC_IDR Address: 0x400E1284 Access: Write-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 – – – CALDIS TIMDIS SECDIS ALRDIS ACKDIS • ACKDIS: Acknowledge Update Interrupt Disable 0 = No effect. 1 = The acknowledge for update interrupt is disabled. • ALRDIS: Alarm Interrupt Disable 0 = No effect. 1 = The alarm interrupt is disabled. • SECDIS: Second Event Interrupt Disable 0 = No effect. 1 = The second periodic interrupt is disabled. • TIMDIS: Time Event Interrupt Disable 0 = No effect. 1 = The selected time event interrupt is disabled. • CALDIS: Calendar Event Interrupt Disable 0 = No effect. 1 = The selected calendar event interrupt is disabled. 260 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17.5.11 RTC Interrupt Mask Register Name: RTC_IMR Address: 0x400E1288 Access: Read-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 – – – CAL TIM SEC ALR ACK • ACK: Acknowledge Update Interrupt Mask 0 = The acknowledge for update interrupt is disabled. 1 = The acknowledge for update interrupt is enabled. • ALR: Alarm Interrupt Mask 0 = The alarm interrupt is disabled. 1 = The alarm interrupt is enabled. • SEC: Second Event Interrupt Mask 0 = The second periodic interrupt is disabled. 1 = The second periodic interrupt is enabled. • TIM: Time Event Interrupt Mask 0 = The selected time event interrupt is disabled. 1 = The selected time event interrupt is enabled. • CAL: Calendar Event Interrupt Mask 0 = The selected calendar event interrupt is disabled. 1 = The selected calendar event interrupt is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 261 17.5.12 RTC Valid Entry Register Name: RTC_VER Address: 0x400E128C Access: Read-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 – – – – NVCALALR NVTIMALR NVCAL NVTIM • NVTIM: Non-valid Time 0 = No invalid data has been detected in RTC_TIMR (Time Register). 1 = RTC_TIMR has contained invalid data since it was last programmed. • NVCAL: Non-valid Calendar 0 = No invalid data has been detected in RTC_CALR (Calendar Register). 1 = RTC_CALR has contained invalid data since it was last programmed. • NVTIMALR: Non-valid Time Alarm 0 = No invalid data has been detected in RTC_TIMALR (Time Alarm Register). 1 = RTC_TIMALR has contained invalid data since it was last programmed. • NVCALALR: Non-valid Calendar Alarm 0 = No invalid data has been detected in RTC_CALALR (Calendar Alarm Register). 1 = RTC_CALALR has contained invalid data since it was last programmed. 262 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 17.5.13 RTC Write Protect Mode Register Name: RTC_WPMR Address: 0x400E1344 Access: Read-write 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 WPKEY 23 22 21 20 WPKEY 15 14 13 12 WPKEY 7 6 5 4 3 2 1 0 — — — — — — — WPEN • WPEN: Write Protect Enable 0 = Disables the Write Protect if WPKEY corresponds to 0x525443 (“RTC” in ASCII). 1 = Enables the Write Protect if WPKEY corresponds to 0x525443 (“RTC” in ASCII). Protects the registers: “RTC Mode Register” on page 252 “RTC Time Alarm Register” on page 255 “RTC Calendar Alarm Register” on page 256 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 263 18. Supply Controller (SUPC) 18.1 Description The Supply Controller (SUPC) controls the supply voltage of the Core of the system and manages the Backup Low Power Mode. In this mode, the current consumption is reduced to a few microamps for Backup power retention. Exit from this mode is possible on multiple wake-up sources including events on FWUP or WKUP pins, or a Clock alarm. The SUPC also generates the Slow Clock by selecting either the Low Power RC oscillator or the Low Power Crystal oscillator. 18.2 264 Embedded Characteristics  Manages the Core Power Supply VDDCORE and the Backup Low Power Mode by Controlling the Embedded Voltage Regulator  Generates the Slow Clock SLCK, by Selecting Either the 22-42 kHz Low Power RC Oscillator or the 32 kHz Low Power Crystal Oscillator  Supports Multiple Wake Up Sources, for Exit from Backup Low Power Mode ̶ Force Wake Up Pin, with Programmable Debouncing ̶ 16 Wake Up Inputs, with Programmable Debouncing ̶ Real Time Clock Alarm ̶ Real Time Timer Alarm ̶ Supply Monitor Detection on VDDUTMI, with Programmable Scan Period and Voltage Threshold  A Supply Monitor Detection on VDDUTMI or a Brownout Detection on VDDCORE can Trigger a Core Reset  Embeds: ̶ One 22 to 42 kHz Low Power RC Oscillator ̶ One 32 kHz Low Power Crystal Oscillator ̶ One Zero-Power Power-On Reset Cell ̶ One Software Programmable Supply Monitor, on VDDUTMI Located in Backup Section ̶ One Brownout Detector on VDDCORE Located in the Core SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 18.3 Block Diagram Figure 18-1. Supply Controller Block Diagram VDDBU VDDIN vr_standby Software Controlled Voltage Regulator vr_vdd FWUP vr_deep VDDOUT SHDN WKUP0 - WKUP15 NRSTB Supply Controller VDDIO PIOA/B/C Input / Output Buffers Zero-Power Power-on Reset PIOx VDDANA General Purpose Backup Registers ADVREF ADC (front-end) ADx SLCK RTC rtc_alarm sm_in SLCK RTT VDDUTMI Supply Monitor sm_on rtt_alarm USBx USB osc32k_xtal_en VDDCORE vddcore_nreset XIN32 XOUT32 XTALSEL Xtal 32 kHz Oscillator Embedded 32 kHz RC Oscillator Slow Clock SLCK bodcore_on Brownout Detector bodcore_in supc_interrupt osc32k_rc_en SRAM Backup Power Supply Peripherals vddcore_nreset proc_nreset periph_nreset ice_nreset Reset Controller NRST Cortex-M3 Matrix Peripheral Bridge FSTT0 - FSTT15(1) Embedded 12 / 8 / 4 MHz RC Oscillator XIN XOUT Main Clock MAINCK 3 - 20 MHz XTAL Oscillator MAINCK PLLACK PLLA MAINCK Flash SLCK Power Management Controller Master Clock MCK SLCK Watchdog Timer UPLLCK UPLL Core Power Supply FSTT0 - FSTT15 are possible Fast Startup Sources, generated by WKUP0-WKUP15 Pins, but are not physical pins. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 265 18.4 Supply Controller Functional Description 18.4.1 Supply Controller Overview The device can be divided into two power supply areas:  The Backup VDDBU Power Supply: including the Supply Controller, a part of the Reset Controller, the Slow Clock switch, the General Purpose Backup Registers, the Supply Monitor and the Clock which includes the Real Time Timer and the Real Time Clock  The Core Power Supply: including the other part of the Reset Controller, the Brownout Detector, the Processor, the SRAM memory, the FLASH memory and the Peripherals The Supply Controller (SUPC) controls the supply voltage of the core power supply. The SUPC intervenes when the VDDUTMI power supply rises (when the system is starting) or when the Backup Low Power Mode is entered. The SUPC also integrates the Slow Clock generator which is based on a 32 kHz crystal oscillator and an embedded 32 kHz RC oscillator. The Slow Clock defaults to the RC oscillator, but the software can enable the crystal oscillator and select it as the Slow Clock source. The Supply Controller and the VDDUTMI power supply have a reset circuitry based on the NRSTB pin and a zeropower power-on reset cell. The zero-power power-on reset allows the SUPC to start properly as soon as the VDDUTMI voltage becomes valid. The NRSTB pin allows to reset the system from outside. At startup of the system, once the backup voltage VDDUTMI is valid and the reset pin NRSTB is not driven low and the embedded 32 kHz RC oscillator is stabilized, the SUPC starts up the core by sequentially enabling the internal Voltage Regulator, waiting that the core voltage VDDCORE is valid, then releasing the reset signal of the core “vddcore_nreset” signal. Once the system has started, the user can program a supply monitor and/or a brownout detector. If the supply monitor detects a voltage on VDDUTMI that is too low, the SUPC can assert the reset signal of the core “vddcore_nreset” signal until VDDUTMI is valid. Likewise, if the brownout detector detects a core voltage VDDCORE that is too low, the SUPC can assert the reset signal “vddcore_nreset” until VDDCORE is valid. When the Backup Low Power Mode is entered, the SUPC sequentially asserts the reset signal of the core power supply “vddcore_nreset” and disables the voltage regulator, in order to supply only the VDDUTMI power supply. In this mode the current consumption is reduced to a few microamps for Backup part retention. Exit from this mode is possible on multiple wake-up sources including an event on FWUP pin or WKUP pins, or a Clock alarm. To exit this mode, the SUPC operates in the same way as system startup. 266 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 18.4.2 Slow Clock Generator The Supply Controller embeds a slow clock generator that is supplied with the VDDUTMI power supply. As soon as the VDDUTMI is supplied, both the crystal oscillator and the embedded RC oscillator are powered up, but only the embedded RC oscillator is enabled. This allows the slow clock to be valid in a short time (about 100 µs). The user can select the crystal oscillator to be the source of the slow clock, as it provides a more accurate frequency. The command is made by writing the Supply Controller Control Register (SUPC_CR) with the XTALSEL bit at 1. This results in a sequence which first enables the crystal oscillator, then waits for 32,768 slow clock cycles, then switches the slow clock on the output of the crystal oscillator and then disables the RC oscillator to save power. The switch of the slow clock source is glitch free. The OSCSEL bit of the Supply Controller Status Register (SUPC_SR) allows knowing when the switch sequence is done. Coming back on the RC oscillator is only possible by shutting down the VDDUTMI power supply. If the user does not need the crystal oscillator, the XIN32 and XOUT32 pins should be left unconnected. The user can also set the crystal oscillator in bypass mode instead of connecting a crystal. In this case, the user has to provide the external clock signal on XIN32. The input characteristics of the XIN32 pin are given in the product electrical characteristics section. In order to set the bypass mode, the OSCBYPASS bit of the Supply Controller Mode Register (SUPC_MR) needs to be set at 1. 18.4.3 Voltage Regulator Control/Backup Low Power Mode The Supply Controller can be used to control the embedded 1.8V voltage regulator. The voltage regulator automatically adapts its quiescent current depending on the required load current. Please refer to the electrical characteristics section. The programmer can switch off the voltage regulator, and thus put the device in Backup mode, by writing the Supply Controller Control Register (SUPC_CR) with the VROFF bit at 1. This can be done also by using WFE (Wait for Event) Cortex-M3 instruction with the deep mode bit set to 1. The Backup mode can also be entered by executing the WFI (Wait for Interrupt) or WFE (Wait for Event) CortexM3 instructions. To select the Backup mode entry mechanism, two options are available, depending on the SLEEPONEXIT bit in the Cortex-M3 System Control register:  Sleep-now: if the SLEEPONEXIT bit is cleared, the device enters Backup mode as soon as the WFI or WFE instruction is executed.  Sleep-on-exit: if the SLEEPONEXIT bit is set when the WFI instruction is executed, the device enters Backup mode as soon as it exits the lowest priority ISR. This asserts the vddcore_nreset signal after the write resynchronization time which lasts, in the worse case, two slow clock cycles. Once the vddcore_nreset signal is asserted, the processor and the peripherals are stopped one slow clock cycle before the core power supply shuts off. 18.4.4 Using Backup Batteries/Backup Supply The product can be used with or without backup batteries, or more generally a backup supply. When a backup supply is used (See Figure 18-2), only VDDBU voltage is present in Backup mode and no other external supply is applied on the chip. In this case the user needs to clear VDDIORDY bit in the Supply Controller Mode Register (SUPC_MR) at least two slow clock periods before VDDIO voltage is removed. When waking up from Backup mode, the programmer needs to set VDDIORDY. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 267 Figure 18-2. Separated Backup Supply Powering Scheme FWUP SHDN Backup Batteries VDDBU VDDUTMI VDDANA VDDIO VDDIN Voltage Regulator Main Supply (1.8V-3.6V) VDDOUT VDDCORE VDDPLL Note: Restrictions: With Main Supply < 3V, some peripherals such as USB and ADC might not be operational. Refer to the DC Characteristics of the product for actual possible ranges for such peripherals. When a separated backup supply for VDDBU is not used (See Figure 18-3), since the external voltage applied on VDDIO is kept, all of the I/O configurations (i.e. WKUP pin configuration) are kept during backup mode. When not using backup batteries, VDDIORDY is set so the user does not need to program it. 268 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 18-3. No Separated Backup Supply Powering Scheme VDDBU VDDUTMI VDDANA VDDIO Main Supply (1.8V-3.6V) VDDIN Voltage Regulator VDDOUT VDDCORE VDDPLL Note: Restrictions: With Main Supply < 3V, some peripherals such as USB and ADC might not be operational. Refer to the DC Characteristics of the product for actual possible ranges for such peripherals. 18.4.5 Supply Monitor The Supply Controller embeds a supply monitor which is located in the VDDBU Backup Power Supply and which monitors VDDUTMI power supply. The supply monitor can be used to prevent the processor from falling into an unpredictable state if the Main power supply drops below a certain level. The threshold of the supply monitor is programmable. It can be selected from 1.9V to 3.4V by steps of 100 mV. This threshold is programmed in the SMTH field of the Supply Controller Supply Monitor Mode Register (SUPC_SMMR). The supply monitor can also be enabled during one slow clock period on every one of either 32, 256 or 2048 slow clock periods, according to the choice of the user. This can be configured by programming the SMSMPL field in SUPC_SMMR. Enabling the supply monitor for such reduced times allows to divide the typical supply monitor power consumption respectively by factors of 32, 256 or 2048, if the user does not need a continuous monitoring of the VDDUTMI power supply. A supply monitor detection can either generate a reset of the core power supply or a wake up of the core power supply. Generating a core reset when a supply monitor detection occurs is enabled by writing the SMRSTEN bit to 1 in SUPC_SMMR. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 269 Waking up the core power supply when a supply monitor detection occurs can be enabled by programming the SMEN bit to 1 in the Supply Controller Wake Up Mode Register (SUPC_WUMR). The Supply Controller provides two status bits in the Supply Controller Status Register for the supply monitor which allows to determine whether the last wake up was due to the supply monitor:  The SMOS bit provides real time information, which is updated at each measurement cycle or updated at each Slow Clock cycle, if the measurement is continuous.  The SMS bit provides saved information and shows a supply monitor detection has occurred since the last read of SUPC_SR. The SMS bit can generate an interrupt if the SMIEN bit is set to 1 in the Supply Controller Supply Monitor Mode Register (SUPC_SMMR). Figure 18-4. Supply Monitor Status Bit and Associated Interrupt Continuous Sampling (SMSMPL = 1) Periodic Sampling Supply Monitor ON 3.3 V Threshold 0V Read SUPC_SR SMS and SUPC interrupt 270 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 18.4.6 Backup Power Supply Reset 18.4.6.1 Raising the Backup Power Supply As soon as the backup voltage VDDUTMI rises, the RC oscillator is powered up and the zero-power power-on reset cell maintains its output low as long as VDDUTMI has not reached its target voltage. During this time, the Supply Controller is entirely reset. When the VDDUTMI voltage becomes valid and zero-power power-on reset signal is released, a counter is started for 5 slow clock cycles. This is the time it takes for the 32 kHz RC oscillator to stabilize. After this time, the SHDN pin is asserted and the voltage regulator is enabled. The core power supply rises and the brownout detector provides the bodcore_in signal as soon as the core voltage VDDCORE is valid. This results in releasing the vddcore_nreset signal to the Reset Controller after the bodcore_in signal has been confirmed as being valid for at least one slow clock cycle. Figure 18-5. Raising the VDDUTMI Power Supply 7 x Slow Clock Cycles Backup Power Supply TON Voltage Regulator 3 x Slow Clock Cycles 3 x Slow Clock Cycles 6.5 x Slow Clock Cycles Zero-Power POR Zero-Power Power-On Reset Cell output 22 - 42 kHz RC Oscillator output SHDN / vr_on Core Power Supply Fast RC Oscillator output bodcore_in vddcore_nreset NRST periph_nreset proc_nreset Note: After “proc_nreset” rising, the core starts fecthing instructions from Flash at 4 MHz. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 271 18.4.6.2 NRSTB Asynchronous Reset Pin The NRSTB pin is an asynchronous reset input, which acts exactly like the zero-power power-on reset cell. As soon as NRSTB is tied to GND, the supply controller is reset generating in turn, a reset of the whole system. When NRSTB is released, the system can start as described in Section 18.4.6.1 ”Raising the Backup Power Supply”. The NRSTB pin does not need to be driven during power-up phase to allow a reset of the system, it is done by the zero-power power-on cell. Figure 18-6. NRSTB Reset 30 Slow Clock Cycles = about 1ms between 2 and 3 Slow Clock Cycles NRSTB 32 kHz Low Power Crystal Oscillator output SHDN / vr_standby bodcore_in vddcore_nreset Note: periph_nreset, ice_reset and proc_nreset are not shown, but are asserted low thanks to the vddcore_nreset signal controlling the Reset controller. 18.4.6.3 SHDN output pin As shown in Figure 18-6, the SHDN pin acts like the vr_standby signal making it possible to use the SHDN pin to control external voltage regulator with shutdown capabilities. 18.4.7 Core Reset The Supply Controller manages the vddcore_nreset signal to the Reset Controller, as described previously in Section 18.4.6 ”Backup Power Supply Reset”. The vddcore_nreset signal is normally asserted before shutting down the core power supply and released as soon as the core power supply is correctly regulated. There are two additional sources which can be programmed to activate vddcore_nreset:  a supply monitor detection  a brownout detection 18.4.7.1 Supply Monitor Reset The supply monitor is capable of generating a reset of the system. This can be enabled by setting the SMRSTEN bit in the Supply Controller Supply Monitor Mode Register (SUPC_SMMR). If SMRSTEN is set and if a supply monitor detection occurs, the vddcore_nreset signal is immediately activated for a minimum of 1 slow clock cycle. 18.4.7.2 Brownout Detector Reset The brownout detector provides the bodcore_in signal to the SUPC which indicates that the voltage regulation is operating as programmed. If this signal is lost for longer than 1 slow clock period while the voltage regulator is enabled, the Supply Controller can assert vddcore_nreset. This feature is enabled by writing the bit, BODRSTEN (Brownout Detector Reset Enable) to 1 in the Supply Controller Mode Register (SUPC_MR). 272 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 If BODRSTEN is set and the voltage regulation is lost (output voltage of the regulator too low), the vddcore_nreset signal is asserted for a minimum of 1 slow clock cycle and then released if bodcore_in has been reactivated. The BODRSTS bit is set in the Supply Controller Status Register (SUPC_SR) so that the user can know the source of the last reset. Until bodcore_in is deactivated, the vddcore_nreset signal remains active. 18.4.8 Wake Up Sources The wake up events allow the device to exit backup mode. When a wake up event is detected, the Supply Controller performs a sequence which automatically reenables the core power supply. Figure 18-7. Wake Up Sources SMEN sm_int RTCEN rtc_alarm Core Supply Restart RTTEN rtt_alarm FWUPDBC SLCK FWUP FWUPEN FWUP WKUPT0 WKUP0 WKUPIS0 WKUPDBC WKUPEN1 WKUPIS1 WKUPS SLCK Debouncer Falling/Rising Edge Detector WKUPT15 WKUP15 WKUPEN0 Falling/Rising Edge Detector WKUPT1 WKUP1 Debouncer Falling Edge Detector WKUPEN15 WKUPIS15 Falling/Rising Edge Detector 18.4.8.1 Force Wake Up The FWUP pin is enabled as a wake up source by writing the FWUPEN bit to 1 in the Supply Controller Wake Up Mode Register (SUPC_WUMR). Then, the FWUPDBC field in the same register selects the debouncing period, which can be selected between 3, 32, 512, 4,096 or 32,768 slow clock cycles. This corresponds respectively to about 100 µs, about 1 ms, about 16 ms, about 128 ms and about 1 second (for a typical slow clock frequency of 32 kHz). Programming FWUPDBC to 0x0 selects an immediate wake up, i.e., the FWUP must be low during a minimum of one slow clock period to wake up the core power supply. If the FWUP pin is asserted for a time longer than the debouncing period, a wake up of the core power supply is started and the FWUP bit in the Supply Controller Status Register (SUPC_SR) is set and remains high until the register is read. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 273 18.4.8.2 Wake Up Inputs The wake up inputs, WKUP0 to WKUP15, can be programmed to perform a wake up of the core power supply. Each input can be enabled by writing to 1 the corresponding bit, WKUPEN0 to WKUPEN 15, in the Wake Up Inputs Register (SUPC_WUIR). The wake up level can be selected with the corresponding polarity bit, WKUPPL0 to WKUPPL15, also located in SUPC_WUIR. All the resulting signals are wired-ORed to trigger a debounce counter, which can be programmed with the WKUPDBC field in the Supply Controller Wake Up Mode Register (SUPC_WUMR). The WKUPDBC field can select a debouncing period of 3, 32, 512, 4,096 or 32,768 slow clock cycles. This corresponds respectively to about 100 µs, about 1 ms, about 16 ms, about 128 ms and about 1 second (for a typical slow clock frequency of 32 kHz). Programming WKUPDBC to 0x0 selects an immediate wake up, i.e., an enabled WKUP pin must be active according to its polarity during a minimum of one slow clock period to wake up the core power supply. If an enabled WKUP pin is asserted for a time longer than the debouncing period, a wake up of the core power supply is started and the signals, WKUP0 to WKUP15 as shown in Figure 18-7, are latched in the Supply Controller Status Register (SUPC_SR). This allows the user to identify the source of the wake up, however, if a new wake up condition occurs, the primary information is lost. No new wake up can be detected since the primary wake up condition has disappeared. 18.4.8.3 Clock Alarms The RTC and the RTT alarms can generate a wake up of the core power supply. This can be enabled by writing respectively, the bits RTCEN and RTTEN to 1 in the Supply Controller Wake Up Mode Register (SUPC_WUMR). The Supply Controller does not provide any status as the information is available in the User Interface of either the Real Time Timer or the Real Time Clock. 18.4.8.4 Supply Monitor Detection The supply monitor can generate a wakeup of the core power supply. See Section 18.4.5 ”Supply Monitor”. 274 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 18.5 Supply Controller (SUPC) User Interface The User Interface of the Supply Controller is part of the System Controller User Interface. 18.5.1 System Controller (SYSC) User Interface Table 18-1. System Controller Registers Offset System Controller Peripheral Name 0x00-0x0c Reset Controller RSTC 0x10-0x2C Supply Controller SUPC 0x30-0x3C Real Time Timer RTT 0x50-0x5C Watchdog Tiler WDT 0x60-0x7C Real Time Clock RTC 0x90-0xDC General Purpose Backup Register GPBR 18.5.2 Supply Controller (SUPC) User Interface Table 18-2. Register Mapping Offset Register Name Access Reset 0x00 Supply Controller Control Register SUPC_CR Write-only N/A 0x04 Supply Controller Supply Monitor Mode Register SUPC_SMMR Read-write 0x0000_0000 0x08 Supply Controller Mode Register SUPC_MR Read-write 0x0000_5A00 0x0C Supply Controller Wake Up Mode Register SUPC_WUMR Read-write 0x0000_0000 0x10 Supply Controller Wake Up Inputs Register SUPC_WUIR Read-write 0x0000_0000 0x14 Supply Controller Status Register SUPC_SR Read-only 0x0000_0800 0x18 Reserved SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 275 18.5.3 Supply Controller Control Register Name: SUPC_CR Address: 0x400E1210 Access: Write-only 31 30 29 28 27 26 25 24 KEY 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 8 – 7 – 6 – 5 – 4 – 3 XTALSEL 2 VROFF 1 – 0 – • VROFF: Voltage Regulator Off 0 (NO_EFFECT) = no effect. 1 (STOP_VREG) = if KEY is correct, asserts vddcore_nreset and stops the voltage regulator. • XTALSEL: Crystal Oscillator Select 0 (NO_EFFECT) = no effect. 1 (CRYSTAL_SEL) = if KEY is correct, switches the slow clock on the crystal oscillator output. • KEY: Password Should be written to value 0xA5. Writing any other value in this field aborts the write operation. 276 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 18.5.4 Supply Controller Supply Monitor Mode Register Name: SUPC_SMMR Address: 0x400E1214 Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 SMIEN 12 SMRSTEN 11 – 10 9 SMSMPL 8 7 – 6 – 5 – 4 – 3 2 1 0 SMTH • SMTH: Supply Monitor Threshold Value Name Description 0x0 1_9V 1.9 V 0x1 2_0V 2.0 V 0x2 2_1V 2.1 V 0x3 2_2V 2.2 V 0x4 2_3V 2.3 V 0x5 2_4V 2.4 V 0x6 2_5V 2.5 V 0x7 2_6V 2.6 V 0x8 2_7V 2.7 V 0x9 2_8V 2.8 V 0xA 2_9V 2.9 V 0xB 3_0V 3.0 V 0xC 3_1V 3.1 V 0xD 3_2V 3.2 V 0xE 3_3V 3.3 V 0xF 3_4V 3.4 V SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 277 • SMSMPL: Supply Monitor Sampling Period Value Name Description 0x0 SMD Supply Monitor disabled 0x1 CSM Continuous Supply Monitor 0x2 32SLCK Supply Monitor enabled one SLCK period every 32 SLCK periods 0x3 256SLCK Supply Monitor enabled one SLCK period every 256 SLCK periods 0x4 2048SLCK Supply Monitor enabled one SLCK period every 2,048 SLCK periods 0x5-0x7 Reserved Reserved • SMRSTEN: Supply Monitor Reset Enable 0 (NOT_ENABLE) = the core reset signal “vddcore_nreset” is not affected when a supply monitor detection occurs. 1 (ENABLE) = the core reset signal, vddcore_nreset is asserted when a supply monitor detection occurs. • SMIEN: Supply Monitor Interrupt Enable 0 (NOT_ENABLE) = the SUPC interrupt signal is not affected when a supply monitor detection occurs. 1 (ENABLE) = the SUPC interrupt signal is asserted when a supply monitor detection occurs. 278 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 18.5.5 Supply Controller Mode Register Name: SUPC_MR Address: 0x400E1218 Access: Read-write 31 30 29 28 27 26 25 24 KEY 23 – 22 – 21 – 20 OSCBYPASS 19 – 18 – 17 – 16 – 15 – 14 VDDIORDY 13 BODDIS 12 BODRSTEN 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 – • BODRSTEN: Brownout Detector Reset Enable 0 (NOT_ENABLE) = the core reset signal “vddcore_nreset” is not affected when a brownout detection occurs. 1 (ENABLE) = the core reset signal, vddcore_nreset is asserted when a brownout detection occurs. • BODDIS: Brownout Detector Disable 0 (ENABLE) = the core brownout detector is enabled. 1 (DISABLE) = the core brownout detector is disabled. • VDDIORDY: VDDIO Ready 0 (VDDIO_REMOVED) = VDDIO is removed (used before going to backup mode when backup batteries are used) 1 (VDDIO_PRESENT) = VDDIO is present (used before going to backup mode when backup batteries are used) If the backup batteries are not used, VDDIORDY must be kept set to 1. • OSCBYPASS: Oscillator Bypass 0 (NO_EFFECT) = no effect. Clock selection depends on XTALSEL value. 1 (BYPASS) = the 32-KHz XTAL oscillator is selected and is put in bypass mode. • KEY: Password Key Should be written to value 0xA5. Writing any other value in this field aborts the write operation. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 279 18.5.6 Supply Controller Wake Up Mode Register Name: SUPC_WUMR Address: 0x400E121C Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 13 WKUPDBC 12 11 – 10 9 FWUPDBC 8 7 – 6 – 5 – 4 – 3 RTCEN 2 RTTEN 1 SMEN 0 FWUPEN • FWUPEN: Force Wake Up Enable 0 (NOT_ENABLE) = the Force Wake Up pin has no wake up effect. 1 (ENABLE) = the Force Wake Up pin low forces the wake up of the core power supply. • SMEN: Supply Monitor Wake Up Enable 0 (NOT_ENABLE) = the supply monitor detection has no wake up effect. 1 (ENABLE) = the supply monitor detection forces the wake up of the core power supply. • RTTEN: Real Time Timer Wake Up Enable 0 (NOT_ENABLE) = the RTT alarm signal has no wake up effect. 1 (ENABLE) = the RTT alarm signal forces the wake up of the core power supply. • RTCEN: Real Time Clock Wake Up Enable 0 (NOT_ENABLE) = the RTC alarm signal has no wake up effect. 1 (ENABLE) = the RTC alarm signal forces the wake up of the core power supply. • FWUPDBC: Force Wake Up Debouncer Period 280 Value Name 0 IMMEDIATE 1 3_SCLK FWUP shall be low for at least 3 SLCK periods 2 32_SCLK FWUP shall be low for at least 32 SLCK periods 3 512_SCLK FWUP shall be low for at least 512 SLCK periods 4 4096_SCLK FWUP shall be low for at least 4,096 SLCK periods 5 32768_SCLK FWUP shall be low for at least 32,768 SLCK periods 6 Reserved Reserved 7 Reserved Reserved SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Description Immediate, no debouncing, detected active at least on one Slow Clock edge. • WKUPDBC: Wake Up Inputs Debouncer Period Value Name Description 0 IMMEDIATE 1 3_SCLK WKUPx shall be in its active state for at least 3 SLCK periods 2 32_SCLK WKUPx shall be in its active state for at least 32 SLCK periods 3 512_SCLK WKUPx shall be in its active state for at least 512 SLCK periods 4 4096_SCLK WKUPx shall be in its active state for at least 4,096 SLCK periods 5 32768_SCLK WKUPx shall be in its active state for at least 32,768 SLCK periods 6 Reserved Reserved 7 Reserved Reserved Immediate, no debouncing, detected active at least on one Slow Clock edge. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 281 18.5.7 System Controller Wake Up Inputs Register Name: SUPC_WUIR Address: 0x400E1220 Access: Read-write 31 WKUPT15 30 WKUPT14 29 WKUPT13 28 WKUPT12 27 WKUPT11 26 WKUPT10 25 WKUPT9 24 WKUPT8 23 WKUPT7 22 WKUPT6 21 WKUPT5 20 WKUPT4 19 WKUPT3 18 WKUPT2 17 WKUPT1 16 WKUPT0 15 WKUPEN15 14 WKUPEN14 13 WKUPEN13 12 WKUPEN12 11 WKUPEN11 10 WKUPEN10 9 WKUPEN9 8 WKUPEN8 7 WKUPEN7 6 WKUPEN6 5 WKUPEN5 4 WKUPEN4 3 WKUPEN3 2 WKUPEN2 1 WKUPEN1 0 WKUPEN0 • WKUPEN0 - WKUPEN15: Wake Up Input Enable 0 to 15 0 (NOT_ENABLE) = the corresponding wake-up input has no wake up effect. 1 (ENABLE) = the corresponding wake-up input forces the wake up of the core power supply. • WKUPT0 - WKUPT15: Wake Up Input Transition 0 to 15 0 (HIGH_TO_LOW) = a high to low level transition on the corresponding wake-up input forces the wake up of the core power supply. 1 (LOW_TO_HIGH) = a low to high level transition on the corresponding wake-up input forces the wake up of the core power supply. 282 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 18.5.8 Supply Controller Status Register Name: SUPC_SR Address: 0x400E1224 Access: Read-write 31 WKUPIS15 30 WKUPIS14 29 WKUPIS13 28 WKUPIS12 27 WKUPIS11 26 WKUPIS10 25 WKUPIS9 24 WKUPIS8 23 WKUPIS7 22 WKUPIS6 21 WKUPIS5 20 WKUPIS4 19 WKUPIS3 18 WKUPIS2 17 WKUPIS1 16 WKUPIS0 15 – 14 – 13 – 12 FWUPIS 11 – 10 – 9 – 8 – 7 OSCSEL 6 SMOS 5 SMS 4 SMRSTS 3 BODRSTS 2 SMWS 1 WKUPS 0 FWUPS Note: Because of the asynchronism between the Slow Clock (SCLK) and the System Clock (MCK), the status register flag reset is taken into account only 2 slow clock cycles after the read of the SUPC_SR. • FWUPS: FWUP Wake Up Status 0 (NO) = no wake up due to the assertion of the FWUP pin has occurred since the last read of SUPC_SR. 1 (PRESENT) = at least one wake up due to the assertion of the FWUP pin has occurred since the last read of SUPC_SR. • WKUPS: WKUP Wake Up Status 0 (NO) = no wake up due to the assertion of the WKUP pins has occurred since the last read of SUPC_SR. 1 (PRESENT) = at least one wake up due to the assertion of the WKUP pins has occurred since the last read of SUPC_SR. • SMWS: Supply Monitor Detection Wake Up Status 0 (NO) = no wake up due to a supply monitor detection has occurred since the last read of SUPC_SR. 1 (PRESENT) = at least one wake up due to a supply monitor detection has occurred since the last read of SUPC_SR. • BODRSTS: Brownout Detector Reset Status 0 (NO) = no core brownout rising edge event has been detected since the last read of the SUPC_SR. 1 (PRESENT) = at least one brownout output rising edge event has been detected since the last read of the SUPC_SR. When the voltage remains below the defined threshold, there is no rising edge event at the output of the brownout detection cell. The rising edge event occurs only when there is a voltage transition below the threshold. • SMRSTS: Supply Monitor Reset Status 0 (NO) = no supply monitor detection has generated a core reset since the last read of the SUPC_SR. 1 (PRESENT) = at least one supply monitor detection has generated a core reset since the last read of the SUPC_SR. • SMS: Supply Monitor Status 0 (NO) = no supply monitor detection since the last read of SUPC_SR. 1 (PRESENT) = at least one supply monitor detection since the last read of SUPC_SR. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 283 • SMOS: Supply Monitor Output Status 0 (HIGH) = the supply monitor detected VDDUTMI higher than its threshold at its last measurement. 1 (LOW) = the supply monitor detected VDDUTMI lower than its threshold at its last measurement. • OSCSEL: 32-kHz Oscillator Selection Status 0 (RC) = the slow clock, SLCK is generated by the embedded 32-kHz RC oscillator. 1 (CRYST) = the slow clock, SLCK is generated by the 32-kHz crystal oscillator. • FWUPIS: FWUP Input Status 0 (LOW) = FWUP input is tied low. 1 (HIGH) = FWUP input is tied high. • WKUPIS0-WKUPIS15: WKUP Input Status 0 to 15 0 (DIS) = the corresponding wake-up input is disabled, or was inactive at the time the debouncer triggered a wake up event. 1 (EN) = the corresponding wake-up input was active at the time the debouncer triggered a wake up event. 284 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 19. General Purpose Backup Registers (GPBR) 19.1 Embedded Characteristics  19.2 eight 32-bit General Purpose Backup Registers Description The System Controller embeds eight general-purpose backup registers. 19.2.1 Power Management Controller (PMC) User Interface Table 19-1. Offset 0x0 ... 0x1c Register Mapping Register Name General Purpose Backup Register 0 SYS_GPBR0 ... ... General Purpose Backup Register 7 SYS_GPBR7 Access Reset Read-write – ... ... Read-write – SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 285 19.2.1.1 General Purpose Backup Register x Name: SYS_GPBRx Address: 0x400E1290 [0] .. 0x400E12AC [7] Access: Read-write 31 30 29 28 27 26 25 24 18 17 16 10 9 8 2 1 0 GPBR_VALUEx 23 22 21 20 19 GPBR_VALUEx 15 14 13 12 11 GPBR_VALUEx 7 6 5 4 3 GPBR_VALUEx • GPBR_VALUEx: Value of GPBR x 286 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 20. Enhanced Embedded Flash Controller (EEFC) 20.1 Description The Enhanced Embedded Flash Controller (EEFC) ensures the interface of the Flash block with the 32-bit internal bus. Its 128-bit or 64-bit wide memory interface increases performance. It also manages the programming, erasing, locking and unlocking sequences of the Flash using a full set of commands. One of the commands returns the embedded Flash descriptor definition that informs the system about the Flash organization, thus making the software generic. 20.2 20.3 Embedded Characteristics  Interface of the Flash Block with the 32-bit Internal Bus  Increases Performance in Thumb2 Mode with 128-bit or -64 bit Wide Memory Interface up to 24 MHz  32 Lock Bits, Each Protecting a Lock Region  GPNVMx General-purpose GPNVM Bits  One-by-one Lock Bit Programming  Commands Protected by a Keyword  Erases the Entire Flash  Erases by Plane  Possibility of Erasing before Programming  Locking and Unlocking Operations  Consecutive Programming and Locking Operations Product Dependencies 20.3.1 Power Management The Enhanced Embedded Flash Controller (EEFC) is continuously clocked. The Power Management Controller has no effect on its behavior. 20.3.2 Interrupt Sources The Enhanced Embedded Flash Controller (EEFC) interrupt line is connected to the Nested Vectored Interrupt Controller (NVIC). Using the Enhanced Embedded Flash Controller (EEFC) interrupt requires the NVIC to be programmed first. The EEFC interrupt is generated only on FRDY bit rising. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 287 20.4 Functional Description 20.4.1 Embedded Flash Organization The embedded Flash interfaces directly with the 32-bit internal bus. The embedded Flash is composed of:  One memory plane organized in several pages of the same size.  Two 128-bit or 64-bit read buffers used for code read optimization.  One 128-bit or 64-bit read buffer used for data read optimization.  One write buffer that manages page programming. The write buffer size is equal to the page size. This buffer is write-only and accessible all along the 1 MByte address space, so that each word can be written to its final address.  Several lock bits used to protect write/erase operation on several pages (lock region). A lock bit is associated with a lock region composed of several pages in the memory plane.  Several bits that may be set and cleared through the Enhanced Embedded Flash Controller (EEFC) interface, called General Purpose Non Volatile Memory bits (GPNVM bits). The embedded Flash size, the page size, the lock regions organization and GPNVM bits definition are described in the product definition section. The Enhanced Embedded Flash Controller (EEFC) returns a descriptor of the Flash controlled after a get descriptor command issued by the application (see “Getting Embedded Flash Descriptor” on page 292). Figure 20-1. Embedded Flash Organization Memory Plane Start Address Page 0 Lock Region 0 Lock Bit 0 Lock Region 1 Lock Bit 1 Lock Region (n-1) Lock Bit (n-1) Page (m-1) Start Address + Flash size -1 288 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Page (n*m-1) 20.4.2 Read Operations An optimized controller manages embedded Flash reads, thus increasing performance when the processor is running in Thumb2 mode by means of the 128- or 64- bit wide memory interface. The Flash memory is accessible through 8-, 16- and 32-bit reads. As the Flash block size is smaller than the address space reserved for the internal memory area, the embedded Flash wraps around the address space and appears to be repeated within it. The read operations can be performed with or without wait states. Wait states must be programmed in the field FWS (Flash Read Wait State) in the Flash Mode Register (EEFC_FMR). Defining FWS to be 0 enables the singlecycle access of the embedded Flash. Refer to the Electrical Characteristics for more details. 20.4.2.1 128-bit or 64-bit Access Mode By default the read accesses of the Flash are performed through a 128-bit wide memory interface. It enables better system performance especially when 2 or 3 wait state needed. For systems requiring only 1 wait state, or to privilege current consumption rather than performance, the user can select a 64-bit wide memory access via the FAM bit in the Flash Mode Register (EEFC_FMR) Please refer to the electrical characteristics section of the product datasheet for more details. 20.4.2.2 Code Read Optimization A system of 2 x 128-bit or 2 x 64-bit buffers is added in order to optimize sequential Code Fetch. Note: Figure 20-2. Immediate consecutive code read accesses are not mandatory to benefit from this optimization. Code Read Optimization for FWS = 0 Master Clock ARM Request (32-bit) @Byte 0 Flash Access Buffer 0 (128bits) Buffer 1 (128bits) Data To ARM XXX @Byte 4 @Byte 8 Bytes 0-15 Bytes 16-31 XXX @Byte 12 @Byte 16 @Byte 20 @Byte 24 @Byte 32 Bytes 32-47 Bytes 32-47 Bytes 0-15 XXX Bytes 0-3 @Byte 28 Bytes 16-31 Bytes 4-7 Bytes 8-11 Bytes 12-15 Bytes 16-19 Bytes 20-23 Bytes 24-27 Bytes 28-31 Note: When FWS is equal to 0, all the accesses are performed in a single-cycle access. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 289 Figure 20-3. Code Read Optimization for FWS = 3 Master Clock ARM Request (32-bit) @Byte 0 @4 Flash Access @8 Bytes 0-15 @12 @16 @24 Bytes 16-31 XXX Buffer 0 (128bits) @20 @28 @32 @36 @40 Bytes 32-47 Bytes 32-47 XXX XXX @48 @52 Bytes 48-63 Bytes 0-15 Buffer 1 (128bits) Data To ARM @44 Bytes 16-31 0-3 4-7 8-11 12-15 16-19 20-23 24-27 28-31 32-35 36-39 40-43 44-47 48-51 Note: When FWS is included between 1 and 3, in case of sequential reads, the first access takes (FWS+1) cycles, the other ones only 1 cycle. 20.4.2.3 Data Read Optimization The organization of the Flash in 128 bits (or 64 bits) is associated with two 128-bit (or 64-bit) prefetch buffers and one 128-bit (or 64-bit) data read buffer, thus providing maximum system performance. This buffer is added in order to store the requested data plus all the data contained in the 128-bit (64-bit) aligned data. This speeds up sequential data reads if, for example, FWS is equal to 1 (see Figure 20-4). Note: Figure 20-4. No consecutive data read accesses are mandatory to benefit from this optimization. Data Read Optimization for FWS = 1 Master Clock ARM Request (32-bit) @Byte 0 @4 Flash Access XXX Buffer (128bits) Data To ARM 290 @8 @ 12 @ 16 Bytes 0-15 @ 24 @ 28 4-7 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 8-11 12-15 @ 36 Bytes 32-47 Bytes 0-15 Bytes 0-3 @ 32 Bytes 16-31 XXX XXX @ 20 Bytes 16-31 16-19 20-23 24-27 28-31 32-35 20.4.3 Flash Commands The Enhanced Embedded Flash Controller (EEFC) offers a set of commands such as programming the memory Flash, locking and unlocking lock regions, consecutive programming and locking and full Flash erasing, etc. Table 20-1. Set of Commands Command Value Mnemonic Get Flash Descriptor 0x00 GETD Write page 0x01 WP Write page and lock 0x02 WPL Erase page and write page 0x03 EWP Erase page and write page then lock 0x04 EWPL Erase all 0x05 EA Set Lock Bit 0x08 SLB Clear Lock Bit 0x09 CLB Get Lock Bit 0x0A GLB Set GPNVM Bit 0x0B SGPB Clear GPNVM Bit 0x0C CGPB Get GPNVM Bit 0x0D GGPB Start Read Unique Identifier 0x0E STUI Stop Read Unique Identifier 0x0F SPUI In order to perform one of these commands, the Flash Command Register (EEFC_FCR) has to be written with the correct command using the FCMD field. As soon as the EEFC_FCR register is written, the FRDY flag and the FVALUE field in the EEFC_FRR register are automatically cleared. Once the current command is achieved, then the FRDY flag is automatically set. If an interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the corresponding interrupt line of the NVIC is activated. (Note that this is true for all commands except for the STUI Command. The FRDY flag is not set when the STUI command is achieved.) All the commands are protected by the same keyword, which has to be written in the 8 highest bits of the EEFC_FCR register. Writing EEFC_FCR with data that does not contain the correct key and/or with an invalid command has no effect on the whole memory plane, but the FCMDE flag is set in the EEFC_FSR register. This flag is automatically cleared by a read access to the EEFC_FSR register. When the current command writes or erases a page in a locked region, the command has no effect on the whole memory plane, but the FLOCKE flag is set in the EEFC_FSR register. This flag is automatically cleared by a read access to the EEFC_FSR register. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 291 Figure 20-5. Command State Chart Read Status: MC_FSR No Check if FRDY flag Set Yes Write FCMD and PAGENB in Flash Command Register Read Status: MC_FSR No Check if FRDY flag Set Yes Check if FLOCKE flag Set Yes Locking region violation No Check if FCMDE flag Set Yes Bad keyword violation No Command Successfull 20.4.3.1 Getting Embedded Flash Descriptor This command allows the system to learn about the Flash organization. The system can take full advantage of this information. For instance, a device could be replaced by one with more Flash capacity, and so the software is able to adapt itself to the new configuration. To get the embedded Flash descriptor, the application writes the GETD command in the EEFC_FCR register. The first word of the descriptor can be read by the software application in the EEFC_FRR register as soon as the FRDY flag in the EEFC_FSR register rises. The next reads of the EEFC_FRR register provide the following word of the descriptor. If extra read operations to the EEFC_FRR register are done after the last word of the descriptor has been returned, then the EEFC_FRR register value is 0 until the next valid command. 292 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 20-2. Flash Descriptor Definition Symbol Word Index Description FL_ID 0 Flash Interface Description FL_SIZE 1 Flash size in bytes FL_PAGE_SIZE 2 Page size in bytes FL_NB_PLANE 3 Number of planes. FL_PLANE[0] 4 Number of bytes in the first plane. FL_PLANE[FL_NB_PLANE-1] 4 + FL_NB_PLANE - 1 Number of bytes in the last plane. FL_NB_LOCK 4 + FL_NB_PLANE Number of lock bits. A bit is associated with a lock region. A lock bit is used to prevent write or erase operations in the lock region. FL_LOCK[0] 4 + FL_NB_PLANE + 1 Number of bytes in the first lock region. ... ... 20.4.3.2 Write Commands Several commands can be used to program the Flash. Flash technology requires that an erase be done before programming. The full memory plane can be erased at the same time, or several pages can be erased at the same time (refer to Figure 20-6, "Example of Partial Page Programming", and the paragraph below the figure.). Also, a page erase can be automatically done before a page write using EWP or EWPL commands. After programming, the page (the whole lock region) can be locked to prevent miscellaneous write or erase sequences. The lock bit can be automatically set after page programming using WPL or EWPL commands. Data to be written are stored in an internal latch buffer. The size of the latch buffer corresponds to the page size. The latch buffer wraps around within the internal memory area address space and is repeated as many times as the number of pages within this address space. Note: Writing of 8-bit and 16-bit data is not allowed and may lead to unpredictable data corruption. Write operations are performed in a number of wait states equal to the number of wait states for read operations. Data are written to the latch buffer before the programming command is written to the Flash Command Register EEFC_FCR. The sequence is as follows:  Write the full page, at any page address, within the internal memory area address space.  Programming starts as soon as the page number and the programming command are written to the Flash Command Register. The FRDY bit in the Flash Programming Status Register (EEFC_FSR) is automatically cleared.  When programming is completed, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If an interrupt has been enabled by setting the bit FRDY in EEFC_FMR, the corresponding interrupt line of the NVIC is activated. Two errors can be detected in the EEFC_FSR register after a programming sequence:  Command Error: a bad keyword has been written in the EEFC_FCR register.  Lock Error: the page to be programmed belongs to a locked region. A command must be previously run to unlock the corresponding region. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 293 By using the WP command, a page can be programmed in several steps if it has been erased before (see Figure 20-6 below). Figure 20-6. Example of Partial Page Programming 32-bit wide X words X words FF FF FF FF FF FF FF FF FF FF X words FF FF FF FF FF X words 32-bit wide FF FF FF FF FF FF FF FF FF FF FF FF FF FF ... FF FF FF FF FF CA FE FF FF CA FE CA FE FF FF ... FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ... FF FF FF FF FF FF FF FF FF FF FF FF FF ... Step 1. Erase All Flash So Page Y erased ... ... ... ... 32-bit wide FF FF FF FF FF FF FF FF FF FF FF FF CA FE CA FE CA CA FE FE CA FE CA FE FF FF DE CA FF FF FF FF DE CA DE CA FF FF FF FF FF FF FF FF FF FF FF FF Step 2. Programming of the second part of Page Y FF ... FF FF FF CA FE CA CA FE FE FF FF ... ... DE CA DE CA DE CA ... FF FF FF FF FF FF Step 3. Programming of the third part of Page Y The Partial Programming mode works only with 128-bit (or higher) boundaries. It cannot be used with boundaries lower than 128 bits (8, 16 or 32-bit for example). 20.4.3.3 Erase Commands Erase commands are allowed only on unlocked regions. Depending on the Flash memory, several commands can be used to erase the Flash:  Erase all memory (EA): all memory is erased. The processor must not fetch code from the Flash memory. The erase sequence is:  Erase starts as soon as one of the erase commands and the FARG field are written in the Flash Command Register.  When the programming completes, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If an interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is activated. Two errors can be detected in the EEFC_FSR register after a programming sequence:  Command Error: a bad keyword has been written in the EEFC_FCR register.  Lock Error: at least one page to be erased belongs to a locked region. The erase command has been refused, no page has been erased. A command must be run previously to unlock the corresponding region. 20.4.3.4 Lock Bit Protection Lock bits are associated with several pages in the embedded Flash memory plane. This defines lock regions in the embedded Flash memory plane. They prevent writing/erasing protected pages. The lock sequence is: 294  The Set Lock command (SLB) and a page number to be protected are written in the Flash Command Register.  When the locking completes, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If an interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is activated. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15  If the lock bit number is greater than the total number of lock bits, then the command has no effect. The result of the SLB command can be checked running a GLB (Get Lock Bit) command. One error can be detected in the EEFC_FSR register after a programming sequence:  Command Error: a bad keyword has been written in the EEFC_FCR register. It is possible to clear lock bits previously set. Then the locked region can be erased or programmed. The unlock sequence is:  The Clear Lock command (CLB) and a page number to be unprotected are written in the Flash Command Register.  When the unlock completes, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If an interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is activated.  If the lock bit number is greater than the total number of lock bits, then the command has no effect. One error can be detected in the EEFC_FSR register after a programming sequence:  Command Error: a bad keyword has been written in the EEFC_FCR register. The status of lock bits can be returned by the Enhanced Embedded Flash Controller (EEFC). The Get Lock Bit status sequence is:  The Get Lock Bit command (GLB) is written in the Flash Command Register, FARG field is meaningless.  Lock bits can be read by the software application in the EEFC_FRR register. The first word read corresponds to the 32 first lock bits, next reads providing the next 32 lock bits as long as it is meaningful. Extra reads to the EEFC_FRR register return 0. For example, if the third bit of the first word read in the EEFC_FRR is set, then the third lock region is locked. One error can be detected in the EEFC_FSR register after a programming sequence:  Note: Command Error: a bad keyword has been written in the EEFC_FCR register. Access to the Flash in read is permitted when a set, clear or get lock bit command is performed. 20.4.3.5 GPNVM Bit GPNVM bits do not interfere with the embedded Flash memory plane. Refer to the product definition section for information on the GPNVM Bit Action. The set GPNVM bit sequence is:  Start the Set GPNVM Bit command (SGPB) by writing the Flash Command Register with the SGPB command and the number of the GPNVM bit to be set.  When the GPVNM bit is set, the bit FRDY in the Flash Programming Status Register (EEFC_FSR) rises. If an interrupt was enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is activated.  If the GPNVM bit number is greater than the total number of GPNVM bits, then the command has no effect. The result of the SGPB command can be checked by running a GGPB (Get GPNVM Bit) command. One error can be detected in the EEFC_FSR register after a programming sequence:  Command Error: a bad keyword has been written in the EEFC_FCR register. It is possible to clear GPNVM bits previously set. The clear GPNVM bit sequence is:  Start the Clear GPNVM Bit command (CGPB) by writing the Flash Command Register with CGPB and the number of the GPNVM bit to be cleared.  When the clear completes, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If an interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is activated.  If the GPNVM bit number is greater than the total number of GPNVM bits, then the command has no effect. One error can be detected in the EEFC_FSR register after a programming sequence:  Command Error: a bad keyword has been written in the EEFC_FCR register. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 295 The status of GPNVM bits can be returned by the Enhanced Embedded Flash Controller (EEFC). The sequence is:  Start the Get GPNVM bit command by writing the Flash Command Register with GGPB. The FARG field is meaningless.  GPNVM bits can be read by the software application in the EEFC_FRR register. The first word read corresponds to the 32 first GPNVM bits, following reads provide the next 32 GPNVM bits as long as it is meaningful. Extra reads to the EEFC_FRR register return 0. For example, if the third bit of the first word read in the EEFC_FRR is set, then the third GPNVM bit is active. One error can be detected in the EEFC_FSR register after a programming sequence:  Note: Command Error: a bad keyword has been written in the EEFC_FCR register. Access to the Flash in read is permitted when a set, clear or get GPNVM bit command is performed. 20.4.3.6 Security Bit Protection When the security is enabled, access to the Flash, either through the JTAG/SWD interface or through the Fast Flash Programming Interface, is forbidden. This ensures the confidentiality of the code programmed in the Flash. The security bit is GPNVM0. Disabling the security bit can only be achieved by asserting the ERASE pin at 1, and after a full Flash erase is performed. When the security bit is deactivated, all accesses to the Flash are permitted. 20.4.3.7 Unique Identifier Each part is programmed with a 128-bit Unique Identifier. It can be used to generate keys for example. To read the Unique Identifier the sequence is:  Send the Start Read unique Identifier command (STUI) by writing the Flash Command Register with the STUI command.  When the Unique Identifier is ready to be read, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) falls.  The Unique Identifier is located in the first 128 bits of the Flash memory mapping, thus, at the address 0x80000-0x8000F.  To stop the Unique Identifier mode, the user needs to send the Stop Read unique Identifier command (SPUI) by writing the Flash Command Register with the SPUI command.  When the Stop read Unique Identifier command (SPUI) has been performed, the FRDY bit in the Flash Programming Status Register (EEFC_FSR) rises. If an interrupt was enabled by setting the FRDY bit in EEFC_FMR, the interrupt line of the NVIC is activated. Note that during the sequence, the software can not run out of Flash (or the second plane in case of dual plane). 296 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 20.5 Enhanced Embedded Flash Controller (EEFC) User Interface The User Interface of the Enhanced Embedded Flash Controller (EEFC) is integrated within the System Controller with base address 0x400E0800. Table 20-3. Register Mapping Offset Register Name Access Reset State 0x00 EEFC Flash Mode Register EEFC_FMR Read-write 0x0 0x04 EEFC Flash Command Register EEFC_FCR Write-only – 0x08 EEFC Flash Status Register EEFC_FSR Read-only 0x00000001 0x0C EEFC Flash Result Register EEFC_FRR Read-only 0x0 0x10 Reserved – – – SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 297 20.5.1 EEFC Flash Mode Register Name: EEFC_FMR Address: 0x400E0800 (0), 0x400E0A00 (1) Access: Read-write Offset: 0x00 31 30 29 28 27 26 25 24 – – – – – – – FAM 23 22 21 20 19 18 17 16 – – – – – – – SCOD 15 14 13 12 11 10 9 8 – – – – 7 6 – FWS 5 4 3 2 1 0 – – – – – FRDY • FRDY: Ready Interrupt Enable 0: Flash Ready does not generate an interrupt. 1: Flash Ready (to accept a new command) generates an interrupt. • FWS: Flash Wait State This field defines the number of wait states for read and write operations: Number of cycles for Read/Write operations = FWS+1 • SCOD: Sequential Code Optimization Disable 0: The sequential code optimization is enabled. 1: The sequential code optimization is disabled. No Flash read should be done during change of this register. • FAM: Flash Access Mode 0: 128-bit access in read Mode only, to enhance access speed. 1: 64-bit access in read Mode only, to enhance power consumption. No Flash read should be done during change of this register. 298 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 20.5.2 EEFC Flash Command Register Name: EEFC_FCR Address: 0x400E0804 (0), 0x400E0A04 (1) Access: Write-only Offset: 0x04 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 FKEY 23 22 21 20 FARG 15 14 13 12 FARG 7 6 5 4 FCMD • FCMD: Flash Command This field defines the Flash commands. Refer to “Flash Commands” on page 291. • FARG: Flash Command Argument Erase all command Field is meaningless. Programming command FARG defines the page number to be programmed. Lock command FARG defines the page number to be locked. • FKEY: Flash Writing Protection Key This field should be written with the value 0x5A to enable the command defined by the bits of the register. If the field is written with a different value, the write is not performed and no action is started. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 299 20.5.3 EEFC Flash Status Register Name: EEFC_FSR Address: 0x400E0808 (0), 0x400E0A08 (1) Access: Read-only Offset: 0x08 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 – – – – – FLOCKE FCMDE FRDY • FRDY: Flash Ready Status 0: The Enhanced Embedded Flash Controller (EEFC) is busy. 1: The Enhanced Embedded Flash Controller (EEFC) is ready to start a new command. When it is set, this flags triggers an interrupt if the FRDY flag is set in the EEFC_FMR register. This flag is automatically cleared when the Enhanced Embedded Flash Controller (EEFC) is busy. • FCMDE: Flash Command Error Status 0: No invalid commands and no bad keywords were written in the Flash Mode Register EEFC_FMR. 1: An invalid command and/or a bad keyword was/were written in the Flash Mode Register EEFC_FMR. This flag is automatically cleared when EEFC_FSR is read or EEFC_FCR is written. • FLOCKE: Flash Lock Error Status 0: No programming/erase of at least one locked region has happened since the last read of EEFC_FSR. 1: Programming/erase of at least one locked region has happened since the last read of EEFC_FSR. This flag is automatically cleared when EEFC_FSR is read or EEFC_FCR is written. 300 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 20.5.4 EEFC Flash Result Register Name: EEFC_FRR Address: 0x400E080C (0), 0x400E0A0C (1) Access: Read-only Offset: 0x0C 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 FVALUE 23 22 21 20 FVALUE 15 14 13 12 FVALUE 7 6 5 4 FVALUE • FVALUE: Flash Result Value The result of a Flash command is returned in this register. If the size of the result is greater than 32 bits, then the next resulting value is accessible at the next register read. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 301 21. Fast Flash Programming Interface (FFPI) 21.1 Overview The Fast Flash Programming Interface provides solutions for high-volume programming using a standard gang programmer. The parallel interface is fully handshaked and the device is considered to be a standard EEPROM. Additionally, the parallel protocol offers an optimized access to all the embedded Flash functionalities. Although the Fast Flash Programming Mode is a dedicated mode for high volume programming, this mode is not designed for in-situ programming. 21.2 Parallel Fast Flash Programming 21.2.1 Device Configuration In Fast Flash Programming Mode, the device is in a specific test mode. Only a certain set of pins is significant. Other pins must be left unconnected. Figure 21-1. Parallel Programming Interface VDDBU TST VDDBU NRSTB VDDBU FWUP VDDIO VDDIN VDDANA PGMNCMD VDDUTMI RDY PGMRDY VDDPLL NOE PGMNOE NCMD NVALID PGMNVALID VDDCORE GND GNDBU MODE[3:0] PGMM[3:0] GNDANA DATA[15:0] PGMD[15:0] GNDPLL XIN GNDUTMI 0 - 50MHz (VDDCORE) 302 VDDBU SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 21-1. Signal Name Signal Description List Function Type Active Level Comments Power VDDIO I/O Lines Power Supply Power Apply external 3.0V-3.6V VDDBU Backup I/O Lines Power Supply Power Apply external 3.0V-3.6V VDDUTMI UTMI+ Interface Power Supply Power Apply external 3.0V-3.6V VDDANA ADC Analog Power Supply Power Apply external 3.0V-3.6V VDDIN Voltage Regulator Input Power Apply external 3.0V-3.6V VDDCORE Core Power Supply Power Apply external 1.65V-1.95V VDDPLL PLLs and Oscillator Power Supply Power Apply external 1.65V-1.95V GND Ground Ground GNDPLL Ground Ground GNDBU Ground Ground GNDANA Ground Ground GNDUTMI Ground Ground Clocks XIN Clock Input Input 0 to 50MHz (0-VDDCORE square wave) Test TST Test Mode Select Input High Must be connected to VDDIO NRSTB Asynchronous Microcontroller Reset Input High Must be connected to VDDIO FWUP Wake-up pin Input High Must be connected to VDDIO Input Low Pulled-up input at reset Output High Pulled-up input at reset Input Low Pulled-up input at reset Output Low Pulled-up input at reset PIO PGMNCMD PGMRDY PGMNOE PGMNVALID Valid command available 0: Device is busy 1: Device is ready for a new command Output Enable (active high) 0: DATA[15:0] is in input mode 1: DATA[15:0] is in output mode PGMM[3:0] Specifies DATA type (See Table 21-2) PGMD[15:0] Bi-directional data bus Input Pulled-up input at reset Input/Output Pulled-up input at reset SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 303 21.2.2 Signal Names Depending on the MODE settings, DATA is latched in different internal registers. Table 21-2. Mode Coding MODE[3:0] Symbol Data 0000 CMDE Command Register 0001 ADDR0 Address Register LSBs 0010 ADDR1 Address Register MSBs 0101 DATA Data Register Default IDLE No register When MODE is equal to CMDE, then a new command (strobed on DATA[15:0] signals) is stored in the command register. Table 21-3. Command Bit Coding DATA[15:0] Symbol Command Executed 0x0011 READ Read Flash 0x0012 WP Write Page Flash 0x0022 WPL Write Page and Lock Flash 0x0032 EWP Erase Page and Write Page 0x0042 EWPL Erase Page and Write Page then Lock 0x0013 EA Erase All 0x0014 SLB Set Lock Bit 0x0024 CLB Clear Lock Bit 0x0015 GLB Get Lock Bit 0x0034 SGPB Set General Purpose NVM bit 0x0044 CGPB Clear General Purpose NVM bit 0x0025 GGPB Get General Purpose NVM bit 0x0054 SSE Set Security Bit 0x0035 GSE Get Security Bit 0x001F WRAM Write Memory 0x0016 SEFC Select EEFC Controller(1) 0x001E GVE Get Version Note: 1. Applies to 256 kbytes Flash version (dual EEFC) 21.2.3 Entering Programming Mode The following algorithm puts the device in Parallel Programming Mode: 304  Apply GND, TST, NRTSB, FWUP and the supplies as described in Table 21-1, “Signal Description List,” on page 303.  Apply XIN clock  Wait for 20 ms  Start a read or write handshaking. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 21.2.4 Programmer Handshaking A handshake is defined for read and write operations. When the device is ready to start a new operation (RDY signal set), the programmer starts the handshake by clearing the NCMD signal. The handshaking is achieved once NCMD signal is high and RDY is high. 21.2.4.1 Write Handshaking For details on the write handshaking sequence, refer to Figure 21-2 and Table 21-4. Figure 21-2. Parallel Programming Timing, Write Sequence NCMD 2 4 3 RDY 5 NOE NVALID DATA[15:0] 1 MODE[3:0] Table 21-4. Write Handshake Step Programmer Action Device Action Data I/O 1 Sets MODE and DATA signals Waits for NCMD low Input 2 Clears NCMD signal Latches MODE and DATA Input 3 Waits for RDY low Clears RDY signal Input 4 Releases MODE and DATA signals Executes command and polls NCMD high Input 5 Sets NCMD signal Executes command and polls NCMD high Input 6 Waits for RDY high Sets RDY Input SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 305 21.2.4.2 Read Handshaking For details on the read handshaking sequence, refer to Figure 21-3 and Table 21-5. Figure 21-3. Parallel Programming Timing, Read Sequence NCMD 12 2 3 RDY 13 NOE 9 5 11 7 NVALID 6 4 DATA[15:0] Adress IN Z 8 10 Data OUT X IN 1 MODE[3:0] Table 21-5. ADDR Read Handshake Step Programmer Action Device Action DATA I/O 1 Sets MODE and DATA signals Waits for NCMD low Input 2 Clears NCMD signal Latch MODE and DATA Input 3 Waits for RDY low Clears RDY signal Input 4 Sets DATA signal in tristate Waits for NOE Low Input 5 Clears NOE signal 6 Waits for NVALID low 7 Tristate Sets DATA bus in output mode and outputs the flash contents. Output Clears NVALID signal Output Waits for NOE high Output 8 Reads value on DATA Bus 9 Sets NOE signal 10 Waits for NVALID high Sets DATA bus in input mode X 11 Sets DATA in output mode Sets NVALID signal Input 12 Sets NCMD signal Waits for NCMD high Input 13 Waits for RDY high Sets RDY signal Input Output 21.2.5 Device Operations Several commands on the Flash memory are available. These commands are summarized in Table 21-3 on page 304. Each command is driven by the programmer through the parallel interface running several read/write handshaking sequences. When a new command is executed, the previous one is automatically achieved. Thus, chaining a read command after a write automatically flushes the load buffer in the Flash. 306 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 21.2.5.1 Flash Read Command This command is used to read the contents of the Flash memory. The read command can start at any valid address in the memory plane and is optimized for consecutive reads. Read handshaking can be chained; an internal address buffer is automatically increased. Table 21-6. Read Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE READ 2 Write handshaking ADDR0 Memory Address LSB 3 Write handshaking ADDR1 Memory Address 4 Read handshaking DATA *Memory Address++ 5 Read handshaking DATA *Memory Address++ ... ... ... ... n Write handshaking ADDR0 Memory Address LSB n+1 Write handshaking ADDR1 Memory Address n+2 Read handshaking DATA *Memory Address++ n+3 Read handshaking DATA *Memory Address++ ... ... ... ... 21.2.5.2 Flash Write Command This command is used to write the Flash contents. The Flash memory plane is organized into several pages. Data to be written are stored in a load buffer that corresponds to a Flash memory page. The load buffer is automatically flushed to the Flash:  before access to any page other than the current one  when a new command is validated (MODE = CMDE) The Write Page command (WP) is optimized for consecutive writes. Write handshaking can be chained; an internal address buffer is automatically increased. Table 21-7. Write Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE WP or WPL or EWP or EWPL 2 Write handshaking ADDR0 Memory Address LSB 3 Write handshaking ADDR1 Memory Address 4 Write handshaking DATA *Memory Address++ 5 Write handshaking DATA *Memory Address++ ... ... ... ... n Write handshaking ADDR0 Memory Address LSB n+1 Write handshaking ADDR1 Memory Address n+2 Write handshaking DATA *Memory Address++ n+3 Write handshaking DATA *Memory Address++ ... ... ... ... The Flash command Write Page and Lock (WPL) is equivalent to the Flash Write Command. However, the lock bit is automatically set at the end of the Flash write operation. As a lock region is composed of several pages, the SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 307 programmer writes to the first pages of the lock region using Flash write commands and writes to the last page of the lock region using a Flash write and lock command. The Flash command Erase Page and Write (EWP) is equivalent to the Flash Write Command. However, before programming the load buffer, the page is erased. The Flash command Erase Page and Write the Lock (EWPL) combines EWP and WPL commands. 21.2.5.3 Flash Full Erase Command This command is used to erase the Flash memory planes. All lock regions must be unlocked before the Full Erase command by using the CLB command. Otherwise, the erase command is aborted and no page is erased. Table 21-8. Full Erase Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE EA 2 Write handshaking DATA 0 21.2.5.4 Flash Lock Commands Lock bits can be set using WPL or EWPL commands. They can also be set by using the Set Lock command (SLB). With this command, several lock bits can be activated. A Bit Mask is provided as argument to the command. When bit 0 of the bit mask is set, then the first lock bit is activated. Likewise, the Clear Lock command (CLB) is used to clear lock bits. Table 21-9. Set and Clear Lock Bit Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE SLB or CLB 2 Write handshaking DATA Bit Mask Lock bits can be read using Get Lock Bit command (GLB). The nth lock bit is active when the bit n of the bit mask is set.. Table 21-10. Get Lock Bit Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE GLB Lock Bit Mask Status 2 Read handshaking DATA 0 = Lock bit is cleared 1 = Lock bit is set 21.2.5.5 Flash General-purpose NVM Commands General-purpose NVM bits (GP NVM bits) can be set using the Set GPNVM command (SGPB). This command also activates GP NVM bits. A bit mask is provided as argument to the command. When bit 0 of the bit mask is set, then the first GP NVM bit is activated. Likewise, the Clear GPNVM command (CGPB) is used to clear general-purpose NVM bits. All the generalpurpose NVM bits are also cleared by the EA command. The general-purpose NVM bit is deactivated when the corresponding bit in the pattern value is set to 1. 308 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 21-11. Set/Clear GP NVM Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE SGPB or CGPB 2 Write handshaking DATA GP NVM bit pattern value General-purpose NVM bits can be read using the Get GPNVM Bit command (GGPB). The nth GP NVM bit is active when bit n of the bit mask is set.. Table 21-12. Get GP NVM Bit Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE GGPB GP NVM Bit Mask Status 2 Read handshaking DATA 0 = GP NVM bit is cleared 1 = GP NVM bit is set 21.2.5.6 Flash Security Bit Command A security bit can be set using the Set Security Bit command (SSE). Once the security bit is active, the Fast Flash programming is disabled. No other command can be run. An event on the Erase pin can erase the security bit once the contents of the Flash have been erased. The AT9SAM3U256 security bit is controlled by the EEFC0. To use the Set Security Bit command, the EEFC0 must be selected using the Select EFC command. Table 21-13. Set Security Bit Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE SSE 2 Write handshaking DATA 0 Once the security bit is set, it is not possible to access FFPI. The only way to erase the security bit is to erase the Flash. In order to erase the Flash, the user must perform the following:  Power-off the chip  Power-on the chip with TST = 0  Assert Erase during a period of more than 220 ms  Power-off the chip Then it is possible to return to FFPI mode and check that Flash is erased. 21.2.5.7 SAM3U 256 Kbytes Flash Select EEFC Command The commands WPx, EA, xLB, xFB are executed using the current EFC controller. The default EEFC controller is EEFC0. The Select EEFC command (SEFC) allows selection of the current EEFC controller. Table 21-14. Select EFC Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE SEFC 2 Write handshaking DATA 0 = Select EEFC0 1 = Select EEFC1 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 309 21.2.5.8 Memory Write Command This command is used to perform a write access to any memory location. The Memory Write command (WRAM) is optimized for consecutive writes. Write handshaking can be chained; an internal address buffer is automatically increased. Table 21-15. Write Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE WRAM 2 Write handshaking ADDR0 Memory Address LSB 3 Write handshaking ADDR1 Memory Address 4 Write handshaking DATA *Memory Address++ 5 Write handshaking DATA *Memory Address++ ... ... ... ... n Write handshaking ADDR0 Memory Address LSB n+1 Write handshaking ADDR1 Memory Address n+2 Write handshaking DATA *Memory Address++ n+3 Write handshaking DATA *Memory Address++ ... ... ... ... 21.2.5.9 Get Version Command The Get Version (GVE) command retrieves the version of the FFPI interface. Table 21-16. 310 Get Version Command Step Handshake Sequence MODE[3:0] DATA[15:0] 1 Write handshaking CMDE GVE 2 Write handshaking DATA Version SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 22. SAM3U4/2/1 Boot Program 22.1 Description The SAM-BA Boot Program integrates an array of programs permitting download and/or upload into the different memories of the product. 22.2 Flow Diagram The Boot Program implements the algorithm illustrated in Figure 22-1. Figure 22-1. Boot Program Algorithm Flow Diagram No No Device Setup USB Enumeration Successful ? Character # received from UART? Yes Yes Run SAM-BA Monitor Run SAM-BA Monitor The SAM-BA Boot program seeks to detect a source clock either from the embedded main oscillator with external crystal (main osccillator enabled) or from a 12 MHz signal applied to the XIN pin (main oscillator in Bypass mode). If a clock is found from the two possible sources above, the boot program checks to verify that the frequency is 12 MHz (taking into account the frequency range of the 32 kHz RC oscillator). If the frequency is 12 MHz, USB activation is allowed, else (no clock or frequency other than 12 MHz), the internal 12 MHz RC oscilator is used as main clock and USB clock is not allowed due to frequency drift of the 12 MHz RC oscillator. 22.3 Device Initialization The initialization sequence is the following: 1. Stack setup 2. Set up the Embedded Flash Controller 3. External Clock detection (quartz or external clock on XIN) 4. If quartz or external clock is 12 MHz, allow USB activation 5. Else, does not allow USB activation and use internal RC 12 MHz 6. Main oscillator frequency detection if no external clock detected 7. Switch Master Clock on Main Oscillator 8. C variable initialization 9. PLLA setup: PLLA is initialized to generate a 48 MHz clock 10. UPLL setup in case of USB activation allowed 11. Disable of the Watchdog 12. Initialization of the UART (115200 bauds, 8, N, 1) 13. Initialization of the USB Device Port (in case of USB activation allowed) 14. Wait for one of the following events: a. Check if USB device enumeration has occured b. Check if characters have been received in the UART 15. Jump to SAM-BA Monitor (see Section 22.4 ”SAM-BA Monitor”) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 311 22.4 SAM-BA Monitor Once the communication interface is identified, the monitor runs in an infinite loop waiting for different commands as shown in Table 22-1. Table 22-1. Command Action Argument(s) Example O write a byte Address, Value# O200001,CA# o read a byte Address,# o200001,# H write a half word Address, Value# H200002,CAFE# h read a half word Address,# h200002,# W write a word Address, Value# W200000,CAFEDECA# w read a word Address,# w200000,# S send a file Address,# S200000,# R receive a file Address, NbOfBytes# R200000,1234# G go Address# G200200# V display version No argument V#  Write commands: Write a byte (O), a halfword (H) or a word (W) to the target. ̶ ̶ ̶    ̶ Address: Address in hexadecimal ̶ Output: The byte, halfword or word read in hexadecimal following by ‘>’ Send a file (S): Send a file to a specified address ̶ Address: Address in hexadecimal ̶ Output: ‘>’. There is a time-out on this command which is reached when the prompt ‘>’ appears before the end of the command execution. Receive a file (R): Receive data into a file from a specified address ̶ ̶  Value: Byte, halfword or word to write in hexadecimal. Output: ‘>’. ̶  Address: Address in hexadecimal. Read commands: Read a byte (o), a halfword (h) or a word (w) from the target. Note: Address: Address in hexadecimal NbOfBytes: Number of bytes in hexadecimal to receive Output: ‘>’ Go (G): Jump to a specified address and execute the code ̶ Address: Address to jump in hexadecimal ̶ Output: ‘>’ Get Version (V): Return the SAM-BA boot version ̶ 312 Commands Available Through the SAM-BA Boot Output: ‘>’ SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 22.4.1 UART Serial Port Communication is performed through the UART initialized to 115200 Baud, 8, n, 1. The Send and Receive File commands use the Xmodem protocol to communicate. Any terminal performing this protocol can be used to send the application file to the target. The size of the binary file to send depends on the SRAM size embedded in the product. In all cases, the size of the binary file must be lower than the SRAM size because the Xmodem protocol requires some SRAM memory to work. See Section 22.5 ”Hardware and Software Constraints”. 22.4.2 Xmodem Protocol The Xmodem protocol supported is the 128-byte length block. This protocol uses a two-character CRC-16 to guarantee detection of a maximum bit error. Xmodem protocol with CRC is accurate provided both sender and receiver report successful transmission. Each block of the transfer looks like: in which: ̶ = 01 hex ̶ = binary number, starts at 01, increments by 1, and wraps 0FFH to 00H (not to 01) ̶ = 1’s complement of the blk#. ̶ = 2 bytes CRC16 Figure 22-2 shows a transmission using this protocol. Figure 22-2. Xmodem Transfer Example Host Device C SOH 01 FE Data[128] CRC CRC ACK SOH 02 FD Data[128] CRC CRC ACK SOH 03 FC Data[100] CRC CRC ACK EOT ACK SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 313 22.4.3 USB Device Port A 12.000 MHz Crystal (or 12.000 MHz external clock on XIN) is necessary to use the USB Device Port. The device uses the USB communication device class (CDC) drivers to take advantage of the installed PC RS-232 software to talk over the USB. The CDC class is implemented in all releases of Windows® beginning with Windows 98SE. The CDC document, available at www.usb.org, describes a way to implement devices such as ISDN modems and virtual COM ports. The Vendor ID (VID) is Atmel’s vendor ID 0x03EB. The product ID (PID) is 0x6124. These references are used by the host operating system to mount the correct driver. On Windows systems, the INF files contain the correspondence between vendor ID and product ID. For more details about VID/PID for End Product/Systems, please refer to the Vendor ID form available from the USB Implementers Forum on www.usb.org. Atmel provides an INF example to see the device as a new serial port and also provides another custom driver used by the SAM-BA application: atm6124.sys. Refer to the application note Basic USB Application (Atmel literature number 6123) available on www.atmel.com) for more details. 22.4.3.1 Enumeration Process The USB protocol is a master/slave protocol. This is the host that starts the enumeration sending requests to the device through the control endpoint. The device handles standard requests as defined in the USB Specification. Table 22-2. Handled Standard Requests Request Definition GET_DESCRIPTOR Returns the current device configuration value. SET_ADDRESS Sets the device address for all future device access. SET_CONFIGURATION Sets the device configuration. GET_CONFIGURATION Returns the current device configuration value. GET_STATUS Returns status for the specified recipient. SET_FEATURE Set or Enable a specific feature. CLEAR_FEATURE Clear or Disable a specific feature. The device also handles some class requests defined in the CDC class. Table 22-3. Handled Class Requests Request Definition SET_LINE_CODING Configures DTE rate, stop bits, parity and number of character bits. GET_LINE_CODING Requests current DTE rate, stop bits, parity and number of character bits. SET_CONTROL_LINE_STATE RS-232 signal used to tell the DCE device the DTE device is now present. Unhandled requests are STALLed. 314 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 22.4.3.2 Communication Endpoints There are two communication endpoints and endpoint 0 is used for the enumeration process. Endpoint 1 is a 64byte Bulk OUT endpoint and endpoint 2 is a 64-byte Bulk IN endpoint. SAM-BA Boot commands are sent by the host through endpoint 1. If required, the message is split by the host into several data payloads by the host driver. If the command requires a response, the host can send IN transactions to pick up the response. 22.4.4 In Application Programming (IAP) Feature The IAP feature is a function located in ROM that can be called by any software application. When called, this function sends the desired FLASH command to the EEFC and waits for the Flash to be ready (looping while the FRDY bit is not set in the EEFC_FSR). Since this function is executed from ROM, this allows Flash programming (such as sector write) to be done by code running in Flash. The IAP function entry point is retrieved by reading the NMI vector in ROM (0x00180008). This function takes one argument in parameter: the command to be sent to the EEFC. This function returns the value of the EEFC_FSR. IAP software code example: (unsigned int) (*IAP_Function)(unsigned long); void main (void){ unsigned unsigned unsigned unsigned long long long long FlashSectorNum = 200; // flash_cmd = 0; flash_status = 0; EFCIndex = 0; // 0:EEFC0, 1: EEFC1 /* Initialize the function pointer (retrieve function address from NMI vector) */ IAP_Function = ((unsigned long) (*)(unsigned long)) 0x00180008; /* Send your data to the sector here */ /* build the command to send to EEFC */ flash_cmd = (0x5A bit MREAD = 0 Set the internal address TWI_IADR = address Load transmit register TWI_THR = Data to send Write STOP command TWI_CR = STOP Read Status register No TXRDY = 1? Yes Read Status register TXCOMP = 1? No Yes Transfer finished 638 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 32-17. TWI Write Operation with Multiple Data Bytes with or without Internal Address BEGIN Set TWI clock (CLDIV, CHDIV, CKDIV) in TWI_CWGR (Needed only once) Set the Control register: - Master enable TWI_CR = MSEN + SVDIS Set the Master Mode register: - Device slave address - Internal address size (if IADR used) - Transfer direction bit Write ==> bit MREAD = 0 No Internal address size = 0? Set the internal address TWI_IADR = address Yes Load Transmit register TWI_THR = Data to send Read Status register TWI_THR = data to send No TXRDY = 1? Yes Data to send? Yes Write STOP Command TWI_CR = STOP Read Status register Yes No TXCOMP = 1? END SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 639 Figure 32-18. TWI Read Operation with Single Data Byte without Internal Address BEGIN Set TWI clock (CLDIV, CHDIV, CKDIV) in TWI_CWGR (Needed only once) Set the Control register: - Master enable TWI_CR = MSEN + SVDIS Set the Master Mode register: - Device slave address - Transfer direction bit Read ==> bit MREAD = 1 Start the transfer TWI_CR = START | STOP Read status register RXRDY = 1? No Yes Read Receive Holding Register Read Status register No TXCOMP = 1? Yes END 640 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 32-19. TWI Read Operation with Single Data Byte and Internal Address BEGIN Set TWI clock (CLDIV, CHDIV, CKDIV) in TWI_CWGR (Needed only once) Set the Control register: - Master enable TWI_CR = MSEN + SVDIS Set the Master Mode register: - Device slave address - Internal address size (IADRSZ) - Transfer direction bit Read ==> bit MREAD = 1 Set the internal address TWI_IADR = address Start the transfer TWI_CR = START | STOP Read Status register No RXRDY = 1? Yes Read Receive Holding register Read Status register No TXCOMP = 1? Yes END SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 641 Figure 32-20. TWI Read Operation with Multiple Data Bytes with or without Internal Address BEGIN Set TWI clock (CLDIV, CHDIV, CKDIV) in TWI_CWGR (Needed only once) Set the Control register: - Master enable TWI_CR = MSEN + SVDIS Set the Master Mode register: - Device slave address - Internal address size (if IADR used) - Transfer direction bit Read ==> bit MREAD = 1 Internal address size = 0? Set the internal address TWI_IADR = address Yes Start the transfer TWI_CR = START Read Status register RXRDY = 1? No Yes Read Receive Holding register (TWI_RHR) No Last data to read but one? Yes Stop the transfer TWI_CR = STOP Read Status register No RXRDY = 1? Yes Read Receive Holding register (TWI_RHR) Read status register TXCOMP = 1? Yes END 642 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 No 32.9 32.9.1 Multi-master Mode Definition More than one master may handle the bus at the same time without data corruption by using arbitration. Arbitration starts as soon as two or more masters place information on the bus at the same time, and stops (arbitration is lost) for the master that intends to send a logical one while the other master sends a logical zero. As soon as arbitration is lost by a master, it stops sending data and listens to the bus in order to detect a stop. When the stop is detected, the master who has lost arbitration may put its data on the bus by respecting arbitration. Arbitration is illustrated in Figure 32-22 on page 644. 32.9.2 Different Multi-master Modes Two multi-master modes may be distinguished: 1. TWI is considered as a Master only and will never be addressed. 2. Note: TWI may be either a Master or a Slave and may be addressed. In both Multi-master modes arbitration is supported. 32.9.2.1 TWI as Master Only In this mode, TWI is considered as a Master only (MSEN is always at one) and must be driven like a Master with the ARBLST (ARBitration Lost) flag in addition. If arbitration is lost (ARBLST = 1), the programmer must reinitiate the data transfer. If the user starts a transfer (ex.: DADR + START + W + Write in THR) and if the bus is busy, the TWI automatically waits for a STOP condition on the bus to initiate the transfer (see Figure 32-21 on page 644). Note: The state of the bus (busy or free) is not indicated in the user interface. 32.9.2.2 TWI as Master or Slave The automatic reversal from Master to Slave is not supported in case of a lost arbitration. Then, in the case where TWI may be either a Master or a Slave, the programmer must manage the pseudo Multimaster mode described in the steps below. 1. Program TWI in Slave mode (SADR + MSDIS + SVEN) and perform Slave Access (if TWI is addressed). 2. If TWI has to be set in Master mode, wait until TXCOMP flag is at 1. 3. Program Master mode (DADR + SVDIS + MSEN) and start the transfer (ex: START + Write in THR). 4. As soon as the Master mode is enabled, TWI scans the bus in order to detect if it is busy or free. When the bus is considered as free, TWI initiates the transfer. 5. As soon as the transfer is initiated and until a STOP condition is sent, the arbitration becomes relevant and the user must monitor the ARBLST flag. 6. If the arbitration is lost (ARBLST is set to 1), the user must program the TWI in Slave mode in the case where the Master that won the arbitration wanted to access the TWI. 7. If TWI has to be set in Slave mode, wait until TXCOMP flag is at 1 and then program the Slave mode. Note: In the case where the arbitration is lost and TWI is addressed, TWI will not acknowledge even if it is programmed in Slave mode as soon as ARBLST is set to 1. Then, the Master must repeat SADR. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 643 Figure 32-21. Programmer Sends Data While the Bus is Busy TWCK START sent by the TWI STOP sent by the master DATA sent by a master TWD DATA sent by the TWI Bus is busy Bus is free Transfer is kept TWI DATA transfer A transfer is programmed (DADR + W + START + Write THR) Bus is considered as free Transfer is initiated Figure 32-22. Arbitration Cases TWCK TWD TWCK Data from a Master S 1 0 0 1 1 Data from TWI S 1 0 1 TWD S 1 0 0 P Arbitration is lost TWI stops sending data 1 1 Data from the master P Arbitration is lost S 1 0 1 S 1 0 0 1 1 S 1 0 0 1 1 The master stops sending data Data from the TWI ARBLST Bus is busy Transfer is kept TWI DATA transfer A transfer is programmed (DADR + W + START + Write THR) Bus is free Transfer is stopped Transfer is programmed again (DADR + W + START + Write THR) Bus is considered as free Transfer is initiated The flowchart shown in Figure 32-23 on page 645 gives an example of read and write operations in Multi-master mode. 644 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 32-23. Multi-master Flowchart START Programm the SLAVE mode: SADR + MSDIS + SVEN Read Status Register SVACC = 1 ? Yes GACC = 1 ? No No No No SVREAD = 1 ? EOSACC = 1 ? TXRDY= 1 ? Yes Yes Yes No Write in TWI_THR TXCOMP = 1 ? No RXRDY= 1 ? Yes No No Yes Read TWI_RHR Need to perform a master access ? GENERAL CALL TREATMENT Yes Decoding of the programming sequence No Prog seq OK ? Change SADR Program the Master mode DADR + SVDIS + MSEN + CLK + R / W Read Status Register Yes No ARBLST = 1 ? Yes Yes No MREAD = 1 ? RXRDY= 0 ? TXRDY= 0 ? No No Read TWI_RHR Yes Yes Data to read? Data to send ? Yes Write in TWI_THR No No Stop Transfer TWI_CR = STOP Read Status Register Yes TXCOMP = 0 ? No SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 645 32.10 Slave Mode 32.10.1 Definition The Slave Mode is defined as a mode where the device receives the clock and the address from another device called the master. In this mode, the device never initiates and never completes the transmission (START, REPEATED_START and STOP conditions are always provided by the master). 32.10.2 Application Block Diagram Figure 32-24. Slave Mode Typical Application Block Diagram VDD R Master Host with TWI Interface R TWD TWCK Host with TWI Interface Host with TWI Interface LCD Controller Slave 1 Slave 2 Slave 3 32.10.3 Programming Slave Mode The following fields must be programmed before entering Slave mode: 1. SADR (TWI_SMR): The slave device address is used in order to be accessed by master devices in read or write mode. 2. MSDIS (TWI_CR): Disable the master mode. 3. SVEN (TWI_CR): Enable the slave mode. As the device receives the clock, values written in TWI_CWGR are not taken into account. 32.10.4 Receiving Data After a Start or Repeated Start condition is detected and if the address sent by the Master matches with the Slave address programmed in the SADR (Slave ADdress) field, SVACC (Slave ACCess) flag is set and SVREAD (Slave READ) indicates the direction of the transfer. SVACC remains high until a STOP condition or a repeated START is detected. When such a condition is detected, EOSACC (End Of Slave ACCess) flag is set. 32.10.4.1 Read Sequence In the case of a Read sequence (SVREAD is high), TWI transfers data written in the TWI_THR (TWI Transmit Holding Register) until a STOP condition or a REPEATED_START + an address different from SADR is detected. Note that at the end of the read sequence TXCOMP (Transmission Complete) flag is set and SVACC reset. As soon as data is written in the TWI_THR, TXRDY (Transmit Holding Register Ready) flag is reset, and it is set when the shift register is empty and the sent data acknowledged or not. If the data is not acknowledged, the NACK flag is set. Note that a STOP or a repeated START always follows a NACK. See Figure 32-25 on page 647. 646 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32.10.4.2 Write Sequence In the case of a Write sequence (SVREAD is low), the RXRDY (Receive Holding Register Ready) flag is set as soon as a character has been received in the TWI_RHR (TWI Receive Holding Register). RXRDY is reset when reading the TWI_RHR. TWI continues receiving data until a STOP condition or a REPEATED_START + an address different from SADR is detected. Note that at the end of the write sequence TXCOMP flag is set and SVACC reset. See Figure 32-26 on page 648. 32.10.4.3 Clock Synchronization Sequence In the case where TWI_THR or TWI_RHR is not written/read in time, TWI performs a clock synchronization. Clock stretching information is given by the SCLWS (Clock Wait state) bit. See Figure 32-28 on page 649 and Figure 32-29 on page 650. 32.10.4.4 General Call In the case where a GENERAL CALL is performed, GACC (General Call ACCess) flag is set. After GACC is set, it is up to the programmer to interpret the meaning of the GENERAL CALL and to decode the new address programming sequence. See Figure 32-27 on page 648. 32.10.5 Data Transfer 32.10.5.1 Read Operation The read mode is defined as a data requirement from the master. After a START or a REPEATED START condition is detected, the decoding of the address starts. If the slave address (SADR) is decoded, SVACC is set and SVREAD indicates the direction of the transfer. Until a STOP or REPEATED START condition is detected, TWI continues sending data loaded in the TWI_THR register. If a STOP condition or a REPEATED START + an address different from SADR is detected, SVACC is reset. Figure 32-25 on page 647 describes the write operation. Figure 32-25. Read Access Ordered by a MASTER SADR matches, TWI answers with an ACK SADR does not match, TWI answers with a NACK TWD S ADR R NA DATA NA P/S/Sr SADR R A DATA A ACK/NACK from the Master A DATA NA S/Sr TXRDY NACK Write THR Read RHR SVACC SVREAD SVREAD has to be taken into account only while SVACC is active EOSVACC Notes: 1. When SVACC is low, the state of SVREAD becomes irrelevant. 2. TXRDY is reset when data has been transmitted from TWI_THR to the shift register and set when this data has been acknowledged or non acknowledged. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 647 32.10.5.2 Write Operation The write mode is defined as a data transmission from the master. After a START or a REPEATED START, the decoding of the address starts. If the slave address is decoded, SVACC is set and SVREAD indicates the direction of the transfer (SVREAD is low in this case). Until a STOP or REPEATED START condition is detected, TWI stores the received data in the TWI_RHR register. If a STOP condition or a REPEATED START + an address different from SADR is detected, SVACC is reset. Figure 32-26 on page 648 describes the Write operation. Figure 32-26. Write Access Ordered by a Master SADR does not match, TWI answers with a NACK S TWD ADR W NA DATA NA SADR matches, TWI answers with an ACK P/S/Sr SADR W A DATA Read RHR A A DATA NA S/Sr RXRDY SVACC SVREAD has to be taken into account only while SVACC is active SVREAD EOSVACC Notes: 1. When SVACC is low, the state of SVREAD becomes irrelevant. 2. RXRDY is set when data has been transmitted from the shift register to the TWI_RHR and reset when this data is read. 32.10.5.3 General Call The general call is performed in order to change the address of the slave. If a GENERAL CALL is detected, GACC is set. After the detection of General Call, it is up to the programmer to decode the commands which come afterwards. In case of a WRITE command, the programmer has to decode the programming sequence and program a new SADR if the programming sequence matches. Figure 32-27 on page 648 describes the General Call access. Figure 32-27. Master Performs a General Call 0000000 + W TXD S GENERAL CALL RESET command = 00000110X WRITE command = 00000100X A Reset or write DADD A DATA1 A DATA2 A New SADR A P New SADR Programming sequence GCACC Reset after read SVACC Note: 648 This method allows the user to create an own programming sequence by choosing the programming bytes and the number of them. The programming sequence has to be provided to the master. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32.10.5.4 Clock Synchronization In both read and write modes, it may happen that TWI_THR/TWI_RHR buffer is not filled /emptied before the emission/reception of a new character. In this case, to avoid sending/receiving undesired data, a clock stretching mechanism is implemented. Clock Synchronization in Read Mode The clock is tied low if the shift register is empty and if a STOP or REPEATED START condition was not detected. It is tied low until the shift register is loaded. Figure 32-28 on page 649 describes the clock synchronization in Read mode. Figure 32-28. Clock Synchronization in Read Mode TWI_THR S SADR R DATA1 1 DATA0 A DATA0 A DATA1 DATA2 A XXXXXXX DATA2 NA S 2 TWCK Write THR CLOCK is tied low by the TWI as long as THR is empty SCLWS TXRDY SVACC SVREAD As soon as a START is detected TXCOMP TWI_THR is transmitted to the shift register Notes: Ack or Nack from the master 1 The data is memorized in TWI_THR until a new value is written 2 The clock is stretched after the ACK, the state of TWD is undefined during clock stretching 1. TXRDY is reset when data has been written in the TWI_THR to the shift register and set when this data has been acknowledged or non acknowledged. 2. At the end of the read sequence, TXCOMP is set after a STOP or after a REPEATED_START + an address different from SADR. 3. SCLWS is automatically set when the clock synchronization mechanism is started. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 649 Clock Synchronization in Write Mode The clock is tied low if the shift register and the TWI_RHR is full. If a STOP or REPEATED_START condition was not detected, it is tied low until TWI_RHR is read. Figure 32-29 on page 650 describes the clock synchronization in Read mode. Figure 32-29. Clock Synchronization in Write Mode TWCK CLOCK is tied low by the TWI as long as RHR is full TWD S SADR W A DATA0 TWI_RHR A DATA1 A DATA0 is not read in the RHR DATA2 DATA1 NA S ADR DATA2 SCLWS SCL is stretched on the last bit of DATA1 RXRDY Rd DATA0 Rd DATA1 Rd DATA2 SVACC SVREAD TXCOMP Notes: 650 As soon as a START is detected 1. At the end of the read sequence, TXCOMP is set after a STOP or after a REPEATED_START + an address different from SADR. 2. SCLWS is automatically set when the clock synchronization mechanism is started and automatically reset when the mechanism is finished. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32.10.5.5 Reversal after a Repeated Start Reversal of Read to Write The master initiates the communication by a read command and finishes it by a write command. Figure 32-30 on page 651 describes the repeated start + reversal from Read to Write mode. Figure 32-30. Repeated Start + Reversal from Read to Write Mode TWI_THR TWD DATA0 S SADR R A DATA0 DATA1 A DATA1 NA Sr SADR W A DATA2 TWI_RHR A DATA3 DATA2 A P DATA3 SVACC SVREAD TXRDY RXRDY EOSACC Cleared after read As soon as a START is detected TXCOMP 1. TXCOMP is only set at the end of the transmission because after the repeated start, SADR is detected again. Reversal of Write to Read The master initiates the communication by a write command and finishes it by a read command. Figure 32-31 on page 651 describes the repeated start + reversal from Write to Read mode. Figure 32-31. Repeated Start + Reversal from Write to Read Mode DATA2 TWI_THR TWD S SADR W A DATA0 TWI_RHR A DATA1 DATA0 A Sr SADR R A DATA3 DATA2 A DATA3 NA P DATA1 SVACC SVREAD TXRDY RXRDY EOSACC TXCOMP Notes: Read TWI_RHR Cleared after read As soon as a START is detected 1. In this case, if TWI_THR has not been written at the end of the read command, the clock is automatically stretched before the ACK. 2. TXCOMP is only set at the end of the transmission because after the repeated start, SADR is detected again. 32.10.6 Read Write Flowcharts The flowchart shown in Figure 32-32 on page 652 gives an example of read and write operations in Slave mode. A polling or interrupt method can be used to check the status bits. The interrupt method requires that the interrupt enable register (TWI_IER) be configured first. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 651 Figure 32-32. Read Write Flowchart in Slave Mode Set the SLAVE mode: SADR + MSDIS + SVEN Read Status Register SVACC = 1 ? No No EOSACC = 1 ? GACC = 1 ? No SVREAD = 0 ? TXRDY= 1 ? No Write in TWI_THR No TXCOMP = 1 ? RXRDY= 0 ? No END Read TWI_RHR GENERAL CALL TREATMENT Decoding of the programming sequence Prog seq OK ? Change SADR 652 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 No No 32.11 Two-wire Interface (TWI) User Interface Table 32-5. Register Mapping Offset Register Name Access Reset 0x00 Control Register TWI_CR Write-only N/A 0x04 Master Mode Register TWI_MMR Read-write 0x00000000 0x08 Slave Mode Register TWI_SMR Read-write 0x00000000 0x0C Internal Address Register TWI_IADR Read-write 0x00000000 0x10 Clock Waveform Generator Register TWI_CWGR Read-write 0x00000000 0x14 - 0x1C Reserved – – – 0x20 Status Register TWI_SR Read-only 0x0000F009 0x24 Interrupt Enable Register TWI_IER Write-only N/A 0x28 Interrupt Disable Register TWI_IDR Write-only N/A 0x2C Interrupt Mask Register TWI_IMR Read-only 0x00000000 0x30 Receive Holding Register TWI_RHR Read-only 0x00000000 Transmit Holding Register TWI_THR Write-only 0x00000000 – – – – – – 0x34 (1) 0xEC - 0xFC Reserved 0x100 - 0x124 Reserved for the PDC Note: 1. All unlisted offset values are considered as “reserved”. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 653 32.11.1 TWI Control Register Name: TWI_CR Address: 0x40084000 (0), 0x40088000 (1) Access: Write-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 SWRST 6 QUICK 5 SVDIS 4 SVEN 3 MSDIS 2 MSEN 1 STOP 0 START • START: Send a START Condition 0 = No effect. 1 = A frame beginning with a START bit is transmitted according to the features defined in the mode register. This action is necessary when the TWI peripheral wants to read data from a slave. When configured in Master Mode with a write operation, a frame is sent as soon as the user writes a character in the Transmit Holding Register (TWI_THR). • STOP: Send a STOP Condition 0 = No effect. 1 = STOP Condition is sent just after completing the current byte transmission in master read mode. – In single data byte master read, the START and STOP must both be set. – In multiple data bytes master read, the STOP must be set after the last data received but one. – In master read mode, if a NACK bit is received, the STOP is automatically performed. – In master data write operation, a STOP condition will be sent after the transmission of the current data is finished. • MSEN: TWI Master Mode Enabled 0 = No effect. 1 = If MSDIS = 0, the master mode is enabled. Note: Switching from Slave to Master mode is only permitted when TXCOMP = 1. • MSDIS: TWI Master Mode Disabled 0 = No effect. 1 = The master mode is disabled, all pending data is transmitted. The shifter and holding characters (if it contains data) are transmitted in case of write operation. In read operation, the character being transferred must be completely received before disabling. 654 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • SVEN: TWI Slave Mode Enabled 0 = No effect. 1 = If SVDIS = 0, the slave mode is enabled. Note: Switching from Master to Slave mode is only permitted when TXCOMP = 1. • SVDIS: TWI Slave Mode Disabled 0 = No effect. 1 = The slave mode is disabled. The shifter and holding characters (if it contains data) are transmitted in case of read operation. In write operation, the character being transferred must be completely received before disabling. • QUICK: SMBUS Quick Command 0 = No effect. 1 = If Master mode is enabled, a SMBUS Quick Command is sent. • SWRST: Software Reset 0 = No effect. 1 = Equivalent to a system reset. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 655 32.11.2 TWI Master Mode Register Name: TWI_MMR Address: 0x40084004 (0), 0x40088004 (1) Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 21 20 19 DADR 18 17 16 15 – 14 – 13 – 12 MREAD 11 – 10 – 9 8 7 – 6 – 5 – 4 – 3 – 2 – 1 – IADRSZ 0 – • IADRSZ: Internal Device Address Size Value Name Description 0 NONE No internal device address 1 1_BYTE One-byte internal device address 2 2_BYTE Two-byte internal device address 3 3_BYTE Three-byte internal device address • MREAD: Master Read Direction 0 = Master write direction. 1 = Master read direction. • DADR: Device Address The device address is used to access slave devices in read or write mode. Those bits are only used in Master mode. 656 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32.11.3 TWI Slave Mode Register Name: TWI_SMR Address: 0x40084008 (0), 0x40088008 (1) Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 21 20 19 SADR 18 17 16 15 – 14 – 13 – 12 – 11 – 10 – 9 8 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 – • SADR: Slave Address The slave device address is used in Slave mode in order to be accessed by master devices in read or write mode. SADR must be programmed before enabling the Slave mode or after a general call. Writes at other times have no effect. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 657 32.11.4 TWI Internal Address Register Name: TWI_IADR Address: 0x4008400C (0), 0x4008800C (1) Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 23 22 21 20 27 – 26 – 25 – 24 – 19 18 17 16 11 10 9 8 3 2 1 0 IADR 15 14 13 12 IADR 7 6 5 4 IADR • IADR: Internal Address 0, 1, 2 or 3 bytes depending on IADRSZ. 658 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32.11.5 TWI Clock Waveform Generator Register Name: TWI_CWGR Address: 0x40084010 (0), 0x40088010 (1) Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 22 21 20 19 18 17 CKDIV 16 15 14 13 12 11 10 9 8 3 2 1 0 CHDIV 7 6 5 4 CLDIV TWI_CWGR is only used in Master mode. • CLDIV: Clock Low Divider The SCL low period is defined as follows: T low = ( ( CLDIV × 2 CKDIV ) + 4 ) × T MCK • CHDIV: Clock High Divider The SCL high period is defined as follows: T high = ( ( CHDIV × 2 CKDIV ) + 4 ) × T MCK • CKDIV: Clock Divider The CKDIV is used to increase both SCL high and low periods. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 659 32.11.6 TWI Status Register Name: TWI_SR Address: 0x40084020 (0), 0x40088020 (1) Access: Read-only Reset: 0x0000F009 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 TXBUFE 14 RXBUFF 13 ENDTX 12 ENDRX 11 EOSACC 10 SCLWS 9 ARBLST 8 NACK 7 – 6 OVRE 5 GACC 4 SVACC 3 SVREAD 2 TXRDY 1 RXRDY 0 TXCOMP • TXCOMP: Transmission Completed (automatically set / reset) TXCOMP used in Master mode: 0 = During the length of the current frame. 1 = When both holding and shifter registers are empty and STOP condition has been sent. TXCOMP behavior in Master mode can be seen in Figure 32-8 on page 632 and in Figure 32-10 on page 633. TXCOMP used in Slave mode: 0 = As soon as a Start is detected. 1 = After a Stop or a Repeated Start + an address different from SADR is detected. TXCOMP behavior in Slave mode can be seen in Figure 32-28 on page 649, Figure 32-29 on page 650, Figure 32-30 on page 651 and Figure 32-31 on page 651. • RXRDY: Receive Holding Register Ready (automatically set / reset) 0 = No character has been received since the last TWI_RHR read operation. 1 = A byte has been received in the TWI_RHR since the last read. RXRDY behavior in Master mode can be seen in Figure 32-10 on page 633. RXRDY behavior in Slave mode can be seen in Figure 32-26 on page 648, Figure 32-29 on page 650, Figure 32-30 on page 651 and Figure 32-31 on page 651. • TXRDY: Transmit Holding Register Ready (automatically set / reset) TXRDY used in Master mode: 0 = The transmit holding register has not been transferred into shift register. Set to 0 when writing into TWI_THR register. 1 = As soon as a data byte is transferred from TWI_THR to internal shifter or if a NACK error is detected, TXRDY is set at the same time as TXCOMP and NACK. TXRDY is also set when MSEN is set (enable TWI). TXRDY behavior in Master mode can be seen in Figure 32-8 on page 632. TXRDY used in Slave mode: 0 = As soon as data is written in the TWI_THR, until this data has been transmitted and acknowledged (ACK or NACK). 1 = It indicates that the TWI_THR is empty and that data has been transmitted and acknowledged. 660 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 If TXRDY is high and if a NACK has been detected, the transmission will be stopped. Thus when TRDY = NACK = 1, the programmer must not fill TWI_THR to avoid losing it. TXRDY behavior in Slave mode can be seen in Figure 32-25 on page 647, Figure 32-28 on page 649, Figure 32-30 on page 651 and Figure 32-31 on page 651. • SVREAD: Slave Read (automatically set / reset) This bit is only used in Slave mode. When SVACC is low (no Slave access has been detected) SVREAD is irrelevant. 0 = Indicates that a write access is performed by a Master. 1 = Indicates that a read access is performed by a Master. SVREAD behavior can be seen in Figure 32-25 on page 647, Figure 32-26 on page 648, Figure 32-30 on page 651 and Figure 32-31 on page 651. • SVACC: Slave Access (automatically set / reset) This bit is only used in Slave mode. 0 = TWI is not addressed. SVACC is automatically cleared after a NACK or a STOP condition is detected. 1 = Indicates that the address decoding sequence has matched (A Master has sent SADR). SVACC remains high until a NACK or a STOP condition is detected. SVACC behavior can be seen in Figure 32-25 on page 647, Figure 32-26 on page 648, Figure 32-30 on page 651 and Figure 32-31 on page 651. • GACC: General Call Access (clear on read) This bit is only used in Slave mode. 0 = No General Call has been detected. 1 = A General Call has been detected. After the detection of General Call, if need be, the programmer may acknowledge this access and decode the following bytes and respond according to the value of the bytes. GACC behavior can be seen in Figure 32-27 on page 648. • OVRE: Overrun Error (clear on read) This bit is only used in Master mode. 0 = TWI_RHR has not been loaded while RXRDY was set 1 = TWI_RHR has been loaded while RXRDY was set. Reset by read in TWI_SR when TXCOMP is set. • NACK: Not Acknowledged (clear on read) NACK used in Master mode: 0 = Each data byte has been correctly received by the far-end side TWI slave component. 1 = A data byte has not been acknowledged by the slave component. Set at the same time as TXCOMP. NACK used in Slave Read mode: 0 = Each data byte has been correctly received by the Master. 1 = In read mode, a data byte has not been acknowledged by the Master. When NACK is set the programmer must not fill TWI_THR even if TXRDY is set, because it means that the Master will stop the data transfer or re initiate it. Note that in Slave Write mode all data are acknowledged by the TWI. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 661 • ARBLST: Arbitration Lost (clear on read) This bit is only used in Master mode. 0: Arbitration won. 1: Arbitration lost. Another master of the TWI bus has won the multi-master arbitration. TXCOMP is set at the same time. • SCLWS: Clock Wait State (automatically set / reset) This bit is only used in Slave mode. 0 = The clock is not stretched. 1 = The clock is stretched. TWI_THR / TWI_RHR buffer is not filled / emptied before the emission / reception of a new character. SCLWS behavior can be seen in Figure 32-28 on page 649 and Figure 32-29 on page 650. • EOSACC: End Of Slave Access (clear on read) This bit is only used in Slave mode. 0 = A slave access is being performing. 1 = The Slave Access is finished. End Of Slave Access is automatically set as soon as SVACC is reset. EOSACC behavior can be seen in Figure 32-30 on page 651 and Figure 32-31 on page 651 • ENDRX: End of RX buffer 0 = The Receive Counter Register has not reached 0 since the last write in TWI_RCR or TWI_RNCR. 1 = The Receive Counter Register has reached 0 since the last write in TWI_RCR or TWI_RNCR. • ENDTX: End of TX buffer 0 = The Transmit Counter Register has not reached 0 since the last write in TWI_TCR or TWI_TNCR. 1 = The Transmit Counter Register has reached 0 since the last write in TWI_TCR or TWI_TNCR. • RXBUFF: RX Buffer Full 0 = TWI_RCR or TWI_RNCR have a value other than 0. 1 = Both TWI_RCR and TWI_RNCR have a value of 0. • TXBUFE: TX Buffer Empty 0 = TWI_TCR or TWI_TNCR have a value other than 0. 1 = Both TWI_TCR and TWI_TNCR have a value of 0. 662 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32.11.7 TWI Interrupt Enable Register Name: TWI_IER Address: 0x40084024 (0), 0x40088024 (1) Access: Write-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 TXBUFE 14 RXBUFF 13 ENDTX 12 ENDRX 11 EOSACC 10 SCL_WS 9 ARBLST 8 NACK 7 – 6 OVRE 5 GACC 4 SVACC 3 – 2 TXRDY 1 RXRDY 0 TXCOMP • TXCOMP: Transmission Completed Interrupt Enable • RXRDY: Receive Holding Register Ready Interrupt Enable • TXRDY: Transmit Holding Register Ready Interrupt Enable • SVACC: Slave Access Interrupt Enable • GACC: General Call Access Interrupt Enable • OVRE: Overrun Error Interrupt Enable • NACK: Not Acknowledge Interrupt Enable • ARBLST: Arbitration Lost Interrupt Enable • SCL_WS: Clock Wait State Interrupt Enable • EOSACC: End Of Slave Access Interrupt Enable • ENDRX: End of Receive Buffer Interrupt Enable • ENDTX: End of Transmit Buffer Interrupt Enable • RXBUFF: Receive Buffer Full Interrupt Enable • TXBUFE: Transmit Buffer Empty Interrupt Enable 0 = No effect. 1 = Enables the corresponding interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 663 32.11.8 TWI Interrupt Disable Register Name: TWI_IDR Address: 0x40084028 (0), 0x40088028 (1) Access: Write-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 TXBUFE 14 RXBUFF 13 ENDTX 12 ENDRX 11 EOSACC 10 SCL_WS 9 ARBLST 8 NACK 7 – 6 OVRE 5 GACC 4 SVACC 3 – 2 TXRDY 1 RXRDY 0 TXCOMP • TXCOMP: Transmission Completed Interrupt Disable • RXRDY: Receive Holding Register Ready Interrupt Disable • TXRDY: Transmit Holding Register Ready Interrupt Disable • SVACC: Slave Access Interrupt Disable • GACC: General Call Access Interrupt Disable • OVRE: Overrun Error Interrupt Disable • NACK: Not Acknowledge Interrupt Disable • ARBLST: Arbitration Lost Interrupt Disable • SCL_WS: Clock Wait State Interrupt Disable • EOSACC: End Of Slave Access Interrupt Disable • ENDRX: End of Receive Buffer Interrupt Disable • ENDTX: End of Transmit Buffer Interrupt Disable • RXBUFF: Receive Buffer Full Interrupt Disable • TXBUFE: Transmit Buffer Empty Interrupt Disable 0 = No effect. 1 = Disables the corresponding interrupt. 664 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32.11.9 TWI Interrupt Mask Register Name: TWI_IMR Address: 0x4008402C (0), 0x4008802C (1) Access: Read-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 TXBUFE 14 RXBUFF 13 ENDTX 12 ENDRX 11 EOSACC 10 SCL_WS 9 ARBLST 8 NACK 7 – 6 OVRE 5 GACC 4 SVACC 3 – 2 TXRDY 1 RXRDY 0 TXCOMP • TXCOMP: Transmission Completed Interrupt Mask • RXRDY: Receive Holding Register Ready Interrupt Mask • TXRDY: Transmit Holding Register Ready Interrupt Mask • SVACC: Slave Access Interrupt Mask • GACC: General Call Access Interrupt Mask • OVRE: Overrun Error Interrupt Mask • NACK: Not Acknowledge Interrupt Mask • ARBLST: Arbitration Lost Interrupt Mask • SCL_WS: Clock Wait State Interrupt Mask • EOSACC: End Of Slave Access Interrupt Mask • ENDRX: End of Receive Buffer Interrupt Mask • ENDTX: End of Transmit Buffer Interrupt Mask • RXBUFF: Receive Buffer Full Interrupt Mask • TXBUFE: Transmit Buffer Empty Interrupt Mask 0 = The corresponding interrupt is disabled. 1 = The corresponding interrupt is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 665 32.11.10 TWI Receive Holding Register Name: TWI_RHR Address: 0x40084030 (0), 0x40088030 (1) Access: Read-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 6 5 4 3 2 1 0 RXDATA • RXDATA: Master or Slave Receive Holding Data 666 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 32.11.11 TWI Transmit Holding Register Name: TWI_THR Address: 0x40084034 (0), 0x40088034 (1) Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 6 5 4 3 2 1 0 TXDATA • TXDATA: Master or Slave Transmit Holding Data SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 667 33. Universal Asynchronous Receiver Transceiver (UART) 33.1 Description The Universal Asynchronous Receiver Transmitter features a two-pin UART that can be used for communication and trace purposes and offers an ideal medium for in-situ programming solutions. Moreover, the association with two peripheral DMA controller (PDC) channels permits packet handling for these tasks with processor time reduced to a minimum. 33.2 Embedded Characteristics  668 Two-pin UART ̶ Implemented Features are USART Compatible ̶ Independent Receiver and Transmitter with a Common Programmable Baud Rate Generator ̶ Even, Odd, Mark or Space Parity Generation ̶ Parity, Framing and Overrun Error Detection ̶ Automatic Echo, Local Loopback and Remote Loopback Channel Modes ̶ Interrupt Generation ̶ Support for Two PDC Channels with Connection to Receiver and Transmitter SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 33.3 Block Diagram Figure 33-1. UART Functional Block Diagram Peripheral Bridge Peripheral DMA Controller APB UART UTXD Transmit Power Management Controller Parallel Input/ Output Baud Rate Generator MCK Receive URXD Interrupt Control Table 33-1. UART Pin Description Pin Name Description Type URXD UART Receive Data Input UTXD UART Transmit Data Output 33.4 uart_irq Product Dependencies 33.4.1 I/O Lines The UART pins are multiplexed with PIO lines. The programmer must first configure the corresponding PIO Controller to enable I/O line operations of the UART. Table 33-2. I/O Lines Instance Signal I/O Line Peripheral UART URXD PA11 A UART UTXD PA12 A 33.4.2 Power Management The UART clock is controllable through the Power Management Controller. In this case, the programmer must first configure the PMC to enable the UART clock. Usually, the peripheral identifier used for this purpose is 1. 33.4.3 Interrupt Source The UART interrupt line is connected to one of the interrupt sources of the Nested Vectored Interrupt Controller (NVIC). Interrupt handling requires programming of the NVIC before configuring the UART. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 669 33.5 UART Operations The UART operates in asynchronous mode only and supports only 8-bit character handling (with parity). It has no clock pin. The UART is made up of a receiver and a transmitter that operate independently, and a common baud rate generator. Receiver timeout and transmitter time guard are not implemented. However, all the implemented features are compatible with those of a standard USART. 33.5.1 Baud Rate Generator The baud rate generator provides the bit period clock named baud rate clock to both the receiver and the transmitter. The baud rate clock is the master clock divided by 16 times the value (CD) written in UART_BRGR (Baud Rate Generator Register). If UART_BRGR is set to 0, the baud rate clock is disabled and the UART remains inactive. The maximum allowable baud rate is Master Clock divided by 16. The minimum allowable baud rate is Master Clock divided by (16 x 65536). MCK Baud Rate = ---------------------16 × CD Figure 33-2. Baud Rate Generator CD CD MCK 16-bit Counter OUT >1 1 0 Divide by 16 Baud Rate Clock 0 Receiver Sampling Clock 33.5.2 Receiver 33.5.2.1 Receiver Reset, Enable and Disable After device reset, the UART receiver is disabled and must be enabled before being used. The receiver can be enabled by writing the control register UART_CR with the bit RXEN at 1. At this command, the receiver starts looking for a start bit. The programmer can disable the receiver by writing UART_CR with the bit RXDIS at 1. If the receiver is waiting for a start bit, it is immediately stopped. However, if the receiver has already detected a start bit and is receiving the data, it waits for the stop bit before actually stopping its operation. The programmer can also put the receiver in its reset state by writing UART_CR with the bit RSTRX at 1. In doing so, the receiver immediately stops its current operations and is disabled, whatever its current state. If RSTRX is applied when data is being processed, this data is lost. 33.5.2.2 Start Detection and Data Sampling The UART only supports asynchronous operations, and this affects only its receiver. The UART receiver detects the start of a received character by sampling the URXD signal until it detects a valid start bit. A low level (space) on URXD is interpreted as a valid start bit if it is detected for more than 7 cycles of the sampling clock, which is 16 670 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 times the baud rate. Hence, a space that is longer than 7/16 of the bit period is detected as a valid start bit. A space which is 7/16 of a bit period or shorter is ignored and the receiver continues to wait for a valid start bit. When a valid start bit has been detected, the receiver samples the URXD at the theoretical midpoint of each bit. It is assumed that each bit lasts 16 cycles of the sampling clock (1-bit period) so the bit sampling point is eight cycles (0.5-bit period) after the start of the bit. The first sampling point is therefore 24 cycles (1.5-bit periods) after the falling edge of the start bit was detected. Each subsequent bit is sampled 16 cycles (1-bit period) after the previous one. Figure 33-3. Start Bit Detection Sampling Clock URXD True Start Detection D0 Baud Rate Clock Figure 33-4. Character Reception Example: 8-bit, parity enabled 1 stop 0.5 bit period 1 bit period URXD Sampling D0 D1 True Start Detection D2 D3 D4 D5 D6 Stop Bit D7 Parity Bit 33.5.2.3 Receiver Ready When a complete character is received, it is transferred to the UART_RHR and the RXRDY status bit in UART_SR (Status Register) is set. The bit RXRDY is automatically cleared when the receive holding register UART_RHR is read. Figure 33-5. URXD Receiver Ready S D0 D1 D2 D3 D4 D5 D6 D7 P S D0 D1 D2 D3 D4 D5 D6 D7 P RXRDY Read UART_RHR 33.5.2.4 Receiver Overrun If UART_RHR has not been read by the software (or the Peripheral Data Controller or DMA Controller) since the last transfer, the RXRDY bit is still set and a new character is received, the OVRE status bit in UART_SR is set. OVRE is cleared when the software writes the control register UART_CR with the bit RSTSTA (Reset Status) at 1. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 671 Figure 33-6. Receiver Overrun S URXD D0 D1 D2 D3 D4 D5 D6 D7 P stop D0 S D1 D2 D3 D4 D5 D6 D7 P stop RXRDY OVRE RSTSTA 33.5.2.5 Parity Error Each time a character is received, the receiver calculates the parity of the received data bits, in accordance with the field PAR in UART_MR. It then compares the result with the received parity bit. If different, the parity error bit PARE in UART_SR is set at the same time the RXRDY is set. The parity bit is cleared when the control register UART_CR is written with the bit RSTSTA (Reset Status) at 1. If a new character is received before the reset status command is written, the PARE bit remains at 1. Figure 33-7. Parity Error S URXD D0 D1 D2 D3 D4 D5 D6 D7 P stop RXRDY PARE Wrong Parity Bit RSTSTA 33.5.2.6 Receiver Framing Error When a start bit is detected, it generates a character reception when all the data bits have been sampled. The stop bit is also sampled and when it is detected at 0, the FRAME (Framing Error) bit in UART_SR is set at the same time the RXRDY bit is set. The FRAME bit remains high until the control register UART_CR is written with the bit RSTSTA at 1. Figure 33-8. Receiver Framing Error URXD S D0 D1 D2 D3 D4 D5 D6 D7 P stop RXRDY FRAME Stop Bit Detected at 0 RSTSTA 33.5.3 Transmitter 33.5.3.1 Transmitter Reset, Enable and Disable After device reset, the UART transmitter is disabled and it must be enabled before being used. The transmitter is enabled by writing the control register UART_CR with the bit TXEN at 1. From this command, the transmitter waits for a character to be written in the Transmit Holding Register (UART_THR) before actually starting the transmission. 672 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 The programmer can disable the transmitter by writing UART_CR with the bit TXDIS at 1. If the transmitter is not operating, it is immediately stopped. However, if a character is being processed into the Shift Register and/or a character has been written in the Transmit Holding Register, the characters are completed before the transmitter is actually stopped. The programmer can also put the transmitter in its reset state by writing the UART_CR with the bit RSTTX at 1. This immediately stops the transmitter, whether or not it is processing characters. 33.5.3.2 Transmit Format The UART transmitter drives the pin UTXD at the baud rate clock speed. The line is driven depending on the format defined in the Mode Register and the data stored in the Shift Register. One start bit at level 0, then the 8 data bits, from the lowest to the highest bit, one optional parity bit and one stop bit at 1 are consecutively shifted out as shown in the following figure. The field PARE in the mode register UART_MR defines whether or not a parity bit is shifted out. When a parity bit is enabled, it can be selected between an odd parity, an even parity, or a fixed space or mark bit. Figure 33-9. Character Transmission Example: Parity enabled Baud Rate Clock UTXD Start Bit D0 D1 D2 D3 D4 D5 D6 D7 Parity Bit Stop Bit 33.5.3.3 Transmitter Control When the transmitter is enabled, the bit TXRDY (Transmitter Ready) is set in the status register UART_SR. The transmission starts when the programmer writes in the Transmit Holding Register (UART_THR), and after the written character is transferred from UART_THR to the Shift Register. The TXRDY bit remains high until a second character is written in UART_THR. As soon as the first character is completed, the last character written in UART_THR is transferred into the shift register and TXRDY rises again, showing that the holding register is empty. When both the Shift Register and UART_THR are empty, i.e., all the characters written in UART_THR have been processed, the TXEMPTY bit rises after the last stop bit has been completed. Figure 33-10. Transmitter Control UART_THR Data 0 Data 1 Shift Register UTXD Data 0 S Data 0 Data 1 P stop S Data 1 P stop TXRDY TXEMPTY Write Data 0 in UART_THR Write Data 1 in UART_THR SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 673 33.5.4 Peripheral DMA Controller Both the receiver and the transmitter of the UART are connected to a Peripheral DMA Controller (PDC) channel. The peripheral data controller channels are programmed via registers that are mapped within the UART user interface from the offset 0x100. The status bits are reported in the UART status register (UART_SR) and can generate an interrupt. The RXRDY bit triggers the PDC channel data transfer of the receiver. This results in a read of the data in UART_RHR. The TXRDY bit triggers the PDC channel data transfer of the transmitter. This results in a write of data in UART_THR. 33.5.5 Test Modes The UART supports three test modes. These modes of operation are programmed by using the field CHMODE (Channel Mode) in the mode register (UART_MR). The Automatic Echo mode allows bit-by-bit retransmission. When a bit is received on the URXD line, it is sent to the UTXD line. The transmitter operates normally, but has no effect on the UTXD line. The Local Loopback mode allows the transmitted characters to be received. UTXD and URXD pins are not used and the output of the transmitter is internally connected to the input of the receiver. The URXD pin level has no effect and the UTXD line is held high, as in idle state. The Remote Loopback mode directly connects the URXD pin to the UTXD line. The transmitter and the receiver are disabled and have no effect. This mode allows a bit-by-bit retransmission. Figure 33-11. Test Modes Automatic Echo RXD Receiver Transmitter Disabled TXD Local Loopback Disabled Receiver RXD VDD Disabled Transmitter Remote Loopback TXD VDD Disabled RXD Receiver Disabled Transmitter 674 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 TXD 33.6 Universal Asynchronous Receiver Transceiver (UART) User Interface Table 33-3. Register Mapping Offset Register Name Access Reset 0x0000 Control Register UART_CR Write-only – 0x0004 Mode Register UART_MR Read-write 0x0 0x0008 Interrupt Enable Register UART_IER Write-only – 0x000C Interrupt Disable Register UART_IDR Write-only – 0x0010 Interrupt Mask Register UART_IMR Read-only 0x0 0x0014 Status Register UART_SR Read-only – 0x0018 Receive Holding Register UART_RHR Read-only 0x0 0x001C Transmit Holding Register UART_THR Write-only – 0x0020 Baud Rate Generator Register UART_BRGR Read-write 0x0 0x0024 - 0x003C Reserved – – – 0x004C - 0x00FC Reserved – – – 0x0100 - 0x0124 PDC Area – – – SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 675 33.6.1 UART Control Register Name: UART_CR Address: 0x400E0600 Access: Write-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – RSTSTA 7 6 5 4 3 2 1 0 TXDIS TXEN RXDIS RXEN RSTTX RSTRX – – • RSTRX: Reset Receiver 0 = No effect. 1 = The receiver logic is reset and disabled. If a character is being received, the reception is aborted. • RSTTX: Reset Transmitter 0 = No effect. 1 = The transmitter logic is reset and disabled. If a character is being transmitted, the transmission is aborted. • RXEN: Receiver Enable 0 = No effect. 1 = The receiver is enabled if RXDIS is 0. • RXDIS: Receiver Disable 0 = No effect. 1 = The receiver is disabled. If a character is being processed and RSTRX is not set, the character is completed before the receiver is stopped. • TXEN: Transmitter Enable 0 = No effect. 1 = The transmitter is enabled if TXDIS is 0. • TXDIS: Transmitter Disable 0 = No effect. 1 = The transmitter is disabled. If a character is being processed and a character has been written in the UART_THR and RSTTX is not set, both characters are completed before the transmitter is stopped. • RSTSTA: Reset Status Bits 0 = No effect. 1 = Resets the status bits PARE, FRAME and OVRE in the UART_SR. 676 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 33.6.2 UART Mode Register Name: UART_MR Address: 0x400E0604 Access: Read-write 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – CHMODE PAR – 7 6 5 4 3 2 1 0 – – – – – – – – • PAR: Parity Type Value Name Description 0 EVEN Even parity 1 ODD Odd parity 2 SPACE Space: parity forced to 0 3 MARK Mark: parity forced to 1 4 NO No parity • CHMODE: Channel Mode Value Name Description 0 NORMAL Normal Mode 1 AUTOMATIC Automatic Echo 2 LOCAL_LOOPBACK Local Loopback 3 REMOTE_LOOPBACK Remote Loopback SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 677 33.6.3 UART Interrupt Enable Register Name: UART_IER Address: 0x400E0608 Access: Write-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – RXBUFF TXBUFE – TXEMPTY – 7 6 5 4 3 2 1 0 PARE FRAME OVRE ENDTX ENDRX – TXRDY RXRDY • RXRDY: Enable RXRDY Interrupt • TXRDY: Enable TXRDY Interrupt • ENDRX: Enable End of Receive Transfer Interrupt • ENDTX: Enable End of Transmit Interrupt • OVRE: Enable Overrun Error Interrupt • FRAME: Enable Framing Error Interrupt • PARE: Enable Parity Error Interrupt • TXEMPTY: Enable TXEMPTY Interrupt • TXBUFE: Enable Buffer Empty Interrupt • RXBUFF: Enable Buffer Full Interrupt 0 = No effect. 1 = Enables the corresponding interrupt. 678 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 33.6.4 UART Interrupt Disable Register Name: UART_IDR Address: 0x400E060C Access: Write-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – RXBUFF TXBUFE – TXEMPTY – 7 6 5 4 3 2 1 0 PARE FRAME OVRE ENDTX ENDRX – TXRDY RXRDY • RXRDY: Disable RXRDY Interrupt • TXRDY: Disable TXRDY Interrupt • ENDRX: Disable End of Receive Transfer Interrupt • ENDTX: Disable End of Transmit Interrupt • OVRE: Disable Overrun Error Interrupt • FRAME: Disable Framing Error Interrupt • PARE: Disable Parity Error Interrupt • TXEMPTY: Disable TXEMPTY Interrupt • TXBUFE: Disable Buffer Empty Interrupt • RXBUFF: Disable Buffer Full Interrupt 0 = No effect. 1 = Disables the corresponding interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 679 33.6.5 UART Interrupt Mask Register Name: UART_IMR Address: 0x400E0610 Access: Read-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – RXBUFF TXBUFE – TXEMPTY – 7 6 5 4 3 2 1 0 PARE FRAME OVRE ENDTX ENDRX – TXRDY RXRDY • RXRDY: Mask RXRDY Interrupt • TXRDY: Disable TXRDY Interrupt • ENDRX: Mask End of Receive Transfer Interrupt • ENDTX: Mask End of Transmit Interrupt • OVRE: Mask Overrun Error Interrupt • FRAME: Mask Framing Error Interrupt • PARE: Mask Parity Error Interrupt • TXEMPTY: Mask TXEMPTY Interrupt • TXBUFE: Mask TXBUFE Interrupt • RXBUFF: Mask RXBUFF Interrupt 0 = The corresponding interrupt is disabled. 1 = The corresponding interrupt is enabled. 680 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 33.6.6 UART Status Register Name: UART_SR Address: 0x400E0614 Access: Read-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – RXBUFF TXBUFE – TXEMPTY – 7 6 5 4 3 2 1 0 PARE FRAME OVRE ENDTX ENDRX – TXRDY RXRDY • RXRDY: Receiver Ready 0 = No character has been received since the last read of the UART_RHR or the receiver is disabled. 1 = At least one complete character has been received, transferred to UART_RHR and not yet read. • TXRDY: Transmitter Ready 0 = A character has been written to UART_THR and not yet transferred to the Shift Register, or the transmitter is disabled. 1 = There is no character written to UART_THR not yet transferred to the Shift Register. • ENDRX: End of Receiver Transfer 0 = The End of Transfer signal from the receiver Peripheral Data Controller channel is inactive. 1 = The End of Transfer signal from the receiver Peripheral Data Controller channel is active. • ENDTX: End of Transmitter Transfer 0 = The End of Transfer signal from the transmitter Peripheral Data Controller channel is inactive. 1 = The End of Transfer signal from the transmitter Peripheral Data Controller channel is active. • OVRE: Overrun Error 0 = No overrun error has occurred since the last RSTSTA. 1 = At least one overrun error has occurred since the last RSTSTA. • FRAME: Framing Error 0 = No framing error has occurred since the last RSTSTA. 1 = At least one framing error has occurred since the last RSTSTA. • PARE: Parity Error 0 = No parity error has occurred since the last RSTSTA. 1 = At least one parity error has occurred since the last RSTSTA. • TXEMPTY: Transmitter Empty 0 = There are characters in UART_THR, or characters being processed by the transmitter, or the transmitter is disabled. 1 = There are no characters in UART_THR and there are no characters being processed by the transmitter. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 681 • TXBUFE: Transmission Buffer Empty 0 = The buffer empty signal from the transmitter PDC channel is inactive. 1 = The buffer empty signal from the transmitter PDC channel is active. • RXBUFF: Receive Buffer Full 0 = The buffer full signal from the receiver PDC channel is inactive. 1 = The buffer full signal from the receiver PDC channel is active. 682 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 33.6.7 UART Receiver Holding Register Name: UART_RHR Address: 0x400E0618 Access: Read-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 RXCHR • RXCHR: Received Character Last received character if RXRDY is set. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 683 33.6.8 UART Transmit Holding Register Name: UART_THR Address: 0x400E061C Access: Write-only 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 – – – – – – – – 7 6 5 4 3 2 1 0 TXCHR • TXCHR: Character to be Transmitted Next character to be transmitted after the current character if TXRDY is not set. 684 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 33.6.9 UART Baud Rate Generator Register Name: UART_BRGR Address: 0x400E0620 Access: Read-write 31 30 29 28 27 26 25 24 – – – – – – – – 23 22 21 20 19 18 17 16 – – – – – – – – 15 14 13 12 11 10 9 8 3 2 1 0 CD 7 6 5 4 CD • CD: Clock Divisor 0 = Baud Rate Clock is disabled 1 to 65,535 = MCK / (CD x 16) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 685 34. Universal Synchronous Asynchronous Receiver Transmitter (USART) 34.1 Description The Universal Synchronous Asynchronous Receiver Transceiver (USART) provides one full duplex universal synchronous asynchronous serial link. Data frame format is widely programmable (data length, parity, number of stop bits) to support a maximum of standards. The receiver implements parity error, framing error and overrun error detection. The receiver time-out enables handling variable-length frames and the transmitter timeguard facilitates communications with slow remote devices. Multidrop communications are also supported through address bit handling in reception and transmission. The USART features three test modes: remote loopback, local loopback and automatic echo. The USART supports specific operating modes providing interfaces on RS485 and SPI buses, with ISO7816 T = 0 or T = 1 smart card slots, infrared transceivers and connection to modem ports. The hardware handshaking feature enables an out-of-band flow control by automatic management of the pins RTS and CTS. The USART supports the connection to the Peripheral DMA Controller, which enables data transfers to the transmitter and from the receiver. The PDC provides chained buffer management without any intervention of the processor. 34.2 Embedded Characteristics  Programmable Baud Rate Generator  5- to 9-bit Full-duplex Synchronous or Asynchronous Serial Communications ̶ 1, 1.5 or 2 Stop Bits in Asynchronous Mode or 1 or 2 Stop Bits in Synchronous Mode ̶ Parity Generation and Error Detection ̶ Framing Error Detection, Overrun Error Detection ̶ MSB- or LSB-first ̶ Optional Break Generation and Detection ̶ By 8 or by 16 Over-sampling Receiver Frequency ̶ Optional Hardware Handshaking RTS-CTS ̶ Optional Modem Signal Management DTR-DSR-DCD-RI ̶ Receiver Time-out and Transmitter Timeguard ̶ Optional Multidrop Mode with Address Generation and Detection  RS485 with Driver Control Signal  ISO7816, T = 0 or T = 1 Protocols for Interfacing with Smart Cards  IrDA Modulation and Demodulation ̶ ̶ NACK Handling, Error Counter with Repetition and Iteration Limit  Communication at up to 115.2 Kbps SPI Mode ̶ Master or Slave ̶ Serial Clock Programmable Phase and Polarity ̶ SPI Serial Clock (SCK) Frequency up to Internal Clock Frequency MCK/6  Test Modes  Supports Connection of: ̶ ̶ Remote Loopback, Local Loopback, Automatic Echo  686 Two Peripheral DMA Controller Channels (PDC) Offers Buffer Transfer without Processor Intervention SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.3 Block Diagram Figure 34-1. USART Block Diagram (Peripheral) DMA Controller Channel Channel PIO Controller USART RXD Receiver RTS Interrupt Controller USART Interrupt TXD Transmitter CTS DTR PMC Modem Signals Control MCK DIV DSR DCD MCK/DIV RI SLCK SCK Baud Rate Generator User Interface APB Table 34-1. SPI Operating Mode PIN USART SPI Slave SPI Master RXD RXD MOSI MISO TXD TXD MISO MOSI RTS RTS – CS CTS CTS CS – SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 687 34.4 Application Block Diagram Figure 34-2. Application Block Diagram IrLAP PPP Modem Driver Serial Driver Field Bus Driver EMV Driver SPI Driver IrDA Driver USART RS232 Drivers RS232 Drivers RS485 Drivers Serial Port Differential Bus Smart Card Slot IrDA Transceivers SPI Transceiver Modem PSTN 34.5 I/O Lines Description Table 34-2. I/O Line Description Name Description Type SCK Serial Clock I/O Active Level Transmit Serial Data TXD or Master Out Slave In (MOSI) in SPI Master Mode I/O or Master In Slave Out (MISO) in SPI Slave Mode Receive Serial Data RXD or Master In Slave Out (MISO) in SPI Master Mode Input or Master Out Slave In (MOSI) in SPI Slave Mode RI Ring Indicator Input Low DSR Data Set Ready Input Low DCD Data Carrier Detect Input Low DTR Data Terminal Ready Output Low Input Low Output Low CTS RTS 688 Clear to Send or Slave Select (NSS) in SPI Slave Mode Request to Send or Slave Select (NSS) in SPI Master Mode SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.6 Product Dependencies 34.6.1 I/O Lines The pins used for interfacing the USART may be multiplexed with the PIO lines. The programmer must first program the PIO controller to assign the desired USART pins to their peripheral function. If I/O lines of the USART are not used by the application, they can be used for other purposes by the PIO Controller. To prevent the TXD line from falling when the USART is disabled, the use of an internal pull up is mandatory. If the hardware handshaking feature or Modem mode is used, the internal pull up on TXD must also be enabled. All the pins of the modems may or may not be implemented on the USART. On USARTs not equipped with the corresponding pin, the associated control bits and statuses have no effect on the behavior of the USART. Table 34-3. I/O Lines Instance Signal I/O Line Peripheral USART0 CTS0 PB8 A USART0 DCD0 PB11 B USART0 DSR0 PB10 B USART0 DTR0 PB9 B USART0 RI0 PB12 B USART0 RTS0 PB7 A USART0 RXD0 PA19 A USART0 SCK0 PA17 A USART0 TXD0 PA18 A USART1 CTS1 PA23 B USART1 RTS1 PA22 B USART1 RXD1 PA21 A USART1 SCK1 PA24 B USART1 TXD1 PA20 A USART2 CTS2 PB22 B USART2 RTS2 PB21 B USART2 RXD2 PA23 A USART2 SCK2 PA25 B USART2 TXD2 PA22 A USART3 CTS3 PC10 B USART3 RTS3 PC11 B USART3 RXD3 PC13 B USART3 SCK3 PC19 A USART3 TXD3 PC12 B SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 689 34.6.2 Power Management The USART is not continuously clocked. The programmer must first enable the USART Clock in the Power Management Controller (PMC) before using the USART. However, if the application does not require USART operations, the USART clock can be stopped when not needed and be restarted later. In this case, the USART will resume its operations where it left off. Configuring the USART does not require the USART clock to be enabled. 34.6.3 Interrupt The USART interrupt line is connected on one of the internal sources of the Interrupt Controller. Using the USART interrupt requires the Interrupt Controller to be programmed first. Note that it is not recommended to use the USART interrupt line in edge sensitive mode. 690 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.7 Functional Description The USART is capable of managing several types of serial synchronous or asynchronous communications. It supports the following communication modes:   5- to 9-bit full-duplex asynchronous serial communication ̶ MSB- or LSB-first ̶ 1, 1.5 or 2 stop bits ̶ Parity even, odd, marked, space or none ̶ By 8 or by 16 over-sampling receiver frequency ̶ Optional hardware handshaking ̶ Optional modem signals management ̶ Optional break management ̶ Optional multidrop serial communication High-speed 5- to 9-bit full-duplex synchronous serial communication ̶ MSB- or LSB-first ̶ 1 or 2 stop bits ̶ Parity even, odd, marked, space or none ̶ By 8 or by 16 over-sampling frequency ̶ Optional hardware handshaking ̶ Optional modem signals management ̶ Optional break management ̶ Optional multidrop serial communication  RS485 with driver control signal  ISO7816, T0 or T1 protocols for interfacing with smart cards ̶ NACK handling, error counter with repetition and iteration limit, inverted data.  InfraRed IrDA Modulation and Demodulation  SPI Mode  ̶ Master or Slave ̶ Serial Clock Programmable Phase and Polarity ̶ SPI Serial Clock (SCK) Frequency up to Internal Clock Frequency MCK/6 Test modes ̶ Remote loopback, local loopback, automatic echo SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 691 34.7.1 Baud Rate Generator The Baud Rate Generator provides the bit period clock named the Baud Rate Clock to both the receiver and the transmitter. The Baud Rate Generator clock source can be selected by setting the USCLKS field in the Mode Register (US_MR) between:  the Master Clock MCK  a division of the Master Clock, the divider being product dependent, but generally set to 8  the external clock, available on the SCK pin The Baud Rate Generator is based upon a 16-bit divider, which is programmed with the CD field of the Baud Rate Generator Register (US_BRGR). If CD is programmed to 0, the Baud Rate Generator does not generate any clock. If CD is programmed to 1, the divider is bypassed and becomes inactive. If the external SCK clock is selected, the duration of the low and high levels of the signal provided on the SCK pin must be longer than a Master Clock (MCK) period. The frequency of the signal provided on SCK must be at least 3 times lower than MCK in USART mode, or 6 in SPI mode. Figure 34-3. Baud Rate Generator USCLKS MCK MCK/DIV SCK Reserved CD CD SCK 0 1 2 16-bit Counter FIDI >1 3 1 0 0 0 SYNC OVER Sampling Divider 0 Baud Rate Clock 1 1 SYNC USCLKS = 3 Sampling Clock 34.7.1.1 Baud Rate in Asynchronous Mode If the USART is programmed to operate in asynchronous mode, the selected clock is first divided by CD, which is field programmed in the Baud Rate Generator Register (US_BRGR). The resulting clock is provided to the receiver as a sampling clock and then divided by 16 or 8, depending on the programming of the OVER bit in US_MR. If OVER is set to 1, the receiver sampling is 8 times higher than the baud rate clock. If OVER is cleared, the sampling is performed at 16 times the baud rate clock. The following formula performs the calculation of the Baud Rate. SelectedClock Baudrate = -------------------------------------------( 8 ( 2 – Over )CD ) This gives a maximum baud rate of MCK divided by 8, assuming that MCK is the highest possible clock and that OVER is programmed to 1. 692 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Baud Rate Calculation Example Table 34-4 shows calculations of CD to obtain a baud rate at 38400 bauds for different source clock frequencies. This table also shows the actual resulting baud rate and the error. Table 34-4. Baud Rate Example (OVER = 0) Source Clock Expected Baud Rate MHz Bit/s 3 686 400 38 400 6.00 6 38 400.00 0.00% 4 915 200 38 400 8.00 8 38 400.00 0.00% 5 000 000 38 400 8.14 8 39 062.50 1.70% 7 372 800 38 400 12.00 12 38 400.00 0.00% 8 000 000 38 400 13.02 13 38 461.54 0.16% 12 000 000 38 400 19.53 20 37 500.00 2.40% 12 288 000 38 400 20.00 20 38 400.00 0.00% 14 318 180 38 400 23.30 23 38 908.10 1.31% 14 745 600 38 400 24.00 24 38 400.00 0.00% 18 432 000 38 400 30.00 30 38 400.00 0.00% 24 000 000 38 400 39.06 39 38 461.54 0.16% 24 576 000 38 400 40.00 40 38 400.00 0.00% 25 000 000 38 400 40.69 40 38 109.76 0.76% 32 000 000 38 400 52.08 52 38 461.54 0.16% 32 768 000 38 400 53.33 53 38 641.51 0.63% 33 000 000 38 400 53.71 54 38 194.44 0.54% 40 000 000 38 400 65.10 65 38 461.54 0.16% 50 000 000 38 400 81.38 81 38 580.25 0.47% Calculation Result CD Actual Baud Rate Error Bit/s The baud rate is calculated with the following formula: BaudRate = MCK ⁄ CD × 16 The baud rate error is calculated with the following formula. It is not recommended to work with an error higher than 5%. ExpectedBaudRate Error = 1 –  ---------------------------------------------------  ActualBaudRate  SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 693 34.7.1.2 Fractional Baud Rate in Asynchronous Mode The Baud Rate generator previously defined is subject to the following limitation: the output frequency changes by only integer multiples of the reference frequency. An approach to this problem is to integrate a fractional N clock generator that has a high resolution. The generator architecture is modified to obtain Baud Rate changes by a fraction of the reference source clock. This fractional part is programmed with the FP field in the Baud Rate Generator Register (US_BRGR). If FP is not 0, the fractional part is activated. The resolution is one eighth of the clock divider. This feature is only available when using USART normal mode. The fractional Baud Rate is calculated using the following formula: SelectedClock Baudrate = --------------------------------------------------------------- 8 ( 2 – Over )  CD + FP -------    8  The modified architecture is presented below: Figure 34-4. Fractional Baud Rate Generator FP USCLKS CD Modulus Control FP MCK MCK/DIV SCK Reserved CD SCK 0 1 2 16-bit Counter 3 glitch-free logic 1 0 FIDI >1 0 0 SYNC OVER Sampling Divider 0 Baud Rate Clock 1 1 SYNC USCLKS = 3 Sampling Clock 34.7.1.3 Baud Rate in Synchronous Mode or SPI Mode If the USART is programmed to operate in synchronous mode, the selected clock is simply divided by the field CD in US_BRGR. SelectedClock BaudRate = -------------------------------------CD In synchronous mode, if the external clock is selected (USCLKS = 3), the clock is provided directly by the signal on the USART SCK pin. No division is active. The value written in US_BRGR has no effect. The external clock frequency must be at least 3 times lower than the system clock. In synchronous mode master (USCLKS = 0 or 1, CLK0 set to 1), the receive part limits the SCK maximum frequency to MCK/3 in USART mode, or MCK/6 in SPI mode. When either the external clock SCK or the internal clock divided (MCK/DIV) is selected, the value programmed in CD must be even if the user has to ensure a 50:50 mark/space ratio on the SCK pin. If the internal clock MCK is selected, the Baud Rate Generator ensures a 50:50 duty cycle on the SCK pin, even if the value programmed in CD is odd. 694 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.7.1.4 Baud Rate in ISO 7816 Mode The ISO7816 specification defines the bit rate with the following formula: Di B = ------ × f Fi where:  B is the bit rate  Di is the bit-rate adjustment factor  Fi is the clock frequency division factor  f is the ISO7816 clock frequency (Hz) Di is a binary value encoded on a 4-bit field, named DI, as represented in Table 34-5. Table 34-5. Binary and Decimal Values for Di DI field 0001 0010 0011 0100 0101 0110 1000 1001 1 2 4 8 16 32 12 20 Di (decimal) Fi is a binary value encoded on a 4-bit field, named FI, as represented in Table 34-6. Table 34-6. Binary and Decimal Values for Fi FI field 0000 0001 0010 0011 0100 0101 0110 1001 1010 1011 1100 1101 Fi (decimal) 372 372 558 744 1116 1488 1860 512 768 1024 1536 2048 Table 34-7 shows the resulting Fi/Di Ratio, which is the ratio between the ISO7816 clock and the baud rate clock. Table 34-7. Possible Values for the Fi/Di Ratio Fi/Di 372 558 774 1116 1488 1806 512 768 1024 1536 2048 1 372 558 744 1116 1488 1860 512 768 1024 1536 2048 2 186 279 372 558 744 930 256 384 512 768 1024 4 93 139.5 186 279 372 465 128 192 256 384 512 8 46.5 69.75 93 139.5 186 232.5 64 96 128 192 256 16 23.25 34.87 46.5 69.75 93 116.2 32 48 64 96 128 32 11.62 17.43 23.25 34.87 46.5 58.13 16 24 32 48 64 12 31 46.5 62 93 124 155 42.66 64 85.33 128 170.6 20 18.6 27.9 37.2 55.8 74.4 93 25.6 38.4 51.2 76.8 102.4 If the USART is configured in ISO7816 Mode, the clock selected by the USCLKS field in the Mode Register (US_MR) is first divided by the value programmed in the field CD in the Baud Rate Generator Register (US_BRGR). The resulting clock can be provided to the SCK pin to feed the smart card clock inputs. This means that the CLKO bit can be set in US_MR. This clock is then divided by the value programmed in the FI_DI_RATIO field in the FI_DI_Ratio register (US_FIDI). This is performed by the Sampling Divider, which performs a division by up to 2047 in ISO7816 Mode. The non-integer values of the Fi/Di Ratio are not supported and the user must program the FI_DI_RATIO field to a value as close as possible to the expected value. The FI_DI_RATIO field resets to the value 0x174 (372 in decimal) and is the most common divider between the ISO7816 clock and the bit rate (Fi = 372, Di = 1). Figure 34-5 shows the relation between the Elementary Time Unit, corresponding to a bit time, and the ISO 7816 clock. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 695 Figure 34-5. Elementary Time Unit (ETU) FI_DI_RATIO ISO7816 Clock Cycles ISO7816 Clock on SCK ISO7816 I/O Line on TXD 1 ETU 34.7.2 Receiver and Transmitter Control After reset, the receiver is disabled. The user must enable the receiver by setting the RXEN bit in the Control Register (US_CR). However, the receiver registers can be programmed before the receiver clock is enabled. After reset, the transmitter is disabled. The user must enable it by setting the TXEN bit in the Control Register (US_CR). However, the transmitter registers can be programmed before being enabled. The Receiver and the Transmitter can be enabled together or independently. At any time, the software can perform a reset on the receiver or the transmitter of the USART by setting the corresponding bit, RSTRX and RSTTX respectively, in the Control Register (US_CR). The software resets clear the status flag and reset internal state machines but the user interface configuration registers hold the value configured prior to software reset. Regardless of what the receiver or the transmitter is performing, the communication is immediately stopped. The user can also independently disable the receiver or the transmitter by setting RXDIS and TXDIS respectively in US_CR. If the receiver is disabled during a character reception, the USART waits until the end of reception of the current character, then the reception is stopped. If the transmitter is disabled while it is operating, the USART waits the end of transmission of both the current character and character being stored in the Transmit Holding Register (US_THR). If a timeguard is programmed, it is handled normally. 34.7.3 Synchronous and Asynchronous Modes 34.7.3.1 Transmitter Operations The transmitter performs the same in both synchronous and asynchronous operating modes (SYNC = 0 or SYNC = 1). One start bit, up to 9 data bits, one optional parity bit and up to two stop bits are successively shifted out on the TXD pin at each falling edge of the programmed serial clock. The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register (US_MR). Nine bits are selected by setting the MODE 9 bit regardless of the CHRL field. The parity bit is set according to the PAR field in US_MR. The even, odd, space, marked or none parity bit can be configured. The MSBF field in US_MR configures which data bit is sent first. If written to 1, the most significant bit is sent first. If written to 0, the less significant bit is sent first. The number of stop bits is selected by the NBSTOP field in US_MR. The 1.5 stop bit is supported in asynchronous mode only. 696 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 34-6. Character Transmit Example: 8-bit, Parity Enabled One Stop Baud Rate Clock TXD D0 Start Bit D1 D2 D3 D4 D5 D6 D7 Parity Bit Stop Bit The characters are sent by writing in the Transmit Holding Register (US_THR). The transmitter reports two status bits in the Channel Status Register (US_CSR): TXRDY (Transmitter Ready), which indicates that US_THR is empty and TXEMPTY, which indicates that all the characters written in US_THR have been processed. When the current character processing is completed, the last character written in US_THR is transferred into the Shift Register of the transmitter and US_THR becomes empty, thus TXRDY rises. Both TXRDY and TXEMPTY bits are low when the transmitter is disabled. Writing a character in US_THR while TXRDY is low has no effect and the written character is lost. Figure 34-7. Transmitter Status Baud Rate Clock TXD Start D0 Bit D1 D2 D3 D4 D5 D6 D7 Parity Stop Start D0 Bit Bit Bit D1 D2 D3 D4 D5 D6 D7 Parity Stop Bit Bit Write US_THR TXRDY TXEMPTY 34.7.3.2 Manchester Encoder When the Manchester encoder is in use, characters transmitted through the USART are encoded based on biphase Manchester II format. To enable this mode, set the MAN field in the US_MR register to 1. Depending on polarity configuration, a logic level (zero or one), is transmitted as a coded signal one-to-zero or zero-to-one. Thus, a transition always occurs at the midpoint of each bit time. It consumes more bandwidth than the original NRZ signal (2x) but the receiver has more error control since the expected input must show a change at the center of a bit cell. An example of Manchester encoded sequence is: the byte 0xB1 or 10110001 encodes to 10 01 10 10 01 01 01 10, assuming the default polarity of the encoder. Figure 34-8 illustrates this coding scheme. Figure 34-8. NRZ to Manchester Encoding NRZ encoded data Manchester encoded data 1 0 1 1 0 0 0 1 Txd SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 697 The Manchester encoded character can also be encapsulated by adding both a configurable preamble and a start frame delimiter pattern. Depending on the configuration, the preamble is a training sequence, composed of a predefined pattern with a programmable length from 1 to 15 bit times. If the preamble length is set to 0, the preamble waveform is not generated prior to any character. The preamble pattern is chosen among the following sequences: ALL_ONE, ALL_ZERO, ONE_ZERO or ZERO_ONE, writing the field TX_PP in the US_MAN register, the field TX_PL is used to configure the preamble length. Figure 34-9 illustrates and defines the valid patterns. To improve flexibility, the encoding scheme can be configured using the TX_MPOL field in the US_MAN register. If the TX_MPOL field is set to zero (default), a logic zero is encoded with a zero-to-one transition and a logic one is encoded with a one-to-zero transition. If the TX_MPOL field is set to one, a logic one is encoded with a one-to-zero transition and a logic zero is encoded with a zero-to-one transition. Figure 34-9. Preamble Patterns, Default Polarity Assumed Manchester encoded data Txd SFD DATA SFD DATA SFD DATA SFD DATA 8 bit width "ALL_ONE" Preamble Manchester encoded data Txd 8 bit width "ALL_ZERO" Preamble Manchester encoded data Txd 8 bit width "ZERO_ONE" Preamble Manchester encoded data Txd 8 bit width "ONE_ZERO" Preamble A start frame delimiter is to be configured using the ONEBIT field in the US_MR register. It consists of a userdefined pattern that indicates the beginning of a valid data. Figure 34-10 illustrates these patterns. If the start frame delimiter, also known as start bit, is one bit, (ONEBIT to 1), a logic zero is Manchester encoded and indicates that a new character is being sent serially on the line. If the start frame delimiter is a synchronization pattern also referred to as sync (ONEBIT to 0), a sequence of 3 bit times is sent serially on the line to indicate the start of a new character. The sync waveform is in itself an invalid Manchester waveform as the transition occurs at the middle of the second bit time. Two distinct sync patterns are used: the command sync and the data sync. The command sync has a logic one level for one and a half bit times, then a transition to logic zero for the second one and a half bit times. If the MODSYNC field in the US_MR register is set to 1, the next character is a command. If it is set to 0, the next character is a data. When direct memory access is used, the MODSYNC field can be immediately updated with a modified character located in memory. To enable this mode, VAR_SYNC field in US_MR register must be set to 1. In this case, the MODSYNC field in US_MR is bypassed and the sync configuration is held in the TXSYNH in the US_THR register. The USART character format is modified and includes sync information. 698 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 34-10. Start Frame Delimiter Preamble Length is set to 0 SFD Manchester encoded data DATA Txd One bit start frame delimiter SFD Manchester encoded data DATA Txd SFD Manchester encoded data Command Sync start frame delimiter DATA Txd Data Sync start frame delimiter Drift Compensation Drift compensation is available only in 16X oversampling mode. An hardware recovery system allows a larger clock drift. To enable the hardware system, the bit in the USART_MAN register must be set. If the RXD edge is one 16X clock cycle from the expected edge, this is considered as normal jitter and no corrective actions is taken. If the RXD event is between 4 and 2 clock cycles before the expected edge, then the current period is shortened by one clock cycle. If the RXD event is between 2 and 3 clock cycles after the expected edge, then the current period is lengthened by one clock cycle. These intervals are considered to be drift and so corrective actions are automatically taken. Figure 34-11. Bit Resynchronization Oversampling 16x Clock RXD Sampling point Expected edge Synchro. Error Synchro. Jump Tolerance Sync Jump Synchro. Error 34.7.3.3 Asynchronous Receiver If the USART is programmed in asynchronous operating mode (SYNC = 0), the receiver oversamples the RXD input line. The oversampling is either 16 or 8 times the Baud Rate clock, depending on the OVER bit in the Mode Register (US_MR). The receiver samples the RXD line. If the line is sampled during one half of a bit time to 0, a start bit is detected and data, parity and stop bits are successively sampled on the bit rate clock. If the oversampling is 16, (OVER to 0), a start is detected at the eighth sample to 0. Then, data bits, parity bit and stop bit are sampled on each 16 sampling clock cycle. If the oversampling is 8 (OVER to 1), a start bit is detected at the fourth sample to 0. Then, data bits, parity bit and stop bit are sampled on each 8 sampling clock cycle. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 699 The number of data bits, first bit sent and parity mode are selected by the same fields and bits as the transmitter, i.e. respectively CHRL, MODE9, MSBF and PAR. For the synchronization mechanism only, the number of stop bits has no effect on the receiver as it considers only one stop bit, regardless of the field NBSTOP, so that resynchronization between the receiver and the transmitter can occur. Moreover, as soon as the stop bit is sampled, the receiver starts looking for a new start bit so that resynchronization can also be accomplished when the transmitter is operating with one stop bit. Figure 34-12 and Figure 34-13 illustrate start detection and character reception when USART operates in asynchronous mode. Figure 34-12. Asynchronous Start Detection Baud Rate Clock Sampling Clock (x16) RXD Sampling 1 2 3 4 5 6 7 8 1 2 3 4 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 D0 Sampling Start Detection RXD Sampling 1 2 3 4 5 6 7 0 1 Start Rejection Figure 34-13. Asynchronous Character Reception Example: 8-bit, Parity Enabled Baud Rate Clock RXD Start Detection 16 16 16 16 16 16 16 16 16 16 samples samples samples samples samples samples samples samples samples samples D0 D1 D2 D3 D4 D5 D6 D7 Parity Bit Stop Bit 34.7.3.4 Manchester Decoder When the MAN field in US_MR register is set to 1, the Manchester decoder is enabled. The decoder performs both preamble and start frame delimiter detection. One input line is dedicated to Manchester encoded input data. An optional preamble sequence can be defined, its length is user-defined and totally independent of the emitter side. Use RX_PL in US_MAN register to configure the length of the preamble sequence. If the length is set to 0, no preamble is detected and the function is disabled. In addition, the polarity of the input stream is programmable with RX_MPOL field in US_MAN register. Depending on the desired application the preamble pattern matching is to be defined via the RX_PP field in US_MAN. See Figure 34-9 for available preamble patterns. 700 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Unlike preamble, the start frame delimiter is shared between Manchester Encoder and Decoder. So, if ONEBIT field is set to 1, only a zero encoded Manchester can be detected as a valid start frame delimiter. If ONEBIT is set to 0, only a sync pattern is detected as a valid start frame delimiter. Decoder operates by detecting transition on incoming stream. If RXD is sampled during one quarter of a bit time to zero, a start bit is detected. See Figure 3414. The sample pulse rejection mechanism applies. Figure 34-14. Asynchronous Start Bit Detection Sampling Clock (16 x) Manchester encoded data Txd Start Detection 1 2 3 4 The receiver is activated and starts Preamble and Frame Delimiter detection, sampling the data at one quarter and then three quarters. If a valid preamble pattern or start frame delimiter is detected, the receiver continues decoding with the same synchronization. If the stream does not match a valid pattern or a valid start frame delimiter, the receiver re-synchronizes on the next valid edge.The minimum time threshold to estimate the bit value is three quarters of a bit time. If a valid preamble (if used) followed with a valid start frame delimiter is detected, the incoming stream is decoded into NRZ data and passed to USART for processing. Figure 34-15 illustrates Manchester pattern mismatch. When incoming data stream is passed to the USART, the receiver is also able to detect Manchester code violation. A code violation is a lack of transition in the middle of a bit cell. In this case, MANE flag in US_CSR register is raised. It is cleared by writing the Control Register (US_CR) with the RSTSTA bit to 1. See Figure 34-16 for an example of Manchester error detection during data phase. Figure 34-15. Preamble Pattern Mismatch Preamble Mismatch Manchester coding error Manchester encoded data Preamble Mismatch invalid pattern SFD Txd DATA Preamble Length is set to 8 Figure 34-16. Manchester Error Flag Preamble Length is set to 4 Elementary character bit time SFD Manchester encoded data Txd Entering USART character area sampling points Preamble subpacket and Start Frame Delimiter were successfully decoded Manchester Coding Error detected SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 701 When the start frame delimiter is a sync pattern (ONEBIT field to 0), both command and data delimiter are supported. If a valid sync is detected, the received character is written as RXCHR field in the US_RHR register and the RXSYNH is updated. RXCHR is set to 1 when the received character is a command, and it is set to 0 if the received character is a data. This mechanism alleviates and simplifies the direct memory access as the character contains its own sync field in the same register. As the decoder is setup to be used in unipolar mode, the first bit of the frame has to be a zero-to-one transition. 34.7.3.5 Radio Interface: Manchester Encoded USART Application This section describes low data rate RF transmission systems and their integration with a Manchester encoded USART. These systems are based on transmitter and receiver ICs that support ASK and FSK modulation schemes. The goal is to perform full duplex radio transmission of characters using two different frequency carriers. See the configuration in Figure 34-17. Figure 34-17. Manchester Encoded Characters RF Transmission Fup frequency Carrier ASK/FSK Upstream Receiver Upstream Emitter LNA VCO RF filter Demod Serial Configuration Interface control Fdown frequency Carrier bi-dir line Manchester decoder USART Receiver Manchester encoder USART Emitter ASK/FSK downstream transmitter Downstream Receiver PA RF filter Mod VCO control The USART module is configured as a Manchester encoder/decoder. Looking at the downstream communication channel, Manchester encoded characters are serially sent to the RF emitter. This may also include a user defined preamble and a start frame delimiter. Mostly, preamble is used in the RF receiver to distinguish between a valid data from a transmitter and signals due to noise. The Manchester stream is then modulated. See Figure 34-18 for an example of ASK modulation scheme. When a logic one is sent to the ASK modulator, the power amplifier, referred to as PA, is enabled and transmits an RF signal at downstream frequency. When a logic zero is transmitted, the RF signal is turned off. If the FSK modulator is activated, two different frequencies are used to transmit data. When a logic 1 is sent, the modulator outputs an RF signal at frequency F0 and switches to F1 if the data sent is a 0. See Figure 34-19. From the receiver side, another carrier frequency is used. The RF receiver performs a bit check operation examining demodulated data stream. If a valid pattern is detected, the receiver switches to receiving mode. The demodulated stream is sent to the Manchester decoder. Because of bit checking inside RF IC, the data transferred to the microcontroller is reduced by a user-defined number of bits. The Manchester preamble length is to be defined in accordance with the RF IC configuration. 702 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 34-18. ASK Modulator Output 1 0 0 1 0 0 1 NRZ stream Manchester encoded data default polarity unipolar output Txd ASK Modulator Output Uptstream Frequency F0 Figure 34-19. FSK Modulator Output 1 NRZ stream Manchester encoded data default polarity unipolar output Txd FSK Modulator Output Uptstream Frequencies [F0, F0+offset] 34.7.3.6 Synchronous Receiver In synchronous mode (SYNC = 1), the receiver samples the RXD signal on each rising edge of the Baud Rate Clock. If a low level is detected, it is considered as a start. All data bits, the parity bit and the stop bits are sampled and the receiver waits for the next start bit. Synchronous mode operations provide a high speed transfer capability. Configuration fields and bits are the same as in asynchronous mode. Figure 34-20 illustrates a character reception in synchronous mode. Figure 34-20. Synchronous Mode Character Reception Example: 8-bit, Parity Enabled 1 Stop Baud Rate Clock RXD Sampling Start D0 D1 D2 D3 D4 D5 D6 D7 Stop Bit Parity Bit 34.7.3.7 Receiver Operations When a character reception is completed, it is transferred to the Receive Holding Register (US_RHR) and the RXRDY bit in the Status Register (US_CSR) rises. If a character is completed while the RXRDY is set, the OVRE (Overrun Error) bit is set. The last character is transferred into US_RHR and overwrites the previous one. The OVRE bit is cleared by writing the Control Register (US_CR) with the RSTSTA (Reset Status) bit to 1. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 703 Figure 34-21. Receiver Status Baud Rate Clock RXD Start D0 Bit D1 D2 D3 D4 D5 D6 D7 Parity Stop Start D0 Bit Bit Bit D1 D2 D3 D4 D5 D6 D7 Parity Stop Bit Bit RSTSTA = 1 Write US_CR Read US_RHR RXRDY OVRE 34.7.3.8 Parity The USART supports five parity modes selected by programming the PAR field in the Mode Register (US_MR). The PAR field also enables the Multidrop mode, see “Multidrop Mode” on page 705. Even and odd parity bit generation and error detection are supported. If even parity is selected, the parity generator of the transmitter drives the parity bit to 0 if a number of 1s in the character data bit is even, and to 1 if the number of 1s is odd. Accordingly, the receiver parity checker counts the number of received 1s and reports a parity error if the sampled parity bit does not correspond. If odd parity is selected, the parity generator of the transmitter drives the parity bit to 1 if a number of 1s in the character data bit is even, and to 0 if the number of 1s is odd. Accordingly, the receiver parity checker counts the number of received 1s and reports a parity error if the sampled parity bit does not correspond. If the mark parity is used, the parity generator of the transmitter drives the parity bit to 1 for all characters. The receiver parity checker reports an error if the parity bit is sampled to 0. If the space parity is used, the parity generator of the transmitter drives the parity bit to 0 for all characters. The receiver parity checker reports an error if the parity bit is sampled to 1. If parity is disabled, the transmitter does not generate any parity bit and the receiver does not report any parity error. Table 34-8 shows an example of the parity bit for the character 0x41 (character ASCII “A”) depending on the configuration of the USART. Because there are two bits to 1, 1 bit is added when a parity is odd, or 0 is added when a parity is even. Table 34-8. Parity Bit Examples Character Hexa Binary Parity Bit Parity Mode A 0x41 0100 0001 1 Odd A 0x41 0100 0001 0 Even A 0x41 0100 0001 1 Mark A 0x41 0100 0001 0 Space A 0x41 0100 0001 None None When the receiver detects a parity error, it sets the PARE (Parity Error) bit in the Channel Status Register (US_CSR). The PARE bit can be cleared by writing the Control Register (US_CR) with the RSTSTA bit to 1. Figure 34-22 illustrates the parity bit status setting and clearing. 704 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 34-22. Parity Error Baud Rate Clock RXD Start D0 Bit D1 D2 D3 D4 D5 D6 D7 Bad Stop Parity Bit Bit RSTSTA = 1 Write US_CR PARE RXRDY 34.7.3.9 Multidrop Mode If the PAR field in the Mode Register (US_MR) is programmed to the value 0x6 or 0x07, the USART runs in Multidrop Mode. This mode differentiates the data characters and the address characters. Data is transmitted with the parity bit to 0 and addresses are transmitted with the parity bit to 1. If the USART is configured in multidrop mode, the receiver sets the PARE parity error bit when the parity bit is high and the transmitter is able to send a character with the parity bit high when the Control Register is written with the SENDA bit to 1. To handle parity error, the PARE bit is cleared when the Control Register is written with the bit RSTSTA to 1. The transmitter sends an address byte (parity bit set) when SENDA is written to US_CR. In this case, the next byte written to US_THR is transmitted as an address. Any character written in US_THR without having written the command SENDA is transmitted normally with the parity to 0. 34.7.3.10Transmitter Timeguard The timeguard feature enables the USART interface with slow remote devices. The timeguard function enables the transmitter to insert an idle state on the TXD line between two characters. This idle state actually acts as a long stop bit. The duration of the idle state is programmed in the TG field of the Transmitter Timeguard Register (US_TTGR). When this field is programmed to zero no timeguard is generated. Otherwise, the transmitter holds a high level on TXD after each transmitted byte during the number of bit periods programmed in TG in addition to the number of stop bits. As illustrated in Figure 34-23, the behavior of TXRDY and TXEMPTY status bits is modified by the programming of a timeguard. TXRDY rises only when the start bit of the next character is sent, and thus remains to 0 during the timeguard transmission if a character has been written in US_THR. TXEMPTY remains low until the timeguard transmission is completed as the timeguard is part of the current character being transmitted. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 705 Figure 34-23. Timeguard Operations TG = 4 TG = 4 Baud Rate Clock TXD Start D0 Bit D1 D2 D3 D4 D5 D6 D7 Parity Stop Bit Bit Start D0 Bit D1 D2 D3 D4 D5 D6 D7 Parity Stop Bit Bit Write US_THR TXRDY TXEMPTY Table 34-9 indicates the maximum length of a timeguard period that the transmitter can handle in relation to the function of the Baud Rate. Table 34-9. 706 Maximum Timeguard Length Depending on Baud Rate Baud Rate Bit time Timeguard Bit/sec µs ms 1 200 833 212.50 9 600 104 26.56 14400 69.4 17.71 19200 52.1 13.28 28800 34.7 8.85 33400 29.9 7.63 56000 17.9 4.55 57600 17.4 4.43 115200 8.7 2.21 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.7.3.11Receiver Time-out The Receiver Time-out provides support in handling variable-length frames. This feature detects an idle condition on the RXD line. When a time-out is detected, the bit TIMEOUT in the Channel Status Register (US_CSR) rises and can generate an interrupt, thus indicating to the driver an end of frame. The time-out delay period (during which the receiver waits for a new character) is programmed in the TO field of the Receiver Time-out Register (US_RTOR). If the TO field is programmed to 0, the Receiver Time-out is disabled and no time-out is detected. The TIMEOUT bit in US_CSR remains to 0. Otherwise, the receiver loads a 16-bit counter with the value programmed in TO. This counter is decremented at each bit period and reloaded each time a new character is received. If the counter reaches 0, the TIMEOUT bit in the Status Register rises. Then, the user can either:  Stop the counter clock until a new character is received. This is performed by writing the Control Register (US_CR) with the STTTO (Start Time-out) bit to 1. In this case, the idle state on RXD before a new character is received will not provide a time-out. This prevents having to handle an interrupt before a character is received and allows waiting for the next idle state on RXD after a frame is received.  Obtain an interrupt while no character is received. This is performed by writing US_CR with the RETTO (Reload and Start Time-out) bit to 1. If RETTO is performed, the counter starts counting down immediately from the value TO. This enables generation of a periodic interrupt so that a user time-out can be handled, for example when no key is pressed on a keyboard. If STTTO is performed, the counter clock is stopped until a first character is received. The idle state on RXD before the start of the frame does not provide a time-out. This prevents having to obtain a periodic interrupt and enables a wait of the end of frame when the idle state on RXD is detected. If RETTO is performed, the counter starts counting down immediately from the value TO. This enables generation of a periodic interrupt so that a user time-out can be handled, for example when no key is pressed on a keyboard. Figure 34-24 shows the block diagram of the Receiver Time-out feature. Figure 34-24. Receiver Time-out Block Diagram TO Baud Rate Clock 1 D Q Clock 16-bit Time-out Counter 16-bit Value = STTTO Character Received Clear Load TIMEOUT 0 RETTO SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 707 Table 34-10 gives the maximum time-out period for some standard baud rates. Table 34-10. Maximum Time-out Period Baud Rate Bit Time Time-out bit/sec µs ms 600 1 667 109 225 1 200 833 54 613 2 400 417 27 306 4 800 208 13 653 9 600 104 6 827 14400 69 4 551 19200 52 3 413 28800 35 2 276 33400 30 1 962 56000 18 1 170 57600 17 1 138 200000 5 328 34.7.3.12Framing Error The receiver is capable of detecting framing errors. A framing error happens when the stop bit of a received character is detected at level 0. This can occur if the receiver and the transmitter are fully desynchronized. A framing error is reported on the FRAME bit of the Channel Status Register (US_CSR). The FRAME bit is asserted in the middle of the stop bit as soon as the framing error is detected. It is cleared by writing the Control Register (US_CR) with the RSTSTA bit to 1. Figure 34-25. Framing Error Status Baud Rate Clock RXD Start D0 Bit Write US_CR FRAME RXRDY 708 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 D1 D2 D3 D4 D5 D6 D7 Parity Stop Bit Bit RSTSTA = 1 34.7.3.13Transmit Break The user can request the transmitter to generate a break condition on the TXD line. A break condition drives the TXD line low during at least one complete character. It appears the same as a 0x00 character sent with the parity and the stop bits to 0. However, the transmitter holds the TXD line at least during one character until the user requests the break condition to be removed. A break is transmitted by writing the Control Register (US_CR) with the STTBRK bit to 1. This can be performed at any time, either while the transmitter is empty (no character in either the Shift Register or in US_THR) or when a character is being transmitted. If a break is requested while a character is being shifted out, the character is first completed before the TXD line is held low. Once STTBRK command is requested further STTBRK commands are ignored until the end of the break is completed. The break condition is removed by writing US_CR with the STPBRK bit to 1. If the STPBRK is requested before the end of the minimum break duration (one character, including start, data, parity and stop bits), the transmitter ensures that the break condition completes. The transmitter considers the break as though it is a character, i.e. the STTBRK and STPBRK commands are taken into account only if the TXRDY bit in US_CSR is to 1 and the start of the break condition clears the TXRDY and TXEMPTY bits as if a character is processed. Writing US_CR with both STTBRK and STPBRK bits to 1 can lead to an unpredictable result. All STPBRK commands requested without a previous STTBRK command are ignored. A byte written into the Transmit Holding Register while a break is pending, but not started, is ignored. After the break condition, the transmitter returns the TXD line to 1 for a minimum of 12 bit times. Thus, the transmitter ensures that the remote receiver detects correctly the end of break and the start of the next character. If the timeguard is programmed with a value higher than 12, the TXD line is held high for the timeguard period. After holding the TXD line for this period, the transmitter resumes normal operations. Figure 34-26 illustrates the effect of both the Start Break (STTBRK) and Stop Break (STPBRK) commands on the TXD line. Figure 34-26. Break Transmission Baud Rate Clock TXD Start D0 Bit D1 D2 D3 D4 D5 STTBRK = 1 D6 D7 Parity Stop Bit Bit Break Transmission End of Break STPBRK = 1 Write US_CR TXRDY TXEMPTY SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 709 34.7.3.14Receive Break The receiver detects a break condition when all data, parity and stop bits are low. This corresponds to detecting a framing error with data to 0x00, but FRAME remains low. When the low stop bit is detected, the receiver asserts the RXBRK bit in US_CSR. This bit may be cleared by writing the Control Register (US_CR) with the bit RSTSTA to 1. An end of receive break is detected by a high level for at least 2/16 of a bit period in asynchronous operating mode or one sample at high level in synchronous operating mode. The end of break detection also asserts the RXBRK bit. 34.7.3.15Hardware Handshaking The USART features a hardware handshaking out-of-band flow control. The RTS and CTS pins are used to connect with the remote device, as shown in Figure 34-27. Figure 34-27. Connection with a Remote Device for Hardware Handshaking USART Remote Device TXD RXD RXD TXD CTS RTS RTS CTS Setting the USART to operate with hardware handshaking is performed by writing the USART_MODE field in the Mode Register (US_MR) to the value 0x2. The USART behavior when hardware handshaking is enabled is the same as the behavior in standard synchronous or asynchronous mode, except that the receiver drives the RTS pin as described below and the level on the CTS pin modifies the behavior of the transmitter as described below. Using this mode requires using the PDC channel for reception. The transmitter can handle hardware handshaking in any case. Figure 34-28 shows how the receiver operates if hardware handshaking is enabled. The RTS pin is driven high if the receiver is disabled and if the status RXBUFF (Receive Buffer Full) coming from the PDC channel is high. Normally, the remote device does not start transmitting while its CTS pin (driven by RTS) is high. As soon as the Receiver is enabled, the RTS falls, indicating to the remote device that it can start transmitting. Defining a new buffer to the PDC clears the status bit RXBUFF and, as a result, asserts the pin RTS low. Figure 34-28. Receiver Behavior when Operating with Hardware Handshaking RXD RXEN = 1 RXDIS = 1 Write US_CR RTS RXBUFF Figure 34-29 shows how the transmitter operates if hardware handshaking is enabled. The CTS pin disables the transmitter. If a character is being processing, the transmitter is disabled only after the completion of the current character and transmission of the next character happens as soon as the pin CTS falls. 710 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 34-29. Transmitter Behavior when Operating with Hardware Handshaking CTS TXD 34.7.4 ISO7816 Mode The USART features an ISO7816-compatible operating mode. This mode permits interfacing with smart cards and Security Access Modules (SAM) communicating through an ISO7816 link. Both T = 0 and T = 1 protocols defined by the ISO7816 specification are supported. Setting the USART in ISO7816 mode is performed by writing the USART_MODE field in the Mode Register (US_MR) to the value 0x4 for protocol T = 0 and to the value 0x5 for protocol T = 1. 34.7.4.1 ISO7816 Mode Overview The ISO7816 is a half duplex communication on only one bidirectional line. The baud rate is determined by a division of the clock provided to the remote device (see “Baud Rate Generator” on page 692). The USART connects to a smart card as shown in Figure 34-30. The TXD line becomes bidirectional and the Baud Rate Generator feeds the ISO7816 clock on the SCK pin. As the TXD pin becomes bidirectional, its output remains driven by the output of the transmitter but only when the transmitter is active while its input is directed to the input of the receiver. The USART is considered as the master of the communication as it generates the clock. Figure 34-30. Connection of a Smart Card to the USART USART SCK TXD CLK I/O Smart Card When operating in ISO7816, either in T = 0 or T = 1 modes, the character format is fixed. The configuration is 8 data bits, even parity and 1 or 2 stop bits, regardless of the values programmed in the CHRL, MODE9, PAR and CHMODE fields. MSBF can be used to transmit LSB or MSB first. Parity Bit (PAR) can be used to transmit in normal or inverse mode. Refer to “USART Mode Register” on page 730 and “PAR: Parity Type” on page 731. The USART cannot operate concurrently in both receiver and transmitter modes as the communication is unidirectional at a time. It has to be configured according to the required mode by enabling or disabling either the receiver or the transmitter as desired. Enabling both the receiver and the transmitter at the same time in ISO7816 mode may lead to unpredictable results. The ISO7816 specification defines an inverse transmission format. Data bits of the character must be transmitted on the I/O line at their negative value. The USART does not support this format and the user has to perform an exclusive OR on the data before writing it in the Transmit Holding Register (US_THR) or after reading it in the Receive Holding Register (US_RHR). 34.7.4.2 Protocol T = 0 In T = 0 protocol, a character is made up of one start bit, eight data bits, one parity bit and one guard time, which lasts two bit times. The transmitter shifts out the bits and does not drive the I/O line during the guard time. If no parity error is detected, the I/O line remains to 1 during the guard time and the transmitter can continue with the transmission of the next character, as shown in Figure 34-31. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 711 If a parity error is detected by the receiver, it drives the I/O line to 0 during the guard time, as shown in Figure 3432. This error bit is also named NACK, for Non Acknowledge. In this case, the character lasts 1 bit time more, as the guard time length is the same and is added to the error bit time which lasts 1 bit time. When the USART is the receiver and it detects an error, it does not load the erroneous character in the Receive Holding Register (US_RHR). It appropriately sets the PARE bit in the Status Register (US_SR) so that the software can handle the error. Figure 34-31. T = 0 Protocol without Parity Error Baud Rate Clock RXD Start Bit D0 D2 D1 D4 D3 D5 D6 D7 Parity Guard Guard Next Bit Time 1 Time 2 Start Bit Figure 34-32. T = 0 Protocol with Parity Error Baud Rate Clock Error I/O Start Bit D0 D1 D2 D3 D4 D5 D6 D7 Parity Guard Bit Time 1 D0 Guard Start Time 2 Bit D1 Repetition Receive Error Counter The USART receiver also records the total number of errors. This can be read in the Number of Error (US_NER) register. The NB_ERRORS field can record up to 255 errors. Reading US_NER automatically clears the NB_ERRORS field. Receive NACK Inhibit The USART can also be configured to inhibit an error. This can be achieved by setting the INACK bit in the Mode Register (US_MR). If INACK is to 1, no error signal is driven on the I/O line even if a parity bit is detected. Moreover, if INACK is set, the erroneous received character is stored in the Receive Holding Register, as if no error occurred and the RXRDY bit does rise. Transmit Character Repetition When the USART is transmitting a character and gets a NACK, it can automatically repeat the character before moving on to the next one. Repetition is enabled by writing the MAX_ITERATION field in the Mode Register (US_MR) at a value higher than 0. Each character can be transmitted up to eight times; the first transmission plus seven repetitions. If MAX_ITERATION does not equal zero, the USART repeats the character as many times as the value loaded in MAX_ITERATION. When the USART repetition number reaches MAX_ITERATION, the ITERATION bit is set in the Channel Status Register (US_CSR). If the repetition of the character is acknowledged by the receiver, the repetitions are stopped and the iteration counter is cleared. The ITERATION bit in US_CSR can be cleared by writing the Control Register with the RSIT bit to 1. 712 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Disable Successive Receive NACK The receiver can limit the number of successive NACKs sent back to the remote transmitter. This is programmed by setting the bit DSNACK in the Mode Register (US_MR). The maximum number of NACK transmitted is programmed in the MAX_ITERATION field. As soon as MAX_ITERATION is reached, the character is considered as correct, an acknowledge is sent on the line and the ITERATION bit in the Channel Status Register is set. 34.7.4.3 Protocol T = 1 When operating in ISO7816 protocol T = 1, the transmission is similar to an asynchronous format with only one stop bit. The parity is generated when transmitting and checked when receiving. Parity error detection sets the PARE bit in the Channel Status Register (US_CSR). 34.7.5 IrDA Mode The USART features an IrDA mode supplying half-duplex point-to-point wireless communication. It embeds the modulator and demodulator which allows a glueless connection to the infrared transceivers, as shown in Figure 34-33. The modulator and demodulator are compliant with the IrDA specification version 1.1 and support data transfer speeds ranging from 2.4 Kb/s to 115.2 Kb/s. The USART IrDA mode is enabled by setting the USART_MODE field in the Mode Register (US_MR) to the value 0x8. The IrDA Filter Register (US_IF) allows configuring the demodulator filter. The USART transmitter and receiver operate in a normal asynchronous mode and all parameters are accessible. Note that the modulator and the demodulator are activated. Figure 34-33. Connection to IrDA Transceivers USART IrDA Transceivers Receiver Demodulator Transmitter Modulator RXD RX TX TXD The receiver and the transmitter must be enabled or disabled according to the direction of the transmission to be managed. To receive IrDA signals, the following needs to be done:  Disable TX and Enable RX  Configure the TXD pin as PIO and set it as an output to 0 (to avoid LED emission). Disable the internal pullup (better for power consumption).  Receive data SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 713 34.7.5.1 IrDA Modulation For baud rates up to and including 115.2 Kbits/sec, the RZI modulation scheme is used. “0” is represented by a light pulse of 3/16th of a bit time. Some examples of signal pulse duration are shown in Table 34-11. Table 34-11. IrDA Pulse Duration Baud Rate Pulse Duration (3/16) 2.4 Kb/s 78.13 µs 9.6 Kb/s 19.53 µs 19.2 Kb/s 9.77 µs 38.4 Kb/s 4.88 µs 57.6 Kb/s 3.26 µs 115.2 Kb/s 1.63 µs Figure 34-34 shows an example of character transmission. Figure 34-34. IrDA Modulation Start Bit Transmitter Output 0 Stop Bit Data Bits 1 0 1 0 0 1 1 0 1 TXD Bit Period 714 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 3 16 Bit Period 34.7.5.2 IrDA Baud Rate Table 34-12 gives some examples of CD values, baud rate error and pulse duration. Note that the requirement on the maximum acceptable error of ±1.87% must be met. Table 34-12. IrDA Baud Rate Error Peripheral Clock Baud Rate CD Baud Rate Error Pulse Time 3 686 400 115 200 2 0.00% 1.63 20 000 000 115 200 11 1.38% 1.63 32 768 000 115 200 18 1.25% 1.63 40 000 000 115 200 22 1.38% 1.63 3 686 400 57 600 4 0.00% 3.26 20 000 000 57 600 22 1.38% 3.26 32 768 000 57 600 36 1.25% 3.26 40 000 000 57 600 43 0.93% 3.26 3 686 400 38 400 6 0.00% 4.88 20 000 000 38 400 33 1.38% 4.88 32 768 000 38 400 53 0.63% 4.88 40 000 000 38 400 65 0.16% 4.88 3 686 400 19 200 12 0.00% 9.77 20 000 000 19 200 65 0.16% 9.77 32 768 000 19 200 107 0.31% 9.77 40 000 000 19 200 130 0.16% 9.77 3 686 400 9 600 24 0.00% 19.53 20 000 000 9 600 130 0.16% 19.53 32 768 000 9 600 213 0.16% 19.53 40 000 000 9 600 260 0.16% 19.53 3 686 400 2 400 96 0.00% 78.13 20 000 000 2 400 521 0.03% 78.13 32 768 000 2 400 853 0.04% 78.13 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 715 34.7.5.3 IrDA Demodulator The demodulator is based on the IrDA Receive filter comprised of an 8-bit down counter which is loaded with the value programmed in US_IF. When a falling edge is detected on the RXD pin, the Filter Counter starts counting down at the Master Clock (MCK) speed. If a rising edge is detected on the RXD pin, the counter stops and is reloaded with US_IF. If no rising edge is detected when the counter reaches 0, the input of the receiver is driven low during one bit time. Figure 34-35 illustrates the operations of the IrDA demodulator. Figure 34-35. IrDA Demodulator Operations MCK RXD Counter Value 6 Receiver Input 5 4 3 Pulse Rejected 2 6 6 5 4 3 2 1 0 Pulse Accepted As the IrDA mode uses the same logic as the ISO7816, note that the FI_DI_RATIO field in US_FIDI must be set to a value higher than 0 in order to assure IrDA communications operate correctly. 34.7.6 RS485 Mode The USART features the RS485 mode to enable line driver control. While operating in RS485 mode, the USART behaves as though in asynchronous or synchronous mode and configuration of all the parameters is possible. The difference is that the RTS pin is driven high when the transmitter is operating. The behavior of the RTS pin is controlled by the TXEMPTY bit. A typical connection of the USART to a RS485 bus is shown in Figure 34-36. Figure 34-36. Typical Connection to a RS485 Bus USART RXD TXD Differential Bus RTS The USART is set in RS485 mode by programming the USART_MODE field in the Mode Register (US_MR) to the value 0x1. The RTS pin is at a level inverse to the TXEMPTY bit. Significantly, the RTS pin remains high when a timeguard is programmed so that the line can remain driven after the last character completion. Figure 34-37 gives an example of the RTS waveform during a character transmission when the timeguard is enabled. 716 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 34-37. Example of RTS Drive with Timeguard TG = 4 Baud Rate Clock TXD Start D0 Bit D1 D2 D3 D4 D5 D6 D7 Parity Stop Bit Bit Write US_THR TXRDY TXEMPTY RTS SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 717 34.7.7 Modem Mode The USART features modem mode, which enables control of the signals: DTR (Data Terminal Ready), DSR (Data Set Ready), RTS (Request to Send), CTS (Clear to Send), DCD (Data Carrier Detect) and RI (Ring Indicator). While operating in modem mode, the USART behaves as a DTE (Data Terminal Equipment) as it drives DTR and RTS and can detect level change on DSR, DCD, CTS and RI. Setting the USART in modem mode is performed by writing the USART_MODE field in the Mode Register (US_MR) to the value 0x3. While operating in modem mode the USART behaves as though in asynchronous mode and all the parameter configurations are available. Table 34-13 gives the correspondence of the USART signals with modem connection standards. Table 34-13. Circuit References USART Pin V24 CCITT Direction TXD 2 103 From terminal to modem RTS 4 105 From terminal to modem DTR 20 108.2 From terminal to modem RXD 3 104 From modem to terminal CTS 5 106 From terminal to modem DSR 6 107 From terminal to modem DCD 8 109 From terminal to modem RI 22 125 From terminal to modem The control of the DTR output pin is performed by writing the Control Register (US_CR) with the DTRDIS and DTREN bits respectively to 1. The disable command forces the corresponding pin to its inactive level, i.e. high. The enable command forces the corresponding pin to its active level, i.e. low. RTS output pin is automatically controlled in this mode The level changes are detected on the RI, DSR, DCD and CTS pins. If an input change is detected, the RIIC, DSRIC, DCDIC and CTSIC bits in the Channel Status Register (US_CSR) are set respectively and can trigger an interrupt. The status is automatically cleared when US_CSR is read. Furthermore, the CTS automatically disables the transmitter when it is detected at its inactive state. If a character is being transmitted when the CTS rises, the character transmission is completed before the transmitter is actually disabled. 718 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.7.8 SPI Mode The Serial Peripheral Interface (SPI) Mode is a synchronous serial data link that provides communication with external devices in Master or Slave Mode. It also enables communication between processors if an external processor is connected to the system. The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to other SPIs. During a data transfer, one SPI system acts as the “master” which controls the data flow, while the other devices act as “slaves'' which have data shifted into and out by the master. Different CPUs can take turns being masters and one master may simultaneously shift data into multiple slaves. (Multiple Master Protocol is the opposite of Single Master Protocol, where one CPU is always the master while all of the others are always slaves.) However, only one slave may drive its output to write data back to the master at any given time. A slave device is selected when its NSS signal is asserted by the master. The USART in SPI Master mode can address only one SPI Slave because it can generate only one NSS signal. The SPI system consists of two data lines and two control lines:  Master Out Slave In (MOSI): This data line supplies the output data from the master shifted into the input of the slave.  Master In Slave Out (MISO): This data line supplies the output data from a slave to the input of the master.  Serial Clock (SCK): This control line is driven by the master and regulates the flow of the data bits. The master may transmit data at a variety of baud rates. The SCK line cycles once for each bit that is transmitted.  Slave Select (NSS): This control line allows the master to select or deselect the slave. 34.7.8.1 Modes of Operation The USART can operate in SPI Master Mode or in SPI Slave Mode. Operation in SPI Master Mode is programmed by writing to 0xE the USART_MODE field in the Mode Register. In this case the SPI lines must be connected as described below:  the MOSI line is driven by the output pin TXD  the MISO line drives the input pin RXD  the SCK line is driven by the output pin SCK  the NSS line is driven by the output pin RTS Operation in SPI Slave Mode is programmed by writing to 0xF the USART_MODE field in the Mode Register. In this case the SPI lines must be connected as described below:  the MOSI line drives the input pin RXD  the MISO line is driven by the output pin TXD  the SCK line drives the input pin SCK  the NSS line drives the input pin CTS In order to avoid unpredicted behavior, any change of the SPI Mode must be followed by a software reset of the transmitter and of the receiver (except the initial configuration after a hardware reset). (See Section 34.7.2 ”Receiver and Transmitter Control”). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 719 34.7.8.2 Baud Rate In SPI Mode, the baudrate generator operates in the same way as in USART synchronous mode: See “Baud Rate in Synchronous Mode or SPI Mode” on page 694. However, there are some restrictions: In SPI Master Mode:  the external clock SCK must not be selected (USCLKS ≠ 0x3), and the bit CLKO must be set to “1” in the Mode Register (US_MR), in order to generate correctly the serial clock on the SCK pin.  to obtain correct behavior of the receiver and the transmitter, the value programmed in CD must be superior or equal to 6.  if the internal clock divided (MCK/DIV) is selected, the value programmed in CD must be even to ensure a 50:50 mark/space ratio on the SCK pin, this value can be odd if the internal clock is selected (MCK). In SPI Slave Mode:  the external clock (SCK) selection is forced regardless of the value of the USCLKS field in the Mode Register (US_MR). Likewise, the value written in US_BRGR has no effect, because the clock is provided directly by the signal on the USART SCK pin.  to obtain correct behavior of the receiver and the transmitter, the external clock (SCK) frequency must be at least 6 times lower than the system clock. 34.7.8.3 Data Transfer Up to 9 data bits are successively shifted out on the TXD pin at each rising or falling edge (depending of CPOL and CPHA) of the programmed serial clock. There is no Start bit, no Parity bit and no Stop bit. The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register (US_MR). The 9 bits are selected by setting the MODE 9 bit regardless of the CHRL field. The MSB data bit is always sent first in SPI Mode (Master or Slave). Four combinations of polarity and phase are available for data transfers. The clock polarity is programmed with the CPOL bit in the Mode Register. The clock phase is programmed with the CPHA bit. These two parameters determine the edges of the clock signal upon which data is driven and sampled. Each of the two parameters has two possible states, resulting in four possible combinations that are incompatible with one another. Thus, a master/slave pair must use the same parameter pair values to communicate. If multiple slaves are used and fixed in different configurations, the master must reconfigure itself each time it needs to communicate with a different slave. Table 34-14. 720 SPI Bus Protocol Mode SPI Bus Protocol Mode CPOL CPHA 0 0 1 1 0 0 2 1 1 3 1 0 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 34-38. SPI Transfer Format (CPHA=1, 8 bits per transfer) SCK cycle (for reference) 1 2 3 4 6 5 7 8 SCK (CPOL = 0) SCK (CPOL = 1) MOSI SPI Master ->TXD SPI Slave -> RXD MISO SPI Master ->RXD SPI Slave -> TXD MSB MSB 6 5 4 3 2 1 LSB 6 5 4 3 2 1 LSB NSS SPI Master -> RTS SPI Slave -> CTS Figure 34-39. SPI Transfer Format (CPHA=0, 8 bits per transfer) SCK cycle (for reference) 1 2 3 4 5 8 7 6 SCK (CPOL = 0) SCK (CPOL = 1) MOSI SPI Master -> TXD SPI Slave -> RXD MSB 6 5 4 3 2 1 LSB MISO SPI Master -> RXD SPI Slave -> TXD MSB 6 5 4 3 2 1 LSB NSS SPI Master -> RTS SPI Slave -> CTS 34.7.8.4 Receiver and Transmitter Control See “Receiver and Transmitter Control” on page 696. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 721 34.7.8.5 Character Transmission The characters are sent by writing in the Transmit Holding Register (US_THR). An additional condition for transmitting a character can be added when the USART is configured in SPI master mode. In the USART_MR register, the value configured on INACK field can prevent any character transmission (even if US_THR has been written) while the receiver side is not ready (character not read). When INACK equals 0, the character is transmitted whatever the receiver status. If INACK is set to 1, the transmitter waits for the receiver holding register to be read before transmitting the character (RXRDY flag cleared), thus preventing any overflow (character loss) on the receiver side. The transmitter reports two status bits in the Channel Status Register (US_CSR): TXRDY (Transmitter Ready), which indicates that US_THR is empty and TXEMPTY, which indicates that all the characters written in US_THR have been processed. When the current character processing is completed, the last character written in US_THR is transferred into the Shift Register of the transmitter and US_THR becomes empty, thus TXRDY rises. Both TXRDY and TXEMPTY bits are low when the transmitter is disabled. Writing a character in US_THR while TXRDY is low has no effect and the written character is lost. If the USART is in SPI Slave Mode and if a character must be sent while the Transmit Holding Register (US_THR) is empty, the UNRE (Underrun Error) bit is set. The TXD transmission line stays at high level during all this time. The UNRE bit is cleared by writing the Control Register (US_CR) with the RSTSTA (Reset Status) bit to 1. In SPI Master Mode, the slave select line (NSS) is asserted at low level 1 Tbit (Time bit) before the transmission of the MSB bit and released at high level 1 Tbit after the transmission of the LSB bit. So, the slave select line (NSS) is always released between each character transmission and a minimum delay of 3 Tbits always inserted. However, in order to address slave devices supporting the CSAAT mode (Chip Select Active After Transfer), the slave select line (NSS) can be forced at low level by writing the Control Register (US_CR) with the RTSEN bit to 1. The slave select line (NSS) can be released at high level only by writing the Control Register (US_CR) with the RTSDIS bit to 1 (for example, when all data have been transferred to the slave device). In SPI Slave Mode, the transmitter does not require a falling edge of the slave select line (NSS) to initiate a character transmission but only a low level. However, this low level must be present on the slave select line (NSS) at least 1 Tbit before the first serial clock cycle corresponding to the MSB bit. 34.7.8.6 Character Reception When a character reception is completed, it is transferred to the Receive Holding Register (US_RHR) and the RXRDY bit in the Status Register (US_CSR) rises. If a character is completed while RXRDY is set, the OVRE (Overrun Error) bit is set. The last character is transferred into US_RHR and overwrites the previous one. The OVRE bit is cleared by writing the Control Register (US_CR) with the RSTSTA (Reset Status) bit to 1. To ensure correct behavior of the receiver in SPI Slave Mode, the master device sending the frame must ensure a minimum delay of 1 Tbit between each character transmission. The receiver does not require a falling edge of the slave select line (NSS) to initiate a character reception but only a low level. However, this low level must be present on the slave select line (NSS) at least 1 Tbit before the first serial clock cycle corresponding to the MSB bit. 34.7.8.7 Receiver Timeout Because the receiver baudrate clock is active only during data transfers in SPI Mode, a receiver timeout is impossible in this mode, whatever the Time-out value is (field TO) in the Time-out Register (US_RTOR). 722 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.7.9 Test Modes WRITE BUFFER READ BUFFER DATA 0 DATA 0 NACT = SUBSCRIBE APB bus | | | | APB bus USART3 LIN CONTROLLER (Peripheral) DMA Controller TXRDY DATA N | | | | USART3 LIN CONTROLLER (Peripheral) DMA Controller RXRDY DATA N The USART can be programmed to operate in three different test modes. The internal loopback capability allows on-board diagnostics. In the loopback mode the USART interface pins are disconnected or not and reconfigured for loopback internally or externally. 34.7.9.1 Normal Mode Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD pin. Figure 34-40. Normal Mode Configuration RXD Receiver TXD Transmitter 34.7.9.2 Automatic Echo Mode Automatic echo mode allows bit-by-bit retransmission. When a bit is received on the RXD pin, it is sent to the TXD pin, as shown in Figure 34-41. Programming the transmitter has no effect on the TXD pin. The RXD pin is still connected to the receiver input, thus the receiver remains active. Figure 34-41. Automatic Echo Mode Configuration RXD Receiver TXD Transmitter 34.7.9.3 Local Loopback Mode Local loopback mode connects the output of the transmitter directly to the input of the receiver, as shown in Figure 34-42. The TXD and RXD pins are not used. The RXD pin has no effect on the receiver and the TXD pin is continuously driven high, as in idle state. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 723 Figure 34-42. Local Loopback Mode Configuration RXD Receiver 1 Transmitter TXD 34.7.9.4 Remote Loopback Mode Remote loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 34-43. The transmitter and the receiver are disabled and have no effect. This mode allows bit-by-bit retransmission. Figure 34-43. Remote Loopback Mode Configuration Receiver 1 RXD TXD Transmitter 724 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.7.10 Write Protection Registers To prevent any single software error that may corrupt USART behavior, certain address spaces can be writeprotected by setting the WPEN bit in the USART Write Protect Mode Register (US_WPMR). If a write access to the protected registers is detected, then the WPVS flag in the USART Write Protect Status Register (US_WPSR) is set and the field WPVSRC indicates in which register the write access has been attempted. The WPVS flag is reset by writing the USART Write Protect Mode Register (US_WPMR) with the appropriate access key, WPKEY. The protected registers are:  “USART Mode Register”  “USART Baud Rate Generator Register”  “USART Receiver Time-out Register”  “USART Transmitter Timeguard Register”  “USART FI DI RATIO Register”  “USART IrDA FILTER Register”  “USART Manchester Configuration Register” SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 725 34.8 Universal Synchronous Asynchronous Receiver Transmitter (USART) User Interface Table 34-15. Register Mapping Offset Register Name Access Reset 0x0000 Control Register US_CR Write-only – 0x0004 Mode Register US_MR Read-write – 0x0008 Interrupt Enable Register US_IER Write-only – 0x000C Interrupt Disable Register US_IDR Write-only – 0x0010 Interrupt Mask Register US_IMR Read-only 0x0 0x0014 Channel Status Register US_CSR Read-only – 0x0018 Receiver Holding Register US_RHR Read-only 0x0 0x001C Transmitter Holding Register US_THR Write-only – 0x0020 Baud Rate Generator Register US_BRGR Read-write 0x0 0x0024 Receiver Time-out Register US_RTOR Read-write 0x0 0x0028 Transmitter Timeguard Register US_TTGR Read-write 0x0 – – – 0x2C - 0x3C 0x0040 FI DI Ratio Register US_FIDI Read-write 0x174 0x0044 Number of Errors Register US_NER Read-only – 0x0048 Reserved – – – 0x004C IrDA Filter Register US_IF Read-write 0x0 0x0050 Manchester Encoder Decoder Register US_MAN Read-write 0x30011004 0xE4 Write Protect Mode Register US_WPMR Read-write 0x0 0xE8 Write Protect Status Register US_WPSR Read-only 0x0 Reserved – – – Reserved for PDC Registers – – – 0x5C - 0xFC 0x100 - 0x128 726 Reserved SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.8.1 USART Control Register Name: US_CR Address: 0x40090000 (0), 0x40094000 (1), 0x40098000 (2), 0x4009C000 (3) Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RTSDIS/RCS 18 RTSEN/FCS 17 DTRDIS 16 DTREN 15 RETTO 14 RSTNACK 13 RSTIT 12 SENDA 11 STTTO 10 STPBRK 9 STTBRK 8 RSTSTA 7 TXDIS 6 TXEN 5 RXDIS 4 RXEN 3 RSTTX 2 RSTRX 1 – 0 – • RSTRX: Reset Receiver 0: No effect. 1: Resets the receiver. • RSTTX: Reset Transmitter 0: No effect. 1: Resets the transmitter. • RXEN: Receiver Enable 0: No effect. 1: Enables the receiver, if RXDIS is 0. • RXDIS: Receiver Disable 0: No effect. 1: Disables the receiver. • TXEN: Transmitter Enable 0: No effect. 1: Enables the transmitter if TXDIS is 0. • TXDIS: Transmitter Disable 0: No effect. 1: Disables the transmitter. • RSTSTA: Reset Status Bits 0: No effect. 1: Resets the status bits PARE, FRAME, OVRE, MANERR, UNRE and RXBRK in US_CSR. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 727 • STTBRK: Start Break 0: No effect. 1: Starts transmission of a break after the characters present in US_THR and the Transmit Shift Register have been transmitted. No effect if a break is already being transmitted. • STPBRK: Stop Break 0: No effect. 1: Stops transmission of the break after a minimum of one character length and transmits a high level during 12-bit periods. No effect if no break is being transmitted. • STTTO: Start Time-out 0: No effect. 1: Starts waiting for a character before clocking the time-out counter. Resets the status bit TIMEOUT in US_CSR. • SENDA: Send Address 0: No effect. 1: In Multidrop Mode only, the next character written to the US_THR is sent with the address bit set. • RSTIT: Reset Iterations 0: No effect. 1: Resets ITERATION in US_CSR. No effect if the ISO7816 is not enabled. • RSTNACK: Reset Non Acknowledge 0: No effect 1: Resets NACK in US_CSR. • RETTO: Rearm Time-out 0: No effect 1: Restart Time-out • DTREN: Data Terminal Ready Enable 0: No effect. 1: Drives the pin DTR to 0. • DTRDIS: Data Terminal Ready Disable 0: No effect. 1: Drives the pin DTR to 1. • RTSEN: Request to Send Enable 0: No effect. 1: Drives the pin RTS to 0. 728 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • FCS: Force SPI Chip Select – Applicable if USART operates in SPI Master Mode (USART_MODE = 0xE): FCS = 0: No effect. FCS = 1: Forces the Slave Select Line NSS (RTS pin) to 0, even if USART is no transmitting, in order to address SPI slave devices supporting the CSAAT Mode (Chip Select Active After Transfer). • RTSDIS: Request to Send Disable 0: No effect. 1: Drives the pin RTS to 1. • RCS: Release SPI Chip Select – Applicable if USART operates in SPI Master Mode (USART_MODE = 0xE): RCS = 0: No effect. RCS = 1: Releases the Slave Select Line NSS (RTS pin). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 729 34.8.2 USART Mode Register Name: US_MR Address: 0x40090004 (0), 0x40094004 (1), 0x40098004 (2), 0x4009C004 (3) Access: Read-write 31 ONEBIT 30 MODSYNC 29 MAN 28 FILTER 27 – 26 25 MAX_ITERATION 24 23 INVDATA 22 VAR_SYNC 21 DSNACK 20 INACK 19 OVER 18 CLKO 17 MODE9 16 MSBF/CPOL 15 14 13 12 11 10 PAR 9 8 SYNC/CPHA 4 3 2 1 0 CHMODE 7 NBSTOP 6 5 CHRL USCLKS USART_MODE This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 753. • USART_MODE Value Name Description 0x0 NORMAL Normal mode 0x1 RS485 0x2 HW_HANDSHAKING 0x3 MODEM 0x4 IS07816_T_0 IS07816 Protocol: T = 0 0x6 IS07816_T_1 IS07816 Protocol: T = 1 0x8 IRDA 0xE SPI_MASTER SPI Master 0xF SPI_SLAVE SPI Slave RS485 Hardware Handshaking Modem IrDA • USCLKS: Clock Selection Value Name Description 0 MCK Master Clock MCK is selected 1 DIV Internal Clock Divided MCK/DIV (DIV=8) is selected 3 SCK Serial Clock SLK is selected • CHRL: Character Length. 730 Value Name Description 0 5_BIT Character length is 5 bits 1 6_BIT Character length is 6 bits 2 7_BIT Character length is 7 bits 3 8_BIT Character length is 8 bits SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • SYNC: Synchronous Mode Select 0: USART operates in Asynchronous Mode. 1: USART operates in Synchronous Mode. • CPHA: SPI Clock Phase – Applicable if USART operates in SPI Mode (USART_MODE = 0xE or 0xF): CPHA = 0: Data is changed on the leading edge of SPCK and captured on the following edge of SPCK. CPHA = 1: Data is captured on the leading edge of SPCK and changed on the following edge of SPCK. CPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. CPHA is used with CPOL to produce the required clock/data relationship between master and slave devices. • PAR: Parity Type Value Name Description 0 EVEN Even parity 1 ODD Odd parity 2 SPACE Parity forced to 0 (Space) 3 MARK Parity forced to 1 (Mark) 4 NO 6 MULTIDROP No parity Multidrop mode • NBSTOP: Number of Stop Bits Value Name Description 0 1_BIT 1 stop bit 1 1_5_BIT 2 2_BIT 1.5 stop bit (SYNC = 0) or reserved (SYNC = 1) 2 stop bits • CHMODE: Channel Mode Value Name Description 0 NORMAL Normal Mode 1 AUTOMATIC 2 LOCAL_LOOPBACK 3 REMOTE_LOOPBACK Automatic Echo. Receiver input is connected to the TXD pin. Local Loopback. Transmitter output is connected to the Receiver Input. Remote Loopback. RXD pin is internally connected to the TXD pin. • MSBF: Bit Order 0: Least Significant Bit is sent/received first. 1: Most Significant Bit is sent/received first. • CPOL: SPI Clock Polarity – Applicable if USART operates in SPI Mode (Slave or Master, USART_MODE = 0xE or 0xF): CPOL = 0: The inactive state value of SPCK is logic level zero. CPOL = 1: The inactive state value of SPCK is logic level one. CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with CPHA to produce the required clock/data relationship between master and slave devices. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 731 • MODE9: 9-bit Character Length 0: CHRL defines character length. 1: 9-bit character length. • CLKO: Clock Output Select 0: The USART does not drive the SCK pin. 1: The USART drives the SCK pin if USCLKS does not select the external clock SCK. • OVER: Oversampling Mode 0: 16x Oversampling. 1: 8x Oversampling. • INACK: Inhibit Non Acknowledge 0: The NACK is generated. 1: The NACK is not generated. Note: In SPI master mode, if INACK = 0 the character transmission starts as soon as a character is written into US_THR register (assuming TXRDY was set). When INACK is 1, an additional condition must be met. The character transmission starts when a character is written and only if RXRDY flag is cleared (Receiver Holding Register has been read). • DSNACK: Disable Successive NACK 0: NACK is sent on the ISO line as soon as a parity error occurs in the received character (unless INACK is set). 1: Successive parity errors are counted up to the value specified in the MAX_ITERATION field. These parity errors generate a NACK on the ISO line. As soon as this value is reached, no additional NACK is sent on the ISO line. The flag ITERATION is asserted. • INVDATA: INverted Data 0: The data field transmitted on TXD line is the same as the one written in US_THR register or the content read in US_RHR is the same as RXD line. Normal mode of operation. 1: The data field transmitted on TXD line is inverted (voltage polarity only) compared to the value written on US_THR register or the content read in US_RHR is inverted compared to what is received on RXD line (or ISO7816 IO line). Inverted Mode of operation, useful for contactless card application. To be used with configuration bit MSBF. • VAR_SYNC: Variable Synchronization of Command/Data Sync Start Frame Delimiter 0: User defined configuration of command or data sync field depending on MODSYNC value. 1: The sync field is updated when a character is written into US_THR register. • MAX_ITERATION Defines the maximum number of iterations in mode ISO7816, protocol T= 0. • FILTER: Infrared Receive Line Filter 0: The USART does not filter the receive line. 1: The USART filters the receive line using a three-sample filter (1/16-bit clock) (2 over 3 majority). • MAN: Manchester Encoder/Decoder Enable 0: Manchester Encoder/Decoder are disabled. 1: Manchester Encoder/Decoder are enabled. 732 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • MODSYNC: Manchester Synchronization Mode 0:The Manchester Start bit is a 0 to 1 transition 1: The Manchester Start bit is a 1 to 0 transition. • ONEBIT: Start Frame Delimiter Selector 0: Start Frame delimiter is COMMAND or DATA SYNC. 1: Start Frame delimiter is One Bit. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 733 34.8.3 USART Interrupt Enable Register Name: US_IER Address: 0x40090008 (0), 0x40094008 (1), 0x40098008 (2), 0x4009C008 (3) Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 MANE 23 – 22 – 21 – 20 – 19 CTSIC 18 DCDIC 17 DSRIC 16 RIIC 15 – 14 – 13 NACK 12 RXBUFF 11 TXBUFE 10 ITER/UNRE 9 TXEMPTY 8 TIMEOUT 7 PARE 6 FRAME 5 OVRE 4 ENDTX 3 ENDRX 2 RXBRK 1 TXRDY 0 RXRDY 0: No effect 1: Enables the corresponding interrupt. • RXRDY: RXRDY Interrupt Enable • TXRDY: TXRDY Interrupt Enable • RXBRK: Receiver Break Interrupt Enable • ENDRX: End of Receive Transfer Interrupt Enable • ENDTX: End of Transmit Interrupt Enable • OVRE: Overrun Error Interrupt Enable • FRAME: Framing Error Interrupt Enable • PARE: Parity Error Interrupt Enable • TIMEOUT: Time-out Interrupt Enable • TXEMPTY: TXEMPTY Interrupt Enable • ITER: Max number of Repetitions Reached • UNRE: SPI Underrun Error • TXBUFE: Buffer Empty Interrupt Enable • RXBUFF: Buffer Full Interrupt Enable • NACK: Non AcknowledgeInterrupt Enable • RIIC: Ring Indicator Input Change Enable • DSRIC: Data Set Ready Input Change Enable 734 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • DCDIC: Data Carrier Detect Input Change Interrupt Enable • CTSIC: Clear to Send Input Change Interrupt Enable • MANE: Manchester Error Interrupt Enable SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 735 34.8.4 USART Interrupt Disable Register Name: US_IDR Address: 0x4009000C (0), 0x4009400C (1), 0x4009800C (2), 0x4009C00C (3) Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 MANE 23 – 22 – 21 – 20 – 19 CTSIC 18 DCDIC 17 DSRIC 16 RIIC 15 – 14 – 13 NACK 12 RXBUFF 11 TXBUFE 10 ITER/UNRE 9 TXEMPTY 8 TIMEOUT 7 PARE 6 FRAME 5 OVRE 4 ENDTX 3 ENDRX 2 RXBRK 1 TXRDY 0 RXRDY 0: No effect 1: Disables the corresponding interrupt. • RXRDY: RXRDY Interrupt Disable • TXRDY: TXRDY Interrupt Disable • RXBRK: Receiver Break Interrupt Disable • ENDRX: End of Receive Transfer Interrupt Disable • ENDTX: End of Transmit Interrupt Disable • OVRE: Overrun Error Interrupt Disable • FRAME: Framing Error Interrupt Disable • PARE: Parity Error Interrupt Disable • TIMEOUT: Time-out Interrupt Disable • TXEMPTY: TXEMPTY Interrupt Disable • ITER: Max number of Repetitions Reached Disable • UNRE: SPI Underrun Error Disable • TXBUFE: Buffer Empty Interrupt Disable • RXBUFF: Buffer Full Interrupt Disable • NACK: Non AcknowledgeInterrupt Disable • RIIC: Ring Indicator Input Change Disable • DSRIC: Data Set Ready Input Change Disable 736 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • DCDIC: Data Carrier Detect Input Change Interrupt Disable • CTSIC: Clear to Send Input Change Interrupt Disable • MANE: Manchester Error Interrupt Disable SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 737 34.8.5 USART Interrupt Mask Register Name: US_IMR Address: 0x40090010 (0), 0x40094010 (1), 0x40098010 (2), 0x4009C010 (3) Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 MANE 23 – 22 – 21 – 20 – 19 CTSIC 18 DCDIC 17 DSRIC 16 RIIC 15 – 14 – 13 NACK 12 RXBUFF 11 TXBUFE 10 ITER/UNRE 9 TXEMPTY 8 TIMEOUT 7 PARE 6 FRAME 5 OVRE 4 ENDTX 3 ENDRX 2 RXBRK 1 TXRDY 0 RXRDY 0: The corresponding interrupt is not enabled. 1: The corresponding interrupt is enabled. • RXRDY: RXRDY Interrupt Mask • TXRDY: TXRDY Interrupt Mask • RXBRK: Receiver Break Interrupt Mask • ENDRX: End of Receive Transfer Interrupt Mask • ENDTX: End of Transmit Interrupt Mask • OVRE: Overrun Error Interrupt Mask • FRAME: Framing Error Interrupt Mask • PARE: Parity Error Interrupt Mask • TIMEOUT: Time-out Interrupt Mask • TXEMPTY: TXEMPTY Interrupt Mask • ITER: Max number of Repetitions Reached Mask • UNRE: SPI Underrun Error Mask • TXBUFE: Buffer Empty Interrupt Mask • RXBUFF: Buffer Full Interrupt Mask • NACK: Non AcknowledgeInterrupt Mask • RIIC: Ring Indicator Input Change Mask • DSRIC: Data Set Ready Input Change Mask 738 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • DCDIC: Data Carrier Detect Input Change Interrupt Mask • CTSIC: Clear to Send Input Change Interrupt Mask • MANE: Manchester Error Interrupt Mask SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 739 34.8.6 USART Channel Status Register Name: US_CSR Address: 0x40090014 (0), 0x40094014 (1), 0x40098014 (2), 0x4009C014 (3) Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 MANERR 23 CTS 22 DCD 21 DSR 20 RI 19 CTSIC 18 DCDIC 17 DSRIC 16 RIIC 15 – 14 – 13 NACK 12 RXBUFF 11 TXBUFE 10 ITER/UNRE 9 TXEMPTY 8 TIMEOUT 7 PARE 6 FRAME 5 OVRE 4 ENDTX 3 ENDRX 2 RXBRK 1 TXRDY 0 RXRDY • RXRDY: Receiver Ready 0: No complete character has been received since the last read of US_RHR or the receiver is disabled. If characters were being received when the receiver was disabled, RXRDY changes to 1 when the receiver is enabled. 1: At least one complete character has been received and US_RHR has not yet been read. • TXRDY: Transmitter Ready 0: A character is in the US_THR waiting to be transferred to the Transmit Shift Register, or an STTBRK command has been requested, or the transmitter is disabled. As soon as the transmitter is enabled, TXRDY becomes 1. 1: There is no character in the US_THR. • RXBRK: Break Received/End of Break 0: No Break received or End of Break detected since the last RSTSTA. 1: Break Received or End of Break detected since the last RSTSTA. • ENDRX: End of Receiver Transfer 0: The End of Transfer signal from the Receive PDC channel is inactive. 1: The End of Transfer signal from the Receive PDC channel is active. • ENDTX: End of Transmitter Transfer 0: The End of Transfer signal from the Transmit PDC channel is inactive. 1: The End of Transfer signal from the Transmit PDC channel is active. • OVRE: Overrun Error 0: No overrun error has occurred since the last RSTSTA. 1: At least one overrun error has occurred since the last RSTSTA. • FRAME: Framing Error 0: No stop bit has been detected low since the last RSTSTA. 1: At least one stop bit has been detected low since the last RSTSTA. 740 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • PARE: Parity Error 0: No parity error has been detected since the last RSTSTA. 1: At least one parity error has been detected since the last RSTSTA. • TIMEOUT: Receiver Time-out 0: There has not been a time-out since the last Start Time-out command (STTTO in US_CR) or the Time-out Register is 0. 1: There has been a time-out since the last Start Time-out command (STTTO in US_CR). • TXEMPTY: Transmitter Empty 0: There are characters in either US_THR or the Transmit Shift Register, or the transmitter is disabled. 1: There are no characters in US_THR, nor in the Transmit Shift Register. • ITER: Max number of Repetitions Reached 0: Maximum number of repetitions has not been reached since the last RSTSTA. 1: Maximum number of repetitions has been reached since the last RSTSTA. • UNRE: SPI Underrun Error – Applicable if USART operates in SPI Slave Mode (USART_MODE = 0xF): UNRE = 0: No SPI underrun error has occurred since the last RSTSTA. UNRE = 1: At least one SPI underrun error has occurred since the last RSTSTA. • TXBUFE: Transmission Buffer Empty 0: The signal Buffer Empty from the Transmit PDC channel is inactive. 1: The signal Buffer Empty from the Transmit PDC channel is active. • RXBUFF: Reception Buffer Full 0: The signal Buffer Full from the Receive PDC channel is inactive. 1: The signal Buffer Full from the Receive PDC channel is active. • NACK: Non AcknowledgeInterrupt 0: Non Acknowledge has not been detected since the last RSTNACK. 1: At least one Non Acknowledge has been detected since the last RSTNACK. • RIIC: Ring Indicator Input Change Flag 0: No input change has been detected on the RI pin since the last read of US_CSR. 1: At least one input change has been detected on the RI pin since the last read of US_CSR. • DSRIC: Data Set Ready Input Change Flag 0: No input change has been detected on the DSR pin since the last read of US_CSR. 1: At least one input change has been detected on the DSR pin since the last read of US_CSR. • DCDIC: Data Carrier Detect Input Change Flag 0: No input change has been detected on the DCD pin since the last read of US_CSR. 1: At least one input change has been detected on the DCD pin since the last read of US_CSR. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 741 • CTSIC: Clear to Send Input Change Flag 0: No input change has been detected on the CTS pin since the last read of US_CSR. 1: At least one input change has been detected on the CTS pin since the last read of US_CSR. • RI: Image of RI Input 0: RI is set to 0. 1: RI is set to 1. • DSR: Image of DSR Input 0: DSR is set to 0 1: DSR is set to 1. • DCD: Image of DCD Input 0: DCD is set to 0. 1: DCD is set to 1. • CTS: Image of CTS Input 0: CTS is set to 0. 1: CTS is set to 1. • MANERR: Manchester Error 0: No Manchester error has been detected since the last RSTSTA. 1: At least one Manchester error has been detected since the last RSTSTA. 742 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.8.7 USART Receive Holding Register Name: US_RHR Address: 0x40090018 (0), 0x40094018 (1), 0x40098018 (2), 0x4009C018 (3) Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 RXSYNH 14 – 13 – 12 – 11 – 10 – 9 – 8 RXCHR 7 6 5 4 3 2 1 0 RXCHR • RXCHR: Received Character Last character received if RXRDY is set. • RXSYNH: Received Sync 0: Last Character received is a Data. 1: Last Character received is a Command. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 743 34.8.8 USART Transmit Holding Register Name: US_THR Address: 0x4009001C (0), 0x4009401C (1), 0x4009801C (2), 0x4009C01C (3) Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 TXSYNH 14 – 13 – 12 – 11 – 10 – 9 – 8 TXCHR 7 6 5 4 3 2 1 0 TXCHR • TXCHR: Character to be Transmitted Next character to be transmitted after the current character if TXRDY is not set. • TXSYNH: Sync Field to be transmitted 0: The next character sent is encoded as a data. Start Frame Delimiter is DATA SYNC. 1: The next character sent is encoded as a command. Start Frame Delimiter is COMMAND SYNC. 744 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.8.9 USART Baud Rate Generator Register Name: US_BRGR Address: 0x40090020 (0), 0x40094020 (1), 0x40098020 (2), 0x4009C020 (3) Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 17 FP 16 15 14 13 12 11 10 9 8 3 2 1 0 CD 7 6 5 4 CD This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 753. • CD: Clock Divider USART_MODE ≠ ISO7816 SYNC = 1 or USART_MODE = SPI (Master or Slave) SYNC = 0 CD OVER = 0 OVER = 1 0 1 to 65535 USART_MODE = ISO7816 Baud Rate Clock Disabled Baud Rate = Baud Rate = Baud Rate = Selected Clock/(16*CD) Selected Clock/(8*CD) Selected Clock /CD Baud Rate = Selected Clock/(FI_DI_RATIO*CD) • FP: Fractional Part 0: Fractional divider is disabled. 1 - 7: Baudrate resolution, defined by FP x 1/8. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 745 34.8.10 USART Receiver Time-out Register Name: US_RTOR Address: 0x40090024 (0), 0x40094024 (1), 0x40098024 (2), 0x4009C024 (3) Access: Read-write 31 30 29 28 27 26 25 24 – – – – – – – – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 14 13 12 11 10 9 8 3 2 1 0 TO 7 6 5 4 TO This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 753. • TO: Time-out Value 0: The Receiver Time-out is disabled. 1 - 65535: The Receiver Time-out is enabled and the Time-out delay is TO x Bit Period. 746 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.8.11 USART Transmitter Timeguard Register Name: US_TTGR Address: 0x40090028 (0), 0x40094028 (1), 0x40098028 (2), 0x4009C028 (3) Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 6 5 4 3 2 1 0 TG This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 753. • TG: Timeguard Value 0: The Transmitter Timeguard is disabled. 1 - 255: The Transmitter timeguard is enabled and the timeguard delay is TG x Bit Period. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 747 34.8.12 USART FI DI RATIO Register Name: US_FIDI Address: 0x40090040 (0), 0x40094040 (1), 0x40098040 (2), 0x4009C040 (3) Access: Read-write Reset Value: 0x174 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 9 FI_DI_RATIO 8 7 6 5 4 3 2 1 0 FI_DI_RATIO This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 753. • FI_DI_RATIO: FI Over DI Ratio Value 0: If ISO7816 mode is selected, the Baud Rate Generator generates no signal. 1 - 2047: If ISO7816 mode is selected, the Baud Rate is the clock provided on SCK divided by FI_DI_RATIO. 748 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.8.13 USART Number of Errors Register Name: US_NER Address: 0x40090044 (0), 0x40094044 (1), 0x40098044 (2), 0x4009C044 (3) Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 6 5 4 3 2 1 0 NB_ERRORS • NB_ERRORS: Number of Errors Total number of errors that occurred during an ISO7816 transfer. This register automatically clears when read. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 749 34.8.14 USART IrDA FILTER Register Name: US_IF Address: 0x4009004C (0), 0x4009404C (1), 0x4009804C (2), 0x4009C04C (3) Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 6 5 4 3 2 1 0 IRDA_FILTER This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 753. • IRDA_FILTER: IrDA Filter Sets the filter of the IrDA demodulator. 750 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.8.15 USART Manchester Configuration Register Name: US_MAN Address: 0x40090050 (0), 0x40094050 (1), 0x40098050 (2), 0x4009C050 (3) Access: Read-write 31 – 30 DRIFT 29 1 28 RX_MPOL 27 – 26 – 25 23 – 22 – 21 – 20 – 19 18 17 15 – 14 – 13 – 12 TX_MPOL 11 – 10 – 9 7 – 6 – 5 – 4 – 3 2 1 24 RX_PP 16 RX_PL 8 TX_PP 0 TX_PL This register can only be written if the WPEN bit is cleared in “USART Write Protect Mode Register” on page 753. • TX_PL: Transmitter Preamble Length 0: The Transmitter Preamble pattern generation is disabled 1 - 15: The Preamble Length is TX_PL x Bit Period • TX_PP: Transmitter Preamble Pattern The following values assume that TX_MPOL field is not set: Value Name Description 00 ALL_ONE The preamble is composed of ‘1’s 01 ALL_ZERO The preamble is composed of ‘0’s 10 ZERO_ONE The preamble is composed of ‘01’s 11 ONE_ZERO The preamble is composed of ‘10’s • TX_MPOL: Transmitter Manchester Polarity 0: Logic Zero is coded as a zero-to-one transition, Logic One is coded as a one-to-zero transition. 1: Logic Zero is coded as a one-to-zero transition, Logic One is coded as a zero-to-one transition. • RX_PL: Receiver Preamble Length 0: The receiver preamble pattern detection is disabled 1 - 15: The detected preamble length is RX_PL x Bit Period • RX_PP: Receiver Preamble Pattern detected The following values assume that RX_MPOL field is not set: Value Name Description 00 ALL_ONE The preamble is composed of ‘1’s 01 ALL_ZERO The preamble is composed of ‘0’s 10 ZERO_ONE The preamble is composed of ‘01’s 11 ONE_ZERO The preamble is composed of ‘10’s SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 751 • RX_MPOL: Receiver Manchester Polarity 0: Logic Zero is coded as a zero-to-one transition, Logic One is coded as a one-to-zero transition. 1: Logic Zero is coded as a one-to-zero transition, Logic One is coded as a zero-to-one transition. • DRIFT: Drift compensation 0: The USART can not recover from an important clock drift 1: The USART can recover from clock drift. The 16X clock mode must be enabled. 752 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 34.8.16 USART Write Protect Mode Register Name: US_WPMR Address: 0x400900E4 (0), 0x400940E4 (1), 0x400980E4 (2), 0x4009C0E4 (3) Access: Read-write Reset: See Table 34-15 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 WPKEY 23 22 21 20 WPKEY 15 14 13 12 WPKEY 7 6 5 4 3 2 1 0 — — — — — — — WPEN • WPEN: Write Protect Enable 0 = Disables the Write Protect if WPKEY corresponds to 0x555341 (“USA” in ASCII). 1 = Enables the Write Protect if WPKEY corresponds to 0x555341 (“USA” in ASCII). Protects the registers: • “USART Mode Register” on page 730 • “USART Baud Rate Generator Register” on page 745 • “USART Receiver Time-out Register” on page 746 • “USART Transmitter Timeguard Register” on page 747 • “USART FI DI RATIO Register” on page 748 • “USART IrDA FILTER Register” on page 750 • “USART Manchester Configuration Register” on page 751 • WPKEY: Write Protect KEY Should be written at value 0x555341 (“USA” in ASCII). Writing any other value in this field aborts the write operation of the WPEN bit. Always reads as 0. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 753 34.8.17 USART Write Protect Status Register Name: US_WPSR Address: 0x400900E8 (0), 0x400940E8 (1), 0x400980E8 (2), 0x4009C0E8 (3) Access: Read-only Reset: See Table 34-15 31 30 29 28 27 26 25 24 — — — — — — — — 23 22 21 20 19 18 17 16 11 10 9 8 WPVSRC 15 14 13 12 WPVSRC 7 6 5 4 3 2 1 0 — — — — — — — WPVS • WPVS: Write Protect Violation Status 0 = No Write Protect Violation has occurred since the last read of the US_WPSR register. 1 = A Write Protect Violation has occurred since the last read of the US_WPSR register. If this violation is an unauthorized attempt to write a protected register, the associated violation is reported into field WPVSRC. • WPVSRC: Write Protect Violation Source When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write access has been attempted. Note: Reading US_WPSR automatically clears all fields. 754 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35. Timer Counter (TC) 35.1 Description A Timer Counter (TC) module includes three identical TC channels. The number of implemented TC modules is device-specific. Each TC channel can be independently programmed to perform a wide range of functions including frequency measurement, event counting, interval measurement, pulse generation, delay timing and pulse width modulation. Each channel has three external clock inputs, five internal clock inputs and two multi-purpose input/output signals which can be configured by the user. Each channel drives an internal interrupt signal which can be programmed to generate processor interrupts. The TC embeds a quadrature decoder (QDEC) connected in front of the timers and driven by TIOA0, TIOB0 and TIOB1 inputs. When enabled, the QDEC performs the input lines filtering, decoding of quadrature signals and connects to the timers/counters in order to read the position and speed of the motor through the user interface. The TC block has two global registers which act upon all TC channels: 35.2  Block Control Register (TC_BCR)—allows channels to be started simultaneously with the same instruction  Block Mode Register (TC_BMR)—defines the external clock inputs for each channel, allowing them to be chained Embedded Characteristics  Total number of TC channels: 9  TC channel size: 16-bit  Wide range of functions including:   ̶ Frequency measurement ̶ Event counting ̶ Interval measurement ̶ Pulse generation ̶ Delay timing ̶ Pulse Width Modulation ̶ Up/down capabilities ̶ Quadrature decoder Each channel is user-configurable and contains: ̶ Three external clock inputs ̶ Five Internal clock inputs ̶ Two multi-purpose input/output signals acting as trigger event Internal interrupt signal SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 755 35.3 Block Diagram Table 35-1. Timer Counter Clock Assignment Name Definition TIMER_CLOCK1 MCK/2 TIMER_CLOCK2 MCK/8 TIMER_CLOCK3 MCK/32 TIMER_CLOCK4 MCK/128 TIMER_CLOCK5 SLCK Note: Figure 35-1. 1. When SLCK is selected for Peripheral Clock (CSS = 0 in PMC Master Clock Register), SLCK input is equivalent to Peripheral Clock. Timer Counter Block Diagram Parallel I/O Controller TIMER_CLOCK1 TCLK0 TIMER_CLOCK2 TIOA1 TIOA2 TIMER_CLOCK3 TCLK1 TIMER_CLOCK4 XC0 XC1 Timer/Counter Channel 0 TIOA TIOA0 TIOB0 TIOA0 TIOB TCLK2 TIOB0 XC2 TIMER_CLOCK5 TC0XC0S SYNC TCLK0 TCLK1 TCLK2 INT0 TCLK0 TCLK1 XC0 TIOA0 XC1 Timer/Counter Channel 1 TIOA TIOA1 TIOB1 TIOA1 TIOB TIOA2 TCLK2 TIOB1 XC2 TC1XC1S TCLK0 XC0 TCLK1 XC1 TCLK2 XC2 SYNC Timer/Counter Channel 2 INT1 TIOA TIOA2 TIOB2 TIOA2 TIOB TIOA0 TIOA1 TC2XC2S TIOB2 SYNC INT2 Timer Counter Interrupt Controller 756 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 35-2. Signal Name Description Block/Channel Signal Name XC0, XC1, XC2 Channel Signal External Clock Inputs TIOA Capture Mode: Timer Counter Input Waveform Mode: Timer Counter Output TIOB Capture Mode: Timer Counter Input Waveform Mode: Timer Counter Input/Output INT SYNC 35.4 Description Interrupt Signal Output (internal signal) Synchronization Input Signal (from configuration register) Pin Name List Table 35-3. TC Pin List Pin Name Description Type TCLK0–TCLK2 External Clock Input Input TIOA0–TIOA2 I/O Line A I/O TIOB0–TIOB2 I/O Line B I/O SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 757 35.5 Product Dependencies 35.5.1 I/O Lines The pins used for interfacing the compliant external devices may be multiplexed with PIO lines. The programmer must first program the PIO controllers to assign the TC pins to their peripheral functions. Table 35-4. I/O Lines Instance Signal I/O Line Peripheral TC0 TCLK0 PA2 A TC0 TCLK1 PB4 A TC0 TCLK2 PA26 B TC0 TIOA0 PA1 A TC0 TIOA1 PB5 A TC0 TIOA2 PA30 B TC0 TIOB0 PA0 A TC0 TIOB1 PB6 A TC0 TIOB2 PA31 B 35.5.2 Power Management The TC is clocked through the Power Management Controller (PMC), thus the programmer must first configure the PMC to enable the Timer Counter clock of each channel. 35.5.3 Interrupt Sources The TC has an interrupt line per channel connected to the interrupt controller. Handling the TC interrupt requires programming the interrupt controller before configuring the TC. Table 35-5. 758 Peripheral IDs Instance ID TC0 22 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.6 Functional Description 35.6.1 Description All channels of the Timer Counter are independent and identical in operation except when the QDEC is enabled. The registers for channel programming are listed in Table 35-6 “Register Mapping”. 35.6.2 16-bit Counter Each 16-bit channel is organized around a 16-bit counter. The value of the counter is incremented at each positive edge of the selected clock. When the counter has reached the value 216-1 and passes to zero, an overflow occurs and the COVFS bit in the TC Status Register (TC_SR) is set. The current value of the counter is accessible in real time by reading the TC Counter Value Register (TC_CV). The counter can be reset by a trigger. In this case, the counter value passes to zero on the next valid edge of the selected clock. 35.6.3 Clock Selection At block level, input clock signals of each channel can either be connected to the external inputs TCLK0, TCLK1 or TCLK2, or be connected to the internal I/O signals TIOA0, TIOA1 or TIOA2 for chaining by programming the TC Block Mode Register (TC_BMR). See Figure 35-2. Each channel can independently select an internal or external clock source for its counter:  External clock signals(1): XC0, XC1 or XC2  Internal clock signals: MCK/2, MCK/8, MCK/32, MCK/128, SLCK This selection is made by the TCCLKS bits in the TC Channel Mode Register (TC_CMR). The selected clock can be inverted with the CLKI bit in the TC_CMR. This allows counting on the opposite edges of the clock. The burst function allows the clock to be validated when an external signal is high. The BURST parameter in the TC_CMR defines this signal (none, XC0, XC1, XC2). See Figure 35-3. Note: 1. In all cases, if an external clock is used, the duration of each of its levels must be longer than the peripheral clock period. The external clock frequency must be at least 2.5 times lower than the peripheral clock. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 759 Figure 35-2. Clock Chaining Selection TC0XC0S Timer/Counter Channel 0 TCLK0 TIOA1 XC0 TIOA2 TIOA0 XC1 = TCLK1 XC2 = TCLK2 TIOB0 SYNC TC1XC1S Timer/Counter Channel 1 TCLK1 XC0 = TCLK0 TIOA0 TIOA1 XC1 TIOA2 XC2 = TCLK2 TIOB1 SYNC Timer/Counter Channel 2 TC2XC2S XC0 = TCLK0 TCLK2 TIOA2 XC1 = TCLK1 TIOA0 XC2 TIOB2 TIOA1 SYNC Figure 35-3. Clock Selection TCCLKS CLKI TIMER_CLOCK1 Synchronous Edge Detection TIMER_CLOCK2 TIMER_CLOCK3 Selected Clock TIMER_CLOCK4 TIMER_CLOCK5 XC0 XC1 XC2 Peripheral Clock BURST 1 760 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.6.4 Clock Control The clock of each counter can be controlled in two different ways: it can be enabled/disabled and started/stopped. See Figure 35-4.  The clock can be enabled or disabled by the user with the CLKEN and the CLKDIS commands in the TC Channel Control Register (TC_CCR). In Capture mode it can be disabled by an RB load event if LDBDIS is set to 1 in the TC_CMR. In Waveform mode, it can be disabled by an RC Compare event if CPCDIS is set to 1 in TC_CMR. When disabled, the start or the stop actions have no effect: only a CLKEN command in the TC_CCR can re-enable the clock. When the clock is enabled, the CLKSTA bit is set in the TC_SR.  The clock can also be started or stopped: a trigger (software, synchro, external or compare) always starts the clock. The clock can be stopped by an RB load event in Capture mode (LDBSTOP = 1 in TC_CMR) or an RC compare event in Waveform mode (CPCSTOP = 1 in TC_CMR). The start and the stop commands are effective only if the clock is enabled. Figure 35-4. Clock Control Selected Clock Trigger CLKSTA Q Q S CLKEN CLKDIS S R R Counter Clock Stop Event Disable Event 35.6.5 Operating Modes Each channel can operate independently in two different modes:  Capture mode provides measurement on signals.  Waveform mode provides wave generation. The TC operating mode is programmed with the WAVE bit in the TC_CMR. In Capture mode, TIOA and TIOB are configured as inputs. In Waveform mode, TIOA is always configured to be an output and TIOB is an output if it is not selected to be the external trigger. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 761 35.6.6 Trigger A trigger resets the counter and starts the counter clock. Three types of triggers are common to both modes, and a fourth external trigger is available to each mode. Regardless of the trigger used, it will be taken into account at the following active edge of the selected clock. This means that the counter value can be read differently from zero just after a trigger, especially when a low frequency signal is selected as the clock. The following triggers are common to both modes:  Software Trigger: Each channel has a software trigger, available by setting SWTRG in TC_CCR.  SYNC: Each channel has a synchronization signal SYNC. When asserted, this signal has the same effect as a software trigger. The SYNC signals of all channels are asserted simultaneously by writing TC_BCR (Block Control) with SYNC set.  Compare RC Trigger: RC is implemented in each channel and can provide a trigger when the counter value matches the RC value if CPCTRG is set in the TC_CMR. The channel can also be configured to have an external trigger. In Capture mode, the external trigger signal can be selected between TIOA and TIOB. In Waveform mode, an external event can be programmed on one of the following signals: TIOB, XC0, XC1 or XC2. This external event can then be programmed to perform a trigger by setting bit ENETRG in the TC_CMR. If an external trigger is used, the duration of the pulses must be longer than the peripheral clock period in order to be detected. 35.6.7 Capture Mode Capture mode is entered by clearing the WAVE bit in the TC_CMR. Capture mode allows the TC channel to perform measurements such as pulse timing, frequency, period, duty cycle and phase on TIOA and TIOB signals which are considered as inputs. Figure 35-5 shows the configuration of the TC channel when programmed in Capture mode. 35.6.8 Capture Registers A and B Registers A and B (RA and RB) are used as capture registers. They can be loaded with the counter value when a programmable event occurs on the signal TIOA. The LDRA field in the TC_CMR defines the TIOA selected edge for the loading of register A, and the LDRB field defines the TIOA selected edge for the loading of Register B. RA is loaded only if it has not been loaded since the last trigger or if RB has been loaded since the last loading of RA. RB is loaded only if RA has been loaded since the last trigger or the last loading of RB. Loading RA or RB before the read of the last value loaded sets the Overrun Error Flag (LOVRS bit) in the TC_SR. In this case, the old value is overwritten. 35.6.9 Trigger Conditions In addition to the SYNC signal, the software trigger and the RC compare trigger, an external trigger can be defined. The ABETRG bit in the TC_CMR selects TIOA or TIOB input signal as an external trigger . The External Trigger Edge Selection parameter (ETRGEDG field in TC_CMR) defines the edge (rising, falling, or both) detected to generate an external trigger. If ETRGEDG = 0 (none), the external trigger is disabled. 762 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 MTIOA MTIOB 1 ABETRG CLKI If RA is not loaded or RB is Loaded Edge Detector ETRGEDG SWTRG Timer/Counter Channel BURST Peripheral Clock Synchronous Edge Detection S R OVF LDRB Edge Detector Edge Detector Capture Register A LDBSTOP R S CLKEN LDRA If RA is Loaded CPCTRG Counter RESET Trig CLK Q Q CLKSTA LDBDIS Capture Register B CLKDIS TC1_SR TIOA TIOB SYNC XC2 XC1 XC0 TIMER_CLOCK5 TIMER_CLOCK4 TIMER_CLOCK3 TIMER_CLOCK2 TIMER_CLOCK1 TCCLKS Compare RC = Register C COVFS LDRBS INT Figure 35-5. Capture Mode LOVRS CPCS ETRGS LDRAS TC1_IMR Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 SAM3U Series [DATASHEET] 763 35.6.10 Waveform Mode Waveform mode is entered by setting the TC_CMRx.WAVE bit. In Waveform mode, the TC channel generates one or two PWM signals with the same frequency and independently programmable duty cycles, or generates different types of one-shot or repetitive pulses. In this mode, TIOA is configured as an output and TIOB is defined as an output if it is not used as an external event (EEVT parameter in TC_CMR). Figure 35-6 shows the configuration of the TC channel when programmed in Waveform operating mode. 35.6.11 Waveform Selection Depending on the WAVSEL parameter in TC_CMR, the behavior of TC_CV varies. With any selection, TC_RA, TC_RB and TC_RC can all be used as compare registers. RA Compare is used to control the TIOA output, RB Compare is used to control the TIOB output (if correctly configured) and RC Compare is used to control TIOA and/or TIOB outputs. 764 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1 EEVT BURST ENETRG CLKI Timer/Counter Channel Edge Detector EEVTEDG SWTRG Peripheral Clock Synchronous Edge Detection Trig CLK R S OVF WAVSEL RESET Counter WAVSEL Q Compare RA = Register A Q CLKSTA Compare RC = Compare RB = CPCSTOP CPCDIS Register C CLKDIS Register B R S CLKEN CPAS INT BSWTRG BEEVT BCPB BCPC ASWTRG AEEVT ACPA ACPC Output Controller TIOB SYNC XC2 XC1 XC0 TIMER_CLOCK5 TIMER_CLOCK4 TIMER_CLOCK3 TIMER_CLOCK2 TIMER_CLOCK1 TCCLKS TIOB MTIOB TIOA MTIOA Figure 35-6. Waveform Mode Output Controller CPCS CPBS COVFS TC1_SR ETRGS TC1_IMR Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 SAM3U Series [DATASHEET] 765 35.6.11.1 WAVSEL = 00 When WAVSEL = 00, the value of TC_CV is incremented from 0 to 216-1. Once 216-1 has been reached, the value of TC_CV is reset. Incrementation of TC_CV starts again and the cycle continues. See Figure 35-7. An external event trigger or a software trigger can reset the value of TC_CV. It is important to note that the trigger may occur at any time. See Figure 35-8. RC Compare cannot be programmed to generate a trigger in this configuration. At the same time, RC Compare can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the counter clock (CPCDIS = 1 in TC_CMR). Figure 35-7. WAVSEL = 00 without trigger Counter Value Counter cleared by compare match with 0xFFFF 0xFFFF RC RB RA Time Waveform Examples TIOB TIOA Figure 35-8. WAVSEL = 00 with Trigger Counter Value Counter cleared by compare match with 0xFFFF 0xFFFF RC Counter cleared by trigger RB RA Waveform Examples TIOB TIOA 766 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Time 35.6.11.2 WAVSEL = 10 When WAVSEL = 10, the value of TC_CV is incremented from 0 to the value of RC, then automatically reset on a RC Compare. Once the value of TC_CV has been reset, it is then incremented and so on. See Figure 35-9. It is important to note that TC_CV can be reset at any time by an external event or a software trigger if both are programmed correctly. See Figure 35-10. In addition, RC Compare can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the counter clock (CPCDIS = 1 in TC_CMR). Figure 35-9. WAVSEL = 10 without Trigger Counter Value 2n-1 (n = counter size) Counter cleared by compare match with RC RC RB RA Time Waveform Examples TIOB TIOA Figure 35-10. WAVSEL = 10 with Trigger Counter Value 2n-1 (n = counter size) Counter cleared by compare match with RC Counter cleared by trigger RC RB RA Waveform Examples Time TIOB TIOA SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 767 35.6.11.3 WAVSEL = 01 When WAVSEL = 01, the value of TC_CV is incremented from 0 to 216-1 . Once 216-1 is reached, the value of TC_CV is decremented to 0, then re-incremented to 216-1 and so on. See Figure 35-11. A trigger such as an external event or a software trigger can modify TC_CV at any time. If a trigger occurs while TC_CV is incrementing, TC_CV then decrements. If a trigger is received while TC_CV is decrementing, TC_CV then increments. See Figure 35-12. RC Compare cannot be programmed to generate a trigger in this configuration. At the same time, RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock (CPCDIS = 1). Figure 35-11. WAVSEL = 01 without Trigger Counter Value Counter decremented by compare match with 0xFFFF 0xFFFF RC RB RA Time Waveform Examples TIOB TIOA Figure 35-12. WAVSEL = 01 with Trigger Counter Value Counter decremented by compare match with 0xFFFF 0xFFFF Counter decremented by trigger RC RB Counter incremented by trigger RA Waveform Examples TIOB TIOA 768 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Time 35.6.11.4 WAVSEL = 11 When WAVSEL = 11, the value of TC_CV is incremented from 0 to RC. Once RC is reached, the value of TC_CV is decremented to 0, then re-incremented to RC and so on. See Figure 35-13. A trigger such as an external event or a software trigger can modify TC_CV at any time. If a trigger occurs while TC_CV is incrementing, TC_CV then decrements. If a trigger is received while TC_CV is decrementing, TC_CV then increments. See Figure 35-14. RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock (CPCDIS = 1). Figure 35-13. WAVSEL = 11 without Trigger Counter Value 2n-1 (n = counter size) Counter decremented by compare match with RC RC RB RA Time Waveform Examples TIOB TIOA Figure 35-14. WAVSEL = 11 with Trigger Counter Value 2n-1 (n = counter size) RC RB Counter decremented by compare match with RC Counter decremented by trigger Counter incremented by trigger RA Waveform Examples Time TIOB TIOA SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 769 35.6.12 External Event/Trigger Conditions An external event can be programmed to be detected on one of the clock sources (XC0, XC1, XC2) or TIOB. The external event selected can then be used as a trigger. The EEVT parameter in TC_CMR selects the external trigger. The EEVTEDG parameter defines the trigger edge for each of the possible external triggers (rising, falling or both). If EEVTEDG is cleared (none), no external event is defined. If TIOB is defined as an external event signal (EEVT = 0), TIOB is no longer used as an output and the compare register B is not used to generate waveforms and subsequently no IRQs. In this case the TC channel can only generate a waveform on TIOA. When an external event is defined, it can be used as a trigger by setting bit ENETRG in the TC_CMR. As in Capture mode, the SYNC signal and the software trigger are also available as triggers. RC Compare can also be used as a trigger depending on the parameter WAVSEL. 35.6.13 Output Controller The output controller defines the output level changes on TIOA and TIOB following an event. TIOB control is used only if TIOB is defined as output (not as an external event). The following events control TIOA and TIOB: software trigger, external event and RC compare. RA compare controls TIOA and RB compare controls TIOB. Each of these events can be programmed to set, clear or toggle the output as defined in the corresponding parameter in TC_CMR. 35.6.14 Quadrature Decoder 35.6.14.1 Description The quadrature decoder (QDEC) is driven by TIOA0, TIOB0, TIOB1 input pins and drives the timer/counter of channel 0 and 1. Channel 2 can be used as a time base in case of speed measurement requirements (refer to Figure 35-15). When writing a 0 to bit QDEN of the TC_BMR, the QDEC is bypassed and the IO pins are directly routed to the timer counter function. See TIOA0 and TIOB0 are to be driven by the two dedicated quadrature signals from a rotary sensor mounted on the shaft of the off-chip motor. A third signal from the rotary sensor can be processed through pin TIOB1 and is typically dedicated to be driven by an index signal if it is provided by the sensor. This signal is not required to decode the quadrature signals PHA, PHB. Field TCCLKS of TC_CMRx must be configured to select XC0 input (i.e., 0x101). Field TC0XC0S has no effect as soon as the QDEC is enabled. Either speed or position/revolution can be measured. Position channel 0 accumulates the edges of PHA, PHB input signals giving a high accuracy on motor position whereas channel 1 accumulates the index pulses of the sensor, therefore the number of rotations. Concatenation of both values provides a high level of precision on motion system position. In Speed mode, position cannot be measured but revolution can be measured. Inputs from the rotary sensor can be filtered prior to down-stream processing. Accommodation of input polarity, phase definition and other factors are configurable. Interruptions can be generated on different events. A compare function (using TC_RC) is available on channel 0 (speed/position) or channel 1 (rotation) and can generate an interrupt by means of the CPCS flag in the TC_SRx. 770 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 35-15. Predefined Connection of the Quadrature Decoder with Timer Counters Reset pulse SPEEDEN Quadrature Decoder 1 1 (Filter + Edge Detect + QD) TIOA Timer/Counter Channel 0 TIOA0 QDEN PHEdges 1 TIOB 1 XC0 TIOB0 TIOA0 PHA TIOB0 PHB TIOB1 IDX XC0 Speed/Position QDEN Index 1 TIOB TIOB1 1 XC0 Timer/Counter Channel 1 XC0 Rotation Direction Timer/Counter Channel 2 Speed Time Base SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 771 35.6.14.2 Input Pre-processing Input pre-processing consists of capabilities to take into account rotary sensor factors such as polarities and phase definition followed by configurable digital filtering. Each input can be negated and swapping PHA, PHB is also configurable. The MAXFILT field in the TC_BMR is used to configure a minimum duration for which the pulse is stated as valid. When the filter is active, pulses with a duration lower than MAXFILT +1 × tperipheral clock ns are not passed to downstream logic. Figure 35-16. Input Stage Input Pre-Processing MAXFILT SWAP 1 PHA Filter TIOA0 MAXFILT > 0 1 PHedge Direction and Edge Detection INVA 1 PHB Filter TIOB0 1 DIR 1 IDX INVB 1 1 IDX Filter TIOB1 IDXPHB INVIDX Input filtering can efficiently remove spurious pulses that might be generated by the presence of particulate contamination on the optical or magnetic disk of the rotary sensor. Spurious pulses can also occur in environments with high levels of electro-magnetic interference. Or, simply if vibration occurs even when rotation is fully stopped and the shaft of the motor is in such a position that the beginning of one of the reflective or magnetic bars on the rotary sensor disk is aligned with the light or magnetic (Hall) receiver cell of the rotary sensor. Any vibration can make the PHA, PHB signals toggle for a short duration. 772 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 35-17. Filtering Examples MAXFILT = 2 Peripheral Clock particulate contamination PHA,B Filter Out Optical/Magnetic disk strips PHA PHB motor shaft stopped in such a position that rotary sensor cell is aligned with an edge of the disk rotation stop PHA PHB Edge area due to system vibration PHB Resulting PHA, PHB electrical waveforms PHA stop mechanical shock on system PHB vibration PHA, PHB electrical waveforms after filtering PHA PHB SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 773 35.6.14.3 Direction Status and Change Detection After filtering, the quadrature signals are analyzed to extract the rotation direction and edges of the two quadrature signals detected in order to be counted by timer/counter logic downstream. The direction status can be directly read at anytime in the TC_QISR. The polarity of the direction flag status depends on the configuration written in TC_BMR. INVA, INVB, INVIDX, SWAP modify the polarity of DIR flag. Any change in rotation direction is reported in the TC_QISR and can generate an interrupt. The direction change condition is reported as soon as two consecutive edges on a phase signal have sampled the same value on the other phase signal and there is an edge on the other signal. The two consecutive edges of one phase signal sampling the same value on other phase signal is not sufficient to declare a direction change, for the reason that particulate contamination may mask one or more reflective bars on the optical or magnetic disk of the sensor. Refer to Figure 35-18 for waveforms. Figure 35-18. Rotation Change Detection Direction Change under normal conditions PHA change condition Report Time PHB DIR DIRCHG No direction change due to particulate contamination masking a reflective bar missing pulse PHA same phase PHB DIR spurious change condition (if detected in a simple way) DIRCHG The direction change detection is disabled when QDTRANS is set in the TC_BMR. In this case, the DIR flag report must not be used. A quadrature error is also reported by the QDEC via the QERR flag in the TC_QISR. This error is reported if the time difference between two edges on PHA, PHB is lower than a predefined value. This predefined value is configurable and corresponds to (MAXFILT + 1) × tperipheral clock ns. After being filtered there is no reason to have two edges closer than (MAXFILT + 1) × tperipheral clock ns under normal mode of operation. 774 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 35-19. Quadrature Error Detection MAXFILT = 2 Peripheral Clock Abnormally formatted optical disk strips (theoretical view) PHA PHB strip edge inaccurary due to disk etching/printing process PHA PHB resulting PHA, PHB electrical waveforms PHA Even with an abnorrmaly formatted disk, there is no occurence of PHA, PHB switching at the same time. PHB duration < MAXFILT QERR MAXFILT must be tuned according to several factors such as the peripheral clock frequency, type of rotary sensor and rotation speed to be achieved. 35.6.14.4 Position and Rotation Measurement When the POSEN bit is set in the TC_BMR, the motor axis position is processed on channel 0 (by means of the PHA, PHB edge detections) and the number of motor revolutions are recorded on channel 1 if the IDX signal is provided on the TIOB1 input. The position measurement can be read in the TC_CV0 register and the rotation measurement can be read in the TC_CV1 register. Channel 0 and 1 must be configured in Capture mode (TC_CMR0.WAVE = 0). ‘Rising edge’ must be selected as the External Trigger Edge (TC_CMR.ETRGEDG = 0x01) and ‘TIOA’ must be selected as the External Trigger (TC_CMR.ABETRG = 0x1). In parallel, the number of edges are accumulated on timer/counter channel 0 and can be read on the TC_CV0 register. Therefore, the accurate position can be read on both TC_CV registers and concatenated to form a 32-bit word. The timer/counter channel 0 is cleared for each increment of IDX count value. Depending on the quadrature signals, the direction is decoded and allows to count up or down in timer/counter channels 0 and 1. The direction status is reported on TC_QISR. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 775 35.6.14.5 Speed Measurement When SPEEDEN is set in the TC_BMR, the speed measure is enabled on channel 0. A time base must be defined on channel 2 by writing the TC_RC2 period register. Channel 2 must be configured in Waveform mode (WAVE bit set) in TC_CMR2. The WAVSEL field must be defined with 0x10 to clear the counter by comparison and matching with TC_RC value. Field ACPC must be defined at 0x11 to toggle TIOA output. This time base is automatically fed back to TIOA of channel 0 when QDEN and SPEEDEN are set. Channel 0 must be configured in Capture mode (WAVE = 0 in TC_CMR0). The ABETRG bit of TC_CMR0 must be configured at 1 to select TIOA as a trigger for this channel. EDGTRG must be set to 0x01, to clear the counter on a rising edge of the TIOA signal and field LDRA must be set accordingly to 0x01, to load TC_RA0 at the same time as the counter is cleared (LDRB must be set to 0x01). As a consequence, at the end of each time base period the differentiation required for the speed calculation is performed. The process must be started by configuring bits CLKEN and SWTRG in the TC_CCR. The speed can be read on field RA in TC_RA0. Channel 1 can still be used to count the number of revolutions of the motor. 776 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7 Timer Counter (TC) User Interface Table 35-6. Register Mapping Offset(1) Register Name Access Reset 0x00 + channel * 0x40 + 0x00 Channel Control Register TC_CCR Write-only – 0x00 + channel * 0x40 + 0x04 Channel Mode Register TC_CMR Read/Write 0 0x00 + channel * 0x40 + 0x08 Reserved – – – 0x00 + channel * 0x40 + 0x0C Reserved – – – 0x00 + channel * 0x40 + 0x10 Counter Value TC_CV 0x00 + channel * 0x40 + 0x14 Register A TC_RA Read-only Read/Write 0 (2) 0 (2) 0 0x00 + channel * 0x40 + 0x18 Register B TC_RB 0x00 + channel * 0x40 + 0x1C Register C TC_RC Read/Write 0 0x00 + channel * 0x40 + 0x20 Status Register TC_SR Read-only 0 0x00 + channel * 0x40 + 0x24 Interrupt Enable Register TC_IER Write-only – 0x00 + channel * 0x40 + 0x28 Interrupt Disable Register TC_IDR Write-only – 0x00 + channel * 0x40 + 0x2C Interrupt Mask Register TC_IMR Read-only 0 0xC0 Block Control Register TC_BCR Write-only – 0xC4 Block Mode Register TC_BMR Read/Write 0 0xC8 QDEC Interrupt Enable Register TC_QIER Write-only – 0xCC QDEC Interrupt Disable Register TC_QIDR Write-only – 0xD0 QDEC Interrupt Mask Register TC_QIMR Read-only 0 0xD4 QDEC Interrupt Status Register TC_QISR Read-only 0 0xD8 Reserved – – – 0xE4 Reserved – – – 0xE8–0xFC Reserved – – – Notes: Read/Write 1. Channel index ranges from 0 to 2. 2. Read-only if TC_CMRx.WAVE = 0 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 777 35.7.1 TC Channel Control Register Name: TC_CCRx [x=0..2] Address: 0x40080000 (0)[0], 0x40080040 (0)[1], 0x40080080 (0)[2] Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 SWTRG 1 CLKDIS 0 CLKEN • CLKEN: Counter Clock Enable Command 0: No effect. 1: Enables the clock if CLKDIS is not 1. • CLKDIS: Counter Clock Disable Command 0: No effect. 1: Disables the clock. • SWTRG: Software Trigger Command 0: No effect. 1: A software trigger is performed: the counter is reset and the clock is started. 778 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.2 TC Channel Mode Register: Capture Mode Name: TC_CMRx [x=0..2] (CAPTURE_MODE) Address: 0x40080004 (0)[0], 0x40080044 (0)[1], 0x40080084 (0)[2] Access: Read/Write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 18 17 16 15 WAVE 14 CPCTRG 13 – 12 – 11 – 10 ABETRG 9 7 LDBDIS 6 LDBSTOP 5 4 3 CLKI 2 1 TCCLKS LDRB BURST LDRA 8 ETRGEDG 0 • TCCLKS: Clock Selection Value Name Description 0 TIMER_CLOCK1 Clock selected: internal MCK/2 clock signal (from PMC) 1 TIMER_CLOCK2 Clock selected: internal MCK/8 clock signal (from PMC) 2 TIMER_CLOCK3 Clock selected: internal MCK/32 clock signal (from PMC) 3 TIMER_CLOCK4 Clock selected: internal MCK/128 clock signal (from PMC) 4 TIMER_CLOCK5 Clock selected: internal SLCK clock signal (from PMC) 5 XC0 Clock selected: XC0 6 XC1 Clock selected: XC1 7 XC2 Clock selected: XC2 • CLKI: Clock Invert 0: Counter is incremented on rising edge of the clock. 1: Counter is incremented on falling edge of the clock. • BURST: Burst Signal Selection Value Name Description 0 NONE The clock is not gated by an external signal. 1 XC0 XC0 is ANDed with the selected clock. 2 XC1 XC1 is ANDed with the selected clock. 3 XC2 XC2 is ANDed with the selected clock. • LDBSTOP: Counter Clock Stopped with RB Loading 0: Counter clock is not stopped when RB loading occurs. 1: Counter clock is stopped when RB loading occurs. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 779 • LDBDIS: Counter Clock Disable with RB Loading 0: Counter clock is not disabled when RB loading occurs. 1: Counter clock is disabled when RB loading occurs. • ETRGEDG: External Trigger Edge Selection Value Name Description 0 NONE The clock is not gated by an external signal. 1 RISING Rising edge 2 FALLING Falling edge 3 EDGE Each edge • ABETRG: TIOA or TIOB External Trigger Selection 0: TIOB is used as an external trigger. 1: TIOA is used as an external trigger. • CPCTRG: RC Compare Trigger Enable 0: RC Compare has no effect on the counter and its clock. 1: RC Compare resets the counter and starts the counter clock. • WAVE: Waveform Mode 0: Capture mode is enabled. 1: Capture mode is disabled (Waveform mode is enabled). • LDRA: RA Loading Edge Selection Value Name Description 0 NONE None 1 RISING Rising edge of TIOA 2 FALLING Falling edge of TIOA 3 EDGE Each edge of TIOA • LDRB: RB Loading Edge Selection 780 Value Name Description 0 NONE None 1 RISING Rising edge of TIOA 2 FALLING Falling edge of TIOA 3 EDGE Each edge of TIOA SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.3 TC Channel Mode Register: Waveform Mode Name: TC_CMRx [x=0..2] (WAVEFORM_MODE) Address: 0x40080004 (0)[0], 0x40080044 (0)[1], 0x40080084 (0)[2] Access: Read/Write 31 30 29 BSWTRG 23 28 27 BEEVT 22 21 ASWTRG 20 14 13 7 CPCDIS 6 CPCSTOP WAVSEL 25 24 BCPB 19 AEEVT 15 WAVE 26 BCPC 18 17 16 ACPC 12 ENETRG 11 4 3 CLKI 5 BURST ACPA 10 9 EEVT 8 EEVTEDG 2 1 TCCLKS 0 • TCCLKS: Clock Selection Value Name Description 0 TIMER_CLOCK1 Clock selected: internal MCK/2 clock signal (from PMC) 1 TIMER_CLOCK2 Clock selected: internal MCK/8 clock signal (from PMC) 2 TIMER_CLOCK3 Clock selected: internal MCK/32 clock signal (from PMC) 3 TIMER_CLOCK4 Clock selected: internal MCK/128 clock signal (from PMC) 4 TIMER_CLOCK5 Clock selected: internal SLCK clock signal (from PMC) 5 XC0 Clock selected: XC0 6 XC1 Clock selected: XC1 7 XC2 Clock selected: XC2 • CLKI: Clock Invert 0: Counter is incremented on rising edge of the clock. 1: Counter is incremented on falling edge of the clock. • BURST: Burst Signal Selection Value Name Description 0 NONE The clock is not gated by an external signal. 1 XC0 XC0 is ANDed with the selected clock. 2 XC1 XC1 is ANDed with the selected clock. 3 XC2 XC2 is ANDed with the selected clock. • CPCSTOP: Counter Clock Stopped with RC Compare 0: Counter clock is not stopped when counter reaches RC. 1: Counter clock is stopped when counter reaches RC. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 781 • CPCDIS: Counter Clock Disable with RC Compare 0: Counter clock is not disabled when counter reaches RC. 1: Counter clock is disabled when counter reaches RC. • EEVTEDG: External Event Edge Selection Value Name Description 0 NONE None 1 RISING Rising edge 2 FALLING Falling edge 3 EDGE Each edge • EEVT: External Event Selection Signal selected as external event. Value Note: Name Description 0 TIOB (1) TIOB Direction TIOB Input 1 XC0 XC0 Output 2 XC1 XC1 Output 3 XC2 XC2 Output 1. If TIOB is chosen as the external event signal, it is configured as an input and no longer generates waveforms and subsequently no IRQs. • ENETRG: External Event Trigger Enable 0: The external event has no effect on the counter and its clock. 1: The external event resets the counter and starts the counter clock. Note: Whatever the value programmed in ENETRG, the selected external event only controls the TIOA output and TIOB if not used as input (trigger event input or other input used). • WAVSEL: Waveform Selection Value Name Description 0 UP UP mode without automatic trigger on RC Compare 1 UPDOWN UPDOWN mode without automatic trigger on RC Compare 2 UP_RC UP mode with automatic trigger on RC Compare 3 UPDOWN_RC UPDOWN mode with automatic trigger on RC Compare • WAVE: Waveform Mode 0: Waveform mode is disabled (Capture mode is enabled). 1: Waveform mode is enabled. • ACPA: RA Compare Effect on TIOA 782 Value Name Description 0 NONE None 1 SET Set 2 CLEAR Clear 3 TOGGLE Toggle SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • ACPC: RC Compare Effect on TIOA Value Name Description 0 NONE None 1 SET Set 2 CLEAR Clear 3 TOGGLE Toggle • AEEVT: External Event Effect on TIOA Value Name Description 0 NONE None 1 SET Set 2 CLEAR Clear 3 TOGGLE Toggle • ASWTRG: Software Trigger Effect on TIOA Value Name Description 0 NONE None 1 SET Set 2 CLEAR Clear 3 TOGGLE Toggle • BCPB: RB Compare Effect on TIOB Value Name Description 0 NONE None 1 SET Set 2 CLEAR Clear 3 TOGGLE Toggle • BCPC: RC Compare Effect on TIOB Value Name Description 0 NONE None 1 SET Set 2 CLEAR Clear 3 TOGGLE Toggle • BEEVT: External Event Effect on TIOB Value Name Description 0 NONE None 1 SET Set 2 CLEAR Clear 3 TOGGLE Toggle SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 783 • BSWTRG: Software Trigger Effect on TIOB 784 Value Name Description 0 NONE None 1 SET Set 2 CLEAR Clear 3 TOGGLE Toggle SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.4 TC Counter Value Register Name: TC_CVx [x=0..2] Address: 0x40080010 (0)[0], 0x40080050 (0)[1], 0x40080090 (0)[2] Access: Read-only 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 CV 23 22 21 20 CV 15 14 13 12 CV 7 6 5 4 CV • CV: Counter Value CV contains the counter value in real time. IMPORTANT: For 16-bit channels, CV field size is limited to register bits 15:0. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 785 35.7.5 TC Register A Name: TC_RAx [x=0..2] Address: 0x40080014 (0)[0], 0x40080054 (0)[1], 0x40080094 (0)[2] Access: Read-only if TC_CMRx.WAVE = 0, Read/Write if TC_CMRx.WAVE = 1 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 RA 23 22 21 20 RA 15 14 13 12 RA 7 6 5 4 RA • RA: Register A RA contains the Register A value in real time. IMPORTANT: For 16-bit channels, RA field size is limited to register bits 15:0. 786 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.6 TC Register B Name: TC_RBx [x=0..2] Address: 0x40080018 (0)[0], 0x40080058 (0)[1], 0x40080098 (0)[2] Access: Read-only if TC_CMRx.WAVE = 0, Read/Write if TC_CMRx.WAVE = 1 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 RB 23 22 21 20 RB 15 14 13 12 RB 7 6 5 4 RB • RB: Register B RB contains the Register B value in real time. IMPORTANT: For 16-bit channels, RB field size is limited to register bits 15:0. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 787 35.7.7 TC Register C Name: TC_RCx [x=0..2] Address: 0x4008001C (0)[0], 0x4008005C (0)[1], 0x4008009C (0)[2] Access: Read/Write 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 RC 23 22 21 20 RC 15 14 13 12 RC 7 6 5 4 RC • RC: Register C RC contains the Register C value in real time. IMPORTANT: For 16-bit channels, RC field size is limited to register bits 15:0. 788 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.8 TC Status Register Name: TC_SRx [x=0..2] Address: 0x40080020 (0)[0], 0x40080060 (0)[1], 0x400800A0 (0)[2] Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 MTIOB 17 MTIOA 16 CLKSTA 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 ETRGS 6 LDRBS 5 LDRAS 4 CPCS 3 CPBS 2 CPAS 1 LOVRS 0 COVFS • COVFS: Counter Overflow Status (cleared on read) 0: No counter overflow has occurred since the last read of the Status Register. 1: A counter overflow has occurred since the last read of the Status Register. • LOVRS: Load Overrun Status (cleared on read) 0: Load overrun has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1. 1: RA or RB have been loaded at least twice without any read of the corresponding register since the last read of the Status Register, if TC_CMRx.WAVE = 0. • CPAS: RA Compare Status (cleared on read) 0: RA Compare has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 0. 1: RA Compare has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 1. • CPBS: RB Compare Status (cleared on read) 0: RB Compare has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 0. 1: RB Compare has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 1. • CPCS: RC Compare Status (cleared on read) 0: RC Compare has not occurred since the last read of the Status Register. 1: RC Compare has occurred since the last read of the Status Register. • LDRAS: RA Loading Status (cleared on read) 0: RA Load has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1. 1: RA Load has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 0. • LDRBS: RB Loading Status (cleared on read) 0: RB Load has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1. 1: RB Load has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 0. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 789 • ETRGS: External Trigger Status (cleared on read) 0: External trigger has not occurred since the last read of the Status Register. 1: External trigger has occurred since the last read of the Status Register. • CLKSTA: Clock Enabling Status 0: Clock is disabled. 1: Clock is enabled. • MTIOA: TIOA Mirror 0: TIOA is low. If TC_CMRx.WAVE = 0, this means that TIOA pin is low. If TC_CMRx.WAVE = 1, this means that TIOA is driven low. 1: TIOA is high. If TC_CMRx.WAVE = 0, this means that TIOA pin is high. If TC_CMRx.WAVE = 1, this means that TIOA is driven high. • MTIOB: TIOB Mirror 0: TIOB is low. If TC_CMRx.WAVE = 0, this means that TIOB pin is low. If TC_CMRx.WAVE = 1, this means that TIOB is driven low. 1: TIOB is high. If TC_CMRx.WAVE = 0, this means that TIOB pin is high. If TC_CMRx.WAVE = 1, this means that TIOB is driven high. 790 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.9 TC Interrupt Enable Register Name: TC_IERx [x=0..2] Address: 0x40080024 (0)[0], 0x40080064 (0)[1], 0x400800A4 (0)[2] Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 ETRGS 6 LDRBS 5 LDRAS 4 CPCS 3 CPBS 2 CPAS 1 LOVRS 0 COVFS • COVFS: Counter Overflow 0: No effect. 1: Enables the Counter Overflow Interrupt. • LOVRS: Load Overrun 0: No effect. 1: Enables the Load Overrun Interrupt. • CPAS: RA Compare 0: No effect. 1: Enables the RA Compare Interrupt. • CPBS: RB Compare 0: No effect. 1: Enables the RB Compare Interrupt. • CPCS: RC Compare 0: No effect. 1: Enables the RC Compare Interrupt. • LDRAS: RA Loading 0: No effect. 1: Enables the RA Load Interrupt. • LDRBS: RB Loading 0: No effect. 1: Enables the RB Load Interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 791 • ETRGS: External Trigger 0: No effect. 1: Enables the External Trigger Interrupt. 792 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.10 TC Interrupt Disable Register Name: TC_IDRx [x=0..2] Address: 0x40080028 (0)[0], 0x40080068 (0)[1], 0x400800A8 (0)[2] Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 ETRGS 6 LDRBS 5 LDRAS 4 CPCS 3 CPBS 2 CPAS 1 LOVRS 0 COVFS • COVFS: Counter Overflow 0: No effect. 1: Disables the Counter Overflow Interrupt. • LOVRS: Load Overrun 0: No effect. 1: Disables the Load Overrun Interrupt (if TC_CMRx.WAVE = 0). • CPAS: RA Compare 0: No effect. 1: Disables the RA Compare Interrupt (if TC_CMRx.WAVE = 1). • CPBS: RB Compare 0: No effect. 1: Disables the RB Compare Interrupt (if TC_CMRx.WAVE = 1). • CPCS: RC Compare 0: No effect. 1: Disables the RC Compare Interrupt. • LDRAS: RA Loading 0: No effect. 1: Disables the RA Load Interrupt (if TC_CMRx.WAVE = 0). • LDRBS: RB Loading 0: No effect. 1: Disables the RB Load Interrupt (if TC_CMRx.WAVE = 0). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 793 • ETRGS: External Trigger 0: No effect. 1: Disables the External Trigger Interrupt. 794 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.11 TC Interrupt Mask Register Name: TC_IMRx [x=0..2] Address: 0x4008002C (0)[0], 0x4008006C (0)[1], 0x400800AC (0)[2] Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 ETRGS 6 LDRBS 5 LDRAS 4 CPCS 3 CPBS 2 CPAS 1 LOVRS 0 COVFS • COVFS: Counter Overflow 0: The Counter Overflow Interrupt is disabled. 1: The Counter Overflow Interrupt is enabled. • LOVRS: Load Overrun 0: The Load Overrun Interrupt is disabled. 1: The Load Overrun Interrupt is enabled. • CPAS: RA Compare 0: The RA Compare Interrupt is disabled. 1: The RA Compare Interrupt is enabled. • CPBS: RB Compare 0: The RB Compare Interrupt is disabled. 1: The RB Compare Interrupt is enabled. • CPCS: RC Compare 0: The RC Compare Interrupt is disabled. 1: The RC Compare Interrupt is enabled. • LDRAS: RA Loading 0: The Load RA Interrupt is disabled. 1: The Load RA Interrupt is enabled. • LDRBS: RB Loading 0: The Load RB Interrupt is disabled. 1: The Load RB Interrupt is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 795 • ETRGS: External Trigger 0: The External Trigger Interrupt is disabled. 1: The External Trigger Interrupt is enabled. 796 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.12 TC Block Control Register Name: TC_BCR Address: 0x400800C0 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 SYNC • SYNC: Synchro Command 0: No effect. 1: Asserts the SYNC signal which generates a software trigger simultaneously for each of the channels. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 797 35.7.13 TC Block Mode Register Name: TC_BMR Address: 0x400800C4 Access: Read/Write 31 – 30 – 29 – 28 – 27 – 26 – 25 23 22 21 20 19 – 18 – 17 IDXPHB 16 SWAP 12 EDGPHA 11 QDTRANS 10 SPEEDEN 9 POSEN 8 QDEN 4 3 2 1 0 MAXFILT 15 INVIDX 14 INVB 13 INVA 7 – 6 – 5 TC2XC2S TC1XC1S • TC0XC0S: External Clock Signal 0 Selection Value Name Description 0 TCLK0 Signal connected to XC0: TCLK0 1 – Reserved 2 TIOA1 Signal connected to XC0: TIOA1 3 TIOA2 Signal connected to XC0: TIOA2 • TC1XC1S: External Clock Signal 1 Selection Value Name Description 0 TCLK1 Signal connected to XC1: TCLK1 1 – Reserved 2 TIOA0 Signal connected to XC1: TIOA0 3 TIOA2 Signal connected to XC1: TIOA2 • TC2XC2S: External Clock Signal 2 Selection Value Name Description 0 TCLK2 Signal connected to XC2: TCLK2 1 – Reserved 2 TIOA0 Signal connected to XC2: TIOA0 3 TIOA1 Signal connected to XC2: TIOA1 • QDEN: Quadrature Decoder Enabled 0: Disabled. 1: Enables the QDEC (filter, edge detection and quadrature decoding). Quadrature decoding (direction change) can be disabled using QDTRANS bit. One of the POSEN or SPEEDEN bits must be also enabled. 798 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 24 MAXFILT TC0XC0S • POSEN: Position Enabled 0: Disable position. 1: Enables the position measure on channel 0 and 1. • SPEEDEN: Speed Enabled 0: Disabled. 1: Enables the speed measure on channel 0, the time base being provided by channel 2. • QDTRANS: Quadrature Decoding Transparent 0: Full quadrature decoding logic is active (direction change detected). 1: Quadrature decoding logic is inactive (direction change inactive) but input filtering and edge detection are performed. • EDGPHA: Edge on PHA Count Mode 0: Edges are detected on PHA only. 1: Edges are detected on both PHA and PHB. • INVA: Inverted PHA 0: PHA (TIOA0) is directly driving the QDEC. 1: PHA is inverted before driving the QDEC. • INVB: Inverted PHB 0: PHB (TIOB0) is directly driving the QDEC. 1: PHB is inverted before driving the QDEC. • INVIDX: Inverted Index 0: IDX (TIOA1) is directly driving the QDEC. 1: IDX is inverted before driving the QDEC. • SWAP: Swap PHA and PHB 0: No swap between PHA and PHB. 1: Swap PHA and PHB internally, prior to driving the QDEC. • IDXPHB: Index Pin is PHB Pin 0: IDX pin of the rotary sensor must drive TIOA1. 1: IDX pin of the rotary sensor must drive TIOB0. • MAXFILT: Maximum Filter 1–63: Defines the filtering capabilities. Pulses with a period shorter than MAXFILT+1 peripheral clock cycles are discarded. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 799 35.7.14 TC QDEC Interrupt Enable Register Name: TC_QIER Address: 0x400800C8 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 QERR 1 DIRCHG 0 IDX • IDX: Index 0: No effect. 1: Enables the interrupt when a rising edge occurs on IDX input. • DIRCHG: Direction Change 0: No effect. 1: Enables the interrupt when a change on rotation direction is detected. • QERR: Quadrature Error 0: No effect. 1: Enables the interrupt when a quadrature error occurs on PHA, PHB. 800 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.15 TC QDEC Interrupt Disable Register Name: TC_QIDR Address: 0x400800CC Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 QERR 1 DIRCHG 0 IDX • IDX: Index 0: No effect. 1: Disables the interrupt when a rising edge occurs on IDX input. • DIRCHG: Direction Change 0: No effect. 1: Disables the interrupt when a change on rotation direction is detected. • QERR: Quadrature Error 0: No effect. 1: Disables the interrupt when a quadrature error occurs on PHA, PHB. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 801 35.7.16 TC QDEC Interrupt Mask Register Name: TC_QIMR Address: 0x400800D0 Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 QERR 1 DIRCHG 0 IDX • IDX: Index 0: The interrupt on IDX input is disabled. 1: The interrupt on IDX input is enabled. • DIRCHG: Direction Change 0: The interrupt on rotation direction change is disabled. 1: The interrupt on rotation direction change is enabled. • QERR: Quadrature Error 0: The interrupt on quadrature error is disabled. 1: The interrupt on quadrature error is enabled. 802 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 35.7.17 TC QDEC Interrupt Status Register Name: TC_QISR Address: 0x400800D4 Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 DIR 7 – 6 – 5 – 4 – 3 – 2 QERR 1 DIRCHG 0 IDX • IDX: Index 0: No Index input change since the last read of TC_QISR. 1: The IDX input has changed since the last read of TC_QISR. • DIRCHG: Direction Change 0: No change on rotation direction since the last read of TC_QISR. 1: The rotation direction changed since the last read of TC_QISR. • QERR: Quadrature Error 0: No quadrature error since the last read of TC_QISR. 1: A quadrature error occurred since the last read of TC_QISR. • DIR: Direction Returns an image of the actual rotation direction. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 803 36. High Speed Multimedia Card Interface (HSMCI) 36.1 Description The High Speed Multimedia Card Interface (HSMCI) supports the MultiMedia Card (MMC) Specification V4.3, the SD Memory Card Specification V2.0, the SDIO V2.0 specification and CE-ATA V1.1. The HSMCI includes a command register, response registers, data registers, timeout counters and error detection logic that automatically handle the transmission of commands and, when required, the reception of the associated responses and data with a limited processor overhead. The HSMCI supports stream, block and multi block data read and write, and is compatible with the DMA Controller (DMAC), minimizing processor intervention for large buffer transfers. The HSMCI operates at a rate of up to Master Clock divided by 2 and supports the interfacing of 1 slot(s). Each slot may be used to interface with a High Speed MultiMediaCard bus (up to 30 Cards) or with an SD Memory Card. Only one slot can be selected at a time (slots are multiplexed). A bit field in the SD Card Register performs this selection. The SD Memory Card communication is based on a 9-pin interface (clock, command, four data and three power lines) and the High Speed MultiMedia Card on a 7-pin interface (clock, command, one data, three power lines and one reserved for future use). The SD Memory Card interface also supports High Speed MultiMedia Card operations. The main differences between SD and High Speed MultiMedia Cards are the initialization process and the bus topology. HSMCI fully supports CE-ATA Revision 1.1, built on the MMC System Specification v4.0. The module includes dedicated hardware to issue the command completion signal and capture the host command completion signal disable. 36.2 Embedded Characteristics  Compatible with MultiMedia Card Specification Version 4.3  Compatible with SD Memory Card Specification Version 2.0  Compatible with SDIO Specification Version 2.0  Compatible with CE-ATA Specification 1.1  Cards Clock Rate Up to Master Clock Divided by 2  Boot Operation Mode Support  High Speed Mode Support  Embedded Power Management to Slow Down Clock Rate When Not Used  Supports 1 Multiplexed Slot(s) ̶ Each Slot for either a High Speed MultiMediaCard Bus (Up to 30 Cards) or an SD Memory Card  Support for Stream, Block and Multi-block Data Read and Write  Supports Connection to DMA Controller (DMAC)  Built in FIFO (from 16 to 256 bytes) with Large Memory Aperture Supporting Incremental Access  Support for CE-ATA Completion Signal Disable Command  Protection Against Unexpected Modification On-the-Fly of the Configuration Registers ̶ 804 Minimizes Processor Intervention for Large Buffer Transfers SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 36.3 Block Diagram Figure 36-1. Block Diagram APB Bridge DMAC APB MCCK (1) HSMCI Interface PMC MCK PIO MCCDA (1) MCDA0 (1) MCDA1 (1) MCDA2 (1) MCDA3 (1) Interrupt Control MCDA4 (1) MCDA5 (1) MCDA6 (1) MCDA7 (1) HSMCI Interrupt Note: 1. When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA, MCDAy to HSMCIx_DAy. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 805 36.4 Application Block Diagram Figure 36-2. Application Block Diagram Application Layer ex: File System, Audio, Security, etc. Physical Layer HSMCI Interface 1 2 3 4 5 6 7 1 2 3 4 5 6 78 9 9 1011 1213 8 SDCard MMC 36.5 Pin Name List Table 36-1. I/O Lines Description for 8-bit Configuration (2) Pin Name Pin Description Type(1) Comments MCCDA Command/response I/O/PP/OD CMD of an MMC or SDCard/SDIO MCCK Clock I/O CLK of an MMC or SD Card/SDIO MCDA0 - MCDA7 Data 0..7 of Slot A I/O/PP DAT[0..7] of an MMC DAT[0..3] of an SD Card/SDIO MCDB0 - MCDB7 Data 0..7 of Slot B I/O/PP DAT[0..7] of an MMC DAT[0..3] of an SD Card/SDIO MCDC0 - MCDC7 Data 0..7 of Slot C I/O/PP DAT[0..7] of an MMC DAT[0..3] of an SD Card/SDIO MCDD0 - MCDD7 Data 0..7 of Slot D I/O/PP DAT[0..7] of an MMC DAT[0..3] of an SD Card/SDIO Notes: 806 1. I: Input, O: Output, PP: Push/Pull, OD: Open Drain. 2. When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA, MCCDB to HSMCIx_CDB, MCCDC to HSMCIx_CDC, MCCDD to HSMCIx_CDD, MCDAy to HSMCIx_DAy, MCDBy to HSMCIx_DBy, MCDCy to HSMCIx_DCy, MCDDy to HSMCIx_DDy. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 36.6 Product Dependencies 36.6.1 I/O Lines The pins used for interfacing the High Speed MultiMedia Cards or SD Cards are multiplexed with PIO lines. The programmer must first program the PIO controllers to assign the peripheral functions to HSMCI pins. Table 36-2. 36.6.2 I/O Lines Instance Signal I/O Line Peripheral HSMCI MCCDA PA4 A HSMCI MCCK PA3 A HSMCI MCDA0 PA5 A HSMCI MCDA1 PA6 A HSMCI MCDA2 PA7 A HSMCI MCDA3 PA8 A HSMCI MCDA4 PC28 B HSMCI MCDA5 PC29 B HSMCI MCDA6 PC30 B HSMCI MCDA7 PC31 B Power Management The HSMCI is clocked through the Power Management Controller (PMC), so the programmer must first configure the PMC to enable the HSMCI clock. 36.6.3 Interrupt The HSMCI interface has an interrupt line connected to the Nested Vector Interrupt Controller (NVIC). Handling the HSMCI interrupt requires programming the NVIC before configuring the HSMCI. 36.7 Bus Topology Figure 36-3. High Speed MultiMedia Memory Card Bus Topology 1 2 3 4 5 6 7 9 1011 1213 8 MMC SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 807 The High Speed MultiMedia Card communication is based on a 13-pin serial bus interface. It has three communication lines and four supply lines. Table 36-3. Bus Topology Description HSMCI Pin Name(2) (Slot z) I/O/PP Data MCDz3 CMD I/O/PP/OD Command/response MCCDz 3 VSS1 S Supply voltage ground VSS 4 VDD S Supply voltage VDD 5 CLK I/O Clock MCCK 6 VSS2 S Supply voltage ground VSS 7 DAT[0] I/O/PP Data 0 MCDz0 8 DAT[1] I/O/PP Data 1 MCDz1 9 DAT[2] I/O/PP Data 2 MCDz2 10 DAT[4] I/O/PP Data 4 MCDz4 11 DAT[5] I/O/PP Data 5 MCDz5 12 DAT[6] I/O/PP Data 6 MCDz6 13 DAT[7] I/O/PP Data 7 MCDz7 Pin Number Name Type 1 DAT[3] 2 Notes: 1. 2. Figure 36-4. (1) I: Input, O: Output, PP: Push/Pull, OD: Open Drain. When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA, MCDAy to HSMCIx_DAy. MMC Bus Connections (One Slot) HSMCI MCDA0 MCCDA MCCK 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 2 3 4 5 6 7 9 1011 9 1011 9 1011 1213 8 MMC1 Note: 808 1213 8 MMC2 1213 8 MMC3 When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA MCDAy to HSMCIx_DAy. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 36-5. SD Memory Card Bus Topology 1 2 3 4 5 6 78 9 SD CARD The SD Memory Card bus includes the signals listed in Table 36-4. Table 36-4. SD Memory Card Bus Signals Pin Number Name Type Description HSMCI Pin Name(2) (Slot z) 1 CD/DAT[3] I/O/PP Card detect/ Data line Bit 3 MCDz3 2 CMD PP Command/response MCCDz 3 VSS1 S Supply voltage ground VSS 4 VDD S Supply voltage VDD 5 CLK I/O Clock MCCK 6 VSS2 S Supply voltage ground VSS 7 DAT[0] I/O/PP Data line Bit 0 MCDz0 8 DAT[1] I/O/PP Data line Bit 1 or Interrupt MCDz1 9 DAT[2] I/O/PP Data line Bit 2 MCDz2 1. 2. Figure 36-6. I: input, O: output, PP: Push Pull, OD: Open Drain. When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA, MCDAy to HSMCIx_DAy. SD Card Bus Connections with One Slot MCDA0 - MCDA3 MCCK SD CARD 9 MCCDA 1 2 3 4 5 6 78 Notes: (1) Note: When several HSMCI (x HSMCI) are embedded in a product, MCCK refers to HSMCIx_CK, MCCDA to HSMCIx_CDA MCDAy to HSMCIx_DAy. When the HSMCI is configured to operate with SD memory cards, the width of the data bus can be selected in the HSMCI_SDCR register. Clearing the SDCBUS bit in this register means that the width is one bit; setting it means that the width is four bits. In the case of High Speed MultiMedia cards, only the data line 0 is used. The other data lines can be used as independent PIOs. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 809 36.8 High Speed MultiMediaCard Operations After a power-on reset, the cards are initialized by a special message-based High Speed MultiMediaCard bus protocol. Each message is represented by one of the following tokens:  Command: A command is a token that starts an operation. A command is sent from the host either to a single card (addressed command) or to all connected cards (broadcast command). A command is transferred serially on the CMD line.  Response: A response is a token which is sent from an addressed card or (synchronously) from all connected cards to the host as an answer to a previously received command. A response is transferred serially on the CMD line.  Data: Data can be transferred from the card to the host or vice versa. Data is transferred via the data line. Card addressing is implemented using a session address assigned during the initialization phase by the bus controller to all currently connected cards. Their unique CID number identifies individual cards. The structure of commands, responses and data blocks is described in the High Speed MultiMedia-Card System Specification. See also Table 36-5 on page 811. High Speed MultiMediaCard bus data transfers are composed of these tokens. There are different types of operations. Addressed operations always contain a command and a response token. In addition, some operations have a data token; the others transfer their information directly within the command or response structure. In this case, no data token is present in an operation. The bits on the DAT and the CMD lines are transferred synchronous to the clock HSMCI Clock. Two types of data transfer commands are defined:  Sequential commands: These commands initiate a continuous data stream. They are terminated only when a stop command follows on the CMD line. This mode reduces the command overhead to an absolute minimum.  Block-oriented commands: These commands send a data block succeeded by CRC bits. Both read and write operations allow either single or multiple block transmission. A multiple block transmission is terminated when a stop command follows on the CMD line similarly to the sequential read or when a multiple block transmission has a pre-defined block count (See “Data Transfer Operation” on page 813.). The HSMCI provides a set of registers to perform the entire range of High Speed MultiMedia Card operations. 36.8.1 Command - Response Operation After reset, the HSMCI is disabled and becomes valid after setting the MCIEN bit in the HSMCI_CR Control Register. The PWSEN bit saves power by dividing the HSMCI clock by 2PWSDIV + 1 when the bus is inactive. The two bits, RDPROOF and WRPROOF in the HSMCI Mode Register (HSMCI_MR) allow stopping the HSMCI Clock during read or write access if the internal FIFO is full. This will guarantee data integrity, not bandwidth. All the timings for High Speed MultiMedia Card are defined in the High Speed MultiMediaCard System Specification. The two bus modes (open drain and push/pull) needed to process all the operations are defined in the HSMCI command register. The HSMCI_CMDR allows a command to be carried out. For example, to perform an ALL_SEND_CID command: Host Command CMD 810 S T Content CRC NID Cycles E SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Z ****** CID Z S T Content Z Z Z The command ALL_SEND_CID and the fields and values for the HSMCI_CMDR Control Register are described in Table 36-5 and Table 36-6. Table 36-5. ALL_SEND_CID Command Description CMD Index Type Argument Resp Abbreviation Command Description CMD2 bcr(1) [31:0] stuff bits R2 ALL_SEND_CID Asks all cards to send their CID numbers on the CMD line Note: 1. Table 36-6. bcr means broadcast command with response. Fields and Values for HSMCI_CMDR Command Register Field Value CMDNB (command number) 2 (CMD2) RSPTYP (response type) 2 (R2: 136 bits response) SPCMD (special command) 0 (not a special command) OPCMD (open drain command) 1 MAXLAT (max latency for command to response) 0 (NID cycles ==> 5 cycles) TRCMD (transfer command) 0 (No transfer) TRDIR (transfer direction) X (available only in transfer command) TRTYP (transfer type) X (available only in transfer command) IOSPCMD (SDIO special command) 0 (not a special command) The HSMCI_ARGR contains the argument field of the command. To send a command, the user must perform the following steps:  Fill the argument register (HSMCI_ARGR) with the command argument.  Set the command register (HSMCI_CMDR) (see Table 36-6). The command is sent immediately after writing the command register. While the card maintains a busy indication (at the end of a STOP_TRANSMISSION command CMD12, for example), a new command shall not be sent. The NOTBUSY flag in the status register (HSMCI_SR) is asserted when the card releases the busy indication. If the command requires a response, it can be read in the HSMCI response register (HSMCI_RSPR). The response size can be from 48 bits up to 136 bits depending on the command. The HSMCI embeds an error detection to prevent any corrupted data during the transfer. The following flowchart shows how to send a command to the card and read the response if needed. In this example, the status register bits are polled but setting the appropriate bits in the interrupt enable register (HSMCI_IER) allows using an interrupt method. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 811 Figure 36-7. Command/Response Functional Flow Diagram Set the command argument HSMCI_ARGR = Argument(1) Set the command HSMCI_CMDR = Command Read HSMCI_SR Wait for command ready status flag 0 CMDRDY 1 Check error bits in the status register (1) Yes Status error flags? (1) RETURN ERROR Read response if required Does the command involve a busy indication? No RETURN OK Read HSMCI_SR 0 NOTBUSY 1 RETURN OK Note: 812 1. If the command is SEND_OP_COND, the CRC error flag is always present (refer to R3 response in the High Speed MultiMedia Card specification). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 36.8.2 Data Transfer Operation The High Speed MultiMedia Card allows several read/write operations (single block, multiple blocks, stream, etc.). These kinds of transfer can be selected setting the Transfer Type (TRTYP) field in the HSMCI Command Register (HSMCI_CMDR). These operations can be done using the features of the DMA Controller. In all cases, the block length (BLKLEN field) must be defined either in the mode register HSMCI_MR, or in the Block Register HSMCI_BLKR. This field determines the size of the data block. Consequent to MMC Specification 3.1, two types of multiple block read (or write) transactions are defined (the host can use either one at any time):  Open-ended/Infinite Multiple block read (or write): The number of blocks for the read (or write) multiple block operation is not defined. The card will continuously transfer (or program) data blocks until a stop transmission command is received.  Multiple block read (or write) with pre-defined block count (since version 3.1 and higher): The card will transfer (or program) the requested number of data blocks and terminate the transaction. The stop command is not required at the end of this type of multiple block read (or write), unless terminated with an error. In order to start a multiple block read (or write) with pre-defined block count, the host must correctly program the HSMCI Block Register (HSMCI_BLKR). Otherwise the card will start an open-ended multiple block read. The BCNT field of the Block Register defines the number of blocks to transfer (from 1 to 65535 blocks). Programming the value 0 in the BCNT field corresponds to an infinite block transfer. 36.8.3 Read Operation The following flowchart (Figure 36-8) shows how to read a single block with or without use of DMAC facilities. In this example, a polling method is used to wait for the end of read. Similarly, the user can configure the interrupt enable register (HSMCI_IER) to trigger an interrupt at the end of read. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 813 Figure 36-8. Read Functional Flow Diagram Send SELECT/DESELECT_CARD command(1) to select the card Send SET_BLOCKLEN command(1) No Yes Read with DMAC Reset the DMAEN bit HSMCI_DMA &= ~DMAEN Set the block length (in bytes) HSMCI_MR l= (BlockLength 1 then it is High Bandwidth. Example:    If NB_TRANS = 3, the sequence should be either ̶ MData0 ̶ MData0/Data1 ̶ MData0/Data1/Data2 If NB_TRANS = 2, the sequence should be either ̶ MData0 ̶ MData0/Data1 If NB_TRANS = 1, the sequence should be ̶ Data0 38.6.9.14Isochronous Endpoint Handling: OUT Example The user can ascertain the bank status (free or busy), and the toggle sequencing of the data packet for each bank with the UDPHS_EPTSTAx register in the three bit fields as follows:  TOGGLESQ_STA: PID of the data stored in the current bank  CURRENT_BANK: Number of the bank currently being accessed by the microcontroller.  BUSY_BANK_STA: Number of busy bank This is particularly useful in case of a missing data packet. If the inter-packet delay between the OUT token and the Data is greater than the USB standard, then the ISO-OUT transaction is ignored. (Payload data is not written, no interrupt is generated to the CPU.) If there is a data CRC (Cyclic Redundancy Check) error, the payload is, none the less, written in the endpoint. The ERR_CRISO flag is set in UDPHS_EPTSTAx register. If the endpoint is already full, the packet is not written in the DPRAM. The ERR_FL_ISO flag is set in UDPHS_EPTSTAx. 958 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 If the payload data is greater than the maximum size of the endpoint, then the ERR_OVFLW flag is set. It is the task of the CPU to manage this error. The data packet is written in the endpoint (except the extra data). If the host sends a Zero Length Packet, and the endpoint is free, no data is written in the endpoint, the RX_BK_RDY flag is set, and the BYTE_COUNT field in UDPHS_EPTSTAx register is null. The FRCESTALL command bit is unused for an isochonous endpoint. Otherwise, payload data is written in the endpoint, the RX_BK_RDY interrupt is generated and the BYTE_COUNT in UDPHS_EPTSTAx register is updated. 38.6.9.15STALL STALL is returned by a function in response to an IN token or after the data phase of an OUT or in response to a PING transaction. STALL indicates that a function is unable to transmit or receive data, or that a control pipe request is not supported.  OUT To stall an endpoint, set the FRCESTALL bit in UDPHS_EPTSETSTAx register and after the STALL_SNT flag has been set, set the TOGGLE_SEG bit in the UDPHS_EPTCLRSTAx register.  IN Set the FRCESTALL bit in UDPHS_EPTSETSTAx register. Figure 38-16. Stall Handshake Data OUT Transfer USB Bus Packets Data OUT Token OUT Stall PID FRCESTALL Set by Firmware Cleared by Firmware Interrupt Pending STALL_SNT Set by Hardware Cleared by Firmware Figure 38-17. Stall Handshake Data IN Transfer USB Bus Packets Token IN Stall PID FRCESTALL Cleared by Firmware Set by Firmware Interrupt Pending STALL_SNT Set by Hardware Cleared by Firmware SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 959 38.6.10 Speed Identification The high speed reset is managed by the hardware. At the connection, the host makes a reset which could be a classic reset (full speed) or a high speed reset. At the end of the reset process (full or high), the ENDRESET interrupt is generated. Then the CPU should read the SPEED bit in UDPHS_INTSTAx to ascertain the speed mode of the device. 38.6.11 USB V2.0 High Speed Global Interrupt Interrupts are defined in Section 38.7.3 ”UDPHS Interrupt Enable Register” (UDPHS_IEN) and in Section 38.7.4 ”UDPHS Interrupt Status Register” (UDPHS_INTSTA). 38.6.12 Endpoint Interrupts Interrupts are enabled in UDPHS_IEN (see Section 38.7.3 ”UDPHS Interrupt Enable Register”) and individually masked in UDPHS_EPTCTLENBx (see Section 38.7.12 ”UDPHS Endpoint Control Enable Register”). Table 38-5. 960 Endpoint Interrupt Source Masks SHRT_PCKT Short Packet Interrupt BUSY_BANK Busy Bank Interrupt NAK_OUT NAKOUT Interrupt NAK_IN/ERR_FLUSH NAKIN/Error Flush Interrupt STALL_SNT/ERR_CRISO/ERR_NB_TRA Stall Sent/CRC error/Number of Transaction Error Interrupt RX_SETUP/ERR_FL_ISO Received SETUP/Error Flow Interrupt TX_PK_RD /ERR_TRANS TX Packet Read/Transaction Error Interrupt TX_COMPLT Transmitted IN Data Complete Interrupt RX_BK_RDY Received OUT Data Interrupt ERR_OVFLW Overflow Error Interrupt MDATA_RX MDATA Interrupt DATAX_RX DATAx Interrupt SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 38-18. UDPHS Interrupt Control Interface (UDPHS_IEN) Global IT mask Global IT sources DET_SUSPD MICRO_SOF USB Global IT Sources INT_SOF ENDRESET WAKE_UP ENDOFRSM UPSTR_RES (UDPHS_EPTCTLENBx) SHRT_PCKT EP mask BUSY_BANK EP sources NAK_OUT (UDPHS_IEN) EPT_0 husb2dev interrupt NAK_IN/ERR_FLUSH STALL_SNT/ERR_CRISO/ERR_NBTRA EPT0 IT Sources RX_SETUP/ERR_FL_ISO TX_BK_RDY/ERR_TRANS TX_COMPLT RX_BK_RDY ERR_OVFLW MDATA_RX DATAX_RX (UDPHS_IEN) EPT_x EP mask EP sources (UDPHS_EPTCTLx) INTDIS_DMA EPT1-6 IT Sources disable DMA channelx request (UDPHS_DMACONTROLx) mask (UDPHS_IEN) DMA_x EN_BUFFIT mask DMA CH x END_TR_IT mask DESC_LD_IT SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 961 38.6.13 Power Modes 38.6.13.1Controlling Device States A USB device has several possible states. Refer to Chapter 9 (USB Device Framework) of the Universal Serial Bus Specification, Rev 2.0. Figure 38-19. UDPHS Device State Diagram Attached Hub Reset Hub or Configured Deconfigured Bus Inactive Powered Suspended Bus Activity Power Interruption Reset Bus Inactive Suspended Default Bus Activity Reset Address Assigned Bus Inactive Suspended Address Bus Activity Device Deconfigured Device Configured Bus Inactive Configured Suspended Bus Activity Movement from one state to another depends on the USB bus state or on standard requests sent through control transactions via the default endpoint (endpoint 0). After a period of bus inactivity, the USB device enters Suspend Mode. Accepting Suspend/Resume requests from the USB host is mandatory. Constraints in Suspend Mode are very strict for bus-powered applications; devices may not consume more than 500 µA on the USB bus. While in Suspend Mode, the host may wake up a device by sending a resume signal (bus activity) or a USB device may send a wake-up request to the host, e.g., waking up a PC by moving a USB mouse. The wake-up feature is not mandatory for all devices and must be negotiated with the host. 962 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.6.13.2Not Powered State Self powered devices can detect 5V VBUS using a PIO. When the device is not connected to a host, device power consumption can be reduced by the DETACH bit in UDPHS_CTRL. Disabling the transceiver is automatically done. HSDM, HSDP, FSDP and FSDP lines are tied to GND pull-downs integrated in the hub downstream ports. 38.6.13.3Entering Attached State When no device is connected, the USB FSDP and FSDM signals are tied to GND by 15 KΩ pull-downs integrated in the hub downstream ports. When a device is attached to an hub downstream port, the device connects a 1.5 KΩ pull-up on FSDP. The USB bus line goes into IDLE state, FSDP is pulled-up by the device 1.5 KΩ resistor to 3.3V and FSDM is pulled-down by the 15 KΩ resistor to GND of the host. After pull-up connection, the device enters the powered state. The transceiver remains disabled until bus activity is detected. In case of low power consumption need, the device can be stopped. When the device detects the VBUS, the software must enable the USB transceiver by enabling the EN_UDPHS bit in UDPHS_CTRL register. The software can detach the pull-up by setting DETACH bit in UDPHS_CTRL register. 38.6.13.4From Powered State to Default State (Reset) After its connection to a USB host, the USB device waits for an end-of-bus reset. The unmasked flag ENDRESET is set in the UDPHS_IEN register and an interrupt is triggered. Once the ENDRESET interrupt has been triggered, the device enters Default State. In this state, the UDPHS software must:  Enable the default endpoint, setting the EPT_ENABL flag in the UDPHS_EPTCTLENB[0] register and, optionally, enabling the interrupt for endpoint 0 by writing 1 in EPT_0 of the UDPHS_IEN register. The enumeration then begins by a control transfer.  Configure the Interrupt Mask Register which has been reset by the USB reset detection  Enable the transceiver. In this state, the EN_UDPHS bit in UDPHS_CTRL register must be enabled. 38.6.13.5From Default State to Address State (Address Assigned) After a Set Address standard device request, the USB host peripheral enters the address state. Warning: before the device enters address state, it must achieve the Status IN transaction of the control transfer, i.e., the UDPHS device sets its new address once the TX_COMPLT flag in the UDPHS_EPTCTL[0] register has been received and cleared. To move to address state, the driver software sets the DEV_ADDR field and the FADDR_EN flag in the UDPHS_CTRL register. 38.6.13.6From Address State to Configured State (Device Configured) Once a valid Set Configuration standard request has been received and acknowledged, the device enables endpoints corresponding to the current configuration. This is done by setting the BK_NUMBER, EPT_TYPE, EPT_DIR and EPT_SIZE fields in the UDPHS_EPTCFGx registers and enabling them by setting the EPT_ENABL flag in the UDPHS_EPTCTLENBx registers, and, optionally, enabling corresponding interrupts in the UDPHS_IEN register. 38.6.13.7Entering Suspend State (Bus Activity) When a Suspend (no bus activity on the USB bus) is detected, the DET_SUSPD signal in the UDPHS_STA register is set. This triggers an interrupt if the corresponding bit is set in the UDPHS_IEN register. This flag is cleared by writing to the UDPHS_CLRINT register. Then the device enters Suspend Mode. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 963 In this state bus powered devices must drain less than 500 µA from the 5V VBUS. As an example, the microcontroller switches to slow clock, disables the PLL and main oscillator, and goes into Idle Mode. It may also switch off other devices on the board. The UDPHS device peripheral clocks can be switched off. Resume event is asynchronously detected. 38.6.13.8Receiving a Host Resume In Suspend mode, a resume event on the USB bus line is detected asynchronously, transceiver and clocks disabled (however the pull-up should not be removed). Once the resume is detected on the bus, the signal WAKE_UP in the UDPHS_INTSTA is set. It may generate an interrupt if the corresponding bit in the UDPHS_IEN register is set. This interrupt may be used to wake-up the core, enable PLL and main oscillators and configure clocks. 38.6.13.9Sending an External Resume In Suspend State it is possible to wake-up the host by sending an external resume. The device waits at least 5 ms after being entered in Suspend State before sending an external resume. The device must force a K state from 1 to 15 ms to resume the host. 38.6.14 Test Mode A device must support the TEST_MODE feature when in the Default, Address or Configured High Speed device states. TEST_MODE can be:  Test_J  Test_K  Test_Packet  Test_SEO_NAK (See Section 38.7.7 “UDPHS Test Register” on page 975 for definitions of each test mode.) const char test_packet_buffer[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, // 0xAA,0xAA,0xAA,0xAA,0xAA,0xAA,0xAA,0xAA, // 0xEE,0xEE,0xEE,0xEE,0xEE,0xEE,0xEE,0xEE, // 0xFE,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, // JJJJJJJKKKKKKK * 8 0x7F,0xBF,0xDF,0xEF,0xF7,0xFB,0xFD, // 0xFC,0x7E,0xBF,0xDF,0xEF,0xF7,0xFB,0xFD,0x7E // 10}, JK }; 964 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 JKJKJKJK * 9 JJKKJJKK * 8 JJKKJJKK * 8 JJJJJJJK * 8 {JKKKKKKK * 38.7 USB High Speed Device Port (UDPHS) User Interface Table 38-6. Register Mapping Offset Register Name Access Reset 0x00 UDPHS Control Register UDPHS_CTRL Read-write 0x0000_0200 0x04 UDPHS Frame Number Register UDPHS_FNUM Read-only 0x0000_0000 0x08 - 0x0C Reserved – – – 0x10 UDPHS Interrupt Enable Register UDPHS_IEN Read-write 0x0000_0010 0x14 UDPHS Interrupt Status Register UDPHS_INTSTA Read-only 0x0000_0000 0x18 UDPHS Clear Interrupt Register UDPHS_CLRINT Write-only – 0x1C UDPHS Endpoints Reset Register UDPHS_EPTRST Write-only – 0x20 - 0xCC Reserved – – – 0xE0 UDPHS Test Register UDPHS_TST 0xE4 - 0xE8 Reserved – 0xF0 UDPHS Name1 Register 0xF4 0xF8 Read-write 0x0000_0000 – – UDPHS_IPNAME1 Read-only 0x4855_5342 UDPHS Name2 Register UDPHS_IPNAME2 Read-only 0x3244_4556 UDPHS Features Register UDPHS_IPFEATURES Read-only 0x100 + endpoint * 0x20 + 0x00 UDPHS Endpoint Configuration Register UDPHS_EPTCFG Read-write 0x0000_0000 0x100 + endpoint * 0x20 + 0x04 UDPHS Endpoint Control Enable Register UDPHS_EPTCTLENB Write-only – 0x100 + endpoint * 0x20 + 0x08 UDPHS Endpoint Control Disable Register UDPHS_EPTCTLDIS Write-only – 0x100 + endpoint * 0x20 + 0x0C UDPHS Endpoint Control Register UDPHS_EPTCTL Read-only 0x0000_0000(1) 0x100 + endpoint * 0x20 + 0x10 Reserved (for endpoint) – 0x100 + endpoint * 0x20 + 0x14 UDPHS Endpoint Set Status Register – – UDPHS_EPTSETSTA Write-only – 0x100 + endpoint * 0x20 + 0x18 UDPHS Endpoint Clear Status Register UDPHS_EPTCLRSTA Write-only – 0x100 + endpoint * 0x20 + 0x1C UDPHS Endpoint Status Register UDPHS_EPTSTA Read-only 0x0000_0040 Read-write 0x0000_0000 (2) Registers 0x120 - 0x1DC UDPHS Endpoint1 to 6 0x300 + channel * 0x10 + 0x00 UDPHS DMA Next Descriptor Address Register UDPHS_DMANXTDSC 0x300 + channel * 0x10 + 0x04 UDPHS DMA Channel Address Register UDPHS_DMAADDRESS Read-write 0x0000_0000 0x300 + channel * 0x10 + 0x08 UDPHS DMA Channel Control Register UDPHS_DMACONTROL Read-write 0x0000_0000 0x300 + channel * 0x10 + 0x0C UDPHS DMA Channel Status Register UDPHS_DMASTATUS 0x310 - 0x370 Notes: DMA Channel1 to 5 (3) Read-write 0x0000_0000 Registers 1. The reset value for UDPHS_EPTCTL0 is 0x0000_0001. 2. The addresses for the UDPHS Endpoint registers shown here are for UDPHS Endpoint0. The structure of this group of registers is repeated successively for each endpoint according to the consecution of endpoint registers located between 0x120 and 0x1DC. 3. The DMA channel index refers to the corresponding EP number. When no DMA channel is assigned to one EP, the associated registers are reserved. This is the case for EP0, so DMA Channel 0 registers are reserved. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 965 38.7.1 UDPHS Control Register Name: UDPHS_CTRL Address: 0x400A4000 Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 PULLD_DIS 10 REWAKEUP 9 DETACH 8 EN_UDPHS 7 FADDR_EN 6 5 4 3 DEV_ADDR 2 1 0 • DEV_ADDR: UDPHS Address This field contains the default address (0) after power-up or UDPHS bus reset (read), or it is written with the value set by a SET_ADDRESS request received by the device firmware (write). • FADDR_EN: Function Address Enable 0 = Device is not in address state (read), or only the default function address is used (write). 1 = Device is in address state (read), or this bit is set by the device firmware after a successful status phase of a SET_ADDRESS transaction (write). When set, the only address accepted by the UDPHS controller is the one stored in the UDPHS Address field. It will not be cleared afterwards by the device firmware. It is cleared by hardware on hardware reset, or when UDPHS bus reset is received. • EN_UDPHS: UDPHS Enable 0 = UDPHS is disabled (read), or this bit disables and resets the UDPHS controller (write). Disable the UTMI transceiver. The UTMI may disable the pull-up. 1 = UDPHS is enabled (read), or this bit enables the UDPHS controller (write). • DETACH: Detach Command 0 = UDPHS is attached (read), or this bit pulls up the DP line (attach command) (write). 1 = UDPHS is detached, UTMI transceiver is suspended (read), or this bit simulates a detach on the UDPHS line and forces the UTMI transceiver into suspend state (Suspend M = 0) (write). See PULLD_DIS description below. • REWAKEUP: Send Remote Wake Up 0 = Remote Wake Up is disabled (read), or this bit has no effect (write). 1 = Remote Wake Up is enabled (read), or this bit forces an external interrupt on the UDPHS controller for Remote Wake UP purposes. An Upstream Resume is sent only after the UDPHS bus has been in SUSPEND state for at least 5 ms. This bit is automatically cleared by hardware at the end of the Upstream Resume. 966 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • PULLD_DIS: Pull-Down Disable When set, there is no pull-down on DP & DM. (DM Pull-Down = DP Pull-Down = 0). Note: If the DETACH bit is also set, device DP & DM are left in high impedance state. (See DETACH description above.) DETACH PULLD_DIS DP DM Condition 0 0 Pull up Pull down not recommended 0 1 Pull up High impedance state VBUS present 1 0 Pull down Pull down No VBUS 1 1 High impedance state High impedance state VBUS present & software disconnect SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 967 38.7.2 UDPHS Frame Number Register Name: UDPHS_FNUM Address: 0x400A4004 Access: Read-only 31 FNUM_ERR 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 12 11 10 FRAME_NUMBER 9 8 7 6 5 FRAME_NUMBER 4 3 1 MICRO_FRAME_NUM 0 2 • MICRO_FRAME_NUM: Microframe Number Number of the received microframe (0 to 7) in one frame.This field is reset at the beginning of each new frame (1 ms). One microframe is received each 125 microseconds (1 ms/8). • FRAME_NUMBER: Frame Number as defined in the Packet Field Formats This field is provided in the last received SOF packet (see INT_SOF in the UDPHS Interrupt Status Register). • FNUM_ERR: Frame Number CRC Error This bit is set by hardware when a corrupted Frame Number in Start of Frame packet (or Micro SOF) is received. This bit and the INT_SOF (or MICRO_SOF) interrupt are updated at the same time. 968 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.3 UDPHS Interrupt Enable Register Name: UDPHS_IEN Address: 0x400A4010 Access: Read-write 31 – 30 DMA_6 29 DMA_5 28 DMA_4 27 DMA_3 26 DMA_2 25 DMA_1 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 EPT_6 13 EPT_5 12 EPT_4 11 EPT_3 10 EPT_2 9 EPT_1 8 EPT_0 7 UPSTR_RES 6 ENDOFRSM 5 WAKE_UP 4 ENDRESET 3 INT_SOF 2 MICRO_SOF 1 DET_SUSPD 0 – • DET_SUSPD: Suspend Interrupt Enable 0 = disable Suspend Interrupt. 1 = enable Suspend Interrupt. • MICRO_SOF: Micro-SOF Interrupt Enable 0 = disable Micro-SOF Interrupt. 1 = enable Micro-SOF Interrupt. • INT_SOF: SOF Interrupt Enable 0 = disable SOF Interrupt. 1 = enable SOF Interrupt. • ENDRESET: End Of Reset Interrupt Enable 0 = disable End Of Reset Interrupt. 1 = enable End Of Reset Interrupt. Automatically enabled after USB reset. • WAKE_UP: Wake Up CPU Interrupt Enable 0 = disable Wake Up CPU Interrupt. 1 = enable Wake Up CPU Interrupt. • ENDOFRSM: End Of Resume Interrupt Enable 0 = disable Resume Interrupt. 1 = enable Resume Interrupt. • UPSTR_RES: Upstream Resume Interrupt Enable 0 = disable Upstream Resume Interrupt. 1 = enable Upstream Resume Interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 969 • EPT_x: Endpoint x Interrupt Enable 0 = disable the interrupts for this endpoint. 1 = enable the interrupts for this endpoint. • DMA_x: DMA Channel x Interrupt Enable 0 = disable the interrupts for this channel. 1 = enable the interrupts for this channel. 970 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.4 UDPHS Interrupt Status Register Name: UDPHS_INTSTA Address: 0x400A4014 Access: Read-only 31 – 30 DMA_6 29 DMA_5 28 DMA_4 27 DMA_3 26 DMA_2 25 DMA_1 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 EPT_6 13 EPT_5 12 EPT_4 11 EPT_3 10 EPT_2 9 EPT_1 8 EPT_0 7 UPSTR_RES 6 ENDOFRSM 5 WAKE_UP 4 ENDRESET 3 INT_SOF 2 MICRO_SOF 1 DET_SUSPD 0 SPEED • SPEED: Speed Status 0 = reset by hardware when the hardware is in Full Speed mode. 1 = set by hardware when the hardware is in High Speed mode • DET_SUSPD: Suspend Interrupt 0 = cleared by setting the DET_SUSPD bit in UDPHS_CLRINT register 1 = set by hardware when a UDPHS Suspend (Idle bus for three frame periods, a J state for 3 ms) is detected. This triggers a UDPHS interrupt when the DET_SUSPD bit is set in UDPHS_IEN register. • MICRO_SOF: Micro Start Of Frame Interrupt 0 = cleared by setting the MICRO_SOF bit in UDPHS_CLRINT register. 1 = set by hardware when an UDPHS micro start of frame PID (SOF) has been detected (every 125 us) or synthesized by the macro. This triggers a UDPHS interrupt when the MICRO_SOF bit is set in UDPHS_IEN. In case of detected SOF, the MICRO_FRAME_NUM field in UDPHS_FNUM register is incremented and the FRAME_NUMBER field doesn’t change. Note: The Micro Start Of Frame Interrupt (MICRO_SOF), and the Start Of Frame Interrupt (INT_SOF) are not generated at the same time. • INT_SOF: Start Of Frame Interrupt 0 = cleared by setting the INT_SOF bit in UDPHS_CLRINT. 1 = set by hardware when an UDPHS Start Of Frame PID (SOF) has been detected (every 1 ms) or synthesized by the macro. This triggers a UDPHS interrupt when the INT_SOF bit is set in UDPHS_IEN register. In case of detected SOF, in High Speed mode, the MICRO_FRAME_NUMBER field is cleared in UDPHS_FNUM register and the FRAME_NUMBER field is updated. • ENDRESET: End Of Reset Interrupt 0 = cleared by setting the ENDRESET bit in UDPHS_CLRINT. 1 = set by hardware when an End Of Reset has been detected by the UDPHS controller. This triggers a UDPHS interrupt when the ENDRESET bit is set in UDPHS_IEN. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 971 • WAKE_UP: Wake Up CPU Interrupt 0 = cleared by setting the WAKE_UP bit in UDPHS_CLRINT. 1 = set by hardware when the UDPHS controller is in SUSPEND state and is re-activated by a filtered non-idle signal from the UDPHS line (not by an upstream resume). This triggers a UDPHS interrupt when the WAKE_UP bit is set in UDPHS_IEN register. When receiving this interrupt, the user has to enable the device controller clock prior to operation. Note: this interrupt is generated even if the device controller clock is disabled. • ENDOFRSM: End Of Resume Interrupt 0 = cleared by setting the ENDOFRSM bit in UDPHS_CLRINT. 1 = set by hardware when the UDPHS controller detects a good end of resume signal initiated by the host. This triggers a UDPHS interrupt when the ENDOFRSM bit is set in UDPHS_IEN. • UPSTR_RES: Upstream Resume Interrupt 0 = cleared by setting the UPSTR_RES bit in UDPHS_CLRINT. 1 = set by hardware when the UDPHS controller is sending a resume signal called “upstream resume”. This triggers a UDPHS interrupt when the UPSTR_RES bit is set in UDPHS_IEN. • EPT_x: Endpoint x Interrupt 0 = reset when the UDPHS_EPTSTAx interrupt source is cleared. 1 = set by hardware when an interrupt is triggered by the UDPHS_EPTSTAx register and this endpoint interrupt is enabled by the EPT_x bit in UDPHS_IEN. • DMA_x: DMA Channel x Interrupt 0 = reset when the UDPHS_DMASTATUSx interrupt source is cleared. 1 = set by hardware when an interrupt is triggered by the DMA Channelx and this endpoint interrupt is enabled by the DMA_x bit in UDPHS_IEN. 972 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.5 UDPHS Clear Interrupt Register Name: UDPHS_CLRINT Address: 0x400A4018 Access: Write only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 UPSTR_RES 6 ENDOFRSM 5 WAKE_UP 4 ENDRESET 3 INT_SOF 2 MICRO_SOF 1 DET_SUSPD 0 – • DET_SUSPD: Suspend Interrupt Clear 0 = no effect. 1 = clear the DET_SUSPD bit in UDPHS_INTSTA. • MICRO_SOF: Micro Start Of Frame Interrupt Clear 0 = no effect. 1 = clear the MICRO_SOF bit in UDPHS_INTSTA. • INT_SOF: Start Of Frame Interrupt Clear 0 = no effect. 1 = clear the INT_SOF bit in UDPHS_INTSTA. • ENDRESET: End Of Reset Interrupt Clear 0 = no effect. 1 = clear the ENDRESET bit in UDPHS_INTSTA. • WAKE_UP: Wake Up CPU Interrupt Clear 0 = no effect. 1 = clear the WAKE_UP bit in UDPHS_INTSTA. • ENDOFRSM: End Of Resume Interrupt Clear 0 = no effect. 1 = clear the ENDOFRSM bit in UDPHS_INTSTA. • UPSTR_RES: Upstream Resume Interrupt Clear 0 = no effect. 1 = clear the UPSTR_RES bit in UDPHS_INTSTA. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 973 38.7.6 UDPHS Endpoints Reset Register Name: UDPHS_EPTRST Address: 0x400A401C Access: Write only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 EPT_6 5 EPT_5 4 EPT_4 3 EPT_3 2 EPT_2 1 EPT_1 0 EPT_0 • EPT_x: Endpoint x Reset 0 = no effect. 1 = reset the Endpointx state. Setting this bit clears the Endpoint status UDPHS_EPTSTAx register, except for the TOGGLESQ_STA field. 974 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.7 UDPHS Test Register Name: UDPHS_TST Address: 0x400A40E0 Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 OPMODE2 4 TST_PKT 3 TST_K 2 TST_J 1 0 SPEED_CFG • SPEED_CFG: Speed Configuration Speed Configuration: Value 0 Name Description2 NORMAL Normal Mode: The macro is in Full Speed mode, ready to make a High Speed identification, if the host supports it and then to automatically switch to High Speed mode 1 Reserved 2 HIGH_SPEED Force High Speed: Set this value to force the hardware to work in High Speed mode. Only for debug or test purpose. 3 FULL_SPEED Force Full Speed: Set this value to force the hardware to work only in Full Speed mode. In this configuration, the macro will not respond to a High Speed reset handshake. • TST_J: Test J Mode 0 = no effect. 1 = set to send the J state on the UDPHS line. This enables the testing of the high output drive level on the D+ line. • TST_K: Test K Mode 0 = no effect. 1 = set to send the K state on the UDPHS line. This enables the testing of the high output drive level on the D- line. • TST_PKT: Test Packet Mode 0 = no effect. 1 = set to repetitively transmit the packet stored in the current bank. This enables the testing of rise and fall times, eye patterns, jitter, and any other dynamic waveform specifications. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 975 • OPMODE2: OpMode2 0 = no effect. 1 = set to force the OpMode signal (UTMI interface) to “10”, to disable the bit-stuffing and the NRZI encoding. Note: For the Test mode, Test_SE0_NAK (see Universal Serial Bus Specification, Revision 2.0: 7.1.20, Test Mode Support). Force the device in High Speed mode, and configure a bulk-type endpoint. Do not fill this endpoint for sending NAK to the host. Upon command, a port’s transceiver must enter the High Speed receive mode and remain in that mode until the exit action is taken. This enables the testing of output impedance, low level output voltage and loading characteristics. In addition, while in this mode, upstream facing ports (and only upstream facing ports) must respond to any IN token packet with a NAK handshake (only if the packet CRC is determined to be correct) within the normal allowed device response time. This enables testing of the device squelch level circuitry and, additionally, provides a general purpose stimulus/response test for basic functional testing. 976 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.8 UDPHS Name1 Register Name: UDPHS_IPNAME1 Address: 0x400A40F0 Access: Read-only 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 IP_NAME1 23 22 21 20 IP_NAME1 15 14 13 12 IP_NAME1 7 6 5 4 IP_NAME1 • IP_NAME1 ASCII string “HUSB” SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 977 38.7.9 UDPHS Name2 Register Name: UDPHS_IPNAME2 Address: 0x400A40F4 Access: Read-only 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 IP_NAME2 23 22 21 20 IP_NAME2 15 14 13 12 IP_NAME2 7 6 5 4 IP_NAME2 • IP_NAME2 ASCII string “2DEV” 978 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.10 UDPHS Features Register Name: UDPHS_IPFEATURES Address: 0x400A40F8 Access: Read-only 31 ISO_EPT_15 30 ISO_EPT_14 29 ISO_EPT_13 28 ISO_EPT_12 27 ISO_EPT_11 26 ISO_EPT_10 25 ISO_EPT_9 24 ISO_EPT_8 23 ISO_EPT_7 22 ISO_EPT_6 21 ISO_EPT_5 20 ISO_EPT_4 19 ISO_EPT_3 18 ISO_EPT_2 17 ISO_EPT_1 16 DATAB16_8 15 BW_DPRAM 14 13 FIFO_MAX_SIZE 12 11 10 9 DMA_FIFO_WORD_DEPTH 8 7 DMA_B_SIZ 6 5 DMA_CHANNEL_NBR 4 3 2 1 EPT_NBR_MAX 0 • EPT_NBR_MAX: Max Number of Endpoints Give the max number of endpoints. 0 = if 16 endpoints are hardware implemented. 1 = if 1 endpoint is hardware implemented. 2 = if 2 endpoints are hardware implemented. ... 15 = if 15 endpoints are hardware implemented. • DMA_CHANNEL_NBR: Number of DMA Channels Give the number of DMA channels. 1 = if 1 DMA channel is hardware implemented. 2 = if 2 DMA channels are hardware implemented. ... 7 = if 7 DMA channels are hardware implemented. • DMA_B_SIZ: DMA Buffer Size 0 = if the DMA Buffer size is 16 bits. 1 = if the DMA Buffer size is 24 bits. • DMA_FIFO_WORD_DEPTH: DMA FIFO Depth in Words 0 = if FIFO is 16 words deep. 1 = if FIFO is 1 word deep. 2 = if FIFO is 2 words deep. ... 15 = if FIFO is 15 words deep. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 979 • FIFO_MAX_SIZE: DPRAM Size 0 = if DPRAM is 128 bytes deep. 1 = if DPRAM is 256 bytes deep. 2 = if DPRAM is 512 bytes deep. 3 = if DPRAM is 1024 bytes deep. 4 = if DPRAM is 2048 bytes deep. 5 = if DPRAM is 4096 bytes deep. 6 = if DPRAM is 8192 bytes deep. 7 = if DPRAM is 16384 bytes deep. • BW_DPRAM: DPRAM Byte Write Capability 0 = if DPRAM Write Data Shadow logic is implemented. 1 = if DPRAM is byte write capable. • DATAB16_8: UTMI DataBus16_8 0 = if the UTMI uses an 8-bit parallel data interface (60 MHz, unidirectional). 1 = if the UTMI uses a 16-bit parallel data interface (30 MHz, bidirectional). • ISO_EPT_x: Endpointx High Bandwidth Isochronous Capability 0 = if the endpoint does not have isochronous High Bandwidth Capability. 1 = if the endpoint has isochronous High Bandwidth Capability. 980 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.11 UDPHS Endpoint Configuration Register Name: UDPHS_EPTCFGx [x=0..6] Address: 0x400A4100 [0], 0x400A4120 [1], 0x400A4140 [2], 0x400A4160 [3], 0x400A4180 [4], 0x400A41A0 [5], 0x400A41C0 [6] Access: Read-write 31 EPT_MAPD 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 8 6 5 4 3 EPT_DIR 2 1 EPT_SIZE 7 BK_NUMBER EPT_TYPE NB_TRANS 0 • EPT_SIZE: Endpoint Size Set this field according to the endpoint size in bytes (see Section 38.6.5 ”Endpoint Configuration”). Endpoint Size (1) Value Note: Name Description 0 8 8 bytes 1 16 16 bytes 2 32 32 bytes 3 64 64 bytes 4 128 128 bytes 5 256 256 bytes 6 512 512 bytes 7 1024 1024 bytes 1. 1024 bytes is only for isochronous endpoint. • EPT_DIR: Endpoint Direction 0 = Clear this bit to configure OUT direction for Bulk, Interrupt and Isochronous endpoints. 1 = set this bit to configure IN direction for Bulk, Interrupt and Isochronous endpoints. For Control endpoints this bit has no effect and should be left at zero. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 981 • EPT_TYPE: Endpoint Type Set this field according to the endpoint type (see Section 38.6.5 ”Endpoint Configuration”). (Endpoint 0 should always be configured as control) Endpoint Type Value Name Description 0 CTRL8 Control endpoint 1 ISO Isochronous endpoint 2 BULK Bulk endpoint 3 INT Interrupt endpoint • BK_NUMBER: Number of Banks Set this field according to the endpoint’s number of banks (see Section 38.6.5 ”Endpoint Configuration”). Number of Banks Value Name Description 0 0 Zero bank, the endpoint is not mapped in memory 1 1 One bank (bank 0) 2 2 Double bank (Ping-Pong: bank0/bank1) 3 3 Triple bank (bank0/bank1/bank2) • NB_TRANS: Number Of Transaction per Microframe The Number of transactions per microframe is set by software. Note: Meaningful for high bandwidth isochronous endpoint only. • EPT_MAPD: Endpoint Mapped 0 = the user should reprogram the register with correct values. 1 = set by hardware when the endpoint size (EPT_SIZE) and the number of banks (BK_NUMBER) are correct regarding: – the fifo max capacity (FIFO_MAX_SIZE in UDPHS_IPFEATURES register) – the number of endpoints/banks already allocated – the number of allowed banks for this endpoint 982 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.12 UDPHS Endpoint Control Enable Register Name: UDPHS_EPTCTLENBx [x=0..6] Address: 0x400A4104 [0], 0x400A4124 [1], 0x400A4144 [2], 0x400A4164 [3], 0x400A4184 [4], 0x400A41A4 [5], 0x400A41C4 [6] Access: Write-only 31 SHRT_PCKT 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 BUSY_BANK 17 – 16 – 15 14 12 11 10 9 8 NAK_OUT NAK_IN/ ERR_FLUSH 13 STALL_SNT/ ERR_CRISO/ ERR_NBTRA RX_SETUP/ ERR_FL_ISO TX_PK_RDY/ ERR_TRANS TX_COMPLT RX_BK_RDY ERR_OVFLW 7 MDATA_RX 6 DATAX_RX 4 NYET_DIS 3 INTDIS_DMA 2 – 1 AUTO_VALID 0 EPT_ENABL 5 – For additional Information, see “UDPHS Endpoint Control Register” on page 987. • EPT_ENABL: Endpoint Enable 0 = no effect. 1 = enable endpoint according to the device configuration. • AUTO_VALID: Packet Auto-Valid Enable 0 = no effect. 1 = enable this bit to automatically validate the current packet and switch to the next bank for both IN and OUT transfers. • INTDIS_DMA: Interrupts Disable DMA 0 = no effect. 1 = If set, when an enabled endpoint-originated interrupt is triggered, the DMA request is disabled. • NYET_DIS: NYET Disable (Only for High Speed Bulk OUT endpoints) 0 = no effect. 1 = forces an ACK response to the next High Speed Bulk OUT transfer instead of a NYET response. • DATAX_RX: DATAx Interrupt Enable (Only for high bandwidth Isochronous OUT endpoints) 0 = no effect. 1 = enable DATAx Interrupt. • MDATA_RX: MDATA Interrupt Enable (Only for high bandwidth Isochronous OUT endpoints) 0 = no effect. 1 = enable MDATA Interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 983 • ERR_OVFLW: Overflow Error Interrupt Enable 0 = no effect. 1 = enable Overflow Error Interrupt. • RX_BK_RDY: Received OUT Data Interrupt Enable 0 = no effect. 1 = enable Received OUT Data Interrupt. • TX_COMPLT: Transmitted IN Data Complete Interrupt Enable 0 = no effect. 1 = enable Transmitted IN Data Complete Interrupt. • TX_PK_RDY/ERR_TRANS: TX Packet Ready/Transaction Error Interrupt Enable 0 = no effect. 1 = enable TX Packet Ready/Transaction Error Interrupt. • RX_SETUP/ERR_FL_ISO: Received SETUP/Error Flow Interrupt Enable 0 = no effect. 1 = enable RX_SETUP/Error Flow ISO Interrupt. • STALL_SNT/ERR_CRISO/ERR_NBTRA: Stall Sent /ISO CRC Error/Number of Transaction Error Interrupt Enable 0 = no effect. 1 = enable Stall Sent/Error CRC ISO/Error Number of Transaction Interrupt. • NAK_IN/ERR_FLUSH: NAKIN/Bank Flush Error Interrupt Enable 0 = no effect. 1 = enable NAKIN/Bank Flush Error Interrupt. • NAK_OUT: NAKOUT Interrupt Enable 0 = no effect. 1 = enable NAKOUT Interrupt. • BUSY_BANK: Busy Bank Interrupt Enable 0 = no effect. 1 = enable Busy Bank Interrupt. • SHRT_PCKT: Short Packet Send/Short Packet Interrupt Enable For OUT endpoints: 0 = no effect. 1 = enable Short Packet Interrupt. For IN endpoints: Guarantees short packet at end of DMA Transfer if the UDPHS_DMACONTROLx register END_B_EN and UDPHS_EPTCTLx register AUTOVALID bits are also set. 984 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.13 UDPHS Endpoint Control Disable Register Name: UDPHS_EPTCTLDISx [x=0..6] Address: 0x400A4108 [0], 0x400A4128 [1], 0x400A4148 [2], 0x400A4168 [3], 0x400A4188 [4], 0x400A41A8 [5], 0x400A41C8 [6] Access: Write-only 31 SHRT_PCKT 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 BUSY_BANK 17 – 16 – 15 14 12 11 10 9 8 NAK_OUT NAK_IN/ ERR_FLUSH 13 STALL_SNT/ ERR_CRISO/ ERR_NBTRA RX_SETUP/ ERR_FL_ISO TX_PK_RDY/ ERR_TRANS TX_COMPLT RX_BK_RDY ERR_OVFLW 7 MDATA_RX 6 DATAX_RX 4 NYET_DIS 3 INTDIS_DMA 2 – 1 AUTO_VALID 0 EPT_DISABL 5 – For additional Information, see “UDPHS Endpoint Control Register” on page 987. • EPT_DISABL: Endpoint Disable 0 = no effect. 1 = disable endpoint. • AUTO_VALID: Packet Auto-Valid Disable 0 = no effect. 1 = disable this bit to not automatically validate the current packet. • INTDIS_DMA: Interrupts Disable DMA 0 = no effect. 1 = disable the “Interrupts Disable DMA”. • NYET_DIS: NYET Enable (Only for High Speed Bulk OUT endpoints) 0 = no effect. 1 = let the hardware handle the handshake response for the High Speed Bulk OUT transfer. • DATAX_RX: DATAx Interrupt Disable (Only for High Bandwidth Isochronous OUT endpoints) 0 = no effect. 1 = disable DATAx Interrupt. • MDATA_RX: MDATA Interrupt Disable (Only for High Bandwidth Isochronous OUT endpoints) 0 = no effect. 1 = disable MDATA Interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 985 • ERR_OVFLW: Overflow Error Interrupt Disable 0 = no effect. 1 = disable Overflow Error Interrupt. • RX_BK_RDY: Received OUT Data Interrupt Disable 0 = no effect. 1 = disable Received OUT Data Interrupt. • TX_COMPLT: Transmitted IN Data Complete Interrupt Disable 0 = no effect. 1 = disable Transmitted IN Data Complete Interrupt. • TX_PK_RDY/ERR_TRANS: TX Packet Ready/Transaction Error Interrupt Disable 0 = no effect. 1 = disable TX Packet Ready/Transaction Error Interrupt. • RX_SETUP/ERR_FL_ISO: Received SETUP/Error Flow Interrupt Disable 0 = no effect. 1 = disable RX_SETUP/Error Flow ISO Interrupt. • STALL_SNT/ERR_CRISO/ERR_NBTRA: Stall Sent/ISO CRC Error/Number of Transaction Error Interrupt Disable 0 = no effect. 1 = disable Stall Sent/Error CRC ISO/Error Number of Transaction Interrupt. • NAK_IN/ERR_FLUSH: NAKIN/bank flush error Interrupt Disable 0 = no effect. 1 = disable NAKIN/ Bank Flush Error Interrupt. • NAK_OUT: NAKOUT Interrupt Disable 0 = no effect. 1 = disable NAKOUT Interrupt. • BUSY_BANK: Busy Bank Interrupt Disable 0 = no effect. 1 = disable Busy Bank Interrupt. • SHRT_PCKT: Short Packet Interrupt Disable For OUT endpoints: 0 = no effect. 1 = disable Short Packet Interrupt. For IN endpoints: Never automatically add a zero length packet at end of DMA transfer. 986 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.14 UDPHS Endpoint Control Register Name: UDPHS_EPTCTLx [x=0..6] Address: 0x400A410C [0], 0x400A412C [1], 0x400A414C [2], 0x400A416C [3], 0x400A418C [4], 0x400A41AC [5], 0x400A41CC [6] Access: Read-only 31 SHRT_PCKT 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 BUSY_BANK 17 – 16 – 15 14 12 11 10 9 8 NAK_OUT NAK_IN/ ERR_FLUSH 13 STALL_SNT/ ERR_CRISO/ ERR_NBTRA RX_SETUP/ ERR_FL_ISO TX_PK_RDY/ ERR_TRANS TX_COMPLT RX_BK_RDY ERR_OVFLW 7 MDATA_RX 6 DATAX_RX 4 NYET_DIS 3 INTDIS_DMA 2 – 1 AUTO_VALID 0 EPT_ENABL 5 – • EPT_ENABL: Endpoint Enable 0 = If cleared, the endpoint is disabled according to the device configuration. Endpoint 0 should always be enabled after a hardware or UDPHS bus reset and participate in the device configuration. 1 = If set, the endpoint is enabled according to the device configuration. • AUTO_VALID: Packet Auto-Valid Enabled (Not for CONTROL Endpoints) Set this bit to automatically validate the current packet and switch to the next bank for both IN and OUT endpoints. For IN Transfer: If this bit is set, then the UDPHS_EPTSTAx register TX_PK_RDY bit is set automatically when the current bank is full and at the end of DMA buffer if the UDPHS_DMACONTROLx register END_B_EN bit is set. The user may still set the UDPHS_EPTSTAx register TX_PK_RDY bit if the current bank is not full, unless the user wants to send a Zero Length Packet by software. For OUT Transfer: If this bit is set, then the UDPHS_EPTSTAx register RX_BK_RDY bit is automatically reset for the current bank when the last packet byte has been read from the bank FIFO or at the end of DMA buffer if the UDPHS_DMACONTROLx register END_B_EN bit is set. For example, to truncate a padded data packet when the actual data transfer size is reached. The user may still clear the UDPHS_EPTSTAx register RX_BK_RDY bit, for example, after completing a DMA buffer by software if UDPHS_DMACONTROLx register END_B_EN bit was disabled or in order to cancel the read of the remaining data bank(s). • INTDIS_DMA: Interrupt Disables DMA If set, when an enabled endpoint-originated interrupt is triggered, the DMA request is disabled regardless of the UDPHS_IEN register EPT_x bit for this endpoint. Then, the firmware will have to clear or disable the interrupt source or clear this bit if transfer completion is needed. If the exception raised is associated with the new system bank packet, then the previous DMA packet transfer is normally completed, but the new DMA packet transfer is not started (not requested). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 987 If the exception raised is not associated to a new system bank packet (NAK_IN, NAK_OUT, ERR_FL_ISO...), then the request cancellation may happen at any time and may immediately stop the current DMA transfer. This may be used, for example, to identify or prevent an erroneous packet to be transferred into a buffer or to complete a DMA buffer by software after reception of a short packet, or to perform buffer truncation on ERR_FL_ISO interrupt for adaptive rate. • NYET_DIS: NYET Disable (Only for High Speed Bulk OUT endpoints) 0 = If clear, this bit lets the hardware handle the handshake response for the High Speed Bulk OUT transfer. 1 = If set, this bit forces an ACK response to the next High Speed Bulk OUT transfer instead of a NYET response. Note: According to the Universal Serial Bus Specification, Rev 2.0 (8.5.1.1 NAK Responses to OUT/DATA During PING Protocol), a NAK response to an HS Bulk OUT transfer is expected to be an unusual occurrence. • DATAX_RX: DATAx Interrupt Enabled (Only for High Bandwidth Isochronous OUT endpoints) 0 = no effect. 1 = send an interrupt when a DATA2, DATA1 or DATA0 packet has been received meaning the whole microframe data payload has been received. • MDATA_RX: MDATA Interrupt Enabled (Only for High Bandwidth Isochronous OUT endpoints) 0 = no effect. 1 = send an interrupt when an MDATA packet has been received and so at least one packet of the microframe data payload has been received. • ERR_OVFLW: Overflow Error Interrupt Enabled 0 = Overflow Error Interrupt is masked. 1 = Overflow Error Interrupt is enabled. • RX_BK_RDY: Received OUT Data Interrupt Enabled 0 = Received OUT Data Interrupt is masked. 1 = Received OUT Data Interrupt is enabled. • TX_COMPLT: Transmitted IN Data Complete Interrupt Enabled 0 = Transmitted IN Data Complete Interrupt is masked. 1 = Transmitted IN Data Complete Interrupt is enabled. • TX_PK_RDY/ERR_TRANS: TX Packet Ready/Transaction Error Interrupt Enabled 0 = TX Packet Ready/Transaction Error Interrupt is masked. 1 = TX Packet Ready/Transaction Error Interrupt is enabled. Caution: Interrupt source is active as long as the corresponding UDPHS_EPTSTAx register TX_PK_RDY flag remains low. If there are no more banks available for transmitting after the software has set UDPHS_EPTSTAx/TX_PK_RDY for the last transmit packet, then the interrupt source remains inactive until the first bank becomes free again to transmit at UDPHS_EPTSTAx/TX_PK_RDY hardware clear. 988 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • RX_SETUP/ERR_FL_ISO: Received SETUP/Error Flow Interrupt Enabled 0 = Received SETUP/Error Flow Interrupt is masked. 1 = Received SETUP/Error Flow Interrupt is enabled. • STALL_SNT/ERR_CRISO/ERR_NBTRA: Stall Sent/ISO CRC Error/Number of Transaction Error Interrupt Enabled 0 = Stall Sent/ISO CRC error/number of Transaction Error Interrupt is masked. 1 = Stall Sent /ISO CRC error/number of Transaction Error Interrupt is enabled. • NAK_IN/ERR_FLUSH: NAKIN/Bank Flush Error Interrupt Enabled 0 = NAKIN Interrupt is masked. 1 = NAKIN/Bank Flush Error Interrupt is enabled. • NAK_OUT: NAKOUT Interrupt Enabled 0 = NAKOUT Interrupt is masked. 1 = NAKOUT Interrupt is enabled. • BUSY_BANK: Busy Bank Interrupt Enabled 0 = BUSY_BANK Interrupt is masked. 1 = BUSY_BANK Interrupt is enabled. For OUT endpoints: an interrupt is sent when all banks are busy. For IN endpoints: an interrupt is sent when all banks are free. • SHRT_PCKT: Short Packet Interrupt Enabled For OUT endpoints: send an Interrupt when a Short Packet has been received. 0 = Short Packet Interrupt is masked. 1 = Short Packet Interrupt is enabled. For IN endpoints: a Short Packet transmission is guaranteed upon end of the DMA Transfer, thus signaling a BULK or INTERRUPT end of transfer or an end of isochronous (micro-)frame data, but only if the UDPHS_DMACONTROLx register END_B_EN and UDPHS_EPTCTLx register AUTO_VALID bits are also set. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 989 38.7.15 UDPHS Endpoint Set Status Register Name: UDPHS_EPTSETSTAx [x=0..6] Address: 0x400A4114 [0], 0x400A4134 [1], 0x400A4154 [2], 0x400A4174 [3], 0x400A4194 [4], 0x400A41B4 [5], 0x400A41D4 [6] Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 TX_PK_RDY 10 – 9 KILL_BANK 8 – 7 – 6 – 5 FRCESTALL 4 – 3 – 2 – 1 – 0 – • FRCESTALL: Stall Handshake Request Set 0 = no effect. 1 = set this bit to request a STALL answer to the host for the next handshake Refer to chapters 8.4.5 (Handshake Packets) and 9.4.5 (Get Status) of the Universal Serial Bus Specification, Rev 2.0 for more information on the STALL handshake. • KILL_BANK: KILL Bank Set (for IN Endpoint) 0 = no effect. 1 = kill the last written bank. • TX_PK_RDY: TX Packet Ready Set 0 = no effect. 1 = set this bit after a packet has been written into the endpoint FIFO for IN data transfers – This flag is used to generate a Data IN transaction (device to host). – Device firmware checks that it can write a data payload in the FIFO, checking that TX_PK_RDY is cleared. – Transfer to the FIFO is done by writing in the “Buffer Address” register. – Once the data payload has been transferred to the FIFO, the firmware notifies the UDPHS device setting TX_PK_RDY to one. – UDPHS bus transactions can start. – TXCOMP is set once the data payload has been received by the host. – Data should be written into the endpoint FIFO only after this bit has been cleared. – Set this bit without writing data to the endpoint FIFO to send a Zero Length Packet. 990 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.16 UDPHS Endpoint Clear Status Register Name: UDPHS_EPTCLRSTAx [x=0..6] Address: 0x400A4118 [0], 0x400A4138 [1], 0x400A4158 [2], 0x400A4178 [3], 0x400A4198 [4], 0x400A41B8 [5], 0x400A41D8 [6] Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 14 NAK_IN/ ERR_FLUSH 13 STALL_SNT/ ERR_NBTRA 12 RX_SETUP/ ERR_FL_ISO 11 10 9 8 – TX_COMPLT RX_BK_RDY – 6 TOGGLESQ 5 FRCESTALL 4 – 3 – 2 – 1 – 0 – NAK_OUT 7 – • FRCESTALL: Stall Handshake Request Clear 0 = no effect. 1 = clear the STALL request. The next packets from host will not be STALLed. • TOGGLESQ: Data Toggle Clear 0 = no effect. 1 = clear the PID data of the current bank For OUT endpoints, the next received packet should be a DATA0. For IN endpoints, the next packet will be sent with a DATA0 PID. • RX_BK_RDY: Received OUT Data Clear 0 = no effect. 1 = clear the RX_BK_RDY flag of UDPHS_EPTSTAx. • TX_COMPLT: Transmitted IN Data Complete Clear 0 = no effect. 1 = clear the TX_COMPLT flag of UDPHS_EPTSTAx. • RX_SETUP/ERR_FL_ISO: Received SETUP/Error Flow Clear 0 = no effect. 1 = clear the RX_SETUP/ERR_FL_ISO flags of UDPHS_EPTSTAx. • STALL_SNT/ERR_NBTRA: Stall Sent/Number of Transaction Error Clear 0 = no effect. 1 = clear the STALL_SNT/ERR_NBTRA flags of UDPHS_EPTSTAx. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 991 • NAK_IN/ERR_FLUSH: NAKIN/Bank Flush Error Clear 0 = no effect. 1 = clear the NAK_IN/ERR_FLUSH flags of UDPHS_EPTSTAx. • NAK_OUT: NAKOUT Clear 0 = no effect. 1 = clear the NAK_OUT flag of UDPHS_EPTSTAx. 992 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.17 UDPHS Endpoint Status Register Name: UDPHS_EPTSTAx [x=0..6] Address: 0x400A411C [0], 0x400A413C [1], 0x400A415C [2], 0x400A417C [3], 0x400A419C [4], 0x400A41BC [5], 0x400A41DC [6] Access: Read-only 31 SHRT_PCKT 30 29 28 27 BYTE_COUNT 26 25 23 22 21 20 19 18 17 16 CURRENT_BANK/ CONTROL_DIR BYTE_COUNT 15 14 NAK_OUT NAK_IN/ ERR_FLUSH 7 6 TOGGLESQ_STA 13 STALL_SNT/ ERR_CRISO/ ERR_NBTRA BUSY_BANK_STA 24 12 11 10 9 8 RX_SETUP/ ERR_FL_ISO TX_PK_RDY/ ERR_TRANS TX_COMPLT RX_BK_RDY/ KILL_BANK ERR_OVFLW 4 – 3 – 2 – 1 – 0 – 5 FRCESTALL • FRCESTALL: Stall Handshake Request 0 = no effect. 1= If set a STALL answer will be done to the host for the next handshake. This bit is reset by hardware upon received SETUP. • TOGGLESQ_STA: Toggle Sequencing Toggle Sequencing: – IN endpoint: it indicates the PID Data Toggle that will be used for the next packet sent. This is not relative to the current bank. – CONTROL and OUT endpoint: These bits are set by hardware to indicate the PID data of the current bank: Value Name Description 0 DATA0 DATA0 1 DATA1 DATA1 2 DATA2 Data2 (only for High Bandwidth Isochronous Endpoint) 3 MDATA MData (only for High Bandwidth Isochronous Endpoint) Notes: 1. In OUT transfer, the Toggle information is meaningful only when the current bank is busy (Received OUT Data = 1). 2. These bits are updated for OUT transfer: - a new data has been written into the current bank. - the user has just cleared the Received OUT Data bit to switch to the next bank. 3. For High Bandwidth Isochronous Out endpoint, it is recommended to check the UDPHS_EPTSTAx/ERR_TRANS bit to know if the toggle sequencing is correct or not. 4. This field is reset to DATA1 by the UDPHS_EPTCLRSTAx register TOGGLESQ bit, and by UDPHS_EPTCTLDISx (disable endpoint). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 993 • ERR_OVFLW: Overflow Error This bit is set by hardware when a new too-long packet is received. Example: If the user programs an endpoint 64 bytes wide and the host sends 128 bytes in an OUT transfer, then the Overflow Error bit is set. This bit is updated at the same time as the BYTE_COUNT field. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by UDPHS_EPTCTLDISx (disable endpoint). • RX_BK_RDY/KILL_BANK: Received OUT Data/KILL Bank – Received OUT Data: (For OUT endpoint or Control endpoint) This bit is set by hardware after a new packet has been stored in the endpoint FIFO. This bit is cleared by the device firmware after reading the OUT data from the endpoint. For multi-bank endpoints, this bit may remain active even when cleared by the device firmware, this if an other packet has been received meanwhile. Hardware assertion of this bit may generate an interrupt if enabled by the UDPHS_EPTCTLx register RX_BK_RDY bit. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by UDPHS_EPTCTLDISx (disable endpoint). – KILL Bank: (For IN endpoint) – the bank is really cleared or the bank is sent, BUSY_BANK_STA is decremented. – the bank is not cleared but sent on the IN transfer, TX_COMPLT – the bank is not cleared because it was empty. The user should wait that this bit is cleared before trying to clear another packet. Note: “Kill a packet” may be refused if at the same time, an IN token is coming and the current packet is sent on the UDPHS line. In this case, the TX_COMPLT bit is set. Take notice however, that if at least two banks are ready to be sent, there is no problem to kill a packet even if an IN token is coming. In fact, in that case, the current bank is sent (IN transfer) and the last bank is killed. • TX_COMPLT: Transmitted IN Data Complete This bit is set by hardware after an IN packet has been transmitted for isochronous endpoints and after it has been accepted (ACK’ed) by the host for Control, Bulk and Interrupt endpoints. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint), and by UDPHS_EPTCTLDISx (disable endpoint). • TX_PK_RDY/ERR_TRANS: TX Packet Ready/Transaction Error – TX Packet Ready: This bit is cleared by hardware, as soon as the packet has been sent for isochronous endpoints, or after the host has acknowledged the packet for Control, Bulk and Interrupt endpoints. For Multi-bank endpoints, this bit may remain clear even after software is set if another bank is available to transmit. Hardware clear of this bit may generate an interrupt if enabled by the UDPHS_EPTCTLx register TX_PK_RDY bit. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint), and by UDPHS_EPTCTLDISx (disable endpoint). – Transaction Error: (For high bandwidth isochronous OUT endpoints) (Read-Only) This bit is set by hardware when a transaction error occurs inside one microframe. If one toggle sequencing problem occurs among the n-transactions (n = 1, 2 or 3) inside a microframe, then this bit is still set as long as the current bank contains one “bad” n-transaction. (see “CURRENT_BANK/CONTROL_DIR: Current Bank/Control Direction” on page 996) As soon as the current bank is relative to a new “good” n-transactions, then this bit is reset. Notes: 994 1. A transaction error occurs when the toggle sequencing does not respect the Universal Serial Bus Specification, Rev 2.0 (5.9.2 High Bandwidth Isochronous endpoints) (Bad PID, missing data....) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 2. When a transaction error occurs, the user may empty all the “bad” transactions by clearing the Received OUT Data flag (RX_BK_RDY). If this bit is reset, then the user should consider that a new n-transaction is coming. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint), and by UDPHS_EPTCTLDISx (disable endpoint). • RX_SETUP/ERR_FL_ISO: Received SETUP/Error Flow – Received SETUP: (for Control endpoint only) This bit is set by hardware when a valid SETUP packet has been received from the host. It is cleared by the device firmware after reading the SETUP data from the endpoint FIFO. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint), and by UDPHS_EPTCTLDISx (disable endpoint). – Error Flow: (for isochronous endpoint only) This bit is set by hardware when a transaction error occurs. – Isochronous IN transaction is missed, the micro has no time to fill the endpoint (underflow). – Isochronous OUT data is dropped because the bank is busy (overflow). This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by UDPHS_EPTCTLDISx (disable endpoint). • STALL_SNT/ERR_CRISO/ERR_NBTRA: Stall Sent/CRC ISO Error/Number of Transaction Error – STALL_SNT: (for Control, Bulk and Interrupt endpoints) This bit is set by hardware after a STALL handshake has been sent as requested by the UDPHS_EPTSTAx register FRCESTALL bit. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by UDPHS_EPTCTLDISx (disable endpoint). – ERR_CRISO: (for Isochronous OUT endpoints) (Read-only) This bit is set by hardware if the last received data is corrupted (CRC error on data). This bit is updated by hardware when new data is received (Received OUT Data bit). – ERR_NBTRA: (for High Bandwidth Isochronous IN endpoints) This bit is set at the end of a microframe in which at least one data bank has been transmitted, if less than the number of transactions per micro-frame banks (UDPHS_EPTCFGx register NB_TRANS) have been validated for transmission inside this microframe. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by UDPHS_EPTCTLDISx (disable endpoint). • NAK_IN/ERR_FLUSH: NAK IN/Bank Flush Error – NAK_IN: This bit is set by hardware when a NAK handshake has been sent in response to an IN request from the Host. This bit is cleared by software. – ERR_FLUSH: (for High Bandwidth Isochronous IN endpoints) This bit is set when flushing unsent banks at the end of a microframe. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by EPT_CTL_DISx (disable endpoint). • NAK_OUT: NAK OUT This bit is set by hardware when a NAK handshake has been sent in response to an OUT or PING request from the Host. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by EPT_CTL_DISx (disable endpoint). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 995 • CURRENT_BANK/CONTROL_DIR: Current Bank/Control Direction – Current Bank: (all endpoints except Control endpoint) These bits are set by hardware to indicate the number of the current bank. Value Name Description 0 BANK0 Bank 0 (or single bank) 1 BANK1 Bank 1 2 BANK2 Bank 2 Note: The current bank is updated each time the user: - Sets the TX Packet Ready bit to prepare the next IN transfer and to switch to the next bank. - Clears the received OUT data bit to access the next bank. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by UDPHS_EPTCTLDISx (disable endpoint). – Control Direction: (for Control endpoint only) 0 = a Control Write is requested by the Host. 1 = a Control Read is requested by the Host. Notes: 1. This bit corresponds with the 7th bit of the bmRequestType (Byte 0 of the Setup Data). 2. This bit is updated after receiving new setup data. • BUSY_BANK_STA: Busy Bank Number These bits are set by hardware to indicate the number of busy banks. IN endpoint: it indicates the number of busy banks filled by the user, ready for IN transfer. OUT endpoint: it indicates the number of busy banks filled by OUT transaction from the Host. Value Name Description 0 1BUSYBANK 1 busy bank 1 2BUSYBANKS 2 busy banks 2 3BUSYBANKS 3 busy banks • BYTE_COUNT: UDPHS Byte Count Byte count of a received data packet. This field is incremented after each write into the endpoint (to prepare an IN transfer). This field is decremented after each reading into the endpoint (OUT transfer). This field is also updated at RX_BK_RDY flag clear with the next bank. This field is also updated at TX_PK_RDY flag set with the next bank. This field is reset by EPT_x of UDPHS_EPTRST register. • SHRT_PCKT: Short Packet An OUT Short Packet is detected when the receive byte count is less than the configured UDPHS_EPTCFGx register EPT_Size. This bit is updated at the same time as the BYTE_COUNT field. This bit is reset by UDPHS_EPTRST register EPT_x (reset endpoint) and by UDPHS_EPTCTLDISx (disable endpoint). 996 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.18 UDPHS DMA Channel Transfer Descriptor The DMA channel transfer descriptor is loaded from the memory. Be careful with the alignment of this buffer. The structure of the DMA channel transfer descriptor is defined by three parameters as described below: Offset 0: The address must be aligned: 0xXXXX0 Next Descriptor Address Register: UDPHS_DMANXTDSCx Offset 4: The address must be aligned: 0xXXXX4 DMA Channelx Address Register: UDPHS_DMAADDRESSx Offset 8: The address must be aligned: 0xXXXX8 DMA Channelx Control Register: UDPHS_DMACONTROLx To use the DMA channel transfer descriptor, fill the structures with the correct value (as described in the following pages). Then write directly in UDPHS_DMANXTDSCx the address of the descriptor to be used first. Then write 1 in the LDNXT_DSC bit of UDPHS_DMACONTROLx (load next channel transfer descriptor). The descriptor is automatically loaded upon Endpointx request for packet transfer. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 997 38.7.19 UDPHS DMA Next Descriptor Address Register Name: UDPHS_DMANXTDSCx [x = 0..5] Address: 0x400A4300 [0], 0x400A4310 [1], 0x400A4320 [2], 0x400A4330 [3], 0x400A4340 [4], 0x400A4350 [5] Access: Read-write 31 30 29 28 27 NXT_DSC_ADD 26 25 24 23 22 21 20 19 NXT_DSC_ADD 18 17 16 15 14 13 12 11 NXT_DSC_ADD 10 9 8 7 6 5 4 3 NXT_DSC_ADD 2 1 0 Note: Channel 0 is not used. • NXT_DSC_ADD This field points to the next channel descriptor to be processed. This channel descriptor must be aligned, so bits 0 to 3 of the address must be equal to zero. 998 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 38.7.20 UDPHS DMA Channel Address Register Name: UDPHS_DMAADDRESSx [x = 0..5] Address: 0x400A4304 [0], 0x400A4314 [1], 0x400A4324 [2], 0x400A4334 [3], 0x400A4344 [4], 0x400A4354 [5] Access: Read-write 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 BUFF_ADD 23 22 21 20 BUFF_ADD 15 14 13 12 BUFF_ADD 7 6 5 4 BUFF_ADD Note: Channel 0 is not used. • BUFF_ADD This field determines the AHB bus starting address of a DMA channel transfer. Channel start and end addresses may be aligned on any byte boundary. The firmware may write this field only when the UDPHS_DMASTATUS register CHANN_ENB bit is clear. This field is updated at the end of the address phase of the current access to the AHB bus. It is incrementing of the access byte width. The access width is 4 bytes (or less) at packet start or end, if the start or end address is not aligned on a word boundary. The packet start address is either the channel start address or the next channel address to be accessed in the channel buffer. The packet end address is either the channel end address or the latest channel address accessed in the channel buffer. The channel start address is written by software or loaded from the descriptor, whereas the channel end address is either determined by the end of buffer or the UDPHS device, USB end of transfer if the UDPHS_DMACONTROLx register END_TR_EN bit is set. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 999 38.7.21 UDPHS DMA Channel Control Register Name: UDPHS_DMACONTROLx [x = 0..5] Address: 0x400A4308 [0], 0x400A4318 [1], 0x400A4328 [2], 0x400A4338 [3], 0x400A4348 [4], 0x400A4358 [5] Access: Read-write 31 30 29 28 27 BUFF_LENGTH 26 25 24 23 22 21 20 19 BUFF_LENGTH 18 17 16 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 BURST_LCK 6 DESC_LD_IT 5 END_BUFFIT 4 END_TR_IT 3 END_B_EN 2 END_TR_EN 1 LDNXT_DSC 0 CHANN_ENB Note: Channel 0 is not used. • CHANN_ENB (Channel Enable Command) 0 = DMA channel is disabled at and no transfer will occur upon request. This bit is also cleared by hardware when the channel source bus is disabled at end of buffer. If the UDPHS_DMACONTROL register LDNXT_DSC bit has been cleared by descriptor loading, the firmware will have to set the corresponding CHANN_ENB bit to start the described transfer, if needed. If the UDPHS_DMACONTROL register LDNXT_DSC bit is cleared, the channel is frozen and the channel registers may then be read and/or written reliably as soon as both UDPHS_DMASTATUS register CHANN_ENB and CHANN_ACT flags read as 0. If a channel request is currently serviced when this bit is cleared, the DMA FIFO buffer is drained until it is empty, then the UDPHS_DMASTATUS register CHANN_ENB bit is cleared. If the LDNXT_DSC bit is set at or after this bit clearing, then the currently loaded descriptor is skipped (no data transfer occurs) and the next descriptor is immediately loaded. 1 = UDPHS_DMASTATUS register CHANN_ENB bit will be set, thus enabling DMA channel data transfer. Then any pending request will start the transfer. This may be used to start or resume any requested transfer. • LDNXT_DSC: Load Next Channel Transfer Descriptor Enable (Command) 0 = no channel register is loaded after the end of the channel transfer. 1 = the channel controller loads the next descriptor after the end of the current transfer, i.e. when the UDPHS_DMASTATUS/CHANN_ENB bit is reset. If the UDPHS_DMA CONTROL/CHANN_ENB bit is cleared, the next descriptor is immediately loaded upon transfer request. DMA Channel Control Command Summary LDNXT_DSC CHANN_ENB 0 0 Stop now 0 1 Run and stop at end of buffer 1 0 Load next descriptor now 1 1 Run and link at end of buffer 1000 Description SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • END_TR_EN: End of Transfer Enable (Control) Used for OUT transfers only. 0 = USB end of transfer is ignored. 1 = UDPHS device can put an end to the current buffer transfer. When set, a BULK or INTERRUPT short packet or the last packet of an ISOCHRONOUS (micro) frame (DATAX) will close the current buffer and the UDPHS_DMASTATUSx register END_TR_ST flag will be raised. This is intended for UDPHS non-prenegotiated end of transfer (BULK or INTERRUPT) or ISOCHRONOUS microframe data buffer closure. • END_B_EN: End of Buffer Enable (Control) 0 = DMA Buffer End has no impact on USB packet transfer. 1 = endpoint can validate the packet (according to the values programmed in the UDPHS_EPTCTLx register AUTO_VALID and SHRT_PCKT fields) at DMA Buffer End, i.e. when the UDPHS_DMASTATUS register BUFF_COUNT reaches 0. This is mainly for short packet IN validation initiated by the DMA reaching end of buffer, but could be used for OUT packet truncation (discarding of unwanted packet data) at the end of DMA buffer. • END_TR_IT: End of Transfer Interrupt Enable 0 = UDPHS device initiated buffer transfer completion will not trigger any interrupt at UDPHS_STATUSx/END_TR_ST rising. 1 = an interrupt is sent after the buffer transfer is complete, if the UDPHS device has ended the buffer transfer. Use when the receive size is unknown. • END_BUFFIT: End of Buffer Interrupt Enable 0 = UDPHS_DMA_STATUSx/END_BF_ST rising will not trigger any interrupt. 1 = an interrupt is generated when the UDPHS_DMASTATUSx register BUFF_COUNT reaches zero. • DESC_LD_IT: Descriptor Loaded Interrupt Enable 0 = UDPHS_DMASTATUSx/DESC_LDST rising will not trigger any interrupt. 1 = an interrupt is generated when a descriptor has been loaded from the bus. • BURST_LCK: Burst Lock Enable 0 = the DMA never locks bus access. 1 = USB packets AHB data bursts are locked for maximum optimization of the bus bandwidth usage and maximization of fly-by AHB burst duration. • BUFF_LENGTH: Buffer Byte Length (Write-only) This field determines the number of bytes to be transferred until end of buffer. The maximum channel transfer size (64 KBytes) is reached when this field is 0 (default value). If the transfer size is unknown, this field should be set to 0, but the transfer end may occur earlier under UDPHS device control. When this field is written, The UDPHS_DMASTATUSx register BUFF_COUNT field is updated with the write value. Notes: 1. Bits [31:2] are only writable when issuing a channel Control Command other than “Stop Now”. 2. For reliability it is highly recommended to wait for both UDPHS_DMASTATUSx register CHAN_ACT and CHAN_ENB flags are at 0, thus ensuring the channel has been stopped before issuing a command other than “Stop Now”. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1001 38.7.22 UDPHS DMA Channel Status Register Name: UDPHS_DMASTATUSx [x = 0..5] Address: 0x400A430C [0], 0x400A431C [1], 0x400A432C [2], 0x400A433C [3], 0x400A434C [4], 0x400A435C [5] Access: Read-write 31 30 29 28 27 BUFF_COUNT 26 25 24 23 22 21 20 19 BUFF_COUNT 18 17 16 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 DESC_LDST 5 END_BF_ST 4 END_TR_ST 3 – 2 – 1 CHANN_ACT 0 CHANN_ENB Note: Channel 0 is not used. • CHANN_ENB: Channel Enable Status 0 = if cleared, the DMA channel no longer transfers data, and may load the next descriptor if the UDPHS_DMACONTROLx register LDNXT_DSC bit is set. When any transfer is ended either due to an elapsed byte count or a UDPHS device initiated transfer end, this bit is automatically reset. 1 = if set, the DMA channel is currently enabled and transfers data upon request. This bit is normally set or cleared by writing into the UDPHS_DMACONTROLx register CHANN_ENB bit field either by software or descriptor loading. If a channel request is currently serviced when the UDPHS_DMACONTROLx register CHANN_ENB bit is cleared, the DMA FIFO buffer is drained until it is empty, then this status bit is cleared. • CHANN_ACT: Channel Active Status 0 = the DMA channel is no longer trying to source the packet data. When a packet transfer is ended this bit is automatically reset. 1 = the DMA channel is currently trying to source packet data, i.e. selected as the highest-priority requesting channel. When a packet transfer cannot be completed due to an END_BF_ST, this flag stays set during the next channel descriptor load (if any) and potentially until UDPHS packet transfer completion, if allowed by the new descriptor. • END_TR_ST: End of Channel Transfer Status 0 = cleared automatically when read by software. 1 = set by hardware when the last packet transfer is complete, if the UDPHS device has ended the transfer. Valid until the CHANN_ENB flag is cleared at the end of the next buffer transfer. • END_BF_ST: End of Channel Buffer Status 0 = cleared automatically when read by software. 1 = set by hardware when the BUFF_COUNT downcount reach zero. Valid until the CHANN_ENB flag is cleared at the end of the next buffer transfer. 1002 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • DESC_LDST: Descriptor Loaded Status 0 = cleared automatically when read by software. 1 = set by hardware when a descriptor has been loaded from the system bus. Valid until the CHANN_ENB flag is cleared at the end of the next buffer transfer. • BUFF_COUNT: Buffer Byte Count This field determines the current number of bytes still to be transferred for this buffer. This field is decremented from the AHB source bus access byte width at the end of this bus address phase. The access byte width is 4 by default, or less, at DMA start or end, if the start or end address is not aligned on a word boundary. At the end of buffer, the DMA accesses the UDPHS device only for the number of bytes needed to complete it. This field value is reliable (stable) only if the channel has been stopped or frozen (UDPHS_EPTCTLx register NT_DIS_DMA bit is used to disable the channel request) and the channel is no longer active CHANN_ACT flag is 0. Note: For OUT endpoints, if the receive buffer byte length (BUFF_LENGTH) has been defaulted to zero because the USB transfer length is unknown, the actual buffer byte length received will be 0x10000-BUFF_COUNT. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1003 39. DMA Controller (DMAC) 39.1 Description The DMA Controller (DMAC) is an AHB-central DMA controller core that transfers data from a source peripheral to a destination peripheral over one or more AMBA buses. One channel is required for each source/destination pair. In the most basic configuration, the DMAC has one master interface and one channel. The master interface reads the data from a source and writes it to a destination. Two AMBA transfers are required for each DMAC data transfer. This is also known as a dual-access transfer. The DMAC is programmed via the APB interface. The DMAC embeds four channels: DMAC Channel Number FIFO Size 0 8 Bytes 1 8 Bytes 2 8 Bytes 3 32 Bytes For hardware interface numbers, see Table 39-2, “Register Mapping,” on page 1021. 1004 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.2 Block Diagram Figure 39-1. DMA Controller (DMAC) Block Diagram DMAC Channel n APB Interface DMA Destination DMAC Channel 2 Status Registers DMAC Channel 1 DMAC Channel 0 DMAC Channel 0 Write data path to destination DMAC APB Interface Configuration Registers DMAC Destination Control State Machine Destination Pointer Management DMAC Interrupt Controller DMAC Interrupt DMA FIFO Controller DMA FIFO Trigger Manager External Triggers Soft Triggers DMAC Channel 0 Read data path from source DMAC Read Datapath Bundles DMAC REQ/ACK Interface DMAC Hardware Handshaking Interface DMAC Source Control State Machine Source Pointer Management DMA Source Requests Pool DMAC Write Datapath Bundles DMA Global Control and Data Mux DMA Global Request Arbiter DMAC AHB Lite Master Interface AMBA AHB SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1005 39.3 Functional Description 39.3.1 Basic Definitions Source peripheral: Device on an AMBA layer from where the DMAC reads data, which is then stored in the channel FIFO. The source peripheral teams up with a destination peripheral to form a channel. Destination peripheral: Device to which the DMAC writes the stored data from the FIFO (previously read from the source peripheral). Memory: Source or destination that is always “ready” for a DMAC transfer and does not require a handshaking interface to interact with the DMAC. Channel: Read/write datapath between a source peripheral on one configured AMBA layer and a destination peripheral on the same or different AMBA layer that occurs through the channel FIFO. If the source peripheral is not memory, then a source handshaking interface is assigned to the channel. If the destination peripheral is not memory, then a destination handshaking interface is assigned to the channel. Source and destination handshaking interfaces can be assigned dynamically by programming the channel registers. Master interface: DMAC is a master on the AHB bus reading data from the source and writing it to the destination over the AHB bus. Slave interface: The APB interface over which the DMAC is programmed. The slave interface in practice could be on the same layer as any of the master interfaces or on a separate layer. Handshaking interface: A set of signal registers that conform to a protocol and handshake between the DMAC and source or destination peripheral to control the transfer of a single or chunk transfer between them. This interface is used to request, acknowledge, and control a DMAC transaction. A channel can receive a request through one of two types of handshaking interface: hardware or software. Hardware handshaking interface: Uses hardware signals to control the transfer of a single or chunk transfer between the DMAC and the source or destination peripheral. Software handshaking interface: Uses software registers to contr5ol the transfer of a single or chunk transfer between the DMAC and the source or destination peripheral. No special DMAC handshaking signals are needed on the I/O of the peripheral. This mode is useful for interfacing an existing peripheral to the DMAC without modifying it. Flow controller: The device (either the DMAC or source/destination peripheral) that determines the length of and terminates a DMAC buffer transfer. If the length of a buffer is known before enabling the channel, then the DMAC should be programmed as the flow controller. Transfer hierarchy: Figure 39-2 on page 1007 illustrates the hierarchy between DMAC transfers, buffer transfers, chunk or single, and AMBA transfers (single or burst) for non-memory peripherals. Figure 39-3 on page 1007 shows the transfer hierarchy for memory. 1006 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 39-2. DMAC Transfer Hierarchy for Non-Memory Peripheral HDMA Transfer Buffer Buffer Chunk Transfer AMBA Burst Transfer Figure 39-3. DMA Transfer Level Buffer Transfer Level Buffer Chunk Transfer Chunk Transfer AMBA Single Transfer AMBA Burst Transfer AMBA Burst Transfer Single Transfer DMA Transaction Level AMBA Single Transfer AMBA Transfer Level DMAC Transfer Hierarchy for Memory HDMA Transfer Buffer AMBA Burst Transfer Buffer AMBA Burst Transfer DMA Transfer Level Buffer AMBA Burst Transfer AMBA Single Transfer Buffer Transfer Level AMBA Transfer Level Buffer: A buffer of DMAC data. The amount of data (length) is determined by the flow controller. For transfers between the DMAC and memory, a buffer is broken directly into a sequence of AMBA bursts and AMBA single transfers. For transfers between the DMAC and a non-memory peripheral, a buffer is broken into a sequence of DMAC transactions (single and chunks). These are in turn broken into a sequence of AMBA transfers. Transaction: A basic unit of a DMAC transfer as determined by either the hardware or software handshaking interface. A transaction is only relevant for transfers between the DMAC and a source or destination peripheral if the source or destination peripheral is a non-memory device. There are two types of transactions: single transfer and chunk transfer. ̶ Single transfer: The length of a single transaction is always 1 and is converted to a single AMBA access. ̶ Chunk transfer: The length of a chunk is programmed into the DMAC. The chunk is then converted into a sequence of AHB access.DMAC executes each AMBA burst transfer by performing incremental bursts that are no longer than 16 beats. DMAC transfer: Software controls the number of buffers in a DMAC transfer. Once the DMAC transfer has completed, then hardware within the DMAC disables the channel and can generate an interrupt to signal the completion of the DMAC transfer. You can then re-program the channel for a new DMAC transfer. Single-buffer DMAC transfer: Consists of a single buffer. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1007 Multi-buffer DMAC transfer: A DMAC transfer may consist of multiple DMAC buffers. Multi-buffer DMAC transfers are supported through buffer chaining (linked list pointers), auto-reloading of channel registers, and contiguous buffers. The source and destination can independently select which method to use. ̶ ̶ Linked lists (buffer chaining) – A descriptor pointer (DSCR) points to the location in system memory where the next linked list item (LLI) exists. The LLI is a set of registers that describe the next buffer (buffer descriptor) and a descriptor pointer register. The DMAC fetches the LLI at the beginning of every buffer when buffer chaining is enabled. Contiguous buffers – Where the address of the next buffer is selected to be a continuation from the end of the previous buffer. Channel locking: Software can program a channel to keep the AHB master interface by locking the arbitration for the master bus interface for the duration of a DMAC transfer, buffer, or chunk. Bus locking: Software can program a channel to maintain control of the AMBA bus by asserting hmastlock for the duration of a DMAC transfer, buffer, or transaction (single or chunk). Channel locking is asserted for the duration of bus locking at a minimum. 39.3.2 Memory Peripherals Figure 39-3 on page 1007 shows the DMAC transfer hierarchy of the DMAC for a memory peripheral. There is no handshaking interface with the DMAC, and therefore the memory peripheral can never be a flow controller. Once the channel is enabled, the transfer proceeds immediately without waiting for a transaction request. The alternative to not having a transaction-level handshaking interface is to allow the DMAC to attempt AMBA transfers to the peripheral once the channel is enabled. If the peripheral slave cannot accept these AMBA transfers, it inserts wait states onto the bus until it is ready; it is not recommended that more than 16 wait states be inserted onto the bus. By using the handshaking interface, the peripheral can signal to the DMAC that it is ready to transmit/receive data, and then the DMAC can access the peripheral without the peripheral inserting wait states onto the bus. 39.3.3 Handshaking Interface Handshaking interfaces are used at the transaction level to control the flow of single or chunk transfers. The operation of the handshaking interface is different and depends on whether the peripheral or the DMAC is the flow controller. The peripheral uses the handshaking interface to indicate to the DMAC that it is ready to transfer/accept data over the AMBA bus. A non-memory peripheral can request a DMAC transfer through the DMAC using one of two handshaking interfaces:  Hardware handshaking  Software handshaking Software selects between the hardware or software handshaking interface on a per-channel basis. Software handshaking is accomplished through memory-mapped registers, while hardware handshaking is accomplished using a dedicated handshaking interface. 39.3.3.1 Software Handshaking When the slave peripheral requires the DMAC to perform a DMAC transaction, it communicates this request by sending an interrupt to the CPU or interrupt controller. The interrupt service routine then uses the software registers to initiate and control a DMAC transaction. These software registers are used to implement the software handshaking interface. The SRC_H2SEL/DST_H2SEL bit in the DMAC_CFGx channel configuration register must be set to zero to enable software handshaking. When the peripheral is not the flow controller, then the last transaction register DMAC_LAST is not used, and the values in these registers are ignored. 1008 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.3.3.2 Chunk Transactions Writing a 1 to the DMAC_CREQ[2x] register starts a source chunk transaction request, where x is the channel number. Writing a 1 to the DMAC_CREQ[2x+1] register starts a destination chunk transfer request, where x is the channel number. Upon completion of the chunk transaction, the hardware clears the DMAC_CREQ[2x] or DMAC_CREQ[2x+1]. 39.3.3.3 Single Transactions Writing a 1 to the DMAC_SREQ[2x] register starts a source single transaction request, where x is the channel number. Writing a 1 to the DMAC_SREQ[2x+1] register starts a destination single transfer request, where x is the channel number. Upon completion of the chunk transaction, the hardware clears the DMAC_SREQ[x] or DMAC_SREQ[2x+1]. Software can poll the relevant channel bit in the DMAC_CREQ[2x]/DMAC_CREQ[2x+1] and DMAC_SREQ[x]/DMAC_SREQ[2x+1] registers. When both are 0, then either the requested chunk or single transaction has completed. 39.3.4 DMAC Transfer Types A DMAC transfer may consist of single or multi-buffers transfers. On successive buffers of a multi-buffer transfer, the DMAC_SADDRx/DMAC_DADDRx registers in the DMAC are reprogrammed using either of the following methods:  Buffer chaining using linked lists  Contiguous address between buffers On successive buffers of a multi-buffer transfer, the DMAC_CTRLAx and DMAC_CTRLBx registers in the DMAC are re-programmed using either of the following methods:  Buffer chaining using linked lists When buffer chaining, using linked lists is the multi-buffer method of choice, and on successive buffers, the DMAC_DSCRx register in the DMAC is re-programmed using the following method:  Buffer chaining using linked lists A buffer descriptor (LLI) consists of following registers, DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx, DMAC_CTRLAx, DMAC_CTRLBx.These registers, along with the DMAC_CFGx register, are used by the DMAC to set up and describe the buffer transfer. 39.3.4.1 Multi-buffer Transfers 39.3.4.2 Buffer Chaining Using Linked Lists In this case, the DMAC re-programs the channel registers prior to the start of each buffer by fetching the buffer descriptor for that buffer from system memory. This is known as an LLI update. DMAC buffer chaining is supported by using a Descriptor Pointer register (DMAC_DSCRx) that stores the address in memory of the next buffer descriptor. Each buffer descriptor contains the corresponding buffer descriptor (DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx, DMAC_CTRLAx DMAC_CTRLBx). To set up buffer chaining, a sequence of linked lists must be programmed in memory. The DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx, DMAC_CTRLAx and DMAC_CTRLBx registers are fetched from system memory on an LLI update. The updated content of the DMAC_CTRLAx register is written back to memory on buffer completion. Figure 39-4 on page 1010 shows how to use chained linked lists in memory to define multi-buffer transfers using buffer chaining. The Linked List multi-buffer transfer is initiated by programming DMAC_DSCRx with DSCRx(0) (LLI(0) base address) and DMAC_CTRLBx register with both SRC_DSCR and DST_DSCR set to 0. Other fields and registers are ignored and overwritten when the descriptor is retrieved from memory. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1009 The last transfer descriptor must be written to memory with its next descriptor address set to 0. Figure 39-4. Multi Buffer Transfer Using Linked List System Memory LLI(1) LLI(0) DSCRx(0) DSCRx(1)= DSCRx(0) + 0x10 DSCRx(2)= DSCRx(1) + 0x10 CTRLBx= DSCRx(0) + 0xC CTRLBx= DSCRx(1) + 0xC CTRLAx= DSCRx(0) + 0x8 CTRLBx= DSCRx(1) + 0x8 DADDRx= DSCRx(0) + 0x4 DADDRx= DSCRx(1) + 0x4 SADDRx= DSCRx(1) + 0x0 SADDRx= DSCRx(0) + 0x0 DSCRx(2) (points to 0 if LLI(1) is the last transfer descriptor DSCRx(1) 39.3.4.3 Programming DMAC for Multiple Buffer Transfers Table 39-1. Multiple Buffers Transfer Management Table Transfer Type AUTO SRC_REP DST_REP SRC_DSCR DST_DSCR BTSIZE SADDR DADDR Other Fields 1) Single Buffer or Last buffer of a multiple buffer transfer 0 – – 1 1 USR USR USR USR 2) Multi Buffer transfer with contiguous DADDR 0 – 0 0 1 LLI LLI CONT LLI 3) Multi Buffer transfer with contiguous SADDR 0 0 – 1 0 LLI CONT LLI LLI 4) Multi Buffer transfer with LLI support 0 – – 0 0 LLI LLI LLI LLI Notes: 1. USR means that the register field is manually programmed by the user. 2. CONT means that address are contiguous. 3. LLI means that the register field is updated with the content of the linked list item. 39.3.4.4 Contiguous Address Between Buffers In this case, the address between successive buffers is selected to be a continuation from the end of the previous buffer. Enabling the source or destination address to be contiguous between buffers is a function of DMAC_CTRLAx.SRC_DSCR and DMAC_CTRLAx.DST_DSCR registers. 39.3.4.5 Suspension of Transfers Between buffers At the end of every buffer transfer, an end of buffer interrupt is asserted if:  Note: the channel buffer interrupt is unmasked, DMAC_EBCIMR.BTC[n] = ‘1’, where n is the channel number. The buffer complete interrupt is generated at the completion of the buffer transfer to the destination. At the end of a chain of multiple buffers, an end of linked list interrupt is asserted if:  1010 the channel end of chained buffer interrupt is unmasked, DMAC_EBCIMR.CBTC[n] = ‘1’, when n is the channel number. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.3.4.6 Ending Multi-buffer Transfers All multi-buffer transfers must end as shown in Row 1 of Table 39-1 on page 1010. At the end of every buffer transfer, the DMAC samples the row number, and if the DMAC is in Row 1 state, then the previous buffer transferred was the last buffer and the DMAC transfer is terminated. For rows 2, 3, and 4 the user must setup the last buffer descriptor in memory such that both LLI.DMAC_CTRLBx.SRC_DSCR and LLI.DMAC_CTRLBx.DST_DSCR are one and LLI.DMAC_DSCRx is set to 0. 39.3.5 Programming a Channel Four registers, the DMAC_DSCRx, the DMAC_CTRLAx, the DMAC_CTRLBx and DMAC_CFGx, need to be programmed to set up whether single or multi-buffer transfers take place, and which type of multi-buffer transfer is used. The different transfer types are shown in Table 39-1 on page 1010. The “BTSIZE, SADDR and DADDR” columns indicate where the values of DMAC_SARx, DMAC_DARx, DMAC_CTLx, and DMAC_LLPx are obtained for the next buffer transfer when multi-buffer DMAC transfers are enabled. 39.3.5.1 Programming Examples 39.3.5.2 Single-buffer Transfer (Row 1) 1. Read the Channel Handler Status Register DMAC_CHSR.ENABLE Field to choose a free (disabled) channel. 2. Clear any pending interrupts on the channel from the previous DMAC transfer by reading the interrupt status register, DMAC_EBCISR. 3. Program the following channel registers: a. Write the starting source address in the DMAC_SADDRx register for channel x. b. Write the starting destination address in the DMAC_DADDRx register for channel x. c. Program DMAC_CTRLAx, DMAC_CTRLBx and DMAC_CFGx according to Row 1 as shown in Table 39-1 on page 1010. Program the DMAC_CTRLBx register with both DST_DSCR and SRC_DSCR fields set to one. d. Write the control information for the DMAC transfer in the DMAC_CTRLAx and DMAC_CTRLBx registers for channel x. For example, in the register, you can program the following: ̶ ̶ i. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control device by programming the FC of the DMAC_CTRLBx register. ii. Set up the transfer characteristics, such as: – Transfer width for the source in the SRC_WIDTH field. – Transfer width for the destination in the DST_WIDTH field. – Incrementing/decrementing or fixed address for source in SRC_INC field. – Incrementing/decrementing or fixed address for destination in DST_INC field. e. Write the channel configuration information into the DMAC_CFGx register for channel x. ̶ ̶ i. Designate the handshaking interface type (hardware or software) for the source and destination peripherals. This is not required for memory. This step requires programming the SRC_H2SEL/DST_H2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking interface to handle source/destination requests. Writing a ‘0’ activates the software handshaking interface to handle source/destination requests. ii. If the hardware handshaking interface is activated for the source or destination peripheral, assign a handshaking interface to the source and destination peripheral. This requires programming the SRC_PER and DST_PER bits, respectively. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1011 4. After the DMAC selected channel has been programmed, enable the channel by writing a ‘1’ to the DMAC_CHER.ENABLE[n] bit, where n is the channel number. Make sure that bit 0 of DMAC_EN.ENABLE register is enabled. 5. Source and destination request single and chunk DMAC transactions to transfer the buffer of data (assuming non-memory peripherals). The DMAC acknowledges at the completion of every transaction (chunk and single) in the buffer and carry out the buffer transfer. 6. Once the transfer completes, hardware sets the interrupts and disables the channel. At this time you can either respond to the buffer Complete or Transfer Complete interrupts, or poll for the Channel Handler Status Register (DMAC_CHSR.ENABLE[n]) bit until it is cleared by hardware, to detect when the transfer is complete. 39.3.5.3 Multi-buffer Transfer with Linked List for Source and Linked List for Destination (Row 4) 1. Read the Channel Enable register to choose a free (disabled) channel. 2. Set up the chain of Linked List Items (otherwise known as buffer descriptors) in memory. Write the control information in the LLI.DMAC_CTRLAx and LLI.DMAC_CTRLBx registers location of the buffer descriptor for each LLI in memory (see Figure 39-5 on page 1013) for channel x. For example, in the register, you can program the following: a. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control device by programming the FC of the DMAC_CTRLBx register. b. Set up the transfer characteristics, such as: ̶ ̶ 3. i. Transfer width for the source in the SRC_WIDTH field. ii. Transfer width for the destination in the DST_WIDTH field. ̶ v. Incrementing/decrementing or fixed address for source in SRC_INCR field. ̶ vi. Incrementing/decrementing or fixed address for destination DST_INCR field. Write the channel configuration information into the DMAC_CFGx register for channel x. a. Designate the handshaking interface type (hardware or software) for the source and destination peripherals. This is not required for memory. This step requires programming the SRC_H2SEL/DST_H2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking interface to handle source/destination requests for the specific channel. Writing a ‘0’ activates the software handshaking interface to handle source/destination requests. b. If the hardware handshaking interface is activated for the source or destination peripheral, assign the handshaking interface to the source and destination peripheral. This requires programming the SRC_PER and DST_PER bits, respectively. 4. Make sure that the LLI.DMAC_CTRLBx register locations of all LLI entries in memory (except the last) are set as shown in Row 4 of Table 39-1 on page 1010. The LLI.DMAC_CTRLBx register of the last Linked List Item must be set as described in Row 1 of Table 39-1. Figure 39-4 on page 1010 shows a Linked List example with two list items. 5. Make sure that the LLI.DMAC_DSCRx register locations of all LLI entries in memory (except the last) are non-zero and point to the base address of the next Linked List Item. 6. Make sure that the LLI.DMAC_SADDRx/LLI.DMAC_DADDRx register locations of all LLI entries in memory point to the start source/destination buffer address preceding that LLI fetch. 7. Make sure that the LLI.DMAC_CTRLAx.DONE field of the LLI.DMAC_CTRLAx register locations of all LLI entries in memory are cleared. 8. If source picture-picture mode is enabled (DMAC_CTRLBx.SRC_PIP is enabled), program the DMAC_SPIPx register for channel x. 9. If destination picture-in-picture is enabled (DMAC_CTRLBx.DST_PIP is enabled), program the DMAC_DPIPx register for channel x. 10. Clear any pending interrupts on the channel from the previous DMAC transfer by reading the status register: DMAC_EBCISR. 1012 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 11. Program the DMAC_CTRLBx, DMAC_CFGx registers according to Row 4 as shown in Table 39-1 on page 1010. 12. Program the DMAC_DSCRx register with DMAC_DSCRx(0), the pointer to the first Linked List item. 13. Finally, enable the channel by writing a ‘1’ to the DMAC_CHER.ENABLE[n] bit, where n is the channel number. The transfer is performed. 14. The DMAC fetches the first LLI from the location pointed to by DMAC_DSCRx(0). Note: The LLI.DMAC_SADDRx, LLI. DMAC_DADDRx, LLI.DMAC_DSCRx, LLI.DMAC_CTRLAx and LLI.DMAC_CTRLBx registers are fetched. The DMAC automatically reprograms the DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx, DMAC_CTRLBx and DMAC_CTRLAx channel registers from the DMAC_DSCRx(0). 15. Source and destination request single and chunk DMAC transactions to transfer the buffer of data (assuming non-memory peripheral). The DMAC acknowledges at the completion of every transaction (chunk and single) in the buffer and carry out the buffer transfer. 16. Once the buffer of data is transferred, the DMAC_CTRLAx register is written out to system memory at the same location and on the same layer where it was originally fetched, that is, the location of the DMAC_CTRLAx register of the linked list item fetched prior to the start of the buffer transfer. Only DMAC_CTRLAx register is written out because only the DMAC_CTRLAx.BTSIZE and DMAC_CTRLAX.DONE bits have been updated by DMAC hardware. Additionally, the DMAC_CTRLAx.DONE bit is asserted when the buffer transfer has completed. Note: Do not poll the DMAC_CTRLAx.DONE bit in the DMAC memory map. Instead, poll the LLI.DMAC_CTRLAx.DONE bit in the LLI for that buffer. If the poll LLI.DMAC_CTRLAx.DONE bit is asserted, then this buffer transfer has completed. This LLI.DMAC_CTRLAx.DONE bit was cleared at the start of the transfer. 17. The DMAC does not wait for the buffer interrupt to be cleared, but continues fetching the next LLI from the memory location pointed to by current DMAC_DSCRx register and automatically reprograms the DMAC_SADDRx, DMAC_DADDRx, DMAC_DSCRx, DMAC_CTRLAx and DMAC_CTRLBx channel registers. The DMAC transfer continues until the DMAC determines that the DMAC_CTRLBx and DMAC_DSCRx registers at the end of a buffer transfer match described in Row 1 of Table 39-1 on page 1010. The DMAC then knows that the previous buffer transferred was the last buffer in the DMAC transfer. The DMAC transfer might look like that shown in Figure 39-5 on page 1013. Figure 39-5. Multi-buffer with Linked List Address for Source and Destination Address of Destination Layer Address of Source Layer Buffer 2 SADDR(2) Buffer 2 DADDR(2) Buffer 1 SADDR(1) Buffer 1 DADDR(1) Buffer 0 Buffer 0 DADDR(0) SADDR(0) Source Buffers Destination Buffers SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1013 If the user needs to execute a DMAC transfer where the source and destination address are contiguous but the amount of data to be transferred is greater than the maximum buffer size DMAC_CTRLAx.BTSIZE, then this can be achieved using the type of multi-buffer transfer as shown in Figure 39-6 on page 1014. Figure 39-6. Multi-buffer with Linked Address for Source and Destination Buffers are Contiguous Address of Source Layer Address of Destination Layer Buffer 2 DADDR(3) Buffer 2 Buffer 2 SADDR(3) DADDR(2) Buffer 2 Buffer 1 SADDR(2) DADDR(1) Buffer 1 Buffer 0 SADDR(1) DADDR(0) Buffer 0 SADDR(0) Source Buffers The DMAC transfer flow is shown in Figure 39-7 on page 1015. 1014 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Destination Buffers Figure 39-7. DMAC Transfer Flow for Source and Destination Linked List Address Channel enabled by software LLI Fetch Hardware reprograms SADDRx, DADDRx, CTRLA/Bx, DSCRx DMAC buffer transfer Writeback of HDMA_CTRLAx register in system memory Buffer Complete interrupt generated here Is HDMA in Row1 of HDMA State Machine Table? HDMA Transfer Complete interrupt generated here no yes Channel Disabled by hardware SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1015 39.3.5.4 Multi-buffer DMAC Transfer with Linked List for Source and Contiguous Destination Address (Row 2) 1. Read the Channel Enable register to choose a free (disabled) channel. 2. Set up the linked list in memory. Write the control information in the LLI.DMAC_CTRLAx and LLI.DMAC_CTRLBx register location of the buffer descriptor for each LLI in memory for channel x. For example, in the register, you can program the following: a. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control device by programming the FC of the DMAC_CTRLBx register. b. Set up the transfer characteristics, such as: ̶ ̶ ̶ vi. Incrementing/decrementing or fixed address for destination DST_INCR field. Write the starting destination address in the DMAC_DADDRx register for channel x. Note: 4. ii. Transfer width for the destination in the DST_WIDTH field. v. Incrementing/decrementing or fixed address for source in SRC_INCR field. ̶ 3. i. Transfer width for the source in the SRC_WIDTH field. The values in the LLI.DMAC_DADDRx register location of each Linked List Item (LLI) in memory, although fetched during an LLI fetch, are not used. Write the channel configuration information into the DMAC_CFGx register for channel x. a. Designate the handshaking interface type (hardware or software) for the source and destination peripherals. This is not required for memory. This step requires programming the SRC_H2SEL/DST_H2SEL bits, respectively. Writing a ‘1’ activates the hardware handshaking interface to handle source/destination requests for the specific channel. Writing a ‘0’ activates the software handshaking interface to handle source/destination requests. b. If the hardware handshaking interface is activated for the source or destination peripheral, assign handshaking interface to the source and destination peripherals. This requires programming the SRC_PER and DST_PER bits, respectively. 5. Make sure that all LLI.DMAC_CTRLBx register locations of the LLI (except the last) are set as shown in Row 2 of Table 39-1 on page 1010, while the LLI.DMAC_CTRLBx register of the last Linked List item must be set as described in Row 1 of Table 39-1. Figure 39-4 on page 1010 shows a Linked List example with two list items. 6. Make sure that the LLI.DMAC_DSCRx register locations of all LLIs in memory (except the last) are non-zero and point to the next Linked List Item. 7. Make sure that the LLI.DMAC_SADDRx register location of all LLIs in memory point to the start source buffer address proceeding that LLI fetch. 8. Make sure that the LLI.DMAC_CTRLAx.DONE field of the LLI.DMAC_CTRLAx register locations of all LLIs in memory is cleared. 9. Clear any pending interrupts on the channel from the previous DMAC transfer by reading the interrupt status register. 10. Program the DMAC_CTRLAx, DMAC_CTRLBx and DMAC_CFGx registers according to Row 2 as shown in Table 39-1 on page 1010 11. Program the DMAC_DSCRx register with DMAC_DSCRx(0), the pointer to the first Linked List item. 12. Finally, enable the channel by writing a ‘1’ to the DMAC_CHER.ENABLE[n] bit. The transfer is performed. Make sure that bit 0 of the DMAC_EN register is enabled. 13. The DMAC fetches the first LLI from the location pointed to by DMAC_DSCRx(0). Note: The LLI.DMAC_SADDRx, LLI.DMAC_DADDRx, LLI.DMAC_DSCRx and LLI.DMAC_CTRLA/Bx registers are fetched. The LLI.DMAC_DADDRx register location of the LLI although fetched is not used. The DMAC_DADDRx register in the DMAC remains unchanged. 14. Source and destination requests single and chunk DMAC transactions to transfer the buffer of data (assuming non-memory peripherals). The DMAC acknowledges at the completion of every transaction (chunk and single) in the buffer and carry out the buffer transfer 1016 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 15. Once the buffer of data is transferred, the DMAC_CTRLAx register is written out to system memory at the same location and on the same layer (DMAC_DSCRx.DSCR_IF) where it was originally fetched, that is, the location of the DMAC_CTRLAx register of the linked list item fetched prior to the start of the buffer transfer. Only DMAC_CTRLAx register is written out because only the DMAC_CTRLAx.BTSIZE and DMAC_CTRLAX.DONE fields have been updated by DMAC hardware. Additionally, the DMAC_CTRLAx.DONE bit is asserted when the buffer transfer has completed. Note: Do not poll the DMAC_CTRLAx.DONE bit in the DMAC memory map. Instead, poll the LLI.DMAC_CTRLAx.DONE bit in the LLI for that buffer. If the poll LLI.DMAC_CTRLAx.DONE bit is asserted, then this buffer transfer has completed. This LLI.DMAC_CTRLAx.DONE bit was cleared at the start of the transfer. 16. The DMAC does not wait for the buffer interrupt to be cleared, but continues and fetches the next LLI from the memory location pointed to by current DMAC_DSCRx register and automatically reprograms the DMAC_SADDRx, DMAC_CTRLAx, DMAC_CTRLBx and DMAC_DSCRx channel registers. The DMAC_DADDRx register is left unchanged. The DMAC transfer continues until the DMAC samples the DMAC_CTRLAx, DMAC_CTRLBx and DMAC_DSCRx registers at the end of a buffer transfer match that described in Row 1 of Table 39-1 on page 1010. The DMAC then knows that the previous buffer transferred was the last buffer in the DMAC transfer. The DMAC transfer might look like that shown in Figure 39-8 on page 1017 Note that the destination address is decrementing. Figure 39-8. DMAC Transfer with Linked List Source Address and Contiguous Destination Address Address of Source Layer Address of Destination Layer Buffer 2 SADDR(2) Buffer 2 DADDR(2) Buffer 1 Buffer 1 SADDR(1) DADDR(1) Buffer 0 DADDR(0) Buffer 0 SADDR(0) Source Buffers Destination Buffers The DMAC transfer flow is shown in Figure 39-9 on page 1018. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1017 Figure 39-9. DMAC Transfer Flow for Linked List Source Address and Contiguous Destination Address Channel Enabled by software LLI Fetch Hardware reprograms SADDRx, CTRLAx,CTRLBx, DSCRx HDMA buffer transfer Writeback of control information of LLI Buffer Complete interrupt generated here Is HDMA in Row 1 ? HDMA Transfer Complete interrupt generated here yes Channel Disabled by hardware 1018 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 no 39.3.6 Disabling a Channel Prior to Transfer Completion Under normal operation, software enables a channel by writing a ‘1’ to the Channel Handler Enable Register, DMAC_CHER.ENABLE[n], and hardware disables a channel on transfer completion by clearing the DMAC_CHSR.ENABLE[n] register bit. The recommended way for software to disable a channel without losing data is to use the SUSPEND[n] bit in conjunction with the EMPTY[n] bit in the Channel Handler Status Register. 1. If software wishes to disable a channel n prior to the DMAC transfer completion, then it can set the DMAC_CHER.SUSPEND[n] bit to tell the DMAC to halt all transfers from the source peripheral. Therefore, the channel FIFO receives no new data. 2. Software can now poll the DMAC_CHSR.EMPTY[n] bit until it indicates that the channel n FIFO is empty, where n is the channel number. 3. The DMAC_CHER.ENABLE[n] bit can then be cleared by software once the channel n FIFO is empty, where n is the channel number. When DMAC_CTRLAx.SRC_WIDTH is less than DMAC_CTRLAx.DST_WIDTH and the DMAC_CHSRx.SUSPEND[n] bit is high, the DMAC_CHSRx.EMPTY[n] is asserted once the contents of the FIFO do not permit a single word of DMAC_CTRLAx.DST_WIDTH to be formed. However, there may still be data in the channel FIFO but not enough to form a single transfer of DMAC_CTLx.DST_WIDTH width. In this configuration, once the channel is disabled, the remaining data in the channel FIFO are not transferred to the destination peripheral. It is permitted to remove the channel from the suspension state by writing a ‘1’ to the DMAC_CHER.RESUME[n] field register. The DMAC transfer completes in the normal manner. n defines the channel number. Note: If a channel is disabled by software, an active single or chunk transaction is not guaranteed to receive an acknowledgement. 39.3.6.1 Abnormal Transfer Termination A DMAC transfer may be terminated abruptly by software by clearing the channel enable bit, DMAC_CHDR.ENABLE[n] where n is the channel number. This does not mean that the channel is disabled immediately after the DMAC_CHSR.ENABLE[n] bit is cleared over the APB interface. Consider this as a request to disable the channel. The DMAC_CHSR.ENABLE[n] must be polled and then it must be confirmed that the channel is disabled by reading back 0. Software may terminate all channels abruptly by clearing the global enable bit in the DMAC Configuration Register (DMAC_EN.ENABLE bit). Again, this does not mean that all channels are disabled immediately after the DMAC_EN.ENABLE is cleared over the APB slave interface. Consider this as a request to disable all channels. The DMAC_CHSR.ENABLE must be polled and then it must be confirmed that all channels are disabled by reading back ‘0’. Note: Note: If the channel enable bit is cleared while there is data in the channel FIFO, this data is not sent to the destination peripheral and is not present when the channel is re-enabled. For read sensitive source peripherals, such as a source FIFO, this data is therefore lost. When the source is not a read sensitive device (i.e., memory), disabling a channel without waiting for the channel FIFO to empty may be acceptable as the data is available from the source peripheral upon request and is not lost. If a channel is disabled by software, an active single or chunk transaction is not guaranteed to receive an acknowledgement. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1019 39.4 1020 DMAC Software Requirements  There must not be any write operation to Channel registers in an active channel after the channel enable is made HIGH. If any channel parameters must be reprogrammed, this can only be done after disabling the DMAC channel.  You must program the DMAC_SADDRx and DMAC_DADDRx channel registers with a byte, half-word and word aligned address depending on the source width and destination width.  After the software disables a channel by writing into the channel disable register, it must re-enable the channel only after it has polled a 0 in the corresponding channel enable status register. This is because the current AHB Burst must terminate properly.  If you program the BTSIZE field in the DMAC_CTRLA, as zero, and the DMAC is defined as the flow controller, then the channel is automatically disabled.  When hardware handshaking interface protocol is fully implemented, a peripheral is expected to deassert any sreq or breq signals on receiving the ack signal irrespective of the request the ack was asserted in response to.  Multiple Transfers involving the same peripheral must not be programmed and enabled on different channel, unless this peripheral integrates several hardware handshaking interface.  When a Peripheral is flow controller, the targeted DMAC Channel must be enabled before the Peripheral. If you do not ensure this the DMAC Channel might miss a Last Transfer Flag, if the First DMAC request is also the last transfer. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5 DMA Controller (DMAC) User Interface Table 39-2. Register Mapping Offset Register Name Access Reset 0x000 DMAC Global Configuration Register DMAC_GCFG Read-write 0x10 0x004 DMAC Enable Register DMAC_EN Read-write 0x0 0x008 DMAC Software Single Request Register DMAC_SREQ Read-write 0x0 0x00C DMAC Software Chunk Transfer Request Register DMAC_CREQ Read-write 0x0 0x010 DMAC Software Last Transfer Flag Register DMAC_LAST Read-write 0x0 0x014 Reserved – – – 0x018 DMAC Error, Chained Buffer transfer completed and Buffer transfer completed Interrupt Enable register. DMAC_EBCIER Write-only – 0x01C DMAC Error, Chained Buffer transfer completed and Buffer transfer completed Interrupt Disable register. DMAC_EBCIDR Write-only – 0x020 DMAC Error, Chained Buffer transfer completed and Buffer transfer completed Mask Register. DMAC_EBCIMR Read-only 0x0 0x024 DMAC Error, Chained Buffer transfer completed and Buffer transfer completed Status Register. DMAC_EBCISR Read-only 0x0 0x028 DMAC Channel Handler Enable Register DMAC_CHER Write-only – 0x02C DMAC Channel Handler Disable Register DMAC_CHDR Write-only – 0x030 DMAC Channel Handler Status Register DMAC_CHSR Read-only 0x00FF0000 0x034 Reserved – – – 0x038 Reserved – – – 0x03C+ch_num*(0x28)+(0x0) DMAC Channel Source Address Register DMAC_SADDR Read-write 0x0 0x03C+ch_num*(0x28)+(0x4) DMAC Channel Destination Address Register DMAC_DADDR Read-write 0x0 0x03C+ch_num*(0x28)+(0x8) DMAC Channel Descriptor Address Register DMAC_DSCR Read-write 0x0 0x03C+ch_num*(0x28)+(0xC) DMAC Channel Control A Register DMAC_CTRLA Read-write 0x0 0x03C+ch_num*(0x28)+(0x10) DMAC Channel Control B Register DMAC_CTRLB Read-write 0x0 0x03C+ch_num*(0x28)+(0x14) DMAC Channel Configuration Register DMAC_CFG Read-write 0x01000000 0x03C+ch_num*(0x28)+(0x18) Reserved – – – 0x03C+ch_num*(0x28)+(0x1C) Reserved – – – 0x03C+ch_num*(0x28)+(0x20) Reserved – – – 0x03C+ch_num*(0x28)+(0x24) Reserved – – – Read-write 0x0 – – (1) 0x064 - 0xC8 DMAC Channel 1 to 3 Register 0x017C- 0x1FC Reserved Note: – 1. The addresses for the DMAC registers shown here are for DMA Channel 0. This sequence of registers is repeated successively for each DMA channel located between 0x064 and 0xC8. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1021 39.5.1 DMAC Global Configuration Register Name: DMAC_GCFG Address: 0x400B0000 Access: Read-write Reset: 0x00000010 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 ARB_CFG 3 – 2 – 1 – 0 – • ARB_CFG 0: Fixed priority arbiter. 1: Modified round robin arbiter. 1022 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.2 DMAC Enable Register Name: DMAC_EN Address: 0x400B0004 Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 ENABLE • ENABLE 0: DMA Controller is disabled. 1: DMA Controller is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1023 39.5.3 DMAC Software Single Request Register Name: DMAC_SREQ Address: 0x400B0008 Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 DSREQ3 6 SSREQ3 5 DSREQ2– 4 SSREQ2– 3 DSREQ1 2 SSREQ1 1 DSREQ0 0 SSREQ0 • DSREQx Request a destination single transfer on channel i. • SSREQx Request a source single transfer on channel i. 1024 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.4 DMAC Software Chunk Transfer Request Register Name: DMAC_CREQ Address: 0x400B000C Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 DCREQ3 6 SCREQ3 5 DCREQ2– 4 SCREQ2– 3 DCREQ1 2 SCREQ1 1 DCREQ0 0 SCREQ0 • DCREQx Request a destination chunk transfer on channel i. • SCREQx Request a source chunk transfer on channel i. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1025 39.5.5 DMAC Software Last Transfer Flag Register Name: DMAC_LAST Address: 0x400B0010 Access: Read-write Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 DLAST3 6 SLAST3 5 DLAST2 4 SLAST2 3 DLAST1 2 SLAST1 1 DLAST0 0 SLAST0 • DLASTx Writing one to DLASTx prior to writing one to DSREQx or DCREQx indicates that this destination request is the last transfer of the buffer. • SLASTx Writing one to SLASTx prior to writing one to SSREQx or SCREQx indicates that this source request is the last transfer of the buffer. 1026 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.6 DMAC Error, Buffer Transfer and Chained Buffer Transfer Interrupt Enable Register Name: DMAC_EBCIER Address: 0x400B0018 Access: Write-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 ERR3 18 ERR2 17 ERR1 16 ERR0 15 – 14 – 13 – 12 – 11 CBTC3 10 CBTC2 9 CBTC1 8 CBTC0 7 – 6 – 5 – 4 – 3 BTC3 2 BTC2 1 BTC1 0 BTC0 • BTC[3:0] Buffer Transfer Completed Interrupt Enable Register. Set the relevant bit in the BTC field to enable the interrupt for channel i. • CBTC[3:0] Chained Buffer Transfer Completed Interrupt Enable Register. Set the relevant bit in the CBTC field to enable the interrupt for channel i. • ERR[3:0] Access Error Interrupt Enable Register. Set the relevant bit in the ERR field to enable the interrupt for channel i. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1027 39.5.7 DMAC Error, Buffer Transfer and Chained Buffer Transfer Interrupt Disable Register Name: DMAC_EBCIDR Address: 0x400B001C Access: Write-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 ERR3 18 ERR2 17 ERR1 16 ERR0 15 – 14 – 13 – 12 – 11 CBTC3 10 CBTC2 9 CBTC1 8 CBTC0 7 – 6 – 5 – 4 – 3 BTC3 2 BTC2 1 BTC1 0 BTC0 • BTC[3:0] Buffer transfer completed Disable Interrupt Register. When set, a bit of the BTC field disables the interrupt from the relevant DMAC channel. • CBTC[3:0] Chained Buffer transfer completed Disable Register. When set, a bit of the CBTC field disables the interrupt from the relevant DMAC channel. • ERR[3:0] Access Error Interrupt Disable Register. When set, a bit of the ERR field disables the interrupt from the relevant DMAC channel. 1028 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.8 DMAC Error, Buffer Transfer and Chained Buffer Transfer Interrupt Mask Register Name: DMAC_EBCIMR Address: 0x400B0020 Access: Read-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 ERR3 18 ERR2 17 ERR1 16 ERR0 15 – 14 – 13 – 12 – 11 CBTC3 10 CBTC2 9 CBTC1 8 CBTC0 7 – 6 – 5 – 4 – 3 BTC3 2 BTC2 1 BTC1 0 BTC0 • BTC[3:0] 0: Buffer Transfer completed interrupt is disabled for channel i. 1: Buffer Transfer completed interrupt is enabled for channel i. • CBTC[3:0] 0: Chained Buffer Transfer interrupt is disabled for channel i. 1: Chained Buffer Transfer interrupt is enabled for channel i. • ERR[3:0] 0: Transfer Error Interrupt is disabled for channel i. 1: Transfer Error Interrupt is enabled for channel i. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1029 39.5.9 DMAC Error, Buffer Transfer and Chained Buffer Transfer Status Register Name: DMAC_EBCISR Address: 0x400B0024 Access: Read-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 ERR3 18 ERR2 17 ERR1 16 ERR0 15 – 14 – 13 – 12 – 11 CBTC3 10 CBTC2 9 CBTC1 8 CBTC0 7 – 6 – 5 – 4 – 3 BTC3 2 BTC2 1 BTC1 0 BTC0 • BTC[3:0] When BTC[i] is set, Channel i buffer transfer has terminated. • CBTC[3:0] When CBTC[i] is set, Channel i Chained buffer has terminated. LLI Fetch operation is disabled. • ERR[3:0] When ERR[i] is set, Channel i has detected an AHB Read or Write Error Access. 1030 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.10 DMAC Channel Handler Enable Register Name: DMAC_CHER Address: 0x400B0028 Access: Write-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 KEEP3 26 KEEP2 25 KEEP1 24 KEEP0 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 SUSP3 10 SUSP2 9 SUSP1 8 SUSP0 7 – 6 – 5 – 4 – 3 ENA3 2 ENA2 1 ENA1 0 ENA0 • ENA[3:0] When set, a bit of the ENA field enables the relevant channel. • SUSP[3:0] When set, a bit of the SUSP field freezes the relevant channel and its current context. • KEEP[3:0] When set, a bit of the KEEP field resumes the current channel from an automatic stall state. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1031 39.5.11 DMAC Channel Handler Disable Register Name: DMAC_CHDR Address: 0x400B002C Access: Write-only Reset: 0x00000000 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 RES3 10 RES2 9 RES1 8 RES0 7 – 6 – 5 – 4 – 3 DIS3 2 DIS2 1 DIS1 0 DIS0 • DIS[3:0] Write one to this field to disable the relevant DMAC Channel. The content of the FIFO is lost and the current AHB access is terminated. Software must poll DIS[3:0] field in the DMAC_CHSR register to be sure that the channel is disabled. • RES[3:0] Write one to this field to resume the channel transfer restoring its context. 1032 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.12 DMAC Channel Handler Status Register Name: DMAC_CHSR Address: 0x400B0030 Access: Read-only Reset: 0x00FF0000 31 – 30 – 29 – 28 – 27 STAL3 26 STAL2 25 STAL1 24 STAL0 23 – 22 – 21 – 20 – 19 EMPT3 18 EMPT2 17 EMPT1 16 EMPT0 15 – 14 – 13 – 12 – 11 SUSP3 10 SUSP2 9 SUSP1 8 SUSP0 7 – 6 – 5 – 4 – 3 ENA3 2 ENA2 1 ENA1 0 ENA0 • ENA[3:0] A one in any position of this field indicates that the relevant channel is enabled. • SUSP[3:0] A one in any position of this field indicates that the channel transfer is suspended. • EMPT[3:0] A one in any position of this field indicates that the relevant channel is empty. • STAL[3:0] A one in any position of this field indicates that the relevant channel is stalling. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1033 39.5.13 DMAC Channel x [x = 0..3] Source Address Register Name: DMAC_SADDRx [x = 0..3] Addresses: 0x400B003C [0], 0x400B0064 [1], 0x400B008C [2], 0x400B00B4 [3] Access: Read-write Reset: 0x00000000 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 SADDRx 23 22 21 20 SADDRx 15 14 13 12 SADDRx 7 6 5 4 SADDRx • SADDRx Channel x source address. This register must be aligned with the source transfer width. 1034 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.14 DMAC Channel x [x = 0..3] Destination Address Register Name: DMAC_DADDRx [x = 0..3] Addresses: 0x400B0040 [0], 0x400B0068 [1], 0x400B0090 [2], 0x400B00B8 [3] Access: Read-write Reset: 0x00000000 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 0 DADDRx 23 22 21 20 DADDRx 15 14 13 12 DADDRx 7 6 5 4 DADDRx • DADDRx Channel x destination address. This register must be aligned with the destination transfer width. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1035 39.5.15 DMAC Channel x [x = 0..3] Descriptor Address Register Name: DMAC_DSCRx [x = 0..3] Addresses: 0x400B0044 [0], 0x400B006C [1], 0x400B0094 [2], 0x400B00BC [3] Access: Read-write Reset: 0x00000000 31 30 29 28 27 26 25 24 19 18 17 16 11 10 9 8 3 2 1 DSCRx 23 22 21 20 DSCRx 15 14 13 12 DSCRx 7 6 5 4 DSCRx • DSCRx Buffer Transfer descriptor address. This address is word aligned. 1036 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 0 – 39.5.16 DMAC Channel x [x = 0..3] Control A Register Name: DMAC_CTRLAx [x = 0..3] Addresses: 0x400B0048 [0], 0x400B0070 [1], 0x400B0098 [2], 0x400B00C0 [3] Access: Read-write Reset: 0x00000000 31 DONE 30 – 29 23 – 22 – 21 – 15 14 13 28 27 – 26 – 25 20 DCSIZE 19 – 18 – 17 – 16 SCSIZE 12 11 10 9 8 1 0 DST_WIDTH 24 SRC_WIDTH BTSIZE 7 6 5 4 3 2 BTSIZE • BTSIZE Buffer Transfer Size. The transfer size relates to the number of transfers to be performed, that is, for writes it refers to the number of source width transfers to perform when DMAC is flow controller. For Reads, BTSIZE refers to the number of transfers completed on the Source Interface. When this field is set to 0, the DMAC module is automatically disabled when the relevant channel is enabled. • SCSIZE Source Chunk Transfer Size. SCSIZE value Number of data transferred 0 1 1 4 • DCSIZE Destination Chunk Transfer size. DCSIZE Number of data transferred 0 1 1 4 • SRC_WIDTH SRC_WIDTH Single Transfer Size 00 BYTE 01 HALF-WORD 1X WORD SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1037 • DST_WIDTH DST_WIDTH Single Transfer Size 00 BYTE 01 HALF-WORD 1X WORD • DONE 0: The transfer is performed. 1: If SOD field of DMAC_CFG register is set to true, then the DMAC is automatically disabled when an LLI updates the content of this register. The DONE field is written back to memory at the end of the transfer. 1038 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.17 DMAC Channel x [x = 0..3] Control B Register Name: DMAC_CTRLBx [x = 0..3] Addresses: 0x400B004C [0], 0x400B0074 [1], 0x400B009C [2], 0x400B00C4 [3] Access: Read-write Reset: 0x00000000 31 – 30 IEN 23 – 22 15 – 7 – 29 28 DST_INCR 27 – 26 – 25 24 SRC_INCR 21 20 DST_DSCR 19 – 18 – 17 – 16 SRC_DSCR 14 – 13 – 12 – 11 – 10 – 9 – 8 – 6 – 5 – 4 – 3 – 2 – 1 – 0 – FC • SRC_DSCR 0: Source address is updated when the descriptor is fetched from the memory. 1: Buffer Descriptor Fetch operation is disabled for the source. • DST_DSCR 0: Destination address is updated when the descriptor is fetched from the memory. 1: Buffer Descriptor Fetch operation is disabled for the destination. • FC This field defines which device controls the size of the buffer transfer, also referred as to the Flow Controller. FC Type of transfer Flow Controller 000 Memory-to-Memory DMA Controller 001 Memory-to-Peripheral DMA Controller 010 Peripheral-to-Memory DMA Controller 011 Peripheral-to-Peripheral DMA Controller • SRC_INCR SRC_INCR Type of addressing mode 00 INCREMENTING 10 FIXED • DST_INCR DST_INCR Type of addressing scheme 00 INCREMENTING 10 FIXED SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1039 • IEN If this bit is cleared, when the buffer transfer is completed, the BTC[x] flag is set in the EBCISR status register. This bit is active low. 1040 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 39.5.18 DMAC Channel x [x = 0..3] Configuration Register Name: DMAC_CFGx [x = 0..3] Addresses: 0x400B0050 [0], 0x400B0078 [1], 0x400B00A0 [2], 0x400B00C8 [3] Access: Read-write Reset: 0x0100000000 31 – 30 – 29 28 27 – 26 25 AHB_PROT 24 23 – 22 LOCK_IF_L 21 LOCK_B 20 LOCK_IF 19 – 18 – 17 – 16 SOD 15 – 14 – 13 DST_H2SEL 12 – 11 – 10 – 9 SRC_H2SEL 8 – 7 6 5 4 3 2 1 0 FIFOCFG DST_PER SRC_PER • SRC_PER Channel x Source Request is associated with peripheral identifier coded SRC_PER handshaking interface. • DST_PER Channel x Destination Request is associated with peripheral identifier coded DST_PER handshaking interface. • SRC_H2SEL 0: Software handshaking interface is used to trigger a transfer request. 1: Hardware handshaking interface is used to trigger a transfer request. • DST_H2SEL 0: Software handshaking interface is used to trigger a transfer request. 1: Hardware handshaking interface is used to trigger a transfer request. • SOD 0: STOP ON DONE disabled, the descriptor fetch operation ignores DONE Field of CTRLA register. 1: STOP ON DONE activated, the DMAC module is automatically disabled if DONE FIELD is set to 1. • LOCK_IF 0: Interface Lock capability is disabled 1: Interface Lock capability is enabled • LOCK_B 0: AHB Bus Locking capability is disabled. 1: AHB Bus Locking capability is enabled. • LOCK_IF_L 0: The Master Interface Arbiter is locked by the channel x for a chunk transfer. 1: The Master Interface Arbiter is locked by the channel x for a buffer transfer. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1041 • AHB_PROT AHB_PROT field provides additional information about a bus access and is primarily used to implement some level of protection. HPROT[3] HPROT[2] HPROT[1] HPROT[0] Description 1 Data access 0: User Access AHB_PROT[0] 1: Privileged Access 0: Not Bufferable AHB_PROT[1] 1: Bufferable 0: Not cacheable AHB_PROT[2] 1: Cacheable • FIFOCFG 1042 FIFOCFG FIFO request 00 The largest defined length AHB burst is performed on the destination AHB interface. 01 When half FIFO size is available/filled, a source/destination request is serviced. 10 When there is enough space/data available to perform a single AHB access, then the request is serviced. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 40. 12-bit Analog-to-Digital Converter (ADC12B) 40.1 Description The ADC12B is based on a Cyclic Pipeline 12-bit Analog-to-Digital Converter (ADC12B). It also integrates an 8-to-1 analog multiplexer, making possible the analog-to-digital conversions of 8 analog lines. The conversions extend from 0V to AD12BVREF. The ADC12B supports a 10-bit or 12-bit resolution mode, and conversion results are reported in a common register for all channels, as well as in a channel-dedicated register. Software trigger, external trigger on rising edge of the AD12BTRG pin, internal triggers from Timer Counter output(s) or PWM Event lines are configurable. The ADC12B also integrates a Sleep Mode and a conversion sequencer and connects with a PDC channel. These features reduce both power consumption and processor intervention. This ADC12B has a selectable single-ended or fully differential input and benefits from a 2-bit programmable gain. A whole set of reference voltage is generated internally from a single external reference voltage node that may be equal to the analog supply voltage. An external decoupling capacitance is required for noise filtering. A digital error correction circuit based on the multi-bit redundant signed digit (RSD) algorithm is employed in order to reduce INL and DNL errors. Finally, the user can configure ADC12B timings, such as Startup Time and Sample & Hold Time. 40.2 Block Diagram Figure 40-1. Analog-to-Digital Converter Block Diagram Timer Counter Channels ADC12B Trigger Selection AD12BTRG Control Logic ADC12B Interrupt NVIC AHB VDDANA PDC AD12BVREF AD12B0 Analog Inputs Peripheral Bridge PIO AD12B1 IN+ IN- OFFSET S/H PGA AD12Bn Cyclic Pipeline 12-bit Analog-to-Digital Converter User Interface APB GND 40.3 Signal Description Table 40-1. ADC12B Pin Description Pin Name Description AD12B0 - AD12B7 Analog input channels AD12BTRG External trigger SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1043 40.4 Product Dependencies 40.4.1 Power Management The ADC12B Controller is not continuously clocked. The programmer must first enable the ADC12B Controller clock in the Power Management Controller (PMC) before using the ADC12B Controller. However, if the application does not require ADC12B operations, the ADC12B Controller clock can be stopped when not needed and restarted when necessary. Configuring the ADC12B Controller does not require the ADC12B Controller clock to be enabled. 40.4.2 Interrupt Sources The ADC12B interrupt line is connected on one of the sources of the Nested Vectored Interrupt Controller (NVIC). Using the ADC12B interrupt requires the NVIC to be programmed first. Table 40-2. Peripheral IDs Instance ID ADC12B 26 40.4.3 Analog Inputs The analog input pins are multiplexed with PIO lines. The assignment of the ADC12B input is automatically done as soon as the corresponding channel is enabled by writing the register ADC12B_CHER. By default, after reset, the PIO line is configured as an input with its pull-up enabled and the ADC12B input is connected to the GND. 40.4.4 I/O Lines The AD12BTRG pin is shared with other peripheral functions through the PIO Controller. In this case, the PIO Controller needs to be set accordingly to assign the AD12BTRG pin to the ADC12B function. Table 40-3. I/O Lines Instance Signal I/O Line Peripheral ADC12B AD12BTRG PA2 B 40.4.5 Timer Triggers Timer Counters may or may not be used as hardware triggers depending on user requirements. Thus, some or all of the timer counters may be non-connected. 40.4.6 PWM Event Lines PWM Event Lines may or may not be used as hardware triggers depending on user requirements. 40.4.7 Conversion Performances For performance and electrical characteristics of the ADC12B, see the DC Characteristics section of the product datasheet. 1044 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 40.5 Functional Description 40.5.1 Analog-to-digital Conversion The ADC12B uses the ADC12B Clock to perform conversions. Converting a single analog value to 12-bit digital data requires Sample and Hold Clock cycles as defined in the SHTIM field of the “ADC12B Mode Register” on page 1054 and 10 ADC12B Clock cycles. The ADC12B Clock frequency is selected in the PRESCAL field of the Mode Register (ADC12B_MR). The ADC12B clock range is between MCK/2, if PRESCAL is 0, and MCK/128, if PRESCAL is set to 63 (0x3F). PRESCAL must be programmed in order to provide an ADC12B clock frequency according to the parameters given in the Electrical Characteristics section of the product datasheet. 40.5.2 Conversion Reference The conversion is performed on a full range between 0V and the reference voltage pin AD12BVREF Analog inputs between these voltages convert to values based on a linear conversion. 40.5.3 Conversion Resolution The ADC12B supports 10-bit or 12-bit resolution. The 10-bit selection is performed by setting the LOWRES bit in the ADC12B Mode Register (ADC12B_MR). By default, after a reset, the resolution is the highest and the DATA field in the data registers is fully used. By setting the LOWRES bit, the ADC12B switches in the lowest resolution and the conversion results can be read in the eight lowest significant bits of the data registers. The two highest bits of the DATA field in the corresponding ADC12B_CDR register and of the LDATA field in the ADC12B_LCDR register read 0. Moreover, when a PDC channel is connected to the ADC12B, 12-bit or 10-bit resolution sets the transfer request size to 16 bits. 40.5.4 Differential Inputs The ADC12B can be used either as a single ended ADC12B (DIFF bit equal to 0) or as a fully differential ADC12B (DIFF bit equal to 1) as shown in Figure 40-2. By default, after a reset, the ADC12B is in single ended mode. The same inputs are used in single ended or differential mode. In single ended mode, inputs are managed by an 8:1 channels analog multiplexer. In the fully differential mode, inputs are managed by a 4:1 channels analog multiplexer. See Table 40-4 and Table 40-5. Table 40-4. Input Pins and Channel Number in Single Ended Mode Input Pins Channel Number AD12B0 CH0 AD12B1 CH1 AD12B2 CH2 AD12B3 CH3 AD12B4 CH4 AD12B5 CH5 AD12B6 CH6 AD12B7 CH7 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1045 Table 40-5. Input Pins and Channel Number In Differential Mode Input Pins Channel Number AD12B0-AD12B1 CH0 AD12B2-AD12B3 CH2 AD12B4-AD125B CH4 AD12B6-AD12B7 CH6 40.5.5 Input Gain and Offset The ADC12B has a built in Programmable Gain Amplifier (PGA) and Programmable Offset. The Programmable Gain Amplifier can be set to gains of 1/2, 1, 2 and 4. The Programmable Gain Amplifier can be used either for single ended applications or for fully differential applications. The gain is configurable through the GAIN bit as shown in Table 40-6. Table 40-6. Gain of the Sample and Hold Unit: GAIN Bits and DIFF Bit. GAIN GAIN (DIFF = 0) GAIN (DIFF = 1) 00 1 0.5 01 1 1 10 2 2 11 4 2 To allow full range, analog offset of the ADC12B can be configured by the OFFSET bit. The Offset can only be changed in single ended mode. In fully differential mode the offset is always set to Vrefin/2. Table 40-7. Offset of the Sample and Hold Unit: OFFSET DIFF and Gain (G) OFFSET Bit OFFSET (DIFF = 0) 0 Vrefin/2G 1 Vrefin/2 OFFSET (DIFF = 1) Vrefin/2 1046 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 40-2. Analog Full Scale Ranges in Single Ended/Differential Applications Versus Gain and Offset single ended se0fd1=0 fully differential se0fd1=1 vrefin VIN+ VIN+ same as gain=1 gain=0.5 (½)vrefin (00) VIN- 0 vrefin (¾)vrefin VIN+ VIN+ gain=1 (½)vrefin VIN- (01) (¼)vrefin 0 vrefin offset=1 offset=0 (¾)vrefin (5/8)vrefin gain=2 (½)vrefin VIN+ (3/8)vrefin (10) VIN+ VIN+ VIN- (¼)vrefin 0 vrefin offset=1 gain=4 same as gain=2 offset=0 (5/8)vrefin VIN+ (½)vrefin (3/8)vrefin (11) VIN+ VIN+ VIN- (¼)vrefin (1/8)vrefin 0 40.5.6 Power Consumption Adjustment The power consumption of the ADC12B can be adjusted through a 2-bit bias control (IBCTL bit in ADC12B_ACR register) providing possibilities for smart optimization of power and effective resolution relative to the application speed request. Please refer to the Electrical Characteristics of the product datasheet for further details. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1047 40.5.7 Conversion Results When a conversion is completed, the resulting 12-bit digital value is stored in the Channel Data Register (ADC12B_CDR) of the current channel and in the ADC12B Last Converted Data Register (ADC12B_LCDR). The channel EOC bit in the Status Register (ADC12B_SR) is set and the DRDY bit is set. In the case of a connected PDC channel, DRDY rising triggers a data transfer request. In any case, either EOC and DRDY can trigger an interrupt. Reading one of the ADC12B_CDR registers clears the corresponding EOC bit. Reading ADC12B_LCDR clears the DRDY bit and the EOC bit corresponding to the last converted channel. Figure 40-3. EOCx and DRDY Flag Behavior Write the ADC_CR with START = 1 Read the ADC_CDRx Write the ADC_CR with START = 1 Read the ADC_LCDR CHx (ADC_CHSR) EOCx (ADC_SR) Conversion Time Conversion Time DRDY (ADC_SR) If the ADC12B_CDR is not read before further incoming data is converted, the corresponding Overrun Error (OVRE) flag is set in the Status Register (ADC12B_SR). Likewise, new data converted when DRDY is high sets the GOVRE bit (General Overrun Error) in ADC12B_SR. The OVRE and GOVRE flags are automatically cleared when ADC12B_SR is read. 1048 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 40-4. GOVRE and OVREx Flag Behavior Read ADC12B_SR Trigger CH0 (ADC12B_CHSR) CH1 (ADC12B_CHSR) ADC12B_LCDR Undefined Data ADC12B_CDR0 Undefined Data ADC12B_CDR1 EOC0 (ADC12B_SR) EOC1 (ADC12B_SR) Data CH1 Data CH0 Data CH0 Data CH0 Data CH0 Undefined Data Data CH1 Conversion Conversion Conversion Read ADC12B_CDR0 Read ADC12B_CDR1 GOVRE (ADC12B_SR) DRDY (ADC12B_SR) OVRE0 (ADC12B_SR) Warning: If the corresponding channel is disabled during a conversion or if it is disabled and then reenabled during a conversion, its associated data and its corresponding EOC and OVRE flags in ADC12B_SR are unpredictable. The ADC12B can be triggered externally by software or internally from the Timer Counter or PWM. 40.5.8 Conversion Triggers Conversions of the active analog channels are started with a software or a hardware trigger. The software trigger is provided by writing the Control Register (ADC12B_CR) with the START bit at 1. The hardware trigger can be one of the TIOA outputs of the Timer Counter channels, PWM Event lines or the external trigger input of the ADC12B (AD12BTRG). The hardware trigger is selected with the field TRGSEL in the Mode Register (ADC12B_MR). The selected hardware trigger is enabled with the TRGEN bit in the Mode Register (ADC12B_MR). If a hardware trigger is selected, the start of a conversion is triggered after a delay starting at each rising edge of the selected signal. Due to asynchronous handling, the delay may vary in a range of 2 MCK clock periods to 1 ADC12B clock period. trigger start delay SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1049 If one of the TIOA outputs is selected, the corresponding Timer Counter channel must be programmed in Waveform Mode. Only one start command is necessary to initiate a conversion sequence on all the channels. The ADC12B hardware logic automatically performs the conversions on the active channels, then waits for a new request. The Channel Enable (ADC12B_CHER) and Channel Disable (ADC12B_CHDR) Registers enable the analog channels to be enabled or disabled independently. If the ADC12B is used with a PDC, only the transfers of converted data from enabled channels are performed and the resulting data buffers should be interpreted accordingly. Warning: Enabling hardware triggers does not disable the software trigger functionality. Thus, if a hardware trigger is selected, the start of a conversion can be initiated either by the hardware or the software trigger. 40.5.9 Sleep Mode and Conversion Sequencer The ADC12B Sleep Mode maximizes power saving by automatically deactivating the ADC12B when it is not being used for conversions. Sleep Mode is selected by setting the SLEEP bit in the Mode Register ADC12B_MR. Two sleep Mode are selectable (OFFMODES): STANDBY Mode and OFF Mode. In Standby Mode, the ADC12B is powered off except voltage reference to allow fast startup. In OFF Mode the ADC12B is totally powered off. Table 40-8. Low Power Modes According SLEEP Bit and OFFMODES Bit. SLEEP Bit OFFMODES Bit Low Power Mode 0 _ Normal Mode 1 0 Standby Mode 1 1 Off Mode The SLEEP mode is automatically managed by a conversion sequencer, which can automatically process the conversions of all channels at lowest power consumption. When a start conversion request occurs, the ADC12B is automatically activated. As the analog cell requires a start-up time, the logic waits during this time and starts the conversion on the enabled channels. When all conversions are complete, the ADC12B is deactivated until the next trigger. Triggers occurring during the sequence are not taken into account. The conversion sequencer allows automatic processing with minimum processor intervention and optimized power consumption. Conversion sequences can be performed periodically using a Timer/Counter output or a PWM Event line. The periodic acquisition of several samples can be processed automatically without any intervention of the processor thanks to the PDC. The conversion sequencer can only be used if all ADC12B inputs have the same input configuration, e.g. same PGA gain, same input type (differential or single ended) and same input offset. If input have different configurations, sequencer can’t be used because PGA gain, input type and input offset can’t be changed. Note: The reference voltage pins always remain connected in normal mode as in sleep mode. 40.5.10 ADC12B Timings Each ADC12B has its own minimal Startup Time that is programmed through the field STARTUP in the Mode Register (ADC12B_MR). In the same way, a minimal Sample and Hold Time is necessary for the ADC12B to guarantee the best converted final value between the two channels selection. This time has to be programmed through the SHTIM bitfield in the Mode Register (ADC12B_MR). 1050 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Warning: No input buffer amplifier to isolate the source is included in the ADC12B. This must be taken into consideration to program a precise value in the SHTIM field. See the section, ADC12B Characteristics in the product datasheet. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1051 40.6 12-bit Analog-to-Digital Converter (ADC12B) User Interface Table 40-9. Register Mapping Offset Name Access Reset 0x00 Control Register ADC12B_CR Write-only – 0x04 Mode Register ADC12B_MR Read-write 0x00000000 0x08 Reserved – – – 0x0C Reserved – – – 0x10 Channel Enable Register ADC12B_CHER Write-only – 0x14 Channel Disable Register ADC12B_CHDR Write-only – 0x18 Channel Status Register ADC12B_CHSR Read-only 0x00000000 0x1C Status Register ADC12B_SR Read-only 0x000C0000 0x20 Last Converted Data Register ADC12B_LCDR Read-only 0x00000000 0x24 Interrupt Enable Register ADC12B_IER Write-only – 0x28 Interrupt Disable Register ADC12B_IDR Write-only – 0x2C Interrupt Mask Register ADC12B_IMR Read-only 0x00000000 0x30 Channel Data Register 0 ADC12B_CDR0 Read-only 0x00000000 0x34 Channel Data Register 1 ADC12B_CDR1 Read-only 0x00000000 ... ... ... ... ... 0x4C Channel Data Register 7 ADC12B_CDR7 Read-only 0x00000000 0x64 Analog Control Register ADC12B_ACR Read-write 0x00000000 0x68 Extended Mode Register ADC12B_EMR Read-write 0x00000000 – – – 0x50 - 0xFC 1052 Register Reserved SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 40.6.1 ADC12B Control Register Name: ADC12B_CR Address: 0x400A8000 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 – 1 START 0 SWRST • SWRST: Software Reset 0 = No effect. 1 = Resets the ADC12B simulating a hardware reset. • START: Start Conversion 0 = No effect. 1 = Begins analog-to-digital conversion. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1053 40.6.2 ADC12B Mode Register Name: ADC12B_MR Address: 0x400A8004 Access: Read-write 31 – 30 – 29 – 28 – 23 22 21 20 27 26 25 24 SHTIM 19 18 17 16 11 10 9 8 3 2 TRGSEL 1 0 TRGEN STARTUP 15 14 13 12 PRESCAL 7 – 6 – 5 SLEEP 4 LOWRES • TRGEN: Trigger Enable TRGEN Selected TRGEN 0 Hardware triggers are disabled. Starting a conversion is only possible by software. 1 Hardware trigger selected by TRGSEL field is enabled. • TRGSEL: Trigger Selection TRGSEL Selected TRGSEL 0 0 0 External trigger 0 0 1 TIO Output of the Timer Counter Channel 0 0 1 0 TIO Output of the Timer Counter Channel 1 0 1 1 TIO Output of the Timer Counter Channel 2 1 0 0 PWM Event Line 0 1 0 1 PWM Event Line 1 1 1 0 Reserved 1 1 1 Reserved • LOWRES: Resolution LOWRES Selected Resolution 0 12-bit resolution 1 10-bit resolution • SLEEP: Sleep Mode SLEEP 1054 Selected Mode 0 Normal Mode 1 Sleep Modes (see OFFMODES register) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 • PRESCAL: Prescaler Rate Selection ADC12BClock = MCK/( (PRESCAL+1) * 2 ) • STARTUP: Start Up Time Startup Time = (STARTUP+1) * 8/ADC12BClock • SHTIM: Sample & Hold Time Sample and Hold Time = SHTIM/ADC12BClock SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1055 40.6.3 ADC12B Channel Enable Register Name: ADC12B_CHER Address: 0x400A8010 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 CH7 6 CH6 5 CH5 4 CH4 3 CH3 2 CH2 1 CH1 0 CH0 • CHx: Channel x Enable 0 = No effect. 1 = Enables the corresponding channel. 1056 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 40.6.4 ADC12B Channel Disable Register Name: ADC12B_CHDR Address: 0x400A8014 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 CH7 6 CH6 5 CH5 4 CH4 3 CH3 2 CH2 1 CH1 0 CH0 • x: Channel x Disable 0 = No effect. 1 = Disables the corresponding channel. Warning: If the corresponding channel is disabled during a conversion or if it is disabled then reenabled during a conversion, its associated data and its corresponding EOC and OVRE flags in ADC12B_SR are unpredictable. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1057 40.6.5 ADC12B Channel Status Register Name: ADC12B_CHSR Address: 0x400A8018 Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 CH7 6 CH6 5 CH5 4 CH4 3 CH3 2 CH2 1 CH1 0 CH0 • CHx: Channel x Status 0 = Corresponding channel is disabled. 1 = Corresponding channel is enabled. 1058 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 40.6.6 ADC12B Analog Control Register Name: ADC12B_ACR Address: 0x400A8064 Access: Read-write 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 OFFSET 16 DIFF 15 – 14 – 13 – 12 – 11 – 10 – 9 7 – 6 – 5 – 4 – 3 – 2 – 1 8 IBCTL 0 GAIN • GAIN: Input Gain Gain of the sample and hold unit according to GAIN bits and DIFF bit GAIN GAIN (DIFFx = 0) GAIN (DIFF = 1) 00 1 0.5 01 1 1 10 2 2 11 4 2 • IBCTL: Bias Current Control Bias Current Control IBCTL Current 00 typ - 20% 01 typ 10 typ + 20% 11 typ + 40% • DIFF: Differential Mode 0 = Single Ended Mode 1 = Fully Differential Mode • OFFSET: Input OFFSET Offset of the sample and hold unit according to OFFSET bit, DIFF bit and Gain (G). OFFSET OFFSET (DIFF = 0) 0 Vrefin/2G 1 Vrefin/2 OFFSET (DIFF = 1) Vrefin/2 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1059 40.6.7 ADC12B Extended Mode Register Name: ADC12B_EMR Address: 0x400A8068 Access: Read-write 31 – 30 – 29 – 28 – 23 22 21 15 – 14 – 13 – 12 – 7 – 6 – 5 – 4 – 27 – 26 – 25 – 24 – 18 17 16 11 – 10 – 9 – 8 – 3 – 2 – 1 – 0 OFFMODES 20 19 OFF_MODE_STARTUP_TIME • OFFMODES: Off Mode if Sleep Bit (ADC12B_MR) = 1 0 = Standby Mode 1 = Off Mode • OFF_MODE_STARTUP_TIME: Startup Time Off Mode Startup Time = (OFF_MODE_STARTUP_TIME+1) * 8/ADC12BClock 1060 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 40.6.8 ADC12B Status Register Name: ADC12B_SR Address: 0x400A801C Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RXBUFF 18 ENDRX 17 GOVRE 16 DRDY 15 OVRE7 14 OVRE6 13 OVRE5 12 OVRE4 11 OVRE3 10 OVRE2 9 OVRE1 8 OVRE0 7 EOC7 6 EOC6 5 EOC5 4 EOC4 3 EOC3 2 EOC2 1 EOC1 0 EOC0 • EOCx: End of Conversion x 0 = Corresponding analog channel is disabled, or the conversion is not finished. 1 = Corresponding analog channel is enabled and conversion is complete. • OVREx: Overrun Error x 0 = No overrun error on the corresponding channel since the last read of ADC12B_SR. 1 = There has been an overrun error on the corresponding channel since the last read of ADC12B_SR. • DRDY: Data Ready 0 = No data has been converted since the last read of ADC12B_LCDR. 1 = At least one data has been converted and is available in ADC12B_LCDR. • GOVRE: General Overrun Error 0 = No General Overrun Error occurred since the last read of ADC12B_SR. 1 = At least one General Overrun Error has occurred since the last read of ADC12B_SR. • ENDRX: End of RX Buffer 0 = The Receive Counter Register has not reached 0 since the last write in ADC12B_RCR or ADC12B_RNCR. 1 = The Receive Counter Register has reached 0 since the last write in ADC12B_RCR or ADC12B_RNCR. • RXBUFF: RX Buffer Full 0 = ADC12B_RCR or ADC12B_RNCR have a value other than 0. 1 = Both ADC12B_RCR and ADC12B_RNCR have a value of 0. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1061 40.6.9 ADC12B Last Converted Data Register Name: ADC12B_LCDR Address: 0x400A8020 Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 10 9 8 7 6 5 4 1 0 LDATA 3 2 LDATA • LDATA: Last Data Converted The analog-to-digital conversion data is placed into this register at the end of a conversion and remains until a new conversion is completed. 1062 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 40.6.10 ADC12B Interrupt Enable Register Name: ADC12B_IER Address: 0x400A8024 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RXBUFF 18 ENDRX 17 GOVRE 16 DRDY 15 OVRE7 14 OVRE6 13 OVRE5 12 OVRE4 11 OVRE3 10 OVRE2 9 OVRE1 8 OVRE0 7 EOC7 6 EOC6 5 EOC5 4 EOC4 3 EOC3 2 EOC2 1 EOC1 0 EOC0 • EOCx: End of Conversion Interrupt Enable x • OVREx: Overrun Error Interrupt Enable x • DRDY: Data Ready Interrupt Enable • GOVRE: General Overrun Error Interrupt Enable • ENDRX: End of Receive Buffer Interrupt Enable • RXBUFF: Receive Buffer Full Interrupt Enable 0 = No effect. 1 = Enables the corresponding interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1063 40.6.11 ADC12B Interrupt Disable Register Name: ADC12B_IDR Address: 0x400A8028 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RXBUFF 18 ENDRX 17 GOVRE 16 DRDY 15 OVRE7 14 OVRE6 13 OVRE5 12 OVRE4 11 OVRE3 10 OVRE2 9 OVRE1 8 OVRE0 7 EOC7 6 EOC6 5 EOC5 4 EOC4 3 EOC3 2 EOC2 1 EOC1 0 EOC0 • EOCx: End of Conversion Interrupt Disable x • OVREx: Overrun Error Interrupt Disable x • DRDY: Data Ready Interrupt Disable • GOVRE: General Overrun Error Interrupt Disable • ENDRX: End of Receive Buffer Interrupt Disable • RXBUFF: Receive Buffer Full Interrupt Disable 0 = No effect. 1 = Disables the corresponding interrupt. 1064 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 40.6.12 ADC12B Interrupt Mask Register Name: ADC12B_IMR Address: 0x400A802C Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RXBUFF 18 ENDRX 17 GOVRE 16 DRDY 15 OVRE7 14 OVRE6 13 OVRE5 12 OVRE4 11 OVRE3 10 OVRE2 9 OVRE1 8 OVRE0 7 EOC7 6 EOC6 5 EOC5 4 EOC4 3 EOC3 2 EOC2 1 EOC1 0 EOC0 • EOCx: End of Conversion Interrupt Mask x • OVREx: Overrun Error Interrupt Mask x • DRDY: Data Ready Interrupt Mask • GOVRE: General Overrun Error Interrupt Mask • ENDRX: End of Receive Buffer Interrupt Mask • RXBUFF: Receive Buffer Full Interrupt Mask 0 = The corresponding interrupt is disabled. 1 = The corresponding interrupt is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1065 40.6.13 ADC12B Channel Data Register Name: ADC12B_CDRx Address: 0x400A8030 Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 10 9 8 7 6 5 4 1 0 DATA 3 2 DATA • DATA: Converted Data The analog-to-digital conversion data is placed into this register at the end of a conversion and remains until a new conversion is completed. The Convert Data Register (CDR) is only loaded if the corresponding analog channel is enabled. 1066 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41. Analog-to-Digital Converter (ADC) 41.1 Description The ADC is based on a Successive Approximation Register (SAR) 10-bit Analog-to-Digital Converter (ADC). It also integrates an 8-to-1 analog multiplexer, making possible the analog-to-digital conversions of 8 analog lines. The conversions extend from 0V to ADVREF. The ADC supports an 8-bit or 10-bit resolution mode, and conversion results are reported in a common register for all channels, as well as in a channel-dedicated register. Software trigger, external trigger on rising edge of the ADTRG pin or internal triggers from Timer Counter output(s) or PWM Event lines are configurable. The ADC also integrates a Sleep Mode and a conversion sequencer and connects with a PDC channel. These features reduce both power consumption and processor intervention. Finally, the user can configure ADC timings, such as Startup Time and Sample & Hold Time. 41.2 Block Diagram Figure 41-1. Analog-to-Digital Converter Block Diagram Timer Counter Channels PMC MCK ADC Controller Trigger Selection ADTRG Control Logic ADC Interrupt NVIC VDDANA ADC cell ADVREF System Bus AD0 Analog Inputs Multiplexed with I/O lines PDC PIO AD1 User Interface ADn Peripheral Bridge Successive Approximation Register Analog-to-Digital Converter APB GND 41.3 Signal Description Table 41-1. ADC Pin Description Pin Name Description AD0 - AD7 Analog input channels ADTRG External trigger SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1067 41.4 Product Dependencies 41.4.1 Power Management The MCK of the ADC Controller is not continuously clocked. The programmer must first enable the ADC Controller MCK in the Power Management Controller (PMC) before using the ADC Controller. However, if the application does not require ADC operations, the ADC Controller clock can be stopped when not needed and restarted when necessary. Configuring the ADC Controller does not require the ADC Controller clock to be enabled. 41.4.2 Interrupt Sources The ADC interrupt line is connected on one of the internal sources of the Advanced Interrupt Controller. Using the ADC interrupt requires the NVIC to be programmed first. Table 41-2. Peripheral IDs Instance ID ADC 27 41.4.3 Analog Inputs The analog input pins can be multiplexed with PIO lines. In this case, the assignment of the ADC input is automatically done as soon as the corresponding channel is enabled by writing the register ADC_CHER. By default, after reset, the PIO line is configured as input with its pull-up enabled and the ADC input is connected to the GND. 41.4.4 I/O Lines The pin ADTRG may be shared with other peripheral functions through the PIO Controller. In this case, the PIO Controller should be set accordingly to assign the pin ADTRG to the ADC function. 41.4.5 Timer Triggers Timer Counters may or may not be used as hardware triggers depending on user requirements. Thus, some or all of the timer counters may be non-connected. 41.4.6 PWM Event Lines PWM Event Lines may or may not be used as hardware triggers depending on user requirements. 41.4.7 Conversion Performances For performance and electrical characteristics of the ADC, see the DC Characteristics section. 1068 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41.5 Functional Description 41.5.1 Analog-to-digital Conversion The ADC uses the ADC Clock to perform conversions. Converting a single analog value to a 10-bit digital data requires Sample and Hold Clock cycles as defined in the field SHTIM of the “ADC Mode Register” on page 1075 and 10 ADC Clock cycles. The ADC Clock frequency is selected in the PRESCAL field of the Mode Register (ADC_MR). The ADC clock range is between MCK/2, if PRESCAL is 0, and MCK/128, if PRESCAL is set to 63 (0x3F). PRESCAL must be programmed in order to provide an ADC clock frequency according to the parameters given in the Product definition section. 41.5.2 Conversion Reference The conversion is performed on a full range between 0V and the reference voltage pin ADVREF Analog inputs between these voltages convert to values based on a linear conversion. 41.5.3 Conversion Resolution The ADC supports 8-bit or 10-bit resolutions. The 8-bit selection is performed by setting the bit LOWRES in the ADC Mode Register (ADC_MR). By default, after a reset, the resolution is the highest and the DATA field in the data registers is fully used. By setting the bit LOWRES, the ADC switches in the lowest resolution and the conversion results can be read in the eight lowest significant bits of the data registers. The two highest bits of the DATA field in the corresponding ADC_CDR register and of the LDATA field in the ADC_LCDR register read 0. Moreover, when a PDC channel is connected to the ADC, 10-bit resolution sets the transfer request sizes to 16-bit. Setting the bit LOWRES automatically switches to 8-bit data transfers. In this case, the destination buffers are optimized. 41.5.4 Conversion Results When a conversion is completed, the resulting 10-bit digital value is stored in the Channel Data Register (ADC_CDR) of the current channel and in the ADC Last Converted Data Register (ADC_LCDR). The channel EOC bit in the Status Register (ADC_SR) is set and the DRDY is set. In the case of a connected PDC channel, DRDY rising triggers a data transfer request. In any case, either EOC and DRDY can trigger an interrupt. Reading one of the ADC_CDR registers clears the corresponding EOC bit. Reading ADC_LCDR clears the DRDY bit and the EOC bit corresponding to the last converted channel. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1069 Figure 41-2. EOCx and DRDY Flag Behavior Write the ADC_CR with START = 1 Read the ADC_CDRx Write the ADC_CR with START = 1 Read the ADC_LCDR CHx (ADC_CHSR) EOCx (ADC_SR) Conversion Time Conversion Time DRDY (ADC_SR) If the ADC_CDR is not read before further incoming data is converted, the corresponding Overrun Error (OVRE) flag is set in the Status Register (ADC_SR). In the same way, new data converted when DRDY is high sets the bit GOVRE (General Overrun Error) in ADC_SR. The OVRE and GOVRE flags are automatically cleared when ADC_SR is read. 1070 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Figure 41-3. GOVRE and OVREx Flag Behavior Read ADC_SR ADTRG CH0 (ADC_CHSR) CH1 (ADC_CHSR) ADC_LCDR Undefined Data ADC_CDR0 Undefined Data ADC_CDR1 EOC0 (ADC_SR) EOC1 (ADC_SR) Data B Data A Data C Data A Data C Undefined Data Data B Conversion Conversion Conversion Read ADC_CDR0 Read ADC_CDR1 GOVRE (ADC_SR) DRDY (ADC_SR) OVRE0 (ADC_SR) Warning: If the corresponding channel is disabled during a conversion or if it is disabled and then reenabled during a conversion, its associated data and its corresponding EOC and OVRE flags in ADC_SR are unpredictable. 41.5.5 Conversion Triggers Conversions of the active analog channels are started with a software or a hardware trigger. The software trigger is provided by writing the Control Register (ADC_CR) with the bit START at 1. The hardware trigger can be one of the TIOA outputs of the Timer Counter channels, PWM Event lines or the external trigger input of the ADC (ADTRG). The hardware trigger is selected with the field TRGSEL in the Mode Register (ADC_MR). The selected hardware trigger is enabled with the bit TRGEN in the Mode Register (ADC_MR). If a hardware trigger is selected, the start of a conversion is triggered after a delay starting at each rising edge of the selected signal.Due to asynchronism handling, the delay may vary in a range of 2 MCK clock periods to 1 ADC clock period. trigger start delay SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1071 If one of the TIOA outputs is selected, the corresponding Timer Counter channel must be programmed in Waveform Mode. Only one start command is necessary to initiate a conversion sequence on all the channels. The ADC hardware logic automatically performs the conversions on the active channels, then waits for a new request. The Channel Enable (ADC_CHER) and Channel Disable (ADC_CHDR) Registers enable the analog channels to be enabled or disabled independently. If the ADC is used with a PDC, only the transfers of converted data from enabled channels are performed and the resulting data buffers should be interpreted accordingly. Warning: Enabling hardware triggers does not disable the software trigger functionality. Thus, if a hardware trigger is selected, the start of a conversion can be initiated either by the hardware or the software trigger. 41.5.6 Sleep Mode and Conversion Sequencer The ADC Sleep Mode maximizes power saving by automatically deactivating the ADC when it is not being used for conversions. Sleep Mode is selected by setting the bit SLEEP in the Mode Register ADC_MR. The SLEEP mode is automatically managed by a conversion sequencer, which can automatically process the conversions of all channels at lowest power consumption. When a start conversion request occurs, the ADC is automatically activated. As the analog cell requires a start-up time, the logic waits during this time and starts the conversion on the enabled channels. When all conversions are complete, the ADC is deactivated until the next trigger. Triggers occurring during the sequence are not taken into account. The conversion sequencer allows automatic processing with minimum processor intervention and optimized power consumption. Conversion sequences can be performed periodically using a Timer/Counter output or a PWM Event line. The periodic acquisition of several samples can be processed automatically without any intervention of the processor thanks to the PDC. Note: The reference voltage pins always remain connected in normal mode as in sleep mode. 41.5.7 ADC Timings Each ADC has its own minimal Startup Time that is programmed through the field STARTUP in the Mode Register ADC_MR. In the same way, a minimal Sample and Hold Time is necessary for the ADC to guarantee the best converted final value between two channels selection. This time has to be programmed through the bitfield SHTIM in the Mode Register ADC_MR. Warning: No input buffer amplifier to isolate the source is included in the ADC. This must be taken into consideration to program a precise value in the SHTIM field. See the section, ADC Characteristics in the product datasheet. 1072 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41.6 Analog-to-Digital Converter (ADC) User Interface Table 41-3. Register Mapping Offset Register Name Access Reset 0x00 Control Register ADC_CR Write-only – 0x04 Mode Register ADC_MR Read-write 0x00000000 0x08 Reserved – – – 0x0C Reserved – – – 0x10 Channel Enable Register ADC_CHER Write-only – 0x14 Channel Disable Register ADC_CHDR Write-only – 0x18 Channel Status Register ADC_CHSR Read-only 0x00000000 0x1C Status Register ADC_SR Read-only 0x000C0000 0x20 Last Converted Data Register ADC_LCDR Read-only 0x00000000 0x24 Interrupt Enable Register ADC_IER Write-only – 0x28 Interrupt Disable Register ADC_IDR Write-only – 0x2C Interrupt Mask Register ADC_IMR Read-only 0x00000000 0x30 Channel Data Register 0 ADC_CDR0 Read-only 0x00000000 0x34 Channel Data Register 1 ADC_CDR1 Read-only 0x00000000 ... ... ... ADC_CDR7 Read-only 0x00000000 – – – ... 0x4C 0x50 - 0xFC ... Channel Data Register 7 Reserved SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1073 41.6.1 ADC Control Register Name: ADC_CR Address: 0x400AC000 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 – 1 START 0 SWRST • SWRST: Software Reset 0 = No effect. 1 = Resets the ADC simulating a hardware reset. • START: Start Conversion 0 = No effect. 1 = Begins analog-to-digital conversion. 1074 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41.6.2 ADC Mode Register Name: ADC_MR Address: 0x400AC004 Access: Read-write 31 – 30 – 29 – 28 – 27 23 – 22 21 20 19 STARTUP 15 14 13 12 26 25 24 18 17 16 11 10 9 8 3 2 TRGSEL 1 0 TRGEN SHTIM PRESCAL 7 – 6 – 5 SLEEP 4 LOWRES • TRGEN: Trigger Enable TRGEN Selected TRGEN 0 Hardware triggers are disabled. Starting a conversion is only possible by software. 1 Hardware trigger selected by TRGSEL field is enabled. • TRGSEL: Trigger Selection TRGSEL Selected TRGSEL 0 0 0 TIO Output of the Timer Counter Channel 0 0 0 1 TIO Output of the Timer Counter Channel 1 0 1 0 TIO Output of the Timer Counter Channel 2 0 1 1 PWM Event Line 0 1 0 0 PWM Event Line 1 1 0 1 Reserved 1 1 0 External trigger 1 1 1 Reserved • LOWRES: Resolution LOWRES Selected Resolution 0 10-bit resolution 1 8-bit resolution • SLEEP: Sleep Mode SLEEP Selected Mode 0 Normal Mode 1 Sleep Mode • PRESCAL: Prescaler Rate Selection ADCClock = MCK / ( (PRESCAL+1) * 2 ) SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1075 • STARTUP: Start Up Time Startup Time = (STARTUP+1) * 8 / ADCClock • SHTIM: Sample & Hold Time Sample & Hold Time = SHTIM/ADCClock 1076 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41.6.3 ADC Channel Enable Register Name: ADC_CHER Address: 0x400AC010 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 CH7 6 CH6 5 CH5 4 CH4 3 CH3 2 CH2 1 CH1 0 CH0 • CHx: Channel x Enable 0 = No effect. 1 = Enables the corresponding channel. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1077 41.6.4 ADC Channel Disable Register Name: ADC_CHDR Address: 0x400AC014 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 CH7 6 CH6 5 CH5 4 CH4 3 CH3 2 CH2 1 CH1 0 CH0 • CHx: Channel x Disable 0 = No effect. 1 = Disables the corresponding channel. Warning: If the corresponding channel is disabled during a conversion or if it is disabled then reenabled during a conversion, its associated data and its corresponding EOC and OVRE flags in ADC_SR are unpredictable. 1078 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41.6.5 ADC Channel Status Register Name: ADC_CHSR Address: 0x400AC018 Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 – 8 – 7 CH7 6 CH6 5 CH5 4 CH4 3 CH3 2 CH2 1 CH1 0 CH0 • CHx: Channel x Status 0 = Corresponding channel is disabled. 1 = Corresponding channel is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1079 41.6.6 ADC Status Register Name: ADC_SR Address: 0x400AC01C Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RXBUFF 18 ENDRX 17 GOVRE 16 DRDY 15 OVRE7 14 OVRE6 13 OVRE5 12 OVRE4 11 OVRE3 10 OVRE2 9 OVRE1 8 OVRE0 7 EOC7 6 EOC6 5 EOC5 4 EOC4 3 EOC3 2 EOC2 1 EOC1 0 EOC0 • EOCx: End of Conversion x 0 = Corresponding analog channel is disabled, or the conversion is not finished. 1 = Corresponding analog channel is enabled and conversion is complete. • OVREx: Overrun Error x 0 = No overrun error on the corresponding channel since the last read of ADC_SR. 1 = There has been an overrun error on the corresponding channel since the last read of ADC_SR. • DRDY: Data Ready 0 = No data has been converted since the last read of ADC_LCDR. 1 = At least one data has been converted and is available in ADC_LCDR. • GOVRE: General Overrun Error 0 = No General Overrun Error occurred since the last read of ADC_SR. 1 = At least one General Overrun Error has occurred since the last read of ADC_SR. • ENDRX: End of RX Buffer 0 = The Receive Counter Register has not reached 0 since the last write in ADC_RCR or ADC_RNCR. 1 = The Receive Counter Register has reached 0 since the last write in ADC_RCR or ADC_RNCR. • RXBUFF: RX Buffer Full 0 = ADC_RCR or ADC_RNCR have a value other than 0. 1 = Both ADC_RCR and ADC_RNCR have a value of 0. 1080 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41.6.7 ADC Last Converted Data Register Name: ADC_LCDR Address: 0x400AC020 Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 7 6 5 4 3 2 1 8 LDATA 0 LDATA • LDATA: Last Data Converted The analog-to-digital conversion data is placed into this register at the end of a conversion and remains until a new conversion is completed. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1081 41.6.8 ADC Interrupt Enable Register Name: ADC_IER Address: 0x400AC024 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RXBUFF 18 ENDRX 17 GOVRE 16 DRDY 15 OVRE7 14 OVRE6 13 OVRE5 12 OVRE4 11 OVRE3 10 OVRE2 9 OVRE1 8 OVRE0 7 EOC7 6 EOC6 5 EOC5 4 EOC4 3 EOC3 2 EOC2 1 EOC1 0 EOC0 • EOCx: End of Conversion Interrupt Enable x • OVREx: Overrun Error Interrupt Enable x • DRDY: Data Ready Interrupt Enable • GOVRE: General Overrun Error Interrupt Enable • ENDRX: End of Receive Buffer Interrupt Enable • RXBUFF: Receive Buffer Full Interrupt Enable 0 = No effect. 1 = Enables the corresponding interrupt. 1082 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41.6.9 ADC Interrupt Disable Register Name: ADC_IDR Address: 0x400AC028 Access: Write-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RXBUFF 18 ENDRX 17 GOVRE 16 DRDY 15 OVRE7 14 OVRE6 13 OVRE5 12 OVRE4 11 OVRE3 10 OVRE2 9 OVRE1 8 OVRE0 7 EOC7 6 EOC6 5 EOC5 4 EOC4 3 EOC3 2 EOC2 1 EOC1 0 EOC0 • EOCx: End of Conversion Interrupt Disable x • OVREx: Overrun Error Interrupt Disable x • DRDY: Data Ready Interrupt Disable • GOVRE: General Overrun Error Interrupt Disable • ENDRX: End of Receive Buffer Interrupt Disable • RXBUFF: Receive Buffer Full Interrupt Disable 0 = No effect. 1 = Disables the corresponding interrupt. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1083 41.6.10 ADC Interrupt Mask Register Name: ADC_IMR Address: 0x400AC02C Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 RXBUFF 18 ENDRX 17 GOVRE 16 DRDY 15 OVRE7 14 OVRE6 13 OVRE5 12 OVRE4 11 OVRE3 10 OVRE2 9 OVRE1 8 OVRE0 7 EOC7 6 EOC6 5 EOC5 4 EOC4 3 EOC3 2 EOC2 1 EOC1 0 EOC0 • EOCx: End of Conversion Interrupt Mask x • OVREx: Overrun Error Interrupt Mask x • DRDY: Data Ready Interrupt Mask • GOVRE: General Overrun Error Interrupt Mask • ENDRX: End of Receive Buffer Interrupt Mask • RXBUFF: Receive Buffer Full Interrupt Mask 0 = The corresponding interrupt is disabled. 1 = The corresponding interrupt is enabled. 1084 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 41.6.11 ADC Channel Data Register Name: ADC_CDRx Address: 0x400AC030 Access: Read-only 31 – 30 – 29 – 28 – 27 – 26 – 25 – 24 – 23 – 22 – 21 – 20 – 19 – 18 – 17 – 16 – 15 – 14 – 13 – 12 – 11 – 10 – 9 7 6 5 4 3 2 1 8 DATA 0 DATA • DATA: Converted Data The analog-to-digital conversion data is placed into this register at the end of a conversion and remains until a new conversion is completed. The Convert Data Register (CDR) is only loaded if the corresponding analog channel is enabled. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1085 42. Electrical Characteristics 42.1 Absolute Maximum Ratings Table 42-1. Absolute Maximum Ratings* Operating Temperature (Industrial)....................-40°C to + 85°C *NOTICE: Storage Temperature.......................................-60°C to + 150°C Voltage on Input Pins with Respect to Ground.......................................-0.3V to + 4.0V Maximum Operating Voltage (VDDCORE) .......................................................................2.0V Maximum Operating Voltage (VDDIO) ..............................................................................4.0V Total DC Output Current on all I/O lines 100-lead LQFP................................................................100 mA 144-lead LQFP ...............................................................130 mA 100-ball TFBGA .............................................................100 mA 144-ball LFBGA .............................................................130 mA 1086 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. 42.2 DC Characteristics The following characteristics are applicable to the operating temperature range: TA = -40°C to 85°C, unless otherwise specified. Table 42-2. DC Characteristics Symbol Parameter Conditions Min Typ Max Unit VDDCORE DC Supply Core 1.62 1.8 1.95 V VDDIO DC Supply I/Os 1.62 3.3 3.6 V VDDBU Backup I/O Lines Power Supply 1.62 3.6 V VDDUTMI USB UTMI+ Interface Power Supply 3.0 3.6 V VDDPLL PLL A, UPLL and Main Oscillator Supply 1.62 1.95 V VDDANA ADC Analog Power Supply (1) (1) V VIL Input Low-level Voltage PIOA/B/C[0–31] -0.3 0.3 × VDDIO V VIH Input High-level Voltage PIOA/B/C[0–31] 0.7 × VDDIO VDDIO + 0.3V V VOH Output High-level Voltage PIOA/B/C[0–31] IOH ~ 0 IOH > 0 (See IOH characteristics in this table) VDDIO - 0.2V VDDIO - 0.4V VOL Output Low-level Voltage PIOA/B/C[0–31] IOH ~ 0 IOH > 0 (See IOL characteristics in this table) VHys IOH Hysteresis Voltage Source Current V 0.2 0.4 V PIOA/B/C[0–31] except PIOA[14], PB[9–16], PB[25–PB31] and PC[20–27] 150 500 mV ERASE, TST, FWUP, JTAGSEL 230 700 mV 1.62V < VDDIO < 1.95V; VOH = VDDIO - 0.4V - PA3 (SPCK), PA15 (MCCK) pins - Other pins(2) -8 -3 3.0V < VDDIO < 3.6V; VOH = VDDIO - 0.4V - PA3 (SPCK), PA15 (MCCK) pins - Other pins(2) -15 -3 1.62V < VDDIO < 3.6V; VOH = VDDIO - 0.4V - NRST, TDO -2 Relaxed Mode: 3.0V < VDDIO < 3.6V; VOH = 2.2V - PA3 (SPCK), PA15 (MCCK) pins - Other pins(2) -24 -9 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 mA 1087 Table 42-2. Symbol DC Characteristics (Continued) Parameter Sink Current IOL Conditions Min Typ 1.62V < VDDIO < 1.95V; VOL = 0.4V - PA3 (SPCK), PA15 (MCCK) pins - Other pins(2) 8 4 3.0V < VDDIO < 3.6V; VOL = 0.4V - PA3 (SPCK), PA15 (MCCK) pins - Other pins(2) 9 6 1.62V < VDDIO < 3.6V; VOL = 0.4V - NRST, TDO IIL Leakage Current Input High IIH Leakage Current Pull-up Resistor RPULLUP RPULLDOWN Pull-down Resistor RODT Notes: 1088 1. 2. 3. 4. Unit mA 2 Relaxed Mode: 3.0V < VDDIO < 3.6V; VOL = 0.6V - PA3 (SPCK), PA15 (MCCK) pins - Other pins(2) Input Low Max 14 9 VDDIO powered pins(3) No pull-up or pull-down; VIN = GND; VDDIO Max. (Typ: TA = 25°C, Max: TA = 85°C) 5 VDDBU powered pins(4) No pull-up or pull-down; VIN = GND; VDDBU Max. (Typ: TA = 25°C, Max: TA = 85°C) VDDIO powered pins(3) No pull-up or pull-down; VIN = VDD; VDDIO Max. (Typ: TA = 25°C, Max: TA = 85°C) 2 VDDBU powered pins(4) No pull-up or pull-down; VIN = VDD; VDDBU Max. (Typ: TA = 25°C, Max: TA = 85°C) nA 1 µA 18 nA 1 µA 150 kΩ PA0–PA31, PB0–PB31, PC0–PC31 50 NRSTB 10 20 kΩ TST, ERASE, JTAGSEL 10 20 kΩ 43 Ω On-die Series Termination PA0–PA31, PB0–PB31, PC0–PC31 28 Resistor Refer to Section 42.7 “12-bit ADC Characteristics” and Section 42.9 “AC Characteristics” PA[0–2], PA[4–14], PA[16–31]; PB[0–31]; PC[0–31] PA[0–31], PB[0–31], PC[0–31] FWUP, JTAGSEL, NRSTB, ERASE, TST SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 100 30 36 Table 42-3. 1.8V Voltage Regulator Characteristics Symbol Parameter VDDIN DC Input Voltage Range VDDOUT DC Output Voltage VO(accuracy) Output Voltage Accuracy ILOAD Maximum DC Output Current ILOAD-START Maximum Peak Current during startup(3) (3) 300 mA VDROPOUT Dropout Voltage VDDIN = 1.8V ILOAD = 60 mA 150 mV VLINE Line Regulation VDDIN 2.7–3.6 V ILOAD MAX 20 50 mV VLINE-TR Transient Line regulation VDDIN 2.7–3.6 V tr = tf = 5 µs ILOAD Max CDOUT = 4.7µF 50 100 mV VLOAD Load Regulation VDDIN ≥ 2.2V ILOAD = 10% to 90% MAX 20 50 mV Transient Load Regulation VDDIN ≥ 2.2V ILOAD = 10% to 90% MAX tr = tf = 5 µs CDOUT = 4.7 µF 50 100 mV Normal Mode @ ILOAD = 0 mA 7 10 700 1200 VLOAD-TR IQ Quiescent Current Conditions Min Typ Max Unit 1.8 3.3 3.6 V Normal Mode 1.8 Standby Mode 0 V ILOAD = 0.5–150 mA -3 3 VDDIN > 2.2V 150 VDDIN ≤ 2.2V 60 mA Normal Mode @ ILOAD = 150 mA Standby Mode CDIN CDOUT ton Notes: Input Decoupling Capacitor µA 1 (1) 10 µF (2) 4.7 µF Output Decoupling Capacitor ESR Turn on Time % 0.5 10 Ω CDOUT = 4.7 µF, VDDOUT reaches VT+ (core power brownout detector supply rising threshold) 120 250 µs CDOUT = 4.7 µF, VDDOUT reaches 1.8V (± 3%) 200 400 µs 1. A 10 µF or higher ceramic capacitor must be connected between VDDIN and the closest GND pin of the device. This large decoupling capacitor is mandatory to reduce startup current, improving transient response and noise rejection. 2. To ensure stability, an external 4.7µF output capacitor, CDOUT must be connected between the VDDOUT and the closest GND pin of the device. The ESR (Equivalent Series Resistance) of the capacitor must be in the range 0.5 to 10 Ω. Solid tantalum, and multilayer ceramic capacitors are all suitable as output capacitor. A 100 nF bypass capacitor between VDDOUT and the closest GND pin of the device decreases output noise and improves the load transient response. 3. Defined as the current needed to charge external bypass/decoupling capacitor network. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1089 Table 42-4. Symbol Core Power Supply Brownout Detector Characteristics Parameter Conditions (1) Typ Max Unit 1.52 1.55 1.58 V 25 38 mV VT- Supply Falling Threshold Vhys- Hysteresis VT- VT+ Supply Rising Threshold 1.35 1.50 1.62 V tRST Reset Period 100 – 350 µs Vhys+ Hysteresis VT+ 100 250 mV Brownout Detector enabled IDDON td- VT- Detection Propagation Time td+ VT+ Detection Propagation Time tSTART Startup Time Note: 18 µA Current Consumption on VDDCORE IDDOFF 1. Figure 42-1. Brownout Detector disabled 200 nA VDDCORE = VT+ to (VT- - 100mV) 200 ns 200 350 µs 100 200 µs 100 From disabled state to enabled state The product is guaranteed to be functional at VTCore Brownout Output Waveform VDDCORE VT+ VTt BOD OUTPUT td- td+ t 1090 Min SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 42-5. VDDUTMI Supply Monitor Symbol Parameter Conditions Min VT Supply Monitor Threshold 16 selectable steps of 100mV VT(accuracy) Threshold Level Accuracy Vhys Hysteresis Voltage IDDON Figure 42-2. Unit 1.9 3.4 V -1.5 +1.5 % 20 30 mV 18 28 Current Consumption on VDDCORE µA Disabled IDDOFF tSTART Max Enabled Typ Startup Time 1 From disabled state to enabled state 140 µs VDDUTMI Supply Monitor VDDIO VT + Vhys VT Reset Table 42-6. Backup Power Supply Zero-Power-on Reset Characteristics Symbol Parameter Conditions Min Typ Max Unit VT+ Threshold Voltage Rising At startup 1.50 1.55 1.60 V VT- Threshold Voltage Falling 1.40 1.45 1.50 V tRST Reset Period 40 90 150 µs Figure 42-3. Zero-Power-on Reset Characteristics VDDIO VT+ VT- Reset SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1091 Table 42-7. Symbol DC Flash Characteristics Parameter IDD(standby) Standby Current Conditions Typ Max @ 25°C onto VDDCORE = 1.8V 100 kHz (VDDIO - 0.4V) ÷ 3mA 1000ns ÷ Cb 300ns ÷ Cb Ω fTWCK ≤ 100 kHz (3) – µs fTWCK > 100 kHz (3) – µs fTWCK ≤ 100 kHz (4) – µs fTWCK > 100 kHz (4) – µs fTWCK ≤ 100 kHz tHIGH – µs fTWCK > 100 kHz tHIGH – µs fTWCK ≤ 100 kHz tHIGH – µs fTWCK > 100 kHz tHIGH – µs fTWCK ≤ 100 kHz 0 3 × tCPMCK µs fTWCK > 100 kHz 0 3 × tCPMCK µs fTWCK ≤ 100 kHz tLOW - 3 × tCPMCK – ns fTWCK > 100 kHz tLOW - 3 × tCPMCK – ns fTWCK ≤ 100 kHz tHIGH – µs fTWCK > 100 kHz tHIGH – µs fTWCK ≤ 100 kHz tLOW – µs fTWCK > 100 kHz tLOW – µs Required only for fTWCK > 100 kHz Cb = capacitance of one bus line in pF. Per I2C Standard compatibility, Cb Max = 400 pF The TWCK low period is defined as follows: tLOW = ((CLDIV × 2CKDIV) + 4) × tMCK The TWCK high period is defined as follows: tHIGH = ((CHDIV × 2CKDIV) + 4) × tMCK tCPMCK = MCK bus period SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1129 Figure 42-32. Two-wire Serial Bus Timing tHIGH tfo tLOW tr tLOW TWCK tsu(start) th(start) th(data) tsu(data) tsu(stop) TWD tBUF 42.9.8 Embedded Flash Characteristics The maximum operating frequency given in Table 42-55 is limited by the Embedded Flash access time when the processor is fetching code out of it. The table provides the device maximum operating frequency defined by the value of field FWS of the EEFC_FMR. This field defines the number of wait states required to access the Embedded Flash Memory. Note: The embedded flash is fully tested during production test, the flash contents is not set to a known state prior to shipment. Therefore, the flash contents should be erased prior to programming an application. Table 42-55. Embedded Flash Wait State - VDDCORE 1.62V/1.80V Maximum Operating Frequency (MHz) EEFC_FMR.FWS Read Operations VDDCORE 1.62V VDDCORE 1.80V 0 1 cycle 24 27 1 2 cycles 40 47 2 3 cycles 72 84 3 4 cycles 84 96 Table 42-56. AC Flash Characteristics Parameter Conditions Min Typ Max Unit Per page including auto-erase 4.6 ms Per page without auto-erase 2.3 ms 11.5 ms Program Cycle Time Full Chip Erase Data Retention 10 Not Powered or Powered 10 Write/Erase cycles @ 25°C 30K Endurance cycles Write/Erase cycles @ 85°C 1130 years SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 10K 43. Mechanical Characteristics 43.1 100-lead LQFP Package Figure 43-1. 100-lead LQFP Package Drawing Table 43-1. Device and 100-lead LQFP Package Maximum Weight SAM3UE4/2/1 Table 43-2. 800 100-lead LQFP Package Reference JEDEC Drawing Reference MS-026 JESD97 Classification e3 Table 43-3. mg 100-lead LQFP Package Characteristics Moisture Sensitivity Level 3 This package respects the recommendations of the NEMI User Group. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1131 43.2 100-ball TFBGA Package Figure 43-2. 100-ball TFBGA Package Drawing 0.0433 Table 43-4. 100-ball TFBGA Soldering Information (Substrate Level) Ball Land 0.45 mm Soldering Mask Opening 0.35 mm Table 43-5. 100-ball TFBGA Device Maximum Weight 141 Table 43-6. mg 100-ball TFBGA Package Characteristics Moisture Sensitivity Level Table 43-7. 3 100-ball TFBGA Package Reference JEDEC Drawing Reference MO-275-DDAC-1 JESD97 Classification e8 This package respects the recommendations of the NEMI User Group. 1132 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 43.3 144-lead LQFP Package Figure 43-3. Notes: 1. 2. 3. 4. 5. 6. Table 43-8. 144-lead LQFP Package Drawing This drawing is for general information only; refer to JEDEe Drawing MS-026 for additional information. The top package body size may be smaller than the bottom package size by as much as 0.15 mm. Dimensions D1 and E1 do not include mold protrusions. Allowable protrusion is 0.25 mm per side. D1 and E1 are maximum plastic body size dimensions including mold mismatch. b dimension by more than 0.08 mm. Dambar cannot be located on the lower radius or the foot. Minimum space between protrusion and an adjacent lead is 0.07 mm for 0.4 and 0.5 mm pitch packages. These dimensions apply to the flat section of the lead between 0.10 mm and 0.25 mm from the lead tip. A1 is defined as the distance from the seating place to the lowest point on the package body. 144-lead LQFP Device Maximum Weight 1400 Table 43-9. mg 144-lead LQFP Package Characteristics Moisture Sensitivity Level Table 43-10. 3 144-lead LQFP Package Reference JEDEC Drawing Reference MS-026 JESD97 Classification e3 This package respects the recommendations of the NEMI User Group. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1133 43.4 144-ball LFBGA Package Figure 43-4. 144-ball LFBGA Package Drawing All dimensions are in mm. Table 43-11. 144-ball LFBGA Soldering Information (Substrate Level) Ball Land 0.380 mm Soldering Mask Opening 0.280 mm Table 43-12. Device and 144-ball LFBGA Package Maximum Weight 300 Table 43-13. mg 144-ball LFBGA Package Characteristics Moisture Sensitivity Level Table 43-14. 3 144-ball LFBGA Package Reference JEDEC Drawing Reference none JESD97 Classification e1 This package respects the recommendations of the NEMI User Group. 1134 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 43.5 Soldering Profile Table 43-15 gives the recommended soldering profile from J-STD-020C. Table 43-15. Soldering Profile Profile Feature Green Package Average Ramp-up Rate (217°C to Peak) 3°C/sec. max. Preheat Temperature 175°C ±25°C 180 sec. max. Temperature Maintained Above 217°C 60 sec. to 150 sec. Time within 5°C of Actual Peak Temperature 20 sec. to 40 sec. Peak Temperature Range 260°C Ramp-down Rate 6°C/sec. max. Time 25°C to Peak Temperature 8 min. max. Note: The package is certified to be backward compatible with Pb/Sn soldering profile. A maximum of three reflow passes is allowed per component. 43.6 Packaging Resources Land Pattern Definition. Refer to the following IPC Standards:  IPC-7351A and IPC-782 (Generic Requirements for Surface Mount Design and Land Pattern Standards) http://landpatterns.ipc.org/default.asp  Atmel Green and RoHS Policy and Package Material Declaration Data Sheet available on www.atmel.com SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1135 44. Marking All devices are marked with the Atmel logo and the ordering code. Additional marking is as follows: YYWW V XXXXXXXXX ARM where 1136  “YY”: manufactory year  “WW”: manufactory week  “V”: revision  “XXXXXXXXX”: lot number SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 45. Ordering Information Table 45-1. SAM3U Ordering Information Operating Temperature Range Ordering Code MRL Flash (Kbytes) Package ATSAM3U4EA-AU A 256 LQFP144 Industrial -40°C to 85°C ATSAM3U4EA-CU A 256 LFBGA 144 Industrial -40°C to 85°C ATSAM3U4CA-AU A 256 LQFP 100 Industrial -40°C to 85°C ATSAM3U4CA-CU A 256 TFBGA100 Industrial -40°C to 85°C ATSAM3U2EA-AU A 128 LQFP144 Industrial -40°C to 85°C ATSAM3U2EA-CU A 128 LFBGA144 Industrial -40°C to 85°C ATSAM3U2CA-AU A 128 LQFP100 Industrial -40°C to 85°C ATSAM3U2CA-CU A 128 TFBGA100 Industrial -40°C to 85°C ATSAM3U1EA-AU A 64 LQFP144 Industrial -40°C to 85°C ATSAM3U1EA-CU A 64 LFBGA144 Industrial -40°C to 85°C ATSAM3U1CA-AU A 64 LQFP100 Industrial -40°C to 85°C ATSAM3U1CA-CU A 64 TFBGA100 Industrial -40°C to 85°C ATSAM3U1EB-AU B 64 LQFP144 Industrial -40°C to 85°C ATSAM3U1EB-CU B 64 LFBGA144 Industrial -40°C to 85°C ATSAM3U1CB-AU B 64 LQFP100 Industrial -40°C to 85°C ATSAM3U1CB-CU B 64 TFBGA100 Industrial -40°C to 85°C SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1137 46. SAM3U Series Errata 46.1 SAM3U Errata - Rev. A Parts Revision A parts Chip IDs are as follows: SAM3U4C (Rev A) 0x28000961 SAM3U2C (Rev A) 0x280A0761 SAM3U1C (Rev A) 0x28090561 SAM3U4E (Rev A) 0x28100961 SAM3U2E (Rev A) 0x281A0761 SAM3U1E (Rev A) 0x28190561 46.1.1 Flash 46.1.1.1 Flash: Issue Running at Frequency Lower than 5 MHz When the system clock (MCK) is lower than 5 MHz with two Wait States (WS) programmed in the EEFC Flash Mode Register (EEFC_FMR), the Cortex fetches erroneous instructions. Problem Fix/Workaround Do not use two WS when running at a frequency lower than 5 MHz. 46.1.1.2 Flash: Read Flash in 64-bit Mode Higher than expected power consumption can be seen when reading Flash in 64-bit mode. Problem Fix/Workaround Use 128-bit mode instead. 46.1.1.3 Flash: Flash Programming When writing data into the Flash memory plane (either through the EEFC, using the IAP function, or FFPI), the data may not be correctly written (i.e., the data written is not the one expected). Problem Fix/Workaround Set the number of Wait States (WS) to 6 (FWS = 6) during the programming. 46.1.1.4 Flash: Fetching Error after Reading the Unique Identifier After reading the Unique Identifier (or using the STUI/SPUI command), the processor may fetch wrong instructions. It depends on the code and on the region of the code. Problem Fix/Workaround In order to avoid this problem, follow the steps below: 1. Set bit 16 of EEFC_FMR to 1 2. Send the Start Read Unique Identifier command (STUI) by writing the EEFC Flash Command Register (EEFC_FCR) with the STUI command. 3. Wait for the FRDY bit to fall 4. Read the Unique ID (and next bits if required) 5. Send the Stop Read Unique Identifier command (SPUI) by writing the EEFC_FCR with the SPUI command. 6. Wait for the FRDY bit to rise 7. Clear bit 16 of EEFC_FMR Note: 1138 During the sequence, the software cannot run out of Flash (so needs to run out of SRAM). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 46.1.2 12-bit Analog-to-Digital Converter (ADC12B) 46.1.2.1 ADC12B: Current Consumption in Backup Mode on VDDANA In Backup mode, the current consumption on VDDANA is around 1.0 mA instead of 0.1 µA Problem Fix/Workaround Four workarounds are possible: 1. Do not supply VDDANA and VDDIO in Backup mode using an external switch managed by SHDN pin. 2. Do not supply VDDANA in Backup mode using an external switch managed by the SHDN and set all PIOs with ADC inputs (PA22, PA30, PB3–PB8, PC15–PC18, PC28–C21) at low level (either externally or by software). 3. Do not supply VDDANA in Backup mode using an external switch managed by any PIO and set all PIOs with ADC inputs (PA22, PA30, PB3–PB8, PC15–PC18, PC28–C21) at low level (either externally or by software). Since the PIO state is preserved when in backup mode, any free PIO line can be used to switch off the external switch by driving the PIO line at low level (PIO is input, pull-up enabled after backup reset). 4. Use Wait mode instead of Backup mode. 46.1.2.2 ADC: Trigger Launches only One Conversion A start command initiates a conversion sequence of one channel but not all activated channels as expected. Problem Fix/Workaround Send as many start commands as the number of activated channels, or use free run mode. 46.1.2.3 ADC12B: Saturation When the ADC12B works in saturation (measurements below 0V or above AD12BVREF) the results may be erratic, the value deviation can be around 30 LSB to the expected data. Problem Fix/Workaround None. 46.1.2.4 ADC: Wrong First Conversions The first conversions done by the ADC may be erroneous if the maximum gain (x4 in single ended or x2 in differential mode) is not used. The issue appears after the power-up or if a conversion has not occured for 1 minute. Problem Fix/Workaround Three workarounds are possible: 1. Perform 16 dummy conversions on one channel (whatever conditions used in term of setup of gain, single/differential, offset, and channel selected). The next conversions will be correct for any channels and any settings. Note that these dummy conversions need to be performed if no conversion has occured for 1 minute or for a new chip startup. 2. Perform a dummy conversion on a single ended channel on which an external voltage of ADVREF/2 (±10%) is applied. Use the following conditions for this conversion: gain at 4, offset set at 1. The next conversions will be correct for any channels and any settings. Note that this dummy conversion needs to be performed if no conversion has occured for 1 minute or for a new chip startup. 3. Perform a dummy conversion on a differential channel on which the two inputs are connected together and connected to any voltage (from 0 to ADVREF). Use the following conditions for this conversion: gain at 4, offset set at 1. The next conversions will be correct for any channels and any settings. Note that this dummy conversion needs to be performed if no conversion has occured for 1 minute or for a new chip startup. SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1139 46.1.3 Power Management Controller (PMC) 46.1.3.1 PMC: Main Oscillator Frequency selection if the Main On-chip RC Oscillator is OFF When the 4/8/12 MHz RC Oscillator is off, the frequency selection (MOSCRCF field in CKGR_MOR) can not be changed. The register can be written but the modification to MOSCRCF will not be taken into account. Problem Fix/Workaround Modify MOSCRCF while 4/8/12 MHz RC Oscillator is on (MOSCREN = 1). 1140 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 46.2 SAM3U Errata - Rev. B Parts Revision B parts Chip IDs are as follows: SAM3U1C (Rev B) 0x28090562 SAM3U1E (Rev B) 0x28190562 46.2.1 Flash 46.2.1.1 Flash: Issue Running at Frequency Lower than 5 MHz When the system clock (MCK) is lower than 5 MHz with two Wait States (WS) programmed in the EEFC Flash Mode Register (EEFC_FMR), the Cortex fetches erroneous instructions. Problem Fix/Workaround Do not use two WS when running at a frequency lower than 5 MHz. 46.2.1.2 Flash: Flash Programming When writing data into the Flash memory plane (either through the EEFC, using the IAP function, or FFPI), the data may not be correctly written (i.e., the data written is not the one expected). Problem Fix/Workaround Set the number of Wait States (WS) to 6 (FWS = 6) during the programming. 46.2.1.3 Flash: Fetching Error after Reading the Unique Identifier After reading the Unique Identifier (or using the STUI/SPUI command), the processor may fetch wrong instructions. It depends on the code and on the region of the code. Problem Fix/Workaround In order to avoid this problem, follow the steps below: 1. Set bit 16 of EEFC_FMR to 1 2. Send the Start Read Unique Identifier command (STUI) by writing the EEFC Flash Command Register (EEFC_FCR) with the STUI command. 3. Wait for the FRDY bit to fall 4. Read the Unique ID (and next bits if required) 5. Send the Stop Read Unique Identifier command (SPUI) by writing the EEFC_FCR with the SPUI command. 6. Wait for the FRDY bit to rise 7. Clear bit 16 of EEFC_FMR Note: During the sequence, the software cannot run out of Flash (so needs to run out of SRAM). SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1141 46.2.2 12-bit Analog-to-Digital Converter (ADC12B) 46.2.2.1 ADC12B: Current Consumption in Backup Mode on VDDANA In Backup mode, the current consumption on VDDANA is around 1.0 mA instead of 0.1 µA Problem Fix/Workaround Four workarounds are possible: 1. Do not supply VDDANA and VDDIO in Backup mode using an external switch managed by SHDN pin. 2. Do not supply VDDANA in Backup mode using an external switch managed by the SHDN and set all PIOs with ADC inputs (PA22, PA30, PB3–PB8, PC15–PC18, PC28–C21) at low level (either externally or by software). 3. Do not supply VDDANA in Backup mode using an external switch managed by any PIO and set all PIOs with ADC inputs (PA22, PA30, PB3–PB8, PC15–PC18, PC28–C21) at low level (either externally or by software). Since the PIO state is preserved when in backup mode, any free PIO line can be used to switch off the external switch by driving the PIO line at low level (PIO is input, pull-up enabled after backup reset). 4. Use Wait mode instead of Backup mode. 46.2.2.2 ADC: Trigger Launches only One Conversion A start command initiates a conversion sequence of one channel but not all activated channels as expected. Problem Fix/Workaround Send as many start commands as the number of activated channels, or use free run mode. 46.2.2.3 ADC: Wrong First Conversions The first conversions done by the ADC may be erroneous if the maximum gain (x4 in single ended or x2 in differential mode) is not used. The issue appears after the power-up or if a conversion has not occured for 1 minute. Problem Fix/Workaround Three workarounds are possible: 1. Perform 16 dummy conversions on one channel (whatever conditions used in term of setup of gain, single/differential, offset, and channel selected). The next conversions will be correct for any channels and any settings. Note that these dummy conversions need to be performed if no conversion has occured for 1 minute or for a new chip startup. 2. Perform a dummy conversion on a single ended channel on which an external voltage of ADVREF/2 (±10%) is applied. Use the following conditions for this conversion: gain at 4, offset set at 1. The next conversions will be correct for any channels and any settings. Note that this dummy conversion needs to be performed if no conversion has occured for 1 minute or for a new chip startup. 3. Perform a dummy conversion on a differential channel on which the two inputs are connected together and connected to any voltage (from 0 to ADVREF). Use the following conditions for this conversion: gain at 4, offset set at 1. The next conversions will be correct for any channels and any settings. Note that this dummy conversion needs to be performed if no conversion has occured for 1 minute or for a new chip startup. 46.2.3 Power Management Controller (PMC) 46.2.3.1 PMC: Main Oscillator Frequency selection if the Main On-chip RC Oscillator is OFF When the 4/8/12 MHz RC Oscillator is off, the frequency selection (MOSCRCF field in CKGR_MOR) can not be changed. The register can be written but the modification to MOSCRCF will not be taken into account. Problem Fix/Workaround Modify MOSCRCF while 4/8/12 MHz RC Oscillator is on (MOSCREN = 1). 1142 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 47. Revision History In the tables that follow, the most recent version of the document appears first. Table 47-1. Doc. Date SAM3U Datasheet Rev. 6430G Revision History Changes Reformatted document General editorial changes throughout “Description” on page 1: - in first paragraph, replaced “an RTC” with “a low-power RTC” - added paragraph relating to low-power modes - added paragraph relating to Real-time Event Management Section 1. ”Features” Updated description of “Low Power Modes” Table 1-1, “Configuration Summary”: reorganized contents; added SPI feature; provided details specific to 12-bit and 10-bit ADCs Section 2. ”Block Diagram” Figure 2-1 ”144-pin SAM3U4/2/1E Block Diagram”: corrected “VDDUTMII” to “VDDUTMI”; deleted TC1 and TC2 to reflect single 3-channel timer counter block TC0 Figure 2-2 ”100-pin SAM3U4/2/1C Block Diagram”: corrected “VDDUTMII” to “VDDUTMI”; deleted TC1 and TC2 to reflect single 3-channel timer counter block TC0 Table 3-1, “Signal Description List”: corrected two instances of “VDDUTMII” to “VDDUTMI” Section 3. ”Signal Description” Section 3.1 ”Design Considerations”: updated to provide title and number of referenced application note Updated Section 4. ”Package and Pinout” 31-Mar-15 Section 5. ”Power Considerations” Added Section 5.2 ”Power-up Considerations” Section 5.4 ”Typical Powering Schematics”: in first sentence and in Figure 5-2 ”Single Supply”, corrected supply voltage range “1.8V-3.6V” to “1.62–3.6 V” Table 5-1, “Low Power Mode Configuration Summary”: replaced “BOD alarm” with “SM alarm” in potential wake-up sources for Backup mode Updated Section 5.7 ”Wake-up Sources” Updated Section 5.8 ”Fast Startup” Section 6. ”Input/Output Lines” Section 6.7 ”ERASE Pin”: in first paragraph, added details relative to reprogamming Flash content Section 7. ”Architecture” (changed title—was previously “Processor and Architecture”) Removed section 7.1 “ARM Cortex-M3 Processor” Removed section 7.8 “Debug and Test Features” Section 8. ”Memories” Inserted Section 8.1 ”Memory Mapping” (was previously section 8. “Product Mapping”) Updated Section 8.2.1 ”Internal SRAM”, Section 8.2.3.4 ”Lock Regions”, and Section 8.2.3.10 ”GPNVM Bits” Section 8.2.4 ”Boot Strategies”: deleted sentence “The GPNVM bit can be cleared or set respectively through the commands “Clear General-purpose NVM Bit” and “Set General-purpose NVM Bit” of the EEFC User Interface” (this information is already provided in Section 8.2.3.10 ”GPNVM Bits”) Added Section 9. ”Real-time Event Management” SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1143 Table 47-1. Doc. Date SAM3U Datasheet Rev. 6430G Revision History (Continued) Changes Revised Section 10. ”System Controller” Section 11. ”Peripherals” Table 11-2, “Multiplexing on PIO Controller A (PIOA)”: added two footnotes on selecting extra functions Table 11-3, “Multiplexing on PIO Controller B (PIOB)”: added three footnotes on selecting extra functions Table 11-4, “Multiplexing on PIO Controller C (PIOC)”: replaced footnotes with two footnotes on selecting extra functions Removed section 12. Embedded Peripherals Overview Section 13. ”Debug and Test Features” Added Section 13.2 ”Embedded Characteristics” Section 13.5.7 ”IEEE 1149.1 JTAG Boundary Scan”: in second paragraph, changed “enabled when FWUP, NRSTB and JTAGSEL are high” to “enabled when FWUP, NRST, NRSTB and JTAGSEL are high” Section 13.5.2 ”Debug Architecture”: in first sentence, corrected “embeds four functional units” to “embeds five functional units” Section 19. ”General Purpose Backup Registers (GPBR)” Updated to correct number of registers from 4 to 8 Section 22. ”SAM3U4/2/1 Boot Program” Updated Section 22.4.3 ”USB Device Port” Section 22.4.4 ”In Application Programming (IAP) Feature”: replaced two instances of “MC_FSR register” with “EEFC_FSR” Section 25. ”Peripheral DMA Controller (PDC)” Deleted sentence “This document describes the AHB Peripheral DMA Controller (AHB PDC) version 1.0.0.” 31-Mar-15 Section 27. ”Power Management Controller (PMC)” Section 27.14.15 ”PMC Status Register”: in FOS bit description, corrected second value to ‘1’ (was ‘0’) Updated Section 27.13 ”Register Write Protection” Section 27.14.10 ”PMC Clock Generator PLLA Register”: updated DIVA field description Updated Section 27.14.20 ”PMC Write Protection Mode Register” Updated Section 27.14.21 ”PMC Write Protection Status Register” Section 35. ”Timer Counter (TC)” Replaced instances of “Master clock” or “MCK” with “peripheral clock” throughout Replaced instances of ‘quadrature decoder logic’ with ‘quadrature decoder’ or ‘QDEC’ throughout Section 35.1 ”Description”: replaced “driven by TIOA0, TIOB0 and TIOA1 inputs” with “driven by TIOA0, TIOB0 and TIOB1 inputs” Section 35.2 ”Embedded Characteristics”: changed “Two multi-purpose input/output signals” to “Two multi-purpose input/output signals acting as trigger event”; deleted last bullet “Two global registers that act on all TC channels” Moved Table 35-1, “Timer Counter Clock Assignment” from Section 35.1 ”Description” to Section 35.3 ”Block Diagram” and updated table footnote Section 35.5.2 ”Power Management”: specified “clock of each channel” at end of paragraph Section 35.5.3 ”Interrupt Sources”: changed title (was “Interrupt”); specified “an interrupt line per channel” in first sentence Added Table 35-5, “Peripheral IDs” Updated Section 35.6.2 ”16-bit Counter” Section 35.6.3 ”Clock Selection”: updated names of internal clock signals Section 35.6.11.1 ”WAVSEL = 00”: replaced “0xFFFF” with “216-1” in first paragraph 1144 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 47-1. Doc. Date SAM3U Datasheet Rev. 6430G Revision History (Continued) Changes Section 35. ”Timer Counter (TC)” (cont’d) In Figure 35-9 ”WAVSEL = 10 without Trigger” and Figure 35-10 ”WAVSEL = 10 with Trigger”, replaced “0xFFFF” with “2n-1” (with “n” representing counter size) Section 35.6.11.3 ”WAVSEL = 01”: replaced “0xFFFF” with “216--1” in first paragraph In Figure 35-13 ”WAVSEL = 11 without Trigger” and Figure 35-14 ”WAVSEL = 11 with Trigger”, replaced “0xFFFF” with “2n-1” (with “n” representing counter size) Section 35.6.14.1 ”Description”: in first paragraph, changed TIOA1 into TIOB1 and corrected link to Figure 35-15 Section 35.6.14.2 ”Input Pre-processing”: deleted sentence “Filters can be disabled using the FILTER bit in the TC_BMR” Figure 35-16 ”Input Stage”: replaced “FILTER” with “MAXFILTER > 0” Section 35.6.14.3 ”Direction Status and Change Detection”: rewrote sixth paragraph for clarity Section 35.6.14.4 ”Position and Rotation Measurement”: rewrote first paragraph for clarity and changed TIOA1 into TIOB1; at end of second paragraph, defined External Trigger Edge and External Trigger configuration in TC_CMR Section 35.6.14.5 ”Speed Measurement”: in fifth paragraph, replaced “EDGTRG can be set to 0x01” with “ETRGEDG must be set to 0x01”; in seventh paragraph, replaced sentence “The speed can be read on TC_RA0 register in TC_CMR0” with “The speed can be read on field RA in register TC_RA0” Table 35-6, “Register Mapping”: defined offset range 0xE8–0xFC as reserved Section 35.7.2 ”TC Channel Mode Register: Capture Mode”: in ‘Name’ line, replaced “(WAVE = 0)” with “(CAPTURE_MODE)”; updated TCCLKS field values 0–4 Section 35.7.3 ”TC Channel Mode Register: Waveform Mode”: in ‘Name’ line, replaced “(WAVE = 1)” with “(WAVEFORM_MODE)”; updated TCCLKS field values 0–4; added note to ENETRG bit description description Section 35.7.4 ”TC Counter Value Register”: in CV field description, added notation “IMPORTANT: For 16-bit channels, CV field size is limited to register bits 15:0” 31-Mar-15 Section 35.7.5 ”TC Register A”: in RA field description, added notation “IMPORTANT: For 16-bit channels, RA field size is limited to register bits 15:0” Section 35.7.6 ”TC Register B”: in RB field description, added notation “IMPORTANT: For 16-bit channels, RB field size is limited to register bits 15:0” Section 35.7.7 ”TC Register C”: in RC field description, added notation “IMPORTANT: For 16-bit channels, RC field size is limited to register bits 15:0” Section 35.7.8 ”TC Status Register”: updated bit descriptions Section 35.7.13 ”TC Block Mode Register”: - removed FILTER bit (register bit 19 now reserved) - corrected TC2XC2S field configuration values: value 2 is TIOA0 (was TIOA1); value 3 is TIOA1 (was TIOA2) Section 42. ”Electrical Characteristics” Updated and harmonized parameter symbols throughout Table 42-2, “DC Characteristics”: corrected VDDUTMII to VDDUTMI; updated values for parameter “On-die Series Termination Resistor”; removed parameter “Input Capacitance” Table 42-4, “Core Power Supply Brownout Detector Characteristics”: added parameter “Reset Period” Table 42-6, “Backup Power Supply Zero-Power-on Reset Characteristics”: renamed parameter “Reset Time-out Period” to “Reset Period” Table 42-17, “4/8/12 MHz RC Oscillators Characteristics”: removed parameter “Frequency Temperature Dependency” Table 42-18, “32.768 kHz Crystal Oscillator Characteristics”: updated conditions for parameters “Startup Time” and “Current Consumption”; added parameter “Allowed Crystal Capacitance Load” Figure 42-10 ”32.768 kHz Crystal Oscillator Schematic”: added “Ccrystal” label Table 42-20, “XIN32 Clock Electrical Characteristics (In Bypass Mode)”: in footnote, corrected “32768 kHz” to “32.768 kHz” SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1145 Table 47-1. Doc. Date SAM3U Datasheet Rev. 6430G Revision History (Continued) Changes Section 42. ”Electrical Characteristics” (cont’d) Updated Figure 42-11 ”XIN32 Clock Timing” Table 42-21, “3 to 20 MHz Crystal Oscillator Characteristics”: updated values for parameter “External capacitor on XIN and XOUT”; added parameter “Allowed Crystal Capacitance Load”; deleted all footnotes Updated Figure 42-13 ”XIN Clock Timing” Updated Section 42.4.9 ”Crystal Oscillators Design Consideration Information” Table 42-25, “PLLA Characteristics”: updated min/max values for parameters “Input Frequency” and “Output Frequency” Table 42-25, “PLLA Characteristics”: added max value for Current Consumption (Standby mode) Table 42-28, “Static Power Consumption”: corrected VDDUTMII to VDDUTMI Table 42-29, “Dynamic Power Consumption”: corrected VDDUTMII to VDDUTMI Deleted section 43.6.5 “USB High Speed Design Guidelines” Table 42-30, “Analog Power Supply Characteristics”: changed VDDIN to VDDANA Table 42-32, “External Voltage Reference Input”: changed VDDIN to VDDANA Updated Section 42.7.1 ”Static Performance Characteristics” Table 42-33, “INL, DNL, 12-bit mode, VDDANA Supply Voltage Conditions”: changed VDDIN to VDDANA Table 42-34, “Gain Error, Offset Error, 12-bit Mode, VDDANA Supply Voltage Conditions(1)”: changed VDDIN to VDDANA Inserted heading Section 42.7.2 ”Dynamic Performance Characteristics” and updated content Replaced section “Track and Hold Time versus Source Output Impedance” with Section 42.7.2.1 ”Sample and Hold Time versus Source Output Impedance” Table 42-39, “Analog Inputs”: in footnote, changed VDDIN to VDDANA 31-Mar-15 Restored Section 42.8 ”10-bit Successive Approximation Register (SAR) ADC Characteristics” (content was inadvertently removed in version 6430F of this datasheet) Section 42.9.3.1 ”Maximum SPI Frequency”: updated content under ”Master Write Mode” and ”Master Read Mode” Table 42-49, “SSC Timings”: updated parameters SSC4 and SSC7; deleted footnote “Timings SSC4 and SSC7 depend on...” Section 42.9 ”AC Characteristics”: removed Figure 43-27. “USART SPI Master Mode”, Figure 43-28. “USART SPI Slave mode (Mode 1 or 2)”, Figure 43-29. “USART SPI Slave mode (Mode 0 or 3)”, and Table 43-49. “USART SPI Timings” Table 42-54, “Two-wire Serial Bus Requirements”: in bottom row, replaced duplicated parameter “Hold Time (repeated) START Condition” with new parameter “Bus free time between a STOP and START condition” Section 42.9.8 ”Embedded Flash Characteristics”: in first paragraph, corrected “field FWS of the MC_FMR register” to “field FWS of the EEFC_FMR”; updated text and replaced two wait state tables with single Table 42-55, “Embedded Flash Wait State - VDDCORE 1.62V/1.80V” Section 43. ”Mechanical Characteristics” Figure 43-1 ”100-lead LQFP Package Drawing”: added notes 1 and 2 Section 43.2 ”100-ball TFBGA Package”: at end of section, added sentence “This package respects the recommendations of the NEMI User Group.” Figure 43-2 ”100-ball TFBGA Package Drawing”: corrected ‘A’ maximum dimension in inches from 0.0575 to 0.0433 Updated Table 43-4, “100-ball TFBGA Soldering Information (Substrate Level)” Updated Table 43-5, “100-ball TFBGA Device Maximum Weight” Updated Table 43-7, “100-ball TFBGA Package Reference” Section 43.3 ”144-lead LQFP Package”: at end of section, added sentence “This package respects the recommendations of the NEMI User Group.” Updated Table 43-8, “144-lead LQFP Device Maximum Weight” 1146 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 Table 47-1. Doc. Date SAM3U Datasheet Rev. 6430G Revision History (Continued) Changes Inserted Section 44. ”Marking” (was previously in Section 46. ”SAM3U Series Errata”) Section 45. ”Ordering Information” Table 45-1, “SAM3U Ordering Information”: removed “Package Type” column (this information is provided on the Atmel website) Section 46. ”SAM3U Series Errata” 31-Mar-15 Deleted sentence referencing application note “Errata on SAM3U Engineering Sample Devices” Section 46.1.1.1 ”Flash: Issue Running at Frequency Lower than 5 MHz”: changed lower frequency limit from 2.5 MHz to 5 MHz Section 46.2.1.1 ”Flash: Issue Running at Frequency Lower than 5 MHz”: changed lower frequency limit from 2.5 MHz to 5 MHz Section 46.1.2.3 ”ADC12B: Saturation”: corrected instance of “ADREF” to “AD12BVREF” Doc. Rev. 6430F Change Request Ref.(1) Comments PMC: Section 27.9 ”Fast Startup”, SUPC_FSMR --> PMC_FSMR and SUPC_FSPR --> PMC_FSPR 8010 Section 27.3 ”Master Clock Controller”, removed bogus sentence about Master Clock divider functionality rfo Section 27.1 ”Description”, changed sentence “Processor Clock (HCLK), must be switched off...” 8217 Memories: Section 8.2.3.1 ”Flash Overview”, Flash size should be 64KBytes instead of 256KBytes 8029 Electrical Characteristics: Section 43.7, 43.7.1 Gain and Offset Calibration removed 8031 Section 42.4 ”Crystal Oscillators Characteristics”: 8174 Table 42-16, “32 kHz RC Oscillator Characteristics”, changed parameter ‘Frequency Temperature Dependency’ Table 42-4, “Core Power Supply Brownout Detector Characteristics”, changed MAX value of VTH+ Section 42.9.8 ”Embedded Flash Characteristics”, added note regarding erasing Flash contents 8223 Errata: Section 46.2 ”SAM3U Errata - Rev. B Parts”, added errata section for rev. B 8131 Section 46.1 ”SAM3U Errata - Rev. A Parts”: Section 46.1.2.2 ”ADC: Trigger Launches only One Conversion”, added errata rfo Section 46.2 ”SAM3U Errata - Rev. B Parts”: Section 46.2.2.2 ”ADC: Trigger Launches only One Conversion”, added errata rfo Section 46.1 ”SAM3U Errata - Rev. A Parts”: Section 46.1.2.4 ”ADC: Wrong First Conversions”, added errata 8164 Section 46.2 ”SAM3U Errata - Rev. B Parts”: Section 46.2.2.3 ”ADC: Wrong First Conversions”, added errata Overview & Mechanical Characteristics: Replaced all occurrences of '100-ball LFBGA' into '100-ball TFBGA' 8044 Ordering Information: Table 45-1, “SAM3U Ordering Information”, updated with MRL B devices 8130 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1147 Doc. Rev. 6430F Comments (Continued) Change Request Ref.(1) SPI: Section 32.8.11 ”SPI Write Protection Status Register”, description of register simplified 8136 Section 32.8.10 ”SPI Write Protection Mode Register”, removed ‘SPI’ from register description names rfo Section 32. ”Serial Peripheral Interface (SPI) Programmer Datasheet”, SPI version updated to version ‘R’ rfo TC: Section 34.1 ”Description”: Table 34-1, “Timer Counter Clock Assignment”, footnote for table updated Doc. Rev. 6430E Comments 8159 Change Request Ref.(1) Overview: Comment in front of rows PA24 and PA25 removed, and put as a footnote(4) for TWD1 and TWCK1. Table 11-2, “Multiplexing on PIO Controller A (PIOA)”, “Peripheral B” column, PA2 and PA17 texts exchanged. 7724 Figure ”The fast restart circuitry (shown in Figure 27-3 “Fast Startup Circuitry” on page 454) is fully asynchronous and provides a fast startup signal to the Power Management Controller. As soon as the fast startup signal is asserted, the PMC automatically restarts the embedded 4/8/12 MHz fast RC oscillator, switches the master clock on this 4 MHz clock by default and reenables the processor clock.”, ‘Falling/Rising Edge Detector’ changed to ‘High/Low Level Detector’ in 3 blocks. 7954 7922 rfo Wait mode consumption updated in Table 5-1, “Low Power Mode Configuration Summary” Clock Generator: Last sentence removed from Section 26.5.1 ”Divider and Phase Lock Loop Programming”, as PLLADIV2 does 7751 not exist. 7908 Third bullet edited in Section 26.1 ”Description”. Electrical Characteristics: 3 values updated in Table 42-12, “Typical Current Consumption in Wait Mode”. rfo Section 43.7.1 ”Sample and Hold Time versus Source Output Impedance” created. SUPC: Section 19.3.2 ”Slow Clock Generator”, variable VDD_SUPPLY_MONITOR changed to VDD_Backup, in order 7743 to get VDDBU instead of VDDUTMI. PMC: Section 27.8 ”Programmable Clock Output Controller”, UPLLCK --> UPLLCK/2. 7898 Figure 27-1, “General Clock Block Diagram” edited (UPLLCK --> UPLLCK/2, and UPLLDIV /1/2 --> Divider /2) 7912 USART: Section 35. ”Universal Synchronous Asynchronous Receiver Transmitter (USART)”, PDC condition shown instead of DMA. 7804 Errata: Section 46.1.1.4 ”Flash: Fetching Error after Reading the Unique Identifier” added. 1148 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 7978 Doc. Rev. 6430D Change Request Ref.(1) Comments Overview: Section 5.6.2 ”Wait Mode”, sentence starting with ‘By configuring...’ --> ‘This is done by configuring...’ 7492 Section 11. ”Peripherals”, (Rev A) was removed from Table 10-1. 7642 TWD1 and TWCK1 removed from Figure 2-2, “100-pin SAM3U4/2/1C Block Diagram”. 7624 Table 3-1, “Signal Description List”, Note (4) added to TDO Output. 7635 A typo fixed in Section 8.2.1 ”Internal SRAM”: 4224 Kbytes --> 4224 bytes. 7305 Debug and Test Features: Table 13-1, “Debug and Test Signal List”, Note (1) added to TDO Output. 7635 Section 13.5.8 ”ID Code Register”, Chip ID and JTAG ID Code edited. 7543 Section 13.5.7 ”IEEE 1149.1 JTAG Boundary Scan”, second paragraph updated. 7485 Chip ID: CHIPID_CIDR column in Table 29-1, “ATSAM3U Chip IDs Register” updated as in Table 9-1 7642 Clock Generator: Section 26.6 ”UTMI Phase Lock Loop Programming”, first sentence edited, together with Table 26-5, “UTMI PLL Block Diagram”. 7484 PMC: Section 27.9 ”Fast Startup”, a sentence starting with ‘Important’ added as a second paragraph. In the first paragraph, ‘LPM bit is at 0’ replaced by ‘LPM bit is at 1’. 7539 Section 27.14.15 ”PMC Status Register”, MOSCSELS bit descriptions reversed. 7389 Electrical Characteristics: In Table 42-18, “32.768 kHz Crystal Oscillator Characteristics”, CLEXT Maximum value is 22 instead of 20. 7589 Section 42.9.7 ”Two-wire Serial Interface Characteristics” updated: UART --> USART, SPCK --> SCK, Figures and titles updated. 7320 Errata: Section 46.1.2.1 ”ADC12B: Current Consumption in Backup Mode on VDDANA” edited. 7420 Section 46.1.1.3 ”Flash: Flash Programming” added. 7205 Backpage: A typo fixed: ‘tehincal’ --> ‘technical’ 7536 SAM3U Series [DATASHEET] Atmel-6430G-ATARM-SAM3U-Series-Datasheet_31-Mar-15 1149 Doc. Rev. 6430C Comments Change Request Ref.(1) Overview: Section 2. ”SAM3U Block Diagram”, changed orientation of block diagrams. rfo Section 5. ”Power Considerations”, fixed grammar in Voltage ranges. Section 3. ”Signal Description”, USART signal DCD0 is an Input 6681 Figure 5-1, “Single Supply”, Main supply range is 1.8V-3.6V. 6698 Figure 5-1, Figure 5-2, Figure 5-3, updated “Note” below figures, “With Main Supply