LU MI NA RY M I C R O C ON F I D E N T I A L - A D VA N C E P R OD U C T I N F ORMATI ON LM3S8938 Microcontroller D ATA SH E E T D S -LM3 S 8 938 - 0 1 Copyr i ght © 2007 Lum i nar y M i c ro, Inc. Legal Disclaimers and Trademark Information INFORMATION IN THIS DOCUMENT IS PROVIDED IN CONNECTION WITH LUMINARY MICRO PRODUCTS. NO LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. EXCEPT AS PROVIDED IN LUMINARY MICRO'S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, LUMINARY MICRO ASSUMES NO LIABILITY WHATSOEVER, AND LUMINARY MICRO DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY, RELATING TO SALE AND/OR USE OF LUMINARY MICRO'S PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. LUMINARY MICRO'S PRODUCTS ARE NOT INTENDED FOR USE IN MEDICAL, LIFE SAVING, OR LIFE-SUSTAINING APPLICATIONS. Luminary Micro may make changes to specifications and product descriptions at any time, without notice. Contact your local Luminary Micro sales office or your distributor to obtain the latest specifications before placing your product order. Designers must not rely on the absence or characteristics of any features or instructions marked "reserved" or "undefined." Luminary Micro reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them. Copyright © 2007 Luminary Micro, Inc. All rights reserved. Stellaris is a registered trademark and Luminary Micro and the Luminary Micro logo are trademarks of Luminary Micro, Inc. or its subsidiaries in the United States and other countries. ARM and Thumb are registered trademarks and Cortex is a trademark of ARM Limited. Other names and brands may be claimed as the property of others. Luminary Micro, Inc. 108 Wild Basin, Suite 350 Austin, TX 78746 Main: +1-512-279-8800 Fax: +1-512-279-8879 http://www.luminarymicro.com 2 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Table of Contents About This Document .................................................................................................................... 20 Audience .............................................................................................................................................. About This Manual ................................................................................................................................ Related Documents ............................................................................................................................... Documentation Conventions .................................................................................................................. 20 20 20 20 1 Overview ............................................................................................................................. 22 1.1 1.2 1.3 1.4 1.4.1 1.4.2 1.4.3 1.4.4 1.4.5 1.4.6 1.4.7 Product Features ...................................................................................................................... Target Applications .................................................................................................................... High-Level Block Diagram ......................................................................................................... Functional Overview .................................................................................................................. ARM Cortex™-M3 ..................................................................................................................... Motor Control Peripherals .......................................................................................................... Serial Communications Peripherals ............................................................................................ System Peripherals ................................................................................................................... Memory Peripherals .................................................................................................................. Additional Features ................................................................................................................... Hardware Details ...................................................................................................................... 2 Cortex-M3 Core .................................................................................................................. 35 2.1 2.2 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 Block Diagram .......................................................................................................................... Functional Description ............................................................................................................... Serial Wire and JTAG Debug ..................................................................................................... Embedded Trace Macrocell (ETM) ............................................................................................. Trace Port Interface Unit (TPIU) ................................................................................................. ROM Table ............................................................................................................................... Memory Protection Unit (MPU) ................................................................................................... Nested Vectored Interrupt Controller (NVIC) ................................................................................ 3 Memory Map ....................................................................................................................... 41 4 Interrupts ............................................................................................................................ 43 5 JTAG .................................................................................................................................... 46 5.1 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.3 5.4 5.4.1 5.4.2 Block Diagram .......................................................................................................................... Functional Description ............................................................................................................... JTAG Interface Pins .................................................................................................................. JTAG TAP Controller ................................................................................................................. Shift Registers .......................................................................................................................... Operational Considerations ........................................................................................................ Initialization and Configuration ................................................................................................... Register Descriptions ................................................................................................................ Instruction Register (IR) ............................................................................................................. Data Registers .......................................................................................................................... 6 System Control ................................................................................................................... 57 6.1 6.1.1 6.1.2 6.1.3 Functional Description ............................................................................................................... Device Identification .................................................................................................................. Reset Control ............................................................................................................................ Power Control ........................................................................................................................... June 14, 2007 22 27 27 28 29 29 30 31 32 33 33 36 36 36 37 37 37 37 37 47 47 48 49 50 50 53 53 53 55 57 57 57 60 3 Luminary Micro Confidential-Advance Product Information Table of Contents 6.1.4 6.1.5 6.2 6.3 6.4 Clock Control ............................................................................................................................ System Control ......................................................................................................................... Initialization and Configuration ................................................................................................... Register Map ............................................................................................................................ Register Descriptions ................................................................................................................ 7 Hibernation Module .......................................................................................................... 113 7.1 7.2 7.2.1 7.2.2 7.2.3 7.2.4 7.2.5 7.2.6 7.2.7 7.3 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 7.4 7.5 Block Diagram ........................................................................................................................ Functional Description ............................................................................................................. Register Access Timing ........................................................................................................... Clock Source .......................................................................................................................... Battery Management ............................................................................................................... Real-Time Clock ...................................................................................................................... Non-Volatile Memory ............................................................................................................... Power Control ......................................................................................................................... Interrupts and Status ............................................................................................................... Initialization and Configuration ................................................................................................. Initialization ............................................................................................................................. RTC Match Functionality (No Hibernation) ................................................................................ RTC Match/Wake-Up from Hibernation ..................................................................................... External Wake-Up from Hibernation .......................................................................................... RTC/External Wake-Up from Hibernation .................................................................................. Register Map .......................................................................................................................... Register Descriptions .............................................................................................................. 8 Internal Memory ............................................................................................................... 131 8.1 8.2 8.2.1 8.2.2 8.3 8.3.1 8.3.2 8.4 8.5 8.6 Block Diagram ........................................................................................................................ 131 Functional Description ............................................................................................................. 131 SRAM Memory ........................................................................................................................ 131 Flash Memory ......................................................................................................................... 132 Flash Memory Initialization and Configuration ........................................................................... 133 Flash Programming ................................................................................................................. 133 Nonvolatile Register Programming ........................................................................................... 134 Register Map .......................................................................................................................... 134 Flash Control Offset ................................................................................................................. 135 System Control Offset .............................................................................................................. 142 9 GPIO .................................................................................................................................. 155 9.1 9.1.1 9.1.2 9.1.3 9.1.4 9.1.5 9.1.6 9.2 9.3 9.4 Function Description ................................................................................................................ 155 Data Control ........................................................................................................................... 155 Interrupt Control ...................................................................................................................... 156 Mode Control .......................................................................................................................... 157 Commit Control ....................................................................................................................... 157 Pad Control ............................................................................................................................. 157 Identification ........................................................................................................................... 158 Initialization and Configuration ................................................................................................. 158 Register Map .......................................................................................................................... 159 Register Descriptions .............................................................................................................. 161 10 Timers ............................................................................................................................... 196 10.1 Block Diagram ........................................................................................................................ 197 4 60 62 63 63 64 114 114 114 115 115 115 116 116 116 116 117 117 117 117 118 118 118 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 10.2 10.2.1 10.2.2 10.2.3 10.3 10.3.1 10.3.2 10.3.3 10.3.4 10.3.5 10.3.6 10.4 10.5 Functional Description ............................................................................................................. GPTM Reset Conditions .......................................................................................................... 32-Bit Timer Operating Modes .................................................................................................. 16-Bit Timer Operating Modes .................................................................................................. Initialization and Configuration ................................................................................................. 32-Bit One-Shot/Periodic Timer Mode ....................................................................................... 32-Bit Real-Time Clock (RTC) Mode ......................................................................................... 16-Bit One-Shot/Periodic Timer Mode ....................................................................................... 16-Bit Input Edge Count Mode ................................................................................................. 16-Bit Input Edge Timing Mode ................................................................................................ 16-Bit PWM Mode ................................................................................................................... Register Map .......................................................................................................................... Register Descriptions .............................................................................................................. 11 Watchdog Timer ............................................................................................................... 229 11.1 11.2 11.3 11.4 11.5 Block Diagram ........................................................................................................................ Functional Description ............................................................................................................. Initialization and Configuration ................................................................................................. Register Map .......................................................................................................................... Register Descriptions .............................................................................................................. 12 ADC ................................................................................................................................... 252 12.1 12.2 12.2.1 12.2.2 12.2.3 12.2.4 12.2.5 12.2.6 12.3 12.3.1 12.3.2 12.4 12.5 Block Diagram ........................................................................................................................ 253 Functional Description ............................................................................................................. 253 Sample Sequencers ................................................................................................................ 253 Module Control ........................................................................................................................ 254 Hardware Sample Averaging Circuit ......................................................................................... 255 Analog-to-Digital Converter ...................................................................................................... 255 Test Modes ............................................................................................................................. 255 Internal Temperature Sensor .................................................................................................... 255 Initialization and Configuration ................................................................................................. 256 Module Initialization ................................................................................................................. 256 Sample Sequencer Configuration ............................................................................................. 256 Register Map .......................................................................................................................... 257 Register Descriptions .............................................................................................................. 258 13 UART ................................................................................................................................. 285 13.1 13.2 13.2.1 13.2.2 13.2.3 13.2.4 13.2.5 13.2.6 13.2.7 13.2.8 13.3 13.4 13.5 Block Diagram ........................................................................................................................ Functional Description ............................................................................................................. Transmit/Receive Logic ........................................................................................................... Baud-Rate Generation ............................................................................................................. Data Transmission .................................................................................................................. Serial IR (SIR) ......................................................................................................................... FIFO Operation ....................................................................................................................... Interrupts ................................................................................................................................ Loopback Operation ................................................................................................................ IrDA SIR block ........................................................................................................................ Initialization and Configuration ................................................................................................. Register Map .......................................................................................................................... Register Descriptions .............................................................................................................. June 14, 2007 197 197 197 199 203 203 204 204 205 205 206 206 207 229 229 230 230 231 286 286 286 287 288 288 289 289 290 290 290 291 292 5 Luminary Micro Confidential-Advance Product Information Table of Contents 14 SSI ..................................................................................................................................... 325 14.1 14.2 14.2.1 14.2.2 14.2.3 14.2.4 14.3 14.4 14.5 Block Diagram ........................................................................................................................ Functional Description ............................................................................................................. Bit Rate Generation ................................................................................................................. FIFO Operation ....................................................................................................................... Interrupts ................................................................................................................................ Frame Formats ....................................................................................................................... Initialization and Configuration ................................................................................................. Register Map .......................................................................................................................... Register Descriptions .............................................................................................................. 15 Inter-Integrated Circuit (I C) Interface ............................................................................ 359 15.1 15.2 15.2.1 15.2.2 15.2.3 15.2.4 15.2.5 15.3 15.4 15.5 15.6 Block Diagram ........................................................................................................................ Functional Description ............................................................................................................. 2 I C Bus Functional Overview .................................................................................................... Available Speed Modes ........................................................................................................... Interrupts ................................................................................................................................ Loopback Operation ................................................................................................................ Command Sequence Flow Charts ............................................................................................ Initialization and Configuration ................................................................................................. 2 I C Register Map ..................................................................................................................... 2 I C Master .............................................................................................................................. 2 I C Slave ................................................................................................................................ 16 CAN ................................................................................................................................... 394 325 326 326 326 326 327 334 335 336 2 16.1 Controller Area Network Overview ............................................................................................ 16.2 Controller Area Network Features ............................................................................................ 16.3 Controller Area Network Block Diagram .................................................................................... 16.4 Controller Area Network Functional Description ......................................................................... 16.4.1 Initialization ............................................................................................................................. 16.4.2 Operation ............................................................................................................................... 16.4.3 Transmitting Message Objects ................................................................................................. 16.4.4 Configuring a Transmit Message Object .................................................................................... 16.4.5 Updating a Transmit Message Object ....................................................................................... 16.4.6 Accepting Received Message Objects ...................................................................................... 16.4.7 Receiving a Data Frame .......................................................................................................... 16.4.8 Receiving a Remote Frame ...................................................................................................... 16.4.9 Receive/Transmit Priority ......................................................................................................... 16.4.10 Configuring a Receive Message Object .................................................................................... 16.4.11 Handling of Received Message Objects .................................................................................... 16.4.12 Handling of Interrupts .............................................................................................................. 16.4.13 Bit Timing Configuration Error Considerations ........................................................................... 16.4.14 Bit Time and Bit Rate ............................................................................................................... 16.4.15 Calculating the Bit Timing Parameters ...................................................................................... 16.5 Controller Area Network Register Map ...................................................................................... 16.6 Register Descriptions .............................................................................................................. 359 359 360 362 363 363 364 370 371 372 385 394 394 395 396 396 397 397 397 398 398 399 399 399 399 400 400 401 401 403 405 407 17 Ethernet ............................................................................................................................. 438 17.1 17.2 Block Diagram ........................................................................................................................ 439 Functional Description ............................................................................................................. 439 6 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 17.2.1 17.2.2 17.2.3 17.2.4 17.3 17.4 17.5 17.6 Internal MII Operation .............................................................................................................. PHY Configuration/Operation ................................................................................................... MAC Configuration/Operation .................................................................................................. Interrupts ................................................................................................................................ Initialization and Configuration ................................................................................................. Ethernet Register Map ............................................................................................................. Ethernet MAC ......................................................................................................................... MII Management ..................................................................................................................... 439 440 441 443 444 444 446 463 18 Analog Comparators ....................................................................................................... 482 18.1 18.2 18.2.1 18.3 18.4 18.5 Block Diagram ........................................................................................................................ Functional Description ............................................................................................................. Internal Reference Programming .............................................................................................. Initialization and Configuration ................................................................................................. Register Map .......................................................................................................................... Register Descriptions .............................................................................................................. 19 Pin Diagram ...................................................................................................................... 495 20 Signal Tables .................................................................................................................... 496 21 Operating Characteristics ............................................................................................... 510 22 Electrical Characteristics ................................................................................................ 511 483 483 485 486 486 487 22.1 DC Characteristics .................................................................................................................. 511 22.1.1 Maximum Ratings ................................................................................................................... 511 22.1.2 Recommended DC Operating Conditions .................................................................................. 511 22.1.3 On-Chip Low Drop-Out (LDO) Regulator Characteristics ............................................................ 512 22.1.4 Power Specifications ............................................................................................................... 512 22.1.5 Flash Memory Characteristics .................................................................................................. 513 22.2 AC Characteristics ................................................................................................................... 513 22.2.1 Load Conditions ...................................................................................................................... 513 22.2.2 Clocks .................................................................................................................................... 513 22.2.3 Temperature Sensor ................................................................................................................ 514 22.2.4 Analog-to-Digital Converter ...................................................................................................... 514 22.2.5 Analog Comparator ................................................................................................................. 515 2 22.2.6 I C ......................................................................................................................................... 515 22.2.7 Ethernet Controller .................................................................................................................. 516 22.2.8 Hibernation Module ................................................................................................................. 519 22.2.9 Synchronous Serial Interface (SSI) ........................................................................................... 519 22.2.10 JTAG and Boundary Scan ........................................................................................................ 521 22.2.11 General-Purpose I/O ............................................................................................................... 522 22.2.12 Reset ..................................................................................................................................... 523 23 Package Information ........................................................................................................ 525 24 Ordering Information ....................................................................................................... 527 24.1 24.2 24.3 Ordering Information ................................................................................................................ 527 Company Information .............................................................................................................. 527 Support Information ................................................................................................................. 527 A Serial Flash Loader .......................................................................................................... 528 A.1 A.2 Serial Flash Loader ................................................................................................................. 528 Interfaces ............................................................................................................................... 528 June 14, 2007 7 Luminary Micro Confidential-Advance Product Information Table of Contents A.2.1 A.2.2 A.3 A.3.1 A.3.2 A.3.3 A.4 A.4.1 A.4.2 A.4.3 A.4.4 A.4.5 A.4.6 UART ..................................................................................................................................... SSI ......................................................................................................................................... Packet Handling ...................................................................................................................... Packet Format ........................................................................................................................ Sending Packets ..................................................................................................................... Receiving Packets ................................................................................................................... Commands ............................................................................................................................. COMMAND_PING (0X20) ........................................................................................................ COMMAND_GET_STATUS (0x23) ........................................................................................... COMMAND_DOWNLOAD (0x21) ............................................................................................. COMMAND_SEND_DATA (0x24) ............................................................................................. COMMAND_RUN (0x22) ......................................................................................................... COMMAND_RESET (0x25) ..................................................................................................... B Register Quick Reference ............................................................................................... 533 8 528 528 529 529 529 529 530 530 530 530 531 531 531 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller List of Figures Figure 1-1. Figure 2-1. Figure 2-2. Figure 5-1. Figure 5-2. Figure 5-3. Figure 5-4. Figure 5-5. Figure 6-1. Figure 7-1. Figure 8-1. Figure 9-1. Figure 9-2. Figure 10-1. Figure 10-2. Figure 10-3. Figure 10-4. Figure 11-1. Figure 12-1. Figure 12-2. Figure 13-1. Figure 13-2. Figure 13-3. Figure 14-1. Figure 14-2. Figure 14-3. Figure 14-4. Figure 14-5. Figure 14-6. Figure 14-7. Figure 14-8. Figure 14-9. Figure 14-10. Figure 14-11. Figure 14-12. Figure 15-1. Figure 15-2. Figure 15-3. Figure 15-4. Figure 15-5. Figure 15-6. Figure 15-7. Figure 15-8. Figure 15-9. Figure 15-10. Figure 15-11. Stellaris® Fury-class High-Level Block Diagram ................................................................ 28 CPU Block Diagram ......................................................................................................... 36 TPIU Block Diagram ........................................................................................................ 37 JTAG Module Block Diagram ............................................................................................ 47 Test Access Port State Machine ....................................................................................... 50 IDCODE Register Format ................................................................................................. 55 BYPASS Register Format ................................................................................................ 56 Boundary Scan Register Format ....................................................................................... 56 External Circuitry to Extend Reset .................................................................................... 58 Hibernation Module Block Diagram ................................................................................. 114 Flash Block Diagram ...................................................................................................... 131 GPIODATA Write Example ............................................................................................. 156 GPIODATA Read Example ............................................................................................. 156 GPTM Module Block Diagram ........................................................................................ 197 16-Bit Input Edge Count Mode Example .......................................................................... 201 16-Bit Input Edge Time Mode Example ........................................................................... 202 16-Bit PWM Mode Example ............................................................................................ 203 WDT Module Block Diagram .......................................................................................... 229 ADC Module Block Diagram ........................................................................................... 253 Internal Temperature Sensor Characteristic ..................................................................... 256 UART Module Block Diagram ......................................................................................... 286 UART Character Frame ................................................................................................. 287 IrDA Data Modulation ..................................................................................................... 289 SSI Module Block Diagram ............................................................................................. 325 TI Synchronous Serial Frame Format (Single Transfer) .................................................... 328 TI Synchronous Serial Frame Format (Continuous Transfer) ............................................ 328 Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0 ...................................... 329 Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0 .............................. 329 Freescale SPI Frame Format with SPO=0 and SPH=1 ..................................................... 330 Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0 ........................... 331 Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0 .................... 331 Freescale SPI Frame Format with SPO=1 and SPH=1 ..................................................... 332 MICROWIRE Frame Format (Single Frame) .................................................................... 333 MICROWIRE Frame Format (Continuous Transfer) ......................................................... 334 MICROWIRE Frame Format, SSIFss Input Setup and Hold Requirements ........................ 334 2 I C Block Diagram ......................................................................................................... 359 2 I C Bus Configuration .................................................................................................... 360 START and STOP Conditions ......................................................................................... 360 Complete Data Transfer with a 7-Bit Address ................................................................... 361 R/S Bit in First Byte ........................................................................................................ 361 2 Data Validity During Bit Transfer on the I C Bus ............................................................... 361 Master Single SEND ...................................................................................................... 364 Master Single RECEIVE ................................................................................................. 365 Master Burst SEND ....................................................................................................... 366 Master Burst RECEIVE .................................................................................................. 367 Master Burst RECEIVE after Burst SEND ........................................................................ 368 June 14, 2007 9 Luminary Micro Confidential-Advance Product Information Table of Contents Figure 15-12. Figure 15-13. Figure 16-1. Figure 16-2. Figure 17-1. Figure 17-2. Figure 17-3. Figure 18-1. Figure 18-2. Figure 18-3. Figure 19-1. Figure 22-1. Figure 22-2. Figure 22-3. Figure 22-4. Figure 22-5. Figure 22-6. Figure 22-7. Figure 22-8. Figure 22-9. Figure 22-10. Figure 22-11. Figure 22-12. Figure 22-13. Figure 22-14. Figure 22-15. Figure 23-1. Master Burst SEND after Burst RECEIVE ........................................................................ 369 Slave Command Sequence ............................................................................................ 370 CAN Module Block Diagram ........................................................................................... 395 CAN Bit Time ................................................................................................................ 402 Ethernet Controller Block Diagram .................................................................................. 439 Ethernet Controller ......................................................................................................... 439 Ethernet Frame ............................................................................................................. 441 Analog Comparator Module Block Diagram ..................................................................... 483 Structure of Comparator Unit .......................................................................................... 484 Comparator Internal Reference Structure ........................................................................ 485 Pin Connection Diagram ................................................................................................ 495 Load Conditions ............................................................................................................ 513 2 I C Timing ..................................................................................................................... 516 External XTLP Oscillator Characteristics ......................................................................... 518 Hibernation Module Timing ............................................................................................. 519 SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing Measurement .............. 520 SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer ............................. 520 SSI Timing for SPI Frame Format (FRF=00), with SPH=1 ................................................. 521 JTAG Test Clock Input Timing ......................................................................................... 522 JTAG Test Access Port (TAP) Timing .............................................................................. 522 JTAG TRST Timing ........................................................................................................ 522 External Reset Timing (RST) ........................................................................................... 523 Power-On Reset Timing ................................................................................................. 524 Brown-Out Reset Timing ................................................................................................ 524 Software Reset Timing ................................................................................................... 524 Watchdog Reset Timing ................................................................................................. 524 100-Pin LQFP Package .................................................................................................. 525 10 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller List of Tables Table 1. Table 3-1. Table 4-1. Table 4-2. Table 5-1. Table 5-2. Table 6-1. Table 6-2. Table 6-3. Table 7-1. Table 8-1. Table 8-2. Table 8-3. Table 9-1. Table 9-2. Table 9-3. Table 10-1. Table 10-2. Table 11-1. Table 12-1. Table 12-2. Table 13-1. Table 14-1. Table 15-1. Table 15-2. Table 15-3. Table 16-1. Table 16-2. Table 16-3. Table 16-4. Table 17-1. Table 17-2. Table 18-1. Table 18-2. Table 18-3. Table 18-4. Table 18-5. Table 20-1. Table 20-2. Table 20-3. Table 20-4. Table 21-1. Table 21-2. Table 22-1. Table 22-2. Table 22-3. Documentation Conventions ............................................................................................ 20 Memory Map ................................................................................................................... 41 Exception Types .............................................................................................................. 43 Interrupts ........................................................................................................................ 44 JTAG Port Pins Reset State ............................................................................................. 48 JTAG Instruction Register Commands ............................................................................... 53 System Control Register Map ........................................................................................... 63 VADJ to VOUT ................................................................................................................ 68 Default Crystal Field Values and PLL Programming ........................................................... 75 Hibernation Module Register Map ................................................................................... 118 Flash Protection Policy Combinations ............................................................................. 133 Flash Resident Registers ............................................................................................... 134 Internal Memory Register Map ........................................................................................ 134 GPIO Pad Configuration Examples ................................................................................. 158 GPIO Interrupt Configuration Example ............................................................................ 158 GPIO Register Map ....................................................................................................... 160 16-Bit Timer With Prescaler Configurations ..................................................................... 200 Timers Register Map ...................................................................................................... 206 Watchdog Timer Register Map ........................................................................................ 230 Samples and FIFO Depth of Sequencers ........................................................................ 253 ADC Register Map ......................................................................................................... 257 UART Register Map ....................................................................................................... 291 SSI Register Map .......................................................................................................... 335 2 Examples of I C Master Timer Period versus Speed Mode ............................................... 362 2 Inter-Integrated Circuit (I C) Interface Register Map ......................................................... 371 Write Field Decoding for I2CMCS[3:0] Field (Sheet 1 of 3) ................................................ 376 Transmit Message Object Bit Settings ............................................................................. 398 Receive Message Object Bit Settings .............................................................................. 400 CAN Protocol Ranges .................................................................................................... 402 CAN Register Map ......................................................................................................... 405 TX & RX FIFO Organization ........................................................................................... 442 Ethernet Register Map ................................................................................................... 445 Comparator 0 Operating Modes ...................................................................................... 484 Comparator 1 Operating Modes ...................................................................................... 484 Comparator 2 Operating Modes ...................................................................................... 485 Internal Reference Voltage and ACREFCTL Field Values ................................................. 485 Analog Comparators Register Map ................................................................................. 487 Signals by Pin Number ................................................................................................... 496 Signals by Signal Name ................................................................................................. 500 Signals by Function, Except for GPIO ............................................................................. 504 GPIO Pins and Alternate Functions ................................................................................. 508 Temperature Characteristics ........................................................................................... 510 Thermal Characteristics ................................................................................................. 510 Maximum Ratings .......................................................................................................... 511 Recommended DC Operating Conditions ........................................................................ 511 LDO Regulator Characteristics ....................................................................................... 512 June 14, 2007 11 Luminary Micro Confidential-Advance Product Information Table of Contents Table 22-4. Table 22-5. Table 22-6. Table 22-7. Table 22-8. Table 22-9. Table 22-10. Table 22-11. Table 22-12. Table 22-13. Table 22-14. Table 22-15. Table 22-16. Table 22-17. Table 22-18. Table 22-19. Table 22-20. Table 22-21. Table 22-22. Table 22-23. Table 22-24. Table 22-25. Table 22-26. Table 24-1. Flash Memory Characteristics ........................................................................................ 513 Phase Locked Loop (PLL) Characteristics ....................................................................... 513 Clock Characteristics ..................................................................................................... 513 Crystal Characteristics ................................................................................................... 514 Temperature Sensor Characteristics ............................................................................... 514 ADC Characteristics ....................................................................................................... 514 Analog Comparator Characteristics ................................................................................. 515 Analog Comparator Voltage Reference Characteristics .................................................... 515 2 I C Characteristics ......................................................................................................... 515 100BASE-TX Transmitter Characteristics ........................................................................ 516 100BASE-TX Transmitter Characteristics (informative) ..................................................... 516 100BASE-TX Receiver Characteristics ............................................................................ 516 10BASE-T Transmitter Characteristics ............................................................................ 516 10BASE-T Transmitter Characteristics (informative) ......................................................... 517 10BASE-T Receiver Characteristics ................................................................................ 517 Isolation Transformers ................................................................................................... 517 Ethernet Reference Crystal ............................................................................................ 518 External XTLP Oscillator Characteristics ......................................................................... 518 Hibernation Module Characteristics ................................................................................. 519 SSI Characteristics ........................................................................................................ 519 JTAG Characteristics ..................................................................................................... 521 GPIO Characteristics ..................................................................................................... 523 Reset Characteristics ..................................................................................................... 523 Part Ordering Information ............................................................................................... 527 12 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller List of Registers System Control .............................................................................................................................. 57 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Device Identification 0 (DID0), offset 0x000 ....................................................................... 65 Brown-Out Reset Control (PBORCTL), offset 0x030 .......................................................... 67 LDO Power Control (LDOPCTL), offset 0x034 ................................................................... 68 Raw Interrupt Status (RIS), offset 0x050 ........................................................................... 69 Interrupt Mask Control (IMC), offset 0x054 ........................................................................ 70 Masked Interrupt Status and Clear (MISC), offset 0x058 .................................................... 71 Reset Cause (RESC), offset 0x05C .................................................................................. 72 Run-Mode Clock Configuration (RCC), offset 0x060 .......................................................... 73 XTAL to PLL Translation (PLLCFG), offset 0x064 .............................................................. 77 Run-Mode Clock Configuration 2 (RCC2), offset 0x070 ...................................................... 78 Deep Sleep Clock Configuration (DSLPCLKCFG), offset 0x144 .......................................... 80 Device Identification 1 (DID1), offset 0x004 ....................................................................... 81 Device Capabilities 0 (DC0), offset 0x008 ......................................................................... 83 Device Capabilities 1 (DC1), offset 0x010 ......................................................................... 84 Device Capabilities 2 (DC2), offset 0x014 ......................................................................... 86 Device Capabilities 3 (DC3), offset 0x018 ......................................................................... 88 Device Capabilities 4 (DC4), offset 0x01C ......................................................................... 90 Run Mode Clock Gating Control Register 0 (RCGC0), offset 0x100 .................................... 91 Sleep Mode Clock Gating Control Register 0 (SCGC0), offset 0x110 .................................. 93 Deep Sleep Mode Clock Gating Control Register 0 (DCGC0), offset 0x120 ......................... 95 Run Mode Clock Gating Control Register 1 (RCGC1), offset 0x104 .................................... 97 Sleep Mode Clock Gating Control Register 1 (SCGC1), offset 0x114 .................................. 99 Deep Sleep Mode Clock Gating Control Register 1 (DCGC1), offset 0x124 ....................... 101 Run Mode Clock Gating Control Register 2 (RCGC2), offset 0x108 ................................... 103 Sleep Mode Clock Gating Control Register 2 (SCGC2), offset 0x118 ................................. 105 Deep Sleep Mode Clock Gating Control Register 2 (DCGC2), offset 0x128 ....................... 107 Software Reset Control 0 (SRCR0), offset 0x040 ............................................................. 109 Software Reset Control 1 (SRCR1), offset 0x044 ............................................................. 110 Software Reset Control 2 (SRCR2), offset 0x048 ............................................................. 112 Hibernation Module ..................................................................................................................... 113 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Hibernation RTC Counter (HIBRTCC), offset 0x000 ......................................................... Hibernation RTC Match 0 (HIBRTCM0), offset 0x004 ....................................................... Hibernation RTC Match 1 (HIBRTCM1), offset 0x008 ....................................................... Hibernation RTC Load (HIBRTCLD), offset 0x00C ........................................................... Hibernation Control (HIBCTL), offset 0x010 ..................................................................... Hibernation Interrupt Mask (HIBIM), offset 0x014 ............................................................. Hibernation Raw Interrupt Status (HIBRIS), offset 0x018 .................................................. Hibernation Masked Interrupt Status (HIBMIS), offset 0x01C ............................................ Hibernation Interrupt Clear (HIBIC), offset 0x020 ............................................................. Hibernation RTC Trim (HIBRTCT), offset 0x024 ............................................................... Hibernation Data (HIBDATA), offset 0x030-0x12C ............................................................ 119 120 121 122 123 125 126 127 128 129 130 Internal Memory ........................................................................................................................... 131 Register 1: Register 2: Flash Memory Address (FMA), offset 0x000 .................................................................... 136 Flash Memory Data (FMD), offset 0x004 ......................................................................... 137 June 14, 2007 13 Luminary Micro Confidential-Advance Product Information Table of Contents Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Flash Memory Control (FMC), offset 0x008 ..................................................................... Flash Controller Raw Interrupt Status (FCRIS), offset 0x00C ............................................ Flash Controller Interrupt Mask (FCIM), offset 0x010 ........................................................ Flash Controller Masked Interrupt Status and Clear (FCMISC), offset 0x014 ..................... USec Reload (USECRL), offset 0x140 ............................................................................ Flash Memory Protection Read Enable 0 (FMPRE0), offset 0x130 and 0x200 ................... Flash Memory Protection Program Enable 0 (FMPPE0), offset 0x134 and 0x400 ............... User Debug (USER_DBG), offset 0x1D0 ......................................................................... User Register 0 (USER_REG0), offset 0x1E0 .................................................................. User Register 1 (USER_REG1), offset 0x1E4 .................................................................. Flash Memory Protection Read Enable 1 (FMPRE1), offset 0x204 .................................... Flash Memory Protection Read Enable 2 (FMPRE2), offset 0x208 .................................... Flash Memory Protection Read Enable 3 (FMPRE3), offset 0x20C ................................... Flash Memory Protection Program Enable 1 (FMPPE1), offset 0x404 ............................... Flash Memory Protection Program Enable 2 (FMPPE2), offset 0x408 ............................... Flash Memory Protection Program Enable 3 (FMPPE3), offset 0x40C ............................... 138 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 GPIO .............................................................................................................................................. 155 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 31: GPIO Data (GPIODATA), offset 0x000 ............................................................................ 162 GPIO Direction (GPIODIR), offset 0x400 ......................................................................... 163 GPIO Interrupt Sense (GPIOIS), offset 0x404 .................................................................. 164 GPIO Interrupt Both Edges (GPIOIBE), offset 0x408 ........................................................ 165 GPIO Interrupt Event (GPIOIEV), offset 0x40C ................................................................ 166 GPIO Interrupt Mask (GPIOIM), offset 0x410 ................................................................... 167 GPIO Raw Interrupt Status (GPIORIS), offset 0x414 ........................................................ 168 GPIO Masked Interrupt Status (GPIOMIS), offset 0x418 ................................................... 169 GPIO Interrupt Clear (GPIOICR), offset 0x41C ................................................................ 170 GPIO Alternate Function Select (GPIOAFSEL), offset 0x420 ............................................ 171 GPIO 2-mA Drive Select (GPIODR2R), offset 0x500 ........................................................ 173 GPIO 4-mA Drive Select (GPIODR4R), offset 0x504 ........................................................ 174 GPIO 8-mA Drive Select (GPIODR8R), offset 0x508 ........................................................ 175 GPIO Open Drain Select (GPIOODR), offset 0x50C ......................................................... 176 GPIO Pull-Up Select (GPIOPUR), offset 0x510 ................................................................ 177 GPIO Pull-Down Select (GPIOPDR), offset 0x514 ........................................................... 178 GPIO Slew Rate Control Select (GPIOSLR), offset 0x518 ................................................ 179 GPIO Digital Enable (GPIODEN), offset 0x51C ................................................................ 180 GPIO Lock (GPIOLOCK), offset 0x520 ............................................................................ 181 GPIO Commit (GPIOCR), offset 0x524 ............................................................................ 182 GPIO Peripheral Identification 4 (GPIOPeriphID4), offset 0xFD0 ....................................... 184 GPIO Peripheral Identification 5 (GPIOPeriphID5), offset 0xFD4 ....................................... 185 GPIO Peripheral Identification 6 (GPIOPeriphID6), offset 0xFD8 ....................................... 186 GPIO Peripheral Identification 7 (GPIOPeriphID7), offset 0xFDC ...................................... 187 GPIO Peripheral Identification 0 (GPIOPeriphID0), offset 0xFE0 ....................................... 188 GPIO Peripheral Identification 1(GPIOPeriphID1), offset 0xFE4 ........................................ 189 GPIO Peripheral Identification 2 (GPIOPeriphID2), offset 0xFE8 ....................................... 190 GPIO Peripheral Identification 3 (GPIOPeriphID3), offset 0xFEC ...................................... 191 GPIO PrimeCell Identification 0 (GPIOPCellID0), offset 0xFF0 .......................................... 192 GPIO PrimeCell Identification 1 (GPIOPCellID1), offset 0xFF4 .......................................... 193 GPIO PrimeCell Identification 2 (GPIOPCellID2), offset 0xFF8 .......................................... 194 14 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 32: GPIO PrimeCell Identification 3 (GPIOPCellID3), offset 0xFFC ......................................... 195 Timers ........................................................................................................................................... 196 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: GPTM Configuration (GPTMCFG), offset 0x000 .............................................................. GPTM TimerA Mode (GPTMTAMR), offset 0x004 ............................................................ GPTM TimerB Mode (GPTMTBMR), offset 0x008 ............................................................ GPTM Control (GPTMCTL), offset 0x00C ........................................................................ GPTM Interrupt Mask (GPTMIMR), offset 0x018 .............................................................. GPTM Raw Interrupt Status (GPTMRIS), offset 0x01C ..................................................... GPTM Masked Interrupt Status (GPTMMIS), offset 0x020 ................................................ GPTM Interrupt Clear (GPTMICR), offset 0x024 .............................................................. GPTM TimerA Interval Load (GPTMTAILR), offset 0x028 ................................................. GPTM TimerB Interval Load (GPTMTBILR), offset 0x02C ................................................ GPTM TimerA Match (GPTMTAMATCHR), offset 0x030 ................................................... GPTM TimerB Match (GPTMTBMATCHR), offset 0x034 .................................................. GPTM TimerA Prescale (GPTMTAPR), offset 0x038 ........................................................ GPTM TimerB Prescale (GPTMTBPR), offset 0x03C ....................................................... GPTM TimerA Prescale Match (GPTMTAPMR), offset 0x040 ........................................... GPTM TimerB Prescale Match (GPTMTBPMR), offset 0x044 ........................................... GPTM TimerA (GPTMTAR), offset 0x048 ........................................................................ GPTM TimerB (GPTMTBR), offset 0x04C ....................................................................... 208 209 210 211 213 215 216 217 219 220 221 222 223 224 225 226 227 228 Watchdog Timer ........................................................................................................................... 229 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Watchdog Load (WDTLOAD), offset 0x000 ...................................................................... Watchdog Value (WDTVALUE), offset 0x004 ................................................................... Watchdog Control (WDTCTL), offset 0x008 ..................................................................... Watchdog Interrupt Clear (WDTICR), offset 0x00C .......................................................... Watchdog Raw Interrupt Status (WDTRIS), offset 0x010 .................................................. Watchdog Masked Interrupt Status (WDTMIS), offset 0x014 ............................................. Watchdog Test (WDTTEST), offset 0x418 ....................................................................... Watchdog Lock (WDTLOCK), offset 0xC00 ..................................................................... Watchdog Peripheral Identification 4 (WDTPeriphID4), offset 0xFD0 ................................. Watchdog Peripheral Identification 5 (WDTPeriphID5), offset 0xFD4 ................................. Watchdog Peripheral Identification 6 (WDTPeriphID6), offset 0xFD8 ................................. Watchdog Peripheral Identification 7 (WDTPeriphID7), offset 0xFDC ................................ Watchdog Peripheral Identification 0 (WDTPeriphID0), offset 0xFE0 ................................. Watchdog Peripheral Identification 1 (WDTPeriphID1), offset 0xFE4 ................................. Watchdog Peripheral Identification 2 (WDTPeriphID2), offset 0xFE8 ................................. Watchdog Peripheral Identification 3 (WDTPeriphID3), offset 0xFEC ................................. Watchdog PrimeCell Identification 0 (WDTPCellID0), offset 0xFF0 .................................... Watchdog PrimeCell Identification 1 (WDTPCellID1), offset 0xFF4 .................................... Watchdog PrimeCell Identification 2 (WDTPCellID2), offset 0xFF8 .................................... Watchdog PrimeCell Identification 3 (WDTPCellID3 ), offset 0xFFC .................................. 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 ADC ............................................................................................................................................... 252 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: ADC Active Sample Sequencer (ADCACTSS), offset 0x000 ............................................. 259 ADC Raw Interrupt Status (ADCRIS), offset 0x004 ........................................................... 260 ADC Interrupt Mask (ADCIM), offset 0x008 ..................................................................... 261 ADC Interrupt Status and Clear (ADCISC), offset 0x00C .................................................. 262 ADC Overflow Status (ADCOSTAT), offset 0x010 ............................................................ 263 ADC Event Multiplexer Select (ADCEMUX), offset 0x014 ................................................. 264 June 14, 2007 15 Luminary Micro Confidential-Advance Product Information Table of Contents Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: ADC Underflow Status (ADCUSTAT), offset 0x018 ........................................................... ADC Sample Sequencer Priority (ADCSSPRI), offset 0x020 ............................................. ADC Processor Sample Sequence Initiate (ADCPSSI), offset 0x028 ................................. ADC Sample Averaging Control (ADCSAC), offset 0x030 ................................................. ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0), offset 0x040 ............... ADC Sample Sequence Control 0 (ADCSSCTL0), offset 0x044 ........................................ ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0), offset 0x048 ................................ ADC Sample Sequence Result FIFO 1 (ADCSSFIFO1), offset 0x068 ................................ ADC Sample Sequence Result FIFO 2 (ADCSSFIFO2), offset 0x088 ................................ ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0), offset 0x04C ............................. ADC Sample Sequence FIFO 1 Status (ADCSSFSTAT1), offset 0x06C ............................. ADC Sample Sequence FIFO 2 Status (ADCSSFSTAT2), offset 0x08C ............................. ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1), offset 0x060 ............... ADC Sample Sequence Control 1 (ADCSSCTL1), offset 0x064 ........................................ ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2), offset 0x080 ............... ADC Sample Sequence Control 2 (ADCSSCTL2), offset 0x084 ........................................ ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3), offset 0x0A0 ............... ADC Sample Sequence Control 3 (ADCSSCTL3), offset 0x0A4 ........................................ ADC Sample Sequence Result FIFO 3 (ADCSSFIFO3), offset 0x0A8 ............................... ADC Sample Sequence FIFO 3 Status (ADCSSFSTAT3), offset 0x0AC ............................ ADC Test Mode Loopback (ADCTMLB), offset 0x100 ....................................................... 265 266 267 268 269 271 273 273 273 274 274 274 275 276 277 278 279 280 281 282 283 UART ............................................................................................................................................. 285 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: UART Data (UARTDR), offset 0x000 ............................................................................... UART Receive Status/Error Clear (UARTRSR/UARTECR), offset 0x004 ........................... UART Flag (UARTFR), offset 0x018 ................................................................................ UART IrDA Low-Power Register (UARTILPR), offset 0x020 ............................................. UART Integer Baud-Rate Divisor (UARTIBRD), offset 0x024 ............................................ UART Fractional Baud-Rate Divisor (UARTFBRD), offset 0x028 ....................................... UART Line Control (UARTLCRH), offset 0x02C ............................................................... UART Control (UARTCTL), offset 0x030 ......................................................................... UART Interrupt FIFO Level Select (UARTIFLS), offset 0x034 ........................................... UART Interrupt Mask (UARTIM), offset 0x038 ................................................................. UART Raw Interrupt Status (UARTRIS), offset 0x03C ...................................................... UART Masked Interrupt Status (UARTMIS), offset 0x040 ................................................. UART Interrupt Clear (UARTICR), offset 0x044 ............................................................... UART Peripheral Identification 4 (UARTPeriphID4), offset 0xFD0 ..................................... UART Peripheral Identification 5 (UARTPeriphID5), offset 0xFD4 ..................................... UART Peripheral Identification 6 (UARTPeriphID6), offset 0xFD8 ..................................... UART Peripheral Identification 7 (UARTPeriphID7), offset 0xFDC ..................................... UART Peripheral Identification 0 (UARTPeriphID0), offset 0xFE0 ...................................... UART Peripheral Identification 1 (UARTPeriphID1), offset 0xFE4 ...................................... UART Peripheral Identification 2 (UARTPeriphID2), offset 0xFE8 ...................................... UART Peripheral Identification 3 (UARTPeriphID3), offset 0xFEC ..................................... UART PrimeCell Identification 0 (UARTPCellID0), offset 0xFF0 ........................................ UART PrimeCell Identification 1 (UARTPCellID1), offset 0xFF4 ........................................ UART PrimeCell Identification 2 (UARTPCellID2), offset 0xFF8 ........................................ UART PrimeCell Identification 3 (UARTPCellID3), offset 0xFFC ........................................ 16 293 295 297 299 300 301 302 304 306 307 309 310 311 313 314 315 316 317 318 319 320 321 322 323 324 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller SSI ................................................................................................................................................. 325 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: SSI Control 0 (SSICR0), offset 0x000 .............................................................................. SSI Control 1 (SSICR1), offset 0x004 .............................................................................. SSI Data (SSIDR), offset 0x008 ...................................................................................... SSI Status (SSISR), offset 0x00C ................................................................................... SSI Clock Prescale (SSICPSR), offset 0x010 .................................................................. SSI Interrupt Mask (SSIIM), offset 0x014 ......................................................................... SSI Raw Interrupt Status (SSIRIS), offset 0x018 .............................................................. SSI Masked Interrupt Status (SSIMIS), offset 0x01C ........................................................ SSI Interrupt Clear (SSIICR), offset 0x020 ....................................................................... SSI Peripheral Identification 4 (SSIPeriphID4), offset 0xFD0 ............................................. SSI Peripheral Identification 5 (SSIPeriphID5), offset 0xFD4 ............................................. SSI Peripheral Identification 6 (SSIPeriphID6), offset 0xFD8 ............................................. SSI Peripheral Identification 7 (SSIPeriphID7), offset 0xFDC ............................................ SSI Peripheral Identification 0 (SSIPeriphID0), offset 0xFE0 ............................................. SSI Peripheral Identification 1 (SSIPeriphID1), offset 0xFE4 ............................................. SSI Peripheral Identification 2 (SSIPeriphID2), offset 0xFE8 ............................................. SSI Peripheral Identification 3 (SSIPeriphID3), offset 0xFEC ............................................ SSI PrimeCell Identification 0 (SSIPCellID0), offset 0xFF0 ............................................... SSI PrimeCell Identification 1 (SSIPCellID1), offset 0xFF4 ............................................... SSI PrimeCell Identification 2 (SSIPCellID2), offset 0xFF8 ............................................... SSI PrimeCell Identification 3 (SSIPCellID3), offset 0xFFC ............................................... 337 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 2 Inter-Integrated Circuit (I C) Interface ........................................................................................ 359 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: 2 I C Master Slave Address (I2CMSA), offset 0x000 ........................................................... 2 I C Master Control/Status (I2CMCS), offset 0x004 ........................................................... 2 I C Master Data (I2CMDR), offset 0x008 ......................................................................... 2 I C Master Timer Period (I2CMTPR), offset 0x00C ........................................................... 2 I C Master Interrupt Mask (I2CMIMR), offset 0x010 ......................................................... 2 I C Master Raw Interrupt Status (I2CMRIS), offset 0x014 ................................................. 2 I C Master Masked Interrupt Status (I2CMMIS), offset 0x018 ........................................... 2 I C Master Interrupt Clear (I2CMICR), offset 0x01C ......................................................... 2 I C Master Configuration (I2CMCR), offset 0x020 ............................................................ 2 I C Slave Own Address (I2CSOAR), offset 0x000 ............................................................ 2 I C Slave Control/Status (I2CSCSR), offset 0x004 ........................................................... 2 I C Slave Data (I2CSDR), offset 0x008 ........................................................................... 2 I C Slave Interrupt Mask (I2CSIMR), offset 0x00C ........................................................... 2 I C Slave Raw Interrupt Status (I2CSRIS), offset 0x010 ................................................... 2 I C Slave Masked Interrupt Status (I2CSMIS), offset 0x014 .............................................. 2 I C Slave Interrupt Clear (I2CSICR), offset 0x018 ............................................................ 373 374 378 379 380 381 382 383 384 386 387 389 390 391 392 393 CAN ............................................................................................................................................... 394 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: CAN Control (CANCTL), offset 0x000 ............................................................................. 408 CAN Status (CANSTS), offset 0x004 ............................................................................... 410 CAN Error Counter (CANERR), offset 0x008 ................................................................... 413 CAN Bit Timing (CANBIT), offset 0x00C .......................................................................... 414 CAN Interrupt (CANINT), offset 0x010 ............................................................................. 416 CAN Test (CANTST), offset 0x014 .................................................................................. 417 CAN Baud Rate Prescalar Extension (CANBRPE), offset 0x018 ....................................... 419 June 14, 2007 17 Luminary Micro Confidential-Advance Product Information Table of Contents Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Register 30: Register 31: Register 32: Register 33: Register 34: Register 35: Register 36: Register 37: CAN IF1 Command Request (CANIF1CRQ), offset 0x020 ................................................ 420 CAN IF2 Command Request (CANIF2CRQ), offset 0x080 ................................................ 420 CAN IF1 Command Mask (CANIF1CMSK), offset 0x024 .................................................. 421 CAN IF2 Command Mask (CANIF2CMSK), offset 0x084 .................................................. 421 CAN IF1 Mask 1 (CANIF1MSK1), offset 0x028 ................................................................ 424 CAN IF2 Mask 1 (CANIF2MSK1), offset 0x088 ................................................................ 424 CAN IF1 Mask 2 (CANIF1MSK2), offset 0x02C ................................................................ 425 CAN IF2 Mask 2 (CANIF2MSK2), offset 0x08C ................................................................ 425 CAN IF1 Arbitration 1 (CANIF1ARB1), offset 0x030 ......................................................... 426 CAN IF2 Arbitration 1 (CANIF2ARB1), offset 0x090 ......................................................... 426 CAN IF1 Arbitration 2 (CANIF1ARB2), offset 0x034 ......................................................... 427 CAN IF2 Arbitration 2 (CANIF2ARB2), offset 0x094 ......................................................... 427 CAN IF1 Message Control (CANIF1MCTL), offset 0x038 .................................................. 428 CAN IF2 Message Control (CANIF2MCTL), offset 0x098 .................................................. 428 CAN IF1 Data A1 (CANIF1DA1), offset 0x03C ................................................................. 430 CAN IF2 Data A1 (CANIF2DA1), offset 0x09C ................................................................. 430 CAN IF1 Data A2 (CANIF1DA2), offset 0x040 ................................................................. 431 CAN IF2 Data A2 (CANIF2DA2), offset 0x0A0 ................................................................. 431 CAN IF1 Data B1 (CANIF1DB1), offset 0x044 ................................................................. 432 CAN IF2 Data B1 (CANIF2DB1), offset 0x0A4 ................................................................. 432 CAN IF1 Data B2 (CANIF1DB2), offset 0x048 ................................................................. 433 CAN IF2 Data B2 (CANIF2DB2), offset 0x0A8 ................................................................. 433 CAN Transmission Request 1 (CANTXRQ1), offset 0x100 ................................................ 434 CAN Transmission Request 2 (CANTXRQ2), offset 0x104 ................................................ 434 CAN New Data 1 (CANNWDA1), offset 0x120 ................................................................. 435 CAN New Data 2 (CANNWDA2), offset 0x124 ................................................................. 435 CAN Message 1 Interrupt Pending (CANMSG1INT), offset 0x140 ..................................... 436 CAN Message 2 Interrupt Pending (CANMSG2INT), offset 0x144 ..................................... 436 CAN Message 1 Valid (CANMSG1VAL), offset 0x160 ....................................................... 437 CAN Message 2 Valid (CANMSG2VAL), offset 0x164 ....................................................... 437 Ethernet ........................................................................................................................................ 438 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Register 11: Register 12: Register 13: Register 14: Register 15: Register 16: Register 17: Ethernet MAC Raw Interrupt Status (MACRIS), offset 0x000 ............................................ Ethernet MAC Interrupt Acknowledge (MACIACK), offset 0x000 ....................................... Ethernet MAC Interrupt Mask (MACIM), offset 0x004 ....................................................... Ethernet MAC Receive Control (MACRCTL), offset 0x008 ................................................ Ethernet MAC Transmit Control (MACTCTL), offset 0x00C ............................................... Ethernet MAC Data (MACDATA), offset 0x010 ................................................................. Ethernet MAC Individual Address 0 (MACIA0), offset 0x014 ............................................. Ethernet MAC Individual Address 1 (MACIA1), offset 0x018 ............................................. Ethernet MAC Threshold (MACTHR), offset 0x01C .......................................................... Ethernet MAC Management Control (MACMCTL), offset 0x020 ........................................ Ethernet MAC Management Divider (MACMDV), offset 0x024 .......................................... Ethernet MAC Management Address (MACMADD), offset 0x028 ...................................... Ethernet MAC Management Transmit Data (MACMTXD), offset 0x02C ............................. Ethernet MAC Management Receive Data (MACMRXD), offset 0x030 .............................. Ethernet MAC Number of Packets (MACNP), offset 0x034 ............................................... Ethernet MAC Transmission Request (MACTR), offset 0x038 ........................................... Ethernet PHY Management Register 0 – Control (MR0), offset 0x00 ................................. 18 447 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 18: Register 19: Register 20: Register 21: Register 22: Register 23: Register 24: Register 25: Register 26: Register 27: Register 28: Register 29: Ethernet PHY Management Register 1 – Status (MR1), offset 0x01 .................................. Ethernet PHY Management Register 2 – PHY Identifier 1 (MR2), offset 0x02 .................... Ethernet PHY Management Register 3 – PHY Identifier 2 (MR3), offset 0x03 .................... Ethernet PHY Management Register 4 – Auto-Negotiation Advertisement (MR4), offset 0x04 ............................................................................................................................. Ethernet PHY Management Register 5 – Auto-Negotiation Link Partner Base Page Ability (MR5), offset 0x05 ......................................................................................................... Ethernet PHY Management Register 6 – Auto-Negotiation Expansion (MR6), offset 0x06 ............................................................................................................................. Ethernet PHY Management Register 16 – Vendor-Specific (MR16), offset 0x10 ................. Ethernet PHY Management Register 17 – Interrupt Control/Status (MR17), offset 0x11 ...... Ethernet PHY Management Register 18 – Diagnostic (MR18), offset 0x12 ........................ Ethernet PHY Management Register 19 – Transceiver Control (MR19), offset 0x13 ........... Ethernet PHY Management Register 23 – LED Configuration (MR23), offset 0x17 ............. Ethernet PHY Management Register 24 –MDI/MDIX Control (MR24), offset 0x18 .............. 466 468 469 470 472 473 474 476 478 479 480 481 Analog Comparators ................................................................................................................... 482 Register 1: Register 2: Register 3: Register 4: Register 5: Register 6: Register 7: Register 8: Register 9: Register 10: Analog Comparator Masked Interrupt Status (ACMIS), offset 0x00 .................................... Analog Comparator Raw Interrupt Status (ACRIS), offset 0x04 ......................................... Analog Comparator Interrupt Enable (ACINTEN), offset 0x08 ........................................... Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x10 ......................... Analog Comparator Status 0 (ACSTAT0), offset 0x20 ....................................................... Analog Comparator Status 1 (ACSTAT1), offset 0x40 ....................................................... Analog Comparator Status 2 (ACSTAT2), offset 0x60 ....................................................... Analog Comparator Control 0 (ACCTL0), offset 0x24 ....................................................... Analog Comparator Control 1 (ACCTL1), offset 0x44 ....................................................... Analog Comparator Control 2 (ACCTL2), offset 0x64 ...................................................... June 14, 2007 488 489 490 491 492 492 492 493 493 493 19 Luminary Micro Confidential-Advance Product Information About This Document About This Document This data sheet provides reference information for the LM3S8938 microcontroller, describing the functional blocks of the system-on-chip (SoC) device designed around the ARM® Cortex™-M3 core. Audience This manual is intended for system software developers, hardware designers, and application developers. About This Manual This document is organized into sections that correspond to each major feature. Related Documents The following documents are referenced by the data sheet, and available on the documentation CD or from the Luminary Micro web site at www.luminarymicro.com: ■ ARM® Cortex™-M3 Technical Reference Manual ■ ARM® CoreSight Technical Reference Manual ■ ARM® v7-M Architecture Application Level Reference Manual The following related documents are also referenced: ■ IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture This documentation list was current as of publication date. Please check the Luminary Micro web site for additional documentation, including application notes and white papers. Documentation Conventions This document uses the conventions shown in Table 1 on page 20. Table 1. Documentation Conventions Notation Meaning General Register Notation REGISTER APB registers are indicated in uppercase bold. For example, PBORCTL is the Power-On and Brown-Out Reset Control register. If a register name contains a lowercase n, it represents more than one register. For example, SRCRn represents any (or all) of the three Software Reset Control registers: SRCR0, SRCR1 , and SRCR2. bit A single bit in a register. bit field Two or more consecutive and related bits. offset 0xnnn A hexadecimal increment to a register's address, relative to that module's base address as specified in “Memory Map” on page 41. Register N Registers are numbered consecutively throughout the document to aid in referencing them. The register number has no meaning to software. 20 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Notation Meaning reserved Register bits marked reserved are reserved for future use. In most cases, reserved bits are set to 0; however, user software should not rely on the value of a reserved bit. To provide software compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. yy:xx The range of register bits inclusive from xx to yy. For example, 31:15 means bits 15 through 31 in that register. Register Bit/Field Types This value in the register bit diagram indicates whether software running on the controller can change the value of the bit field. RC Software can read this field. The bit or field is cleared by hardware after reading the bit/field. RO Software can read this field. Always write the chip reset value. R/W Software can read or write this field. R/W1C Software can read or write this field. A write of a 0 to a W1C bit does not affect the bit value in the register. A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged. This register type is primarily used for clearing interrupt status bits where the read operation provides the interrupt status and the write of the read value clears only the interrupts being reported at the time the register was read. W1C Software can write this field. A write of a 0 to a W1C bit does not affect the bit value in the register. A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged. A read of the register returns no meaningful data. This register is typically used to clear the corresponding bit in an interrupt register. WO Only a write by software is valid; a read of the register returns no meaningful data. Register Bit/Field Reset Value This value in the register bit diagram shows the bit/field value after any reset, unless noted. 0 Bit cleared to 0 on chip reset. 1 Bit set to 1 on chip reset. - Nondeterministic. Pin/Signal Notation [] Pin alternate function; a pin defaults to the signal without the brackets. pin Refers to the physical connection on the package. signal Refers to the electrical signal encoding of a pin. assert a signal Change the value of the signal from the logically False state to the logically True state. For active High signals, the asserted signal value is 1 (High); for active Low signals, the asserted signal value is 0 (Low). The active polarity (High or Low) is defined by the signal name (see SIGNAL and SIGNAL below). deassert a signal Change the value of the signal from the logically True state to the logically False state. SIGNAL Signal names are in uppercase and in the Courier font. An overbar on a signal name indicates that it is active Low. To assert SIGNAL is to drive it Low; to deassert SIGNAL is to drive it High. SIGNAL Signal names are in uppercase and in the Courier font. An active High signal has no overbar. To assert SIGNAL is to drive it High; to deassert SIGNAL is to drive it Low. Numbers X An uppercase X indicates any of several values is allowed, where X can be any legal pattern. For example, a binary value of 0X00 can be either 0100 or 0000, a hex value of 0xX is 0x0 or 0x1, and so on. 0x Hexadecimal numbers have a prefix of 0x. For example, 0x00FF is the hexadecimal number FF. Binary numbers are indicated with a b suffix, for example, 1011b. Decimal numbers are written without a prefix or suffix. June 14, 2007 21 Luminary Micro Confidential-Advance Product Information Architectural Overview 1 Architectural Overview ® The Luminary Micro Stellaris family of microcontrollers—the first ARM® Cortex™-M3 based controllers—brings high-performance 32-bit computing to cost-sensitive embedded microcontroller applications. These pioneering parts deliver customers 32-bit performance at a cost equivalent to legacy 8- and 16-bit devices, all in a package with a small footprint. ® The Stellaris family offers efficient performance and extensive integration, favorably positioning the device into cost-conscious applications requiring significant control-processing and connectivity ® capabilities. The Stellaris LM3S2000 series, designed for Controller Area Network (CAN) applications, extends the Stellaris family with Bosch CAN networking technology, the golden standard ® in short-haul industrial networks. The Stellaris LM3S2000 series also marks the first integration of ® CAN capabilities with the revolutionary Cortex-M3 core. The Stellaris LM3S6000 series combines both a 10/100 Ethernet Media Access Control (MAC) and Physical (PHY) layer, marking the first time that integrated connectivity is available with an ARM Cortex-M3 MCU and the only integrated 10/100 Ethernet MAC and PHY available in an ARM architecture MCU. The LM3S8938 microcontroller is targeted for industrial applications, including remote monitoring, electronic point-of-sale machines, test and measurement equipment, network appliances and switches, factory automation, HVAC and building control, gaming equipment, motion control, medical instrumentation, and fire and security. For applications requiring extreme conservation of power, the LM3S8938 microcontroller features a Battery-backed Hibernation module to efficiently power down the LM3S8938 to a low-power state during extended periods of inactivity. With a power-up/power-down sequencer, a continuous time counter (RTC), a pair of match registers, an APB interface to the system bus, and dedicated non-volatile memory, the Hibernation module positions the LM3S8938 microcontroller perfectly for battery applications. In addition, the LM3S8938 microcontroller offers the advantages of ARM's widely available development tools, System-on-Chip (SoC) infrastructure IP applications, and a large user community. Additionally, the microcontroller uses ARM's Thumb®-compatible Thumb-2 instruction set to reduce memory requirements and, thereby, cost. Finally, the LM3S8938 microcontroller is code-compatible ® to all members of the extensive Stellaris family; providing flexibility to fit our customers' precise needs. Luminary Micro offers a complete solution to get to market quickly, with evaluation and development boards, white papers and application notes, an easy-to-use peripheral driver library, and a strong support, sales, and distributor network. 1.1 Product Features The LM3S8938 microcontroller includes the following product features: ■ 32-Bit RISC Performance – 32-bit ARM® Cortex™-M3 v7M architecture optimized for small-footprint embedded applications – System timer (SysTick), providing a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism – Thumb®-compatible Thumb-2-only instruction set processor core for high code density – 50-MHz operation 22 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller – Hardware-division and single-cycle-multiplication – Integrated Nested Vectored Interrupt Controller (NVIC) providing deterministic interrupt handling – 34 interrupts with eight priority levels – Memory protection unit (MPU), providing a privileged mode for protected operating system functionality – Unaligned data access, enabling data to be efficiently packed into memory – Atomic bit manipulation (bit-banding), delivering maximum memory utilization and streamlined peripheral control ■ Internal Memory – 256 KB single-cycle flash • User-managed flash block protection on a 2-KB block basis • User-managed flash data programming • User-defined and managed flash-protection block – 64 KB single-cycle SRAM ■ General-Purpose Timers – Four General-Purpose Timer Modules (GPTM), each of which provides two 16-bit timer/counters. Each GPTM can be configured to operate independently as timers or event counters (eight total): as a single 32-bit timer (four total), as one 32-bit Real-Time Clock (RTC) to event capture, for Pulse Width Modulation (PWM), or to trigger analog-to-digital conversions – 32-bit Timer modes • Programmable one-shot timer • Programmable periodic timer • Real-Time Clock when using an external 32.768-KHz clock as the input • User-enabled stalling in periodic and one-shot mode when the controller asserts the CPU Halt flag during debug • ADC event trigger – 16-bit Timer modes • General-purpose timer function with an 8-bit prescaler • Programmable one-shot timer • Programmable periodic timer • User-enabled stalling when the controller asserts CPU Halt flag during debug June 14, 2007 23 Luminary Micro Confidential-Advance Product Information Architectural Overview • ADC event trigger – 16-bit Input Capture modes • Input edge count capture • Input edge time capture – 16-bit PWM mode • Simple PWM mode with software-programmable output inversion of the PWM signal ■ ARM FiRM-compliant Watchdog Timer – 32-bit down counter with a programmable load register – Separate watchdog clock with an enable – Programmable interrupt generation logic with interrupt masking – Lock register protection from runaway software – Reset generation logic with an enable/disable – User-enabled stalling when the controller asserts the CPU Halt flag during debug ■ Controller Area Network (CAN) – Supports CAN protocol version 2.0 part A/B – Bit rates up to 1Mb/s – 32 message objects, each with its own identifier mask – Maskable interrupt – Disable automatic retransmission mode for TTCAN – Programmable loop-back mode for self-test operation ■ 10/100 Ethernet Controller – Conforms to the IEEE 802.3-2002 Specification – Full- and half-duplex for both 100 Mbps and 10 Mbps operation – Integrated 10/100 Mbps Transceiver (PHY) – Automatic MDI/MDI-X cross-over correction – Programmable MAC address – Power-saving and power-down modes ■ Synchronous Serial Interface (SSI) – Master or slave operation 24 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller – Programmable clock bit rate and prescale – Separate transmit and receive FIFOs, 16 bits wide, 8 locations deep – Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces – Programmable data frame size from 4 to 16 bits – Internal loopback test mode for diagnostic/debug testing ■ UART – Three fully programmable 16C550-type UARTs with IrDA support – Separate 16x8 transmit (TX) and 16x12 receive (RX) FIFOs to reduce CPU interrupt service loading – Programmable baud-rate generator with fractional divider – Programmable FIFO length, including 1-byte deep operation providing conventional double-buffered interface – FIFO trigger levels of 1/8, ¼, ½, ¾, and 7/8 – Standard asynchronous communication bits for start, stop, and parity – False-start-bit detection – Line-break generation and detection ■ ADC – Single- and differential-input configurations – Eight 10-bit channels (inputs) when used as single-ended inputs – Sample rate of one million samples/second – Flexible, configurable analog-to-digital conversion – Four programmable sample conversion sequences from one to eight entries long, with corresponding conversion result FIFOs – Each sequence triggered by software or internal event (timers, analog comparators, or GPIO) – On-chip temperature sensor ■ Analog Comparators – Three independent integrated analog comparators – Configurable for output to: drive an output pin, generate an interrupt, or initiate an ADC sample sequence – Compare external pin input to external pin input or to internal programmable voltage reference June 14, 2007 25 Luminary Micro Confidential-Advance Product Information Architectural Overview 2 ■ I C 2 – Two I C modules – Master and slave receive and transmit operation with transmission speed up to 100 Kbps in Standard mode and 400 Kbps in Fast mode – Interrupt generation – Master with arbitration and clock synchronization, multimaster support, and 7-bit addressing mode ■ GPIOs – 3-38 GPIOs, depending on configuration – 5-V-tolerant input/outputs – Programmable interrupt generation as either edge-triggered or level-sensitive – Bit masking in both read and write operations through address lines – Can initiate an ADC sample sequence – Programmable control for GPIO pad configuration: • Weak pull-up or pull-down resistors • 2-mA, 4-mA, and 8-mA pad drive • Slew rate control for the 8-mA drive • Open drain enables • Digital input enables ■ Power – On-chip Low Drop-Out (LDO) voltage regulator, with programmable output user-adjustable from 2.25 V to 2.75 V – Hibernation module handles the power-up/down 3.3 V sequencing and control for the core digital logic and analog circuits – Low-power options on controller: Sleep and Deep-sleep modes – Low-power options for peripherals: software controls shutdown of individual peripherals – User-enabled LDO unregulated voltage detection and automatic reset – 3.3-V supply brown-out detection and reporting via interrupt or reset ■ Flexible Reset Sources – Power-on reset (POR) 26 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller – Reset pin assertion – Brown-out (BOR) detector alerts to system power drops – Software reset – Watchdog timer reset – Internal low drop-out (LDO) regulator output goes unregulated ■ Additional Features – Six reset sources – Programmable clock source control – Clock gating to individual peripherals for power savings – IEEE 1149.1-1990 compliant Test Access Port (TAP) controller – Debug access via JTAG and Serial Wire interfaces – Full JTAG boundary scan ■ Industrial-range 100-pin RoHS-compliant LQFP package 1.2 Target Applications ■ Remote monitoring ■ Electronic point-of-sale (POS) machines ■ Test and measurement equipment ■ Network appliances and switches ■ Factory automation ■ HVAC and building control ■ Gaming equipment ■ Motion control ■ Medical instrumentation ■ Fire and security ■ Power and energy ■ Transportation 1.3 High-Level Block Diagram Figure 1-1 on page 28 shows the features on the Stellaris® Fury-class family of devices. June 14, 2007 27 Luminary Micro Confidential-Advance Product Information Architectural Overview Figure 1-1. Stellaris® Fury-class High-Level Block Diagram 32 JTAG 256 KB Flash NVIC ARM® Cortex™-M3 SWD 50 MHz 32 64 KB SRAM 3 UARTs Systick Timer 2 SSI/SPI 10/100 Ethernet MAC + PHY 4 Timer/PWM/CCP Each 32-bit or 2x16-bit Watchdog Timer SYSTEM SERIAL INTERFACES Clocks, Reset System Control 2 CAN GPIOs 2 2 I C 1.4 2 Quadrature Encoder Inputs 6 PWM Outputs Timer Battery-Backed Hibernate LDO Voltage Regulator 3 Analog Comparators Comparators PWM Generator PWM Interrupt Dead-Band Generator 10-bit ADC 8 channel 1 Msps ANALOG MOTION CONTROL R T C Temp Sensor Functional Overview The following sections provide an overview of the features of the LM3S8938 microcontroller. The page number in parenthesis indicates where that feature is discussed in detail. Ordering and support information can be found in “Ordering and Contact Information” on page 527. 28 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 1.4.1 ARM Cortex™-M3 1.4.1.1 Processor Core (see page 35) ® All members of the Stellaris product family, including the LM3S8938 microcontroller, are designed around an ARM Cortex™-M3 processor core. The ARM Cortex-M3 processor provides the core for a high-performance, low-cost platform that meets the needs of minimal memory implementation, reduced pin count, and low-power consumption, while delivering outstanding computational performance and exceptional system response to interrupts. “ARM Cortex-M3 Processor Core” on page 35 provides an overview of the ARM core; the core is detailed in the ARM® Cortex™-M3 Technical Reference Manual. 1.4.1.2 System Timer (SysTick) Cortex-M3 includes an integrated system timer, SysTick. SysTick provides a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter can be used in several different ways, for example: ■ An RTOS tick timer which fires at a programmable rate (for example, 100 Hz) and invokes a SysTick routine. ■ A high-speed alarm timer using the system clock. ■ A variable rate alarm or signal timer—the duration is range-dependent on the reference clock used and the dynamic range of the counter. ■ A simple counter. Software can use this to measure time to completion and time used. ■ An internal clock source control based on missing/meeting durations. The COUNTFLAG bit-field in the control and status register can be used to determine if an action completed within a set duration, as part of a dynamic clock management control loop. 1.4.1.3 Nested Vectored Interrupt Controller (NVIC) The LM3S8938 controller includes the ARM Nested Vectored Interrupt Controller (NVIC) on the ARM Cortex-M3 core. The NVIC and Cortex-M3 prioritize and handle all exceptions. All exceptions are handled in Handler Mode. The processor state is automatically stored to the stack on an exception, and automatically restored from the stack at the end of the Interrupt Service Routine (ISR). The vector is fetched in parallel to the state saving, which enables efficient interrupt entry. The processor supports tail-chaining, which enables back-to-back interrupts to be performed without the overhead of state saving and restoration. Software can set eight priority levels on 7 exceptions (system handlers) and 34 interrupts. “Interrupts” on page 43 provides an overview of the NVIC controller and the interrupt map. Exceptions and interrupts are detailed in the ARM® Cortex™-M3 Technical Reference Manual. 1.4.2 Motor Control Peripherals To enhance motor control, the LM3S8938 controller features Pulse Width Modulation (PWM) outputs. 1.4.2.1 PWM (see page 202) Pulse width modulation (PWM) is a powerful technique for digitally encoding analog signal levels. High-resolution counters are used to generate a square wave, and the duty cycle of the square wave is modulated to encode an analog signal. Typical applications include switching power supplies and motor control. June 14, 2007 29 Luminary Micro Confidential-Advance Product Information Architectural Overview On the LM3S8938, PWM motion control functionality can be achieved through the motion control features of the general-purpose timers (using the CCP pins). CCP Pins (see page 202) The General-Purpose Timer Module's CCP (Capture Compare PWM) pins are software programmable to support a simple PWM mode with a software-programmable output inversion of the PWM signal. 1.4.3 Serial Communications Peripherals The LM3S8938 controller supports both asynchronous and synchronous serial communications with: ■ Three fully programmable 16C550-type UARTs ■ One SSI module 2 ■ Two I C modules ■ One CAN unit 1.4.3.1 UART (see page 285) A Universal Asynchronous Receiver/Transmitter (UART) is an integrated circuit used for RS-232C serial communications, containing a transmitter (parallel-to-serial converter) and a receiver (serial-to-parallel converter), each clocked separately. The LM3S8938 controller includes three fully programmable 16C550-type UARTs that support data transfer speeds up to 460.8 Kbps. In addition, each UART is capable of supporting IrDA. (Although similar in functionality to a 16C550 UART, it is not register-compatible.) Separate 16x8 transmit (TX) and 16x12 receive (RX) FIFOs reduce CPU interrupt service loading. The UART can generate individually masked interrupts from the RX, TX, modem status, and error conditions. The module provides a single combined interrupt when any of the interrupts are asserted and are unmasked. 1.4.3.2 SSI (see page 325) Synchronous Serial Interface (SSI) is a four-wire bi-directional communications interface. The LM3S8938 controller includes one SSI module that provides the functionality for synchronous serial communications with peripheral devices, and can be configured to use the Freescale SPI, MICROWIRE , or TI synchronous serial interface frame formats. The size of the data frame is also configurable, and can be set between 4 and 16 bits, inclusive. The SSI module performs serial-to-parallel conversion on data received from a peripheral device, and parallel-to-serial conversion on data transmitted to a peripheral device. The TX and RX paths are buffered with internal FIFOs, allowing up to eight 16-bit values to be stored independently. The SSI module can be configured as either a master or slave device. As a slave device, the SSI module can also be configured to disable its output, which allows a master device to be coupled with multiple slave devices. The SSI module also includes a programmable bit rate clock divider and prescaler to generate the output serial clock derived from the SSI module's input clock. Bit rates are generated based on the input clock and the maximum bit rate is determined by the connected peripheral. 30 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 1.4.3.3 2 I C(see page 359) 2 The Inter-Integrated Circuit (I C) bus provides bi-directional data transfer through a two-wire design (a serial data line SDA and a serial clock line SCL). 2 2 The I C bus interfaces to external I C devices such as serial memory (RAMs and ROMs), networking 2 devices, LCDs, tone generators, and so on. The I C bus may also be used for system testing and diagnostic purposes in product development and manufacture. 2 The LM3S8938 controller includes two I C modules that provide the ability to communicate to other 2 2 IC devices over an I C bus. The I C bus supports devices that can both transmit and receive (write and read) data. 2 2 Devices on the I C bus can be designated as either a master or a slave. Each I C module supports both sending and receiving data as either a master or a slave, and also supports the simultaneous 2 operation as both a master and a slave. The four I C modes are: Master Transmit, Master Receive, Slave Transmit, and Slave Receive. ® 2 A Stellaris I C module can operate at two speeds: Standard (100 Kbps) and Fast (400 Kbps). 2 2 Both the I C master and slave can generate interrupts. The I C master generates interrupts when 2 a transmit or receive operation completes (or aborts due to an error). The I C slave generates interrupts when data has been sent or requested by a master. 1.4.3.4 Controller Area Network (see page 394) Controller Area Network (CAN) is a multicast shared serial-bus standard for connecting electronic control units (ECUs). CAN was specifically designed to be robust in electromagnetically noisy environments and can utilize a differential balanced line like RS-485 or a more robust twisted-pair wire. Originally created for automotive purposes, now it is used in many embedded control applications (for example, industrial or medical). Bit rates up to 1Mb/s are possible at network lengths below 40 meters. Decreased bit rates allow longer network distances (for example, 125 Kb/s at 500m). A transmitter sends a message to all CAN nodes (broadcasting). Each node decides on the basis of the identifier received whether it should process the message. The identifier also determines the priority that the message enjoys in competition for bus access. Each CAN message can transmit from 0 to 8 bytes of user information. The LM3S8938 includes one CAN units. 1.4.3.5 Ethernet MAC (see page 438) Ethernet is a frame-based computer networking technology for local area networks (LANs). Ethernet has been standardized as IEEE 802.3. It defines a number of wiring and signaling standards for the physical layer, two means of network access at the Media Access Control (MAC)/Data Link Layer, and a common addressing format. The Stellaris® Ethernet Controller consists of a fully integrated media access controller (MAC) and network physical (PHY) interface device. The Ethernet Controller conforms to IEEE 802.3 specifications and fully supports 10BASE-T and 100BASE-TX standards. In addition, the Ethernet Controller supports automatic MDI/MDI-X cross-over correction. 1.4.4 System Peripherals 1.4.4.1 Programmable GPIOs (see page 155) General-purpose input/output (GPIO) pins offer flexibility for a variety of connections. June 14, 2007 31 Luminary Micro Confidential-Advance Product Information Architectural Overview ® The Stellaris GPIO module is composed of seven physical GPIO blocks, each corresponding to an individual GPIO port. The GPIO module is FiRM-compliant (compliant to the ARM Foundation IP for Real-Time Microcontrollers specification) and supports 3-38 programmable input/output pins. The number of GPIOs available depends on the peripherals being used (see “Signal Tables” on page 496 for the signals available to each GPIO pin). The GPIO module features programmable interrupt generation as either edge-triggered or level-sensitive on all pins, programmable control for GPIO pad configuration, and bit masking in both read and write operations through address lines. 1.4.4.2 Four Programmable Timers (see page 196) Programmable timers can be used to count or time external events that drive the Timer input pins. ® The Stellaris General-Purpose Timer Module (GPTM) contains four GPTM blocks. Each GPTM block provides two 16-bit timer/counters that can be configured to operate independently as timers or event counters, or configured to operate as one 32-bit timer or one 32-bit Real-Time Clock (RTC). Timers can also be used to trigger analog-to-digital (ADC) conversions. When configured in 32-bit mode, a timer can run as a one-shot timer, periodic timer, or Real-Time Clock (RTC). When in 16-bit mode, a timer can run as a one-shot timer or periodic timer, and can extend its precision by using an 8-bit prescaler. A 16-bit timer can also be configured for event capture or Pulse Width Modulation (PWM) generation. 1.4.4.3 Watchdog Timer (see page 229) A watchdog timer can generate nonmaskable interrupts (NMIs) or a reset when a time-out value is reached. The watchdog timer is used to regain control when a system has failed due to a software error or to the failure of an external device to respond in the expected way. ® The Stellaris Watchdog Timer module consists of a 32-bit down counter, a programmable load register, interrupt generation logic, and a locking register. The Watchdog Timer can be configured to generate an interrupt to the controller on its first time-out, and to generate a reset signal on its second time-out. Once the Watchdog Timer has been configured, the lock register can be written to prevent the timer configuration from being inadvertently altered. 1.4.5 Memory Peripherals The LM3S8938 controller offers both SRAM and Flash memory. 1.4.5.1 SRAM (see page 131) The LM3S8938 static random access memory (SRAM) controller supports 64 KB SRAM. The internal ® SRAM of the Stellaris devices is located at offset 0x0000.0000 of the device memory map. To reduce the number of time-consuming read-modify-write (RMW) operations, ARM has introduced bit-banding technology in the new Cortex-M3 processor. With a bit-band-enabled processor, certain regions in the memory map (SRAM and peripheral space) can use address aliases to access individual bits in a single, atomic operation. 1.4.5.2 Flash (see page 132) The LM3S8938 Flash controller supports 256 KB of flash memory. The flash is organized as a set of 1-KB blocks that can be individually erased. Erasing a block causes the entire contents of the block to be reset to all 1s. These blocks are paired into a set of 2-KB blocks that can be individually protected. The blocks can be marked as read-only or execute-only, providing different levels of code protection. Read-only blocks cannot be erased or programmed, protecting the contents of those blocks from being modified. Execute-only blocks cannot be erased or programmed, and can only 32 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller be read by the controller instruction fetch mechanism, protecting the contents of those blocks from being read by either the controller or by a debugger. 1.4.6 Additional Features 1.4.6.1 Memory Map (see page 41) A memory map lists the location of instructions and data in memory. The memory map for the LM3S8938 controller can be found in “Memory Map” on page 41. Register addresses are given as a hexadecimal increment, relative to the module's base address as shown in the memory map. The ARM® Cortex™-M3 Technical Reference Manual provides further information on the memory map. 1.4.6.2 JTAG TAP Controller (see page 46) The Joint Test Action Group (JTAG) port provides a standardized serial interface for controlling the Test Access Port (TAP) and associated test logic. The TAP, JTAG instruction register, and JTAG data registers can be used to test the interconnects of assembled printed circuit boards, obtain manufacturing information on the components, and observe and/or control the inputs and outputs of the controller during normal operation. The JTAG port provides a high degree of testability and chip-level access at a low cost. The JTAG port is comprised of the standard five pins: TRST, TCK, TMS, TDI, and TDO. Data is transmitted serially into the controller on TDI and out of the controller on TDO. The interpretation of this data is dependent on the current state of the TAP controller. For detailed information on the operation of the JTAG port and TAP controller, please refer to the IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture. The Luminary Micro JTAG controller works with the ARM JTAG controller built into the Cortex-M3 core. This is implemented by multiplexing the TDO outputs from both JTAG controllers. ARM JTAG instructions select the ARM TDO output while Luminary Micro JTAG instructions select the Luminary Micro TDO outputs. The multiplexer is controlled by the Luminary Micro JTAG controller, which has comprehensive programming for the ARM, Luminary Micro, and unimplemented JTAG instructions. 1.4.6.3 System Control and Clocks (see page 57) System control determines the overall operation of the device. It provides information about the device, controls the clocking of the device and individual peripherals, and handles reset detection and reporting. 1.4.6.4 Hibernation Module (see page 113) The Hibernation module provides logic to switch power off to the main processor and peripherals, and to wake on external or time-based events. The Hibernation module includes power-sequencing logic, a real-time clock with a pair of match registers, low-battery detection circuitry, and interrupt signalling to the processor. It also includes 64 32-bit words of non-volatile memory that can be used for saving state during hibernation. 1.4.7 Hardware Details Details on the pins and package can be found in the following sections: ■ “Pin Diagram” on page 495 ■ “Signal Tables” on page 496 June 14, 2007 33 Luminary Micro Confidential-Advance Product Information Architectural Overview ■ “Operating Characteristics” on page 510 ■ “Electrical Characteristics” on page 511 ■ “Package Information” on page 525 34 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 ARM Cortex-M3 Processor Core The ARM Cortex-M3 processor provides the core for a high-performance, low-cost platform that meets the needs of minimal memory implementation, reduced pin count, and low power consumption, while delivering outstanding computational performance and exceptional system response to interrupts. Features include: ■ Compact core. ■ Thumb-2 instruction set, delivering the high-performance expected of an ARM core in the memory size usually associated with 8- and 16-bit devices; typically in the range of a few kilobytes of memory for microcontroller class applications. ■ Speedy application execution through Harvard architecture characterized by separate buses for instruction and data. ■ Exceptional interrupt handling, by implementing the register manipulations required for handling an interrupt in hardware. ■ Memory protection unit (MPU) to provide a privileged mode of operation for complex applications. ■ Migration from the ARM7(TM) processor family for better performance and power efficiency. ■ Full-featured debug solution with a: – Serial Wire JTAG Debug Port (SWJ-DP) – Flash Patch and Breakpoint (FPB) unit for implementing breakpoints – Data Watchpoint and Trigger (DWT) unit for implementing watchpoints, trigger resources, and system profiling – Instrumentation Trace Macrocell (ITM) for support of printf style debugging – Trace Port Interface Unit ( TPIU) for bridging to a Trace Port Analyzer ® The Stellaris family of microcontrollers builds on this core to bring high-performance 32-bit computing to cost-sensitive embedded microcontroller applications, such as factory automation and control, industrial control power devices, building and home automation, and stepper motors. For more information on the ARM Cortex-M3 processor core, see the ARM® Cortex™-M3 Technical Reference Manual. For information on SWJ-DP, see the ARM® CoreSight Technical Reference Manual. June 14, 2007 35 Luminary Micro Confidential-Advance Product Information ARM Cortex-M3 Processor Core 2.1 Block Diagram Figure 2-1. CPU Block Diagram Nested Vectored Interrupt Controller Interrupts ARM Cortex-M3 CM3 Core Sleep Debug Instructions Data Trace Port Interface Unit Memory Protection Unit Flash Patch and Breakpoint 2.2 Adv. HighPerf. Bus Access Port Private Peripheral Bus (external) Instrumentation Data Watchpoint Trace Macrocell and Trace ROM Table Private Peripheral Bus (internal) Serial Wire JTAG Debug Port Serial Wire Output Trace Port (SWO) Adv. Peripheral Bus Bus Matrix I-code bus D-code bus System bus Functional Description Important: The ARM® Cortex™-M3 Technical Reference Manual describes all the features of an ARM Cortex-M3 in detail. However, these features differ based on the implementation. ® This section describes the Stellaris implementation. Luminary Micro has implemented the ARM Cortex-M3 core as shown in Figure 2-1 on page 36. As noted in the ARM® Cortex™-M3 Technical Reference Manual, several Cortex-M3 components are flexible in their implementation: SW/JTAG-DP, ETM, TPIU, the ROM table, the MPU, and the Nested Vectored Interrupt Controller (NVIC). Each of these is addressed in the sections that follow. 2.2.1 Serial Wire and JTAG Debug Luminary Micro has replaced the ARM SW-DP and JTAG-DP with the ARM CoreSight™-compliant Serial Wire JTAG Debug Port (SWJ-DP) interface. This means Chapter 12, “Debug Port,” of the ® ARM® Cortex™-M3 Technical Reference Manual does not apply to Stellaris devices. The SWJ-DP interface combines the SWD and JTAG debug ports into one module. See the CoreSight™ Design Kit Technical Reference Manual for details on SWJ-DP. 36 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2.2.2 Embedded Trace Macrocell (ETM) ® ETM was not implemented in the Stellaris devices. This means Chapters 15 and 16 of the ARM® Cortex™-M3 Technical Reference Manual can be ignored. 2.2.3 Trace Port Interface Unit (TPIU) The TPIU acts as a bridge between the Cortex-M3 trace data from the ITM, and an off-chip Trace ® Port Analyzer. The Stellaris devices have implemented TPIU as shown in Figure 2-2 on page 37. This is similar to the non-ETM version described in the ARM® Cortex™-M3 Technical Reference Manual, however, SWJ-DP only provides SWV output for the TPIU. Figure 2-2. TPIU Block Diagram 2.2.4 Debug ATB Slave Port ATB Interface APB Slave Port APB Interface Asynchronous FIFO Trace Out (serializer) Serial Wire Trace Port (SWO) ROM Table The default ROM table was implemented as described in the ARM® Cortex™-M3 Technical Reference Manual. 2.2.5 Memory Protection Unit (MPU) The Memory Protection Unit (MPU) is included on the LM3S8938 controller and supports the standard ARMv7 Protected Memory System Architecture (PMSA) model. The MPU provides full support for protection regions, overlapping protection regions, access permissions, and exporting memory attributes to the system. 2.2.6 Nested Vectored Interrupt Controller (NVIC) The Nested Vectored Interrupt Controller (NVIC): ■ Facilitates low-latency exception and interrupt handling June 14, 2007 37 Luminary Micro Confidential-Advance Product Information ARM Cortex-M3 Processor Core ■ Controls power management ■ Implements system control registers The NVIC supports up to 240 dynamically reprioritizable interrupts each with up to 256 levels of priority. The NVIC and the processor core interface are closely coupled, which enables low latency interrupt processing and efficient processing of late arriving interrupts. The NVIC maintains knowledge of the stacked (nested) interrupts to enable tail-chaining of interrupts. You can only fully access the NVIC from privileged mode, but you can pend interrupts in user-mode if you enable the Configuration Control Register (see the ARM® Cortex™-M3 Technical Reference Manual). Any other user-mode access causes a bus fault. All NVIC registers are accessible using byte, halfword, and word unless otherwise stated. All NVIC registers and system debug registers are little endian regardless of the endianness state of the processor. 2.2.6.1 Interrupts The ARM® Cortex™-M3 Technical Reference Manual describes the maximum number of interrupts and interrupt priorities. The LM3S8938 microcontroller supports 34 interrupts with eight priority levels. 2.2.6.2 System Timer (SysTick) Cortex-M3 includes an integrated system timer, SysTick. SysTick provides a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter can be used in several different ways, for example: ■ An RTOS tick timer which fires at a programmable rate (for example 100 Hz) and invokes a SysTick routine. ■ A high-speed alarm timer using the system clock. ■ A variable rate alarm or signal timer—the duration is range-dependent on the reference clock used and the dynamic range of the counter. ■ A simple counter. Software can use this to measure time to completion and time used. ■ An internal clock source control based on missing/meeting durations. The COUNTFLAG bit-field in the control and status register can be used to determine if an action completed within a set duration, as part of a dynamic clock management control loop. Functional Description The timer consists of three registers: ■ A control and status counter to configure its clock, enable the counter, enable the SysTick interrupt, and determine counter status. ■ The reload value for the counter, used to provide the counter's wrap value. ■ The current value of the counter. A fourth register, the SysTick Calibration Value Register, is not implemented in the Stellaris devices. 38 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller When enabled, the timer counts down from the reload value to zero, reloads (wraps) to the value in the SysTick Reload Value register on the next clock edge, then decrements on subsequent clocks. Writing a value of zero to the Reload Value register disables the counter on the next wrap. When the counter reaches zero, the COUNTFLAG status bit is set. The COUNTFLAG bit clears on reads. Writing to the Current Value register clears the register and the COUNTFLAG status bit. The write does not trigger the SysTick exception logic. On a read, the current value is the value of the register at the time the register is accessed. If the core is in debug state (halted), the counter will not decrement. The timer is clocked with respect to a reference clock. The reference clock can be the core clock or an external clock source. SysTick Control and Status Register Use the SysTick Control and Status Register to enable the SysTick features. The reset is 0x0000.0000. Bit/Field Name 31:17 reserved 16 15:3 2 Type Reset Description RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. COUNTFLAG R/W 0 Returns 1 if timer counted to 0 since last time this was read. Clears on read by application. If read by the debugger using the DAP, this bit is cleared on read-only if the MasterType bit in the AHB-AP Control Register is set to 0. Otherwise, the COUNTFLAG bit is not changed by the debugger read. R/W 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. CLKSOURCE R/W 0 0 = external reference clock. (Not implemented for Stellaris microcontrollers.) reserved 1 = core clock. If no reference clock is provided, it is held at 1 and so gives the same time as the core clock. The core clock must be at least 2.5 times faster than the reference clock. If it is not, the count values are Unpredictable. 1 TICKINT R/W 0 1 = counting down to 0 pends the SysTick handler. 0 = counting down to 0 does not pend the SysTick handler. Software can use the COUNTFLAG to determine if ever counted to 0. 0 ENABLE R/W 0 1 = counter operates in a multi-shot way. That is, counter loads with the Reload value and then begins counting down. On reaching 0, it sets the COUNTFLAG to 1 and optionally pends the SysTick handler, based on TICKINT. It then loads the Reload value again, and begins counting. 0 = counter disabled. SysTick Reload Value Register Use the SysTick Reload Value Register to specify the start value to load into the current value register when the counter reaches 0. It can be any value between 1 and 0x00FFFFFF. A start value of 0 is possible, but has no effect because the SysTick interrupt and COUNTFLAG are activated when counting from 1 to 0. Therefore, as a multi-shot timer, repeated over and over, it fires every N+1 clock pulse, where N is any value from 1 to 0x00FFFFFF. So, if the tick interrupt is required every 100 clock pulses, 99 must be written into the RELOAD. If a new value is written on each tick interrupt, so treated as single shot, then the actual count down must be written. For example, if a tick is next required after 400 clock pulses, 400 must be written into the RELOAD. June 14, 2007 39 Luminary Micro Confidential-Advance Product Information ARM Cortex-M3 Processor Core Bit/Field Name 31:24 reserved Type Reset Description 23:0 RELOAD W1C RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. - Value to load into the SysTick Current Value Register when the counter reaches 0. SysTick Current Value Register Use the SysTick Current Value Register to find the current value in the register. Bit/Field Name 31:24 reserved 23:0 Type Reset Description RO CURRENT W1C 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. - Current value at the time the register is accessed. No read-modify-write protection is provided, so change with care. This register is write-clear. Writing to it with any value clears the register to 0. Clearing this register also clears the COUNTFLAG bit of the SysTick Control and Status Register. SysTick Calibration Value Register The SysTick Calibration Value register is not implemented. 40 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 3 Memory Map The memory map for the LM3S8938 controller is provided in Table 3-1 on page 41. In this manual, register addresses are given as a hexadecimal increment, relative to the module’s base address as shown in the memory map. See also Chapter 4, “Memory Map” in the ARM® Cortex™-M3 Technical Reference Manual. Note: In Table 3-1 on page 41 addresses not listed are reserved. a Table 3-1. Memory Map Start End Description 0x1FFF.FFFF On-chip flash For details on registers, see page ... Memory 0x0000.0000 b 135 c 0x2000.0000 0x200F.FFFF Bit-banded on-chip SRAM 135 0x2010.0000 0x21FF.FFFF Reserved non-bit-banded SRAM space - 0x2200.0000 0x23FF.FFFF Bit-band alias of 0x2000.0000 through 0x200F.FFFF 131 0x2400.0000 0x3FFF.FFFF Reserved non-bit-banded SRAM space - 0x4000.0000 0x4000.0FFF Watchdog timer 231 0x4000.1000 0x4000.3FFF Reserved - 0x4000.4000 0x4000.4FFF GPIO Port A 161 0x4000.5000 0x4000.5FFF GPIO Port B 161 0x4000.6000 0x4000.6FFF GPIO Port C 161 0x4000.7000 0x4000.7FFF GPIO Port D 161 0x4000.8000 0x4000.8FFF SSI0 336 0x4000.A000 0x4000.BFFF Reserved - 0x4000.C000 0x4000.CFFF UART0 292 0x4000.D000 0x4000.DFFF UART1 292 0x4000.E000 0x4000.EFFF UART2 292 0x4000.F000 0x4000.FFFF Reserved - 0x4001.0000 0x4001.FFFF Reserved for future FiRM peripherals - 0x4002.0000 0x4002.07FF I2C Master 0 372 0x4002.0800 0x4002.0FFF I2C Slave 0 385 0x4002.1000 0x4002.17FF I2C Master 1 372 0x4001.1800 0x4002.1FFF I2C Slave 1 385 0x4002.2000 0x4002.3FFF Reserved - 0x4002.4000 0x4002.4FFF GPIO Port E 161 0x4002.5000 0x4002.5FFF GPIO Port F 161 0x4002.6000 0x4002.6FFF GPIO Port G 161 0x4002.9000 0x4002.BFFF Reserved - 0x4002.E000 0x4002.FFFF Reserved - FiRM Peripherals Peripherals June 14, 2007 41 Luminary Micro Confidential-Advance Product Information Memory Map Start End Description For details on registers, see page ... 0x4003.0000 0x4003.0FFF Timer0 207 0x4003.1000 0x4003.1FFF Timer1 207 0x4003.2000 0x4003.2FFF Timer2 207 0x4003.3000 0x4003.3FFF Timer3 207 0x4003.4000 0x4003.7FFF Reserved - 0x4003.8000 0x4003.8FFF ADC 258 0x4003.9000 0x4003.BFFF Reserved - 0x4003.C000 0x4003.CFFF Analog Comparators 482 0x4003.D000 0x4003.FFFF Reserved - 0x4004.0000 0x4004.0FFF CAN0 Controller 407 0x4004.3000 0x4004.7FFF Reserved - 0x4004.8000 0x4004.8FFF Ethernet Controller 446 0x4004.9000 0x4004.BFFF Reserved - 0x4004.C000 0x400F.BFFF Reserved - 0x400F.C000 0x400F.CFFF Hibernation Module 118 0x400F.D000 0x400F.DFFF Flash control 135 0x400F.E000 0x400F.EFFF System control 64 0x400F.F000 0x400F.FFFF Reserved - 0x4011.1000 0x4011.1FFF Reserved - 0x4012.0000 0x41FF.FFFF Reserved for non bit-banded peripheral space - 0x4200.0000 0x43FF.FFFF Bit-banded alias of 0x4000.0000 through 0x400F.FFFF - 0x4400.0000 0x5E32.FFFF Reserved for non bit-banded peripheral space - 0x5E34.0000 0x5FFF.FFFF Reserved - 0x6000.0000 0xDFFF.FFFF Reserved for external devices - 0xE000.0000 0xE000.0FFF Instrumentation Trace Macrocell (ITM) 0xE000.1000 0xE000.1FFF Data Watchpoint and Trace (DWT) 0xE000.2000 0xE000.2FFF Flash Patch and Breakpoint (FPB) 0xE000.3000 0xE000.DFFF Reserved ARM® Cortex™-M3 Technical Reference Manual 0xE000.E000 0xE000.EFFF Nested Vectored Interrupt Controller (NVIC) 0xE000.F000 0xE003.FFFF Reserved 0xE004.0000 0xE004.0FFF Trace Port Interface Unit (TPIU) 0xE004.1000 0xE004.1FFF Reserved - 0xE004.2000 0xE00F.FFFF Reserved - 0xE010.0000 0xFFFF.FFFF Reserved for vendor peripherals - Private Peripheral Bus a. All reserved space returns a bus fault when read or written. b. The unavailable flash will bus fault throughout this range. c. The unavailable SRAM will bus fault throughout this range. 42 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 4 Interrupts The ARM Cortex-M3 processor and the Nested Vectored Interrupt Controller (NVIC) prioritize and handle all exceptions. All exceptions are handled in Handler Mode. The processor state is automatically stored to the stack on an exception, and automatically restored from the stack at the end of the Interrupt Service Routine (ISR). The vector is fetched in parallel to the state saving, which enables efficient interrupt entry. The processor supports tail-chaining, which enables back-to-back interrupts to be performed without the overhead of state saving and restoration. Table 4-1 on page 43 lists all the exceptions. Software can set eight priority levels on seven of these exceptions (system handlers) as well as on 34 interrupts (listed in Table 4-2 on page 44). Priorities on the system handlers are set with the NVIC System Handler Priority registers. Interrupts are enabled through the NVIC Interrupt Set Enable register and prioritized with the NVIC Interrupt Priority registers. You can also group priorities by splitting priority levels into pre-emption priorities and subpriorities. All the interrupt registers are described in Chapter 8, “Nested Vectored Interrupt Controller” in the ARM® Cortex™-M3 Technical Reference Manual. Internally, the highest user-settable priority (0) is treated as fourth priority, after a Reset, NMI, and a Hard Fault. Note that 0 is the default priority for all the settable priorities. If you assign the same priority level to two or more interrupts, their hardware priority (the lower the position number) determines the order in which the processor activates them. For example, if both GPIO Port A and GPIO Port B are priority level 1, then GPIO Port A has higher priority. See Chapter 5, “Exceptions” and Chapter 8, “Nested Vectored Interrupt Controller” in the ARM® Cortex™-M3 Technical Reference Manual for more information on exceptions and interrupts. Note: In Table 4-2 on page 44 interrupts not listed are reserved. Table 4-1. Exception Types Exception Type Position - 0 Reset 1 Non-Maskable Interrupt (NMI) 2 a Priority - Description Stack top is loaded from first entry of vector table on reset. -3 (highest) Invoked on power up and warm reset. On first instruction, drops to lowest priority (and then is called the base level of activation). This is asynchronous. -2 Cannot be stopped or preempted by any exception but reset. This is asynchronous. An NMI is only producible by software, using the NVIC Interrupt Control State register. Hard Fault 3 -1 Memory Management 4 settable Bus Fault 5 settable All classes of Fault, when the fault cannot activate due to priority or the configurable fault handler has been disabled. This is synchronous. MPU mismatch, including access violation and no match. This is synchronous. The priority of this exception can be changed. Pre-fetch fault, memory access fault, and other address/memory related faults. This is synchronous when precise and asynchronous when imprecise. You can enable or disable this fault. Usage Fault SVCall 6 settable 7-10 - 11 settable Usage fault, such as undefined instruction executed or illegal state transition attempt. This is synchronous. Reserved. System service call with SVC instruction. This is synchronous. June 14, 2007 43 Luminary Micro Confidential-Advance Product Information Interrupts Exception Type Position a Priority Description Debug Monitor 12 settable - 13 - PendSV 14 settable Pendable request for system service. This is asynchronous and only pended by software. 15 settable System tick timer has fired. This is asynchronous. 16 and above settable Asserted from outside the ARM Cortex-M3 core and fed through the NVIC (prioritized). These are all asynchronous. Table 4-2 on page 44 lists the interrupts on the LM3S8938 controller. SysTick Interrupts Debug monitor (when not halting). This is synchronous, but only active when enabled. It does not activate if lower priority than the current activation. Reserved. a. 0 is the default priority for all the settable priorities. Table 4-2. Interrupts Interrupt (Bit in Interrupt Registers) Description 0 GPIO Port A 1 GPIO Port B 2 GPIO Port C 3 GPIO Port D 4 GPIO Port E 5 UART0 6 UART1 7 SSI0 8 I2C0 14 ADC Sequence 0 15 ADC Sequence 1 16 ADC Sequence 2 17 ADC Sequence 3 18 Watchdog timer 19 Timer0 A 20 Timer0 B 21 Timer1 A 22 Timer1 B 23 Timer2 A 24 Timer2 B 25 Analog Comparator 0 26 Analog Comparator 1 27 Analog Comparator 2 28 System Control 29 Flash Control 30 GPIO Port F 31 GPIO Port G 33 UART2 35 Timer3 A 36 Timer3 B 44 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Interrupt (Bit in Interrupt Registers) Description 37 I2C1 39 CAN0 42 Ethernet Controller 43 Hibernation Module 44-47 Reserved June 14, 2007 45 Luminary Micro Confidential-Advance Product Information JTAG Interface 5 JTAG Interface The Joint Test Action Group (JTAG) port is an IEEE standard that defines a Test Access Port and Boundary Scan Architecture for digital integrated circuits and provides a standardized serial interface for controlling the associated test logic. The TAP, Instruction Register (IR), and Data Registers (DR) can be used to test the interconnections of assembled printed circuit boards and obtain manufacturing information on the components. The JTAG Port also provides a means of accessing and controlling design-for-test features such as I/O pin observation and control, scan testing, and debugging. The JTAG port is comprised of the standard five pins: TRST, TCK, TMS, TDI, and TDO. Data is transmitted serially into the controller on TDI and out of the controller on TDO. The interpretation of this data is dependent on the current state of the TAP controller. For detailed information on the operation of the JTAG port and TAP controller, please refer to the IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture. The Luminary Micro JTAG controller works with the ARM JTAG controller built into the Cortex-M3 core. This is implemented by multiplexing the TDO outputs from both JTAG controllers. ARM JTAG instructions select the ARM TDO output while Luminary Micro JTAG instructions select the Luminary Micro TDO outputs. The multiplexer is controlled by the Luminary Micro JTAG controller, which has comprehensive programming for the ARM, LMI, and unimplemented JTAG instructions. The JTAG module has the following features: ■ IEEE 1149.1-1990 compatible Test Access Port (TAP) controller ■ Four-bit Instruction Register (IR) chain for storing JTAG instructions ■ IEEE standard instructions: – BYPASS instruction – IDCODE instruction – SAMPLE/PRELOAD instruction – EXTEST instruction – INTEST instruction ■ ARM additional instructions: – APACC instruction – DPACC instruction – ABORT instruction ■ Integrated ARM Serial Wire Debug (SWD) See the ARM® Cortex™-M3 Technical Reference Manual for more information on the ARM JTAG controller. 46 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 5.1 Block Diagram Figure 5-1. JTAG Module Block Diagram TRST TCK TMS TDI TAP Controller Instruction Register (IR) BYPASS Data Register TDO Boundary Scan Data Register IDCODE Data Register ABORT Data Register DPACC Data Register APACC Data Register Cortex-M3 Debug Port 5.2 Functional Description A high-level conceptual drawing of the JTAG module is shown in Figure 5-1 on page 47. The JTAG module is composed of the Test Access Port (TAP) controller and serial shift chains with parallel update registers. The TAP controller is a simple state machine controlled by the TRST, TCK and TMS inputs. The current state of the TAP controller depends on the current value of TRST and the sequence of values captured on TMS at the rising edge of TCK. The TAP controller determines when the serial shift chains capture new data, shift data from TDI towards TDO, and update the parallel load registers. The current state of the TAP controller also determines whether the Instruction Register (IR) chain or one of the Data Register (DR) chains is being accessed. The serial shift chains with parallel load registers are comprised of a single Instruction Register (IR) chain and multiple Data Register (DR) chains. The current instruction loaded in the parallel load register determines which DR chain is captured, shifted, or updated during the sequencing of the TAP controller. Some instructions, like EXTEST and INTEST, operate on data currently in a DR chain and do not capture, shift, or update any of the chains. Instructions that are not implemented decode to the BYPASS instruction to ensure that the serial path between TDI and TDO is always connected (see Table 5-2 on page 53 for a list of implemented instructions). See “JTAG and Boundary Scan” on page 521 for JTAG timing diagrams. June 14, 2007 47 Luminary Micro Confidential-Advance Product Information JTAG Interface 5.2.1 JTAG Interface Pins The JTAG interface consists of five standard pins: TRST, TCK, TMS, TDI, and TDO. These pins and their associated reset state are given in Table 5-1 on page 48. Detailed information on each pin follows. Table 5-1. JTAG Port Pins Reset State Pin Name Data Direction Internal Pull-Up Internal Pull-Down Drive Strength Drive Value 5.2.1.1 TRST Input Enabled Disabled N/A N/A TCK Input Enabled Disabled N/A N/A TMS Input Enabled Disabled N/A N/A TDI Input Enabled Disabled N/A N/A TDO Output Enabled Disabled 2-mA driver High-Z Test Reset Input (TRST) The TRST pin is an asynchronous active Low input signal for initializing and resetting the JTAG TAP controller and associated JTAG circuitry. When TRST is asserted, the TAP controller resets to the Test-Logic-Reset state and remains there while TRST is asserted. When the TAP controller enters the Test-Logic-Reset state, the JTAG Instruction Register (IR) resets to the default instruction, IDCODE. By default, the internal pull-up resistor on the TRST pin is enabled after reset. Changes to the pull-up resistor settings on GPIO Port B should ensure that the internal pull-up resistor remains enabled on PB7/TRST; otherwise JTAG communication could be lost. 5.2.1.2 Test Clock Input (TCK) The TCK pin is the clock for the JTAG module. This clock is provided so the test logic can operate independently of any other system clocks. In addition, it ensures that multiple JTAG TAP controllers that are daisy-chained together can synchronously communicate serial test data between components. During normal operation, TCK is driven by a free-running clock with a nominal 50% duty cycle. When necessary, TCK can be stopped at 0 or 1 for extended periods of time. While TCK is stopped at 0 or 1, the state of the TAP controller does not change and data in the JTAG Instruction and Data Registers is not lost. By default, the internal pull-up resistor on the TCK pin is enabled after reset. This assures that no clocking occurs if the pin is not driven from an external source. The internal pull-up and pull-down resistors can be turned off to save internal power as long as the TCK pin is constantly being driven by an external source. 5.2.1.3 Test Mode Select (TMS) The TMS pin selects the next state of the JTAG TAP controller. TMS is sampled on the rising edge of TCK. Depending on the current TAP state and the sampled value of TMS, the next state is entered. Because the TMS pin is sampled on the rising edge of TCK, the IEEE Standard 1149.1 expects the value on TMS to change on the falling edge of TCK. Holding TMS high for five consecutive TCK cycles drives the TAP controller state machine to the Test-Logic-Reset state. When the TAP controller enters the Test-Logic-Reset state, the JTAG Instruction Register (IR) resets to the default instruction, IDCODE. Therefore, this sequence can be used as a reset mechanism, similar to asserting TRST. The JTAG Test Access Port state machine can be seen in its entirety in Figure 5-2 on page 50. 48 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller By default, the internal pull-up resistor on the TMS pin is enabled after reset. Changes to the pull-up resistor settings on GPIO Port C should ensure that the internal pull-up resistor remains enabled on PC1/TMS; otherwise JTAG communication could be lost. 5.2.1.4 Test Data Input (TDI) The TDI pin provides a stream of serial information to the IR chain and the DR chains. TDI is sampled on the rising edge of TCK and, depending on the current TAP state and the current instruction, presents this data to the proper shift register chain. Because the TDI pin is sampled on the rising edge of TCK, the IEEE Standard 1149.1 expects the value on TDI to change on the falling edge of TCK. By default, the internal pull-up resistor on the TDI pin is enabled after reset. Changes to the pull-up resistor settings on GPIO Port C should ensure that the internal pull-up resistor remains enabled on PC2/TDI; otherwise JTAG communication could be lost. 5.2.1.5 Test Data Output (TDO) The TDO pin provides an output stream of serial information from the IR chain or the DR chains. The value of TDO depends on the current TAP state, the current instruction, and the data in the chain being accessed. In order to save power when the JTAG port is not being used, the TDO pin is placed in an inactive drive state when not actively shifting out data. Because TDO can be connected to the TDI of another controller in a daisy-chain configuration, the IEEE Standard 1149.1 expects the value on TDO to change on the falling edge of TCK. By default, the internal pull-up resistor on the TDO pin is enabled after reset. This assures that the pin remains at a constant logic level when the JTAG port is not being used. The internal pull-up and pull-down resistors can be turned off to save internal power if a High-Z output value is acceptable during certain TAP controller states. 5.2.2 JTAG TAP Controller The JTAG TAP controller state machine is shown in Figure 5-2 on page 50. The TAP controller state machine is reset to the Test-Logic-Reset state on the assertion of a Power-On-Reset (POR) or the assertion of TRST. Asserting the correct sequence on the TMS pin allows the JTAG module to shift in new instructions, shift in data, or idle during extended testing sequences. For detailed information on the function of the TAP controller and the operations that occur in each state, please refer to IEEE Standard 1149.1. June 14, 2007 49 Luminary Micro Confidential-Advance Product Information JTAG Interface Figure 5-2. Test Access Port State Machine Test Logic Reset 1 0 Run Test Idle 0 Select DR Scan 1 Select IR Scan 1 0 1 0 Capture DR 1 Capture IR 0 0 Shift DR Shift IR 0 1 Exit 1 DR Exit 1 IR 1 Pause IR 0 1 Exit 2 DR 0 1 0 Exit 2 IR 1 1 Update DR 5.2.3 1 0 Pause DR 1 0 1 0 0 1 0 Update IR 1 0 Shift Registers The Shift Registers consist of a serial shift register chain and a parallel load register. The serial shift register chain samples specific information during the TAP controller’s CAPTURE states and allows this information to be shifted out of TDO during the TAP controller’s SHIFT states. While the sampled data is being shifted out of the chain on TDO, new data is being shifted into the serial shift register on TDI. This new data is stored in the parallel load register during the TAP controller’s UPDATE states. Each of the shift registers is discussed in detail in “Register Descriptions” on page 53. 5.2.4 Operational Considerations There are certain operational considerations when using the JTAG module. Because the JTAG pins can be programmed to be GPIOs, board configuration and reset conditions on these pins must be considered. In addition, because the JTAG module has integrated ARM Serial Wire Debug, the method for switching between these two operational modes is described below. 50 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 5.2.4.1 GPIO Functionality When the controller is reset with either a POR or RST, the JTAG/SWD port pins default to their JTAG/SWD configurations. The default configuration includes enabling digital functionality (setting GPIODEN to 1), enabling the pull-up resistors (setting GPIOPUR to 1), and enabling the alternate hardware function (setting GPIOAFSEL to 1) for the PB7 and PC[3:0] JTAG/SWD pins. It is possible for software to configure these pins as GPIOs after reset by writing 0s to PB7 and PC[3:0] in the GPIOAFSEL register. If the user does not require the JTAG/SWD port for debugging or board-level testing, this provides five more GPIOs for use in the design. Caution – If the JTAG pins are used as GPIOs in a design, PB7 and PC2 cannot have external pull-down resistors connected to both of them at the same time. If both pins are pulled Low during reset, the controller has unpredictable behavior. If this happens, remove one or both of the pull-down resistors, and apply RST or power-cycle the part. In addition, it is possible to create a software sequence that prevents the debugger from connecting to the Stellaris® microcontroller. If the program code loaded into flash immediately changes the JTAG pins to their GPIO functionality, the debugger may not have enough time to connect and halt the controller before the JTAG pin functionality switches. This may lock the debugger out of the part. This can be avoided with a software routine that restores JTAG functionality based on an external or software trigger. The commit control registers provide a layer of protection against accidental programming of critical hardware peripherals. Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL) register (see page 171) are not committed to storage unless the GPIO Lock (GPIOLOCK) register (see page 181) has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register (see page 182) have been set to 1. Recovering a "Locked" Device If software configures any of the JTAG/SWD pins as GPIO and loses the ability to communicate with the debugger, there is a debug sequence that can be used to recover the device. Performing a total of ten JTAG-to-SWD and SWD-to-JTAG switch sequences while holding the device in reset mass erases the flash memory. The sequence to recover the device is: 1. Assert and hold the RST signal. 2. Perform the JTAG-to-SWD switch sequence. 3. Perform the SWD-to-JTAG switch sequence. 4. Perform the JTAG-to-SWD switch sequence. 5. Perform the SWD-to-JTAG switch sequence. 6. Perform the JTAG-to-SWD switch sequence. 7. Perform the SWD-to-JTAG switch sequence. 8. Perform the JTAG-to-SWD switch sequence. 9. Perform the SWD-to-JTAG switch sequence. 10. Perform the JTAG-to-SWD switch sequence. 11. Perform the SWD-to-JTAG switch sequence. June 14, 2007 51 Luminary Micro Confidential-Advance Product Information JTAG Interface 12. Release the RST signal. The JTAG-to-SWD and SWD-to-JTAG switch sequences are described in “ARM Serial Wire Debug (SWD)” on page 52. When performing switch sequences for the purpose of recovering the debug capabilities of the device, only steps 1 and 2 of the switch sequence need to be performed. 5.2.4.2 ARM Serial Wire Debug (SWD) In order to seamlessly integrate the ARM Serial Wire Debug (SWD) functionality, a serial-wire debugger must be able to connect to the Cortex-M3 core without having to perform, or have any knowledge of, JTAG cycles. This is accomplished with a SWD preamble that is issued before the SWD session begins. The preamble used to enable the SWD interface of the SWJ-DP module starts with the TAP controller in the Test-Logic-Reset state. From here, the preamble sequences the TAP controller through the following states: Run Test Idle, Select DR, Select IR, Test Logic Reset, Test Logic Reset, Run Test Idle, Run Test Idle, Select DR, Select IR, Test Logic Reset, Test Logic Reset, Run Test Idle, Run Test Idle, Select DR, Select IR, and Test Logic Reset states. Stepping through this sequences of the TAP state machine enables the SWD interface and disables the JTAG interface. For more information on this operation and the SWD interface, see the ARM® Cortex™-M3 Technical Reference Manual and the ARM® CoreSight Technical Reference Manual. Because this sequence is a valid series of JTAG operations that could be issued, the ARM JTAG TAP controller is not fully compliant to the IEEE Standard 1149.1. This is the only instance where the ARM JTAG TAP controller does not meet full compliance with the specification. Due to the low probability of this sequence occurring during normal operation of the TAP controller, it should not affect normal performance of the JTAG interface. JTAG-to-SWD Switching To switch the operating mode of the Debug Access Port (DAP) from JTAG to SWD mode, the external debug hardware must send a switch sequence to the device. The 16-bit switch sequence for switching to SWD mode is defined as b1110011110011110, transmitted LSB first. This can also be represented as 16'hE79E when transmitted LSB first. The complete switch sequence should consist of the following transactions on the TCK/SWCLK and TMS/SWDIO signals: 1. Send at least 50 TCK/SWCLK cycles with TMS/SWDIO set to 1. This ensures that both JTAG and SWD are in their reset/idle states. 2. Send the 16-bit JTAG-to-SWD switch sequence, 16'hE79E. 3. Send at least 50 TCK/SWCLK cycles with TMS/SWDIO set to 1. This ensures that if SWJ-DP was already in SWD mode, before sending the switch sequence, the SWD goes into the line reset state. SWD-to-JTAG Switching To switch the operating mode of the Debug Access Port (DAP) from SWD to JTAG mode, the external debug hardware must send a switch sequence to the device. The 16-bit switch sequence for switching to JTAG mode is defined as b1110011110011110, transmitted LSB first. This can also be represented as 16'hE73C when transmitted LSB first. The complete switch sequence should consist of the following transactions on the TCK/SWCLK and TMS/SWDIO signals: 1. Send at least 50 TCK/SWCLK cycles with TMS/SWDIO set to 1. This ensures that both JTAG and SWD are in their reset/idle states. 52 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2. Send the 16-bit SWD-to-JTAG switch sequence, 16'hE73C. 3. Send at least 5 TCK/SWCLK cycles with TMS/SWDIO set to 1. This ensures that if SWJ-DP was already in JTAG mode, before sending the switch sequence, the JTAG goes into the Test Logic Reset state. 5.3 Initialization and Configuration After a Power-On-Reset or an external reset (RST), the JTAG pins are automatically configured for JTAG communication. No user-defined initialization or configuration is needed. However, if the user application changes these pins to their GPIO function, they must be configured back to their JTAG functionality before JTAG communication can be restored. This is done by enabling the five JTAG pins (PB7 and PC[3:0]) for their alternate function using the GPIOAFSEL register. 5.4 Register Descriptions There are no APB-accessible registers in the JTAG TAP Controller or Shift Register chains. The registers within the JTAG controller are all accessed serially through the TAP Controller. The registers can be broken down into two main categories: Instruction Registers and Data Registers. 5.4.1 Instruction Register (IR) The JTAG TAP Instruction Register (IR) is a four-bit serial scan chain with a parallel load register connected between the JTAG TDI and TDO pins. When the TAP Controller is placed in the correct states, bits can be shifted into the Instruction Register. Once these bits have been shifted into the chain and updated, they are interpreted as the current instruction. The decode of the Instruction Register bits is shown in Table 5-2 on page 53. A detailed explanation of each instruction, along with its associated Data Register, follows. Table 5-2. JTAG Instruction Register Commands IR[3:0] Instruction 0000 EXTEST Drives the values preloaded into the Boundary Scan Chain by the SAMPLE/PRELOAD instruction onto the pads. 0001 INTEST Drives the values preloaded into the Boundary Scan Chain by the SAMPLE/PRELOAD instruction into the controller. 0010 5.4.1.1 Description SAMPLE / PRELOAD Captures the current I/O values and shifts the sampled values out of the Boundary Scan Chain while new preload data is shifted in. 1000 ABORT Shifts data into the ARM Debug Port Abort Register. 1010 DPACC Shifts data into and out of the ARM DP Access Register. 1011 APACC Shifts data into and out of the ARM AC Access Register. 1110 IDCODE Loads manufacturing information defined by the IEEE Standard 1149.1 into the IDCODE chain and shifts it out. 1111 BYPASS Connects TDI to TDO through a single Shift Register chain. All Others Reserved Defaults to the BYPASS instruction to ensure that TDI is always connected to TDO. EXTEST Instruction The EXTEST instruction does not have an associated Data Register chain. The EXTEST instruction uses the data that has been preloaded into the Boundary Scan Data Register using the SAMPLE/PRELOAD instruction. When the EXTEST instruction is present in the Instruction Register, the preloaded data in the Boundary Scan Data Register associated with the outputs and output enables are used to drive the GPIO pads rather than the signals coming from the core. This allows June 14, 2007 53 Luminary Micro Confidential-Advance Product Information JTAG Interface tests to be developed that drive known values out of the controller, which can be used to verify connectivity. 5.4.1.2 INTEST Instruction The INTEST instruction does not have an associated Data Register chain. The INTEST instruction uses the data that has been preloaded into the Boundary Scan Data Register using the SAMPLE/PRELOAD instruction. When the INTEST instruction is present in the Instruction Register, the preloaded data in the Boundary Scan Data Register associated with the inputs are used to drive the signals going into the core rather than the signals coming from the GPIO pads. This allows tests to be developed that drive known values into the controller, which can be used for testing. It is important to note that although the RST input pin is on the Boundary Scan Data Register chain, it is only observable. 5.4.1.3 SAMPLE/PRELOAD Instruction The SAMPLE/PRELOAD instruction connects the Boundary Scan Data Register chain between TDI and TDO. This instruction samples the current state of the pad pins for observation and preloads new test data. Each GPIO pad has an associated input, output, and output enable signal. When the TAP controller enters the Capture DR state during this instruction, the input, output, and output-enable signals to each of the GPIO pads are captured. These samples are serially shifted out of TDO while the TAP controller is in the Shift DR state and can be used for observation or comparison in various tests. While these samples of the inputs, outputs, and output enables are being shifted out of the Boundary Scan Data Register, new data is being shifted into the Boundary Scan Data Register from TDI. Once the new data has been shifted into the Boundary Scan Data Register, the data is saved in the parallel load registers when the TAP controller enters the Update DR state. This update of the parallel load register preloads data into the Boundary Scan Data Register that is associated with each input, output, and output enable. This preloaded data can be used with the EXTEST and INTEST instructions to drive data into or out of the controller. Please see “Boundary Scan Data Register” on page 56 for more information. 5.4.1.4 ABORT Instruction The ABORT instruction connects the associated ABORT Data Register chain between TDI and TDO. This instruction provides read and write access to the ABORT Register of the ARM Debug Access Port (DAP). Shifting the proper data into this Data Register clears various error bits or initiates a DAP abort of a previous request. Please see the “ABORT Data Register” on page 56 for more information. 5.4.1.5 DPACC Instruction The DPACC instruction connects the associated DPACC Data Register chain between TDI and TDO. This instruction provides read and write access to the DPACC Register of the ARM Debug Access Port (DAP). Shifting the proper data into this register and reading the data output from this register allows read and write access to the ARM debug and status registers. Please see “DPACC Data Register” on page 56 for more information. 5.4.1.6 APACC Instruction The APACC instruction connects the associated APACC Data Register chain between TDI and TDO. This instruction provides read and write access to the APACC Register of the ARM Debug Access Port (DAP). Shifting the proper data into this register and reading the data output from this register allows read and write access to internal components and buses through the Debug Port. Please see “APACC Data Register” on page 56 for more information. 54 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 5.4.1.7 IDCODE Instruction The IDCODE instruction connects the associated IDCODE Data Register chain between TDI and TDO. This instruction provides information on the manufacturer, part number, and version of the ARM core. This information can be used by testing equipment and debuggers to automatically configure their input and output data streams. IDCODE is the default instruction that is loaded into the JTAG Instruction Register when a power-on-reset (POR) is asserted, TRST is asserted, or the Test-Logic-Reset state is entered. Please see “IDCODE Data Register” on page 55 for more information. 5.4.1.8 BYPASS Instruction The BYPASS instruction connects the associated BYPASS Data Register chain between TDI and TDO. This instruction is used to create a minimum length serial path between the TDI and TDO ports. The BYPASS Data Register is a single-bit shift register. This instruction improves test efficiency by allowing components that are not needed for a specific test to be bypassed in the JTAG scan chain by loading them with the BYPASS instruction. Please see “BYPASS Data Register” on page 55 for more information. 5.4.2 Data Registers The JTAG module contains six Data Registers. These include: IDCODE, BYPASS, Boundary Scan, APACC, DPACC, and ABORT serial Data Register chains. Each of these Data Registers is discussed in the following sections. 5.4.2.1 IDCODE Data Register The format for the 32-bit IDCODE Data Register defined by the IEEE Standard 1149.1 is shown in Figure 5-3 on page 55. The standard requires that every JTAG-compliant device implement either the IDCODE instruction or the BYPASS instruction as the default instruction. The LSB of the IDCODE Data Register is defined to be a 1 to distinguish it from the BYPASS instruction, which has an LSB of 0. This allows auto configuration test tools to determine which instruction is the default instruction. The major uses of the JTAG port are for manufacturer testing of component assembly, and program development and debug. To facilitate the use of auto-configuration debug tools, the IDCODE instruction outputs a value of 0x3BA00477. This value indicates an ARM Cortex-M3, Version 1 processor. This allows the debuggers to automatically configure themselves to work correctly with the Cortex-M3 during debug. Figure 5-3. IDCODE Register Format 5.4.2.2 BYPASS Data Register The format for the 1-bit BYPASS Data Register defined by the IEEE Standard 1149.1 is shown in Figure 5-4 on page 56. The standard requires that every JTAG-compliant device implement either the BYPASS instruction or the IDCODE instruction as the default instruction. The LSB of the BYPASS Data Register is defined to be a 0 to distinguish it from the IDCODE instruction, which has an LSB of 1. This allows auto configuration test tools to determine which instruction is the default instruction. June 14, 2007 55 Luminary Micro Confidential-Advance Product Information JTAG Interface Figure 5-4. BYPASS Register Format 5.4.2.3 Boundary Scan Data Register The format of the Boundary Scan Data Register is shown in Figure 5-5 on page 56. Each GPIO pin, in a counter-clockwise direction from the JTAG port pins, is included in the Boundary Scan Data Register. Each GPIO pin has three associated digital signals that are included in the chain. These signals are input, output, and output enable, and are arranged in that order as can be seen in the figure. In addition to the GPIO pins, the controller reset pin, RST, is included in the chain. Because the reset pin is always an input, only the input signal is included in the Data Register chain. When the Boundary Scan Data Register is accessed with the SAMPLE/PRELOAD instruction, the input, output, and output enable from each digital pad are sampled and then shifted out of the chain to be verified. The sampling of these values occurs on the rising edge of TCK in the Capture DR state of the TAP controller. While the sampled data is being shifted out of the Boundary Scan chain in the Shift DR state of the TAP controller, new data can be preloaded into the chain for use with the EXTEST and INTEST instructions. These instructions either force data out of the controller, with the EXTEST instruction, or into the controller, with the INTEST instruction. Figure 5-5. Boundary Scan Register Format TDI I N O U T O E ... GPIO PB6 I N O U T GPIO m O E I N RST I N O U T O E ... GPIO m+1 I N O U T O TDO E GPIO n For detailed information on the order of the input, output, and output enable bits for each of the ® GPIO ports, please refer to the Stellaris Family Boundary Scan Description Language (BSDL) files, downloadable from www.luminarymicro.com. 5.4.2.4 APACC Data Register The format for the 35-bit APACC Data Register defined by ARM is described in the ARM® Cortex™-M3 Technical Reference Manual. 5.4.2.5 DPACC Data Register The format for the 35-bit DPACC Data Register defined by ARM is described in the ARM® Cortex™-M3 Technical Reference Manual. 5.4.2.6 ABORT Data Register The format for the 35-bit ABORT Data Register defined by ARM is described in the ARM® Cortex™-M3 Technical Reference Manual. 56 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 6 System Control System control determines the overall operation of the device. It provides information about the device, controls the clocking to the core and individual peripherals, and handles reset detection and reporting. 6.1 Functional Description The System Control module provides the following capabilities: ■ Device identification, see “Device Identification” on page 57 ■ Local control, such as reset (see “Reset Control” on page 57), power (see “Power Control” on page 60) and clock control (see “Clock Control” on page 60) ■ System control (Run, Sleep, and Deep-Sleep modes), see “System Control” on page 62 6.1.1 Device Identification Seven read-only registers provide software with information on the microcontroller, such as version, part number, SRAM size, flash size, and other features. See the DID0, DID1, and DC0-DC4 registers. 6.1.2 Reset Control This section discusses aspects of hardware functions during reset as well as system software requirements following the reset sequence. 6.1.2.1 CMOD0 and CMOD1 Test-Mode Control Pins Two pins, CMOD0 and CMOD1, are defined for use by Luminary Micro for testing the devices during manufacture. They have no end-user function and should not be used. The CMOD pins should be connected to ground. 6.1.2.2 Reset Sources The controller has five sources of reset: 1. External reset input pin (RST) assertion, see “RST Pin Assertion” on page 57. 2. Power-on reset (POR), see “Power-On Reset (POR)” on page 58. 3. Internal brown-out (BOR) detector, see “Brown-Out Reset (BOR)” on page 58. 4. Software-initiated reset (with the software reset registers), see “Software Reset” on page 59. 5. A watchdog timer reset condition violation, see “Watchdog Timer Reset” on page 59. After a reset, the Reset Cause (RESC) register is set with the reset cause. The bits in this register are sticky and maintain their state across multiple reset sequences, except when an internal POR is the cause, and then all the other bits in the RESC register are cleared except for the POR indicator. 6.1.2.3 RST Pin Assertion The external reset pin (RST) resets the controller. This resets the core and all the peripherals except the JTAG TAP controller (see “JTAG Interface” on page 46). The external reset sequence is as follows: June 14, 2007 57 Luminary Micro Confidential-Advance Product Information System Control 1. The external reset pin (RST) is asserted and then de-asserted. 2. The internal reset is released and the core loads from memory the initial stack pointer, the initial program counter, the first instruction designated by the program counter, and begins execution. A few clocks cycles from RST de-assertion to the start of the reset sequence is necessary for synchronization. The external reset timing is shown in Figure 22-11 on page 523. 6.1.2.4 Power-On Reset (POR) The Power-On Reset (POR) circuit monitors the power supply voltage (VDD). The POR circuit generates a reset signal to the internal logic when the power supply ramp reaches a threshold value (VTH). If the application only uses the POR circuit, the RST input needs to be connected to the power supply (VDD) through a pull-up resistor (1K to 10K Ω). The device must be operating within the specified operating parameters at the point when the on-chip power-on reset pulse is complete. The 3.3-V power supply to the device must reach 3.0 V within 10 msec of it crossing 2.0 V to guarantee proper operation. For applications that require the use of an external reset to hold the device in reset longer than the internal POR, the RST input may be used with the circuit as shown in Figure 6-1 on page 58. Figure 6-1. External Circuitry to Extend Reset Stellaris D1 R1 RST C1 R2 The R1 and C1 components define the power-on delay. The R2 resistor mitigates any leakage from the RST input. The diode (D1) discharges C1 rapidly when the power supply is turned off. The Power-On Reset sequence is as follows: 1. The controller waits for the later of external reset (RST) or internal POR to go inactive. 2. The internal reset is released and the core loads from memory the initial stack pointer, the initial program counter, the first instruction designated by the program counter, and begins execution. The internal POR is only active on the initial power-up of the controller. The Power-On Reset timing is shown in Figure 22-12 on page 524. Note: 6.1.2.5 The power-on reset also resets the JTAG controller. An external reset does not. Brown-Out Reset (BOR) A drop in the input voltage resulting in the assertion of the internal brown-out detector can be used to reset the controller. This is initially disabled and may be enabled by software. The system provides a brown-out detection circuit that triggers if the power supply (VDD) drops below a brown-out threshold voltage (VBTH). If a brown-out condition is detected, the system may generate a controller interrupt or a system reset. 58 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Brown-out resets are controlled with the Power-On and Brown-Out Reset Control (PBORCTL) register. The BORIOR bit in the PBORCTL register must be set for a brown-out condition to trigger a reset. The brown-out reset is equivelent to an assertion of the external RST input and the reset is held active until the proper VDD level is restored. The RESC register can be examined in the reset interrupt handler to determine if a Brown-Out condition was the cause of the reset, thus allowing software to determine what actions are required to recover. The internal Brown-Out Reset timing is shown in Figure 22-13 on page 524. 6.1.2.6 Software Reset Software can generate a reset to the entire system or may reset a specific peripheral. Peripherals can be individually reset by software via three registers that control reset signals to each peripheral (see the SRCRn registers). If the bit position corresponding to a peripheral is set, the peripheral is reset. The encoding of the reset registers is consistent with the encoding of the clock gating control for peripherals and on-chip functions (see “System Control” on page 62). Writing a bit lane with a value of 1 initiates a reset of the corresponding unit. Note that all reset signals for all clocks of the specified unit are asserted as a result of a software-initiated reset. The entire system can be reset by software by setting the SYSRESETREQ bit in the Cortex-M3 Application Interrupt and Reset Control register resets the entire system including the core. The software-initiated system reset sequence is as follows: 1. A software system reset is initiated by writing the SYSRESETREQ bit in the ARM Cortex-M3 Application Interrupt and Reset Control register. 2. An internal reset is asserted. 3. The internal reset is deasserted and the controller loads from memory the initial stack pointer, the initial program counter, and the first instruction designated by the program counter, and then begins execution. The software-initiated system reset timing is shown in Figure 22-14 on page 524. 6.1.2.7 Watchdog Timer Reset The watchdog timer module's function is to prevent system hangs. The watchdog timer can be configured to generate an interrupt to the controller on its first time-out, and to generate a reset signal on its second time-out. After the first time-out event, the 32-bit counter is reloaded with the value of the Watchdog Timer Load (WDTLOAD) register, and the timer resumes counting down from that value. If the timer counts down to its zero state again before the first time-out interrupt is cleared, and the reset signal has been enabled, the watchdog timer asserts its reset signal to the system. The watchdog timer reset sequence is as follows: 1. The watchdog timer times out for the second time without being serviced. 2. An internal reset is asserted. 3. The internal reset is released and the controller loads from memory the initial stack pointer, the initial program counter, the first instruction designated by the program counter, and begins execution. June 14, 2007 59 Luminary Micro Confidential-Advance Product Information System Control The watchdog reset timing is shown in Figure 22-15 on page 524. 6.1.3 Power Control ® The Stellaris microcontroller provides an integrated LDO regulator that may be used to provide power to the majority of the controller's internal logic. The LDO regulator provides software a mechanism to adjust the regulated value, in small increments (VSTEP), over the range of 2.25 V to 2.75 V (inclusive)—or 2.5 V ± 10%. The adjustment is made by changing the value of the VADJ field in the LDO Power Control (LDOPCTL) register. Note: 6.1.4 The use of the LDO is optional. The internal logic may be supplied by the on-chip LDO or by an external regulator. If the LDO is used, the LDO output pin is connected to the VDD25 pins on the printed circuit board. The LDO requires decoupling capacitors on the printed circuit board. If an external regulator is used, it is strongly recommended that the external regulator supply the controller only and not be shared with other devices on the printed circuit board. Clock Control System control determines the control of clocks in this part. 6.1.4.1 Fundamental Clock Sources There are four clock sources for use in the device: ■ Internal Oscillator (IOSC): The internal oscillator is an on-chip clock source. It does not require the use of any external components. The frequency of the internal oscillator is 12 MHz ± 30%. Applications that do not depend on accurate clock sources may use this clock source to reduce system cost. The internal oscillator is the clock source the device uses during and following POR. If the main oscillator is required, software must enable the main oscillator following reset and allow the main oscillator to stabilize before changing the clock reference. ■ Main Oscillator: The main oscillator provides a frequency-accurate clock source by one of two means: an external single-ended clock source is connected to the OSC0 input pin, or an external crystal is connected across the OSC0 input and OSC1 output pins. The crystal value allowed depends on whether the main oscillator is used as the clock reference source to the PLL. If so, the crystal must be one of the supported frequencies between 3.579545 MHz through 8.192 MHz (inclusive). If the PLL is not being used, the crystal may be any one of the supported frequencies between 1 MHz and 8.192 MHz. The single-ended clock source range is from DC through the specified speed of the device. The supported crystals are listed in Table 6-3 on page 75. ■ Internal 30-kHz oscillator: The internal 30-kHz oscillator is similar to the internal oscillator, except that it provides an operational frequency of 30 kHz ± 30%. It is intended for use during Deep-Sleep power-saving modes. This power-savings mode benefits from reduced internal switching and also allows the main oscillator to be powered down. ■ External real-time oscillator: The external real-time oscillator provides a low-frequency, accurate clock reference. It is intended to provide the system with a real-time clock source. The real-time oscillator is part of the Hibernation Module (“Hibernation Module” on page 113) and may also provide an accurate source of Deep-Sleep or Hibernate mode power savings. The internal system clock (sysclk), is derived from any of the four sources plus two others: the output of the internal PLL, and the internal oscillator divided by four (3 MHz ± 30%). The frequency of the PLL clock reference must be in the range of 3.579545 MHz to 8.192 MHz (inclusive). 60 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller The Run-Mode Clock Configuration (RCC) and Run-Mode Clock Configuration 2 (RCC2) registers provide control for the system clock. The RCC2 register is provided to extend fields that offer additional encodings over the RCC register. When used, the RCC2 register field values are used by the logic over the corresponding field in the RCC register. In particular, RCC2 provides for a larger assortment of clock configuration options. 6.1.4.2 Crystal Configuration for the Main Oscillator (MOSC) The main oscillator supports the use of a select number of crystals in the range of 1 MHz through 8.192 MHz. This method allows Luminary Micro to provide the best possible PLL settings. Table 6-3 on page 75 describes the available crystal choices and default programming values. Software configures the RCC register XTAL field with the crystal number. If the PLL is used in the design, the XTAL field value is internally translated to the PLL settings. 6.1.4.3 PLL Frequency Configuration The PLL is disabled by default during power-on reset and is enabled later by software if required. Software configures the PLL input reference clock source, specifies the output divisor to set the system clock frequency, and enables the PLL to drive the output. If the main oscillator provides the clock reference to the PLL, the translation provided by hardware and used to program the PLL is available for software in the XTAL to PLL Translation (PLLCFG) register (see page 77). The internal translation provides a translation within ± 1% of the targetted PLL VCO frequency. Table 6-3 on page 75 describes the available crystal choices and default programming of the PLLCFG register. The crystal number is written into the XTAL field of the Run-Mode Clock Configuration (RCC) register. Any time the XTAL field changes, the new settings are translated and the internal PLL settings are updated. 6.1.4.4 PLL Modes The PLL has two modes of operation: Normal and Power-Down ■ Normal: The PLL multiplies the input clock reference and drives the output. ■ Power-Down: Most of the PLL internal circuitry is disabled and the PLL does not drive the output. The modes are programmed using the RCC/RCC2 register fields (see page 73 and page 78). 6.1.4.5 PLL Operation If the PLL configuration is changed, the PLL output frequency is unstable until it reconverges (relocks) to the new setting. The time between the configuration change and relock is TREADY (see Table 22-5 on page 513). During this time, the PLL is not usable as a clock reference. The PLL is changed by one of the following: ■ Change to the XTAL value in the RCC register—writes of the same value do not cause a relock. ■ Change in the PLL from Power-Down to Normal mode. A counter is defined to measure the TREADY requirement. The counter is clocked by the main oscillator. The range of the main oscillator has been taken into account and the down counter is set to 0x1200 (that is, ~600 μs at a 8.192 MHz external oscillator clock). Hardware is provided to keep the PLL from being used as a system clock until the TREADY condition is met after one of the two June 14, 2007 61 Luminary Micro Confidential-Advance Product Information System Control changes above. It is the user's responsibility to have a stable clock source (like the main oscillator) before the RCC/RCC2 register is switched to use the PLL. 6.1.5 System Control For power-savings purposes, the RCGCn , SCGCn , and DCGCn registers control the clock gating logic for each peripheral or block in the system while the controller is in Run, Sleep, and Deep-Sleep mode, respectively. In Run mode, the processor executes code. In Sleep mode, the clock frequency of the active peripherals is unchanged, but the processor is not clocked and therefore no longer executes code. In Deep-Sleep mode, the clock frequency of the active peripherals may change (depending on the Run mode clock configuration) in addition to the processor clock being stopped. An interrupt returns the device to Run mode from one of the sleep modes; the sleep modes are entered on request from the code. Each mode is described in more detail below. There are four levels of operation for the device defined as: ■ Run Mode. Run Mode provides normal operation of the processor and all of the peripherals that are currently enabled by the RCGCn registers. The system clock can be any of the available clock sources including the PLL. ■ Sleep Mode. Sleep mode is entered by the Cortex-M3 core executing a WFI (Wait for Interrupt) instruction. Any properly configured interrupt event in the system will bring the processor back into Run mode. See the system control NVIC section of the ARM® Cortex™-M3 Technical Reference Manual for more details. In Sleep Mode, the Cortex-M3 processor core and the memory subsystem are not clocked. Peripherals are clocked that are enabled in the SCGCn register when auto-clock gating is enabled (see the RCC register) or the RCGCn register when the auto-clock gating is disabled. The system clock has the same source and frequency as that during Run mode. ■ Deep-Sleep Mode. Deep-Sleep mode is entered by first writing the Deep Sleep Enable bit in the ARM Cortex-M3 NVIC system control register and then executing a WFI instruction. Any properly configured interrupt event in the system will bring the processor back into Run mode. See the system control NVIC section of the ARM® Cortex™-M3 Technical Reference Manual for more details. The Cortex-M3 processor core and the memory subsystem are not clocked. Peripherals are clocked that are enabled in the DCGCn register when auto-clock gating is enabled (see the RCC register) or the RCGCn register when auto-clock gating is disabled. The system clock source is the main oscillator by default or the internal oscillator specified in the DSLPCLKCFG register if one is enabled. When the DSLPCLKCFG register is used, the internal oscillator is powered up, if necessary, and the main oscillator is powered down. If the PLL is running at the time of the WFI instruction, hardware will power the PLL down and override the SYSDIV field of the active RCC/RCC2 register to be /16 or /64, respectively. When the Deep-Sleep exit event occurs, hardware brings the system clock back to the source and frequency it had at the onset of Deep-Sleep mode before enabling the clocks that had been stopped during the Deep-Sleep duration. ■ Hibernate Mode. In this mode, the power supplies are turned off to the main part of the device and only the Hibernation module's circuitry is active. An external wake event or RTC event is required to bring the device back to Run mode. The Cortex-M3 processor and peripherals outside of the Hibernation module see a normal "power on" sequence and the processor starts running 62 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller code. It can determine that it has been restarted from Hibernate mode by inspecting the Hibernation module registers. 6.2 Initialization and Configuration The PLL is configured using direct register writes to the RCC/RCC2 register. If the RCC2 register is being used, the USERCC2 bit must be set and the appropriate RCC2 bit/field is used. The steps required to successfully change the PLL-based system clock are: 1. Bypass the PLL and system clock divider by setting the BYPASS bit and clearing the USESYS bit in the RCC register. This configures the system to run off a “raw” clock source (using the main oscillator or internal oscillator) and allows for the new PLL configuration to be validated before switching the system clock to the PLL. 2. Select the crystal value (XTAL) and oscillator source (OSCSRC), and clear the PWRDN bit in RCC/RCC2. Setting the XTAL field automatically pulls valid PLL configuration data for the appropriate crystal, and clearing the PWRDN bit powers and enables the PLL and its output. 3. Select the desired system divider (SYSDIV) in RCC/RCC2 and set the USESYS bit in RCC. The SYSDIV field determines the system frequency for the microcontroller. 4. Wait for the PLL to lock by polling the PLLLRIS bit in the Raw Interrupt Status (RIS) register. 5. Enable use of the PLL by clearing the BYPASS bit in RCC/RCC2. 6.3 Register Map Table 6-1 on page 63 lists the System Control registers, grouped by function. The offset listed is a hexadecimal increment to the register’s address, relative to the System Control base address of 0x400F.E000. Note: Spaces in the System Control register space that are not used are reserved for future or internal use by Luminary Micro, Inc. Software should not modify any reserved memory address. Note: A BV in the Reset column indicates the reset value is a Build Value and part-specific. See the page number referenced for the reset value description. Table 6-1. System Control Register Map Description See page Offset Name Type Reset 0x000 DID0 RO - Device Identification 0 65 0x004 DID1 RO - Device Identification 1 81 0x008 DC0 RO 0x00FF.007F Device Capabilities 0 83 0x010 DC1 RO 0x0101.33FF Device Capabilities 1 84 0x014 DC2 RO 0x070F.5017 Device Capabilities 2 86 0x018 DC3 RO 0x3FFF.7FC0 Device Capabilities 3 88 0x01C DC4 RO 0x5100.007F Device Capabilities 4 90 0x030 PBORCTL R/W 0x0000.7FFD Brown-Out Reset Control 67 June 14, 2007 63 Luminary Micro Confidential-Advance Product Information System Control See page Offset Name Type Reset 0x034 LDOPCTL R/W 0x0000.0000 LDO Power Control 68 0x040 SRCR0 R/W 0x00000000 Software Reset Control 0 109 0x044 SRCR1 R/W 0x00000000 Software Reset Control 1 110 0x048 SRCR2 R/W 0x00000000 Software Reset Control 2 112 0x050 RIS RO 0x0000.0000 Raw Interrupt Status 69 0x054 IMC R/W 0x0000.0000 Interrupt Mask Control 70 0x058 MISC R/W1C 0x0000.0000 Masked Interrupt Status and Clear 71 0x05C RESC R/W - Reset Cause 72 0x060 RCC R/W 0x07A0.3AD1 Run-Mode Clock Configuration 73 0x064 PLLCFG RO - XTAL to PLL Translation 77 0x070 RCC2 R/W 0x0780.2800 Run-Mode Clock Configuration 2 78 0x100 RCGC0 R/W 0x00000040 Run Mode Clock Gating Control Register 0 91 0x104 RCGC1 R/W 0x00000000 Run Mode Clock Gating Control Register 1 97 0x108 RCGC2 R/W 0x00000000 Run Mode Clock Gating Control Register 2 103 0x110 SCGC0 R/W 0x00000040 Sleep Mode Clock Gating Control Register 0 93 0x114 SCGC1 R/W 0x00000000 Sleep Mode Clock Gating Control Register 1 99 0x118 SCGC2 R/W 0x00000000 Sleep Mode Clock Gating Control Register 2 105 0x120 DCGC0 R/W 0x00000040 Deep Sleep Mode Clock Gating Control Register 0 95 0x124 DCGC1 R/W 0x00000000 Deep Sleep Mode Clock Gating Control Register 1 101 0x128 DCGC2 R/W 0x00000000 Deep Sleep Mode Clock Gating Control Register 2 107 0x144 DSLPCLKCFG R/W 0x0780.0000 Deep Sleep Clock Configuration 80 6.4 Description Register Descriptions All addresses given are relative to the System Control base address of 0x400F.E000. 64 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 1: Device Identification 0 (DID0), offset 0x000 This register identifies the version of the device. Device Identification 0 (DID0) Base 0x400F.E000 Offset 0x000 Type RO, reset 31 30 reserved Type Reset 29 28 27 26 VER 25 24 23 22 21 20 reserved 18 17 16 CLASS RO 0 RO 0 RO 0 RO 1 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO - RO - RO - RO - RO - RO - RO - RO - RO - RO - RO - RO - RO - RO - RO - RO - MAJOR Type Reset 19 MINOR Bit/Field Name Type Reset Description 31 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 30:28 VER RO 1 This field defines the DID0 register format version. The version number is numeric. The value of the VER field is encoded as follows: Value Description 1 First revision of the DID0 register format, for Stellaris® Fury-class devices. 27:24 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 23:16 CLASS RO 1 The CLASS field value identifies the internal design from which all mask sets are generated for all devices in a particular product line. The CLASS field value is changed for new product lines, for changes in fab process (for example, a remap or shrink), or any case where the MAJOR or MINOR fields require differentiation from prior devices. The value of the CLASS field is encoded as follows (all other encodings are reserved): Value Description 0 Stellaris® Sandstorm-class devices. 1 Stellaris® Fury-class devices. June 14, 2007 65 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset 15:8 MAJOR RO - Description This field specifies the major revision number of the device. The major revision reflects changes to base layers of the design. The major revision number is indicated in the part number as a letter (A for first revision, B for second, and so on). This field is encoded as follows: Value Description 0 Revision A (initial device) 1 Revision B (first base layer revision) 2 Revision C (second base layer revision) and so on. 7:0 MINOR RO - This field specifies the minor revision number of the device. The minor revision reflects changes to the metal layers of the design. The MINOR field value is reset when the MAJOR field is changed. This field is numeric and is encoded as follows: Value Description 0 Initial device, or a major revision update. 1 First metal layer change. 2 Second metal layer change. and so on. 66 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: Brown-Out Reset Control (PBORCTL), offset 0x030 This register is responsible for controlling reset conditions after initial power-on reset. Brown-Out Reset Control (PBORCTL) Base 0x400F.E000 Offset 0x030 Type R/W, reset 0x0000.7FFD 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset BORIOR reserved R/W 0 RO 0 Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 BORIOR R/W 0 BOR Interrupt or Reset This bit controls how a BOR event is signaled to the controller. If set, a reset is signaled. Otherwise, an interrupt is signaled. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 67 Luminary Micro Confidential-Advance Product Information System Control Register 3: LDO Power Control (LDOPCTL), offset 0x034 The VADJ field in this register adjusts the on-chip output voltage (VOUT). LDO Power Control (LDOPCTL) Base 0x400F.E000 Offset 0x034 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset VADJ RO 0 Bit/Field Name Type Reset Description 31:6 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5:0 VADJ R/W 0x0 This field sets the on-chip output voltage. The programming values for the VADJ field are provided in Table 6-2 on page 68. Table 6-2. VADJ to VOUT VADJ Value VOUT (V) VADJ Value VOUT (V) VADJ Value VOUT (V) 0x1B 2.75 0x1F 2.55 0x03 2.35 0x1C 2.70 0x00 2.50 0x04 2.30 0x1D 2.65 0x01 2.45 0x05 2.25 0x1E 2.60 0x02 2.40 0x06-0x3F Reserved 68 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 4: Raw Interrupt Status (RIS), offset 0x050 Central location for system control raw interrupts. These are set and cleared by hardware. Raw Interrupt Status (RIS) Base 0x400F.E000 Offset 0x050 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 PLLLRIS RO 0 reserved BORRIS reserved RO 0 RO 0 Bit/Field Name Type Reset Description 31:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 PLLLRIS RO 0 PLL Lock Raw Interrupt Status This bit is set when the PLL TREADY Timer asserts. 5:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 BORRIS RO 0 Brown-Out Reset Raw Interrupt Status This bit is the raw interrupt status for any brown-out conditions. If set, a brown-out condition is currently active. This is an unregistered signal from the brown-out detection circuit. An interrupt is reported if the BORIM bit in the IMC register is set and the BORIOR bit in the PBORCTL register is cleared. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 69 Luminary Micro Confidential-Advance Product Information System Control Register 5: Interrupt Mask Control (IMC), offset 0x054 Central location for system control interrupt masks. Interrupt Mask Control (IMC) Base 0x400F.E000 Offset 0x054 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 BORIM reserved RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 RO 0 reserved Type Reset reserved Type Reset RO 0 PLLLIM R/W 0 reserved Bit/Field Name Type Reset Description 31:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 PLLLIM R/W 0 PLL Lock Interrupt Mask This bit specifies whether a current limit detection is promoted to a controller interrupt. If set, an interrupt is generated if PLLLRIS in RIS is set; otherwise, an interrupt is not generated. 5:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 BORIM R/W 0 Brown-Out Reset Interrupt Mask This bit specifies whether a brown-out condition is promoted to a controller interrupt. If set, an interrupt is generated if BORRIS is set; otherwise, an interrupt is not generated. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 70 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: Masked Interrupt Status and Clear (MISC), offset 0x058 Central location for system control result of RIS AND IMC to generate an interrupt to the controller. All of the bits are R/W1C and this action also clears the corresponding raw interrupt bit in the RIS register (see page 69). Masked Interrupt Status and Clear (MISC) Base 0x400F.E000 Offset 0x058 Type R/W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 PLLLMIS R/W1C 0 reserved BORMIS reserved R/W1C 0 RO 0 Bit/Field Name Type Reset Description 31:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 PLLLMIS R/W1C 0 PLL Lock Masked Interrupt Status This bit is set when the PLL TREADY timer asserts. The interrupt is cleared by writing a 1 to this bit. 5:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 BORMIS R/W1C 0 The BORMIS is simply the BORRIS ANDed with the mask value, BORIM. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 71 Luminary Micro Confidential-Advance Product Information System Control Register 7: Reset Cause (RESC), offset 0x05C This register is set with the reset cause after reset. The bits in this register are sticky and maintain their state across multiple reset sequences, except when an external reset is the cause, and then all the other bits in the RESC register are cleared. Reset Cause (RESC) Base 0x400F.E000 Offset 0x05C Type R/W, reset 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 LDO SW WDT BOR POR EXT RO 0 RO 0 RO 0 R/W - R/W - R/W - R/W - R/W - R/W - reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset Description 31:6 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5 LDO R/W - When set, indicates the LDO circuit has lost regulation and has generated a reset event. 4 SW R/W - When set, indicates a software reset is the cause of the reset event. 3 WDT R/W - When set, indicates a watchdog reset is the cause of the reset event. 2 BOR R/W - When set, indicates a brown-out reset is the cause of the reset event. 1 POR R/W - When set, indicates a power-on reset is the cause of the reset event. 0 EXT R/W - When set, indicates an external reset (RST assertion) is the cause of the reset event. 72 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 8: Run-Mode Clock Configuration (RCC), offset 0x060 This register is defined to provide source control and frequency speed. Run-Mode Clock Configuration (RCC) Base 0x400F.E000 Offset 0x060 Type R/W, reset 0x07A0.3AD1 31 30 29 28 RO 0 RO 0 RO 0 RO 0 15 14 13 12 reserved Type Reset reserved Type Reset RO 0 RO 1 27 26 25 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 11 10 9 8 R/W 1 R/W 0 ACG 24 RO 1 R/W 1 21 20 19 R/W 0 RO 0 RO 0 RO 0 7 6 5 4 3 R/W 1 R/W 1 R/W 0 SYSDIV RO 0 22 USESYSDIV PWRDN reserved BYPASS reserved R/W 1 23 XTAL Bit/Field Name Type Reset 31:28 reserved RO 0x0 27 ACG R/W 0 18 17 16 RO 0 RO 0 RO 0 2 1 0 reserved OSCSRC R/W 1 reserved RO 0 RO 0 IOSCDIS MOSCDIS R/W 0 R/W 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Auto Clock Gating This bit specifies whether the system uses the Sleep-Mode Clock Gating Control (SCGCn) registers and Deep-Sleep-Mode Clock Gating Control (DCGCn) registers if the controller enters a Sleep or Deep-Sleep mode (respectively). If set, the SCGCn or DCGCn registers are used to control the clocks distributed to the peripherals when the controller is in a sleep mode. Otherwise, the Run-Mode Clock Gating Control (RCGCn) registers are used when the controller enters a sleep mode. The RCGCn registers are always used to control the clocks in Run mode. This allows peripherals to consume less power when the controller is in a sleep mode and the peripheral is unused. June 14, 2007 73 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset 26:23 SYSDIV R/W 0xF Description System Clock Divisor Specifies which divisor is used to generate the system clock from the PLL output. The PLL VCO frequency is 400 MHz. Binary Value Divisor (BYPASS=1) Frequency (BYPASS=0) 0000-0010 reserved reserved 0011 /8 50 MHz 0100 /10 40 MHz 0101 /12 33.33 MHz 0110 /14 28.57 MHz 0111 /16 25 MHz 1000 /18 22.22 MHz 1001 /20 20 MHz 1010 /22 18.18 MHz 1011 /24 16.67 MHz 1100 /26 15.38 MHz 1101 /28 14.29 MHz 1110 /30 13.33 MHz 1111 /32 12.5 MHz (default) When reading the Run-Mode Clock Configuration (RCC) register (see page 73), the SYSDIV value is MINSYSDIV if a lower divider was requested and the PLL is being used. This lower value is allowed to divide a non-PLL source. 22 USESYSDIV R/W 0 Use the system clock divider as the source for the system clock. The system clock divider is forced to be used when the PLL is selected as the source. 21:14 reserved RO 1 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 13 PWRDN R/W 1 PLL Power Down This bit connects to the PLL PWRDN input. The reset value of 1 powers down the PLL. 12 reserved RO 1 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 74 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset Description 11 BYPASS R/W 1 PLL Bypass Chooses whether the system clock is derived from the PLL output or the OSC source. If set, the clock that drives the system is the OSC source. Otherwise, the clock that drives the system is the PLL output clock divided by the system divider. Note: The ADC must be clocked from the PLL or directly from a 14-MHz to 18-MHz clock source to operate properly. While the ADC works in a 14-18 MHz range, to maintain a 1 M sample/second rate, the ADC must be provided a 16-MHz clock source. 10 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9:6 XTAL R/W 0xB This field specifies the crystal value attached to the main oscillator. The encoding for this field is provided in Table 6-3 on page 75. 5:4 OSCSRC R/W 0x1 Picks among the four input sources for the OSC. The values are: Value Input Source 3:2 reserved RO 0x0 1 IOSCDIS R/W 0 00 Main oscillator (default) 01 Internal oscillator (default) 10 Internal oscillator / 4 (this is necessary if used as input to PLL) 11 reserved Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Internal Oscillator (IOSC) Disable 0: Internal oscillator is enabled. 1: Internal oscillator is disabled. 0 MOSCDIS R/W 1 Main Oscillator Disable 0: Main oscillator is enabled. 1: Main oscillator is disabled (default). Table 6-3. Default Crystal Field Values and PLL Programming Crystal Number (XTAL Binary Value) Crystal Frequency (MHz) Not Using the PLL Crystal Frequency (MHz) Using the PLL 0000 1.000 reserved 0001 1.8432 reserved 0010 2.000 reserved 0011 2.4576 reserved 0100 3.579545 MHz 0101 3.6864 MHz 0110 4 MHz 0111 4.096 MHz June 14, 2007 75 Luminary Micro Confidential-Advance Product Information System Control Crystal Number (XTAL Binary Value) Crystal Frequency (MHz) Not Using the PLL Crystal Frequency (MHz) Using the PLL 1000 4.9152 MHz 1001 5 MHz 1010 5.12 MHz 1011 6 MHz (reset value) 1100 6.144 MHz 1101 7.3728 MHz 1110 8 MHz 1111 8.192 MHz 76 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 9: XTAL to PLL Translation (PLLCFG), offset 0x064 This register provides a means of translating external crystal frequencies into the appropriate PLL settings. This register is initialized during the reset sequence and updated anytime that the XTAL field changes in the Run-Mode Clock Configuration (RCC) register (see page 73). The PLL frequency is calculated using the PLLCFG field values, as follows: PLLFreq = OSCFreq * F / (R + 1) XTAL to PLL Translation (PLLCFG) Base 0x400F.E000 Offset 0x064 Type RO, reset 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO - RO - RO - RO - RO - RO - 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO - RO - RO - RO - RO - RO - RO - RO - RO - reserved Type Reset OD Type Reset RO - F R Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:14 OD RO - This field specifies the value supplied to the PLL’s OD input. 13:5 F RO - This field specifies the value supplied to the PLL’s F input. 4:0 R RO - This field specifies the value supplied to the PLL’s R input. June 14, 2007 77 Luminary Micro Confidential-Advance Product Information System Control Register 10: Run-Mode Clock Configuration 2 (RCC2), offset 0x070 This register overrides the RCC equivalent register fields when the USERCC2 bit is set. This allows RCC2 to be used to extend the capabilities, while also providing a means to be backward-compatible to previous parts. The fields within the RCC2 register occupy the same bit positions as they do within the RCC register as LSB-justified. The SYSDIV2 field is wider so that additional larger divisors are possible. This allows a lower system clock frequency for improved Deep Sleep power consumption. Run-Mode Clock Configuration 2 (RCC2) Base 0x400F.E000 Offset 0x070 Type R/W, reset 0x0780.2800 31 30 USERCC2 Type Reset R/W 0 RO 0 15 14 reserved Type Reset RO 0 29 28 27 reserved RO 0 26 25 24 23 22 21 20 SYSDIV2 RO 0 R/W 0 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 RO 0 13 12 11 10 9 8 7 6 PWRDN2 reserved BYPASS2 R/W 1 RO 0 R/W 1 reserved RO 0 19 18 17 16 reserved RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 5 4 3 2 1 0 RO 0 RO 0 OSCSRC2 RO 0 R/W 0 R/W 0 reserved R/W 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31 USERCC2 R/W 0 When set, overrides the RCC register fields. 30:29 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 28:23 SYSDIV2 R/W 0x0F System Clock Divisor (6-bit) Specifies which divisor is used to generate the system clock from the PLL output. The PLL VCO frequency is 400 MHz. This field is wider than the RCC register SYSDIV field in order to provide additional divisor values. This permits the system clock to be run at much lower frequencies during Deep Sleep mode. For example, where the RCC register SYSDIV encoding of 111 provides /16, the RCC2 register SYSDIV2 encoding of 111111 provides /64. 22:14 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 13 PWRDN2 R/W 1 When set, powers down the PLL. 12 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 11 BYPASS2 R/W 1 When set, bypasses the PLL for the clock source. 10:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 78 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 6:4 OSCSRC2 R/W 0 Description System Clock Source Name 3:0 reserved RO 0 Value Description MOSC 0 Main oscillator IOSC Internal oscillator 1 IOSC/4 2 Internal oscillator / 4 30kHz 3 30 kHz internal oscillator 32kHz 7 32 kHz external oscillator Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 79 Luminary Micro Confidential-Advance Product Information System Control Register 11: Deep Sleep Clock Configuration (DSLPCLKCFG), offset 0x144 This register provides configuration information for the hardware control of Deep Sleep Mode. Deep Sleep Clock Configuration (DSLPCLKCFG) Base 0x400F.E000 Offset 0x144 Type R/W, reset 0x0780.0000 31 30 29 28 27 26 reserved Type Reset 25 24 23 22 21 20 DSDIVORIDE 18 17 16 reserved RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset 19 RO 0 DSOSCSRC R/W 0 reserved Bit/Field Name Type Reset Description 31:29 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 28:23 DSDIVORIDE R/W 0x0F 6-bit system divider field to override when Deep-Sleep occurs with PLL running. 22:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6:4 DSOSCSRC R/W 0 When set, forces IOSC to be clock source during Deep Sleep mode. Name 3:0 reserved RO 0 Value Description NOORIDE 0 No override to the oscillator clock source is done IOSC 1 Use internal 12 MHz oscillator as source 30kHz 3 Use 30 kHz internal oscillator 32kHz 7 Use 32 kHz external oscillator Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 80 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 12: Device Identification 1 (DID1), offset 0x004 This register identifies the device family, part number, temperature range, pin count, and package type. Device Identification 1 (DID1) Base 0x400F.E000 Offset 0x004 Type RO, reset 31 30 29 28 27 26 RO 0 15 25 24 23 22 21 20 RO 0 RO 0 RO 1 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 0 RO 0 14 13 12 11 10 9 8 7 6 5 4 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 VER Type Reset FAM PINCOUNT Type Reset RO 0 RO 1 18 17 16 RO 1 RO 0 RO 0 RO 0 3 2 1 0 PARTNO reserved RO 0 19 TEMP Bit/Field Name Type Reset 31:28 VER RO 0x1 RO 0 PKG ROHS RO 1 RO 1 QUAL RO - RO - Description This field defines the DID1 register format version. The version number is numeric. The value of the VER field is encoded as follows (all other encodings are reserved): Value Description 0x1 27:24 FAM RO 0x0 First revision of the DID1 register format, indicating a Stellaris LM3Snnnn device. Family This field provides the family identification of the device within the Luminary Micro product portfolio. The value is encoded as follows (all other encodings are reserved): Value Description 0x0 23:16 PARTNO RO 0x88 Stellaris family of microcontollers, that is, all devices with external part numbers starting with LM3S. Part Number This field provides the part number of the device within the family. The value is encoded as follows (all other encodings are reserved): Value Description 0x88 LM3S8938 15:13 PINCOUNT RO 0x2 Package Pin Count This field specifies the number of pins on the device package. The value is encoded as follows (all other encodings are reserved): Value Description 0x2 100-pin package June 14, 2007 81 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset 12:8 reserved RO 0 7:5 TEMP RO 0x1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Temperature Range This field specifies the temperature rating of the device. The value is encoded as follows (all other encodings are reserved): Value Description 0x1 4:3 PKG RO 0x1 Industrial temperature range (-40C to 85C) Package Type This field specifies the package type. The value is encoded as follows (all other encodings are reserved): Value Description 0x1 2 ROHS RO 1 LQFP package RoHS-Compliance This bit specifies whether the device is RoHS-compliant. A 1 indicates the part is RoHS-compliant. 1:0 QUAL RO - Qualification Status This field specifies the qualification status of the device. The value is encoded as follows (all other encodings are reserved): Value Description 0x0 Engineering Sample (unqualified) 0x1 Pilot Production (unqualified) 0x2 Fully Qualified 82 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 13: Device Capabilities 0 (DC0), offset 0x008 This register is predefined by the part and can be used to verify features. Device Capabilities 0 (DC0) Base 0x400F.E000 Offset 0x008 Type RO, reset 0x00FF.007F 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 7 6 5 4 3 2 1 0 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 SRAMSZ Type Reset FLASHSZ Type Reset RO 0 Bit/Field Name Type Reset Description 31:16 SRAMSZ RO 0x00FF SRAM Size Indicates the size of the on-chip SRAM memory. Value Description 0x00FF 64 KB of SRAM 15:0 FLASHSZ RO 0x007F Flash Size Indicates the size of the on-chip flash memory. Value Description 0x007F 256 KB of Flash June 14, 2007 83 Luminary Micro Confidential-Advance Product Information System Control Register 14: Device Capabilities 1 (DC1), offset 0x010 This register is predefined by the part and can be used to verify features. The PWM, SARADC0, MAXADCSPD, WDT, SWO, SWD, and JTAG bits mask the RCGC0, SCGC0, and DCGC0 registers. Other bits are passed as 0. MAXADCSPD is clipped to the maximum value specified in DC1. Device Capabilities 1 (DC1) Base 0x400F.E000 Offset 0x010 Type RO, reset 0x0101.33FF 31 30 29 RO 0 RO 0 RO 0 15 14 13 RO 0 RO 0 28 27 26 25 RO 0 RO 0 RO 0 RO 0 12 11 10 9 RO 1 RO 0 reserved Type Reset 23 22 21 RO 1 RO 0 RO 0 RO 0 8 7 6 MPU RO 1 MAXADCSPD RO 1 19 18 17 RO 0 RO 0 RO 0 RO 0 RO 1 5 4 3 2 1 0 HIB TEMPSNS PLL WDT SWO SWD JTAG RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 CAN0 SYSDIV Type Reset 24 RO 0 RO 1 RO 1 20 reserved 16 SARADC0 Bit/Field Name Type Reset Description 31:25 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 24 CAN0 RO 1 When set, indicates that CAN unit 0 is present. 23:17 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 16 SARADC0 RO 1 When set, indicates that general SAR ADC 0 is present. 15:12 SYSDIV RO 0x3 Minimum 4-bit divider value for system clock. The reset value is hardware-dependent. See the RCC register for how to change the system clock divisor using the SYSDIV bit. Value Description 0x3 11:8 MAXADCSPD RO 0x3 Specifies a 50-MHz CPU clock with a PLL divider of 4. This field indicates the maximum rate at which the ADC samples data. Value Description 0x3 1M samples/second 7 MPU RO 1 When set, indicates that the Cortex-M3 Memory Protection Unit (MPU) module is present. See the ARM Cortex-M3 Technical Reference Manual for details on the MPU. 6 HIB RO 1 When set, indicates that the Hibernation module is present. 5 TEMPSNS RO 1 When set, indicates that the on-chip temperature sensor is present. 4 PLL RO 1 When set, indicates that the on-chip Phase Locked Loop (PLL) is present. 84 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset Description 3 WDT RO 1 When set, indicates that a watchdog timer is present. 2 SWO RO 1 When set, indicates that the Serial Wire Output (SWO) trace port is present. 1 SWD RO 1 When set, indicates that the Serial Wire Debugger (SWD) is present. 0 JTAG RO 1 When set, indicates that the JTAG debugger interface is present. June 14, 2007 85 Luminary Micro Confidential-Advance Product Information System Control Register 15: Device Capabilities 2 (DC2), offset 0x014 This register is predefined by the part and can be used to verify features. Device Capabilities 2 (DC2) Base 0x400F.E000 Offset 0x014 Type RO, reset 0x070F.5017 31 30 RO 0 RO 0 15 29 28 27 26 25 24 RO 0 RO 0 RO 0 COMP2 COMP1 COMP0 RO 1 RO 1 14 13 12 11 10 9 reserved I2C1 reserved I2C0 RO 0 RO 1 RO 0 RO 1 RO 0 RO 0 RO 0 reserved Type Reset Type Reset 23 22 21 RO 1 RO 0 RO 0 RO 0 RO 0 8 7 6 5 19 18 17 16 TIMER3 TIMER2 TIMER1 TIMER0 RO 1 RO 1 RO 1 RO 1 4 3 2 1 0 RO 0 RO 0 RO 0 SSI0 reserved UART2 UART1 UART0 RO 1 RO 0 RO 1 RO 1 RO 1 reserved reserved RO 0 20 Bit/Field Name Type Reset Description 31:27 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 26 COMP2 RO 1 When set, indicates that analog comparator 2 is present. 25 COMP1 RO 1 When set, indicates that analog comparator 1 is present. 24 COMP0 RO 1 When set, indicates that analog comparator 0 is present. 23:20 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 19 TIMER3 RO 1 When set, indicates that General-Purpose Timer module 3 is present. 18 TIMER2 RO 1 When set, indicates that General-Purpose Timer module 2 is present. 17 TIMER1 RO 1 When set, indicates that General-Purpose Timer module 1 is present. 16 TIMER0 RO 1 When set, indicates that General-Purpose Timer module 0 is present. 15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14 I2C1 RO 1 When set, indicates that I2C module 1 is present. 13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 I2C0 RO 1 When set, indicates that I2C module 0 is present. 11:5 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 SSI0 RO 1 When set, indicates that SSI module 0 is present. 86 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset Description 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 UART2 RO 1 When set, indicates that UART module 2 is present. 1 UART1 RO 1 When set, indicates that UART module 1 is present. 0 UART0 RO 1 When set, indicates that UART module 0 is present. June 14, 2007 87 Luminary Micro Confidential-Advance Product Information System Control Register 16: Device Capabilities 3 (DC3), offset 0x018 This register is predefined by the part and can be used to verify features. Device Capabilities 3 (DC3) Base 0x400F.E000 Offset 0x018 Type RO, reset 0x3FFF.7FC0 31 30 reserved 29 28 27 26 25 24 23 22 21 20 19 18 17 16 CCP5 CCP4 CCP3 CCP2 CCP1 CCP0 ADC7 ADC6 ADC5 ADC4 ADC3 ADC2 ADC1 ADC0 RO 0 RO 0 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 reserved C2O RO 0 RO 1 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Type Reset Type Reset C2PLUS C2MINUS RO 1 RO 1 C1O RO 1 C1PLUS C1MINUS RO 1 RO 1 C0O RO 1 C0PLUS C0MINUS RO 1 RO 1 reserved Bit/Field Name Type Reset Description 31:30 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 29 CCP5 RO 1 When set, indicates that Capture/Compare/PWM pin 5 is present. 28 CCP4 RO 1 When set, indicates that Capture/Compare/PWM pin 4 is present. 27 CCP3 RO 1 When set, indicates that Capture/Compare/PWM pin 3 is present. 26 CCP2 RO 1 When set, indicates that Capture/Compare/PWM pin 2 is present. 25 CCP1 RO 1 When set, indicates that Capture/Compare/PWM pin 1 is present. 24 CCP0 RO 1 When set, indicates that Capture/Compare/PWM pin 0 is present. 23 ADC7 RO 1 When set, indicates that ADC pin 7 is present. 22 ADC6 RO 1 When set, indicates that ADC pin 6 is present. 21 ADC5 RO 1 When set, indicates that ADC pin 5 is present. 20 ADC4 RO 1 When set, indicates that ADC pin 4 is present. 19 ADC3 RO 1 When set, indicates that ADC pin 3 is present. 18 ADC2 RO 1 When set, indicates that ADC pin 2 is present. 17 ADC1 RO 1 When set, indicates that ADC pin 1 is present. 16 ADC0 RO 1 When set, indicates that ADC pin 0 is present. 15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14 C2O RO 1 When set, indicates that the analog comparator 2 output pin is present. 13 C2PLUS RO 1 When set, indicates that the analog comparator 2 (+) input pin is present. 12 C2MINUS RO 1 When set, indicates that the analog comparator 2 (-) input pin is present. 88 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset Description 11 C1O RO 1 When set, indicates that the analog comparator 1 output pin is present. 10 C1PLUS RO 1 When set, indicates that the analog comparator 1 (+) input pin is present. 9 C1MINUS RO 1 When set, indicates that the analog comparator 1 (-) input pin is present. 8 C0O RO 1 When set, indicates that the analog comparator 0 output pin is present. 7 C0PLUS RO 1 When set, indicates that the analog comparator 0 (+) input pin is present. 6 C0MINUS RO 1 When set, indicates that the analog comparator 0 (-) input pin is present. 5:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 89 Luminary Micro Confidential-Advance Product Information System Control Register 17: Device Capabilities 4 (DC4), offset 0x01C This register is predefined by the part and can be used to verify features. Device Capabilities 4 (DC4) Base 0x400F.E000 Offset 0x01C Type RO, reset 0x5100.007F 31 30 29 28 reserved EPHY0 reserved EMAC0 RO 0 RO 1 RO 0 RO 1 RO 0 RO 0 RO 0 15 14 13 12 11 10 RO 0 RO 0 RO 0 RO 0 RO 0 Type Reset 27 26 25 23 22 21 20 RO 1 RO 0 RO 0 RO 0 RO 0 9 8 7 6 5 GPIOG RO 0 RO 0 RO 0 RO 1 reserved 24 RO 0 17 16 RO 0 RO 0 RO 0 RO 0 4 3 2 1 0 GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 reserved reserved Type Reset 18 E1588 19 Bit/Field Name Type Reset Description 31 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 30 EPHY0 RO 1 When set, indicates that Ethernet PHY module 0 is present. 29 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 28 EMAC0 RO 1 When set, indicates that Ethernet MAC module 0 is present. 27:25 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 24 E1588 RO 1 When set, indicates that that EMAC0 is 1588-capable. 23:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 GPIOG RO 1 When set, indicates that GPIO Port G is present. 5 GPIOF RO 1 When set, indicates that GPIO Port F is present. 4 GPIOE RO 1 When set, indicates that GPIO Port E is present. 3 GPIOD RO 1 When set, indicates that GPIO Port D is present. 2 GPIOC RO 1 When set, indicates that GPIO Port C is present. 1 GPIOB RO 1 When set, indicates that GPIO Port B is present. 0 GPIOA RO 1 When set, indicates that GPIO Port A is present. 90 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 18: Run Mode Clock Gating Control Register 0 (RCGC0), offset 0x100 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC0 is the clock configuration register for running operation, SCGC0 for Sleep operation, and DCGC0 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. Run Mode Clock Gating Control Register 0 (RCGC0) Base 0x400F.E000 Offset 0x100 Type R/W, reset 0x00000040 31 30 29 RO 0 RO 0 RO 0 15 14 13 RO 0 RO 0 28 27 26 25 RO 0 RO 0 RO 0 RO 0 12 11 10 9 RO 0 R/W 0 R/W 0 reserved Type Reset 23 22 21 R/W 0 RO 0 RO 0 RO 0 8 7 6 5 CAN0 reserved Type Reset 24 MAXADCSPD RO 0 R/W 0 R/W 0 20 19 18 17 RO 0 RO 0 RO 0 RO 0 R/W 0 4 3 2 1 0 reserved reserved HIB RO 0 R/W 0 reserved RO 0 RO 0 16 SARADC0 WDT R/W 0 reserved RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:25 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 24 CAN0 R/W 0 This bit controls the clock gating for CAN unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. 23:17 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 16 SARADC0 R/W 0 This bit controls the clock gating for SAR ADC module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, a read or write to the unit generates a bus fault. 15:12 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 91 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset 11:8 MAXADCSPD R/W 0 Description This field sets the rate at which the ADC samples data. You cannot set the rate higher than the maximum rate. You can set the sample rate by setting the MAXADCSPD bit as follows: Value Description 0x3 1M samples/second 0x2 500K samples/second 0x1 250K samples/second 0x0 125K samples/second 7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 HIB R/W 0 This bit controls the clock gating for the Hibernation module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. 5:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 WDT R/W 0 This bit controls the clock gating for the WDT module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, a read or write to the unit generates a bus fault. 2:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 92 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 19: Sleep Mode Clock Gating Control Register 0 (SCGC0), offset 0x110 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC0 is the clock configuration register for running operation, SCGC0 for Sleep operation, and DCGC0 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. bit was changed to Sleep Mode Clock Gating Control Register 0 (SCGC0) Base 0x400F.E000 Offset 0x110 Type R/W, reset 0x00000040 31 30 29 28 27 26 25 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 reserved Type Reset RO 0 RO 0 24 RO 0 RO 0 R/W 0 10 9 8 MAXADCSPD RO 0 RO 0 23 22 21 CAN0 R/W 0 R/W 0 R/W 0 R/W 0 20 19 18 17 reserved RO 0 RO 0 RO 0 RO 0 5 4 7 6 reserved HIB RO 0 R/W 0 reserved RO 0 RO 0 16 SARADC0 RO 0 RO 0 3 2 WDT R/W 0 RO 0 R/W 0 1 0 reserved RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:25 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 24 CAN0 R/W 0 This bit controls the clock gating for CAN unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. 23:17 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 16 SARADC0 R/W 0 This bit controls the clock gating for general SAR ADC module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, a read or write to the unit generates a bus fault. 15:12 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 93 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset 11:8 MAXADCSPD R/W 0 Description This field sets the rate at which the ADC samples data. You cannot set the rate higher than the maximum rate.You can set the sample rate by setting the MAXADCSPD bit as follows: Value Description 0x3 1M samples/second 0x2 500K samples/second 0x1 250K samples/second 0x0 125K samples/second 7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 HIB R/W 0 This bit controls the clock gating for the Hibernation module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. 5:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 WDT R/W 0 This bit controls the clock gating for the WDT module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, a read or write to the unit generates a bus fault. 2:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 94 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 20: Deep Sleep Mode Clock Gating Control Register 0 (DCGC0), offset 0x120 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC0 is the clock configuration register for running operation, SCGC0 for Sleep operation, and DCGC0 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. bit was changed to Deep Sleep Mode Clock Gating Control Register 0 (DCGC0) Base 0x400F.E000 Offset 0x120 Type R/W, reset 0x00000040 31 30 29 28 27 26 25 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 reserved Type Reset RO 0 RO 0 24 RO 0 RO 0 R/W 0 10 9 8 MAXADCSPD RO 0 RO 0 23 22 21 CAN0 R/W 0 R/W 0 R/W 0 R/W 0 20 19 18 17 reserved RO 0 RO 0 RO 0 RO 0 5 4 7 6 reserved HIB RO 0 R/W 0 reserved RO 0 RO 0 16 SARADC0 RO 0 RO 0 3 2 WDT R/W 0 RO 0 R/W 0 1 0 reserved RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:25 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 24 CAN0 R/W 0 This bit controls the clock gating for CAN unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. 23:17 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 16 SARADC0 R/W 0 This bit controls the clock gating for general SAR ADC module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, a read or write to the unit generates a bus fault. 15:12 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 95 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset 11:8 MAXADCSPD R/W 0 Description This field sets the rate at which the ADC samples data. You cannot set the rate higher than the maximum rate. You can set the sample rate by setting the MAXADCSPD bit as follows: Value Description 0x3 1M samples/second 0x2 500K samples/second 0x1 250K samples/second 0x0 125K samples/second 7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 HIB R/W 0 This bit controls the clock gating for the Hibernation module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. 5:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 WDT R/W 0 This bit controls the clock gating for the WDT module. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, a read or write to the unit generates a bus fault. 2:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 96 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 21: Run Mode Clock Gating Control Register 1 (RCGC1), offset 0x104 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC1 is the clock configuration register for running operation, SCGC1 for Sleep operation, and DCGC1 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. Run Mode Clock Gating Control Register 1 (RCGC1) Base 0x400F.E000 Offset 0x104 Type R/W, reset 0x00000000 31 30 RO 0 RO 0 15 29 28 27 26 25 24 RO 0 RO 0 RO 0 COMP2 COMP1 COMP0 R/W 0 R/W 0 14 13 12 11 10 9 reserved I2C1 reserved I2C0 RO 0 R/W 0 RO 0 R/W 0 RO 0 RO 0 RO 0 reserved Type Reset Type Reset 23 22 21 R/W 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 19 18 17 16 TIMER3 TIMER2 TIMER1 TIMER0 R/W 0 R/W 0 R/W 0 R/W 0 4 3 2 1 0 RO 0 RO 0 RO 0 SSI0 reserved UART2 UART1 UART0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 reserved reserved RO 0 20 Bit/Field Name Type Reset Description 31:27 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 26 COMP2 R/W 0 This bit controls the clock gating for analog comparator 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 25 COMP1 R/W 0 This bit controls the clock gating for analog comparator 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 24 COMP0 R/W 0 This bit controls the clock gating for analog comparator 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 23:20 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 19 TIMER3 R/W 0 This bit controls the clock gating for General-Purpose Timer module 3. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. June 14, 2007 97 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset Description 18 TIMER2 R/W 0 This bit controls the clock gating for General-Purpose Timer module 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 17 TIMER1 R/W 0 This bit controls the clock gating for General-Purpose Timer module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 16 TIMER0 R/W 0 This bit controls the clock gating for General-Purpose Timer module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14 I2C1 R/W 0 This bit controls the clock gating for I2C module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 I2C0 R/W 0 This bit controls the clock gating for I2C module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 11:5 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 SSI0 R/W 0 This bit controls the clock gating for SSI module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 UART2 R/W 0 This bit controls the clock gating for UART module 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 1 UART1 R/W 0 This bit controls the clock gating for UART module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 0 UART0 R/W 0 This bit controls the clock gating for UART module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 98 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 22: Sleep Mode Clock Gating Control Register 1 (SCGC1), offset 0x114 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC1 is the clock configuration register for running operation, SCGC1 for Sleep operation, and DCGC1 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. Sleep Mode Clock Gating Control Register 1 (SCGC1) Base 0x400F.E000 Offset 0x114 Type R/W, reset 0x00000000 31 30 29 28 27 reserved Type Reset RO 0 RO 0 RO 0 25 24 COMP1 COMP0 R/W 0 RO 0 RO 0 RO 0 8 7 6 5 RO 0 RO 0 R/W 0 R/W 0 11 10 9 15 14 13 12 reserved I2C1 reserved I2C0 RO 0 R/W 0 RO 0 R/W 0 Type Reset 26 COMP2 23 22 21 reserved RO 0 RO 0 RO 0 RO 0 20 reserved RO 0 RO 0 RO 0 RO 0 19 18 17 16 TIMER3 TIMER2 TIMER1 TIMER0 R/W 0 R/W 0 R/W 0 R/W 0 4 3 2 1 0 SSI0 reserved UART2 UART1 UART0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:27 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 26 COMP2 R/W 0 This bit controls the clock gating for analog comparator 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 25 COMP1 R/W 0 This bit controls the clock gating for analog comparator 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 24 COMP0 R/W 0 This bit controls the clock gating for analog comparator 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 23:20 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 19 TIMER3 R/W 0 This bit controls the clock gating for General-Purpose Timer module 3. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. June 14, 2007 99 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset Description 18 TIMER2 R/W 0 This bit controls the clock gating for General-Purpose Timer module 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 17 TIMER1 R/W 0 This bit controls the clock gating for General-Purpose Timer module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 16 TIMER0 R/W 0 This bit controls the clock gating for General-Purpose Timer module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14 I2C1 R/W 0 This bit controls the clock gating for I2C module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 I2C0 R/W 0 This bit controls the clock gating for I2C module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 11:5 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 SSI0 R/W 0 This bit controls the clock gating for SSI module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 UART2 R/W 0 This bit controls the clock gating for UART module 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 1 UART1 R/W 0 This bit controls the clock gating for UART module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 0 UART0 R/W 0 This bit controls the clock gating for UART module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 100 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 23: Deep Sleep Mode Clock Gating Control Register 1 (DCGC1), offset 0x124 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC1 is the clock configuration register for running operation, SCGC1 for Sleep operation, and DCGC1 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. Deep Sleep Mode Clock Gating Control Register 1 (DCGC1) Base 0x400F.E000 Offset 0x124 Type R/W, reset 0x00000000 31 30 29 28 27 reserved Type Reset RO 0 RO 0 RO 0 25 24 COMP1 COMP0 R/W 0 RO 0 RO 0 RO 0 8 7 6 5 RO 0 RO 0 R/W 0 R/W 0 11 10 9 15 14 13 12 reserved I2C1 reserved I2C0 RO 0 R/W 0 RO 0 R/W 0 Type Reset 26 COMP2 23 22 21 reserved RO 0 RO 0 RO 0 RO 0 20 reserved RO 0 RO 0 RO 0 RO 0 19 18 17 16 TIMER3 TIMER2 TIMER1 TIMER0 R/W 0 R/W 0 R/W 0 R/W 0 4 3 2 1 0 SSI0 reserved UART2 UART1 UART0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:27 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 26 COMP2 R/W 0 This bit controls the clock gating for analog comparator 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 25 COMP1 R/W 0 This bit controls the clock gating for analog comparator 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 24 COMP0 R/W 0 This bit controls the clock gating for analog comparator 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 23:20 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 19 TIMER3 R/W 0 This bit controls the clock gating for General-Purpose Timer module 3. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. June 14, 2007 101 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset Description 18 TIMER2 R/W 0 This bit controls the clock gating for General-Purpose Timer module 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 17 TIMER1 R/W 0 This bit controls the clock gating for General-Purpose Timer module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 16 TIMER0 R/W 0 This bit controls the clock gating for General-Purpose Timer module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14 I2C1 R/W 0 This bit controls the clock gating for I2C module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 I2C0 R/W 0 This bit controls the clock gating for I2C module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 11:5 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 SSI0 R/W 0 This bit controls the clock gating for SSI module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 UART2 R/W 0 This bit controls the clock gating for UART module 2. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 1 UART1 R/W 0 This bit controls the clock gating for UART module 1. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 0 UART0 R/W 0 This bit controls the clock gating for UART module 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 102 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 24: Run Mode Clock Gating Control Register 2 (RCGC2), offset 0x108 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC2 is the clock configuration register for running operation, SCGC2 for Sleep operation, and DCGC2 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. Run Mode Clock Gating Control Register 2 (RCGC2) Base 0x400F.E000 Offset 0x108 Type R/W, reset 0x00000000 31 30 29 28 reserved EPHY0 reserved EMAC0 RO 0 R/W 0 RO 0 15 14 RO 0 RO 0 Type Reset 27 26 25 24 23 22 R/W 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 13 12 11 10 9 8 7 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 GPIOG GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved reserved Type Reset 21 RO 0 Bit/Field Name Type Reset Description 31 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 30 EPHY0 R/W 0 This bit controls the clock gating for Ethernet PHY unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 29 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 28 EMAC0 R/W 0 This bit controls the clock gating for Ethernet MAC unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 27:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 GPIOG R/W 0 This bit controls the clock gating for Port G. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 5 GPIOF R/W 0 This bit controls the clock gating for Port F. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. June 14, 2007 103 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset Description 4 GPIOE R/W 0 This bit controls the clock gating for Port E. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 3 GPIOD R/W 0 This bit controls the clock gating for Port D. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 2 GPIOC R/W 0 This bit controls the clock gating for Port C. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 1 GPIOB R/W 0 This bit controls the clock gating for Port B. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 0 GPIOA R/W 0 This bit controls the clock gating for Port A. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 104 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 25: Sleep Mode Clock Gating Control Register 2 (SCGC2), offset 0x118 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC2 is the clock configuration register for running operation, SCGC2 for Sleep operation, and DCGC2 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. Sleep Mode Clock Gating Control Register 2 (SCGC2) Base 0x400F.E000 Offset 0x118 Type R/W, reset 0x00000000 31 30 29 28 reserved EPHY0 reserved EMAC0 RO 0 R/W 0 RO 0 R/W 0 15 14 13 12 Type Reset 27 26 25 24 23 RO 0 RO 0 RO 0 RO 0 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 reserved RO 0 RO 0 RO 0 RO 0 RO 0 11 10 9 8 7 reserved Type Reset 22 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 6 5 4 3 2 1 0 GPIOG GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 30 EPHY0 R/W 0 This bit controls the clock gating for Ethernet PHY unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 29 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 28 EMAC0 R/W 0 This bit controls the clock gating for Ethernet MAC unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 27:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 GPIOG R/W 0 This bit controls the clock gating for Port G. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. June 14, 2007 105 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset Description 5 GPIOF R/W 0 This bit controls the clock gating for Port F. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 4 GPIOE R/W 0 This bit controls the clock gating for Port E. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 3 GPIOD R/W 0 This bit controls the clock gating for Port D. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 2 GPIOC R/W 0 This bit controls the clock gating for Port C. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 1 GPIOB R/W 0 This bit controls the clock gating for Port B. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 0 GPIOA R/W 0 This bit controls the clock gating for Port A. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 106 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 26: Deep Sleep Mode Clock Gating Control Register 2 (DCGC2), offset 0x128 This register controls the clock gating logic. Each bit controls a clock enable for a given interface, function, or unit. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled (saving power). If the unit is unclocked, reads or writes to the unit will generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise noted, so that all functional units are disabled. It is the responsibility of software to enable the ports necessary for the application. Note that these registers may contain more bits than there are interfaces, functions, or units to control. This is to assure reasonable code compatibility with other family and future parts. RCGC2 is the clock configuration register for running operation, SCGC2 for Sleep operation, and DCGC2 for Deep-Sleep operation. Setting the ACG bit in the Run-Mode Clock Configuration (RCC) register specifies that the system uses sleep modes. Deep Sleep Mode Clock Gating Control Register 2 (DCGC2) Base 0x400F.E000 Offset 0x128 Type R/W, reset 0x00000000 31 30 29 28 reserved EPHY0 reserved EMAC0 RO 0 R/W 0 RO 0 R/W 0 15 14 13 12 Type Reset 27 26 25 24 23 RO 0 RO 0 RO 0 RO 0 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 reserved RO 0 RO 0 RO 0 RO 0 RO 0 11 10 9 8 7 reserved Type Reset 22 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 6 5 4 3 2 1 0 GPIOG GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 30 EPHY0 R/W 0 This bit controls the clock gating for Ethernet PHY unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 29 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 28 EMAC0 R/W 0 This bit controls the clock gating for Ethernet MAC unit 0. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 27:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 GPIOG R/W 0 This bit controls the clock gating for Port G. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. June 14, 2007 107 Luminary Micro Confidential-Advance Product Information System Control Bit/Field Name Type Reset Description 5 GPIOF R/W 0 This bit controls the clock gating for Port F. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 4 GPIOE R/W 0 This bit controls the clock gating for Port E. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 3 GPIOD R/W 0 This bit controls the clock gating for Port D. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 2 GPIOC R/W 0 This bit controls the clock gating for Port C. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 1 GPIOB R/W 0 This bit controls the clock gating for Port B. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 0 GPIOA R/W 0 This bit controls the clock gating for Port A. If set, the unit receives a clock and functions. Otherwise, the unit is unclocked and disabled. If the unit is unclocked, reads or writes to the unit will generate a bus fault. 108 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 27: Software Reset Control 0 (SRCR0), offset 0x040 Writes to this register are masked by the bits in the Device Capabilities 1 (DC1) register. Software Reset Control 0 (SRCR0) Base 0x400F.E000 Offset 0x040 Type R/W, reset 0x00000000 31 30 29 RO 0 RO 0 RO 0 15 14 RO 0 RO 0 28 27 26 25 23 22 21 RO 0 RO 0 RO 0 RO 0 R/W 0 RO 0 RO 0 RO 0 13 12 11 10 9 8 7 6 5 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 reserved Type Reset 24 CAN0 RO 0 19 18 17 RO 0 RO 0 RO 0 RO 0 R/W 0 4 3 2 1 0 reserved reserved Type Reset 20 HIB reserved RO 0 RO 0 16 SARADC0 WDT R/W 0 reserved RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:25 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 24 CAN0 R/W 0 Reset control for CAN unit 0. 23:17 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 16 SARADC0 R/W 0 Reset control for SAR ADC module 0. 15:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 HIB R/W 0 Reset control for the Hibernation module. 5:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 WDT R/W 0 Reset control for Watchdog unit. 2:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 109 Luminary Micro Confidential-Advance Product Information System Control Register 28: Software Reset Control 1 (SRCR1), offset 0x044 Writes to this register are masked by the bits in the Device Capabilities 2 (DC2) register. Software Reset Control 1 (SRCR1) Base 0x400F.E000 Offset 0x044 Type R/W, reset 0x00000000 31 30 RO 0 RO 0 15 29 28 27 26 25 24 RO 0 RO 0 RO 0 COMP2 COMP1 COMP0 R/W 0 R/W 0 14 13 12 11 10 9 reserved I2C1 reserved I2C0 RO 0 R/W 0 RO 0 R/W 0 RO 0 RO 0 RO 0 reserved Type Reset Type Reset 23 22 21 R/W 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 19 18 17 16 TIMER3 TIMER2 TIMER1 TIMER0 R/W 0 R/W 0 R/W 0 R/W 0 4 3 2 1 0 RO 0 RO 0 RO 0 SSI0 reserved UART2 UART1 UART0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 reserved reserved RO 0 20 Bit/Field Name Type Reset Description 31:27 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 26 COMP2 R/W 0 Reset control for analog comparator 2. 25 COMP1 R/W 0 Reset control for analog comparator 1. 24 COMP0 R/W 0 Reset control for analog comparator 0. 23:20 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 19 TIMER3 R/W 0 Reset control for General-Purpose Timer module 3. 18 TIMER2 R/W 0 Reset control for General-Purpose Timer module 2. 17 TIMER1 R/W 0 Reset control for General-Purpose Timer module 1. 16 TIMER0 R/W 0 Reset control for General-Purpose Timer module 0. 15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14 I2C1 R/W 0 Reset control for I2C unit 1. 13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 I2C0 R/W 0 Reset control for I2C unit 0. 11:5 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 SSI0 R/W 0 Reset control for SSI unit 0. 110 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset Description 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 UART2 R/W 0 Reset control for UART unit 2. 1 UART1 R/W 0 Reset control for UART unit 1. 0 UART0 R/W 0 Reset control for UART unit 0. June 14, 2007 111 Luminary Micro Confidential-Advance Product Information System Control Register 29: Software Reset Control 2 (SRCR2), offset 0x048 Writes to this register are masked by the bits in the Device Capabilities 4 (DC4) register. Software Reset Control 2 (SRCR2) Base 0x400F.E000 Offset 0x048 Type R/W, reset 0x00000000 31 30 29 28 reserved EPHY0 reserved EMAC0 RO 0 R/W 0 RO 0 15 14 RO 0 RO 0 Type Reset 27 26 25 24 23 22 R/W 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 13 12 11 10 9 8 7 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 GPIOG GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved reserved Type Reset 21 RO 0 Bit/Field Name Type Reset Description 31 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 30 EPHY0 R/W 0 Reset control for Ethernet PHY unit 0. 29 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 28 EMAC0 R/W 0 Reset control for Ethernet MAC unit 0. 27:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 GPIOG R/W 0 Reset control for GPIO Port G. 5 GPIOF R/W 0 Reset control for GPIO Port F. 4 GPIOE R/W 0 Reset control for GPIO Port E. 3 GPIOD R/W 0 Reset control for GPIO Port D. 2 GPIOC R/W 0 Reset control for GPIO Port C. 1 GPIOB R/W 0 Reset control for GPIO Port B. 0 GPIOA R/W 0 Reset control for GPIO Port A. 112 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 7 Hibernation Module HIB The Hibernation Module manages removal and restoration of power to the rest of the microcontroller to provide a means for reducing power consumption. When the processor and peripherals are idle, power can be completely removed with only the Hibernation Module remaining powered. Power can be restored based on an external signal, or at a certain time using the built-in real-time clock (RTC). The Hibernation module can be independently supplied from a battery or an auxillary power supply. The Hibernation module has the following features: ■ Power-switching logic to discrete external regulator ■ Dedicated pin for waking from an external signal ■ Low-battery detection, signalling, and interrupt generation ■ 32-bit real-time counter (RTC) ■ Two 32-bit RTC match registers for timed wake-up and interrupt generation ■ Clock source from a 32.768-kHz external oscillator or a 4.194304-MHz crystal ■ RTC trim predivider for making fine adjustments to the clock rate ■ 64 32-bit words of non-volatile memory ■ Programmable interrupts for RTC match, external wake, and low battery events June 14, 2007 113 Luminary Micro Confidential-Advance Product Information Hibernation Module 7.1 Block Diagram Figure 7-1. Hibernation Module Block Diagram HIBCTL.CLK32EN XOSC0 XOSC1 Interrupts HIBIM HIBRIS HIBMIS HIBIC Pre-Divider /128 HIBRTCT HIBCTL.CLKSEL Non-Volatile Memory HIBDATA RTC HIBRTCC HIBRTCLD HIBRTCM0 HIBRTCM1 WAKE MATCH0/1 LOWBAT VDD Low Battery Detect VBAT HIBCTL.LOWBATEN 7.2 Interrupts to CPU Power Sequence Logic HIB HIBCTL.PWRCUT HIBCTL.RTCWEN HIBCTL.EXTWEN HIBCTL.VABORT Functional Description The Hibernation module controls the power to the processor with an enable signal (HIB) that signals an external voltage regulator to turn off. The Hibernation module itself is powered from a separate supply such as a battery or auxillary supply. It also has a separate clock source to maintain a real-time clock (RTC). Once in hibernation, the module signals an external voltage regulator to turn back on the power when an external pin (WAKE) is asserted, or when the internal RTC reaches a certain value. The Hibernation module can also detect when the battery voltage is low, and optionally prevent hibernation when this occurs. Power-up from a power cut to code execution is defined as the regulator turn-on time (specifed at 250 μs maximum) plus the normal chip POR (see Figure 22-12 on page 524). 7.2.1 Register Access Timing Because the Hibernation module has an independent clocking domain, certain registers must be written only with a timing gap between accesses. The delay time is tHIB_REG_WRITE, therefore software must guarantee that a delay of tHIB_REG_WRITE is inserted between back-to-back writes to certain Hibernation registers, or between a write followed by a read to those same registers. There is no restriction on timing for back-to-back reads from the Hibernation module. Refer to “Register Descriptions” on page 118 for details about which registers are subject to this timing restriction. 114 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 7.2.2 Clock Source The Hibernation module must be clocked by an external source, even if the RTC feature will not be used. An external oscillator or crystal can be used for this purpose. To use a crystal, a 4.194304-MHz crystal is connected to the XOSC0 and XOSC1 pins. This clock signal will be divided by 128 internally to produce the 32.768-kHz clock reference. To use a more precise clock source, a 32.768-kHz oscillator can be connected to the XOSC0 pin. The clock source is enabled by setting the CLK32EN bit of the HIBCTL register. The type of clock source is selected by setting the CLKSEL bit to 0 for a 4.194304-MHz clock source, and to 1 for a 32.768-kHz clock source. If the bit is set to 0, the input clock is divided by 128, resulting in a 32.768-kHz clock source. If a crystal is used for the clock source, the software must leave a delay of tXOSC_SETTLE after setting the CLK32EN bit and before any other accesses to the Hibernation module registers. The delay allows the crystal to power up and stabilize. If an oscillator is used for the clock source, no delay is needed. 7.2.3 Battery Management The Hibernation module can be independently powered by a battery or an auxiliary power source. The module can monitor the voltage level of the battery and detect when the voltage becomes too low. When this happens, an interrupt can be generated. The module can also be configured so that it will not go into Hibernate mode if the battery voltage is too low. Note that the Hibernation module draws power from whichever source (VBAT or VDD) has the higher voltage. Therefore, it is important to design the circuit to ensure that VDD is higher that VBAT under nominal conditions or else the Hibernation module draws power from the battery even when VDD is available. The Hibernation module can be configured to detect a low battery condition by setting the LOWBATEN bit of the HIBCTL register. In this configuration, the LOWBAT bit of the HIBRIS register will be set when the battery level is low. If the VABORT bit is also set, then the module is prevented from entering Hibernation mode when a low battery is detected. The module can also be configured to generate an interrupt for the low-battery condition (see “Interrupts and Status” on page 116). 7.2.4 Real-Time Clock The Hibernation module includes a 32-bit counter that increments once per second with a proper clock source and configuration (see “Clock Source” on page 115). The 32.768-kHz clock signal is fed into a trim predivider which counts down from a nominal value of 0x7FFF to achieve a once per second clock rate for the RTC. The trim predivider register can be adjusted up or down to compensate for inaccuracies in the clock source. The trim predivider should be adjusted up from 0x7FFF in order to slow down the RTC rate, and down from 0x7FFF in order to speed up the RTC rate. The Hibernation module includes two 32-bit match registers that are compared to the value of the RTC counter. The match registers can be used to wake the processor from hibernation mode, or to generate an interrupt to the processor if it is not in hibernation. The RTC must be enabled with the RTCEN bit of the HIBCTL register. The value of the RTC can be set at any time by writing to the HIBRTCLD register. The trim predivider can be adjusted by reading and writing the HIBRTCT register. The predivider is updated once every 64 seconds from this register. The two match registers can be set by writing to the HIBRTCM0 and HIBRTCM1 registers. The RTC can be configured to generate interrupts by using the interrupt registers (see “Interrupts and Status” on page 116). June 14, 2007 115 Luminary Micro Confidential-Advance Product Information Hibernation Module 7.2.5 Non-Volatile Memory The Hibernation module contains 64 32-bit words of memory which are retained during hibernation. This memory is powered from the battery or auxillary power supply during hibernation. The processor software can save state information in this memory prior to hibernation, and can then recover the state upon waking. The non-volatile memory can be accessed through the HIBDATA registers. 7.2.6 Power Control The Hibernation module controls power to the processor through the use of the HIB pin, which is intended to be connected to the enable signal of the external regulator(s) providing 3.3 V and/or 2.5 V to the microcontroller. When the HIB signal is asserted by the Hibernation module, the external regulator is turned off and no longer powers the microcontroller. The Hibernation module remains powered from the VBAT supply, which could be a battery or an auxillary power source. Hibernation mode is initiated by the microcontroller setting the HIBREQ bit of the HIBCTL register. Prior to doing this, a wake-up condition must be configured, either from the external WAKE pin, or by using an RTC match. The Hibernation module is configured to wake from the external WAKE pin by setting the PINWEN bit of the HIBCTL register. It is configured to wake from RTC match by setting the RTCWEN bit. Either one or both of these bits can be set prior to going into hibernation. When the Hibernation module wakes, the microcontroller will see a normal power-on reset. It can detect that the power-on was due to a wake from hibernation by examining the raw interrupt status register (see “Interrupts and Status” on page 116) and by looking for state data in the non-volatile memory (see “Non-Volatile Memory” on page 116). 7.2.7 Interrupts and Status The Hibernation module can generate interrupts when the following conditions occur: ■ Assertion of WAKE pin ■ RTC match ■ Low battery detected All of the interrupts are ORed together before being sent to the interrupt controller, so the Hibernate module can only generate a single interrupt request to the controller at any given time. The software interrupt handler can service multiple interrupt events by reading the HIBMIS register. Software can also read the status of the Hibernation module at any time by reading the HIBRIS register which shows all of the pending events. This register can be used at power-on to see if a wake condition is pending, which indicates to the software that a hibernation wake occurred. The events that can trigger an interrupt are configured by setting the appropriate bits in the HIBIM register. Pending interrupts can be cleared by writing the corresponding bit in the HIBIC register. 7.3 Initialization and Configuration The Hibernation module can be configured in several different combinations. The following sections show the recommended programming sequence for various scenarios. The examples below assume that a 32.768-kHz oscillator is used, and thus always show bit 2 (CLKSEL) of the HIBCTL register set to 1. If a 4.194304-MHz crystal is used instead, then the CLKSEL bit remains cleared. Because the Hibernation module runs at 32 kHz and is asynchronous to the rest of the system, software must allow a delay of tHIB_REG_WRITE after writes to certain registers (see “Register Access 116 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Timing” on page 114). The registers that require a delay are denoted with a footnote in Table 7-1 on page 118. 7.3.1 Initialization The clock source must be enabled first, even if the RTC will not be used. If a 4.194304-MHz crystal is used, perform the following steps: 1. Write 0x40 to the HIBCTL register at offset 0x10 to enable the crystal and select the divide-by-128 input path. 2. Wait for a time of tXOSC_SETTLE for the crystal to power up and stabilize before performing any other operations with the Hibernation module. If a 32.678-kHz oscillator is used, then perform the following steps: 1. Write 0x44 to the HIBCTL register at offset 0x10 to enable the oscillator input. 2. No delay is necessary. The above is only necessary when the entire system is initialized for the first time. If the processor is powered due to a wake from hibernation, then the Hibernation module has already been powered up and the above steps are not necessary. The software can detect that the Hibernation module and clock are already powered by examining the CLK32EN bit of the HIBCTL register. 7.3.2 RTC Match Functionality (No Hibernation) The following steps are needed to use the RTC match functionality of the Hibernation module: 1. Write the required RTC match value to one of the HIBRTCMn registers at offset 0x004 or 0x008. 2. Write the required RTC load value to the HIBRTCLD register at offset 0x00C. 3. Set the required RTC match interrupt mask in the RTCALT0 and RTCALT1 bits (bits 1:0) in the HIBIM register at offset 0x014. 4. Write 0x0000.0041 to the HIBCTL register at offset 0x010 to enable the RTC to begin counting. 7.3.3 RTC Match/Wake-Up from Hibernation The following steps are needed to use the RTC match and wake-up functionality of the Hibernation module: 1. Write the required RTC match value to the RTCMn registers at offset 0x004 or 0x008. 2. Write the required RTC load value to the HIBRTCLD register at offset 0x00C. 3. Write any data to be retained during power cut to the HIBDATA register at offsets 0x030-0x130. 4. Set the RTC Match Wake-Up and start the hibernation sequence by writing 0x0000.004F to the HIBCTL register at offset 0x010. 7.3.4 External Wake-Up from Hibernation The following steps are needed to use the Hibernation module with the external WAKE pin as the wake-up source for the microcontroller: June 14, 2007 117 Luminary Micro Confidential-Advance Product Information Hibernation Module 1. Write any data to be retained during power cut to the HIBDATA register at offsets 0x030-0x130. 2. Enable the external wake and start the hibernation sequence by writing 0x0000.0056 to the HIBCTL register at offset 0x010. 7.3.5 RTC/External Wake-Up from Hibernation 1. Write the required RTC match value to the RTCMn registers at offset 0x004 or 0x008. 2. Write the required RTC load value to the HIBRTCLD register at offset 0x00C. 3. Write any data to be retained during power cut to the HIBDATA register at offsets 0x030-0x130. 4. Set the RTC Match/External Wake-Up and start the hibernation sequence by writing 0x0000.005F to the HIBCTL register at offset 0x010. 7.4 Register Map Note: HIBRTCC, HIBRTCM0, HIBRTCM1, HIBRTCLD, HIBRTCT, and HIBDATA are internal BAPI module registers on the VBAPI voltage domain and the 32-kHz clock domain. Table 7-1. Hibernation Module Register Map Offset Name 0x000 See page Type Reset HIBRTCC RO 0x0000.0000 Hibernation RTC Counter 119 0x004 HIBRTCM0 R/W 0xFFFF.FFFF Hibernation RTC Match 0 120 0x008 HIBRTCM1 R/W 0xFFFF.FFFF Hibernation RTC Match 1 121 0x00C HIBRTCLD R/W 0xFFFF.FFFF Hibernation RTC Load 122 0x010 HIBCTL R/W 0x0000.0000 Hibernation Control 123 0x014 HIBIM R/W 0x0000.0000 Hibernation Interrupt Mask 125 0x018 HIBRIS RO 0x0000.0000 Hibernation Raw Interrupt Status 126 0x01C HIBMIS RO 0x0000.0000 Hibernation Masked Interrupt Status 127 0x020 HIBIC W1C 0x0000.0000 Hibernation Interrupt Clear 128 0x024 HIBRTCT R/W 0x0000.0000 Hibernation RTC Trim 129 0x0300x12C HIBDATA R/W 0x0000.0000 Hibernation Data 130 7.5 Description Register Descriptions All addresses given are relative to the Hibernation module Base Address at 0x400F.C000. 118 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 1: Hibernation RTC Counter (HIBRTCC), offset 0x000 This register is the current 32-bit value of the RTC counter. Hibernation RTC Counter (HIBRTCC) Offset 0x000 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RTCC Type Reset RTCC Type Reset Bit/Field Name Type 31:0 RTCC RO Reset Description 0x0000.0000 RTC Counter A read returns the 32-bit counter value. This register is read-only. To change the value, use the HIBRTCLD register. June 14, 2007 119 Luminary Micro Confidential-Advance Product Information Hibernation Module Register 2: Hibernation RTC Match 0 (HIBRTCM0), offset 0x004 This register is the 32-bit match 0 register for the RTC counter. Hibernation RTC Match 0 (HIBRTCM0) Offset 0x004 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 RTCM0 Type Reset RTCM0 Type Reset Bit/Field Name Type 31:0 RTCM0 R/W Reset Description 0xFFFF.FFFF RTC Match 0 A write loads the value into the RTC match register. A read returns the current match value. 120 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 3: Hibernation RTC Match 1 (HIBRTCM1), offset 0x008 This register is the 32-bit match 1 register for the RTC counter. Hibernation RTC Match 1 (HIBRTCM1) Offset 0x008 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 RTCM1 Type Reset RTCM1 Type Reset Bit/Field Name Type 31:0 RTCM1 R/W Reset Description 0xFFFF.FFFF RTC Match 1 A write loads the value into the RTC match register. A read returns the current match value. June 14, 2007 121 Luminary Micro Confidential-Advance Product Information Hibernation Module Register 4: Hibernation RTC Load (HIBRTCLD), offset 0x00C This register is the 32-bit value loaded into the RTC counter. Hibernation RTC Load (HIBRTCLD) Offset 0x00C Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 RTCLD Type Reset RTCLD Type Reset Bit/Field Name Type 31:0 RTCLD R/W Reset Description 0xFFFF.FFFF RTC Load A writes load the current value into the RTC counter (RTCC). A read returns the 32-bit load value. 122 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 5: Hibernation Control (HIBCTL), offset 0x010 This register is the control register for the Hibernation module. Hibernation Control (HIBCTL) Offset 0x010 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 reserved Type Reset reserved Type Reset VABORT CLK32EN LOWBATEN PINWEN RTCWEN CLKSEL HIBREQ RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 RTCEN R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0x00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7 VABORT R/W 0 Power Cut Abort Enable 0: Power Cut occurs during a low-battery alert 1: Power Cut is aborted 6 CLK32EN R/W 0 32-kHz Oscillator Enable 0: Disabled 1: Enabled This bit must be enabled to use the Hibernation module. If a crystal is used, then software should wait 20 ms after setting this bit to allow the crystal to power up and stabilize. 5 LOWBATEN R/W 0 LOW BAT Monitoring Enable 0: Disabled 1: Enabled When set, low battery voltage detection is enabled. 4 PINWEN R/W 0 External WAKE Pin Enable 0: Disabled 1: Enabled When set, an external event on the WAKE pin will re-power the device. 3 RTCWEN R/W 0 RTC Wake-up Enable 0: Disabled 1: Enabled When set, an RTC match event (RTC0 or RTC1) will re-power the device based on the RTC counter value matching the corresponding match register 0 or 1. June 14, 2007 123 Luminary Micro Confidential-Advance Product Information Hibernation Module Bit/Field Name Type Reset 2 CLKSEL R/W 0 Description Hibernation Module Clock Select 0: Use Divide by 128 output. Use this value for a 4-MHz crystal. 1: Use raw output. Use this value for a 32-kHz oscillator. 1 HIBREQ R/W 0 Hibernation Request 0: Disabled 1: Hibernation initiated After a wake-up event, this bit is cleared by hardware. 0 RTCEN R/W 0 RTC Timer Enable 0: Disabled 1: Enabled 124 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: Hibernation Interrupt Mask (HIBIM), offset 0x014 This register is the interrupt mask register for the Hibernation module interrupt sources. Hibernation Interrupt Mask (HIBIM) Offset 0x014 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:4 reserved RO 0x000.0000 3 EXTW R/W 0 EXTW R/W 0 LOWBAT RTCALT1 RTCALT0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. External Wake-Up Interrupt Mask 0: Masked 1: Unmasked 2 LOWBAT R/W 0 Low Battery Voltage Interrupt Mask 0: Masked 1: Unmasked 1 RTCALT1 R/W 0 RTC Alert1 Interrupt Mask 0: Masked 1: Unmasked 0 RTCALT0 R/W 0 RTC Alert0 Interrupt Mask 0: Masked 1: Unmasked June 14, 2007 125 Luminary Micro Confidential-Advance Product Information Hibernation Module Register 7: Hibernation Raw Interrupt Status (HIBRIS), offset 0x018 This register is the raw interrupt status for the Hibernation module interrupt sources. Hibernation Raw Interrupt Status (HIBRIS) Offset 0x018 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset EXTW RO 0 Bit/Field Name Type Reset 31:4 reserved RO 0x000.0000 3 EXTW RO 0 External Wake-Up Raw Interrupt Status 2 LOWBAT RO 0 Low Battery Voltage Raw Interrupt Status 1 RTCALT1 RO 0 RTC Alert1 Raw Interrupt Status 0 RTCALT0 RO 0 RTC Alert0 Raw Interrupt Status LOWBAT RTCALT1 RTCALT0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 126 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 8: Hibernation Masked Interrupt Status (HIBMIS), offset 0x01C This register is the masked interrupt status for the Hibernation module interrupt sources. Hibernation Masked Interrupt Status (HIBMIS) Offset 0x01C Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset EXTW RO 0 Bit/Field Name Type Reset 31:4 reserved RO 0x000.0000 3 EXTW RO 0 External Wake-Up Masked Interrupt Status 2 LOWBAT RO 0 Low Battery Voltage Masked Interrupt Status 1 RTCALT1 RO 0 RTC Alert1 Masked Interrupt Status 0 RTCALT0 RO 0 RTC Alert0 Masked Interrupt Status LOWBAT RTCALT1 RTCALT0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 127 Luminary Micro Confidential-Advance Product Information Hibernation Module Register 9: Hibernation Interrupt Clear (HIBIC), offset 0x020 This register is the interrupt write-one-to-clear register for the Hibernation module interrupt sources. Hibernation Interrupt Clear (HIBIC) Offset 0x020 Type W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W1C 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:4 reserved RO 0x000.0000 3 EXTW R/W1C 0 EXTW LOWBAT RTCALT1 RTCALT0 R/W1C 0 R/W1C 0 R/W1C 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. External Wake-Up Masked Interrupt Clear Reads return an indeterminate value. 2 LOWBAT R/W1C 0 Low Battery Voltage Masked Interrupt Clear Reads return an indeterminate value. 1 RTCALT1 R/W1C 0 RTC Alert1 Masked Interrupt Clear Reads return an indeterminate value. 0 RTCALT0 R/W1C 0 RTC Alert0 Masked Interrupt Clear Reads, return an indeterminate value. 128 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 10: Hibernation RTC Trim (HIBRTCT), offset 0x024 This register contains the value that is used to trim the RTC clock predivider. It represents the computed underflow value that is used during the trim cycle. It is represented as 0x7FFF ± N clock cycles. Hibernation RTC Trim (HIBRTCT) Offset 0x024 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 reserved Type Reset TRIM Type Reset Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 TRIM R/W 0x7FFF RTC Trim Value This value is loaded into the RTC predivider every 64 seconds. It is used to adjust the RTC rate to account for drift and inaccuracy in the clock source. The compensation is made by software by adjusting the default value of 0x7FFF up or down. June 14, 2007 129 Luminary Micro Confidential-Advance Product Information Hibernation Module Register 11: Hibernation Data (HIBDATA), offset 0x030-0x12C This address space is implemented as a 64x32-bit memory (256 bytes). It can be loaded by the system processor in order to store any non-volatile state data and will not lose power during a power cut operation. Hibernation Data (HIBDATA) Offset 0x030-0x12C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 RTD Type Reset RTD Type Reset Bit/Field Name Type 31:0 RTD R/W Reset Description 0x0000.0000 Hibernation Module NV Registers[63:0] 130 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 8 Internal Memory FLASH The LM3S8938 microcontroller comes with 64 KB of bit-banded SRAM and 256 KB of flash memory. The flash controller provides a user-friendly interface, making flash programming a simple task. Flash protection can be applied to the flash memory on a 2-KB block basis. 8.1 Block Diagram Figure 8-1. Flash Block Diagram Flash Timing USECRL Flash Control ICode Cortex-M3 DCode FMA Flash Array FMD FMC System Bus FCRIS FCIM FCMISC APB Bridge Flash Protection User Registers USER_DBG SRAM Array 8.2 FMPREn USER_REG0 FMPPEn USER_REG1 Functional Description This section describes the functionality of both the flash and SRAM memories. 8.2.1 SRAM Memory ® The internal SRAM of the Stellaris devices is located at address 0x2000.0000 of the device memory map. To reduce the number of time consuming read-modify-write (RMW) operations, ARM has introduced bit-banding technology in the Cortex-M3 processor. With a bit-band-enabled processor, certain regions in the memory map (SRAM and peripheral space) can use address aliases to access individual bits in a single, atomic operation. June 14, 2007 131 Luminary Micro Confidential-Advance Product Information Internal Memory The bit-band alias is calculated by using the formula: bit-band alias = bit-band base + (byte offset * 32) + (bit number * 4) For example, if bit 3 at address 0x2000.1000 is to be modified, the bit-band alias is calculated as: 0x2200.0000 + (0x1000 * 32) + (3 * 4) = 0x2202.000C With the alias address calculated, an instruction performing a read/write to address 0x2202.000C allows direct access to only bit 3 of the byte at address 0x2000.1000. For details about bit-banding, please refer to Chapter 4, “Memory Map” in the ARM® Cortex™-M3 Technical Reference Manual. 8.2.2 Flash Memory The flash is organized as a set of 1-KB blocks that can be individually erased. Erasing a block causes the entire contents of the block to be reset to all 1s. An individual 32-bit word can be programmed to change bits that are currently 1 to a 0. These blocks are paired into a set of 2-KB blocks that can be individually protected. The protection allows blocks to be marked as read-only or execute-only, providing different levels of code protection. Read-only blocks cannot be erased or programmed, protecting the contents of those blocks from being modified. Execute-only blocks cannot be erased or programmed, and can only be read by the controller instruction fetch mechanism, protecting the contents of those blocks from being read by either the controller or by a debugger. 8.2.2.1 Flash Memory Timing The timing for the flash is automatically handled by the flash controller. However, in order to do so, it must know the clock rate of the system in order to time its internal signals properly. The number of clock cycles per microsecond must be provided to the flash controller for it to accomplish this timing. It is software's responsibility to keep the flash controller updated with this information via the USec Reload (USECRL) register. On reset, the USECRL register is loaded with a value that configures the flash timing so that it works with the maximum clock rate of the part. If software changes the system operating frequency, the new operating frequency minus 1 (in MHz) must be loaded into USECRL before any flash modifications are attempted. For example, if the device is operating at a speed of 20 MHz, a value of 0x13 (20-1) must be written to the USECRL register. 8.2.2.2 Flash Memory Protection The user is provided two forms of flash protection per 2-KB flash blocks infour pairs of 32-bit wide registers. The protection policy for each form is controlled by individual bits (per policy per block) in the FMPPEn and FMPREn registers. ■ Flash Memory Protection Program Enable (FMPPEn): If set, the block may be programmed (written) or erased. If cleared, the block may not be changed. ■ Flash Memory Protection Read Enable (FMPREn): If set, the block may be executed or read by software or debuggers. If cleared, the block may only be executed. The contents of the memory block are prohibited from being accessed as data and traversing the DCode bus. The policies may be combined as shown in Table 8-1 on page 133. 132 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Table 8-1. Flash Protection Policy Combinations FMPPEn FMPREn Protection 0 0 Execute-only protection. The block may only be executed and may not be written or erased. This mode is used to protect code. 1 0 The block may be written, erased or executed, but not read. This combination is unlikely to be used. 0 1 Read-only protection. The block may be read or executed but may not be written or erased. This mode is used to lock the block from further modification while allowing any read or execute access. 1 1 No protection. The block may be written, erased, executed or read. An access that attempts to program or erase a PE-protected block is prohibited. A controller interrupt may be optionally generated (by setting the AMASK bit in the FIM register) to alert software developers of poorly behaving software during the development and debug phases. An access that attempts to read an RE-protected block is prohibited. Such accesses return data filled with all 0s. A controller interrupt may be optionally generated to alert software developers of poorly behaving software during the development and debug phases. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This implements a policy of open access and programmability. The register bits may be changed by writing the specific register bit. The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. Details on programming these bits are discussed in “Nonvolatile Register Programming” on page 134. 8.3 Flash Memory Initialization and Configuration 8.3.1 Flash Programming ® The Stellaris devices provide a user-friendly interface for flash programming. All erase/program operations are handled via three registers: FMA, FMD, and FMC. 8.3.1.1 To program a 32-bit word: 1. Write source data to the FMD register. 2. Write the target address to the FMA register. 3. Write the flash write key and the WRITE bit (a value of 0xA442.0001) to the FMC register. 4. Poll the FMC register until the WRITE bit is cleared. 8.3.1.2 To perform an erase of a 1-KB page: 1. Write the page address to the FMA register. 2. Write the flash write key and the ERASE bit (a value of 0xA442.0002) to the FMC register. 3. Poll the FMC register until the ERASE bit is cleared. 8.3.1.3 To perform a mass erase of the flash: 1. Write the flash write key and the MERASE bit (a value of 0xA442.0004) to the FMC register. 2. Poll the FMC register until the MERASE bit is cleared. June 14, 2007 133 Luminary Micro Confidential-Advance Product Information Internal Memory 8.3.2 Nonvolatile Register Programming This section discusses how to update registers that are resident within the flash memory itself. These registers exist in a separate space from the main flash array and are not affected by an ERASE or MASS ERASE operation. These nonvolatile registers are updated by using the COMT bit in the FMC register to activate a write operation. For the USER_DBG register, the data to be written must be loaded into the FMD register before it is "committed". All other registers are R/W and can have their operation tried before committing them to nonvolatile memory. Important: These register can only have bits changed from 1 to 0 by the user and there is no mechanism for the user to erase them back to a 1 value. In addition, the USER_REG0, USER_REG1, and USER_DBG use bit 31 (NOTWRITTEN) of their respective registers to indicate that they are available for user write. These three registers can only be written once whereas the flash protection registers may be written multiple times. Table 8-2 on page 134 provides the FMA address required for commitment of each of the registers and the source of the data to be written when the COMT bit of the FMC register is written with a value of 0xA442.0008. After writing the COMT bit, the user may poll the FMC register to wait for the commit operation to complete. a Table 8-2. Flash Resident Registers Register to be Committed FMA Value Data Source FMPRE0 0x0000.0000 FMPRE0 FMPRE1 0x0000.0002 FMPRE1 FMPRE2 0x0000.0004 FMPRE2 FMPRE3 0x0000.0008 FMPRE3 FMPPE0 0x0000.0001 FMPPE0 FMPPE1 0x0000.0003 FMPPE1 FMPPE2 0x0000.0005 FMPPE2 FMPPE3 0x0000.0007 FMPPE3 USER_REG0 0x8000.0000 USER_REG0 USER_REG1 0x8000.0001 USER_REG1 USER_DBG 0x7510.0000 FMD ® a. Which FMPREn and FMPPEn registers are available depend on the flash size of your particular Stellaris device. 8.4 Register Map Table 8-3 on page 134 lists the Flash memory and control registers. The offset listed is a hexadecimal increment to the register's address. The FMA, FMD, FMC, FCRIS, FCIM, and FCMISC registers are relative to the Flash control base address of 0x400F.D000. The FMPREn, FMPPEn, USECRL, USER_DBG, and USER_REGn registers are relative to the System Control base address of 0x400F.E000. Note: A BV in the Reset column indicates the reset is a Build Value and part-specific. See the page number referenced for the reset value description. Table 8-3. Internal Memory Register Map Offset Name Type Reset Description See page Flash Control Offset 134 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Description See page Offset Name Type Reset 0x000 FMA R/W 0x0000.0000 Flash Memory Address 136 0x004 FMD R/W 0x0000.0000 Flash Memory Data 137 0x008 FMC R/W 0x0000.0000 Flash Memory Control 138 0x00C FCRIS RO 0x0000.0000 Flash Controller Raw Interrupt Status 140 0x010 FCIM R/W 0x0000.0000 Flash Controller Interrupt Mask 141 0x014 FCMISC R/W1C 0x0000.0000 Flash Controller Masked Interrupt Status and Clear 142 System Control Offset 0x130 FMPRE0 R/W BV Flash Memory Protection Read Enable 0 144 0x200 FMPRE0 R/W BV Flash Memory Protection Read Enable 0 144 0x134 FMPPE0 R/W BV Flash Memory Protection Program Enable 0 145 0x400 FMPPE0 R/W BV Flash Memory Protection Program Enable 0 145 0x140 USECRL R/W 0x31 USec Reload 143 0x1D0 USER_DBG R/W 0xFFFF.FFFE User Debug 146 0x1E0 USER_REG0 R/W 0x8FFF.FFFF User Register 0 147 0x1E4 USER_REG1 R/W 0x8FFF.FFFF User Register 1 148 0x204 FMPRE1 R/W 0xFFFF.FFFF Flash Memory Protection Read Enable 1 149 0x208 FMPRE2 R/W 0xFFFF.FFFF Flash Memory Protection Read Enable 2 150 0x20C FMPRE3 R/W 0xFFFF.FFFF Flash Memory Protection Read Enable 3 151 0x404 FMPPE1 R/W 0xFFFF.FFFF Flash Memory Protection Program Enable 1 152 0x408 FMPPE2 R/W 0xFFFF.FFFF Flash Memory Protection Program Enable 2 153 0x40C FMPPE3 R/W 0xFFFF.FFFF Flash Memory Protection Program Enable 3 154 8.5 Flash Register Descriptions (Flash Control Offset) The remainder of this section lists and describes the Flash Memory registers, in numerical order by address offset. June 14, 2007 135 Luminary Micro Confidential-Advance Product Information Internal Memory Register 1: Flash Memory Address (FMA), offset 0x000 During a write operation, this register contains a 4-byte-aligned address and specifies where the data is written. During erase operations, this register contains a 1 KB-aligned address and specifies which page is erased. Note that the alignment requirements must be met by software or the results of the operation are unpredictable. Flash Memory Address (FMA) Base 0x400F.D000 Offset 0x000 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 OFFSET Type Reset OFFSET Type Reset Bit/Field Name Type Reset 31:0 OFFSET R/W 0x0 Description Address offset in flash where operation is performed, except for nonvolatile registers (see “Nonvolatile Register Programming” on page 134 for details on values for this field). 136 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: Flash Memory Data (FMD), offset 0x004 This register contains the data to be written during the programming cycle or read during the read cycle. Note that the contents of this register are undefined for a read access of an execute-only block. This register is not used during the erase cycles. Flash Memory Data (FMD) Base 0x400F.D000 Offset 0x004 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 DATA Type Reset DATA Type Reset Bit/Field Name Type Reset 31:0 DATA R/W 0x0 Description Data value for write operation. June 14, 2007 137 Luminary Micro Confidential-Advance Product Information Internal Memory Register 3: Flash Memory Control (FMC), offset 0x008 When this register is written, the flash controller initiates the appropriate access cycle for the location specified by the Flash Memory Address (FMA) register (see page 136). If the access is a write access, the data contained in the Flash Memory Data (FMD) register (see page 137) is written. This is the final register written and initiates the memory operation. There are four control bits in the lower byte of this register that, when set, initiate the memory operation. The most used of these register bits are the ERASE and WRITE bits. It is a programming error to write multiple control bits and the results of such an operation are unpredictable. Flash Memory Control (FMC) Base 0x400F.D000 Offset 0x008 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 WRKEY Type Reset reserved Type Reset COMT R/W 0 MERASE ERASE R/W 0 R/W 0 WRITE R/W 0 Bit/Field Name Type Reset Description 31:16 WRKEY WO 0x0 This field contains a write key, which is used to minimize the incidence of accidental flash writes. The value 0xA442 must be written into this field for a write to occur. Writes to the FMC register without this WRKEY value are ignored. A read of this field returns the value 0. 15:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 COMT R/W 0 Commit (write) of register value to nonvolatile storage. A write of 0 has no effect on the state of this bit. If read, the state of the previous commit access is provided. If the previous commit access is complete, a 0 is returned; otherwise, if the commit access is not complete, a 1 is returned. This can take up to 50 μs. 2 MERASE R/W 0 Mass erase flash memory. If this bit is set, the flash main memory of the device is all erased. A write of 0 has no effect on the state of this bit. If read, the state of the previous mass erase access is provided. If the previous mass erase access is complete, a 0 is returned; otherwise, if the previous mass erase access is not complete, a 1 is returned. This can take up to 250 ms. 138 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 1 ERASE R/W 0 Description Erase a page of flash memory. If this bit is set, the page of flash main memory as specified by the contents of FMA is erased. A write of 0 has no effect on the state of this bit. If read, the state of the previous erase access is provided. If the previous erase access is complete, a 0 is returned; otherwise, if the previous erase access is not complete, a 1 is returned. This can take up to 25 ms. 0 WRITE R/W 0 Write a word into flash memory. If this bit is set, the data stored in FMD is written into the location as specified by the contents of FMA. A write of 0 has no effect on the state of this bit. If read, the state of the previous write update is provided. If the previous write access is complete, a 0 is returned; otherwise, if the write access is not complete, a 1 is returned. This can take up to 50 µs. June 14, 2007 139 Luminary Micro Confidential-Advance Product Information Internal Memory Register 4: Flash Controller Raw Interrupt Status (FCRIS), offset 0x00C This register indicates that the flash controller has an interrupt condition. An interrupt is only signaled if the corresponding FCIM register bit is set. Flash Controller Raw Interrupt Status (FCRIS) Base 0x400F.D000 Offset 0x00C Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 PRIS ARIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 PRIS RO 0 Programming Raw Interrupt Status This bit indicates the current state of the programming cycle. If set, the programming cycle completed; if cleared, the programming cycle has not completed. Programming cycles are either write or erase actions generated through the Flash Memory Control (FMC) register bits (see page 138). 0 ARIS RO 0 Access Raw Interrupt Status This bit indicates if the flash was improperly accessed. If set, the program tried to access the flash counter to the policy as set in the Flash Memory Protection Read Enable (FMPREn) and Flash Memory Protection Program Enable (FMPPEn) registers. Otherwise, no access has tried to improperly access the flash. 140 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 5: Flash Controller Interrupt Mask (FCIM), offset 0x010 This register controls whether the flash controller generates interrupts to the controller. Flash Controller Interrupt Mask (FCIM) Base 0x400F.D000 Offset 0x010 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 PMASK AMASK RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 PMASK R/W 0 Programming Interrupt Mask This bit controls the reporting of the programming raw interrupt status to the controller. If set, a programming-generated interrupt is promoted to the controller. Otherwise, interrupts are recorded but suppressed from the controller. 0 AMASK R/W 0 Access Interrupt Mask This bit controls the reporting of the access raw interrupt status to the controller. If set, an access-generated interrupt is promoted to the controller. Otherwise, interrupts are recorded but suppressed from the controller. June 14, 2007 141 Luminary Micro Confidential-Advance Product Information Internal Memory Register 6: Flash Controller Masked Interrupt Status and Clear (FCMISC), offset 0x014 This register provides two functions. First, it reports the cause of an interrupt by indicating which interrupt source or sources are signalling the interrupt. Second, it serves as the method to clear the interrupt reporting. Flash Controller Masked Interrupt Status and Clear (FCMISC) Base 0x400F.D000 Offset 0x014 Type R/W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 1 0 PMISC AMISC R/W1C 0 R/W1C 0 Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 PMISC R/W1C 0 Programming Masked Interrupt Status and Clear This bit indicates whether an interrupt was signaled because a programming cycle completed and was not masked. This bit is cleared by writing a 1. The PRIS bit in the FCRIS register (see page 140) is also cleared when the PMISC bit is cleared. 0 AMISC R/W1C 0 Access Masked Interrupt Status and Clear This bit indicates whether an interrupt was signaled because an improper access was attempted and was not masked. This bit is cleared by writing a 1. The ARIS bit in the FCRIS register is also cleared when the AMISC bit is cleared. 8.6 Flash Register Descriptions (System Control Offset) The remainder of this section lists and describes the Flash Memory registers, in numerical order by address offset. 142 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 7: USec Reload (USECRL), offset 0x140 Note: Offset is relative to System Control base address of 0x400F.E000 This register is provided as a means of creating a 1-μs tick divider reload value for the flash controller. The internal flash has specific minimum and maximum requirements on the length of time the high voltage write pulse can be applied. It is required that this register contain the operating frequency (in MHz -1) whenever the flash is being erased or programmed. The user is required to change this value if the clocking conditions are changed for a flash erase/program operation. USec Reload (USECRL) Base 0x400F.E000 Offset 0x140 Type R/W, reset 0x31 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 USEC RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 USEC R/W 0x31 RO 0 R/W 0 R/W 0 R/W 1 R/W 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. MHz -1 of the controller clock when the flash is being erased or programmed. USEC should be set to 0x31 (50 MHz) whenever the flash is being erased or programmed. June 14, 2007 143 Luminary Micro Confidential-Advance Product Information Internal Memory Register 8: Flash Memory Protection Read Enable 0 (FMPRE0), offset 0x130 and 0x200 Note: This register is aliased for backwards compatability. Note: Offset is relative to System Control base address of 0x400FE000. This register stores the read-only protection bits for each 2-KB flash block (FMPPEn stores the execute-only bits). This register is loaded during the power-on reset sequence. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see the "Flash Memory Protection" section. Flash Memory Protection Read Enable 0 (FMPRE0) Base 0x400F.D000 Offset 0x130 and 0x200 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 READ_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 READ_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type 31:0 READ_ENABLE R/W R/W 1 R/W 1 Reset R/W 1 R/W 1 Description 0xFFFFFFFF Enables 2-KB flash blocks to be executed or read. The policies may be combined as shown in the table “Flash Protection Policy Combinations”. Value Description 0xFFFFFFFF Enables 256 KB of flash. 144 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 9: Flash Memory Protection Program Enable 0 (FMPPE0), offset 0x134 and 0x400 Note: This register is aliased for backwards compatability. Note: Offset is relative to System Control base address of 0x400FE000. This register stores the execute-only protection bits for each 2-KB flash block (FMPREn stores the execute-only bits). This register is loaded during the power-on reset sequence. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see the "Flash Memory Protection" section. Flash Memory Protection Program Enable 0 (FMPPE0) Base 0x400F.D000 Offset 0x134 and 0x400 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 PROG_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 PROG_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type 31:0 PROG_ENABLE R/W R/W 1 R/W 1 Reset R/W 1 R/W 1 Description 0xFFFFFFFF Enables 2-KB flash blocks to be written or erased. The policies may be combined as shown in the table “Flash Protection Policy Combinations”. Value Description 0xFFFFFFFF Enables 256 KB of flash. June 14, 2007 145 Luminary Micro Confidential-Advance Product Information Internal Memory Register 10: User Debug (USER_DBG), offset 0x1D0 Note: Offset is relative to System Control base address of 0x400FE000. This register provides a write-once mechanism to disable external debugger access to the device in addition to 27 additional bits of user-defined data. The DBG0 bit (bit 0) is set to 0 from the factory and the DBG1 bit (bit 1) is set to 1, which enables external debuggers. Changing the DBG1 bit to 0 disables any external debugger access to the device permanently, starting with the next power-up cycle of the device. The NOTWRITTEN bit (bit 31) indicates that the register is available to be written and is controlled through hardware to ensure that the register is only written once. User Debug (USER_DBG) Base 0x400F.E000 Offset 0x1D0 Type R/W, reset 0xFFFF.FFFE 31 30 29 28 27 26 25 24 NOTWRITTEN Type Reset 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 DATA R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 9 8 7 6 5 4 3 DATA Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 2 1 0 INIT1 DBG1 DBG0 R/W 1 R/W 1 R/W 0 Bit/Field Name Type Reset Description 31 NOTWRITTEN R/W 1 30:3 DATA R/W 2 INIT1 R/W 1 User data initialized to 1. 1 DBG1 R/W 1 The DBG1 bit must be 1 and DBG0 must be 0 for debug to be available. 0 DBG0 R/W 0 The DBG1 bit must be 1 and DBG0 must be 0 for debug to be available. Specifies that this 32-bit dword has not been written. 0xFFFFFFF Contains the user data value. This field is initialized to all 1s and can only be written once. 146 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 11: User Register 0 (USER_REG0), offset 0x1E0 Note: Offset is relative to System Control base address of 0x400FE000. This register provides 31 bits of user-defined data that is non-volatile and can only be written once. Bit 31 indicates that the register is available to be written and is controlled through hardware to ensure that the register is only written once. The write-once characteristics of this register are useful for keeping static information like communication addresses that need to be unique per part and would otherwise require an external EEPROM or other non-volatile device. User Register 0 (USER_REG0) Base 0x400F.E000 Offset 0x1E0 Type R/W, reset 0x8FFF.FFFF 31 30 29 28 27 26 25 24 NOTWRITTEN Type Reset 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 DATA R/W 1 R/W 0 R/W 0 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 DATA Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type Reset 31 NOTWRITTEN R/W 1 30:0 DATA R/W R/W 1 Description Specifies that this 32-bit dword has not been written. 0xFFFFFFF Contains the user data value. This field is initialized to all 1s and can only be written once. June 14, 2007 147 Luminary Micro Confidential-Advance Product Information Internal Memory Register 12: User Register 1 (USER_REG1), offset 0x1E4 Note: Offset is relative to System Control base address of 0x400FE000. This register provides 31 bits of user-defined data that is non-volatile and can only be written once. Bit 31 indicates that the register is available to be written and is controlled through hardware to ensure that the register is only written once. The write-once characteristics of this register are useful for keeping static information like communication addresses that need to be unique per part and would otherwise require an external EEPROM or other non-volatile device. User Register 1 (USER_REG1) Base 0x400F.E000 Offset 0x1E4 Type R/W, reset 0x8FFF.FFFF 31 30 29 28 27 26 25 24 NOTWRITTEN Type Reset 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 DATA R/W 1 R/W 0 R/W 0 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 DATA Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type Reset 31 NOTWRITTEN R/W 1 30:0 DATA R/W R/W 1 Description Specifies that this 32-bit dword has not been written. 0xFFFFFFF Contains the user data value. This field is initialized to all 1s and can only be written once. 148 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 13: Flash Memory Protection Read Enable 1 (FMPRE1), offset 0x204 Note: Offset is relative to System Control base address of 0x400FE000. This register stores the read-only protection bits for each 2-KB flash block (FMPPEn stores the execute-only bits). This register is loaded during the power-on reset sequence. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see the "Flash Memory Protection" section. Flash Memory Protection Read Enable 1 (FMPRE1) Base 0x400F.E000 Offset 0x204 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 READ_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 READ_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type 31:0 READ_ENABLE R/W R/W 1 R/W 1 Reset R/W 1 R/W 1 Description 0xFFFFFFFF Enables 2-KB flash blocks to be executed or read. The policies may be combined as shown in the table “Flash Protection Policy Combinations”. Value Description 0xFFFFFFFF Enables 256 KB of flash. June 14, 2007 149 Luminary Micro Confidential-Advance Product Information Internal Memory Register 14: Flash Memory Protection Read Enable 2 (FMPRE2), offset 0x208 Note: Offset is relative to System Control base address of 0x400FE000. This register stores the read-only protection bits for each 2-KB flash block (FMPPEn stores the execute-only bits). This register is loaded during the power-on reset sequence. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see the "Flash Memory Protection" section. Flash Memory Protection Read Enable 2 (FMPRE2) Base 0x400F.E000 Offset 0x208 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 READ_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 READ_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type 31:0 READ_ENABLE R/W R/W 1 R/W 1 Reset R/W 1 R/W 1 Description 0xFFFFFFFF Enables 2-KB flash blocks to be executed or read. The policies may be combined as shown in the table “Flash Protection Policy Combinations”. Value Description 0xFFFFFFFF Enables 256 KB of flash. 150 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 15: Flash Memory Protection Read Enable 3 (FMPRE3), offset 0x20C Note: Offset is relative to System Control base address of 0x400FE000. This register stores the read-only protection bits for each 2-KB flash block (FMPPEn stores the execute-only bits). This register is loaded during the power-on reset sequence. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see the "Flash Memory Protection" section. Flash Memory Protection Read Enable 3 (FMPRE3) Base 0x400F.E000 Offset 0x20C Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 READ_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 READ_ENABLE Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type 31:0 READ_ENABLE R/W R/W 1 R/W 1 Reset R/W 1 R/W 1 Description 0xFFFFFFFF Enables 2-KB flash blocks to be executed or read. The policies may be combined as shown in the table “Flash Protection Policy Combinations”. Value Description 0xFFFFFFFF Enables 256 KB of flash. June 14, 2007 151 Luminary Micro Confidential-Advance Product Information Internal Memory Register 16: Flash Memory Protection Program Enable 1 (FMPPE1), offset 0x404 Note: Offset is relative to System Control base address of 0x400FE000. This register stores the execute-only protection bits for each 2-KB flash block (FMPREn stores the execute-only bits). This register is loaded during the power-on reset sequence. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see the "Flash Memory Protection" section. Flash Memory Protection Program Enable 1 (FMPPE1) Base 0x400F.E000 Offset 0x404 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 PROG_ENABLE Type Reset PROG_ENABLE Type Reset Bit/Field Name Type 31:0 PROG_ENABLE R/W Reset R/W 1 R/W 1 Description 0xFFFFFFFF Enables 2-KB flash blocks to be written or erased. The policies may be combined as shown in the table “Flash Protection Policy Combinations”. Value Description 0xFFFFFFFF Enables 256 KB of flash. 152 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 17: Flash Memory Protection Program Enable 2 (FMPPE2), offset 0x408 Note: Offset is relative to System Control base address of 0x400FE000. This register stores the execute-only protection bits for each 2-KB flash block (FMPREn stores the execute-only bits). This register is loaded during the power-on reset sequence. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see the "Flash Memory Protection" section. Flash Memory Protection Program Enable 2 (FMPPE2) Base 0x400F.E000 Offset 0x408 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 PROG_ENABLE Type Reset PROG_ENABLE Type Reset Bit/Field Name Type 31:0 PROG_ENABLE R/W Reset R/W 1 R/W 1 Description 0xFFFFFFFF Enables 2-KB flash blocks to be written or erased. The policies may be combined as shown in the table “Flash Protection Policy Combinations”. Value Description 0xFFFFFFFF Enables 256 KB of flash. June 14, 2007 153 Luminary Micro Confidential-Advance Product Information Internal Memory Register 18: Flash Memory Protection Program Enable 3 (FMPPE3), offset 0x40C Note: Offset is relative to System Control base address of 0x400FE000. This register stores the execute-only protection bits for each 2-KB flash block (FMPREn stores the execute-only bits). This register is loaded during the power-on reset sequence. The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This achieves a policy of open access and programmability. The register bits may be changed by writing the specific register bit. However, this register is R/W0; the user can only change the protection bit from a 1 to a 0 (and may NOT change a 0 to a 1). The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. For additional information, see the "Flash Memory Protection" section. Flash Memory Protection Program Enable 3 (FMPPE3) Base 0x400F.E000 Offset 0x40C Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 PROG_ENABLE Type Reset PROG_ENABLE Type Reset Bit/Field Name Type 31:0 PROG_ENABLE R/W Reset R/W 1 R/W 1 Description 0xFFFFFFFF Enables 2-KB flash blocks to be written or erased. The policies may be combined as shown in the table “Flash Protection Policy Combinations”. Value Description 0xFFFFFFFF Enables 256 KB of flash. 154 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 9 General-Purpose Input/Outputs (GPIOs) GPIO The GPIO module is composed of seven physical GPIO blocks, each corresponding to an individual GPIO port (Port A, Port B, Port C, Port D, Port E, Port F, and Port G, ). The GPIO module is FiRM-compliant and supports 3-38 programmable input/output pins, depending on the peripherals being used. The GPIO module has the following features: ■ Programmable control for GPIO interrupts – Interrupt generation masking – Edge-triggered on rising, falling, or both – Level-sensitive on High or Low values ■ 5-V-tolerant input/outputs ■ Bit masking in both read and write operations through address lines ■ Programmable control for GPIO pad configuration – Weak pull-up or pull-down resistors – 2-mA, 4-mA, and 8-mA pad drive – Slew rate control for the 8-mA drive – Open drain enables – Digital input enables 9.1 Function Description Important: All GPIO pins are tri-stated by default (GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0, and GPIOPUR=0), with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). The JTAG/SWD pins default to their JTAG/SWD functionality (GPIOAFSEL=1, GPIODEN=1 and GPIOPUR=1). A Power-On-Reset (POR) or asserting RST puts both groups of pins back to their default state. Each GPIO port is a separate hardware instantiation of the same physical block. The LM3S8938 microcontroller contains seven ports and thus seven of these physical GPIO blocks. 9.1.1 Data Control The data control registers allow software to configure the operational modes of the GPIOs. The data direction register configures the GPIO as an input or an output while the data register either captures incoming data or drives it out to the pads. 9.1.1.1 Data Direction Operation The GPIO Direction (GPIODIR) register (see page 163) is used to configure each individual pin as an input or output. When the data direction bit is set to 0, the GPIO is configured as an input and June 14, 2007 155 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) the corresponding data register bit will capture and store the value on the GPIO port. When the data direction bit is set to 1, the GPIO is configured as an output and the corresponding data register bit will be driven out on the GPIO port. 9.1.1.2 Data Register Operation To aid in the efficiency of software, the GPIO ports allow for the modification of individual bits in the GPIO Data (GPIODATA) register (see page 162) by using bits [9:2] of the address bus as a mask. This allows software drivers to modify individual GPIO pins in a single instruction, without affecting the state of the other pins. This is in contrast to the "typical" method of doing a read-modify-write operation to set or clear an individual GPIO pin. To accommodate this feature, the GPIODATA register covers 256 locations in the memory map. During a write, if the address bit associated with that data bit is set to 1, the value of the GPIODATA register is altered. If it is cleared to 0, it is left unchanged. For example, writing a value of 0xEB to the address GPIODATA + 0x098 would yield as shown in Figure 9-1 on page 156, where u is data unchanged by the write. Figure 9-1. GPIODATA Write Example ADDR[9:2] 0x098 9 8 7 6 5 4 3 2 1 0 0 0 1 0 0 1 1 0 1 0 0xEB 1 1 1 0 1 0 1 1 GPIODATA u u 1 u u 0 1 u 7 6 5 4 3 2 1 0 During a read, if the address bit associated with the data bit is set to 1, the value is read. If the address bit associated with the data bit is set to 0, it is read as a zero, regardless of its actual value. For example, reading address GPIODATA + 0x0C4 yields as shown in Figure 9-2 on page 156. Figure 9-2. GPIODATA Read Example 9.1.2 ADDR[9:2] 0x0C4 9 8 7 6 5 4 3 2 1 0 0 0 1 1 0 0 0 1 0 0 GPIODATA 1 0 1 1 1 1 1 0 Returned Value 0 0 1 1 0 0 0 0 7 6 5 4 3 2 1 0 Interrupt Control The interrupt capabilities of each GPIO port are controlled by a set of seven registers. With these registers, it is possible to select the source of the interrupt, its polarity, and the edge properties. When one or more GPIO inputs cause an interrupt, a single interrupt output is sent to the interrupt controller for the entire GPIO port. For edge-triggered interrupts, software must clear the interrupt to enable any further interrupts. For a level-sensitive interrupt, it is assumed that the external source holds the level constant for the interrupt to be recognized by the controller. Three registers are required to define the edge or sense that causes interrupts: 156 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller ■ GPIO Interrupt Sense (GPIOIS) register (see page 164) ■ GPIO Interrupt Both Edges (GPIOIBE) register (see page 165) ■ GPIO Interrupt Event (GPIOIEV) register (see page 166) Interrupts are enabled/disabled via the GPIO Interrupt Mask (GPIOIM) register (see page 167). When an interrupt condition occurs, the state of the interrupt signal can be viewed in two locations: the GPIO Raw Interrupt Status (GPIORIS) and GPIO Masked Interrupt Status (GPIOMIS) registers (see page 168 and page 169). As the name implies, the GPIOMIS register only shows interrupt conditions that are allowed to be passed to the controller. The GPIORIS register indicates that a GPIO pin meets the conditions for an interrupt, but has not necessarily been sent to the controller. In addition to providing GPIO functionality, PB4 can also be used as an external trigger for the ADC. If PB4 is configured as a non-masked interrupt pin (GPIOIM is set to 1), not only is an interrupt for PortB generated, but an external trigger signal is sent to the ADC. If the ADC Event Multiplexer Select (ADCEMUX) register is configured to use the external trigger, an ADC conversion is initiated. If no other PortB pins are being used to generate interrupts, the ARM Integrated Nested Vectored Interrupt Controller (NVIC) Interrupt Set Enable (SETNA) register can disable the PortB interrupts and the ADC interrupt can be used to read back the converted data. Otherwise, the PortB interrupt handler needs to ignore and clear interrupts on B4, and wait for the ADC interrupt or the ADC interrupt needs to be disabled in the SETNA register and the PortB interrupt handler polls the ADC registers until the conversion is completed. Interrupts are cleared by writing a 1 to the GPIO Interrupt Clear (GPIOICR) register (see page 170). When programming the following interrupt control registers, the interrupts should be masked (GPIOIM set to 0). Writing any value to an interrupt control register (GPIOIS, GPIOIBE, or GPIOIEV) can generate a spurious interrupt if the corresponding bits are enabled. 9.1.3 Mode Control The GPIO pins can be controlled by either hardware or software. When hardware control is enabled via the GPIO Alternate Function Select (GPIOAFSEL) register (see page 171), the pin state is controlled by its alternate function (that is, the peripheral). Software control corresponds to GPIO mode, where the GPIODATA register is used to read/write the corresponding pins. 9.1.4 Commit Control The commit control registers provide a layer of protection against accidental programming of critical hardware peripherals. Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL) register (see page 171) are not committed to storage unless the GPIO Lock (GPIOLOCK) register (see page 181) has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register (see page 182) have been set to 1. 9.1.5 Pad Control The pad control registers allow for GPIO pad configuration by software based on the application requirements. The pad control registers include the GPIODR2R, GPIODR4R, GPIODR8R, GPIOODR, GPIOPUR, GPIOPDR, GPIOSLR, and GPIODEN registers. June 14, 2007 157 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) 9.1.6 Identification The identification registers configured at reset allow software to detect and identify the module as a GPIO block. The identification registers include the GPIOPeriphID0-GPIOPeriphID7 registers as well as the GPIOPCellID0-GPIOPCellID3 registers. 9.2 Initialization and Configuration To use the GPIO, the peripheral clock must be enabled by setting the appropriate GPIO Port bit field (GPIOn) in the RCGC2 register. On reset, all GPIO pins (except for the five JTAG pins) are configured out of reset to be undriven (tristate): GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0, and GPIOPUR=0. Table 9-1 on page 158 shows all possible configurations of the GPIO pads and the control register settings required to achieve them. Table 9-2 on page 158 shows how a rising edge interrupt would be configured for pin 2 of a GPIO port. Table 9-1. GPIO Pad Configuration Examples a Configuration GPIO Register Bit Value AFSEL DIR ODR DEN PUR PDR ? ? DR2R DR4R DR8R X X X SLR Digital Input (GPIO) 0 0 0 1 X Digital Output (GPIO) 0 1 0 1 ? ? ? ? ? ? Open Drain Input (GPIO) 0 0 1 1 X X X X X X Open Drain Output (GPIO) 0 1 1 1 X X ? ? ? ? Open Drain 2 Input/Output (I C) 1 X 1 1 X X ? ? ? ? Digital Input (Timer CCP) 1 X 0 1 ? ? X X X X Digital Output (Timer PWM) 1 X 0 1 ? ? ? ? ? ? Digital Input/Output (SSI) 1 X 0 1 ? ? ? ? ? ? Digital Input/Output (UART) 1 X 0 1 ? ? ? ? ? ? Analog Input (Comparator) 0 0 0 0 0 0 X X X X Digital Output (Comparator) 1 X 0 1 ? ? ? ? ? ? a. X=Ignored (don’t care bit) ?=Can be either 0 or 1, depending on the configuration Table 9-2. GPIO Interrupt Configuration Example Register GPIOIS Desired Interrupt Event Trigger 0=edge a Pin 2 Bit Value 7 6 X 5 X 4 X 3 X 2 X 1 0 0 X X 1=level 158 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register GPIOIBE a Desired Interrupt Event Trigger Pin 2 Bit Value 7 0=single edge 6 5 4 3 2 1 0 X X X X X 0 X X X X X X X 1 X X 0 0 0 0 0 1 0 0 1=both edges GPIOIEV 0=Low level, or negative edge 1=High level, or positive edge GPIOIM 0=masked 1=not masked a. X=Ignored (don’t care bit) 9.3 Register Map Table 9-3 on page 160 lists the GPIO registers. The offset listed is a hexadecimal increment to the register’s address, relative to that GPIO port’s base address: ■ GPIO Port A: 0x4000.4000 ■ GPIO Port B: 0x4000.5000 ■ GPIO Port C: 0x4000.6000 ■ GPIO Port D: 0x4000.7000 ■ GPIO Port E: 0x4002.4000 ■ GPIO Port F: 0x4002.5000 ■ GPIO Port G: 0x4002.6000 Important: The GPIO registers in this chapter are duplicated in each GPIO block, however, depending on the block, all eight bits may not be connected to a GPIO pad. In those cases, writing to those unconnected bits has no effect and reading those unconnected bits returns no meaningful data. Note: The default reset value for the GPIOAFSEL, GPIOPUR, and GPIODEN registers are 0x0000.0000 for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). These five pins default to JTAG/SWD functionality. Because of this, the default reset value of these registers for GPIO Port B is 0x0000.0080 while the default reset value for Port C is 0x0000.000F. The default register type for the GPIOCR register is RO for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). These five pins are currently the only GPIOs that are protected by the GPIOCR register. Because of this, the register type for GPIO Port B7 and GPIO Port C[3:0] is R/W. June 14, 2007 159 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) The default reset value for the GPIOCR register is 0x0000.00FF for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). To ensure that the JTAG port is not accidentally programmed as a GPIO, these five pins default to non-commitable. Because of this, the default reset value of GPIOCR for GPIO Port B is 0x0000.007F while the default reset value of GPIOCR for Port C is 0x0000.00F0. Table 9-3. GPIO Register Map Description See page Offset Name Type Reset 0x000 GPIODATA R/W 0x0000.0000 GPIO Data 162 0x400 GPIODIR R/W 0x0000.0000 GPIO Direction 163 0x404 GPIOIS R/W 0x0000.0000 GPIO Interrupt Sense 164 0x408 GPIOIBE R/W 0x0000.0000 GPIO Interrupt Both Edges 165 0x40C GPIOIEV R/W 0x0000.0000 GPIO Interrupt Event 166 0x410 GPIOIM R/W 0x0000.0000 GPIO Interrupt Mask 167 0x414 GPIORIS RO 0x0000.0000 GPIO Raw Interrupt Status 168 0x418 GPIOMIS RO 0x0000.0000 GPIO Masked Interrupt Status 169 0x41C GPIOICR W1C 0x0000.0000 GPIO Interrupt Clear 170 0x420 GPIOAFSEL R/W - GPIO Alternate Function Select 171 0x500 GPIODR2R R/W 0x0000.00FF GPIO 2-mA Drive Select 173 0x504 GPIODR4R R/W 0x0000.0000 GPIO 4-mA Drive Select 174 0x508 GPIODR8R R/W 0x0000.0000 GPIO 8-mA Drive Select 175 0x50C GPIOODR R/W 0x0000.0000 GPIO Open Drain Select 176 0x510 GPIOPUR R/W - GPIO Pull-Up Select 177 0x514 GPIOPDR R/W 0x0000.0000 GPIO Pull-Down Select 178 0x518 GPIOSLR R/W 0x0000.0000 GPIO Slew Rate Control Select 179 0x51C GPIODEN R/W - GPIO Digital Enable 180 0x520 GPIOLOCK R/W 0x0000.0001 GPIO Lock 181 0x524 GPIOCR - - GPIO Commit 182 0xFD0 GPIOPeriphID4 RO 0x0x0000.0000 GPIO Peripheral Identification 4 184 0xFD4 GPIOPeriphID5 RO 0x0x0000.0000 GPIO Peripheral Identification 5 185 0xFD8 GPIOPeriphID6 RO 0x0x0000.0000 GPIO Peripheral Identification 6 186 0xFDC GPIOPeriphID7 RO 0x0x0000.0000 GPIO Peripheral Identification 7 187 0xFE0 GPIOPeriphID0 RO 0x0x0000.0061 GPIO Peripheral Identification 0 188 0xFE4 GPIOPeriphID1 RO 0x0x0000.0000 GPIO Peripheral Identification 1 189 0xFE8 GPIOPeriphID2 RO 0x0x0000.0018 GPIO Peripheral Identification 2 190 0xFEC GPIOPeriphID3 RO 0x0x0000.0001 GPIO Peripheral Identification 3 191 160 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Offset Name 0xFF0 Reset GPIOPCellID0 RO 0x0x0000.000D GPIO PrimeCell Identification 0 192 0xFF4 GPIOPCellID1 RO 0x0x0000.00F0 GPIO PrimeCell Identification 1 193 0xFF8 GPIOPCellID2 RO 0x0x0000.0005 GPIO PrimeCell Identification 2 194 0xFFC GPIOPCellID3 RO 0x0x0000.00B1 GPIO PrimeCell Identification 3 195 9.4 Description See page Type Register Descriptions The remainder of this section lists and describes the GPIO registers, in numerical order by address offset. June 14, 2007 161 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 1: GPIO Data (GPIODATA), offset 0x000 The GPIODATA register is the data register. In software control mode, values written in the GPIODATA register are transferred onto the GPIO port pins if the respective pins have been configured as outputs through the GPIO Direction (GPIODIR) register (see page 163). In order to write to GPIODATA, the corresponding bits in the mask, resulting from the address bus bits [9:2], must be High. Otherwise, the bit values remain unchanged by the write. Similarly, the values read from this register are determined for each bit by the mask bit derived from the address used to access the data register, bits [9:2]. Bits that are 1 in the address mask cause the corresponding bits in GPIODATA to be read, and bits that are 0 in the address mask cause the corresponding bits in GPIODATA to be read as 0, regardless of their value. A read from GPIODATA returns the last bit value written if the respective pins are configured as outputs, or it returns the value on the corresponding input pin when these are configured as inputs. All bits are cleared by a reset. GPIO Data (GPIODATA) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x000 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset DATA RO 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 DATA R/W 0 GPIO Data This register is virtually mapped to 256 locations in the address space. To facilitate the reading and writing of data to these registers by independent drivers, the data read from and the data written to the registers are masked by the eight address lines ipaddr[9:2]. Reads from this register return its current state. Writes to this register only affect bits that are not masked by ipaddr[9:2] and are configured as outputs. See “Data Register Operation” on page 156 for examples of reads and writes. 162 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: GPIO Direction (GPIODIR), offset 0x400 The GPIODIR register is the data direction register. Bits set to 1 in the GPIODIR register configure the corresponding pin to be an output, while bits set to 0 configure the pins to be inputs. All bits are cleared by a reset, meaning all GPIO pins are inputs by default. GPIO Direction (GPIODIR) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x400 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 DIR RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 DIR R/W 0x00 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Data Direction 0: Pins are inputs. 1: Pins are outputs. June 14, 2007 163 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 3: GPIO Interrupt Sense (GPIOIS), offset 0x404 The GPIOIS register is the interrupt sense register. Bits set to 1 in GPIOIS configure the corresponding pins to detect levels, while bits set to 0 configure the pins to detect edges. All bits are cleared by a reset. GPIO Interrupt Sense (GPIOIS) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x404 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 IS RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 IS R/W 0x00 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Interrupt Sense 0: Edge on corresponding pin is detected (edge-sensitive). 1: Level on corresponding pin is detected (level-sensitive). 164 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 4: GPIO Interrupt Both Edges (GPIOIBE), offset 0x408 The GPIOIBE register is the interrupt both-edges register. When the corresponding bit in the GPIO Interrupt Sense (GPIOIS) register (see page 164) is set to detect edges, bits set to High in GPIOIBE configure the corresponding pin to detect both rising and falling edges, regardless of the corresponding bit in the GPIO Interrupt Event (GPIOIEV) register (see page 166). Clearing a bit configures the pin to be controlled by GPIOIEV. All bits are cleared by a reset. GPIO Interrupt Both Edges (GPIOIBE) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x408 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 IBE RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 IBE R/W 0x00 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Interrupt Both Edges 0: Interrupt generation is controlled by the GPIO Interrupt Event (GPIOIEV)register (see page 142). 1: Both edges on the corresponding pin trigger an interrupt. Note: Single edge is determined by the corresponding bit in GPIOIEV. June 14, 2007 165 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 5: GPIO Interrupt Event (GPIOIEV), offset 0x40C The GPIOIEV register is the interrupt event register. Bits set to High in GPIOIEV configure the corresponding pin to detect rising edges or high levels, depending on the corresponding bit value in the GPIO Interrupt Sense (GPIOIS) register (see page 164). Clearing a bit configures the pin to detect falling edges or low levels, depending on the corresponding bit value in GPIOIS. All bits are cleared by a reset. GPIO Interrupt Event (GPIOIEV) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x40C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 IEV RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 IEV R/W 0x00 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Interrupt Event 0: Falling edge or Low levels on corresponding pins trigger interrupts. 1: Rising edge or High levels on corresponding pins trigger interrupts. 166 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: GPIO Interrupt Mask (GPIOIM), offset 0x410 The GPIOIM register is the interrupt mask register. Bits set to High in GPIOIM allow the corresponding pins to trigger their individual interrupts and the combined GPIOINTR line. Clearing a bit disables interrupt triggering on that pin. All bits are cleared by a reset. GPIO Interrupt Mask (GPIOIM) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x410 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 IME RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 IME R/W 0x00 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Interrupt Mask Enable 0: Corresponding pin interrupt is masked. 1: Corresponding pin interrupt is not masked. June 14, 2007 167 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 7: GPIO Raw Interrupt Status (GPIORIS), offset 0x414 The GPIORIS register is the raw interrupt status register. Bits read High in GPIORIS reflect the status of interrupt trigger conditions detected (raw, prior to masking), indicating that all the requirements have been met, before they are finally allowed to trigger by the GPIO Interrupt Mask (GPIOIM) register (see page 167). Bits read as zero indicate that corresponding input pins have not initiated an interrupt. All bits are cleared by a reset. GPIO Raw Interrupt Status (GPIORIS) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x414 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RIS RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 RIS RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Interrupt Raw Status Reflect the status of interrupt trigger condition detection on pins (raw, prior to masking). 0: Corresponding pin interrupt requirements not met. 1: Corresponding pin interrupt has met requirements. 168 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 8: GPIO Masked Interrupt Status (GPIOMIS), offset 0x418 The GPIOMIS register is the masked interrupt status register. Bits read High in GPIOMIS reflect the status of input lines triggering an interrupt. Bits read as Low indicate that either no interrupt has been generated, or the interrupt is masked. In addition to providing GPIO functionality, PB4 can also be used as an external trigger for the ADC. If PB4 is configured as a non-masked interrupt pin (GPIOIM is set to 1), not only is an interrupt for PortB generated, but an external trigger signal is sent to the ADC. If the ADC Event Multiplexer Select (ADCEMUX) register is configured to use the external trigger, an ADC conversion is initiated. If no other PortB pins are being used to generate interrupts, the ARM Integrated Nested Vectored Interrupt Controller (NVIC) Interrupt Set Enable (SETNA) register can disable the PortB interrupts and the ADC interrupt can be used to read back the converted data. Otherwise, the PortB interrupt handler needs to ignore and clear interrupts on B4, and wait for the ADC interrupt or the ADC interrupt needs to be disabled in the SETNA register and the PortB interrupt handler polls the ADC registers until the conversion is completed. GPIOMIS is the state of the interrupt after masking. GPIO Masked Interrupt Status (GPIOMIS) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x418 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset MIS RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 MIS RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Masked Interrupt Status Masked value of interrupt due to corresponding pin. 0: Corresponding GPIO line interrupt not active. 1: Corresponding GPIO line asserting interrupt. June 14, 2007 169 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 9: GPIO Interrupt Clear (GPIOICR), offset 0x41C The GPIOICR register is the interrupt clear register. Writing a 1 to a bit in this register clears the corresponding interrupt edge detection logic register. Writing a 0 has no effect. GPIO Interrupt Clear (GPIOICR) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x41C Type W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 W1C 0 W1C 0 W1C 0 W1C 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 IC RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 IC W1C 0x00 RO 0 W1C 0 W1C 0 W1C 0 W1C 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Interrupt Clear 0: Corresponding interrupt is unaffected. 1: Corresponding interrupt is cleared. 170 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 10: GPIO Alternate Function Select (GPIOAFSEL), offset 0x420 The GPIOAFSEL register is the mode control select register. Writing a 1 to any bit in this register selects the hardware control for the corresponding GPIO line. All bits are cleared by a reset, therefore no GPIO line is set to hardware control by default. The commit control registers provide a layer of protection against accidental programming of critical hardware peripherals. Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL) register (see page 171) are not committed to storage unless the GPIO Lock (GPIOLOCK) register (see page 181) has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register (see page 182) have been set to 1. Important: All GPIO pins are tri-stated by default (GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0, and GPIOPUR=0), with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). The JTAG/SWD pins default to their JTAG/SWD functionality (GPIOAFSEL=1, GPIODEN=1 and GPIOPUR=1). A Power-On-Reset (POR) or asserting RST puts both groups of pins back to their default state. Caution – If the JTAG pins are used as GPIOs in a design, PB7 and PC2 cannot have external pull-down resistors connected to both of them at the same time. If both pins are pulled Low during reset, the controller has unpredictable behavior. If this happens, remove one or both of the pull-down resistors, and apply RST or power-cycle the part. In addition, it is possible to create a software sequence that prevents the debugger from connecting to the Stellaris® microcontroller. If the program code loaded into flash immediately changes the JTAG pins to their GPIO functionality, the debugger may not have enough time to connect and halt the controller before the JTAG pin functionality switches. This may lock the debugger out of the part. This can be avoided with a software routine that restores JTAG functionality based on an external or software trigger. GPIO Alternate Function Select (GPIOAFSEL) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x420 Type R/W, reset 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W - R/W - R/W - R/W - R/W - R/W - R/W - R/W - reserved Type Reset reserved Type Reset AFSEL RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 171 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Bit/Field Name Type Reset 7:0 AFSEL R/W - Description GPIO Alternate Function Select 0: Software control of corresponding GPIO line (GPIO mode). 1: Hardware control of corresponding GPIO line (alternate hardware function). Note: The default reset value for the GPIOAFSEL, GPIOPUR, and GPIODEN registers are 0x0000.0000 for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). These five pins default to JTAG/SWD functionality. Because of this, the default reset value of these registers for GPIO Port B is 0x0000.0080 while the default reset value for Port C is 0x0000.000F. 172 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 11: GPIO 2-mA Drive Select (GPIODR2R), offset 0x500 The GPIODR2R register is the 2-mA drive control register. It allows for each GPIO signal in the port to be individually configured without affecting the other pads. When writing a DRV2 bit for a GPIO signal, the corresponding DRV4 bit in the GPIODR4R register and the DRV8 bit in the GPIODR8R register are automatically cleared by hardware. GPIO 2-mA Drive Select (GPIODR2R) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x500 Type R/W, reset 0x0000.00FF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 DRV2 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 DRV2 R/W 0xFF RO 0 R/W 1 R/W 1 R/W 1 R/W 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Output Pad 2-mA Drive Enable A write of 1 to either GPIODR4[n] or GPIODR8[n]clears the corresponding 2-mA enable bit. The change is effective on the second clock cycle after the write. June 14, 2007 173 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 12: GPIO 4-mA Drive Select (GPIODR4R), offset 0x504 The GPIODR4R register is the 4-mA drive control register. It allows for each GPIO signal in the port to be individually configured without affecting the other pads. When writing the DRV4 bit for a GPIO signal, the corresponding DRV2 bit in the GPIODR2R register and the DRV8 bit in the GPIODR8R register are automatically cleared by hardware. GPIO 4-mA Drive Select (GPIODR4R) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x504 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 DRV4 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 DRV4 R/W 0x00 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Output Pad 4-mA Drive Enable A write of 1 to either GPIODR2[n] or GPIODR8[n]clears the corresponding 4-mA enable bit. The change is effective on the second clock cycle after the write. 174 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 13: GPIO 8-mA Drive Select (GPIODR8R), offset 0x508 The GPIODR8R register is the 8-mA drive control register. It allows for each GPIO signal in the port to be individually configured without affecting the other pads. When writing the DRV8 bit for a GPIO signal, the corresponding DRV2 bit in the GPIODR2R register and the DRV4 bit in the GPIODR4R register are automatically cleared by hardware. GPIO 8-mA Drive Select (GPIODR8R) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x508 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 DRV8 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 DRV8 R/W 0x00 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Output Pad 8-mA Drive Enable A write of 1 to either GPIODR2[n] or GPIODR4[n]clears the corresponding 8-mA enable bit. The change is effective on the second clock cycle after the write. June 14, 2007 175 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 14: GPIO Open Drain Select (GPIOODR), offset 0x50C The GPIOODR register is the open drain control register. Setting a bit in this register enables the open drain configuration of the corresponding GPIO pad. When open drain mode is enabled, the corresponding bit should also be set in the GPIO Digital Input Enable (GPIODEN) register (see page 180). Corresponding bits in the drive strength registers (GPIODR2R, GPIODR4R, GPIODR8R, and GPIOSLR ) can be set to achieve the desired rise and fall times. The GPIO acts as an open drain input if the corresponding bit in the GPIODIR register is set to 0; and as an open drain output when set to 1. 2 When using the I C module, the GPIO Alternate Function Select (GPIOAFSEL) register bit for PB2 and PB3 should be set to 1 (see examples in “Initialization and Configuration” on page 158). GPIO Open Drain Select (GPIOODR) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x50C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset ODE RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 ODE R/W 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Output Pad Open Drain Enable 0: Open drain configuration is disabled. 1: Open drain configuration is enabled. 176 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 15: GPIO Pull-Up Select (GPIOPUR), offset 0x510 The GPIOPUR register is the pull-up control register. When a bit is set to 1, it enables a weak pull-up resistor on the corresponding GPIO signal. Setting a bit in GPIOPUR automatically clears the corresponding bit in the GPIO Pull-Down Select (GPIOPDR) register (see page 178). GPIO Pull-Up Select (GPIOPUR) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x510 Type R/W, reset 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W - R/W - R/W - R/W - reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PUE RO 0 RO 0 RO 0 RO 0 R/W - R/W - R/W - R/W - Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 PUE R/W - Pad Weak Pull-Up Enable A write of 1 to GPIOPDR[n]clears the corresponding GPIOPUR[n]enables. The change is effective on the second clock cycle after the write. Note: The default reset value for the GPIOAFSEL, GPIOPUR, and GPIODEN registers are 0x0000.0000 for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). These five pins default to JTAG/SWD functionality. Because of this, the default reset value of these registers for GPIO Port B is 0x0000.0080 while the default reset value for Port C is 0x0000.000F. June 14, 2007 177 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 16: GPIO Pull-Down Select (GPIOPDR), offset 0x514 The GPIOPDR register is the pull-down control register. When a bit is set to 1, it enables a weak pull-down resistor on the corresponding GPIO signal. Setting a bit in GPIOPDR automatically clears the corresponding bit in the GPIO Pull-Up Select (GPIOPUR) register (see page 177). GPIO Pull-Down Select (GPIOPDR) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x514 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PDE RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PDE R/W 0x00 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Pad Weak Pull-Down Enable A write of 1 to GPIOPUR[n]clears the corresponding GPIOPDR[n]enables. The change is effective on the second clock cycle after the write. 178 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 17: GPIO Slew Rate Control Select (GPIOSLR), offset 0x518 The GPIOSLR register is the slew rate control register. Slew rate control is only available when using the 8-mA drive strength option via the GPIO 8-mA Drive Select (GPIODR8R) register (see page 175). GPIO Slew Rate Control Select (GPIOSLR) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x518 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 SRL RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 SRL R/W 0 Slew Rate Limit Enable (8-mA drive only) 0: Slew rate control disabled. 1: Slew rate control enabled. June 14, 2007 179 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 18: GPIO Digital Enable (GPIODEN), offset 0x51C The GPIODEN register is the digital enable register. By default, with the exception of the GPIO signals used for JTAG/SWD function, all other GPIO signals are configured out of reset to be undriven (tristate). Their digital function is disabled; they do not drive a logic value on the pin and they do not allow the pin voltage into the GPIO receiver. To use the pin in a digital function (either GPIO or alternate function), the corresponding GPIODEN bit must be set. GPIO Digital Enable (GPIODEN) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x51C Type R/W, reset 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W - R/W - R/W - R/W - reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 DEN RO 0 RO 0 RO 0 RO 0 R/W - R/W - R/W - R/W - Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 DEN R/W - Digital Enable 0: Digital functions disabled. 1: Digital functions enabled. Note: The default reset value for the GPIOAFSEL, GPIOPUR, and GPIODEN registers are 0x0000.0000 for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). These five pins default to JTAG/SWD functionality. Because of this, the default reset value of these registers for GPIO Port B is 0x0000.0080 while the default reset value for Port C is 0x0000.000F. 180 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 19: GPIO Lock (GPIOLOCK), offset 0x520 The GPIOLOCK register enables write access to the GPIOCR register (see page 182). Writing 0x1ACCE551 to the GPIOLOCK register will unlock the GPIOCR register. Writing any other value to the GPIOLOCK register re-enables the locked state. Reading the GPIOLOCK register returns the lock status rather than the 32-bit value that was previously written. Therefore, when write accesses are disabled, or locked, reading the GPIOLOCK register returns 0x00000001. When write accesses are enabled, or unlocked, reading the GPIOLOCK register returns 0x00000000. GPIO Lock (GPIOLOCK) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x520 Type R/W, reset 0x0000.0001 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 1 LOCK Type Reset R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 15 14 13 12 11 10 9 8 LOCK Type Reset R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type 31:0 LOCK R/W R/W 0 R/W 0 Reset R/W 0 Description 0x00000001 GPIO Lock A write of the value 0x1ACCE551 unlocks the GPIO Commit register for write access. A write of any other value reapplies the lock, preventing any register updates. A read of this register returns the following values: locked: 0x00000001 unlocked: 0x00000000 June 14, 2007 181 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 20: GPIO Commit (GPIOCR), offset 0x524 The GPIOCR register is the commit register. The value of the GPIOCR register determines which bits of the GPIOAFSEL register will be committed when a write to the GPIOAFSEL register is performed. If a bit in the GPIOCR register is a zero, the data being written to the corresponding bit in the GPIOAFSEL register will not be committed and will retain its previous value. If a bit in the GPIOCR register is a one, the data being written to the corresponding bit of the GPIOAFSEL register will be committed to the register and will reflect the new value. The contents of the GPIOCR register can only be modified if the GPIOLOCK register is unlocked. Writes to the GPIOCR register will be ignored if the GPIOLOCK register is locked. Important: This register is designed to prevent accidental programming of the GPIOAFSEL registers that control connectivity to the JTAG/SWD debug hardware. By initializing the bits of the GPIOCR register to 0 for PB7 and PC[3:0], the JTAG/SWD debug port can only be converted to GPIOs through a deliberate set of writes to the GPIOLOCK, GPIOCR, and GPIOAFSEL registers. Because this protection is currently only implemented on the JTAG/SWD pins on PB7 and PC[3:0], all of the other bits in the GPIOCR registers cannot be written with 0x0. These bits are hardwired to 0x1, ensuring that it is always possible to commit new values to the GPIOAFSEL register bits of these other pins. GPIO Commit (GPIOCR) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0x524 Type -, reset 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 - - - - - - - - reserved Type Reset reserved Type Reset CR RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 182 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 7:0 CR - - Description GPIO Commit On a bit-wise basis, any bit set allows the corresponding GPIOAFSEL bit to be set to its alternate function. Note: The default register type for the GPIOCR register is RO for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). These five pins are currently the only GPIOs that are protected by the GPIOCR register. Because of this, the register type for GPIO Port B7 and GPIO Port C[3:0] is R/W. The default reset value for the GPIOCR register is 0x0000.00FF for all GPIO pins, with the exception of the five JTAG/SWD pins (PB7 and PC[3:0]). To ensure that the JTAG port is not accidentally programmed as a GPIO, these five pins default to non-commitable. Because of this, the default reset value of GPIOCR for GPIO Port B is 0x0000.007F while the default reset value of GPIOCR for Port C is 0x0000.00F0. June 14, 2007 183 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 21: GPIO Peripheral Identification 4 (GPIOPeriphID4), offset 0xFD0 The GPIOPeriphID4, GPIOPeriphID5, GPIOPeriphID6, and GPIOPeriphID7 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral. GPIO Peripheral Identification 4 (GPIOPeriphID4) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFD0 Type RO, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID4 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID4 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Peripheral ID Register[7:0] 184 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 22: GPIO Peripheral Identification 5 (GPIOPeriphID5), offset 0xFD4 The GPIOPeriphID4, GPIOPeriphID5, GPIOPeriphID6, and GPIOPeriphID7 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral. GPIO Peripheral Identification 5 (GPIOPeriphID5) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFD4 Type RO, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID5 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID5 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Peripheral ID Register[15:8] June 14, 2007 185 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 23: GPIO Peripheral Identification 6 (GPIOPeriphID6), offset 0xFD8 The GPIOPeriphID4, GPIOPeriphID5, GPIOPeriphID6, and GPIOPeriphID7 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral. GPIO Peripheral Identification 6 (GPIOPeriphID6) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFD8 Type RO, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID6 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID6 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Peripheral ID Register[23:16] 186 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 24: GPIO Peripheral Identification 7 (GPIOPeriphID7), offset 0xFDC The GPIOPeriphID4, GPIOPeriphID5, GPIOPeriphID6, and GPIOPeriphID7 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral. GPIO Peripheral Identification 7 (GPIOPeriphID7) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFDC Type RO, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID7 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID7 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Peripheral ID Register[31:24] June 14, 2007 187 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 25: GPIO Peripheral Identification 0 (GPIOPeriphID0), offset 0xFE0 The GPIOPeriphID0, GPIOPeriphID1, GPIOPeriphID2, and GPIOPeriphID3 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral. GPIO Peripheral Identification 0 (GPIOPeriphID0) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFE0 Type RO, reset 0x0x0000.0061 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID0 RO 0x61 RO 0 RO 0 RO 1 RO 1 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Peripheral ID Register[7:0] Can be used by software to identify the presence of this peripheral. 188 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 26: GPIO Peripheral Identification 1(GPIOPeriphID1), offset 0xFE4 The GPIOPeriphID0, GPIOPeriphID1, GPIOPeriphID2, and GPIOPeriphID3 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral. GPIO Peripheral Identification 1 (GPIOPeriphID1) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFE4 Type RO, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID1 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID1 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Peripheral ID Register[15:8] Can be used by software to identify the presence of this peripheral. June 14, 2007 189 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 27: GPIO Peripheral Identification 2 (GPIOPeriphID2), offset 0xFE8 The GPIOPeriphID0, GPIOPeriphID1, GPIOPeriphID2, and GPIOPeriphID3 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral. GPIO Peripheral Identification 2 (GPIOPeriphID2) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFE8 Type RO, reset 0x0x0000.0018 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 1 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID2 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID2 RO 0x18 RO 0 RO 0 RO 0 RO 0 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Peripheral ID Register[23:16] Can be used by software to identify the presence of this peripheral. 190 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 28: GPIO Peripheral Identification 3 (GPIOPeriphID3), offset 0xFEC The GPIOPeriphID0, GPIOPeriphID1, GPIOPeriphID2, and GPIOPeriphID3 registers can conceptually be treated as one 32-bit register; each register contains eight bits of the 32-bit register, used by software to identify the peripheral. GPIO Peripheral Identification 3 (GPIOPeriphID3) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFEC Type RO, reset 0x0x0000.0001 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID3 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID3 RO 0x01 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO Peripheral ID Register[31:24] Can be used by software to identify the presence of this peripheral. June 14, 2007 191 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 29: GPIO PrimeCell Identification 0 (GPIOPCellID0), offset 0xFF0 The GPIOPCellID0, GPIOPCellID1, GPIOPCellID2, and GPIOPCellID3 registers are four 8-bit wide registers, that can conceptually be treated as one 32-bit register. The register is used as a standard cross-peripheral identification system. GPIO PrimeCell Identification 0 (GPIOPCellID0) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFF0 Type RO, reset 0x0x0000.000D 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 1 RO 1 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID0 RO 0x0D RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO PrimeCell ID Register[7:0] Provides software a standard cross-peripheral identification system. 192 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 30: GPIO PrimeCell Identification 1 (GPIOPCellID1), offset 0xFF4 The GPIOPCellID0, GPIOPCellID1, GPIOPCellID2, and GPIOPCellID3 registers are four 8-bit wide registers, that can conceptually be treated as one 32-bit register. The register is used as a standard cross-peripheral identification system. GPIO PrimeCell Identification 1 (GPIOPCellID1) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFF4 Type RO, reset 0x0x0000.00F0 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID1 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID1 RO 0xF0 RO 0 RO 1 RO 1 RO 1 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO PrimeCell ID Register[15:8] Provides software a standard cross-peripheral identification system. June 14, 2007 193 Luminary Micro Confidential-Advance Product Information General-Purpose Input/Outputs (GPIOs) Register 31: GPIO PrimeCell Identification 2 (GPIOPCellID2), offset 0xFF8 The GPIOPCellID0, GPIOPCellID1, GPIOPCellID2, and GPIOPCellID3 registers are four 8-bit wide registers, that can conceptually be treated as one 32-bit register. The register is used as a standard cross-peripheral identification system. GPIO PrimeCell Identification 2 (GPIOPCellID2) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFF8 Type RO, reset 0x0x0000.0005 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 1 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID2 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID2 RO 0x05 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO PrimeCell ID Register[23:16] Provides software a standard cross-peripheral identification system. 194 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 32: GPIO PrimeCell Identification 3 (GPIOPCellID3), offset 0xFFC The GPIOPCellID0, GPIOPCellID1, GPIOPCellID2, and GPIOPCellID3 registers are four 8-bit wide registers, that can conceptually be treated as one 32-bit register. The register is used as a standard cross-peripheral identification system. GPIO PrimeCell Identification 3 (GPIOPCellID3) GPIO Port A base: 0x4000.4000 GPIO Port B base: 0x4000.5000 GPIO Port C base: 0x4000.6000 GPIO Port D base: 0x4000.7000 GPIO Port E base: 0x4002.4000 GPIO Port F base: 0x4002.5000 GPIO Port G base: 0x4002.6000 Offset 0xFFC Type RO, reset 0x0x0000.00B1 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CID3 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID3 RO 0xB1 RO 0 RO 1 RO 0 RO 1 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPIO PrimeCell ID Register[31:24] Provides software a standard cross-peripheral identification system. June 14, 2007 195 Luminary Micro Confidential-Advance Product Information General-Purpose Timers 10 General-Purpose Timers GPTM Programmable timers can be used to count or time external events that drive the Timer input pins. ® The Stellaris General-Purpose Timer Module (GPTM) contains four GPTM blocks (Timer0, Timer1, Timer 2, and Timer 3). Each GPTM block provides two 16-bit timer/counters (referred to as TimerA and TimerB) that can be configured to operate independently as timers or event counters, or configured to operate as one 32-bit timer or one 32-bit Real-Time Clock (RTC). Timers can also be used to trigger analog-to-digital (ADC) conversions. The trigger signals from all of the general-purpose timers are ORed together before reaching the ADC module, so only one timer should be used to trigger ADC events. Note: Timer2 is an internal timer and can only be used to generate internal interrupts or trigger ADC events. ® The General-Purpose Timer Module is one timing resource available on the Stellaris microcontrollers. Other timer resources include the System Timer (SysTick) (see “System Timer (SysTick)” on page 38). The following modes are supported: ■ 32-bit Timer modes – Programmable one-shot timer – Programmable periodic timer – Real-Time Clock using 32.768-KHz input clock – Software-controlled event stalling (excluding RTC mode) ■ 16-bit Timer modes – General-purpose timer function with an 8-bit prescaler (for one-shot and periodic modes only) – Programmable one-shot timer – Programmable periodic timer – Software-controlled event stalling ■ 16-bit Input Capture modes – Input edge count capture – Input edge time capture ■ 16-bit PWM mode – Simple PWM mode with software-programmable output inversion of the PWM signal 196 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 10.1 Block Diagram Figure 10-1. GPTM Module Block Diagram 0x0000 (Down Counter Modes) TimerA Control GPTMTAPMR TA Comparator GPTMTAPR Clock / Edge Detect GPTMTAMATCHR Interrupt / Config TimerA Interrupt GPTMCFG GPTMTAILR GPTMAR En GPTMCTL GPTMIMR TimerB Interrupt CCP (even) GPTMTAMR RTC Divider GPTMRIS GPTMMIS TimerB Control GPTMICR GPTMTBPMR GPTMTBR En Clock / Edge Detect GPTMTBPR GPTMTBMATCHR GPTMTBILR CCP (odd) TB Comparator GPTMTBMR 0x0000 (Down Counter Modes) System Clock 10.2 Functional Description The main components of each GPTM block are two free-running 16-bit up/down counters (referred to as TimerA and TimerB), two 16-bit match registers, two prescaler match registers, and two 16-bit load/initialization registers and their associated control functions. The exact functionality of each GPTM is controlled by software and configured through the register interface. Software configures the GPTM using the GPTM Configuration (GPTMCFG) register (see page 208), the GPTM TimerA Mode (GPTMTAMR) register (see page 209), and the GPTM TimerB Mode (GPTMTBMR) register (see page 210). When in one of the 32-bit modes, the timer can only act as a 32-bit timer. However, when configured in 16-bit mode, the GPTM can have its two 16-bit timers configured in any combination of the 16-bit modes. 10.2.1 GPTM Reset Conditions After reset has been applied to the GPTM module, the module is in an inactive state, and all control registers are cleared and in their default states. Counters TimerA and TimerB are initialized to 0xFFFF, along with their corresponding load registers: the GPTM TimerA Interval Load (GPTMTAILR) register (see page 219) and the GPTM TimerB Interval Load (GPTMTBILR) register (see page 220). The prescale counters are initialized to 0x00: the GPTM TimerA Prescale (GPTMTAPR) register (see page 223) and the GPTM TimerB Prescale (GPTMTBPR) register (see page 224). 10.2.2 32-Bit Timer Operating Modes Note: Both the odd- and even-numbered CCP pins are used for 16-bit mode. Only the even-numbered CCP pins are used for 32-bit mode. June 14, 2007 197 Luminary Micro Confidential-Advance Product Information General-Purpose Timers This section describes the three GPTM 32-bit timer modes (One-Shot, Periodic, and RTC) and their configuration. The GPTM is placed into 32-bit mode by writing a 0 (One-Shot/Periodic 32-bit timer mode) or a 1 (RTC mode) to the GPTM Configuration (GPTMCFG) register. In both configurations, certain GPTM registers are concatenated to form pseudo 32-bit registers. These registers include: ■ GPTM TimerA Interval Load (GPTMTAILR) register [15:0], see page 219 ■ GPTM TimerB Interval Load (GPTMTBILR) register [15:0], see page 220 ■ GPTM TimerA (GPTMTAR) register [15:0], see page 227 ■ GPTM TimerB (GPTMTBR) register [15:0], see page 228 In the 32-bit modes, the GPTM translates a 32-bit write access to GPTMTAILR into a write access to both GPTMTAILR and GPTMTBILR. The resulting word ordering for such a write operation is: GPTMTBILR[15:0]:GPTMTAILR[15:0] Likewise, a read access to GPTMTAR returns the value: GPTMTBR[15:0]:GPTMTAR[15:0] 10.2.2.1 32-Bit One-Shot/Periodic Timer Mode In 32-bit one-shot and periodic timer modes, the concatenated versions of the TimerA and TimerB registers are configured as a 32-bit down-counter. The selection of one-shot or periodic mode is determined by the value written to the TAMR field of the GPTM TimerA Mode (GPTMTAMR) register (see page 209), and there is no need to write to the GPTM TimerB Mode (GPTMTBMR) register. When software writes the TAEN bit in the GPTM Control (GPTMCTL) register (see page 211), the timer begins counting down from its preloaded value. Once the 0x0000.0000 state is reached, the timer reloads its start value from the concatenated GPTMTAILR on the next cycle. If configured to be a one-shot timer, the timer stops counting and clears the TAEN bit in the GPTMCTL register. If configured as a periodic timer, it continues counting. In addition to reloading the count value, the GPTM generates interrupts and output triggers when it reaches the 0x0000000 state. The GPTM sets the TATORIS bit in the GPTM Raw Interrupt Status (GPTMRIS) register (see page 215), and holds it until it is cleared by writing the GPTM Interrupt Clear (GPTMICR) register (see page 217). If the time-out interrupt is enabled in the GPTM Interrupt Mask (GPTIMR) register (see page 213), the GPTM also sets the TATOMIS bit in the GPTM Masked Interrupt Status (GPTMMIS) register (see page 216). The output trigger is a one-clock-cycle pulse that is asserted when the counter hits the 0x0000.0000 state, and deasserted on the following clock cycle. It is enabled by setting the TAOTE bit in GPTMCTL, and can trigger SoC-level events such as ADC conversions. If software reloads the GPTMTAILR register while the counter is running, the counter loads the new value on the next clock cycle and continues counting from the new value. If the TASTALL bit in the GPTMCTL register is asserted, the timer freezes counting until the signal is deasserted. 10.2.2.2 32-Bit Real-Time Clock Timer Mode In Real-Time Clock (RTC) mode, the concatenated versions of the TimerA and TimerB registers are configured as a 32-bit up-counter. When RTC mode is selected for the first time, the counter is 198 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller loaded with a value of 0x0000.0001. All subsequent load values must be written to the GPTM TimerA Match (GPTMTAMATCHR) register (see page 221) by the controller. The input clock on the CCP0, CCP2 or CCP4 pins is required to be 32.768 KHz in RTC mode. The clock signal is then divided down to a 1 Hz rate and is passed along to the input of the 32-bit counter. When software writes the TAEN bit inthe GPTMCTL register, the counter starts counting up from its preloaded value of 0x0000.0001. When the current count value matches the preloaded value in the GPTMTAMATCHR register, it rolls over to a value of 0x0000.0000 and continues counting until either a hardware reset, or it is disabled by software (clearing the TAEN bit). When a match occurs, the GPTM asserts the RTCRIS bit in GPTMRIS. If the RTC interrupt is enabled in GPTIMR, the GPTM also sets the RTCMIS bit in GPTMISR and generates a controller interrupt. The status flags are cleared by writing the RTCCINT bit in GPTMICR. If the TASTALL and/or TBSTALL bits in the GPTMCTL register are set, the timer does not freeze if the RTCEN bit is set in GPTMCTL. 10.2.3 16-Bit Timer Operating Modes The GPTM is placed into global 16-bit mode by writing a value of 0x4 to the GPTM Configuration (GPTMCFG) register (see page 208). This section describes each of the GPTM 16-bit modes of operation. TimerA and TimerB have identical modes, so a single description is given using an n to reference both. 10.2.3.1 16-Bit One-Shot/Periodic Timer Mode In 16-bit one-shot and periodic timer modes, the timer is configured as a 16-bit down-counter with an optional 8-bit prescaler that effectively extends the counting range of the timer to 24 bits. The selection of one-shot or periodic mode is determined by the value written to the TnMR field of the GPTMTnMR register. The optional prescaler is loaded into the GPTM Timern Prescale (GPTMTnPR) register. When software writes the TnEN bit in the GPTMCTL register, the timer begins counting down from its preloaded value. Once the 0x0000 state is reached, the timer reloads its start value from GPTMTnILR and GPTMTnPR on the next cycle. If configured to be a one-shot timer, the timer stops counting and clears the TnEN bit in the GPTMCTL register. If configured as a periodic timer, it continues counting. In addition to reloading the count value, the timer generates interrupts and output triggers when it reaches the 0x0000 state. The GPTM sets the TnTORIS bit in the GPTMRIS register, and holds it until it is cleared by writing the GPTMICR register. If the time-out interrupt is enabled in GPTIMR, the GPTM also sets the TnTOMIS bit in GPTMISR and generates a controller interrupt. The output trigger is a one-clock-cycle pulse that is asserted when the counter hits the 0x0000 state, and deasserted on the following clock cycle. It is enabled by setting the TnOTE bit in the GPTMCTL register, and can trigger SoC-level events such as ADC conversions. If software reloads the GPTMTAILR register while the counter is running, the counter loads the new value on the next clock cycle and continues counting from the new value. If the TnSTALL bit in the GPTMCTL register is enabled, the timer freezes counting until the signal is deasserted. The following example shows a variety of configurations for a 16-bit free running timer while using the prescaler. All values assume a 50-MHz clock with Tc=20 ns (clock period). June 14, 2007 199 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Table 10-1. 16-Bit Timer With Prescaler Configurations a Prescale #Clock (T c) Max Time Units 00000000 1 1.3107 mS 00000001 2 2.6214 mS 00000010 3 23.9321 mS ------------ -- -- -- 11111100 254 332.9229 mS 11111110 255 334.2336 mS 11111111 256 335.5443 mS a. Tc is the clock period. 10.2.3.2 16-Bit Input Edge Count Mode In Edge Count mode, the timer is configured as a down-counter capable of capturing three types of events: rising edge, falling edge, or both. To place the timer in Edge Count mode, the TnCMR bit of the GPTMTnMR register must be set to 0. The type of edge that the timer counts is determined by the TnEVENT fields of the GPTMCTL register. During initialization, the GPTM Timern Match (GPTMTnMATCHR) register is configured so that the difference between the value in the GPTMTnILR register and the GPTMTnMATCHR register equals the number of edge events that must be counted. When software writes the TnEN bit in the GPTM Control (GPTMCTL) register, the timer is enabled for event capture. Each input event on the CCP pin decrements the counter by 1 until the event count matches GPTMTnMATCHR. When the counts match, the GPTM asserts the CnMRIS bit in the GPTMRIS register (and the CnMMIS bit, if the interrupt is not masked). The counter is then reloaded using the value in GPTMTnILR, and stopped since the GPTM automatically clears the TnEN bit in the GPTMCTL register. Once the event count has been reached, all further events are ignored until TnEN is re-enabled by software. Figure 10-2 on page 201 shows how input edge count mode works. In this case, the timer start value is set to GPTMnILR =0x000A and the match value is set to GPTMnMATCHR =0x0006 so that four edge events are counted. The counter is configured to detect both edges of the input signal. Note that the last two edges are not counted since the timer automatically clears the TnEN bit after the current count matches the value in the GPTMnMR register. 200 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 10-2. 16-Bit Input Edge Count Mode Example Count Timer reload on next cycle Ignored Ignored 0x000A 0x0009 0x0008 0x0007 0x0006 Timer stops, flags asserted Input Signal 10.2.3.3 16-Bit Input Edge Time Mode Note: The prescaler is not available in 16-Bit Input Edge Time mode. In Edge Time mode, the timer is configured as a free-running down-counter initialized to the value loaded in the GPTMTnILR register (or 0xFFFF at reset). This mode allows for event capture of both rising and falling edges. The timer is placed into Edge Time mode by setting the TnCMR bit in the GPTMTnMR register, and the type of event that the timer captures is determined by the TnEVENT fields of the GPTMCnTL register. When software writes the TnEN bit in the GPTMCTL register, the timer is enabled for event capture. When the selected input event is detected, the current Tn counter value is captured in the GPTMTnR register and is available to be read by the controller. The GPTM then asserts the CnERIS bit (and the CnEMIS bit, if the interrupt is not masked). After an event has been captured, the timer does not stop counting. It continues to count until the TnEN bit is cleared. When the timer reaches the 0x0000 state, it is reloaded with the value from the GPTMnILR register. Figure 10-3 on page 202 shows how input edge timing mode works. In the diagram, it is assumed that the start value of the timer is the default value of 0xFFFF, and the timer is configured to capture rising edge events. Each time a rising edge event is detected, the current count value is loaded into the GPTMTnR register, and is held there until another rising edge is detected (at which point the new count value is loaded into GPTMTnR). June 14, 2007 201 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Figure 10-3. 16-Bit Input Edge Time Mode Example Count 0xFFFF GPTMTnR=X GPTMTnR=Y GPTMTnR=Z Z X Y Time Input Signal 10.2.3.4 16-Bit PWM Mode The GPTM supports a simple PWM generation mode. In PWM mode, the timer is configured as a down-counter with a start value (and thus period) defined by GPTMTnILR. PWM mode is enabled with the GPTMTnMR register by setting the TnAMS bit to 0x1, the TnCMR bit to 0x0, and the TnMR field to 0x2. When software writes the TnEN bit in the GPTMCTL register, the counter begins counting down until it reaches the 0x0000 state. On the next counter cycle, the counter reloads its start value from GPTMTnILR (and GPTMTnPR if using a prescaler) and continues counting until disabled by software clearing the TnEN bit in the GPTMCTL register. No interrupts or status bits are asserted in PWM mode. The output PWM signal asserts when the counter is at the value of the GPTMTnILR register (its start state), and is deasserted when the counter value equals the value in the GPTM Timern Match Register (GPTMnMATCHR). Software has the capability of inverting the output PWM signal by setting the TnPWML bit in the GPTMCTL register. Figure 10-4 on page 203 shows how to generate an output PWM with a 1-ms period and a 66% duty cycle assuming a 50-MHz input clock and TnPWML =0 (duty cycle would be 33% for the TnPWML =1 configuration). For this example, the start value is GPTMnIRL=0xC350 and the match value is GPTMnMR=0x411A. 202 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 10-4. 16-Bit PWM Mode Example Count GPTMTnR=GPTMnMR GPTMTnR=GPTMnMR 0xC350 0x411A Time TnEN set TnPWML = 0 Output Signal TnPWML = 1 10.3 Initialization and Configuration To use the general-purpose timers, the peripheral clock must be enabled by setting the TIMER0, TIMER1, TIMER2, and TIMER3 bits in the RCGC1 register. This section shows module initialization and configuration examples for each of the supported timer modes. 10.3.1 32-Bit One-Shot/Periodic Timer Mode The GPTM is configured for 32-bit One-Shot and Periodic modes by the following sequence: 1. Ensure the timer is disabled (the TAEN bit in the GPTMCTL register is cleared) before making any changes. 2. Write the GPTM Configuration Register (GPTMCFG) with a value of 0x0. 3. Set the TAMR field in the GPTM TimerA Mode Register (GPTMTAMR): a. Write a value of 0x1 for One-Shot mode. b. Write a value of 0x2 for Periodic mode. 4. Load the start value into the GPTM TimerA Interval Load Register (GPTMTAILR). 5. If interrupts are required, set the TATOIM bit in the GPTM Interrupt Mask Register (GPTMIMR). 6. Set the TAEN bit in the GPTMCTL register to enable the timer and start counting. June 14, 2007 203 Luminary Micro Confidential-Advance Product Information General-Purpose Timers 7. Poll the TATORIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases, the status flags are cleared by writing a 1 to the TATOCINT bit of the GPTM Interrupt Clear Register (GPTMICR). In One-Shot mode, the timer stops counting after 7 on page 204. To re-enable the timer, repeat the sequence. A timer configured in Periodic mode does not stop counting after it times out. 10.3.2 32-Bit Real-Time Clock (RTC) Mode To use the RTC mode, the timer must have a 32.768-KHz input signal on its CCP0, CCP2 or CCP4 pins. To enable the RTC feature, follow these steps: 1. Ensure the timer is disabled (the TAEN bit is cleared) before making any changes. 2. Write the GPTM Configuration Register (GPTMCFG) with a value of 0x1. 3. Write the desired match value to the GPTM TimerA Match Register (GPTMTAMATCHR). 4. Set/clear the RTCEN bit in the GPTM Control Register (GPTMCTL) as desired. 5. If interrupts are required, set the RTCIM bit in the GPTM Interrupt Mask Register (GPTMIMR). 6. Set the TAEN bit in the GPTMCTL register to enable the timer and start counting. When the timer count equals the value in the GPTMTAMATCHR register, the counter is re-loaded with 0x0000.0000 and begins counting. If an interrupt is enabled, it does not have to be cleared. 10.3.3 16-Bit One-Shot/Periodic Timer Mode A timer is configured for 16-bit One-Shot and Periodic modes by the following sequence: 1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes. 2. Write the GPTM Configuration Register (GPTMCFG) with a value of 0x4. 3. Set the TnMR field in the GPTM Timer Mode (GPTMTnMR) register: a. Write a value of 0x1 for One-Shot mode. b. Write a value of 0x2 for Periodic mode. 4. If a prescaler is to be used, write the prescale value to the GPTM Timern Prescale Register (GPTMTnPR). 5. Load the start value into the GPTM Timer Interval Load Register (GPTMTnILR). 6. If interrupts are required, set the TnTOIM bit in the GPTM Interrupt Mask Register (GPTMIMR). 7. Set the TnEN bit in the GPTM Control Register (GPTMCTL) to enable the timer and start counting. 8. Poll the TnTORIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases, the status flags are cleared by writing a 1 to the TnTOCINT bit of the GPTM Interrupt Clear Register (GPTMICR). 204 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller In One-Shot mode, the timer stops counting after 8 on page 204. To re-enable the timer, repeat the sequence. A timer configured in Periodic mode does not stop counting after it times out. 10.3.4 16-Bit Input Edge Count Mode A timer is configured to Input Edge Count mode by the following sequence: 1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes. 2. Write the GPTM Configuration (GPTMCFG) register with a value of 0x4. 3. In the GPTM Timer Mode (GPTMTnMR) register, write the TnCMR field to 0x0 and the TnMR field to 0x3. 4. Configure the type of event(s) that the timer captures by writing the TnEVENT field of the GPTM Control (GPTMCTL) register. 5. Load the timer start value into the GPTM Timern Interval Load (GPTMTnILR) register. 6. Load the desired event count into the GPTM Timern Match (GPTMTnMATCHR) register. 7. If interrupts are required, set the CnMIM bit in the GPTM Interrupt Mask (GPTMIMR) register. 8. Set the TnEN bit in the GPTMCTL register to enable the timer and begin waiting for edge events. 9. Poll the CnMRIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases, the status flags are cleared by writing a 1 to the CnMCINT bit of the GPTM Interrupt Clear (GPTMICR) register. In Input Edge Count Mode, the timer stops after the desired number of edge events has been detected. To re-enable the timer, ensure that the TnEN bit is cleared and repeat steps 4 on page 205-9 on page 205. 10.3.5 16-Bit Input Edge Timing Mode A timer is configured to Input Edge Timing mode by the following sequence: 1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes. 2. Write the GPTM Configuration (GPTMCFG) register with a value of 0x4. 3. In the GPTM Timer Mode (GPTMTnMR) register, write the TnCMR field to 0x1 and the TnMR field to 0x3. 4. Configure the type of event that the timer captures by writing the TnEVENT field of the GPTM Control (GPTMCTL) register. 5. Load the timer start value into the GPTM Timern Interval Load (GPTMTnILR) register. 6. If interrupts are required, set the CnEIM bit in the GPTM Interrupt Mask (GPTMIMR) register. 7. Set the TnEN bit in the GPTM Control (GPTMCTL) register to enable the timer and start counting. 8. Poll the CnERIS bit in the GPTMRIS register or wait for the interrupt to be generated (if enabled). In both cases, the status flags are cleared by writing a 1 to the CnECINT bit of the GPTM June 14, 2007 205 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Interrupt Clear (GPTMICR) register. The time at which the event happened can be obtained by reading the GPTM Timern (GPTMTnR) register. In Input Edge Timing mode, the timer continues running after an edge event has been detected, but the timer interval can be changed at any time by writing the GPTMTnILR register. The change takes effect at the next cycle after the write. 10.3.6 16-Bit PWM Mode A timer is configured to PWM mode using the following sequence: 1. Ensure the timer is disabled (the TnEN bit is cleared) before making any changes. 2. Write the GPTM Configuration (GPTMCFG) register with a value of 0x4. 3. In the GPTM Timer Mode (GPTMTnMR) register, set the TnAMS bit to 0x1, the TnCMR bit to 0x0, and the TnMR field to 0x2. 4. Configure the output state of the PWM signal (whether or not it is inverted) in the TnEVENT field of the GPTM Control (GPTMCTL) register. 5. Load the timer start value into the GPTM Timern Interval Load (GPTMTnILR) register. 6. Load the GPTM Timern Match (GPTMTnMATCHR) register with the desired value. 7. Set the TnEN bit in the GPTM Control (GPTMCTL) register to enable the timer and begin generation of the output PWM signal. In PWM Timing mode, the timer continues running after the PWM signal has been generated. The PWM period can be adjusted at any time by writing the GPTMTnILR register, and the change takes effect at the next cycle after the write. 10.4 Register Map Table 10-2 on page 206 lists the GPTM registers. The offset listed is a hexadecimal increment to the register’s address, relative to that timer’s base address: ■ Timer0: 0x4003.0000 0x4003.0000 ■ Timer1: 0x4003.1000 0x4003.1000 ■ Timer2: 0x4003.2000 0x4003.2000 ■ Timer3: 0x4003.3000 0x4003.3000 Table 10-2. Timers Register Map Description See page Offset Name Type Reset 0x000 GPTMCFG R/W 0x0x0000.0000 GPTM Configuration 208 0x004 GPTMTAMR R/W 0x0x0000.0000 GPTM TimerA Mode 209 0x008 GPTMTBMR R/W 0x0x0000.0000 GPTM TimerB Mode 210 0x00C GPTMCTL R/W 0x0x0000.0000 GPTM Control 211 206 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Description See page Offset Name Type Reset 0x018 GPTMIMR R/W 0x0x0000.0000 GPTM Interrupt Mask 213 0x01C GPTMRIS RO 0x0x0000.0000 GPTM Raw Interrupt Status 215 0x020 GPTMMIS RO 0x0x0000.0000 GPTM Masked Interrupt Status 216 0x024 GPTMICR W1C 0x0x0000.0000 GPTM Interrupt Clear 217 0x028 GPTMTAILR R/W 0x0000.FFFF (16-bit mode) 0xFFFF.FFFF (32-bit mode) GPTM TimerA Interval Load 219 0x02C GPTMTBILR R/W 0x0000.FFFF GPTM TimerB Interval Load 220 GPTM TimerA Match 221 0x030 GPTMTAMATCHR R/W 0x0000.FFFF (16-bit mode) 0xFFFF.FFFF (32-bit mode) 0x034 GPTMTBMATCHR R/W 0x0000.FFFF GPTM TimerB Match 222 0x038 GPTMTAPR R/W 0x0000.0000 GPTM TimerA Prescale 223 0x03C GPTMTBPR R/W 0x0000.0000 GPTM TimerB Prescale 224 0x040 GPTMTAPMR R/W 0x0000.0000 GPTM TimerA Prescale Match 225 0x044 GPTMTBPMR R/W 0x0000.0000 GPTM TimerB Prescale Match 226 0x048 GPTMTAR RO 0x0000.FFFF (16-bit mode) 0xFFFF.FFFF (32-bit mode) GPTM TimerA 227 0x04C GPTMTBR RO 0x0000.FFFF GPTM TimerB 228 10.5 Register Descriptions The remainder of this section lists and describes the GPTM registers, in numerical order by address offset. June 14, 2007 207 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Register 1: GPTM Configuration (GPTMCFG), offset 0x000 This register configures the global operation of the GPTM module. The value written to this register determines whether the GPTM is in 32- or 16-bit mode. GPTM Configuration (GPTMCFG) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x000 Type R/W, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 GPTMCFG RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2:0 GPTMCFG R/W 0 GPTM Configuration 0x0: 32-bit timer configuration. 0x1: 32-bit real-time clock (RTC) counter configuration. 0x2: Reserved. 0x3: Reserved. 0x4-0x7: 16-bit timer configuration, function is controlled by bits 1:0 of GPTMTAMR and GPTMTBMR. 208 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: GPTM TimerA Mode (GPTMTAMR), offset 0x004 This register configures the GPTM based on the configuration selected in the GPTMCFG register. When in 16-bit PWM mode, set the TAAMS bit to 0x1, the TACMR bit to 0x0, and the TAMR field to 0x2. GPTM TimerA Mode (GPTMTAMR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x004 Type R/W, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 TAAMS TACMR R/W 0 R/W 0 0 TAMR R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TAAMS R/W 0 GPTM TimerA Alternate Mode Select 0: Capture mode is enabled. 1: PWM mode is enabled. Note: 2 TACMR R/W 0 To enable PWM mode, you must also clear the TACMR bit and set the TAMR field to 0x2. GPTM TimerA Capture Mode 0: Edge-Count mode. 1: Edge-Time mode. 1:0 TAMR R/W 0 GPTM TimerA Mode 0x0: Reserved. 0x1: One-Shot Timer mode. 0x2: Periodic Timer mode. 0x3: Capture mode. The Timer mode is based on the timer configuration defined by bits 2:0 in the GPTMCFG register (16-or 32-bit). In 16-bit timer configuration, TAMR controls the 16-bit timer modes for TimerA. In 32-bit timer configuration, this register controls the mode and the contents of GPTMTBMR are ignored. June 14, 2007 209 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Register 3: GPTM TimerB Mode (GPTMTBMR), offset 0x008 This register configures the GPTM based on the configuration selected in the GPTMCFG register. When in 16-bit PWM mode, set the TBAMS bit to 0x1, the TBCMR bit to 0x0, and the TBMR field to 0x2. GPTM TimerB Mode (GPTMTBMR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x008 Type R/W, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 TBAMS TBCMR R/W 0 R/W 0 0 TBMR R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TBAMS R/W 0 GPTM TimerB Alternate Mode Select 0: Capture mode is enabled. 1: PWM mode is enabled. Note: 2 TBCMR R/W 0 To enable PWM mode, you must also clear the TBCMR bit and set the TBMR field to 0x2. GPTM TimerB Capture Mode 0: Edge-Count mode. 1: Edge-Time mode. 1:0 TBMR R/W 0 GPTM TimerB Mode 0x0: Reserved. 0x1: One-Shot Timer mode. 0x2: Periodic Timer mode. 0x3: Capture mode. The timer mode is based on the timer configuration defined by bits 2:0 in the GPTMCFG register. In 16-bit timer configuration, these bits control the 16-bit timer modes for TimerB. In 32-bit timer configuration, this register’s contents are ignored and GPTMTAMR is used. 210 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 4: GPTM Control (GPTMCTL), offset 0x00C This register is used alongside the GPTMCFG and GMTMTnMR registers to fine-tune the timer configuration, and to enable other features such as timer stall and the output trigger. The output trigger can be used to initiate transfers on the ADC module. GPTM Control (GPTMCTL) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x00C Type R/W, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 3 2 reserved Type Reset RO 0 RO 0 RO 0 15 14 13 reserved TBPWML TBOTE Type Reset RO 0 R/W 0 RO 0 RO 0 RO 0 12 11 10 reserved R/W 0 RO 0 TBEVENT R/W 0 R/W 0 RO 0 RO 0 9 8 TBSTALL TBEN R/W 0 R/W 0 reserved TAPWML RO 0 R/W 0 5 4 TAOTE RTCEN R/W 0 R/W 0 TAEVENT R/W 0 R/W 0 1 0 TASTALL TAEN R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14 TBPWML R/W 0 GPTM TimerB PWM Output Level 0: Output is unaffected. 1: Output is inverted. 13 TBOTE R/W 0 GPTM TimerB Output Trigger Enable 0: The output TimerB trigger is disabled. 1: The output TimerB trigger is enabled. 12 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 11:10 TBEVENT R/W 0 GPTM TimerB Event Mode 00: Positive edge. 01: Negative edge. 10: Reserved. 11: Both edges. 9 TBSTALL R/W 0 GPTM TimerB Stall Enable 0: TimerB stalling is disabled. 1: TimerB stalling is enabled. June 14, 2007 211 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Bit/Field Name Type Reset 8 TBEN R/W 0 Description GPTM TimerB Enable 0: TimerB is disabled. 1: TimerB is enabled and begins counting or the capture logic is enabled based on the GPTMCFG register. 7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 TAPWML R/W 0 GPTM TimerA PWM Output Level 0: Output is unaffected. 1: Output is inverted. 5 TAOTE R/W 0 GPTM TimerA Output Trigger Enable 0: The output TimerA trigger is disabled. 1: The output TimerA trigger is enabled. 4 RTCEN R/W 0 GPTM RTC Enable 0: RTC counting is disabled. 1: RTC counting is enabled. 3:2 TAEVENT R/W 0 GPTM TimerA Event Mode 00: Positive edge. 01: Negative edge. 10: Reserved. 11: Both edges. 1 TASTALL R/W 0 GPTM TimerA Stall Enable 0: TimerA stalling is disabled. 1: TimerA stalling is enabled. 0 TAEN R/W 0 GPTM TimerA Enable 0: TimerA is disabled. 1: TimerA is enabled and begins counting or the capture logic is enabled based on the GPTMCFG register. 212 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 5: GPTM Interrupt Mask (GPTMIMR), offset 0x018 This register allows software to enable/disable GPTM controller-level interrupts. Writing a 1 enables the interrupt, while writing a 0 disables it. GPTM Interrupt Mask (GPTMIMR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x018 Type R/W, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 15 14 RO 0 RO 0 RO 0 13 12 11 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 10 9 8 CBEIM CBMIM TBTOIM R/W 0 R/W 0 R/W 0 reserved RO 0 RO 0 RO 0 RO 0 3 2 1 0 RTCIM CAEIM CAMIM TATOIM R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 CBEIM R/W 0 GPTM CaptureB Event Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled. 9 CBMIM R/W 0 GPTM CaptureB Match Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled. 8 TBTOIM R/W 0 GPTM TimerB Time-Out Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled. 7:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 RTCIM R/W 0 GPTM RTC Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled. 2 CAEIM R/W 0 GPTM CaptureA Event Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled. June 14, 2007 213 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Bit/Field Name Type Reset 1 CAMIM R/W 0 Description GPTM CaptureA Match Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled. 0 TATOIM R/W 0 GPTM TimerA Time-Out Interrupt Mask 0: Interrupt is disabled. 1: Interrupt is enabled. 214 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: GPTM Raw Interrupt Status (GPTMRIS), offset 0x01C This register shows the state of the GPTM's internal interrupt signal. These bits are set whether or not the interrupt is masked in the GPTMIMR register. Each bit can be cleared by writing a 1 to its corresponding bit in GPTMICR. GPTM Raw Interrupt Status (GPTMRIS) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x01C Type RO, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 2 1 0 reserved Type Reset RO 0 RO 0 15 14 RO 0 RO 0 RO 0 13 12 11 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 4 CBERIS CBMRIS TBTORIS RO 0 RO 0 RO 0 RO 0 RO 0 reserved RO 0 RO 0 RO 0 3 RTCRIS RO 0 RO 0 CAERIS CAMRIS TATORIS RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 CBERIS RO 0 GPTM CaptureB Event Raw Interrupt This is the CaptureB Event interrupt status prior to masking. 9 CBMRIS RO 0 GPTM CaptureB Match Raw Interrupt This is the CaptureB Match interrupt status prior to masking. 8 TBTORIS RO 0 GPTM TimerB Time-Out Raw Interrupt This is the TimerB time-out interrupt status prior to masking. 7:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 RTCRIS RO 0 GPTM RTC Raw Interrupt This is the RTC Event interrupt status prior to masking. 2 CAERIS RO 0 GPTM CaptureA Event Raw Interrupt This is the CaptureA Event interrupt status prior to masking. 1 CAMRIS RO 0 GPTM CaptureA Match Raw Interrupt This is the CaptureA Match interrupt status prior to masking. 0 TATORIS RO 0 GPTM TimerA Time-Out Raw Interrupt This the TimerA time-out interrupt status prior to masking. June 14, 2007 215 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Register 7: GPTM Masked Interrupt Status (GPTMMIS), offset 0x020 This register show the state of the GPTM's controller-level interrupt. If an interrupt is unmasked in GPTMIMR, and there is an event that causes the interrupt to be asserted, the corresponding bit is set in this register. All bits are cleared by writing a 1 to the corresponding bit in GPTMICR. GPTM Masked Interrupt Status (GPTMMIS) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x020 Type RO, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 reserved Type Reset RO 0 RO 0 15 14 RO 0 RO 0 RO 0 13 12 11 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 4 CBEMIS CBMMIS TBTOMIS RO 0 RO 0 RO 0 RO 0 RO 0 reserved RO 0 RO 0 RO 0 RTCMIS CAEMIS CAMMIS TATOMIS RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 CBEMIS RO 0 GPTM CaptureB Event Masked Interrupt This is the CaptureB event interrupt status after masking. 9 CBMMIS RO 0 GPTM CaptureB Match Masked Interrupt This is the CaptureB match interrupt status after masking. 8 TBTOMIS RO 0 GPTM TimerB Time-Out Masked Interrupt This is the TimerB time-out interrupt status after masking. 7:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 RTCMIS RO 0 GPTM RTC Masked Interrupt This is the RTC event interrupt status after masking. 2 CAEMIS RO 0 GPTM CaptureA Event Masked Interrupt This is the CaptureA event interrupt status after masking. 1 CAMMIS RO 0 GPTM CaptureA Match Masked Interrupt This is the CaptureA match interrupt status after masking. 0 TATOMIS RO 0 GPTM TimerA Time-Out Masked Interrupt This is the TimerA time-out interrupt status after masking. 216 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 8: GPTM Interrupt Clear (GPTMICR), offset 0x024 This register is used to clear the status bits in the GPTMRIS and GPTMMIS registers. Writing a 1 to a bit clears the corresponding bit in the GPTMRIS and GPTMMIS registers. GPTM Interrupt Clear (GPTMICR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x024 Type W1C, reset 0x0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 reserved Type Reset RO 0 RO 0 15 14 RO 0 RO 0 RO 0 13 12 11 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 4 CBECINT CBMCINT TBTOCINT RO 0 RO 0 RO 0 W1C 0 W1C 0 W1C 0 reserved RO 0 RO 0 RO 0 RTCCINT CAECINT CAMCINT TATOCINT RO 0 W1C 0 W1C 0 W1C 0 W1C 0 Bit/Field Name Type Reset Description 31:11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 CBECINT W1C 0 GPTM CaptureB Event Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared. 9 CBMCINT W1C 0 GPTM CaptureB Match Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared. 8 TBTOCINT W1C 0 GPTM TimerB Time-Out Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared. 7:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 RTCCINT W1C 0 GPTM RTC Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared. 2 CAECINT W1C 0 GPTM CaptureA Event Interrupt Clear 0: The interrupt is unaffected. 1: The interrupt is cleared. 1 CAMCINT W1C 0 GPTM CaptureA Match Raw Interrupt This is the CaptureA match interrupt status after masking. June 14, 2007 217 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Bit/Field Name Type Reset 0 TATOCINT W1C 0 Description GPTM TimerA Time-Out Raw Interrupt 0: The interrupt is unaffected. 1: The interrupt is cleared. 218 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 9: GPTM TimerA Interval Load (GPTMTAILR), offset 0x028 This register is used to load the starting count value into the timer. When GPTM is configured to one of the 32-bit modes, GPTMTAILR appears as a 32-bit register (the upper 16-bits correspond to the contents of the GPTM TimerB Interval Load (GPTMTBILR) register). In 16-bit mode, the upper 16 bits of this register read as 0s and have no effect on the state of GPTMTBILR. GPTM TimerA Interval Load (GPTMTAILR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x028 Type R/W, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode) 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 TAILRH Type Reset R/W 0 R/W 1 R/W 1 R/W 0 R/W 1 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 TAILRL Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type 31:16 TAILRH R/W R/W 1 R/W 1 Reset R/W 1 Description 0xFFFF GPTM TimerA Interval Load Register High (32-bit mode) 0x0000 (16-bit When configured for 32-bit mode via the GPTMCFG register, the GPTM TimerB Interval Load (GPTMTBILR) register loads this value on a mode) write. A read returns the current value of GPTMTBILR. In 16-bit mode, this field reads as 0 and does not have an effect on the state of GPTMTBILR. 15:0 TAILRL R/W 0xFFFF GPTM TimerA Interval Load Register Low For both 16- and 32-bit modes, writing this field loads the counter for TimerA. A read returns the current value of GPTMTAILR. June 14, 2007 219 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Register 10: GPTM TimerB Interval Load (GPTMTBILR), offset 0x02C This register is used to load the starting count value into TimerB. When the GPTM is configured to a 32-bit mode, GPTMTBILR returns the current value of TimerB and ignores writes. GPTM TimerB Interval Load (GPTMTBILR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x02C Type R/W, reset 0x0000.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 TBILRL Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type Reset 31:16 reserved RO 0 15:0 TBILRL R/W 0xFFFF R/W 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPTM TimerB Interval Load Register When the GPTM is not configured as a 32-bit timer, a write to this field updates GPTMTBILR. In 32-bit mode, writes are ignored, and reads return the current value of GPTMTBILR. 220 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 11: GPTM TimerA Match (GPTMTAMATCHR), offset 0x030 This register is used in 32-bit Real-Time Clock mode and 16-bit PWM and Input Edge Count modes. GPTM TimerA Match (GPTMTAMATCHR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x030 Type R/W, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode) 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 TAMRH Type Reset R/W 0 R/W 1 R/W 1 R/W 0 R/W 1 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 TAMRL Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type 31:16 TAMRH R/W R/W 1 R/W 1 Reset R/W 1 Description 0xFFFF GPTM TimerA Match Register High (32-bit mode) 0x0000 (16-bit When configured for 32-bit Real-Time Clock (RTC) mode via the GPTMCFG register, this value is compared to the upper half of mode) GPTMTAR, to determine match events. In 16-bit mode, this field reads as 0 and does not have an effect on the state of GPTMTBMATCHR. 15:0 TAMRL R/W 0xFFFF GPTM TimerA Match Register Low When configured for 32-bit Real-Time Clock (RTC) mode via the GPTMCFG register, this value is compared to the lower half of GPTMTAR, to determine match events. When configured for PWM mode, this value along with GPTMTAILR, determines the duty cycle of the output PWM signal. When configured for Edge Count mode, this value along with GPTMTAILR, determines how many edge events are counted. The total number of edge events counted is equal to the value in GPTMTAILR minus this value. June 14, 2007 221 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Register 12: GPTM TimerB Match (GPTMTBMATCHR), offset 0x034 This register is used in 32-bit Real-Time Clock mode and 16-bit PWM and Input Edge Count modes. GPTM TimerB Match (GPTMTBMATCHR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x034 Type R/W, reset 0x0000.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 TBMRL Type Reset R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 Bit/Field Name Type Reset 31:16 reserved RO 0 15:0 TBMRL R/W 0xFFFF R/W 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPTM TimerB Match Register Low When configured for PWM mode, this value along with GPTMTBILR, determines the duty cycle of the output PWM signal. When configured for Edge Count mode, this value along with GPTMTBILR, determines how many edge events are counted. The total number of edge events counted is equal to the value in GPTMTBILR minus this value. 222 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 13: GPTM TimerA Prescale (GPTMTAPR), offset 0x038 This register allows software to extend the range of the 16-bit timers when operating in one-shot or periodic mode. GPTM TimerA Prescale (GPTMTAPR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x038 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 TAPSR RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 TAPSR R/W 0 GPTM TimerA Prescale The register loads this value on a write. A read returns the current value of the register. Refer to Table 10-1 on page 200 for more details and an example. June 14, 2007 223 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Register 14: GPTM TimerB Prescale (GPTMTBPR), offset 0x03C This register allows software to extend the range of the 16-bit timers when operating in one-shot or periodic mode. GPTM TimerB Prescale (GPTMTBPR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x03C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 TBPSR RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 TBPSR R/W 0 GPTM TimerB Prescale The register loads this value on a write. A read returns the current value of this register. Refer to Table 10-1 on page 200 for more details and an example. 224 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 15: GPTM TimerA Prescale Match (GPTMTAPMR), offset 0x040 This register effectively extends the range of GPTMTAMATCHR to 24 bits when operating in 16-bit one-shot or periodic mode. GPTM TimerA Prescale Match (GPTMTAPMR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x040 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 TAPSMR RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 TAPSMR R/W 0 GPTM TimerA Prescale Match This value is used alongside GPTMTAMATCHR to detect timer match events while using a prescaler. June 14, 2007 225 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Register 16: GPTM TimerB Prescale Match (GPTMTBPMR), offset 0x044 This register effectively extends the range of GPTMTBMATCHR to 24 bits when operating in 16-bit one-shot or periodic mode. GPTM TimerB Prescale Match (GPTMTBPMR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x044 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 TBPSMR RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 TBPSMR R/W 0 GPTM TimerB Prescale Match This value is used alongside GPTMTBMATCHR to detect timer match events while using a prescaler. 226 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 17: GPTM TimerA (GPTMTAR), offset 0x048 This register shows the current value of the TimerA counter in all cases except for Input Edge Count mode. When in this mode, this register contains the time at which the last edge event took place. GPTM TimerA (GPTMTAR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x048 Type RO, reset 0x0000.FFFF (16-bit mode) and 0xFFFF.FFFF (32-bit mode) 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 1 RO 1 RO 0 RO 1 RO 1 RO 1 RO 1 RO 0 7 6 5 4 3 2 1 0 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 TARH Type Reset RO 0 RO 1 RO 1 RO 0 RO 1 RO 0 RO 1 RO 1 15 14 13 12 11 10 9 8 TARL Type Reset RO 1 RO 1 RO 1 RO 1 RO 1 Bit/Field Name Type 31:16 TARH RO 15:0 TARL RO RO 1 RO 1 Reset RO 1 Description 0xFFFF GPTM TimerA Register High (32-bit mode) 0x0000 (16-bit If the GPTMCFG is in a 32-bit mode, TimerB value is read. If the GPTMCFG is in a 16-bit mode, this is read as zero. mode) 0xFFFF GPTM TimerA Register Low A read returns the current value of the GPTM TimerA Count Register, except in Input Edge Count mode, when it returns the timestamp from the last edge event. June 14, 2007 227 Luminary Micro Confidential-Advance Product Information General-Purpose Timers Register 18: GPTM TimerB (GPTMTBR), offset 0x04C This register shows the current value of the TimerB counter in all cases except for Input Edge Count mode. When in this mode, this register contains the time at which the last edge event took place. GPTM TimerB (GPTMTBR) Timer0 base: 0x4003.0000 Timer1 base: 0x4003.1000 Timer2 base: 0x4003.2000 Timer3 base: 0x4003.3000 Offset 0x04C Type RO, reset 0x0000.FFFF 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 TBRL Type Reset RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 Bit/Field Name Type Reset 31:16 reserved RO 0 15:0 TBRL RO 0xFFFF RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. GPTM TimerB A read returns the current value of the GPTM TimerB Count Register, except in Input Edge Count mode, when it returns the timestamp from the last edge event. 228 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 11 Watchdog Timer WDT A watchdog timer can generate nonmaskable interrupts (NMIs) or a reset when a time-out value is reached. The watchdog timer is used to regain control when a system has failed due to a software error or due to the failure of an external device to respond in the expected way. ® The Stellaris Watchdog Timer module consists of a 32-bit down counter, a programmable load register, interrupt generation logic, a locking register, and user-enabled stalling. The Watchdog Timer can be configured to generate an interrupt to the controller on its first time-out, and to generate a reset signal on its second time-out. Once the Watchdog Timer has been configured, the lock register can be written to prevent the timer configuration from being inadvertently altered. 11.1 Block Diagram Figure 11-1. WDT Module Block Diagram WDTLOAD Control / Clock / Interrupt Generation WDTCTL WDTICR Interrupt WDTRIS 32-Bit Down Counter WDTMIS 0x00000000 WDTLOCK System Clock WDTTEST Comparator WDTVALUE Identification Registers 11.2 WDTPCellID0 WDTPeriphID0 WDTPeriphID4 WDTPCellID1 WDTPeriphID1 WDTPeriphID5 WDTPCellID2 WDTPeriphID2 WDTPeriphID6 WDTPCellID3 WDTPeriphID3 WDTPeriphID7 Functional Description The Watchdog Timer module consists of a 32-bit down counter, a programmable load register, interrupt generation logic, and a locking register. Once the Watchdog Timer has been configured, June 14, 2007 229 Luminary Micro Confidential-Advance Product Information Watchdog Timer the Watchdog Timer Lock (WDTLOCK) register is written, which prevents the timer configuration from being inadvertently altered by software. The Watchdog Timer module generates the first time-out signal when the 32-bit counter reaches the zero state after being enabled; enabling the counter also enables the watchdog timer interrupt. After the first time-out event, the 32-bit counter is re-loaded with the value of the Watchdog Timer Load (WDTLOAD) register, and the timer resumes counting down from that value. If the timer counts down to its zero state again before the first time-out interrupt is cleared, and the reset signal has been enabled (via the WatchdogResetEnable function), the Watchdog timer asserts its reset signal to the system. If the interrupt is cleared before the 32-bit counter reaches its second time-out, the 32-bit counter is loaded with the value in the WDTLOAD register, and counting resumes from that value. If WDTLOAD is written with a new value while the Watchdog Timer counter is counting, then the counter is loaded with the new value and continues counting. Writing to WDTLOAD does not clear an active interrupt. An interrupt must be specifically cleared by writing to the Watchdog Interrupt Clear (WDTICR) register. The Watchdog module interrupt and reset generation can be enabled or disabled as required. When the interrupt is re-enabled, the 32-bit counter is preloaded with the load register value and not its last state. 11.3 Initialization and Configuration To use the WDT, its peripheral clock must be enabled by setting the WDT bit in the RCGC0 register. The Watchdog Timer is configured using the following sequence: 1. Load the WDTLOAD register with the desired timer load value. 2. If the Watchdog is configured to trigger system resets, set the RESEN bit in the WDTCTL register. 3. Set the INTEN bit in the WDTCTL register to enable the Watchdog and lock the control register. If software requires that all of the watchdog registers are locked, the Watchdog Timer module can be fully locked by writing any value to the WDTLOCK register. To unlock the Watchdog Timer, write a value of 0x1ACCE551. 11.4 Register Map Table 11-1 on page 230 lists the Watchdog registers. The offset listed is a hexadecimal increment to the register’s address, relative to the Watchdog Timer base address of 0x4000.0000. Table 11-1. Watchdog Timer Register Map Description See page Offset Name Type Reset 0x000 WDTLOAD R/W 0xFFFF.FFFF Watchdog Load 232 0x004 WDTVALUE RO 0xFFFF.FFFF Watchdog Value 233 0x008 WDTCTL R/W 0x0000.0000 Watchdog Control 234 0x00C WDTICR WO - Watchdog Interrupt Clear 235 0x010 WDTRIS RO 0x0000.0000 Watchdog Raw Interrupt Status 236 230 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Offset Name 0x014 Reset WDTMIS RO 0x0000.0000 Watchdog Masked Interrupt Status 237 0x418 WDTTEST R/W 0x0000.0000 Watchdog Test 238 0xC00 WDTLOCK R/W 0x0000.0000 Watchdog Lock 239 0xFD0 WDTPeriphID4 RO 0x0000.0000 Watchdog Peripheral Identification 4 240 0xFD4 WDTPeriphID5 RO 0x0000.0000 Watchdog Peripheral Identification 5 241 0xFD8 WDTPeriphID6 RO 0x0000.0000 Watchdog Peripheral Identification 6 242 0xFDC WDTPeriphID7 RO 0x0000.0000 Watchdog Peripheral Identification 7 243 0xFE0 WDTPeriphID0 RO 0x0000.0005 Watchdog Peripheral Identification 0 244 0xFE4 WDTPeriphID1 RO 0x0000.0018 Watchdog Peripheral Identification 1 245 0xFE8 WDTPeriphID2 RO 0x0000.0018 Watchdog Peripheral Identification 2 246 0xFEC WDTPeriphID3 RO 0x0000.0001 Watchdog Peripheral Identification 3 247 0xFF0 WDTPCellID0 RO 0x0000.000D Watchdog PrimeCell Identification 0 248 0xFF4 WDTPCellID1 RO 0x0000.00F0 Watchdog PrimeCell Identification 1 249 0xFF8 WDTPCellID2 RO 0x0000.0005 Watchdog PrimeCell Identification 2 250 0xFFC WDTPCellID3 RO 0x0000.00B1 Watchdog PrimeCell Identification 3 251 11.5 Description See page Type Register Descriptions The remainder of this section lists and describes the WDT registers, in numerical order by address offset. June 14, 2007 231 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 1: Watchdog Load (WDTLOAD), offset 0x000 This register is the 32-bit interval value used by the 32-bit counter. When this register is written, the value is immediately loaded and the counter restarts counting down from the new value. If the WDTLOAD register is loaded with 0x0000.0000, an interrupt is immediately generated. Watchdog Load (WDTLOAD) Base 0x4000.0000 Offset 0x000 Type R/W, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 15 14 13 12 11 10 9 8 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 23 22 21 20 19 18 17 16 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 WDTLoad Type Reset WDTLoad Type Reset Bit/Field Name Type 31:0 WDTLoad R/W Reset R/W 1 Description 0xFFFF.FFFF Watchdog Load Value 232 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: Watchdog Value (WDTVALUE), offset 0x004 This register contains the current count value of the timer. Watchdog Value (WDTVALUE) Base 0x4000.0000 Offset 0x004 Type RO, reset 0xFFFF.FFFF 31 30 29 28 27 26 25 24 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 15 14 13 12 11 10 9 8 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 23 22 21 20 19 18 17 16 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 7 6 5 4 3 2 1 0 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 RO 1 WDTValue Type Reset WDTValue Type Reset Bit/Field Name Type 31:0 WDTValue RO Reset RO 1 Description 0xFFFF.FFFF Watchdog Value Current value of the 32-bit down counter. June 14, 2007 233 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 3: Watchdog Control (WDTCTL), offset 0x008 This register is the watchdog control register. The watchdog timer can be configured to generate a reset signal (on second time-out) or an interrupt on time-out. When the watchdog interrupt has been enabled, all subsequent writes to the control register are ignored. The only mechanism that can re-enable writes is a hardware reset. Watchdog Control (WDTCTL) Base 0x4000.0000 Offset 0x008 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 1 0 RESEN INTEN R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 RESEN R/W 0 Watchdog Reset Enable 0: Disabled. 1: Enable the Watchdog module reset output. 0 INTEN R/W 0 Watchdog Interrupt Enable 0: Interrupt event disabled (once this bit is set, it can only be cleared by a hardware reset). 1: Interrupt event enabled. Once enabled, all writes are ignored. 234 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 4: Watchdog Interrupt Clear (WDTICR), offset 0x00C This register is the interrupt clear register. A write of any value to this register clears the Watchdog interrupt and reloads the 32-bit counter from the WDTLOAD register. Value for a read or reset is indeterminate. Watchdog Interrupt Clear (WDTICR) Base 0x4000.0000 Offset 0x00C Type WO, reset 31 30 29 28 27 26 25 24 WO - WO - WO - WO - WO - WO - WO - WO - 15 14 13 12 11 10 9 8 WO - WO - WO - WO - WO - WO - WO - WO - 23 22 21 20 19 18 17 16 WO - WO - WO - WO - WO - WO - WO - WO - 7 6 5 4 3 2 1 0 WO - WO - WO - WO - WO - WO - WO - WDTIntClr Type Reset WDTIntClr Type Reset Bit/Field Name Type Reset 31:0 WDTIntClr WO - WO - Description Watchdog Interrupt Clear June 14, 2007 235 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 5: Watchdog Raw Interrupt Status (WDTRIS), offset 0x010 This register is the raw interrupt status register. Watchdog interrupt events can be monitored via this register if the controller interrupt is masked. Watchdog Raw Interrupt Status (WDTRIS) Base 0x4000.0000 Offset 0x010 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 WDTRIS RO 0 Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 WDTRIS RO 0 Watchdog Raw Interrupt Status Gives the raw interrupt state (prior to masking) of WDTINTR. 236 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: Watchdog Masked Interrupt Status (WDTMIS), offset 0x014 This register is the masked interrupt status register. The value of this register is the logical AND of the raw interrupt bit and the Watchdog interrupt enable bit. Watchdog Masked Interrupt Status (WDTMIS) Base 0x4000.0000 Offset 0x014 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 WDTMIS RO 0 Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 WDTMIS RO 0 Watchdog Masked Interrupt Status Gives the masked interrupt state (after masking) of the WDTINTR interrupt. June 14, 2007 237 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 7: Watchdog Test (WDTTEST), offset 0x418 This register provides user-enabled stalling when the microcontroller asserts the CPU halt flag during debug. Watchdog Test (WDTTEST) Base 0x4000.0000 Offset 0x418 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 STALL R/W 0 reserved Bit/Field Name Type Reset Description 31:9 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 8 STALL R/W 0 Watchdog Stall Enable ® When set to 1, if the Stellaris microcontroller is stopped with a debugger, the watchdog timer stops counting. Once the microcontroller is restarted, the watchdog timer resumes counting. 7:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 238 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 8: Watchdog Lock (WDTLOCK), offset 0xC00 Writing 0x1ACCE551 to the WDTLOCK register enables write access to all other registers. Writing any other value to the WDTLOCK register re-enables the locked state for register writes to all the other registers. Reading the WDTLOCK register returns the lock status rather than the 32-bit value written. Therefore, when write accesses are disabled, reading the WDTLOCK register returns 0x0000.0001 (when locked; otherwise, the returned value is 0x0000.0000 (unlocked)). Watchdog Lock (WDTLOCK) Base 0x4000.0000 Offset 0xC00 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 WDTLock Type Reset WDTLock Type Reset Bit/Field Name Type Reset 31:0 WDTLock R/W 0x0000 R/W 0 Description Watchdog Lock A write of the value 0x1ACCE551 unlocks the watchdog registers for write access. A write of any other value reapplies the lock, preventing any register updates. A read of this register returns the following values: Locked: 0x0000.0001 Unlocked: 0x0000.0000 June 14, 2007 239 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 9: Watchdog Peripheral Identification 4 (WDTPeriphID4), offset 0xFD0 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog Peripheral Identification 4 (WDTPeriphID4) Base 0x4000.0000 Offset 0xFD0 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID4 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID4 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. WDT Peripheral ID Register[7:0] 240 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 10: Watchdog Peripheral Identification 5 (WDTPeriphID5), offset 0xFD4 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog Peripheral Identification 5 (WDTPeriphID5) Base 0x4000.0000 Offset 0xFD4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID5 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID5 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. WDT Peripheral ID Register[15:8] June 14, 2007 241 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 11: Watchdog Peripheral Identification 6 (WDTPeriphID6), offset 0xFD8 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog Peripheral Identification 6 (WDTPeriphID6) Base 0x4000.0000 Offset 0xFD8 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID6 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID6 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. WDT Peripheral ID Register[23:16] 242 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 12: Watchdog Peripheral Identification 7 (WDTPeriphID7), offset 0xFDC The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog Peripheral Identification 7 (WDTPeriphID7) Base 0x4000.0000 Offset 0xFDC Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID7 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID7 RO 0x00 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. WDT Peripheral ID Register[31:24] June 14, 2007 243 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 13: Watchdog Peripheral Identification 0 (WDTPeriphID0), offset 0xFE0 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog Peripheral Identification 0 (WDTPeriphID0) Base 0x4000.0000 Offset 0xFE0 Type RO, reset 0x0000.0005 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 1 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID0 RO 0x05 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Watchdog Peripheral ID Register[7:0] 244 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 14: Watchdog Peripheral Identification 1 (WDTPeriphID1), offset 0xFE4 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog Peripheral Identification 1 (WDTPeriphID1) Base 0x4000.0000 Offset 0xFE4 Type RO, reset 0x0000.0018 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 1 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID1 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID1 RO 0x18 RO 0 RO 0 RO 0 RO 0 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Watchdog Peripheral ID Register[15:8] June 14, 2007 245 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 15: Watchdog Peripheral Identification 2 (WDTPeriphID2), offset 0xFE8 The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog Peripheral Identification 2 (WDTPeriphID2) Base 0x4000.0000 Offset 0xFE8 Type RO, reset 0x0000.0018 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 1 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID2 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID2 RO 0x18 RO 0 RO 0 RO 0 RO 0 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Watchdog Peripheral ID Register[23:16] 246 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 16: Watchdog Peripheral Identification 3 (WDTPeriphID3), offset 0xFEC The WDTPeriphIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog Peripheral Identification 3 (WDTPeriphID3) Base 0x4000.0000 Offset 0xFEC Type RO, reset 0x0000.0001 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PID3 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID3 RO 0x01 RO 0 RO 0 RO 0 RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Watchdog Peripheral ID Register[31:24] June 14, 2007 247 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 17: Watchdog PrimeCell Identification 0 (WDTPCellID0), offset 0xFF0 The WDTPCellIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog PrimeCell Identification 0 (WDTPCellID0) Base 0x4000.0000 Offset 0xFF0 Type RO, reset 0x0000.000D 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 0 RO 1 reserved Type Reset reserved Type Reset CID0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID0 RO 0x0D Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Watchdog PrimeCell ID Register[7:0] 248 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 18: Watchdog PrimeCell Identification 1 (WDTPCellID1), offset 0xFF4 The WDTPCellIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog PrimeCell Identification 1 (WDTPCellID1) Base 0x4000.0000 Offset 0xFF4 Type RO, reset 0x0000.00F0 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 1 RO 1 RO 1 RO 1 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset CID1 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID1 RO 0xF0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Watchdog PrimeCell ID Register[15:8] June 14, 2007 249 Luminary Micro Confidential-Advance Product Information Watchdog Timer Register 19: Watchdog PrimeCell Identification 2 (WDTPCellID2), offset 0xFF8 The WDTPCellIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog PrimeCell Identification 2 (WDTPCellID2) Base 0x4000.0000 Offset 0xFF8 Type RO, reset 0x0000.0005 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 1 reserved Type Reset reserved Type Reset CID2 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID2 RO 0x05 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Watchdog PrimeCell ID Register[23:16] 250 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 20: Watchdog PrimeCell Identification 3 (WDTPCellID3 ), offset 0xFFC The WDTPCellIDn registers are hard-coded and the fields within the register determine the reset value. Watchdog PrimeCell Identification 3 (WDTPCellID3) Base 0x4000.0000 Offset 0xFFC Type RO, reset 0x0000.00B1 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 1 RO 0 RO 1 RO 1 RO 0 RO 0 RO 0 RO 1 reserved Type Reset reserved Type Reset CID3 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID3 RO 0xB1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Watchdog PrimeCell ID Register[31:24] June 14, 2007 251 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) 12 Analog-to-Digital Converter (ADC) ADC An analog-to-digital converter (ADC) is a peripheral that converts a continuous analog voltage to a discrete digital number. ® The Stellaris ADC module features 10-bit conversion resolution and supports eight input channels, plus an internal temperature sensor. The ADC module contains a programmable sequencer which allows for the sampling of multiple analog input sources without controller intervention. Each sample sequence provides flexible programming with fully configurable input source, trigger events, interrupt generation, and sequence priority. ® The Stellaris ADC provides the following features: ■ Eight analog input channels ■ Single-ended and differential-input configurations ■ Internal temperature sensor ■ Sample rate of one million samples/second ■ Four programmable sample conversion sequences from one to eight entries long, with corresponding conversion result FIFOs ■ Flexible trigger control – Controller (software) – Timers – Analog Comparators – GPIO ■ Hardware averaging of up to 64 samples for improved accuracy 252 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 12.1 Block Diagram Figure 12-1. ADC Module Block Diagram Trigger Events Comparator GPIO (PB4) Timer PWM Analog Inputs SS3 Comparator GPIO (PB4) Timer PWM SS2 Control/Status Sample Sequencer 0 ADCACTSS ADCSSMUX0 ADCOSTAT ADCSSCTL0 ADCUSTAT ADCSSFSTAT0 ADCSSPRI Sample Sequencer 1 ADCSSMUX1 Comparator GPIO (PB4) Timer PWM ADCSSCTL1 SS1 ADCSSFSTAT1 Hardware Averager ADCSAC Sample Sequencer 2 Comparator GPIO (PB4) Timer PWM SS0 ADCSSMUX2 ADCSSCTL2 ADCSSFSTAT2 ADCEMUX ADCPSSI SS0 Interrupt SS1 Interrupt SS2 Interrupt SS3 Interrupt 12.2 Analog-to-Digital Converter FIFO Block ADCSSFIFO0 ADCSSFIFO1 Interrupt Control Sample Sequencer 3 ADCIM ADCSSMUX3 ADCRIS ADCSSCTL3 ADCISC ADCSSFSTAT3 ADCSSFIFO2 ADCSSFIFO3 Functional Description ® The Stellaris ADC collects sample data by using a programmable sequence-based approach instead of the traditional single or double-sampling approach found on many ADC modules. Each sample sequence is a fully programmed series of consecutive (back-to-back) samples, allowing the ADC to collect data from multiple input sources without having to be re-configured or serviced by the controller. The programming of each sample in the sample sequence includes parameters such as the input source and mode (differential versus single-ended input), interrupt generation on sample completion, and the indicator for the last sample in the sequence. 12.2.1 Sample Sequencers The sampling control and data capture is handled by the Sample Sequencers. All of the sequencers are identical in implementation except for the number of samples that can be captured and the depth of the FIFO. Table 12-1 on page 253 shows the maximum number of samples that each Sequencer can capture and its corresponding FIFO depth. In this implementation, each FIFO entry is a 32-bit word, with the lower 10 bits containing the conversion result. Table 12-1. Samples and FIFO Depth of Sequencers Sequencer Number of Samples Depth of FIFO SS3 1 1 SS2 4 4 SS1 4 4 SS0 8 8 June 14, 2007 253 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) For a given sample sequence, each sample is defined by two 4-bit nibbles in the ADC Sample Sequence Input Multiplexer Select (ADCSSMUXn) and ADC Sample Sequence Control (ADCSSCTLn) registers, where "n" corresponds to the sequence number. The ADCSSMUXn nibbles select the input pin, while the ADCSSCTLn nibbles contain the sample control bits corresponding to parameters such as temperature sensor selection, interrupt enable, end of sequence, and differential input mode. Sample Sequencers are enabled by setting the respective ASENn bit in the ADC Active Sample Sequencer (ADCACTSS) register, but can be configured before being enabled. When configuring a sample sequence, multiple uses of the same input pin within the same sequence is allowed. In the ADCSSCTLn register, the Interrupt Enable (IE) bits can be set for any combination of samples, allowing interrupts to be generated after every sample in the sequence if necessary. Also, the END bit can be set at any point within a sample sequence. For example, if Sequencer 0 is used, the END bit can be set in the nibble associated with the fifth sample, allowing Sequencer 0 to complete execution of the sample sequence after the fifth sample. After a sample sequence completes execution, the result data can be retrieved from the ADC Sample Sequence Result FIFO (ADCSSFIFOn) registers. The FIFOs are simple circular buffers that read a single address to "pop" result data. For software debug purposes, the positions of the FIFO head and tail pointers are visible in the ADC Sample Sequence FIFO Status (ADCSSFSTATn) registers along with FULL and EMPTY status flags. Overflow and underflow conditions are monitored using the ADCOSTAT and ADCUSTAT registers. 12.2.2 Module Control Outside of the Sample Sequencers, the remainder of the control logic is responsible for tasks such as interrupt generation, sequence prioritization, and trigger configuration. Most of the ADC control logic runs at the ADC clock rate of 14-18 MHz. The internal ADC divider is configured automatically by hardware when the system XTAL is selected. The automatic clock ® divider configuration targets 16.667 MHz operation for all Stellaris devices. 12.2.2.1 Interrupts The Sample Sequencers dictate the events that cause interrupts, but they don't have control over whether the interrupt is actually sent to the interrupt controller. The ADC module's interrupt signal is controlled by the state of the MASK bits in the ADC Interrupt Mask (ADCIM) register. Interrupt status can be viewed at two locations: the ADC Raw Interrupt Status (ADCRIS) register, which shows the raw status of a Sample Sequencer's interrupt signal, and the ADC Interrupt Status and Clear (ADCISC) register, which shows the logical AND of the ADCRIS register’s INR bit and the ADCIM register’s MASK bits. Interrupts are cleared by writing a 1 to the corresponding IN bit in ADCISC. 12.2.2.2 Prioritization When sampling events (triggers) happen concurrently, they are prioritized for processing by the values in the ADC Sample Sequencer Priority (ADCSSPRI) register. Valid priority values are in the range of 0-3, with 0 being the highest priority and 3 being the lowest. Multiple active Sample Sequencer units with the same priority do not provide consistent results, so software must ensure that all active Sample Sequencer units have a unique priority value. 12.2.2.3 Sampling Events Sample triggering for each Sample Sequencer is defined in the ADC Event Multiplexer Select ® (ADCEMUX) register. The external peripheral triggering sources vary by Stellaris family member, 254 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller but all devices share the "Controller" and "Always" triggers. Software can initiate sampling by setting the CH bits in the ADC Processor Sample Sequence Initiate (ADCPSSI) register. When using the "Always" trigger, care must be taken. If a sequence's priority is too high, it is possible to starve other lower priority sequences. 12.2.3 Hardware Sample Averaging Circuit Higher precision results can be generated using the hardware averaging circuit, however, the improved results are at the cost of throughput. Up to 64 samples can be accumulated and averaged to form a single data entry in the sequencer FIFO. Throughput is decreased proportionally to the number of samples in the averaging calculation. For example, if the averaging circuit is configured to average 16 samples, the throughput is decreased by a factor of 16. By default the averaging circuit is off and all data from the converter passes through to the sequencer FIFO. The averaging hardware is controlled by the ADC Sample Averaging Control (ADCSAC) register (see page 268). There is a single averaging circuit and all input channels receive the same amount of averaging whether they are single-ended or differential. 12.2.4 Analog-to-Digital Converter The converter itself generates a 10-bit output value for selected analog input. Special analog pads are used to minimize the distortion on the input. 12.2.5 Test Modes There is a user-available test mode that allows for loopback operation within the digital portion of the ADC module. This can be useful for debugging software without having to provide actual analog stimulus. This mode is available through the ADC Test Mode Loopback (ADCTMLB) register (see page 283). 12.2.6 Internal Temperature Sensor The internal temperature sensor provides an analog temperature reading as well as a reference voltage. The voltage at the output terminal SENSO is given by the following equation: SENSO = 2.7 - ((T + 55) / 75) This relation is shown in Figure 12-2 on page 256. June 14, 2007 255 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Figure 12-2. Internal Temperature Sensor Characteristic 12.3 Initialization and Configuration In order for the ADC module to be used, the PLL must be enabled and using a supported crystal frequency (see the RCC register). Using unsupported frequencies can cause faulty operation in the ADC module. 12.3.1 Module Initialization Initialization of the ADC module is a simple process with very few steps. The main steps include enabling the clock to the ADC and reconfiguring the Sample Sequencer priorities (if needed). The initialization sequence for the ADC is as follows: 1. Enable the ADC clock by writing a value of 0x0001.0000 to the RCGC1 register (see page 97). 2. If required by the application, reconfigure the Sample Sequencer priorities in the ADCSSPRI register. The default configuration has Sample Sequencer 0 with the highest priority, and Sample Sequencer 3 as the lowest priority. 12.3.2 Sample Sequencer Configuration Configuration of the Sample Sequencers is slightly more complex than the module initialization since each sample sequence is completely programmable. The configuration for each Sample Sequencer should be as follows: 1. Ensure that the Sample Sequencer is disabled by writing a 0 to the corresponding ASEN bit in the ADCACTSS register. Programming of the Sample Sequencers is allowed without having them enabled. Disabling the Sequencer during programming prevents erroneous execution if a trigger event were to occur during the configuration process. 2. Configure the trigger event for the Sample Sequencer in the ADCEMUX register. 3. For each sample in the sample sequence, configure the corresponding input source in the ADCSSMUXn register. 256 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 4. For each sample in the sample sequence, configure the sample control bits in the corresponding nibble in the ADCSSCTLn register. When programming the last nibble, ensure that the END bit is set. Failure to set the END bit causes unpredictable behavior. 5. If interrupts are to be used, write a 1 to the corresponding MASK bit in the ADCIM register. 6. Enable the Sample Sequencer logic by writing a 1 to the corresponding ASEN bit in the ADCACTSS register. 12.4 Register Map Table 12-2 on page 257 lists the ADC registers. The offset listed is a hexadecimal increment to the register’s address, relative to the ADC base address of 0x4003.8000. Table 12-2. ADC Register Map Description See page Offset Name Type Reset 0x000 ADCACTSS R/W 0x0000.0000 ADC Active Sample Sequencer 259 0x004 ADCRIS RO 0x0000.0000 ADC Raw Interrupt Status 260 0x008 ADCIM R/W 0x0000.0000 ADC Interrupt Mask 261 0x00C ADCISC R/W1C 0x0000.0000 ADC Interrupt Status and Clear 262 0x010 ADCOSTAT R/W1C 0x0000.0000 ADC Overflow Status 263 0x014 ADCEMUX R/W 0x0000.0000 ADC Event Multiplexer Select 264 0x018 ADCUSTAT R/W1C 0x0000.0000 ADC Underflow Status 265 0x020 ADCSSPRI R/W 0x0000.3210 ADC Sample Sequencer Priority 266 0x028 ADCPSSI WO - ADC Processor Sample Sequence Initiate 267 0x030 ADCSAC R/W 0x0000.0000 ADC Sample Averaging Control 268 0x040 ADCSSMUX0 R/W 0x0000.0000 ADC Sample Sequence Input Multiplexer Select 0 269 0x044 ADCSSCTL0 R/W 0x0000.0000 ADC Sample Sequence Control 0 271 0x048 ADCSSFIFO0 RO 0x0000.0000 ADC Sample Sequence Result FIFO 0 273 0x04C ADCSSFSTAT0 RO 0x0000.0100 ADC Sample Sequence FIFO 0 Status 274 0x060 ADCSSMUX1 R/W 0x0000.0000 ADC Sample Sequence Input Multiplexer Select 1 275 0x064 ADCSSCTL1 R/W 0x0000.0000 ADC Sample Sequence Control 1 276 0x068 ADCSSFIFO1 RO 0x0000.0000 ADC Sample Sequence Result FIFO 1 273 0x06C ADCSSFSTAT1 RO 0x0000.0100 ADC Sample Sequence FIFO 1 Status 274 0x080 ADCSSMUX2 R/W 0x0000.0000 ADC Sample Sequence Input Multiplexer Select 2 277 0x084 ADCSSCTL2 R/W 0x0000.0000 ADC Sample Sequence Control 2 278 0x088 ADCSSFIFO2 RO 0x0000.0000 ADC Sample Sequence Result FIFO 2 273 0x08C ADCSSFSTAT2 RO 0x0000.0100 ADC Sample Sequence FIFO 2 Status 274 0x0A0 ADCSSMUX3 R/W 0x0000.0000 ADC Sample Sequence Input Multiplexer Select 3 279 June 14, 2007 257 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Name Type Reset 0x0A4 ADCSSCTL3 R/W 0x0000.0002 ADC Sample Sequence Control 3 280 0x0A8 ADCSSFIFO3 RO 0x0000.0000 ADC Sample Sequence Result FIFO 3 281 0x0AC ADCSSFSTAT3 RO 0x0000.0100 ADC Sample Sequence FIFO 3 Status 282 0x100 ADCTMLB R/W 0x0000.0000 ADC Test Mode Loopback 283 12.5 Description See page Offset Register Descriptions The remainder of this section lists and describes the ADC registers, in numerical order by address offset. 258 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 1: ADC Active Sample Sequencer (ADCACTSS), offset 0x000 This register controls the activation of the Sample Sequencers. Each Sample Sequencer can be enabled/disabled independently. ADC Active Sample Sequencer (ADCACTSS) Base 0x4003.8000 Offset 0x000 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 ASEN3 ASEN2 ASEN1 ASEN0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 ASEN3 R/W 0 Specifies whether Sample Sequencer 3 is enabled. If set, the sample sequence logic for Sequencer 3 is active. Otherwise, the Sequencer is inactive. 2 ASEN2 R/W 0 Specifies whether Sample Sequencer 2 is enabled. If set, the sample sequence logic for Sequencer 2 is active. Otherwise, the Sequencer is inactive. 1 ASEN1 R/W 0 Specifies whether Sample Sequencer 1 is enabled. If set, the sample sequence logic for Sequencer 1 is active. Otherwise, the Sequencer is inactive. 0 ASEN0 R/W 0 Specifies whether Sample Sequencer 0 is enabled. If set, the sample sequence logic for Sequencer 0 is active. Otherwise, the Sequencer is inactive. June 14, 2007 259 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 2: ADC Raw Interrupt Status (ADCRIS), offset 0x004 This register shows the status of the raw interrupt signal of each Sample Sequencer. These bits may be polled by software to look for interrupt conditions without having to generate controller interrupts. ADC Raw Interrupt Status (ADCRIS) Base 0x4003.8000 Offset 0x004 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 INR3 INR2 INR1 INR0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 INR3 RO 0 Set by hardware when a sample with its respective ADCSSCTL3 IE bit has completed conversion. This bit is cleared by writing a 1 to the ADCISC IN3 bit. 2 INR2 RO 0 Set by hardware when a sample with its respective ADCSSCTL2 IE bit has completed conversion. This bit is cleared by writing a 1 to the ADCISC IN2 bit. 1 INR1 RO 0 Set by hardware when a sample with its respective ADCSSCTL1 IE bit has completed conversion. This bit is cleared by writing a 1 to the ADCISC IN1 bit. 0 INR0 RO 0 Set by hardware when a sample with its respective ADCSSCTL0 IE bit has completed conversion. This bit is cleared by writing a 1 to the ADCISC IN0 bit. 260 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 3: ADC Interrupt Mask (ADCIM), offset 0x008 This register controls whether the Sample Sequencer raw interrupt signals are promoted to controller interrupts. The raw interrupt signal for each Sample Sequencer can be masked independently. ADC Interrupt Mask (ADCIM) Base 0x4003.8000 Offset 0x008 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 MASK3 MASK2 MASK1 MASK0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 MASK3 R/W 0 Specifies whether the raw interrupt signal from Sample Sequencer 3 (ADCRIS register INR3 bit) is promoted to a controller interrupt. If set, the raw interrupt signal is promoted to a controller interrupt. Otherwise, it is not. 2 MASK2 R/W 0 Specifies whether the raw interrupt signal from Sample Sequencer 2 (ADCRIS register INR2 bit) is promoted to a controller interrupt. If set, the raw interrupt signal is promoted to a controller interrupt. Otherwise, it is not. 1 MASK1 R/W 0 Specifies whether the raw interrupt signal from Sample Sequencer 1 (ADCRIS register INR1 bit) is promoted to a controller interrupt. If set, the raw interrupt signal is promoted to a controller interrupt. Otherwise, it is not. 0 MASK0 R/W 0 Specifies whether the raw interrupt signal from Sample Sequencer 0 (ADCRIS register INR0 bit) is promoted to a controller interrupt. If set, the raw interrupt signal is promoted to a controller interrupt. Otherwise, it is not. June 14, 2007 261 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 4: ADC Interrupt Status and Clear (ADCISC), offset 0x00C This register provides the mechanism for clearing interrupt conditions, and shows the status of controller interrupts generated by the Sample Sequencers. When read, each bit field is the logical AND of the respective INR and MASK bits. Interrupts are cleared by writing a 1 to the corresponding bit position. If software is polling the ADCRIS instead of generating interrupts, the INR bits are still cleared via the ADCISC register, even if the IN bit is not set. ADC Interrupt Status and Clear (ADCISC) Base 0x4003.8000 Offset 0x00C Type R/W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 IN3 IN2 IN1 IN0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 IN3 R/W1C 0 This bit is set by hardware when the MASK3 and INR3 bits are both 1, providing a level-based interrupt to the controller. It is cleared by writing a 1, and also clears the INR3 bit. 2 IN2 R/W1C 0 This bit is set by hardware when the MASK2 and INR2 bits are both 1, providing a level based interrupt to the controller. It is cleared by writing a 1, and also clears the INR2 bit. 1 IN1 R/W1C 0 This bit is set by hardware when the MASK1 and INR1 bits are both 1, providing a level based interrupt to the controller. It is cleared by writing a 1, and also clears the INR1 bit. 0 IN0 R/W1C 0 This bit is set by hardware when the MASK0 and INR0 bits are both 1, providing a level based interrupt to the controller. It is cleared by writing a 1, and also clears the INR0 bit. 262 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 5: ADC Overflow Status (ADCOSTAT), offset 0x010 This register indicates overflow conditions in the Sample Sequencer FIFOs. Once the overflow condition has been handled by software, the condition can be cleared by writing a 1 to the corresponding bit position. ADC Overflow Status (ADCOSTAT) Base 0x4003.8000 Offset 0x010 Type R/W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 OV3 OV2 OV1 OV0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 OV3 R/W1C 0 This bit specifies that the FIFO for Sample Sequencer 3 has hit an overflow condition where the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped and this bit is set by hardware to indicate the occurrence of dropped data. This bit is cleared by writing a 1. 2 OV2 R/W1C 0 This bit specifies that the FIFO for Sample Sequencer 2 has hit an overflow condition where the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped and this bit is set by hardware to indicate the occurrence of dropped data. This bit is cleared by writing a 1. 1 OV1 R/W1C 0 This bit specifies that the FIFO for Sample Sequencer 1 has hit an overflow condition where the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped and this bit is set by hardware to indicate the occurrence of dropped data. This bit is cleared by writing a 1. 0 OV0 R/W1C 0 This bit specifies that the FIFO for Sample Sequencer 0 has hit an overflow condition where the FIFO is full and a write was requested. When an overflow is detected, the most recent write is dropped and this bit is set by hardware to indicate the occurrence of dropped data. This bit is cleared by writing a 1. June 14, 2007 263 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 6: ADC Event Multiplexer Select (ADCEMUX), offset 0x014 The ADCEMUX selects the event (trigger) that initiates sampling for each Sample Sequencer. Each Sample Sequencer can be configured with a unique trigger source. ADC Event Multiplexer Select (ADCEMUX) Base 0x4003.8000 Offset 0x014 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset EM3 Type Reset EM2 EM1 EM0 Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:12 EM3 R/W 0 This field selects the trigger source for Sample Sequencer 3. The valid configurations for this field are: EM Binary Value Event 0000 Controller (default) 0001 Analog Comparator 0 0010 Analog Comparator 1 0011 Analog Comparator 2 0100 External (GPIO PB4) 0101 Timer 0110 Reserved 0111 Reserved 1000 Reserved 1001-1110 reserved 1111 Always (continuously sample) 11:8 EM2 R/W 0 This field selects the trigger source for Sample Sequencer 2. The encodings are the same as those for EM3. 7:4 EM1 R/W 0 This field selects the trigger source for Sample Sequencer 1. The encodings are the same as those for EM3. 3:0 EM0 R/W 0 This field selects the trigger source for Sample Sequencer 0. The encodings are the same as those for EM3. 264 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 7: ADC Underflow Status (ADCUSTAT), offset 0x018 This register indicates underflow conditions in the Sample Sequencer FIFOs. The corresponding underflow condition can be cleared by writing a 1 to the relevant bit position. ADC Underflow Status (ADCUSTAT) Base 0x4003.8000 Offset 0x018 Type R/W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 UV3 UV2 UV1 UV0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W1C 0 R/W1C 0 R/W1C 0 R/W1C 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 UV3 R/W1C 0 This bit specifies that the FIFO for Sample Sequencer 3 has hit an underflow condition where the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. This bit is cleared by writing a 1. 2 UV2 R/W1C 0 This bit specifies that the FIFO for Sample Sequencer 2 has hit an underflow condition where the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. This bit is cleared by writing a 1. 1 UV1 R/W1C 0 This bit specifies that the FIFO for Sample Sequencer 1 has hit an underflow condition where the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. This bit is cleared by writing a 1. 0 UV0 R/W1C 0 This bit specifies that the FIFO for Sample Sequencer 0 has hit an underflow condition where the FIFO is empty and a read was requested. The problematic read does not move the FIFO pointers, and 0s are returned. This bit is cleared by writing a 1. June 14, 2007 265 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 8: ADC Sample Sequencer Priority (ADCSSPRI), offset 0x020 This register sets the priority for each of the Sample Sequencers. Out of reset, Sequencer 0 has the highest priority, and sample sequence 3 has the lowest priority. When reconfiguring sequence priorities, each sequence must have a unique priority or the ADC behavior is inconsistent. ADC Sample Sequencer Priority (ADCSSPRI) Base 0x4003.8000 Offset 0x020 Type R/W, reset 0x0000.3210 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 R/W 1 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 R/W 0 RO 0 RO 0 R/W 0 R/W 1 RO 0 RO 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 RO 0 SS3 R/W 1 reserved RO 0 SS2 R/W 1 reserved SS1 reserved SS0 R/W 0 Bit/Field Name Type Reset Description 31:14 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 13:12 SS3 R/W 0x3 The SS3 field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 3. A priority encoding of 0 is highest and 3 is lowest. The priorities assigned to the Sequencers must be uniquely mapped. ADC behavior is not consistent if two or more fields are equal. 11:10 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9:8 SS2 R/W 0x2 The SS2 field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 2. 7:6 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5:4 SS1 R/W 0x1 The SS1 field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 1. 3:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1:0 SS0 R/W 0x0 The SS0 field contains a binary-encoded value that specifies the priority encoding of Sample Sequencer 0. 266 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 9: ADC Processor Sample Sequence Initiate (ADCPSSI), offset 0x028 This register provides a mechanism for application software to initiate sampling in the Sample Sequencers. Sample sequences can be initiated individually or in any combination. When multiple sequences are triggered simultaneously, the priority encodings in ADCSSPRI dictate execution order. ADC Processor Sample Sequence Initiate (ADCPSSI) Base 0x4003.8000 Offset 0x028 Type WO, reset 31 30 29 28 27 26 25 24 WO - WO - WO - WO - WO - WO - WO - WO - 15 14 13 12 11 10 9 WO - WO - WO - WO - WO - WO - WO - 23 22 21 20 19 18 17 16 WO - WO - WO - WO - WO - WO - WO - WO - 8 7 6 5 4 3 2 1 0 SS3 SS2 SS1 SS0 WO - WO - WO - WO - WO - WO - WO - WO - WO - reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved WO - Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 SS3 WO - Only a write by software is valid; a read of the register returns no meaningful data. When set by software, sampling is triggered on Sample Sequencer 3, assuming the Sequencer is enabled in the ADCACTSS register. 2 SS2 WO - Only a write by software is valid; a read of the register returns no meaningful data. When set by software, sampling is triggered on Sample Sequencer 2, assuming the Sequencer is enabled in the ADCACTSS register. 1 SS1 WO - Only a write by software is valid; a read of the register returns no meaningful data. When set by software, sampling is triggered on Sample Sequencer 1, assuming the Sequencer is enabled in the ADCACTSS register. 0 SS0 WO - Only a write by software is valid; a read of the register returns no meaningful data. When set by software, sampling is triggered on Sample Sequencer 0, assuming the Sequencer is enabled in the ADCACTSS register. June 14, 2007 267 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 10: ADC Sample Averaging Control (ADCSAC), offset 0x030 This register controls the amount of hardware averaging applied to conversion results. The final AVG conversion result stored in the FIFO is averaged from 2 consecutive ADC samples at the specified ADC speed. If AVG is 0, the sample is passed directly through without any averaging. If AVG=6, then 64 consecutive ADC samples are averaged to generate one result in the sequencer FIFO. An AVG = 7 provides unpredictable results. ADC Sample Averaging Control (ADCSAC) Base 0x4003.8000 Offset 0x030 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 AVG R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2:0 AVG R/W 0 Specifies the amount of hardware averaging that will be applied to ADC samples. The AVG field can be any value between 0 and 6. Entering a value of 7 creates unpredictable results. 268 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 11: ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0), offset 0x040 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 0. This register is 32-bits wide and contains information for eight possible samples. ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0) Base 0x4003.8000 Offset 0x040 Type R/W, reset 0x0000.0000 31 30 reserved Type Reset 28 MUX7 27 26 reserved 25 24 MUX6 23 22 reserved 21 20 MUX5 19 18 reserved 17 16 MUX4 RO 0 R/W 0 R/W 0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 reserved Type Reset 29 RO 0 MUX3 R/W 0 R/W 0 reserved R/W 0 RO 0 MUX2 R/W 0 R/W 0 reserved R/W 0 RO 0 MUX1 R/W 0 R/W 0 reserved R/W 0 RO 0 MUX0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 30:28 MUX7 R/W 0 The MUX7 field is used during the eighth sample of a sequence executed with the Sample Sequencer. It specifies which of the analog inputs is sampled for the analog-to-digital conversion. The value set here indicates the corresponding pin, for example, a value of 1 indicates the input is ADC1. 27 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 26:24 MUX6 R/W 0 The MUX6 field is used during the seventh sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 23 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 22:20 MUX5 R/W 0 The MUX5 field is used during the sixth sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 19 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 18:16 MUX4 R/W 0 The MUX4 field is used during the fifth sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. June 14, 2007 269 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset Description 15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14:12 MUX3 R/W 0 The MUX3 field is used during the fourth sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10:8 MUX2 R/W 0 The MUX2 field is used during the third sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6:4 MUX1 R/W 0 The MUX1 field is used during the second sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2:0 MUX0 R/W 0 The MUX0 field is used during the first sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 270 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 12: ADC Sample Sequence Control 0 (ADCSSCTL0), offset 0x044 This register contains the configuration information for each sample for a sequence executed with Sample Sequencer 0. When configuring a sample sequence, the END bit must be set at some point, whether it be after the first sample, last sample, or any sample in between. This register is 32-bits wide and contains information for eight possible samples. ADC Sample Sequence Control 0 (ADCSSCTL0) Base 0x4003.8000 Offset 0x044 Type R/W, reset 0x0000.0000 Type Reset Type Reset 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 TS7 IE7 END7 D7 TS6 IE6 END6 D6 TS5 IE5 END5 D5 TS4 IE4 END4 D4 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 TS3 IE3 END3 D3 TS2 IE2 END2 D2 TS1 IE1 END1 D1 TS0 IE0 END0 D0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31 TS7 R/W 0 The TS7 bit is used during the eighth sample of the sample sequence and specifies the input source of the sample. If set, the temperature sensor is read. Otherwise, the input pin specified by the ADCSSMUX register is read. 30 IE7 R/W 0 The IE7 bit is used during the eighth sample of the sample sequence and specifies whether the raw interrupt signal (INR0 bit) is asserted at the end of the sample's conversion. If the MASK0 bit in the ADCIM register is set, the interrupt is promoted to a controller-level interrupt. When this bit is set, the raw interrupt is asserted, otherwise it is not. It is legal to have multiple samples within a sequence generate interrupts. 29 END7 R/W 0 The END7 bit indicates that this is the last sample of the sequence. It is possible to end the sequence on any sample position. Samples defined after the sample containing a set END are not requested for conversion even though the fields may be non-zero. It is required that software write the END bit somewhere within the sequence. (Sample Sequencer 3, which only has a single sample in the sequence, is hardwired to have the END0 bit set.) Setting this bit indicates that this sample is the last in the sequence. 28 D7 R/W 0 The D7 bit indicates that the analog input is to be differentially sampled. The corresponding ADCSSMUXx nibble must be set to the pair number "i", where the paired inputs are "2i and 2i+1". The temperature sensor does not have a differential option. When set, the analog inputs are differentially sampled. 27 TS6 R/W 0 Same definition as TS7 but used during the seventh sample. 26 IE6 R/W 0 Same definition as IE7 but used during the seventh sample. 25 END6 R/W 0 Same definition as END7 but used during the seventh sample. 24 D6 R/W 0 Same definition as D7 but used during the seventh sample. 23 TS5 R/W 0 Same definition as TS7 but used during the sixth sample. June 14, 2007 271 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset Description 22 IE5 R/W 0 Same definition as IE7 but used during the sixth sample. 21 END5 R/W 0 Same definition as END7 but used during the sixth sample. 20 D5 R/W 0 Same definition as D7 but used during the sixth sample. 19 TS4 R/W 0 Same definition as TS7 but used during the fifth sample. 18 IE4 R/W 0 Same definition as IE7 but used during the fifth sample. 17 END4 R/W 0 Same definition as END7 but used during the fifth sample. 16 D4 R/W 0 Same definition as D7 but used during the fifth sample. 15 TS3 R/W 0 Same definition as TS7 but used during the fourth sample. 14 IE3 R/W 0 Same definition as IE7 but used during the fourth sample. 13 END3 R/W 0 Same definition as END7 but used during the fourth sample. 12 D3 R/W 0 Same definition as D7 but used during the fourth sample. 11 TS2 R/W 0 Same definition as TS7 but used during the third sample. 10 IE2 R/W 0 Same definition as IE7 but used during the third sample. 9 END2 R/W 0 Same definition as END7 but used during the third sample. 8 D2 R/W 0 Same definition as D7 but used during the third sample. 7 TS1 R/W 0 Same definition as TS7 but used during the second sample. 6 IE1 R/W 0 Same definition as IE7 but used during the second sample. 5 END1 R/W 0 Same definition as END7 but used during the second sample. 4 D1 R/W 0 Same definition as D7 but used during the second sample. 3 TS0 R/W 0 Same definition as TS7 but used during the first sample. 2 IE0 R/W 0 Same definition as IE7 but used during the first sample. 1 END0 R/W 0 Same definition as END7 but used during the first sample. Since this sequencer has only one entry, this bit must be set. 0 D0 R/W 0 Same definition as D7 but used during the first sample. 272 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 13: ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0), offset 0x048 Register 14: ADC Sample Sequence Result FIFO 1 (ADCSSFIFO1), offset 0x068 Register 15: ADC Sample Sequence Result FIFO 2 (ADCSSFIFO2), offset 0x088 This register contains the conversion results for samples collected with the Sample Sequencer (the ADCSSFIF0 register is used for Sample Sequencer 0, ADCSSFIFO1 for Sequencer 1, and ADCSSFIFO2 for Sequencer 2). Reads of this register return conversion result data in the order sample 0, sample 1, and so on, until the FIFO is empty. If the FIFO is not properly handled by software, overflow and underflow conditions are registered in the ADCOSTAT and ADCUSTAT registers. ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0) Base 0x4003.8000 Offset 0x048 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 DATA Bit/Field Name Type Reset Description 31:10 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9:0 DATA RO 0 Conversion result data. June 14, 2007 273 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 16: ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0), offset 0x04C Register 17: ADC Sample Sequence FIFO 1 Status (ADCSSFSTAT1), offset 0x06C Register 18: ADC Sample Sequence FIFO 2 Status (ADCSSFSTAT2), offset 0x08C This register provides a window into the Sample Sequencer, providing full/empty status information as well as the positions of the head and tail pointers. The reset value of 0x100 indicates an empty FIFO. The ADCSSFSTAT0 register provides status on FIF0, ADCSSFSTAT1 on FIFO1, and ADCSSFSTAT2 on FIFO2. ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0) Base 0x4003.8000 Offset 0x04C Type RO, reset 0x0000.0100 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 5 4 3 2 1 0 RO 0 RO 0 reserved Type Reset RO 0 15 RO 0 RO 0 14 13 reserved Type Reset RO 0 RO 0 RO 0 RO 0 12 11 FULL RO 0 RO 0 RO 0 RO 0 10 9 reserved RO 0 RO 0 RO 0 RO 0 8 7 6 EMPTY RO 0 RO 0 RO 1 HPTR RO 0 RO 0 TPTR RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 FULL RO 0 When set, indicates that the FIFO is currently full. 11:9 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 8 EMPTY RO 1 When set, indicates that the FIFO is currently empty. 7:4 HPTR RO 0 This field contains the current "head" pointer index for the FIFO, that is, the next entry to be written. 3:0 TPTR RO 0 This field contains the current "tail" pointer index for the FIFO, that is, the next entry to be read. 274 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 19: ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1), offset 0x060 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 1. This register is 16-bits wide and contains information for four possible samples. ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1) Base 0x4003.8000 Offset 0x060 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 reserved Type Reset RO 0 RO 0 15 14 reserved Type Reset RO 0 RO 0 RO 0 13 12 MUX3 R/W 0 R/W 0 RO 0 RO 0 11 10 reserved R/W 0 RO 0 RO 0 RO 0 9 8 MUX2 R/W 0 R/W 0 reserved R/W 0 RO 0 MUX1 R/W 0 R/W 0 reserved R/W 0 RO 0 MUX0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14:12 MUX3 R/W 0 The MUX3 field is used during the fourth sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10:8 MUX2 R/W 0 The MUX2 field is used during the third sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6:4 MUX1 R/W 0 The MUX1 field is used during the second sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2:0 MUX0 R/W 0 The MUX0 field is used during the first sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. June 14, 2007 275 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 20: ADC Sample Sequence Control 1 (ADCSSCTL1), offset 0x064 This register contains the configuration information for each sample for a sequence executed with Sample Sequencer 1. When configuring a sample sequence, the END bit must be set at some point, whether it be after the first sample, last sample, or any sample in between. This register is 16-bits wide and contains information for four possible samples. ADC Sample Sequence Control 1 (ADCSSCTL1) Base 0x4003.8000 Offset 0x064 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 TS3 IE3 END3 D3 TS2 IE2 END2 D2 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 TS1 IE1 END1 D1 TS0 IE0 END0 D0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset Type Reset Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15 TS3 R/W 0 Same definition as TS7 but used during the fourth sample. 14 IE3 R/W 0 Same definition as IE7 but used during the fourth sample. 13 END3 R/W 0 Same definition as END7 but used during the fourth sample. 12 D3 R/W 0 Same definition as D7 but used during the fourth sample. 11 TS2 R/W 0 Same definition as TS7 but used during the third sample. 10 IE2 R/W 0 Same definition as IE7 but used during the third sample. 9 END2 R/W 0 Same definition as END7 but used during the third sample. 8 D2 R/W 0 Same definition as D7 but used during the third sample. 7 TS1 R/W 0 Same definition as TS7 but used during the second sample. 6 IE1 R/W 0 Same definition as IE7 but used during the second sample. 5 END1 R/W 0 Same definition as END7 but used during the second sample. 4 D1 R/W 0 Same definition as D7 but used during the second sample. 3 TS0 R/W 0 Same definition as TS7 but used during the first sample. 2 IE0 R/W 0 Same definition as IE7 but used during the first sample. 1 END0 R/W 0 Same definition as END7 but used during the first sample. Since this sequencer has only one entry, this bit must be set. 0 D0 R/W 0 Same definition as D7 but used during the first sample. 276 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 21: ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2), offset 0x080 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 2. This register is 16-bits wide and contains information for four possible samples. ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2) Base 0x4003.8000 Offset 0x080 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 reserved Type Reset RO 0 RO 0 15 14 reserved Type Reset RO 0 RO 0 RO 0 13 12 MUX3 R/W 0 R/W 0 RO 0 RO 0 11 10 reserved R/W 0 RO 0 RO 0 RO 0 9 8 MUX2 R/W 0 R/W 0 reserved R/W 0 RO 0 MUX1 R/W 0 R/W 0 reserved R/W 0 RO 0 MUX0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14:12 MUX3 R/W 0 The MUX3 field is used during the fourth sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10:8 MUX2 R/W 0 The MUX2 field is used during the third sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6:4 MUX1 R/W 0 The MUX1 field is used during the second sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. 3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2:0 MUX0 R/W 0 The MUX0 field is used during the first sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. June 14, 2007 277 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 22: ADC Sample Sequence Control 2 (ADCSSCTL2), offset 0x084 This register contains the configuration information for each sample for a sequence executed with Sample Sequencer 2. When configuring a sample sequence, the END bit must be set at some point, whether it be after the first sample, last sample, or any sample in between. This register is 16-bits wide and contains information for four possible samples. ADC Sample Sequence Control 2 (ADCSSCTL2) Base 0x4003.8000 Offset 0x084 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 TS3 IE3 END3 D3 TS2 IE2 END2 D2 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 TS1 IE1 END1 D1 TS0 IE0 END0 D0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset Type Reset Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15 TS3 R/W 0 Same definition as TS7 but used during the fourth sample. 14 IE3 R/W 0 Same definition as IE7 but used during the fourth sample. 13 END3 R/W 0 Same definition as END7 but used during the fourth sample. 12 D3 R/W 0 Same definition as D7 but used during the fourth sample. 11 TS2 R/W 0 Same definition as TS7 but used during the third sample. 10 IE2 R/W 0 Same definition as IE7 but used during the third sample. 9 END2 R/W 0 Same definition as END7 but used during the third sample. 8 D2 R/W 0 Same definition as D7 but used during the third sample. 7 TS1 R/W 0 Same definition as TS7 but used during the second sample. 6 IE1 R/W 0 Same definition as IE7 but used during the second sample. 5 END1 R/W 0 Same definition as END7 but used during the second sample. 4 D1 R/W 0 Same definition as D7 but used during the second sample. 3 TS0 R/W 0 Same definition as TS7 but used during the first sample. 2 IE0 R/W 0 Same definition as IE7 but used during the first sample. 1 END0 R/W 0 Same definition as END7 but used during the first sample. Since this sequencer has only one entry, this bit must be set. 0 D0 R/W 0 Same definition as D7 but used during the first sample. 278 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 23: ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3), offset 0x0A0 This register defines the analog input configuration for each sample in a sequence executed with Sample Sequencer 3. This register is 4-bits wide and contains information for one possible sample. ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3) Base 0x4003.8000 Offset 0x0A0 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 9 8 7 6 5 4 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 MUX0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2:0 MUX0 R/W 0 The MUX0 field is used during the first sample of a sequence executed with the Sample Sequencer and specifies which of the analog inputs is sampled for the analog-to-digital conversion. June 14, 2007 279 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 24: ADC Sample Sequence Control 3 (ADCSSCTL3), offset 0x0A4 This register contains the configuration information for each sample for a sequence executed with Sample Sequencer 3. The END bit is always set since there is only one sample in this sequencer. This register is 4-bits wide and contains information for one possible sample. ADC Sample Sequence Control 3 (ADCSSCTL3) Base 0x4003.8000 Offset 0x0A4 Type R/W, reset 0x0000.0002 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 TS0 IE0 END0 D0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TS0 R/W 0 Same definition as TS7 but used during the first sample. 2 IE0 R/W 0 Same definition as IE7 but used during the first sample. 1 END0 R/W 0 Same definition as END7 but used during the first sample. Since this sequencer has only one entry, this bit must be set. 0 D0 R/W 0 Same definition as D7 but used during the first sample. 280 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 25: ADC Sample Sequence Result FIFO 3 (ADCSSFIFO3), offset 0x0A8 This register contains the conversion results for samples collected with Sample Sequencer 3. Reads of this register return the conversion result data. If the FIFO is not properly handled by software, overflow and underflow conditions are registered in the ADCOSTAT and ADCUSTAT registers. Bit fields and definitions are the same as ADCSSFIFO0 (see page 273) but are for FIFO 3. June 14, 2007 281 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Register 26: ADC Sample Sequence FIFO 3 Status (ADCSSFSTAT3), offset 0x0AC This register provides a window into the Sample Sequencer FIFO 3, providing full/empty status information as well as the positions of the head and tail pointers. The reset value of 0x100 indicates an empty FIFO. This register has the same bit fields and definitions as ADCSSFSTAT0 (see page 274) but is for FIFO 3. 282 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 27: ADC Test Mode Loopback (ADCTMLB), offset 0x100 This register provides loopback operation within the digital logic of the ADC, which can be useful in debugging software without having to provide actual analog stimulus. This test mode is entered by writing a value of 0x0000.0001 to this register. When data is read from the FIFO in loopback mode, the read-only portion of this register is returned. Read-Only Register ADC Test Mode Loopback (ADCTMLB) Base 0x4003.8000 Offset 0x100 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 2 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CNT RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 5 4 3 CONT DIFF TS RO 0 RO 0 RO 0 MUX RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:10 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9:6 CNT RO 0 Continuous sample counter that is initialized to 0 and counts each sample as it processed. This helps provide a unique value for the data received. 5 CONT RO 0 When set, indicates that this is a continuation sample. For example if two sequencers were to run back-to-back, this indicates that the controller kept continuously sampling at full rate. 4 DIFF RO 0 When set, indicates that this is a differential sample. 3 TS RO 0 When set, indicates that this is a temperature sensor sample. 2:0 MUX RO 0 Indicates which analog input is to be sampled. Write-Only Register ADC Test Mode Loopback (ADCTMLB) Base 0x4003.8000 Offset 0x100 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 WO 0 reserved Type Reset reserved Type Reset RO 0 LB June 14, 2007 283 Luminary Micro Confidential-Advance Product Information Analog-to-Digital Converter (ADC) Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 LB WO 0 When set, forces a loopback within the digital block to provide information on input and unique numbering. The 10-bit loopback data is defined as shown in the read for bits 9:0 below. 284 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 13 Universal Asynchronous Receivers/Transmitters (UARTs) UART ® The Stellaris Universal Asynchronous Receiver/Transmitter (UART) provides fully programmable, 16C550-type serial interface characteristics. The LM3S8938 controller is equipped with three UART modules. Each UART has the following features: ■ Separate transmit and receive FIFOs ■ Programmable FIFO length, including 1-byte deep operation providing conventional double-buffered interface ■ FIFO trigger levels of 1/8, 1/4, 1/2, 3/4, and 7/8 ■ Programmable baud-rate generator allowing rates up to 460.8 Kbps ■ Standard asynchronous communication bits for start, stop and parity ■ False start bit detection ■ Line-break generation and detection ■ Fully programmable serial interface characteristics: – 5, 6, 7, or 8 data bits – Even, odd, stick, or no-parity bit generation/detection – 1 or 2 stop bit generation ■ IrDA serial-IR (SIR) encoder/decoder providing: – Programmable use of IrDA Serial InfraRed (SIR) or UART input/output – Support of IrDA SIR encoder/decoder functions for data rates up to 115.2 Kbps half-duplex – Support of normal 3/16 and low-power (1.41-2.23 μs) bit durations – Programmable internal clock generator enabling division of reference clock by 1 to 256 for low-power mode bit duration June 14, 2007 285 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) 13.1 Block Diagram Figure 13-1. UART Module Block Diagram System Clock Interrupt Control Interrupt TXFIFO 16x8 UARTIFLS UARTIM UARTMIS . . . UARTRIS Identification Registers UARTICR Transmitter UnTx Receiver UnRx UARTPCellID0 UARTPCellID1 UARTDR Baud Rate Generator UARTPCellID2 UARTIBRD UARTPCellID3 UARTFBRD UARTPeriphID0 UARTPeriphID1 UARTPeriphID2 UARTPeriphID3 Control / Status UART PeriphID4 UARTRSR/ECR UARTPeriphID5 RXFIFO 16x8 UARTFR UARTPeriphID6 UARTLCRH UARTPeriphID7 UARTCTL UARTILPR 13.2 . . . Functional Description ® Each Stellaris UART performs the functions of parallel-to-serial and serial-to-parallel conversions. It is similar in functionality to a 16C550 UART, but is not register compatible. The UART is configured for transmit and/or receive via the TXE and RXE bits of the UART Control (UARTCTL) register (see page 304). Transmit and receive are both enabled out of reset. Before any control registers are programmed, the UART must be disabled by clearing the UARTEN bit in UARTCTL. If the UART is disabled during a TX or RX operation, the current transaction is completed prior to the UART stopping. The UART peripheral also includes a serial IR (SIR) encoder/decoder block that can be connected to an infrared transceiver to implement an IrDA SIR physical layer. The SIR function is programmed using the UARTCTL register. 13.2.1 Transmit/Receive Logic The transmit logic performs parallel-to-serial conversion on the data read from the transmit FIFO. The control logic outputs the serial bit stream beginning with a start bit, and followed by the data 286 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller bits (LSB first), parity bit, and the stop bits according to the programmed configuration in the control registers. See Figure 13-2 on page 287 for details. The receive logic performs serial-to-parallel conversion on the received bit stream after a valid start pulse has been detected. Overrun, parity, frame error checking, and line-break detection are also performed, and their status accompanies the data that is written to the receive FIFO. Figure 13-2. UART Character Frame UnTX LSB 1 5-8 data bits 0 n Parity bit if enabled Start 13.2.2 1-2 stop bits MSB Baud-Rate Generation The baud-rate divisor is a 22-bit number consisting of a 16-bit integer and a 6-bit fractional part. The number formed by these two values is used by the baud-rate generator to determine the bit period. Having a fractional baud-rate divider allows the UART to generate all the standard baud rates. The 16-bit integer is loaded through the UART Integer Baud-Rate Divisor (UARTIBRD) register (see page 300) and the 6-bit fractional part is loaded with the UART Fractional Baud-Rate Divisor (UARTFBRD) register (see page 301). The baud-rate divisor (BRD) has the following relationship to the system clock (where BRDI is the integer part of the BRD and BRDF is the fractional part, separated by a decimal place.): BRD = BRDI + BRDF = SysClk / (16 * Baud Rate) The 6-bit fractional number (that is to be loaded into the DIVFRAC bit field in the UARTFBRD register) can be calculated by taking the fractional part of the baud-rate divisor, multiplying it by 64, and adding 0.5 to account for rounding errors: UARTFBRD[DIVFRAC] = integer(BRDF * 64 + 0.5) The UART generates an internal baud-rate reference clock at 16x the baud-rate (referred to as Baud16). This reference clock is divided by 16 to generate the transmit clock, and is used for error detection during receive operations. Along with the UART Line Control, High Byte (UARTLCRH) register (see page 302), the UARTIBRD and UARTFBRD registers form an internal 30-bit register. This internal register is only updated when a write operation to UARTLCRH is performed, so any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register for the changes to take effect. To update the baud-rate registers, there are four possible sequences: ■ UARTIBRD write, UARTFBRD write, and UARTLCRH write ■ UARTFBRD write, UARTIBRD write, and UARTLCRH write ■ UARTIBRD write and UARTLCRH write ■ UARTFBRD write and UARTLCRH write June 14, 2007 287 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) 13.2.3 Data Transmission Data received or transmitted is stored in two 16-byte FIFOs, though the receive FIFO has an extra four bits per character for status information. For transmission, data is written into the transmit FIFO. If the UART is enabled, it causes a data frame to start transmitting with the parameters indicated in the UARTLCRH register. Data continues to be transmitted until there is no data left in the transmit FIFO. The BUSY bit in the UART Flag (UARTFR) register (see page 297) is asserted as soon as data is written to the transmit FIFO (that is, if the FIFO is non-empty) and remains asserted while data is being transmitted. The BUSY bit is negated only when the transmit FIFO is empty, and the last character has been transmitted from the shift register, including the stop bits. The UART can indicate that it is busy even though the UART may no longer be enabled. When the receiver is idle (the UnRx is continuously 1) and the data input goes Low (a start bit has been received), the receive counter begins running and data is sampled on the eighth cycle of Baud16 (described in “Transmit/Receive Logic” on page 286). The start bit is valid if UnRx is still low on the eighth cycle of Baud16, otherwise a false start bit is detected and it is ignored. Start bit errors can be viewed in the UART Receive Status (UARTRSR) register (see page 295). If the start bit was valid, successive data bits are sampled on every 16th cycle of Baud16 (that is, one bit period later) according to the programmed length of the data characters. The parity bit is then checked if parity mode was enabled. Data length and parity are defined in the UARTLCRH register. Lastly, a valid stop bit is confirmed if UnRx is High, otherwise a framing error has occurred. When a full word is received, the data is stored in the receive FIFO, with any error bits associated with that word. 13.2.4 Serial IR (SIR) The UART peripheral includes an IrDA serial-IR (SIR) encoder/decoder block. The IrDA SIR block provides functionality that converts between an asynchronous UART data stream, and half-duplex serial SIR interface. No analog processing is performed on-chip. The role of the SIR block is to provide a digital encoded output, and decoded input to the UART. The UART signal pins can be connected to an infrared transceiver to implement an IrDA SIR physical layer link. The SIR block has two modes of operation: ■ In normal IrDA mode, a zero logic level is transmitted as high pulse of 3/16th duration of the selected baud rate bit period on the output pin, while logic one levels are transmitted as a static LOW signal. These levels control the driver of an infrared transmitter, sending a pulse of light for each zero. On the reception side, the incoming light pulses energize the photo transistor base of the receiver, pulling its output LOW. This drives the UART input pin LOW. ■ In low-power IrDA mode, the width of the transmitted infrared pulse is set to three times the period of the internally generated IrLPBaud16 signal (1.63 µs, assuming a nominal 1.8432 MHz frequency) by changing the appropriate bit in the UARTCR register. Figure 13-3 on page 289 shows the UART transmit and receive signals, with and without IrDA modulation. 288 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 13-3. IrDA Data Modulation Data bits Start bit UnTx 1 0 0 0 1 Stop bit 0 0 1 1 1 UnTx with IrDA 3 16 Bit period Bit period UnRx with IrDA UnRx 0 1 0 1 Start 0 0 1 1 0 Data bits 1 Stop In both normal and low-power IrDA modes: ■ During transmission, the UART data bit is used as the base for encoding ■ During reception, the decoded bits are transferred to the UART receive logic The IrDA SIR physical layer specifies a half-duplex communication link, with a minimum 10 ms delay between transmission and reception. This delay must be generated by software because it is not automatically supported by the UART. The delay is required because the infrared receiver electronics might become biased, or even saturated from the optical power coupled from the adjacent transmitter LED. This delay is known as latency, or receiver setup time. 13.2.5 FIFO Operation The UART has two 16-entry FIFOs; one for transmit and one for receive. Both FIFOs are accessed via the UART Data (UARTDR) register (see page 293). Read operations of the UARTDR register return a 12-bit value consisting of 8 data bits and 4 error flags while write operations place 8-bit data in the transmit FIFO. Out of reset, both FIFOs are disabled and act as 1-byte-deep holding registers. The FIFOs are enabled by setting the FEN bit in UARTLCRH (page 302). FIFO status can be monitored via the UART Flag (UARTFR) register (see page 297) and the UART Receive Status (UARTRSR) register. Hardware monitors empty, full and overrun conditions. The UARTFR register contains empty and full flags (TXFE, TXFF, RXFE and RXFF bits) and the UARTRSR register shows overrun status via the OE bit. The trigger points at which the FIFOs generate interrupts is controlled via the UART Interrupt FIFO Level Select (UARTIFLS) register (see page 306). Both FIFOs can be individually configured to trigger interrupts at different levels. Available configurations include 1/8, ¼, ½, ¾, and 7/8. For example, if the ¼ option is selected for the receive FIFO, the UART generates a receive interrupt after 4 data bytes are received. Out of reset, both FIFOs are configured to trigger an interrupt at the ½ mark. 13.2.6 Interrupts The UART can generate interrupts when the following conditions are observed: ■ Overrun Error ■ Break Error June 14, 2007 289 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) ■ Parity Error ■ Framing Error ■ Receive Timeout ■ Transmit (when condition defined in the TXIFLSEL bit in the UARTIFLS register is met) ■ Receive (when condition defined in the RXIFLSEL bit in the UARTIFLS register is met) All of the interrupt events are ORed together before being sent to the interrupt controller, so the UART can only generate a single interrupt request to the controller at any given time. Software can service multiple interrupt events in a single interrupt service routine by reading the UART Masked Interrupt Status (UARTMIS) register (see page 310). The interrupt events that can trigger a controller-level interrupt are defined in the UART Interrupt Mask (UARTIM ) register (see page 307) by setting the corresponding IM bit to 1. If interrupts are not used, the raw interrupt status is always visible via the UART Raw Interrupt Status (UARTRIS) register (see page 309). Interrupts are always cleared (for both the UARTMIS and UARTRIS registers) by setting the corresponding bit in the UART Interrupt Clear (UARTICR) register (see page 311). 13.2.7 Loopback Operation The UART can be placed into an internal loopback mode for diagnostic or debug work. This is accomplished by setting the LBE bit in the UARTCTL register (see page 304). In loopback mode, data transmitted on UnTx is received on the UnRx input. 13.2.8 IrDA SIR block The IrDA SIR block contains an IrDA serial IR (SIR) protocol encoder/decoder. When enabled, the SIR block uses the UnTx and UnRx pins for the SIR protocol, which should be connected to an IR transceiver. The SIR block can receive and transmit, but it is only half-duplex so it cannot do both at the same time. Transmission must be stopped before data can be received. The IrDA SIR physcial layer specifies a minimum 10-ms delay between transmission and reception. 13.3 Initialization and Configuration To use the UARTs, the peripheral clock must be enabled by setting the UART0, UART1, or UART2 bits in the RCGC1 register. This section discusses the steps that are required for using a UART module. For this example, the system clock is assumed to be 20 MHz and the desired UART configuration is: ■ 115200 baud rate ■ Data length of 8 bits ■ One stop bit ■ No parity ■ FIFOs disabled 290 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller ■ No interrupts The first thing to consider when programming the UART is the baud-rate divisor (BRD), since the UARTIBRD and UARTFBRD registers must be written before the UARTLCRH register. Using the equation described in “Baud-Rate Generation” on page 287, the BRD can be calculated: BRD = 20,000,000 / (16 * 115,200) = 10.8507 which means that the DIVINT field of the UARTIBRD register (see page 300) should be set to 10. The value to be loaded into the UARTFBRD register (see page 301) is calculated by the equation: UARTFBRD[DIVFRAC] = integer(0.8507 * 64 + 0.5) = 54 With the BRD values in hand, the UART configuration is written to the module in the following order: 1. Disable the UART by clearing the UARTEN bit in the UARTCTL register. 2. Write the integer portion of the BRD to the UARTIBRD register. 3. Write the fractional portion of the BRD to the UARTFBRD register. 4. Write the desired serial parameters to the UARTLCRH register (in this case, a value of 0x0000.0060). 5. Enable the UART by setting the UARTEN bit in the UARTCTL register. 13.4 Register Map Table 13-1 on page 291 lists the UART registers. The offset listed is a hexadecimal increment to the register’s address, relative to that UART’s base address: ■ UART0: 0x4000.C000 ■ UART1: 0x4000.D000 ■ UART2: 0x4000.E000 Note: The UART must be disabled (see the UARTEN bit in the UARTCTL register on page 304) before any of the control registers are reprogrammed. When the UART is disabled during a TX or RX operation, the current transaction is completed prior to the UART stopping. Table 13-1. UART Register Map Type Reset Description See page UARTDR RO 0x0000.0000 UART Data 293 0x004 UARTRSR/UARTECR R/W 0x0000.0000 UART Receive Status/Error Clear 295 0x018 UARTFR RO 0x0000.0090 UART Flag 297 0x020 UARTILPR R/W 0x0000.0000 UART IrDA Low-Power Register 299 0x024 UARTIBRD R/W 0x0000.0000 UART Integer Baud-Rate Divisor 300 0x028 UARTFBRD R/W 0x0000.0000 UART Fractional Baud-Rate Divisor 301 Offset Name 0x000 June 14, 2007 291 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Name Type Reset 0x02C UARTLCRH R/W 0x0000.0000 UART Line Control 302 0x030 UARTCTL R/W 0x0000.0300 UART Control 304 0x034 UARTIFLS R/W 0x0000.0012 UART Interrupt FIFO Level Select 306 0x038 UARTIM R/W 0x0000.0000 UART Interrupt Mask 307 0x03C UARTRIS RO 0x0000.000F UART Raw Interrupt Status 309 0x040 UARTMIS RO 0x0000.0000 UART Masked Interrupt Status 310 0x044 UARTICR W1C 0x0000.0000 UART Interrupt Clear 311 0xFD0 UARTPeriphID4 RO 0x0000.0000 UART Peripheral Identification 4 313 0xFD4 UARTPeriphID5 RO 0x0000.0000 UART Peripheral Identification 5 314 0xFD8 UARTPeriphID6 RO 0x0000.0000 UART Peripheral Identification 6 315 0xFDC UARTPeriphID7 RO 0x0000.0000 UART Peripheral Identification 7 316 0xFE0 UARTPeriphID0 RO 0x0000.0011 UART Peripheral Identification 0 317 0xFE4 UARTPeriphID1 RO 0x0000.0000 UART Peripheral Identification 1 318 0xFE8 UARTPeriphID2 RO 0x0000.0018 UART Peripheral Identification 2 319 0xFEC UARTPeriphID3 RO 0x0000.0001 UART Peripheral Identification 3 320 0xFF0 UARTPCellID0 RO 0x0000.000D UART PrimeCell Identification 0 321 0xFF4 UARTPCellID1 RO 0x0000.00F0 UART PrimeCell Identification 1 322 0xFF8 UARTPCellID2 RO 0x0000.0005 UART PrimeCell Identification 2 323 0xFFC UARTPCellID3 RO 0x0000.00B1 UART PrimeCell Identification 3 324 13.5 Description See page Offset Register Descriptions The remainder of this section lists and describes the UART registers, in numerical order by address offset. 292 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 1: UART Data (UARTDR), offset 0x000 This register is the data register (the interface to the FIFOs). When FIFOs are enabled, data written to this location is pushed onto the transmit FIFO. If FIFOs are disabled, data is stored in the transmitter holding register (the bottom word of the transmit FIFO). A write to this register initiates a transmission from the UART. For received data, if the FIFO is enabled, the data byte and the 4-bit status (break, frame, parity and overrun) is pushed onto the 12-bit wide receive FIFO. If FIFOs are disabled, the data byte and status are stored in the receiving holding register (the bottom word of the receive FIFO). The received data can be retrieved by reading this register. UART Data (UARTDR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x000 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 OE BE PE FE RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 DATA Bit/Field Name Type Reset Description 31:12 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 11 OE RO 0 UART Overrun Error 1=New data was received when the FIFO was full, resulting in data loss. 0=There has been no data loss due to a FIFO overrun. 10 BE RO 0 UART Break Error This bit is set to 1 when a break condition is detected, indicating that the receive data input was held Low for longer than a full-word transmission time (defined as start, data, parity, and stop bits). In FIFO mode, this error is associated with the character at the top of the FIFO. When a break occurs, only one 0 character is loaded into the FIFO. The next character is only enabled after the received data input goes to a 1 (marking state) and the next valid start bit is received. 9 PE RO 0 UART Parity Error This bit is set to 1 when the parity of the received data character does not match the parity defined by bits 2 and 7 of the UARTLCRH register. In FIFO mode, this error is associated with the character at the top of the FIFO. June 14, 2007 293 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 8 FE RO 0 Description UART Framing Error This bit is set to 1 when the received character does not have a valid stop bit (a valid stop bit is 1). 7:0 DATA R/W 0 When written, the data that is to be transmitted via the UART. When read, the data that was received by the UART. 294 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: UART Receive Status/Error Clear (UARTRSR/UARTECR), offset 0x004 The UARTRSR/UARTECR register is the receive status register/error clear register. In addition to the UARTDR register, receive status can also be read from the UARTRSR register. If the status is read from this register, then the status information corresponds to the entry read from UARTDR prior to reading UARTRSR. The status information for overrun is set immediately when an overrun condition occurs. A write of any value to the UARTECR register clears the framing, parity, break, and overrun errors. All the bits are cleared to 0 on reset. Read-Only Receive Status (UARTRSR) Register UART Receive Status/Error Clear (UARTRSR/UARTECR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x004 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 OE BE PE FE RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:4 reserved RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. The UARTRSR register cannot be written. 3 OE RO 0 UART Overrun Error When this bit is set to 1, data is received and the FIFO is already full. This bit is cleared to 0 by a write to UARTECR. The FIFO contents remain valid since no further data is written when the FIFO is full, only the contents of the shift register are overwritten. The CPU must now read the data in order to empty the FIFO. 2 BE RO 0 UART Break Error This bit is set to 1 when a break condition is detected, indicating that the received data input was held Low for longer than a full-word transmission time (defined as start, data, parity, and stop bits). This bit is cleared to 0 by a write to UARTECR. In FIFO mode, this error is associated with the character at the top of the FIFO. When a break occurs, only one 0 character is loaded into the FIFO. The next character is only enabled after the receive data input goes to a 1 (marking state) and the next valid start bit is received. June 14, 2007 295 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 1 PE RO 0 Description UART Parity Error This bit is set to 1 when the parity of the received data character does not match the parity defined by bits 2 and 7 of the UARTLCRH register. This bit is cleared to 0 by a write to UARTECR. 0 FE RO 0 UART Framing Error This bit is set to 1 when the received character does not have a valid stop bit (a valid stop bit is 1). This bit is cleared to 0 by a write to UARTECR. In FIFO mode, this error is associated with the character at the top of the FIFO. Write-Only Error Clear (UARTECR) Register UART Receive Status/Error Clear (UARTRSR/UARTECR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x004 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 15 14 13 12 11 10 9 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 23 22 21 20 19 18 17 16 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 8 7 6 5 4 3 2 1 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 WO 0 reserved Type Reset reserved Type Reset DATA WO 0 Bit/Field Name Type Reset Description 31:8 reserved WO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 DATA WO 0 A write to this register of any data clears the framing, parity, break and overrun flags. 296 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 3: UART Flag (UARTFR), offset 0x018 The UARTFR register is the flag register. After reset, the TXFF, RXFF, and BUSY bits are 0, and TXFE and RXFE bits are 1. UART Flag (UARTFR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x018 Type RO, reset 0x0000.0090 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 TXFE RXFF TXFF RXFE BUSY RO 1 RO 0 RO 0 RO 1 RO 0 reserved Type Reset reserved Type Reset RO 0 reserved RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7 TXFE RO 1 UART Transmit FIFO Empty The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. If the FIFO is disabled (FEN is 0), this bit is set when the transmit holding register is empty. If the FIFO is enabled (FEN is 1), this bit is set when the transmit FIFO is empty. 6 RXFF RO 0 UART Receive FIFO Full The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. If the FIFO is disabled, this bit is set when the receive holding register is full. If the FIFO is enabled, this bit is set when the receive FIFO is full. 5 TXFF RO 0 UART Transmit FIFO Full The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. If the FIFO is disabled, this bit is set when the transmit holding register is full. If the FIFO is enabled, this bit is set when the transmit FIFO is full. June 14, 2007 297 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 4 RXFE RO 1 Description UART Receive FIFO Empty The meaning of this bit depends on the state of the FEN bit in the UARTLCRH register. If the FIFO is disabled, this bit is set when the receive holding register is empty. If the FIFO is enabled, this bit is set when the receive FIFO is empty. 3 BUSY RO 0 UART Busy When this bit is 1, the UART is busy transmitting data. This bit remains set until the complete byte, including all stop bits, has been sent from the shift register. This bit is set as soon as the transmit FIFO becomes non-empty (regardless of whether UART is enabled). 2:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 298 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 4: UART IrDA Low-Power Register (UARTILPR), offset 0x020 The UARTILPR register is an 8-bit read/write register that stores the low-power counter divisor value used to generate the IrLPBaud16 signal by dividing down the system clock (SysClk). All the bits are cleared to 0 when reset. The IrLPBaud16 internal signal is generated by dividing down the UARTCLK signal according to the low-power divisor value written to UARTILPR. The low-power divisor value is calculated as follows: ILPDVSR = SysClk / FIrLPBaud16 where FIrLPBaud16 is nominally 1.8432 MHz. IrLPBaud16 is an internal signal used for SIR pulse generation when low-power mode is used. You must choose the divisor so that 1.42 MHz < FIrLPBaud16 < 2.12 MHz, which results in a low-power pulse duration of 1.41–2.11 μs (three times the period of IrLPBaud16). The minimum frequency of IrLPBaud16 ensures that pulses less than one period of IrLPBaud16 are rejected, but that pulses greater than 1.4 μs are accepted as valid pulses. Note: Zero is an illegal value. Programming a zero value results in no IrLPBaud16 pulses being generated. UART IrDA Low-Power Register (UARTILPR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x020 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset ILPDVSR RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 ILPDVSR R/W 0x0000 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. IrDA Low-Power Divisor This is an 8-bit low-power divisor value. June 14, 2007 299 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 5: UART Integer Baud-Rate Divisor (UARTIBRD), offset 0x024 The UARTIBRD register is the integer part of the baud-rate divisor value. All the bits are cleared on reset. The minimum possible divide ratio is 1 (when UARTIBRD=0), in which case the UARTFBRD register is ignored. When changing the UARTIBRD register, the new value does not take effect until transmission/reception of the current character is complete. Any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register. See “Baud-Rate Generation” on page 287 for configuration details. UART Integer Baud-Rate Divisor (UARTIBRD) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x024 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset DIVINT Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0 15:0 DIVINT R/W 0x0000 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Integer Baud-Rate Divisor 300 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: UART Fractional Baud-Rate Divisor (UARTFBRD), offset 0x028 The UARTFBRD register is the fractional part of the baud-rate divisor value. All the bits are cleared on reset. When changing the UARTFBRD register, the new value does not take effect until transmission/reception of the current character is complete. Any changes to the baud-rate divisor must be followed by a write to the UARTLCRH register. See “Baud-Rate Generation” on page 287 for configuration details. UART Fractional Baud-Rate Divisor (UARTFBRD) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x028 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset DIVFRAC RO 0 Bit/Field Name Type Reset 31:6 reserved RO 0 5:0 DIVFRAC R/W 0x00 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Fractional Baud-Rate Divisor June 14, 2007 301 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 7: UART Line Control (UARTLCRH), offset 0x02C The UARTLCRH register is the line control register. Serial parameters such as data length, parity and stop bit selection are implemented in this register. When updating the baud-rate divisor (UARTIBRD and/or UARTIFRD), the UARTLCRH register must also be written. The write strobe for the baud-rate divisor registers is tied to the UARTLCRH register. UART Line Control (UARTLCRH) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x02C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 reserved Type Reset RO 0 RO 0 RO 0 RO 0 SPS RO 0 RO 0 RO 0 RO 0 R/W 0 5 WLEN R/W 0 R/W 0 4 3 2 1 0 FEN STP2 EPS PEN BRK R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7 SPS R/W 0 UART Stick Parity Select When bits 1, 2 and 7 of UARTLCRH are set, the parity bit is transmitted and checked as a 0. When bits 1 and 7 are set and 2 is cleared, the parity bit is transmitted and checked as a 1. When this bit is cleared, stick parity is disabled. 6:5 WLEN R/W 0 UART Word Length The bits indicate the number of data bits transmitted or received in a frame as follows: 0x3: 8 bits 0x2: 7 bits 0x1: 6 bits 0x0: 5 bits (default) 4 FEN R/W 0 UART Enable FIFOs If this bit is set to 1, transmit and receive FIFO buffers are enabled (FIFO mode). When cleared to 0, FIFOs are disabled (Character mode). The FIFOs become 1-byte-deep holding registers. 3 STP2 R/W 0 UART Two Stop Bits Select If this bit is set to 1, two stop bits are transmitted at the end of a frame. The receive logic does not check for two stop bits being received. 302 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 2 EPS R/W 0 Description UART Even Parity Select If this bit is set to 1, even parity generation and checking is performed during transmission and reception, which checks for an even number of 1s in data and parity bits. When cleared to 0, then odd parity is performed, which checks for an odd number of 1s. This bit has no effect when parity is disabled by the PEN bit. 1 PEN R/W 0 UART Parity Enable If this bit is set to 1, parity checking and generation is enabled; otherwise, parity is disabled and no parity bit is added to the data frame. 0 BRK R/W 0 UART Send Break If this bit is set to 1, a Low level is continually output on the UnTX output, after completing transmission of the current character. For the proper execution of the break command, the software must set this bit for at least two frames (character periods). For normal use, this bit must be cleared to 0. June 14, 2007 303 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 8: UART Control (UARTCTL), offset 0x030 The UARTCTL register is the control register. All the bits are cleared on reset except for the Transmit Enable (TXE) and Receive Enable (RXE) bits, which are set to 1. To enable the UART module, the UARTEN bit must be set to 1. If software requires a configuration change in the module, the UARTEN bit must be cleared before the configuration changes are written. If the UART is disabled during a transmit or receive operation, the current transaction is completed prior to the UART stopping. UART Control (UARTCTL) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x030 Type R/W, reset 0x0000.0300 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 6 5 4 3 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 9 8 7 RXE TXE LBE R/W 1 R/W 1 R/W 0 reserved RO 0 RO 0 RO 0 RO 0 2 1 0 SIRLP SIREN UARTEN R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:10 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9 RXE R/W 1 UART Receive Enable If this bit is set to 1, the receive section of the UART is enabled. When the UART is disabled in the middle of a receive, it completes the current character before stopping. Note: 8 TXE R/W 1 To enable reception, the UARTEN bit must also be set. UART Transmit Enable If this bit is set to 1, the transmit section of the UART is enabled. When the UART is disabled in the middle of a transmission, it completes the current character before stopping. Note: 7 LBE R/W 0 To enable transmission, the UARTEN bit must also be set. UART Loop Back Enable If this bit is set to 1, the UnTX path is fed through the UnRX path. 6:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 304 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 2 SIRLP R/W 0 Description UART SIR Low Power Mode This bit selects the IrDA encoding mode. If this bit is cleared to 0, low-level bits are transmitted as an active High pulse with a width of 3/16th of the bit period. If this bit is set to 1, low-level bits are transmitted with a pulse width which is 3 times the period of the IrLPBaud16 input signal, regardless of the selected bit rate. Setting this bit uses less power, but might reduce transmission distances. See page 299 for more information. 1 SIREN R/W 0 UART SIR Enable If this bit is set to 1, the IrDA SIR block is enabled, and the UART will transmit and receive data using SIR protocol. 0 UARTEN R/W 0 UART Enable If this bit is set to 1, the UART is enabled. When the UART is disabled in the middle of transmission or reception, it completes the current character before stopping. June 14, 2007 305 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 9: UART Interrupt FIFO Level Select (UARTIFLS), offset 0x034 The UARTIFLS register is the interrupt FIFO level select register. You can use this register to define the FIFO level at which the TXRIS and RXRIS bits in the UARTRIS register are triggered. The interrupts are generated based on a transition through a level rather than being based on the level. That is, the interrupts are generated when the fill level progresses through the trigger level. For example, if the receive trigger level is set to the half-way mark, the interrupt is triggered as the module is receiving the 9th character. Out of reset, the TXIFLSEL and RXIFLSEL bits are configured so that the FIFOs trigger an interrupt at the half-way mark. UART Interrupt FIFO Level Select (UARTIFLS) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x034 Type R/W, reset 0x0000.0012 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset RXIFLSEL RO 0 Bit/Field Name Type Reset 31:6 reserved RO 0 5:3 RXIFLSEL R/W 0x2 R/W 1 TXIFLSEL R/W 1 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Receive Interrupt FIFO Level Select The trigger points for the receive interrupt are as follows: 000: RX FIFO ≥ 1/8 full 001: RX FIFO ≥ ¼ full 010: RX FIFO ≥ ½ full (default) 011: RX FIFO ≥ ¾ full 100: RX FIFO ≥ 7/8 full 101-111: Reserved 2:0 TXIFLSEL R/W 0x2 UART Transmit Interrupt FIFO Level Select The trigger points for the transmit interrupt are as follows: 000: TX FIFO ≤ 1/8 full 001: TX FIFO ≤ ¼ full 010: TX FIFO ≤ ½ full (default) 011: TX FIFO ≤ ¾ full 100: TX FIFO ≤ 7/8 full 101-111: Reserved 306 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 10: UART Interrupt Mask (UARTIM), offset 0x038 The UARTIM register is the interrupt mask set/clear register. On a read, this register gives the current value of the mask on the relevant interrupt. Writing a 1 to a bit allows the corresponding raw interrupt signal to be routed to the interrupt controller. Writing a 0 prevents the raw interrupt signal from being sent to the interrupt controller. UART Interrupt Mask (UARTIM) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x038 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 1 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 15 14 RO 0 RO 0 RO 0 13 12 11 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 4 OEIM BEIM PEIM FEIM RTIM TXIM RXIM R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved RO 0 RO 0 Bit/Field Name Type Reset Description 31:11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 OEIM R/W 0 UART Overrun Error Interrupt Mask On a read, the current mask for the OEIM interrupt is returned. Setting this bit to 1 promotes the OEIM interrupt to the interrupt controller. 9 BEIM R/W 0 UART Break Error Interrupt Mask On a read, the current mask for the BEIM interrupt is returned. Setting this bit to 1 promotes the BEIM interrupt to the interrupt controller. 8 PEIM R/W 0 UART Parity Error Interrupt Mask On a read, the current mask for the PEIM interrupt is returned. Setting this bit to 1 promotes the PEIM interrupt to the interrupt controller. 7 FEIM R/W 0 UART Framing Error Interrupt Mask On a read, the current mask for the FEIM interrupt is returned. Setting this bit to 1 promotes the FEIM interrupt to the interrupt controller. 6 RTIM R/W 0 UART Receive Time-Out Interrupt Mask On a read, the current mask for the RTIM interrupt is returned. Setting this bit to 1 promotes the RTIM interrupt to the interrupt controller. 5 TXIM R/W 0 UART Transmit Interrupt Mask On a read, the current mask for the TXIM interrupt is returned. Setting this bit to 1 promotes the TXIM interrupt to the interrupt controller. June 14, 2007 307 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 4 RXIM R/W 0 Description UART Receive Interrupt Mask On a read, the current mask for the RXIM interrupt is returned. Setting this bit to 1 promotes the RXIM interrupt to the interrupt controller. 3:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 308 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 11: UART Raw Interrupt Status (UARTRIS), offset 0x03C The UARTRIS register is the raw interrupt status register. On a read, this register gives the current raw status value of the corresponding interrupt. A write has no effect. UART Raw Interrupt Status (UARTRIS) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x03C Type RO, reset 0x0000.000F 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 OERIS RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 BERIS PERIS FERIS RTRIS TXRIS RXRIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 1 RO 1 reserved Type Reset reserved Type Reset RO 0 reserved Bit/Field Name Type Reset Description 31:11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 OERIS RO 0 UART Overrun Error Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt. 9 BERIS RO 0 UART Break Error Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt. 8 PERIS RO 0 UART Parity Error Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt. 7 FERIS RO 0 UART Framing Error Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt. 6 RTRIS RO 0 UART Receive Time-Out Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt. 5 TXRIS RO 0 UART Transmit Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt. 4 RXRIS RO 0 UART Receive Raw Interrupt Status Gives the raw interrupt state (prior to masking) of this interrupt. 3:0 reserved RO 0xF Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 309 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 12: UART Masked Interrupt Status (UARTMIS), offset 0x040 The UARTMIS register is the masked interrupt status register. On a read, this register gives the current masked status value of the corresponding interrupt. A write has no effect. UART Masked Interrupt Status (UARTMIS) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x040 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 OEMIS RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 BEMIS PEMIS FEMIS RTMIS TXMIS RXMIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 reserved Bit/Field Name Type Reset Description 31:11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 OEMIS RO 0 UART Overrun Error Masked Interrupt Status Gives the masked interrupt state of this interrupt. 9 BEMIS RO 0 UART Break Error Masked Interrupt Status Gives the masked interrupt state of this interrupt. 8 PEMIS RO 0 UART Parity Error Masked Interrupt Status Gives the masked interrupt state of this interrupt. 7 FEMIS RO 0 UART Framing Error Masked Interrupt Status Gives the masked interrupt state of this interrupt. 6 RTMIS RO 0 UART Receive Time-Out Masked Interrupt Status Gives the masked interrupt state of this interrupt. 5 TXMIS RO 0 UART Transmit Masked Interrupt Status Gives the masked interrupt state of this interrupt. 4 RXMIS RO 0 UART Receive Masked Interrupt Status Gives the masked interrupt state of this interrupt. 3:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 310 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 13: UART Interrupt Clear (UARTICR), offset 0x044 The UARTICR register is the interrupt clear register. On a write of 1, the corresponding interrupt (both raw interrupt and masked interrupt, if enabled) is cleared. A write of 0 has no effect. UART Interrupt Clear (UARTICR) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0x044 Type W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 OEIC RO 0 RO 0 RO 0 RO 0 W1C 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 BEIC PEIC FEIC RTIC TXIC RXIC W1C 0 W1C 0 W1C 0 W1C 0 W1C 0 W1C 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 reserved Bit/Field Name Type Reset Description 31:11 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 10 OEIC W1C 0 Overrun Error Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt. 9 BEIC W1C 0 Break Error Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt. 8 PEIC W1C 0 Parity Error Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt. 7 FEIC W1C 0 Framing Error Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt. 6 RTIC W1C 0 Receive Time-Out Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt. 5 TXIC W1C 0 Transmit Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt. June 14, 2007 311 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Bit/Field Name Type Reset 4 RXIC W1C 0 Description Receive Interrupt Clear 0: No effect on the interrupt. 1: Clears interrupt. 3:0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 312 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 14: UART Peripheral Identification 4 (UARTPeriphID4), offset 0xFD0 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 4 (UARTPeriphID4) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFD0 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID4 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID4 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register[7:0] June 14, 2007 313 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 15: UART Peripheral Identification 5 (UARTPeriphID5), offset 0xFD4 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 5 (UARTPeriphID5) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFD4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID5 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID5 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register[15:8] 314 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 16: UART Peripheral Identification 6 (UARTPeriphID6), offset 0xFD8 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 6 (UARTPeriphID6) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFD8 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID6 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID6 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register[23:16] June 14, 2007 315 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 17: UART Peripheral Identification 7 (UARTPeriphID7), offset 0xFDC The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 7 (UARTPeriphID7) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFDC Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID7 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID7 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register[31:24] 316 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 18: UART Peripheral Identification 0 (UARTPeriphID0), offset 0xFE0 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 0 (UARTPeriphID0) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFE0 Type RO, reset 0x0000.0011 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 0 RO 0 RO 1 reserved Type Reset reserved Type Reset PID0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID0 RO 0x11 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register[7:0] Can be used by software to identify the presence of this peripheral. June 14, 2007 317 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 19: UART Peripheral Identification 1 (UARTPeriphID1), offset 0xFE4 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 1 (UARTPeriphID1) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFE4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID1 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID1 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register[15:8] Can be used by software to identify the presence of this peripheral. 318 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 20: UART Peripheral Identification 2 (UARTPeriphID2), offset 0xFE8 The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 2 (UARTPeriphID2) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFE8 Type RO, reset 0x0000.0018 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID2 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID2 RO 0x18 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register[23:16] Can be used by software to identify the presence of this peripheral. June 14, 2007 319 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 21: UART Peripheral Identification 3 (UARTPeriphID3), offset 0xFEC The UARTPeriphIDn registers are hard-coded and the fields within the registers determine the reset values. UART Peripheral Identification 3 (UARTPeriphID3) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFEC Type RO, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset reserved Type Reset PID3 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID3 RO 0x01 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART Peripheral ID Register[31:24] Can be used by software to identify the presence of this peripheral. 320 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 22: UART PrimeCell Identification 0 (UARTPCellID0), offset 0xFF0 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values. UART PrimeCell Identification 0 (UARTPCellID0) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFF0 Type RO, reset 0x0000.000D 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 0 RO 1 reserved Type Reset reserved Type Reset CID0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID0 RO 0x0D Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART PrimeCell ID Register[7:0] Provides software a standard cross-peripheral identification system. June 14, 2007 321 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 23: UART PrimeCell Identification 1 (UARTPCellID1), offset 0xFF4 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values. UART PrimeCell Identification 1 (UARTPCellID1) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFF4 Type RO, reset 0x0000.00F0 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 1 RO 1 RO 1 RO 1 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset CID1 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID1 RO 0xF0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART PrimeCell ID Register[15:8] Provides software a standard cross-peripheral identification system. 322 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 24: UART PrimeCell Identification 2 (UARTPCellID2), offset 0xFF8 The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values. UART PrimeCell Identification 2 (UARTPCellID2) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFF8 Type RO, reset 0x0000.0005 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 1 reserved Type Reset reserved Type Reset CID2 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID2 RO 0x05 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART PrimeCell ID Register[23:16] Provides software a standard cross-peripheral identification system. June 14, 2007 323 Luminary Micro Confidential-Advance Product Information Universal Asynchronous Receivers/Transmitters (UARTs) Register 25: UART PrimeCell Identification 3 (UARTPCellID3), offset 0xFFC The UARTPCellIDn registers are hard-coded and the fields within the registers determine the reset values. UART PrimeCell Identification 3 (UARTPCellID3) UART0 base: 0x4000.C000 UART1 base: 0x4000.D000 UART2 base: 0x4000.E000 Offset 0xFFC Type RO, reset 0x0000.00B1 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 1 RO 0 RO 1 RO 1 RO 0 RO 0 RO 0 RO 1 reserved Type Reset reserved Type Reset CID3 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID3 RO 0xB1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. UART PrimeCell ID Register[31:24] Provides software a standard cross-peripheral identification system. 324 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 14 Synchronous Serial Interface (SSI) SSI ® The Stellaris Synchronous Serial Interface (SSI) is a master or slave interface for synchronous serial communication with peripheral devices that have either Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces. ® The Stellaris SSI module has the following features: ■ Master or slave operation ■ Programmable clock bit rate and prescale ■ Separate transmit and receive FIFOs, 16 bits wide, 8 locations deep ■ Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments synchronous serial interfaces ■ Programmable data frame size from 4 to 16 bits ■ Internal loopback test mode for diagnostic/debug testing 14.1 Block Diagram Figure 14-1. SSI Module Block Diagram Interrupt Interrupt Control SSIIM SSIMIS Control / Status SSIRIS SSIICR SSICR0 SSICR1 TxFIFO 8 x 16 . . . SSITx SSISR SSIDR RxFIFO 8 x 16 SSIRx Transmit/ Receive Logic SSIClk SSIFss System Clock Clock Prescaler Identification Registers SSIPCellID0 SSIPeriphID0 SSIPeriphID4 SSIPCellID1 SSIPeriphID1 SSIPeriphID5 SSIPCellID2 SSIPeriphID2 SSIPeriphID6 SSIPCellID3 SSIPeriphID3 SSIPeriphID7 . . . SSICPSR June 14, 2007 325 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) 14.2 Functional Description The SSI performs serial-to-parallel conversion on data received from a peripheral device. The CPU accesses data, control, and status information. The transmit and receive paths are buffered with internal FIFO memories allowing up to eight 16-bit values to be stored independently in both transmit and receive modes. 14.2.1 Bit Rate Generation The SSI includes a programmable bit rate clock divider and prescaler to generate the serial output clock. Bit rates are supported to 2 MHz and higher, although maximum bit rate is determined by peripheral devices. The serial bit rate is derived by dividing down the 50-MHz input clock. The clock is first divided by an even prescale value CPSDVSR from 2 to 254, which is programmed in the SSI Clock Prescale (SSICPSR) register (see page 342). The clock is further divided by a value from 1 to 256, which is 1 + SCR, where SCR is the value programmed in the SSI Control0 (SSICR0) register (see page 337). The frequency of the output clock SSIClk is defined by: FSSIClk = FSysClk / (CPSDVSR * (1 + SCR)) Note that although the SSIClk transmit clock can theoretically be 25 MHz, the module may not be able to operate at that speed. For master mode, the system clock must be at least two times faster than the SSIClk. For slave mode, the system clock must be at least 12 times faster than the SSIClk. See “Electrical Characteristics” on page 511 to view SSI timing parameters. 14.2.2 FIFO Operation 14.2.2.1 Transmit FIFO The common transmit FIFO is a 16-bit wide, 8-locations deep, first-in, first-out memory buffer. The CPU writes data to the FIFO by writing the SSI Data (SSIDR) register (see page 340), and data is stored in the FIFO until it is read out by the transmission logic. When configured as a master or a slave, parallel data is written into the transmit FIFO prior to serial conversion and transmission to the attached slave or master, respectively, through the SSITx pin. 14.2.2.2 Receive FIFO The common receive FIFO is a 16-bit wide, 8-locations deep, first-in, first-out memory buffer. Received data from the serial interface is stored in the buffer until read out by the CPU, which accesses the read FIFO by reading the SSIDR register. When configured as a master or slave, serial data received through the SSIRx pin is registered prior to parallel loading into the attached slave or master receive FIFO, respectively. 14.2.3 Interrupts The SSI can generate interrupts when the following conditions are observed: ■ Transmit FIFO service ■ Receive FIFO service ■ Receive FIFO time-out 326 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller ■ Receive FIFO overrun All of the interrupt events are ORed together before being sent to the interrupt controller, so the SSI can only generate a single interrupt request to the controller at any given time. You can mask each of the four individual maskable interrupts by setting the appropriate bits in the SSI Interrupt Mask (SSIIM) register (see page 343). Setting the appropriate mask bit to 1 enables the interrupt. Provision of the individual outputs, as well as a combined interrupt output, allows use of either a global interrupt service routine, or modular device drivers to handle interrupts. The transmit and receive dynamic dataflow interrupts have been separated from the status interrupts so that data can be read or written in response to the FIFO trigger levels. The status of the individual interrupt sources can be read from the SSI Raw Interrupt Status (SSIRIS) and SSI Masked Interrupt Status (SSIMIS) registers (see page 344 and page 345, respectively). 14.2.4 Frame Formats Each data frame is between 4 and 16 bits long, depending on the size of data programmed, and is transmitted starting with the MSB. There are three basic frame types that can be selected: ■ Texas Instruments synchronous serial ■ Freescale SPI ■ MICROWIRE For all three formats, the serial clock (SSIClk) is held inactive while the SSI is idle, and SSIClk transitions at the programmed frequency only during active transmission or reception of data. The idle state of SSIClk is utilized to provide a receive timeout indication that occurs when the receive FIFO still contains data after a timeout period. For Freescale SPI and MICROWIRE frame formats, the serial frame (SSIFss ) pin is active Low, and is asserted (pulled down) during the entire transmission of the frame. For Texas Instruments synchronous serial frame format, the SSIFss pin is pulsed for one serial clock period starting at its rising edge, prior to the transmission of each frame. For this frame format, both the SSI and the off-chip slave device drive their output data on the rising edge of SSIClk, and latch data from the other device on the falling edge. Unlike the full-duplex transmission of the other two frame formats, the MICROWIRE format uses a special master-slave messaging technique, which operates at half-duplex. In this mode, when a frame begins, an 8-bit control message is transmitted to the off-chip slave. During this transmit, no incoming data is received by the SSI. After the message has been sent, the off-chip slave decodes it and, after waiting one serial clock after the last bit of the 8-bit control message has been sent, responds with the requested data. The returned data can be 4 to 16 bits in length, making the total frame length anywhere from 13 to 25 bits. 14.2.4.1 Texas Instruments Synchronous Serial Frame Format Figure 14-2 on page 328 shows the Texas Instruments synchronous serial frame format for a single transmitted frame. June 14, 2007 327 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Figure 14-2. TI Synchronous Serial Frame Format (Single Transfer) SSIClk SSIFss MSB SSITx/SSIRx LSB 4 to 16 bits In this mode, SSIClk and SSIFss are forced Low, and the transmit data line SSITx is tristated whenever the SSI is idle. Once the bottom entry of the transmit FIFO contains data, SSIFss is pulsed High for one SSIClk period. The value to be transmitted is also transferred from the transmit FIFO to the serial shift register of the transmit logic. On the next rising edge of SSIClk, the MSB of the 4 to 16-bit data frame is shifted out on the SSITx pin. Likewise, the MSB of the received data is shifted onto the SSIRx pin by the off-chip serial slave device. Both the SSI and the off-chip serial slave device then clock each data bit into their serial shifter on the falling edge of each SSIClk. The received data is transferred from the serial shifter to the receive FIFO on the first rising edge of SSIClk after the LSB has been latched. Figure 14-3 on page 328 shows the Texas Instruments synchronous serial frame format when back-to-back frames are transmitted. Figure 14-3. TI Synchronous Serial Frame Format (Continuous Transfer) SSIClk SSIFss MSB SSITx/SSIRx LSB 4 to 16 bits 14.2.4.2 Freescale SPI Frame Format The Freescale SPI interface is a four-wire interface where the SSIFss signal behaves as a slave select. The main feature of the Freescale SPI format is that the inactive state and phase of the SSIClk signal are programmable through the SPO and SPH bits within the SSISCR0 control register. SPO Clock Polarity Bit When the SPO clock polarity control bit is Low, it produces a steady state Low value on the SSIClk pin. If the SPO bit is High, a steady state High value is placed on the SSIClk pin when data is not being transferred. SPH Phase Control Bit The SPH phase control bit selects the clock edge that captures data and allows it to change state. It has the most impact on the first bit transmitted by either allowing or not allowing a clock transition before the first data capture edge. When the SPH phase control bit is Low, data is captured on the first clock edge transition. If the SPH bit is High, data is captured on the second clock edge transition. 328 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 14.2.4.3 Freescale SPI Frame Format with SPO=0 and SPH=0 Single and continuous transmission signal sequences for Freescale SPI format with SPO=0 and SPH=0 are shown in Figure 14-4 on page 329 and Figure 14-5 on page 329. Figure 14-4. Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0 SSIClk SSIFss SSIRx MSB LSB Q 4 to 16 bits MSB SSITx LSB Figure 14-5. Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0 SSIClk SSIFss SSIRx LSB MSB LSB MSB 4 to 16 bits SSITx LSB Note: MSB LSB MSB Q is undefined. In this configuration, during idle periods: ■ SSIClk is forced Low ■ SSIFss is forced High ■ The transmit data line SSITx is arbitrarily forced Low ■ When the SSI is configured as a master, it enables the SSIClk pad ■ When the SSI is configured as a slave, it disables the SSIClk pad If the SSI is enabled and there is valid data within the transmit FIFO, the start of transmission is signified by the SSIFss master signal being driven Low. This causes slave data to be enabled onto the SSIRx input line of the master. The master SSITx output pad is enabled. One half SSIClk period later, valid master data is transferred to the SSITx pin. Now that both the master and slave data have been set, the SSIClk master clock pin goes High after one further half SSIClk period. The data is now captured on the rising and propagated on the falling edges of the SSIClk signal. In the case of a single word transmission, after all bits of the data word have been transferred, the SSIFss line is returned to its idle High state one SSIClk period after the last bit has been captured. However, in the case of continuous back-to-back transmissions, the SSIFss signal must be pulsed High between each data word transfer. This is because the slave select pin freezes the data in its June 14, 2007 329 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) serial peripheral register and does not allow it to be altered if the SPH bit is logic zero. Therefore, the master device must raise the SSIFss pin of the slave device between each data transfer to enable the serial peripheral data write. On completion of the continuous transfer, the SSIFss pin is returned to its idle state one SSIClk period after the last bit has been captured. 14.2.4.4 Freescale SPI Frame Format with SPO=0 and SPH=1 The transfer signal sequence for Freescale SPI format with SPO=0 and SPH=1 is shown in Figure 14-6 on page 330, which covers both single and continuous transfers. Figure 14-6. Freescale SPI Frame Format with SPO=0 and SPH=1 SSIClk SSIFss SSIRx Q LSB MSB Q 4 to 16 bits SSITx Note: MSB LSB Q is undefined. In this configuration, during idle periods: ■ SSIClk is forced Low ■ SSIFss is forced High ■ The transmit data line SSITx is arbitrarily forced Low ■ When the SSI is configured as a master, it enables the SSIClk pad ■ When the SSI is configured as a slave, it disables the SSIClk pad If the SSI is enabled and there is valid data within the transmit FIFO, the start of transmission is signified by the SSIFss master signal being driven Low. The master SSITx output is enabled. After a further one half SSIClk period, both master and slave valid data is enabled onto their respective transmission lines. At the same time, the SSIClk is enabled with a rising edge transition. Data is then captured on the falling edges and propagated on the rising edges of the SSIClk signal. In the case of a single word transfer, after all bits have been transferred, the SSIFss line is returned to its idle High state one SSIClk period after the last bit has been captured. For continuous back-to-back transfers, the SSIFss pin is held Low between successive data words and termination is the same as that of the single word transfer. 14.2.4.5 Freescale SPI Frame Format with SPO=1 and SPH=0 Single and continuous transmission signal sequences for Freescale SPI format with SPO=1 and SPH=0 are shown in Figure 14-7 on page 331 and Figure 14-8 on page 331. 330 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 14-7. Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0 SSIClk SSIFss SSIRx MSB LSB Q 4 to 16 bits SSITx MSB Note: Q is undefined. LSB Figure 14-8. Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0 SSIClk SSIFss MSB SSITx/SSIRxLSB LSB MSB 4 to 16 bits In this configuration, during idle periods: ■ SSIClk is forced High ■ SSIFss is forced High ■ The transmit data line SSITx is arbitrarily forced Low ■ When the SSI is configured as a master, it enables the SSIClk pad ■ When the SSI is configured as a slave, it disables the SSIClk pad If the SSI is enabled and there is valid data within the transmit FIFO, the start of transmission is signified by the SSIFss master signal being driven Low, which causes slave data to be immediately transferred onto the SSIRx line of the master. The master SSITx output pad is enabled. One half period later, valid master data is transferred to the SSITx line. Now that both the master and slave data have been set, the SSIClk master clock pin becomes Low after one further half SSIClk period. This means that data is captured on the falling edges and propagated on the rising edges of the SSIClk signal. In the case of a single word transmission, after all bits of the data word are transferred, the SSIFss line is returned to its idle High state one SSIClk period after the last bit has been captured. However, in the case of continuous back-to-back transmissions, the SSIFss signal must be pulsed High between each data word transfer. This is because the slave select pin freezes the data in its serial peripheral register and does not allow it to be altered if the SPH bit is logic zero. Therefore, the master device must raise the SSIFss pin of the slave device between each data transfer to enable the serial peripheral data write. On completion of the continuous transfer, the SSIFss pin is returned to its idle state one SSIClk period after the last bit has been captured. June 14, 2007 331 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) 14.2.4.6 Freescale SPI Frame Format with SPO=1 and SPH=1 The transfer signal sequence for Freescale SPI format with SPO=1 and SPH=1 is shown in Figure 14-9 on page 332, which covers both single and continuous transfers. Figure 14-9. Freescale SPI Frame Format with SPO=1 and SPH=1 SSIClk SSIFss SSIRx Q LSB MSB Q 4 to 16 bits SSITx MSB Note: Q is undefined. LSB In this configuration, during idle periods: ■ SSIClk is forced High ■ SSIFss is forced High ■ The transmit data line SSITx is arbitrarily forced Low ■ When the SSI is configured as a master, it enables the SSIClk pad ■ When the SSI is configured as a slave, it disables the SSIClk pad If the SSI is enabled and there is valid data within the transmit FIFO, the start of transmission is signified by the SSIFss master signal being driven Low. The master SSITx output pad is enabled. After a further one-half SSIClk period, both master and slave data are enabled onto their respective transmission lines. At the same time, SSIClk is enabled with a falling edge transition. Data is then captured on the rising edges and propagated on the falling edges of the SSIClk signal. After all bits have been transferred, in the case of a single word transmission, the SSIFss line is returned to its idle high state one SSIClk period after the last bit has been captured. For continuous back-to-back transmissions, the SSIFss pin remains in its active Low state, until the final bit of the last word has been captured, and then returns to its idle state as described above. For continuous back-to-back transfers, the SSIFss pin is held Low between successive data words and termination is the same as that of the single word transfer. 14.2.4.7 MICROWIRE Frame Format Figure 14-10 on page 333 shows the MICROWIRE frame format, again for a single frame. Figure 14-11 on page 334 shows the same format when back-to-back frames are transmitted. 332 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 14-10. MICROWIRE Frame Format (Single Frame) SSIClk SSIFss SSITx MSB LSB 8-bit control SSIRx 0 MSB LSB 4 to 16 bits output data MICROWIRE format is very similar to SPI format, except that transmission is half-duplex instead of full-duplex, using a master-slave message passing technique. Each serial transmission begins with an 8-bit control word that is transmitted from the SSI to the off-chip slave device. During this transmission, no incoming data is received by the SSI. After the message has been sent, the off-chip slave decodes it and, after waiting one serial clock after the last bit of the 8-bit control message has been sent, responds with the required data. The returned data is 4 to 16 bits in length, making the total frame length anywhere from 13 to 25 bits. In this configuration, during idle periods: ■ SSIClk is forced Low ■ SSIFss is forced High ■ The transmit data line SSITx is arbitrarily forced Low A transmission is triggered by writing a control byte to the transmit FIFO. The falling edge of SSIFss causes the value contained in the bottom entry of the transmit FIFO to be transferred to the serial shift register of the transmit logic, and the MSB of the 8-bit control frame to be shifted out onto the SSITx pin. SSIFss remains Low for the duration of the frame transmission. The SSIRx pin remains tristated during this transmission. The off-chip serial slave device latches each control bit into its serial shifter on the rising edge of each SSIClk. After the last bit is latched by the slave device, the control byte is decoded during a one clock wait-state, and the slave responds by transmitting data back to the SSI. Each bit is driven onto the SSIRx line on the falling edge of SSIClk. The SSI in turn latches each bit on the rising edge of SSIClk. At the end of the frame, for single transfers, the SSIFss signal is pulled High one clock period after the last bit has been latched in the receive serial shifter, which causes the data to be transferred to the receive FIFO. Note: The off-chip slave device can tristate the receive line either on the falling edge of SSIClk after the LSB has been latched by the receive shifter, or when the SSIFss pin goes High. For continuous transfers, data transmission begins and ends in the same manner as a single transfer. However, the SSIFss line is continuously asserted (held Low) and transmission of data occurs back-to-back. The control byte of the next frame follows directly after the LSB of the received data from the current frame. Each of the received values is transferred from the receive shifter on the falling edge of SSIClk, after the LSB of the frame has been latched into the SSI. June 14, 2007 333 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Figure 14-11. MICROWIRE Frame Format (Continuous Transfer) SSIClk SSIFss SSITx LSB MSB LSB 8-bit control SSIRx 0 MSB LSB MSB 4 to 16 bits output data In the MICROWIRE mode, the SSI slave samples the first bit of receive data on the rising edge of SSIClk after SSIFss has gone Low. Masters that drive a free-running SSIClk must ensure that the SSIFss signal has sufficient setup and hold margins with respect to the rising edge of SSIClk. Figure 14-12 on page 334 illustrates these setup and hold time requirements. With respect to the SSIClk rising edge on which the first bit of receive data is to be sampled by the SSI slave, SSIFss must have a setup of at least two times the period of SSIClk on which the SSI operates. With respect to the SSIClk rising edge previous to this edge, SSIFss must have a hold of at least one SSIClk period. Figure 14-12. MICROWIRE Frame Format, SSIFss Input Setup and Hold Requirements tSetup=(2*tSSIClk) tHold=tSSIClk SSIClk SSIFss SSIRx First RX data to be sampled by SSI slave 14.3 Initialization and Configuration To use the SSI, its peripheral clock must be enabled by setting the SSI bit in the RCGC1 register. For each of the frame formats, the SSI is configured using the following steps: 1. Ensure that the SSE bit in the SSICR1 register is disabled before making any configuration changes. 2. Select whether the SSI is a master or slave: a. For master operations, set the SSICR1 register to 0x00000000. b. For slave mode (output enabled), set the SSICR1 register to 0x00000004. c. For slave mode (output disabled), set the SSICR1 register to 0x0000000C. 3. Configure the clock prescale divisor by writing the SSICPSR register. 334 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 4. Write the SSICR0 register with the following configuration: ■ Serial clock rate (SCR) ■ Desired clock phase/polarity, if using Freescale SPI mode (SPH and SPO) ■ The protocol mode: Freescale SPI, TI SSF, MICROWIRE (FRF) ■ The data size (DSS) 5. Enable the SSI by setting the SSE bit in the SSICR1 register. As an example, assume the SSI must be configured to operate with the following parameters: ■ Master operation ■ Freescale SPI mode (SPO=1, SPH=1) ■ 1 Mbps bit rate ■ 8 data bits Assuming the system clock is 20 MHz, the bit rate calculation would be: FSSIClk = FSysClk / (CPSDVSR * (1 + SCR)) 1x106 = 20x106 / (CPSDVSR * (1 + SCR)) In this case, if CPSDVSR=2, SCR must be 9. The configuration sequence would be as follows: 1. Ensure that the SSE bit in the SSICR1 register is disabled. 2. Write the SSICR1 register with a value of 0x00000000. 3. Write the SSICPSR register with a value of 0x00000002. 4. Write the SSICR0 register with a value of 0x000009C7. 5. The SSI is then enabled by setting the SSE bit in the SSICR1 register to 1. 14.4 Register Map Table 14-1 on page 335 lists the SSI registers. The offset listed is a hexadecimal increment to the register’s address, relative to that SSI module’s base address: ■ SSI0: 0x4000.8000 Note: The SSI must be disabled (see the SSE bit in the SSICR1 register) before any of the control registers are reprogrammed. Table 14-1. SSI Register Map Offset Name Type Reset Description See page 0x000 SSICR0 R/W 0x0000.0000 SSI Control 0 337 June 14, 2007 335 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Offset Name Type Reset Description See page 0x004 SSICR1 R/W 0x0000.0000 SSI Control 1 339 0x008 SSIDR R/W 0x0000.0000 SSI Data 340 0x00C SSISR RO 0x0000.0003 SSI Status 341 0x010 SSICPSR R/W 0x0000.0000 SSI Clock Prescale 342 0x014 SSIIM R/W 0x0000.0000 SSI Interrupt Mask 343 0x018 SSIRIS RO 0x0000.0008 SSI Raw Interrupt Status 344 0x01C SSIMIS RO 0x0000.0000 SSI Masked Interrupt Status 345 0x020 SSIICR W1C 0x0000.0000 SSI Interrupt Clear 346 0xFD0 SSIPeriphID4 RO 0x0000.0000 SSI Peripheral Identification 4 347 0xFD4 SSIPeriphID5 RO 0x0000.0000 SSI Peripheral Identification 5 348 0xFD8 SSIPeriphID6 RO 0x0000.0000 SSI Peripheral Identification 6 349 0xFDC SSIPeriphID7 RO 0x0000.0000 SSI Peripheral Identification 7 350 0xFE0 SSIPeriphID0 RO 0x0000.0022 SSI Peripheral Identification 0 351 0xFE4 SSIPeriphID1 RO 0x0000.0000 SSI Peripheral Identification 1 352 0xFE8 SSIPeriphID2 RO 0x0000.0018 SSI Peripheral Identification 2 353 0xFEC SSIPeriphID3 RO 0x0000.0001 SSI Peripheral Identification 3 354 0xFF0 SSIPCellID0 RO 0x0000.000D SSI PrimeCell Identification 0 355 0xFF4 SSIPCellID1 RO 0x0000.00F0 SSI PrimeCell Identification 1 356 0xFF8 SSIPCellID2 RO 0x0000.0005 SSI PrimeCell Identification 2 357 0xFFC SSIPCellID3 RO 0x0000.00B1 SSI PrimeCell Identification 3 358 14.5 Register Descriptions The remainder of this section lists and describes the SSI registers, in numerical order by address offset. 336 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 1: SSI Control 0 (SSICR0), offset 0x000 SSICR0 is control register 0 and contains bit fields that control various functions within the SSI module. Functionality such as protocol mode, clock rate and data size are configured in this register. SSI Control 0 (SSICR0) SSI0 base: 0x4000.8000 Offset 0x000 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 SPH SPO R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset SCR Type Reset FRF R/W 0 DSS Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:8 SCR R/W 0 SSI Serial Clock Rate The value SCR is used to generate the transmit and receive bit rate of the SSI. The bit rate is: BR=FSSIClk/(CPSDVSR * (1 + SCR)) where CPSDVSR is an even value from 2-254 programmed in the SSICPSR register, and SCR is a value from 0-255. 7 SPH R/W 0 SSI Serial Clock Phase This bit is only applicable to the Freescale SPI Format. The SPH control bit selects the clock edge that captures data and allows it to change state. It has the most impact on the first bit transmitted by either allowing or not allowing a clock transition before the first data capture edge. When the SPH bit is 0, data is captured on the first clock edge transition. If SPH is 1, data is captured on the second clock edge transition. 6 SPO R/W 0 SSI Serial Clock Polarity This bit is only applicable to the Freescale SPI Format. When the SPO bit is 0, it produces a steady state Low value on the SSIClk pin. If SPO is 1, a steady state High value is placed on the SSIClk pin when data is not being transferred. June 14, 2007 337 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Bit/Field Name Type Reset 5:4 FRF R/W 0 Description SSI Frame Format Select The FRF values are defined as follows: FRF Value Frame Format 3:0 DSS R/W 0 00 Freescale SPI Frame Format 01 Texas Intruments Synchronous Serial Frame Format 10 MICROWIRE Frame Format 11 Reserved SSI Data Size Select The DSS values are defined as follows: DSS Value Data Size 0000-0010 Reserved 0011 4-bit data 0100 5-bit data 0101 6-bit data 0110 7-bit data 0111 8-bit data 1000 9-bit data 1001 10-bit data 1010 11-bit data 1011 12-bit data 1100 13-bit data 1101 14-bit data 1110 15-bit data 1111 16-bit data 338 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: SSI Control 1 (SSICR1), offset 0x004 SSICR1 is control register 1 and contains bit fields that control various functions within the SSI module. Master and slave mode functionality is controlled by this register. SSI Control 1 (SSICR1) SSI0 base: 0x4000.8000 Offset 0x004 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 SOD MS SSE LBM RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 SOD R/W 0 SSI Slave Mode Output Disable This bit is relevant only in the Slave mode (MS=1). In multiple-slave systems, it is possible for the SSI master to broadcast a message to all slaves in the system while ensuring that only one slave drives data onto the serial output line. In such systems, the TXD lines from multiple slaves could be tied together. To operate in such a system, the SOD bit can be configured so that the SSI slave does not drive the SSITx pin. 0: SSI can drive SSITx output in Slave Output mode. 1: SSI must not drive the SSITx output in Slave mode. 2 MS R/W 0 SSI Master/Slave Select This bit selects Master or Slave mode and can be modified only when SSI is disabled (SSE=0). 0: Device configured as a master. 1: Device configured as a slave. 1 SSE R/W 0 SSI Synchronous Serial Port Enable Setting this bit enables SSI operation. 0: SSI operation disabled. 1: SSI operation enabled. Note: 0 LBM R/W 0 This bit must be set to 0 before any control registers are reprogrammed. SSI Loopback Mode Setting this bit enables Loopback Test mode. 0: Normal serial port operation enabled. 1: Output of the transmit serial shift register is connected internally to the input of the receive serial shift register. June 14, 2007 339 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 3: SSI Data (SSIDR), offset 0x008 SSIDR is the data register and is 16-bits wide. When SSIDR is read, the entry in the receive FIFO (pointed to by the current FIFO read pointer) is accessed. As data values are removed by the SSI receive logic from the incoming data frame, they are placed into the entry in the receive FIFO (pointed to by the current FIFO write pointer). When SSIDR is written to, the entry in the transmit FIFO (pointed to by the write pointer) is written to. Data values are removed from the transmit FIFO one value at a time by the transmit logic. It is loaded into the transmit serial shifter, then serially shifted out onto the SSITx pin at the programmed bit rate. When a data size of less than 16 bits is selected, the user must right-justify data written to the transmit FIFO. The transmit logic ignores the unused bits. Received data less than 16 bits is automatically right-justified in the receive buffer. When the SSI is programmed for MICROWIRE frame format, the default size for transmit data is eight bits (the most significant byte is ignored). The receive data size is controlled by the programmer. The transmit FIFO and the receive FIFO are not cleared even when the SSE bit in the SSICR1 register is set to zero. This allows the software to fill the transmit FIFO before enabling the SSI. SSI Data (SSIDR) SSI0 base: 0x4000.8000 Offset 0x008 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 DATA Type Reset R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 DATA R/W 0 SSI Receive/Transmit Data A read operation reads the receive FIFO. A write operation writes the transmit FIFO. Software must right-justify data when the SSI is programmed for a data size that is less than 16 bits. Unused bits at the top are ignored by the transmit logic. The receive logic automatically right-justifies the data. 340 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 4: SSI Status (SSISR), offset 0x00C SSISR is a status register that contains bits that indicate the FIFO fill status and the SSI busy status. SSI Status (SSISR) SSI0 base: 0x4000.8000 Offset 0x00C Type RO, reset 0x0000.0003 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 BSY RFF RNE TNF TFE RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 R0 1 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset Description 31:5 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 BSY RO 0 SSI Busy Bit 0: SSI is idle. 1: SSI is currently transmitting and/or receiving a frame, or the transmit FIFO is not empty. 3 RFF RO 0 SSI Receive FIFO Full 0: Receive FIFO is not full. 1: Receive FIFO is full. 2 RNE RO 0 SSI Receive FIFO Not Empty 0: Receive FIFO is empty. 1: Receive FIFO is not empty. 1 TNF RO 1 SSI Transmit FIFO Not Full 0: Transmit FIFO is full. 1: Transmit FIFO is not full. 0 TFE R0 1 SSI Transmit FIFO Empty 0: Transmit FIFO is not empty. 1: Transmit FIFO is empty. June 14, 2007 341 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 5: SSI Clock Prescale (SSICPSR), offset 0x010 SSICPSR is the clock prescale register and specifies the division factor by which the system clock must be internally divided before further use. The value programmed into this register must be an even number between 2 and 254. The least-significant bit of the programmed number is hard-coded to zero. If an odd number is written to this register, data read back from this register has the least-significant bit as zero. SSI Clock Prescale (SSICPSR) SSI0 base: 0x4000.8000 Offset 0x010 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 CPSDVSR RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 CPSDVSR R/W 0 SSI Clock Prescale Divisor This value must be an even number from 2 to 254, depending on the frequency of SSIClk. The LSB always returns 0 on reads. 342 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: SSI Interrupt Mask (SSIIM), offset 0x014 The SSIIM register is the interrupt mask set or clear register. It is a read/write register and all bits are cleared to 0 on reset. On a read, this register gives the current value of the mask on the relevant interrupt. A write of 1 to the particular bit sets the mask, enabling the interrupt to be read. A write of 0 clears the corresponding mask. SSI Interrupt Mask (SSIIM) SSI0 base: 0x4000.8000 Offset 0x014 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 1 0 TXIM RXIM RTIM RORIM R/W 0 R/W 0 R/W 0 R/W 0 RO 0 Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TXIM R/W 0 SSI Transmit FIFO Interrupt Mask 0: TX FIFO half-full or less condition interrupt is masked. 1: TX FIFO half-full or less condition interrupt is not masked. 2 RXIM R/W 0 SSI Receive FIFO Interrupt Mask 0: RX FIFO half-full or more condition interrupt is masked. 1: RX FIFO half-full or more condition interrupt is not masked. 1 RTIM R/W 0 SSI Receive Time-Out Interrupt Mask 0: RX FIFO time-out interrupt is masked. 1: RX FIFO time-out interrupt is not masked. 0 RORIM R/W 0 SSI Receive Overrun Interrupt Mask 0: RX FIFO overrun interrupt is masked. 1: RX FIFO overrun interrupt is not masked. June 14, 2007 343 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 7: SSI Raw Interrupt Status (SSIRIS), offset 0x018 The SSIRIS register is the raw interrupt status register. On a read, this register gives the current raw status value of the corresponding interrupt prior to masking. A write has no effect. SSI Raw Interrupt Status (SSIRIS) SSI0 base: 0x4000.8000 Offset 0x018 Type RO, reset 0x0000.0008 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 TXRIS RXRIS RTRIS RORRIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TXRIS RO 1 SSI Transmit FIFO Raw Interrupt Status Indicates that the transmit FIFO is half full or less, when set. 2 RXRIS RO 0 SSI Receive FIFO Raw Interrupt Status Indicates that the receive FIFO is half full or more, when set. 1 RTRIS RO 0 SSI Receive Time-Out Raw Interrupt Status Indicates that the receive time-out has occurred, when set. 0 RORRIS RO 0 SSI Receive Overrun Raw Interrupt Status Indicates that the receive FIFO has overflowed, when set. 344 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 8: SSI Masked Interrupt Status (SSIMIS), offset 0x01C The SSIMIS register is the masked interrupt status register. On a read, this register gives the current masked status value of the corresponding interrupt. A write has no effect. SSI Masked Interrupt Status (SSIMIS) SSI0 base: 0x4000.8000 Offset 0x01C Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 TXMIS RXMIS RTMIS RORMIS RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 TXMIS RO 0 SSI Transmit FIFO Masked Interrupt Status Indicates that the transmit FIFO is half full or less, when set. 2 RXMIS RO 0 SSI Receive FIFO Masked Interrupt Status Indicates that the receive FIFO is half full or more, when set. 1 RTMIS RO 0 SSI Receive Time-Out Masked Interrupt Status Indicates that the receive time-out has occurred, when set. 0 RORMIS RO 0 SSI Receive Overrun Masked Interrupt Status Indicates that the receive FIFO has overflowed, when set. June 14, 2007 345 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 9: SSI Interrupt Clear (SSIICR), offset 0x020 The SSIICR register is the interrupt clear register. On a write of 1, the corresponding interrupt is cleared. A write of 0 has no effect. SSI Interrupt Clear (SSIICR) SSI0 base: 0x4000.8000 Offset 0x020 Type W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RTIC RORIC RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 W1C 0 W1C 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 RTIC W1C 0 SSI Receive Time-Out Interrupt Clear 0: No effect on interrupt. 1: Clears interrupt. 0 RORIC W1C 0 SSI Receive Overrun Interrupt Clear 0: No effect on interrupt. 1: Clears interrupt. 346 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 10: SSI Peripheral Identification 4 (SSIPeriphID4), offset 0xFD0 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 4 (SSIPeriphID4) SSI0 base: 0x4000.8000 Offset 0xFD0 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID4 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID4 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register[7:0] Can be used by software to identify the presence of this peripheral. June 14, 2007 347 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 11: SSI Peripheral Identification 5 (SSIPeriphID5), offset 0xFD4 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 5 (SSIPeriphID5) SSI0 base: 0x4000.8000 Offset 0xFD4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID5 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID5 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register[15:8] Can be used by software to identify the presence of this peripheral. 348 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 12: SSI Peripheral Identification 6 (SSIPeriphID6), offset 0xFD8 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 6 (SSIPeriphID6) SSI0 base: 0x4000.8000 Offset 0xFD8 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID6 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID6 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register[23:16] Can be used by software to identify the presence of this peripheral. June 14, 2007 349 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 13: SSI Peripheral Identification 7 (SSIPeriphID7), offset 0xFDC The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 7 (SSIPeriphID7) SSI0 base: 0x4000.8000 Offset 0xFDC Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID7 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID7 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register[31:24] Can be used by software to identify the presence of this peripheral. 350 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 14: SSI Peripheral Identification 0 (SSIPeriphID0), offset 0xFE0 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 0 (SSIPeriphID0) SSI0 base: 0x4000.8000 Offset 0xFE0 Type RO, reset 0x0000.0022 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 0 RO 0 RO 1 RO 0 reserved Type Reset reserved Type Reset PID0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID0 RO 0x22 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register[7:0] Can be used by software to identify the presence of this peripheral. June 14, 2007 351 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 15: SSI Peripheral Identification 1 (SSIPeriphID1), offset 0xFE4 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 1 (SSIPeriphID1) SSI0 base: 0x4000.8000 Offset 0xFE4 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID1 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID1 RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [15:8] Can be used by software to identify the presence of this peripheral. 352 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 16: SSI Peripheral Identification 2 (SSIPeriphID2), offset 0xFE8 The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 2 (SSIPeriphID2) SSI0 base: 0x4000.8000 Offset 0xFE8 Type RO, reset 0x0000.0018 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset PID2 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID2 RO 0x18 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [23:16] Can be used by software to identify the presence of this peripheral. June 14, 2007 353 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 17: SSI Peripheral Identification 3 (SSIPeriphID3), offset 0xFEC The SSIPeriphIDn registers are hard-coded and the fields within the register determine the reset value. SSI Peripheral Identification 3 (SSIPeriphID3) SSI0 base: 0x4000.8000 Offset 0xFEC Type RO, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 reserved Type Reset reserved Type Reset PID3 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 PID3 RO 0x01 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI Peripheral ID Register [31:24] Can be used by software to identify the presence of this peripheral. 354 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 18: SSI PrimeCell Identification 0 (SSIPCellID0), offset 0xFF0 The SSIPCellIDn registers are hard-coded and the fields within the register determine the reset value. SSI PrimeCell Identification 0 (SSIPCellID0) SSI0 base: 0x4000.8000 Offset 0xFF0 Type RO, reset 0x0000.000D 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 0 RO 1 reserved Type Reset reserved Type Reset CID0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID0 RO 0x0D Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI PrimeCell ID Register [7:0] Provides software a standard cross-peripheral identification system. June 14, 2007 355 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 19: SSI PrimeCell Identification 1 (SSIPCellID1), offset 0xFF4 The SSIPCellIDn registers are hard-coded and the fields within the register determine the reset value. SSI PrimeCell Identification 1 (SSIPCellID1) SSI0 base: 0x4000.8000 Offset 0xFF4 Type RO, reset 0x0000.00F0 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 1 RO 1 RO 1 RO 1 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset CID1 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID1 RO 0xF0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI PrimeCell ID Register [15:8] Provides software a standard cross-peripheral identification system. 356 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 20: SSI PrimeCell Identification 2 (SSIPCellID2), offset 0xFF8 The SSIPCellIDn registers are hard-coded and the fields within the register determine the reset value. SSI PrimeCell Identification 2 (SSIPCellID2) SSI0 base: 0x4000.8000 Offset 0xFF8 Type RO, reset 0x0000.0005 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 1 RO 0 RO 1 reserved Type Reset reserved Type Reset CID2 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID2 RO 0x05 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI PrimeCell ID Register [23:16] Provides software a standard cross-peripheral identification system. June 14, 2007 357 Luminary Micro Confidential-Advance Product Information Synchronous Serial Interface (SSI) Register 21: SSI PrimeCell Identification 3 (SSIPCellID3), offset 0xFFC The SSIPCellIDn registers are hard-coded and the fields within the register determine the reset value. SSI PrimeCell Identification 3 (SSIPCellID3) SSI0 base: 0x4000.8000 Offset 0xFFC Type RO, reset 0x0000.00B1 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 1 RO 0 RO 1 RO 1 RO 0 RO 0 RO 0 RO 1 reserved Type Reset reserved Type Reset CID3 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 CID3 RO 0xB1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. SSI PrimeCell ID Register [31:24] Provides software a standard cross-peripheral identification system. 358 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 15 2 Inter-Integrated Circuit (I C) Interface I2C 2 The Inter-Integrated Circuit (I C) bus provides bi-directional data transfer through a two-wire design 2 (a serial data line SDA and a serial clock line SCL), and interfaces to external I C devices such as 2 serial memory (RAMs and ROMs), networking devices, LCDs, tone generators, and so on. The I C bus may also be used for system testing and diagnostic purposes in product development and 2 manufacture. The LM3S8938 microcontroller includes two I C modules, providing the ability to 2 interact (both send and receive) with other I C devices on the bus. 2 ® 2 Devices on the I C bus can be designated as either a master or a slave. Each Stellaris I C module supports both sending and receiving data as either a master or a slave, and also supports the 2 simultaneous operation as both a master and a slave. There are a total of four I C modes: Master ® 2 Transmit, Master Receive, Slave Transmit, and Slave Receive. The Stellaris I C modules can operate at two speeds: Standard (100 Kbps) and Fast (400 Kbps). 2 2 Both the I C master and slave can generate interrupts; the I C master generates interrupts when 2 a transmit or receive operation completes (or aborts due to an error) and the I C slave generates interrupts when data has been sent or requested by a master. 15.1 Block Diagram 2 Figure 15-1. I C Block Diagram I2CSCL I2C Control Interrupt I2CMSA I2CSOAR I2CMCS I2CSCSR I2CMDR I2CSDR I2CMTPR I2CSIM I2CMIMR I2CSRIS I2CMRIS I2CSMIS I2CMMIS I2CSICR I2CSDA I2CSCL I2C I/O Select I2CSDA I2CSCL 2 I2CMICR I C Slave Core I2CSDA I2CMCR 15.2 I2C Master Core Functional Description 2 TheEach I C module is comprised of both master and slave functions which are implemented as separate peripherals. For proper operation, the SDA and SCL pins must be connected to bi-directional 2 open-drain pads. A typical I C bus configuration is shown in Figure 15-2 on page 360. 2 2 See “I C” on page 515 for I C timing diagrams. June 14, 2007 359 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Figure 15-2. I C Bus Configuration RPUP SCL SDA I2C Bus I2CSCL I2CSDA SCL SDA 3rd Party Device with I2C Interface StellarisTM 15.2.1 RPUP SCL SDA 3rd Party Device with I2C Interface 2 I C Bus Functional Overview 2 ® The I C bus uses only two signals: SDA and SCL, named I2CSDA and I2CSCL on Stellaris microcontrollers. SDA is the bi-directional serial data line and SCL is the bi-directional serial clock line. The bus is considered idle when both lines are high. 2 Every transaction on the I C bus is nine bits long, consisting of eight data bits and a single acknowledge bit. The number of bytes per transfer (defined as the time between a valid START and STOP condition, described in “START and STOP Conditions” on page 360) is unrestricted, but each byte has to be followed by an acknowledge bit, and data must be transferred MSB first. When a receiver cannot receive another complete byte, it can hold the clock line SCL Low and force the transmitter into a wait state. The data transfer continues when the receiver releases the clock SCL. 15.2.1.1 START and STOP Conditions 2 The protocol of the I C bus defines two states to begin and end a transaction: START and STOP. A high-to-low transition on the SDA line while the SCL is high is defined as a START condition, and a low-to-high transition on the SDA line while SCL is high is defined as a STOP condition. The bus is considered busy after a START condition and free after a STOP condition. See Figure 15-3 on page 360. Figure 15-3. START and STOP Conditions SDA SDA SCL SCL START condition STOP condition 15.2.1.2 Data Format with 7-Bit Address Data transfers follow the format shown in Figure 15-4 on page 361. After the START condition, a slave address is sent. This address is 7-bits long followed by an eighth bit, which is a data direction bit (R/S bit in the I2CMSA register). A zero indicates a transmit operation (send), and a one indicates a request for data (receive). A data transfer is always terminated by a STOP condition generated by the master, however, a master can initiate communications with another device on the bus by generating a repeated START condition and addressing another slave without first generating a STOP condition. Various combinations of receive/send formats are then possible within a single transfer. 360 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 15-4. Complete Data Transfer with a 7-Bit Address SDA MSB SCL 1 2 LSB R/S ACK 7 8 9 MSB 1 2 Slave address 7 LSB ACK 8 9 Data The first seven bits of the first byte make up the slave address (see Figure 15-5 on page 361). The eighth bit determines the direction of the message. A zero in the R/S position of the first byte means that the master will write (send) data to the selected slave, and a one in this position means that the master will receive data from the slave. Figure 15-5. R/S Bit in First Byte MSB LSB R/S Slave address 15.2.1.3 Data Validity The data on the SDA line must be stable during the high period of the clock, and the data line can only change when SCL is low (see Figure 15-6 on page 361). 2 Figure 15-6. Data Validity During Bit Transfer on the I C Bus SDA SCL Data line Change stable of data allowed 15.2.1.4 Acknowledge All bus transactions have a required acknowledge clock cycle that is generated by the master. During the acknowledge cycle, the transmitter (which can be the master or slave) releases the SDA line. To acknowledge the transaction, the receiver must pull down SDA during the acknowledge clock cycle. The data sent out by the receiver during the acknowledge cycle must comply with the data validity requirements described in “Data Validity” on page 361. When a slave receiver does not acknowledge the slave address, SDA must be left high by the slave so that the master can generate a STOP condition and abort the current transfer. If the master device is acting as a receiver during a transfer, it is responsible for acknowledging each transfer made by the slave. Since the master controls the number of bytes in the transfer, it signals the end of data to the slave transmitter by not generating an acknowledge on the last data byte. The slave transmitter must then release SDA to allow the master to generate the STOP or a repeated START condition. June 14, 2007 361 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 15.2.1.5 Arbitration A master may start a transfer only if the bus is idle. Its possible for two or more masters to generate a START condition within minimum hold time of the START condition. In these situations, an arbitration scheme takes place on the SDA line, while SCL is high. During arbitration, the first of the competing master devices to place a '1' (high) on SDA while another master transmits a '0' (low) will switch off its data output stage and retire until the bus is idle again. Arbitration can take place over several bits. Its first stage is a comparison of address bits, and if both masters are trying to address the same device, arbitration continues on to the comparison of data bits. 15.2.2 Available Speed Modes 2 The I C clock rate is determined by the parameters: CLK_PRD, TIMER_PRD, SCL_LP, and SCL_HP. where: CLK_PRD is the system clock period SCL_LP is the low phase of SCL (fixed at 6) SCL_HP is the high phase of SCL (fixed at 4) 2 TIMER_PRD is the programmed value in the I C Master Timer Period (I2CMTPR) register (see page 379). 2 The I C clock period is calculated as follows: SCL_PERIOD = 2*(1 + TIMER_PRD)*(SCL_LP + SCL_HP)*CLK_PRD For example: CLK_PRD = 50 ns TIMER_PRD = 2 SCL_LP=6 SCL_HP=4 yields a SCL frequency of: 1/T = 333 Khz Table 15-1 on page 362 gives examples of Timer period, system clock, and speed mode (Standard or Fast). 2 Table 15-1. Examples of I C Master Timer Period versus Speed Mode System Clock Timer Period Standard Mode Timer Period Fast Mode 4 Mhz 0x01 100 Kbps - - 6 Mhz 0x02 100 Kbps - - 12.5 Mhz 0x06 89 Kbps 0x01 312 Kbps 16.7 Mhz 0x08 93 Kbps 0x02 278 Kbps 20 Mhz 0x09 100 Kbps 0x02 333 Kbps 25 Mhz 0x0C 96.2 Kbps 0x03 312 Kbps 33Mhz 0x10 97.1 Kbps 0x04 330 Kbps 40Mhz 0x13 100 Kbps 0x04 400 Kbps 362 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller System Clock Timer Period Standard Mode Timer Period Fast Mode 50Mhz 15.2.3 0x18 100 Kbps 0x06 357 Kbps Interrupts 2 The I C can generate interrupts when the following conditions are observed: ■ Master transaction completed ■ Master transaction error ■ Slave transaction received ■ Slave transaction requested 2 2 There is a separate interrupt signal for the I C master and I C modules. While both modules can generate interrupts for multiple conditions, only a single interrupt signal is sent to the interrupt controller. 2 15.2.3.1 I C Master Interrupts 2 The I C master module generates an interrupt when a transaction completes (either transmit or 2 receive), or when an error occurs during a transaction. To enable the I C master interrupt, software 2 must write a '1' to the I C Master Interrupt Mask (I2CMIMR) register. When an interrupt condition 2 is met, software must check the ERROR bit in the I C Master Control/Status (I2CMCS) register to verify that an error didn't occur during the last transaction. An error condition is asserted if the last transaction wasn't acknowledge by the slave or if the master was forced to give up ownership of the bus due to a lost arbitration round with another master. If an error is not detected, the application 2 can proceed with the transfer. The interrupt is cleared by writing a '1' to the I C Master Interrupt Clear (I2CMICR) register. If the application doesn't require the use of interrupts, the raw interrupt status is always visible via 2 the I C Master Raw Interrupt Status (I2CMRIS) register. 2 15.2.3.2 I C Slave Interrupts 2 The slave module generates interrupts as it receives requests from an I C master. To enable the 2 2 I C slave interrupt, write a '1' to the I C Slave Interrupt Mask (I2CSIMR) register. Software 2 determines whether the module should write (transmit) or read (receive) data from the I C Slave 2 Data (I2CSDR) register, by checking the RREQ and TREQ bits of the I C Slave Control/Status (I2CSCSR) register. If the slave module is in receive mode and the first byte of a transfer is received, 2 the FBR bit is set along with the RREQ bit. The interrupt is cleared by writing a '1' to the I C Slave Interrupt Clear (I2CSICR) register. If the application doesn't require the use of interrupts, the raw interrupt status is always visible via 2 the I C Slave Raw Interrupt Status (I2CSRIS) register. 15.2.4 Loopback Operation 2 The I C modules can be placed into an internal loopback mode for diagnostic or debug work. This 2 is accomplished by setting the LPBK bit in the I C Master Configuration (I2CMCR) register. In loopback mode, the SDA and SCL signals from the master and slave modules are tied together. June 14, 2007 363 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 15.2.5 Command Sequence Flow Charts 2 This section details the steps required to perform the various I C transfer types in both master and slave mode. 2 15.2.5.1 I C Master Command Sequences 2 The figures that follow show the command sequences available for the I C master. Figure 15-7. Master Single SEND Idle Write Slave Address to I2CMSA Sequence may be omitted in a Single Master system Write data to I2CMDR Read I2CMCS NO BUSBSY bit=0? YES Write ---0-111 to I2CMCS Read I2CMCS NO BUSY bit=0? YES Error Service NO ERROR bit=0? YES Idle 364 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 15-8. Master Single RECEIVE Idle Write Slave Address to I2CMSA Sequence may be omitted in a Single Master system Read I2CMCS NO BUSBSY bit=0? YES Write ---00111 to I2CMCS Read I2CMCS NO BUSY bit=0? YES Error Service NO ERROR bit=0? YES Read data from I2CMDR Idle June 14, 2007 365 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface Figure 15-9. Master Burst SEND Idle Write Slave Address to I2CMSA Sequence may be omitted in a Single Master system Read I2CMCS Write data to I2CMDR BUSY bit=0? YES Read I2CMCS ERROR bit=0? NO NO NO BUSBSY bit=0? YES Write data to I2CMDR YES Write ---0-011 to I2CMCS NO ARBLST bit=1? YES Write ---0-001 to I2CMCS NO Index=n? YES Write ---0-100 to I2CMCS Error Service Write ---0-101 to I2CMCS Idle Read I2CMCS NO BUSY bit=0? YES Error Service NO ERROR bit=0? YES Idle 366 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 15-10. Master Burst RECEIVE Idle Sequence may be omitted in a Single Master system Write Slave Address to I2CMSA Read I2CMCS BUSY bit=0? Read I2CMCS NO YES NO BUSBSY bit=0? ERROR bit=0? NO YES Write ---01011 to I2CMCS NO Read data from I2CMDR ARBLST bit=1? YES Write ---01001 to I2CMCS NO Write ---0-100 to I2CMCS Index=m-1? Error Service YES Write ---00101 to I2CMCS Idle Read I2CMCS BUSY bit=0? NO YES NO ERROR bit=0? YES Error Service Read data from I2CMDR Idle June 14, 2007 367 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface Figure 15-11. Master Burst RECEIVE after Burst SEND Idle Master operates in Master Transmit mode STOP condition is not generated Write Slave Address to I2CMSA Write ---01011 to I2CMCS Master operates in Master Receive mode Repeated START condition is generated with changing data direction Idle 368 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 15-12. Master Burst SEND after Burst RECEIVE Idle Master operates in Master Receive mode STOP condition is not generated Write Slave Address to I2CMSA Write ---0-011 to I2CMCS Master operates in Master Transmit mode Repeated START condition is generated with changing data direction Idle 2 15.2.5.2 I C Slave Command Sequences 2 Figure 15-13 on page 370 presents the command sequence available for the I C slave. June 14, 2007 369 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface Figure 15-13. Slave Command Sequence Idle Write OWN Slave Address to I2CSOAR Write -------1 to I2CSCSR Read I2CSCSR NO TREQ bit=1? YES Write data to I2CSDR 15.3 NO RREQ bit=1? FBR is also valid YES Read data from I2CSDR Initialization and Configuration 2 The following example shows how to configure the I C module to send a single byte as a master. This assumes the system clock is 20 MHz. 2 1. Enable the I C clock by writing a value of 0x0000.1000 to the RCGC1 register in the System Control module. 2. Enable the clock to the appropriate GPIO module via the RCGC2 register in the System Control module. 3. In the GPIO module, enable the appropriate pins for their alternate function using the GPIOAFSEL register. Also, be sure to enable the same pins for Open Drain operation. 2 4. Initialize the I C Master by writing the I2CMCR register with a value of 0x0000.0020. 5. Set the desired SCL clock speed of 100 Kbps by writing the I2CMTPR register with the correct value. The value written to the I2CMTPR register represents the number of system clock periods in one SCL clock period. The TPR value is determined by the following equation: 370 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller TPR = (System Clock / (2 * (SCL_LP + SCL_HP) * SCL_CLK)) - 1; TPR = (20MHz / (2 * (6 + 4) * 100000)) - 1; TPR = 9 Write the I2CMTPR register with the value of 0x0000.0009. 6. Specify the slave address of the master and that the next operation will be a Send by writing the I2CMSA register with a value of 0x0000.0076. This sets the slave address to 0x3B. 7. Place data (byte) to be sent in the data register by writing the I2CMDR register with the desired data. 8. Initiate a single byte send of the data from Master to Slave by writing the I2CMCS register with a value of 0x0000.0007 (STOP, START, RUN). 9. Wait until the transmission completes by polling the I2CMCS register’s BUSBSY bit until it has been cleared. 15.4 2 I C Register Map 2 2 Table 15-2 on page 371 lists the I C registers. All addresses given are relative to the I C base addresses for the master and slave: 2 ■ I C Master 0: 0x4002.0000 2 ■ I C Slave 0: 0x4002.0800 2 ■ I C Master 1: 0x4002.1000 2 ■ I C Slave 1: 0x4001.1800 2 Table 15-2. Inter-Integrated Circuit (I C) Interface Register Map Offset Description See page Name Type Reset 0x000 I2CMSA R/W 0x0000.0000 I2C Master Slave Address 373 0x004 I2CMCS R/W 0x0000.0000 I2C Master Control/Status 374 0x008 I2CMDR R/W 0x0000.0000 I2C Master Data 378 0x00C I2CMTPR R/W 0x0000.0001 I2C Master Timer Period 379 0x010 I2CMIMR R/W 0x0000.0000 I2C Master Interrupt Mask 380 0x014 I2CMRIS RO 0x0000.0000 I2C Master Raw Interrupt Status 381 0x018 I2CMMIS RO 0x0000.0000 I2C Master Masked Interrupt Status 382 0x01C I2CMICR WO 0x0000.0000 I2C Master Interrupt Clear 383 0x020 I2CMCR R/W 0x0000.0000 I2C Master Configuration 384 I2CSOAR R/W 0x0000.0000 I2C Slave Own Address 386 2 I C Master 2 I C Slave 0x000 June 14, 2007 371 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface Offset Name 0x004 Reset I2CSCSR RO 0x0000.0000 I2C Slave Control/Status 387 0x008 I2CSDR R/W 0x0000.0000 I2C Slave Data 389 0x00C I2CSIMR R/W 0x0000.0000 I2C Slave Interrupt Mask 390 0x010 I2CSRIS RO 0x0000.0000 I2C Slave Raw Interrupt Status 391 0x014 I2CSMIS RO 0x0000.0000 I2C Slave Masked Interrupt Status 392 0x018 I2CSICR WO 0x0000.0000 I2C Slave Interrupt Clear 393 15.5 Description See page Type 2 Register Descriptions (I C Master) 2 The remainder of this section lists and describes the I C master registers, in numerical order by address offset. See also “Register Descriptions (I2C Slave)” on page 385. 372 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 Register 1: I C Master Slave Address (I2CMSA), offset 0x000 This register consists of eight bits: seven address bits (A6-A0), and a Receive/Send bit, which determines if the next operation is a Receive (High), or Send (Low). I2C Master Slave Address (I2CMSA) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x000 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset SA RO 0 R/S Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:1 SA R/W 0 I C Slave Address 2 This field specifies bits A6 through A0 of the slave address. 0 R/S R/W 0 Receive/Send The R/S bit specifies if the next operation is a Receive (High) or Send (Low). 0: Send 1: Receive June 14, 2007 373 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Register 2: I C Master Control/Status (I2CMCS), offset 0x004 This register accesses four control bits when written, and accesses seven status bits when read. 2 The status register consists of seven bits, which when read determine the state of the I C bus controller. The control register consists of four bits: the RUN, START, STOP, and ACK bits. The START bit causes the generation of the START, or REPEATED START condition. The STOP bit determines if the cycle stops at the end of the data cycle, or continues on to a burst. 2 To generate a single send cycle, the I C Master Slave Address (I2CMSA) register is written with the desired address, the R/S bit is set to 0, and the Control register is written with ACK=X (0 or 1), STOP=1, START=1, and RUN=1 to perform the operation and stop. When the operation is completed (or aborted due an error), the interrupt pin becomes active and the data may be read from the 2 I2CMDR register. When the I C module operates in Master receiver mode, the ACK bit must be set 2 normally to logic 1. This causes the I C bus controller to send an acknowledge automatically after 2 each byte. This bit must be reset when the I C bus controller requires no further data to be sent from the slave transmitter. Read-Only Status Register I2C Master Control/Status (I2CMCS) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x004 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 BUSBSY IDLE RO 0 RO 0 R 0 R 0 reserved Type Reset reserved Type Reset RO 0 ARBLST DATACK ADRACK ERROR R 0 R 0 R 0 BUSY R 0 R 0 Bit/Field Name Type Reset Description 31:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 BUSBSY R 0 This bit specifies the state of the I C bus. If set, the bus is busy; otherwise, the bus is idle. The bit changes based on the START and STOP conditions. 5 IDLE R 0 This bit specifies the I C controller state. If set, the controller is idle; otherwise the controller is not idle. 4 ARBLST R 0 This bit specifies the result of bus arbitration. If set, the controller lost arbitration; otherwise, the controller won arbitration. 3 DATACK R 0 This bit specifies the result of the last data operation. If set, the transmitted data was not acknowledged; otherwise, the data was acknowledged. 2 2 374 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset Description 2 ADRACK R 0 This bit specifies the result of the last address operation. If set, the transmitted address was not acknowledged; otherwise, the address was acknowledged. 1 ERROR R 0 This bit specifies the result of the last bus operation. If set, an error occurred on the last operation; otherwise, no error was detected. The error can be from the slave address not being acknowledged, the transmit data not being acknowledged, or because the controller lost arbitration. 0 BUSY R 0 This bit specifies the state of the controller. If set, the controller is busy; otherwise, the controller is idle. When the BUSY bit is set, the other status bits are not valid. Write-Only Control Register I2C Master Control/Status (I2CMCS) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x004 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 1 0 ACK STOP START RUN W 0 W 0 W 0 W 0 Bit/Field Name Type Reset Description 31:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 ACK W 0 When set, causes received data byte to be acknowledged automatically by the master. See field decoding in Table 15-3 on page 376. 2 STOP W 0 When set, causes the generation of the STOP condition. See field decoding in Table 15-3 on page 376. 1 START W 0 When set, causes the generation of a START or repeated START condition. See field decoding in Table 15-3 on page 376. 0 RUN W 0 When set, allows the master to send or receive data. See field decoding in Table 15-3 on page 376. June 14, 2007 375 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface Table 15-3. Write Field Decoding for I2CMCS[3:0] Field (Sheet 1 of 3) Current I2CMSA[0] State R/S Idle I2CMCS[3:0] ACK Description STOP START RUN 0 X a 0 1 1 0 X 1 1 1 START condition followed by a SEND and STOP condition (master remains in Idle state). 1 0 0 1 1 START condition followed by RECEIVE operation with negative ACK (master goes to the Master Receive state). 1 0 1 1 1 START condition followed by RECEIVE and STOP condition (master remains in Idle state). 1 1 0 1 1 START condition followed by RECEIVE (master goes to the Master Receive state). 1 1 1 1 1 Illegal. START condition followed by SEND (master goes to the Master Transmit state). All other combinations not listed are non-operations. NOP. Master Transmit X X 0 0 1 SEND operation (master remains in Master Transmit state). X X 1 0 0 STOP condition (master goes to Idle state). X X 1 0 1 SEND followed by STOP condition (master goes to Idle state). 0 X 0 1 1 Repeated START condition followed by a SEND (master remains in Master Transmit state). 0 X 1 1 1 Repeated START condition followed by SEND and STOP condition (master goes to Idle state). 1 0 0 1 1 Repeated START condition followed by a RECEIVE operation with a negative ACK (master goes to Master Receive state). 1 0 1 1 1 Repeated START condition followed by a SEND and STOP condition (master goes to Idle state). 1 1 0 1 1 Repeated START condition followed by RECEIVE (master goes to Master Receive state). 1 1 1 1 1 Illegal. All other combinations not listed are non-operations. NOP. 376 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Current I2CMSA[0] State R/S Master Receive I2CMCS[3:0] Description ACK STOP START RUN X 0 0 0 1 RECEIVE operation with negative ACK (master remains in Master Receive state). X X 1 0 0 STOP condition (master goes to Idle state). X 0 1 0 1 RECEIVE followed by STOP condition (master goes to Idle state). X 1 0 0 1 RECEIVE operation (master remains in Master Receive state). X 1 1 0 1 Illegal. 1 0 0 1 1 Repeated START condition followed by RECEIVE operation with a negative ACK (master remains in Master Receive state). 1 0 1 1 1 Repeated START condition followed by RECEIVE and STOP condition (master goes to Idle state). 1 1 0 1 1 Repeated START condition followed by RECEIVE (master remains in Master Receive state). 0 X 0 1 1 Repeated START condition followed by SEND (master goes to Master Transmit state). 0 X 1 1 1 Repeated START condition followed by SEND and STOP condition (master goes to Idle state). b All other combinations not listed are non-operations. NOP. a. An X in a table cell indicates the bit can be 0 or 1. b. In Master Receive mode, a STOP condition should be generated only after a Data Negative Acknowledge executed by the master or an Address Negative Acknowledge executed by the slave. June 14, 2007 377 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Register 3: I C Master Data (I2CMDR), offset 0x008 This register contains the data to be transmitted when in the Master Transmit state, and the data received when in the Master Receive state. I2C Master Data (I2CMDR) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x008 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset DATA RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 DATA R/W 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Data transferred during transaction. 378 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 Register 4: I C Master Timer Period (I2CMTPR), offset 0x00C This register specifies the period of the SCL clock. I2C Master Timer Period (I2CMTPR) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x00C Type R/W, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 1 reserved Type Reset reserved Type Reset TPR RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0 7:0 TPR R/W 0x1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. This field specifies the period of the SCL clock. SCL_PRD = 2*(1 + TPR)*(SCL_LP + SCL_HP)*CLK_PRD where: 2 SCL_PRD is the SCL line period (I C clock). TPR is the Timer Period register value (range of 1 to 255). SCL_LP is the SCL Low period (fixed at 6). SCL_HP is the SCL High period (fixed at 4). June 14, 2007 379 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Register 5: I C Master Interrupt Mask (I2CMIMR), offset 0x010 This register controls whether a raw interrupt is promoted to a controller interrupt. I2C Master Interrupt Mask (I2CMIMR) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x010 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 IM Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 IM R/W 0 This bit controls whether a raw interrupt is promoted to a controller interrupt. If set, the interrupt is not masked and the interrupt is promoted; otherwise, the interrupt is masked. 380 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 Register 6: I C Master Raw Interrupt Status (I2CMRIS), offset 0x014 This register specifies whether an interrupt is pending. I2C Master Raw Interrupt Status (I2CMRIS) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x014 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 RIS RO 0 Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 RIS RO 0 This bit specifies the raw interrupt state (prior to masking) of the I C master block. If set, an interrupt is pending; otherwise, an interrupt is not pending. June 14, 2007 2 381 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Register 7: I C Master Masked Interrupt Status (I2CMMIS), offset 0x018 This register specifies whether an interrupt was signaled. I2C Master Masked Interrupt Status (I2CMMIS) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x018 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 MIS RO 0 Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 MIS RO 0 This bit specifies the raw interrupt state (after masking) of the I C master block. If set, an interrupt was signaled; otherwise, an interrupt has not been generated since the bit was last cleared. 382 2 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 Register 8: I C Master Interrupt Clear (I2CMICR), offset 0x01C This register clears the raw interrupt. I2C Master Interrupt Clear (I2CMICR) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x01C Type WO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 WO 0 reserved Type Reset reserved Type Reset RO 0 IC Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 IC WO 0 Interrupt Clear This bit controls the clearing of the raw interrupt. A write of 1 clears the interrupt; otherwise, a write of 0 has no affect on the interrupt state. A read of this register returns no meaningful data. June 14, 2007 383 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Register 9: I C Master Configuration (I2CMCR), offset 0x020 This register configures the mode (Master or Slave) and sets the interface for test mode loopback. I2C Master Configuration (I2CMCR) I2C Master 0 base: 0x4002.0000 I2C Master 1 base: 0x4002.1000 Offset 0x020 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 SFE MFE RO 0 RO 0 RO 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 reserved RO 0 RO 0 LPBK RO 0 R/W 0 Bit/Field Name Type Reset Description 31:6 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5 SFE R/W 0 I C Slave Function Enable 2 This bit specifies whether the interface may operate in Slave mode. If set, Slave mode is enabled; otherwise, Slave mode is disabled. 4 MFE R/W 0 2 I C Master Function Enable This bit specifies whether the interface may operate in Master mode. If set, Master mode is enabled; otherwise, Master mode is disabled and the interface clock is disabled. 3:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 LPBK R/W 0 I C Loopback 2 This bit specifies whether the interface is operating normally or in Loopback mode. If set, the device is put in a test mode loopback configuration; otherwise, the device operates normally. 384 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 15.6 Register Descriptions (I2C Slave) 2 The remainder of this section lists and describes the I C slave registers, in numerical order by 2 address offset. See also “Register Descriptions (I C Master)” on page 372. June 14, 2007 385 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Register 10: I C Slave Own Address (I2CSOAR), offset 0x000 ® 2 2 This register consists of seven address bits that identify the Stellaris I C device on the I C bus. I2C Slave Own Address (I2CSOAR) I2C Slave 0 base: 0x4002.0800 I2C Slave 1 base: 0x4001.1800 Offset 0x000 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 OAR R/W 0 Bit/Field Name Type Reset Description 31:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6:0 OAR R/W 0 I C Slave Own Address 2 This field specifies bits A6 through A0 of the slave address. 386 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 Register 11: I C Slave Control/Status (I2CSCSR), offset 0x004 This register accesses one control bit when written, and three status bits when read. The read-only Status register consists of three bits: the FBR, RREQ, and TREQ bits. The First ® Byte Received (FBR) bit is set only after the Stellaris device detects its own slave address 2 and receives the first data byte from the I C master. The Receive Request (RREQ) bit indicates ® 2 2 that the Stellaris I C device has received a data byte from an I C master. Read one data byte from 2 the I C Slave Data (I2CSDR) register to clear the RREQ bit. The Transmit Request (TREQ) bit ® 2 indicates that the Stellaris I C device is addressed as a Slave Transmitter. Write one data byte 2 into the I C Slave Data (I2CSDR) register to clear the TREQ bit. The write-only Control register consists of one bit: the DA bit. The DA bit enables and disables the ® 2 Stellaris I C slave operation. Read-Only Status Register I2C Slave Control/Status (I2CSCSR) I2C Slave 0 base: 0x4002.0800 I2C Slave 1 base: 0x4001.1800 Offset 0x004 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 FBR TREQ RREQ RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 FBR RO 0 Indicates that the first byte following the slave’s own address is received. This bit is only valid when the RREQ bit is set, and is automatically cleared when data has been read from the I2CSDR register. Note: This bit is not used for slave transmit operations. 2 1 TREQ RO 0 This bit specifies the state of the I C slave with regards to outstanding 2 transmit requests. If set, the I C unit has been addressed as a slave transmitter and uses clock stretching to delay the master until data has been written to the I2CSDR register. Otherwise, there is no outstanding transmit request. 0 RREQ RO 0 Receive Request 2 This bit specifies the status of the I C slave with regards to outstanding 2 receive requests. If set, the I C unit has outstanding receive data from 2 the I C master and uses clock stretching to delay the master until the data has been read from the I2CSDR register. Otherwise, no receive data is outstanding. June 14, 2007 387 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface Write-Only Control Register I2C Slave Control/Status (I2CSCSR) I2C Slave 0 base: 0x4002.0800 I2C Slave 1 base: 0x4001.1800 Offset 0x004 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 WO 0 reserved Type Reset reserved Type Reset RO 0 DA Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 DA WO 0 Device Active 2 1=Enables the I C slave operation. 2 0=Disables the I C slave operation. 388 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 Register 12: I C Slave Data (I2CSDR), offset 0x008 This register contains the data to be transmitted when in the Slave Transmit state, and the data received when in the Slave Receive state. I2C Slave Data (I2CSDR) I2C Slave 0 base: 0x4002.0800 I2C Slave 1 base: 0x4001.1800 Offset 0x008 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset DATA RO 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 DATA R/W 0x0 This field contains the data for transfer during a slave receive or transmit operation. June 14, 2007 389 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Register 13: I C Slave Interrupt Mask (I2CSIMR), offset 0x00C This register controls whether a raw interrupt is promoted to a controller interrupt. I2C Slave Interrupt Mask (I2CSIMR) I2C Slave 0 base: 0x4002.0800 I2C Slave 1 base: 0x4001.1800 Offset 0x00C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 IM Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 IM R/W 0 This bit controls whether a raw interrupt is promoted to a controller interrupt. If set, the interrupt is not masked and the interrupt is promoted; otherwise, the interrupt is masked. 390 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 Register 14: I C Slave Raw Interrupt Status (I2CSRIS), offset 0x010 This register specifies whether an interrupt is pending. I2C Slave Raw Interrupt Status (I2CSRIS) I2C Slave 0 base: 0x4002.0800 I2C Slave 1 base: 0x4001.1800 Offset 0x010 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 RIS RO 0 Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 RIS RO 0 This bit specifies the raw interrupt state (prior to masking) of the I C slave block. If set, an interrupt is pending; otherwise, an interrupt is not pending. June 14, 2007 2 391 Luminary Micro Confidential-Advance Product Information 2 Inter-Integrated Circuit (I C) Interface 2 Register 15: I C Slave Masked Interrupt Status (I2CSMIS), offset 0x014 This register specifies whether an interrupt was signaled. I2C Slave Masked Interrupt Status (I2CSMIS) I2C Slave 0 base: 0x4002.0800 I2C Slave 1 base: 0x4001.1800 Offset 0x014 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 MIS RO 0 Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 MIS RO 0 This bit specifies the raw interrupt state (after masking) of the I C slave block. If set, an interrupt was signaled; otherwise, an interrupt has not been generated since the bit was last cleared. 392 2 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 2 Register 16: I C Slave Interrupt Clear (I2CSICR), offset 0x018 This register clears the raw interrupt. I2C Slave Interrupt Clear (I2CSICR) I2C Slave 0 base: 0x4002.0800 I2C Slave 1 base: 0x4001.1800 Offset 0x018 Type WO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 WO 0 reserved Type Reset reserved Type Reset RO 0 IC Bit/Field Name Type Reset Description 31:1 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 IC WO 0 This bit controls the clearing of the raw interrupt. A write of 1 clears the interrupt; otherwise a write of 0 has no affect on the interrupt state. A read of this register returns no meaningful data. June 14, 2007 393 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module 16 Controller Area Network (CAN) Module CAN 16.1 Controller Area Network Overview Controller Area Network (CAN) is a multicast shared serial bus standard for connecting electronic control units (ECUs). CAN was specifically designed to be robust in electromagnetically noisy environments and can utilize a differential balanced line like RS-485 or a more robust twisted-pair wire. Originally created for automotive purposes, it is also used in many embedded control applications (such as industrial and medical). Bit rates up to 1 Mbps are possible at network lengths below 40 meters. Decreased bit rates allow longer network distances (for example, 125 Kbps at 500 m). 16.2 Controller Area Network Features ® The Stellaris CAN module supports the following features: ■ ■ ■ ■ ■ ■ ■ ■ ■ CAN protocol version 2.0 part A/B. Bit rates up to 1 Mbps. 32 message objects. Each message object has its own identifier mask. Maskable interrupt. Disable Automatic Retransmission mode for Time Triggered CAN (TTCAN) applications. Programmable Loopback mode for self-test operation. Programmable FIFO mode. Gluelessly attach to an external CAN PHY through the CAN0Tx and CAN0Rx pins. 394 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 16.3 Controller Area Network Block Diagram Figure 16-1. CAN Module Block Diagram CAN Control CANCTL CANSTS CANBIT CANINT CANTST CANBRPE CANIF1CRQ CANIF1CMSK CANIF1MSK1 CANIF1MSK2 CANIF1ARB1 CANIF1ARB2 APB Pins APB Interface CAN TX/RX CANIF1MCTL CAN Core CANIF1DA1 CANIF1DA2 CANIF1DB1 CANIF1DB2 CANIF2CRQ CANIF2CMSK CANIF2MSK1 CANIF2MSK2 CANIF2ARB1 CANIF2ARB2 CANIF2MCTL CANIF2DA1 CANIF2DA2 CANIF2DB1 CANIF2DB2 Message RAM 32 Message Objects June 14, 2007 395 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module 16.4 Controller Area Network Functional Description The CAN module conforms to the CAN protocol version 2.0 (parts A and B). Message transfers that include data, remote, error, and overload frames with an 11-bit identifier (standard) or a 29-bit identifier (extended) are supported. Transfer rates can be programmed up to 1 Mbps. The CAN module consists of three major parts: ■ CAN protocol controller and message handler ■ Message memory ■ CAN register interface The protocol controller transfers and receives the serial data from the CAN bus and passes the data on to the message handler. The message handler then loads this information into the appropriate message object based on the current filtering and identifiers in the message object memory. The message handler is also responsible for generating interrupts based on events on the CAN bus. The message object memory is a set of 32 identical memory blocks that hold the current configuration, status, and actual data for each message object. These are accessed via the CAN message object register interface. The message memory is not directly accessable in the Stellaris memory map, so ® the Stellaris CAN controller provides an interface to communicate with the message memory. The CAN message object register interface provides two register sets for communicating with the message objects. Since there is no direct access to the message object memory, these two interfaces must be used to read or write to each message object. The two message object interfaces allow parallel access to the CAN controller message objects when multiple objects may have new information that needs to be processed. 16.4.1 Initialization The software initialization is started by setting the INIT bit in the CAN Control (CANCTL) register, with software or by a hardware reset, or by going bus-off, which occurs when the transmitter's error counter exceeds a count of 255. While INIT is set, all message transfers to and from the CAN bus are stopped and the status of the CAN transmit output is recessive (High). Entering the initialization state does not change the configuration of the CAN controller, the message objects or the error counters. However, some configuration registers are only accessible when in the initialization state. To initialize the CAN controller, set the CAN Bit Timing (CANBIT) register and configure each message object. If a message object is not needed, it is sufficient to set it as not valid by clearing the MsgVal bit in the CANIFnARB2 register. Otherwise, the whole message object has to be initialized, as the fields of the message object may not have valid information causing unexpected results. Access to the CAN Bit Timing (CANBIT) register and to the CAN Baud Rate Prescalar Extension (CANBRPE) register to configure the bit timing are enabled when both the INIT and CCE bits in the CANCTL register are set. To leave the initialization state, the INIT bit must be cleared. Afterwards, the internal Bit Stream Processor (BSP) synchronizes itself to the data transfer on the CAN bus by waiting for the occurrence of a sequence of 11 consecutive recessive bits (Bus Idle) before it takes part in bus activities and starts message transfers. The initialization of the message objects is independent of being in the initialization state and can be done on the fly, but message objects should all be configured to particular identifiers or set to not valid before the BSP starts the message transfer. To change the configuration of a message object during normal operation, set the MsgVal bit in the CANIFnARB2 register to 0 (not valid). When the configuration is completed, MsgVal is set to 1 again (valid). 396 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 16.4.2 Operation Once the CAN module is initialized and the INIT bit in the CANCTL register is reset to 0, the CAN module synchronizes itself to the CAN bus and starts the message transfer. As messages are received, they are stored in their appropriate message objects if they pass the message handler's filtering. The whole message (including all arbitration bits, data-length code, and eight data bytes) is stored in the message object. If the Identifier Mask (the Msk bits in the CANIFnMSKn registers) is used, the arbitration bits which are masked to "don't care" may be overwritten in the message object. The CPU may read or write each message any time via the CAN Interface Registers (CANIFnCRQ, CANIFnCMSK, CANIFnMSKn, CANIFnARBn, CANIFnMCTL, CANIFnDAn, and CANIFnDBn). The message handler guarantees data consistency in case of concurrent accesses. The transmission of message objects are under the control of the software that is managing the CAN hardware. These can be message objects used for one-time data transfers, or permanent message objects used to respond in a more periodic manner. Permanent message objects have all arbitration and control set up and only the data bytes are updated. To start the transmission, the TxRqst bit in the CANTXRQn register and the NewDat bit in the CANNWDAn register are set. If several transmit messages are assigned to the same message object (when the number of message objects is not sufficient), the whole message object has to be configured before the transmission of this message is requested. The transmission of any number of message objects may be requested at the same time; they are transmitted according to their internal priority, which is based on the message identifier for the message object. Messages may be updated or set to not valid any time, even when their requested transmission is still pending. The old data is discarded when a message is updated before its pending transmission has started. Depending on the configuration of the message object, the transmission of a message may be requested autonomously by the reception of a remote frame with a matching identifier. There are two sets of CAN Interface Registers (CANIF1x and CANIF2x) which are used to access the Message Objects in the Message RAM. The CAN controller coordinates transfers to and from the Message RAM to and from the registers. The function of the two sets are independent and identical and can be used to queue transactions. 16.4.3 Transmitting Message Objects If the internal transmit shift register of the CAN module is ready for loading, and if there is no data transfer between the CAN Interface Registers and message RAM, the valid message object with the highest priority and which has a pending transmission request is loaded into the transmit shift register by the message handler and the transmission is started. The message object's NewDat bit is reset and can be viewed in the CANNWDAn register. After a successful transmission, and if no new data was written to the message object since the start of the transmission, the TxRqst bit in the CANIFnCMSK register is reset. If the TxIE bit in the CANIFnMCTL register is set, the IntPnd bit in the CANIFnMCTL register is set after a successful transmission. If the CAN module has lost the arbitration or if an error occurred during the transmission, the message is re-transmitted as soon as the CAN bus is free again. If, meanwhile, the transmission of a message with higher priority has been requested, the messages are transmitted in the order of their priority. 16.4.4 Configuring a Transmit Message Object Table 16-1 on page 398 specifies the bit settings for a transmit message object. June 14, 2007 397 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Table 16-1. Transmit Message Object Bit Settings Register CANIFnARB2 CANIFnCMSK CANIFnMCTL CANIFnARB2 Bit MsgVal Arb Data Mask EoB Dir Value 1 appl appl appl 1 1 CANIFnMCTL NewDat MsgLst RxIE TxIE IntPnd RmtEn TxRqst 0 0 0 appl 0 appl 0 The Xtd and ID bit fields in the CANIFnARBn registers are set by an application. They define the identifier and type of the outgoing message. If an 11-bit Identifier (Standard Frame) is used, it is programmed to bits [28:18] of CANIFnARB1, as bits 17:0 of CANIFnARBn are not used by the CAN controller for 11-bit identifiers. If the TxIE bit is set, the IntPnd bit is set after a successful transmission of the message object. If the RmtEn bit is set, a matching received Remote Frame causes the TxRqst bit to be set and the Remote Frame is autonomously answered by a Data Frame with the data from the message object. The DLC bit in the CANIFnMCTL register is set by an application. TxRqst and RmtEn may not be set before the data is valid. The CAN mask registers (Msk bits in CANIFnMSKn, UMask bit in CANIFnMCTL register, and MXtd and MDir bits in CANIFnMSK2 register) may be used (UMask=1) to allow groups of Remote Frames with similar identifiers to set the TxRqst bit. The Dir bit should not be masked. 16.4.5 Updating a Transmit Message Object The CPU may update the data bytes of a Transmit Message Object any time via the CAN Interface Registers and neither the MsgVal nor the TxRqst bits have to be reset before the update. Even if only a part of the data bytes are to be updated, all four bytes of the corresponding CANIFnDAn or CANIFnDBn register have to be valid before the content of that register is transferred to the message object. Either the CPU has to write all four bytes into the CANIFnDAn or CANIFnDBn register or the message object is transferred to the CANIFnDAn or CANIFnDBn register before the CPU writes the new data bytes. In order to just update the data in a message object, the WR, NewDat, DataA, and DataB bits are written to the CAN IFn Command Mask (CANIFnMSKn) register, followed by writing the CAN IFn Data registers, and then the number of the message object is written to the CAN IFn Command Request (CANIFnCRQ) register, to update the data bytes and the TxRqst bit at the same time. To prevent the reset of TxRqst at the end of a transmission that may already be in progress while the data is updated, NewDat has to be set together with TxRqst. When NewDat is set together with TxRqst, NewDat is reset as soon as the new transmission has started. 16.4.6 Accepting Received Message Objects When the arbitration and control field (ID + Xtd + RmtEn + DLC) of an incoming message is completely shifted into the CAN module, the message handling capability of the module starts scanning the message RAM for a matching valid message object. To scan the message RAM for a matching message object, the Acceptance Filtering unit is loaded with the arbitration bits from the core. Then the arbitration and mask fields (including MsgVal, UMask, NewDat, and EoB) of message object 1 are loaded into the Acceptance Filtering unit and compared with the arbitration field from the shift register. This is repeated with each following message object until a matching message object is found or until the end of the message RAM is reached. If a match occurs, the scanning is stopped and the message handler proceeds depending on the type of frame received. 398 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 16.4.7 Receiving a Data Frame The message handler stores the message from the CAN module receive shift register into the respective message object in the message RAM. It stores the data bytes, all arbitration bits, and the Data Length Code into the corresponding message object. This is implemented to keep the data bytes connected with the identifier even if arbitration mask registers are used. The CANIFnMCTL.NewDat bit is set to indicate that new data has been received. The CPU should reset CANIFnMCTL.NewDat when it reads the message object to indicate to the controller that the message has been received and the buffer is free to receive more messages. If the CAN controller receives a message and the CANIFnMCTL.NewDat bit was already set, the MsgLst bit is set to indicate that the previous data was lost. If the CANIFnMCTL.RxIE bit is set, the CANIFnMCTL.IntPnd bit is set, causing the CANINT interrupt register to point to the message object that just received a message. The CANIFnMCTL.TxRqst bit of this message object is reset to prevent the transmission of a Remote Frame, while the requested Data Frame has just been received. 16.4.8 Receiving a Remote Frame When a Remote Frame is received, three different configurations of the matching message object have to be considered: ■ Dir = 1 (direction = transmit), RmtEn = 1, UMask = 1 or 0 At the reception of a matching Remote Frame, the TxRqst bit of this message object is set. The rest of the message object remains unchanged. ■ Dir = 1 (direction = transmit), RmtEn = 0, UMask = 0 At the reception of a matching Remote Frame, the TxRqst bit of this message object remains unchanged; the Remote Frame is ignored. This remote frame is disabled and will not automatically respond or indicate that the remote frame ever happened. ■ Dir = 1 (direction = transmit), RmtEn = 0, UMask = 1 At the reception of a matching Remote Frame, the TxRqst bit of this message object is reset. The arbitration and control field (ID + Xtd + RmtEn + DLC) from the shift register is stored into the message object in the message RAM and the NewDat bit of this message object is set. The data field of the message object remains unchanged; the Remote Frame is treated similar to a received Data Frame. This is useful for a remote data request from another CAN device for which ® the Stellaris controller does not have readily available data The software must fill the data and answer the frame manually. 16.4.9 Receive/Transmit Priority The receive/transmit priority for the message objects is controlled by the message number. Message object 1 has the highest priority, while message object 32 has the lowest priority. If more than one transmission request is pending, the message objects are transmitted in order based on the message object with the lowest message number. This should not be confused with the message identifier as that priority is enforced by the CAN bus. This means that if message object 1 and message object 2 both have valid messages that need to be transmitted, message object 1 will always be transmitted first regardless of the message identifier in the message object itself. 16.4.10 Configuring a Receive Message Object Table 16-2 on page 400 specifies the bit settings for a transmit message object. June 14, 2007 399 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Table 16-2. Receive Message Object Bit Settings Register CANIFnARB2 CANIFnCMSK CANIFnMCTL CANIFnARB2 Bit MsgVal Arb Data Mask EoB Dir Value 1 appl appl appl 1 0 CANIFnMCTL NewDat MsgLst RxIE TxIE IntPnd RmtEn TxRqst 0 0 appl 0 0 0 0 The CAN arbitration registers (ID[28:0] and Xtd bit) are set by an application. They define the identifier and type of accepted received messages. If an 11-bit Identifier (Standard Frame) is used, it is programmed to ID[28:18] and ID[17:0] are ignored by the CAN controller. When a Data Frame with an 11-bit Identifier is received, the ID[17:0] field is set to 0. If the RxIE bit is set, the IntPnd bit is set when a received Data Frame is accepted and stored in the message object. When the message handler stores a Data Frame in the message object, it stores the received Data Length Code and eight data bytes. If the Data Length Code is less than 8, the remaining bytes of the message object are overwritten by nonspecified values. The CAN mask registers (Msk bits in CANIFnMSKn, UMask bit in CANIFnMCTL register, and MXtd and MDir bits in CANIFnMSK2 register) may be used (UMask=1) to allow groups of Data Frames with similar identifiers to be accepted. The Dir bit should not be masked in typical applications. 16.4.11 Handling of Received Message Objects The CPU may read a received message any time via the CAN Interface registers because the data consistency is guaranteed by the message handler state machine. Typically, the CPU first writes 0x007F to the CAN IFn Command Mask (CANIFnCMSK) register and then writes the number of the message object to the CAN IFn Command Request (CANIFnCRQ) register. That combination transfers the whole received message from the message RAM into the Message Buffer registers (CANIFnMSKn, CANIFnARBn, and CANIFnMCTL). Additionally, the NewDat and IntPnd bits are cleared in the message RAM, acknowledging that the message has been read and clearing the pending interrupt being generated by this message object. If the message object uses masks for acceptance filtering, the arbitration bits show which of the matching messages has been received. The actual value of NewDat shows whether a new message has been received since the last time this message object was read. The actual value of MsgLst shows whether more than one message has been received since the last time this message object was read. MsgLst is not automatically reset. Using a Remote Frame, the CPU may request new data from another CAN node on the CAN bus. Setting the TxRqst bit of a receive object causes the transmission of a Remote Frame with the receive object's identifier. This Remote Frame triggers the other CAN node to start the transmission of the matching Data Frame. If the matching Data Frame is received before the Remote Frame could be transmitted, the TxRqst bit is automatically reset. This prevents the possible loss of data when the other device on the CAN bus has already transmitted the data, slightly earlier than expected. 16.4.12 Handling of Interrupts If several interrupts are pending, the CAN Interrupt (CANINT) register points to the pending interrupt with the highest priority, disregarding their chronological order. An interrupt remains pending until the CPU has cleared it. 400 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller The Status Interrupt has the highest priority. Among the message interrupts, the message object's interrupt priority decreases with increasing message number. A message interrupt is cleared by clearing the message object's IntPnd bit. The Status Interrupt is cleared by reading the CAN Status (CANSTS) register. The interrupt identifier IntId in the CANINT register indicates the cause of the interrupt. When no interrupt is pending, the register holds the value to 0. If the value of CANINT is different from 0, then there is an interrupt pending. If the IE bit is set in the CANCTL register, the interrupt line to the CPU is active. The interrupt line remains active until CANINT is 0, all interrupt sources have been cleared, (the cause of the interrupt is reset), or until IE is reset, which disables interrupts from the CAN controller. The value 0x8000 in the CANINT register indicates that an interrupt is pending because the CAN module has updated, but not necessarily changed the CANSTS register (Error Interrupt or Status Interrupt). This indicates that there is either a new Error Interrupt or a new Status Interrupt. A write access can clear the RxOK, TxOK, and LEC flags in the CANSTS register, however, only a read access to the CANSTS register will clear the source of the status interrupt. IntId points to the pending message interrupt with the highest interrupt priority. The SIE bit in the CANCTL register controls whether a change of the status register may cause an interrupt. The EIE bit in the CANCTL register controls whether any interrupt from the CAN controller actually generates an interrupt to the microcontroller's interrupt controller. The CANINT interrupt register is updated even when the IE bit is set to zero. There are two possibilities when handling the source of a message interrupt. The first is to read the IntId bit in the CANINT interrupt register to determine the highest priority interrupt that is pending, and the second is to read the CAN Message Interrupt Pending (CANMSGnINT) register to see all of the message objects that have pending interrupts. An interrupt service routine reading the message that is the source of the interrupt may read the message and reset the message object's IntPnd at the same time by setting the ClrIntPnd bit in the CAN IFn Command Mask (CANIFnCMSK) register. When the IntPnd bit is cleared, the CANINT register will contain the message number for the next message object with a pending interrupt. 16.4.13 Bit Timing Configuration Error Considerations Even if minor errors in the configuration of the CAN bit timing do not result in immediate failure, the performance of a CAN network can be reduced significantly. In many cases, the CAN bit synchronization amends a faulty configuration of the CAN bit timing to such a degree that only occasionally an error frame is generated. In the case of arbitration, however, when two or more CAN nodes simultaneously try to transmit a frame, a misplaced sample point may cause one of the transmitters to become error passive. The analysis of such sporadic errors requires a detailed knowledge of the CAN bit synchronization inside a CAN node and of the CAN nodes' interaction on the CAN bus. 16.4.14 Bit Time and Bit Rate The CAN system supports bit rates in the range of lower than 1 Kbps up to 1000 Kbps. Each member of the CAN network has its own clock generator. The timing parameter of the bit time can be configured individually for each CAN node, creating a common bit rate even though the CAN nodes' oscillator periods may be different. Because of small variations in frequency caused by changes in temperature or voltage and by deteriorating components, these oscillators are not absolutely stable. As long as the variations June 14, 2007 401 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module remain inside a specific oscillator's tolerance range, the CAN nodes are able to compensate for the different bit rates by periodically resynchronizing to the bit stream. According to the CAN specification, the bit time is divided into four segments (see Figure 16-2 on page 402): the Synchronization Segment, the Propagation Time Segment, the Phase Buffer Segment 1, and the Phase Buffer Segment 2. Each segment consists of a specific, programmable number of time quanta (see Table 16-3 on page 402). The length of the time quantum (tq), which is the basic time unit of the bit time, is defined by the CAN controller's system clock (fsys) and the Baud Rate Prescaler (BRP): tq = BRP / fsys The CAN module's system clock fsys is the frequency of its CAN module clock (CAN_CLK) input. The Synchronization Segment Sync_Seg is that part of the bit time where edges of the CAN bus level are expected to occur; the distance between an edge that occurs outside of Sync_Seg and the Sync_Seg is called the phase error of that edge. The Propagation Time Segment Prop_Seg is intended to compensate for the physical delay times within the CAN network. The Phase Buffer Segments Phase_Seg1 and Phase_Seg2 surround the Sample Point. The (Re-)Synchronization Jump Width (SJW) defines how far a resynchronization may move the Sample Point inside the limits defined by the Phase Buffer Segments to compensate for edge phase errors. A given bit rate may be met by different bit-time configurations, but for the proper function of the CAN network, the physical delay times and the oscillator's tolerance range have to be considered. Figure 16-2. CAN Bit Time a Table 16-3. CAN Protocol Ranges Parameter Range BRP [1 .. 32] Defines the length of the time quantum tq Remark Sync_Seg 1 tq Prop_Seg [1 .. 8] tq Compensates for the physical delay times Fixed length, synchronization of bus input to system clock Phase_Seg1 [1 .. 8] tq May be lengthened temporarily by synchronization Phase_Seg2 [1 .. 8] tq May be shortened temporarily by synchronization 402 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Parameter Range SJW [1 .. 4] tq May not be longer than either Phase Buffer Segment Remark a. This table describes the minimum programmable ranges reqired by the CAN protocol. The bit timing configuration is programmed in two register bytes in the CANBIT register. The sum of Prop_Seg and Phase_Seg1 (as TSEG1) is combined with Phase_Seg2 (as TSEG2) in one byte, and SJW and BRP are combined in the other byte. In these bit timing registers, the four components TSEG1, TSEG2, SJW, and BRP have to be programmed to a numerical value that is one less than its functional value; so instead of values in the range of [1..n], values in the range of [0..n-1] are programmed. That way, for example, SJW (functional range of [1..4]) is represented by only two bits. Therefore, the length of the bit time is (programmed values): [TSEG1 + TSEG2 + 3] tq or (functional values): [Sync_Seg + Prop_Seg + Phase_Seg1 + Phase_Seg2] tq The data in the bit timing registers are the configuration input of the CAN protocol controller. The Baud Rate Prescalar (configured by BRP) defines the length of the time quantum, the basic time unit of the bit time; the Bit Timing Logic (configured by TSEG1, TSEG2, and SJW) defines the number of time quanta in the bit time. The processing of the bit time, the calculation of the position of the Sample Point, and occasional synchronizations are controlled by the CAN controller and are evaluated once per time quantum. The CAN controller translates messages to and from frames. It generates and discards the enclosing fixed format bits, inserts and extracts stuff bits, calculates and checks the CRC code, performs the error management, and decides which type of synchronization is to be used. It is evaluated at the Sample Point and processes the sampled bus input bit. The time after the Sample Point that is needed to calculate the next bit to be sent (that is, the data bit, CRC bit, stuff bit, error flag, or idle) is called the Information Processing Time (IPT). The IPT is application-specific but may not be longer than 2 tq; the CAN's IPT is 0 tq. Its length is the lower limit of the programmed length of Phase_Seg2. In case of synchronization, Phase_Seg2 may be shortened to a value less than IPT, which does not affect bus timing. 16.4.15 Calculating the Bit Timing Parameters Usually, the calculation of the bit timing configuration starts with a desired bit rate or bit time. The resulting bit time (1/bit rate) must be an integer multiple of the system clock period. The bit time may consist of 4 to 25 time quanta. Several combinations may lead to the desired bit time, allowing iterations of the following steps. The first part of the bit time to be defined is the Prop_Seg. Its length depends on the delay times measured in the system. A maximum bus length as well as a maximum node delay has to be defined for expandable CAN bus systems. The resulting time for Prop_Seg is converted into time quanta (rounded up to the nearest integer multiple of tq). The Sync_Seg is 1 tq long (fixed), which leaves (bit time - Prop_Seg - 1) tq for the two Phase Buffer Segments. If the number of remaining tq is even, the Phase Buffer Segments have the same length, that is, Phase_Seg2 = Phase_Seg1, else Phase_Seg2 = Phase_Seg1 + 1. June 14, 2007 403 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module The minimum nominal length of Phase_Seg2 has to be regarded as well. Phase_Seg2 may not be shorter than the CAN controller's Information Processing Time, which is, depending on the actual implementation, in the range of [0..2] tq. The length of the Synchronization Jump Width is set to its maximum value, which is the minimum of 4 and Phase_Seg1. The oscillator tolerance range necessary for the resulting configuration is calculated by the formula given below: (1 -df) x fnom <= fosc <= (1+ df) x fnom where: ■ df = maximum tolerance of oscillator frequency ■ fosc = actual oscillator frequency ■ fnom = nominal oscillator frequency Maximum frequency tolerance must take into account the following formulas: df <= (Phase_Seg1,Phase_Seg2)min/ 2 x (13 x tbit - Phase_Seg2) dfmax = 2 x df x fnom where: ■ Phase_Seg1 and Phase_Seg2 are from Table 16-3 on page 402 ■ tbit = Bit Time ■ dfmax = maximum difference between two oscillators If more than one configuration is possible, that configuration allowing the highest oscillator tolerance range should be chosen. CAN nodes with different system clocks require different configurations to come to the same bit rate. The calculation of the propagation time in the CAN network, based on the nodes with the longest delay times, is done once for the whole network. The CAN system's oscillator tolerance range is limited by the node with the lowest tolerance range. The calculation may show that bus length or bit rate have to be decreased or that the oscillator frequencies' stability has to be increased in order to find a protocol-compliant configuration of the CAN bit timing. The resulting configuration is written into the CAN Bit Timing (CANBIT) register : (Phase_Seg2-1)&(Phase_Seg1+Prop_Seg-1)&(SynchronizationJumpWidth-1)&(Prescaler-1) 16.4.15.1 Example for Bit Timing at High Baud Rate In this example, the frequency of CAN_CLK is 10 MHz, BRP is 0, and the bit rate is 1 Mbps. tq 100 ns = tCAN_CLK delay of bus driver 50 ns delay of receiver circuit 30 ns delay of bus line (40m) 220 ns 404 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller tProp 600 ns = 6 × tq tSJW 100 ns = 1 × tq tTSeg1 700 ns = tProp + tSJW tTSeg2 200 ns = Information Processing Time + 1 × tq tSync-Seg 100 ns = 1 × tq bit time 1000 ns = tSync-Seg + tTSeg1 + tTSeg2 tolerance for CAN_CLK 0.39 % = min(PB1,PB2)/ 2 × (13 x bit time - PB2) = 0.1us/ 2 x (13x 1us - 2us) In the above example, the concatenated bit time parameters are (2-1)3&(7-1)4&(1-1)2&(1-1)6, and CANBIT is programmed to 0x1600. 16.4.15.2 Example for Bit Timing at Low Baud Rate In this example, the frequency of CAN_CLK is 2 MHz, BRP is 1, and the bit rate is 100 Kbps. tq 1 ms = 2 × tCAN_CLK delay of bus driver 200 ns delay of receiver circuit 80 ns delay of bus line (40m) 220 ns tProp 1 ms = 1 × tq tSJW 4 ms = 4 × tq tTSeg1 5 ms = tProp + tSJW tTSeg2 4 ms = Information Processing Time + 3 × tq tSync-Seg 1 ms = 1 × tq bit time 10 ms = tSync-Seg + tTSeg1 + tTSeg2 tolerance for CAN_CLK 1.58 % = min(PB1,PB2)/ 2 x (13 x bit time - PB2) = 4us/ 2 x (13 x 10us - 4us) In this example, the concatenated bit time parameters are (4-1)3&(5-1)4&(4-1)2&(2-1)6, and CANBIT is programmed to 0x34C1. 16.5 Controller Area Network Register Map Table 16-4 on page 405 lists the registers. All addresses given are relative to the CAN base address of: ■ CAN0: 0x4004.0000 All accesses are on word (32-bit) boundaries. Table 16-4. CAN Register Map Offset Name Type Reset Description See page 0x000 CANCTL R/W 0x0000.0001 CAN Control 408 0x004 CANSTS R/W 0x0000.0000 CAN Status 410 0x008 CANERR RO 0x0000.0000 CAN Error Counter 413 0x00C CANBIT R/W 0x0000.2301 CAN Bit Timing 414 0x010 CANINT RO 0x0000.0000 CAN Interrupt 416 June 14, 2007 405 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Description See page Offset Name Type Reset 0x014 CANTST R/W 0x0000.0000 CAN Test 417 0x018 CANBRPE R/W 0x0000.0000 CAN Baud Rate Prescalar Extension 419 0x020 CANIF1CRQ R/W 0x0000.0001 CAN IF1 Command Request 420 0x024 CANIF1CMSK R/W 0x0000.0000 CAN IF1 Command Mask 421 0x028 CANIF1MSK1 R/W 0x0000.FFFF CAN IF1 Mask 1 424 0x02C CANIF1MSK2 R/W 0x0000.FFFF CAN IF1 Mask 2 425 0x030 CANIF1ARB1 R/W 0x0000.0000 CAN IF1 Arbitration 1 426 0x034 CANIF1ARB2 R/W 0x0000.0000 CAN IF1 Arbitration 2 427 0x038 CANIF1MCTL R/W 0x0000.0000 CAN IF1 Message Control 428 0x03C CANIF1DA1 R/W 0x0000.0000 CAN IF1 Data A1 430 0x040 CANIF1DA2 R/W 0x0000.0000 CAN IF1 Data A2 431 0x044 CANIF1DB1 R/W 0x0000.0000 CAN IF1 Data B1 432 0x048 CANIF1DB2 R/W 0x0000.0000 CAN IF1 Data B2 433 0x080 CANIF2CRQ R/W 0x0000.0001 CAN IF2 Command Request 420 0x084 CANIF2CMSK R/W 0x0000.0000 CAN IF2 Command Mask 421 0x088 CANIF2MSK1 R/W 0x0000.FFFF CAN IF2 Mask 1 424 0x08C CANIF2MSK2 R/W 0x0000.FFFF CAN IF2 Mask 2 425 0x090 CANIF2ARB1 R/W 0x0000.0000 CAN IF2 Arbitration 1 426 0x094 CANIF2ARB2 R/W 0x0000.0000 CAN IF2 Arbitration 2 427 0x098 CANIF2MCTL R/W 0x0000.0000 CAN IF2 Message Control 428 0x09C CANIF2DA1 R/W 0x0000.0000 CAN IF2 Data A1 430 0x0A0 CANIF2DA2 R/W 0x0000.0000 CAN IF2 Data A2 431 0x0A4 CANIF2DB1 R/W 0x0000.0000 CAN IF2 Data B1 432 0x0A8 CANIF2DB2 R/W 0x0000.0000 CAN IF2 Data B2 433 0x100 CANTXRQ1 RO 0x0000.0000 CAN Transmission Request 1 434 0x104 CANTXRQ2 RO 0x0000.0000 CAN Transmission Request 2 434 0x120 CANNWDA1 RO 0x0000.0000 CAN New Data 1 435 0x124 CANNWDA2 RO 0x0000.0000 CAN New Data 2 435 0x140 CANMSG1INT RO 0x0000.0000 CAN Message 1 Interrupt Pending 436 0x144 CANMSG2INT RO 0x0000.0000 CAN Message 2 Interrupt Pending 436 0x160 CANMSG1VAL RO 0x0000.0000 CAN Message 1 Valid 437 0x164 CANMSG2VAL RO 0x0000.0000 CAN Message 2 Valid 437 406 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 16.6 Register Descriptions The remainder of this section lists and describes the CAN registers, in numerical order by address offset. There are two sets of Interface Registers which are used to access the Message Objects in the Message RAM: CANIF1x and CANIF2x. The function of the two sets are identical and are used to queue transactions. June 14, 2007 407 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 1: CAN Control (CANCTL), offset 0x000 This control register initializes the module and enables test mode and interrupts. The bus-off recovery sequence (see CAN Specification Rev. 2.0) cannot be shortened by setting or resetting Init. If the device goes bus-off, it sets Init, stopping all bus activities. Once Init has been cleared by the CPU, the device then waits for 129 occurrences of Bus Idle (129 * 11 consecutive High bits) before resuming normal operations. At the end of the bus-off recovery sequence, the Error Management Counters are reset. During the waiting time after Init is reset, each time a sequence of 11 High bits has been monitored, a Bit0Error code is written to the CANSTS status register, enabling the CPU to readily check whether the CAN bus is stuck at dominant or continuously disturbed and to monitor the proceeding of the bus-off recovery sequence. CAN Control (CANCTL) CAN0 base: 0x4004.0000 Offset 0x000 Type R/W, reset 0x0000.0001 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 Test CCE DAR reserved EIE SIE IE INIT RO 0 R/W 0 R/W 0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 1 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000 7 Test R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Test Mode Enable 0: Normal Operation 1: Test Mode 6 CCE R/W 0 Configuration Change Enable 0: Do not allow write access to the CANBIT register. 1: Allow write access to the CANBIT register if the Init bit is 1. 5 DAR R/W 0 Disable Automatic Retransmission 0: Auto retransmission of disturbed messages is enabled. 1: Auto retransmission is disabled. 4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3 EIE R/W 0 Error Interrupt Enable 0: Disabled. No Error Status interrupt is generated. 1: Enabled. A change in the Boff or EWarn bits in the CANSTS register generates an interrupt. 408 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 2 SIE R/W 0 Description Status Change Interrupt Enable 0: Disabled. No Status Change interrupt is generated. 1: Enabled. An interrupt is generated when a message has successfully been transmitted or received, or a CAN bus error has been detected. A change in the TxOk or RxOk bits in the CANSTS register generates an interrupt. 1 IE R/W 0 Module Interrupt Enable 0: Interrupt disabled. 1: Interrupt enabled. 0 INIT R/W 1 Initialization 0: Normal operation. 1: Initialization started. June 14, 2007 409 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 2: CAN Status (CANSTS), offset 0x004 The status register contains information for interrupt servicing such as Bus-Off, error count threshold, and error types. The LEC field holds the code that indicates the type of the last error to occur on the CAN bus. This field is cleared to 0 when a message has been transferred (reception or transmission) without error. The unused error code 7 may be written by the CPU to check for updates. An Error Interrupt is generated by the BOff and EWarn bits and a Status Change Interrupt is generated by the RxOk, TxOk, and LEC bits, assuming that the corresponding enable bits in the CAN Control (CANCTL) register are set. A change of the EPass bit or a write to the RxOk, TxOk, or LEC bits does not generate an interrupt. Reading the CAN Status (CANSTS) register clears the CAN Interrupt (CANINT) register, if it is pending. CAN Status (CANSTS) CAN0 base: 0x4004.0000 Offset 0x004 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 2 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000 7 BOff RO 0 RO 0 RO 0 7 6 5 4 3 BOff EWarn EPass RxOK TxOK RO 0 RO 0 RO 0 R/W 0 R/W 0 LEC R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Bus-Off Status 0: Module is not in bus-off state. 1: Module is in bus-off state. 6 EWarn RO 0 Warning Status 0: Both error counters are below the error warning limit of 96. 1: At least one of the error counters has reached the error warning limit of 96. 5 EPass RO 0 Error Passive 0: The CAN module is in the Error Active state, that is, the receive or transmit error count is less than or equal to 127. 1: The CAN module is in the Error Passive state, that is, the receive or transmit error count is greater than 127. 410 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 4 RxOK R/W 0 Description Received a Message Successfully 0: Since this bit was last reset to 0, no message has been successfully received. 1: Since this bit was last reset to 0, a message has been successfully received, independent of the result of the acceptance filtering. This bit is never reset by the CAN module. 3 TxOK R/W 0 Transmitted a Message Successfully 0: Since this bit was last reset to 0, no message has been successfully transmitted. 1: Since this bit was last reset to 0, a message has been successfully transmitted error-free and acknowledged by at least one other node. This bit is never reset by the CAN module. June 14, 2007 411 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Bit/Field Name Type Reset 2:0 LEC R/W 0x0 Description Last Error Code (type of the last error to occur on the CAN bus) Value Definition 000 No Error 001 Stuff Error More than 5 equal bits in a sequence have occurred in a part of a received message where this is not allowed. 010 Form Error A fixed format part of the received frame has the wrong format. 011 ACK Error The message transmitted was not acknowledged by another node. 100 Bit 1 Error When a message is transmitted, the CAN controller monitors the data lines to detect any conflicts. When the arbitration field is transmitted, data conflicts are a part of the arbitration protocol. When other frame fields are transmitted, data conflicts are considered errors. A Bit 1 Error indicates that the device wanted to send a High level (logical 1) but the monitored bus value was Low (logical 0). 101 Bit 0 Error A Bit 0 Error indicates that the device wanted to send a Low level (logical 0) but the monitored bus value was High (logical 1). During bus-off recovery, this status is set each time a sequence of 11 High bits has been monitored. This enables the CPU to monitor the proceeding of the bus-off recovery sequence without any disturbances to the bus. 110 CRC Error The CRC checksum was incorrect in the received message indicate that the calculated value received did not match the calculated CRC of the data. 111 Unused When the LEC bit shows this value, no CAN bus event was detected since the CPU wrote this value to LEC. 412 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 3: CAN Error Counter (CANERR), offset 0x008 This register contains the error counter values, which can be used to analyze the cause of an error. CAN Error Counter (CANERR) CAN0 base: 0x4004.0000 Offset 0x008 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RP Type Reset RO 0 REC RO 0 TEC Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 RP RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Received Error Passive 0: The Receive Error counter is below the Error Passive level (127 or less). 1: The Receive Error counter has reached the Error Passive level (128 or greater). 14:8 REC RO 0x0 Receive Error Counter State of the receiver error counter (0 to 127). 7:0 TEC RO 0x0 Transmit Error Counter State of the transmit error counter (0 to 255). June 14, 2007 413 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 4: CAN Bit Timing (CANBIT), offset 0x00C This register is used to program the bit width and bit quantum. Values are to be programmed to an 8-MHz reference clock. This register is write-enabled by the CCE and Init bits in the CANCTL register. With a CAN module clock (CAN_CLK) of 8 MHz, the register reset value of 0x230 configures the CAN for a bit rate of 500 Kbps. CAN Bit Timing (CANBIT) CAN0 base: 0x4004.0000 Offset 0x00C Type R/W, reset 0x0000.2301 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 1 reserved Type Reset RO 0 RO 0 15 14 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 13 12 11 10 TSeg2 R/W 0 R/W 1 RO 0 RO 0 RO 0 9 8 7 TSeg1 R/W 0 R/W 0 R/W 0 R/W 1 Bit/Field Name Type Reset 31:15 reserved RO 0x0000 14:12 TSeg2 R/W 0x2 SJW R/W 1 R/W 0 BRP R/W 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Time Segment after Sample Point 0x00-0x07: The actual interpretation by the hardware of this value is such that one more than the value programmed here is used. So, for example, a reset value of 0x2 defines that there is 3(2+1) bit time quanta defined for Phase_Seg2 (see Figure 16-2 on page 402). The bit time quanta is defined by BRP. 11:8 TSeg1 R/W 0x3 Time Segment Before Sample Point 0x00-0x0F: The actual interpretation by the hardware of this value is such that one more than the value programmed here is used. So, for example, the reset value of 0x3 defines that there is 4(3+1) bit time quanta defined for Phase_Seg1 (see Figure 16-2 on page 402). The bit time quanta is define by BRP. 7:6 SJW R/W 0x0 (Re)Synchronization Jump Width 0x00-0x03: The actual interpretation by the hardware of this value is such that one more than the value programmed here is used. During the start of frame (SOF), if the CAN controller detects a phase error (misalignment), it can adjust the length of TSeg2 or TSeg1 by the value in SJW. So the reset value of 0 adjusts the length by 1 bit time quanta. 414 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 5:0 BRP R/W 0x1 Description Baud Rate Prescalar 0x00-0x03F: The value by which the oscillator frequency is divided for generating the bit time quanta. The bit time is built up from a multiple of this quantum. The actual interpretation by the hardware of this value is such that one more than the value programmed here is used. BRP defines the number of CAN clock periods that make up 1 bit time quanta, so the reset value is 2 bit time quanta (1+1). The BRPRE register can be used to further divide the bit time. June 14, 2007 415 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 5: CAN Interrupt (CANINT), offset 0x010 This register indicates the source of the interrupt. If several interrupts are pending, the CAN Interrupt (CANINT) register points to the pending interrupt with the highest priority, disregarding their chronological order. An interrupt remains pending until the CPU has cleared it. If the IntId bit is not 0x0000 (the default) and the IE bit in the CANCTL register is set, the interrupt is active. The interrupt line remains active until the IntId bit is set back to 0x0000 when the cause of all interrupts are reset or until IE is reset. CAN Interrupt (CANINT) CAN0 base: 0x4004.0000 Offset 0x010 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 IntId Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0000 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 IntId RO 0x0000 Interrupt Identifier The number in this field indicates the source of the interrupt. Value Definition 0x0000 No interrupt pending 0x0001-0x0020 Number of the message object that caused the interrupt 0x0021-0x7FFF Unused 0x8000 Status Interrupt 0x8001-0xFFFF Unused 416 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: CAN Test (CANTST), offset 0x014 This is the test mode register for self-test and external pin access. It is write-enabled by the Test bit in the CANCTL register. Different test functions may be combined but when the TX bit is not equal to 0x0, it disturbs message transmits. CAN Test (CANTST) CAN0 base: 0x4004.0000 Offset 0x014 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 LBack Silent Basic RO 0 RO 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset Rx RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000 7 Rx RO 0 Tx R/W 0 R/W 0 reserved RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Receive Observation Displays the value on the CANnRx pin. 6:5 Tx R/W 0x0 Transmit Control Overrides control of CANnTx pin. Value Description 4 LBack R/W 0 00 CAN_TX is controlled by the CAN module (default) 01 Sample Point signal driven on the CAN_TX pin 10 CAN_TX drives a Low value 11 CAN_TX drives a High value Loopback Mode 0: Disabled. 1: Enabled. 3 Silent R/W 0 Silent Mode Do not transmit data; monitor the bus. Also known as Bus Monitor mode. 0: Disabled. 1: Enabled. 2 Basic R/W 0 Basic Mode 0: Disabled. 1: Use CANIF1 registers as transmit buffer, and use CANIF2 registers as receive buffer. June 14, 2007 417 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Bit/Field Name Type Reset 1:0 reserved RO 0x0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 418 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 7: CAN Baud Rate Prescalar Extension (CANBRPE), offset 0x018 This register is used to further divide the bit time set with the BRP bit in the CANBIT register. It is write-enabled with the CCE bit in the CANCTL register. CAN Baud Rate Prescalar Extension (CANBRPE) CAN0 base: 0x4004.0000 Offset 0x018 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:4 reserved RO 0x0000 3:0 BRPE R/W 0x0 BRPE Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Baud Rate Prescalar Extension. 0x00-0x0F: Extend the BRP bit to values up to 1023. The actual interpretation by the hardware is one more than the value programmed by BRPE (MSBs) and BRP (LSBs) are used. June 14, 2007 419 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 8: CAN IF1 Command Request (CANIF1CRQ), offset 0x020 Register 9: CAN IF2 Command Request (CANIF2CRQ), offset 0x080 This register is used to start a transfer when its MNUM bit field is updated. Its Busy bit indicates that the information is transferring from the CAN Interface Registers to the internal message RAM. A message transfer is started as soon as there is a write of the message object number with the MNUM bit. With this write operation, the Busy bit is automatically set to 1 to indicate that a transfer is in progress. After a wait time of 3 to 6 CAN_CLK periods, the transfer between the interface register and the message RAM completes, which then sets the Busy bit back to 0. CAN IF1 Command Request (CANIF1CRQ) CAN0 base: 0x4004.0000 Offset 0x020 Type R/W, reset 0x0000.0001 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 2 1 0 R/W 0 R/W 0 R/W 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 Busy Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 4 3 reserved RO 0 RO 0 RO 0 RO 0 RO 0 MNUM RO 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 Busy RO 0x0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Busy Flag 0: Reset when read/write action has finished. 1: Set when a write occurs to the message number in this register. 14:6 reserved RO 0x00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5:0 MNUM R/W 0x01 Message Number Selects one of the 32 message objects in the message RAM for data transfer. The message objects are numbered from 1 to 32. Value Description 0x00 0 is not a valid message number; it is interpreted as 0x20, or object 32. 0x01-0x20 Indicates specified message object 1 to 32. 0x21-0x3F Not a valid message number; values are shifted and it is interpreted as 0x01-0x1F. 420 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 10: CAN IF1 Command Mask (CANIF1CMSK), offset 0x024 Register 11: CAN IF2 Command Mask (CANIF2CMSK), offset 0x084 The Command Mask registers specify the transfer direction and select which buffer registers are the source or target of the data transfer. CAN IF1 Command Mask (CANIF1CMSK) CAN0 base: 0x4004.0000 Offset 0x024 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 WRNRD Mask Arb Control DataA DataB R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset 31:8 reserved RO 0x0000 7 WRNRD R/W 0 ClrIntPnd TxRqst/NewDat R/W 0 R/W 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Write, Not Read 0: Read. Transfer the message object address specified by the CAN Command Request (CANIFnCRQ) register to the CAN message buffer registers (CANIFnMSK1, CANIFnMSK2, CANIFnARB1, CANIFnARB2, CANIFnCTL, CANIFnDA1, CANIFnDA2, CANIFnDB1, and CANIFnDB2). 1: Write. Transfer data from the message buffer registers to the message object address specified by the CANIFnCRQ register. 6 Mask R/W 0x0 Access Mask Bits When WRNRD=1 (writes): 0: Mask bits unchanged. 1: Transfer IDMask + Dir + MXtd to message object. When WRNRD=0 (reads): 0: Mask bits unchanged. 1: Transfer IDMask + Dir + MXtd of the message object into the Interface Registers. 5 Arb R/W 0x0 Access Arbitration Bits When WRNRD=1 (writes): 0: Arbitration bits unchanged. 1: Transfer ID + Dir + Xtd + MsgVal to message object. When WRNRD=0 (reads): 0: Arbitration bits unchanged. 1: Transfer ID + Dir + Xtd + MsgVal to Message Buffer Register. June 14, 2007 421 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Bit/Field Name Type Reset 4 Control R/W 0x0 Description Access Control Bits When WRNRD=1 (writes): 0: Control bits unchanged. 1: Transfer control bits to message object. When WRNRD=0 (reads): 0: Control bits unchanged. 1: Transfer control bits to Message Buffer Register. 3 ClrIntPnd R/W 0x0 Clear Interrupt Pending Bit Note: This bit is not used when in write (WRNRD=1). 0: IntPnd bit in CANIFnMCTL register remains unchanged. 1: Clear IntPnd bit in the CANIFnMCTL register in the message object. 2 TxRqst/NewDat R/W 0x0 When WRNRD=1 (writes): Access Transmission Request Bit 0: TxRqst bit unchanged. 1: Set TxRqst bit Note: If a transmission is requested by programming this TxRqst bit, the parallel TxRqst in the CANIFnMCTL register is ignored. When WRNRD=0 (reads): Access New Data Bit 0: NewDat bit unchanged. 1: Clear NewDat bit in the message object. Note: 1 DataA R/W 0x0 A read access to a message object can be combined with the reset of the control bits IntPdn and NewDat. The values of these bits that are transferred to the CANIFnMCTL register always reflect the status before resetting these bits. Access Data Byte 0 to 3 When WRNRD=1 (writes): 0: Data bytes 0-3 are unchanged. 1: Transfer data bytes 0-3 (CANIFnDA1 and CANIFnDA2) to message object. When WRNRD=0 (reads): 0: Data bytes 0-3 are unchanged. 1: Transfer data bytes 0-3 in message object to CANIFnDA1 and CANIFnDA2. 422 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 0 DataB R/W 0x0 Description Access Data Byte 4 to 7 When WRNRD=1 (writes): 0: Data bytes 4-7 unchanged. 1: Transfer data bytes 4-7 (CANIFnDB1 and CANIFnDB2) to message object. When WRNRD=0 (reads): 0: Data bytes 4-7 unchanged. 1: Transfer data bytes 4-7 in message object to CANIFnDB1 and CANIFnDB2. June 14, 2007 423 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 12: CAN IF1 Mask 1 (CANIF1MSK1), offset 0x028 Register 13: CAN IF2 Mask 1 (CANIF2MSK1), offset 0x088 The mask information provided in this register accompanies the data (CANIFnDAn), arbitration information (CANIFnARBn), and control information (CANIFnMCTL) to the message object in the message RAM. The mask is used with the ID bit in the CANIFnARBn register for acceptance filtering. Additional mask information is contained in the CANIFnMSK2 register. CAN IF1 Mask 1 (CANIF1MSK1) CAN0 base: 0x4004.0000 Offset 0x028 Type R/W, reset 0x0000.FFFF 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 reserved Type Reset Msk Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 Msk R/W 0xFF Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Identifier Mask 0: The corresponding identifier bit (ID) in the message object cannot inhibit the match in acceptance filtering. 1: The corresponding identifier bit (ID) is used for acceptance filtering. 424 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 14: CAN IF1 Mask 2 (CANIF1MSK2), offset 0x02C Register 15: CAN IF2 Mask 2 (CANIF2MSK2), offset 0x08C This register holds extended mask information that accompanies the CANIFnMSK1 register. CAN IF1 Mask 2 (CANIF1MSK2) CAN0 base: 0x4004.0000 Offset 0x02C Type R/W, reset 0x0000.FFFF 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 MXtd MDir reserved R/W 1 R/W 1 RO 1 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 R/W 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 reserved Type Reset Type Reset Msk Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 MXtd R/W 0x1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Mask Extended Identifier 0: The extended identifier bit (Xtd in the CANIFnARB2 register) has no effect on the acceptance filtering. 1: The extended identifier bit Xtd is used for acceptance filtering. 14 MDir R/W 0x1 Mask Message Direction 0: The message direction bit (Dir in the CANIFnARB2 register) has no effect for acceptance filtering. 1: The message direction bit Dir is used for acceptance filtering. 13 reserved RO 0x1 12:0 Msk R/W 0xFF Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Identifier Mask 0: The corresponding identifier bit (ID) in the message object cannot inhibit the match in acceptance filtering. 1: The corresponding identifier bit (ID) is used for acceptance filtering. June 14, 2007 425 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 16: CAN IF1 Arbitration 1 (CANIF1ARB1), offset 0x030 Register 17: CAN IF2 Arbitration 1 (CANIF2ARB1), offset 0x090 This register, along with CANIFnARB2, holds the identifiers for acceptance filtering. CAN IF1 Arbitration 1 (CANIF1ARB1) CAN0 base: 0x4004.0000 Offset 0x030 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset ID Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 ID R/W 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Message Identifier This bit field is used with the ID field in the CANIFnARB2 register to create the message identifier. ID[28:0] is the Extended Frame and ID[28:18] is the Standard Frame. 426 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 18: CAN IF1 Arbitration 2 (CANIF1ARB2), offset 0x034 Register 19: CAN IF2 Arbitration 2 (CANIF2ARB2), offset 0x094 This register, along with CANIFnARB1, holds information for acceptance filtering. CAN IF1 Arbitration 2 (CANIF1ARB2) CAN0 base: 0x4004.0000 Offset 0x034 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset MsgVal Xtd Dir R/W 0 R/W 0 R/W 0 Type Reset ID Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 MsgVal R/W 0x0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Message Valid 0: The message object is ignored by the message handler. 1: The message object is configured and will be considered by the message handler within the CAN controller. All unused message objects should have this bit cleared during initialization and before clearing the Init bit in the CANCTL register. The MsgVal bit must also be cleared before any of the following bits are modified or if the message object is no longer required: the ID bit fields in the CANIFnARBn registers, the Xtd and Dir bits in the CANIFnARB2 register, or the DLC bits in the CANIFnMCTL register. 14 Xtd R/W 0x0 Extended Identifier 0: The 11-bit Standard Identifier will be used for this message object. 1: The 29-bit Extended Identifier will be used for this message object. 13 Dir R/W 0x0 Message Direction 0: Receive. On TxRqst, a Remote Frame with the identifier of this message object is transmitted. On reception of a Data Frame with matching identifier, that message is stored in this message object. 1: Transmit. On TxRqst, the respective message object is transmitted as a Data Frame. On reception of a Remote Frame with matching identifier, TxRqst bit of this message object is set (if RmtEn=1). 12:0 ID R/W 0x0 Message Identifier Used with the ID bit in the CANIFnARB1 register to create the message identifier. ID[28:0] is the Extended Frame and ID[28:18] is the Standard Frame. June 14, 2007 427 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 20: CAN IF1 Message Control (CANIF1MCTL), offset 0x038 Register 21: CAN IF2 Message Control (CANIF2MCTL), offset 0x098 This register holds the control information associated with the message object to be sent to the Message RAM. CAN IF1 Message Control (CANIF1MCTL) CAN0 base: 0x4004.0000 Offset 0x038 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NewDat MsgLst IntPnd UMask TxIE RxIE RmtEn TxRqst EoB R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15 NewDat R/W 0x0 reserved RO 0 RO 0 DLC Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. New Data 0: No new data has been written into the data portion of this message object by the message handler since the last time this flag was cleared by the CPU. 1: The message handler or the CPU has written new data into the data portion of this message object. 14 MsgLst R/W 0x0 Message Lost 0 : No message was lost since the last time this bit was reset by the CPU. 1: The message handler stored a new message into this object when NewDat was set; the CPU has lost a message. This bit is only valid for message objects with the Dir bit in the CANIFnARB2 register set to 0 (receive). 13 IntPnd R/W 0x0 Interrupt Pending 0: This message object is not the source of an interrupt. 1: This message object is the source of an interrupt. The interrupt identifier in the CAN Interrupt (CANINT) register will point to this message object if there is not another interrupt source with a higher priority. 12 UMask R/W 0x0 Use Acceptance Mask 0: Mask ignored. 1: Use mask (Msk, MXtd, and MDir) for acceptance filtering. 428 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 11 TxIE R/W 0x0 Description Transmit Interrupt Enable 0: The IntPnd bit in the CANIFnMCTL register is unchanged after a successful transmission of a frame. 1: The IntPnd bit in the CANIFnMCTL register is set after a successful transmission of a frame. 10 RxIE R/W 0x0 Receive Interrupt Enable 0: The IntPnd bit in the CANIFnMCTL register is unchanged after a successful reception of a frame. 1: The IntPnd bit in the CANIFnMCTL register is set after a successful reception of a frame. 9 RmtEn R/W 0x0 Remote Enable 0: At the reception of a Remote Frame, the TxRqst bit in the CANIFnMCTL register is left unchanged. 1: At the reception of a Remote Frame, the TxRqst bit in the CANIFnMCTL register is set. 8 TxRqst R/W 0x0 Transmit Request 0: This message object is not waiting for transmission. 1: The transmission of this message object is requested and is not yet done. 7 EoB R/W 0x0 End of Buffer 0: Message object belongs to a FIFO Buffer and is not the last message object of that FIFO Buffer. 1: Single message object or last message object of a FIFO Buffer. This bit is used to concatenate two or more message objects (up to 32) to build a FIFO buffer. For a single message object (thus not belonging to a FIFO buffer), this bit must be set to 1. 6:4 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3:0 DLC R/W 0x0 Data Length Code Value Description 0x0-0x8 Specifies the number of bytes in the Data Frame. 0x9-0xF Defaults to a Data Frame with 8 bytes. The DLC bit in the CANIFnMCTL register of a message object must be defined the same as in all the corresponding objects with the same identifier at other nodes. When the message handler stores a data frame, it writes DLC to the value given by the received message. June 14, 2007 429 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 22: CAN IF1 Data A1 (CANIF1DA1), offset 0x03C Register 23: CAN IF2 Data A1 (CANIF2DA1), offset 0x09C This register (along with CANIFnDA2, CANIFnDB1, and CANIFnDB2) contains the data to be sent or that has been received. In a CAN Data Frame, data byte 0 is the first byte to be transmitted or received and data byte 7 is the last byte to be transmitted or received. In CAN's serial bit stream, the MSB of each byte is transmitted first. CAN IF1 Data A1 (CANIF1DA1) CAN0 base: 0x4004.0000 Offset 0x03C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset Data Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 Data R/W 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Data Bytes 1 and 0 430 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 24: CAN IF1 Data A2 (CANIF1DA2), offset 0x040 Register 25: CAN IF2 Data A2 (CANIF2DA2), offset 0x0A0 This register (along with CANIFnDA1, CANIFnDB1, and CANIFnDB2) contains the data to be sent or that has been received. In a CAN Data Frame, data byte 0 is the first byte to be transmitted or received and data byte 7 is the last byte to be transmitted or received. In CAN's serial bit stream, the MSB of each byte is transmitted first. CAN IF1 Data A2 (CANIF1DA2) CAN0 base: 0x4004.0000 Offset 0x040 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset Data Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 Data R/W 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Data Bytes 3 and 2 June 14, 2007 431 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 26: CAN IF1 Data B1 (CANIF1DB1), offset 0x044 Register 27: CAN IF2 Data B1 (CANIF2DB1), offset 0x0A4 This register (along with CANIFnDA1, CANIFnDA2, and CANIFnDB2) contains the data to be sent or that has been received. In a CAN Data Frame, data byte 0 is the first byte to be transmitted or received and data byte 7 is the last byte to be transmitted or received. In CAN's serial bit stream, the MSB of each byte is transmitted first. CAN IF1 Data B1 (CANIF1DB1) CAN0 base: 0x4004.0000 Offset 0x044 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset Data Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 Data R/W 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Data Bytes 5 and 4 432 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 28: CAN IF1 Data B2 (CANIF1DB2), offset 0x048 Register 29: CAN IF2 Data B2 (CANIF2DB2), offset 0x0A8 This register (along with CANIF1DA1, CANIF1DA2, and CANIF1DB1) contains the data to be sent or that has been received. In a CAN Data Frame, data byte 0 is the first byte to be transmitted or received and data byte 7 is the last byte to be transmitted or received. In CAN's serial bit stream, the MSB of each byte is transmitted first. CAN IF1 Data B2 (CANIF1DB2) CAN0 base: 0x4004.0000 Offset 0x048 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset Data Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 Data R/W 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Data Bytes 7 and 6 June 14, 2007 433 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 30: CAN Transmission Request 1 (CANTXRQ1), offset 0x100 Register 31: CAN Transmission Request 2 (CANTXRQ2), offset 0x104 The CANTXRQ1 and CANTXRQ2 registers hold the TxRqst bits of the 32 message objects. By reading out these bits, the CPU can check which message object has a transmission request pending. The TxRqst bit of a specific message object can be changed by three sources: (1) the CPU via the CAN IFn Message Control (CANIFnMCTL) register, (2) the message handler state machine after the reception of a Remote Frame, or (3) the message handler state machine after a successful transmission. The CANTXRQ1 register contains the TxRqst bit of the first 16 message objects in the message RAM; the CANTXRQ2 register contains the TxRqst bit of the second 16 message objects. CAN Transmission Request 1 (CANTXRQ1) CAN0 base: 0x4004.0000 Offset 0x100 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 TxRqst Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 TxRqst RO 0x00 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Transmission Request Bits (of all message objects) 0: The message object is not waiting for transmission. 1: The transmission of the message object is requested and is not yet done. 434 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 32: CAN New Data 1 (CANNWDA1), offset 0x120 Register 33: CAN New Data 2 (CANNWDA2), offset 0x124 The CANNWDA1 and CANNWDA2 registers hold the NewDat bits of the 32 message objects. By reading these bits, the CPU can check which message object has its data portion updated. The NewDat bit of a specific message object can be changed by three sources: (1) the CPU via the CAN IFn Message Control (CANIFnMCTL) register, (2) the message handler state machine after the reception of a Data Frame, or (3) the message handler state machine after a successful transmission. The CANNWDA1 register contains the NewDat bit of the first 16 message objects in the message RAM; the CANNWDA2 register contains the NewDat bit of the second 16 message objects. CAN New Data 1 (CANNWDA1) CAN0 base: 0x4004.0000 Offset 0x120 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 NewDat Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 NewDat RO 0x00 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. New Data Bits (of all message objects) 0: No new data has been written into the data portion of this message object by the message handler since the last time this flag was cleared by the CPU. 1: The message handler or the CPU has written new data into the data portion of this message object. June 14, 2007 435 Luminary Micro Confidential-Advance Product Information Controller Area Network (CAN) Module Register 34: CAN Message 1 Interrupt Pending (CANMSG1INT), offset 0x140 Register 35: CAN Message 2 Interrupt Pending (CANMSG2INT), offset 0x144 The CANMSG1INT and CANMSG2INT registers hold the IntPnd bits of the 32 message objects. By reading these bits, the CPU can check which message object has an interrupt pending. The IntPnd bit of a specific message object can be changed through two sources: (1) the CPU via the CAN IFn Message Control (CANIFnMCTL) register, or (2) the message handler state machine after the reception or transmission of a frame. This field is also encoded in the CAN Interrupt (CANINT) register. The CANMSG1INT register contains the IntPnd bit of the first 16 message objects in the message RAM; the CANMSG2INT register contains the IntPnd bit of the second 16 message objects. CAN Message 1 Interrupt Pending (CANMSG1INT) CAN0 base: 0x4004.0000 Offset 0x140 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset IntPnd Type Reset Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 IntPnd RO 0x00 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Interrupt Pending Bits (of all message objects) 0: This message object is not the source of an interrupt. 1: This message object is the source of an interrupt. 436 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 36: CAN Message 1 Valid (CANMSG1VAL), offset 0x160 Register 37: CAN Message 2 Valid (CANMSG2VAL), offset 0x164 The CANMSG1VAL and CANMSG2VAL registers hold the MsgVal bits of the 32 message objects. By reading these bits, the CPU can check which message object is valid. The message value of a specific message object can be changed with the CAN IFn Message Control (CANIFnMCTL) register. The CANMSG1VAL register contains the MsgVal bit of the first 16 message objects in the message RAM; the CANMSG2VAL register contains the MsgVal bit of the second 16 message objects in the message RAM CAN Message 1 Valid (CANMSG1VAL) CAN0 base: 0x4004.0000 Offset 0x160 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 MsgVal Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:16 reserved RO 0x0000 15:0 MsgVal RO 0x00 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Message Valid Bits (of all message objects) 0: This message object is not configured and is ignored by the message handler. 1: This message object is configured and should be considered by the message handler. June 14, 2007 437 Luminary Micro Confidential-Advance Product Information Ethernet Controller 17 Ethernet Controller ENET ® The Stellaris Ethernet Controller consists of a fully integrated media access controller (MAC) and network physical (PHY) interface device. The Ethernet controller conforms to IEE 802.3 specifications and fully supports 10BASE-T and 100BASE-TX standards. The Ethernet controller module has the following features: ■ Conforms to the IEEE 802.3-2002 specification – 10BASE-T/100BASE-TX IEEE-802.3 compliant. Requires only a dual 1:1 isolation transformer interface to the line. – 10BASE-T/100BASE-TX ENDEC, 100BASE-TX scrambler/descrambler – Full-featured auto-negotiation ■ Multiple operational modes – Full- and half-duplex 100 Mbps – Full- and half-duplex 10 Mbps – Power-saving and power-down modes ■ Highly configurable – Programmable MAC address – LED activity selection – Promiscuous mode support – CRC error-rejection control – User-configurable interrupts ■ Physical media manipulation – Automatic MDI/MDI-X cross-over correction – Register-programmable transmit amplitude – Automatic polarity correction and 10BASE-T signal reception 438 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 17.1 Block Diagram Figure 17-1. Ethernet Controller Block Diagram Interrupt Interrupt Control Receive Control MACISR MACRCR MACIACK MACIMR MACNPR TXOP Transmit FIFO Data Access System Clock Transmit Encoding Pulse Shaping Collision Detect Carrier Sense Receive Decoding Clock Recovery TXON MDIX MACDR RXIP Timer Support Transmit Control MACTSR MACTCR Receive FIFO RXIN MACITHR MACTRR MII Control Individual Address MACIAR0 MACIAR1 17.2 Media Independent Interface Management Register Set MACMCR MACMDVR MACMAR MACMDTX MACMDRX MR0 MR1 MR2 MR3 MR4 MR5 MR6 MR16 MR17 MR18 MR19 MR23 MR24 Auto Negotiation XTLP Clock Reference XTLN Functional Description As illustrated in Figure 17-2 on page 439, the Ethernet Controller is functionally divided into two layers or modules - the Media Access Controller (MAC) layer and Network Physical (PHY) layer. These correspond to the OSI model layers 2 and 1. The primary interface to the Ethernet controller is a simple bus interface to the MAC layer. The MAC layer provides transmit and receive processing for ethernet frames. The MAC layer also provides the interface to the PHY module via an internal Media Independent Interface (MII). Figure 17-2. Ethernet Controller Ethernet Controller Cortex M3 17.2.1 Media Access Controller Physical Layer Entity MAC (Layer 2) PHY (Layer 1) Magnetics RJ45 Internal MII Operation For the MII management interface to function properly, the MDIO signal must be connected through a 10k Ω pull-up resistor to the +3.3V supply. Failure to connect this pull-up resistor will prevent management transactions on this internal MII to function. Note that it is possible for data transmission across the MII to still function since the PHY layer will auto-negotiate the link parameters by default. June 14, 2007 439 Luminary Micro Confidential-Advance Product Information Ethernet Controller For the MII management interface to function properly, the internal clock must be divided down from the system clock to a frequency no greater than 2.5 MHz. The MACMDV register contains the divider used for scaling down the system clock. See page 458 for more details about the use of this register. 17.2.2 PHY Configuration/Operation The Physical Layer (PHY) in the Ethernet controller includes integrated ENDECs, scrambler/descrambler, dual-speed clock recovery, and full-featured auto-negotiation functions. The transmitter includes an on-chip pulse shaper and a low-power line driver. The receiver has an adaptive equalizer and a baseline restoration circuit required for accurate clock and data recovery. The transceiver interfaces to Category-5 unshielded twisted pair (Cat-5 UTP) cabling for 100BASE-TX applications, and Category-3 unshielded twisted pair (Cat-3 UTP) for 10BASE-T applications. The Ethernet Controller is connected to the line media via dual 1:1 isolation transformers. No external filter is required. 17.2.2.1 Clock Selection The PHY has an on-chip crystal oscillator which can also be driven by an external oscillator. In this mode of operation, a 25-MHz crystal should be connected between the XTLPPHY and XTLNPHY pins. Alternatively, an external 25-MHz clock input can be connected to the XTLP pin. In this mode of operation, a crystal is not required and the XTLN pin must be tied to ground. 17.2.2.2 Auto-Negotation The PHY supports the auto-negotiation functions of Clause 28 of the IEEE 802.3 standard for 10/100 Mbps operation over copper wiring. This function can be enabled via register settings. The autonegotiation function defaults to On and bit 12 (ANEGEN) in the MR0 register is High after reset. Software can disable the auto-negotiation function by writing to the ANEGEN bit. The contents of the MR4 register are sent to the PHY’s link partner during auto-negotiation via fast-link pulse coding. Once auto-negotiation is complete, bits 11:10 (DPLX and RATE) in the MR18 register reflect the actual speed and duplex that was chosen. If auto-negotiation fails to establish a link for any reason, bit 12 (ANEGF) in the MR18 register reflects this and auto-negotiation restarts from the beginning. Writing a 1 to bit 9 (RANEG) in the MR0 register also causes auto-negotiation to restart. 17.2.2.3 Polarity Correction The PHY is capable of either automatic or manual polarity reversal for 10BASE-T and auto-negotiation functions. Bits 4 and 5 (RVSPOL and APOL) in the MR16 register control this feature. The default is automatic mode, where APOL is Low and RVSPOL indicates if the detection circuitry has inverted the input signal. To enter manual mode, APOL should be set High and RVSPOL then controls the signal polarity. 17.2.2.4 MDI/MDI-X Configuration The PHY supports the automatic MDI/MDI-X configuration as defined in IEEE 802.3 2002. This eliminates the need for cross-over cables when connecting to another devices, such as a hub. The algorithm is controlled via settings in the MR24 register. Refer to page 481 for additional details about these settings. 17.2.2.5 LED Indicators The PHY supports two LED signals that can be used to indicate various states of operation of the Ethernet Controller. These signals are mapped to the LED0 and LED1 pins. By default, these pins are configured as GPIO signals (PF3 and PF2). For the PHY layer to drive these signals, they must be reconfigured to their hardware function. Refer to the GIPO chapter for additional details. The 440 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller function of these pins is programmable via the PHY layer MR23 register. Refer to page 480 for additonal details on how to program these LED functions. 17.2.3 MAC Configuration/Operation 17.2.3.1 Ethernet Frame Format Ethernet data is carried by Ethernet frames. The basic frame format is shown in Figure 17-3 on page 441. Figure 17-3. Ethernet Frame Preamble 7 Bytes SFD Destination Address 1 Byte 6 Bytes Source Address Length/ Type Data FCS 6 Bytes 2 Bytes 46 - 1500 Bytes 4 Bytes The seven fields of the frame are transmitted from left to right. The bits within the frame are transmitted from least to most significant bit. ■ Preamble The Preamble field is used by the physical layer signaling circuitry to synchronize with the received frame’s timing. The preamble is 7 octets long. ■ Start Frame Delimiter (SFD) The SFD field follows the preamble pattern and indicates the start of the frame. Its value is 1010.1011. ■ Destination Address (DA) This field specifies destination addresses for which the frame is intended. The LSB of the DA determines whether the address is an individual (0), or group/multicast (1) address. ■ Source Address (SA) The source address field identifies the station from which the frame was initiated. ■ Length/Type Field The meaning of this field depends on its numeric value. The first of two octets is most significant. This field can be interpreted as length or type code. The maximum length of the data field is 1500 octets. If the value of the Length/Type field is less than or equal to 1500 decimal, it indicates the number of MAC client data octets. If the value of this field is greater than or equal to 1536 decimal, then it is type interpretation. The meaning of the Length/Type field when the value is between 1500 and 1536 decimal is unspecified by the standard. The MAC module assumes type interpretation if the value of the Length/Type field is greater than 1500 decimal. ■ Data The data field is a sequence of 0 to 1500 octets. Full data transparency is provided so any values can appear in this field. A minimum frame size is required to properly meet the IEEE standard. If necessary, the data field is extended by appending extra bits (a pad). The pad field can have a size of 0 to 46 octets. The sum of the data and pad lengths must be a minimum of 46 octets. The MAC module automatically inserts pads if required, though it can be disabled by a register June 14, 2007 441 Luminary Micro Confidential-Advance Product Information Ethernet Controller write. For the MAC module core, data sent/received can be larger than 1500 bytes, and no Frame Too Long error is reported. Instead, a FIFO Overrun error is reported when the frame received is too large to fit into the Ethernet controller’s RAM. ■ Frame Check Sequence (FCS) The frame check sequence carries the CRC (cyclic redundancy check value). The value of this field is computed over destination address, source address, length/type, data, and pad fields using the CRC-32 algorithm. The MAC module computes the FCS value one nibble at a time. For transmitted frames, this field is automatically inserted by the MAC layer, unless disabled by the CRC bit in the MACTCTL register. For received frames, this field is automatically checked. If the FCS does not pass, the frame will not be placed in the RX FIFO, unless the FCS check is disabled by the BADCRC bit in the MACRCTL register. 17.2.3.2 MAC Layer FIFOs For Ethernet frame transmission, a 2K Byte TX FIFO is provided that can be used to store a single frame. While the IEEE 802.3 specification limits the size of an Ethernet frame's payload section to 1500 Bytes, the Ethernet controller places no such limit. The full buffer can be used, for a paylload of up to 2032 bytes. For ethernet frame reception, a 2K Byte RX FIFO is provided that can be used to store multiple frames, up to a maximum of 31 frames. If a frame is received and there is insufficient space in the RX FIFO, an overflow error will be indicated. For details regarding the TX and RX FIFO layout, refer to Table 17-1 on page 442. Please note the following difference between TX and RX FIFO layout. For the TX FIFO, the Data Length field in the first FIFO word refers to the Ethernet frame data payload, as shown in the 5th to nth FIFO positions. For the RX FIFO, the Frame Lenth field is the total length of the receieved ethernet frame, including the FCS and Frame Length bytes. Also note that if FCS generation is disabled with the CRC bit in the MACTCTL register, the last word in the FIFO must be the FCS bytes for the frame that has been written to the FIFO. Also note that if the length of the data payload section is not a multiple of 4, the FCS field will overlap words in the FIFO. However, for the RX FIFO, the beginning of the next frame will always be on a word boundary. Table 17-1. TX & RX FIFO Organization FIFO Word Read/Write Sequence Word Bit Fields TX FIFO (Write) RX FIFO (Read) 1st 7:0 Data Length LSB Frame Length LSB 15:8 Data Length MSB Frame Length MSB 2nd 3rd 23:16 DA oct 1 31:24 DA oct 2 7:0 DA oct 3 15:8 DA oct 4 23:16 DA oct 5 31:24 DA oct 6 7:0 SA oct 1 15:8 SA oct 2 23:16 SA oct 3 31:24 SA oct 4 442 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller FIFO Word Read/Write Sequence Word Bit Fields 4th 7:0 SA oct 5 15:8 SA oct 6 23:16 Len/Type MSB 31:24 Len/Type LSB 5th to nth TX FIFO (Write) 7:0 data oct n 15:8 data oct n+1 23:16 data oct n+2 31:24 last RX FIFO (Read) data oct n+3 7:0 FCS 1 (if CRC generation is disabled in MACTCTL) FCS 1 15:8 FCS 2 (if CRC generation is disabled in MACTCTL) FCS 2 23:16 FCS 3 (if CRC generation is disabled in MACTCTL) FCS 3 31:24 FCS 4 (if CRC generation is disabled in MACTCTL) FCS 4 17.2.3.3 Ethernet Transmission Options The ethernet controller can automatically generate and insert the Frame Check Sequence (FCS) at the end of the transmit frame. This is controlled by the CRC bit in the MACTCTL register. For test purposes, in order to generate a frame with an invalid CRC, this feature can be disabled. The IEEE 802.3 specification requires that the ethernet frame payload section be a minimum of 46 bytes. The ethernet controller can be configured to automatically pad the data section if the payload data section loaded into the FIFO is less than the minimum 46 bytes. This feature is controlled by the PADEN bit in the MACTCTL register. At the MAC layer, the transmitter can be configured for both full-duplex and half-duplex operation by using the DUPLEX bit in the MACTCTL register. 17.2.3.4 Ethernet Reception Options Using the BADCRC bit in the MACRCTL register, the ethernet controller can be configured to reject incoming ethernet frames with an invalid Frame Check Sequence field. The ethernet receiver can also be configured for Promiscuous and Multicast modes using the PRMS and AMUL fields in the MACRCTL register. If these modes are not enabled, only ethernet frames with a broadcast address, or frames matching the MAC address programmed into the MACIA0 and MACIA1 register will be placed into the RX FIFO. 17.2.4 Interrupts The ethernet controller can generate an interrupt for one or more of the following conditions. ■ A frame has been received into an empty RX FIFO. ■ A frame transmission error has occurred ■ A frame has been transmitted successfully. ■ A frame has been received with no room in the RX FIFO (overrun). June 14, 2007 443 Luminary Micro Confidential-Advance Product Information Ethernet Controller ■ A frame has been received with one or more error conditions (e.g. FCS failed). ■ An MII management transaction between the MAC and PHY layers has completed. ■ One or more of the following PHY layer conditions occurs. – Auto Negotiate Complete – Remote Fault – Link Status Change – Link Partner Acknowledge – Parallel Detect Fault – Page Received – Receive Error – Jabber Event Detected 17.3 Initialization and Configuration To use the Ethernet Controller, the peripheral must be enabled by setting the ETH bits in the RCGC2 register. The following steps can then be used to configure the ethernet controller for basic operation. 1. Program the MACDIV register to obtain a 2.5 MHz clock (or less) on the internal MII. Assuming a 20 MHz system clock, the MACDIV value would be 4. 2. Program the MACIA0 and MACIA1 register for address filtering. 3. Program the MACTCTL register for Auto CRC generation, padding, and full duplex operation using a value of 0x16. 4. Program the MACRCTL register to reject frames with bad FCS using a value of 0x08. 5. Enable both the Transmitter and Receive by setting the LSB in both the MACTCTL and MACRCTL register. 6. To transmit a frame, write the frame into the TX FIFO using the MACDATA register. Then set the NEWTX bit in the MACTR register to initiate the transmit process. When the NEWTX bit has been cleared, the TX FIFO will be available for the next transmit frame. 7. To receive a frame, wait for the NPR field in the MACNP register to be non-zero. Then begin reading the frame from the RX FIFO by using the MACDATA register. When the frame (including the FCS field) has been read, the NPR field should decrement by one. When there are no more frames in the RX FIFO, the NPR field will read 0. 17.4 Ethernet Register Map Table 17-2 on page 445 lists the Ethernet MAC registers. All addresses given are relative to the Ethernet MAC base address of 0x4004.8000. The IEEE 802.3 standard specifies a register set for controlling and gathering status from the PHY. The registers are collectively known as the MII Management registers and are detailed in Section 444 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 22.2.4 of the IEEE 802.3 specification. Table 17-2 on page 445 lists the MII Management registers. All addresses given are absolute and are written directly to the REGADR field of the MACMCTL register. The format of registers 0 to 15 are defined by the IEEE specification and are common to all PHY implementations. The only variance allowed is for features that may or may not be supported by a specific PHY. Registers 16 to 31 are vendor-specific registers, used to support features that are specific to a vendors PHY implementation. Vendor-specific registers not listed are reserved. Table 17-2. Ethernet Register Map Offset Name Description See page Type Reset RO 0x0000.0000 Ethernet MAC Raw Interrupt Status 447 Ethernet MAC 0x000 MACRIS 0x000 MACIACK W1C 0x0000.0000 Ethernet MAC Interrupt Acknowledge 449 0x004 MACIM R/W 0x0000.007F Ethernet MAC Interrupt Mask 450 0x008 MACRCTL R/W 0x0000.0008 Ethernet MAC Receive Control 451 0x00C MACTCTL R/W 0x0000.0000 Ethernet MAC Transmit Control 452 0x010 MACDATA R/W 0x0000.0000 Ethernet MAC Data 453 0x014 MACIA0 R/W 0x0000.0000 Ethernet MAC Individual Address 0 454 0x018 MACIA1 R/W 0x0000.0000 Ethernet MAC Individual Address 1 455 0x01C MACTHR R/W 0x0000.003F Ethernet MAC Threshold 456 0x020 MACMCTL R/W 0x0000.0000 Ethernet MAC Management Control 457 0x024 MACMDV R/W 0x0000.0080 Ethernet MAC Management Divider 458 0x028 MACMADD RO 0x0000.0000 Ethernet MAC Management Address 459 0x02C MACMTXD R/W 0x0000.0000 Ethernet MAC Management Transmit Data 460 0x030 MACMRXD R/W 0x0000.0000 Ethernet MAC Management Receive Data 461 0x034 MACNP RO 0x0000.0000 Ethernet MAC Number of Packets 462 0x038 MACTR R/W 0x0000.0000 Ethernet MAC Transmission Request 463 MII Management 0x00 MR0 R/W 0x3100 Ethernet PHY Management Register 0 – Control 464 0x01 MR1 RO 0x7849 Ethernet PHY Management Register 1 – Status 466 0x02 MR2 RO 0x000E Ethernet PHY Management Register 2 – PHY Identifier 1 468 0x03 MR3 RO 0x7237 Ethernet PHY Management Register 3 – PHY Identifier 2 469 0x04 MR4 R/W 0x01E1 Ethernet PHY Management Register 4 – Auto-Negotiation Advertisement 470 0x05 MR5 RO 0x0000 Ethernet PHY Management Register 5 – Auto-Negotiation Link Partner Base Page Ability 472 0x06 MR6 RO 0x0000 Ethernet PHY Management Register 6 – Auto-Negotiation Expansion 473 June 14, 2007 445 Luminary Micro Confidential-Advance Product Information Ethernet Controller See page Offset Name Type Reset Description 0x10 MR16 R/W 0x0140 Ethernet PHY Management Register 16 – Vendor-Specific 474 0x11 MR17 R/W 0x0000 Ethernet PHY Management Register 17 – Interrupt Control/Status 476 0x12 MR18 RO 0x0000 Ethernet PHY Management Register 18 – Diagnostic 478 0x13 MR19 R/W 0x4000 Ethernet PHY Management Register 19 – Transceiver Control 479 0x17 MR23 R/W 0x0010 Ethernet PHY Management Register 23 – LED Configuration 480 0x18 MR24 R/W 0x00C0 Ethernet PHY Management Register 24 –MDI/MDIX Control 481 17.5 Ethernet MAC Register Descriptions The remainder of this section lists and describes the Ethernet MAC registers, in numerical order by address offset. 446 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 1: Ethernet MAC Raw Interrupt Status (MACRIS), offset 0x000 The MACRIS register is the interrupt status register. On a read, this register gives the current status value of the corresponding interrupt prior to masking. Ethernet MAC Raw Interrupt Status (MACRIS) Base 0x4004.8000 Offset 0x000 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 PHYINT MDINT RXER FOV TXEMP TXER RXINT RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset Description 31:7 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 PHYINT RO 0x0 When set, indicates that an enabled interrupt in the PHY layer has occured. MR17 in the PHY must be read to determine the specific PHY event that triggered this interrupt. 5 MDINT RO 0x0 When set, indicates that a transaction (read or write) on the MII interface has completed successfully. 4 RXER RO 0x0 This bit indicates that an error was encountered on the receiver. The possible errors that can cause this interrupt bit to be set are: ■ A receive error occurs during the reception of a frame (100 Mb/s only). ■ The frame is not an integer number of bytes (dribble bits) due to an alignment error. ■ The CRC of the frame does not pass the FCS check. ■ The length/type field is inconsistent with the frame data size when interpreted as a length field. 3 FOV RO 0x0 When set, indicates that an overrun was encountered on the receive FIFO. 2 TXEMP RO 0x0 When set, indicates that the packet was transmitted and that the TX FIFO is empty. 1 TXER RO 0x0 When set, indicates that an error was encountered on the transmitter. The possible errors that can cause this interrupt bit to be set are: ■ The data length field stored in the TX FIFO exceeds 2032. The frame is not sent when this error occurs. ■ The retransmission attempts during the backoff process have exceeded the maximum limit of 16. June 14, 2007 447 Luminary Micro Confidential-Advance Product Information Ethernet Controller Bit/Field Name Type Reset 0 RXINT RO 0x0 Description When set, indicates that at least one packet has been received and is stored in the receiver FIFO. 448 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: Ethernet MAC Interrupt Acknowledge (MACIACK), offset 0x000 A write of a 1 to any bit position of this register clears the corresponding interrupt bit in the Ethernet MAC Raw Interrupt Status (MACRIS) register. Ethernet MAC Interrupt Acknowledge (MACIACK) Base 0x4004.8000 Offset 0x000 Type W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 MDINT RXER FOV TXEMP TXER RXINT RO 0 RO 0 RO 0 W1C 0 W1C 0 W1C 0 W1C 0 W1C 0 W1C 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset Description 31:6 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 PHYINT W1C 0x0 A write of a 1 to the PHYINT bit clears the PHYINT interrupt read from the MACRIS register. 5 MDINT W1C 0x0 A write of a 1 to the MDINT bit clears the MDINT interrupt read from the MACRIS register. 4 RXER W1C 0x0 A write of a 1 to the RXER bit clears the RXER interrupt read from the MACRIS register. 3 FOV W1C 0x0 A write of a 1 to the FOV bit clears the FOV interrupt read from the MACRIS register. 2 TXEMP W1C 0x0 A write of a 1 to the TXEMP bit clears the TXEMP interrupt read from the MACRIS register. 1 TXER W1C 0x0 A write of a 1 to the TXER bit clears the TXER interrupt read from the MACRIS register and resets the TX FIFO write pointer. 0 RXINT W1C 0x0 A write of a 1 to the RXINT bit clears the RXINT interrupt read from the MACRIS register. June 14, 2007 449 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 3: Ethernet MAC Interrupt Mask (MACIM), offset 0x004 This register allows software to enable/disable Ethernet MAC interrupts. Writing a 0 disables the interrupt, while writing a 1 enables it. Ethernet MAC Interrupt Mask (MACIM) Base 0x4004.8000 Offset 0x004 Type R/W, reset 0x0000.007F 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 PHYINTM MDINTM RXERM R/W 1 R/W 1 R/W 1 FOVM R/W 1 TXEMPM TXERM R/W 1 R/W 1 RXINTM R/W 1 Bit/Field Name Type Reset Description 31:7 reserved RO 0x0 6 PHYINTM R/W 1 The PHYINTM bit masks the PHYINT bit in the MACRIS register from being asserted. 5 MDINTM R/W 1 The MDINTM bit masks the MDINT bit in the MACRIS register from being asserted. 4 RXERM R/W 1 The RXERM bit masks the RXER bit in the MACRIS register from being asserted. 3 FOVM R/W 1 The FOVM bit masks the FOV bit in the MACRIS register from being asserted. 2 TXEMPM R/W 1 The TXEMPM bit masks the TXEMP bit in the MACRIS register from being asserted. 1 TXERM R/W 1 The TXERM bit masks the TXER bit in the MACRIS register from being asserted. 0 RXINTM R/W 1 The RXINTM bit masks the RXINT bit in the MACRIS register from being asserted. Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 450 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 4: Ethernet MAC Receive Control (MACRCTL), offset 0x008 This register enables software to configure the receive module and control the types of frames that are received from the physical medium. It is important to note that when the receive module is enabled, all valid frames with a broadcast address of FF-FF-FF-FF-FF-FF in the Destination Address field will be received and stored in the RX FIFO, even if the AMUL bit is not set. Ethernet MAC Receive Control (MACRCTL) Base 0x4004.8000 Offset 0x008 Type R/W, reset 0x0000.0008 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 PRMS AMUL RXEN RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 RSTFIFO BADCRC R/W 0 R/W 1 Bit/Field Name Type Reset Description 31:5 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 RSTFIFO R/W 0x0 When set, clears the receive FIFO. This should be done when software initialization is performed. It is recommended that the receiver be disabled (RXEN = 0), and then the reset initiated (RSTFIFO = 1). This sequence will flush and reset the RX FIFO. 3 BADCRC R/W 0x1 The BADCRC bit enables the rejection of frames with an incorrectly calculated CRC. 2 PRMS R/W 0x0 The PRMS bit enables Promiscuous mode, which accepts all valid frames, regardless of the Destination Address. 1 AMUL R/W 0x0 The AMUL bit enables the reception of multicast frames from the physical medium. 0 RXEN R/W 0x0 The RXEN bit enables the Ethernet receiver. When this bit is Low, the receiver is disabled and all frames on the physical medium are ignored. June 14, 2007 451 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 5: Ethernet MAC Transmit Control (MACTCTL), offset 0x00C This register enables software to configure the transmit module, and control frames are placed onto the physical medium. Ethernet MAC Transmit Control (MACTCTL) Base 0x4004.8000 Offset 0x00C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 CRC PADEN TXEN RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 DUPLEX reserved R/W 0 RO 0 Bit/Field Name Type Reset Description 31:5 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 DUPLEX R/W 0x0 When set, enables Duplex mode, allowing simultaneous transmission and reception. 3 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 CRC R/W 0x0 When set, enables the automatic generation of the CRC and the placement at the end of the packet. If this bit is not set, the frames placed in the TX FIFO will be sent exactly as they are written into the FIFO. 1 PADEN R/W 0x0 When set, enables the automatic padding of packets that do not meet the minimum frame size. 0 TXEN R/W 0x0 When set, enables the transmitter. When this bit is 0, the transmitter is disabled. 452 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 6: Ethernet MAC Data (MACDATA), offset 0x010 This register enables software to access the TX and RX FIFOs. Reads from this register return the data stored in the RX FIFO from the location indicated by the read pointer. Writes to this register store the data in the TX FIFO at the location indicated by the write pointer. The write pointer is then auto-incremented to the next TX FIFO location. There is no mechanism for randomly accessing bytes in either the RX or TX FIFOs. Data must be read from the RX FIFO sequentially and stored in a buffer for further processing. Once a read has been performed, the data in the FIFO cannot be re-read. Data must be written to the TX FIFO sequentially. If an error is made in placing the frame into the TX FIFO, the write pointer can be reset to the start of the TX FIFO by writing the TXER bit of the MACIACK register and the data re-written. Ethernet MAC Data (MACDATA) Base 0x4004.8000 Offset 0x010 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 R 0 R 0 R 0 R 0 R 0 R 0 R 0 R 0 7 6 5 4 3 2 1 0 R 0 R 0 R 0 R 0 R 0 R 0 R 0 R 0 RXDATA Type Reset R 0 R 0 R 0 R 0 R 0 R 0 R 0 R 0 15 14 13 12 11 10 9 8 RXDATA Type Reset R 0 R 0 R 0 R 0 R 0 R 0 R 0 Bit/Field Name Type Reset 31:0 RXDATA R 0x0 R 0 Description The RXDATA bits represent the next four bytes of data stored in the RX FIFO. Ethernet MAC Data (MACDATA) Base 0x4004.8000 Offset 0x010 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 15 14 13 12 11 10 9 8 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 23 22 21 20 19 18 17 16 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 7 6 5 4 3 2 1 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 TXDATA Type Reset TXDATA Type Reset Bit/Field Name Type Reset 31:0 TXDATA W 0x0 Description The TXDATA bits represent the next four bytes of data to place in the TX FIFO for transmission. June 14, 2007 453 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 7: Ethernet MAC Individual Address 0 (MACIA0), offset 0x014 This register enables software to program the first four bytes of the hardware MAC Address of the Network Interface Card (NIC). The 6-byte IAR is compared against the incoming Destination Address fields to determine whether the frame should be received. Ethernet MAC Individual Address 0 (MACIA0) Base 0x4004.8000 Offset 0x014 Type R/W, reset 0x0000.0000 31 30 29 28 R/W 0 R/W 0 R/W 0 R/W 0 15 14 13 12 R/W 0 R/W 0 R/W 0 R/W 0 27 26 25 24 23 22 21 20 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 11 10 9 8 7 6 5 4 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 MACOCT4 Type Reset R/W 0 18 17 16 R/W 0 R/W 0 R/W 0 R/W 0 3 2 1 0 R/W 0 R/W 0 R/W 0 MACOCT3 MACOCT2 Type Reset 19 MACOCT1 R/W 0 Bit/Field Name Type Reset Description 31:24 MACOCT4 R/W 0x0 The MACOCT4 bits represent the fourth octet of the MAC address used to uniquely identify each Ethernet Controller. 23:16 MACOCT3 R/W 0x0 The MACOCT3 bits represent the third octet of the MAC address used to uniquely identify each Ethernet Controller. 15:8 MACOCT2 R/W 0x0 The MACOCT2 bits represent the second octet of the MAC address used to uniquely identify each Ethernet Controller. 7:0 MACOCT1 R/W 0x0 The MACOCT1 bits represent the first octet of the MAC address used to uniquely identify each Ethernet Controller. 454 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 8: Ethernet MAC Individual Address 1 (MACIA1), offset 0x018 This register enables software to program the last two bytes of the hardware MAC Address of the Network Interface Card (NIC). The 6-byte IAR is compared against the incoming Destination Address fields to determine whether the frame should be received. Ethernet MAC Individual Address 1 (MACIA1) Base 0x4004.8000 Offset 0x018 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset MACOCT6 Type Reset R/W 0 MACOCT5 R/W 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:8 MACOCT6 R/W 0x0 The MACOCT6 bits represent the sixth octet of the MAC address used to uniquely identify each Ethernet Controller. 7:0 MACOCT5 R/W 0x0 The MACOCT5 bits represent the fifth octet of the MAC address used to uniquely identify each Ethernet Controller. June 14, 2007 455 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 9: Ethernet MAC Threshold (MACTHR), offset 0x01C This register enables software to set the threshold level at which the transmission of the frame begins. If the THRESH bits are set to 0x3F, which is the reset value, transmission does not start until the NEWTX bit is set in the MACTR register. This effectively disables the early transmission feature. Writing the THRESH bits to any value besides all 1s enables the early transmission feature. Once the byte count of data in the TX FIFO reaches this level, transmission of the frame begins. When THRESH is set to all 0s, transmission of the frame begins after 4 bytes (a single write) are stored in the TX FIFO. Each increment of the THRESH bit field waits for an additional 32 bytes of data (eight writes) to be stored in the TX FIFO. Therefore, a value of 0x01 would wait for 36 bytes of data to be written while a value of 0x02 would wait for 68 bytes to be written. In general, early transmission starts when: Number of Bytes ≥ 4 (THRESH x 8 + 1) Reaching the threshold level has the same effect as setting the NEWTX bit in the MACTR register. Transmission of the frame begins and then the number of bytes indicated by the Data Length field is sent out on the physical medium. Because under-run checking is not performed, it is possible that the tail pointer may reach and pass the write pointer in the TX FIFO. This causes indeterminate values to be written to the physical medium rather than the end of the frame. Therefore, sufficient bus bandwidth for writing to the TX FIFO must be guaranteed by the software. If a frame smaller than the threshold level needs to be sent, the NEWTX bit in the MACTR register must be set with an explicit write. This initiates the transmission of the frame even though the threshold limit has not been reached. If the threshold level is set too small, it is possible for the transmitter to underrun. If this occurs, the transmit frame will be aborted, and a transmit error will be indicated. Ethernet MAC Threshold (MACTHR) Base 0x4004.8000 Offset 0x01C Type R/W, reset 0x0000.003F 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 R/W 1 reserved Type Reset reserved Type Reset RO 0 THRESH Bit/Field Name Type Reset Description 31:6 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5:0 THRESH R/W 0x3F The THRESH bits represent the early transmit threshold. Once the amount of data in the TX FIFO exceeds this value, transmission of the packet begins. 456 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 10: Ethernet MAC Management Control (MACMCTL), offset 0x020 This register enables software to control the transfer of data to and from the MII Management Registers in the Ethernet PHY. The address, name, type, reset configuration, and functional description of each of these registers can be found in Table 17-2 on page 445 and “MII Management Register Descriptions” on page 463. In order to initiate a read transaction from the MII Management registers, the WRITE bit must be written with a 0 during the same cycle that the START bit is written with a 1. In order to initiate a write transaction to the MII Management registers, the WRITE bit must be written with a 1 during the same cycle that the START bit is written with a 1. Ethernet MAC Management Control (MACMCTL) Base 0x4004.8000 Offset 0x020 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 reserved WRITE START RO 0 R/W 0 R/W 0 R/W 0 R/W 0 RO 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset REGADR RO 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:3 REGADR R/W 0x0 The REGADR bit field represents the MII Management register address for the next MII management interface transaction. 2 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 WRITE R/W 0x0 The WRITE bit represents the operation of the next MII management interface transaction. If WRITE is set, the next operation will be a write; otherwise, it will be a read. 0 START R/W 0x0 The START bit represents the initiation of the next MII management interface transaction. When a 1 is written to this bit, the MII register located at REGADR will be read (WRITE=0) or written (WRITE=1). June 14, 2007 457 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 11: Ethernet MAC Management Divider (MACMDV), offset 0x024 This register enables software to set the clock divider for the Management Data Clock (MDC). This clock is used to synchronize read and write transactions between the system and the MII Management registers. The frequency of the MDC clock can be calculated from the following formula: Fmdc = Fipclk / (2 * (MACMDVR + 1 )) The clock divider must be written with a value that ensures that the MDC clock will not exceed a frequency of 2.5 MHz. Ethernet MAC Management Divider (MACMDV) Base 0x4004.8000 Offset 0x024 Type R/W, reset 0x0000.0080 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 R/W 1 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset DIV RO 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:0 DIV R/W 0x80 The DIV bits are used to set the clock divider for the MDC clock used to transmit data between the MAC and PHY over the serial MII interface. 458 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 12: Ethernet MAC Management Address (MACMADD), offset 0x028 This register enables software to choose the address of the PHY for the next MII Management register transaction. Ethernet MAC Management Address (MACMADD) Base 0x4004.8000 Offset 0x028 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset 31:0 reserved RO 0x0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 459 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 13: Ethernet MAC Management Transmit Data (MACMTXD), offset 0x02C This register holds the next value to be written to the MII Management registers. Ethernet MAC Management Transmit Data (MACMTXD) Base 0x4004.8000 Offset 0x02C Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 MDTX Type Reset R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 MDTX R/W 0x0 The MDTX bits represent the data that will be written in the next MII management transaction. 460 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 14: Ethernet MAC Management Receive Data (MACMRXD), offset 0x030 This register holds the last value read from the MII Management registers. Ethernet MAC Management Receive Data (MACMRXD) Base 0x4004.8000 Offset 0x030 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 MDRX Type Reset R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:0 MDRX R/W 0x0 The MDRX bits represent the data that was read in the previous MII management transaction. June 14, 2007 461 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 15: Ethernet MAC Number of Packets (MACNP), offset 0x034 This register holds the number of frames that are currently in the RX FIFO. When NPR is all 0s, there are no frames in the RX FIFO and the RXINT bit is not set. When NPR is any other value, there is at least one frame in the RX FIFO and the RXINT bit is set. Ethernet MAC Number of Packets (MACNP) Base 0x4004.8000 Offset 0x034 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 NPR Bit/Field Name Type Reset Description 31:6 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 5:0 NPR RO 0x0 The NPR bits represent the number of packets stored in the RX FIFO. While NPR is greater than 0, the RXINT interrupt will be asserted. 462 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 16: Ethernet MAC Transmission Request (MACTR), offset 0x038 This register enables software to initiate the transmission of the frame currently located in the TX FIFO to the physical medium. Once the frame has been transmitted to the medium from the TX FIFO or a transmission error has been encountered, the NEWTX bit is auto-cleared by the hardware. Ethernet MAC Transmission Request (MACTR) Base 0x4004.8000 Offset 0x038 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 NEWTX R/W 0 Bit/Field Name Type Reset 31:1 reserved RO 0x0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 0 NEWTX R/W 0x0 When set, the NEWTX bit initiates an Ethernet transmission once the packet has been placed in the TX FIFO. This bit is cleared once the transmission has been completed. If early transmission is being used (see the MACTHR register), this bit does not need to be set. 17.6 Description MII Management Register Descriptions The IEEE 802.3 standard specifies a register set for controlling and gathering status from the PHY. The registers are collectively known as the MII Management registers. All addresses given are absolute. Addresses not listed are reserved. June 14, 2007 463 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 17: Ethernet PHY Management Register 0 – Control (MR0), offset 0x00 This register enables software to configure the operation of the PHY. The default settings of these registers are designed to initialize the PHY to a normal operational mode without configuration. Ethernet PHY Management Register 0 – Control (MR0) Base 0x4004.8000 Offset 0x00 Type R/W, reset 0x3100 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 R/W 0 R/W 0 R/W 0 reserved Type Reset RO 0 15 RESET Type Reset R/W 0 RO 0 RO 0 RO 0 RO 0 14 13 12 11 LOOPBK SPEEDSL ANEGEN PWRDN R/W 0 R/W 1 R/W 1 R/W 0 RO 0 10 ISO R/W 0 RO 0 RO 0 9 8 RANEG DUPLEX R/W 0 R/W 1 COLT R/W 0 reserved R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15 RESET R/W 0 Reset Registers When set, resets the registers to their default state and reinitializes internal state machines. Once the reset operation has completed, this bit is cleared by hardware. 14 LOOPBK R/W 0 Loopback Mode When set, enables the Loopback mode of operation. The receive circuitry is isolated from the physical medium and transmissions are sent back through the receive circuitry instead of the medium. 13 SPEEDSL R/W 1 Speed Select 1: Enables the 100 Mb/s mode of operation (100BASE-TX). 0: Enables the 10 Mb/s mode of operation (10BASE-T). 12 ANEGEN R/W 1 Auto-Negotiation Enable When set, enables the Auto-Negotiation process. 11 PWRDN R/W 0 Power Down When set, places the PHY into a low-power consuming state. 10 ISO R/W 0 Isolate When set, isolates transmit and receive data paths and ignores all signaling on these buses. 9 RANEG R/W 0 Restart Auto-Negotiation When set, restarts the Auto-Negotiation process. Once the restart has initiated, this bit is cleared by hardware. 464 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 8 DUPLEX R/W 1 Description Set Duplex Mode 1: Enables the Full-Duplex mode of operation. This bit can be set by software in a manual configuration process or by the Auto-Negotiation process. 0: Enables the Half-Duplex mode of operation. 7 COLT R/W 0 Collision Test When set, enables the Collision Test mode of operation. The COLT bit asserts after the initiation of a transmission and de-asserts once the transmission is halted. 6:0 reserved R/W 0x00 Write as 0, ignore on read. June 14, 2007 465 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 18: Ethernet PHY Management Register 1 – Status (MR1), offset 0x01 This register enables software to determine the capabilities of the PHY and perform its initialization and operation appropriately. Ethernet PHY Management Register 1 – Status (MR1) Base 0x4004.8000 Offset 0x01 Type RO, reset 0x7849 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 reserved 100X_F 100X_H 10T_F 10T_H RO 0 RO 1 RO 1 RO 1 RO 1 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 MFPS ANEGC RFAULT ANEGA LINK JAB EXTD RO 0 RO 0 RO 1 RO 0 RC 0 RO 1 RO 0 RC 0 RO 1 reserved Type Reset Type Reset reserved Bit/Field Name Type Reset Description 31:15 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 14 100X_F RO 1 100BASE-TX Full-Duplex Mode When set, indicates that the PHY is capable of supporting 100BASE-TX Full Duplex mode. 13 100X_H RO 1 100BASE-TX Half-Duplex Mode When set, indicates that the PHY is capable of supporting 100BASE-TX Half-Duplex mode. 12 10T_F RO 1 10BASE-T Full-Duplex Mode When set, indicates that the PHY is capable of 10BASE-T Full-Duplex mode. 11 10T_H RO 1 10BASE-T Half-Duplex Mode When set, indicates that the PHY is capable of supporting 10BASE-T Half-Duplex mode. 10:7 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 6 MFPS RO 1 Management Frames with Preamble Suppressed When set, indicates that the Management Interface is capable of receiving management frames with the preamble suppressed. 5 ANEGC RO 0 Auto-Negotiation Complete When set, indicates that the Auto-Negotiation process has been completed and that the extended registers defined by the Auto-Negotiation protocol are valid. 466 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 4 RFAULT RC 0 Description Remote Fault When set, indicates that a remote fault condition has been detected. This bit remains set until it is read, even if the condition no longer exists. 3 ANEGA RO 1 Auto-Negotiation When set, indicates that the PHY has the ability to perform Auto-Negotiation. 2 LINK RO 0 Link Made When set, indicates that a valid link has been established by the PHY. 1 JAB RC 0 Jabber Condition When set, indicates that a jabber condition has been detected by the PHY. This bit remains set until it is read, even if the jabber condition no longer exists. 0 EXTD RO 1 Extended Capabilities When set, indicates that the PHY provides an extended set of capabilities that can be accessed through the extended register set. June 14, 2007 467 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 19: Ethernet PHY Management Register 2 – PHY Identifier 1 (MR2), offset 0x02 This register, along with Management Register 3, provides a 32-bit value indicating the manufacturer, model, and revision information. Ethernet PHY Management Register 2 – PHY Identifier 1 (MR2) Base 0x4004.8000 Offset 0x02 Type RO, reset 0x000E 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 1 RO 1 RO 1 RO 0 OUI[21:6] Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset 31:16 reserved RO 0 15:0 OUI[21:6] RO 0x000E RO 0 RO 0 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Organizationally Unique Identifier[21:6] This field, along with the OUI[5:0] field in Management Register 3, makes up the Organizationally Unique Identifier indicating the PHY manufacturer. 468 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 20: Ethernet PHY Management Register 3 – PHY Identifier 2 (MR3), offset 0x03 This register, along with Management Register 2, provides a 32-bit value indicating the manufacturer, model, and revision information. Ethernet PHY Management Register 3 – PHY Identifier 2 (MR3) Base 0x4004.8000 Offset 0x03 Type RO, reset 0x7237 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 6 5 4 3 2 1 0 RO 1 RO 1 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 OUI[5:0] Type Reset RO 0 RO 1 RO 1 RO 1 MN RO 0 RO 0 RO 1 Bit/Field Name Type Reset 31:16 reserved RO 0 15:10 OUI[5:0] RO 0x1C RO 0 RO 0 RN RO 0 RO 1 RO 1 RO 0 RO 1 Description Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Organizationally Unique Identifier[5:0] This field, along with the OUI[21:6] field in Management Register 2, makes up the Organizationally Unique Identifier indicating the PHY manufacturer. 9:4 MN RO 0x23 Model Number The MN field represents the Model Number of the PHY. 3:0 RN RO 0x7 Revision Number The RN field represents the Revision Number of the PHY. June 14, 2007 469 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 21: Ethernet PHY Management Register 4 – Auto-Negotiation Advertisement (MR4), offset 0x04 This register provides the advertised abilities of the PHY used during Auto-Negotiation. Bits 12:5 represent the Technology Ability Field bits, A[7:0]. This field can be overwritten by software to Auto-Negotiate to an alternate common technology. Writing to this register has no effect until Auto-Negotiation is re-initiated. Ethernet PHY Management Register 4 – Auto-Negotiation Advertisement (MR4) Base 0x4004.8000 Offset 0x04 Type R/W, reset 0x01E1 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 4 3 2 1 0 RO 0 RO 1 reserved Type Reset RO 0 Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 12 11 10 9 15 14 13 NP reserved RF RO 0 RO 0 R/W 0 reserved RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 A3 A2 A1 A0 R/W 1 R/W 1 R/W 1 R/W 1 S[4:0] RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15 NP RO 0 Next Page When set, indicates the PHY is capable of Next Page exchanges to provide more detailed information on the PHY’s capabilities. 14 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 13 RF R/W 0 Remote Fault When set, indicates to the link partner that a Remote Fault condition has been encountered. 12:9 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 8 A3 R/W 1 Technology Ability Field[3] When set, indicates that the PHY supports the 100Base-TX Full-Duplex signaling protocol. If software wants to ensure that this mode is not used, this bit can be written to 0 and Auto-Negotiation re-initiated with the RANEG bit. 7 A2 R/W 1 Technology Ability Field[2] When set, indicates that the PHY supports the 100Base-T half-duplex signaling protocol. If software wants to ensure that this mode is not used, this bit can be written to 0 and Auto-Negotiation re-initiated. 470 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 6 A1 R/W 1 Description Technology Ability Field[1] When set, indicates that the PHY supports the 10Base-T Full-Duplex signaling protocol. If software wants to ensure that this mode is not used, this bit can be written to 0 and Auto-Negotiation re-initiated. 5 A0 R/W 1 Technology Ability Field[0] When set, indicates that the PHY supports the 10Base-T half-duplex signaling protocol. If software wants to ensure that this mode is not used, this bit can be written to 0 and Auto-Negotiation re-initiated. 4:0 S[4:0] RO 0x01 Selector Field The S[4:0] field encodes 32 possible messages for communicating between PHYs. This field is hard-coded to 0x01, indicating that the ® Stellaris PHY is IEEE 802.3 compliant. June 14, 2007 471 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 22: Ethernet PHY Management Register 5 – Auto-Negotiation Link Partner Base Page Ability (MR5), offset 0x05 This register provides the advertised abilities of the link partner’s PHY that are received and stored during Auto-Negotiation. Ethernet PHY Management Register 5 – Auto-Negotiation Link Partner Base Page Ability (MR5) Base 0x4004.8000 Offset 0x05 Type RO, reset 0x0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 2 1 0 RO 0 RO 0 reserved Type Reset Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 12 11 10 9 15 14 13 NP ACK RF RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 A[7:0] RO 0 RO 0 RO 0 RO 0 S[4:0] RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15 NP RO 0 Next Page When set, indicates that the link partner’s PHY is capable of Next page exchanges to provide more detailed information on the PHY’s capabilities. 14 ACK RO 0 Acknowledge When set, indicates that the device has successfully received the link partner’s advertised abilities during Auto-Negotiation. 13 RF RO 0 Remote Fault Used as a standard transport mechanism for transmitting simple fault information. 12:5 A[7:0] RO 0x00 Technology Ability Field The A field encodes individual technologies that are supported by the PHY. See the MR4 register. 4:0 S[4:0] RO 0x00 Selector Field The S field encodes possible messages for communicating between PHYs. Value Meaning 0x00 Reserved 0x01 IEEE Std 802.3 0x02 IEEE Std 802.9 ISLAN-16T 0x03 IEEE Std 802.5 0x04 IEEE Std 1394 0x05 – 0x1F Reserved 472 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 23: Ethernet PHY Management Register 6 – Auto-Negotiation Expansion (MR6), offset 0x06 This register enables software to determine the Auto-Negotiation and Next Page capabilities of the PHY and the link partner after Auto-Negotiation. Ethernet PHY Management Register 6 – Auto-Negotiation Expansion (MR6) Base 0x4004.8000 Offset 0x06 Type RO, reset 0x0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 10 9 8 7 6 5 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 4 3 2 1 0 PDF LPNPA reserved PRX LPANEGA RC 0 RO 0 RO 0 RC 0 RO 0 Bit/Field Name Type Reset Description 31:5 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 4 PDF RC 0 Parallel Detection Fault When set, indicates that more than one technology has been detected at link up. This bit is cleared when read. 3 LPNPA RO 0 Link Partner is Next Page Able When set, indicates that the link partner is Next Page Able. 2 reserved RO 0x000 1 PRX RC 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. New Page Received When set, indicates that a New Page has been received from the link partner and stored in the appropriate location. This bit remains set until the register is read. 0 LPANEGA RO 0 Link Partner is Auto-Negotiation Able When set, indicates that the Link partner is Auto-Negotiation Able. June 14, 2007 473 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 24: Ethernet PHY Management Register 16 – Vendor-Specific (MR16), offset 0x10 This register enables software to configure the operation of vendor specific modes of the PHY. Ethernet PHY Management Register 16 – Vendor-Specific (MR16) Base 0x4004.8000 Offset 0x10 Type R/W, reset 0x0140 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 3 2 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 9 8 7 6 15 14 13 12 11 10 RPTR INPOL reserved TXHIM SQEI NL10 R/W 0 R/W 0 RO 0 R/W 0 R/W 0 R/W 0 Type Reset reserved RO 0 RO 1 RO 0 RO 1 5 4 APOL RVSPOL R/W 0 R/W 0 reserved RO 0 RO 0 1 0 PCSBP RXCC R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15 RPTR R/W 0 Repeater Mode When set, enables the repeater mode of operation. In this mode, full-duplex is not allowed and the Carrier Sense signal only responds to receive activity. If the PHY is configured to 10Base-T mode, the SQE test function is disabled. 14 INPOL R/W 0 Interrupt Polarity 1: Sets the polarity of the PHY interrupt to be active High. 0: Sets the polarity of the PHY interrupt to active Low. Important: Because the Media Access Controller expects active Low interrupts from the PHY, this bit must always be written with a 0 to ensure proper operation. 13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 TXHIM R/W 0 Transmit High Impedance Mode When set, enables the transmitter High Impedance mode. In this mode, the TXOP and TXON transmitter pins are put into a high impedance state. The RXIP and RXIN pins remain fully functional. 11 SQEI R/W 0 SQE Inhibit Testing When set, prohibits 10Base-T SQE testing. When 0, the SQE testing is performed by generating a Collision pulse following the completion of the transmission of a frame. 474 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 10 NL10 R/W 0 Description Natural Loopback Mode When set, enables the 10Base-T Natural Loopback mode. This causes the transmission data received by the PHY to be looped back onto the receive data path when 10Base-T mode is enabled. 9:6 reserved RO 0x05 5 APOL R/W 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. Auto-Polarity Disable When set, disables the PHY’s auto-polarity function. If this bit is 0, the PHY automatically inverts the received signal due to a wrong polarity connection during Auto-Negotiation if the PHY is in 10Base-T mode. 4 RVSPOL R/W 0 Receive Data Polarity This bit indicates whether the receive data pulses are being inverted. If the APOL bit is 0, then the RVSPOL bit is read-only and indicates whether the auto polarity circuitry is reversing the polarity. In this case, a 1 in the RVSPOL bit indicates that the receive data is inverted while a 0 indicates that the receive data is not inverted. If the APOL bit is set, then the RVSPOL bit is writable and software can force the receive data to be inverted. Setting RVSPOL to 1 forces the receive data to be inverted while a 0 does not invert the receive data. 3:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 PCSBP R/W 0 PCS Bypass When set, enables the bypass of the PCS and scrambling/descrambling functions in 100Base-TX mode. This mode is only valid when Auto-Negotiation is disabled and 100Base-T mode is enabled. 0 RXCC R/W 0 Receive Clock Control When set, enables the Receive Clock Control power saving mode if the PHY is configured in 100Base-TX mode. This mode shuts down the receive clock when no data is being received from the physical medium to save power. This mode should not be used when PCSBP is enabled and is automatically disabled when the LOOPBK bit in the MR0 register is set. June 14, 2007 475 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 25: Ethernet PHY Management Register 17 – Interrupt Control/Status (MR17), offset 0x11 This register provides the means for controlling and observing the events, which trigger a PHY interrupt in the MACRIS register. This register can also be used in a polling mode via the MII Serial Interface as a means to observe key events within the PHY via one register address. Bits 0 through 7 are status bits, which are each set to logic 1 based on an event. These bits are cleared after the register is read. Bits 8 through 15 of this register, when set to logic 1, enable their corresponding bit in the lower byte to signal a PHY interrupt in the MACRIS register. Ethernet PHY Management Register 17 – Interrupt Control/Status (MR17) Base 0x4004.8000 Offset 0x11 Type R/W, reset 0x0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 15 14 13 JABBER_IE RXER_IE PRX_IE Type Reset R/W 0 R/W 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 12 11 10 9 8 7 6 5 4 3 2 1 0 PDF_IE LPACK_IE LSCHG_IE RFAULT_IE ANEGCOMP_IE JABBER_INT RXER_INT PRX_INT PDF_INT LPACK_INT LSCHG_INT RFAULT_INT ANEGCOMP_N IT R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 R/W 0 RC 0 RC 0 RC 0 RC 0 RC 0 RC 0 RC 0 RC 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15 JABBER_IE R/W 0 Jabber Interrupt Enable When set, enables system interrupts when a Jabber condition is detected by the PHY. 14 RXER_IE R/W 0 Receive Error Interrupt Enable When set, enables system interrupts when a receive error is detected by the PHY. 13 PRX_IE R/W 0 Page Received Interrupt Enable When set, enables system interrupts when a new page is received by the PHY. 12 PDF_IE R/W 0 Parallel Detection Fault Interrupt Enable When set, enables system interrupts when a Parallel Detection Fault is detected by the PHY. 11 LPACK_IE R/W 0 LP Acknowledge Interrupt Enable When set, enables system interrupts when FLP bursts are received with the Acknowledge bit during Auto-Negotiation. 10 LSCHG_IE R/W 0 Link Status Change Interrupt Enable When set, enables system interrupts when the Link Status changes from OK to FAIL. 476 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Bit/Field Name Type Reset 9 RFAULT_IE R/W 0 Description Remote Fault Interrupt Enable When set, enables system interrupts when a Remote Fault condition is signaled by the link partner. 8 ANEGCOMP_IE R/W 0 Auto-Negotiation Complete Interrupt Enable When set, enables system interrupts when the Auto-Negotiation sequence has completed successfully. 7 JABBER_INT RC 0 Jabber Event Interrupt When set, indicates that a Jabber event has been detected by the 10Base-T circuitry. 6 RXER_INT RC 0 Receive Error Interrupt When set, indicates that a receive error has been detected by the PHY. 5 PRX_INT RC 0 Page Receive Interrupt When set, indicates that a new page has been received from the link partner during Auto-Negotiation. 4 PDF_INT RC 0 Parallel Detection Fault Interrupt When set, indicates that a Parallel Detection Fault has been detected by the PHY during the Auto-Negotiation process. 3 LPACK_INT RC 0 LP Acknowledge Interrupt When set, indicates that an FLP burst has been received with the Acknowledge bit set during Auto-Negotiation. 2 LSCHG_INT RC 0 Link Status Change Interrupt When set, indicates that the link status has changed from OK to FAIL. 1 RFAULT_INT RC 0 Remote Fault Interrupt When set, indicates that a Remote Fault condition has been signaled by the link partner. 0 ANEGCOMP_INT RC 0 Auto-Negotiation Complete Interrupt When set, indicates that the Auto-Negotiation sequence has completed successfully. June 14, 2007 477 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 26: Ethernet PHY Management Register 18 – Diagnostic (MR18), offset 0x12 This register enables software to diagnose the results of the previous Auto-Negotiation. Ethernet PHY Management Register 18 – Diagnostic (MR18) Base 0x4004.8000 Offset 0x12 Type RO, reset 0x0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 15 RO 0 RO 0 14 13 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 12 11 10 9 8 ANEGF DPLX RATE RXSD RX_LOCK RC 0 RO 0 RO 0 RO 0 RO 0 reserved RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:13 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 12 ANEGF RC 0 Auto-Negotiation Failure When set, indicates that no common technology was found during Auto-Negotiation and has failed. This bit remains set until read. 11 DPLX RO 0 Duplex Mode When set, indicates that Full-Duplex was the highest common denominator found during the Auto-Negotiation process. Otherwise, Half-Duplex was the highest common denominator found. 10 RATE RO 0 Rate When set, indicates that 100Base-TX was the highest common denominator found during the Auto-Negotiation process. Otherwise, 10Base-TX was the highest common denominator found. 9 RXSD RO 0 Receive Detection When set, indicates that receive signal detection has occurred (in 100Base-TX mode) or that Manchester encoded data has been detected (in 10Base-T mode). 8 RX_LOCK RO 0 Receive PLL Lock When set, indicates that the Receive PLL has locked onto the receive signal for the selected speed of operation (10Base-T or 100Base-TX). 7:0 reserved RO 00 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 478 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 27: Ethernet PHY Management Register 19 – Transceiver Control (MR19), offset 0x13 This register enables software to set the gain of the transmit output to compensate for transformer loss. Ethernet PHY Management Register 19 – Transceiver Control (MR19) Base 0x4004.8000 Offset 0x13 Type R/W, reset 0x4000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 TXO[1:0] Type Reset R/W 0 R/W 1 reserved RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 Bit/Field Name Type Reset Description 31:16 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 15:14 TXO[1:0] R/W 1 Transmit Amplitude Selection The TXO field sets the transmit output amplitude to account for transmit transformer insertion loss. Value Meaning 13:0 reserved RO 0x0 00 Gain set for 0.0dB of insertion loss 01 Gain set for 0.4dB of insertion loss 10 Gain set for 0.8dB of insertion loss 11 Gain set for 1.2dB of insertion loss Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. June 14, 2007 479 Luminary Micro Confidential-Advance Product Information Ethernet Controller Register 28: Ethernet PHY Management Register 23 – LED Configuration (MR23), offset 0x17 This register enables software to select the source that will cause the LEDs to toggle. Ethernet PHY Management Register 23 – LED Configuration (MR23) Base 0x4004.8000 Offset 0x17 Type R/W, reset 0x0010 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 LED1[3:0] RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 LED0[3:0] R/W 1 R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7:4 LED1[3:0] R/W 1 The LED1 field selects the source that will toggle the LED1 signal. Value Meaning 0000 Link OK 0001 RX or TX Activity (Default LED1) 0010 TX Activity 0011 RX Activity 0100 Collision 0101 100BASE-TX mode 0110 10BASE-T mode 0111 Full Duplex 1000 Link OK & Blink=RX or TX Activity 3:0 LED0[3:0] R/W 0 The LED0 field selects the source that will toggle the LED0 signal. Value Meaning 0000 Link OK (Default LED0) 0001 RX or TX Activity 0010 TX Activity 0011 RX Activity 0100 Collision 0101 100BASE-TX mode 0110 10BASE-T mode 0111 Full Duplex 1000 Link OK & Blink=RX or TX Activity 480 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 29: Ethernet PHY Management Register 24 –MDI/MDIX Control (MR24), offset 0x18 This register enables software to control the behavior of the MDI/MDIX mux and its switching capabilities. Ethernet PHY Management Register 24 –MDI/MDIX Control (MR24) Base 0x4004.8000 Offset 0x18 Type R/W, reset 0x00C0 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 3 2 1 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 8 reserved Type Reset RO 0 RO 0 RO 0 RO 0 PD_MODE AUTO_SW RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 5 4 MDIX MDIX_CM R/W 0 RO 0 MDIX_SD R/W 0 R/W 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7 PD_MODE R/W 0 Parallel Detection Mode When set, enables the Parallel Detection mode and allows auto-switching to work when Auto-Negotiation is not enabled. 6 AUTO_SW R/W 0 Auto-Switching Enable When set, enables Auto-Switching of the MDI/MDIX mux. 5 MDIX R/W 0 Auto-Switching Configuration When set, indicates that the MDI/MDIX mux is in the crossover (MDIX) configuration. When 0, it indicates that the mux is in the pass-through (MDI) configuration. When the AUTO_SW bit is 1, the MDIX bit is read-only. When the AUTO_SW bit is 0, the MDIX bit is read/write and can be configured manually. 4 MDIX_CM RO 0 Auto-Switching Complete When set, indicates that the auto-switching sequence has completed. If 0, it indicates that the sequence has not completed or that auto-switching is disabled. 3:0 MDIX_SD R/W 0 Auto-Switching Seed This field provides the initial seed for the switching algorithm. This seed directly affects the number of attempts [5,4] respectively to write bits [3:0]. A 0 sets the seed to 0x5. June 14, 2007 481 Luminary Micro Confidential-Advance Product Information Analog Comparators 18 Analog Comparators ACMP An analog comparator is a peripheral that compares two analog voltages, and provides a logical output that signals the comparison result. The LM3S8938 controller provides three independent integrated analog comparators that can be configured to drive an output or generate an interrupt or ADC event. Note: Not all comparators have the option to drive an output pin. See the Comparator Operating Mode tables for more information. A comparator can compare a test voltage against any one of these voltages: ■ An individual external reference voltage ■ A shared single external reference voltage ■ A shared internal reference voltage The comparator can provide its output to a device pin, acting as a replacement for an analog comparator on the board, or it can be used to signal the application via interrupts or triggers to the ADC to cause it to start capturing a sample sequence. The interrupt generation and ADC triggering logic is separate. This means, for example, that an interrupt can be generated on a rising edge and the ADC triggered on a falling edge. 482 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 18.1 Block Diagram Figure 18-1. Analog Comparator Module Block Diagram C2- -ve input C2+ +ve input Comparator 2 output +ve input (alternate) trigger ACCTL2 ACSTAT2 interrupt reference input C1- -ve input C1+ +ve input C2o trigger interrupt Comparator 1 output C1o +ve input (alternate) ACCTL1 trigger ACSTAT1 interrupt reference input C0- -ve input C0+ +ve input trigger interrupt Comparator 0 output +ve input (alternate) trigger ACCTL0 ACSTAT0 interrupt reference input C0o trigger interrupt Voltage Ref internal bus 18.2 ACREFCTL Functional Description Important: It is recommended that the Digital-Input enable (the GPIODEN bit in the GPIO module) for the analog input pin be disabled to prevent excessive current draw from the I/O pads. The comparator compares the VIN- and VIN+ inputs to produce an output, VOUT. VIN- < VIN+, VOUT = 1 VIN- > VIN+, VOUT = 0 As shown in Figure 18-2 on page 484, the input source for VIN- is an external input. In addition to an external input, input sources for VIN+ can be the +ve input of comparator 0 or an internal reference. June 14, 2007 483 Luminary Micro Confidential-Advance Product Information Analog Comparators Figure 18-2. Structure of Comparator Unit -ve input output 0 CINV 1 +ve input (alternate) IntGen 2 reference input TrigGen ACCTL trigger internal bus ACSTAT interrupt +ve input A comparator is configured through two status/control registers (ACCTL and ACSTAT ). The internal reference is configured through one control register (ACREFCTL). Interrupt status and control is configured through three registers (ACMIS, ACRIS, and ACINTEN). The operating modes of the comparators are shown in the Comparator Operating Mode tables. Typically, the comparator output is used internally to generate controller interrupts. It may also be used to drive an external pin or generate an analog-to-digital converter (ADC) trigger. Important: Certain register bit values must be set before using the analog comparators. The proper pad configuration for the comparator input and output pins are described in the Comparator Operating Mode tables. Table 18-1. Comparator 0 Operating Modes ACCNTL0 Comparator 0 ASRCP VIN- VIN+ 00 C0- C0+ Output Interrupt ADC Trigger C0o yes yes 01 C0- C0+ C0o yes yes 10 C0- Vref C0o yes yes 11 C0- reserved C0o yes yes Table 18-2. Comparator 1 Operating Modes ACCNTL1 Comparator 1 ASRCP VIN- VIN+ Output a Interrupt ADC Trigger 00 C1- C1o/C1+ C1o/C1+ yes yes 01 C1- C0+ C1o/C1+ yes yes 10 C1- Vref C1o/C1+ yes yes 11 C1- reserved C1o/C1+ yes yes a. C1o and C1+ signals share a single pin and may only be used as one or the other. 484 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Table 18-3. Comparator 2 Operating Modes ACCNTL2 Comparator 2 ASRCP VIN- VIN+ 00 C2- C2o/C2+ C2o/C2+ Output yes yes 01 C2- C0+ C2o/C2+ yes yes 10 C2- Vref C2o/C2+ yes yes 11 C2- reserved C2o/C2+ yes yes a Interrupt ADC Trigger a. C2o and C2+ signals share a single pin and may only be used as one or the other. 18.2.1 Internal Reference Programming The structure of the internal reference is shown in Figure 18-3 on page 485. This is controlled by a single configuration register (ACREFCTL). Table 18-4 on page 485 shows the programming options to develop specific internal reference values, to compare an external voltage against a particular voltage generated internally. Figure 18-3. Comparator Internal Reference Structure 8R AVDD 8R R R R R ••• EN 15 14 ••• 1 0 Decoder VREF internal reference RNG Table 18-4. Internal Reference Voltage and ACREFCTL Field Values ACREFCTL Register Output Reference Voltage Based on VREF Field Value EN Bit Value RNG Bit Value EN=0 RNG=X 0 V (GND) for any value of VREF; however, it is recommended that RNG=1 and VREF=0 for the least noisy ground reference. June 14, 2007 485 Luminary Micro Confidential-Advance Product Information Analog Comparators ACREFCTL Register Output Reference Voltage Based on VREF Field Value EN Bit Value RNG Bit Value EN=1 RNG=0 Total resistance in ladder is 32 R. V V V REF = AV REF R EF = AV DD DD R ------× ------V----REF R T ( V REF + 8) × -----------------------------32 = 0.825 + 0.103 V REF The range of internal reference in this mode is 0.825-2.37 V. RNG=1 Total resistance in ladder is 24 R. V V REF REF = AV = AV DD DD R ------× ------V----REF R T ( V REF ) × --------------------24 VREF = 0.1375 x VREF The range of internal reference for this mode is 0.0-2.0625 V. 18.3 Initialization and Configuration The following example shows how to configure an analog comparator to read back its output value from an internal register. 1. Enable the analog comparator 0 clock by writing a value of 0x0010.0000 to the RCGC1 register in the System Control module. 2. In the GPIO module, enable the GPIO port/pin associated with C0- as a GPIO input. 3. Configure the internal voltage reference to 1.65 V by writing the ACREFCTL register with the value 0x0000.030C. 4. Configure comparator 0 to use the internal voltage reference and to not invert the output on the C0o pin by writing the ACCTL0 register with the value of 0x0000.040C. 5. Delay for some time. 6. Read the comparator output value by reading the ACSTAT0 register’s OVAL value. Change the level of the signal input on C0- to see the OVAL value change. 18.4 Register Map Table 18-5 on page 487 lists the comparator registers. The offset listed is a hexadecimal increment to the register’s address, relative to the Analog Comparator base address of 0x4003.C000. 486 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Table 18-5. Analog Comparators Register Map Name Type Reset 0x00 ACMIS R/W1C 0x0000.0000 Analog Comparator Masked Interrupt Status 488 0x04 ACRIS RO 0x0000.0000 Analog Comparator Raw Interrupt Status 489 0x08 ACINTEN R/W 0x0000.0000 Analog Comparator Interrupt Enable 490 0x10 ACREFCTL R/W 0x0000.0000 Analog Comparator Reference Voltage Control 491 0x20 ACSTAT0 RO 0x0000.0000 Analog Comparator Status 0 492 0x24 ACCTL0 R/W 0x0000.0000 Analog Comparator Control 0 493 0x40 ACSTAT1 RO 0x0000.0000 Analog Comparator Status 1 492 0x44 ACCTL1 R/W 0x0000.0000 Analog Comparator Control 1 493 0x60 ACSTAT2 RO 0x0000.0000 Analog Comparator Status 2 492 0x64 ACCTL2 R/W 0x0000.0000 Analog Comparator Control 2 493 18.5 Description See page Offset Register Descriptions The remainder of this section lists and describes the Analog Comparator registers, in numerical order by address offset. June 14, 2007 487 Luminary Micro Confidential-Advance Product Information Analog Comparators Register 1: Analog Comparator Masked Interrupt Status (ACMIS), offset 0x00 This register provides a summary of the interrupt status (masked) of the comparator. Analog Comparator Masked Interrupt Status (ACMIS) Base 0x4003.C000 Offset 0x00 Type R/W1C, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 IN2 IN1 IN0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W1C 0 R/W1C 0 R/W1C 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 IN2 R/W1C 0 Comparator 2 Masked Interrupt Status Gives the masked interrupt state of this interrupt. Write 1 to this bit to clear the pending interrupt. 1 IN1 R/W1C 0 Comparator 1 Masked Interrupt Status Gives the masked interrupt state of this interrupt. Write 1 to this bit to clear the pending interrupt. 0 IN0 R/W1C 0 Comparator 0 Masked Interrupt Status Gives the masked interrupt state of this interrupt. Write 1 to this bit to clear the pending interrupt. 488 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 2: Analog Comparator Raw Interrupt Status (ACRIS), offset 0x04 This register provides a summary of the interrupt status (raw) of the comparator. Analog Comparator Raw Interrupt Status (ACRIS) Base 0x4003.C000 Offset 0x04 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 IN2 IN1 IN0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 IN2 RO 0 When set, indicates that an interrupt has been generated by comparator 2. 1 IN1 RO 0 When set, indicates that an interrupt has been generated by comparator 1. 0 IN0 RO 0 When set, indicates that an interrupt has been generated by comparator 0. June 14, 2007 489 Luminary Micro Confidential-Advance Product Information Analog Comparators Register 3: Analog Comparator Interrupt Enable (ACINTEN), offset 0x08 This register provides the interrupt enable for the comparator. Analog Comparator Interrupt Enable (ACINTEN) Base 0x4003.C000 Offset 0x08 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 IN2 IN1 IN0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 R/W 0 R/W 0 R/W 0 reserved Type Reset reserved Type Reset RO 0 Bit/Field Name Type Reset Description 31:3 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 2 IN2 R/W 0 When set, enables the controller interrupt from the comparator 2 output 1 IN1 R/W 0 When set, enables the controller interrupt from the comparator 1 output. 0 IN0 R/W 0 When set, enables the controller interrupt from the comparator 0 output. 490 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 4: Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x10 This register specifies whether the resistor ladder is powered on as well as the range and tap. Analog Comparator Reference Voltage Control (ACREFCTL) Base 0x4003.C000 Offset 0x10 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 RO 0 RO 0 1 0 R/W 0 R/W 0 reserved Type Reset RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 7 6 5 4 3 2 9 8 EN RNG R/W 0 R/W 0 reserved Type Reset RO 0 reserved RO 0 RO 0 RO 0 VREF RO 0 R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:10 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 9 EN R/W 0 The EN bit specifies whether the resistor ladder is powered on. If 0, the resistor ladder is unpowered. If 1, the resistor ladder is connected to the analog VDD. This bit is reset to 0 so that the internal reference consumes the least amount of power if not used and programmed. 8 RNG R/W 0 The RNG bit specifies the range of the resistor ladder. If 0, the resistor ladder has a total resistance of 32 R. If 1, the resistor ladder has a total resistance of 24 R. 7:4 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 3:0 VREF R/W 0 The VREF bit field specifies the resistor ladder tap that is passed through an analog multiplexer. The voltage corresponding to the tap position is the internal reference voltage available for comparison. See Table 18-4 on page 485 for some output reference voltage examples. June 14, 2007 491 Luminary Micro Confidential-Advance Product Information Analog Comparators Register 5: Analog Comparator Status 0 (ACSTAT0), offset 0x20 Register 6: Analog Comparator Status 1 (ACSTAT1), offset 0x40 Register 7: Analog Comparator Status 2 (ACSTAT2), offset 0x60 These registers specify the current output value of the comparator. Analog Comparator Status 0 (ACSTAT0) Base 0x4003.C000 Offset 0x20 Type RO, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 OVAL reserved RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 reserved Type Reset reserved Type Reset Bit/Field Name Type Reset Description 31:2 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 1 OVAL RO 0 The OVAL bit specifies the current output value of the comparator. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 492 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Register 8: Analog Comparator Control 0 (ACCTL0), offset 0x24 Register 9: Analog Comparator Control 1 (ACCTL1), offset 0x44 Register 10: Analog Comparator Control 2 (ACCTL2), offset 0x64 These registers configure the comparator’s input and output. Analog Comparator Control 0 (ACCTL0) Base 0x4003.C000 Offset 0x24 Type R/W, reset 0x0000.0000 31 30 29 28 27 26 25 24 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 15 14 13 12 11 10 9 RO 0 RO 0 23 22 21 20 19 18 17 16 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 RO 0 8 7 6 5 4 3 2 1 0 reserved TSLVAL CINV reserved RO 0 R/W 0 R/W 0 RO 0 reserved Type Reset reserved Type Reset RO 0 TOEN RO 0 R/W 0 ASRCP R/W 0 R/W 0 TSEN R/W 0 ISLVAL R/W 0 R/W 0 ISEN R/W 0 R/W 0 Bit/Field Name Type Reset Description 31:12 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 11 TOEN R/W 0 The TOEN bit enables the ADC event transmission to the ADC. If 0, the event is suppressed and not sent to the ADC. If 1, the event is transmitted to the ADC. 10:9 ASRCP R/W 0 The ASRCP field specifies the source of input voltage to the VIN+ terminal of the comparator. The encodings for this field are as follows: ASRCP Function 00 Pin value 01 Pin value of C0+ 10 Internal voltage reference 11 Reserved 8 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 7 TSLVAL R/W 0 The TSLVAL bit specifies the sense value of the input that generates an ADC event if in Level Sense mode. If 0, an ADC event is generated if the comparator output is Low. Otherwise, an ADC event is generated if the comparator output is High. June 14, 2007 493 Luminary Micro Confidential-Advance Product Information Analog Comparators Bit/Field Name Type Reset 6:5 TSEN R/W 0 Description The TSEN field specifies the sense of the comparator output that generates an ADC event. The sense conditioning is as follows: TSEN Function 00 Level sense, see TSLVAL 01 Falling edge 10 Rising edge 11 Either edge 4 ISLVAL R/W 0 The ISLVAL bit specifies the sense value of the input that generates an interrupt if in Level Sense mode. If 0, an interrupt is generated if the comparator output is Low. Otherwise, an interrupt is generated if the comparator output is High. 3:2 ISEN R/W 0 The ISEN field specifies the sense of the comparator output that generates an interrupt. The sense conditioning is as follows: ISEN Function 00 Level sense, see ISLVAL 01 Falling edge 10 Rising edge 11 Either edge 1 CINV R/W 0 The CINV bit conditionally inverts the output of the comparator. If 0, the output of the comparator is unchanged. If 1, the output of the comparator is inverted prior to being processed by hardware. 0 reserved RO 0 Software should not rely on the value of a reserved bit. To provide compatibility with future products, the value of a reserved bit should be preserved across a read-modify-write operation. 494 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 19 Pin Diagram Figure 19-1 on page 495 shows the pin diagram and pin-to-signal-name mapping. Figure 19-1. Pin Connection Diagram June 14, 2007 495 Luminary Micro Confidential-Advance Product Information Signal Tables 20 Signal Tables The following tables list the signals available for each pin. Functionality is enabled by software with the GPIOAFSEL register. Important: All multiplexed pins are GPIOs by default, with the exception of the five JTAG pins (PB7 and PC[3:0]) which default to the JTAG functionality. Table 20-1 on page 496 shows the pin-to-signal-name mapping, including functional characteristics of the signals. Table 20-2 on page 500 lists the signals in alphabetical order by signal name. Table 20-3 on page 504 groups the signals by functionality, except for GPIOs. Table 20-4 on page 508 lists the GPIO pins and their alternate functionality. Table 20-1. Signals by Pin Number Pin Number Pin Name Pin Type 1 ADC0 I Analog Analog-to-digital converter input 0. 2 ADC1 I Analog Analog-to-digital converter input 1. 3 VDDA - Power The positive supply (3.3 V) for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. 4 GNDA - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. 5 ADC2 I Analog Analog-to-digital converter input 2. 6 ADC3 I Analog Analog-to-digital converter input 3. 7 LDO - Power Low drop-out regulator output voltage. This pin requires an external capacitor between the pin and GND of 1 µF or greater. When the on-chip LDO is used to provide power to the logic, the LDO pin must also be connected to the VDD25 pins at the board level in addition to the decoupling capacitor(s). 8 VDD - Power Positive supply for I/O and some logic. 9 GND - Power Ground reference for logic and I/O pins. 10 CAN0Rx I TTL CAN module 0 receive PD0 I/O TTL GPIO port D bit 0 CAN0Tx O TTL CAN module 0 transmit PD1 I/O TTL GPIO port D bit 1 PD2 I/O TTL GPIO port D bit 2 U1Rx I TTL UART module 1 receive. When in IrDA mode, this signal has IrDA modulation. PD3 I/O TTL GPIO port D bit 3 U1Tx O TTL UART module 1 transmit. When in IrDA mode, this signal has IrDA modulation. 11 12 13 Buffer Type Description 496 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Pin Number Pin Name Pin Type 14 VDD25 - Power Positive supply for most of the logic function, including the processor core and most peripherals. 15 GND - Power Ground reference for logic and I/O pins. 16 XTALPPHY O TTL XTALP of the Ethernet PHY 17 XTALNPHY I TTL XTALN of the Ethernet PHY 18 Buffer Type Description PG1 I/O TTL GPIO port G bit 1 U2Tx O TTL UART 2 Transmit. When in IrDA mode, this signal has IrDA modulation. PG0 I/O TTL GPIO port G bit 0 U2Rx I TTL UART 2 Receive. When in IrDA mode, this signal has IrDA modulation. 20 VDD - Power Positive supply for I/O and some logic. 21 GND - Power Ground reference for logic and I/O pins. 22 C2- I Analog Analog comparator 2 negative input PC7 I/O TTL C2+ I Analog C2o O TTL Analog comparator 2 output PC6 I/O TTL GPIO port C bit 6 C1+ I Analog C1o O TTL Analog comparator 1 output 19 23 24 25 26 27 28 GPIO port C bit 7 Analog comparator positive input Analog comparator positive input PC5 I/O TTL GPIO port C bit 5 CCP5 I/O TTL Capture/Compare/PWM 5 PC4 I/O TTL GPIO port C bit 4 PA0 I/O TTL GPIO port A bit 0 U0Rx I TTL UART module 0 receive. When in IrDA mode, this signal has IrDA modulation. PA1 I/O TTL GPIO port A bit 1 U0Tx O TTL UART module 0 transmit. When in IrDA mode, this signal has IrDA modulation. PA2 I/O TTL GPIO port A bit 2 SSI0Clk I/O TTL SSI module 0 clock PA3 I/O TTL GPIO port A bit 3 SSI0Fss I/O TTL SSI module 0 frame PA4 I/O TTL GPIO port A bit 4 SSI0Rx I TTL SSI module 0 receive PA5 I/O TTL GPIO port A bit 5 SSI0Tx O TTL SSI module 0 transmit 32 VDD - Power Positive supply for I/O and some logic. 33 GND - Power Ground reference for logic and I/O pins. 34 I2C1SCL I/O OD I2C module 1 clock PA6 I/O TTL GPIO port A bit 6 I2C1SDA I/O OD I2C module 1 data PA7 I/O TTL GPIO port A bit 7 29 30 31 35 June 14, 2007 497 Luminary Micro Confidential-Advance Product Information Signal Tables Pin Number Pin Name Pin Type 36 VCCPHY I Buffer Type Description TTL VCC of the Ethernet PHY 37 RXIN I Analog RXIN of the Ethernet PHY 38 VDD25 - Power Positive supply for most of the logic function, including the processor core and most peripherals. 39 GND - Power Ground reference for logic and I/O pins. 40 RXIP I Analog RXIP of the Ethernet PHY 41 GNDPHY I TTL GND of the Ethernet PHY 42 GNDPHY I TTL GND of Ethernet PHY 43 TXOP O Analog TXOP of Ethernet PHY 44 VDD - Power Positive supply for I/O and some logic. 45 GND - Power Ground reference for logic and I/O pins. 46 TXON O Analog TXON of Ethernet PHY 47 PF0 I/O TTL 48 OSC0 I Analog Main oscillator crystal input or an external clock reference input. 49 OSC1 O Analog Main oscillator crystal output. 50 WAKE I OD An external input that brings the processor out of hibernate mode when asserted. 51 HIB O TTL An output that indicates the processor is in hibernate mode. 52 XOSC0 I Analog Hibernation Module oscillator crystal input or an external clock reference input. Note that this is either a 4.19-MHz crystal or a 32.768-kHz oscillator for the Hibernation Module RTC. See the CLKSEL bit in the HIBCTL register. 53 XOSC1 O Analog Hibernation Module oscillator crystal output. 54 GND - Power Ground reference for logic and I/O pins. 55 VBAT - Power Power source for the Hibernation Module. It is normally connected to the positive terminal of a battery and serves as the battery backup/Hibernation Module power-source supply. 56 VDD - Power Positive supply for I/O and some logic. Ground reference for logic and I/O pins. GPIO port F bit 0 57 GND - Power 58 MDIO I/O TTL MDIO of Ethernet PHY 59 LED0 O TTL MII LED 0 PF3 I/O TTL GPIO port F bit 3 60 LED1 O TTL MII LED 1 PF2 I/O TTL GPIO port F bit 2 61 PF1 I/O TTL GPIO port F bit 1 62 VDD25 - Power Positive supply for most of the logic function, including the processor core and most peripherals. 63 GND - Power Ground reference for logic and I/O pins. 64 RST I TTL System reset input. 498 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Pin Number Pin Name Pin Type 65 CMOD0 I/O TTL CPU Mode bit 0. Input must be set to logic 0 (grounded); other encodings reserved. 66 CCP0 I/O TTL Capture/Compare/PWM 0 PB0 I/O TTL GPIO port B bit 0 CCP2 I/O TTL Capture/Compare/PWM 2 PB1 I/O TTL GPIO port B bit 1 68 VDD - Power Positive supply for I/O and some logic. 69 GND - Power Ground reference for logic and I/O pins. 70 I2C0SCL I/O OD I2C module 0 clock PB2 I/O TTL GPIO port B bit 2 71 I2C0SDA I/O OD I2C module 0 data PB3 I/O TTL GPIO port B bit 3 CCP3 I/O TTL Capture/Compare/PWM 3 PE0 I/O TTL GPIO port E bit 0 73 PE1 I/O TTL GPIO port E bit 1 74 CCP4 I/O TTL Capture/Compare/PWM 4 PE2 I/O TTL GPIO port E bit 2 CCP1 I/O TTL Capture/Compare/PWM 1 PE3 I/O TTL GPIO port E bit 3 76 CMOD1 I/O TTL CPU Mode bit 1. Input must be set to logic 0 (grounded); other encodings reserved. 77 PC3 I/O TTL GPIO port C bit 3 SWO O TTL JTAG TDO and SWO TDO O TTL JTAG TDO and SWO PC2 I/O TTL GPIO port C bit 2 TDI I TTL JTAG TDI PC1 I/O TTL GPIO port C bit 1 SWDIO I/O TTL JTAG TMS and SWDIO TMS I/O TTL JTAG TMS and SWDIO 67 72 75 78 79 80 Buffer Type Description PC0 I/O TTL GPIO port C bit 0 SWCLK I TTL JTAG/SWD CLK TCK I TTL JTAG/SWD CLK 81 VDD - Power Positive supply for I/O and some logic. 82 GND - Power Ground reference for logic and I/O pins. 83 VCCPHY I TTL VCC of the Ethernet PHY 84 VCCPHY I TTL VCC of the Ethernet PHY 85 GNDPHY I TTL GND of the Ethernet PHY 86 GNDPHY I TTL GND of the Ethernet PHY 87 GND - Power Ground reference for logic and I/O pins. 88 VDD25 - Power Positive supply for most of the logic function, including the processor core and most peripherals. 89 PB7 I/O TTL GPIO port B bit 7 TRST I TTL JTAG TRSTn June 14, 2007 499 Luminary Micro Confidential-Advance Product Information Signal Tables Pin Number Pin Name Pin Type 90 C0+ I Analog C0o O TTL Analog comparator 0 output PB6 I/O TTL GPIO port B bit 6 C1- I Analog PB5 I/O TTL C0- I Analog PB4 I/O TTL 93 VDD - Power Positive supply for I/O and some logic. 94 GND - Power Ground reference for logic and I/O pins. 95 ADC7 I Analog Analog-to-digital converter input 7. 96 ADC6 I Analog Analog-to-digital converter input 6. 97 GNDA - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. 98 VDDA - Power The positive supply (3.3 V) for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. 99 ADC5 I Analog Analog-to-digital converter input 5. 100 ADC4 I Analog Analog-to-digital converter input 4. 91 92 Buffer Type Description Analog comparator 0 positive input Analog comparator 1 negative input GPIO port B bit 5 Analog comparator 0 negative input GPIO port B bit 4 Table 20-2. Signals by Signal Name Pin Name Pin Number Pin Type ADC0 1 I Buffer Type Description Analog Analog-to-digital converter input 0. ADC1 2 I Analog Analog-to-digital converter input 1. ADC2 5 I Analog Analog-to-digital converter input 2. ADC3 6 I Analog Analog-to-digital converter input 3. ADC4 100 I Analog Analog-to-digital converter input 4. ADC5 99 I Analog Analog-to-digital converter input 5. ADC6 96 I Analog Analog-to-digital converter input 6. ADC7 95 I Analog Analog-to-digital converter input 7. C0+ 90 I Analog Analog comparator 0 positive input C0- 92 I Analog Analog comparator 0 negative input C0o 90 O TTL C1+ 24 I Analog Analog comparator positive input C1- 91 I Analog Analog comparator 1 negative input C1o 24 O TTL C2+ 23 I Analog Analog comparator positive input C2- 22 I Analog Analog comparator 2 negative input C2o 23 O TTL Analog comparator 2 output CAN0Rx 10 I TTL CAN module 0 receive CAN0Tx 11 O TTL CAN module 0 transmit Analog comparator 0 output Analog comparator 1 output 500 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Pin Name Pin Number Pin Type CCP0 66 I/O Buffer Type Description TTL Capture/Compare/PWM 0 CCP1 75 I/O TTL Capture/Compare/PWM 1 CCP2 67 I/O TTL Capture/Compare/PWM 2 CCP3 72 I/O TTL Capture/Compare/PWM 3 CCP4 74 I/O TTL Capture/Compare/PWM 4 CCP5 25 I/O TTL Capture/Compare/PWM 5 CMOD0 65 I/O TTL CPU Mode bit 0. Input must be set to logic 0 (grounded); other encodings reserved. CMOD1 76 I/O TTL CPU Mode bit 1. Input must be set to logic 0 (grounded); other encodings reserved. GND 9 - Power Ground reference for logic and I/O pins. GND 15 - Power Ground reference for logic and I/O pins. GND 21 - Power Ground reference for logic and I/O pins. GND 33 - Power Ground reference for logic and I/O pins. GND 39 - Power Ground reference for logic and I/O pins. GND 45 - Power Ground reference for logic and I/O pins. GND 54 - Power Ground reference for logic and I/O pins. GND 57 - Power Ground reference for logic and I/O pins. GND 63 - Power Ground reference for logic and I/O pins. GND 69 - Power Ground reference for logic and I/O pins. GND 82 - Power Ground reference for logic and I/O pins. GND 87 - Power Ground reference for logic and I/O pins. GND 94 - Power Ground reference for logic and I/O pins. GNDA 4 - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. GNDA 97 - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. GNDPHY 41 I TTL GND of the Ethernet PHY GNDPHY 42 I TTL GND of Ethernet PHY GNDPHY 85 I TTL GND of the Ethernet PHY GNDPHY 86 I TTL GND of the Ethernet PHY HIB 51 O TTL An output that indicates the processor is in hibernate mode. I2C0SCL 70 I/O OD I2C module 0 clock I2C0SDA 71 I/O OD I2C module 0 data I2C1SCL 34 I/O OD I2C module 1 clock I2C1SDA 35 I/O OD I2C module 1 data June 14, 2007 501 Luminary Micro Confidential-Advance Product Information Signal Tables Pin Name Pin Number Pin Type LDO 7 - Buffer Type Description Power LED0 59 O TTL MII LED 0 LED1 60 O TTL MII LED 1 MDIO 58 I/O TTL MDIO of Ethernet PHY OSC0 48 I Analog Main oscillator crystal input or an external clock reference input. OSC1 49 O Analog Main oscillator crystal output. PA0 26 I/O TTL GPIO port A bit 0 PA1 27 I/O TTL GPIO port A bit 1 PA2 28 I/O TTL GPIO port A bit 2 PA3 29 I/O TTL GPIO port A bit 3 PA4 30 I/O TTL GPIO port A bit 4 PA5 31 I/O TTL GPIO port A bit 5 PA6 34 I/O TTL GPIO port A bit 6 PA7 35 I/O TTL GPIO port A bit 7 PB0 66 I/O TTL GPIO port B bit 0 PB1 67 I/O TTL GPIO port B bit 1 PB2 70 I/O TTL GPIO port B bit 2 PB3 71 I/O TTL GPIO port B bit 3 PB4 92 I/O TTL GPIO port B bit 4 PB5 91 I/O TTL GPIO port B bit 5 PB6 90 I/O TTL GPIO port B bit 6 PB7 89 I/O TTL GPIO port B bit 7 PC0 80 I/O TTL GPIO port C bit 0 PC1 79 I/O TTL GPIO port C bit 1 PC2 78 I/O TTL GPIO port C bit 2 PC3 77 I/O TTL GPIO port C bit 3 PC4 25 I/O TTL GPIO port C bit 4 PC5 24 I/O TTL GPIO port C bit 5 PC6 23 I/O TTL GPIO port C bit 6 PC7 22 I/O TTL GPIO port C bit 7 PD0 10 I/O TTL GPIO port D bit 0 PD1 11 I/O TTL GPIO port D bit 1 PD2 12 I/O TTL GPIO port D bit 2 PD3 13 I/O TTL GPIO port D bit 3 PE0 72 I/O TTL GPIO port E bit 0 PE1 73 I/O TTL GPIO port E bit 1 PE2 74 I/O TTL GPIO port E bit 2 PE3 75 I/O TTL GPIO port E bit 3 Low drop-out regulator output voltage. This pin requires an external capacitor between the pin and GND of 1 µF or greater. When the on-chip LDO is used to provide power to the logic, the LDO pin must also be connected to the VDD25 pins at the board level in addition to the decoupling capacitor(s). 502 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Pin Name Pin Number Pin Type PF0 47 I/O Buffer Type Description TTL GPIO port F bit 0 PF1 61 I/O TTL GPIO port F bit 1 PF2 60 I/O TTL GPIO port F bit 2 PF3 59 I/O TTL GPIO port F bit 3 PG0 19 I/O TTL GPIO port G bit 0 PG1 18 I/O TTL GPIO port G bit 1 RST 64 I TTL System reset input. RXIN 37 I Analog RXIN of the Ethernet PHY RXIP 40 I Analog RXIP of the Ethernet PHY SSI0Clk 28 I/O TTL SSI module 0 clock SSI0Fss 29 I/O TTL SSI module 0 frame SSI0Rx 30 I TTL SSI module 0 receive SSI0Tx 31 O TTL SSI module 0 transmit SWCLK 80 I TTL JTAG/SWD CLK SWDIO 79 I/O TTL JTAG TMS and SWDIO SWO 77 O TTL JTAG TDO and SWO TCK 80 I TTL JTAG/SWD CLK TDI 78 I TTL JTAG TDI TDO 77 O TTL JTAG TDO and SWO TMS 79 I/O TTL JTAG TMS and SWDIO TRST 89 I TTL JTAG TRSTn TXON 46 O Analog TXON of Ethernet PHY TXOP 43 O Analog TXOP of Ethernet PHY U0Rx 26 I TTL UART module 0 receive. When in IrDA mode, this signal has IrDA modulation. U0Tx 27 O TTL UART module 0 transmit. When in IrDA mode, this signal has IrDA modulation. U1Rx 12 I TTL UART module 1 receive. When in IrDA mode, this signal has IrDA modulation. U1Tx 13 O TTL UART module 1 transmit. When in IrDA mode, this signal has IrDA modulation. U2Rx 19 I TTL UART 2 Receive. When in IrDA mode, this signal has IrDA modulation. U2Tx 18 O TTL UART 2 Transmit. When in IrDA mode, this signal has IrDA modulation. VBAT 55 - Power VCCPHY 36 I TTL VCC of the Ethernet PHY VCCPHY 83 I TTL VCC of the Ethernet PHY VCCPHY 84 I TTL VCC of the Ethernet PHY VDD 8 - Power Positive supply for I/O and some logic. VDD 20 - Power Positive supply for I/O and some logic. VDD 32 - Power Positive supply for I/O and some logic. Power source for the Hibernation Module. It is normally connected to the positive terminal of a battery and serves as the battery backup/Hibernation Module power-source supply. June 14, 2007 503 Luminary Micro Confidential-Advance Product Information Signal Tables Pin Name Pin Number Pin Type VDD 44 - Buffer Type Description Power Positive supply for I/O and some logic. VDD 56 - Power Positive supply for I/O and some logic. VDD 68 - Power Positive supply for I/O and some logic. VDD 81 - Power Positive supply for I/O and some logic. VDD 93 - Power Positive supply for I/O and some logic. VDD25 14 - Power Positive supply for most of the logic function, including the processor core and most peripherals. VDD25 38 - Power Positive supply for most of the logic function, including the processor core and most peripherals. VDD25 62 - Power Positive supply for most of the logic function, including the processor core and most peripherals. VDD25 88 - Power Positive supply for most of the logic function, including the processor core and most peripherals. VDDA 3 - Power The positive supply (3.3 V) for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. VDDA 98 - Power The positive supply (3.3 V) for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. WAKE 50 I OD An external input that brings the processor out of hibernate mode when asserted. XOSC0 52 I Analog Hibernation Module oscillator crystal input or an external clock reference input. Note that this is either a 4.19-MHz crystal or a 32.768-kHz oscillator for the Hibernation Module RTC. See the CLKSEL bit in the HIBCTL register. XOSC1 53 O Analog Hibernation Module oscillator crystal output. XTALNPHY 17 I TTL XTALN of the Ethernet PHY XTALPPHY 16 O TTL XTALP of the Ethernet PHY Table 20-3. Signals by Function, Except for GPIO Function ADC Pin Name Pin Number Pin Type Buffer Type Description ADC0 1 I Analog Analog-to-digital converter input 0. ADC1 2 I Analog Analog-to-digital converter input 1. ADC2 5 I Analog Analog-to-digital converter input 2. ADC3 6 I Analog Analog-to-digital converter input 3. ADC4 100 I Analog Analog-to-digital converter input 4. ADC5 99 I Analog Analog-to-digital converter input 5. ADC6 96 I Analog Analog-to-digital converter input 6. ADC7 95 I Analog Analog-to-digital converter input 7. 504 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Function Analog Comparators Pin Name Pin Number Pin Type Buffer Type Description C0+ 90 I Analog Analog comparator 0 positive input C0- 92 I Analog Analog comparator 0 negative input C0o 90 O TTL C1+ 24 I Analog Analog comparator positive input C1- 91 I Analog Analog comparator 1 negative input C1o 24 O TTL C2+ 23 I Analog Analog comparator positive input C2- 22 I Analog Analog comparator 2 negative input Analog comparator 0 output Analog comparator 1 output C2o 23 O TTL Analog comparator 2 output Controller Area Network CAN0Rx 10 I TTL CAN module 0 receive CAN0Tx 11 O TTL CAN module 0 transmit Ethernet PHY GNDPHY 41 I TTL GND of the Ethernet PHY GNDPHY 42 I TTL GND of Ethernet PHY GNDPHY 85 I TTL GND of the Ethernet PHY GNDPHY 86 I TTL GND of the Ethernet PHY LED0 59 O TTL MII LED 0 LED1 60 O TTL MII LED 1 MDIO 58 I/O TTL MDIO of Ethernet PHY RXIN 37 I Analog RXIN of the Ethernet PHY RXIP 40 I Analog RXIP of the Ethernet PHY TXON 46 O Analog TXON of Ethernet PHY TXOP 43 O Analog TXOP of Ethernet PHY VCCPHY 36 I TTL VCC of the Ethernet PHY VCCPHY 83 I TTL VCC of the Ethernet PHY VCCPHY 84 I TTL VCC of the Ethernet PHY XTALNPHY 17 I TTL XTALN of the Ethernet PHY XTALPPHY 16 O TTL XTALP of the Ethernet PHY General-Purpose CCP0 Timers CCP1 66 I/O TTL Capture/Compare/PWM 0 75 I/O TTL Capture/Compare/PWM 1 CCP2 67 I/O TTL Capture/Compare/PWM 2 CCP3 72 I/O TTL Capture/Compare/PWM 3 CCP4 74 I/O TTL Capture/Compare/PWM 4 CCP5 25 I/O TTL Capture/Compare/PWM 5 I2C0SCL 70 I/O OD I2C module 0 clock I2C0SDA 71 I/O OD I2C module 0 data I2C1SCL 34 I/O OD I2C module 1 clock I2C1SDA 35 I/O OD I2C module 1 data I2C June 14, 2007 505 Luminary Micro Confidential-Advance Product Information Signal Tables Function Pin Name Pin Number Pin Type Buffer Type Description JTAG/SWD/SWO SWCLK 80 I TTL JTAG/SWD CLK SWDIO 79 I/O TTL JTAG TMS and SWDIO SWO 77 O TTL JTAG TDO and SWO TCK 80 I TTL JTAG/SWD CLK TDI 78 I TTL JTAG TDI TDO 77 O TTL JTAG TDO and SWO TMS 79 I/O TTL JTAG TMS and SWDIO 506 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Function Power Pin Name Pin Number Pin Type Buffer Type Description GND 9 - Power Ground reference for logic and I/O pins. GND 15 - Power Ground reference for logic and I/O pins. GND 21 - Power Ground reference for logic and I/O pins. GND 33 - Power Ground reference for logic and I/O pins. GND 39 - Power Ground reference for logic and I/O pins. GND 45 - Power Ground reference for logic and I/O pins. GND 54 - Power Ground reference for logic and I/O pins. GND 57 - Power Ground reference for logic and I/O pins. GND 63 - Power Ground reference for logic and I/O pins. GND 69 - Power Ground reference for logic and I/O pins. GND 82 - Power Ground reference for logic and I/O pins. GND 87 - Power Ground reference for logic and I/O pins. GND 94 - Power Ground reference for logic and I/O pins. GNDA 4 - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. GNDA 97 - Power The ground reference for the analog circuits (ADC, Analog Comparators, etc.). These are separated from GND to minimize the electrical noise contained on VDD from affecting the analog functions. HIB 51 O TTL LDO 7 - Power Low drop-out regulator output voltage. This pin requires an external capacitor between the pin and GND of 1 µF or greater. When the on-chip LDO is used to provide power to the logic, the LDO pin must also be connected to the VDD25 pins at the board level in addition to the decoupling capacitor(s). VBAT 55 - Power Power source for the Hibernation Module. It is normally connected to the positive terminal of a battery and serves as the battery backup/Hibernation Module power-source supply. VDD 8 - Power Positive supply for I/O and some logic. VDD 20 - Power Positive supply for I/O and some logic. VDD 32 - Power Positive supply for I/O and some logic. VDD 44 - Power Positive supply for I/O and some logic. VDD 56 - Power Positive supply for I/O and some logic. VDD 68 - Power Positive supply for I/O and some logic. VDD 81 - Power Positive supply for I/O and some logic. VDD 93 - Power Positive supply for I/O and some logic. VDD25 14 - Power Positive supply for most of the logic function, including the processor core and most peripherals. VDD25 38 - Power Positive supply for most of the logic function, including the processor core and most peripherals. VDD25 62 - Power Positive supply for most of the logic function, including the processor core and most peripherals. An output that indicates the processor is in hibernate mode. June 14, 2007 507 Luminary Micro Confidential-Advance Product Information Signal Tables Function Pin Number Pin Type Buffer Type Description VDD25 88 - Power Positive supply for most of the logic function, including the processor core and most peripherals. VDDA 3 - Power The positive supply (3.3 V) for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. VDDA 98 - Power The positive supply (3.3 V) for the analog circuits (ADC, Analog Comparators, etc.). These are separated from VDD to minimize the electrical noise contained on VDD from affecting the analog functions. WAKE 50 I OD An external input that brings the processor out of hibernate mode when asserted. SSI0Clk 28 I/O TTL SSI module 0 clock SSI0Fss 29 I/O TTL SSI module 0 frame SSI0Rx 30 I TTL SSI module 0 receive SSI0Tx 31 O TTL SSI module 0 transmit System Control & CMOD0 Clocks 65 I/O TTL CPU Mode bit 0. Input must be set to logic 0 (grounded); other encodings reserved. CMOD1 76 I/O TTL CPU Mode bit 1. Input must be set to logic 0 (grounded); other encodings reserved. OSC0 48 I Analog Main oscillator crystal input or an external clock reference input. OSC1 49 O Analog Main oscillator crystal output. RST 64 I TTL System reset input. TRST 89 I TTL JTAG TRSTn XOSC0 52 I Analog Hibernation Module oscillator crystal input or an external clock reference input. Note that this is either a 4.19-MHz crystal or a 32.768-kHz oscillator for the Hibernation Module RTC. See the CLKSEL bit in the HIBCTL register. XOSC1 53 O Analog Hibernation Module oscillator crystal output. U0Rx 26 I TTL UART module 0 receive. When in IrDA mode, this signal has IrDA modulation. U0Tx 27 O TTL UART module 0 transmit. When in IrDA mode, this signal has IrDA modulation. U1Rx 12 I TTL UART module 1 receive. When in IrDA mode, this signal has IrDA modulation. U1Tx 13 O TTL UART module 1 transmit. When in IrDA mode, this signal has IrDA modulation. U2Rx 19 I TTL UART 2 Receive. When in IrDA mode, this signal has IrDA modulation. U2Tx 18 O TTL UART 2 Transmit. When in IrDA mode, this signal has IrDA modulation. SSI UART Pin Name Table 20-4. GPIO Pins and Alternate Functions GPIO Pin Pin Number Multiplexed Function PA0 26 U0Rx 508 Multiplexed Function June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller GPIO Pin Pin Number Multiplexed Function PA1 27 U0Tx PA2 28 SSI0Clk PA3 29 SSI0Fss PA4 30 SSI0Rx PA5 31 SSI0Tx PA6 34 I2C1SCL PA7 35 I2C1SDA PB0 66 CCP0 PB1 67 CCP2 PB2 70 I2C0SCL PB3 71 I2C0SDA PB4 92 C0- PB5 91 C1- PB6 90 C0+ PB7 89 TRST PC0 80 TCK SWCLK PC1 79 TMS SWDIO PC2 78 TDI PC3 77 TDO PC4 25 CCP5 PC5 24 C1+ C1o PC6 23 C2+ C2o PC7 22 C2- PD0 10 CAN0Rx PD1 11 CAN0Tx PD2 12 U1Rx PD3 13 U1Tx PE0 72 CCP3 PE1 73 PE2 74 CCP4 PE3 75 CCP1 PF0 47 PF1 61 PF2 60 LED1 PF3 59 LED0 PG0 19 U2Rx PG1 18 U2Tx June 14, 2007 Multiplexed Function C0o SWO 509 Luminary Micro Confidential-Advance Product Information Operating Characteristics 21 Operating Characteristics Table 21-1. Temperature Characteristics Characteristic Symbol Value a Operating temperature range TA -40 to +85 Unit °C a. Maximum storage temperature is 150°C. Table 21-2. Thermal Characteristics Characteristic Symbol Value a Thermal resistance (junction to ambient) ΘJA b Average junction temperature TJ 55.3 TA + (PAVG • ΘJA) Unit °C/W °C a. Junction to ambient thermal resistance θJA numbers are determined by a package simulator. b. Power dissipation is a function of temperature. 510 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 22 Electrical Characteristics 22.1 DC Characteristics 22.1.1 Maximum Ratings The maximum ratings are the limits to which the device can be subjected without permanently damaging the device. Note: The device is not guaranteed to operate properly at the maximum ratings. Table 22-1. Maximum Ratings Characteristic Symbol a Value Unit Min Max I/O supply voltage (VDD) VDD 0 4 V Core supply voltage (VDD25) VDD25 0 4 V Analog supply voltage (VDDA) VDDA 0 4 V Battery supply voltage (VBAT) VBAT 0 4 V 0 4 V Ethernet PHY supply voltage (VCCPHY) VCCPHY Input voltage VIN Maximum current per output pins I -0.3 5.5 - 25 V mA a. Voltages are measured with respect to GND. Important: This device contains circuitry to protect the inputs against damage due to high-static voltages or electric fields; however, it is advised that normal precautions be taken to avoid application of any voltage higher than maximum-rated voltages to this high-impedance circuit. Reliability of operation is enhanced if unused inputs are connected to an appropriate logic voltage level (for example, either GND or VDD). 22.1.2 Recommended DC Operating Conditions Table 22-2. Recommended DC Operating Conditions Parameter Parameter Name Min Nom Max Unit I/O supply voltage 3.0 3.3 3.6 V VDD25 Core supply voltage 2.25 2.5 2.75 V VDDA Analog supply voltage 3.0 3.3 3.6 V VBAT Battery supply voltage 2.3 3.0 3.6 V VDD VCCPHY Ethernet PHY supply voltage 3.0 3.3 3.6 V VIH High-level input voltage 2.0 - 5.0 V VIL Low-level input voltage -0.3 - 1.3 V VSIH High-level input voltage for Schmitt trigger inputs 0.8 * VDD - VDD V VSIL Low-level input voltage for Schmitt trigger inputs 0 - 0.2 * VDD V VOH High-level output voltage 2.4 - - V VOL Low-level output voltage - - 0.4 V June 14, 2007 511 Luminary Micro Confidential-Advance Product Information Electrical Characteristics Parameter Parameter Name IOH IOL 22.1.3 Min Nom Max Unit 2-mA Drive 2.0 - - mA 4-mA Drive 4.0 - - mA 8-mA Drive 8.0 - - mA 2-mA Drive 2.0 - - mA 4-mA Drive 4.0 - - mA 8-mA Drive 8.0 - - mA High-level source current, VOH=2.4 V Low-level sink current, VOL=0.4 V On-Chip Low Drop-Out (LDO) Regulator Characteristics Table 22-3. LDO Regulator Characteristics Parameter Parameter Name VLDOOUT 22.1.4 Min Nom Max Unit Programmable internal (logic) power supply output value 2.25 2.5 2.75 V Output voltage accuracy - 2% - % tPON Power-on time - - 100 µs tON Time on - - 200 µs tOFF Time off - - 100 µs VSTEP Step programming incremental voltage - 50 - mV CLDO External filter capacitor size for internal power supply - 1 - µF Power Specifications The power measurements specified in the tables that follow are run on the core processor using SRAM with the following specifications (except as noted): ■ VDD = 3.3 V ■ VDD25 = 2.50 V ■ VBAT = 3.0 V ■ VDDA = 3.3 V ■ VDDPHY = 3.3 V ■ Temperature = 25°C ■ Clock Source (MOSC) =3.579545 MHz Crystal Oscillator ■ Main oscillator (MOSC) = enabled ■ Internal oscillator (IOSC) = disabled 512 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 22.1.5 Flash Memory Characteristics Table 22-4. Flash Memory Characteristics Parameter Parameter Name PECYC TRET Min Nom a Max Unit Number of guaranteed program/erase cycles before failure 10,000 100,000 - cycles Data retention at average operating temperature of 85˚C 10 - - years TPROG Word program time 20 - - µs TERASE Page erase time 20 - - ms TME Mass erase time 200 - - ms a. A program/erase cycle is defined as switching the bits from 1-> 0 -> 1. 22.2 AC Characteristics 22.2.1 Load Conditions Unless otherwise specified, the following conditions are true for all timing measurements. Timing measurements are for 4-mA drive strength. Figure 22-1. Load Conditions CL = 50 pF pin GND 22.2.2 Clocks Table 22-5. Phase Locked Loop (PLL) Characteristics Parameter Parameter Name fref_crystal fref_ext Min a Crystal reference Nom Max Unit 3.579545 - 8.192 MHz External clock reference 3.579545 - 8.192 MHz a b fpll PLL frequency - 400 - MHz TREADY PLL lock time - - 0.5 ms a. The exact value is determined by the crystal value programmed into the XTAL field of the Run-Mode Clock Configuration (RCC) register. b. PLL frequency is automatically calculated by the hardware based on the XTAL field of the RCC register. Table 22-6. Clock Characteristics Parameter Name Min Nom Max Unit fIOSC Parameter Internal 12 MHz oscillator frequency 8.4 12 15.6 MHz fIOSC30KHZ Internal 30 KHz oscillator frequency 21 30 39 KHz fXOSC Hibernation module oscillator frequency - 4.194304 - MHz fXOSC_XTAL Crystal reference for hibernation oscillator - 4.194304 - MHz fXOSC_EXT External clock reference for hibernation module - 32.768 - KHz June 14, 2007 513 Luminary Micro Confidential-Advance Product Information Electrical Characteristics Parameter Parameter Name fMOSC Main oscillator frequency tMOSC_per Main oscillator period fref_crystal_bypass Crystal reference using the main oscillator (PLL in BYPASS mode) a a Min Nom 1 - Max Unit 8 MHz 125 - 1000 ns 1 - 8 MHz fref_ext_bypass External clock reference (PLL in BYPASS mode) 0 - 50 MHz fsystem_clock System clock 0 - 50 MHz a. The ADC must be clocked from the PLL or directly from a 14-MHz to 18-MHz clock source to operate properly. Table 22-7. Crystal Characteristics Parameter Name Frequency Units 6 4 3.5 Frequency tolerance ±50 ±50 ±50 ±50 ppm Aging ±5 ±5 ±5 ±5 ppm/yr Oscillation mode 22.2.3 Value 8 MHz Parallel Parallel Parallel Parallel Temperature stability (0 - 85 °C) ±25 ±25 ±25 ±25 ppm Motional capacitance (typ) 27.8 37.0 55.6 63.5 pF Motional inductance (typ) 14.3 19.1 28.6 32.7 mH Equivalent series resistance (max) 120 160 200 220 Ω Shunt capacitance (max) 10 10 10 10 pF Load capacitance (typ) 16 16 16 16 pF Drive level (typ) 100 100 100 100 µW Temperature Sensor Table 22-8. Temperature Sensor Characteristics 22.2.4 Parameter Parameter Name Min Nom Max Unit V TSO Output voltage 0.3 - 2.7 t TSERR Output voltage temperature accuracy - - ±3.5 ˚C t TSNL Output temperature nonlinearity - - ±1 V ˚C Analog-to-Digital Converter Table 22-9. ADC Characteristics Parameter Parameter Name VADCIN Min Nom Max Unit Maximum single-ended, full-scale analog input voltage - - 3.0 V Minimum single-ended, full-scale analog input voltage - - Maximum differential, full-scale analog input voltage - - 1.5 V -1.5 V 0 V Minimum differential, full-scale analog input voltage - - CADCIN Equivalent input capacitance - 1 - pF N Resolution - 10 - bits fADC ADC internal clock frequency 14 16 18 MHz tADCCONV Conversion time - - 16 tADCcycles f ADCCONV Conversion rate a 875 1000 1125 k samples/s 514 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Parameter Parameter Name Min Nom Max Unit INL Integral nonlinearity - - ±1 LSB DNL Differential nonlinearity - - ±1 LSB OFF Offset - - ±1 LSB GAIN Gain - - ±1 LSB a. tADC= 1/fADC clock 22.2.5 Analog Comparator Table 22-10. Analog Comparator Characteristics Parameter Parameter Name Min Nom Max Unit VOS Input offset voltage - ±10 ±25 mV VCM Input common mode voltage range 0 - VDD-1.5 V CMRR Common mode rejection ratio 50 - - dB TRT Response time - - 1 µs TMC Comparator mode change to Output Valid - - 10 µs Table 22-11. Analog Comparator Voltage Reference Characteristics Parameter Parameter Name 22.2.6 Min Nom Max Unit RHR Resolution high range - VDD/32 - LSB - LSB RLR Resolution low range - VDD/24 AHR Absolute accuracy high range - - ±1/2 LSB ALR Absolute accuracy low range - - ±1/4 LSB 2 I C 2 Table 22-12. I C Characteristics Parameter No. Parameter Parameter Name a I1 Max Unit - system clocks Start condition hold time 36 - tLP Clock Low period 36 - - system clocks tSRT I2CSCL/I2CSDA rise time (VIL =0.5 V to V IH =2.4 V) - - (see note b) ns tDH Data hold time 2 - - system clocks tSFT I2CSCL/I2CSDA fall time (VIH =2.4 V to V IL =0.5 V) - 9 10 ns tHT Clock High time 24 - - system clocks a tDS Data setup time 18 - - system clocks a tSCSR Start condition setup time (for repeated start condition 36 only) - - system clocks a tSCS Stop condition setup time - - system clocks a b a c a I2 I3 I4 I5 I6 I7 I8 I9 tSCH Min Nom 24 2 a. Values depend on the value programmed into the TPR bit in the I C Master Timer Period (I2CMTPR) register; a TPR programmed for the maximum I2CSCL frequency (TPR=0x2) results in a minimum output timing as shown in the table 2 above. The I C interface is designed to scale the actual data transition time to move it to the middle of the I2CSCL Low period. The actual position is affected by the value programmed into the TPR; however, the numbers given in the above values are minimum values. b. Because I2CSCL and I2CSDA are open-drain-type outputs, which the controller can only actively drive Low, the time I2CSCL or I2CSDA takes to reach a high level depends on external signal capacitance and pull-up resistor values. c. Specified at a nominal 50 pF load. June 14, 2007 515 Luminary Micro Confidential-Advance Product Information Electrical Characteristics 2 Figure 22-2. I C Timing I2 I6 I5 I2CSCL I1 I4 I7 I8 I3 I9 I2CSDA 22.2.7 Ethernet Controller a Table 22-13. 100BASE-TX Transmitter Characteristics Parameter Name Min Nom Max Unit Peak output amplitude 950 - 1050 mVpk Output amplitude symmetry 0.98 - 1.02 mVpk Output overshoot - - 5 % Rise/Fall time 3 - 5 ns Rise/Fall time imbalance - - 500 ps Duty cycle distortion - - - ps Jitter - - 1.4 ns a. Measured at the line side of the transformer. a Table 22-14. 100BASE-TX Transmitter Characteristics (informative) Parameter Name Min Nom Max Unit Return loss 16 - - dB Open-circuit inductance 350 - - µs a. The specifications in this table are included for information only. They are mainly a function of the external transformer and termination resistors used for measurements. Table 22-15. 100BASE-TX Receiver Characteristics Parameter Name Min Nom Max Signal detect assertion threshold 600 700 Unit mVppd Signal detect de-assertion threshold 350 425 - mVppd Differential input resistance 20 - - kΩ Jitter tolerance (pk-pk) 4 - - ns -75 - +75 % Signal detect assertion time - - 1000 µs Signal detect de-assertion time - - 4 µs Baseline wander tracking a Table 22-16. 10BASE-T Transmitter Characteristics Parameter Name Min Nom Max Unit Peak differential output signal 2.2 - 2.8 V Harmonic content 27 - - dB - 100 - ns Link pulse width 516 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Parameter Name Min Nom Max Unit Start-of-idle pulse width - 300 - ns 350 a. The Manchester-encoded data pulses, the link pulse and the start-of-idle pulse are tested against the templates and using the procedures found in Clause 14 of IEEE 802.3. a Table 22-17. 10BASE-T Transmitter Characteristics (informative) Parameter Name Min Output return loss 15 - - dB 29-17log(f/10) - - dB Peak common-mode output voltage - - 50 mV Common-mode rejection - - 100 mV Common-mode rejection jitter - - Output impedance balance Nom Max Unit 1 ns a. The specifications in this table are included for information only. They are mainly a function of the external transformer and termination resistors used for measurements. Table 22-18. 10BASE-T Receiver Characteristics Parameter Name Min Nom Max DLL phase acquisition time Unit - 10 - BT Jitter tolerance (pk-pk) 30 - - ns Input squelched threshold 500 600 700 mVppd Input unsquelched threshold 275 350 425 mVppd Differential input resistance - Bit error ratio - Common-mode rejection 25 - kΩ 10 20 -10 - - - - V a Table 22-19. Isolation Transformers Name Value Turns ratio Condition 1 CT : 1 CT +/- 5% Open-circuit inductance 350 uH (min) @ 10 mV, 10 kHz Leakage inductance 0.40 uH (max) @ 1 MHz (min) Inter-winding capacitance 25 pF (max) DC resistance 0.9 Ohm (max) Insertion loss 0.4 dB (typ) 0-65 MHz 1500 Vrms HIPOT a. Two simple 1:1 isolation transformers are required at the line interface. Transformers with integrated common-mode chokes are recommended for exceeding FCC requirements. This table gives the recommended line transformer characteristics. Note: The 100Base-TX amplitude specifications assume a transformer loss of 0.4 dB. For the transmit line transformer with higher insertion losses, up to 1.2 dB of insertion loss can be compensated by selecting the appropriate setting in the Transmit Amplitude Selection (TXO) bits in the MR19 register. June 14, 2007 517 Luminary Micro Confidential-Advance Product Information Electrical Characteristics a Table 22-20. Ethernet Reference Crystal Name Frequency b Value Condition 25.00000 MHz c Load capacitance 4 pF Frequency tolerance ±50 PPM Aging ±2 PPM/yr Temperature stability (0° to 70°) ±5 PPM Oscillation mode Parallel resonance, fundamental mode Parameters at 25° C ±2° C; Drive level = 0.5 mW Drive level (typ) 50-100 µW Shunt capacitance (max) 10 pF Motional capacitance (min) 10 fF Serious resistance (max) 60 Ω Spurious response (max) > 5 dB below main within 500 kHz a. If the internal crystal oscillator is used, select a crystal with the following characteristics. b. Equivalent differential capacitance across XTLP/XTLN. c. If crystal with a larger load is used, external shunt capacitors to ground should be added to make up the equivalent capacitance difference. Figure 22-3. External XTLP Oscillator Characteristics Tr Tf Tclkhi Tclklo Tclkper Table 22-21. External XTLP Oscillator Characteristics Parameter Name Symbol Min Nom Max Unit XTLN Input Low Voltage XTLNILV a XTLP Frequency b XTLP Period XTLP Duty Cycle - - 0.8 - - 25.0 - - Tclkper - 40 - - XTLPDC 40 - 60 % XTLPf 40 Rise/Fall Time Absolute Jitter Tr , Tf 60 - - 4.0 ns - - 0.1 ns a. IEEE 802.3 frequency tolerance ±50 ppm. 518 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller b. IEEE 802.3 frequency tolerance ±50 ppm. 22.2.8 Hibernation Module The Hibernation Module requires special system implementation considerations since it is intended to power-down all other sections of its host device. The system power-supply distribution and interfaces of the system must be driven to 0 VDC or powered down with the same regulator controlled by HIB. The regulators controlled by HIB are expected to have a settling time of 250 μs or less. Table 22-22. Hibernation Module Characteristics Parameter No Parameter H1 tHIB_LOW Internal 32.768 KHz clock reference rising edge to /HIB asserted - 200 - μs H2 tHIB_HIGH Internal 32.768 KHz clock reference rising edge to /HIB deasserted - 30 - μs 62 - - μs 62 - 124 μs 20 - - ms tHIB_REG_WRITE Time for a write to non-volatile registers in HIB module to complete 92 - - μs H3 Min Nom Max Unit tWAKE_ASSERT /WAKE assertion time H4 tWAKETOHIB /WAKE assert to /HIB desassert a H5 H6 Parameter Name tXOSC_SETTLE XOSC settling time a. This parameter is highly sensitive to PCB layout and trace lengths, which may make this parameter time longer. Care must be taken in PCB design to minimize trace lengths and RLC (resistance, inductance, capacitance). Figure 22-4. Hibernation Module Timing 32.768 KHz (internal) H1 H2 /HIB H4 /WAKE H3 22.2.9 Synchronous Serial Interface (SSI) Table 22-23. SSI Characteristics Parameter No. Parameter Parameter Name Min Nom Max Unit S1 tclk_per SSIClk cycle time 2 - S2 tclk_high SSIClk high time - 1/2 65024 system clocks - t clk_per S3 tclk_low SSIClk low time - 1/2 - t clk_per S4 tclkrf SSIClk rise/fall time - 7.4 26 ns S5 tDMd Data from master valid delay time 0 - 20 ns S6 tDMs Data from master setup time 20 - - ns S7 tDMh Data from master hold time 40 - - ns S8 tDSs Data from slave setup time 20 - - ns June 14, 2007 519 Luminary Micro Confidential-Advance Product Information Electrical Characteristics Parameter No. Parameter Parameter Name S9 tDSh Min Nom Max Data from slave hold time 40 - Unit - ns Figure 22-5. SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing Measurement S1 S4 S2 SSIClk S3 SSIFss SSITx SSIRx MSB LSB 4 to 16 bits Figure 22-6. SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer S2 S1 SSIClk S3 SSIFss SSITx MSB LSB 8-bit control SSIRx 0 MSB LSB 4 to 16 bits output data 520 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Figure 22-7. SSI Timing for SPI Frame Format (FRF=00), with SPH=1 S1 S4 S2 SSIClk (SPO=0) S3 SSIClk (SPO=1) S6 SSITx (master) MSB S5 SSIRx (slave) S7 S8 LSB S9 MSB LSB SSIFss 22.2.10 JTAG and Boundary Scan Table 22-24. JTAG Characteristics Parameter No. Parameter Parameter Name J1 fTCK TCK operational clock frequency J2 tTCK TCK operational clock period J3 tTCK_LOW TCK clock Low time J4 tTCK_HIGH J5 tTCK_R J6 tTCK_F Min Nom Max Unit 0 - 100 - 10 MHz - ns - tTCK - ns TCK clock High time - tTCK - ns TCK rise time 0 - 10 ns TCK fall time 0 - 10 ns J7 tTMS_SU TMS setup time to TCK rise 20 - - ns J8 tTMS_HLD TMS hold time from TCK rise 20 - - ns J9 tTDI_SU TDI setup time to TCK rise 25 - - ns J10 tTDI_HLD TDI hold time from TCK rise 25 - - ns J11 TCK fall to Data Valid from High-Z - 23 35 ns 4-mA drive 15 26 ns 8-mA drive 14 25 ns 8-mA drive with slew rate control 18 29 ns t TDO_ZDV J12 t TDO_DV TCK fall to Data Valid from Data Valid 2-mA drive 2-mA drive 21 35 ns 4-mA drive 14 25 ns 8-mA drive 13 24 ns 8-mA drive with slew rate control 18 28 ns June 14, 2007 - 521 Luminary Micro Confidential-Advance Product Information Electrical Characteristics Parameter No. Parameter J13 TCK fall to High-Z from Data Valid Parameter Name 9 11 ns 4-mA drive 7 9 ns 8-mA drive 6 8 ns 8-mA drive with slew rate control 7 9 ns t TDO_DVZ J14 tTRST J15 tTRST_SU Min Nom Max Unit 2-mA drive - TRST assertion time 100 - - ns TRST setup time to TCK rise 10 - - ns Figure 22-8. JTAG Test Clock Input Timing J2 J3 J4 TCK J6 J5 Figure 22-9. JTAG Test Access Port (TAP) Timing TCK J7 TMS TDI J8 J7 TMS Input Valid TMS Input Valid J9 J9 J10 TDI Input Valid J11 TDO J8 J10 TDI Input Valid J12 J13 TDO Output Valid TDO Output Valid Figure 22-10. JTAG TRST Timing TCK J14 J15 TRST 22.2.11 General-Purpose I/O Note: All GPIOs are 5 V-tolerant. 522 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Table 22-25. GPIO Characteristics Parameter Parameter Name tGPIOR Condition GPIO Rise Time (from 20% to 80% of VDD) Min Nom Max Unit 2-mA drive - 4-mA drive tGPIOF 22.2.12 17 26 ns 9 13 ns 8-mA drive 6 9 ns 8-mA drive with slew rate control 10 12 ns GPIO Fall Time (from 80% to 20% of VDD) 2-mA drive 17 25 ns 4-mA drive - 8 12 ns 8-mA drive 6 10 ns 8-mA drive with slew rate control 11 13 ns Reset Table 22-26. Reset Characteristics Parameter No. Parameter Parameter Name R1 Min Nom Max Unit VTH Reset threshold R2 VBTH Brown-Out threshold R3 TPOR Power-On Reset timeout - 10 - ms R4 TBOR Brown-Out timeout - 500 - µs R5 TIRPOR Internal reset timeout after POR 6 - 11 ms R6 TIRBOR Internal reset timeout after BOR 0 - 1 µs R7 TIRHWR Internal reset timeout after hardware reset (RST pin) R8 TIRSWR Internal reset timeout after software-initiated system reset R9 TIRWDR R10 TVDDRISE R11 TMIN - 2.0 - 2.85 2.9 2.95 a V V 0 - 1 ms 2.5 - 20 µs 2.5 - 20 µs Supply voltage (VDD) rise time (0V-3.3V) - - 100 ms Minimum RST pulse width 2 - a a Internal reset timeout after watchdog reset - µs a. 20 * t MOSC_per Figure 22-11. External Reset Timing (RST) RST R11 R7 /Reset (Internal) June 14, 2007 523 Luminary Micro Confidential-Advance Product Information Electrical Characteristics Figure 22-12. Power-On Reset Timing R1 VDD R3 /POR (Internal) R5 /Reset (Internal) Figure 22-13. Brown-Out Reset Timing R2 VDD R4 /BOR (Internal) R6 /Reset (Internal) Figure 22-14. Software Reset Timing SW Reset R8 /Reset (Internal) Figure 22-15. Watchdog Reset Timing WDOG Reset (Internal) R9 /Reset (Internal) 524 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 23 Package Information Figure 23-1. 100-Pin LQFP Package Notes 1. All dimensions shown in mm. 2. Dimensions shown are nominal with tolerances indicated. 3. Foot length 'L' is measured at gage plane 0.25 mm above seating plane. 4. L/F: Eftec 64T Cu or equivalent, 0.127 mm (0.005") or 0.152 mm (0.006") thick. 5. Use variation BED for body dimensions. Body +2.00 mm Footprint, 1.4 mm package thickness Symbols Leads A Max. A1 100L 1.60 0.05 Min./0.15 Max. June 14, 2007 525 Luminary Micro Confidential-Advance Product Information Package Information A2 ±0.05 1.40 D ±0.20 16.00 D1 ±0.05 14.00 E ±0.20 16.00 E1 ±0.05 14.00 L ±0.15/-0.10 0.60 e BASIC 0.50 b ±0.05 0.22 θ 0˚~7˚ ddd Max. ccc Max. 0.08 0.08 JEDEC Reference Drawing MS-026 Variation Designator BED 526 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller 24 Ordering and Contact Information 24.1 Ordering Information LM3Snnnn–gppss–rrm Part Number Shipping Medium T = Tape-and-reel Omitted = Default shipping (tray or tube) Temperature I = -40 C to 85 C Revision Omitted = Default to current shipping revision A0 = First all-layer mask A1 = Metal layers update to A0 A2 = Metal layers update to A1 B0 = Second all-layer mask revision Package RN = 28-pin SOIC QN = 48-pin LQFP QC = 100-pin LQFP Speed 20 = 20 MHz 25 = 25 MHz 50 = 50 MHz Table 24-1. Part Ordering Information Orderable Part Number Description LM3S8938-IQC50 24.2 ® Stellaris LM3S8938 Microcontroller Company Information Luminary Micro, Inc. designs, markets, and sells ARM Cortex-M3-based microcontrollers (MCUs). Austin, Texas-based Luminary Micro is the lead partner for the Cortex-M3 processor, delivering the world's first silicon implementation of the Cortex-M3 processor. Luminary Micro's introduction of the Stellaris® family of products provides 32-bit performance for the same price as current 8- and 16-bit microcontroller designs. With entry-level pricing at $1.00 for an ARM technology-based MCU, Luminary Micro's Stellaris product line allows for standardization that eliminates future architectural upgrades or software tool changes. Luminary Micro, Inc. 108 Wild Basin, Suite 350 Austin, TX 78746 Main: +1-512-279-8800 Fax: +1-512-279-8879 http://www.luminarymicro.com [email protected] 24.3 Support Information For support on Luminary Micro products, contact: [email protected] +1-512-279-8800, ext. 3 June 14, 2007 527 Luminary Micro Confidential-Advance Product Information Serial Flash Loader A Serial Flash Loader A.1 Serial Flash Loader ® The Stellaris serial flash loader is a preprogrammed flash-resident utility used to download code to the flash memory of a device without the use of a debug interface. The serial flash loader uses a simple packet interface to provide synchronous communication with the device. The flash loader runs off the crystal and does not enable the PLL, so its speed is determined by the crystal used. The two serial interfaces that can be used are the UART0 and SSI interfaces. For simplicity, both the data format and communication protocol are identical for both serial interfaces. A.2 Interfaces Once communication with the flash loader is established via one of the serial interfaces, that interface is used until the flash loader is reset or new code takes over. For example, once you start communicating using the SSI port, communications with the flash loader via the UART are disabled until the device is reset. A.2.1 UART The Universal Asynchronous Receivers/Transmitters (UART) communication uses a fixed serial format of 8 bits of data, no parity, and 1 stop bit. The baud rate used for communication is automatically detected by the flash loader and can be any valid baud rate supported by the host and the device. The auto detection sequence requires that the baud rate should be no more than 1/32 the crystal frequency of the board that is running the serial flash loader. This is actually the ® same as the hardware limitation for the maximum baud rate for any UART on a Stellaris device. In order to determine the baud rate, the serial flash loader needs to determine the relationship between its own crystal frequency and the baud rate. This is enough information for the flash loader to configure its UART to the same baud rate as the host. This automatic baud-rate detection allows the host to use any valid baud rate that it wants to communicate with the device. The method used to perform this automatic synchronization relies on the host sending the flash loader two bytes that are both 0x55. This generates a series of pulses to the flash loader that it can use to calculate the ratios needed to program the UART to match the host’s baud rate. After the host sends the pattern, it attempts to read back one byte of data from the UART. The flash loader returns the value of 0xCC to indicate successful detection of the baud rate. If this byte is not received after at least twice the time required to transfer the two bytes, the host can resend another pattern of 0x55, 0x55, and wait for the 0xCC byte again until the flash loader acknowledges that it has received a synchronization pattern correctly. For example, the time to wait for data back from the flash loader should be calculated as at least 2*(20(bits/sync)/baud rate (bits/sec)). For a baud rate of 115200, this time is 2*(20/115200) or 0.35 ms. A.2.2 SSI The Synchronous Serial Interface (SSI) port also uses a fixed serial format for communications, with the framing defined as Motorola format with SPH set to 1 and SPO set to 1. See the section on SSI formats for more details on this transfer protocol. Like the UART, this interface has hardware requirements that limit the maximum speed that the SSI clock can run. This allows the SSI clock to be at most 1/12 the crystal frequency of the board running the flash loader. Since the host device is the master, the SSI on the flash loader device does not need to determine the clock as it is provided directly by the host. 528 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller A.3 Packet Handling All communications, with the exception of the UART auto-baud, are done via defined packets that are acknowledged (ACK) or not acknowledged (NAK) by the devices. The packets use the same format for receiving and sending packets, including the method used to acknowledge successful or unsuccessful reception of a packet. A.3.1 Packet Format All packets sent and received from the device use the following byte-packed format. struct { unsigned char ucSize; unsigned char ucCheckSum; unsigned char Data[]; }; A.3.2 ucSize The first byte received holds the total size of the transfer including the size and checksum bytes. ucChecksum This holds a simple checksum of the bytes in the data buffer only. The algorithm is Data[0]+Data[1]+…+ Data[ucSize-3]. Data This is the raw data intended for the device, which is formatted in some form of command interface. There should be ucSize–2 bytes of data provided in this buffer to or from the device. Sending Packets The actual bytes of the packet can be sent individually or all at once; the only limitation is that commands that cause flash memory access should limit the download sizes to prevent losing bytes during flash programming. This limitation is discussed further in the commands that interact with the flash. Once the packet has been formatted correctly by the host, it should be sent out over the UART or SSI interface. Then the host should poll the UART or SSI interface for the first non-zero data returned from the device. The first non-zero byte will either be an ACK (0xCC) or a NAK (0x33) byte from the device indicating the packet was received successfully (ACK) or unsuccessfully (NAK). This does not indicate that the actual contents of the command issued in the data portion of the packet were valid, just that the packet was received correctly. A.3.3 Receiving Packets The flash loader sends a packet of data in the same format that it receives a packet. The flash loader may transfer leading zero data before the first actual byte of data is sent out. The first non-zero byte is the size of the packet followed by a checksum byte, and finally followed by the data itself. There is no break in the data after the first non-zero byte is sent from the flash loader. Once the device communicating with the flash loader receives all the bytes, it must either ACK or NAK the packet to indicate that the transmission was successful. The appropriate response after sending a NAK to the flash loader is to resend the command that failed and request the data again. If needed, the host may send leading zeros before sending down the ACK/NAK signal to the flash loader, as the flash loader only accepts the first non-zero data as a valid response. This zero padding is needed by the SSI interface in order to receive data to or from the flash loader. June 14, 2007 529 Luminary Micro Confidential-Advance Product Information Serial Flash Loader A.4 Commands The next section defines the list of commands that can be sent to the flash loader. The first byte of the data should always be one of the defined commands, followed by data or parameters as determined by the command that is sent. A.4.1 COMMAND_PING (0X20) This command simply accepts the command and sets the global status to success. The format of the packet is as follows: Byte[0] = 0x03; Byte[1] = checksum(Byte[2]); Byte[2] = COMMAND_PING; The ping command has 3 bytes and the value for COMMAND_PING is 0x20 and the checksum of one byte is that same byte, making Byte[1] also 0x20. Since the ping command has no real return status, the receipt of an ACK can be interpreted as a successful ping to the flash loader. A.4.2 COMMAND_GET_STATUS (0x23) This command returns the status of the last command that was issued. Typically, this command should be sent after every command to ensure that the previous command was successful or to properly respond to a failure. The command requires one byte in the data of the packet and should be followed by reading a packet with one byte of data that contains a status code. The last step is to ACK or NAK the received data so the flash loader knows that the data has been read. Byte[0] = 0x03 Byte[1] = checksum(Byte[2]) Byte[2] = COMMAND_GET_STATUS A.4.3 COMMAND_DOWNLOAD (0x21) This command is sent to the flash loader to indicate where to store data and how many bytes will be sent by the COMMAND_SEND_DATA commands that follow. The command consists of two 32-bit values that are both transferred MSB first. The first 32-bit value is the address to start programming data into, while the second is the 32-bit size of the data that will be sent. This command also triggers an erase of the full area to be programmed so this command takes longer than other commands. This results in a longer time to receive the ACK/NAK back from the board. This command should be followed by a COMMAND_GET_STATUS to ensure that the Program Address and Program size are valid for the device running the flash loader. The format of the packet to send this command is a follows: Byte[0] = 11 Byte[1] = checksum(Bytes[2:10]) Byte[2] = COMMAND_DOWNLOAD Byte[3] = Program Address [31:24] Byte[4] = Program Address [23:16] Byte[5] = Program Address [15:8] Byte[6] = Program Address [7:0] Byte[7] = Program Size [31:24] Byte[8] = Program Size [23:16] Byte[9] = Program Size [15:8] Byte[10] = Program Size [7:0] 530 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller A.4.4 COMMAND_SEND_DATA (0x24) This command should only follow a COMMAND_DOWNLOAD command or another COMMAND_SEND_DATA command if more data is needed. Consecutive send data commands automatically increment address and continue programming from the previous location. The caller should limit transfers of data to a maximum 8 bytes of packet data to allow the flash to program successfully and not overflow input buffers of the serial interfaces. The command terminates programming once the number of bytes indicated by the COMMAND_DOWNLOAD command has been received. Each time this function is called it should be followed by a COMMAND_GET_STATUS to ensure that the data was successfully programmed into the flash. If the flash loader sends a NAK to this command, the flash loader does not increment the current address to allow retransmission of the previous data. Byte[0] = 11 Byte[1] = checksum(Bytes[2:10]) Byte[2] = COMMAND_SEND_DATA Byte[3] = Data[0] Byte[4] = Data[1] Byte[5] = Data[2] Byte[6] = Data[3] Byte[7] = Data[4] Byte[8] = Data[5] Byte[9] = Data[6] Byte[10] = Data[7] A.4.5 COMMAND_RUN (0x22) This command is used to tell the flash loader to execute from the address passed as the parameter in this command. This command consists of a single 32-bit value that is interpreted as the address to execute. The 32-bit value is transmitted MSB first and the flash loader responds with an ACK signal back to the host device before actually executing the code at the given address. This allows the host to know that the command was received successfully and the code is now running. Byte[0] Byte[1] Byte[2] Byte[3] Byte[4] Byte[5] Byte[6] A.4.6 = = = = = = = 7 checksum(Bytes[2:6]) COMMAND_RUN Execute Address[31:24] Execute Address[23:16] Execute Address[15:8] Execute Address[7:0] COMMAND_RESET (0x25) This command is used to tell the flash loader device to reset. This is useful when downloading a new image that overwrote the flash loader and wants to start from a full reset. Unlike the COMMAND_RUN command, this allows the initial stack pointer to be read by the hardware and set up for the new code. It can also be used to reset the flash loader if a critical error occurs and the host device wants to restart communication with the flash loader. Byte[0] = 3 Byte[1] = checksum(Byte[2]) Byte[2] = COMMAND_RESET June 14, 2007 531 Luminary Micro Confidential-Advance Product Information Serial Flash Loader The flash loader responds with an ACK signal back to the host device before actually executing the software reset to the device running the flash loader. This allows the host to know that the command was received successfully and the part will be reset. 532 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller B Name Register Quick Reference 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 Offset System Control Base: 0x400F.E000 VER DID0 CLASS 0x000 RO MAJOR MINOR PBORCTL 0x030 R/W BORIOR LDOPCTL 0x034 R/W VADJ RIS 0x050 RO PLLLRIS BORRIS PLLLIM BORIM PLLLMIS BORMIS IMC 0x054 R/W MISC 0x058 R/W1C RESC 0x05C R/W LDO ACG RCC SYSDIV SW WDT BOR POR EXT USESYSDIV 0x060 R/W PWRDN BYPASS XTAL OSCSRC IOSCDIS MOSCDIS PLLCFG 0x064 RO OD F USERCC2 RCC2 R SYSDIV2 0x070 R/W PWRDN2 BYPASS2 OSCSRC2 DSDIVORIDE DSLPCLKCFG 0x144 R/W DSOSCSRC VER DID1 FAM PARTNO 0x004 RO PINCOUNT TEMP PKG ROHS QUAL SRAMSZ DC0 0x008 RO FLASHSZ CAN0 DC1 SARADC0 0x010 RO SYSDIV MAXADCSPD MPU HIB TEMPSNS PLL COMP2 COMP1 COMP0 DC2 WDT SWO SWD JTAG TIMER3 TIMER2 TIMER1 TIMER0 0x014 RO I2C1 I2C0 CCP5 DC3 CCP4 SSI0 CCP3 CCP2 CCP1 CCP0 ADC7 ADC6 ADC5 ADC4 ADC3 UART2 UART1 UART0 ADC2 ADC1 ADC0 0x018 RO DC4 C2O 0x01C EPHY0 C2PLUS C2MINUS EMAC0 C1O C1PLUS C1MINUS C0O C0PLUS C0MINUS E1588 June 14, 2007 533 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 GPIOG GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA Offset RO CAN0 RCGC0 SARADC0 0x100 R/W MAXADCSPD HIB WDT CAN0 SCGC0 SARADC0 0x110 R/W MAXADCSPD HIB WDT CAN0 DCGC0 SARADC0 0x120 R/W MAXADCSPD HIB WDT COMP2 COMP1 COMP0 RCGC1 TIMER3 TIMER2 TIMER1 TIMER0 0x104 R/W I2C1 I2C0 SSI0 COMP2 COMP1 COMP0 SCGC1 UART2 UART1 UART0 TIMER3 TIMER2 TIMER1 TIMER0 0x114 R/W I2C1 I2C0 SSI0 COMP2 COMP1 COMP0 DCGC1 UART2 UART1 UART0 TIMER3 TIMER2 TIMER1 TIMER0 0x124 R/W RCGC2 I2C1 I2C0 EPHY0 EMAC0 SSI0 UART2 UART1 UART0 0x108 R/W EPHY0 SCGC2 GPIOG GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA GPIOG GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA GPIOG GPIOF GPIOE GPIOD GPIOC GPIOB GPIOA EMAC0 0x118 R/W EPHY0 DCGC2 EMAC0 0x128 R/W CAN0 SRCR0 SARADC0 0x040 R/W HIB WDT COMP2 COMP1 COMP0 SRCR1 TIMER3 TIMER2 TIMER1 TIMER0 0x044 R/W SRCR2 I2C1 I2C0 EPHY0 EMAC0 SSI0 UART2 UART1 UART0 GPIOC GPIOB GPIOA 0x048 R/W GPIOG GPIOF GPIOE GPIOD Hibernation Module RTCC HIBRTCC 0x000 RO RTCC RTCM0 HIBRTCM0 0x004 R/W RTCM0 RTCM1 HIBRTCM1 0x008 R/W RTCM1 RTCLD HIBRTCLD 0x00C R/W RTCLD HIBCTL 0x010 R/W HIBIM VABORT CLK32EN LOWBATEN PINWEN RTCWEN CLKSEL HIBREQ RTCEN 0x014 534 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Name 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 Offset R/W EXTW LOWBAT RTCALT1 RTCALT0 EXTW LOWBAT RTCALT1 RTCALT0 EXTW LOWBAT RTCALT1 RTCALT0 EXTW LOWBAT RTCALT1 RTCALT0 COMT MERASE ERASE HIBRIS 0x018 RO HIBMIS 0x01C RO HIBIC 0x020 W1C HIBRTCT 0x024 R/W TRIM HIBDATA 0x030- RTD R/W RTD 0x12C Internal Memory Base: 0x400F.D000 Base: 0x400F.E000 OFFSET FMA 0x000 R/W OFFSET DATA FMD 0x004 R/W DATA WRKEY FMC 0x008 R/W WRITE FCRIS 0x00C RO PRIS ARIS FCIM 0x010 R/W PMASK AMASK FCMISC 0x014 R/W1C PMISC AMISC DBG1 DBG0 USECRL 0x140 R/W USEC 0x130 READ_ENABLE FMPRE0 and R/W READ_ENABLE 0x200 0x134 PROG_ENABLE FMPPE0 and R/W PROG_ENABLE 0x400 NOTWRT ITEN USER_DBG DATA 0x1D0 R/W DATA NOTWRT ITEN USER_REG0 INIT1 DATA 0x1E0 R/W DATA June 14, 2007 535 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 Offset NOTWRT ITEN USER_REG1 DATA 0x1E4 R/W DATA READ_ENABLE FMPRE1 0x204 R/W READ_ENABLE READ_ENABLE FMPRE2 0x208 R/W READ_ENABLE READ_ENABLE FMPRE3 0x20C R/W READ_ENABLE PROG_ENABLE FMPPE1 0x404 R/W PROG_ENABLE PROG_ENABLE FMPPE2 0x408 R/W PROG_ENABLE PROG_ENABLE FMPPE3 0x40C R/W PROG_ENABLE General-Purpose Input/Outputs (GPIOs) Base: 0x4000.4000 Base: 0x4000.5000 Base: 0x4000.6000 Base: 0x4000.7000 Base: 0x4002.4000 Base: 0x4002.5000 Base: 0x4002.6000 GPIODATA 0x000 R/W DATA GPIODIR 0x400 R/W DIR GPIOIS 0x404 R/W IS GPIOIBE 0x408 R/W IBE GPIOIEV 0x40C R/W IEV GPIOIM 0x410 R/W IME GPIORIS 0x414 RO RIS GPIOMIS 0x418 RO GPIOICR MIS 0x41C 536 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Name 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 Offset W1C IC GPIOAFSEL 0x420 R/W AFSEL GPIODR2R 0x500 R/W DRV2 GPIODR4R 0x504 R/W DRV4 GPIODR8R 0x508 R/W DRV8 GPIOODR 0x50C R/W ODE GPIOPUR 0x510 R/W PUE GPIOPDR 0x514 R/W PDE GPIOSLR 0x518 R/W SRL GPIODEN 0x51C R/W DEN LOCK GPIOLOCK 0x520 R/W LOCK GPIOCR 0x524 - CR GPIOPeriphID4 0xFD0 RO PID4 GPIOPeriphID5 0xFD4 RO PID5 GPIOPeriphID6 0xFD8 RO PID6 GPIOPeriphID7 0xFDC RO PID7 GPIOPeriphID0 0xFE0 RO PID0 GPIOPeriphID1 0xFE4 RO PID1 GPIOPeriphID2 0xFE8 RO PID2 June 14, 2007 537 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 Offset GPIOPeriphID3 0xFEC RO PID3 GPIOPCellID0 0xFF0 RO CID0 GPIOPCellID1 0xFF4 RO CID1 GPIOPCellID2 0xFF8 RO CID2 GPIOPCellID3 0xFFC RO CID3 General-Purpose Timers Base: 0x4003.0000 Base: 0x4003.1000 Base: 0x4003.2000 Base: 0x4003.3000 GPTMCFG 0x000 R/W GPTMCFG GPTMTAMR 0x004 R/W TAAMS TACMR TAMR TBAMS TBCMR TBMR GPTMTBMR 0x008 R/W GPTMCTL 0x00C R/W TBPWML TBOTE TBEVENT TBSTALL TBEN TAPWML TAOTE RTCEN TAEVENT TASTALL TAEN GPTMIMR 0x018 R/W CBEIM CBMIM TBTOIM RTCIM CAEIM CAMIM TATOIM GPTMRIS 0x01C RO CBERIS CBMRIS TBTORIS RTCRIS CAERIS CAMRIS TATORIS CBEMIS CBMMIS TBTOMIS RTCMIS CAEMIS CAMMIS TATOMIS CBECINT CBMCINT TBTOCINT RTCCINT CAECINT CAMCINT TATOCINT GPTMMIS 0x020 RO GPTMICR 0x024 W1C TAILRH GPTMTAILR 0x028 R/W TAILRL GPTMTBILR 0x02C R/W TBILRL TAMRH GPTMTAMATCHR 0x030 R/W TAMRL GPTMTBMATCHR 0x034 538 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Name 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 RESEN INTEN Offset R/W TBMRL GPTMTAPR 0x038 R/W TAPSR GPTMTBPR 0x03C R/W TBPSR GPTMTAPMR 0x040 R/W TAPSMR GPTMTBPMR 0x044 R/W TBPSMR TARH GPTMTAR 0x048 RO TARL GPTMTBR 0x04C RO TBRL Watchdog Timer Base: 0x4000.0000 WDTLoad WDTLOAD 0x000 R/W WDTLoad WDTValue WDTVALUE 0x004 RO WDTValue WDTCTL 0x008 R/W WDTIntClr WDTICR 0x00C WO WDTIntClr WDTRIS 0x010 RO WDTRIS WDTMIS 0x014 RO WDTMIS WDTTEST 0x418 R/W STALL WDTLock WDTLOCK 0xC00 R/W WDTLock WDTPeriphID4 0xFD0 RO PID4 WDTPeriphID5 0xFD4 RO PID5 WDTPeriphID6 0xFD8 RO PID6 June 14, 2007 539 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 ASEN3 ASEN2 ASEN1 ASEN0 INR3 INR2 INR1 INR0 MASK3 MASK2 MASK1 MASK0 IN3 IN2 IN1 IN0 OV3 OV2 OV1 OV0 UV1 UV0 Offset WDTPeriphID7 0xFDC RO PID7 WDTPeriphID0 0xFE0 RO PID0 WDTPeriphID1 0xFE4 RO PID1 WDTPeriphID2 0xFE8 RO PID2 WDTPeriphID3 0xFEC RO PID3 WDTPCellID0 0xFF0 RO CID0 WDTPCellID1 0xFF4 RO CID1 WDTPCellID2 0xFF8 RO CID2 WDTPCellID3 0xFFC RO CID3 Analog-to-Digital Converter (ADC) Base: 0x4003.8000 ADCACTSS 0x000 R/W ADCRIS 0x004 RO ADCIM 0x008 R/W ADCISC 0x00C R/W1C ADCOSTAT 0x010 R/W1C ADCEMUX 0x014 R/W EM3 EM2 EM1 EM0 ADCUSTAT 0x018 R/W1C UV3 UV2 ADCSSPRI 0x020 R/W SS3 SS2 SS1 SS0 ADCPSSI 0x028 540 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Name 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 SS3 SS2 SS1 SS0 Offset WO ADCSAC 0x030 R/W AVG ADCSSMUX0 MUX7 MUX6 MUX5 MUX4 MUX3 MUX2 MUX1 MUX0 0x040 R/W ADCSSCTL0 TS7 IE7 END7 D7 TS6 IE6 END6 D6 TS5 IE5 END5 D5 TS4 IE4 END4 D4 TS3 IE3 END3 D3 TS2 IE2 END2 D2 TS1 IE1 END1 D1 TS0 IE0 END0 D0 0x044 R/W ADCSSFIFO0 0x048 RO DATA ADCSSFIFO1 0x068 RO DATA ADCSSFIFO2 0x088 RO DATA ADCSSFSTAT0 0x04C RO FULL EMPTY HPTR TPTR FULL EMPTY HPTR TPTR FULL EMPTY HPTR TPTR ADCSSFSTAT1 0x06C RO ADCSSFSTAT2 0x08C RO ADCSSMUX1 0x060 R/W MUX3 MUX2 MUX1 MUX0 ADCSSCTL1 0x064 R/W TS3 IE3 END3 D3 TS2 IE2 END2 D2 TS1 IE1 END1 D1 TS0 IE0 END0 D0 ADCSSMUX2 0x080 R/W MUX3 MUX2 MUX1 MUX0 ADCSSCTL2 0x084 R/W TS3 IE3 END3 D3 TS2 IE2 END2 D2 TS1 IE1 END1 D1 TS0 IE0 END0 D0 ADCSSMUX3 0x0A0 R/W MUX0 ADCSSCTL3 0x0A4 R/W TS0 IE0 END0 D0 ADCSSFIFO3 0x0A8 RO ADCSSFSTAT3 0x0AC RO ADCTMLB 0x100 R/W CNT CONT DIFF June 14, 2007 TS MUX 541 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 Offset ADCTMLB 0x100 R/W LB Universal Asynchronous Receivers/Transmitters (UARTs) Base: 0x4000.C000 Base: 0x4000.D000 Base: 0x4000.E000 UARTDR 0x000 RO OE BE PE FE DATA UARTRSR/ UARTECR 0x004 OE R/W BE PE FE EPS PEN BRK SIRLP SIREN UARTEN UARTRSR/ UARTECR 0x004 DATA R/W UARTFR 0x018 RO TXFE RXFF TXFF RXFE BUSY UARTILPR 0x020 R/W ILPDVSR UARTIBRD 0x024 R/W DIVINT UARTFBRD 0x028 R/W DIVFRAC UARTLCRH 0x02C R/W SPS WLEN FEN STP2 UARTCTL 0x030 R/W RXE TXE LBE UARTIFLS 0x034 R/W RXIFLSEL TXIFLSEL UARTIM 0x038 R/W OEIM BEIM PEIM FEIM RTIM TXIM RXIM OERIS BERIS PERIS FERIS RTRIS TXRIS RXRIS OEMIS BEMIS PEMIS FEMIS RTMIS TXMIS RXMIS OEIC BEIC PEIC FEIC RTIC TXIC RXIC UARTRIS 0x03C RO UARTMIS 0x040 RO UARTICR 0x044 W1C UARTPeriphID4 0xFD0 RO PID4 UARTPeriphID5 0xFD4 542 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Name 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 Offset RO PID5 UARTPeriphID6 0xFD8 RO PID6 UARTPeriphID7 0xFDC RO PID7 UARTPeriphID0 0xFE0 RO PID0 UARTPeriphID1 0xFE4 RO PID1 UARTPeriphID2 0xFE8 RO PID2 UARTPeriphID3 0xFEC RO PID3 UARTPCellID0 0xFF0 RO CID0 UARTPCellID1 0xFF4 RO CID1 UARTPCellID2 0xFF8 RO CID2 UARTPCellID3 0xFFC RO CID3 Synchronous Serial Interface (SSI) Base: 0x4000.8000 SSICR0 0x000 R/W SCR SPH SPO FRF DSS SSICR1 0x004 R/W SOD MS SSE LBM RFF RNE TNF TFE TXIM RXIM RTIM RORIM TXRIS RXRIS RTRIS RORRIS SSIDR 0x008 R/W DATA SSISR 0x00C RO BSY SSICPSR 0x010 R/W CPSDVSR SSIIM 0x014 R/W SSIRIS 0x018 RO June 14, 2007 543 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 TXMIS RXMIS RTMIS RORMIS RTIC RORIC Offset SSIMIS 0x01C RO SSIICR 0x020 W1C SSIPeriphID4 0xFD0 RO PID4 SSIPeriphID5 0xFD4 RO PID5 SSIPeriphID6 0xFD8 RO PID6 SSIPeriphID7 0xFDC RO PID7 SSIPeriphID0 0xFE0 RO PID0 SSIPeriphID1 0xFE4 RO PID1 SSIPeriphID2 0xFE8 RO PID2 SSIPeriphID3 0xFEC RO PID3 SSIPCellID0 0xFF0 RO CID0 SSIPCellID1 0xFF4 RO CID1 SSIPCellID2 0xFF8 RO CID2 SSIPCellID3 0xFFC RO CID3 2 Inter-Integrated Circuit (I C) Interface Base: 0x4002.0000 Base: 0x4002.0800 Base: 0x4002.1000 Base: 0x4001.1800 I2CMSA 0x000 R/W SA R/S I2CMCS 0x004 R/W I2CMCS BUSBSY IDLE ARBLST DATACK ADRACK ERROR BUSY 0x004 544 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Name 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 ACK STOP START RUN Offset R/W I2CMDR 0x008 R/W DATA I2CMTPR 0x00C R/W TPR I2CMIMR 0x010 R/W IM I2CMRIS 0x014 RO RIS I2CMMIS 0x018 RO MIS I2CMICR 0x01C WO IC I2CMCR 0x020 R/W SFE MFE LPBK I2CSOAR 0x000 R/W OAR I2CSCSR 0x004 RO FBR TREQ RREQ I2CSCSR 0x004 RO DA I2CSDR 0x008 R/W DATA I2CSIMR 0x00C R/W IM I2CSRIS 0x010 RO RIS I2CSMIS 0x014 RO MIS I2CSICR 0x018 WO IC Controller Area Network (CAN) Module Base: 0x4004.0000 CANCTL 0x000 R/W Test CCE DAR BOff EWarn EPass EIE SIE IE INIT CANSTS 0x004 R/W RxOK June 14, 2007 TxOK LEC 545 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 Offset CANERR 0x008 RO RP REC TEC CANBIT 0x00C R/W TSeg2 TSeg1 SJW BRP CANINT 0x010 RO IntId CANTST 0x014 R/W Rx Tx LBack Silent Basic CANBRPE 0x018 R/W BRPE CANIF1CRQ 0x020 R/W Busy MNUM Busy MNUM CANIF2CRQ 0x080 R/W CANIF1CMSK 0x024 R/W WRNRD Mask Arb Control ClrIntPnd TxRqst/NewDat DataA DataB WRNRD Mask Arb Control ClrIntPnd TxRqst/NewDat DataA DataB CANIF2CMSK 0x084 R/W CANIF1MSK1 0x028 R/W Msk CANIF2MSK1 0x088 R/W Msk CANIF1MSK2 0x02C R/W MXtd MDir Msk MXtd MDir Msk CANIF2MSK2 0x08C R/W CANIF1ARB1 0x030 R/W ID CANIF2ARB1 0x090 R/W ID CANIF1ARB2 0x034 R/W MsgVal Xtd Dir ID MsgVal Xtd Dir ID NewDat MsgLst IntPnd CANIF2ARB2 0x094 R/W CANIF1MCTL 0x038 R/W UMask TxIE RxIE RmtEn TxRqst EoB DLC CANIF2MCTL 0x098 546 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Name 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 NewDat MsgLst IntPnd UMask TxIE RxIE RmtEn TxRqst EoB TXER RXINT Offset R/W DLC CANIF1DA1 0x03C R/W Data CANIF2DA1 0x09C R/W Data CANIF1DA2 0x040 R/W Data CANIF2DA2 0x0A0 R/W Data CANIF1DB1 0x044 R/W Data CANIF2DB1 0x0A4 R/W Data CANIF1DB2 0x048 R/W Data CANIF2DB2 0x0A8 R/W Data CANTXRQ1 0x100 RO TxRqst CANTXRQ2 0x104 RO TxRqst CANNWDA1 0x120 RO NewDat CANNWDA2 0x124 RO NewDat CANMSG1INT 0x140 RO IntPnd CANMSG2INT 0x144 RO IntPnd CANMSG1VAL 0x160 RO MsgVal CANMSG2VAL 0x164 RO MsgVal Ethernet Controller Base: 0x4004.8000 MACRIS 0x000 RO PHYINT MDINT RXER June 14, 2007 FOV TXEMP 547 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 MDINT RXER FOV TXEMP TXER RXINT Offset MACIACK 0x000 W1C MACIM 0x004 R/W PHYINTM MDINTM RXERM FOVM TXEMPM TXERM RXINTM MACRCTL 0x008 R/W RSTFIFO BADCRC PRMS AMUL RXEN CRC PADEN TXEN WRITE START MACTCTL 0x00C R/W DUPLEX RXDATA MACDATA 0x010 R/W RXDATA TXDATA MACDATA 0x010 R/W TXDATA MACIA0 MACOCT4 MACOCT3 MACOCT2 MACOCT1 MACOCT6 MACOCT5 0x014 R/W MACIA1 0x018 R/W MACTHR 0x01C R/W THRESH MACMCTL 0x020 R/W REGADR MACMDV 0x024 R/W DIV MACMADD 0x028 RO MACMTXD 0x02C R/W MDTX MACMRXD 0x030 R/W MDRX MACNP 0x034 RO NPR MACTR 0x038 R/W NEWTX MR0 0x00 R/W RESET LOOPBK SPEEDSL ANEGEN PWRDN ISO RANEG DUPLEX COLT MR1 0x01 RO MR2 100X_F 100X_H 10T_F 10T_H MFPS ANEGC RFAULT ANEGA LINK JAB EXTD 0x02 548 June 14, 2007 Luminary Micro Confidential-Advance Product Information LM3S8938 Microcontroller Name 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 PRX LPANEGA PCSBP RXCC Offset RO OUI[21:6] MR3 0x03 RO OUI[5:0] MN RN MR4 0x04 R/W NP RF A3 A2 A1 A0 S[4:0] MR5 0x05 RO NP ACK RF A[7:0] S[4:0] MR6 0x06 RO PDF LPNPA MR16 0x10 R/W RPTR INPOL TXHIM SQEI NL10 APOL RVSPOL MR17 0x11 R/W JABBER_IE RXER_IE PRX_IE PDF_IE LPACK_IE LSCHG_IE RFAULT_IE ANEGCOMP_E I JABBER_INT RXER_INT PRX_INT PDF_INT LPACK_INT LSCHG_INT RFAULT_INT ANEGCOMP_N IT MR18 0x12 RO ANEGF DPLX RATE RXSD RX_LOCK MR19 0x13 R/W TXO[1:0] MR23 0x17 R/W LED1[3:0] LED0[3:0] MR24 0x18 R/W PD_MODE AUTO_SW MDIX MDIX_CM MDIX_SD Analog Comparators Base: 0x4003.C000 ACMIS 0x00 R/W1C IN2 IN1 IN0 IN2 IN1 IN0 IN2 IN1 IN0 ACRIS 0x04 RO ACINTEN 0x08 R/W ACREFCTL 0x10 R/W EN RNG VREF ACSTAT0 0x20 RO OVAL ACSTAT1 0x40 RO OVAL ACSTAT2 0x60 RO OVAL June 14, 2007 549 Luminary Micro Confidential-Advance Product Information Register Quick Reference Name 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 Offset ACCTL0 0x24 R/W TOEN ASRCP TSLVAL TSEN ISLVAL ISEN CINV TOEN ASRCP TSLVAL TSEN ISLVAL ISEN CINV TOEN ASRCP TSLVAL TSEN ISLVAL ISEN CINV ACCTL1 0x44 R/W ACCTL2 0x64 R/W 550 June 14, 2007 Luminary Micro Confidential-Advance Product Information