TI1 LM3S5791-IQC80-C5 Stellaris lm3s5791 microcontroller Datasheet

TE X AS I NS TRUM E NTS - P RO DUCTION D ATA
®
Stellaris LM3S5791 Microcontroller
D ATA SHE E T
D S -LM3S 5791 - 1 5 8 5 2 . 2 7 4 3
S P M S 097O
C o p yri g h t © 2 0 07-2014
Te xa s In stru me n ts In co rporated
Copyright
Copyright © 2007-2014 Texas Instruments Incorporated All rights reserved. Stellaris and StellarisWare® are registered trademarks of Texas Instruments
Incorporated. 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.
PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard
warranty. Production processing does not necessarily include testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor
products and disclaimers thereto appears at the end of this data sheet.
Texas Instruments Incorporated
108 Wild Basin, Suite 350
Austin, TX 78746
http://www.ti.com/stellaris
http://www-k.ext.ti.com/sc/technical-support/product-information-centers.htm
2
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table of Contents
Revision History ............................................................................................................................. 39
About This Document .................................................................................................................... 50
Audience ..............................................................................................................................................
About This Manual ................................................................................................................................
Related Documents ...............................................................................................................................
Documentation Conventions ..................................................................................................................
50
50
50
51
1
Architectural Overview .......................................................................................... 53
1.1
1.2
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.3.8
1.3.9
1.4
Overview ...................................................................................................................... 53
Target Applications ........................................................................................................ 55
Features ....................................................................................................................... 55
ARM Cortex-M3 Processor Core .................................................................................... 55
On-Chip Memory ........................................................................................................... 57
External Peripheral Interface ......................................................................................... 58
Serial Communications Peripherals ................................................................................ 60
System Integration ........................................................................................................ 65
Advanced Motion Control ............................................................................................... 69
Analog .......................................................................................................................... 71
JTAG and ARM Serial Wire Debug ................................................................................ 73
Packaging and Temperature .......................................................................................... 74
Hardware Details .......................................................................................................... 74
2
The Cortex-M3 Processor ...................................................................................... 75
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.3.6
2.4
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.4.6
2.4.7
2.5
2.5.1
2.5.2
Block Diagram .............................................................................................................. 76
Overview ...................................................................................................................... 77
System-Level Interface .................................................................................................. 77
Integrated Configurable Debug ...................................................................................... 77
Trace Port Interface Unit (TPIU) ..................................................................................... 78
Cortex-M3 System Component Details ........................................................................... 78
Programming Model ...................................................................................................... 79
Processor Mode and Privilege Levels for Software Execution ........................................... 79
Stacks .......................................................................................................................... 79
Register Map ................................................................................................................ 80
Register Descriptions .................................................................................................... 81
Exceptions and Interrupts .............................................................................................. 94
Data Types ................................................................................................................... 94
Memory Model .............................................................................................................. 94
Memory Regions, Types and Attributes ........................................................................... 96
Memory System Ordering of Memory Accesses .............................................................. 97
Behavior of Memory Accesses ....................................................................................... 97
Software Ordering of Memory Accesses ......................................................................... 98
Bit-Banding ................................................................................................................... 99
Data Storage .............................................................................................................. 101
Synchronization Primitives ........................................................................................... 102
Exception Model ......................................................................................................... 103
Exception States ......................................................................................................... 104
Exception Types .......................................................................................................... 104
July 03, 2014
3
Texas Instruments-Production Data
Table of Contents
2.5.3
2.5.4
2.5.5
2.5.6
2.5.7
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.7
2.7.1
2.7.2
2.8
Exception Handlers .....................................................................................................
Vector Table ................................................................................................................
Exception Priorities ......................................................................................................
Interrupt Priority Grouping ............................................................................................
Exception Entry and Return .........................................................................................
Fault Handling .............................................................................................................
Fault Types .................................................................................................................
Fault Escalation and Hard Faults ..................................................................................
Fault Status Registers and Fault Address Registers ......................................................
Lockup .......................................................................................................................
Power Management ....................................................................................................
Entering Sleep Modes .................................................................................................
Wake Up from Sleep Mode ..........................................................................................
Instruction Set Summary ..............................................................................................
107
107
108
109
109
111
111
112
113
113
113
113
114
115
3
Cortex-M3 Peripherals ......................................................................................... 118
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.2
3.3
3.4
3.5
3.6
Functional Description ................................................................................................. 118
System Timer (SysTick) ............................................................................................... 118
Nested Vectored Interrupt Controller (NVIC) .................................................................. 119
System Control Block (SCB) ........................................................................................ 121
Memory Protection Unit (MPU) ..................................................................................... 121
Register Map .............................................................................................................. 126
System Timer (SysTick) Register Descriptions .............................................................. 128
NVIC Register Descriptions .......................................................................................... 132
System Control Block (SCB) Register Descriptions ........................................................ 145
Memory Protection Unit (MPU) Register Descriptions .................................................... 174
4
JTAG Interface ...................................................................................................... 184
4.1
4.2
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.4
4.5
4.5.1
4.5.2
Block Diagram ............................................................................................................
Signal Description .......................................................................................................
Functional Description .................................................................................................
JTAG Interface Pins .....................................................................................................
JTAG TAP Controller ...................................................................................................
Shift Registers ............................................................................................................
Operational Considerations ..........................................................................................
Initialization and Configuration .....................................................................................
Register Descriptions ..................................................................................................
Instruction Register (IR) ...............................................................................................
Data Registers ............................................................................................................
185
185
186
186
188
188
189
191
192
192
194
5
System Control ..................................................................................................... 196
5.1
5.2
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
5.3
5.4
Signal Description .......................................................................................................
Functional Description .................................................................................................
Device Identification ....................................................................................................
Reset Control ..............................................................................................................
Non-Maskable Interrupt ...............................................................................................
Power Control .............................................................................................................
Clock Control ..............................................................................................................
System Control ...........................................................................................................
Initialization and Configuration .....................................................................................
Register Map ..............................................................................................................
4
196
196
197
197
202
202
203
209
211
211
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
5.5
Register Descriptions .................................................................................................. 213
6
Internal Memory ................................................................................................... 301
6.1
6.2
6.2.1
6.2.2
6.2.3
6.3
6.4
6.5
Block Diagram ............................................................................................................ 301
Functional Description ................................................................................................. 301
SRAM ........................................................................................................................ 302
ROM .......................................................................................................................... 302
Flash Memory ............................................................................................................. 304
Register Map .............................................................................................................. 309
Flash Memory Register Descriptions (Flash Control Offset) ............................................ 310
Memory Register Descriptions (System Control Offset) .................................................. 322
7
Micro Direct Memory Access (μDMA) ................................................................ 338
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
7.2.8
7.2.9
7.2.10
7.3
7.3.1
7.3.2
7.3.3
7.3.4
7.3.5
7.4
7.5
7.6
Block Diagram ............................................................................................................ 339
Functional Description ................................................................................................. 339
Channel Assignments .................................................................................................. 340
Priority ........................................................................................................................ 341
Arbitration Size ............................................................................................................ 341
Request Types ............................................................................................................ 342
Channel Configuration ................................................................................................. 343
Transfer Modes ........................................................................................................... 344
Transfer Size and Increment ........................................................................................ 353
Peripheral Interface ..................................................................................................... 353
Software Request ........................................................................................................ 353
Interrupts and Errors .................................................................................................... 354
Initialization and Configuration ..................................................................................... 354
Module Initialization ..................................................................................................... 354
Configuring a Memory-to-Memory Transfer ................................................................... 354
Configuring a Peripheral for Simple Transmit ................................................................ 356
Configuring a Peripheral for Ping-Pong Receive ............................................................ 357
Configuring Channel Assignments ................................................................................ 360
Register Map .............................................................................................................. 360
μDMA Channel Control Structure ................................................................................. 361
μDMA Register Descriptions ........................................................................................ 368
8
General-Purpose Input/Outputs (GPIOs) ........................................................... 397
8.1
8.2
8.2.1
8.2.2
8.2.3
8.2.4
8.2.5
8.2.6
8.3
8.4
8.5
Signal Description ....................................................................................................... 397
Functional Description ................................................................................................. 402
Data Control ............................................................................................................... 404
Interrupt Control .......................................................................................................... 405
Mode Control .............................................................................................................. 406
Commit Control ........................................................................................................... 406
Pad Control ................................................................................................................. 407
Identification ............................................................................................................... 407
Initialization and Configuration ..................................................................................... 407
Register Map .............................................................................................................. 408
Register Descriptions .................................................................................................. 410
9
External Peripheral Interface (EPI) ..................................................................... 453
9.1
9.2
EPI Block Diagram ...................................................................................................... 454
Signal Description ....................................................................................................... 455
July 03, 2014
5
Texas Instruments-Production Data
Table of Contents
9.3
9.3.1
9.3.2
9.4
9.4.1
9.4.2
9.4.3
9.5
9.6
Functional Description .................................................................................................
Non-Blocking Reads ....................................................................................................
DMA Operation ...........................................................................................................
Initialization and Configuration .....................................................................................
SDRAM Mode .............................................................................................................
Host Bus Mode ...........................................................................................................
General-Purpose Mode ...............................................................................................
Register Map ..............................................................................................................
Register Descriptions ..................................................................................................
457
458
459
459
460
464
475
483
484
10
General-Purpose Timers ...................................................................................... 526
10.1
10.2
10.3
10.3.1
10.3.2
10.3.3
10.3.4
10.4
10.4.1
10.4.2
10.4.3
10.4.4
10.4.5
10.5
10.6
Block Diagram ............................................................................................................
Signal Description .......................................................................................................
Functional Description .................................................................................................
GPTM Reset Conditions ..............................................................................................
Timer Modes ...............................................................................................................
DMA Operation ...........................................................................................................
Accessing Concatenated Register Values .....................................................................
Initialization and Configuration .....................................................................................
One-Shot/Periodic Timer Mode ....................................................................................
Real-Time Clock (RTC) Mode ......................................................................................
Input Edge-Count Mode ...............................................................................................
Input Edge Timing Mode ..............................................................................................
PWM Mode .................................................................................................................
Register Map ..............................................................................................................
Register Descriptions ..................................................................................................
527
527
530
531
531
538
538
538
539
539
540
540
541
541
542
11
Watchdog Timers ................................................................................................. 573
11.1
11.2
11.2.1
11.3
11.4
11.5
Block Diagram ............................................................................................................
Functional Description .................................................................................................
Register Access Timing ...............................................................................................
Initialization and Configuration .....................................................................................
Register Map ..............................................................................................................
Register Descriptions ..................................................................................................
574
574
575
575
575
576
12
Analog-to-Digital Converter (ADC) ..................................................................... 598
12.1
12.2
12.3
12.3.1
12.3.2
12.3.3
12.3.4
12.3.5
12.3.6
12.3.7
12.4
12.4.1
12.4.2
12.5
12.6
Block Diagram ............................................................................................................ 599
Signal Description ....................................................................................................... 600
Functional Description ................................................................................................. 602
Sample Sequencers .................................................................................................... 602
Module Control ............................................................................................................ 603
Hardware Sample Averaging Circuit ............................................................................. 605
Analog-to-Digital Converter .......................................................................................... 606
Differential Sampling ................................................................................................... 609
Internal Temperature Sensor ........................................................................................ 612
Digital Comparator Unit ............................................................................................... 612
Initialization and Configuration ..................................................................................... 617
Module Initialization ..................................................................................................... 617
Sample Sequencer Configuration ................................................................................. 618
Register Map .............................................................................................................. 618
Register Descriptions .................................................................................................. 620
6
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
13
Universal Asynchronous Receivers/Transmitters (UARTs) ............................. 678
13.1
Block Diagram ............................................................................................................
13.2
Signal Description .......................................................................................................
13.3
Functional Description .................................................................................................
13.3.1 Transmit/Receive Logic ...............................................................................................
13.3.2 Baud-Rate Generation .................................................................................................
13.3.3 Data Transmission ......................................................................................................
13.3.4 Serial IR (SIR) .............................................................................................................
13.3.5 ISO 7816 Support .......................................................................................................
13.3.6 Modem Handshake Support .........................................................................................
13.3.7 LIN Support ................................................................................................................
13.3.8 FIFO Operation ...........................................................................................................
13.3.9 Interrupts ....................................................................................................................
13.3.10 Loopback Operation ....................................................................................................
13.3.11 DMA Operation ...........................................................................................................
13.4
Initialization and Configuration .....................................................................................
13.5
Register Map ..............................................................................................................
13.6
Register Descriptions ..................................................................................................
679
679
681
682
682
683
683
684
685
686
687
688
689
689
689
690
692
14
Synchronous Serial Interface (SSI) .................................................................... 742
14.1
14.2
14.3
14.3.1
14.3.2
14.3.3
14.3.4
14.3.5
14.4
14.5
14.6
Block Diagram ............................................................................................................
Signal Description .......................................................................................................
Functional Description .................................................................................................
Bit Rate Generation .....................................................................................................
FIFO Operation ...........................................................................................................
Interrupts ....................................................................................................................
Frame Formats ...........................................................................................................
DMA Operation ...........................................................................................................
Initialization and Configuration .....................................................................................
Register Map ..............................................................................................................
Register Descriptions ..................................................................................................
15
Inter-Integrated Circuit (I2C) Interface ................................................................ 784
15.1
15.2
15.3
15.3.1
15.3.2
15.3.3
15.3.4
15.3.5
15.4
15.5
15.6
15.7
Block Diagram ............................................................................................................
Signal Description .......................................................................................................
Functional Description .................................................................................................
I2C Bus Functional Overview ........................................................................................
Available Speed Modes ...............................................................................................
Interrupts ....................................................................................................................
Loopback Operation ....................................................................................................
Command Sequence Flow Charts ................................................................................
Initialization and Configuration .....................................................................................
Register Map ..............................................................................................................
Register Descriptions (I2C Master) ...............................................................................
Register Descriptions (I2C Slave) .................................................................................
16
Inter-Integrated Circuit Sound (I2S) Interface .................................................... 822
16.1
16.2
16.3
Block Diagram ............................................................................................................ 823
Signal Description ....................................................................................................... 823
Functional Description ................................................................................................. 825
July 03, 2014
743
743
744
745
745
745
746
753
754
755
756
785
785
786
786
788
789
790
791
798
799
800
813
7
Texas Instruments-Production Data
Table of Contents
16.3.1
16.3.2
16.4
16.5
16.6
Transmit .....................................................................................................................
Receive ......................................................................................................................
Initialization and Configuration .....................................................................................
Register Map ..............................................................................................................
Register Descriptions ..................................................................................................
826
830
832
833
834
17
Controller Area Network (CAN) Module ............................................................. 859
17.1
Block Diagram ............................................................................................................ 860
17.2
Signal Description ....................................................................................................... 860
17.3
Functional Description ................................................................................................. 861
17.3.1 Initialization ................................................................................................................. 862
17.3.2 Operation ................................................................................................................... 863
17.3.3 Transmitting Message Objects ..................................................................................... 864
17.3.4 Configuring a Transmit Message Object ........................................................................ 864
17.3.5 Updating a Transmit Message Object ........................................................................... 865
17.3.6 Accepting Received Message Objects .......................................................................... 866
17.3.7 Receiving a Data Frame .............................................................................................. 866
17.3.8 Receiving a Remote Frame .......................................................................................... 866
17.3.9 Receive/Transmit Priority ............................................................................................. 867
17.3.10 Configuring a Receive Message Object ........................................................................ 867
17.3.11 Handling of Received Message Objects ........................................................................ 868
17.3.12 Handling of Interrupts .................................................................................................. 870
17.3.13 Test Mode ................................................................................................................... 871
17.3.14 Bit Timing Configuration Error Considerations ............................................................... 873
17.3.15 Bit Time and Bit Rate ................................................................................................... 873
17.3.16 Calculating the Bit Timing Parameters .......................................................................... 875
17.4
Register Map .............................................................................................................. 878
17.5
CAN Register Descriptions .......................................................................................... 879
18
Universal Serial Bus (USB) Controller ............................................................... 910
18.1
18.2
18.3
18.3.1
18.3.2
18.3.3
18.3.4
18.4
18.4.1
18.4.2
18.5
18.6
Block Diagram ............................................................................................................ 911
Signal Description ....................................................................................................... 911
Functional Description ................................................................................................. 913
Operation as a Device ................................................................................................. 913
Operation as a Host .................................................................................................... 918
OTG Mode .................................................................................................................. 922
DMA Operation ........................................................................................................... 924
Initialization and Configuration ..................................................................................... 925
Pin Configuration ......................................................................................................... 925
Endpoint Configuration ................................................................................................ 926
Register Map .............................................................................................................. 926
Register Descriptions .................................................................................................. 937
19
Analog Comparators .......................................................................................... 1049
19.1
19.2
19.3
19.3.1
19.4
19.5
19.6
Block Diagram ...........................................................................................................
Signal Description .....................................................................................................
Functional Description ...............................................................................................
Internal Reference Programming ................................................................................
Initialization and Configuration ....................................................................................
Register Map ............................................................................................................
Register Descriptions .................................................................................................
8
1050
1050
1051
1052
1053
1054
1055
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
20
Pulse Width Modulator (PWM) .......................................................................... 1063
20.1
20.2
20.3
20.3.1
20.3.2
20.3.3
20.3.4
20.3.5
20.3.6
20.3.7
20.3.8
20.4
20.5
20.6
Block Diagram ........................................................................................................... 1064
Signal Description ..................................................................................................... 1065
Functional Description ............................................................................................... 1068
PWM Timer ............................................................................................................... 1068
PWM Comparators .................................................................................................... 1069
PWM Signal Generator .............................................................................................. 1070
Dead-Band Generator ............................................................................................... 1071
Interrupt/ADC-Trigger Selector ................................................................................... 1071
Synchronization Methods .......................................................................................... 1072
Fault Conditions ........................................................................................................ 1073
Output Control Block .................................................................................................. 1073
Initialization and Configuration .................................................................................... 1074
Register Map ............................................................................................................ 1075
Register Descriptions ................................................................................................. 1078
21
Quadrature Encoder Interface (QEI) ................................................................. 1141
21.1
21.2
21.3
21.4
21.5
21.6
Block Diagram ...........................................................................................................
Signal Description .....................................................................................................
Functional Description ...............................................................................................
Initialization and Configuration ....................................................................................
Register Map ............................................................................................................
Register Descriptions .................................................................................................
22
Pin Diagram ........................................................................................................ 1164
1141
1142
1143
1146
1146
1147
23
Signal Tables ...................................................................................................... 1166
23.1
23.1.1
23.1.2
23.1.3
23.1.4
23.1.5
23.2
23.2.1
23.2.2
23.2.3
23.2.4
23.2.5
23.3
100-Pin LQFP Package Pin Tables .............................................................................
Signals by Pin Number ..............................................................................................
Signals by Signal Name .............................................................................................
Signals by Function, Except for GPIO .........................................................................
GPIO Pins and Alternate Functions ............................................................................
Possible Pin Assignments for Alternate Functions .......................................................
108-Ball BGA Package Pin Tables ..............................................................................
Signals by Pin Number ..............................................................................................
Signals by Signal Name .............................................................................................
Signals by Function, Except for GPIO .........................................................................
GPIO Pins and Alternate Functions ............................................................................
Possible Pin Assignments for Alternate Functions .......................................................
Connections for Unused Signals .................................................................................
24
Operating Characteristics ................................................................................. 1246
1167
1167
1179
1190
1199
1202
1205
1205
1218
1229
1238
1241
1244
25
Electrical Characteristics .................................................................................. 1247
25.1
25.2
25.3
25.4
25.5
25.6
25.7
25.8
Maximum Ratings ......................................................................................................
Recommended Operating Conditions .........................................................................
Load Conditions ........................................................................................................
JTAG and Boundary Scan ..........................................................................................
Power and Brown-Out ...............................................................................................
Reset ........................................................................................................................
On-Chip Low Drop-Out (LDO) Regulator .....................................................................
Clocks ......................................................................................................................
July 03, 2014
1247
1247
1248
1248
1250
1251
1252
1252
9
Texas Instruments-Production Data
Table of Contents
25.8.1 PLL Specifications ..................................................................................................... 1252
25.8.2 PIOSC Specifications ................................................................................................ 1253
25.8.3 Internal 30-kHz Oscillator Specifications ..................................................................... 1253
25.8.4 Main Oscillator Specifications ..................................................................................... 1254
25.8.5 System Clock Specification with ADC Operation .......................................................... 1255
25.8.6 System Clock Specification with USB Operation .......................................................... 1255
25.9
Sleep Modes ............................................................................................................. 1255
25.10 Flash Memory ........................................................................................................... 1255
25.11 Input/Output Characteristics ....................................................................................... 1256
25.12 External Peripheral Interface (EPI) .............................................................................. 1256
25.13 Analog-to-Digital Converter (ADC) .............................................................................. 1262
25.14 Synchronous Serial Interface (SSI) ............................................................................. 1263
25.15 Inter-Integrated Circuit (I2C) Interface ......................................................................... 1265
25.16 Inter-Integrated Circuit Sound (I2S) Interface ............................................................... 1266
25.17 Universal Serial Bus (USB) Controller ......................................................................... 1267
25.18 Analog Comparator ................................................................................................... 1268
25.19 Current Consumption ................................................................................................. 1268
25.19.1 Nominal Power Consumption ..................................................................................... 1268
25.19.2 Maximum Current Consumption ................................................................................. 1269
A
Register Quick Reference ................................................................................. 1270
B
Ordering and Contact Information ................................................................... 1323
B.1
B.2
B.3
B.4
Ordering Information ..................................................................................................
Part Markings ............................................................................................................
Kits ...........................................................................................................................
Support Information ...................................................................................................
1323
1323
1323
1324
C
Package Information .......................................................................................... 1325
C.1
C.1.1
C.1.2
C.1.3
C.2
C.2.1
C.2.2
C.2.3
100-Pin LQFP Package .............................................................................................
Package Dimensions .................................................................................................
Tray Dimensions .......................................................................................................
Tape and Reel Dimensions ........................................................................................
108-Ball BGA Package ..............................................................................................
Package Dimensions .................................................................................................
Tray Dimensions .......................................................................................................
Tape and Reel Dimensions ........................................................................................
10
1325
1325
1327
1327
1329
1329
1331
1332
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
List of Figures
Figure 1-1.
Figure 2-1.
Figure 2-2.
Figure 2-3.
Figure 2-4.
Figure 2-5.
Figure 2-6.
Figure 2-7.
Figure 3-1.
Figure 4-1.
Figure 4-2.
Figure 4-3.
Figure 4-4.
Figure 4-5.
Figure 5-1.
Figure 5-2.
Figure 5-3.
Figure 5-4.
Figure 5-5.
Figure 6-1.
Figure 7-1.
Figure 7-2.
Figure 7-3.
Figure 7-4.
Figure 7-5.
Figure 7-6.
Figure 8-1.
Figure 8-2.
Figure 8-3.
Figure 8-4.
Figure 9-1.
Figure 9-2.
Figure 9-3.
Figure 9-4.
Figure 9-5.
Figure 9-6.
Figure 9-7.
Figure 9-8.
Figure 9-9.
Figure 9-10.
Figure 9-11.
Figure 9-12.
Figure 9-13.
Stellaris LM3S5791 Microcontroller High-Level Block Diagram ............................... 54
CPU Block Diagram ............................................................................................. 77
TPIU Block Diagram ............................................................................................ 78
Cortex-M3 Register Set ........................................................................................ 80
Bit-Band Mapping .............................................................................................. 101
Data Storage ..................................................................................................... 102
Vector Table ...................................................................................................... 108
Exception Stack Frame ...................................................................................... 110
SRD Use Example ............................................................................................. 124
JTAG Module Block Diagram .............................................................................. 185
Test Access Port State Machine ......................................................................... 188
IDCODE Register Format ................................................................................... 194
BYPASS Register Format ................................................................................... 195
Boundary Scan Register Format ......................................................................... 195
Basic RST Configuration .................................................................................... 199
External Circuitry to Extend Power-On Reset ....................................................... 199
Reset Circuit Controlled by Switch ...................................................................... 200
Power Architecture ............................................................................................ 203
Main Clock Tree ................................................................................................ 205
Internal Memory Block Diagram .......................................................................... 301
μDMA Block Diagram ......................................................................................... 339
Example of Ping-Pong μDMA Transaction ........................................................... 346
Memory Scatter-Gather, Setup and Configuration ................................................ 348
Memory Scatter-Gather, μDMA Copy Sequence .................................................. 349
Peripheral Scatter-Gather, Setup and Configuration ............................................. 351
Peripheral Scatter-Gather, μDMA Copy Sequence ............................................... 352
Digital I/O Pads ................................................................................................. 403
Analog/Digital I/O Pads ...................................................................................... 404
GPIODATA Write Example ................................................................................. 405
GPIODATA Read Example ................................................................................. 405
EPI Block Diagram ............................................................................................. 455
SDRAM Non-Blocking Read Cycle ...................................................................... 463
SDRAM Normal Read Cycle ............................................................................... 463
SDRAM Write Cycle ........................................................................................... 464
Example Schematic for Muxed Host-Bus 16 Mode ............................................... 470
Host-Bus Read Cycle, MODE = 0x1, WRHIGH = 0, RDHIGH = 0 .......................... 472
Host-Bus Write Cycle, MODE = 0x1, WRHIGH = 0, RDHIGH = 0 .......................... 473
Host-Bus Write Cycle with Multiplexed Address and Data, MODE = 0x0, WRHIGH
= 0, RDHIGH = 0 ............................................................................................... 473
Host-Bus Write Cycle with Multiplexed Address and Data and ALE with Dual
CSn .................................................................................................................. 474
Continuous Read Mode Accesses ...................................................................... 474
Write Followed by Read to External FIFO ............................................................ 475
Two-Entry FIFO ................................................................................................. 475
Single-Cycle Write Access, FRM50=0, FRMCNT=0, WRCYC=0 ........................... 479
July 03, 2014
11
Texas Instruments-Production Data
Table of Contents
Figure 9-14.
Figure 9-15.
Figure 9-16.
Figure 9-17.
Figure 9-18.
Figure 9-19.
Figure 9-20.
Figure 9-21.
Figure 9-22.
Figure 9-23.
Figure 9-24.
Figure 10-1.
Figure 10-2.
Figure 10-3.
Figure 10-4.
Figure 10-5.
Figure 11-1.
Figure 12-1.
Figure 12-2.
Figure 12-3.
Figure 12-4.
Figure 12-5.
Figure 12-6.
Figure 12-7.
Figure 12-8.
Figure 12-9.
Figure 12-10.
Figure 12-11.
Figure 12-12.
Figure 12-13.
Figure 12-14.
Figure 12-15.
Figure 12-16.
Figure 13-1.
Figure 13-2.
Figure 13-3.
Figure 13-4.
Figure 13-5.
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.
Two-Cycle Read, Write Accesses, FRM50=0, FRMCNT=0, RDCYC=1,
WRCYC=1 ........................................................................................................ 479
Read Accesses, FRM50=0, FRMCNT=0, RDCYC=1 ............................................ 480
FRAME Signal Operation, FRM50=0 and FRMCNT=0 ......................................... 480
FRAME Signal Operation, FRM50=0 and FRMCNT=1 ......................................... 480
FRAME Signal Operation, FRM50=0 and FRMCNT=2 ......................................... 481
FRAME Signal Operation, FRM50=1 and FRMCNT=0 ......................................... 481
FRAME Signal Operation, FRM50=1 and FRMCNT=1 ......................................... 481
FRAME Signal Operation, FRM50=1 and FRMCNT=2 ......................................... 481
iRDY Signal Operation, FRM50=0, FRMCNT=0, and RD2CYC=1 ......................... 482
EPI Clock Operation, CLKGATE=1, WR2CYC=0 ................................................. 483
EPI Clock Operation, CLKGATE=1, WR2CYC=1 ................................................. 483
GPTM Module Block Diagram ............................................................................ 527
Timer Daisy Chain ............................................................................................. 533
Input Edge-Count Mode Example ....................................................................... 535
16-Bit Input Edge-Time Mode Example ............................................................... 536
16-Bit PWM Mode Example ................................................................................ 537
WDT Module Block Diagram .............................................................................. 574
Implementation of Two ADC Blocks .................................................................... 599
ADC Module Block Diagram ............................................................................... 600
ADC Sample Phases ......................................................................................... 604
Doubling the ADC Sample Rate .......................................................................... 605
Skewed Sampling .............................................................................................. 605
Sample Averaging Example ............................................................................... 606
ADC Input Equivalency Diagram ......................................................................... 607
Internal Voltage Conversion Result ..................................................................... 608
External Voltage Conversion Result .................................................................... 609
Differential Sampling Range, VIN_ODD = 1.5 V ...................................................... 610
Differential Sampling Range, VIN_ODD = 0.75 V .................................................... 611
Differential Sampling Range, VIN_ODD = 2.25 V .................................................... 611
Internal Temperature Sensor Characteristic ......................................................... 612
Low-Band Operation (CIC=0x0 and/or CTC=0x0) ................................................ 615
Mid-Band Operation (CIC=0x1 and/or CTC=0x1) ................................................. 616
High-Band Operation (CIC=0x3 and/or CTC=0x3) ................................................ 617
UART Module Block Diagram ............................................................................. 679
UART Character Frame ..................................................................................... 682
IrDA Data Modulation ......................................................................................... 684
LIN Message ..................................................................................................... 686
LIN Synchronization Field ................................................................................... 687
SSI Module Block Diagram ................................................................................. 743
TI Synchronous Serial Frame Format (Single Transfer) ........................................ 747
TI Synchronous Serial Frame Format (Continuous Transfer) ................................ 747
Freescale SPI Format (Single Transfer) with SPO=0 and SPH=0 .......................... 748
Freescale SPI Format (Continuous Transfer) with SPO=0 and SPH=0 .................. 748
Freescale SPI Frame Format with SPO=0 and SPH=1 ......................................... 749
Freescale SPI Frame Format (Single Transfer) with SPO=1 and SPH=0 ............... 750
Freescale SPI Frame Format (Continuous Transfer) with SPO=1 and SPH=0 ........ 750
Freescale SPI Frame Format with SPO=1 and SPH=1 ......................................... 751
12
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
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.
MICROWIRE Frame Format (Single Frame) ........................................................ 752
MICROWIRE Frame Format (Continuous Transfer) ............................................. 753
MICROWIRE Frame Format, SSIFss Input Setup and Hold Requirements ............ 753
I2C Block Diagram ............................................................................................. 785
I2C Bus Configuration ........................................................................................ 786
START and STOP Conditions ............................................................................. 787
Complete Data Transfer with a 7-Bit Address ....................................................... 787
R/S Bit in First Byte ............................................................................................ 788
Data Validity During Bit Transfer on the I2C Bus ................................................... 788
Master Single TRANSMIT .................................................................................. 792
Master Single RECEIVE ..................................................................................... 793
Master TRANSMIT with Repeated START ........................................................... 794
Master RECEIVE with Repeated START ............................................................. 795
Master RECEIVE with Repeated START after TRANSMIT with Repeated
START .............................................................................................................. 796
Figure 15-12. Master TRANSMIT with Repeated START after RECEIVE with Repeated
START .............................................................................................................. 797
Figure 15-13. Slave Command Sequence ................................................................................ 798
Figure 16-1. I2S Block Diagram ............................................................................................. 823
Figure 16-2. I2S Data Transfer ............................................................................................... 826
Figure 16-3. Left-Justified Data Transfer ................................................................................ 826
Figure 16-4. Right-Justified Data Transfer .............................................................................. 826
Figure 17-1. CAN Controller Block Diagram ............................................................................ 860
Figure 17-2. CAN Data/Remote Frame .................................................................................. 862
Figure 17-3. Message Objects in a FIFO Buffer ...................................................................... 870
Figure 17-4. CAN Bit Time .................................................................................................... 874
Figure 18-1. USB Module Block Diagram ............................................................................... 911
Figure 19-1. Analog Comparator Module Block Diagram ....................................................... 1050
Figure 19-2. Structure of Comparator Unit ............................................................................ 1052
Figure 19-3. Comparator Internal Reference Structure .......................................................... 1052
Figure 20-1. PWM Module Diagram ..................................................................................... 1065
Figure 20-2. PWM Generator Block Diagram ........................................................................ 1065
Figure 20-3. PWM Count-Down Mode .................................................................................. 1070
Figure 20-4. PWM Count-Up/Down Mode ............................................................................. 1070
Figure 20-5. PWM Generation Example In Count-Up/Down Mode .......................................... 1071
Figure 20-6. PWM Dead-Band Generator ............................................................................. 1071
Figure 21-1. QEI Block Diagram .......................................................................................... 1142
Figure 21-2. Quadrature Encoder and Velocity Predivider Operation ...................................... 1145
Figure 22-1. 100-Pin LQFP Package Pin Diagram ................................................................ 1164
Figure 22-2. 108-Ball BGA Package Pin Diagram (Top View) ................................................. 1165
Figure 25-1. Load Conditions ............................................................................................... 1248
Figure 25-2. JTAG Test Clock Input Timing ........................................................................... 1249
Figure 25-3. JTAG Test Access Port (TAP) Timing ................................................................ 1249
Figure 25-4. Power-On Reset Timing ................................................................................... 1250
Figure 25-5. Brown-Out Reset Timing .................................................................................. 1250
Figure 25-6. Power-On Reset and Voltage Parameters ......................................................... 1251
Figure 25-7. External Reset Timing (RST) ............................................................................ 1251
Figure 25-8. Software Reset Timing ..................................................................................... 1251
July 03, 2014
13
Texas Instruments-Production Data
Table of Contents
Figure 25-9.
Figure 25-10.
Figure 25-11.
Figure 25-12.
Figure 25-13.
Figure 25-14.
Figure 25-15.
Figure 25-16.
Figure 25-17.
Figure 25-18.
Figure 25-19.
Figure 25-20.
Figure 25-21.
Figure 25-22.
Figure 25-23.
Figure 25-24.
Figure 25-25.
Figure 25-26.
Figure 25-27.
Figure 25-28.
Figure C-1.
Figure C-2.
Figure C-3.
Figure C-4.
Figure C-5.
Figure C-6.
Watchdog Reset Timing ................................................................................... 1252
MOSC Failure Reset Timing ............................................................................. 1252
SDRAM Initialization and Load Mode Register Timing ........................................ 1257
SDRAM Read Timing ....................................................................................... 1257
SDRAM Write Timing ....................................................................................... 1258
Host-Bus 8/16 Mode Read Timing ..................................................................... 1259
Host-Bus 8/16 Mode Write Timing ..................................................................... 1259
Host-Bus 8/16 Mode Muxed Read Timing .......................................................... 1260
Host-Bus 8/16 Mode Muxed Write Timing .......................................................... 1260
General-Purpose Mode Read and Write Timing ................................................. 1261
General-Purpose Mode iRDY Timing ................................................................. 1261
ADC Input Equivalency Diagram ....................................................................... 1263
SSI Timing for TI Frame Format (FRF=01), Single Transfer Timing
Measurement .................................................................................................. 1264
SSI Timing for MICROWIRE Frame Format (FRF=10), Single Transfer ............... 1264
SSI Timing for SPI Frame Format (FRF=00), with SPH=1 ................................... 1265
I2C Timing ....................................................................................................... 1266
I2S Master Mode Transmit Timing ..................................................................... 1266
I2S Master Mode Receive Timing ...................................................................... 1267
I2S Slave Mode Transmit Timing ....................................................................... 1267
I2S Slave Mode Receive Timing ........................................................................ 1267
Stellaris LM3S5791 100-Pin LQFP Package Dimensions .................................... 1325
100-Pin LQFP Tray Dimensions ........................................................................ 1327
100-Pin LQFP Tape and Reel Dimensions ......................................................... 1328
Stellaris LM3S5791 108-Ball BGA Package Dimensions .................................... 1329
108-Ball BGA Tray Dimensions ......................................................................... 1331
108-Ball BGA Tape and Reel Dimensions .......................................................... 1332
14
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
List of Tables
Table 1.
Table 2.
Table 2-1.
Table 2-2.
Table 2-3.
Table 2-4.
Table 2-5.
Table 2-6.
Table 2-7.
Table 2-8.
Table 2-9.
Table 2-10.
Table 2-11.
Table 2-12.
Table 2-13.
Table 3-1.
Table 3-2.
Table 3-3.
Table 3-4.
Table 3-5.
Table 3-6.
Table 3-7.
Table 3-8.
Table 3-9.
Table 4-1.
Table 4-2.
Table 4-3.
Table 4-4.
Table 5-1.
Table 5-2.
Table 5-3.
Table 5-4.
Table 5-5.
Table 5-6.
Table 5-7.
Table 5-8.
Table 5-9.
Table 6-1.
Table 6-2.
Table 6-3.
Table 7-1.
Table 7-2.
Table 7-3.
Table 7-4.
Table 7-5.
Table 7-6.
Revision History .................................................................................................. 39
Documentation Conventions ................................................................................ 51
Summary of Processor Mode, Privilege Level, and Stack Use ................................ 80
Processor Register Map ....................................................................................... 81
PSR Register Combinations ................................................................................. 86
Memory Map ....................................................................................................... 94
Memory Access Behavior ..................................................................................... 97
SRAM Memory Bit-Banding Regions .................................................................... 99
Peripheral Memory Bit-Banding Regions ............................................................... 99
Exception Types ................................................................................................ 105
Interrupts .......................................................................................................... 106
Exception Return Behavior ................................................................................. 111
Faults ............................................................................................................... 111
Fault Status and Fault Address Registers ............................................................ 113
Cortex-M3 Instruction Summary ......................................................................... 115
Core Peripheral Register Regions ....................................................................... 118
Memory Attributes Summary .............................................................................. 121
TEX, S, C, and B Bit Field Encoding ................................................................... 124
Cache Policy for Memory Attribute Encoding ....................................................... 125
AP Bit Field Encoding ........................................................................................ 125
Memory Region Attributes for Stellaris Microcontrollers ........................................ 125
Peripherals Register Map ................................................................................... 126
Interrupt Priority Levels ...................................................................................... 153
Example SIZE Field Values ................................................................................ 181
JTAG_SWD_SWO Signals (100LQFP) ................................................................ 185
JTAG_SWD_SWO Signals (108BGA) ................................................................. 186
JTAG Port Pins State after Power-On Reset or RST assertion .............................. 187
JTAG Instruction Register Commands ................................................................. 192
System Control & Clocks Signals (100LQFP) ...................................................... 196
System Control & Clocks Signals (108BGA) ........................................................ 196
Reset Sources ................................................................................................... 197
Clock Source Options ........................................................................................ 204
Possible System Clock Frequencies Using the SYSDIV Field ............................... 206
Examples of Possible System Clock Frequencies Using the SYSDIV2 Field .......... 206
Examples of Possible System Clock Frequencies with DIV400=1 ......................... 207
System Control Register Map ............................................................................. 211
RCC2 Fields that Override RCC Fields ............................................................... 233
Flash Memory Protection Policy Combinations .................................................... 305
User-Programmable Flash Memory Resident Registers ....................................... 309
Flash Register Map ............................................................................................ 309
μDMA Channel Assignments .............................................................................. 340
Request Type Support ....................................................................................... 342
Control Structure Memory Map ........................................................................... 343
Channel Control Structure .................................................................................. 343
μDMA Read Example: 8-Bit Peripheral ................................................................ 353
μDMA Interrupt Assignments .............................................................................. 354
July 03, 2014
15
Texas Instruments-Production Data
Table of Contents
Table 7-7.
Table 7-8.
Table 7-9.
Table 7-10.
Table 7-11.
Table 7-12.
Channel Control Structure Offsets for Channel 30 ................................................ 355
Channel Control Word Configuration for Memory Transfer Example ...................... 355
Channel Control Structure Offsets for Channel 7 .................................................. 356
Channel Control Word Configuration for Peripheral Transmit Example .................. 357
Primary and Alternate Channel Control Structure Offsets for Channel 8 ................. 358
Channel Control Word Configuration for Peripheral Ping-Pong Receive
Example ............................................................................................................ 359
Table 7-13.
μDMA Register Map .......................................................................................... 360
Table 8-1.
GPIO Pins With Non-Zero Reset Values .............................................................. 398
Table 8-2.
GPIO Pins and Alternate Functions (100LQFP) ................................................... 398
Table 8-3.
GPIO Pins and Alternate Functions (108BGA) ..................................................... 400
Table 8-4.
GPIO Pad Configuration Examples ..................................................................... 407
Table 8-5.
GPIO Interrupt Configuration Example ................................................................ 408
Table 8-6.
GPIO Pins With Non-Zero Reset Values .............................................................. 409
Table 8-7.
GPIO Register Map ........................................................................................... 409
Table 8-8.
GPIO Pins With Non-Zero Reset Values .............................................................. 421
Table 8-9.
GPIO Pins With Non-Zero Reset Values .............................................................. 427
Table 8-10.
GPIO Pins With Non-Zero Reset Values .............................................................. 429
Table 8-11.
GPIO Pins With Non-Zero Reset Values .............................................................. 432
Table 8-12.
GPIO Pins With Non-Zero Reset Values .............................................................. 439
Table 9-1.
External Peripheral Interface Signals (100LQFP) ................................................. 455
Table 9-2.
External Peripheral Interface Signals (108BGA) ................................................... 456
Table 9-3.
EPI SDRAM Signal Connections ......................................................................... 461
Table 9-4.
Capabilities of Host Bus 8 and Host Bus 16 Modes .............................................. 465
Table 9-5.
EPI Host-Bus 8 Signal Connections .................................................................... 466
Table 9-6.
EPI Host-Bus 16 Signal Connections .................................................................. 468
Table 9-7.
EPI General Purpose Signal Connections ........................................................... 477
Table 9-8.
External Peripheral Interface (EPI) Register Map ................................................. 483
Table 10-1.
Available CCP Pins ............................................................................................ 527
Table 10-2.
General-Purpose Timers Signals (100LQFP) ....................................................... 528
Table 10-3.
General-Purpose Timers Signals (108BGA) ......................................................... 529
Table 10-4.
General-Purpose Timer Capabilities .................................................................... 531
Table 10-5.
Counter Values When the Timer is Enabled in Periodic or One-Shot Modes .......... 532
Table 10-6.
16-Bit Timer With Prescaler Configurations ......................................................... 532
Table 10-7.
Counter Values When the Timer is Enabled in RTC Mode .................................... 533
Table 10-8.
Counter Values When the Timer is Enabled in Input Edge-Count Mode ................. 534
Table 10-9.
Counter Values When the Timer is Enabled in Input Event-Count Mode ................ 535
Table 10-10. Counter Values When the Timer is Enabled in PWM Mode ................................... 537
Table 10-11. Timers Register Map .......................................................................................... 541
Table 11-1.
Watchdog Timers Register Map .......................................................................... 576
Table 12-1.
ADC Signals (100LQFP) .................................................................................... 600
Table 12-2.
ADC Signals (108BGA) ...................................................................................... 601
Table 12-3.
Samples and FIFO Depth of Sequencers ............................................................ 602
Table 12-4.
Differential Sampling Pairs ................................................................................. 609
Table 12-5.
ADC Register Map ............................................................................................. 618
Table 13-1.
UART Signals (100LQFP) .................................................................................. 680
Table 13-2.
UART Signals (108BGA) .................................................................................... 680
Table 13-3.
Flow Control Mode ............................................................................................. 686
16
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 13-4.
Table 14-1.
Table 14-2.
Table 14-3.
Table 15-1.
Table 15-2.
Table 15-3.
Table 15-4.
Table 15-5.
Table 16-1.
Table 16-2.
Table 16-3.
Table 16-4.
Table 16-5.
Table 16-6.
Table 16-7.
Table 16-8.
Table 16-9.
Table 16-10.
Table 17-1.
Table 17-2.
Table 17-3.
Table 17-4.
Table 17-5.
Table 17-6.
Table 18-1.
Table 18-2.
Table 18-3.
Table 18-4.
Table 18-5.
Table 18-6.
Table 19-1.
Table 19-2.
Table 19-3.
Table 19-4.
Table 20-1.
Table 20-2.
Table 20-3.
Table 21-1.
Table 21-2.
Table 21-3.
Table 23-1.
Table 23-2.
Table 23-3.
Table 23-4.
Table 23-5.
Table 23-6.
Table 23-7.
UART Register Map ........................................................................................... 691
SSI Signals (100LQFP) ...................................................................................... 744
SSI Signals (108BGA) ........................................................................................ 744
SSI Register Map .............................................................................................. 755
I2C Signals (100LQFP) ...................................................................................... 785
I2C Signals (108BGA) ........................................................................................ 785
Examples of I2C Master Timer Period versus Speed Mode ................................... 789
Inter-Integrated Circuit (I2C) Interface Register Map ............................................. 799
Write Field Decoding for I2CMCS[3:0] Field ......................................................... 805
I2S Signals (100LQFP) ...................................................................................... 824
I2S Signals (108BGA) ........................................................................................ 824
I2S Transmit FIFO Interface ................................................................................ 827
Crystal Frequency (Values from 3.5795 MHz to 5 MHz) ........................................ 828
Crystal Frequency (Values from 5.12 MHz to 8.192 MHz) ..................................... 828
Crystal Frequency (Values from 10 MHz to 14.3181 MHz) .................................... 829
Crystal Frequency (Values from 16 MHz to 16.384 MHz) ...................................... 829
I2S Receive FIFO Interface ................................................................................. 831
Audio Formats Configuration .............................................................................. 833
Inter-Integrated Circuit Sound (I2S) Interface Register Map ................................... 834
Controller Area Network Signals (100LQFP) ........................................................ 861
Controller Area Network Signals (108BGA) ......................................................... 861
Message Object Configurations .......................................................................... 867
CAN Protocol Ranges ........................................................................................ 874
CANBIT Register Values .................................................................................... 874
CAN Register Map ............................................................................................. 878
USB Signals (100LQFP) .................................................................................... 912
USB Signals (108BGA) ...................................................................................... 912
Remainder (MAXLOAD/4) .................................................................................. 924
Actual Bytes Read ............................................................................................. 924
Packet Sizes That Clear RXRDY ........................................................................ 925
Universal Serial Bus (USB) Controller Register Map ............................................ 926
Analog Comparators Signals (100LQFP) ........................................................... 1050
Analog Comparators Signals (108BGA) ............................................................. 1051
Internal Reference Voltage and ACREFCTL Field Values ................................... 1053
Analog Comparators Register Map ................................................................... 1054
PWM Signals (100LQFP) ................................................................................. 1066
PWM Signals (108BGA) ................................................................................... 1067
PWM Register Map .......................................................................................... 1075
QEI Signals (100LQFP) .................................................................................... 1142
QEI Signals (108BGA) ..................................................................................... 1143
QEI Register Map ............................................................................................ 1147
GPIO Pins With Default Alternate Functions ...................................................... 1166
Signals by Pin Number ..................................................................................... 1167
Signals by Signal Name ................................................................................... 1179
Signals by Function, Except for GPIO ............................................................... 1190
GPIO Pins and Alternate Functions ................................................................... 1199
Possible Pin Assignments for Alternate Functions .............................................. 1202
Signals by Pin Number ..................................................................................... 1205
July 03, 2014
17
Texas Instruments-Production Data
Table of Contents
Table 23-8.
Table 23-9.
Table 23-10.
Table 23-11.
Table 23-12.
Table 23-13.
Table 24-1.
Table 24-2.
Table 24-3.
Table 25-1.
Table 25-2.
Table 25-3.
Table 25-4.
Table 25-5.
Table 25-6.
Table 25-7.
Table 25-8.
Table 25-9.
Table 25-10.
Table 25-11.
Table 25-12.
Table 25-13.
Table 25-14.
Table 25-15.
Table 25-16.
Table 25-17.
Table 25-18.
Table 25-19.
Table 25-20.
Table 25-21.
Table 25-22.
Table 25-23.
Table 25-24.
Table 25-25.
Table 25-26.
Table 25-27.
Table 25-28.
Table 25-29.
Table 25-30.
Table 25-31.
Table 25-32.
Table 25-33.
Table 25-34.
Table 25-35.
Signals by Signal Name ................................................................................... 1218
Signals by Function, Except for GPIO ............................................................... 1229
GPIO Pins and Alternate Functions ................................................................... 1238
Possible Pin Assignments for Alternate Functions .............................................. 1241
Connections for Unused Signals (100-Pin LQFP) ............................................... 1244
Connections for Unused Signals (108-Ball BGA) ................................................ 1245
Temperature Characteristics ............................................................................. 1246
Thermal Characteristics ................................................................................... 1246
ESD Absolute Maximum Ratings ...................................................................... 1246
Maximum Ratings ............................................................................................ 1247
Recommended DC Operating Conditions .......................................................... 1247
JTAG Characteristics ....................................................................................... 1248
Power Characteristics ...................................................................................... 1250
Reset Characteristics ....................................................................................... 1251
LDO Regulator Characteristics ......................................................................... 1252
Phase Locked Loop (PLL) Characteristics ......................................................... 1252
Actual PLL Frequency ...................................................................................... 1253
PIOSC Clock Characteristics ............................................................................ 1253
30-kHz Clock Characteristics ............................................................................ 1253
Main Oscillator Clock Characteristics ................................................................ 1254
Supported MOSC Crystal Frequencies .............................................................. 1254
System Clock Characteristics with ADC Operation ............................................. 1255
System Clock Characteristics with USB Operation ............................................. 1255
Sleep Modes AC Characteristics ....................................................................... 1255
Flash Memory Characteristics ........................................................................... 1255
GPIO Module Characteristics ............................................................................ 1256
EPI SDRAM Characteristics ............................................................................. 1256
EPI SDRAM Interface Characteristics ............................................................... 1256
EPI Host-Bus 8 and Host-Bus 16 Interface Characteristics ................................. 1258
EPI General-Purpose Interface Characteristics .................................................. 1260
ADC Characteristics ......................................................................................... 1262
ADC Module External Reference Characteristics ............................................... 1263
ADC Module Internal Reference Characteristics ................................................ 1263
SSI Characteristics .......................................................................................... 1263
I2C Characteristics ........................................................................................... 1265
I2S Master Clock (Receive and Transmit) .......................................................... 1266
I2S Slave Clock (Receive and Transmit) ............................................................ 1266
I2S Master Mode .............................................................................................. 1266
I2S Slave Mode ................................................................................................ 1267
USB Controller Characteristics ......................................................................... 1268
Analog Comparator Characteristics ................................................................... 1268
Analog Comparator Voltage Reference Characteristics ...................................... 1268
Nominal Power Consumption ........................................................................... 1268
Detailed Current Specifications ......................................................................... 1269
18
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
List of Registers
The Cortex-M3 Processor ............................................................................................................. 75
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:
Cortex General-Purpose Register 0 (R0) ........................................................................... 82
Cortex General-Purpose Register 1 (R1) ........................................................................... 82
Cortex General-Purpose Register 2 (R2) ........................................................................... 82
Cortex General-Purpose Register 3 (R3) ........................................................................... 82
Cortex General-Purpose Register 4 (R4) ........................................................................... 82
Cortex General-Purpose Register 5 (R5) ........................................................................... 82
Cortex General-Purpose Register 6 (R6) ........................................................................... 82
Cortex General-Purpose Register 7 (R7) ........................................................................... 82
Cortex General-Purpose Register 8 (R8) ........................................................................... 82
Cortex General-Purpose Register 9 (R9) ........................................................................... 82
Cortex General-Purpose Register 10 (R10) ....................................................................... 82
Cortex General-Purpose Register 11 (R11) ........................................................................ 82
Cortex General-Purpose Register 12 (R12) ....................................................................... 82
Stack Pointer (SP) ........................................................................................................... 83
Link Register (LR) ............................................................................................................ 84
Program Counter (PC) ..................................................................................................... 85
Program Status Register (PSR) ........................................................................................ 86
Priority Mask Register (PRIMASK) .................................................................................... 90
Fault Mask Register (FAULTMASK) .................................................................................. 91
Base Priority Mask Register (BASEPRI) ............................................................................ 92
Control Register (CONTROL) ........................................................................................... 93
Cortex-M3 Peripherals ................................................................................................................. 118
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:
SysTick Control and Status Register (STCTRL), offset 0x010 ........................................... 129
SysTick Reload Value Register (STRELOAD), offset 0x014 .............................................. 131
SysTick Current Value Register (STCURRENT), offset 0x018 ........................................... 132
Interrupt 0-31 Set Enable (EN0), offset 0x100 .................................................................. 133
Interrupt 32-54 Set Enable (EN1), offset 0x104 ................................................................ 134
Interrupt 0-31 Clear Enable (DIS0), offset 0x180 .............................................................. 135
Interrupt 32-54 Clear Enable (DIS1), offset 0x184 ............................................................ 136
Interrupt 0-31 Set Pending (PEND0), offset 0x200 ........................................................... 137
Interrupt 32-54 Set Pending (PEND1), offset 0x204 ......................................................... 138
Interrupt 0-31 Clear Pending (UNPEND0), offset 0x280 ................................................... 139
Interrupt 32-54 Clear Pending (UNPEND1), offset 0x284 .................................................. 140
Interrupt 0-31 Active Bit (ACTIVE0), offset 0x300 ............................................................. 141
Interrupt 32-54 Active Bit (ACTIVE1), offset 0x304 ........................................................... 142
Interrupt 0-3 Priority (PRI0), offset 0x400 ......................................................................... 143
Interrupt 4-7 Priority (PRI1), offset 0x404 ......................................................................... 143
Interrupt 8-11 Priority (PRI2), offset 0x408 ....................................................................... 143
Interrupt 12-15 Priority (PRI3), offset 0x40C .................................................................... 143
Interrupt 16-19 Priority (PRI4), offset 0x410 ..................................................................... 143
Interrupt 20-23 Priority (PRI5), offset 0x414 ..................................................................... 143
Interrupt 24-27 Priority (PRI6), offset 0x418 ..................................................................... 143
Interrupt 28-31 Priority (PRI7), offset 0x41C .................................................................... 143
Interrupt 32-35 Priority (PRI8), offset 0x420 ..................................................................... 143
July 03, 2014
19
Texas Instruments-Production Data
Table of Contents
Register 23:
Register 24:
Register 25:
Register 26:
Register 27:
Register 28:
Register 29:
Register 30:
Register 31:
Register 32:
Register 33:
Register 34:
Register 35:
Register 36:
Register 37:
Register 38:
Register 39:
Register 40:
Register 41:
Register 42:
Register 43:
Register 44:
Register 45:
Register 46:
Register 47:
Register 48:
Register 49:
Register 50:
Register 51:
Register 52:
Register 53:
Register 54:
Interrupt 36-39 Priority (PRI9), offset 0x424 ..................................................................... 143
Interrupt 40-43 Priority (PRI10), offset 0x428 ................................................................... 143
Interrupt 44-47 Priority (PRI11), offset 0x42C ................................................................... 143
Interrupt 48-51 Priority (PRI12), offset 0x430 ................................................................... 143
Interrupt 52-54 Priority (PRI13), offset 0x434 ................................................................... 143
Software Trigger Interrupt (SWTRIG), offset 0xF00 .......................................................... 145
Auxiliary Control (ACTLR), offset 0x008 .......................................................................... 146
CPU ID Base (CPUID), offset 0xD00 ............................................................................... 148
Interrupt Control and State (INTCTRL), offset 0xD04 ........................................................ 149
Vector Table Offset (VTABLE), offset 0xD08 .................................................................... 152
Application Interrupt and Reset Control (APINT), offset 0xD0C ......................................... 153
System Control (SYSCTRL), offset 0xD10 ....................................................................... 155
Configuration and Control (CFGCTRL), offset 0xD14 ....................................................... 157
System Handler Priority 1 (SYSPRI1), offset 0xD18 ......................................................... 159
System Handler Priority 2 (SYSPRI2), offset 0xD1C ........................................................ 160
System Handler Priority 3 (SYSPRI3), offset 0xD20 ......................................................... 161
System Handler Control and State (SYSHNDCTRL), offset 0xD24 .................................... 162
Configurable Fault Status (FAULTSTAT), offset 0xD28 ..................................................... 166
Hard Fault Status (HFAULTSTAT), offset 0xD2C .............................................................. 172
Memory Management Fault Address (MMADDR), offset 0xD34 ........................................ 173
Bus Fault Address (FAULTADDR), offset 0xD38 .............................................................. 174
MPU Type (MPUTYPE), offset 0xD90 ............................................................................. 175
MPU Control (MPUCTRL), offset 0xD94 .......................................................................... 176
MPU Region Number (MPUNUMBER), offset 0xD98 ....................................................... 178
MPU Region Base Address (MPUBASE), offset 0xD9C ................................................... 179
MPU Region Base Address Alias 1 (MPUBASE1), offset 0xDA4 ....................................... 179
MPU Region Base Address Alias 2 (MPUBASE2), offset 0xDAC ...................................... 179
MPU Region Base Address Alias 3 (MPUBASE3), offset 0xDB4 ....................................... 179
MPU Region Attribute and Size (MPUATTR), offset 0xDA0 ............................................... 181
MPU Region Attribute and Size Alias 1 (MPUATTR1), offset 0xDA8 .................................. 181
MPU Region Attribute and Size Alias 2 (MPUATTR2), offset 0xDB0 .................................. 181
MPU Region Attribute and Size Alias 3 (MPUATTR3), offset 0xDB8 .................................. 181
System Control ............................................................................................................................ 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:
Device Identification 0 (DID0), offset 0x000 ..................................................................... 214
Brown-Out Reset Control (PBORCTL), offset 0x030 ........................................................ 216
Raw Interrupt Status (RIS), offset 0x050 .......................................................................... 217
Interrupt Mask Control (IMC), offset 0x054 ...................................................................... 219
Masked Interrupt Status and Clear (MISC), offset 0x058 .................................................. 221
Reset Cause (RESC), offset 0x05C ................................................................................ 223
Run-Mode Clock Configuration (RCC), offset 0x060 ......................................................... 225
XTAL to PLL Translation (PLLCFG), offset 0x064 ............................................................. 230
GPIO High-Performance Bus Control (GPIOHBCTL), offset 0x06C ................................... 231
Run-Mode Clock Configuration 2 (RCC2), offset 0x070 .................................................... 233
Main Oscillator Control (MOSCCTL), offset 0x07C ........................................................... 236
Deep Sleep Clock Configuration (DSLPCLKCFG), offset 0x144 ........................................ 237
Precision Internal Oscillator Calibration (PIOSCCAL), offset 0x150 ................................... 239
I2S MCLK Configuration (I2SMCLKCFG), offset 0x170 ..................................................... 240
Device Identification 1 (DID1), offset 0x004 ..................................................................... 242
20
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 16:
Register 17:
Register 18:
Register 19:
Register 20:
Register 21:
Register 22:
Register 23:
Register 24:
Register 25:
Register 26:
Register 27:
Register 28:
Register 29:
Register 30:
Register 31:
Register 32:
Register 33:
Register 34:
Register 35:
Register 36:
Register 37:
Register 38:
Device Capabilities 0 (DC0), offset 0x008 ........................................................................ 244
Device Capabilities 1 (DC1), offset 0x010 ........................................................................ 245
Device Capabilities 2 (DC2), offset 0x014 ........................................................................ 248
Device Capabilities 3 (DC3), offset 0x018 ........................................................................ 250
Device Capabilities 4 (DC4), offset 0x01C ....................................................................... 253
Device Capabilities 5 (DC5), offset 0x020 ........................................................................ 255
Device Capabilities 6 (DC6), offset 0x024 ........................................................................ 257
Device Capabilities 7 (DC7), offset 0x028 ........................................................................ 258
Device Capabilities 8 ADC Channels (DC8), offset 0x02C ................................................ 262
Device Capabilities 9 ADC Digital Comparators (DC9), offset 0x190 ................................. 265
Non-Volatile Memory Information (NVMSTAT), offset 0x1A0 ............................................. 267
Run Mode Clock Gating Control Register 0 (RCGC0), offset 0x100 ................................... 268
Sleep Mode Clock Gating Control Register 0 (SCGC0), offset 0x110 ................................. 271
Deep Sleep Mode Clock Gating Control Register 0 (DCGC0), offset 0x120 ....................... 274
Run Mode Clock Gating Control Register 1 (RCGC1), offset 0x104 ................................... 276
Sleep Mode Clock Gating Control Register 1 (SCGC1), offset 0x114 ................................. 280
Deep-Sleep Mode Clock Gating Control Register 1 (DCGC1), offset 0x124 ....................... 284
Run Mode Clock Gating Control Register 2 (RCGC2), offset 0x108 ................................... 288
Sleep Mode Clock Gating Control Register 2 (SCGC2), offset 0x118 ................................. 290
Deep Sleep Mode Clock Gating Control Register 2 (DCGC2), offset 0x128 ....................... 292
Software Reset Control 0 (SRCR0), offset 0x040 ............................................................. 294
Software Reset Control 1 (SRCR1), offset 0x044 ............................................................. 296
Software Reset Control 2 (SRCR2), offset 0x048 ............................................................. 299
Internal Memory ........................................................................................................................... 301
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:
Flash Memory Address (FMA), offset 0x000 .................................................................... 311
Flash Memory Data (FMD), offset 0x004 ......................................................................... 312
Flash Memory Control (FMC), offset 0x008 ..................................................................... 313
Flash Controller Raw Interrupt Status (FCRIS), offset 0x00C ............................................ 316
Flash Controller Interrupt Mask (FCIM), offset 0x010 ........................................................ 317
Flash Controller Masked Interrupt Status and Clear (FCMISC), offset 0x014 ..................... 318
Flash Memory Control 2 (FMC2), offset 0x020 ................................................................. 319
Flash Write Buffer Valid (FWBVAL), offset 0x030 ............................................................. 320
Flash Control (FCTL), offset 0x0F8 ................................................................................. 321
Flash Write Buffer n (FWBn), offset 0x100 - 0x17C .......................................................... 322
ROM Control (RMCTL), offset 0x0F0 .............................................................................. 323
Flash Memory Protection Read Enable 0 (FMPRE0), offset 0x130 and 0x200 ................... 324
Flash Memory Protection Program Enable 0 (FMPPE0), offset 0x134 and 0x400 ............... 325
Boot Configuration (BOOTCFG), offset 0x1D0 ................................................................. 326
User Register 0 (USER_REG0), offset 0x1E0 .................................................................. 328
User Register 1 (USER_REG1), offset 0x1E4 .................................................................. 329
User Register 2 (USER_REG2), offset 0x1E8 .................................................................. 330
User Register 3 (USER_REG3), offset 0x1EC ................................................................. 331
Flash Memory Protection Read Enable 1 (FMPRE1), offset 0x204 .................................... 332
Flash Memory Protection Read Enable 2 (FMPRE2), offset 0x208 .................................... 333
Flash Memory Protection Read Enable 3 (FMPRE3), offset 0x20C ................................... 334
Flash Memory Protection Program Enable 1 (FMPPE1), offset 0x404 ............................... 335
Flash Memory Protection Program Enable 2 (FMPPE2), offset 0x408 ............................... 336
Flash Memory Protection Program Enable 3 (FMPPE3), offset 0x40C ............................... 337
July 03, 2014
21
Texas Instruments-Production Data
Table of Contents
Micro Direct Memory Access (μDMA) ........................................................................................ 338
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:
DMA Channel Source Address End Pointer (DMASRCENDP), offset 0x000 ...................... 362
DMA Channel Destination Address End Pointer (DMADSTENDP), offset 0x004 ................ 363
DMA Channel Control Word (DMACHCTL), offset 0x008 .................................................. 364
DMA Status (DMASTAT), offset 0x000 ............................................................................ 369
DMA Configuration (DMACFG), offset 0x004 ................................................................... 371
DMA Channel Control Base Pointer (DMACTLBASE), offset 0x008 .................................. 372
DMA Alternate Channel Control Base Pointer (DMAALTBASE), offset 0x00C .................... 373
DMA Channel Wait-on-Request Status (DMAWAITSTAT), offset 0x010 ............................. 374
DMA Channel Software Request (DMASWREQ), offset 0x014 ......................................... 375
DMA Channel Useburst Set (DMAUSEBURSTSET), offset 0x018 .................................... 376
DMA Channel Useburst Clear (DMAUSEBURSTCLR), offset 0x01C ................................. 377
DMA Channel Request Mask Set (DMAREQMASKSET), offset 0x020 .............................. 378
DMA Channel Request Mask Clear (DMAREQMASKCLR), offset 0x024 ........................... 379
DMA Channel Enable Set (DMAENASET), offset 0x028 ................................................... 380
DMA Channel Enable Clear (DMAENACLR), offset 0x02C ............................................... 381
DMA Channel Primary Alternate Set (DMAALTSET), offset 0x030 .................................... 382
DMA Channel Primary Alternate Clear (DMAALTCLR), offset 0x034 ................................. 383
DMA Channel Priority Set (DMAPRIOSET), offset 0x038 ................................................. 384
DMA Channel Priority Clear (DMAPRIOCLR), offset 0x03C .............................................. 385
DMA Bus Error Clear (DMAERRCLR), offset 0x04C ........................................................ 386
DMA Channel Assignment (DMACHASGN), offset 0x500 ................................................. 387
DMA Peripheral Identification 0 (DMAPeriphID0), offset 0xFE0 ......................................... 388
DMA Peripheral Identification 1 (DMAPeriphID1), offset 0xFE4 ......................................... 389
DMA Peripheral Identification 2 (DMAPeriphID2), offset 0xFE8 ......................................... 390
DMA Peripheral Identification 3 (DMAPeriphID3), offset 0xFEC ........................................ 391
DMA Peripheral Identification 4 (DMAPeriphID4), offset 0xFD0 ......................................... 392
DMA PrimeCell Identification 0 (DMAPCellID0), offset 0xFF0 ........................................... 393
DMA PrimeCell Identification 1 (DMAPCellID1), offset 0xFF4 ........................................... 394
DMA PrimeCell Identification 2 (DMAPCellID2), offset 0xFF8 ........................................... 395
DMA PrimeCell Identification 3 (DMAPCellID3), offset 0xFFC ........................................... 396
General-Purpose Input/Outputs (GPIOs) ................................................................................... 397
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:
GPIO Data (GPIODATA), offset 0x000 ............................................................................ 411
GPIO Direction (GPIODIR), offset 0x400 ......................................................................... 412
GPIO Interrupt Sense (GPIOIS), offset 0x404 .................................................................. 413
GPIO Interrupt Both Edges (GPIOIBE), offset 0x408 ........................................................ 414
GPIO Interrupt Event (GPIOIEV), offset 0x40C ................................................................ 415
GPIO Interrupt Mask (GPIOIM), offset 0x410 ................................................................... 416
GPIO Raw Interrupt Status (GPIORIS), offset 0x414 ........................................................ 417
GPIO Masked Interrupt Status (GPIOMIS), offset 0x418 ................................................... 418
GPIO Interrupt Clear (GPIOICR), offset 0x41C ................................................................ 420
GPIO Alternate Function Select (GPIOAFSEL), offset 0x420 ............................................ 421
GPIO 2-mA Drive Select (GPIODR2R), offset 0x500 ........................................................ 423
GPIO 4-mA Drive Select (GPIODR4R), offset 0x504 ........................................................ 424
GPIO 8-mA Drive Select (GPIODR8R), offset 0x508 ........................................................ 425
GPIO Open Drain Select (GPIOODR), offset 0x50C ......................................................... 426
GPIO Pull-Up Select (GPIOPUR), offset 0x510 ................................................................ 427
GPIO Pull-Down Select (GPIOPDR), offset 0x514 ........................................................... 429
22
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
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:
GPIO Slew Rate Control Select (GPIOSLR), offset 0x518 ................................................ 431
GPIO Digital Enable (GPIODEN), offset 0x51C ................................................................ 432
GPIO Lock (GPIOLOCK), offset 0x520 ............................................................................ 434
GPIO Commit (GPIOCR), offset 0x524 ............................................................................ 435
GPIO Analog Mode Select (GPIOAMSEL), offset 0x528 ................................................... 437
GPIO Port Control (GPIOPCTL), offset 0x52C ................................................................. 439
GPIO Peripheral Identification 4 (GPIOPeriphID4), offset 0xFD0 ....................................... 441
GPIO Peripheral Identification 5 (GPIOPeriphID5), offset 0xFD4 ....................................... 442
GPIO Peripheral Identification 6 (GPIOPeriphID6), offset 0xFD8 ....................................... 443
GPIO Peripheral Identification 7 (GPIOPeriphID7), offset 0xFDC ...................................... 444
GPIO Peripheral Identification 0 (GPIOPeriphID0), offset 0xFE0 ....................................... 445
GPIO Peripheral Identification 1 (GPIOPeriphID1), offset 0xFE4 ....................................... 446
GPIO Peripheral Identification 2 (GPIOPeriphID2), offset 0xFE8 ....................................... 447
GPIO Peripheral Identification 3 (GPIOPeriphID3), offset 0xFEC ...................................... 448
GPIO PrimeCell Identification 0 (GPIOPCellID0), offset 0xFF0 .......................................... 449
GPIO PrimeCell Identification 1 (GPIOPCellID1), offset 0xFF4 .......................................... 450
GPIO PrimeCell Identification 2 (GPIOPCellID2), offset 0xFF8 .......................................... 451
GPIO PrimeCell Identification 3 (GPIOPCellID3), offset 0xFFC ......................................... 452
External Peripheral Interface (EPI) ............................................................................................. 453
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:
EPI Configuration (EPICFG), offset 0x000 ....................................................................... 485
EPI Main Baud Rate (EPIBAUD), offset 0x004 ................................................................. 486
EPI SDRAM Configuration (EPISDRAMCFG), offset 0x010 .............................................. 488
EPI Host-Bus 8 Configuration (EPIHB8CFG), offset 0x010 ............................................... 490
EPI Host-Bus 16 Configuration (EPIHB16CFG), offset 0x010 ........................................... 493
EPI General-Purpose Configuration (EPIGPCFG), offset 0x010 ........................................ 497
EPI Host-Bus 8 Configuration 2 (EPIHB8CFG2), offset 0x014 .......................................... 502
EPI Host-Bus 16 Configuration 2 (EPIHB16CFG2), offset 0x014 ....................................... 504
EPI General-Purpose Configuration 2 (EPIGPCFG2), offset 0x014 ................................... 506
EPI Address Map (EPIADDRMAP), offset 0x01C ............................................................. 507
EPI Read Size 0 (EPIRSIZE0), offset 0x020 .................................................................... 509
EPI Read Size 1 (EPIRSIZE1), offset 0x030 .................................................................... 509
EPI Read Address 0 (EPIRADDR0), offset 0x024 ............................................................ 510
EPI Read Address 1 (EPIRADDR1), offset 0x034 ............................................................ 510
EPI Non-Blocking Read Data 0 (EPIRPSTD0), offset 0x028 ............................................. 511
EPI Non-Blocking Read Data 1 (EPIRPSTD1), offset 0x038 ............................................. 511
EPI Status (EPISTAT), offset 0x060 ................................................................................ 513
EPI Read FIFO Count (EPIRFIFOCNT), offset 0x06C ...................................................... 515
EPI Read FIFO (EPIREADFIFO), offset 0x070 ................................................................ 516
EPI Read FIFO Alias 1 (EPIREADFIFO1), offset 0x074 .................................................... 516
EPI Read FIFO Alias 2 (EPIREADFIFO2), offset 0x078 .................................................... 516
EPI Read FIFO Alias 3 (EPIREADFIFO3), offset 0x07C ................................................... 516
EPI Read FIFO Alias 4 (EPIREADFIFO4), offset 0x080 .................................................... 516
EPI Read FIFO Alias 5 (EPIREADFIFO5), offset 0x084 .................................................... 516
EPI Read FIFO Alias 6 (EPIREADFIFO6), offset 0x088 .................................................... 516
EPI Read FIFO Alias 7 (EPIREADFIFO7), offset 0x08C ................................................... 516
EPI FIFO Level Selects (EPIFIFOLVL), offset 0x200 ........................................................ 517
EPI Write FIFO Count (EPIWFIFOCNT), offset 0x204 ...................................................... 519
EPI Interrupt Mask (EPIIM), offset 0x210 ......................................................................... 520
July 03, 2014
23
Texas Instruments-Production Data
Table of Contents
Register 30:
Register 31:
Register 32:
EPI Raw Interrupt Status (EPIRIS), offset 0x214 .............................................................. 521
EPI Masked Interrupt Status (EPIMIS), offset 0x218 ........................................................ 523
EPI Error and Interrupt Status and Clear (EPIEISC), offset 0x21C .................................... 524
General-Purpose Timers ............................................................................................................. 526
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:
GPTM Configuration (GPTMCFG), offset 0x000 .............................................................. 543
GPTM Timer A Mode (GPTMTAMR), offset 0x004 ........................................................... 544
GPTM Timer B Mode (GPTMTBMR), offset 0x008 ........................................................... 546
GPTM Control (GPTMCTL), offset 0x00C ........................................................................ 548
GPTM Interrupt Mask (GPTMIMR), offset 0x018 .............................................................. 551
GPTM Raw Interrupt Status (GPTMRIS), offset 0x01C ..................................................... 553
GPTM Masked Interrupt Status (GPTMMIS), offset 0x020 ................................................ 556
GPTM Interrupt Clear (GPTMICR), offset 0x024 .............................................................. 559
GPTM Timer A Interval Load (GPTMTAILR), offset 0x028 ................................................ 561
GPTM Timer B Interval Load (GPTMTBILR), offset 0x02C ................................................ 562
GPTM Timer A Match (GPTMTAMATCHR), offset 0x030 .................................................. 563
GPTM Timer B Match (GPTMTBMATCHR), offset 0x034 ................................................. 564
GPTM Timer A Prescale (GPTMTAPR), offset 0x038 ....................................................... 565
GPTM Timer B Prescale (GPTMTBPR), offset 0x03C ...................................................... 566
GPTM TimerA Prescale Match (GPTMTAPMR), offset 0x040 ........................................... 567
GPTM TimerB Prescale Match (GPTMTBPMR), offset 0x044 ........................................... 568
GPTM Timer A (GPTMTAR), offset 0x048 ....................................................................... 569
GPTM Timer B (GPTMTBR), offset 0x04C ....................................................................... 570
GPTM Timer A Value (GPTMTAV), offset 0x050 ............................................................... 571
GPTM Timer B Value (GPTMTBV), offset 0x054 .............................................................. 572
Watchdog Timers ......................................................................................................................... 573
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 ...................................................................... 577
Watchdog Value (WDTVALUE), offset 0x004 ................................................................... 578
Watchdog Control (WDTCTL), offset 0x008 ..................................................................... 579
Watchdog Interrupt Clear (WDTICR), offset 0x00C .......................................................... 581
Watchdog Raw Interrupt Status (WDTRIS), offset 0x010 .................................................. 582
Watchdog Masked Interrupt Status (WDTMIS), offset 0x014 ............................................. 583
Watchdog Test (WDTTEST), offset 0x418 ....................................................................... 584
Watchdog Lock (WDTLOCK), offset 0xC00 ..................................................................... 585
Watchdog Peripheral Identification 4 (WDTPeriphID4), offset 0xFD0 ................................. 586
Watchdog Peripheral Identification 5 (WDTPeriphID5), offset 0xFD4 ................................. 587
Watchdog Peripheral Identification 6 (WDTPeriphID6), offset 0xFD8 ................................. 588
Watchdog Peripheral Identification 7 (WDTPeriphID7), offset 0xFDC ................................ 589
Watchdog Peripheral Identification 0 (WDTPeriphID0), offset 0xFE0 ................................. 590
Watchdog Peripheral Identification 1 (WDTPeriphID1), offset 0xFE4 ................................. 591
Watchdog Peripheral Identification 2 (WDTPeriphID2), offset 0xFE8 ................................. 592
Watchdog Peripheral Identification 3 (WDTPeriphID3), offset 0xFEC ................................. 593
Watchdog PrimeCell Identification 0 (WDTPCellID0), offset 0xFF0 .................................... 594
Watchdog PrimeCell Identification 1 (WDTPCellID1), offset 0xFF4 .................................... 595
Watchdog PrimeCell Identification 2 (WDTPCellID2), offset 0xFF8 .................................... 596
Watchdog PrimeCell Identification 3 (WDTPCellID3 ), offset 0xFFC .................................. 597
Analog-to-Digital Converter (ADC) ............................................................................................. 598
Register 1:
Register 2:
ADC Active Sample Sequencer (ADCACTSS), offset 0x000 ............................................. 621
ADC Raw Interrupt Status (ADCRIS), offset 0x004 ........................................................... 622
24
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 3:
Register 4:
Register 5:
Register 6:
Register 7:
Register 8:
Register 9:
Register 10:
Register 11:
Register 12:
Register 13:
Register 14:
Register 15:
Register 16:
Register 17:
Register 18:
Register 19:
Register 20:
Register 21:
Register 22:
Register 23:
Register 24:
Register 25:
Register 26:
Register 27:
Register 28:
Register 29:
Register 30:
Register 31:
Register 32:
Register 33:
Register 34:
Register 35:
Register 36:
Register 37:
Register 38:
Register 39:
Register 40:
Register 41:
Register 42:
Register 43:
Register 44:
Register 45:
Register 46:
Register 47:
Register 48:
Register 49:
Register 50:
ADC Interrupt Mask (ADCIM), offset 0x008 ..................................................................... 624
ADC Interrupt Status and Clear (ADCISC), offset 0x00C .................................................. 626
ADC Overflow Status (ADCOSTAT), offset 0x010 ............................................................ 629
ADC Event Multiplexer Select (ADCEMUX), offset 0x014 ................................................. 631
ADC Underflow Status (ADCUSTAT), offset 0x018 ........................................................... 636
ADC Sample Sequencer Priority (ADCSSPRI), offset 0x020 ............................................. 637
ADC Sample Phase Control (ADCSPC), offset 0x024 ...................................................... 639
ADC Processor Sample Sequence Initiate (ADCPSSI), offset 0x028 ................................. 641
ADC Sample Averaging Control (ADCSAC), offset 0x030 ................................................. 643
ADC Digital Comparator Interrupt Status and Clear (ADCDCISC), offset 0x034 ................. 644
ADC Control (ADCCTL), offset 0x038 ............................................................................. 646
ADC Sample Sequence Input Multiplexer Select 0 (ADCSSMUX0), offset 0x040 ............... 647
ADC Sample Sequence Control 0 (ADCSSCTL0), offset 0x044 ........................................ 649
ADC Sample Sequence Result FIFO 0 (ADCSSFIFO0), offset 0x048 ................................ 652
ADC Sample Sequence Result FIFO 1 (ADCSSFIFO1), offset 0x068 ................................ 652
ADC Sample Sequence Result FIFO 2 (ADCSSFIFO2), offset 0x088 ................................ 652
ADC Sample Sequence Result FIFO 3 (ADCSSFIFO3), offset 0x0A8 ............................... 652
ADC Sample Sequence FIFO 0 Status (ADCSSFSTAT0), offset 0x04C ............................. 653
ADC Sample Sequence FIFO 1 Status (ADCSSFSTAT1), offset 0x06C ............................. 653
ADC Sample Sequence FIFO 2 Status (ADCSSFSTAT2), offset 0x08C ............................ 653
ADC Sample Sequence FIFO 3 Status (ADCSSFSTAT3), offset 0x0AC ............................ 653
ADC Sample Sequence 0 Operation (ADCSSOP0), offset 0x050 ...................................... 655
ADC Sample Sequence 0 Digital Comparator Select (ADCSSDC0), offset 0x054 .............. 657
ADC Sample Sequence Input Multiplexer Select 1 (ADCSSMUX1), offset 0x060 ............... 659
ADC Sample Sequence Input Multiplexer Select 2 (ADCSSMUX2), offset 0x080 ............... 659
ADC Sample Sequence Control 1 (ADCSSCTL1), offset 0x064 ........................................ 660
ADC Sample Sequence Control 2 (ADCSSCTL2), offset 0x084 ........................................ 660
ADC Sample Sequence 1 Operation (ADCSSOP1), offset 0x070 ...................................... 662
ADC Sample Sequence 2 Operation (ADCSSOP2), offset 0x090 ..................................... 662
ADC Sample Sequence 1 Digital Comparator Select (ADCSSDC1), offset 0x074 .............. 663
ADC Sample Sequence 2 Digital Comparator Select (ADCSSDC2), offset 0x094 .............. 663
ADC Sample Sequence Input Multiplexer Select 3 (ADCSSMUX3), offset 0x0A0 ............... 665
ADC Sample Sequence Control 3 (ADCSSCTL3), offset 0x0A4 ........................................ 666
ADC Sample Sequence 3 Operation (ADCSSOP3), offset 0x0B0 ..................................... 667
ADC Sample Sequence 3 Digital Comparator Select (ADCSSDC3), offset 0x0B4 .............. 668
ADC Digital Comparator Reset Initial Conditions (ADCDCRIC), offset 0xD00 ..................... 669
ADC Digital Comparator Control 0 (ADCDCCTL0), offset 0xE00 ....................................... 674
ADC Digital Comparator Control 1 (ADCDCCTL1), offset 0xE04 ....................................... 674
ADC Digital Comparator Control 2 (ADCDCCTL2), offset 0xE08 ....................................... 674
ADC Digital Comparator Control 3 (ADCDCCTL3), offset 0xE0C ...................................... 674
ADC Digital Comparator Control 4 (ADCDCCTL4), offset 0xE10 ....................................... 674
ADC Digital Comparator Control 5 (ADCDCCTL5), offset 0xE14 ....................................... 674
ADC Digital Comparator Control 6 (ADCDCCTL6), offset 0xE18 ....................................... 674
ADC Digital Comparator Control 7 (ADCDCCTL7), offset 0xE1C ...................................... 674
ADC Digital Comparator Range 0 (ADCDCCMP0), offset 0xE40 ....................................... 677
ADC Digital Comparator Range 1 (ADCDCCMP1), offset 0xE44 ....................................... 677
ADC Digital Comparator Range 2 (ADCDCCMP2), offset 0xE48 ....................................... 677
ADC Digital Comparator Range 3 (ADCDCCMP3), offset 0xE4C ...................................... 677
July 03, 2014
25
Texas Instruments-Production Data
Table of Contents
Register 51:
Register 52:
Register 53:
Register 54:
ADC Digital Comparator Range 4 (ADCDCCMP4), offset 0xE50 .......................................
ADC Digital Comparator Range 5 (ADCDCCMP5), offset 0xE54 .......................................
ADC Digital Comparator Range 6 (ADCDCCMP6), offset 0xE58 .......................................
ADC Digital Comparator Range 7 (ADCDCCMP7), offset 0xE5C ......................................
677
677
677
677
Universal Asynchronous Receivers/Transmitters (UARTs) ..................................................... 678
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:
UART Data (UARTDR), offset 0x000 ............................................................................... 693
UART Receive Status/Error Clear (UARTRSR/UARTECR), offset 0x004 ........................... 695
UART Flag (UARTFR), offset 0x018 ................................................................................ 698
UART IrDA Low-Power Register (UARTILPR), offset 0x020 ............................................. 701
UART Integer Baud-Rate Divisor (UARTIBRD), offset 0x024 ............................................ 702
UART Fractional Baud-Rate Divisor (UARTFBRD), offset 0x028 ....................................... 703
UART Line Control (UARTLCRH), offset 0x02C ............................................................... 704
UART Control (UARTCTL), offset 0x030 ......................................................................... 706
UART Interrupt FIFO Level Select (UARTIFLS), offset 0x034 ........................................... 710
UART Interrupt Mask (UARTIM), offset 0x038 ................................................................. 712
UART Raw Interrupt Status (UARTRIS), offset 0x03C ...................................................... 716
UART Masked Interrupt Status (UARTMIS), offset 0x040 ................................................. 720
UART Interrupt Clear (UARTICR), offset 0x044 ............................................................... 724
UART DMA Control (UARTDMACTL), offset 0x048 .......................................................... 726
UART LIN Control (UARTLCTL), offset 0x090 ................................................................. 727
UART LIN Snap Shot (UARTLSS), offset 0x094 ............................................................... 728
UART LIN Timer (UARTLTIM), offset 0x098 ..................................................................... 729
UART Peripheral Identification 4 (UARTPeriphID4), offset 0xFD0 ..................................... 730
UART Peripheral Identification 5 (UARTPeriphID5), offset 0xFD4 ..................................... 731
UART Peripheral Identification 6 (UARTPeriphID6), offset 0xFD8 ..................................... 732
UART Peripheral Identification 7 (UARTPeriphID7), offset 0xFDC ..................................... 733
UART Peripheral Identification 0 (UARTPeriphID0), offset 0xFE0 ...................................... 734
UART Peripheral Identification 1 (UARTPeriphID1), offset 0xFE4 ...................................... 735
UART Peripheral Identification 2 (UARTPeriphID2), offset 0xFE8 ...................................... 736
UART Peripheral Identification 3 (UARTPeriphID3), offset 0xFEC ..................................... 737
UART PrimeCell Identification 0 (UARTPCellID0), offset 0xFF0 ........................................ 738
UART PrimeCell Identification 1 (UARTPCellID1), offset 0xFF4 ........................................ 739
UART PrimeCell Identification 2 (UARTPCellID2), offset 0xFF8 ........................................ 740
UART PrimeCell Identification 3 (UARTPCellID3), offset 0xFFC ........................................ 741
Synchronous Serial Interface (SSI) ............................................................................................ 742
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:
SSI Control 0 (SSICR0), offset 0x000 .............................................................................. 757
SSI Control 1 (SSICR1), offset 0x004 .............................................................................. 759
SSI Data (SSIDR), offset 0x008 ...................................................................................... 761
SSI Status (SSISR), offset 0x00C ................................................................................... 762
SSI Clock Prescale (SSICPSR), offset 0x010 .................................................................. 764
SSI Interrupt Mask (SSIIM), offset 0x014 ......................................................................... 765
SSI Raw Interrupt Status (SSIRIS), offset 0x018 .............................................................. 766
SSI Masked Interrupt Status (SSIMIS), offset 0x01C ........................................................ 768
SSI Interrupt Clear (SSIICR), offset 0x020 ....................................................................... 770
SSI DMA Control (SSIDMACTL), offset 0x024 ................................................................. 771
SSI Peripheral Identification 4 (SSIPeriphID4), offset 0xFD0 ............................................. 772
SSI Peripheral Identification 5 (SSIPeriphID5), offset 0xFD4 ............................................. 773
SSI Peripheral Identification 6 (SSIPeriphID6), offset 0xFD8 ............................................. 774
26
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 14:
Register 15:
Register 16:
Register 17:
Register 18:
Register 19:
Register 20:
Register 21:
Register 22:
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 ...............................................
775
776
777
778
779
780
781
782
783
Inter-Integrated Circuit (I2C) Interface ........................................................................................ 784
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:
I2C Master Slave Address (I2CMSA), offset 0x000 ........................................................... 801
I2C Master Control/Status (I2CMCS), offset 0x004 ........................................................... 802
I2C Master Data (I2CMDR), offset 0x008 ......................................................................... 807
I2C Master Timer Period (I2CMTPR), offset 0x00C ........................................................... 808
I2C Master Interrupt Mask (I2CMIMR), offset 0x010 ......................................................... 809
I2C Master Raw Interrupt Status (I2CMRIS), offset 0x014 ................................................. 810
I2C Master Masked Interrupt Status (I2CMMIS), offset 0x018 ........................................... 811
I2C Master Interrupt Clear (I2CMICR), offset 0x01C ......................................................... 812
I2C Master Configuration (I2CMCR), offset 0x020 ............................................................ 813
I2C Slave Own Address (I2CSOAR), offset 0x800 ............................................................ 814
I2C Slave Control/Status (I2CSCSR), offset 0x804 ........................................................... 815
I2C Slave Data (I2CSDR), offset 0x808 ........................................................................... 817
I2C Slave Interrupt Mask (I2CSIMR), offset 0x80C ........................................................... 818
I2C Slave Raw Interrupt Status (I2CSRIS), offset 0x810 ................................................... 819
I2C Slave Masked Interrupt Status (I2CSMIS), offset 0x814 .............................................. 820
I2C Slave Interrupt Clear (I2CSICR), offset 0x818 ............................................................ 821
Inter-Integrated Circuit Sound (I2S) Interface ............................................................................ 822
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:
I2S Transmit FIFO Data (I2STXFIFO), offset 0x000 .......................................................... 835
I2S Transmit FIFO Configuration (I2STXFIFOCFG), offset 0x004 ...................................... 836
I2S Transmit Module Configuration (I2STXCFG), offset 0x008 .......................................... 837
I2S Transmit FIFO Limit (I2STXLIMIT), offset 0x00C ........................................................ 839
I2S Transmit Interrupt Status and Mask (I2STXISM), offset 0x010 ..................................... 840
I2S Transmit FIFO Level (I2STXLEV), offset 0x018 .......................................................... 841
I2S Receive FIFO Data (I2SRXFIFO), offset 0x800 .......................................................... 842
I2S Receive FIFO Configuration (I2SRXFIFOCFG), offset 0x804 ...................................... 843
I2S Receive Module Configuration (I2SRXCFG), offset 0x808 ........................................... 844
I2S Receive FIFO Limit (I2SRXLIMIT), offset 0x80C ......................................................... 847
I2S Receive Interrupt Status and Mask (I2SRXISM), offset 0x810 ..................................... 848
I2S Receive FIFO Level (I2SRXLEV), offset 0x818 ........................................................... 849
I2S Module Configuration (I2SCFG), offset 0xC00 ............................................................ 850
I2S Interrupt Mask (I2SIM), offset 0xC10 ......................................................................... 852
I2S Raw Interrupt Status (I2SRIS), offset 0xC14 ............................................................... 854
I2S Masked Interrupt Status (I2SMIS), offset 0xC18 ......................................................... 856
I2S Interrupt Clear (I2SIC), offset 0xC1C ......................................................................... 858
Controller Area Network (CAN) Module ..................................................................................... 859
Register 1:
CAN Control (CANCTL), offset 0x000 ............................................................................. 881
July 03, 2014
27
Texas Instruments-Production Data
Table of Contents
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
Register 7:
Register 8:
Register 9:
Register 10:
Register 11:
Register 12:
Register 13:
Register 14:
Register 15:
Register 16:
Register 17:
Register 18:
Register 19:
Register 20:
Register 21:
Register 22:
Register 23:
Register 24:
Register 25:
Register 26:
Register 27:
Register 28:
Register 29:
Register 30:
Register 31:
Register 32:
Register 33:
Register 34:
Register 35:
Register 36:
Register 37:
CAN Status (CANSTS), offset 0x004 ............................................................................... 883
CAN Error Counter (CANERR), offset 0x008 ................................................................... 886
CAN Bit Timing (CANBIT), offset 0x00C .......................................................................... 887
CAN Interrupt (CANINT), offset 0x010 ............................................................................. 888
CAN Test (CANTST), offset 0x014 .................................................................................. 889
CAN Baud Rate Prescaler Extension (CANBRPE), offset 0x018 ....................................... 891
CAN IF1 Command Request (CANIF1CRQ), offset 0x020 ................................................ 892
CAN IF2 Command Request (CANIF2CRQ), offset 0x080 ................................................ 892
CAN IF1 Command Mask (CANIF1CMSK), offset 0x024 .................................................. 893
CAN IF2 Command Mask (CANIF2CMSK), offset 0x084 .................................................. 893
CAN IF1 Mask 1 (CANIF1MSK1), offset 0x028 ................................................................ 896
CAN IF2 Mask 1 (CANIF2MSK1), offset 0x088 ................................................................ 896
CAN IF1 Mask 2 (CANIF1MSK2), offset 0x02C ................................................................ 897
CAN IF2 Mask 2 (CANIF2MSK2), offset 0x08C ................................................................ 897
CAN IF1 Arbitration 1 (CANIF1ARB1), offset 0x030 ......................................................... 899
CAN IF2 Arbitration 1 (CANIF2ARB1), offset 0x090 ......................................................... 899
CAN IF1 Arbitration 2 (CANIF1ARB2), offset 0x034 ......................................................... 900
CAN IF2 Arbitration 2 (CANIF2ARB2), offset 0x094 ......................................................... 900
CAN IF1 Message Control (CANIF1MCTL), offset 0x038 .................................................. 902
CAN IF2 Message Control (CANIF2MCTL), offset 0x098 .................................................. 902
CAN IF1 Data A1 (CANIF1DA1), offset 0x03C ................................................................. 905
CAN IF1 Data A2 (CANIF1DA2), offset 0x040 ................................................................. 905
CAN IF1 Data B1 (CANIF1DB1), offset 0x044 ................................................................. 905
CAN IF1 Data B2 (CANIF1DB2), offset 0x048 ................................................................. 905
CAN IF2 Data A1 (CANIF2DA1), offset 0x09C ................................................................. 905
CAN IF2 Data A2 (CANIF2DA2), offset 0x0A0 ................................................................. 905
CAN IF2 Data B1 (CANIF2DB1), offset 0x0A4 ................................................................. 905
CAN IF2 Data B2 (CANIF2DB2), offset 0x0A8 ................................................................. 905
CAN Transmission Request 1 (CANTXRQ1), offset 0x100 ................................................ 906
CAN Transmission Request 2 (CANTXRQ2), offset 0x104 ................................................ 906
CAN New Data 1 (CANNWDA1), offset 0x120 ................................................................. 907
CAN New Data 2 (CANNWDA2), offset 0x124 ................................................................. 907
CAN Message 1 Interrupt Pending (CANMSG1INT), offset 0x140 ..................................... 908
CAN Message 2 Interrupt Pending (CANMSG2INT), offset 0x144 ..................................... 908
CAN Message 1 Valid (CANMSG1VAL), offset 0x160 ....................................................... 909
CAN Message 2 Valid (CANMSG2VAL), offset 0x164 ....................................................... 909
Universal Serial Bus (USB) Controller ....................................................................................... 910
Register 1:
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
Register 7:
Register 8:
Register 9:
Register 10:
Register 11:
USB Device Functional Address (USBFADDR), offset 0x000 ............................................ 938
USB Power (USBPOWER), offset 0x001 ......................................................................... 939
USB Transmit Interrupt Status (USBTXIS), offset 0x002 ................................................... 942
USB Receive Interrupt Status (USBRXIS), offset 0x004 ................................................... 944
USB Transmit Interrupt Enable (USBTXIE), offset 0x006 .................................................. 946
USB Receive Interrupt Enable (USBRXIE), offset 0x008 .................................................. 948
USB General Interrupt Status (USBIS), offset 0x00A ........................................................ 950
USB Interrupt Enable (USBIE), offset 0x00B .................................................................... 953
USB Frame Value (USBFRAME), offset 0x00C ................................................................ 956
USB Endpoint Index (USBEPIDX), offset 0x00E .............................................................. 957
USB Test Mode (USBTEST), offset 0x00F ....................................................................... 958
28
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 12:
Register 13:
Register 14:
Register 15:
Register 16:
Register 17:
Register 18:
Register 19:
Register 20:
Register 21:
Register 22:
Register 23:
Register 24:
Register 25:
Register 26:
Register 27:
Register 28:
Register 29:
Register 30:
Register 31:
Register 32:
Register 33:
Register 34:
Register 35:
Register 36:
Register 37:
Register 38:
Register 39:
Register 40:
Register 41:
Register 42:
Register 43:
Register 44:
Register 45:
Register 46:
Register 47:
Register 48:
Register 49:
Register 50:
Register 51:
Register 52:
Register 53:
Register 54:
Register 55:
Register 56:
Register 57:
Register 58:
Register 59:
USB FIFO Endpoint 0 (USBFIFO0), offset 0x020 ............................................................. 960
USB FIFO Endpoint 1 (USBFIFO1), offset 0x024 ............................................................. 960
USB FIFO Endpoint 2 (USBFIFO2), offset 0x028 ............................................................. 960
USB FIFO Endpoint 3 (USBFIFO3), offset 0x02C ............................................................ 960
USB FIFO Endpoint 4 (USBFIFO4), offset 0x030 ............................................................. 960
USB FIFO Endpoint 5 (USBFIFO5), offset 0x034 ............................................................. 960
USB FIFO Endpoint 6 (USBFIFO6), offset 0x038 ............................................................. 960
USB FIFO Endpoint 7 (USBFIFO7), offset 0x03C ............................................................ 960
USB FIFO Endpoint 8 (USBFIFO8), offset 0x040 ............................................................. 960
USB FIFO Endpoint 9 (USBFIFO9), offset 0x044 ............................................................. 960
USB FIFO Endpoint 10 (USBFIFO10), offset 0x048 ......................................................... 960
USB FIFO Endpoint 11 (USBFIFO11), offset 0x04C ......................................................... 960
USB FIFO Endpoint 12 (USBFIFO12), offset 0x050 ......................................................... 960
USB FIFO Endpoint 13 (USBFIFO13), offset 0x054 ......................................................... 960
USB FIFO Endpoint 14 (USBFIFO14), offset 0x058 ......................................................... 960
USB FIFO Endpoint 15 (USBFIFO15), offset 0x05C ......................................................... 960
USB Device Control (USBDEVCTL), offset 0x060 ............................................................ 962
USB Transmit Dynamic FIFO Sizing (USBTXFIFOSZ), offset 0x062 ................................. 964
USB Receive Dynamic FIFO Sizing (USBRXFIFOSZ), offset 0x063 .................................. 964
USB Transmit FIFO Start Address (USBTXFIFOADD), offset 0x064 ................................. 965
USB Receive FIFO Start Address (USBRXFIFOADD), offset 0x066 .................................. 965
USB Connect Timing (USBCONTIM), offset 0x07A .......................................................... 966
USB OTG VBUS Pulse Timing (USBVPLEN), offset 0x07B .............................................. 967
USB Full-Speed Last Transaction to End of Frame Timing (USBFSEOF), offset 0x07D ...... 968
USB Low-Speed Last Transaction to End of Frame Timing (USBLSEOF), offset 0x07E ...... 969
USB Transmit Functional Address Endpoint 0 (USBTXFUNCADDR0), offset 0x080 ........... 970
USB Transmit Functional Address Endpoint 1 (USBTXFUNCADDR1), offset 0x088 ........... 970
USB Transmit Functional Address Endpoint 2 (USBTXFUNCADDR2), offset 0x090 ........... 970
USB Transmit Functional Address Endpoint 3 (USBTXFUNCADDR3), offset 0x098 ........... 970
USB Transmit Functional Address Endpoint 4 (USBTXFUNCADDR4), offset 0x0A0 ........... 970
USB Transmit Functional Address Endpoint 5 (USBTXFUNCADDR5), offset 0x0A8 ........... 970
USB Transmit Functional Address Endpoint 6 (USBTXFUNCADDR6), offset 0x0B0 ........... 970
USB Transmit Functional Address Endpoint 7 (USBTXFUNCADDR7), offset 0x0B8 ........... 970
USB Transmit Functional Address Endpoint 8 (USBTXFUNCADDR8), offset 0x0C0 .......... 970
USB Transmit Functional Address Endpoint 9 (USBTXFUNCADDR9), offset 0x0C8 .......... 970
USB Transmit Functional Address Endpoint 10 (USBTXFUNCADDR10), offset 0x0D0 ....... 970
USB Transmit Functional Address Endpoint 11 (USBTXFUNCADDR11), offset 0x0D8 ....... 970
USB Transmit Functional Address Endpoint 12 (USBTXFUNCADDR12), offset 0x0E0 ....... 970
USB Transmit Functional Address Endpoint 13 (USBTXFUNCADDR13), offset 0x0E8 ....... 970
USB Transmit Functional Address Endpoint 14 (USBTXFUNCADDR14), offset 0x0F0 ....... 970
USB Transmit Functional Address Endpoint 15 (USBTXFUNCADDR15), offset 0x0F8 ....... 970
USB Transmit Hub Address Endpoint 0 (USBTXHUBADDR0), offset 0x082 ...................... 972
USB Transmit Hub Address Endpoint 1 (USBTXHUBADDR1), offset 0x08A ...................... 972
USB Transmit Hub Address Endpoint 2 (USBTXHUBADDR2), offset 0x092 ...................... 972
USB Transmit Hub Address Endpoint 3 (USBTXHUBADDR3), offset 0x09A ...................... 972
USB Transmit Hub Address Endpoint 4 (USBTXHUBADDR4), offset 0x0A2 ...................... 972
USB Transmit Hub Address Endpoint 5 (USBTXHUBADDR5), offset 0x0AA ...................... 972
USB Transmit Hub Address Endpoint 6 (USBTXHUBADDR6), offset 0x0B2 ...................... 972
July 03, 2014
29
Texas Instruments-Production Data
Table of Contents
Register 60:
Register 61:
Register 62:
Register 63:
Register 64:
Register 65:
Register 66:
Register 67:
Register 68:
Register 69:
Register 70:
Register 71:
Register 72:
Register 73:
Register 74:
Register 75:
Register 76:
Register 77:
Register 78:
Register 79:
Register 80:
Register 81:
Register 82:
Register 83:
Register 84:
Register 85:
Register 86:
Register 87:
Register 88:
Register 89:
Register 90:
Register 91:
Register 92:
Register 93:
Register 94:
Register 95:
Register 96:
Register 97:
Register 98:
Register 99:
Register 100:
Register 101:
Register 102:
Register 103:
Register 104:
Register 105:
Register 106:
Register 107:
USB Transmit Hub Address Endpoint 7 (USBTXHUBADDR7), offset 0x0BA ...................... 972
USB Transmit Hub Address Endpoint 8 (USBTXHUBADDR8), offset 0x0C2 ...................... 972
USB Transmit Hub Address Endpoint 9 (USBTXHUBADDR9), offset 0x0CA ..................... 972
USB Transmit Hub Address Endpoint 10 (USBTXHUBADDR10), offset 0x0D2 .................. 972
USB Transmit Hub Address Endpoint 11 (USBTXHUBADDR11), offset 0x0DA .................. 972
USB Transmit Hub Address Endpoint 12 (USBTXHUBADDR12), offset 0x0E2 .................. 972
USB Transmit Hub Address Endpoint 13 (USBTXHUBADDR13), offset 0x0EA .................. 972
USB Transmit Hub Address Endpoint 14 (USBTXHUBADDR14), offset 0x0F2 .................. 972
USB Transmit Hub Address Endpoint 15 (USBTXHUBADDR15), offset 0x0FA .................. 972
USB Transmit Hub Port Endpoint 0 (USBTXHUBPORT0), offset 0x083 ............................. 974
USB Transmit Hub Port Endpoint 1 (USBTXHUBPORT1), offset 0x08B ............................ 974
USB Transmit Hub Port Endpoint 2 (USBTXHUBPORT2), offset 0x093 ............................. 974
USB Transmit Hub Port Endpoint 3 (USBTXHUBPORT3), offset 0x09B ............................ 974
USB Transmit Hub Port Endpoint 4 (USBTXHUBPORT4), offset 0x0A3 ............................ 974
USB Transmit Hub Port Endpoint 5 (USBTXHUBPORT5), offset 0x0AB ............................ 974
USB Transmit Hub Port Endpoint 6 (USBTXHUBPORT6), offset 0x0B3 ............................ 974
USB Transmit Hub Port Endpoint 7 (USBTXHUBPORT7), offset 0x0BB ............................ 974
USB Transmit Hub Port Endpoint 8 (USBTXHUBPORT8), offset 0x0C3 ............................ 974
USB Transmit Hub Port Endpoint 9 (USBTXHUBPORT9), offset 0x0CB ............................ 974
USB Transmit Hub Port Endpoint 10 (USBTXHUBPORT10), offset 0x0D3 ........................ 974
USB Transmit Hub Port Endpoint 11 (USBTXHUBPORT11), offset 0x0DB ......................... 974
USB Transmit Hub Port Endpoint 12 (USBTXHUBPORT12), offset 0x0E3 ......................... 974
USB Transmit Hub Port Endpoint 13 (USBTXHUBPORT13), offset 0x0EB ........................ 974
USB Transmit Hub Port Endpoint 14 (USBTXHUBPORT14), offset 0x0F3 ......................... 974
USB Transmit Hub Port Endpoint 15 (USBTXHUBPORT15), offset 0x0FB ........................ 974
USB Receive Functional Address Endpoint 1 (USBRXFUNCADDR1), offset 0x08C ........... 976
USB Receive Functional Address Endpoint 2 (USBRXFUNCADDR2), offset 0x094 ........... 976
USB Receive Functional Address Endpoint 3 (USBRXFUNCADDR3), offset 0x09C ........... 976
USB Receive Functional Address Endpoint 4 (USBRXFUNCADDR4), offset 0x0A4 ........... 976
USB Receive Functional Address Endpoint 5 (USBRXFUNCADDR5), offset 0x0AC .......... 976
USB Receive Functional Address Endpoint 6 (USBRXFUNCADDR6), offset 0x0B4 ........... 976
USB Receive Functional Address Endpoint 7 (USBRXFUNCADDR7), offset 0x0BC .......... 976
USB Receive Functional Address Endpoint 8 (USBRXFUNCADDR8), offset 0x0C4 ........... 976
USB Receive Functional Address Endpoint 9 (USBRXFUNCADDR9), offset 0x0CC .......... 976
USB Receive Functional Address Endpoint 10 (USBRXFUNCADDR10), offset 0x0D4 ....... 976
USB Receive Functional Address Endpoint 11 (USBRXFUNCADDR11), offset 0x0DC ....... 976
USB Receive Functional Address Endpoint 12 (USBRXFUNCADDR12), offset 0x0E4 ....... 976
USB Receive Functional Address Endpoint 13 (USBRXFUNCADDR13), offset 0x0EC ....... 976
USB Receive Functional Address Endpoint 14 (USBRXFUNCADDR14), offset 0x0F4 ....... 976
USB Receive Functional Address Endpoint 15 (USBRXFUNCADDR15), offset 0x0FC ....... 976
USB Receive Hub Address Endpoint 1 (USBRXHUBADDR1), offset 0x08E ...................... 978
USB Receive Hub Address Endpoint 2 (USBRXHUBADDR2), offset 0x096 ....................... 978
USB Receive Hub Address Endpoint 3 (USBRXHUBADDR3), offset 0x09E ...................... 978
USB Receive Hub Address Endpoint 4 (USBRXHUBADDR4), offset 0x0A6 ...................... 978
USB Receive Hub Address Endpoint 5 (USBRXHUBADDR5), offset 0x0AE ...................... 978
USB Receive Hub Address Endpoint 6 (USBRXHUBADDR6), offset 0x0B6 ...................... 978
USB Receive Hub Address Endpoint 7 (USBRXHUBADDR7), offset 0x0BE ...................... 978
USB Receive Hub Address Endpoint 8 (USBRXHUBADDR8), offset 0x0C6 ...................... 978
30
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 108:
Register 109:
Register 110:
Register 111:
Register 112:
Register 113:
Register 114:
Register 115:
Register 116:
Register 117:
Register 118:
Register 119:
Register 120:
Register 121:
Register 122:
Register 123:
Register 124:
Register 125:
Register 126:
Register 127:
Register 128:
Register 129:
Register 130:
Register 131:
Register 132:
Register 133:
Register 134:
Register 135:
Register 136:
Register 137:
Register 138:
Register 139:
Register 140:
Register 141:
Register 142:
Register 143:
Register 144:
Register 145:
Register 146:
Register 147:
Register 148:
Register 149:
Register 150:
Register 151:
Register 152:
Register 153:
Register 154:
Register 155:
USB Receive Hub Address Endpoint 9 (USBRXHUBADDR9), offset 0x0CE ...................... 978
USB Receive Hub Address Endpoint 10 (USBRXHUBADDR10), offset 0x0D6 ................... 978
USB Receive Hub Address Endpoint 11 (USBRXHUBADDR11), offset 0x0DE ................... 978
USB Receive Hub Address Endpoint 12 (USBRXHUBADDR12), offset 0x0E6 ................... 978
USB Receive Hub Address Endpoint 13 (USBRXHUBADDR13), offset 0x0EE .................. 978
USB Receive Hub Address Endpoint 14 (USBRXHUBADDR14), offset 0x0F6 ................... 978
USB Receive Hub Address Endpoint 15 (USBRXHUBADDR15), offset 0x0FE ................... 978
USB Receive Hub Port Endpoint 1 (USBRXHUBPORT1), offset 0x08F ............................. 980
USB Receive Hub Port Endpoint 2 (USBRXHUBPORT2), offset 0x097 ............................. 980
USB Receive Hub Port Endpoint 3 (USBRXHUBPORT3), offset 0x09F ............................. 980
USB Receive Hub Port Endpoint 4 (USBRXHUBPORT4), offset 0x0A7 ............................. 980
USB Receive Hub Port Endpoint 5 (USBRXHUBPORT5), offset 0x0AF ............................. 980
USB Receive Hub Port Endpoint 6 (USBRXHUBPORT6), offset 0x0B7 ............................. 980
USB Receive Hub Port Endpoint 7 (USBRXHUBPORT7), offset 0x0BF ............................. 980
USB Receive Hub Port Endpoint 8 (USBRXHUBPORT8), offset 0x0C7 ............................. 980
USB Receive Hub Port Endpoint 9 (USBRXHUBPORT9), offset 0x0CF ............................ 980
USB Receive Hub Port Endpoint 10 (USBRXHUBPORT10), offset 0x0D7 ......................... 980
USB Receive Hub Port Endpoint 11 (USBRXHUBPORT11), offset 0x0DF ......................... 980
USB Receive Hub Port Endpoint 12 (USBRXHUBPORT12), offset 0x0E7 ......................... 980
USB Receive Hub Port Endpoint 13 (USBRXHUBPORT13), offset 0x0EF ......................... 980
USB Receive Hub Port Endpoint 14 (USBRXHUBPORT14), offset 0x0F7 ......................... 980
USB Receive Hub Port Endpoint 15 (USBRXHUBPORT15), offset 0x0FF ......................... 980
USB Maximum Transmit Data Endpoint 1 (USBTXMAXP1), offset 0x110 .......................... 982
USB Maximum Transmit Data Endpoint 2 (USBTXMAXP2), offset 0x120 .......................... 982
USB Maximum Transmit Data Endpoint 3 (USBTXMAXP3), offset 0x130 .......................... 982
USB Maximum Transmit Data Endpoint 4 (USBTXMAXP4), offset 0x140 .......................... 982
USB Maximum Transmit Data Endpoint 5 (USBTXMAXP5), offset 0x150 .......................... 982
USB Maximum Transmit Data Endpoint 6 (USBTXMAXP6), offset 0x160 .......................... 982
USB Maximum Transmit Data Endpoint 7 (USBTXMAXP7), offset 0x170 .......................... 982
USB Maximum Transmit Data Endpoint 8 (USBTXMAXP8), offset 0x180 .......................... 982
USB Maximum Transmit Data Endpoint 9 (USBTXMAXP9), offset 0x190 .......................... 982
USB Maximum Transmit Data Endpoint 10 (USBTXMAXP10), offset 0x1A0 ...................... 982
USB Maximum Transmit Data Endpoint 11 (USBTXMAXP11), offset 0x1B0 ....................... 982
USB Maximum Transmit Data Endpoint 12 (USBTXMAXP12), offset 0x1C0 ...................... 982
USB Maximum Transmit Data Endpoint 13 (USBTXMAXP13), offset 0x1D0 ...................... 982
USB Maximum Transmit Data Endpoint 14 (USBTXMAXP14), offset 0x1E0 ...................... 982
USB Maximum Transmit Data Endpoint 15 (USBTXMAXP15), offset 0x1F0 ...................... 982
USB Control and Status Endpoint 0 Low (USBCSRL0), offset 0x102 ................................. 984
USB Control and Status Endpoint 0 High (USBCSRH0), offset 0x103 ............................... 988
USB Receive Byte Count Endpoint 0 (USBCOUNT0), offset 0x108 ................................... 990
USB Type Endpoint 0 (USBTYPE0), offset 0x10A ............................................................ 991
USB NAK Limit (USBNAKLMT), offset 0x10B .................................................................. 992
USB Transmit Control and Status Endpoint 1 Low (USBTXCSRL1), offset 0x112 ............... 993
USB Transmit Control and Status Endpoint 2 Low (USBTXCSRL2), offset 0x122 ............... 993
USB Transmit Control and Status Endpoint 3 Low (USBTXCSRL3), offset 0x132 ............... 993
USB Transmit Control and Status Endpoint 4 Low (USBTXCSRL4), offset 0x142 ............... 993
USB Transmit Control and Status Endpoint 5 Low (USBTXCSRL5), offset 0x152 ............... 993
USB Transmit Control and Status Endpoint 6 Low (USBTXCSRL6), offset 0x162 ............... 993
July 03, 2014
31
Texas Instruments-Production Data
Table of Contents
Register 156:
Register 157:
Register 158:
Register 159:
Register 160:
Register 161:
Register 162:
Register 163:
Register 164:
Register 165:
Register 166:
Register 167:
Register 168:
Register 169:
Register 170:
Register 171:
Register 172:
Register 173:
Register 174:
Register 175:
Register 176:
Register 177:
Register 178:
Register 179:
Register 180:
Register 181:
Register 182:
Register 183:
Register 184:
Register 185:
Register 186:
Register 187:
Register 188:
Register 189:
Register 190:
Register 191:
Register 192:
Register 193:
Register 194:
Register 195:
Register 196:
Register 197:
Register 198:
Register 199:
Register 200:
Register 201:
Register 202:
Register 203:
USB Transmit Control and Status Endpoint 7 Low (USBTXCSRL7), offset 0x172 ............... 993
USB Transmit Control and Status Endpoint 8 Low (USBTXCSRL8), offset 0x182 ............... 993
USB Transmit Control and Status Endpoint 9 Low (USBTXCSRL9), offset 0x192 ............... 993
USB Transmit Control and Status Endpoint 10 Low (USBTXCSRL10), offset 0x1A2 ........... 993
USB Transmit Control and Status Endpoint 11 Low (USBTXCSRL11), offset 0x1B2 ........... 993
USB Transmit Control and Status Endpoint 12 Low (USBTXCSRL12), offset 0x1C2 .......... 993
USB Transmit Control and Status Endpoint 13 Low (USBTXCSRL13), offset 0x1D2 .......... 993
USB Transmit Control and Status Endpoint 14 Low (USBTXCSRL14), offset 0x1E2 ........... 993
USB Transmit Control and Status Endpoint 15 Low (USBTXCSRL15), offset 0x1F2 ........... 993
USB Transmit Control and Status Endpoint 1 High (USBTXCSRH1), offset 0x113 .............. 998
USB Transmit Control and Status Endpoint 2 High (USBTXCSRH2), offset 0x123 ............. 998
USB Transmit Control and Status Endpoint 3 High (USBTXCSRH3), offset 0x133 ............. 998
USB Transmit Control and Status Endpoint 4 High (USBTXCSRH4), offset 0x143 ............. 998
USB Transmit Control and Status Endpoint 5 High (USBTXCSRH5), offset 0x153 ............. 998
USB Transmit Control and Status Endpoint 6 High (USBTXCSRH6), offset 0x163 ............. 998
USB Transmit Control and Status Endpoint 7 High (USBTXCSRH7), offset 0x173 ............. 998
USB Transmit Control and Status Endpoint 8 High (USBTXCSRH8), offset 0x183 ............. 998
USB Transmit Control and Status Endpoint 9 High (USBTXCSRH9), offset 0x193 ............. 998
USB Transmit Control and Status Endpoint 10 High (USBTXCSRH10), offset 0x1A3 ......... 998
USB Transmit Control and Status Endpoint 11 High (USBTXCSRH11), offset 0x1B3 .......... 998
USB Transmit Control and Status Endpoint 12 High (USBTXCSRH12), offset 0x1C3 ......... 998
USB Transmit Control and Status Endpoint 13 High (USBTXCSRH13), offset 0x1D3 ......... 998
USB Transmit Control and Status Endpoint 14 High (USBTXCSRH14), offset 0x1E3 ......... 998
USB Transmit Control and Status Endpoint 15 High (USBTXCSRH15), offset 0x1F3 ......... 998
USB Maximum Receive Data Endpoint 1 (USBRXMAXP1), offset 0x114 ......................... 1002
USB Maximum Receive Data Endpoint 2 (USBRXMAXP2), offset 0x124 ......................... 1002
USB Maximum Receive Data Endpoint 3 (USBRXMAXP3), offset 0x134 ......................... 1002
USB Maximum Receive Data Endpoint 4 (USBRXMAXP4), offset 0x144 ......................... 1002
USB Maximum Receive Data Endpoint 5 (USBRXMAXP5), offset 0x154 ......................... 1002
USB Maximum Receive Data Endpoint 6 (USBRXMAXP6), offset 0x164 ......................... 1002
USB Maximum Receive Data Endpoint 7 (USBRXMAXP7), offset 0x174 ......................... 1002
USB Maximum Receive Data Endpoint 8 (USBRXMAXP8), offset 0x184 ......................... 1002
USB Maximum Receive Data Endpoint 9 (USBRXMAXP9), offset 0x194 ......................... 1002
USB Maximum Receive Data Endpoint 10 (USBRXMAXP10), offset 0x1A4 ..................... 1002
USB Maximum Receive Data Endpoint 11 (USBRXMAXP11), offset 0x1B4 ..................... 1002
USB Maximum Receive Data Endpoint 12 (USBRXMAXP12), offset 0x1C4 ..................... 1002
USB Maximum Receive Data Endpoint 13 (USBRXMAXP13), offset 0x1D4 ..................... 1002
USB Maximum Receive Data Endpoint 14 (USBRXMAXP14), offset 0x1E4 ..................... 1002
USB Maximum Receive Data Endpoint 15 (USBRXMAXP15), offset 0x1F4 ..................... 1002
USB Receive Control and Status Endpoint 1 Low (USBRXCSRL1), offset 0x116 ............. 1004
USB Receive Control and Status Endpoint 2 Low (USBRXCSRL2), offset 0x126 ............. 1004
USB Receive Control and Status Endpoint 3 Low (USBRXCSRL3), offset 0x136 ............. 1004
USB Receive Control and Status Endpoint 4 Low (USBRXCSRL4), offset 0x146 ............. 1004
USB Receive Control and Status Endpoint 5 Low (USBRXCSRL5), offset 0x156 ............. 1004
USB Receive Control and Status Endpoint 6 Low (USBRXCSRL6), offset 0x166 ............. 1004
USB Receive Control and Status Endpoint 7 Low (USBRXCSRL7), offset 0x176 ............. 1004
USB Receive Control and Status Endpoint 8 Low (USBRXCSRL8), offset 0x186 ............. 1004
USB Receive Control and Status Endpoint 9 Low (USBRXCSRL9), offset 0x196 ............. 1004
32
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 204:
Register 205:
Register 206:
Register 207:
Register 208:
Register 209:
Register 210:
Register 211:
Register 212:
Register 213:
Register 214:
Register 215:
Register 216:
Register 217:
Register 218:
Register 219:
Register 220:
Register 221:
Register 222:
Register 223:
Register 224:
Register 225:
Register 226:
Register 227:
Register 228:
Register 229:
Register 230:
Register 231:
Register 232:
Register 233:
Register 234:
Register 235:
Register 236:
Register 237:
Register 238:
Register 239:
Register 240:
Register 241:
Register 242:
Register 243:
Register 244:
Register 245:
Register 246:
Register 247:
Register 248:
Register 249:
Register 250:
Register 251:
USB Receive Control and Status Endpoint 10 Low (USBRXCSRL10), offset 0x1A6 ......... 1004
USB Receive Control and Status Endpoint 11 Low (USBRXCSRL11), offset 0x1B6 .......... 1004
USB Receive Control and Status Endpoint 12 Low (USBRXCSRL12), offset 0x1C6 ......... 1004
USB Receive Control and Status Endpoint 13 Low (USBRXCSRL13), offset 0x1D6 ......... 1004
USB Receive Control and Status Endpoint 14 Low (USBRXCSRL14), offset 0x1E6 ......... 1004
USB Receive Control and Status Endpoint 15 Low (USBRXCSRL15), offset 0x1F6 ......... 1004
USB Receive Control and Status Endpoint 1 High (USBRXCSRH1), offset 0x117 ............ 1009
USB Receive Control and Status Endpoint 2 High (USBRXCSRH2), offset 0x127 ............ 1009
USB Receive Control and Status Endpoint 3 High (USBRXCSRH3), offset 0x137 ............ 1009
USB Receive Control and Status Endpoint 4 High (USBRXCSRH4), offset 0x147 ............ 1009
USB Receive Control and Status Endpoint 5 High (USBRXCSRH5), offset 0x157 ............ 1009
USB Receive Control and Status Endpoint 6 High (USBRXCSRH6), offset 0x167 ............ 1009
USB Receive Control and Status Endpoint 7 High (USBRXCSRH7), offset 0x177 ............ 1009
USB Receive Control and Status Endpoint 8 High (USBRXCSRH8), offset 0x187 ............ 1009
USB Receive Control and Status Endpoint 9 High (USBRXCSRH9), offset 0x197 ............ 1009
USB Receive Control and Status Endpoint 10 High (USBRXCSRH10), offset 0x1A7 ........ 1009
USB Receive Control and Status Endpoint 11 High (USBRXCSRH11), offset 0x1B7 ........ 1009
USB Receive Control and Status Endpoint 12 High (USBRXCSRH12), offset 0x1C7 ........ 1009
USB Receive Control and Status Endpoint 13 High (USBRXCSRH13), offset 0x1D7 ........ 1009
USB Receive Control and Status Endpoint 14 High (USBRXCSRH14), offset 0x1E7 ........ 1009
USB Receive Control and Status Endpoint 15 High (USBRXCSRH15), offset 0x1F7 ........ 1009
USB Receive Byte Count Endpoint 1 (USBRXCOUNT1), offset 0x118 ............................. 1014
USB Receive Byte Count Endpoint 2 (USBRXCOUNT2), offset 0x128 ............................ 1014
USB Receive Byte Count Endpoint 3 (USBRXCOUNT3), offset 0x138 ............................ 1014
USB Receive Byte Count Endpoint 4 (USBRXCOUNT4), offset 0x148 ............................ 1014
USB Receive Byte Count Endpoint 5 (USBRXCOUNT5), offset 0x158 ............................ 1014
USB Receive Byte Count Endpoint 6 (USBRXCOUNT6), offset 0x168 ............................ 1014
USB Receive Byte Count Endpoint 7 (USBRXCOUNT7), offset 0x178 ............................ 1014
USB Receive Byte Count Endpoint 8 (USBRXCOUNT8), offset 0x188 ............................ 1014
USB Receive Byte Count Endpoint 9 (USBRXCOUNT9), offset 0x198 ............................ 1014
USB Receive Byte Count Endpoint 10 (USBRXCOUNT10), offset 0x1A8 ........................ 1014
USB Receive Byte Count Endpoint 11 (USBRXCOUNT11), offset 0x1B8 ......................... 1014
USB Receive Byte Count Endpoint 12 (USBRXCOUNT12), offset 0x1C8 ........................ 1014
USB Receive Byte Count Endpoint 13 (USBRXCOUNT13), offset 0x1D8 ........................ 1014
USB Receive Byte Count Endpoint 14 (USBRXCOUNT14), offset 0x1E8 ........................ 1014
USB Receive Byte Count Endpoint 15 (USBRXCOUNT15), offset 0x1F8 ........................ 1014
USB Host Transmit Configure Type Endpoint 1 (USBTXTYPE1), offset 0x11A ................. 1016
USB Host Transmit Configure Type Endpoint 2 (USBTXTYPE2), offset 0x12A ................. 1016
USB Host Transmit Configure Type Endpoint 3 (USBTXTYPE3), offset 0x13A ................. 1016
USB Host Transmit Configure Type Endpoint 4 (USBTXTYPE4), offset 0x14A ................. 1016
USB Host Transmit Configure Type Endpoint 5 (USBTXTYPE5), offset 0x15A ................. 1016
USB Host Transmit Configure Type Endpoint 6 (USBTXTYPE6), offset 0x16A ................. 1016
USB Host Transmit Configure Type Endpoint 7 (USBTXTYPE7), offset 0x17A ................. 1016
USB Host Transmit Configure Type Endpoint 8 (USBTXTYPE8), offset 0x18A ................. 1016
USB Host Transmit Configure Type Endpoint 9 (USBTXTYPE9), offset 0x19A ................. 1016
USB Host Transmit Configure Type Endpoint 10 (USBTXTYPE10), offset 0x1AA ............. 1016
USB Host Transmit Configure Type Endpoint 11 (USBTXTYPE11), offset 0x1BA ............. 1016
USB Host Transmit Configure Type Endpoint 12 (USBTXTYPE12), offset 0x1CA ............. 1016
July 03, 2014
33
Texas Instruments-Production Data
Table of Contents
Register 252:
Register 253:
Register 254:
Register 255:
Register 256:
Register 257:
Register 258:
Register 259:
Register 260:
Register 261:
Register 262:
Register 263:
Register 264:
Register 265:
Register 266:
Register 267:
Register 268:
Register 269:
Register 270:
Register 271:
Register 272:
Register 273:
Register 274:
Register 275:
Register 276:
Register 277:
Register 278:
Register 279:
Register 280:
Register 281:
Register 282:
Register 283:
Register 284:
Register 285:
Register 286:
Register 287:
Register 288:
Register 289:
Register 290:
Register 291:
Register 292:
Register 293:
Register 294:
Register 295:
Register 296:
Register 297:
Register 298:
Register 299:
USB Host Transmit Configure Type Endpoint 13 (USBTXTYPE13), offset 0x1DA ............. 1016
USB Host Transmit Configure Type Endpoint 14 (USBTXTYPE14), offset 0x1EA ............. 1016
USB Host Transmit Configure Type Endpoint 15 (USBTXTYPE15), offset 0x1FA ............. 1016
USB Host Transmit Interval Endpoint 1 (USBTXINTERVAL1), offset 0x11B ..................... 1018
USB Host Transmit Interval Endpoint 2 (USBTXINTERVAL2), offset 0x12B ..................... 1018
USB Host Transmit Interval Endpoint 3 (USBTXINTERVAL3), offset 0x13B ..................... 1018
USB Host Transmit Interval Endpoint 4 (USBTXINTERVAL4), offset 0x14B ..................... 1018
USB Host Transmit Interval Endpoint 5 (USBTXINTERVAL5), offset 0x15B ..................... 1018
USB Host Transmit Interval Endpoint 6 (USBTXINTERVAL6), offset 0x16B ..................... 1018
USB Host Transmit Interval Endpoint 7 (USBTXINTERVAL7), offset 0x17B ..................... 1018
USB Host Transmit Interval Endpoint 8 (USBTXINTERVAL8), offset 0x18B ..................... 1018
USB Host Transmit Interval Endpoint 9 (USBTXINTERVAL9), offset 0x19B ..................... 1018
USB Host Transmit Interval Endpoint 10 (USBTXINTERVAL10), offset 0x1AB ................. 1018
USB Host Transmit Interval Endpoint 11 (USBTXINTERVAL11), offset 0x1BB .................. 1018
USB Host Transmit Interval Endpoint 12 (USBTXINTERVAL12), offset 0x1CB ................. 1018
USB Host Transmit Interval Endpoint 13 (USBTXINTERVAL13), offset 0x1DB ................. 1018
USB Host Transmit Interval Endpoint 14 (USBTXINTERVAL14), offset 0x1EB ................. 1018
USB Host Transmit Interval Endpoint 15 (USBTXINTERVAL15), offset 0x1FB ................. 1018
USB Host Configure Receive Type Endpoint 1 (USBRXTYPE1), offset 0x11C ................. 1020
USB Host Configure Receive Type Endpoint 2 (USBRXTYPE2), offset 0x12C ................. 1020
USB Host Configure Receive Type Endpoint 3 (USBRXTYPE3), offset 0x13C ................. 1020
USB Host Configure Receive Type Endpoint 4 (USBRXTYPE4), offset 0x14C ................. 1020
USB Host Configure Receive Type Endpoint 5 (USBRXTYPE5), offset 0x15C ................. 1020
USB Host Configure Receive Type Endpoint 6 (USBRXTYPE6), offset 0x16C ................. 1020
USB Host Configure Receive Type Endpoint 7 (USBRXTYPE7), offset 0x17C ................. 1020
USB Host Configure Receive Type Endpoint 8 (USBRXTYPE8), offset 0x18C ................. 1020
USB Host Configure Receive Type Endpoint 9 (USBRXTYPE9), offset 0x19C ................. 1020
USB Host Configure Receive Type Endpoint 10 (USBRXTYPE10), offset 0x1AC ............. 1020
USB Host Configure Receive Type Endpoint 11 (USBRXTYPE11), offset 0x1BC ............. 1020
USB Host Configure Receive Type Endpoint 12 (USBRXTYPE12), offset 0x1CC ............. 1020
USB Host Configure Receive Type Endpoint 13 (USBRXTYPE13), offset 0x1DC ............. 1020
USB Host Configure Receive Type Endpoint 14 (USBRXTYPE14), offset 0x1EC ............. 1020
USB Host Configure Receive Type Endpoint 15 (USBRXTYPE15), offset 0x1FC ............. 1020
USB Host Receive Polling Interval Endpoint 1 (USBRXINTERVAL1), offset 0x11D ........... 1022
USB Host Receive Polling Interval Endpoint 2 (USBRXINTERVAL2), offset 0x12D ........... 1022
USB Host Receive Polling Interval Endpoint 3 (USBRXINTERVAL3), offset 0x13D ........... 1022
USB Host Receive Polling Interval Endpoint 4 (USBRXINTERVAL4), offset 0x14D ........... 1022
USB Host Receive Polling Interval Endpoint 5 (USBRXINTERVAL5), offset 0x15D ........... 1022
USB Host Receive Polling Interval Endpoint 6 (USBRXINTERVAL6), offset 0x16D ........... 1022
USB Host Receive Polling Interval Endpoint 7 (USBRXINTERVAL7), offset 0x17D ........... 1022
USB Host Receive Polling Interval Endpoint 8 (USBRXINTERVAL8), offset 0x18D ........... 1022
USB Host Receive Polling Interval Endpoint 9 (USBRXINTERVAL9), offset 0x19D ........... 1022
USB Host Receive Polling Interval Endpoint 10 (USBRXINTERVAL10), offset 0x1AD ...... 1022
USB Host Receive Polling Interval Endpoint 11 (USBRXINTERVAL11), offset 0x1BD ....... 1022
USB Host Receive Polling Interval Endpoint 12 (USBRXINTERVAL12), offset 0x1CD ...... 1022
USB Host Receive Polling Interval Endpoint 13 (USBRXINTERVAL13), offset 0x1DD ...... 1022
USB Host Receive Polling Interval Endpoint 14 (USBRXINTERVAL14), offset 0x1ED ...... 1022
USB Host Receive Polling Interval Endpoint 15 (USBRXINTERVAL15), offset 0x1FD ....... 1022
34
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 300: USB Request Packet Count in Block Transfer Endpoint 1 (USBRQPKTCOUNT1), offset
0x304 .......................................................................................................................... 1024
Register 301: USB Request Packet Count in Block Transfer Endpoint 2 (USBRQPKTCOUNT2), offset
0x308 .......................................................................................................................... 1024
Register 302: USB Request Packet Count in Block Transfer Endpoint 3 (USBRQPKTCOUNT3), offset
0x30C ......................................................................................................................... 1024
Register 303: USB Request Packet Count in Block Transfer Endpoint 4 (USBRQPKTCOUNT4), offset
0x310 .......................................................................................................................... 1024
Register 304: USB Request Packet Count in Block Transfer Endpoint 5 (USBRQPKTCOUNT5), offset
0x314 .......................................................................................................................... 1024
Register 305: USB Request Packet Count in Block Transfer Endpoint 6 (USBRQPKTCOUNT6), offset
0x318 .......................................................................................................................... 1024
Register 306: USB Request Packet Count in Block Transfer Endpoint 7 (USBRQPKTCOUNT7), offset
0x31C ......................................................................................................................... 1024
Register 307: USB Request Packet Count in Block Transfer Endpoint 8 (USBRQPKTCOUNT8), offset
0x320 .......................................................................................................................... 1024
Register 308: USB Request Packet Count in Block Transfer Endpoint 9 (USBRQPKTCOUNT9), offset
0x324 .......................................................................................................................... 1024
Register 309: USB Request Packet Count in Block Transfer Endpoint 10 (USBRQPKTCOUNT10), offset
0x328 .......................................................................................................................... 1024
Register 310: USB Request Packet Count in Block Transfer Endpoint 11 (USBRQPKTCOUNT11), offset
0x32C ......................................................................................................................... 1024
Register 311: USB Request Packet Count in Block Transfer Endpoint 12 (USBRQPKTCOUNT12), offset
0x330 .......................................................................................................................... 1024
Register 312: USB Request Packet Count in Block Transfer Endpoint 13 (USBRQPKTCOUNT13), offset
0x334 .......................................................................................................................... 1024
Register 313: USB Request Packet Count in Block Transfer Endpoint 14 (USBRQPKTCOUNT14), offset
0x338 .......................................................................................................................... 1024
Register 314: USB Request Packet Count in Block Transfer Endpoint 15 (USBRQPKTCOUNT15), offset
0x33C ......................................................................................................................... 1024
Register 315: USB Receive Double Packet Buffer Disable (USBRXDPKTBUFDIS), offset 0x340 ........... 1026
Register 316: USB Transmit Double Packet Buffer Disable (USBTXDPKTBUFDIS), offset 0x342 .......... 1028
Register 317: USB External Power Control (USBEPC), offset 0x400 .................................................... 1030
Register 318: USB External Power Control Raw Interrupt Status (USBEPCRIS), offset 0x404 ............... 1033
Register 319: USB External Power Control Interrupt Mask (USBEPCIM), offset 0x408 .......................... 1034
Register 320: USB External Power Control Interrupt Status and Clear (USBEPCISC), offset 0x40C ....... 1035
Register 321: USB Device RESUME Raw Interrupt Status (USBDRRIS), offset 0x410 .......................... 1036
Register 322: USB Device RESUME Interrupt Mask (USBDRIM), offset 0x414 ..................................... 1037
Register 323: USB Device RESUME Interrupt Status and Clear (USBDRISC), offset 0x418 .................. 1038
Register 324: USB General-Purpose Control and Status (USBGPCS), offset 0x41C ............................. 1039
Register 325: USB VBUS Droop Control (USBVDC), offset 0x430 ....................................................... 1040
Register 326: USB VBUS Droop Control Raw Interrupt Status (USBVDCRIS), offset 0x434 .................. 1041
Register 327: USB VBUS Droop Control Interrupt Mask (USBVDCIM), offset 0x438 ............................. 1042
Register 328: USB VBUS Droop Control Interrupt Status and Clear (USBVDCISC), offset 0x43C .......... 1043
Register 329: USB ID Valid Detect Raw Interrupt Status (USBIDVRIS), offset 0x444 ............................. 1044
Register 330: USB ID Valid Detect Interrupt Mask (USBIDVIM), offset 0x448 ........................................ 1045
Register 331: USB ID Valid Detect Interrupt Status and Clear (USBIDVISC), offset 0x44C .................... 1046
Register 332: USB DMA Select (USBDMASEL), offset 0x450 .............................................................. 1047
July 03, 2014
35
Texas Instruments-Production Data
Table of Contents
Analog Comparators ................................................................................................................. 1049
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 0x000 ................................ 1056
Analog Comparator Raw Interrupt Status (ACRIS), offset 0x004 ..................................... 1057
Analog Comparator Interrupt Enable (ACINTEN), offset 0x008 ....................................... 1058
Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x010 ..................... 1059
Analog Comparator Status 0 (ACSTAT0), offset 0x020 ................................................... 1060
Analog Comparator Status 1 (ACSTAT1), offset 0x040 ................................................... 1060
Analog Comparator Status 2 (ACSTAT2), offset 0x060 ................................................... 1060
Analog Comparator Control 0 (ACCTL0), offset 0x024 ................................................... 1061
Analog Comparator Control 1 (ACCTL1), offset 0x044 ................................................... 1061
Analog Comparator Control 2 (ACCTL2), offset 0x064 ................................................... 1061
Pulse Width Modulator (PWM) .................................................................................................. 1063
Register 1:
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
Register 7:
Register 8:
Register 9:
Register 10:
Register 11:
Register 12:
Register 13:
Register 14:
Register 15:
Register 16:
Register 17:
Register 18:
Register 19:
Register 20:
Register 21:
Register 22:
Register 23:
Register 24:
Register 25:
Register 26:
Register 27:
Register 28:
Register 29:
Register 30:
Register 31:
Register 32:
Register 33:
Register 34:
Register 35:
Register 36:
PWM Master Control (PWMCTL), offset 0x000 .............................................................. 1079
PWM Time Base Sync (PWMSYNC), offset 0x004 ......................................................... 1081
PWM Output Enable (PWMENABLE), offset 0x008 ........................................................ 1082
PWM Output Inversion (PWMINVERT), offset 0x00C ..................................................... 1084
PWM Output Fault (PWMFAULT), offset 0x010 .............................................................. 1086
PWM Interrupt Enable (PWMINTEN), offset 0x014 ......................................................... 1088
PWM Raw Interrupt Status (PWMRIS), offset 0x018 ...................................................... 1090
PWM Interrupt Status and Clear (PWMISC), offset 0x01C .............................................. 1093
PWM Status (PWMSTATUS), offset 0x020 .................................................................... 1096
PWM Fault Condition Value (PWMFAULTVAL), offset 0x024 ........................................... 1098
PWM Enable Update (PWMENUPD), offset 0x028 ......................................................... 1100
PWM0 Control (PWM0CTL), offset 0x040 ...................................................................... 1104
PWM1 Control (PWM1CTL), offset 0x080 ...................................................................... 1104
PWM2 Control (PWM2CTL), offset 0x0C0 ..................................................................... 1104
PWM3 Control (PWM3CTL), offset 0x100 ...................................................................... 1104
PWM0 Interrupt and Trigger Enable (PWM0INTEN), offset 0x044 ................................... 1109
PWM1 Interrupt and Trigger Enable (PWM1INTEN), offset 0x084 ................................... 1109
PWM2 Interrupt and Trigger Enable (PWM2INTEN), offset 0x0C4 ................................... 1109
PWM3 Interrupt and Trigger Enable (PWM3INTEN), offset 0x104 ................................... 1109
PWM0 Raw Interrupt Status (PWM0RIS), offset 0x048 ................................................... 1112
PWM1 Raw Interrupt Status (PWM1RIS), offset 0x088 ................................................... 1112
PWM2 Raw Interrupt Status (PWM2RIS), offset 0x0C8 .................................................. 1112
PWM3 Raw Interrupt Status (PWM3RIS), offset 0x108 ................................................... 1112
PWM0 Interrupt Status and Clear (PWM0ISC), offset 0x04C .......................................... 1114
PWM1 Interrupt Status and Clear (PWM1ISC), offset 0x08C .......................................... 1114
PWM2 Interrupt Status and Clear (PWM2ISC), offset 0x0CC .......................................... 1114
PWM3 Interrupt Status and Clear (PWM3ISC), offset 0x10C .......................................... 1114
PWM0 Load (PWM0LOAD), offset 0x050 ...................................................................... 1116
PWM1 Load (PWM1LOAD), offset 0x090 ...................................................................... 1116
PWM2 Load (PWM2LOAD), offset 0x0D0 ...................................................................... 1116
PWM3 Load (PWM3LOAD), offset 0x110 ...................................................................... 1116
PWM0 Counter (PWM0COUNT), offset 0x054 ............................................................... 1117
PWM1 Counter (PWM1COUNT), offset 0x094 ............................................................... 1117
PWM2 Counter (PWM2COUNT), offset 0x0D4 .............................................................. 1117
PWM3 Counter (PWM3COUNT), offset 0x114 ............................................................... 1117
PWM0 Compare A (PWM0CMPA), offset 0x058 ............................................................ 1118
36
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 37:
Register 38:
Register 39:
Register 40:
Register 41:
Register 42:
Register 43:
Register 44:
Register 45:
Register 46:
Register 47:
Register 48:
Register 49:
Register 50:
Register 51:
Register 52:
Register 53:
Register 54:
Register 55:
Register 56:
Register 57:
Register 58:
Register 59:
Register 60:
Register 61:
Register 62:
Register 63:
Register 64:
Register 65:
Register 66:
Register 67:
Register 68:
Register 69:
Register 70:
Register 71:
Register 72:
Register 73:
Register 74:
Register 75:
Register 76:
Register 77:
Register 78:
Register 79:
Register 80:
Register 81:
Register 82:
Register 83:
Register 84:
PWM1 Compare A (PWM1CMPA), offset 0x098 ............................................................ 1118
PWM2 Compare A (PWM2CMPA), offset 0x0D8 ............................................................ 1118
PWM3 Compare A (PWM3CMPA), offset 0x118 ............................................................. 1118
PWM0 Compare B (PWM0CMPB), offset 0x05C ............................................................ 1119
PWM1 Compare B (PWM1CMPB), offset 0x09C ............................................................ 1119
PWM2 Compare B (PWM2CMPB), offset 0x0DC ........................................................... 1119
PWM3 Compare B (PWM3CMPB), offset 0x11C ............................................................ 1119
PWM0 Generator A Control (PWM0GENA), offset 0x060 ............................................... 1120
PWM1 Generator A Control (PWM1GENA), offset 0x0A0 ............................................... 1120
PWM2 Generator A Control (PWM2GENA), offset 0x0E0 ............................................... 1120
PWM3 Generator A Control (PWM3GENA), offset 0x120 ............................................... 1120
PWM0 Generator B Control (PWM0GENB), offset 0x064 ............................................... 1123
PWM1 Generator B Control (PWM1GENB), offset 0x0A4 ............................................... 1123
PWM2 Generator B Control (PWM2GENB), offset 0x0E4 ............................................... 1123
PWM3 Generator B Control (PWM3GENB), offset 0x124 ............................................... 1123
PWM0 Dead-Band Control (PWM0DBCTL), offset 0x068 ............................................... 1126
PWM1 Dead-Band Control (PWM1DBCTL), offset 0x0A8 ............................................... 1126
PWM2 Dead-Band Control (PWM2DBCTL), offset 0x0E8 ............................................... 1126
PWM3 Dead-Band Control (PWM3DBCTL), offset 0x128 ............................................... 1126
PWM0 Dead-Band Rising-Edge Delay (PWM0DBRISE), offset 0x06C ............................ 1127
PWM1 Dead-Band Rising-Edge Delay (PWM1DBRISE), offset 0x0AC ............................ 1127
PWM2 Dead-Band Rising-Edge Delay (PWM2DBRISE), offset 0x0EC ............................ 1127
PWM3 Dead-Band Rising-Edge Delay (PWM3DBRISE), offset 0x12C ............................ 1127
PWM0 Dead-Band Falling-Edge-Delay (PWM0DBFALL), offset 0x070 ............................ 1128
PWM1 Dead-Band Falling-Edge-Delay (PWM1DBFALL), offset 0x0B0 ............................ 1128
PWM2 Dead-Band Falling-Edge-Delay (PWM2DBFALL), offset 0x0F0 ............................ 1128
PWM3 Dead-Band Falling-Edge-Delay (PWM3DBFALL), offset 0x130 ............................ 1128
PWM0 Fault Source 0 (PWM0FLTSRC0), offset 0x074 .................................................. 1129
PWM1 Fault Source 0 (PWM1FLTSRC0), offset 0x0B4 .................................................. 1129
PWM2 Fault Source 0 (PWM2FLTSRC0), offset 0x0F4 .................................................. 1129
PWM3 Fault Source 0 (PWM3FLTSRC0), offset 0x134 .................................................. 1129
PWM0 Fault Source 1 (PWM0FLTSRC1), offset 0x078 .................................................. 1131
PWM1 Fault Source 1 (PWM1FLTSRC1), offset 0x0B8 .................................................. 1131
PWM2 Fault Source 1 (PWM2FLTSRC1), offset 0x0F8 .................................................. 1131
PWM3 Fault Source 1 (PWM3FLTSRC1), offset 0x138 .................................................. 1131
PWM0 Minimum Fault Period (PWM0MINFLTPER), offset 0x07C ................................... 1134
PWM1 Minimum Fault Period (PWM1MINFLTPER), offset 0x0BC ................................... 1134
PWM2 Minimum Fault Period (PWM2MINFLTPER), offset 0x0FC ................................... 1134
PWM3 Minimum Fault Period (PWM3MINFLTPER), offset 0x13C ................................... 1134
PWM0 Fault Pin Logic Sense (PWM0FLTSEN), offset 0x800 .......................................... 1135
PWM1 Fault Pin Logic Sense (PWM1FLTSEN), offset 0x880 .......................................... 1135
PWM2 Fault Pin Logic Sense (PWM2FLTSEN), offset 0x900 .......................................... 1135
PWM3 Fault Pin Logic Sense (PWM3FLTSEN), offset 0x980 .......................................... 1135
PWM0 Fault Status 0 (PWM0FLTSTAT0), offset 0x804 ................................................... 1136
PWM1 Fault Status 0 (PWM1FLTSTAT0), offset 0x884 ................................................... 1136
PWM2 Fault Status 0 (PWM2FLTSTAT0), offset 0x904 ................................................... 1136
PWM3 Fault Status 0 (PWM3FLTSTAT0), offset 0x984 ................................................... 1136
PWM0 Fault Status 1 (PWM0FLTSTAT1), offset 0x808 ................................................... 1138
July 03, 2014
37
Texas Instruments-Production Data
Table of Contents
Register 85:
Register 86:
Register 87:
PWM1 Fault Status 1 (PWM1FLTSTAT1), offset 0x888 ................................................... 1138
PWM2 Fault Status 1 (PWM2FLTSTAT1), offset 0x908 ................................................... 1138
PWM3 Fault Status 1 (PWM3FLTSTAT1), offset 0x988 ................................................... 1138
Quadrature Encoder Interface (QEI) ........................................................................................ 1141
Register 1:
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
Register 7:
Register 8:
Register 9:
Register 10:
Register 11:
QEI Control (QEICTL), offset 0x000 ..............................................................................
QEI Status (QEISTAT), offset 0x004 ..............................................................................
QEI Position (QEIPOS), offset 0x008 ............................................................................
QEI Maximum Position (QEIMAXPOS), offset 0x00C .....................................................
QEI Timer Load (QEILOAD), offset 0x010 .....................................................................
QEI Timer (QEITIME), offset 0x014 ...............................................................................
QEI Velocity Counter (QEICOUNT), offset 0x018 ...........................................................
QEI Velocity (QEISPEED), offset 0x01C ........................................................................
QEI Interrupt Enable (QEIINTEN), offset 0x020 .............................................................
QEI Raw Interrupt Status (QEIRIS), offset 0x024 ...........................................................
QEI Interrupt Status and Clear (QEIISC), offset 0x028 ...................................................
38
1148
1151
1152
1153
1154
1155
1156
1157
1158
1160
1162
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Revision History
The revision history table notes changes made between the indicated revisions of the LM3S5791
data sheet.
Table 1. Revision History
Date
July 2014
October 2012
January 2012
Revision
Description
15852.2743 ■
In JTAG chapter, clarified JTAG-to-SWD Switching and SWD-to-JTAG Switching.
■
In System Control chapter, clarified behavior of Reset Cause (RESC) register external reset bit.
■
In Internal memory chapter, noted that the Boot Configuration (BOOTCFG) register requires a
POR before committed changes to the Flash-resident registers take effect.
■
In GPIO chapter, corrected values for GPIOPCTL in the table GPIO Pins With Non-Zero Reset
Values.
■
In UART chapter, clarified that the transmit interrupt is based on a transition through level.
■
In Ordering and Contact Information appendix, moved orderable part numbers table to addendum.
■
Additional minor data sheet clarifications and corrections.
13442.2549 ■
Marked LM3S5791 device as not recommended for new designs (NRND). Device is in production
to support existing customers, but TI does not recommend using this part in a new design.
■
Clarified that all GPIO signals are 5-V tolerant when configured as inputs except for PB0 and PB1,
which are limited to 3.6 V.
■
In the Watchdog Timers chapter, added information on servicing the watchdog timer to the
Initialization and Configuration section.
■
In the General-Purpose Timers chapter, added note to the GPTMTnV registers that in 16-bit mode,
only the lower 16-bits of the register can be written with a new value. Writes to the prescaler bits
have no effect.
■
Corrected reset for the UART Raw Interrupt Status (UARTRIS) register.
■
In the USB chapter, clarified that the USB PHY has internal termination resistors, and thus there is
no need for external resistors.
■
In the Electrical Characteristics chapter, added clarifying footnote to the GPIO Module Characteristics
table.
■
Additional minor data sheet clarifications and corrections.
■
In System Control chapter:
11425
–
Clarified that an external LDO cannot be used.
–
Clarified system clock requirements when the ADC module is in operation.
–
Added important note to write the RCC register before the RCC2 register.
■
In Internal Memory chapter, clarified programming and use of the non-volatile registers.
■
In GPIO chapter, corrected "GPIO Pins With Non-Zero Reset Values" table and added note that if
the same signal is assigned to two different GPIO port pins, the signal is assigned to the port with
the lowest letter.
■
In EPI chapter:
–
Clarified table "Capabilities of Host Bus 8 and Host Bus 16 Modes".
July 03, 2014
39
Texas Instruments-Production Data
Revision History
Table 1. Revision History (continued)
Date
Revision
Description
–
Corrected bit and register resets for FREQ (Frequency Range) in EPI SDRAM Configuration
(EPISDRAMCFG) register.
–
Corrected bit and register resets for MAXWAIT (Maximum Wait) in EPI Host-Bus 8 Configuration
(EPIHB8CFG) and EPI Host-Bus 16 Configuration (EPIHB16CFG) registers. Also clarified
bit descriptions in these registers.
–
Corrected bit definitions for the EPSZ and ERSZ bits in the EPI Address Map (EPIADDRMAP)
register.
–
Corrected size of COUNT bit field in EPI Read FIFO Count (EPIRFIFOCNT) register.
■
In Timer chapter, clarified timer modes and interrupts.
■
In ADC chapter, added "ADC Input Equivalency Diagram".
■
In UART chapter, clarified interrupt behavior.
■
In SSI chapter, corrected SSIClk in the figure "Synchronous Serial Frame Format (Single Transfer)"
and clarified behavior of transmit bits in interrupt registers.
■
In I2C chapter, corrected bit and register reset values for IDLE bit in I2C Master Control/Status
(I2CMCS) register.
■
In USB chapter:
–
Clarified that when the USB module is in operation, MOSC must be provided with a clock source,
and the system clock must be at least 30 MHz.
–
Removed MULTTRAN bit from USB Transmit Hub Address Endpoint n (USBTXHUBADDRn)
and USB Receive Hub Address Endpoint n (USBRXHUBADDRn) registers.
–
Corrected description for the USB Device RESUME Interrupt Mask (USBDRIM) register.
■
In Analog Comparators chapter, clarified internal reference programming.
■
In PWM chapter, clarified PWM Interrupt Enable (PWMINTEN) register description.
■
In Signal Tables chapter, clarified VDDC and LDO pin descriptions.
■
In Electrical Characteristics chapter:
–
In Maximum Ratings table, deleted parameter "Input voltage for a GPIO configured as an analog
input".
–
In Recommended DC Operating Conditions table, corrected values for IOH parameter.
–
In JTAG Characteristics, table, corrected values for parameters "TCK clock Low time" and "TCK
clock High time".
–
In LDO Regulator Characteristics table, added clarifying footnote to CLDO parameter.
–
In System Clock Characteristics with ADC Operation table, added clarifying footnote to Fsysadc
parameter.
–
Added "System Clock Characteristics with USB Operation" table.
–
In Sleep Modes AC Characteristics table, split parameter "Time to wake from interrupt" into
sleep mode and deep-sleep mode parameters.
–
In SSI Characteristics table, corrected value for parameter "SSIClk cycle time".
–
Deleted erroneously included Ethernet Controller tables, since this part does not have Ethernet.
40
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 1. Revision History (continued)
Date
July 2011
Revision
9970
Description
–
In Analog Comparator Characteristics table, added parameter "Input voltage range" and corrected
values for parameter "Input common mode voltage range".
–
In Analog Comparator Voltage Reference Characteristics table, corrected values for absolute
accuracy parameters.
–
Deleted table "USB Controller DC Characteristics".
–
In Nominal Power Consumption table, added parameter for sleep mode.
–
In Maximum Current Consumption section, changed reference value for MOSC and temperature
in tables that follow.
–
Deleted table "External VDDC Source Current Specifications".
■
Additional minor data sheet clarifications and corrections.
■
Corrected "Reset Sources" table.
■
Added missing PICAL (PIOSC Calibrate) bit to DC4 register.
■
Added Important Note that RCC register must be written before RCC2 register.
■
In Hibernation Module chapter, deleted section "Special Considerations When Using a 4.194304-MHz
Crystal" as the content was added to the errata document.
■
Added a note that all GPIO signals are 5-V tolerant when configured as inputs except for PB0 and
PB1, which are limited to 3.6 V.
■
Note that the state of the HSE bit in the UARTCTL register has no effect on clock generation in ISO
7816 smart card mode (when the SMART bit in the UARTCTL register is set).
■
Corrected LIN Mode bit names in UART Interrupt Clear (UARTICR) register.
■
Corrected pin number for RST in table "Connections for Unused Signals" (other pin tables were
correct).
■
In the "Operating Characteristics" chapter:
–
In the "Thermal Characteristics" table, the Thermal resistance value was changed.
–
In the "ESD Absolute Maximum Ratings" table, the VESDCDM parameter was changed and the
VESDMM parameter was deleted.
■
The "Electrical Characteristics" chapter was reorganized by module. In addition, some of the
Recommended DC Operating Conditions, LDO Regulator, Clock, GPIO, EPI, ADC, and SSI
characteristics were finalized.
■
Added missing ordering table.
■
Additional minor data sheet clarifications and corrections.
July 03, 2014
41
Texas Instruments-Production Data
Revision History
Table 1. Revision History (continued)
Date
Revision
March 2011
9538
January 2011
9161
Description
■
Clarified "Reset Control" section in the "System Control" chapter.
■
Corrected USB PLL speed in "Main Clock Tree" diagram.
■
Corrected reset value for DMA Channel Wait-on-Request Status (DMAWAITSTAT) register.
■
Corrected "GPIO Pins With Non-Zero Reset Values" table.
■
Added diagram "Host-Bus Write Cycle with Multiplexed Address and Data and ALE with Dual CSn"
to EPI chapter.
■
Clarified that that the timer reload only happens in periodic mode.
■
Clarified that only bit 0 in the Watchdog Control (WDTCTL) register is protected from writes once
set.
■
Added "Sample Averaging Example" diagram to ADC chapter.
■
Corrected "SSI Timing for SPI Frame Format" figure.
■
In "Electrical Characteristics" chapter:
–
Deleted TPORMIN parameter from "Power Characteristics" table, and deleted corresponding
diagram.
–
Corrected tRDYSU parameter in "EPI General-Purpose Interface Characteristics" table and
"General-Purpose Mode iRDY Timing" diagram.
–
Added tADCSAMP sample time parameter to "ADC Characteristics" table.
■
Additional minor data sheet clarifications and corrections.
■
Clarified Main Oscillator verification circuit sequence.
■
Added note that there must be a delay of 3 system clocks after the module clock is enabled before
any of that module's registers are accessed.
■
Added "Example Schematic for Muxed Host-Bus 16 Mode" figure to External Peripheral Interface
(EPI) chapter.
■
Corrected reset of Device Mode (DEVMOD) bitfield in USB General-Purpose Control and Status
(USBGPCS) register.
■
Clarified initialization and configuration procedure in "Analog Comparators" chapter.
■
In Electrical Characteristics chapter:
■
–
Added specification for maximum input voltage on a non-power pin when the microcontroller is
unpowered (VNON parameter in Maximum Ratings table).
–
Replaced Preliminary Current Consumption Specifications with Nominal Power Consumption,
Maximum Current Specifications, and Typical Current Consumption vs. Frequency sections.
–
Clarified Reset, and Power and Brown-out Characteristics and added a new specification for
powering down before powering back up.
–
Added characteristics required when using an external regulator to provide power for VDDC.
Additional minor data sheet clarifications and corrections.
42
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 1. Revision History (continued)
Date
Revision
December 2010
8832
Description
■
Information on Advanced Encryption Standard (AES) cryptography tables and Cyclic Redundancy
Check (CRC) error detection functionality was inadvertently omitted from some datasheets. This
has been added.
■
In APINT register, changed bit name from SYSRESETREQ to SYSRESREQ.
■
Added DEBUG (Debug Priority) bit field to SYSPRI3 register.
■
Clarified Flash memory caution.
■
Restructured the General-Purpose Timer chapter to combine duplicated text.
■
Combined High and Low bit fields in GPTMTAILR, GPTMTAMATCHR, GPTMTAR, GPTMTAV,
GPTMTBILR, GPTMTAMATCHR, GPTMTBR and GPTMTBV registers for compatibility with future
releases.
■
Removed mention of false-start bit detection in the UART chapter. This feature is not supported.
■
Added SSI master clock restriction that SSIClk cannot be faster than 25 MHz.
■
Changed I2C master and slave register base addresses and offsets to be relative to I2C module
base, so register base and offsets were changed for all I2C slave registers.
■
In Electrical Characteristics chapter:
–
Added single-ended clock source input voltage values to "Recommended DC Operating
Conditions" table.
–
Deleted Oscillation mode value from "MOSC Oscillator Input Characteristics" table.
–
Added TVDD2_3 supply voltage parameter to "Reset Characteristics" table.
–
Added "Power-On Reset and Voltage Parameters" timing diagram.
–
Added tALEADD parameter to "EPI Host-Bus 8 and Host-Bus 16 Interface Characteristics" table.
–
Added "Host-Bus 8/16 Mode Muxed Read Timing" and "Host-Bus 8/16 Mode Muxed Write
Timing" timing diagrams.
July 03, 2014
43
Texas Instruments-Production Data
Revision History
Table 1. Revision History (continued)
Date
Revision
September 2010
7794
June 2010
7413
Description
■
Reorganized ARM Cortex-M3 Processor Core, Memory Map and Interrupts chapters, creating two
new chapters, The Cortex-M3 Processor and Cortex-M3 Peripherals. Much additional content was
added, including all the Cortex-M3 registers.
■
Changed register names to be consistent with StellarisWare names: the Cortex-M3 Interrupt
Control and Status (ICSR) register to the Interrupt Control and State (INTCTRL) register, and
the Cortex-M3 Interrupt Set Enable (SETNA) register to the Interrupt 0-31 Set Enable (EN0)
register.
■
In the System Control chapter:
– Corrected Reset Sources table (see Table 5-3 on page 197).
– Added section "Special Considerations for Reset."
■
In the Internal Memory chapter:
– Added clarification of instruction execution during Flash operations.
– Deleted ROM Version (RMVER) register as it is not used.
■
Modified Figure 8-1 on page 403 and Figure 8-2 on page 404 to clarify operation of the GPIO inputs
when used as an alternate function.
■
Corrected GPIOAMSEL bit field in GPIO Analog Mode Select (GPIOAMSEL) register to be eight-bits
wide, bits[7:0].
■
In General-Purpose Timers chapter, clarified operation of the 32-bit RTC mode.
■
In CAN chapter, clarified CAN bit timing examples.
■
In Operating Characteristics chapter, corrected Thermal resistance (junction to ambient) value to
32.
■
In Electrical Characteristics chapter:
– Added "Input voltage for a GPIO configured as an analog input" value to Table 25-1 on page 1247.
– Added ILKG parameter (GPIO input leakage current) to Table 25-17 on page 1256.
– Corrected reset timing in Table 25-5 on page 1251.
– Specified Max value for VREFA in Table 25-23 on page 1263.
– Corrected values for tCLKRF (SSIClk rise/fall time) in Table 25-25 on page 1263.
– Added I2C Characteristics table (see Table 25-26 on page 1265).
■
Added dimensions for Tray and Tape and Reel shipping mediums.
■
In "Thermal Characteristics" table, corrected thermal resistance value from 34 to 32.
®
44
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 1. Revision History (continued)
Date
Revision
June 2010
7299
May 2010
May 2010
March 2010
March 2010
7164
7101
6983
6912
Description
■
Changed memory map ending address for EPI0 mapped peripheral and RAM from 0xCFFF.FFFF
to 0xDFFF.FFFF.
■
Removed 4.194304-MHz crystal as a source for the system clock and PLL.
■
Summarized ROM contents descriptions in the "Internal Memory" chapter and removed various
ROM appendices.
■
Clarified DMA channel terminology: changed name of DMA Channel Alternate Select (DMACHALT)
register to DMA Channel Assignment (DMACHASGN) register, changed CHALT bit field to CHASGN,
and changed terminology from primary and alternate channels to primary and secondary channels.
■
Clarified EPI Main Baud Rate (EPIBAUD) equation.
■
In Signal Tables chapter, added table "Connections for Unused Signals."
■
In "Electrical Characteristics" chapter:
–
In "Reset Characteristics" table, corrected Supply voltage (VDD) rise time.
–
Clarified figure "SDRAM Initialization and Load Mode Register Timing".
–
Added BSEL0n/BSEL1n to EPI timing diagrams.
■
Added data sheets for five new Stellaris® Tempest-class parts: LM3S1R26, LM3S1621, LM3S1B21,
LM3S9781, and LM3S9B81.
■
Additional minor data sheet clarifications and corrections.
■
Added pin table "Possible Pin Assignments for Alternate Functions", which lists the signals based
on number of possible pin assignments. This table can be used to plan how to configure the pins
for a particular functionality.
■
Additional minor data sheet clarifications and corrections.
■
Corrected reset for EPIHB8CFG, EPI_HB16CFG and EPIGPCFG registers.
■
Extended TBRL bit field in GPTMTBR register.
■
Additional minor data sheet clarifications and corrections.
■
Renamed the USER_DBG register to the BOOTCFG register in the Internal Memory chapter. Added
information on how to use a GPIO pin to force the ROM Boot Loader to execute on reset.
■
Added three figures to the ADC chapter on sample phase control.
■
Clarified configuration of USB0VBUS and USB0ID in OTG mode.
July 03, 2014
45
Texas Instruments-Production Data
Revision History
Table 1. Revision History (continued)
Date
Revision
February 2010
6790
Description
■
Added 108-ball BGA package.
■
In "System Control" chapter:
– Clarified functional description for external reset and brown-out reset.
– Clarified Debug Access Port operation after Sleep modes.
– Corrected the reset value of the Run-Mode Clock Configuration 2 (RCC2) register.
■
In "Internal Memory" chapter, clarified wording on Flash memory access errors and added a section
on interrupts to the Flash memory description.
■
In "External Peripheral Interface" chapter:
– Added clarification about byte selects and dual chip selects.
– Added timing diagrams for continuous-read mode (formerly SRAM mode).
– Corrected reset values of EPI Write FIFO Count (EPIWFIFOCNT) and EPI Raw Interrupt
Status (EPIRIS) registers.
■
Added clarification about timer operating modes and added register descriptions for the GPTM
Timer n Prescale Match (GPTMTnPMR) registers.
■
Clarified register descriptions for GPTM Timer A Value (GPTMTAV) and GPTM Timer B Value
(GPTMTBV) registers.
■
Corrected the reset value of the ADC Sample Sequence Result FIFO n (ADCSSFIFOn) registers.
■
Added ADC Sample Phase Control (ADCSPC) register at offset 0x24.
■
Added caution note to the I2C Master Timer Period (I2CMTPR) register description and changed
field width to 7 bits.
■
In the "Controller Area Network" chapter, added clarification about reading from the CAN FIFO
buffer.
■
Added Session Disconnect (DISCON) bit to the USB General Interrupt Status (USBIS) and
USB Interrupt Enable (USBIE) registers.
■
Made these changes to the Operating Characteristics chapter:
– Added storage temperature ratings to "Temperature Characteristics" table
– Added "ESD Absolute Maximum Ratings" table
■
Made these changes to the Electrical Characteristics chapter:
– In "Flash Memory Characteristics" table, corrected Mass erase time
– Added sleep and deep-sleep wake-up times ("Sleep Modes AC Characteristics" table)
– In "Reset Characteristics" table, corrected units for supply voltage (VDD) rise time
– Added table entry for VDD3ON power consumption to Table 25-34 on page 1268.
■
Added additional DriverLib functions to appendix.
46
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 1. Revision History (continued)
Date
Revision
October 2009
6458
Description
®
■
Released new 1000, 3000, 5000 and 9000 series Stellaris devices.
■
The IDCODE value was corrected to be 0x4BA0.0477.
■
Clarified that the NMISET bit in the ICSR register in the NVIC is also a source for NMI.
■
Clarified the use of the LDO.
■
To clarify clock operation, reorganized clocking section, changed the USEFRACT bit to the DIV400
bit and the FRACT bit to the SYSDIV2LSB bit in the RCC2 register, added tables, and rewrote
descriptions.
■
Corrected bit description of the DSDIVORIDE field in the DSLPCLKCFG register.
■
Removed the DSFLASHCFG register at System Control offset 0x14C as it does not function correctly.
■
Removed the MAXADC1SPD and MAXADC0SPD fields from the DCGC0 as they have no function in
deep-sleep mode.
■
Corrected address offsets for the Flash Write Buffer (FWBn) registers.
■
Added Flash Control (FCTL) register at Internal memory offset 0x0F8 to help control frequent
power cycling when hibernation is not used.
■
Changed the name of the EPI channels for clarification: EPI0_TX became EPI0_WFIFO and EPI0_RX
became EPI0_NBRFIFO. This change was also made in the DC7 bit descriptions.
■
Removed the DMACHIS register at DMA module offset 0x504 as it does not function correctly.
■
Corrected alternate channel assignments for the µDMA controller.
■
Major improvements to the EPI chapter.
■
EPISDRAMCFG2 register was deleted as its function is not needed.
■
Clarified CAN bit timing and corrected examples.
■
Clarified PWM source for ADC triggering
■
Corrected ADDR field in the USBTXFIFOADD register to be 9 bits instead of 13 bits.
■
Changed SSI set up and hold times to be expressed in system clocks, not ns.
■
Updated Electrical Characteristics chapter with latest data. Changes were made to ADC and EPI
content.
■
Additional minor data sheet clarifications and corrections.
July 03, 2014
47
Texas Instruments-Production Data
Revision History
Table 1. Revision History (continued)
Date
Revision
July 2009
5930
Description
■
Added "Non-Blocking Read Cycle", "Normal Read Cycle", and "Write Cycle" sections to EPI chapter.
■
Corrected values for MAXADC0SPD and MAXADC1SPD bits in DC1, RCGC0, SCGC0, and DCGC0
registers.
■
Corrected figure "TI Synchronous Serial Frame Format (Single Transfer)".
■
Made a number of corrections to the Electrical Characteristics chapter:
–
Deleted VBAT and VREFA parameters from and added footnotes to Recommended DC Operating
Conditions table.
–
Deleted Nominal and Maximum Current Specifications section.
–
Modified EPI SDRAM Characteristics table:
•
Changed tEPIR to tSDRAMR and deleted values for 2-mA and 4-mA drive.
•
Changed tEPIF to tSDRAMF and deleted values for 2-mA and 4-mA drive.
–
Changed values for tCOV, tCOI, and tCOT parameters in EPI SDRAM Interface Characteristics
table.
–
Deleted SDRAM Read Command Timing, SDRAM Write Command Timing, SDRAM Write Burst
Timing, SDRAM Precharge Command Timing and SDRAM CAS Latency Timing figures and
replaced with SDRAM Read Timing and SDRAM Write Timing figures.
–
Modified Host-Bus 8/16 Mode Write Timing figure.
–
Modified General-Purpose Mode Read and Write Timing figure.
–
Modified values for tDV and tDI parameters, and deleted tOD parameter from EPI General-Purpose
Interface Characteristics figure.
–
Major changes to ADC Characteristics tables, including adding additonal tables and diagram.
■
Added missing ROM_I2SIntStatus function to ROM DriverLib Functions appendix.
■
Corrected ordering part numbers.
■
Additional minor data sheet clarifications and corrections.
48
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 1. Revision History (continued)
Date
Revision
June 2009
5779
May 2009
5285
Description
■
In System Control chapter, clarified power-on reset and external reset pin descriptions in "Reset
Sources" section.
■
Added missing comparator output pin bits to DC3 register; reset value changed as well.
■
Clarified explanation of nonvolatile register programming in Internal Memory chapter.
■
Added explanation of reset value to FMPRE0/1/2/3, FMPPE0/1/2/3, USER_DBG, and USER_REG0
registers.
■
In Request Type Support table in DMA chapter, corrected general-purpose timer row.
■
In General-Purpose Timers chapter, clarified DMA operation.
■
Added table "Preliminary Current Consumption" to Characteristics chapter.
■
Corrected Nom and Max values in EPI Characteristics table.
■
Added "CSn to output invalid" parameter to EPI table "EPI Host-Bus 8 and Host-Bus 16 Interface
Characteristics" and figure "Host-Bus 8/16 Mode Read Timing".
■
Corrected INL, DNL, OFF and GAIN values in ADC Characteristics table.
■
Updated ROM DriverLib appendix with RevC0 functions.
■
Updated part ordering numbers.
■
Additional minor data sheet clarifications and corrections.
Started tracking revision history.
July 03, 2014
49
Texas Instruments-Production Data
About This Document
About This Document
This data sheet provides reference information for the LM3S5791 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 related documents are available on the Stellaris web site at www.ti.com/stellaris:
■ Stellaris® Errata
■ ARM® Cortex™-M3 Errata
■ Cortex™-M3/M4 Instruction Set Technical User's Manual
■ Stellaris® Boot Loader User's Guide
■ Stellaris® Graphics Library User's Guide
■ Stellaris® Peripheral Driver Library User's Guide
■ Stellaris® ROM User’s Guide
■ Stellaris® USB Library User's Guide
The following related documents are also referenced:
■ ARM® Debug Interface V5 Architecture Specification
■ ARM® Embedded Trace Macrocell Architecture Specification
■ IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture
This documentation list was current as of publication date. Please check the web site for additional
documentation, including application notes and white papers.
50
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Documentation Conventions
This document uses the conventions shown in Table 2 on page 51.
Table 2. Documentation Conventions
Notation
Meaning
General Register Notation
REGISTER
APB registers are indicated in uppercase bold. For example, PBORCTL is the Power-On and
Brown-Out Reset Control register. If a register name contains a lowercase n, it represents more
than one register. For example, SRCRn represents any (or all) of the three Software Reset Control
registers: SRCR0, SRCR1 , and SRCR2.
bit
A single bit in a register.
bit field
Two or more consecutive and related bits.
offset 0xnnn
A hexadecimal increment to a register's address, relative to that module's base address as specified
in Table 2-4 on page 94.
Register N
Registers are numbered consecutively throughout the document to aid in referencing them. The
register number has no meaning to software.
reserved
Register bits marked reserved are reserved for future use. In most cases, reserved bits are set to
0; however, user software should not rely on the value of a reserved bit. To provide software
compatibility with future products, the value of a reserved bit should be preserved across a
read-modify-write operation.
yy:xx
The range of register bits inclusive from xx to yy. For example, 31:15 means bits 15 through 31 in
that register.
Register Bit/Field
Types
This value in the register bit diagram indicates whether software running on the controller can
change the value of the bit field.
RC
Software can read this field. The bit or field is cleared by hardware after reading the bit/field.
RO
Software can read this field. Always write the chip reset value.
R/W
Software can read or write this field.
R/WC
Software can read or write this field. Writing to it with any value clears the register.
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.
R/W1S
Software can read or write a 1 to this field. A write of a 0 to a R/W1S bit does not affect the bit
value in the register.
W1C
Software can write this field. A write of a 0 to a W1C bit does not affect the bit value in the register.
A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged. A
read of the register returns no meaningful data.
This register is typically used to clear the corresponding bit in an interrupt register.
WO
Only a write by software is valid; a read of the register returns no meaningful data.
Register Bit/Field
Reset Value
This value in the register bit diagram shows the bit/field value after any reset, unless noted.
0
Bit cleared to 0 on chip reset.
1
Bit set to 1 on chip reset.
-
Nondeterministic.
Pin/Signal Notation
[]
Pin alternate function; a pin defaults to the signal without the brackets.
pin
Refers to the physical connection on the package.
signal
Refers to the electrical signal encoding of a pin.
July 03, 2014
51
Texas Instruments-Production Data
About This Document
Table 2. Documentation Conventions (continued)
Notation
Meaning
assert a signal
Change the value of the signal from the logically False state to the logically True state. For active
High signals, the asserted signal value is 1 (High); for active Low signals, the asserted signal value
is 0 (Low). The active polarity (High or Low) is defined by the signal name (see SIGNAL and SIGNAL
below).
deassert a signal
Change the value of the signal from the logically True state to the logically False state.
SIGNAL
Signal names are in uppercase and in the Courier font. An overbar on a signal name indicates that
it is active Low. To assert SIGNAL is to drive it Low; to deassert SIGNAL is to drive it High.
SIGNAL
Signal names are in uppercase and in the Courier font. An active High signal has no overbar. To
assert SIGNAL is to drive it High; to deassert SIGNAL is to drive it Low.
Numbers
X
An uppercase X indicates any of several values is allowed, where X can be any legal pattern. For
example, a binary value of 0X00 can be either 0100 or 0000, a hex value of 0xX is 0x0 or 0x1, and
so on.
0x
Hexadecimal numbers have a prefix of 0x. For example, 0x00FF is the hexadecimal number FF.
All other numbers within register tables are assumed to be binary. Within conceptual information,
binary numbers are indicated with a b suffix, for example, 1011b, and decimal numbers are written
without a prefix or suffix.
52
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
1
Architectural Overview
®
Texas Instruments is the industry leader in bringing 32-bit capabilities and the full benefits of ARM
Cortex™-M-based microcontrollers to the broadest reach of the microcontroller market. For current
®
users of 8- and 16-bit MCUs, Stellaris with Cortex-M offers a direct path to the strongest ecosystem
of development tools, software and knowledge in the industry. Designers who migrate to Stellaris
benefit from great tools, small code footprint and outstanding performance. Even more important,
designers can enter the ARM ecosystem with full confidence in a compatible roadmap from $1 to
1 GHz. For users of current 32-bit MCUs, the Stellaris family offers the industry’s first implementation
of Cortex-M3 and the Thumb-2 instruction set. With blazingly-fast responsiveness, Thumb-2
technology combines both 16-bit and 32-bit instructions to deliver the best balance of code density
and performance. Thumb-2 uses 26 percent less memory than pure 32-bit code to reduce system
cost while delivering 25 percent better performance. The Texas Instruments Stellaris family of
microcontrollers—the first ARM Cortex-M3 based controllers— brings high-performance 32-bit
computing to cost-sensitive embedded microcontroller applications.
1.1
Overview
The Stellaris LM3S5791 microcontroller combines complex integration and high performance with
the following feature highlights:
■ ARM Cortex-M3 Processor Core
■ High Performance: 80-MHz operation; 100 DMIPS performance
■ 128 KB single-cycle Flash memory
■ 64 KB single-cycle SRAM
®
■ Internal ROM loaded with StellarisWare software
■ External Peripheral Interface (EPI)
■ Advanced Communication Interfaces: UART, SSI, I2C, I2S, CAN, USB
■ System Integration: general-purpose timers, watchdog timers, DMA, general-purpose I/Os
■ Advanced motion control using PWMs, fault inputs, and quadrature encoder inputs
■ Analog support: analog and digital comparators, Analog-to-Digital Converters (ADC), on-chip
voltage regulator
■ JTAG and ARM Serial Wire Debug (SWD)
■ 100-pin LQFP package
■ 108-ball BGA package
■ Industrial (-40°C to 85°C) temperature range
Figure 1-1 on page 54 depicts the features on the Stellaris LM3S5791 microcontroller. Note that
there are two on-chip buses that connect the core to the peripherals. The Advanced Peripheral Bus
(APB) bus is the legacy bus. The Advanced High-Performance Bus (AHB) bus provides better
back-to-back access performance than the APB bus.
July 03, 2014
53
Texas Instruments-Production Data
Architectural Overview
Figure 1-1. Stellaris LM3S5791 Microcontroller High-Level Block Diagram
JTAG/SWD
ARM®
Cortex™-M3
ROM
(80MHz)
System
Control and
Clocks
(w/ Precis. Osc.)
DCode bus
NVIC
Boot Loader
DriverLib
AES & CRC
Flash
(128KB)
MPU
ICode bus
System Bus
LM3S5791
Bus Matrix
SRAM
(64KB)
SYSTEM PERIPHERALS
DMA
Watchdog
Timer
(2)
GPIOs
(72)
GeneralPurpose
Timer (4)
SSI
(2)
I2S
Advanced Peripheral Bus (APB)
USB OTG
(FS PHY)
Advanced High-Performance Bus (AHB)
External
Peripheral
Interface
SERIAL PERIPHERALS
UART
(3)
I2C
(2)
CAN
Controller
(2)
ANALOG PERIPHERALS
Analog
Comparator
(3)
10- Bit ADC
Channels
(16)
MOTION CONTROL PERIPHERALS
PWM
(8)
QEI
(2)
54
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
In addition, the LM3S5791 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 LM3S5791 microcontroller is code-compatible
to all members of the extensive Stellaris family; providing flexibility to fit precise needs.
Texas Instruments offers a complete solution to get to market quickly, with evaluation and
development boards, white papers and application notes, an easy-to-use peripheral driver library,
and a strong support, sales, and distributor network.
1.2
Target Applications
The Stellaris family is positioned for cost-conscious applications requiring significant control
processing and connectivity capabilities such as:
■
■
■
■
■
■
■
■
■
1.3
Gaming equipment
Home and commercial site monitoring and control
Motion control
Medical instrumentation
Test and measurement equipment
Factory automation
Fire and security
Lighting control
Transportation
Features
The LM3S5791 microcontroller component features and general function are discussed in more
detail in the following section.
1.3.1
ARM Cortex-M3 Processor Core
All members of the Stellaris product family, including the LM3S5791 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.
1.3.1.1
Processor Core (see page 75)
■ 32-bit ARM Cortex-M3 architecture optimized for small-footprint embedded applications
■ 80-MHz operation; 100 DMIPS performance
■ Outstanding processing performance combined with fast interrupt handling
■ Thumb-2 mixed 16-/32-bit instruction set delivers the high performance expected of a 32-bit
ARM core in a compact memory size usually associated with 8- and 16-bit devices, typically in
the range of a few kilobytes of memory for microcontroller-class applications
– Single-cycle multiply instruction and hardware divide
– Atomic bit manipulation (bit-banding), delivering maximum memory utilization and streamlined
peripheral control
July 03, 2014
55
Texas Instruments-Production Data
Architectural Overview
– Unaligned data access, enabling data to be efficiently packed into memory
■ Fast code execution permits slower processor clock or increases sleep mode time
■ Harvard architecture characterized by separate buses for instruction and data
■ Efficient processor core, system and memories
■ Hardware division and fast digital-signal-processing orientated multiply accumulate
■ Saturating arithmetic for signal processing
■ Deterministic, high-performance interrupt handling for time-critical applications
■ Memory protection unit (MPU) to provide a privileged mode for protected operating system
functionality
■ Enhanced system debug with extensive breakpoint and trace capabilities
■ Serial Wire Debug and Serial Wire Trace reduce the number of pins required for debugging and
tracing
■ Migration from the ARM7 processor family for better performance and power efficiency
■ Optimized for single-cycle Flash memory usage
■ Ultra-low power consumption with integrated sleep modes
1.3.1.2
System Timer (SysTick) (see page 118)
ARM 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 that fires at a programmable rate (for example, 100 Hz) and invokes a SysTick
routine
■ A high-speed alarm timer using the system clock
■ A variable rate alarm or signal timer—the duration is range-dependent on the reference clock
used and the dynamic range of the counter
■ A simple counter used to measure time to completion and time used
■ An internal clock-source control based on missing/meeting durations.
1.3.1.3
Nested Vectored Interrupt Controller (NVIC) (see page 119)
The LM3S5791 controller includes the ARM Nested Vectored Interrupt Controller (NVIC). The NVIC
and Cortex-M3 prioritize and handle all exceptions in Handler Mode. The processor state is
automatically stored to the stack on an exception and automatically restored from the stack at the
end of the Interrupt Service Routine (ISR). The interrupt vector is fetched in parallel to the state
saving, enabling efficient interrupt entry. The processor supports tail-chaining, meaning that
back-to-back interrupts can be performed without the overhead of state saving and restoration.
Software can set eight priority levels on 7 exceptions (system handlers) and 52 interrupts.
56
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ Deterministic, fast interrupt processing: always 12 cycles, or just 6 cycles with tail-chaining
■ External non-maskable interrupt signal (NMI) available for immediate execution of NMI handler
for safety critical applications
■ Dynamically reprioritizable interrupts
■ Exceptional interrupt handling via hardware implementation of required register manipulations
1.3.1.4
System Control Block (SCB) (see page 121)
The SCB provides system implementation information and system control, including configuration,
control, and reporting of system exceptions.
1.3.1.5
Memory Protection Unit (MPU) (see page 121)
The MPU supports the standard ARM7 Protected Memory System Architecture (PMSA) model. The
MPU provides full support for protection regions, overlapping protection regions, access permissions,
and exporting memory attributes to the system.
1.3.2
On-Chip Memory
The LM3S5791 microcontroller is integrated with the following set of on-chip memory and features:
■ 64 KB single-cycle SRAM
■ 128 KB single-cycle Flash memory up to 50 MHz; a prefetch buffer improves performance above
50 MHz
■ Internal ROM loaded with StellarisWare software:
– Stellaris Peripheral Driver Library
– Stellaris Boot Loader
– Advanced Encryption Standard (AES) cryptography tables
– Cyclic Redundancy Check (CRC) error detection functionality
1.3.2.1
SRAM (see page 302)
The LM3S5791 microcontroller provides 64 KB of single-cycle on-chip SRAM. The internal SRAM
of the Stellaris devices is located at offset 0x2000.0000 of the device memory map.
Because read-modify-write (RMW) operations are very time consuming, ARM has introduced
bit-banding technology in the Cortex-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.
Data can be transferred to and from the SRAM using the Micro Direct Memory Access Controller
(µDMA).
1.3.2.2
Flash Memory (see page 304)
The LM3S5791 microcontroller provides 128 KB of single-cycle on-chip Flash memory (above 50
MHz, the Flash memory can be accessed in a single cycle as long as the code is linear; branches
incur a one-cycle stall). The Flash memory is organized as a set of 1-KB blocks that can be
individually erased. Erasing a block causes the entire contents of the block to be reset to all 1s.
These blocks are paired into a set of 2-KB blocks that can be individually protected. The blocks can
be marked as read-only or execute-only, providing different levels of code protection. Read-only
blocks cannot be erased or programmed, protecting the contents of those blocks from being modified.
July 03, 2014
57
Texas Instruments-Production Data
Architectural Overview
Execute-only blocks cannot be erased or programmed, and can only be read by the controller
instruction fetch mechanism, protecting the contents of those blocks from being read by either the
controller or by a debugger.
1.3.2.3
ROM (see page 302)
The LM3S5791 ROM is preprogrammed with the following software and programs:
■ Stellaris Peripheral Driver Library
■ Stellaris Boot Loader
■ Advanced Encryption Standard (AES) cryptography tables
■ Cyclic Redundancy Check (CRC) error-detection functionality
The Stellaris Peripheral Driver Library is a royalty-free software library for controlling on-chip
peripherals with a boot-loader capability. The library performs both peripheral initialization and
control functions, with a choice of polled or interrupt-driven peripheral support. In addition, the library
is designed to take full advantage of the stellar interrupt performance of the ARM Cortex-M3 core.
No special pragmas or custom assembly code prologue/epilogue functions are required. For
applications that require in-field programmability, the royalty-free Stellaris Boot Loader can act as
an application loader and support in-field firmware updates.
The Advanced Encryption Standard (AES) is a publicly defined encryption standard used by the
U.S. Government. AES is a strong encryption method with reasonable performance and size. In
addition, it is fast in both hardware and software, is fairly easy to implement, and requires little
memory. The Texas Instruments encryption package is available with full source code, and is based
on lesser general public license (LGPL) source. An LGPL means that the code can be used within
an application without any copyleft implications for the application (the code does not automatically
become open source). Modifications to the package source, however, must be open source.
CRC (Cyclic Redundancy Check) is a technique to validate a span of data has the same contents
as when previously checked. This technique can be used to validate correct receipt of messages
(nothing lost or modified in transit), to validate data after decompression, to validate that Flash
memory contents have not been changed, and for other cases where the data needs to be validated.
A CRC is preferred over a simple checksum (e.g. XOR all bits) because it catches changes more
readily.
1.3.3
External Peripheral Interface (see page 453)
The External Peripheral Interface (EPI) provides access to external devices using a parallel path.
Unlike communications peripherals such as SSI, UART, and I2C, the EPI is designed to act like a
bus to external peripherals and memory.
The EPI has the following features:
■ 8/16/32-bit dedicated parallel bus for external peripherals and memory
■ Memory interface supports contiguous memory access independent of data bus width, thus
enabling code execution directly from SDRAM, SRAM and Flash memory
■ Blocking and non-blocking reads
■ Separates processor from timing details through use of an internal write FIFO
■ Efficient transfers using Micro Direct Memory Access Controller (µDMA)
58
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
– Separate channels for read and write
– Read channel request asserted by programmable levels on the internal non-blocking read
FIFO (NBRFIFO)
– Write channel request asserted by empty on the internal write FIFO (WFIFO)
The EPI supports three primary functional modes: Synchronous Dynamic Random Access Memory
(SDRAM) mode, Traditional Host-Bus mode, and General-Purpose mode. The EPI module also
provides custom GPIOs; however, unlike regular GPIOs, the EPI module uses a FIFO in the same
way as a communication mechanism and is speed-controlled using clocking.
■ Synchronous Dynamic Random Access Memory (SDRAM) mode
– Supports x16 (single data rate) SDRAM at up to 50 MHz
– Supports low-cost SDRAMs up to 64 MB (512 megabits)
– Includes automatic refresh and access to all banks/rows
– Includes a Sleep/Standby mode to keep contents active with minimal power draw
– Multiplexed address/data interface for reduced pin count
■ Host-Bus mode
– Traditional x8 and x16 MCU bus interface capabilities
– Similar device compatibility options as PIC, ATmega, 8051, and others
– Access to SRAM, NOR Flash memory, and other devices, with up to 1 MB of addressing in
unmultiplexed mode and 256 MB in multiplexed mode (512 MB in Host-Bus 16 mode with
no byte selects)
– Support of both muxed and de-muxed address and data
– Access to a range of devices supporting the non-address FIFO x8 and x16 interface variant,
with support for external FIFO (XFIFO) EMPTY and FULL signals
– Speed controlled, with read and write data wait-state counters
– Chip select modes include ALE, CSn, Dual CSn and ALE with dual CSn
– Manual chip-enable (or use extra address pins)
■ General-Purpose mode
– Wide parallel interfaces for fast communications with CPLDs and FPGAs
– Data widths up to 32 bits
– Data rates up to 150 MB/second
– Optional "address" sizes from 4 bits to 20 bits
July 03, 2014
59
Texas Instruments-Production Data
Architectural Overview
– Optional clock output, read/write strobes, framing (with counter-based size), and clock-enable
input
■ General parallel GPIO
– 1 to 32 bits, FIFOed with speed control
– Useful for custom peripherals or for digital data acquisition and actuator controls
1.3.4
Serial Communications Peripherals
The LM3S5791 controller supports both asynchronous and synchronous serial communications
with:
■ Two CAN 2.0 A/B controllers
■ USB 2.0 OTG/Host/Device
■ Three UARTs with IrDA and ISO 7816 support (one UART with modem flow control and status)
■ Two I2C modules
■ Two Synchronous Serial Interface modules (SSI)
■ Integrated Interchip Sound (I2S) module
The following sections provide more detail on each of these communications functions.
1.3.4.1
Controller Area Network (see page 859)
Controller Area Network (CAN) is a multicast shared serial-bus standard for connecting electronic
control units (ECUs). CAN was specifically designed to be robust in electromagnetically noisy
environments and can utilize a differential balanced line like RS-485 or twisted-pair wire. Originally
created for automotive purposes, it is now used in many embedded control applications (for example,
industrial or medical). Bit rates up to 1 Mbps are possible at network lengths below 40 meters.
Decreased bit rates allow longer network distances (for example, 125 Kbps at 500m).
A transmitter sends a message to all CAN nodes (broadcasting). Each node decides on the basis
of the identifier received whether it should process the message. The identifier also determines the
priority that the message enjoys in competition for bus access. Each CAN message can transmit
from 0 to 8 bytes of user information.
The LM3S5791 microcontroller includes two CAN units with the following features:
■ CAN protocol version 2.0 part A/B
■ Bit rates up to 1 Mbps
■ 32 message objects with individual identifier masks
■ Maskable interrupt
■ Disable Automatic Retransmission mode for Time-Triggered CAN (TTCAN) applications
■ Programmable Loopback mode for self-test operation
■ Programmable FIFO mode enables storage of multiple message objects
60
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ Gluelessly attaches to an external CAN transceiver through the CANnTX and CANnRX signals
1.3.4.2
USB (see page 910)
Universal Serial Bus (USB) is a serial bus standard designed to allow peripherals to be connected
and disconnected using a standardized interface without rebooting the system.
The LM3S5791 microcontroller supports three configurations in USB 2.0 full and low speed: USB
Device, USB Host, and USB On-The-Go (negotiated on-the-go as host or device when connected
to other USB-enabled systems).
The USB module has the following features:
■ Complies with USB-IF certification standards
■ USB 2.0 full-speed (12 Mbps) and low-speed (1.5 Mbps) operation with integrated PHY
■ 4 transfer types: Control, Interrupt, Bulk, and Isochronous
■ 32 endpoints
– 1 dedicated control IN endpoint and 1 dedicated control OUT endpoint
– 15 configurable IN endpoints and 15 configurable OUT endpoints
■ 4 KB dedicated endpoint memory: one endpoint may be defined for double-buffered 1023-byte
isochronous packet size
■ VBUS droop and valid ID detection and interrupt
■ Efficient transfers using Micro Direct Memory Access Controller (µDMA)
– Separate channels for transmit and receive for up to three IN endpoints and three OUT
endpoints
– Channel requests asserted when FIFO contains required amount of data
1.3.4.3
UART (see page 678)
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 LM3S5791 microcontroller includes three fully programmable 16C550-type UARTs. Although
the functionality is similar to a 16C550 UART, this UART design is not register compatible. The
UART can generate individually masked interrupts from the Rx, Tx, modem flow control, modem
status, and error conditions. The module generates a single combined interrupt when any of the
interrupts are asserted and are unmasked.
The three UARTs have the following features:
■ Programmable baud-rate generator allowing speeds up to 5 Mbps for regular speed (divide by
16) and 10 Mbps for high speed (divide by 8)
■ Separate 16x8 transmit (TX) and receive (RX) FIFOs to reduce CPU interrupt service loading
■ Programmable FIFO length, including 1-byte deep operation providing conventional
double-buffered interface
July 03, 2014
61
Texas Instruments-Production Data
Architectural Overview
■ FIFO trigger levels of 1/8, 1/4, 1/2, 3/4, and 7/8
■ Standard asynchronous communication bits for start, stop, and parity
■ Line-break generation and detection
■ Fully programmable serial interface characteristics
– 5, 6, 7, or 8 data bits
– Even, odd, stick, or no-parity bit generation/detection
– 1 or 2 stop bit generation
■ IrDA serial-IR (SIR) encoder/decoder providing
– Programmable use of IrDA Serial Infrared (SIR) or UART input/output
– Support of IrDA SIR encoder/decoder functions for data rates up to 115.2 Kbps half-duplex
– Support of normal 3/16 and low-power (1.41-2.23 μs) bit durations
– Programmable internal clock generator enabling division of reference clock by 1 to 256 for
low-power mode bit duration
■ Support for communication with ISO 7816 smart cards
■ Full modem handshake support (on UART1)
■ LIN protocol support
■ Standard FIFO-level and End-of-Transmission interrupts
■ Efficient transfers using Micro Direct Memory Access Controller (µDMA)
– Separate channels for transmit and receive
– Receive single request asserted when data is in the FIFO; burst request asserted at
programmed FIFO level
– Transmit single request asserted when there is space in the FIFO; burst request asserted at
programmed FIFO level
1.3.4.4
I2C (see page 784)
The Inter-Integrated Circuit (I2C) bus provides bi-directional data transfer through a two-wire design
(a serial data line SDA and a serial clock line SCL). The I2C bus interfaces to external I2C devices
such as serial memory (RAMs and ROMs), networking devices, LCDs, tone generators, and so on.
The I2C bus may also be used for system testing and diagnostic purposes in product development
and manufacture.
Each device on the I2C bus can be designated as either a master or a slave. Each I2C module
supports both sending and receiving data as either a master or a slave and can operate
simultaneously as both a master and a slave. Both the I2C master and slave can generate interrupts.
The LM3S5791 microcontroller includes two I2C modules with the following features:
62
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ Devices on the I2C bus can be designated as either a master or a slave
– Supports both transmitting and receiving data as either a master or a slave
– Supports simultaneous master and slave operation
■ Four I2C modes
– Master transmit
– Master receive
– Slave transmit
– Slave receive
■ Two transmission speeds: Standard (100 Kbps) and Fast (400 Kbps)
■ Master and slave interrupt generation
– Master generates interrupts when a transmit or receive operation completes (or aborts due
to an error)
– Slave generates interrupts when data has been transferred or requested by a master or when
a START or STOP condition is detected
■ Master with arbitration and clock synchronization, multimaster support, and 7-bit addressing
mode
1.3.4.5
SSI (see page 742)
Synchronous Serial Interface (SSI) is a four-wire bi-directional communications interface that converts
data between parallel and serial. The SSI module performs serial-to-parallel conversion on data
received from a peripheral device, and parallel-to-serial conversion on data transmitted to a peripheral
device. The SSI module can be configured as either a master or slave device. As a slave device,
the SSI module can also be configured to disable its output, which allows a master device to be
coupled with multiple slave devices. The TX and RX paths are buffered with separate internal FIFOs.
The SSI module also includes a programmable bit rate clock divider and prescaler to generate the
output serial clock derived from the SSI module's input clock. Bit rates are generated based on the
input clock and the maximum bit rate is determined by the connected peripheral.
The LM3S5791 microcontroller includes two SSI modules with the following features:
■ Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments
synchronous serial interfaces
■ Master or slave operation
■ Programmable clock bit rate and prescaler
■ Separate transmit and receive FIFOs, each 16 bits wide and 8 locations deep
■ Programmable data frame size from 4 to 16 bits
■ Internal loopback test mode for diagnostic/debug testing
July 03, 2014
63
Texas Instruments-Production Data
Architectural Overview
■ Standard FIFO-based interrupts and End-of-Transmission interrupt
■ Efficient transfers using Micro Direct Memory Access Controller (µDMA)
– Separate channels for transmit and receive
– Receive single request asserted when data is in the FIFO; burst request asserted when FIFO
contains 4 entries
– Transmit single request asserted when there is space in the FIFO; burst request asserted
when FIFO contains 4 entries
1.3.4.6
Inter-Integrated Circuit Sound (I2S) Interface (see page 822)
The I2S interface is a configurable serial audio core that contains a transmit module and a receive
module. The module is configurable for the I2S as well as Left-Justified and Right-Justified serial
audio formats. Data can be in one of four modes: Stereo, Mono, Compact 16-bit Stereo and Compact
8-Bit Stereo.
The transmit and receive modules each have an 8-entry audio-sample FIFO. An audio sample can
consist of a Left and Right Stereo sample, a Mono sample, or a Left and Right Compact Stereo
sample. In Compact 16-Bit Stereo, each FIFO entry contains both the 16-bit left and 16-bit right
samples, allowing efficient data transfers and requiring less memory space. In Compact 8-bit Stereo,
each FIFO entry contains an 8-bit left and an 8-bit right sample, reducing memory requirements
further.
Both the transmitter and receiver are capable of being a master or a slave.
The Stellaris I2S interface has the following features:
■ Configurable audio format supporting I2S, Left-justification, and Right-justification
■ Configurable sample size from 8 to 32 bits
■ Mono and Stereo support
■ 8-, 16-, and 32-bit FIFO interface for packing memory
■ Independent transmit and receive 8-entry FIFOs
■ Configurable FIFO-level interrupt and µDMA requests
■ Independent transmit and receive MCLK direction control
■ Transmit and receive internal MCLK sources
■ Independent transmit and receive control for serial clock and word select
■ MCLK and SCLK can be independently set to master or slave
■ Configurable transmit zero or last sample when FIFO empty
■ Efficient transfers using Micro Direct Memory Access Controller (µDMA)
– Separate channels for transmit and receive
– Burst requests
64
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
– Channel requests asserted when FIFO contains required amount of data
1.3.5
System Integration
The LM3S5791 microcontroller provides a variety of standard system functions integrated into the
device, including:
■ Direct Memory Access Controller (DMA)
■ System control and clocks including on-chip precision 16-MHz oscillator
■ Four 32-bit timers (up to eight 16-bit), with real-time clock capability
■ Eight Capture Compare PWM (CCP) pins
■ Two Watchdog Timers
– One timer runs off the main oscillator
– One timer runs off the precision internal oscillator
■ Up to 72 GPIOs, depending on configuration
– Highly flexible pin muxing allows use as GPIO or one of several peripheral functions
– Independently configurable to 2, 4 or 8 mA drive capability
– Up to 4 GPIOs can have 18 mA drive capability
The following sections provide more detail on each of these functions.
1.3.5.1
Direct Memory Access (see page 338)
The LM3S5791 microcontroller includes a Direct Memory Access (DMA) controller, known as
micro-DMA (μDMA). The μDMA controller provides a way to offload data transfer tasks from the
Cortex-M3 processor, allowing for more efficient use of the processor and the available bus
bandwidth. The μDMA controller can perform transfers between memory and peripherals. It has
dedicated channels for each supported on-chip module and can be programmed to automatically
perform transfers between peripherals and memory as the peripheral is ready to transfer more data.
The μDMA controller provides the following features:
®
■ ARM PrimeCell 32-channel configurable µDMA controller
■ Support for memory-to-memory, memory-to-peripheral, and peripheral-to-memory in multiple
transfer modes
– Basic for simple transfer scenarios
– Ping-pong for continuous data flow
– Scatter-gather for a programmable list of up to 256 arbitrary transfers initiated from a single
request
■ Highly flexible and configurable channel operation
– Independently configured and operated channels
– Dedicated channels for supported on-chip modules
– Primary and secondary channel assignments
July 03, 2014
65
Texas Instruments-Production Data
Architectural Overview
– One channel each for receive and transmit path for bidirectional modules
– Dedicated channel for software-initiated transfers
– Per-channel configurable priority scheme
– Optional software-initiated requests for any channel
■ Two levels of priority
■ Design optimizations for improved bus access performance between µDMA controller and the
processor core
– µDMA controller access is subordinate to core access
– RAM striping
– Peripheral bus segmentation
■ Data sizes of 8, 16, and 32 bits
■ Transfer size is programmable in binary steps from 1 to 1024
■ Source and destination address increment size of byte, half-word, word, or no increment
■ Maskable peripheral requests
1.3.5.2
System Control and Clocks (see page 196)
System control determines the overall operation of the device. It provides information about the
device, controls power-saving features, controls the clocking of the device and individual peripherals,
and handles reset detection and reporting.
■ Device identification information: version, part number, SRAM size, Flash memory size, and so
on
■ Power control
– On-chip fixed Low Drop-Out (LDO) voltage regulator
– Low-power options for microcontroller: Sleep and Deep-sleep modes with clock gating
– Low-power options for on-chip modules: software controls shutdown of individual peripherals
and memory
– 3.3-V supply brown-out detection and reporting via interrupt or reset
■ Multiple clock sources for microcontroller system clock
– Precision Oscillator (PIOSC): On-chip resource providing a 16 MHz ±1% frequency at room
temperature
• 16 MHz ±3% across temperature
• Can be recalibrated with 7-bit trim resolution
• Software power down control for low power modes
66
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
– Main Oscillator (MOSC): A frequency-accurate clock source by one of two means: an external
single-ended clock source is connected to the OSC0 input pin, or an external crystal is
connected across the OSC0 input and OSC1 output pins.
• External crystal used with or without on-chip PLL: select supported frequencies from 1
MHz to 16.384 MHz.
• External oscillator: from DC to maximum device speed
– Internal 30-kHz Oscillator: on chip resource providing a 30 kHz ± 50% frequency, used during
power-saving modes
■ Flexible reset sources
– Power-on reset (POR)
– Reset pin assertion
– Brown-out reset (BOR) detector alerts to system power drops
– Software reset
– Watchdog timer reset
– MOSC failure
1.3.5.3
Programmable Timers (see page 526)
Programmable timers can be used to count or time external events that drive the Timer input pins.
Each GPTM block provides two 16-bit timers/counters that can be configured to operate independently
as timers or event counters, or configured to operate as one 32-bit timer or one 32-bit Real-Time
Clock (RTC). Timers can also be used to trigger analog-to-digital (ADC) conversions.
The General-Purpose Timer Module (GPTM) contains four GPTM blocks with the following functional
options:
■ Operating modes:
– 16- or 32-bit programmable one-shot timer
– 16- or 32-bit programmable periodic timer
– 16-bit general-purpose timer with an 8-bit prescaler
– 32-bit Real-Time Clock (RTC) when using an external 32.768-KHz clock as the input
– 16-bit input-edge count- or time-capture modes
– 16-bit PWM mode with software-programmable output inversion of the PWM signal
■ Count up or down
■ Eight Capture Compare PWM pins (CCP)
■ Daisy chaining of timer modules to allow a single timer to initiate multiple timing events
■ ADC event trigger
July 03, 2014
67
Texas Instruments-Production Data
Architectural Overview
■ User-enabled stalling when the microcontroller asserts CPU Halt flag during debug (excluding
RTC mode)
■ Ability to determine the elapsed time between the assertion of the timer interrupt and entry into
the interrupt service routine.
■ Efficient transfers using Micro Direct Memory Access Controller (µDMA)
– Dedicated channel for each timer
– Burst request generated on timer interrupt
1.3.5.4
CCP Pins (see page 534)
Capture Compare PWM pins (CCP) can be used by the General-Purpose Timer Module to time/count
external events using the CCP pin as an input. Alternatively, the GPTM can generate a simple PWM
output on the CCP pin.
The LM3S5791 microcontroller includes eight Capture Compare PWM pins (CCP) that can be
programmed to operate in the following modes:
■ Capture: The GP Timer is incremented/decremented by programmed events on the CCP input.
The GP Timer captures and stores the current timer value when a programmed event occurs.
■ Compare: The GP Timer is incremented/decremented by programmed events on the CCP input.
The GP Timer compares the current value with a stored value and generates an interrupt when
a match occurs.
■ PWM: The GP Timer is incremented/decremented by the system clock. A PWM signal is generated
based on a match between the counter value and a value stored in a match register and is output
on the CCP pin.
1.3.5.5
Watchdog Timers (see page 573)
A watchdog timer is used to regain control when a system has failed due to a software error or to
the failure of an external device to respond in the expected way. The Stellaris Watchdog Timer can
generate an interrupt or a reset when a time-out value is reached. In addition, the Watchdog Timer
is ARM FiRM-compliant and can be configured to generate an interrupt to the microcontroller on its
first time-out, and to generate a reset signal on its second time-out. Once the Watchdog Timer has
been configured, the lock register can be written to prevent the timer configuration from being
inadvertently altered.
The LM3S5791 microcontroller has two Watchdog Timer modules: Watchdog Timer 0 uses the
system clock for its timer clock; Watchdog Timer 1 uses the PIOSC as its timer clock. The Stellaris
Watchdog Timer module has the following features:
■ 32-bit down counter with a programmable load register
■ Separate watchdog clock with an enable
■ Programmable interrupt generation logic with interrupt masking
■ Lock register protection from runaway software
■ Reset generation logic with an enable/disable
■ User-enabled stalling when the microcontroller asserts the CPU Halt flag during debug
68
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
1.3.5.6
Programmable GPIOs (see page 397)
General-purpose input/output (GPIO) pins offer flexibility for a variety of connections. The Stellaris
GPIO module is comprised of nine physical GPIO blocks, each corresponding to an individual GPIO
port. The GPIO module is FiRM-compliant (compliant to the ARM Foundation IP for Real-Time
Microcontrollers specification) and supports 0-72 programmable input/output pins. The number of
GPIOs available depends on the peripherals being used (see “Signal Tables” on page 1166 for the
signals available to each GPIO pin).
■ Up to 72 GPIOs, depending on configuration
■ Highly flexible pin muxing allows use as GPIO or one of several peripheral functions
■ 5-V-tolerant in input configuration
■ Two means of port access: either Advanced High-Performance Bus (AHB) with better back-to-back
access performance, or the legacy Advanced Peripheral Bus (APB) for backwards-compatibility
with existing code
■ Fast toggle capable of a change every clock cycle for ports on AHB, every two clock cycles for
ports on APB
■ Programmable control for GPIO interrupts
– Interrupt generation masking
– Edge-triggered on rising, falling, or both
– Level-sensitive on High or Low values
■ Bit masking in both read and write operations through address lines
■ Can be used to initiate an ADC sample sequence
■ Pins configured as digital inputs are Schmitt-triggered
■ Programmable control for GPIO pad configuration
– Weak pull-up or pull-down resistors
– 2-mA, 4-mA, and 8-mA pad drive for digital communication; up to four pads can sink 18-mA
for high-current applications
– Slew rate control for the 8-mA drive
– Open drain enables
– Digital input enables
1.3.6
Advanced Motion Control
The LM3S5791 microcontroller provides motion control functions integrated into the device, including:
■ Eight advanced PWM outputs for motion and energy applications
■ Four fault inputs to promote low-latency shutdown
July 03, 2014
69
Texas Instruments-Production Data
Architectural Overview
■ Two Quadrature Encoder Inputs (QEI)
The following provides more detail on these motion control functions.
1.3.6.1
PWM (see page 1063)
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. The LM3S5791 PWM module consists of four PWM generator blocks and a
control block. Each PWM generator block contains one timer (16-bit down or up/down counter), two
comparators, a PWM signal generator, a dead-band generator, and an interrupt/ADC-trigger selector.
Each PWM generator block produces two PWM signals that can either be independent signals or
a single pair of complementary signals with dead-band delays inserted.
Each PWM generator has the following features:
■ Four fault-condition handling inputs to quickly provide low-latency shutdown and prevent damage
to the motor being controlled
■ One 16-bit counter
– Runs in Down or Up/Down mode
– Output frequency controlled by a 16-bit load value
– Load value updates can be synchronized
– Produces output signals at zero and load value
■ Two PWM comparators
– Comparator value updates can be synchronized
– Produces output signals on match
■ PWM signal generator
– Output PWM signal is constructed based on actions taken as a result of the counter and
PWM comparator output signals
– Produces two independent PWM signals
■ Dead-band generator
– Produces two PWM signals with programmable dead-band delays suitable for driving a half-H
bridge
– Can be bypassed, leaving input PWM signals unmodified
■ Can initiate an ADC sample sequence
The control block determines the polarity of the PWM signals and which signals are passed through
to the pins. The output of the PWM generation blocks are managed by the output control block
before being passed to the device pins. The PWM control block has the following options:
■ PWM output enable of each PWM signal
70
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ Optional output inversion of each PWM signal (polarity control)
■ Optional fault handling for each PWM signal
■ Synchronization of timers in the PWM generator blocks
■ Synchronization of timer/comparator updates across the PWM generator blocks
■ Extended PWM synchronization of timer/comparator updates across the PWM generator blocks
■ Interrupt status summary of the PWM generator blocks
■ Extended PWM fault handling, with multiple fault signals, programmable polarities, and filtering
■ PWM generators can be operated independently or synchronized with other generators
1.3.6.2
QEI (see page 1141)
A quadrature encoder, also known as a 2-channel incremental encoder, converts linear displacement
into a pulse signal. By monitoring both the number of pulses and the relative phase of the two signals,
the position, direction of rotation, and speed can be tracked. In addition, a third channel, or index
signal, can be used to reset the position counter. The Stellaris quadrature encoder with index (QEI)
module interprets the code produced by a quadrature encoder wheel to integrate position over time
and determine direction of rotation. In addition, it can capture a running estimate of the velocity of
the encoder wheel. The input frequency of the QEI inputs may be as high as 1/4 of the processor
frequency (for example, 20 MHz for a 80-MHz system).
The LM3S5791 microcontroller includes two QEI modules providing control of two motors at the
same time with the following features:
■ Position integrator that tracks the encoder position
■ Programmable noise filter on the inputs
■ Velocity capture using built-in timer
■ The input frequency of the QEI inputs may be as high as 1/4 of the processor frequency (for
example, 12.5 MHz for a 50-MHz system)
■ Interrupt generation on:
– Index pulse
– Velocity-timer expiration
– Direction change
– Quadrature error detection
1.3.7
Analog
The LM3S5791 microcontroller provides analog functions integrated into the device, including:
■ Two 10-bit Analog-to-Digital Converters (ADC) with 16 analog input channels and a sample rate
of one million samples/second
■ Three analog comparators
July 03, 2014
71
Texas Instruments-Production Data
Architectural Overview
■ 16 digital comparators
■ On-chip voltage regulator
The following provides more detail on these analog functions.
1.3.7.1
ADC (see page 598)
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
16 input channels plus an internal temperature sensor. Four buffered sample sequencers allow
rapid sampling of up to 16 analog input sources without controller intervention. Each sample
sequencer provides flexible programming with fully configurable input source, trigger events, interrupt
generation, and sequencer priority. Each ADC module has a digital comparator function that allows
the conversion value to be diverted to a comparison unit that provides eight digital comparators.
The LM3S5791 microcontroller provides two ADC modules with the following features:
■ 16 shared analog input channels
■ Single-ended and differential-input configurations
■ On-chip internal temperature sensor
■ Maximum sample rate of one million samples/second
■ Optional phase shift in sample time programmable from 22.5º to 337.5º
■ Four programmable sample conversion sequencers from one to eight entries long, with
corresponding conversion result FIFOs
■ Flexible trigger control
– Controller (software)
– Timers
– Analog Comparators
– PWM
– GPIO
■ Hardware averaging of up to 64 samples
■ Digital comparison unit providing eight digital comparators
■ Converter uses an internal 3-V reference or an external reference
■ Power and ground for the analog circuitry is separate from the digital power and ground
■ Efficient transfers using Micro Direct Memory Access Controller (µDMA)
– Dedicated channel for each sample sequencer
– ADC module uses burst requests for DMA
72
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
1.3.7.2
Analog Comparators (see page 1049)
An analog comparator is a peripheral that compares two analog voltages and provides a logical
output that signals the comparison result. The LM3S5791 microcontroller provides three independent
integrated analog comparators that can be configured to drive an output or generate an interrupt or
ADC event.
The comparator can provide its output to a device pin, acting as a replacement for an analog
comparator on the board, or it can be used to signal the application via interrupts or triggers to the
ADC to cause it to start capturing a sample sequence. The interrupt generation and ADC triggering
logic is separate. This means, for example, that an interrupt can be generated on a rising edge and
the ADC triggered on a falling edge.
The LM3S5791 microcontroller provides three independent integrated analog comparators with the
following functions:
■ Compare external pin input to external pin input or to internal programmable voltage reference
■ Compare a test voltage against any one of the following voltages:
– An individual external reference voltage
– A shared single external reference voltage
– A shared internal reference voltage
1.3.8
JTAG and ARM Serial Wire Debug (see page 184)
The Joint Test Action Group (JTAG) port is an IEEE standard that defines a Test Access Port and
Boundary Scan Architecture for digital integrated circuits and provides a standardized serial interface
for controlling the associated test logic. The TAP, Instruction Register (IR), and Data Registers (DR)
can be used to test the interconnections of assembled printed circuit boards and obtain manufacturing
information on the components. The JTAG Port also provides a means of accessing and controlling
design-for-test features such as I/O pin observation and control, scan testing, and debugging. Texas
Instruments replaces the ARM SW-DP and JTAG-DP with the ARM Serial Wire JTAG Debug Port
(SWJ-DP) interface. The SWJ-DP interface combines the SWD and JTAG debug ports into one
module providing all the normal JTAG debug and test functionality plus real-time access to system
memory without halting the core or requiring any target resident code. The SWJ-DP interface has
the following features:
■ IEEE 1149.1-1990 compatible Test Access Port (TAP) controller
■ Four-bit Instruction Register (IR) chain for storing JTAG instructions
■ IEEE standard instructions: BYPASS, IDCODE, SAMPLE/PRELOAD, EXTEST and INTEST
■ ARM additional instructions: APACC, DPACC and ABORT
■ Integrated ARM Serial Wire Debug (SWD)
– Serial Wire JTAG Debug Port (SWJ-DP)
– Flash Patch and Breakpoint (FPB) unit for implementing breakpoints
– Data Watchpoint and Trace (DWT) unit for implementing watchpoints, trigger resources, and
system profiling
July 03, 2014
73
Texas Instruments-Production Data
Architectural Overview
– Instrumentation Trace Macrocell (ITM) for support of printf style debugging
– Trace Port Interface Unit (TPIU) for bridging to a Trace Port Analyzer
1.3.9
Packaging and Temperature
■ Industrial-range (-40°C to 85°C) 100-pin RoHS-compliant LQFP package
■ Industrial-range (-40°C to 85°C) 108-ball RoHS-compliant BGA package
1.4
Hardware Details
Details on the pins and package can be found in the following sections:
■ “Pin Diagram” on page 1164
■ “Signal Tables” on page 1166
■ “Operating Characteristics” on page 1246
■ “Electrical Characteristics” on page 1247
■ “Package Information” on page 1325
74
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
2
The Cortex-M3 Processor
The ARM® Cortex™-M3 processor provides a high-performance, low-cost platform that meets the
system requirements of minimal memory implementation, reduced pin count, and low power
consumption, while delivering outstanding computational performance and exceptional system
response to interrupts. Features include:
®
■ 32-bit ARM Cortex™-M3 architecture optimized for small-footprint embedded applications
■ 80-MHz operation; 100 DMIPS performance
■ Outstanding processing performance combined with fast interrupt handling
■ Thumb-2 mixed 16-/32-bit instruction set delivers the high performance expected of a 32-bit
ARM core in a compact memory size usually associated with 8- and 16-bit devices, typically in
the range of a few kilobytes of memory for microcontroller-class applications
– Single-cycle multiply instruction and hardware divide
– Atomic bit manipulation (bit-banding), delivering maximum memory utilization and streamlined
peripheral control
– Unaligned data access, enabling data to be efficiently packed into memory
■ Fast code execution permits slower processor clock or increases sleep mode time
■ Harvard architecture characterized by separate buses for instruction and data
■ Efficient processor core, system and memories
■ Hardware division and fast digital-signal-processing orientated multiply accumulate
■ Saturating arithmetic for signal processing
■ Deterministic, high-performance interrupt handling for time-critical applications
■ Memory protection unit (MPU) to provide a privileged mode for protected operating system
functionality
■ Enhanced system debug with extensive breakpoint and trace capabilities
■ Serial Wire Debug and Serial Wire Trace reduce the number of pins required for debugging and
tracing
■ Migration from the ARM7 processor family for better performance and power efficiency
■ Optimized for single-cycle Flash memory usage
■ Ultra-low power consumption with integrated sleep modes
®
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 motor control.
July 03, 2014
75
Texas Instruments-Production Data
The Cortex-M3 Processor
This chapter provides information on the Stellaris implementation of the Cortex-M3 processor,
including the programming model, the memory model, the exception model, fault handling, and
power management.
For technical details on the instruction set, see the Cortex™-M3/M4 Instruction Set Technical User's
Manual.
2.1
Block Diagram
The Cortex-M3 processor is built on a high-performance processor core, with a 3-stage pipeline
Harvard architecture, making it ideal for demanding embedded applications. The processor delivers
exceptional power efficiency through an efficient instruction set and extensively optimized design,
providing high-end processing hardware including a range of single-cycle and SIMD multiplication
and multiply-with-accumulate capabilities, saturating arithmetic and dedicated hardware division.
To facilitate the design of cost-sensitive devices, the Cortex-M3 processor implements tightly coupled
system components that reduce processor area while significantly improving interrupt handling and
system debug capabilities. The Cortex-M3 processor implements a version of the Thumb® instruction
set based on Thumb-2 technology, ensuring high code density and reduced program memory
requirements. The Cortex-M3 instruction set provides the exceptional performance expected of a
modern 32-bit architecture, with the high code density of 8-bit and 16-bit microcontrollers.
The Cortex-M3 processor closely integrates a nested interrupt controller (NVIC), to deliver
industry-leading interrupt performance. The Stellaris NVIC includes a non-maskable interrupt (NMI)
and provides eight interrupt priority levels. The tight integration of the processor core and NVIC
provides fast execution of interrupt service routines (ISRs), dramatically reducing interrupt latency.
The hardware stacking of registers and the ability to suspend load-multiple and store-multiple
operations further reduce interrupt latency. Interrupt handlers do not require any assembler stubs
which removes code overhead from the ISRs. Tail-chaining optimization also significantly reduces
the overhead when switching from one ISR to another. To optimize low-power designs, the NVIC
integrates with the sleep modes, including Deep-sleep mode, which enables the entire device to be
rapidly powered down.
76
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 2-1. CPU Block Diagram
Nested
Vectored
Interrupt
Controller
Interrupts
Sleep
ARM
Cortex-M3
CM3 Core
Debug
Instructions
Data
Trace
Port
Interface
Unit
Memory
Protection
Unit
Flash
Patch and
Breakpoint
Instrumentation
Data
Watchpoint Trace Macrocell
and Trace
ROM
Table
Private Peripheral
Bus
(internal)
Adv. Peripheral
Bus
Bus
Matrix
Serial Wire JTAG
Debug Port
Debug
Access Port
2.2
Overview
2.2.1
System-Level Interface
Serial
Wire
Output
Trace
Port
(SWO)
I-code bus
D-code bus
System bus
The Cortex-M3 processor provides multiple interfaces using AMBA® technology to provide
high-speed, low-latency memory accesses. The core supports unaligned data accesses and
implements atomic bit manipulation that enables faster peripheral controls, system spinlocks, and
thread-safe Boolean data handling.
The Cortex-M3 processor has a memory protection unit (MPU) that provides fine-grain memory
control, enabling applications to implement security privilege levels and separate code, data and
stack on a task-by-task basis.
2.2.2
Integrated Configurable Debug
The Cortex-M3 processor implements a complete hardware debug solution, providing high system
visibility of the processor and memory through either a traditional JTAG port or a 2-pin Serial Wire
Debug (SWD) port that is ideal for microcontrollers and other small package devices. The Stellaris
implementation replaces the ARM SW-DP and JTAG-DP with the ARM CoreSight™-compliant
Serial Wire JTAG Debug Port (SWJ-DP) interface. The SWJ-DP interface combines the SWD and
JTAG debug ports into one module. See the ARM® Debug Interface V5 Architecture Specification
for details on SWJ-DP.
For system trace, the processor integrates an Instrumentation Trace Macrocell (ITM) alongside data
watchpoints and a profiling unit. To enable simple and cost-effective profiling of the system trace
events, a Serial Wire Viewer (SWV) can export a stream of software-generated messages, data
trace, and profiling information through a single pin.
July 03, 2014
77
Texas Instruments-Production Data
The Cortex-M3 Processor
The Flash Patch and Breakpoint Unit (FPB) provides up to eight hardware breakpoint comparators
that debuggers can use. The comparators in the FPB also provide remap functions of up to eight
words in the program code in the CODE memory region. This enables applications stored in a
read-only area of Flash memory to be patched in another area of on-chip SRAM or Flash memory.
If a patch is required, the application programs the FPB to remap a number of addresses. When
those addresses are accessed, the accesses are redirected to a remap table specified in the FPB
configuration.
For more information on the Cortex-M3 debug capabilities, see theARM® Debug Interface V5
Architecture Specification.
2.2.3
Trace Port Interface Unit (TPIU)
The TPIU acts as a bridge between the Cortex-M3 trace data from the ITM, and an off-chip Trace
Port Analyzer, as shown in Figure 2-2 on page 78.
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)
Cortex-M3 System Component Details
The Cortex-M3 includes the following system components:
■ SysTick
A 24-bit count-down timer that can be used as a Real-Time Operating System (RTOS) tick timer
or as a simple counter (see “System Timer (SysTick)” on page 118).
■ Nested Vectored Interrupt Controller (NVIC)
An embedded interrupt controller that supports low latency interrupt processing (see “Nested
Vectored Interrupt Controller (NVIC)” on page 119).
■ System Control Block (SCB)
78
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
The programming model interface to the processor. The SCB provides system implementation
information and system control, including configuration, control, and reporting of system exceptions
(see “System Control Block (SCB)” on page 121).
■ Memory Protection Unit (MPU)
Improves system reliability by defining the memory attributes for different memory regions. The
MPU provides up to eight different regions and an optional predefined background region (see
“Memory Protection Unit (MPU)” on page 121).
2.3
Programming Model
This section describes the Cortex-M3 programming model. In addition to the individual core register
descriptions, information about the processor modes and privilege levels for software execution and
stacks is included.
2.3.1
Processor Mode and Privilege Levels for Software Execution
The Cortex-M3 has two modes of operation:
■ Thread mode
Used to execute application software. The processor enters Thread mode when it comes out of
reset.
■ Handler mode
Used to handle exceptions. When the processor has finished exception processing, it returns to
Thread mode.
In addition, the Cortex-M3 has two privilege levels:
■ Unprivileged
In this mode, software has the following restrictions:
– Limited access to the MSR and MRS instructions and no use of the CPS instruction
– No access to the system timer, NVIC, or system control block
– Possibly restricted access to memory or peripherals
■ Privileged
In this mode, software can use all the instructions and has access to all resources.
In Thread mode, the CONTROL register (see page 93) controls whether software execution is
privileged or unprivileged. In Handler mode, software execution is always privileged.
Only privileged software can write to the CONTROL register to change the privilege level for software
execution in Thread mode. Unprivileged software can use the SVC instruction to make a supervisor
call to transfer control to privileged software.
2.3.2
Stacks
The processor uses a full descending stack, meaning that the stack pointer indicates the last stacked
item on the memory. When the processor pushes a new item onto the stack, it decrements the stack
pointer and then writes the item to the new memory location. The processor implements two stacks:
July 03, 2014
79
Texas Instruments-Production Data
The Cortex-M3 Processor
the main stack and the process stack, with a pointer for each held in independent registers (see the
SP register on page 83).
In Thread mode, the CONTROL register (see page 93) controls whether the processor uses the
main stack or the process stack. In Handler mode, the processor always uses the main stack. The
options for processor operations are shown in Table 2-1 on page 80.
Table 2-1. Summary of Processor Mode, Privilege Level, and Stack Use
Processor Mode
Use
Privilege Level
Thread
Applications
Privileged or unprivileged
Stack Used
Handler
Exception handlers
Always privileged
a
Main stack or process stack
a
Main stack
a. See CONTROL (page 93).
2.3.3
Register Map
Figure 2-3 on page 80 shows the Cortex-M3 register set. Table 2-2 on page 81 lists the Core
registers. The core registers are not memory mapped and are accessed by register name, so the
base address is n/a (not applicable) and there is no offset.
Figure 2-3. Cortex-M3 Register Set
R0
R1
R2
Low registers
R3
R4
R5
R6
General-purpose registers
R7
R8
R9
High registers
R10
R11
R12
Stack Pointer
SP (R13)
Link Register
LR (R14)
Program Counter
PC (R15)
PSR
PSP‡
MSP‡
‡
Banked version of SP
Program status register
PRIMASK
FAULTMASK
Exception mask registers
Special registers
BASEPRI
CONTROL
CONTROL register
80
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 2-2. Processor Register Map
Offset
Type
Reset
-
R0
R/W
-
Cortex General-Purpose Register 0
82
-
R1
R/W
-
Cortex General-Purpose Register 1
82
-
R2
R/W
-
Cortex General-Purpose Register 2
82
-
R3
R/W
-
Cortex General-Purpose Register 3
82
-
R4
R/W
-
Cortex General-Purpose Register 4
82
-
R5
R/W
-
Cortex General-Purpose Register 5
82
-
R6
R/W
-
Cortex General-Purpose Register 6
82
-
R7
R/W
-
Cortex General-Purpose Register 7
82
-
R8
R/W
-
Cortex General-Purpose Register 8
82
-
R9
R/W
-
Cortex General-Purpose Register 9
82
-
R10
R/W
-
Cortex General-Purpose Register 10
82
-
R11
R/W
-
Cortex General-Purpose Register 11
82
-
R12
R/W
-
Cortex General-Purpose Register 12
82
-
SP
R/W
-
Stack Pointer
83
-
LR
R/W
0xFFFF.FFFF
Link Register
84
-
PC
R/W
-
Program Counter
85
-
PSR
R/W
0x0100.0000
Program Status Register
86
-
PRIMASK
R/W
0x0000.0000
Priority Mask Register
90
-
FAULTMASK
R/W
0x0000.0000
Fault Mask Register
91
-
BASEPRI
R/W
0x0000.0000
Base Priority Mask Register
92
-
CONTROL
R/W
0x0000.0000
Control Register
93
2.3.4
Description
See
page
Name
Register Descriptions
This section lists and describes the Cortex-M3 registers, in the order shown in Figure 2-3 on page 80.
The core registers are not memory mapped and are accessed by register name rather than offset.
Note:
The register type shown in the register descriptions refers to type during program execution
in Thread mode and Handler mode. Debug access can differ.
July 03, 2014
81
Texas Instruments-Production Data
The Cortex-M3 Processor
Register 1: Cortex General-Purpose Register 0 (R0)
Register 2: Cortex General-Purpose Register 1 (R1)
Register 3: Cortex General-Purpose Register 2 (R2)
Register 4: Cortex General-Purpose Register 3 (R3)
Register 5: Cortex General-Purpose Register 4 (R4)
Register 6: Cortex General-Purpose Register 5 (R5)
Register 7: Cortex General-Purpose Register 6 (R6)
Register 8: Cortex General-Purpose Register 7 (R7)
Register 9: Cortex General-Purpose Register 8 (R8)
Register 10: Cortex General-Purpose Register 9 (R9)
Register 11: Cortex General-Purpose Register 10 (R10)
Register 12: Cortex General-Purpose Register 11 (R11)
Register 13: Cortex General-Purpose Register 12 (R12)
The Rn registers are 32-bit general-purpose registers for data operations and can be accessed
from either privileged or unprivileged mode.
Cortex General-Purpose Register 0 (R0)
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
DATA
Type
Reset
DATA
Type
Reset
Bit/Field
Name
Type
Reset
31:0
DATA
R/W
-
Description
Register data.
82
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 14: Stack Pointer (SP)
The Stack Pointer (SP) is register R13. In Thread mode, the function of this register changes
depending on the ASP bit in the Control Register (CONTROL) register. When the ASP bit is clear,
this register is the Main Stack Pointer (MSP). When the ASP bit is set, this register is the Process
Stack Pointer (PSP). On reset, the ASP bit is clear, and the processor loads the MSP with the value
from address 0x0000.0000. The MSP can only be accessed in privileged mode; the PSP can be
accessed in either privileged or unprivileged mode.
Stack Pointer (SP)
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
SP
Type
Reset
SP
Type
Reset
Bit/Field
Name
Type
Reset
31:0
SP
R/W
-
Description
This field is the address of the stack pointer.
July 03, 2014
83
Texas Instruments-Production Data
The Cortex-M3 Processor
Register 15: Link Register (LR)
The Link Register (LR) is register R14, and it stores the return information for subroutines, function
calls, and exceptions. LR can be accessed from either privileged or unprivileged mode.
EXC_RETURN is loaded into LR on exception entry. See Table 2-10 on page 111 for the values and
description.
Link Register (LR)
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
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
LINK
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
15
14
13
12
11
10
9
8
LINK
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
Bit/Field
Name
Type
31:0
LINK
R/W
R/W
1
Reset
R/W
1
Description
0xFFFF.FFFF This field is the return address.
84
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 16: Program Counter (PC)
The Program Counter (PC) is register R15, and it contains the current program address. On reset,
the processor loads the PC with the value of the reset vector, which is at address 0x0000.0004. Bit
0 of the reset vector is loaded into the THUMB bit of the EPSR at reset and must be 1. The PC register
can be accessed in either privileged or unprivileged mode.
Program Counter (PC)
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
PC
Type
Reset
PC
Type
Reset
Bit/Field
Name
Type
Reset
31:0
PC
R/W
-
Description
This field is the current program address.
July 03, 2014
85
Texas Instruments-Production Data
The Cortex-M3 Processor
Register 17: Program Status Register (PSR)
Note:
This register is also referred to as xPSR.
The Program Status Register (PSR) has three functions, and the register bits are assigned to the
different functions:
■ Application Program Status Register (APSR), bits 31:27,
■ Execution Program Status Register (EPSR), bits 26:24, 15:10
■ Interrupt Program Status Register (IPSR), bits 6:0
The PSR, IPSR, and EPSR registers can only be accessed in privileged mode; the APSR register
can be accessed in either privileged or unprivileged mode.
APSR contains the current state of the condition flags from previous instruction executions.
EPSR contains the Thumb state bit and the execution state bits for the If-Then (IT) instruction or
the Interruptible-Continuable Instruction (ICI) field for an interrupted load multiple or store multiple
instruction. Attempts to read the EPSR directly through application software using the MSR instruction
always return zero. Attempts to write the EPSR using the MSR instruction in application software
are always ignored. Fault handlers can examine the EPSR value in the stacked PSR to determine
the operation that faulted (see “Exception Entry and Return” on page 109).
IPSR contains the exception type number of the current Interrupt Service Routine (ISR).
These registers can be accessed individually or as a combination of any two or all three registers,
using the register name as an argument to the MSR or MRS instructions. For example, all of the
registers can be read using PSR with the MRS instruction, or APSR only can be written to using
APSR with the MSR instruction. page 86 shows the possible register combinations for the PSR. See
the MRS and MSR instruction descriptions in the Cortex™-M3/M4 Instruction Set Technical User's
Manual for more information about how to access the program status registers.
Table 2-3. PSR Register Combinations
Register
Type
PSR
R/W
Combination
APSR, EPSR, and IPSR
IEPSR
RO
EPSR and IPSR
a, b
a
APSR and IPSR
b
APSR and EPSR
IAPSR
R/W
EAPSR
R/W
a. The processor ignores writes to the IPSR bits.
b. Reads of the EPSR bits return zero, and the processor ignores writes to these bits.
Program Status Register (PSR)
Type R/W, reset 0x0100.0000
Type
Reset
31
30
29
28
27
N
Z
C
V
Q
26
25
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
RO
0
RO
0
15
14
13
12
11
10
9
ICI / IT
ICI / IT
Type
Reset
RO
0
RO
0
RO
0
24
23
22
21
20
THUMB
RO
1
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
reserved
RO
0
RO
0
RO
0
RO
0
RO
0
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
reserved
ISRNUM
RO
0
RO
0
86
RO
0
RO
0
RO
0
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
31
N
R/W
0
Description
APSR Negative or Less Flag
Value Description
1
The previous operation result was negative or less than.
0
The previous operation result was positive, zero, greater than,
or equal.
The value of this bit is only meaningful when accessing PSR or APSR.
30
Z
R/W
0
APSR Zero Flag
Value Description
1
The previous operation result was zero.
0
The previous operation result was non-zero.
The value of this bit is only meaningful when accessing PSR or APSR.
29
C
R/W
0
APSR Carry or Borrow Flag
Value Description
1
The previous add operation resulted in a carry bit or the previous
subtract operation did not result in a borrow bit.
0
The previous add operation did not result in a carry bit or the
previous subtract operation resulted in a borrow bit.
The value of this bit is only meaningful when accessing PSR or APSR.
28
V
R/W
0
APSR Overflow Flag
Value Description
1
The previous operation resulted in an overflow.
0
The previous operation did not result in an overflow.
The value of this bit is only meaningful when accessing PSR or APSR.
27
Q
R/W
0
APSR DSP Overflow and Saturation Flag
Value Description
1
DSP Overflow or saturation has occurred.
0
DSP overflow or saturation has not occurred since reset or since
the bit was last cleared.
The value of this bit is only meaningful when accessing PSR or APSR.
This bit is cleared by software using an MRS instruction.
July 03, 2014
87
Texas Instruments-Production Data
The Cortex-M3 Processor
Bit/Field
Name
Type
Reset
26:25
ICI / IT
RO
0x0
Description
EPSR ICI / IT status
These bits, along with bits 15:10, contain the Interruptible-Continuable
Instruction (ICI) field for an interrupted load multiple or store multiple
instruction or the execution state bits of the IT instruction.
When EPSR holds the ICI execution state, bits 26:25 are zero.
The If-Then block contains up to four instructions following an IT
instruction. Each instruction in the block is conditional. The conditions
for the instructions are either all the same, or some can be the inverse
of others. See the Cortex™-M3/M4 Instruction Set Technical User's
Manual for more information.
The value of this field is only meaningful when accessing PSR or EPSR.
24
THUMB
RO
1
EPSR Thumb State
This bit indicates the Thumb state and should always be set.
The following can clear the THUMB bit:
■
The BLX, BX and POP{PC} instructions
■
Restoration from the stacked xPSR value on an exception return
■
Bit 0 of the vector value on an exception entry or reset
Attempting to execute instructions when this bit is clear results in a fault
or lockup. See “Lockup” on page 113 for more information.
The value of this bit is only meaningful when accessing PSR or EPSR.
23:16
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.
15:10
ICI / IT
RO
0x0
EPSR ICI / IT status
These bits, along with bits 26:25, contain the Interruptible-Continuable
Instruction (ICI) field for an interrupted load multiple or store multiple
instruction or the execution state bits of the IT instruction.
When an interrupt occurs during the execution of an LDM, STM, PUSH
or POP instruction, the processor stops the load multiple or store multiple
instruction operation temporarily and stores the next register operand
in the multiple operation to bits 15:12. After servicing the interrupt, the
processor returns to the register pointed to by bits 15:12 and resumes
execution of the multiple load or store instruction. When EPSR holds
the ICI execution state, bits 11:10 are zero.
The If-Then block contains up to four instructions following a 16-bit IT
instruction. Each instruction in the block is conditional. The conditions
for the instructions are either all the same, or some can be the inverse
of others. See the Cortex™-M3/M4 Instruction Set Technical User's
Manual for more information.
The value of this field is only meaningful when accessing PSR or EPSR.
9:7
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.
88
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
6:0
ISRNUM
RO
0x00
IPSR ISR Number
This field contains the exception type number of the current Interrupt
Service Routine (ISR).
Value
Description
0x00
Thread mode
0x01
Reserved
0x02
NMI
0x03
Hard fault
0x04
Memory management fault
0x05
Bus fault
0x06
Usage fault
0x07-0x0A Reserved
0x0B
SVCall
0x0C
Reserved for Debug
0x0D
Reserved
0x0E
PendSV
0x0F
SysTick
0x10
Interrupt Vector 0
0x11
Interrupt Vector 1
...
...
0x46
Interrupt Vector 54
0x47-0x7F Reserved
See “Exception Types” on page 104 for more information.
The value of this field is only meaningful when accessing PSR or IPSR.
July 03, 2014
89
Texas Instruments-Production Data
The Cortex-M3 Processor
Register 18: Priority Mask Register (PRIMASK)
The PRIMASK register prevents activation of all exceptions with programmable priority. Reset,
non-maskable interrupt (NMI), and hard fault are the only exceptions with fixed priority. Exceptions
should be disabled when they might impact the timing of critical tasks. This register is only accessible
in privileged mode. The MSR and MRS instructions are used to access the PRIMASK register, and
the CPS instruction may be used to change the value of the PRIMASK register. See the
Cortex™-M3/M4 Instruction Set Technical User's Manual for more information on these instructions.
For more information on exception priority levels, see “Exception Types” on page 104.
Priority Mask Register (PRIMASK)
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
Bit/Field
Name
Type
Reset
31:1
reserved
RO
0x0000.000
0
PRIMASK
R/W
0
RO
0
PRIMASK
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.
Priority Mask
Value Description
1
Prevents the activation of all exceptions with configurable
priority.
0
No effect.
90
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 19: Fault Mask Register (FAULTMASK)
The FAULTMASK register prevents activation of all exceptions except for the Non-Maskable Interrupt
(NMI). Exceptions should be disabled when they might impact the timing of critical tasks. This register
is only accessible in privileged mode. The MSR and MRS instructions are used to access the
FAULTMASK register, and the CPS instruction may be used to change the value of the FAULTMASK
register. See the Cortex™-M3/M4 Instruction Set Technical User's Manual for more information on
these instructions. For more information on exception priority levels, see “Exception
Types” on page 104.
Fault Mask Register (FAULTMASK)
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
Bit/Field
Name
Type
Reset
31:1
reserved
RO
0x0000.000
0
FAULTMASK
R/W
0
RO
0
FAULTMASK
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.
Fault Mask
Value Description
1
Prevents the activation of all exceptions except for NMI.
0
No effect.
The processor clears the FAULTMASK bit on exit from any exception
handler except the NMI handler.
July 03, 2014
91
Texas Instruments-Production Data
The Cortex-M3 Processor
Register 20: Base Priority Mask Register (BASEPRI)
The BASEPRI register defines the minimum priority for exception processing. When BASEPRI is
set to a nonzero value, it prevents the activation of all exceptions with the same or lower priority
level as the BASEPRI value. Exceptions should be disabled when they might impact the timing of
critical tasks. This register is only accessible in privileged mode. For more information on exception
priority levels, see “Exception Types” on page 104.
Base Priority Mask Register (BASEPRI)
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
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
BASEPRI
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:5
BASEPRI
R/W
0x0
R/W
0
reserved
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Base Priority
Any exception that has a programmable priority level with the same or
lower priority as the value of this field is masked. The PRIMASK register
can be used to mask all exceptions with programmable priority levels.
Higher priority exceptions have lower priority levels.
Value Description
4:0
reserved
RO
0x0
0x0
All exceptions are unmasked.
0x1
All exceptions with priority level 1-7 are masked.
0x2
All exceptions with priority level 2-7 are masked.
0x3
All exceptions with priority level 3-7 are masked.
0x4
All exceptions with priority level 4-7 are masked.
0x5
All exceptions with priority level 5-7 are masked.
0x6
All exceptions with priority level 6-7 are masked.
0x7
All exceptions with priority level 7 are masked.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
92
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 21: Control Register (CONTROL)
The CONTROL register controls the stack used and the privilege level for software execution when
the processor is in Thread mode. This register is only accessible in privileged mode.
Handler mode always uses MSP, so the processor ignores explicit writes to the ASP bit of the
CONTROL register when in Handler mode. The exception entry and return mechanisms automatically
update the CONTROL register based on the EXC_RETURN value (see Table 2-10 on page 111).
In an OS environment, threads running in Thread mode should use the process stack and the kernel
and exception handlers should use the main stack. By default, Thread mode uses MSP. To switch
the stack pointer used in Thread mode to PSP, either use the MSR instruction to set the ASP bit, as
detailed in the Cortex™-M3/M4 Instruction Set Technical User's Manual, or perform an exception
return to Thread mode with the appropriate EXC_RETURN value, as shown in Table 2-10 on page 111.
Note:
When changing the stack pointer, software must use an ISB instruction immediately after
the MSR instruction, ensuring that instructions after the ISB execute use the new stack
pointer. See the Cortex™-M3/M4 Instruction Set Technical User's Manual.
Control Register (CONTROL)
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
ASP
TMPL
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
31:2
reserved
RO
0x0000.000
1
ASP
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.
Active Stack Pointer
Value Description
1
PSP is the current stack pointer.
0
MSP is the current stack pointer
In Handler mode, this bit reads as zero and ignores writes. The
Cortex-M3 updates this bit automatically on exception return.
0
TMPL
R/W
0
Thread Mode Privilege Level
Value Description
1
Unprivileged software can be executed in Thread mode.
0
Only privileged software can be executed in Thread mode.
July 03, 2014
93
Texas Instruments-Production Data
The Cortex-M3 Processor
2.3.5
Exceptions and Interrupts
The Cortex-M3 processor supports interrupts and system exceptions. The processor and the Nested
Vectored Interrupt Controller (NVIC) prioritize and handle all exceptions. An exception changes the
normal flow of software control. The processor uses Handler mode to handle all exceptions except
for reset. See “Exception Entry and Return” on page 109 for more information.
The NVIC registers control interrupt handling. See “Nested Vectored Interrupt Controller
(NVIC)” on page 119 for more information.
2.3.6
Data Types
The Cortex-M3 supports 32-bit words, 16-bit halfwords, and 8-bit bytes. The processor also supports
64-bit data transfer instructions. All instruction and data memory accesses are little endian. See
“Memory Regions, Types and Attributes” on page 96 for more information.
2.4
Memory Model
This section describes the processor memory map, the behavior of memory accesses, and the
bit-banding features. The processor has a fixed memory map that provides up to 4 GB of addressable
memory.
The memory map for the LM3S5791 controller is provided in Table 2-4 on page 94. In this manual,
register addresses are given as a hexadecimal increment, relative to the module’s base address
as shown in the memory map.
The regions for SRAM and peripherals include bit-band regions. Bit-banding provides atomic
operations to bit data (see “Bit-Banding” on page 99).
The processor reserves regions of the Private peripheral bus (PPB) address range for core peripheral
registers (see “Cortex-M3 Peripherals” on page 118).
Note:
Within the memory map, all reserved space returns a bus fault when read or written.
Table 2-4. Memory Map
Start
End
Description
For details,
see page ...
0x0000.0000
0x0001.FFFF
On-chip Flash
310
0x0002.0000
0x00FF.FFFF
Reserved
-
0x0100.0000
0x1FFF.FFFF
Reserved for ROM
302
0x2000.0000
0x2000.FFFF
Bit-banded on-chip SRAM
302
0x2001.0000
0x21FF.FFFF
Reserved
-
0x2200.0000
0x221F.FFFF
Bit-band alias of bit-banded on-chip SRAM starting at
0x2000.0000
302
0x2220.0000
0x3FFF.FFFF
Reserved
-
0x4000.0000
0x4000.0FFF
Watchdog timer 0
576
0x4000.1000
0x4000.1FFF
Watchdog timer 1
576
0x4000.2000
0x4000.3FFF
Reserved
-
0x4000.4000
0x4000.4FFF
GPIO Port A
410
0x4000.5000
0x4000.5FFF
GPIO Port B
410
0x4000.6000
0x4000.6FFF
GPIO Port C
410
Memory
FiRM Peripherals
94
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 2-4. Memory Map (continued)
Start
End
Description
For details,
see page ...
0x4000.7000
0x4000.7FFF
GPIO Port D
410
0x4000.8000
0x4000.8FFF
SSI0
756
0x4000.9000
0x4000.9FFF
SSI1
756
0x4000.A000
0x4000.BFFF
Reserved
-
0x4000.C000
0x4000.CFFF
UART0
692
0x4000.D000
0x4000.DFFF
UART1
692
0x4000.E000
0x4000.EFFF
UART2
692
0x4000.F000
0x4001.FFFF
Reserved
-
0x4002.0FFF
I2C 0
800
0x4002.1000
0x4002.1FFF
I2C
800
0x4002.2000
0x4002.3FFF
Reserved
-
0x4002.4000
0x4002.4FFF
GPIO Port E
410
0x4002.5000
0x4002.5FFF
GPIO Port F
410
0x4002.6000
0x4002.6FFF
GPIO Port G
410
0x4002.7000
0x4002.7FFF
GPIO Port H
410
0x4002.8000
0x4002.8FFF
PWM
1078
0x4002.9000
0x4002.BFFF
Reserved
-
0x4002.C000
0x4002.CFFF
QEI0
1147
0x4002.D000
0x4002.DFFF
QEI1
1147
0x4002.E000
0x4002.FFFF
Reserved
-
0x4003.0000
0x4003.0FFF
Timer 0
542
0x4003.1000
0x4003.1FFF
Timer 1
542
0x4003.2000
0x4003.2FFF
Timer 2
542
0x4003.3000
0x4003.3FFF
Timer 3
542
0x4003.4000
0x4003.7FFF
Reserved
-
0x4003.8000
0x4003.8FFF
ADC0
620
0x4003.9000
0x4003.9FFF
ADC1
620
0x4003.A000
0x4003.BFFF
Reserved
-
0x4003.C000
0x4003.CFFF
Analog Comparators
1049
0x4003.D000
0x4003.DFFF
GPIO Port J
410
0x4003.E000
0x4003.FFFF
Reserved
-
0x4004.0000
0x4004.0FFF
CAN0 Controller
879
0x4004.1000
0x4004.1FFF
CAN1 Controller
879
0x4004.2000
0x4004.FFFF
Reserved
-
0x4005.0000
0x4005.0FFF
USB
937
0x4005.1000
0x4005.3FFF
Reserved
-
0x4005.4000
0x4005.4FFF
I2S0
834
0x4005.5000
0x4005.7FFF
Reserved
-
0x4005.8000
0x4005.8FFF
GPIO Port A (AHB aperture)
410
0x4005.9000
0x4005.9FFF
GPIO Port B (AHB aperture)
410
Peripherals
0x4002.0000
1
July 03, 2014
95
Texas Instruments-Production Data
The Cortex-M3 Processor
Table 2-4. Memory Map (continued)
Start
End
Description
For details,
see page ...
0x4005.A000
0x4005.AFFF
GPIO Port C (AHB aperture)
410
0x4005.B000
0x4005.BFFF
GPIO Port D (AHB aperture)
410
0x4005.C000
0x4005.CFFF
GPIO Port E (AHB aperture)
410
0x4005.D000
0x4005.DFFF
GPIO Port F (AHB aperture)
410
0x4005.E000
0x4005.EFFF
GPIO Port G (AHB aperture)
410
0x4005.F000
0x4005.FFFF
GPIO Port H (AHB aperture)
410
0x4006.0000
0x4006.0FFF
GPIO Port J (AHB aperture)
410
0x4006.1000
0x400C.FFFF
Reserved
-
0x400D.0000
0x400D.0FFF
EPI 0
484
0x400D.1000
0x400F.CFFF
Reserved
-
0x400F.D000
0x400F.DFFF
Flash memory control
310
0x400F.E000
0x400F.EFFF
System control
213
0x400F.F000
0x400F.FFFF
µDMA
360
0x4010.0000
0x41FF.FFFF
Reserved
-
0x4200.0000
0x43FF.FFFF
Bit-banded alias of 0x4000.0000 through 0x400F.FFFF
-
0x4400.0000
0x5FFF.FFFF
Reserved
-
0x6000.0000
0xDFFF.FFFF
EPI0 mapped peripheral and RAM
-
0xE000.0000
0xE000.0FFF
Instrumentation Trace Macrocell (ITM)
77
0xE000.1000
0xE000.1FFF
Data Watchpoint and Trace (DWT)
77
0xE000.2000
0xE000.2FFF
Flash Patch and Breakpoint (FPB)
77
0xE000.3000
0xE000.DFFF
Reserved
-
0xE000.E000
0xE000.EFFF
Cortex-M3 Peripherals (SysTick, NVIC, MPU and SCB)
126
0xE000.F000
0xE003.FFFF
Reserved
-
0xE004.0000
0xE004.0FFF
Trace Port Interface Unit (TPIU)
78
0xE004.1000
0xFFFF.FFFF
Reserved
-
Private Peripheral Bus
2.4.1
Memory Regions, Types and Attributes
The memory map and the programming of the MPU split the memory map into regions. Each region
has a defined memory type, and some regions have additional memory attributes. The memory
type and attributes determine the behavior of accesses to the region.
The memory types are:
■ Normal: The processor can re-order transactions for efficiency and perform speculative reads.
■ Device: The processor preserves transaction order relative to other transactions to Device or
Strongly Ordered memory.
■ Strongly Ordered: The processor preserves transaction order relative to all other transactions.
The different ordering requirements for Device and Strongly Ordered memory mean that the memory
system can buffer a write to Device memory but must not buffer a write to Strongly Ordered memory.
96
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
An additional memory attribute is Execute Never (XN), which means the processor prevents
instruction accesses. A fault exception is generated only on execution of an instruction executed
from an XN region.
2.4.2
Memory System Ordering of Memory Accesses
For most memory accesses caused by explicit memory access instructions, the memory system
does not guarantee that the order in which the accesses complete matches the program order of
the instructions, providing the order does not affect the behavior of the instruction sequence. Normally,
if correct program execution depends on two memory accesses completing in program order,
software must insert a memory barrier instruction between the memory access instructions (see
“Software Ordering of Memory Accesses” on page 98).
However, the memory system does guarantee ordering of accesses to Device and Strongly Ordered
memory. For two memory access instructions A1 and A2, if both A1 and A2 are accesses to either
Device or Strongly Ordered memory, and if A1 occurs before A2 in program order, A1 is always
observed before A2.
2.4.3
Behavior of Memory Accesses
Table 2-5 on page 97 shows the behavior of accesses to each region in the memory map. See
“Memory Regions, Types and Attributes” on page 96 for more information on memory types and
the XN attribute. Stellaris devices may have reserved memory areas within the address ranges
shown below (refer to Table 2-4 on page 94 for more information).
Table 2-5. Memory Access Behavior
Address Range
Memory Region
Memory Type
Execute
Never
(XN)
Description
0x0000.0000 - 0x1FFF.FFFF Code
Normal
-
This executable region is for program code.
Data can also be stored here.
0x2000.0000 - 0x3FFF.FFFF SRAM
Normal
-
This executable region is for data. Code
can also be stored here. This region
includes bit band and bit band alias areas
(see Table 2-6 on page 99).
0x4000.0000 - 0x5FFF.FFFF Peripheral
Device
XN
This region includes bit band and bit band
alias areas (see Table 2-7 on page 99).
0x6000.0000 - 0x9FFF.FFFF External RAM
Normal
-
This executable region is for data.
0xA000.0000 - 0xDFFF.FFFF External device
Device
XN
This region is for external device memory.
0xE000.0000- 0xE00F.FFFF Private peripheral
bus
Strongly
Ordered
XN
This region includes the NVIC, system
timer, and system control block.
0xE010.0000- 0xFFFF.FFFF Reserved
-
-
-
The Code, SRAM, and external RAM regions can hold programs. However, it is recommended that
programs always use the Code region because the Cortex-M3 has separate buses that can perform
instruction fetches and data accesses simultaneously.
The MPU can override the default memory access behavior described in this section. For more
information, see “Memory Protection Unit (MPU)” on page 121.
The Cortex-M3 prefetches instructions ahead of execution and speculatively prefetches from branch
target addresses.
July 03, 2014
97
Texas Instruments-Production Data
The Cortex-M3 Processor
2.4.4
Software Ordering of Memory Accesses
The order of instructions in the program flow does not always guarantee the order of the
corresponding memory transactions for the following reasons:
■ The processor can reorder some memory accesses to improve efficiency, providing this does
not affect the behavior of the instruction sequence.
■ The processor has multiple bus interfaces.
■ Memory or devices in the memory map have different wait states.
■ Some memory accesses are buffered or speculative.
“Memory System Ordering of Memory Accesses” on page 97 describes the cases where the memory
system guarantees the order of memory accesses. Otherwise, if the order of memory accesses is
critical, software must include memory barrier instructions to force that ordering. The Cortex-M3
has the following memory barrier instructions:
■ The Data Memory Barrier (DMB) instruction ensures that outstanding memory transactions
complete before subsequent memory transactions.
■ The Data Synchronization Barrier (DSB) instruction ensures that outstanding memory transactions
complete before subsequent instructions execute.
■ The Instruction Synchronization Barrier (ISB) instruction ensures that the effect of all completed
memory transactions is recognizable by subsequent instructions.
Memory barrier instructions can be used in the following situations:
■ MPU programming
– If the MPU settings are changed and the change must be effective on the very next instruction,
use a DSB instruction to ensure the effect of the MPU takes place immediately at the end of
context switching.
– Use an ISB instruction to ensure the new MPU setting takes effect immediately after
programming the MPU region or regions, if the MPU configuration code was accessed using
a branch or call. If the MPU configuration code is entered using exception mechanisms, then
an ISB instruction is not required.
■ Vector table
If the program changes an entry in the vector table and then enables the corresponding exception,
use a DMB instruction between the operations. The DMB instruction ensures that if the exception
is taken immediately after being enabled, the processor uses the new exception vector.
■ Self-modifying code
If a program contains self-modifying code, use an ISB instruction immediately after the code
modification in the program. The ISB instruction ensures subsequent instruction execution uses
the updated program.
■ Memory map switching
98
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
If the system contains a memory map switching mechanism, use a DSB instruction after switching
the memory map in the program. The DSB instruction ensures subsequent instruction execution
uses the updated memory map.
■ Dynamic exception priority change
When an exception priority has to change when the exception is pending or active, use DSB
instructions after the change. The change then takes effect on completion of the DSB instruction.
Memory accesses to Strongly Ordered memory, such as the System Control Block, do not require
the use of DMB instructions.
For more information on the memory barrier instructions, see the Cortex™-M3/M4 Instruction Set
Technical User's Manual.
2.4.5
Bit-Banding
A bit-band region maps each word in a bit-band alias region to a single bit in the bit-band region.
The bit-band regions occupy the lowest 1 MB of the SRAM and peripheral memory regions. Accesses
to the 32-MB SRAM alias region map to the 1-MB SRAM bit-band region, as shown in Table
2-6 on page 99. Accesses to the 32-MB peripheral alias region map to the 1-MB peripheral bit-band
region, as shown in Table 2-7 on page 99. For the specific address range of the bit-band regions,
see Table 2-4 on page 94.
Note:
A word access to the SRAM or the peripheral bit-band alias region maps to a single bit in
the SRAM or peripheral bit-band region.
A word access to a bit band address results in a word access to the underlying memory,
and similarly for halfword and byte accesses. This allows bit band accesses to match the
access requirements of the underlying peripheral.
Table 2-6. SRAM Memory Bit-Banding Regions
Address Range
Memory Region
Instruction and Data Accesses
Start
End
0x2000.0000
0x2000.FFFF
SRAM bit-band region Direct accesses to this memory range behave as SRAM
memory accesses, but this region is also bit addressable
through bit-band alias.
0x2200.0000
0x221F.FFFF
SRAM bit-band alias
Data accesses to this region are remapped to bit band
region. A write operation is performed as
read-modify-write. Instruction accesses are not remapped.
Table 2-7. Peripheral Memory Bit-Banding Regions
Address Range
Memory Region
Instruction and Data Accesses
0x400F.FFFF
Peripheral bit-band
region
Direct accesses to this memory range behave as
peripheral memory accesses, but this region is also bit
addressable through bit-band alias.
0x43FF.FFFF
Peripheral bit-band alias Data accesses to this region are remapped to bit band
region. A write operation is performed as
read-modify-write. Instruction accesses are not permitted.
Start
End
0x4000.0000
0x4200.0000
The following formula shows how the alias region maps onto the bit-band region:
bit_word_offset = (byte_offset x 32) + (bit_number x 4)
July 03, 2014
99
Texas Instruments-Production Data
The Cortex-M3 Processor
bit_word_addr = bit_band_base + bit_word_offset
where:
bit_word_offset
The position of the target bit in the bit-band memory region.
bit_word_addr
The address of the word in the alias memory region that maps to the targeted bit.
bit_band_base
The starting address of the alias region.
byte_offset
The number of the byte in the bit-band region that contains the targeted bit.
bit_number
The bit position, 0-7, of the targeted bit.
Figure 2-4 on page 101 shows examples of bit-band mapping between the SRAM bit-band alias
region and the SRAM bit-band region:
■ The alias word at 0x23FF.FFE0 maps to bit 0 of the bit-band byte at 0x200F.FFFF:
0x23FF.FFE0 = 0x2200.0000 + (0x000F.FFFF*32) + (0*4)
■ The alias word at 0x23FF.FFFC maps to bit 7 of the bit-band byte at 0x200F.FFFF:
0x23FF.FFFC = 0x2200.0000 + (0x000F.FFFF*32) + (7*4)
■ The alias word at 0x2200.0000 maps to bit 0 of the bit-band byte at 0x2000.0000:
0x2200.0000 = 0x2200.0000 + (0*32) + (0*4)
■ The alias word at 0x2200.001C maps to bit 7 of the bit-band byte at 0x2000.0000:
0x2200.001C = 0x2200.0000+ (0*32) + (7*4)
100
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 2-4. Bit-Band Mapping
32-MB Alias Region
0x23FF.FFFC
0x23FF.FFF8
0x23FF.FFF4
0x23FF.FFF0
0x23FF.FFEC
0x23FF.FFE8
0x23FF.FFE4
0x23FF.FFE0
0x2200.001C
0x2200.0018
0x2200.0014
0x2200.0010
0x2200.000C
0x2200.0008
0x2200.0004
0x2200.0000
7
3
1-MB SRAM Bit-Band Region
7
6
5
4
3
2
1
0
7
6
0x200F.FFFF
7
6
5
4
3
2
0x2000.0003
2.4.5.1
5
4
3
2
1
0
7
6
0x200F.FFFE
1
0
7
6
5
4
3
2
5
4
3
2
1
0
6
0x200F.FFFD
1
0
0x2000.0002
7
6
5
4
3
2
0x2000.0001
5
4
2
1
0
1
0
0x200F.FFFC
1
0
7
6
5
4
3
2
0x2000.0000
Directly Accessing an Alias Region
Writing to a word in the alias region updates a single bit in the bit-band region.
Bit 0 of the value written to a word in the alias region determines the value written to the targeted
bit in the bit-band region. Writing a value with bit 0 set writes a 1 to the bit-band bit, and writing a
value with bit 0 clear writes a 0 to the bit-band bit.
Bits 31:1 of the alias word have no effect on the bit-band bit. Writing 0x01 has the same effect as
writing 0xFF. Writing 0x00 has the same effect as writing 0x0E.
When reading a word in the alias region, 0x0000.0000 indicates that the targeted bit in the bit-band
region is clear and 0x0000.0001 indicates that the targeted bit in the bit-band region is set.
2.4.5.2
Directly Accessing a Bit-Band Region
“Behavior of Memory Accesses” on page 97 describes the behavior of direct byte, halfword, or word
accesses to the bit-band regions.
2.4.6
Data Storage
The processor views memory as a linear collection of bytes numbered in ascending order from zero.
For example, bytes 0-3 hold the first stored word, and bytes 4-7 hold the second stored word. Data
is stored in little-endian format, with the least-significant byte (lsbyte) of a word stored at the
lowest-numbered byte, and the most-significant byte (msbyte) stored at the highest-numbered byte.
Figure 2-5 on page 102 illustrates how data is stored.
July 03, 2014
101
Texas Instruments-Production Data
The Cortex-M3 Processor
Figure 2-5. Data Storage
Memory
7
Register
0
31
2.4.7
Address A
B0
A+1
B1
A+2
B2
A+3
B3
lsbyte
24 23
B3
16 15
B2
8 7
B1
0
B0
msbyte
Synchronization Primitives
The Cortex-M3 instruction set includes pairs of synchronization primitives which provide a
non-blocking mechanism that a thread or process can use to obtain exclusive access to a memory
location. Software can use these primitives to perform a guaranteed read-modify-write memory
update sequence or for a semaphore mechanism.
A pair of synchronization primitives consists of:
■ A Load-Exclusive instruction, which is used to read the value of a memory location and requests
exclusive access to that location.
■ A Store-Exclusive instruction, which is used to attempt to write to the same memory location and
returns a status bit to a register. If this status bit is clear, it indicates that the thread or process
gained exclusive access to the memory and the write succeeds; if this status bit is set, it indicates
that the thread or process did not gain exclusive access to the memory and no write was
performed.
The pairs of Load-Exclusive and Store-Exclusive instructions are:
■ The word instructions LDREX and STREX
■ The halfword instructions LDREXH and STREXH
■ The byte instructions LDREXB and STREXB
Software must use a Load-Exclusive instruction with the corresponding Store-Exclusive instruction.
To perform an exclusive read-modify-write of a memory location, software must:
1. Use a Load-Exclusive instruction to read the value of the location.
2. Modify the value, as required.
3. Use a Store-Exclusive instruction to attempt to write the new value back to the memory location.
4. Test the returned status bit.
If the status bit is clear, the read-modify-write completed successfully. If the status bit is set, no
write was performed, which indicates that the value returned at step 1 might be out of date. The
software must retry the entire read-modify-write sequence.
Software can use the synchronization primitives to implement a semaphore as follows:
102
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
1. Use a Load-Exclusive instruction to read from the semaphore address to check whether the
semaphore is free.
2. If the semaphore is free, use a Store-Exclusive to write the claim value to the semaphore
address.
3. If the returned status bit from step 2 indicates that the Store-Exclusive succeeded, then the
software has claimed the semaphore. However, if the Store-Exclusive failed, another process
might have claimed the semaphore after the software performed step 1.
The Cortex-M3 includes an exclusive access monitor that tags the fact that the processor has
executed a Load-Exclusive instruction. The processor removes its exclusive access tag if:
■ It executes a CLREX instruction.
■ It executes a Store-Exclusive instruction, regardless of whether the write succeeds.
■ An exception occurs, which means the processor can resolve semaphore conflicts between
different threads.
For more information about the synchronization primitive instructions, see the Cortex™-M3/M4
Instruction Set Technical User's Manual.
2.5
Exception Model
The ARM Cortex-M3 processor and the Nested Vectored Interrupt Controller (NVIC) prioritize and
handle all exceptions in Handler Mode. The processor state is automatically stored to the stack on
an exception and automatically restored from the stack at the end of the Interrupt Service Routine
(ISR). The vector is fetched in parallel to the state saving, enabling efficient interrupt entry. The
processor supports tail-chaining, which enables back-to-back interrupts to be performed without the
overhead of state saving and restoration.
Table 2-8 on page 105 lists all exception types. Software can set eight priority levels on seven of
these exceptions (system handlers) as well as on 52 interrupts (listed in Table 2-9 on page 106).
Priorities on the system handlers are set with the NVIC System Handler Priority n (SYSPRIn)
registers. Interrupts are enabled through the NVIC Interrupt Set Enable n (ENn) register and
prioritized with the NVIC Interrupt Priority n (PRIn) registers. Priorities can be grouped by splitting
priority levels into preemption priorities and subpriorities. All the interrupt registers are described in
“Nested Vectored Interrupt Controller (NVIC)” on page 119.
Internally, the highest user-programmable priority (0) is treated as fourth priority, after a Reset,
Non-Maskable Interrupt (NMI), and a Hard Fault, in that order. Note that 0 is the default priority for
all the programmable priorities.
Important: After a write to clear an interrupt source, it may take several processor cycles for the
NVIC to see the interrupt source de-assert. Thus if the interrupt clear is done as the
last action in an interrupt handler, it is possible for the interrupt handler to complete
while the NVIC sees the interrupt as still asserted, causing the interrupt handler to be
re-entered errantly. This situation can be avoided by either clearing the interrupt source
at the beginning of the interrupt handler or by performing a read or write after the write
to clear the interrupt source (and flush the write buffer).
See “Nested Vectored Interrupt Controller (NVIC)” on page 119 for more information on exceptions
and interrupts.
July 03, 2014
103
Texas Instruments-Production Data
The Cortex-M3 Processor
2.5.1
Exception States
Each exception is in one of the following states:
■ Inactive. The exception is not active and not pending.
■ Pending. The exception is waiting to be serviced by the processor. An interrupt request from a
peripheral or from software can change the state of the corresponding interrupt to pending.
■ Active. An exception that is being serviced by the processor but has not completed.
Note:
An exception handler can interrupt the execution of another exception handler. In this
case, both exceptions are in the active state.
■ Active and Pending. The exception is being serviced by the processor, and there is a pending
exception from the same source.
2.5.2
Exception Types
The exception types are:
■ Reset. Reset is invoked on power up or a warm reset. The exception model treats reset as a
special form of exception. When reset is asserted, the operation of the processor stops, potentially
at any point in an instruction. When reset is deasserted, execution restarts from the address
provided by the reset entry in the vector table. Execution restarts as privileged execution in
Thread mode.
■ NMI. A non-maskable Interrupt (NMI) can be signaled using the NMI signal or triggered by
software using the Interrupt Control and State (INTCTRL) register. This exception has the
highest priority other than reset. NMI is permanently enabled and has a fixed priority of -2. NMIs
cannot be masked or prevented from activation by any other exception or preempted by any
exception other than reset.
■ Hard Fault. A hard fault is an exception that occurs because of an error during exception
processing, or because an exception cannot be managed by any other exception mechanism.
Hard faults have a fixed priority of -1, meaning they have higher priority than any exception with
configurable priority.
■ Memory Management Fault. A memory management fault is an exception that occurs because
of a memory protection related fault, including access violation and no match. The MPU or the
fixed memory protection constraints determine this fault, for both instruction and data memory
transactions. This fault is used to abort instruction accesses to Execute Never (XN) memory
regions, even if the MPU is disabled.
■ Bus Fault. A bus fault is an exception that occurs because of a memory-related fault for an
instruction or data memory transaction such as a prefetch fault or a memory access fault. This
fault can be enabled or disabled.
■ Usage Fault. A usage fault is an exception that occurs because of a fault related to instruction
execution, such as:
– An undefined instruction
– An illegal unaligned access
– Invalid state on instruction execution
104
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
– An error on exception return
An unaligned address on a word or halfword memory access or division by zero can cause a
usage fault when the core is properly configured.
■ SVCall. A supervisor call (SVC) is an exception that is triggered by the SVC instruction. In an
OS environment, applications can use SVC instructions to access OS kernel functions and device
drivers.
■ Debug Monitor. This exception is caused by the debug monitor (when not halting). This exception
is only active when enabled. This exception does not activate if it is a lower priority than the
current activation.
■ PendSV. PendSV is a pendable, interrupt-driven request for system-level service. In an OS
environment, use PendSV for context switching when no other exception is active. PendSV is
triggered using the Interrupt Control and State (INTCTRL) register.
■ SysTick. A SysTick exception is an exception that the system timer generates when it reaches
zero when it is enabled to generate an interrupt. Software can also generate a SysTick exception
using the Interrupt Control and State (INTCTRL) register. In an OS environment, the processor
can use this exception as system tick.
■ Interrupt (IRQ). An interrupt, or IRQ, is an exception signaled by a peripheral or generated by
a software request and fed through the NVIC (prioritized). All interrupts are asynchronous to
instruction execution. In the system, peripherals use interrupts to communicate with the processor.
Table 2-9 on page 106 lists the interrupts on the LM3S5791 controller.
For an asynchronous exception, other than reset, the processor can execute another instruction
between when the exception is triggered and when the processor enters the exception handler.
Privileged software can disable the exceptions that Table 2-8 on page 105 shows as having
configurable priority (see the SYSHNDCTRL register on page 162 and the DIS0 register on page 135).
For more information about hard faults, memory management faults, bus faults, and usage faults,
see “Fault Handling” on page 111.
Table 2-8. Exception Types
Exception Type
a
Vector
Number
Priority
Vector Address or
b
Offset
-
0
-
0x0000.0000
Stack top is loaded from the first
entry of the vector table on reset.
Reset
1
-3 (highest)
0x0000.0004
Asynchronous
Non-Maskable Interrupt
(NMI)
2
-2
0x0000.0008
Asynchronous
Hard Fault
3
-1
0x0000.000C
-
c
0x0000.0010
Synchronous
c
0x0000.0014
Synchronous when precise and
asynchronous when imprecise
c
Synchronous
Memory Management
4
programmable
Bus Fault
5
programmable
Usage Fault
6
programmable
0x0000.0018
7-10
-
-
-
Activation
c
c
Reserved
SVCall
11
programmable
0x0000.002C
Synchronous
Debug Monitor
12
programmable
0x0000.0030
Synchronous
-
13
-
-
July 03, 2014
Reserved
105
Texas Instruments-Production Data
The Cortex-M3 Processor
Table 2-8. Exception Types (continued)
Exception Type
PendSV
SysTick
a
Vector
Number
Priority
14
programmable
15
Interrupts
Vector Address or
b
Offset
c
0x0000.0038
Asynchronous
c
0x0000.003C
Asynchronous
programmable
16 and above
Activation
d
programmable
0x0000.0040 and above Asynchronous
a. 0 is the default priority for all the programmable priorities.
b. See “Vector Table” on page 107.
c. See SYSPRI1 on page 159.
d. See PRIn registers on page 143.
Table 2-9. Interrupts
Vector Number
Interrupt Number (Bit
in Interrupt Registers)
Vector Address or
Offset
Description
0-15
-
0x0000.0000 0x0000.003C
16
0
0x0000.0040
GPIO Port A
17
1
0x0000.0044
GPIO Port B
18
2
0x0000.0048
GPIO Port C
19
3
0x0000.004C
GPIO Port D
20
4
0x0000.0050
GPIO Port E
21
5
0x0000.0054
UART0
22
6
0x0000.0058
UART1
23
7
0x0000.005C
SSI0
24
8
0x0000.0060
I2C0
25
9
0x0000.0064
PWM Fault
26
10
0x0000.0068
PWM Generator 0
27
11
0x0000.006C
PWM Generator 1
28
12
0x0000.0070
PWM Generator 2
29
13
0x0000.0074
QEI0
30
14
0x0000.0078
ADC0 Sequence 0
31
15
0x0000.007C
ADC0 Sequence 1
32
16
0x0000.0080
ADC0 Sequence 2
33
17
0x0000.0084
ADC0 Sequence 3
34
18
0x0000.0088
Watchdog Timers 0 and 1
35
19
0x0000.008C
Timer 0A
36
20
0x0000.0090
Timer 0B
37
21
0x0000.0094
Timer 1A
38
22
0x0000.0098
Timer 1B
39
23
0x0000.009C
Timer 2A
40
24
0x0000.00A0
Timer 2B
41
25
0x0000.00A4
Analog Comparator 0
42
26
0x0000.00A8
Analog Comparator 1
43
27
0x0000.00AC
Analog Comparator 2
44
28
0x0000.00B0
System Control
Processor exceptions
106
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 2-9. Interrupts (continued)
2.5.3
Vector Number
Interrupt Number (Bit
in Interrupt Registers)
Vector Address or
Offset
Description
45
29
0x0000.00B4
Flash Memory Control
46
30
0x0000.00B8
GPIO Port F
47
31
0x0000.00BC
GPIO Port G
48
32
0x0000.00C0
GPIO Port H
49
33
0x0000.00C4
UART2
50
34
0x0000.00C8
SSI1
51
35
0x0000.00CC
Timer 3A
52
36
0x0000.00D0
Timer 3B
53
37
0x0000.00D4
I2C1
54
38
0x0000.00D8
QEI1
55
39
0x0000.00DC
CAN0
56
40
0x0000.00E0
CAN1
57-59
41-43
-
60
44
0x0000.00F0
USB
61
45
0x0000.00F4
PWM Generator 3
Reserved
62
46
0x0000.00F8
µDMA Software
63
47
0x0000.00FC
µDMA Error
64
48
0x0000.0100
ADC1 Sequence 0
65
49
0x0000.0104
ADC1 Sequence 1
66
50
0x0000.0108
ADC1 Sequence 2
67
51
0x0000.010C
ADC1 Sequence 3
68
52
0x0000.0110
I2S0
69
53
0x0000.0114
EPI
70
54
0x0000.0118
GPIO Port J
Exception Handlers
The processor handles exceptions using:
■ Interrupt Service Routines (ISRs). Interrupts (IRQx) are the exceptions handled by ISRs.
■ Fault Handlers. Hard fault, memory management fault, usage fault, and bus fault are fault
exceptions handled by the fault handlers.
■ System Handlers. NMI, PendSV, SVCall, SysTick, and the fault exceptions are all system
exceptions that are handled by system handlers.
2.5.4
Vector Table
The vector table contains the reset value of the stack pointer and the start addresses, also called
exception vectors, for all exception handlers. The vector table is constructed using the vector address
or offset shown in Table 2-8 on page 105. Figure 2-6 on page 108 shows the order of the exception
vectors in the vector table. The least-significant bit of each vector must be 1, indicating that the
exception handler is Thumb code
July 03, 2014
107
Texas Instruments-Production Data
The Cortex-M3 Processor
Figure 2-6. Vector Table
Exception number IRQ number
70
54
.
.
.
18
2
17
1
16
0
15
-1
14
-2
13
Offset
0x0118
.
.
.
0x004C
0x0048
0x0044
0x0040
0x003C
0x0038
12
11
Vector
IRQ54
.
.
.
IRQ2
IRQ1
IRQ0
Systick
PendSV
Reserved
Reserved for Debug
-5
10
0x002C
9
SVCall
Reserved
8
7
6
-10
5
-11
4
-12
3
-13
2
-14
1
0x0018
0x0014
0x0010
0x000C
0x0008
0x0004
0x0000
Usage fault
Bus fault
Memory management fault
Hard fault
NMI
Reset
Initial SP value
On system reset, the vector table is fixed at address 0x0000.0000. Privileged software can write to
the Vector Table Offset (VTABLE) register to relocate the vector table start address to a different
memory location, in the range 0x0000.0200 to 0x3FFF.FE00 (see “Vector Table” on page 107). Note
that when configuring the VTABLE register, the offset must be aligned on a 512-byte boundary.
2.5.5
Exception Priorities
As Table 2-8 on page 105 shows, all exceptions have an associated priority, with a lower priority
value indicating a higher priority and configurable priorities for all exceptions except Reset, Hard
fault, and NMI. If software does not configure any priorities, then all exceptions with a configurable
priority have a priority of 0. For information about configuring exception priorities, see page 159 and
page 143.
Note:
Configurable priority values for the Stellaris implementation are in the range 0-7. This means
that the Reset, Hard fault, and NMI exceptions, with fixed negative priority values, always
have higher priority than any other exception.
For example, assigning a higher priority value to IRQ[0] and a lower priority value to IRQ[1] means
that IRQ[1] has higher priority than IRQ[0]. If both IRQ[1] and IRQ[0] are asserted, IRQ[1] is processed
before IRQ[0].
108
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
If multiple pending exceptions have the same priority, the pending exception with the lowest exception
number takes precedence. For example, if both IRQ[0] and IRQ[1] are pending and have the same
priority, then IRQ[0] is processed before IRQ[1].
When the processor is executing an exception handler, the exception handler is preempted if a
higher priority exception occurs. If an exception occurs with the same priority as the exception being
handled, the handler is not preempted, irrespective of the exception number. However, the status
of the new interrupt changes to pending.
2.5.6
Interrupt Priority Grouping
To increase priority control in systems with interrupts, the NVIC supports priority grouping. This
grouping divides each interrupt priority register entry into two fields:
■ An upper field that defines the group priority
■ A lower field that defines a subpriority within the group
Only the group priority determines preemption of interrupt exceptions. When the processor is
executing an interrupt exception handler, another interrupt with the same group priority as the
interrupt being handled does not preempt the handler.
If multiple pending interrupts have the same group priority, the subpriority field determines the order
in which they are processed. If multiple pending interrupts have the same group priority and
subpriority, the interrupt with the lowest IRQ number is processed first.
For information about splitting the interrupt priority fields into group priority and subpriority, see
page 153.
2.5.7
Exception Entry and Return
Descriptions of exception handling use the following terms:
■ Preemption. When the processor is executing an exception handler, an exception can preempt
the exception handler if its priority is higher than the priority of the exception being handled. See
“Interrupt Priority Grouping” on page 109 for more information about preemption by an interrupt.
When one exception preempts another, the exceptions are called nested exceptions. See
“Exception Entry” on page 110 more information.
■ Return. Return occurs when the exception handler is completed, and there is no pending
exception with sufficient priority to be serviced and the completed exception handler was not
handling a late-arriving exception. The processor pops the stack and restores the processor
state to the state it had before the interrupt occurred. See “Exception Return” on page 110 for
more information.
■ Tail-Chaining. This mechanism speeds up exception servicing. On completion of an exception
handler, if there is a pending exception that meets the requirements for exception entry, the
stack pop is skipped and control transfers to the new exception handler.
■ Late-Arriving. This mechanism speeds up preemption. If a higher priority exception occurs
during state saving for a previous exception, the processor switches to handle the higher priority
exception and initiates the vector fetch for that exception. State saving is not affected by late
arrival because the state saved is the same for both exceptions. Therefore, the state saving
continues uninterrupted. The processor can accept a late arriving exception until the first instruction
of the exception handler of the original exception enters the execute stage of the processor. On
July 03, 2014
109
Texas Instruments-Production Data
The Cortex-M3 Processor
return from the exception handler of the late-arriving exception, the normal tail-chaining rules
apply.
2.5.7.1
Exception Entry
Exception entry occurs when there is a pending exception with sufficient priority and either the
processor is in Thread mode or the new exception is of higher priority than the exception being
handled, in which case the new exception preempts the original exception.
When one exception preempts another, the exceptions are nested.
Sufficient priority means the exception has more priority than any limits set by the mask registers
(see PRIMASK on page 90, FAULTMASK on page 91, and BASEPRI on page 92). An exception
with less priority than this is pending but is not handled by the processor.
When the processor takes an exception, unless the exception is a tail-chained or a late-arriving
exception, the processor pushes information onto the current stack. This operation is referred to as
stacking and the structure of eight data words is referred to as stack frame.
Figure 2-7. Exception Stack Frame
...
{aligner}
xPSR
PC
LR
R12
R3
R2
R1
R0
Pre-IRQ top of stack
IRQ top of stack
Immediately after stacking, the stack pointer indicates the lowest address in the stack frame.
The stack frame includes the return address, which is the address of the next instruction in the
interrupted program. This value is restored to the PC at exception return so that the interrupted
program resumes.
In parallel to the stacking operation, the processor performs a vector fetch that reads the exception
handler start address from the vector table. When stacking is complete, the processor starts executing
the exception handler. At the same time, the processor writes an EXC_RETURN value to the LR,
indicating which stack pointer corresponds to the stack frame and what operation mode the processor
was in before the entry occurred.
If no higher-priority exception occurs during exception entry, the processor starts executing the
exception handler and automatically changes the status of the corresponding pending interrupt to
active.
If another higher-priority exception occurs during exception entry, known as late arrival, the processor
starts executing the exception handler for this exception and does not change the pending status
of the earlier exception.
2.5.7.2
Exception Return
Exception return occurs when the processor is in Handler mode and executes one of the following
instructions to load the EXC_RETURN value into the PC:
■ An LDM or POP instruction that loads the PC
110
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ A BX instruction using any register
■ An LDR instruction with the PC as the destination
EXC_RETURN is the value loaded into the LR on exception entry. The exception mechanism relies
on this value to detect when the processor has completed an exception handler. The lowest four
bits of this value provide information on the return stack and processor mode. Table 2-10 on page 111
shows the EXC_RETURN values with a description of the exception return behavior.
EXC_RETURN bits 31:4 are all set. When this value is loaded into the PC, it indicates to the processor
that the exception is complete, and the processor initiates the appropriate exception return sequence.
Table 2-10. Exception Return Behavior
EXC_RETURN[31:0]
Description
0xFFFF.FFF0
Reserved
0xFFFF.FFF1
Return to Handler mode.
Exception return uses state from MSP.
Execution uses MSP after return.
0xFFFF.FFF2 - 0xFFFF.FFF8
Reserved
0xFFFF.FFF9
Return to Thread mode.
Exception return uses state from MSP.
Execution uses MSP after return.
0xFFFF.FFFA - 0xFFFF.FFFC
Reserved
0xFFFF.FFFD
Return to Thread mode.
Exception return uses state from PSP.
Execution uses PSP after return.
0xFFFF.FFFE - 0xFFFF.FFFF
2.6
Reserved
Fault Handling
Faults are a subset of the exceptions (see “Exception Model” on page 103). The following conditions
generate a fault:
■ A bus error on an instruction fetch or vector table load or a data access.
■ An internally detected error such as an undefined instruction or an attempt to change state with
a BX instruction.
■ Attempting to execute an instruction from a memory region marked as Non-Executable (XN).
■ An MPU fault because of a privilege violation or an attempt to access an unmanaged region.
2.6.1
Fault Types
Table 2-11 on page 111 shows the types of fault, the handler used for the fault, the corresponding
fault status register, and the register bit that indicates the fault has occurred. See page 166 for more
information about the fault status registers.
Table 2-11. Faults
Fault
Handler
Fault Status Register
Bit Name
Bus error on a vector read
Hard fault
Hard Fault Status (HFAULTSTAT)
VECT
July 03, 2014
111
Texas Instruments-Production Data
The Cortex-M3 Processor
Table 2-11. Faults (continued)
Fault
Handler
Fault Status Register
Bit Name
Fault escalated to a hard fault
Hard fault
Hard Fault Status (HFAULTSTAT)
FORCED
MPU or default memory mismatch on Memory management
instruction access
fault
Memory Management Fault Status
(MFAULTSTAT)
IERR
MPU or default memory mismatch on Memory management
data access
fault
Memory Management Fault Status
(MFAULTSTAT)
DERR
MPU or default memory mismatch on Memory management
exception stacking
fault
Memory Management Fault Status
(MFAULTSTAT)
MSTKE
MPU or default memory mismatch on Memory management
exception unstacking
fault
Memory Management Fault Status
(MFAULTSTAT)
MUSTKE
Bus error during exception stacking
a
Bus fault
Bus Fault Status (BFAULTSTAT)
BSTKE
Bus error during exception unstacking Bus fault
Bus Fault Status (BFAULTSTAT)
BUSTKE
Bus error during instruction prefetch
Bus fault
Bus Fault Status (BFAULTSTAT)
IBUS
Precise data bus error
Bus fault
Bus Fault Status (BFAULTSTAT)
PRECISE
Imprecise data bus error
Bus fault
Bus Fault Status (BFAULTSTAT)
IMPRE
Attempt to access a coprocessor
Usage fault
Usage Fault Status (UFAULTSTAT)
NOCP
Undefined instruction
Usage fault
Usage Fault Status (UFAULTSTAT)
UNDEF
Attempt to enter an invalid instruction Usage fault
b
set state
Usage Fault Status (UFAULTSTAT)
INVSTAT
Invalid EXC_RETURN value
Usage fault
Usage Fault Status (UFAULTSTAT)
INVPC
Illegal unaligned load or store
Usage fault
Usage Fault Status (UFAULTSTAT)
UNALIGN
Divide by 0
Usage fault
Usage Fault Status (UFAULTSTAT)
DIV0
a. Occurs on an access to an XN region even if the MPU is disabled.
b. Attempting to use an instruction set other than the Thumb instruction set, or returning to a non load-store-multiple instruction
with ICI continuation.
2.6.2
Fault Escalation and Hard Faults
All fault exceptions except for hard fault have configurable exception priority (see SYSPRI1 on
page 159). Software can disable execution of the handlers for these faults (see SYSHNDCTRL on
page 162).
Usually, the exception priority, together with the values of the exception mask registers, determines
whether the processor enters the fault handler, and whether a fault handler can preempt another
fault handler as described in “Exception Model” on page 103.
In some situations, a fault with configurable priority is treated as a hard fault. This process is called
priority escalation, and the fault is described as escalated to hard fault. Escalation to hard fault
occurs when:
■ A fault handler causes the same kind of fault as the one it is servicing. This escalation to hard
fault occurs because a fault handler cannot preempt itself because it must have the same priority
as the current priority level.
■ A fault handler causes a fault with the same or lower priority as the fault it is servicing. This
situation happens because the handler for the new fault cannot preempt the currently executing
fault handler.
■ An exception handler causes a fault for which the priority is the same as or lower than the currently
executing exception.
112
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ A fault occurs and the handler for that fault is not enabled.
If a bus fault occurs during a stack push when entering a bus fault handler, the bus fault does not
escalate to a hard fault. Thus if a corrupted stack causes a fault, the fault handler executes even
though the stack push for the handler failed. The fault handler operates but the stack contents are
corrupted.
Note:
2.6.3
Only Reset and NMI can preempt the fixed priority hard fault. A hard fault can preempt any
exception other than Reset, NMI, or another hard fault.
Fault Status Registers and Fault Address Registers
The fault status registers indicate the cause of a fault. For bus faults and memory management
faults, the fault address register indicates the address accessed by the operation that caused the
fault, as shown in Table 2-12 on page 113.
Table 2-12. Fault Status and Fault Address Registers
2.6.4
Handler
Status Register Name
Address Register Name
Register Description
Hard fault
Hard Fault Status (HFAULTSTAT)
-
page 172
Memory management Memory Management Fault Status
fault
(MFAULTSTAT)
Memory Management Fault
Address (MMADDR)
page 166
Bus fault
Bus Fault Status (BFAULTSTAT)
Bus Fault Address
(FAULTADDR)
page 166
Usage fault
Usage Fault Status (UFAULTSTAT)
-
page 166
page 173
page 174
Lockup
The processor enters a lockup state if a hard fault occurs when executing the NMI or hard fault
handlers. When the processor is in the lockup state, it does not execute any instructions. The
processor remains in lockup state until it is reset, an NMI occurs, or it is halted by a debugger.
Note:
2.7
If the lockup state occurs from the NMI handler, a subsequent NMI does not cause the
processor to leave the lockup state.
Power Management
The Cortex-M3 processor sleep modes reduce power consumption:
■ Sleep mode stops the processor clock.
■ Deep-sleep mode stops the system clock and switches off the PLL and Flash memory.
The SLEEPDEEP bit of the System Control (SYSCTRL) register selects which sleep mode is used
(see page 155). For more information about the behavior of the sleep modes, see “System
Control” on page 209.
This section describes the mechanisms for entering sleep mode and the conditions for waking up
from sleep mode, both of which apply to Sleep mode and Deep-sleep mode.
2.7.1
Entering Sleep Modes
This section describes the mechanisms software can use to put the processor into one of the sleep
modes.
July 03, 2014
113
Texas Instruments-Production Data
The Cortex-M3 Processor
The system can generate spurious wake-up events, for example a debug operation wakes up the
processor. Therefore, software must be able to put the processor back into sleep mode after such
an event. A program might have an idle loop to put the processor back to sleep mode.
2.7.1.1
Wait for Interrupt
The wait for interrupt instruction, WFI, causes immediate entry to sleep mode unless the wake-up
condition is true (see “Wake Up from WFI or Sleep-on-Exit” on page 114). When the processor
executes a WFI instruction, it stops executing instructions and enters sleep mode. See the
Cortex™-M3/M4 Instruction Set Technical User's Manual for more information.
2.7.1.2
Wait for Event
The wait for event instruction, WFE, causes entry to sleep mode conditional on the value of a one-bit
event register. When the processor executes a WFE instruction, it checks the event register. If the
register is 0, the processor stops executing instructions and enters sleep mode. If the register is 1,
the processor clears the register and continues executing instructions without entering sleep mode.
If the event register is 1, the processor must not enter sleep mode on execution of a WFE instruction.
Typically, this situation occurs if an SEV instruction has been executed. Software cannot access
this register directly.
See the Cortex™-M3/M4 Instruction Set Technical User's Manual for more information.
2.7.1.3
Sleep-on-Exit
If the SLEEPEXIT bit of the SYSCTRL register is set, when the processor completes the execution
of all exception handlers, it returns to Thread mode and immediately enters sleep mode. This
mechanism can be used in applications that only require the processor to run when an exception
occurs.
2.7.2
Wake Up from Sleep Mode
The conditions for the processor to wake up depend on the mechanism that cause it to enter sleep
mode.
2.7.2.1
Wake Up from WFI or Sleep-on-Exit
Normally, the processor wakes up only when the NVIC detects an exception with sufficient priority
to cause exception entry. Some embedded systems might have to execute system restore tasks
after the processor wakes up and before executing an interrupt handler. Entry to the interrupt handler
can be delayed by setting the PRIMASK bit and clearing the FAULTMASK bit. If an interrupt arrives
that is enabled and has a higher priority than current exception priority, the processor wakes up but
does not execute the interrupt handler until the processor clears PRIMASK. For more information
about PRIMASK and FAULTMASK, see page 90 and page 91.
2.7.2.2
Wake Up from WFE
The processor wakes up if it detects an exception with sufficient priority to cause exception entry.
In addition, if the SEVONPEND bit in the SYSCTRL register is set, any new pending interrupt triggers
an event and wakes up the processor, even if the interrupt is disabled or has insufficient priority to
cause exception entry. For more information about SYSCTRL, see page 155.
114
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
2.8
Instruction Set Summary
The processor implements a version of the Thumb instruction set. Table 2-13 on page 115 lists the
supported instructions.
Note:
In Table 2-13 on page 115:
■
■
■
■
■
Angle brackets, <>, enclose alternative forms of the operand
Braces, {}, enclose optional operands
The Operands column is not exhaustive
Op2 is a flexible second operand that can be either a register or a constant
Most instructions can use an optional condition code suffix
For more information on the instructions and operands, see the instruction descriptions in
the Cortex™-M3/M4 Instruction Set Technical User's Manual.
Table 2-13. Cortex-M3 Instruction Summary
Mnemonic
Operands
Brief Description
Flags
ADC, ADCS
{Rd,} Rn, Op2
Add with carry
N,Z,C,V
ADD, ADDS
{Rd,} Rn, Op2
Add
N,Z,C,V
ADD, ADDW
{Rd,} Rn , #imm12
Add
N,Z,C,V
ADR
Rd, label
Load PC-relative address
-
AND, ANDS
{Rd,} Rn, Op2
Logical AND
N,Z,C
ASR, ASRS
Rd, Rm, <Rs|#n>
Arithmetic shift right
N,Z,C
B
label
Branch
-
BFC
Rd, #lsb, #width
Bit field clear
-
BFI
Rd, Rn, #lsb, #width
Bit field insert
-
BIC, BICS
{Rd,} Rn, Op2
Bit clear
N,Z,C
BKPT
#imm
Breakpoint
-
BL
label
Branch with link
-
BLX
Rm
Branch indirect with link
-
BX
Rm
Branch indirect
-
CBNZ
Rn, label
Compare and branch if non-zero
-
CBZ
Rn, label
Compare and branch if zero
-
CLREX
-
Clear exclusive
-
CLZ
Rd, Rm
Count leading zeros
-
CMN
Rn, Op2
Compare negative
N,Z,C,V
CMP
Rn, Op2
Compare
N,Z,C,V
CPSID
i
Change processor state, disable
interrupts
-
CPSIE
i
Change processor state, enable
interrupts
-
DMB
-
Data memory barrier
-
DSB
-
Data synchronization barrier
-
EOR, EORS
{Rd,} Rn, Op2
Exclusive OR
N,Z,C
ISB
-
Instruction synchronization barrier
-
IT
-
If-Then condition block
-
July 03, 2014
115
Texas Instruments-Production Data
The Cortex-M3 Processor
Table 2-13. Cortex-M3 Instruction Summary (continued)
Mnemonic
Operands
Brief Description
LDM
Rn{!}, reglist
Load multiple registers, increment after -
LDMDB, LDMEA
Rn{!}, reglist
Load multiple registers, decrement
before
LDMFD, LDMIA
Rn{!}, reglist
Load multiple registers, increment after -
LDR
Rt, [Rn, #offset]
Load register with word
-
LDRB, LDRBT
Rt, [Rn, #offset]
Load register with byte
-
LDRD
Rt, Rt2, [Rn, #offset]
Load register with two bytes
-
LDREX
Rt, [Rn, #offset]
Load register exclusive
-
LDREXB
Rt, [Rn]
Load register exclusive with byte
-
LDREXH
Rt, [Rn]
Load register exclusive with halfword
-
LDRH, LDRHT
Rt, [Rn, #offset]
Load register with halfword
-
LDRSB, LDRSBT
Rt, [Rn, #offset]
Load register with signed byte
-
LDRSH, LDRSHT
Rt, [Rn, #offset]
Load register with signed halfword
-
LDRT
Rt, [Rn, #offset]
Load register with word
-
LSL, LSLS
Rd, Rm, <Rs|#n>
Logical shift left
N,Z,C
LSR, LSRS
Rd, Rm, <Rs|#n>
Logical shift right
N,Z,C
MLA
Rd, Rn, Rm, Ra
Multiply with accumulate, 32-bit result
-
MLS
Rd, Rn, Rm, Ra
Multiply and subtract, 32-bit result
-
MOV, MOVS
Rd, Op2
Move
N,Z,C
MOV, MOVW
Rd, #imm16
Move 16-bit constant
N,Z,C
MOVT
Rd, #imm16
Move top
-
MRS
Rd, spec_reg
Move from special register to general
register
-
MSR
spec_reg, Rm
Move from general register to special
register
N,Z,C,V
MUL, MULS
{Rd,} Rn, Rm
Multiply, 32-bit result
N,Z
MVN, MVNS
Rd, Op2
Move NOT
N,Z,C
NOP
-
No operation
-
ORN, ORNS
{Rd,} Rn, Op2
Logical OR NOT
N,Z,C
ORR, ORRS
{Rd,} Rn, Op2
Logical OR
N,Z,C
POP
reglist
Pop registers from stack
-
PUSH
reglist
Push registers onto stack
-
RBIT
Rd, Rn
Reverse bits
-
REV
Rd, Rn
Reverse byte order in a word
-
REV16
Rd, Rn
Reverse byte order in each halfword
-
REVSH
Rd, Rn
Reverse byte order in bottom halfword
and sign extend
-
ROR, RORS
Rd, Rm, <Rs|#n>
Rotate right
N,Z,C
RRX, RRXS
Rd, Rm
Rotate right with extend
N,Z,C
RSB, RSBS
{Rd,} Rn, Op2
Reverse subtract
N,Z,C,V
SBC, SBCS
{Rd,} Rn, Op2
Subtract with carry
N,Z,C,V
SBFX
Rd, Rn, #lsb, #width
Signed bit field extract
-
116
Flags
-
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 2-13. Cortex-M3 Instruction Summary (continued)
Mnemonic
Operands
Brief Description
Flags
SDIV
{Rd,} Rn, Rm
Signed divide
-
SEV
-
Send event
-
SMLAL
RdLo, RdHi, Rn, Rm
Signed multiply with accumulate
(32x32+64), 64-bit result
-
SMULL
RdLo, RdHi, Rn, Rm
Signed multiply (32x32), 64-bit result
-
SSAT
Rd, #n, Rm {,shift #s}
Signed saturate
Q
STM
Rn{!}, reglist
Store multiple registers, increment after -
STMDB, STMEA
Rn{!}, reglist
Store multiple registers, decrement
before
STMFD, STMIA
Rn{!}, reglist
Store multiple registers, increment after -
STR
Rt, [Rn {, #offset}]
Store register word
-
STRB, STRBT
Rt, [Rn {, #offset}]
Store register byte
-
STRD
Rt, Rt2, [Rn {, #offset}]
Store register two words
-
STREX
Rt, Rt, [Rn {, #offset}]
Store register exclusive
-
STREXB
Rd, Rt, [Rn]
Store register exclusive byte
-
STREXH
Rd, Rt, [Rn]
Store register exclusive halfword
-
STRH, STRHT
Rt, [Rn {, #offset}]
Store register halfword
-
STRSB, STRSBT
Rt, [Rn {, #offset}]
Store register signed byte
-
STRSH, STRSHT
Rt, [Rn {, #offset}]
Store register signed halfword
-
STRT
Rt, [Rn {, #offset}]
Store register word
-
SUB, SUBS
{Rd,} Rn, Op2
Subtract
N,Z,C,V
SUB, SUBW
{Rd,} Rn, #imm12
Subtract 12-bit constant
N,Z,C,V
SVC
#imm
Supervisor call
-
SXTB
{Rd,} Rm {,ROR #n}
Sign extend a byte
-
SXTH
{Rd,} Rm {,ROR #n}
Sign extend a halfword
-
TBB
[Rn, Rm]
Table branch byte
-
TBH
[Rn, Rm, LSL #1]
Table branch halfword
-
TEQ
Rn, Op2
Test equivalence
N,Z,C
TST
Rn, Op2
Test
N,Z,C
UBFX
Rd, Rn, #lsb, #width
Unsigned bit field extract
-
UDIV
{Rd,} Rn, Rm
Unsigned divide
-
UMLAL
RdLo, RdHi, Rn, Rm
Unsigned multiply with accumulate
(32x32+32+32), 64-bit result
-
UMULL
RdLo, RdHi, Rn, Rm
Unsigned multiply (32x 2), 64-bit result -
USAT
Rd, #n, Rm {,shift #s}
Unsigned Saturate
Q
UXTB
{Rd,} Rm, {,ROR #n}
Zero extend a Byte
-
UXTH
{Rd,} Rm, {,ROR #n}
Zero extend a Halfword
-
WFE
-
Wait for event
-
WFI
-
Wait for interrupt
-
July 03, 2014
-
117
Texas Instruments-Production Data
Cortex-M3 Peripherals
3
Cortex-M3 Peripherals
®
This chapter provides information on the Stellaris implementation of the Cortex-M3 processor
peripherals, including:
■ SysTick (see page 118)
Provides a simple, 24-bit clear-on-write, decrementing, wrap-on-zero counter with a flexible
control mechanism.
■ Nested Vectored Interrupt Controller (NVIC) (see page 119)
– Facilitates low-latency exception and interrupt handling
– Controls power management
– Implements system control registers
■ System Control Block (SCB) (see page 121)
Provides system implementation information and system control, including configuration, control,
and reporting of system exceptions.
■ Memory Protection Unit (MPU) (see page 121)
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.
Table 3-1 on page 118 shows the address map of the Private Peripheral Bus (PPB). Some peripheral
register regions are split into two address regions, as indicated by two addresses listed.
Table 3-1. Core Peripheral Register Regions
Address
Core Peripheral
Description (see page ...)
0xE000.E010-0xE000.E01F
System Timer
118
0xE000.E100-0xE000.E4EF
Nested Vectored Interrupt Controller
119
System Control Block
121
Memory Protection Unit
121
0xE000.EF00-0xE000.EF03
0xE000.E008-0xE000.E00F
0xE000.ED00-0xE000.ED3F
0xE000.ED90-0xE000.EDB8
3.1
Functional Description
This chapter provides information on the Stellaris implementation of the Cortex-M3 processor
peripherals: SysTick, NVIC, SCB and MPU.
3.1.1
System Timer (SysTick)
Cortex-M3 includes an integrated system timer, SysTick, which provides a simple, 24-bit
clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter
can be used in several different ways, for example as:
■ An RTOS tick timer that fires at a programmable rate (for example, 100 Hz) and invokes a SysTick
routine.
■ A high-speed alarm timer using the system clock.
118
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ A variable rate alarm or signal timer—the duration is range-dependent on the reference clock
used and the dynamic range of the counter.
■ A simple counter used to measure time to completion and time used.
■ An internal clock source control based on missing/meeting durations. The COUNT bit in the
STCTRL control and status register can be used to determine if an action completed within a
set duration, as part of a dynamic clock management control loop.
The timer consists of three registers:
■ SysTick Control and Status (STCTRL): A control and status counter to configure its clock,
enable the counter, enable the SysTick interrupt, and determine counter status.
■ SysTick Reload Value (STRELOAD): The reload value for the counter, used to provide the
counter's wrap value.
■ SysTick Current Value (STCURRENT): The current value of the counter.
When enabled, the timer counts down on each clock from the reload value to zero, reloads (wraps)
to the value in the STRELOAD register on the next clock edge, then decrements on subsequent
clocks. Clearing the STRELOAD register disables the counter on the next wrap. When the counter
reaches zero, the COUNT status bit is set. The COUNT bit clears on reads.
Writing to the STCURRENT register clears the register and the COUNT status bit. The write does
not trigger the SysTick exception logic. On a read, the current value is the value of the register at
the time the register is accessed.
The SysTick counter runs on the system clock. If this clock signal is stopped for low power mode,
the SysTick counter stops. Ensure software uses aligned word accesses to access the SysTick
registers.
Note:
3.1.2
When the processor is halted for debugging, the counter does not decrement.
Nested Vectored Interrupt Controller (NVIC)
This section describes the Nested Vectored Interrupt Controller (NVIC) and the registers it uses.
The NVIC supports:
■ 52 interrupts.
■ A programmable priority level of 0-7 for each interrupt. A higher level corresponds to a lower
priority, so level 0 is the highest interrupt priority.
■ Low-latency exception and interrupt handling.
■ Level and pulse detection of interrupt signals.
■ Dynamic reprioritization of interrupts.
■ Grouping of priority values into group priority and subpriority fields.
■ Interrupt tail-chaining.
■ An external Non-maskable interrupt (NMI).
July 03, 2014
119
Texas Instruments-Production Data
Cortex-M3 Peripherals
The processor automatically stacks its state on exception entry and unstacks this state on exception
exit, with no instruction overhead, providing low latency exception handling.
3.1.2.1
Level-Sensitive and Pulse Interrupts
The processor supports both level-sensitive and pulse interrupts. Pulse interrupts are also described
as edge-triggered interrupts.
A level-sensitive interrupt is held asserted until the peripheral deasserts the interrupt signal. Typically
this happens because the ISR accesses the peripheral, causing it to clear the interrupt request. A
pulse interrupt is an interrupt signal sampled synchronously on the rising edge of the processor
clock. To ensure the NVIC detects the interrupt, the peripheral must assert the interrupt signal for
at least one clock cycle, during which the NVIC detects the pulse and latches the interrupt.
When the processor enters the ISR, it automatically removes the pending state from the interrupt
(see “Hardware and Software Control of Interrupts” on page 120 for more information). For a
level-sensitive interrupt, if the signal is not deasserted before the processor returns from the ISR,
the interrupt becomes pending again, and the processor must execute its ISR again. As a result,
the peripheral can hold the interrupt signal asserted until it no longer needs servicing.
3.1.2.2
Hardware and Software Control of Interrupts
The Cortex-M3 latches all interrupts. A peripheral interrupt becomes pending for one of the following
reasons:
■ The NVIC detects that the interrupt signal is High and the interrupt is not active.
■ The NVIC detects a rising edge on the interrupt signal.
■ Software writes to the corresponding interrupt set-pending register bit, or to the Software Trigger
Interrupt (SWTRIG) register to make a Software-Generated Interrupt pending. See the INT bit
in the PEND0 register on page 137 or SWTRIG on page 145.
A pending interrupt remains pending until one of the following:
■ The processor enters the ISR for the interrupt, changing the state of the interrupt from pending
to active. Then:
– For a level-sensitive interrupt, when the processor returns from the ISR, the NVIC samples
the interrupt signal. If the signal is asserted, the state of the interrupt changes to pending,
which might cause the processor to immediately re-enter the ISR. Otherwise, the state of the
interrupt changes to inactive.
– For a pulse interrupt, the NVIC continues to monitor the interrupt signal, and if this is pulsed
the state of the interrupt changes to pending and active. In this case, when the processor
returns from the ISR the state of the interrupt changes to pending, which might cause the
processor to immediately re-enter the ISR.
If the interrupt signal is not pulsed while the processor is in the ISR, when the processor
returns from the ISR the state of the interrupt changes to inactive.
■ Software writes to the corresponding interrupt clear-pending register bit
– For a level-sensitive interrupt, if the interrupt signal is still asserted, the state of the interrupt
does not change. Otherwise, the state of the interrupt changes to inactive.
120
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
– For a pulse interrupt, the state of the interrupt changes to inactive, if the state was pending
or to active, if the state was active and pending.
3.1.3
System Control Block (SCB)
The System Control Block (SCB) provides system implementation information and system control,
including configuration, control, and reporting of the system exceptions.
3.1.4
Memory Protection Unit (MPU)
This section describes the Memory protection unit (MPU). The MPU divides the memory map into
a number of regions and defines the location, size, access permissions, and memory attributes of
each region. The MPU supports independent attribute settings for each region, overlapping regions,
and export of memory attributes to the system.
The memory attributes affect the behavior of memory accesses to the region. The Cortex-M3 MPU
defines eight separate memory regions, 0-7, and a background region.
When memory regions overlap, a memory access is affected by the attributes of the region with the
highest number. For example, the attributes for region 7 take precedence over the attributes of any
region that overlaps region 7.
The background region has the same memory access attributes as the default memory map, but is
accessible from privileged software only.
The Cortex-M3 MPU memory map is unified, meaning that instruction accesses and data accesses
have the same region settings.
If a program accesses a memory location that is prohibited by the MPU, the processor generates
a memory management fault, causing a fault exception and possibly causing termination of the
process in an OS environment. In an OS environment, the kernel can update the MPU region setting
dynamically based on the process to be executed. Typically, an embedded OS uses the MPU for
memory protection.
Configuration of MPU regions is based on memory types (see “Memory Regions, Types and
Attributes” on page 96 for more information).
Table 3-2 on page 121 shows the possible MPU region attributes. See the section called “MPU
Configuration for a Stellaris Microcontroller” on page 125 for guidelines for programming a
microcontroller implementation.
Table 3-2. Memory Attributes Summary
Memory Type
Description
Strongly Ordered
All accesses to Strongly Ordered memory occur in program order.
Device
Memory-mapped peripherals
Normal
Normal memory
To avoid unexpected behavior, disable the interrupts before updating the attributes of a region that
the interrupt handlers might access.
Ensure software uses aligned accesses of the correct size to access MPU registers:
■ Except for the MPU Region Attribute and Size (MPUATTR) register, all MPU registers must
be accessed with aligned word accesses.
■ The MPUATTR register can be accessed with byte or aligned halfword or word accesses.
July 03, 2014
121
Texas Instruments-Production Data
Cortex-M3 Peripherals
The processor does not support unaligned accesses to MPU registers.
When setting up the MPU, and if the MPU has previously been programmed, disable unused regions
to prevent any previous region settings from affecting the new MPU setup.
3.1.4.1
Updating an MPU Region
To update the attributes for an MPU region, the MPU Region Number (MPUNUMBER), MPU
Region Base Address (MPUBASE) and MPUATTR registers must be updated. Each register can
be programmed separately or with a multiple-word write to program all of these registers. You can
use the MPUBASEx and MPUATTRx aliases to program up to four regions simultaneously using
an STM instruction.
Updating an MPU Region Using Separate Words
This example simple code configures one region:
; R1 = region number
; R2 = size/enable
; R3 = attributes
; R4 = address
LDR R0,=MPUNUMBER
STR R1, [R0, #0x0]
STR R4, [R0, #0x4]
STRH R2, [R0, #0x8]
STRH R3, [R0, #0xA]
;
;
;
;
;
0xE000ED98, MPU region number register
Region Number
Region Base Address
Region Size and Enable
Region Attribute
Disable a region before writing new region settings to the MPU if you have previously enabled the
region being changed. For example:
; R1 = region number
; R2 = size/enable
; R3 = attributes
; R4 = address
LDR R0,=MPUNUMBER
STR R1, [R0, #0x0]
BIC R2, R2, #1
STRH R2, [R0, #0x8]
STR R4, [R0, #0x4]
STRH R3, [R0, #0xA]
ORR R2, #1
STRH R2, [R0, #0x8]
;
;
;
;
;
;
;
;
0xE000ED98, MPU region number register
Region Number
Disable
Region Size and Enable
Region Base Address
Region Attribute
Enable
Region Size and Enable
Software must use memory barrier instructions:
■ Before MPU setup, if there might be outstanding memory transfers, such as buffered writes, that
might be affected by the change in MPU settings.
■ After MPU setup, if it includes memory transfers that must use the new MPU settings.
However, memory barrier instructions are not required if the MPU setup process starts by entering
an exception handler, or is followed by an exception return, because the exception entry and
exception return mechanism cause memory barrier behavior.
Software does not need any memory barrier instructions during MPU setup, because it accesses
the MPU through the Private Peripheral Bus (PPB), which is a Strongly Ordered memory region.
122
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
For example, if all of the memory access behavior is intended to take effect immediately after the
programming sequence, then a DSB instruction and an ISB instruction should be used. A DSB is
required after changing MPU settings, such as at the end of context switch. An ISB is required if
the code that programs the MPU region or regions is entered using a branch or call. If the
programming sequence is entered using a return from exception, or by taking an exception, then
an ISB is not required.
Updating an MPU Region Using Multi-Word Writes
The MPU can be programmed directly using multi-word writes, depending how the information is
divided. Consider the following reprogramming:
; R1 = region number
; R2 = address
; R3 = size, attributes in one
LDR R0, =MPUNUMBER ; 0xE000ED98, MPU region number register
STR R1, [R0, #0x0] ; Region Number
STR R2, [R0, #0x4] ; Region Base Address
STR R3, [R0, #0x8] ; Region Attribute, Size and Enable
An STM instruction can be used to optimize this:
; R1 = region number
; R2 = address
; R3 = size, attributes in one
LDR R0, =MPUNUMBER ; 0xE000ED98, MPU region number register
STM R0, {R1-R3}
; Region number, address, attribute, size and enable
This operation can be done in two words for pre-packed information, meaning that the MPU Region
Base Address (MPUBASE) register (see page 179) contains the required region number and has
the VALID bit set. This method can be used when the data is statically packed, for example in a
boot loader:
; R1 = address and region number in one
; R2 = size and attributes in one
LDR R0, =MPUBASE
; 0xE000ED9C, MPU Region Base register
STR R1, [R0, #0x0] ; Region base address and region number combined
; with VALID (bit 4) set
STR R2, [R0, #0x4] ; Region Attribute, Size and Enable
Subregions
Regions of 256 bytes or more are divided into eight equal-sized subregions. Set the corresponding
bit in the SRD field of the MPU Region Attribute and Size (MPUATTR) register (see page 181) to
disable a subregion. The least-significant bit of the SRD field controls the first subregion, and the
most-significant bit controls the last subregion. Disabling a subregion means another region
overlapping the disabled range matches instead. If no other enabled region overlaps the disabled
subregion, the MPU issues a fault.
Regions of 32, 64, and 128 bytes do not support subregions. With regions of these sizes, the SRD
field must be configured to 0x00, otherwise the MPU behavior is unpredictable.
July 03, 2014
123
Texas Instruments-Production Data
Cortex-M3 Peripherals
Example of SRD Use
Two regions with the same base address overlap. Region one is 128 KB, and region two is 512 KB.
To ensure the attributes from region one apply to the first 128 KB region, configure the SRD field for
region two to 0x03 to disable the first two subregions, as Figure 3-1 on page 124 shows.
Figure 3-1. SRD Use Example
Region 2, with
subregions
Region 1
Base address of both regions
3.1.4.2
Offset from
base address
512KB
448KB
384KB
320KB
256KB
192KB
128KB
Disabled subregion
64KB
Disabled subregion
0
MPU Access Permission Attributes
The access permission bits, TEX, S, C, B, AP, and XN of the MPUATTR register, control access to
the corresponding memory region. If an access is made to an area of memory without the required
permissions, then the MPU generates a permission fault.
Table 3-3 on page 124 shows the encodings for the TEX, C, B, and S access permission bits. All
encodings are shown for completeness, however the current implementation of the Cortex-M3 does
not support the concept of cacheability or shareability. Refer to the section called “MPU Configuration
for a Stellaris Microcontroller” on page 125 for information on programming the MPU for Stellaris
implementations.
Table 3-3. TEX, S, C, and B Bit Field Encoding
TEX
S
000b
x
C
B
Memory Type
Shareability
Other Attributes
a
0
0
Strongly Ordered
Shareable
-
a
-
000
x
0
1
Device
Shareable
000
0
1
0
Normal
Not shareable
000
1
1
0
Normal
Shareable
000
0
1
1
Normal
Not shareable
000
1
1
1
Normal
Shareable
001
0
0
0
Normal
Not shareable
001
1
0
0
Normal
Shareable
Outer and inner
noncacheable.
001
x
a
0
1
Reserved encoding
-
-
a
Outer and inner
write-through. No write
allocate.
001
x
1
0
Reserved encoding
-
-
001
0
1
1
Normal
Not shareable
001
1
1
1
Normal
Shareable
Outer and inner
write-back. Write and
read allocate.
010
x
a
0
0
Device
Not shareable
Nonshared Device.
a
0
1
Reserved encoding
-
-
a
1
x
Reserved encoding
-
-
010
x
010
x
a
124
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 3-3. TEX, S, C, and B Bit Field Encoding (continued)
TEX
S
C
B
Memory Type
Shareability
Other Attributes
1BB
0
A
A
Normal
Not shareable
1BB
1
A
A
Normal
Shareable
Cached memory (BB =
outer policy, AA = inner
policy).
See Table 3-4 for the
encoding of the AA and
BB bits.
a. The MPU ignores the value of this bit.
Table 3-4 on page 125 shows the cache policy for memory attribute encodings with a TEX value in
the range of 0x4-0x7.
Table 3-4. Cache Policy for Memory Attribute Encoding
Encoding, AA or BB
Corresponding Cache Policy
00
Non-cacheable
01
Write back, write and read allocate
10
Write through, no write allocate
11
Write back, no write allocate
Table 3-5 on page 125 shows the AP encodings in the MPUATTR register that define the access
permissions for privileged and unprivileged software.
Table 3-5. AP Bit Field Encoding
AP Bit Field
Privileged
Permissions
Unprivileged
Permissions
Description
000
No access
No access
All accesses generate a permission fault.
001
R/W
No access
Access from privileged software only.
010
R/W
RO
Writes by unprivileged software generate a
permission fault.
011
R/W
R/W
Full access.
100
Unpredictable
Unpredictable
Reserved.
101
RO
No access
Reads by privileged software only.
110
RO
RO
Read-only, by privileged or unprivileged software.
111
RO
RO
Read-only, by privileged or unprivileged software.
MPU Configuration for a Stellaris Microcontroller
Stellaris microcontrollers have only a single processor and no caches. As a result, the MPU should
be programmed as shown in Table 3-6 on page 125.
Table 3-6. Memory Region Attributes for Stellaris Microcontrollers
Memory Region
TEX
S
C
B
Memory Type and Attributes
Flash memory
000b
0
1
0
Normal memory, non-shareable, write-through
Internal SRAM
000b
1
1
0
Normal memory, shareable, write-through
External SRAM
000b
1
1
1
Normal memory, shareable, write-back,
write-allocate
Peripherals
000b
1
0
1
Device memory, shareable
July 03, 2014
125
Texas Instruments-Production Data
Cortex-M3 Peripherals
In current Stellaris microcontroller implementations, the shareability and cache policy attributes do
not affect the system behavior. However, using these settings for the MPU regions can make the
application code more portable. The values given are for typical situations.
3.1.4.3
MPU Mismatch
When an access violates the MPU permissions, the processor generates a memory management
fault (see “Exceptions and Interrupts” on page 94 for more information). The MFAULTSTAT register
indicates the cause of the fault. See page 166 for more information.
3.2
Register Map
Table 3-7 on page 126 lists the Cortex-M3 Peripheral SysTick, NVIC, MPU and SCB registers. The
offset listed is a hexadecimal increment to the register's address, relative to the Core Peripherals
base address of 0xE000.E000.
Note:
Register spaces that are not used are reserved for future or internal use. Software should
not modify any reserved memory address.
Table 3-7. Peripherals Register Map
Offset
Name
Type
Reset
Description
See
page
System Timer (SysTick) Registers
0x010
STCTRL
R/W
0x0000.0004
SysTick Control and Status Register
129
0x014
STRELOAD
R/W
0x0000.0000
SysTick Reload Value Register
131
0x018
STCURRENT
R/WC
0x0000.0000
SysTick Current Value Register
132
Nested Vectored Interrupt Controller (NVIC) Registers
0x100
EN0
R/W
0x0000.0000
Interrupt 0-31 Set Enable
133
0x104
EN1
R/W
0x0000.0000
Interrupt 32-54 Set Enable
134
0x180
DIS0
R/W
0x0000.0000
Interrupt 0-31 Clear Enable
135
0x184
DIS1
R/W
0x0000.0000
Interrupt 32-54 Clear Enable
136
0x200
PEND0
R/W
0x0000.0000
Interrupt 0-31 Set Pending
137
0x204
PEND1
R/W
0x0000.0000
Interrupt 32-54 Set Pending
138
0x280
UNPEND0
R/W
0x0000.0000
Interrupt 0-31 Clear Pending
139
0x284
UNPEND1
R/W
0x0000.0000
Interrupt 32-54 Clear Pending
140
0x300
ACTIVE0
RO
0x0000.0000
Interrupt 0-31 Active Bit
141
0x304
ACTIVE1
RO
0x0000.0000
Interrupt 32-54 Active Bit
142
0x400
PRI0
R/W
0x0000.0000
Interrupt 0-3 Priority
143
0x404
PRI1
R/W
0x0000.0000
Interrupt 4-7 Priority
143
0x408
PRI2
R/W
0x0000.0000
Interrupt 8-11 Priority
143
0x40C
PRI3
R/W
0x0000.0000
Interrupt 12-15 Priority
143
0x410
PRI4
R/W
0x0000.0000
Interrupt 16-19 Priority
143
126
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 3-7. Peripherals Register Map (continued)
Description
See
page
Offset
Name
Type
Reset
0x414
PRI5
R/W
0x0000.0000
Interrupt 20-23 Priority
143
0x418
PRI6
R/W
0x0000.0000
Interrupt 24-27 Priority
143
0x41C
PRI7
R/W
0x0000.0000
Interrupt 28-31 Priority
143
0x420
PRI8
R/W
0x0000.0000
Interrupt 32-35 Priority
143
0x424
PRI9
R/W
0x0000.0000
Interrupt 36-39 Priority
143
0x428
PRI10
R/W
0x0000.0000
Interrupt 40-43 Priority
143
0x42C
PRI11
R/W
0x0000.0000
Interrupt 44-47 Priority
143
0x430
PRI12
R/W
0x0000.0000
Interrupt 48-51 Priority
143
0x434
PRI13
R/W
0x0000.0000
Interrupt 52-54 Priority
143
0xF00
SWTRIG
WO
0x0000.0000
Software Trigger Interrupt
145
System Control Block (SCB) Registers
0x008
ACTLR
R/W
0x0000.0000
Auxiliary Control
146
0xD00
CPUID
RO
0x412F.C230
CPU ID Base
148
0xD04
INTCTRL
R/W
0x0000.0000
Interrupt Control and State
149
0xD08
VTABLE
R/W
0x0000.0000
Vector Table Offset
152
0xD0C
APINT
R/W
0xFA05.0000
Application Interrupt and Reset Control
153
0xD10
SYSCTRL
R/W
0x0000.0000
System Control
155
0xD14
CFGCTRL
R/W
0x0000.0200
Configuration and Control
157
0xD18
SYSPRI1
R/W
0x0000.0000
System Handler Priority 1
159
0xD1C
SYSPRI2
R/W
0x0000.0000
System Handler Priority 2
160
0xD20
SYSPRI3
R/W
0x0000.0000
System Handler Priority 3
161
0xD24
SYSHNDCTRL
R/W
0x0000.0000
System Handler Control and State
162
0xD28
FAULTSTAT
R/W1C
0x0000.0000
Configurable Fault Status
166
0xD2C
HFAULTSTAT
R/W1C
0x0000.0000
Hard Fault Status
172
0xD34
MMADDR
R/W
-
Memory Management Fault Address
173
0xD38
FAULTADDR
R/W
-
Bus Fault Address
174
Memory Protection Unit (MPU) Registers
0xD90
MPUTYPE
RO
0x0000.0800
MPU Type
175
0xD94
MPUCTRL
R/W
0x0000.0000
MPU Control
176
0xD98
MPUNUMBER
R/W
0x0000.0000
MPU Region Number
178
0xD9C
MPUBASE
R/W
0x0000.0000
MPU Region Base Address
179
0xDA0
MPUATTR
R/W
0x0000.0000
MPU Region Attribute and Size
181
July 03, 2014
127
Texas Instruments-Production Data
Cortex-M3 Peripherals
Table 3-7. Peripherals Register Map (continued)
Name
Type
Reset
0xDA4
MPUBASE1
R/W
0x0000.0000
MPU Region Base Address Alias 1
179
0xDA8
MPUATTR1
R/W
0x0000.0000
MPU Region Attribute and Size Alias 1
181
0xDAC
MPUBASE2
R/W
0x0000.0000
MPU Region Base Address Alias 2
179
0xDB0
MPUATTR2
R/W
0x0000.0000
MPU Region Attribute and Size Alias 2
181
0xDB4
MPUBASE3
R/W
0x0000.0000
MPU Region Base Address Alias 3
179
0xDB8
MPUATTR3
R/W
0x0000.0000
MPU Region Attribute and Size Alias 3
181
3.3
Description
See
page
Offset
System Timer (SysTick) Register Descriptions
This section lists and describes the System Timer registers, in numerical order by address offset.
128
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 1: SysTick Control and Status Register (STCTRL), offset 0x010
Note:
This register can only be accessed from privileged mode.
The SysTick STCTRL register enables the SysTick features.
SysTick Control and Status Register (STCTRL)
Base 0xE000.E000
Offset 0x010
Type R/W, reset 0x0000.0004
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
9
8
7
6
5
4
3
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
16
COUNT
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
2
1
0
CLK_SRC
INTEN
ENABLE
R/W
1
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:17
reserved
RO
0x000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
16
COUNT
RO
0
Count Flag
Value
Description
0
The SysTick timer has not counted to 0 since the last time
this bit was read.
1
The SysTick timer has counted to 0 since the last time
this bit was read.
This bit is cleared by a read of the register or if the STCURRENT register
is written with any value.
If read by the debugger using the DAP, this bit is cleared only if the
MasterType bit in the AHB-AP Control Register is clear. Otherwise,
the COUNT bit is not changed by the debugger read. See the ARM®
Debug Interface V5 Architecture Specification for more information on
MasterType.
15:3
reserved
RO
0x000
2
CLK_SRC
R/W
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.
Clock Source
Value Description
0
External reference clock. (Not implemented for most Stellaris
microcontrollers.)
1
System clock
Because an external reference clock is not implemented, this bit must
be set in order for SysTick to operate.
July 03, 2014
129
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
1
INTEN
R/W
0
0
ENABLE
R/W
0
Description
Interrupt Enable
Value
Description
0
Interrupt generation is disabled. Software can use the
COUNT bit to determine if the counter has ever reached 0.
1
An interrupt is generated to the NVIC when SysTick counts
to 0.
Enable
Value
Description
0
The counter is disabled.
1
Enables SysTick to operate in a multi-shot way. That is, the
counter loads the RELOAD value and begins counting down.
On reaching 0, the COUNT bit is set and an interrupt is
generated if enabled by INTEN. The counter then loads the
RELOAD value again and begins counting.
130
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 2: SysTick Reload Value Register (STRELOAD), offset 0x014
Note:
This register can only be accessed from privileged mode.
The STRELOAD register specifies the start value to load into the SysTick Current Value
(STCURRENT) register when the counter reaches 0. The start value can be between 0x1 and
0x00FF.FFFF. A start value of 0 is possible but has no effect because the SysTick interrupt and the
COUNT bit are activated when counting from 1 to 0.
SysTick can be configured as a multi-shot timer, repeated over and over, firing every N+1 clock
pulses, where N is any value from 1 to 0x00FF.FFFF. For example, if a tick interrupt is required
every 100 clock pulses, 99 must be written into the RELOAD field.
SysTick Reload Value Register (STRELOAD)
Base 0xE000.E000
Offset 0x014
Type R/W, reset 0x0000.0000
31
30
29
28
RO
0
RO
0
RO
0
RO
0
15
14
13
R/W
0
R/W
0
R/W
0
27
26
25
24
23
22
21
20
18
17
16
RO
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
R/W
0
R/W
0
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
reserved
Type
Reset
19
RELOAD
RELOAD
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:24
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
23:0
RELOAD
R/W
0x00.0000
Reload Value
Value to load into the SysTick Current Value (STCURRENT) register
when the counter reaches 0.
July 03, 2014
131
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 3: SysTick Current Value Register (STCURRENT), offset 0x018
Note:
This register can only be accessed from privileged mode.
The STCURRENT register contains the current value of the SysTick counter.
SysTick Current Value Register (STCURRENT)
Base 0xE000.E000
Offset 0x018
Type R/WC, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
reserved
Type
Reset
20
19
18
17
16
CURRENT
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
CURRENT
Type
Reset
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
R/WC
0
Bit/Field
Name
Type
Reset
Description
31:24
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
23:0
CURRENT
R/WC
0x00.0000
Current Value
This field contains the 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.
Clearing this register also clears the COUNT bit of the STCTRL register.
3.4
NVIC Register Descriptions
This section lists and describes the NVIC registers, in numerical order by address offset.
The NVIC registers can only be fully accessed from privileged mode, but interrupts can be pended
while in unprivileged mode by enabling the Configuration and Control (CFGCTRL) register. Any
other unprivileged mode access causes a bus fault.
Ensure software uses correctly aligned register accesses. The processor does not support unaligned
accesses to NVIC registers.
An interrupt can enter the pending state even if it is disabled.
Before programming the VTABLE register to relocate the vector table, ensure the vector table
entries of the new vector table are set up for fault handlers, NMI, and all enabled exceptions such
as interrupts. For more information, see page 152.
132
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 4: Interrupt 0-31 Set Enable (EN0), offset 0x100
Note:
This register can only be accessed from privileged mode.
The EN0 register enables interrupts and shows which interrupts are enabled. Bit 0 corresponds to
Interrupt 0; bit 31 corresponds to Interrupt 31.
See Table 2-9 on page 106 for interrupt assignments.
If a pending interrupt is enabled, the NVIC activates the interrupt based on its priority. If an interrupt
is not enabled, asserting its interrupt signal changes the interrupt state to pending, but the NVIC
never activates the interrupt, regardless of its priority.
Interrupt 0-31 Set Enable (EN0)
Base 0xE000.E000
Offset 0x100
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
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
INT
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
INT
Type
Reset
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
31:0
INT
R/W
R/W
0
Reset
R/W
0
Description
0x0000.0000 Interrupt Enable
Value
Description
0
On a read, indicates the interrupt is disabled.
On a write, no effect.
1
On a read, indicates the interrupt is enabled.
On a write, enables the interrupt.
A bit can only be cleared by setting the corresponding INT[n] bit in
the DISn register.
July 03, 2014
133
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 5: Interrupt 32-54 Set Enable (EN1), offset 0x104
Note:
This register can only be accessed from privileged mode.
The EN1 register enables interrupts and shows which interrupts are enabled. Bit 0 corresponds to
Interrupt 32; bit 22 corresponds to Interrupt 54. See Table 2-9 on page 106 for interrupt assignments.
If a pending interrupt is enabled, the NVIC activates the interrupt based on its priority. If an interrupt
is not enabled, asserting its interrupt signal changes the interrupt state to pending, but the NVIC
never activates the interrupt, regardless of its priority.
Interrupt 32-54 Set Enable (EN1)
Base 0xE000.E000
Offset 0x104
Type R/W, reset 0x0000.0000
31
30
29
28
RO
0
RO
0
RO
0
RO
0
15
14
13
R/W
0
R/W
0
R/W
0
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
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
R/W
0
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
reserved
Type
Reset
INT
INT
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:23
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.
22:0
INT
R/W
0x00.0000
Interrupt Enable
Value
Description
0
On a read, indicates the interrupt is disabled.
On a write, no effect.
1
On a read, indicates the interrupt is enabled.
On a write, enables the interrupt.
A bit can only be cleared by setting the corresponding INT[n] bit in
the DIS1 register.
134
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 6: Interrupt 0-31 Clear Enable (DIS0), offset 0x180
Note:
This register can only be accessed from privileged mode.
The DIS0 register disables interrupts. Bit 0 corresponds to Interrupt 0; bit 31 corresponds to Interrupt
31.
See Table 2-9 on page 106 for interrupt assignments.
Interrupt 0-31 Clear Enable (DIS0)
Base 0xE000.E000
Offset 0x180
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
INT
Type
Reset
INT
Type
Reset
Bit/Field
Name
Type
31:0
INT
R/W
Reset
Description
0x0000.0000 Interrupt Disable
Value Description
0
On a read, indicates the interrupt is disabled.
On a write, no effect.
1
On a read, indicates the interrupt is enabled.
On a write, clears the corresponding INT[n] bit in the EN0
register, disabling interrupt [n].
July 03, 2014
135
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 7: Interrupt 32-54 Clear Enable (DIS1), offset 0x184
Note:
This register can only be accessed from privileged mode.
The DIS1 register disables interrupts. Bit 0 corresponds to Interrupt 32; bit 22 corresponds to Interrupt
54. See Table 2-9 on page 106 for interrupt assignments.
Interrupt 32-54 Clear Enable (DIS1)
Base 0xE000.E000
Offset 0x184
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
reserved
Type
Reset
19
18
17
16
INT
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
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
INT
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
31:23
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.
22:0
INT
R/W
0x00.0000
Interrupt Disable
Value Description
0
On a read, indicates the interrupt is disabled.
On a write, no effect.
1
On a read, indicates the interrupt is enabled.
On a write, clears the corresponding INT[n] bit in the EN1
register, disabling interrupt [n].
136
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 8: Interrupt 0-31 Set Pending (PEND0), offset 0x200
Note:
This register can only be accessed from privileged mode.
The PEND0 register forces interrupts into the pending state and shows which interrupts are pending.
Bit 0 corresponds to Interrupt 0; bit 31 corresponds to Interrupt 31.
See Table 2-9 on page 106 for interrupt assignments.
Interrupt 0-31 Set Pending (PEND0)
Base 0xE000.E000
Offset 0x200
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
INT
Type
Reset
INT
Type
Reset
Bit/Field
Name
Type
31:0
INT
R/W
Reset
Description
0x0000.0000 Interrupt Set Pending
Value
Description
0
On a read, indicates that the interrupt is not pending.
On a write, no effect.
1
On a read, indicates that the interrupt is pending.
On a write, the corresponding interrupt is set to pending
even if it is disabled.
If the corresponding interrupt is already pending, setting a bit has no
effect.
A bit can only be cleared by setting the corresponding INT[n] bit in
the UNPEND0 register.
July 03, 2014
137
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 9: Interrupt 32-54 Set Pending (PEND1), offset 0x204
Note:
This register can only be accessed from privileged mode.
The PEND1 register forces interrupts into the pending state and shows which interrupts are pending.
Bit 0 corresponds to Interrupt 32; bit 22 corresponds to Interrupt 54. See Table 2-9 on page 106 for
interrupt assignments.
Interrupt 32-54 Set Pending (PEND1)
Base 0xE000.E000
Offset 0x204
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
reserved
Type
Reset
19
18
17
16
INT
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
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
INT
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
31:23
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.
22:0
INT
R/W
0x00.0000
Interrupt Set Pending
Value
Description
0
On a read, indicates that the interrupt is not pending.
On a write, no effect.
1
On a read, indicates that the interrupt is pending.
On a write, the corresponding interrupt is set to pending
even if it is disabled.
If the corresponding interrupt is already pending, setting a bit has no
effect.
A bit can only be cleared by setting the corresponding INT[n] bit in
the UNPEND1 register.
138
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 10: Interrupt 0-31 Clear Pending (UNPEND0), offset 0x280
Note:
This register can only be accessed from privileged mode.
The UNPEND0 register shows which interrupts are pending and removes the pending state from
interrupts. Bit 0 corresponds to Interrupt 0; bit 31 corresponds to Interrupt 31.
See Table 2-9 on page 106 for interrupt assignments.
Interrupt 0-31 Clear Pending (UNPEND0)
Base 0xE000.E000
Offset 0x280
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
INT
Type
Reset
INT
Type
Reset
Bit/Field
Name
Type
31:0
INT
R/W
Reset
Description
0x0000.0000 Interrupt Clear Pending
Value Description
0
On a read, indicates that the interrupt is not pending.
On a write, no effect.
1
On a read, indicates that the interrupt is pending.
On a write, clears the corresponding INT[n] bit in the PEND0
register, so that interrupt [n] is no longer pending.
Setting a bit does not affect the active state of the corresponding
interrupt.
July 03, 2014
139
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 11: Interrupt 32-54 Clear Pending (UNPEND1), offset 0x284
Note:
This register can only be accessed from privileged mode.
The UNPEND1 register shows which interrupts are pending and removes the pending state from
interrupts. Bit 0 corresponds to Interrupt 32; bit 22 corresponds to Interrupt 54. See Table
2-9 on page 106 for interrupt assignments.
Interrupt 32-54 Clear Pending (UNPEND1)
Base 0xE000.E000
Offset 0x284
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
reserved
Type
Reset
19
18
17
16
INT
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
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
INT
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
31:23
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.
22:0
INT
R/W
0x00.0000
Interrupt Clear Pending
Value Description
0
On a read, indicates that the interrupt is not pending.
On a write, no effect.
1
On a read, indicates that the interrupt is pending.
On a write, clears the corresponding INT[n] bit in the PEND1
register, so that interrupt [n] is no longer pending.
Setting a bit does not affect the active state of the corresponding
interrupt.
140
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 12: Interrupt 0-31 Active Bit (ACTIVE0), offset 0x300
Note:
This register can only be accessed from privileged mode.
The ACTIVE0 register indicates which interrupts are active. Bit 0 corresponds to Interrupt 0; bit 31
corresponds to Interrupt 31.
See Table 2-9 on page 106 for interrupt assignments.
Caution – Do not manually set or clear the bits in this register.
Interrupt 0-31 Active Bit (ACTIVE0)
Base 0xE000.E000
Offset 0x300
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
INT
Type
Reset
INT
Type
Reset
Bit/Field
Name
Type
31:0
INT
RO
Reset
Description
0x0000.0000 Interrupt Active
Value Description
0
The corresponding interrupt is not active.
1
The corresponding interrupt is active, or active and pending.
July 03, 2014
141
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 13: Interrupt 32-54 Active Bit (ACTIVE1), offset 0x304
Note:
This register can only be accessed from privileged mode.
The ACTIVE1 register indicates which interrupts are active. Bit 0 corresponds to Interrupt 32; bit
22 corresponds to Interrupt 54. See Table 2-9 on page 106 for interrupt assignments.
Caution – Do not manually set or clear the bits in this register.
Interrupt 32-54 Active Bit (ACTIVE1)
Base 0xE000.E000
Offset 0x304
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
reserved
Type
Reset
19
18
17
16
INT
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
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
INT
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:23
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.
22:0
INT
RO
0x00.0000
Interrupt Active
Value Description
0
The corresponding interrupt is not active.
1
The corresponding interrupt is active, or active and pending.
142
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 14: Interrupt 0-3 Priority (PRI0), offset 0x400
Register 15: Interrupt 4-7 Priority (PRI1), offset 0x404
Register 16: Interrupt 8-11 Priority (PRI2), offset 0x408
Register 17: Interrupt 12-15 Priority (PRI3), offset 0x40C
Register 18: Interrupt 16-19 Priority (PRI4), offset 0x410
Register 19: Interrupt 20-23 Priority (PRI5), offset 0x414
Register 20: Interrupt 24-27 Priority (PRI6), offset 0x418
Register 21: Interrupt 28-31 Priority (PRI7), offset 0x41C
Register 22: Interrupt 32-35 Priority (PRI8), offset 0x420
Register 23: Interrupt 36-39 Priority (PRI9), offset 0x424
Register 24: Interrupt 40-43 Priority (PRI10), offset 0x428
Register 25: Interrupt 44-47 Priority (PRI11), offset 0x42C
Register 26: Interrupt 48-51 Priority (PRI12), offset 0x430
Register 27: Interrupt 52-54 Priority (PRI13), offset 0x434
Note:
This register can only be accessed from privileged mode.
The PRIn registers provide 3-bit priority fields for each interrupt. These registers are byte accessible.
Each register holds four priority fields that are assigned to interrupts as follows:
PRIn Register Bit Field
Interrupt
Bits 31:29
Interrupt [4n+3]
Bits 23:21
Interrupt [4n+2]
Bits 15:13
Interrupt [4n+1]
Bits 7:5
Interrupt [4n]
See Table 2-9 on page 106 for interrupt assignments.
Each priority level can be split into separate group priority and subpriority fields. The PRIGROUP
field in the Application Interrupt and Reset Control (APINT) register (see page 153) indicates the
position of the binary point that splits the priority and subpriority fields.
These registers can only be accessed from privileged mode.
July 03, 2014
143
Texas Instruments-Production Data
Cortex-M3 Peripherals
Interrupt 0-3 Priority (PRI0)
Base 0xE000.E000
Offset 0x400
Type R/W, reset 0x0000.0000
31
30
29
28
27
INTD
Type
Reset
25
24
23
reserved
22
21
20
19
INTC
18
17
16
reserved
R/W
0
R/W
0
R/W
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
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
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
RO
0
RO
0
RO
0
RO
0
INTB
Type
Reset
26
R/W
0
R/W
0
reserved
RO
0
INTA
Bit/Field
Name
Type
Reset
31:29
INTD
R/W
0x0
R/W
0
reserved
RO
0
Description
Interrupt Priority for Interrupt [4n+3]
This field holds a priority value, 0-7, for the interrupt with the number
[4n+3], where n is the number of the Interrupt Priority register (n=0 for
PRI0, and so on). The lower the value, the greater the priority of the
corresponding interrupt.
28:24
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.
23:21
INTC
R/W
0x0
Interrupt Priority for Interrupt [4n+2]
This field holds a priority value, 0-7, for the interrupt with the number
[4n+2], where n is the number of the Interrupt Priority register (n=0 for
PRI0, and so on). The lower the value, the greater the priority of the
corresponding interrupt.
20:16
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.
15:13
INTB
R/W
0x0
Interrupt Priority for Interrupt [4n+1]
This field holds a priority value, 0-7, for the interrupt with the number
[4n+1], where n is the number of the Interrupt Priority register (n=0 for
PRI0, and so on). The lower the value, the greater the priority of the
corresponding interrupt.
12:8
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.
7:5
INTA
R/W
0x0
Interrupt Priority for Interrupt [4n]
This field holds a priority value, 0-7, for the interrupt with the number
[4n], where n is the number of the Interrupt Priority register (n=0 for
PRI0, and so on). The lower the value, the greater the priority of the
corresponding interrupt.
4:0
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.
144
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 28: Software Trigger Interrupt (SWTRIG), offset 0xF00
Note:
Only privileged software can enable unprivileged access to the SWTRIG register.
Writing an interrupt number to the SWTRIG register generates a Software Generated Interrupt (SGI).
See Table 2-9 on page 106 for interrupt assignments.
When the MAINPEND bit in the Configuration and Control (CFGCTRL) register (see page 157) is
set, unprivileged software can access the SWTRIG register.
Software Trigger Interrupt (SWTRIG)
Base 0xE000.E000
Offset 0xF00
Type WO, reset 0x0000.0000
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
INTID
Bit/Field
Name
Type
Reset
31:6
reserved
RO
0x0000.00
5:0
INTID
WO
0x00
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Interrupt ID
This field holds the interrupt ID of the required SGI. For example, a value
of 0x3 generates an interrupt on IRQ3.
3.5
System Control Block (SCB) Register Descriptions
This section lists and describes the System Control Block (SCB) registers, in numerical order by
address offset. The SCB registers can only be accessed from privileged mode.
All registers must be accessed with aligned word accesses except for the FAULTSTAT and
SYSPRI1-SYSPRI3 registers, which can be accessed with byte or aligned halfword or word accesses.
The processor does not support unaligned accesses to system control block registers.
July 03, 2014
145
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 29: Auxiliary Control (ACTLR), offset 0x008
Note:
This register can only be accessed from privileged mode.
The ACTLR register provides disable bits for IT folding, write buffer use for accesses to the default
memory map, and interruption of multi-cycle instructions. By default, this register is set to provide
optimum performance from the Cortex-M3 processor and does not normally require modification.
Auxiliary Control (ACTLR)
Base 0xE000.E000
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
2
1
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
9
8
7
6
5
4
3
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
DISFOLD DISWBUF DISMCYC
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
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.
2
DISFOLD
R/W
0
Disable IT Folding
Value Description
0
No effect.
1
Disables IT folding.
In some situations, the processor can start executing the first instruction
in an IT block while it is still executing the IT instruction. This behavior
is called IT folding, and improves performance, However, IT folding can
cause jitter in looping. If a task must avoid jitter, set the DISFOLD bit
before executing the task, to disable IT folding.
1
DISWBUF
R/W
0
Disable Write Buffer
Value Description
0
No effect.
1
Disables write buffer use during default memory map accesses.
In this situation, all bus faults are precise bus faults but
performance is decreased because any store to memory must
complete before the processor can execute the next instruction.
Note:
This bit only affects write buffers implemented in the
Cortex-M3 processor.
146
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
0
DISMCYC
R/W
0
Description
Disable Interrupts of Multiple Cycle Instructions
Value Description
0
No effect.
1
Disables interruption of load multiple and store multiple
instructions. In this situation, the interrupt latency of the
processor is increased because any LDM or STM must complete
before the processor can stack the current state and enter the
interrupt handler.
July 03, 2014
147
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 30: CPU ID Base (CPUID), offset 0xD00
Note:
This register can only be accessed from privileged mode.
The CPUID register contains the ARM® Cortex™-M3 processor part number, version, and
implementation information.
CPU ID Base (CPUID)
Base 0xE000.E000
Offset 0xD00
Type RO, reset 0x412F.C230
31
30
29
28
27
26
25
24
23
22
IMP
Type
Reset
21
20
19
18
VAR
RO
0
RO
1
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
0
RO
1
RO
0
RO
1
RO
1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
PARTNO
Type
Reset
RO
1
RO
1
RO
0
RO
0
RO
0
RO
0
RO
1
17
16
RO
1
RO
1
1
0
RO
0
RO
0
CON
REV
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:24
IMP
RO
0x41
Implementer Code
RO
1
RO
1
RO
0
RO
0
Value Description
0x41 ARM
23:20
VAR
RO
0x2
Variant Number
Value Description
0x2
19:16
CON
RO
0xF
The rn value in the rnpn product revision identifier, for example,
the 2 in r2p0.
Constant
Value Description
0xF
15:4
PARTNO
RO
0xC23
Always reads as 0xF.
Part Number
Value Description
0xC23 Cortex-M3 processor.
3:0
REV
RO
0x0
Revision Number
Value Description
0x0
The pn value in the rnpn product revision identifier, for example,
the 0 in r2p0.
148
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 31: Interrupt Control and State (INTCTRL), offset 0xD04
Note:
This register can only be accessed from privileged mode.
The INCTRL register provides a set-pending bit for the NMI exception, and set-pending and
clear-pending bits for the PendSV and SysTick exceptions. In addition, bits in this register indicate
the exception number of the exception being processed, whether there are preempted active
exceptions, the exception number of the highest priority pending exception, and whether any interrupts
are pending.
When writing to INCTRL, the effect is unpredictable when writing a 1 to both the PENDSV and
UNPENDSV bits, or writing a 1 to both the PENDSTSET and PENDSTCLR bits.
Interrupt Control and State (INTCTRL)
Base 0xE000.E000
Offset 0xD04
Type R/W, reset 0x0000.0000
31
30
NMISET
Type
Reset
29
reserved
28
26
PENDSV UNPENDSV
25
PENDSTSET PENDSTCLR
24
reserved
23
22
21
ISRPRE ISRPEND
20
19
18
reserved
17
16
VECPEND
R/W
0
RO
0
RO
0
R/W
0
WO
0
R/W
0
WO
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
VECPEND
Type
Reset
27
RO
0
RETBASE
RO
0
reserved
RO
0
Bit/Field
Name
Type
Reset
31
NMISET
R/W
0
VECACT
RO
0
Description
NMI Set Pending
Value Description
0
On a read, indicates an NMI exception is not pending.
On a write, no effect.
1
On a read, indicates an NMI exception is pending.
On a write, changes the NMI exception state to pending.
Because NMI is the highest-priority exception, normally the processor
enters the NMI exception handler as soon as it registers the setting of
this bit, and clears this bit on entering the interrupt handler. A read of
this bit by the NMI exception handler returns 1 only if the NMI signal is
reasserted while the processor is executing that handler.
30:29
reserved
RO
0x0
28
PENDSV
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.
PendSV Set Pending
Value Description
0
On a read, indicates a PendSV exception is not pending.
On a write, no effect.
1
On a read, indicates a PendSV exception is pending.
On a write, changes the PendSV exception state to pending.
Setting this bit is the only way to set the PendSV exception state to
pending. This bit is cleared by writing a 1 to the UNPENDSV bit.
July 03, 2014
149
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
27
UNPENDSV
WO
0
Description
PendSV Clear Pending
Value Description
0
On a write, no effect.
1
On a write, removes the pending state from the PendSV
exception.
This bit is write only; on a register read, its value is unknown.
26
PENDSTSET
R/W
0
SysTick Set Pending
Value Description
0
On a read, indicates a SysTick exception is not pending.
On a write, no effect.
1
On a read, indicates a SysTick exception is pending.
On a write, changes the SysTick exception state to pending.
This bit is cleared by writing a 1 to the PENDSTCLR bit.
25
PENDSTCLR
WO
0
SysTick Clear Pending
Value Description
0
On a write, no effect.
1
On a write, removes the pending state from the SysTick
exception.
This bit is write only; on a register read, its value is unknown.
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
ISRPRE
RO
0
Debug Interrupt Handling
Value Description
0
The release from halt does not take an interrupt.
1
The release from halt takes an interrupt.
This bit is only meaningful in Debug mode and reads as zero when the
processor is not in Debug mode.
22
ISRPEND
RO
0
Interrupt Pending
Value Description
0
No interrupt is pending.
1
An interrupt is pending.
This bit provides status for all interrupts excluding NMI and Faults.
21:19
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.
150
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
18:12
VECPEND
RO
0x00
Interrupt Pending Vector Number
This field contains the exception number of the highest priority pending
enabled exception. The value indicated by this field includes the effect
of the BASEPRI and FAULTMASK registers, but not any effect of the
PRIMASK register.
Value
Description
0x00
No exceptions are pending
0x01
Reserved
0x02
NMI
0x03
Hard fault
0x04
Memory management fault
0x05
Bus fault
0x06
Usage fault
0x07-0x0A Reserved
0x0B
SVCall
0x0C
Reserved for Debug
0x0D
Reserved
0x0E
PendSV
0x0F
SysTick
0x10
Interrupt Vector 0
0x11
Interrupt Vector 1
...
...
0x46
Interrupt Vector 54
0x47-0x7F Reserved
11
RETBASE
RO
0
Return to Base
Value Description
0
There are preempted active exceptions to execute.
1
There are no active exceptions, or the currently executing
exception is the only active exception.
This bit provides status for all interrupts excluding NMI and Faults. This
bit only has meaning if the processor is currently executing an ISR (the
Interrupt Program Status (IPSR) register is non-zero).
10:7
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.
6:0
VECACT
RO
0x00
Interrupt Pending Vector Number
This field contains the active exception number. The exception numbers
can be found in the description for the VECPEND field. If this field is clear,
the processor is in Thread mode. This field contains the same value as
the ISRNUM field in the IPSR register.
Subtract 16 from this value to obtain the IRQ number required to index
into the Interrupt Set Enable (ENn), Interrupt Clear Enable (DISn),
Interrupt Set Pending (PENDn), Interrupt Clear Pending (UNPENDn),
and Interrupt Priority (PRIn) registers (see page 86).
July 03, 2014
151
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 32: Vector Table Offset (VTABLE), offset 0xD08
Note:
This register can only be accessed from privileged mode.
The VTABLE register indicates the offset of the vector table base address from memory address
0x0000.0000.
Vector Table Offset (VTABLE)
Base 0xE000.E000
Offset 0xD08
Type R/W, reset 0x0000.0000
31
30
reserved
Type
Reset
29
28
27
26
25
24
23
BASE
RO
0
RO
0
R/W
0
15
14
13
22
21
20
19
18
17
16
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
OFFSET
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
12
11
10
9
8
7
6
5
OFFSET
Type
Reset
R/W
0
R/W
0
R/W
0
R/W
0
reserved
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
31:30
reserved
RO
0x0
29
BASE
R/W
0
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.
Vector Table Base
Value Description
28:9
OFFSET
R/W
0x000.00
0
The vector table is in the code memory region.
1
The vector table is in the SRAM memory region.
Vector Table Offset
When configuring the OFFSET field, the offset must be aligned to the
number of exception entries in the vector table. Because there are 54
interrupts, the offset must be aligned on a 512-byte boundary.
8:0
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.
152
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 33: Application Interrupt and Reset Control (APINT), offset 0xD0C
Note:
This register can only be accessed from privileged mode.
The APINT register provides priority grouping control for the exception model, endian status for
data accesses, and reset control of the system. To write to this register, 0x05FA must be written to
the VECTKEY field, otherwise the write is ignored.
The PRIGROUP field indicates the position of the binary point that splits the INTx fields in the
Interrupt Priority (PRIx) registers into separate group priority and subpriority fields. Table
3-8 on page 153 shows how the PRIGROUP value controls this split. The bit numbers in the Group
Priority Field and Subpriority Field columns in the table refer to the bits in the INTA field. For the
INTB field, the corresponding bits are 15:13; for INTC, 23:21; and for INTD, 31:29.
Note:
Determining preemption of an exception uses only the group priority field.
Table 3-8. Interrupt Priority Levels
a
PRIGROUP Bit Field
Binary Point
Group Priority Field Subpriority Field
Group
Priorities
Subpriorities
0x0 - 0x4
bxxx.
[7:5]
None
8
1
0x5
bxx.y
[7:6]
[5]
4
2
0x6
bx.yy
[7]
[6:5]
2
4
0x7
b.yyy
None
[7:5]
1
8
a. INTx field showing the binary point. An x denotes a group priority field bit, and a y denotes a subpriority field bit.
Application Interrupt and Reset Control (APINT)
Base 0xE000.E000
Offset 0xD0C
Type R/W, reset 0xFA05.0000
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
1
R/W
0
R/W
1
5
4
3
2
1
0
VECTKEY
Type
Reset
R/W
1
R/W
1
R/W
1
R/W
1
R/W
1
R/W
0
15
14
13
12
11
10
reserved
ENDIANESS
Type
Reset
RO
0
RO
0
RO
0
RO
0
R/W
1
R/W
0
R/W
0
R/W
0
9
8
7
6
PRIGROUP
RO
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
31:16
VECTKEY
R/W
0xFA05
reserved
R/W
0
RO
0
RO
0
RO
0
SYSRESREQ VECTCLRACT VECTRESET
RO
0
RO
0
WO
0
WO
0
WO
0
Description
Register Key
This field is used to guard against accidental writes to this register.
0x05FA must be written to this field in order to change the bits in this
register. On a read, 0xFA05 is returned.
15
ENDIANESS
RO
0
Data Endianess
The Stellaris implementation uses only little-endian mode so this is
cleared to 0.
14:11
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.
July 03, 2014
153
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
10:8
PRIGROUP
R/W
0x0
Description
Interrupt Priority Grouping
This field determines the split of group priority from subpriority (see
Table 3-8 on page 153 for more information).
7:3
reserved
RO
0x0
2
SYSRESREQ
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.
System Reset Request
Value Description
0
No effect.
1
Resets the core and all on-chip peripherals except the Debug
interface.
This bit is automatically cleared during the reset of the core and reads
as 0.
1
VECTCLRACT
WO
0
Clear Active NMI / Fault
This bit is reserved for Debug use and reads as 0. This bit must be
written as a 0, otherwise behavior is unpredictable.
0
VECTRESET
WO
0
System Reset
This bit is reserved for Debug use and reads as 0. This bit must be
written as a 0, otherwise behavior is unpredictable.
154
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 34: System Control (SYSCTRL), offset 0xD10
Note:
This register can only be accessed from privileged mode.
The SYSCTRL register controls features of entry to and exit from low-power state.
System Control (SYSCTRL)
Base 0xE000.E000
Offset 0xD10
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
2
1
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
10
9
8
7
6
5
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:5
reserved
RO
0x0000.00
4
SEVONPEND
R/W
0
RO
0
RO
0
RO
0
RO
0
4
3
SEVONPEND
reserved
R/W
0
RO
0
SLEEPDEEP SLEEPEXIT
R/W
0
R/W
0
0
reserved
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Wake Up on Pending
Value Description
0
Only enabled interrupts or events can wake up the processor;
disabled interrupts are excluded.
1
Enabled events and all interrupts, including disabled interrupts,
can wake up the processor.
When an event or interrupt enters the pending state, the event signal
wakes up the processor from WFE. If the processor is not waiting for an
event, the event is registered and affects the next WFE.
The processor also wakes up on execution of a SEV instruction or an
external event.
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
SLEEPDEEP
R/W
0
Deep Sleep Enable
Value Description
0
Use Sleep mode as the low power mode.
1
Use Deep-sleep mode as the low power mode.
July 03, 2014
155
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
1
SLEEPEXIT
R/W
0
Description
Sleep on ISR Exit
Value Description
0
When returning from Handler mode to Thread mode, do not
sleep when returning to Thread mode.
1
When returning from Handler mode to Thread mode, enter sleep
or deep sleep on return from an ISR.
Setting this bit enables an interrupt-driven application to avoid returning
to an empty main application.
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.
156
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 35: Configuration and Control (CFGCTRL), offset 0xD14
Note:
This register can only be accessed from privileged mode.
The CFGCTRL register controls entry to Thread mode and enables: the handlers for NMI, hard fault
and faults escalated by the FAULTMASK register to ignore bus faults; trapping of divide by zero
and unaligned accesses; and access to the SWTRIG register by unprivileged software (see page 145).
Configuration and Control (CFGCTRL)
Base 0xE000.E000
Offset 0xD14
Type R/W, reset 0x0000.0200
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
2
1
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
9
8
7
reserved
STKALIGN BFHFNMIGN
RO
0
RO
0
R/W
1
Bit/Field
Name
Type
Reset
31:10
reserved
RO
0x0000.00
9
STKALIGN
R/W
1
R/W
0
RO
0
RO
0
RO
0
4
3
DIV0
UNALIGNED
R/W
0
R/W
0
reserved MAINPEND BASETHR
RO
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.
Stack Alignment on Exception Entry
Value Description
0
The stack is 4-byte aligned.
1
The stack is 8-byte aligned.
On exception entry, the processor uses bit 9 of the stacked PSR to
indicate the stack alignment. On return from the exception, it uses this
stacked bit to restore the correct stack alignment.
8
BFHFNMIGN
R/W
0
Ignore Bus Fault in NMI and Fault
This bit enables handlers with priority -1 or -2 to ignore data bus faults
caused by load and store instructions. The setting of this bit applies to
the hard fault, NMI, and FAULTMASK escalated handlers.
Value Description
0
Data bus faults caused by load and store instructions cause a
lock-up.
1
Handlers running at priority -1 and -2 ignore data bus faults
caused by load and store instructions.
Set this bit only when the handler and its data are in absolutely safe
memory. The normal use of this bit is to probe system devices and
bridges to detect control path problems and fix them.
7:5
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.
July 03, 2014
157
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
4
DIV0
R/W
0
Description
Trap on Divide by 0
This bit enables faulting or halting when the processor executes an
SDIV or UDIV instruction with a divisor of 0.
Value Description
3
UNALIGNED
R/W
0
0
Do not trap on divide by 0. A divide by zero returns a quotient
of 0.
1
Trap on divide by 0.
Trap on Unaligned Access
Value Description
0
Do not trap on unaligned halfword and word accesses.
1
Trap on unaligned halfword and word accesses. An unaligned
access generates a usage fault.
Unaligned LDM, STM, LDRD, and STRD instructions always fault
regardless of whether UNALIGNED is set.
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
MAINPEND
R/W
0
Allow Main Interrupt Trigger
Value Description
0
BASETHR
R/W
0
0
Disables unprivileged software access to the SWTRIG register.
1
Enables unprivileged software access to the SWTRIG register
(see page 145).
Thread State Control
Value Description
0
The processor can enter Thread mode only when no exception
is active.
1
The processor can enter Thread mode from any level under the
control of an EXC_RETURN value (see “Exception
Return” on page 110 for more information).
158
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 36: System Handler Priority 1 (SYSPRI1), offset 0xD18
Note:
This register can only be accessed from privileged mode.
The SYSPRI1 register configures the priority level, 0 to 7 of the usage fault, bus fault, and memory
management fault exception handlers. This register is byte-accessible.
System Handler Priority 1 (SYSPRI1)
Base 0xE000.E000
Offset 0xD18
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
14
13
12
11
15
BUS
Type
Reset
R/W
0
R/W
0
RO
0
RO
0
RO
0
R/W
0
10
9
8
7
reserved
R/W
0
RO
0
22
21
20
19
USAGE
RO
0
RO
0
R/W
0
R/W
0
RO
0
RO
0
6
5
4
3
MEM
RO
0
RO
0
R/W
0
R/W
0
18
17
16
RO
0
RO
0
RO
0
2
1
0
RO
0
RO
0
reserved
reserved
R/W
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:24
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
23:21
USAGE
R/W
0x0
Usage Fault Priority
This field configures the priority level of the usage fault. Configurable
priority values are in the range 0-7, with lower values having higher
priority.
20:16
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.
15:13
BUS
R/W
0x0
Bus Fault Priority
This field configures the priority level of the bus fault. Configurable priority
values are in the range 0-7, with lower values having higher priority.
12:8
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.
7:5
MEM
R/W
0x0
Memory Management Fault Priority
This field configures the priority level of the memory management fault.
Configurable priority values are in the range 0-7, with lower values
having higher priority.
4:0
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.
July 03, 2014
159
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 37: System Handler Priority 2 (SYSPRI2), offset 0xD1C
Note:
This register can only be accessed from privileged mode.
The SYSPRI2 register configures the priority level, 0 to 7 of the SVCall handler. This register is
byte-accessible.
System Handler Priority 2 (SYSPRI2)
Base 0xE000.E000
Offset 0xD1C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
SVC
Type
Reset
22
21
20
19
18
17
16
reserved
R/W
0
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
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
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:29
SVC
R/W
0x0
RO
0
Description
SVCall Priority
This field configures the priority level of SVCall. Configurable priority
values are in the range 0-7, with lower values having higher priority.
28:0
reserved
RO
0x000.0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
160
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 38: System Handler Priority 3 (SYSPRI3), offset 0xD20
Note:
This register can only be accessed from privileged mode.
The SYSPRI3 register configures the priority level, 0 to 7 of the SysTick exception and PendSV
handlers. This register is byte-accessible.
System Handler Priority 3 (SYSPRI3)
Base 0xE000.E000
Offset 0xD20
Type R/W, reset 0x0000.0000
31
30
29
28
27
TICK
Type
Reset
26
25
24
23
reserved
R/W
0
R/W
0
R/W
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
15
14
13
12
11
10
9
8
7
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
22
21
20
19
PENDSV
R/W
0
R/W
0
RO
0
RO
0
6
5
4
3
DEBUG
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:29
TICK
R/W
0x0
RO
0
R/W
0
R/W
0
18
17
16
RO
0
RO
0
RO
0
2
1
0
RO
0
RO
0
reserved
reserved
R/W
0
RO
0
RO
0
RO
0
Description
SysTick Exception Priority
This field configures the priority level of the SysTick exception.
Configurable priority values are in the range 0-7, with lower values
having higher priority.
28:24
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.
23:21
PENDSV
R/W
0x0
PendSV Priority
This field configures the priority level of PendSV. Configurable priority
values are in the range 0-7, with lower values having higher priority.
20:8
reserved
RO
0x000
7:5
DEBUG
R/W
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.
Debug Priority
This field configures the priority level of Debug. Configurable priority
values are in the range 0-7, with lower values having higher priority.
4:0
reserved
RO
0x0.0000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
July 03, 2014
161
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 39: System Handler Control and State (SYSHNDCTRL), offset 0xD24
Note:
This register can only be accessed from privileged mode.
The SYSHNDCTRL register enables the system handlers, and indicates the pending status of the
usage fault, bus fault, memory management fault, and SVC exceptions as well as the active status
of the system handlers.
If a system handler is disabled and the corresponding fault occurs, the processor treats the fault as
a hard fault.
This register can be modified to change the pending or active status of system exceptions. An OS
kernel can write to the active bits to perform a context switch that changes the current exception
type.
Caution – Software that changes the value of an active bit in this register without correct adjustment
to the stacked content can cause the processor to generate a fault exception. Ensure software that writes
to this register retains and subsequently restores the current active status.
If the value of a bit in this register must be modified after enabling the system handlers, a
read-modify-write procedure must be used to ensure that only the required bit is modified.
System Handler Control and State (SYSHNDCTRL)
Base 0xE000.E000
Offset 0xD24
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
SVC
BUSP
MEMP
USAGEP
R/W
0
R/W
0
R/W
0
R/W
0
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
USAGE
BUS
MEM
R/W
0
R/W
0
R/W
0
10
9
8
7
6
5
4
3
2
1
0
TICK
PNDSV
reserved
MON
SVCA
R/W
0
R/W
0
RO
0
R/W
0
R/W
0
USGA
reserved
BUSA
MEMA
R/W
0
RO
0
R/W
0
R/W
0
reserved
Type
Reset
Type
Reset
reserved
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:19
reserved
RO
0x000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
18
USAGE
R/W
0
Usage Fault Enable
Value Description
17
BUS
R/W
0
0
Disables the usage fault exception.
1
Enables the usage fault exception.
Bus Fault Enable
Value Description
0
Disables the bus fault exception.
1
Enables the bus fault exception.
162
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
16
MEM
R/W
0
Description
Memory Management Fault Enable
Value Description
15
SVC
R/W
0
0
Disables the memory management fault exception.
1
Enables the memory management fault exception.
SVC Call Pending
Value Description
0
An SVC call exception is not pending.
1
An SVC call exception is pending.
This bit can be modified to change the pending status of the SVC call
exception.
14
BUSP
R/W
0
Bus Fault Pending
Value Description
0
A bus fault exception is not pending.
1
A bus fault exception is pending.
This bit can be modified to change the pending status of the bus fault
exception.
13
MEMP
R/W
0
Memory Management Fault Pending
Value Description
0
A memory management fault exception is not pending.
1
A memory management fault exception is pending.
This bit can be modified to change the pending status of the memory
management fault exception.
12
USAGEP
R/W
0
Usage Fault Pending
Value Description
0
A usage fault exception is not pending.
1
A usage fault exception is pending.
This bit can be modified to change the pending status of the usage fault
exception.
11
TICK
R/W
0
SysTick Exception Active
Value Description
0
A SysTick exception is not active.
1
A SysTick exception is active.
This bit can be modified to change the active status of the SysTick
exception, however, see the Caution above before setting this bit.
July 03, 2014
163
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
10
PNDSV
R/W
0
Description
PendSV Exception Active
Value Description
0
A PendSV exception is not active.
1
A PendSV exception is active.
This bit can be modified to change the active status of the PendSV
exception, however, see the Caution above before setting this bit.
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
MON
R/W
0
Debug Monitor Active
Value Description
7
SVCA
R/W
0
0
The Debug monitor is not active.
1
The Debug monitor is active.
SVC Call Active
Value Description
0
SVC call is not active.
1
SVC call is active.
This bit can be modified to change the active status of the SVC call
exception, however, see the Caution above before setting this bit.
6:4
reserved
RO
0x0
3
USGA
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.
Usage Fault Active
Value Description
0
Usage fault is not active.
1
Usage fault is active.
This bit can be modified to change the active status of the usage fault
exception, however, see the Caution above before setting this bit.
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
BUSA
R/W
0
Bus Fault Active
Value Description
0
Bus fault is not active.
1
Bus fault is active.
This bit can be modified to change the active status of the bus fault
exception, however, see the Caution above before setting this bit.
164
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
0
MEMA
R/W
0
Description
Memory Management Fault Active
Value Description
0
Memory management fault is not active.
1
Memory management fault is active.
This bit can be modified to change the active status of the memory
management fault exception, however, see the Caution above before
setting this bit.
July 03, 2014
165
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 40: Configurable Fault Status (FAULTSTAT), offset 0xD28
Note:
This register can only be accessed from privileged mode.
The FAULTSTAT register indicates the cause of a memory management fault, bus fault, or usage
fault. Each of these functions is assigned to a subregister as follows:
■ Usage Fault Status (UFAULTSTAT), bits 31:16
■ Bus Fault Status (BFAULTSTAT), bits 15:8
■ Memory Management Fault Status (MFAULTSTAT), bits 7:0
FAULTSTAT is byte accessible. FAULTSTAT or its subregisters can be accessed as follows:
■
■
■
■
■
The complete FAULTSTAT register, with a word access to offset 0xD28
The MFAULTSTAT, with a byte access to offset 0xD28
The MFAULTSTAT and BFAULTSTAT, with a halfword access to offset 0xD28
The BFAULTSTAT, with a byte access to offset 0xD29
The UFAULTSTAT, with a halfword access to offset 0xD2A
Bits are cleared by writing a 1 to them.
In a fault handler, the true faulting address can be determined by:
1. Read and save the Memory Management Fault Address (MMADDR) or Bus Fault Address
(FAULTADDR) value.
2. Read the MMARV bit in MFAULTSTAT, or the BFARV bit in BFAULTSTAT to determine if the
MMADDR or FAULTADDR contents are valid.
Software must follow this sequence because another higher priority exception might change the
MMADDR or FAULTADDR value. For example, if a higher priority handler preempts the current
fault handler, the other fault might change the MMADDR or FAULTADDR value.
Configurable Fault Status (FAULTSTAT)
Base 0xE000.E000
Offset 0xD28
Type R/W1C, reset 0x0000.0000
31
30
29
28
27
26
reserved
Type
Reset
RO
0
RO
0
RO
0
15
14
13
BFARV
Type
Reset
R/W1C
0
reserved
RO
0
RO
0
RO
0
RO
0
RO
0
25
24
DIV0
UNALIGN
R/W1C
0
R/W1C
0
23
22
21
20
reserved
RO
0
RO
0
RO
0
6
5
12
11
10
9
8
7
BSTKE
BUSTKE
IMPRE
PRECISE
IBUS
MMARV
R/W1C
0
R/W1C
0
R/W1C
0
R/W1C
0
R/W1C
0
R/W1C
0
reserved
RO
0
RO
0
RO
0
4
MSTKE
R/W1C
0
19
18
17
16
NOCP
INVPC
INVSTAT
UNDEF
R/W1C
0
R/W1C
0
R/W1C
0
R/W1C
0
3
2
MUSTKE reserved
R/W1C
0
RO
0
1
0
DERR
IERR
R/W1C
0
R/W1C
0
Bit/Field
Name
Type
Reset
Description
31:26
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.
166
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
25
DIV0
R/W1C
0
Description
Divide-by-Zero Usage Fault
Value Description
0
No divide-by-zero fault has occurred, or divide-by-zero trapping
is not enabled.
1
The processor has executed an SDIV or UDIV instruction with
a divisor of 0.
When this bit is set, the PC value stacked for the exception return points
to the instruction that performed the divide by zero.
Trapping on divide-by-zero is enabled by setting the DIV0 bit in the
Configuration and Control (CFGCTRL) register (see page 157).
This bit is cleared by writing a 1 to it.
24
UNALIGN
R/W1C
0
Unaligned Access Usage Fault
Value Description
0
No unaligned access fault has occurred, or unaligned access
trapping is not enabled.
1
The processor has made an unaligned memory access.
Unaligned LDM, STM, LDRD, and STRD instructions always fault
regardless of the configuration of this bit.
Trapping on unaligned access is enabled by setting the UNALIGNED bit
in the CFGCTRL register (see page 157).
This bit is cleared by writing a 1 to it.
23:20
reserved
RO
0x00
19
NOCP
R/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.
No Coprocessor Usage Fault
Value Description
0
A usage fault has not been caused by attempting to access a
coprocessor.
1
The processor has attempted to access a coprocessor.
This bit is cleared by writing a 1 to it.
18
INVPC
R/W1C
0
Invalid PC Load Usage Fault
Value Description
0
A usage fault has not been caused by attempting to load an
invalid PC value.
1
The processor has attempted an illegal load of EXC_RETURN
to the PC as a result of an invalid context or an invalid
EXC_RETURN value.
When this bit is set, the PC value stacked for the exception return points
to the instruction that tried to perform the illegal load of the PC.
This bit is cleared by writing a 1 to it.
July 03, 2014
167
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
17
INVSTAT
R/W1C
0
Description
Invalid State Usage Fault
Value Description
0
A usage fault has not been caused by an invalid state.
1
The processor has attempted to execute an instruction that
makes illegal use of the EPSR register.
When this bit is set, the PC value stacked for the exception return points
to the instruction that attempted the illegal use of the Execution
Program Status Register (EPSR) register.
This bit is not set if an undefined instruction uses the EPSR register.
This bit is cleared by writing a 1 to it.
16
UNDEF
R/W1C
0
Undefined Instruction Usage Fault
Value Description
0
A usage fault has not been caused by an undefined instruction.
1
The processor has attempted to execute an undefined
instruction.
When this bit is set, the PC value stacked for the exception return points
to the undefined instruction.
An undefined instruction is an instruction that the processor cannot
decode.
This bit is cleared by writing a 1 to it.
15
BFARV
R/W1C
0
Bus Fault Address Register Valid
Value Description
0
The value in the Bus Fault Address (FAULTADDR) register
is not a valid fault address.
1
The FAULTADDR register is holding a valid fault address.
This bit is set after a bus fault, where the address is known. Other faults
can clear this bit, such as a memory management fault occurring later.
If a bus fault occurs and is escalated to a hard fault because of priority,
the hard fault handler must clear this bit. This action prevents problems
if returning to a stacked active bus fault handler whose FAULTADDR
register value has been overwritten.
This bit is cleared by writing a 1 to it.
14:13
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.
168
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
12
BSTKE
R/W1C
0
Description
Stack Bus Fault
Value Description
0
No bus fault has occurred on stacking for exception entry.
1
Stacking for an exception entry has caused one or more bus
faults.
When this bit is set, the SP is still adjusted but the values in the context
area on the stack might be incorrect. A fault address is not written to
the FAULTADDR register.
This bit is cleared by writing a 1 to it.
11
BUSTKE
R/W1C
0
Unstack Bus Fault
Value Description
0
No bus fault has occurred on unstacking for a return from
exception.
1
Unstacking for a return from exception has caused one or more
bus faults.
This fault is chained to the handler. Thus, when this bit is set, the original
return stack is still present. The SP is not adjusted from the failing return,
a new save is not performed, and a fault address is not written to the
FAULTADDR register.
This bit is cleared by writing a 1 to it.
10
IMPRE
R/W1C
0
Imprecise Data Bus Error
Value Description
0
An imprecise data bus error has not occurred.
1
A data bus error has occurred, but the return address in the
stack frame is not related to the instruction that caused the error.
When this bit is set, a fault address is not written to the FAULTADDR
register.
This fault is asynchronous. Therefore, if the fault is detected when the
priority of the current process is higher than the bus fault priority, the
bus fault becomes pending and becomes active only when the processor
returns from all higher-priority processes. If a precise fault occurs before
the processor enters the handler for the imprecise bus fault, the handler
detects that both the IMPRE bit is set and one of the precise fault status
bits is set.
This bit is cleared by writing a 1 to it.
9
PRECISE
R/W1C
0
Precise Data Bus Error
Value Description
0
A precise data bus error has not occurred.
1
A data bus error has occurred, and the PC value stacked for
the exception return points to the instruction that caused the
fault.
When this bit is set, the fault address is written to the FAULTADDR
register.
This bit is cleared by writing a 1 to it.
July 03, 2014
169
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
8
IBUS
R/W1C
0
Description
Instruction Bus Error
Value Description
0
An instruction bus error has not occurred.
1
An instruction bus error has occurred.
The processor detects the instruction bus error on prefetching an
instruction, but sets this bit only if it attempts to issue the faulting
instruction.
When this bit is set, a fault address is not written to the FAULTADDR
register.
This bit is cleared by writing a 1 to it.
7
MMARV
R/W1C
0
Memory Management Fault Address Register Valid
Value Description
0
The value in the Memory Management Fault Address
(MMADDR) register is not a valid fault address.
1
The MMADDR register is holding a valid fault address.
If a memory management fault occurs and is escalated to a hard fault
because of priority, the hard fault handler must clear this bit. This action
prevents problems if returning to a stacked active memory management
fault handler whose MMADDR register value has been overwritten.
This bit is cleared by writing a 1 to it.
6:5
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
MSTKE
R/W1C
0
Stack Access Violation
Value Description
0
No memory management fault has occurred on stacking for
exception entry.
1
Stacking for an exception entry has caused one or more access
violations.
When this bit is set, the SP is still adjusted but the values in the context
area on the stack might be incorrect. A fault address is not written to
the MMADDR register.
This bit is cleared by writing a 1 to it.
170
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
3
MUSTKE
R/W1C
0
Description
Unstack Access Violation
Value Description
0
No memory management fault has occurred on unstacking for
a return from exception.
1
Unstacking for a return from exception has caused one or more
access violations.
This fault is chained to the handler. Thus, when this bit is set, the original
return stack is still present. The SP is not adjusted from the failing return,
a new save is not performed, and a fault address is not written to the
MMADDR register.
This bit is cleared by writing a 1 to it.
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
DERR
R/W1C
0
Data Access Violation
Value Description
0
A data access violation has not occurred.
1
The processor attempted a load or store at a location that does
not permit the operation.
When this bit is set, the PC value stacked for the exception return points
to the faulting instruction and the address of the attempted access is
written to the MMADDR register.
This bit is cleared by writing a 1 to it.
0
IERR
R/W1C
0
Instruction Access Violation
Value Description
0
An instruction access violation has not occurred.
1
The processor attempted an instruction fetch from a location
that does not permit execution.
This fault occurs on any access to an XN region, even when the MPU
is disabled or not present.
When this bit is set, the PC value stacked for the exception return points
to the faulting instruction and the address of the attempted access is
not written to the MMADDR register.
This bit is cleared by writing a 1 to it.
July 03, 2014
171
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 41: Hard Fault Status (HFAULTSTAT), offset 0xD2C
Note:
This register can only be accessed from privileged mode.
The HFAULTSTAT register gives information about events that activate the hard fault handler.
Bits are cleared by writing a 1 to them.
Hard Fault Status (HFAULTSTAT)
Base 0xE000.E000
Offset 0xD2C
Type R/W1C, reset 0x0000.0000
Type
Reset
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
DBG
FORCED
R/W1C
0
R/W1C
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
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
VECT
reserved
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
R/W1C
0
RO
0
reserved
Type
Reset
Bit/Field
Name
Type
Reset
31
DBG
R/W1C
0
Description
Debug Event
This bit is reserved for Debug use. This bit must be written as a 0,
otherwise behavior is unpredictable.
30
FORCED
R/W1C
0
Forced Hard Fault
Value Description
0
No forced hard fault has occurred.
1
A forced hard fault has been generated by escalation of a fault
with configurable priority that cannot be handled, either because
of priority or because it is disabled.
When this bit is set, the hard fault handler must read the other fault
status registers to find the cause of the fault.
This bit is cleared by writing a 1 to it.
29:2
reserved
RO
0x00
1
VECT
R/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.
Vector Table Read Fault
Value Description
0
No bus fault has occurred on a vector table read.
1
A bus fault occurred on a vector table read.
This error is always handled by the hard fault handler.
When this bit is set, the PC value stacked for the exception return points
to the instruction that was preempted by the exception.
This bit is cleared by writing a 1 to it.
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.
172
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 42: Memory Management Fault Address (MMADDR), offset 0xD34
Note:
This register can only be accessed from privileged mode.
The MMADDR register contains the address of the location that generated a memory management
fault. When an unaligned access faults, the address in the MMADDR register is the actual address
that faulted. Because a single read or write instruction can be split into multiple aligned accesses,
the fault address can be any address in the range of the requested access size. Bits in the Memory
Management Fault Status (MFAULTSTAT) register indicate the cause of the fault and whether
the value in the MMADDR register is valid (see page 166).
Memory Management Fault Address (MMADDR)
Base 0xE000.E000
Offset 0xD34
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
7
6
5
4
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
ADDR
Type
Reset
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
ADDR
Type
Reset
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
Bit/Field
Name
Type
Reset
31:0
ADDR
R/W
-
R/W
-
Description
Fault Address
When the MMARV bit of MFAULTSTAT is set, this field holds the address
of the location that generated the memory management fault.
July 03, 2014
173
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 43: Bus Fault Address (FAULTADDR), offset 0xD38
Note:
This register can only be accessed from privileged mode.
The FAULTADDR register contains the address of the location that generated a bus fault. When
an unaligned access faults, the address in the FAULTADDR register is the one requested by the
instruction, even if it is not the address of the fault. Bits in the Bus Fault Status (BFAULTSTAT)
register indicate the cause of the fault and whether the value in the FAULTADDR register is valid
(see page 166).
Bus Fault Address (FAULTADDR)
Base 0xE000.E000
Offset 0xD38
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
7
6
5
4
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
ADDR
Type
Reset
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
ADDR
Type
Reset
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
Bit/Field
Name
Type
Reset
31:0
ADDR
R/W
-
R/W
-
Description
Fault Address
When the FAULTADDRV bit of BFAULTSTAT is set, this field holds the
address of the location that generated the bus fault.
3.6
Memory Protection Unit (MPU) Register Descriptions
This section lists and describes the Memory Protection Unit (MPU) registers, in numerical order by
address offset.
The MPU registers can only be accessed from privileged mode.
174
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 44: MPU Type (MPUTYPE), offset 0xD90
Note:
This register can only be accessed from privileged mode.
The MPUTYPE register indicates whether the MPU is present, and if so, how many regions it
supports.
MPU Type (MPUTYPE)
Base 0xE000.E000
Offset 0xD90
Type RO, reset 0x0000.0800
31
30
29
28
27
26
25
24
23
22
21
20
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
DREGION
Type
Reset
RO
0
RO
0
RO
0
RO
0
19
18
17
16
RO
0
IREGION
RO
0
RO
0
RO
0
RO
0
4
3
2
1
reserved
RO
1
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
0
SEPARATE
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:24
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
23:16
IREGION
RO
0x00
Number of I Regions
This field indicates the number of supported MPU instruction regions.
This field always contains 0x00. The MPU memory map is unified and
is described by the DREGION field.
15:8
DREGION
RO
0x08
Number of D Regions
Value Description
0x08 Indicates there are eight supported MPU data regions.
7:1
reserved
RO
0x00
0
SEPARATE
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Separate or Unified MPU
Value Description
0
Indicates the MPU is unified.
July 03, 2014
175
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 45: MPU Control (MPUCTRL), offset 0xD94
Note:
This register can only be accessed from privileged mode.
The MPUCTRL register enables the MPU, enables the default memory map background region,
and enables use of the MPU when in the hard fault, Non-maskable Interrupt (NMI), and Fault Mask
Register (FAULTMASK) escalated handlers.
When the ENABLE and PRIVDEFEN bits are both set:
■ For privileged accesses, the default memory map is as described in “Memory Model” on page 94.
Any access by privileged software that does not address an enabled memory region behaves
as defined by the default memory map.
■ Any access by unprivileged software that does not address an enabled memory region causes
a memory management fault.
Execute Never (XN) and Strongly Ordered rules always apply to the System Control Space regardless
of the value of the ENABLE bit.
When the ENABLE bit is set, at least one region of the memory map must be enabled for the system
to function unless the PRIVDEFEN bit is set. If the PRIVDEFEN bit is set and no regions are enabled,
then only privileged software can operate.
When the ENABLE bit is clear, the system uses the default memory map, which has the same
memory attributes as if the MPU is not implemented (see Table 2-5 on page 97 for more information).
The default memory map applies to accesses from both privileged and unprivileged software.
When the MPU is enabled, accesses to the System Control Space and vector table are always
permitted. Other areas are accessible based on regions and whether PRIVDEFEN is set.
Unless HFNMIENA is set, the MPU is not enabled when the processor is executing the handler for
an exception with priority –1 or –2. These priorities are only possible when handling a hard fault or
NMI exception or when FAULTMASK is enabled. Setting the HFNMIENA bit enables the MPU when
operating with these two priorities.
MPU Control (MPUCTRL)
Base 0xE000.E000
Offset 0xD94
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
reserved
Type
Reset
reserved
Type
Reset
RO
0
Bit/Field
Name
Type
Reset
31:3
reserved
RO
0x0000.000
PRIVDEFEN HFNMIENA
R/W
0
R/W
0
ENABLE
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.
176
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
2
PRIVDEFEN
R/W
0
Description
MPU Default Region
This bit enables privileged software access to the default memory map.
Value Description
0
If the MPU is enabled, this bit disables use of the default memory
map. Any memory access to a location not covered by any
enabled region causes a fault.
1
If the MPU is enabled, this bit enables use of the default memory
map as a background region for privileged software accesses.
When this bit is set, the background region acts as if it is region number
-1. Any region that is defined and enabled has priority over this default
map.
If the MPU is disabled, the processor ignores this bit.
1
HFNMIENA
R/W
0
MPU Enabled During Faults
This bit controls the operation of the MPU during hard fault, NMI, and
FAULTMASK handlers.
Value Description
0
The MPU is disabled during hard fault, NMI, and FAULTMASK
handlers, regardless of the value of the ENABLE bit.
1
The MPU is enabled during hard fault, NMI, and FAULTMASK
handlers.
When the MPU is disabled and this bit is set, the resulting behavior is
unpredictable.
0
ENABLE
R/W
0
MPU Enable
Value Description
0
The MPU is disabled.
1
The MPU is enabled.
When the MPU is disabled and the HFNMIENA bit is set, the resulting
behavior is unpredictable.
July 03, 2014
177
Texas Instruments-Production Data
Cortex-M3 Peripherals
Register 46: MPU Region Number (MPUNUMBER), offset 0xD98
Note:
This register can only be accessed from privileged mode.
The MPUNUMBER register selects which memory region is referenced by the MPU Region Base
Address (MPUBASE) and MPU Region Attribute and Size (MPUATTR) registers. Normally, the
required region number should be written to this register before accessing the MPUBASE or the
MPUATTR register. However, the region number can be changed by writing to the MPUBASE
register with the VALID bit set (see page 179). This write updates the value of the REGION field.
MPU Region Number (MPUNUMBER)
Base 0xE000.E000
Offset 0xD98
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
Bit/Field
Name
Type
Reset
31:3
reserved
RO
0x0000.000
2:0
NUMBER
R/W
0x0
NUMBER
RO
0
RO
0
RO
0
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.
MPU Region to Access
This field indicates the MPU region referenced by the MPUBASE and
MPUATTR registers. The MPU supports eight memory regions.
178
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 47: MPU Region Base Address (MPUBASE), offset 0xD9C
Register 48: MPU Region Base Address Alias 1 (MPUBASE1), offset 0xDA4
Register 49: MPU Region Base Address Alias 2 (MPUBASE2), offset 0xDAC
Register 50: MPU Region Base Address Alias 3 (MPUBASE3), offset 0xDB4
Note:
This register can only be accessed from privileged mode.
The MPUBASE register defines the base address of the MPU region selected by the MPU Region
Number (MPUNUMBER) register and can update the value of the MPUNUMBER register. To
change the current region number and update the MPUNUMBER register, write the MPUBASE
register with the VALID bit set.
The ADDR field is bits 31:N of the MPUBASE register. Bits (N-1):5 are reserved. The region size,
as specified by the SIZE field in the MPU Region Attribute and Size (MPUATTR) register, defines
the value of N where:
N = Log2(Region size in bytes)
If the region size is configured to 4 GB in the MPUATTR register, there is no valid ADDR field. In
this case, the region occupies the complete memory map, and the base address is 0x0000.0000.
The base address is aligned to the size of the region. For example, a 64-KB region must be aligned
on a multiple of 64 KB, for example, at 0x0001.0000 or 0x0002.0000.
MPU Region Base Address (MPUBASE)
Base 0xE000.E000
Offset 0xD9C
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
VALID
reserved
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
WO
0
RO
0
ADDR
Type
Reset
ADDR
Type
Reset
R/W
0
Bit/Field
Name
Type
Reset
31:5
ADDR
R/W
0x0000.000
REGION
R/W
0
R/W
0
R/W
0
Description
Base Address Mask
Bits 31:N in this field contain the region base address. The value of N
depends on the region size, as shown above. The remaining bits (N-1):5
are 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.
July 03, 2014
179
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
4
VALID
WO
0
Description
Region Number Valid
Value Description
0
The MPUNUMBER register is not changed and the processor
updates the base address for the region specified in the
MPUNUMBER register and ignores the value of the REGION
field.
1
The MPUNUMBER register is updated with the value of the
REGION field and the base address is updated for the region
specified in the REGION field.
This bit is always read as 0.
3
reserved
RO
0
2:0
REGION
R/W
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.
Region Number
On a write, contains the value to be written to the MPUNUMBER register.
On a read, returns the current region number in the MPUNUMBER
register.
180
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 51: MPU Region Attribute and Size (MPUATTR), offset 0xDA0
Register 52: MPU Region Attribute and Size Alias 1 (MPUATTR1), offset 0xDA8
Register 53: MPU Region Attribute and Size Alias 2 (MPUATTR2), offset 0xDB0
Register 54: MPU Region Attribute and Size Alias 3 (MPUATTR3), offset 0xDB8
Note:
This register can only be accessed from privileged mode.
The MPUATTR register defines the region size and memory attributes of the MPU region specified
by the MPU Region Number (MPUNUMBER) register and enables that region and any subregions.
The MPUATTR register is accessible using word or halfword accesses with the most-significant
halfword holding the region attributes and the least-significant halfword holds the region size and
the region and subregion enable bits.
The MPU access permission attribute bits, XN, AP, TEX, S, C, and B, control access to the
corresponding memory region. If an access is made to an area of memory without the required
permissions, then the MPU generates a permission fault.
The SIZE field defines the size of the MPU memory region specified by the MPUNUMBER register
as follows:
(Region size in bytes) = 2(SIZE+1)
The smallest permitted region size is 32 bytes, corresponding to a SIZE value of 4. Table
3-9 on page 181 gives example SIZE values with the corresponding region size and value of N in
the MPU Region Base Address (MPUBASE) register.
Table 3-9. Example SIZE Field Values
a
SIZE Encoding
Region Size
Value of N
Note
00100b (0x4)
32 B
5
Minimum permitted size
01001b (0x9)
1 KB
10
-
10011b (0x13)
1 MB
20
-
11101b (0x1D)
1 GB
30
-
11111b (0x1F)
4 GB
No valid ADDR field in MPUBASE; the Maximum possible size
region occupies the complete
memory map.
a. Refers to the N parameter in the MPUBASE register (see page 179).
MPU Region Attribute and Size (MPUATTR)
Base 0xE000.E000
Offset 0xDA0
Type R/W, reset 0x0000.0000
31
30
29
28
27
reserved
Type
Reset
26
25
24
23
AP
21
reserved
20
19
18
TEX
17
16
XN
reserved
S
C
B
RO
0
RO
0
RO
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
RO
0
RO
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
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
SRD
Type
Reset
22
reserved
SIZE
July 03, 2014
R/W
0
ENABLE
R/W
0
181
Texas Instruments-Production Data
Cortex-M3 Peripherals
Bit/Field
Name
Type
Reset
Description
31:29
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.
28
XN
R/W
0
Instruction Access Disable
Value Description
0
Instruction fetches are enabled.
1
Instruction fetches are disabled.
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
AP
R/W
0
Access Privilege
For information on using this bit field, see Table 3-5 on page 125.
23:22
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.
21:19
TEX
R/W
0x0
Type Extension Mask
For information on using this bit field, see Table 3-3 on page 124.
18
S
R/W
0
Shareable
For information on using this bit, see Table 3-3 on page 124.
17
C
R/W
0
Cacheable
For information on using this bit, see Table 3-3 on page 124.
16
B
R/W
0
Bufferable
For information on using this bit, see Table 3-3 on page 124.
15:8
SRD
R/W
0x00
Subregion Disable Bits
Value Description
0
The corresponding subregion is enabled.
1
The corresponding subregion is disabled.
Region sizes of 128 bytes and less do not support subregions. When
writing the attributes for such a region, configure the SRD field as 0x00.
See the section called “Subregions” on page 123 for more information.
7:6
reserved
RO
0x0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
5:1
SIZE
R/W
0x0
Region Size Mask
The SIZE field defines the size of the MPU memory region specified by
the MPUNUMBER register. Refer to Table 3-9 on page 181 for more
information.
182
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
0
ENABLE
R/W
0
Description
Region Enable
Value Description
0
The region is disabled.
1
The region is enabled.
July 03, 2014
183
Texas Instruments-Production Data
JTAG Interface
4
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 four pins: 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 Stellaris JTAG controller works with the ARM JTAG controller built into the Cortex-M3 core
by multiplexing the TDO outputs from both JTAG controllers. ARM JTAG instructions select the ARM
TDO output while Stellaris JTAG instructions select the Stellaris TDO output. The multiplexer is
controlled by the Stellaris JTAG controller, which has comprehensive programming for the ARM,
Stellaris, and unimplemented JTAG instructions.
The Stellaris 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, IDCODE, SAMPLE/PRELOAD, EXTEST and INTEST
■ ARM additional instructions: APACC, DPACC and ABORT
■ Integrated ARM Serial Wire Debug (SWD)
– Serial Wire JTAG Debug Port (SWJ-DP)
– Flash Patch and Breakpoint (FPB) unit for implementing breakpoints
– Data Watchpoint and Trace (DWT) unit for implementing watchpoints, trigger resources, and
system profiling
– Instrumentation Trace Macrocell (ITM) for support of printf style debugging
– Trace Port Interface Unit (TPIU) for bridging to a Trace Port Analyzer
See the ARM® Debug Interface V5 Architecture Specification for more information on the ARM
JTAG controller.
184
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
4.1
Block Diagram
Figure 4-1. JTAG Module Block Diagram
TCK
TMS
TAP Controller
TDI
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
4.2
Signal Description
The following table lists the external signals of the JTAG/SWD controller and describes the function
of each. The JTAG/SWD controller signals are alternate functions for some GPIO signals, however
note that the reset state of the pins is for the JTAG/SWD function. The JTAG/SWD controller signals
are under commit protection and require a special process to be configured as GPIOs, see “Commit
Control” on page 406. The column in the table below titled "Pin Mux/Pin Assignment" lists the GPIO
pin placement for the JTAG/SWD controller signals. The AFSEL bit in the GPIO Alternate Function
Select (GPIOAFSEL) register (page 421) is set to choose the JTAG/SWD function. The number in
parentheses is the encoding that must be programmed into the PMCn field in the GPIO Port Control
(GPIOPCTL) register (page 439) to assign the JTAG/SWD controller signals to the specified GPIO
port pin. For more information on configuring GPIOs, see “General-Purpose Input/Outputs
(GPIOs)” on page 397.
Table 4-1. JTAG_SWD_SWO Signals (100LQFP)
Pin Name
Pin Number Pin Mux / Pin
Assignment
a
Pin Type
Buffer Type
Description
SWCLK
80
PC0 (3)
I
TTL
JTAG/SWD CLK.
SWDIO
79
PC1 (3)
I/O
TTL
JTAG TMS and SWDIO.
SWO
77
PC3 (3)
O
TTL
JTAG TDO and SWO.
TCK
80
PC0 (3)
I
TTL
JTAG/SWD CLK.
TDI
78
PC2 (3)
I
TTL
JTAG TDI.
TDO
77
PC3 (3)
O
TTL
JTAG TDO and SWO.
July 03, 2014
185
Texas Instruments-Production Data
JTAG Interface
Table 4-1. JTAG_SWD_SWO Signals (100LQFP) (continued)
Pin Name
Pin Number Pin Mux / Pin
Assignment
79
TMS
a
Pin Type
Buffer Type
I
TTL
PC1 (3)
Description
JTAG TMS and SWDIO.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
Table 4-2. JTAG_SWD_SWO Signals (108BGA)
Pin Name
Pin Number Pin Mux / Pin
Assignment
a
Pin Type
Buffer Type
Description
A9
PC0 (3)
I
TTL
JTAG/SWD CLK.
SWDIO
B9
PC1 (3)
I/O
TTL
JTAG TMS and SWDIO.
SWO
A10
PC3 (3)
O
TTL
JTAG TDO and SWO.
TCK
A9
PC0 (3)
I
TTL
JTAG/SWD CLK.
SWCLK
TDI
B8
PC2 (3)
I
TTL
JTAG TDI.
TDO
A10
PC3 (3)
O
TTL
JTAG TDO and SWO.
TMS
B9
PC1 (3)
I
TTL
JTAG TMS and SWDIO.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
4.3
Functional Description
A high-level conceptual drawing of the JTAG module is shown in Figure 4-1 on page 185. 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 TCK and TMS inputs.
The current state of the TAP controller depends on 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 4-4 on page 192 for a list of implemented instructions).
See “JTAG and Boundary Scan” on page 1248 for JTAG timing diagrams.
Note:
4.3.1
Of all the possible reset sources, only Power-On reset (POR) and the assertion of the RST
input have any effect on the JTAG module. The pin configurations are reset by both the
RST input and POR, whereas the internal JTAG logic is only reset with POR. See “Reset
Sources” on page 197 for more information on reset.
JTAG Interface Pins
The JTAG interface consists of four standard pins: TCK, TMS, TDI, and TDO. These pins and their
associated state after a power-on reset or reset caused by the RST input are given in Table 4-3.
Detailed information on each pin follows. Refer to “General-Purpose Input/Outputs
(GPIOs)” on page 397 for information on how to reprogram the configuration of these pins.
186
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 4-3. JTAG Port Pins State after Power-On Reset or RST assertion
4.3.1.1
Pin Name
Data Direction
Internal Pull-Up
Internal Pull-Down
Drive Strength
Drive Value
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 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 and to ensure 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, assuring 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 (see page 427 and page 429).
4.3.1.2
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 may be
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
module and associated registers are reset to their default values. This procedure should be performed
to initialize the JTAG controller. The JTAG Test Access Port state machine can be seen in its entirety
in Figure 4-2 on page 188.
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 (see page 427).
4.3.1.3
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, may present 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 (see page 427).
4.3.1.4
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
July 03, 2014
187
Texas Instruments-Production Data
JTAG Interface
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, assuring 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 (see page 427 and page 429).
4.3.2
JTAG TAP Controller
The JTAG TAP controller state machine is shown in Figure 4-2. The TAP controller state machine
is reset to the Test-Logic-Reset state on the assertion of a Power-On-Reset (POR). In order to reset
the JTAG module after the microcontroller has been powered on, the TMS input must be held HIGH
for five TCK clock cycles, resetting the TAP controller and all associated JTAG chains. 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.
Figure 4-2. Test Access Port State Machine
Test Logic Reset
1
0
Run Test Idle
0
Select DR Scan
1
Select IR Scan
1
0
1
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
4.3.3
1
0
Pause DR
1
0
1
0
0
1
0
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
188
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
this information to be shifted out on 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 192.
4.3.4
Operational Considerations
Certain operational parameters must be considered 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.
4.3.4.1
GPIO Functionality
When the microcontroller 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 (DEN[3:0]
set in the Port C GPIO Digital Enable (GPIODEN) register), enabling the pull-up resistors (PUE[3:0]
set in the Port C GPIO Pull-Up Select (GPIOPUR) register), disabling the pull-down resistors
(PDE[3:0] cleared in the Port C GPIO Pull-Down Select (GPIOPDR) register) and enabling the
alternate hardware function (AFSEL[3:0] set in the Port C GPIO Alternate Function Select
(GPIOAFSEL) register) on the JTAG/SWD pins. See page 421, page 427, page 429, and page 432.
It is possible for software to configure these pins as GPIOs after reset by clearing AFSEL[3:0] in
the Port C GPIOAFSEL register. If the user does not require the JTAG/SWD port for debugging or
board-level testing, this provides four more GPIOs for use in the design.
Caution – 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. As a result, the debugger may be locked out of the part.
This issue can be avoided with a software routine that restores JTAG functionality based on an external
or software trigger.
The GPIO commit control registers provide a layer of protection against accidental programming of
critical hardware peripherals. Protection is provided for the NMI pin (PB7) and the four JTAG/SWD
pins (PC[3:0]). Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL)
register (see page 421), GPIO Pull Up Select (GPIOPUR) register (see page 427), GPIO Pull-Down
Select (GPIOPDR) register (see page 429), and GPIO Digital Enable (GPIODEN) register (see
page 432) are not committed to storage unless the GPIO Lock (GPIOLOCK) register (see page 434)
has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register (see page 435)
have been set.
4.3.4.2
Communication with JTAG/SWD
Because the debug clock and the system clock can be running at different frequencies, care must
be taken to maintain reliable communication with the JTAG/SWD interface. In the Capture-DR state,
the result of the previous transaction, if any, is returned, together with a 3-bit ACK response. Software
should check the ACK response to see if the previous operation has completed before initiating a
new transaction. Alternatively, if the system clock is at least 8 times faster than the debug clock
(TCK or SWCLK), the previous operation has enough time to complete and the ACK bits do not have
to be checked.
July 03, 2014
189
Texas Instruments-Production Data
JTAG Interface
4.3.4.3
Recovering a "Locked" Microcontroller
Note:
Performing the sequence below restores the non-volatile registers discussed in “Non-Volatile
Register Programming” on page 308 to their factory default values. The mass erase of the
Flash memory caused by the sequence below occurs prior to the non-volatile registers
being restored.
If software configures any of the JTAG/SWD pins as GPIO and loses the ability to communicate
with the debugger, there is a debug port unlock sequence that can be used to recover the
microcontroller. Performing a total of ten JTAG-to-SWD and SWD-to-JTAG switch sequences while
holding the microcontroller in reset mass erases the Flash memory. The debug port unlock sequence
is:
1. Assert and hold the RST signal.
2. Apply power to the device.
3. Perform steps 1 and 2 of the JTAG-to-SWD switch sequence on the section called “JTAG-to-SWD
Switching” on page 191.
4. Perform steps 1 and 2 of the SWD-to-JTAG switch sequence on the section called “SWD-to-JTAG
Switching” on page 191.
5. Perform steps 1 and 2 of the JTAG-to-SWD switch sequence.
6. Perform steps 1 and 2 of the SWD-to-JTAG switch sequence.
7. Perform steps 1 and 2 of the JTAG-to-SWD switch sequence.
8. Perform steps 1 and 2 of the SWD-to-JTAG switch sequence.
9. Perform steps 1 and 2 of the JTAG-to-SWD switch sequence.
10. Perform steps 1 and 2 of the SWD-to-JTAG switch sequence.
11. Perform steps 1 and 2 of the JTAG-to-SWD switch sequence.
12. Perform steps 1 and 2 of the SWD-to-JTAG switch sequence.
13. Release the RST signal.
14. Wait 400 ms.
15. Power-cycle the microcontroller.
4.3.4.4
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 integration is accomplished with a SWD preamble that is issued
before the SWD session begins.
The switching 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.
190
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Stepping through this sequence 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®
Debug Interface V5 Architecture Specification.
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 instance is the only one
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 the switching preamble to the microcontroller. The 16-bit
TMS/SWDIO command for switching to SWD mode is defined as b1110.0111.1001.1110, transmitted
LSB first. This command can also be represented as 0xE79E 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 High to ensure that both JTAG and SWD
are in their reset states.
2. Send the 16-bit JTAG-to-SWD switch command, 0xE79E, on TMS/SWDIO.
3. Send at least 50 TCK/SWCLK cycles with TMS/SWDIO High to ensure that if SWJ-DP was already
in SWD mode before sending the switch sequence, the SWD goes into the line reset state.
To verify that the Debug Access Port (DAP) has switched to the Serial Wire Debug (SWD) operating
mode, perform a SWD READID operation. The ID value can be compared against the device's
known ID to verify the switch.
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 command to the microcontroller. The 16-bit TMS/SWDIO
command for switching to JTAG mode is defined as b1110.0111.0011.1100, transmitted LSB first.
This command can also be represented as 0xE73C 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 High to ensure that both JTAG and SWD
are in their reset states.
2. Send the 16-bit SWD-to-JTAG switch command, 0xE73C, on TMS/SWDIO.
3. Send at least 50 TCK/SWCLK cycles with TMS/SWDIO High to ensure that if SWJ-DP was already
in JTAG mode before sending the switch sequence, the JTAG goes into the Test Logic Reset
state.
To verify that the Debug Access Port (DAP) has switched to the JTAG operating mode, set the
JTAG Instruction Register (IR) to the IDCODE instruction and shift out the Data Register (DR). The
DR value can be compared against the device's known IDCODE to verify the switch.
4.4
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
July 03, 2014
191
Texas Instruments-Production Data
JTAG Interface
application changes these pins to their GPIO function, they must be configured back to their JTAG
functionality before JTAG communication can be restored. To return the pins to their JTAG functions,
enable the four JTAG pins (PC[3:0]) for their alternate function using the GPIOAFSEL register.
In addition to enabling the alternate functions, any other changes to the GPIO pad configurations
on the four JTAG pins (PC[3:0]) should be returned to their default settings.
4.5
Register Descriptions
The registers in the JTAG TAP Controller or Shift Register chains are not memory mapped and are
not accessible through the on-chip Advanced Peripheral Bus (APB). Instead, the registers within
the JTAG controller are all accessed serially through the TAP Controller. These registers include
the Instruction Register and the six Data Registers.
4.5.1
Instruction Register (IR)
The JTAG TAP Instruction Register (IR) is a four-bit serial scan chain connected between the JTAG
TDI and TDO pins with a parallel load register. When the TAP Controller is placed in the correct
states, bits can be shifted into the IR. Once these bits have been shifted into the chain and updated,
they are interpreted as the current instruction. The decode of the IR bits is shown in Table 4-4. A
detailed explanation of each instruction, along with its associated Data Register, follows.
Table 4-4. JTAG Instruction Register Commands
4.5.1.1
IR[3:0]
Instruction
Description
0x0
EXTEST
Drives the values preloaded into the Boundary Scan Chain by the
SAMPLE/PRELOAD instruction onto the pads.
0x1
INTEST
Drives the values preloaded into the Boundary Scan Chain by the
SAMPLE/PRELOAD instruction into the controller.
0x2
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.
0x8
ABORT
Shifts data into the ARM Debug Port Abort Register.
0xA
DPACC
Shifts data into and out of the ARM DP Access Register.
0xB
APACC
Shifts data into and out of the ARM AC Access Register.
0xE
IDCODE
Loads manufacturing information defined by the IEEE Standard 1149.1 into
the IDCODE chain and shifts it out.
0xF
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 is not associated with its own Data Register chain. Instead, 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. With tests
that drive known values out of the controller, this instruction can be used to verify connectivity. While
the EXTEST instruction is present in the Instruction Register, the Boundary Scan Data Register can
be accessed to sample and shift out the current data and load new data into the Boundary Scan
Data Register.
192
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
4.5.1.2
INTEST Instruction
The INTEST instruction is not associated with its own Data Register chain. Instead, 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. With tests that
drive known values into the controller, this instruction 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.
While the INTEST instruction is present in the Instruction Register, the Boundary Scan Data Register
can be accessed to sample and shift out the current data and load new data into the Boundary Scan
Data Register.
4.5.1.3
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 on 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. See “Boundary Scan Data
Register” on page 195 for more information.
4.5.1.4
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. See the “ABORT Data Register” on page 195 for more information.
4.5.1.5
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. See “DPACC Data
Register” on page 195 for more information.
4.5.1.6
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.
See “APACC Data Register” on page 195 for more information.
July 03, 2014
193
Texas Instruments-Production Data
JTAG Interface
4.5.1.7
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 input and output data streams. IDCODE is the default instruction loaded into the JTAG
Instruction Register when a Power-On-Reset (POR) is asserted, or the Test-Logic-Reset state is
entered. See “IDCODE Data Register” on page 194 for more information.
4.5.1.8
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. See “BYPASS Data Register” on page 194 for more
information.
4.5.2
Data Registers
The JTAG module contains six Data Registers. These serial Data Register chains include: IDCODE,
BYPASS, Boundary Scan, APACC, DPACC, and ABORT and are discussed in the following sections.
4.5.2.1
IDCODE Data Register
The format for the 32-bit IDCODE Data Register defined by the IEEE Standard 1149.1 is shown in
Figure 4-3. The standard requires that every JTAG-compliant microcontroller 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 definition 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 0x4BA0.0477. This value allows the debuggers to automatically
configure themselves to work correctly with the Cortex-M3 during debug.
Figure 4-3. IDCODE Register Format
31
TDI
4.5.2.2
28 27
12 11
Version
Part Number
1 0
Manufacturer ID
1
TDO
BYPASS Data Register
The format for the 1-bit BYPASS Data Register defined by the IEEE Standard 1149.1 is shown in
Figure 4-4. The standard requires that every JTAG-compliant microcontroller 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 definition allows auto-configuration test tools to determine which instruction is the default
instruction.
194
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 4-4. BYPASS Register Format
0
0
TDI
4.5.2.3
TDO
Boundary Scan Data Register
The format of the Boundary Scan Data Register is shown in Figure 4-5. Each GPIO pin, starting
with a GPIO pin next to 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 shown in the figure.
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. The EXTEST instruction forces data out of the controller,
and the INTEST instruction forces data into the controller.
Figure 4-5. Boundary Scan Register Format
TDI
I
N
O
U
T
O
E
...
1st GPIO
4.5.2.4
I
N
O
U
T
mth GPIO
O
E
I
N
O
U
T
(m+1)th GPIO
O
E
...
I
N
O
U
T
O
E
TDO
GPIO nth
APACC Data Register
The format for the 35-bit APACC Data Register defined by ARM is described in the ARM® Debug
Interface V5 Architecture Specification.
4.5.2.5
DPACC Data Register
The format for the 35-bit DPACC Data Register defined by ARM is described in the ARM® Debug
Interface V5 Architecture Specification.
4.5.2.6
ABORT Data Register
The format for the 35-bit ABORT Data Register defined by ARM is described in the ARM® Debug
Interface V5 Architecture Specification.
July 03, 2014
195
Texas Instruments-Production Data
System Control
5
System Control
System control configures the overall operation of the device and provides information about the
device. Configurable features include reset control, NMI operation, power control, clock control, and
low-power modes.
5.1
Signal Description
The following table lists the external signals of the System Control module and describes the function
of each. The NMI signal is the alternate function for the GPIO PB7 signal and functions as a GPIO
after reset. PB7 is under commit protection and requires a special process to be configured as any
alternate function or to subsequently return to the GPIO function, see “Commit Control” on page 406.
The column in the table below titled "Pin Mux/Pin Assignment" lists the GPIO pin placement for the
NMI signal. The AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register (page 421)
should be set to choose the NMI function. The number in parentheses is the encoding that must be
programmed into the PMCn field in the GPIO Port Control (GPIOPCTL) register (page 439) to assign
the NMI signal to the specified GPIO port pin. For more information on configuring GPIOs, see
“General-Purpose Input/Outputs (GPIOs)” on page 397. The remaining signals (with the word "fixed"
in the Pin Mux/Pin Assignment column) have a fixed pin assignment and function.
Table 5-1. System Control & Clocks Signals (100LQFP)
Pin Name
Pin Number Pin Mux / Pin
Assignment
a
Pin Type
Buffer Type
Description
NMI
89
PB7 (4)
I
TTL
Non-maskable interrupt.
OSC0
48
fixed
I
Analog
Main oscillator crystal input or an external clock
reference input.
OSC1
49
fixed
O
Analog
Main oscillator crystal output. Leave unconnected
when using a single-ended clock source.
RST
64
fixed
I
TTL
System reset input.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
Table 5-2. System Control & Clocks Signals (108BGA)
Pin Name
Pin Number Pin Mux / Pin
Assignment
a
Pin Type
Buffer Type
Description
NMI
A8
PB7 (4)
I
TTL
Non-maskable interrupt.
OSC0
L11
fixed
I
Analog
Main oscillator crystal input or an external clock
reference input.
OSC1
M11
fixed
O
Analog
Main oscillator crystal output. Leave unconnected
when using a single-ended clock source.
RST
H11
fixed
I
TTL
System reset input.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
5.2
Functional Description
The System Control module provides the following capabilities:
■ Device identification, see “Device Identification” on page 197
■ Local control, such as reset (see “Reset Control” on page 197), power (see “Power
Control” on page 202) and clock control (see “Clock Control” on page 203)
196
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ System control (Run, Sleep, and Deep-Sleep modes), see “System Control” on page 209
5.2.1
Device Identification
Several read-only registers provide software with information on the microcontroller, such as version,
part number, SRAM size, Flash memory size, and other features. See the DID0 (page 214), DID1
(page 242), DC0-DC9 (page 244) and NVMSTAT (page 267) registers.
5.2.2
Reset Control
This section discusses aspects of hardware functions during reset as well as system software
requirements following the reset sequence.
5.2.2.1
Reset Sources
The LM3S5791 microcontroller has six sources of reset:
1. Power-on reset (POR) (see page 198).
2. External reset input pin (RST) assertion (see page 198).
3. Internal brown-out (BOR) detector (see page 200).
4. Software-initiated reset (with the software reset registers) (see page 200).
5. A watchdog timer reset condition violation (see page 201).
6. MOSC failure (see page 202).
Table 5-3 provides a summary of results of the various reset operations.
Table 5-3. Reset Sources
Core Reset?
JTAG Reset?
On-Chip Peripherals Reset?
Power-On Reset
Reset Source
Yes
Yes
Yes
RST
Yes
Yes
Yes
Brown-Out Reset
Yes
Yes
Yes
Software System Request
Reset using the SYSRESREQ
bit in the APINT register.
Yes
Yes
Yes
Software System Request
Reset using the VECTRESET
bit in the APINT register.
Yes
No
No
Software Peripheral Reset
No
Yes
Yes
Watchdog Reset
Yes
Yes
Yes
MOSC Failure Reset
Yes
Yes
Yes
a
a. Programmable on a module-by-module basis using the Software Reset Control Registers.
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
or an external reset is the cause, and then all the other bits in the RESC register are cleared except
for the POR or EXT indicator.
July 03, 2014
197
Texas Instruments-Production Data
System Control
At any reset that resets the core, the user has the opportunity to direct the core to execute the ROM
Boot Loader or the application in Flash memory by using any GPIO signal as configured in the Boot
Configuration (BOOTCFG) register.
At reset, the ROM is mapped over the Flash memory so that the ROM boot sequence is always
executed. The boot sequence executed from ROM is as follows:
1. The BA bit (below) is cleared such that ROM is mapped to 0x01xx.xxxx and Flash memory is
mapped to address 0x0.
2. The BOOTCFG register is read. If the EN bit is clear, the status of the specified GPIO pin is
compared with the specified polarity. If the status matches the specified polarity, the ROM is
mapped to address 0x0000.0000 and execution continues out of the ROM Boot Loader.
3. If the status doesn't match the specified polarity, the data at address 0x0000.0004 is read, and
if the data at this address is 0xFFFF.FFFF, the ROM is mapped to address 0x0000.0000 and
execution continues out of the ROM Boot Loader.
4. If there is valid data at address 0x0000.0004, the stack pointer (SP) is loaded from Flash memory
at address 0x0000.0000 and the program counter (PC) is loaded from address 0x0000.0004.
The user application begins executing.
For example, if the BOOTCFG register is written and committed with the value of 0x0000.3C01,
then PB7 is examined at reset to determine if the ROM Boot Loader should be executed. If PB7 is
Low, the core unconditionally begins executing the ROM boot loader. If PB7 is High, then the
application in Flash memory is executed if the reset vector at location 0x0000.0004 is not
0xFFFF.FFFF. Otherwise, the ROM boot loader is executed.
5.2.2.2
Power-On Reset (POR)
The internal Power-On Reset (POR) circuit monitors the power supply voltage (VDD) and generates
a reset signal to all of the internal logic including JTAG when the power supply ramp reaches a
threshold value (VTH). The microcontroller must be operating within the specified operating parameters
when the on-chip power-on reset pulse is complete (see “Power and Brown-Out” on page 1250). For
applications that require the use of an external reset signal to hold the microcontroller in reset longer
than the internal POR, the RST input may be used as discussed in “External RST Pin” on page 198.
The Power-On Reset sequence is as follows:
1. The microcontroller waits for 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, and the first instruction designated by the program counter, and then begins
execution.
The internal POR is only active on the initial power-up of the microcontroller. The Power-On Reset
timing is shown in Figure 25-4 on page 1250.
5.2.2.3
External RST Pin
Note:
It is recommended that the trace for the RST signal must be kept as short as possible. Be
sure to place any components connected to the RST signal as close to the microcontroller
as possible.
If the application only uses the internal POR circuit, the RST input must be connected to the power
supply (VDD) through an optional pull-up resistor (0 to 100K Ω) as shown in Figure 5-1 on page 199.
198
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 5-1. Basic RST Configuration
VDD
Stellaris®
RPU
RST
RPU = 0 to 100 kΩ
The external reset pin (RST) resets the microcontroller including the core and all the on-chip
peripherals except the JTAG TAP controller (see “JTAG Interface” on page 184). The external reset
sequence is as follows:
1. The external reset pin (RST) is asserted for the duration specified by TMIN and then de-asserted
(see “Reset” on page 1251).
2. The internal reset is released and the core loads from memory the initial stack pointer, the initial
program counter, and the first instruction designated by the program counter, and then begins
execution.
To improve noise immunity and/or to delay reset at power up, the RST input may be connected to
an RC network as shown in Figure 5-2 on page 199.
Figure 5-2. External Circuitry to Extend Power-On Reset
VDD
Stellaris®
RPU
RST
C1
RPU = 1 kΩ to 100 kΩ
C1 = 1 nF to 10 µF
If the application requires the use of an external reset switch, Figure 5-3 on page 200 shows the
proper circuitry to use.
July 03, 2014
199
Texas Instruments-Production Data
System Control
Figure 5-3. Reset Circuit Controlled by Switch
VDD
Stellaris®
RPU
RST
C1
RS
Typical RPU = 10 kΩ
Typical RS = 470 Ω
C1 = 10 nF
The RPU and C1 components define the power-on delay.
The external reset timing is shown in Figure 25-7 on page 1251.
5.2.2.4
Brown-Out Reset (BOR)
The microcontroller 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 an interrupt or a system reset. The default condition is to generate an interrupt, so
BOR must be enabled. 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; if BORIOR is clear, an interrupt is generated. When a Brown-out condition
occurs during a Flash PROGRAM or ERASE operation, a full system reset is always triggered
without regard to the setting in the PBORCTL register.
The brown-out reset sequence is as follows:
1. When VDD drops below VBTH, an internal BOR condition is set.
2. If the BOR condition exists, an internal reset is asserted.
3. The internal reset is released and the microcontroller fetches and loads the initial stack pointer,
the initial program counter, the first instruction designated by the program counter, and begins
execution.
4. The internal BOR condition is reset after 500 µs to prevent another BOR condition from being
set before software has a chance to investigate the original cause.
The result of a brown-out reset is equivalent to that of 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 25-5 on page 1250.
5.2.2.5
Software Reset
Software can reset a specific peripheral or generate a reset to the entire microcontroller.
200
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Peripherals can be individually reset by software via three registers that control reset signals to each
on-chip peripheral (see the SRCRn registers, page 294). If the bit position corresponding to a
peripheral is set and subsequently cleared, 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 209).
The entire microcontroller, including the core, can be reset by software by setting the SYSRESREQ
bit in the Application Interrupt and Reset Control (APINT) register. The software-initiated system
reset sequence is as follows:
1. A software microcontroller reset is initiated by setting the SYSRESREQ bit.
2. An internal reset is asserted.
3. The internal reset is deasserted and the microcontroller 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 core only can be reset by software by setting the VECTRESET bit in the APINT register. The
software-initiated core reset sequence is as follows:
1. A core reset is initiated by setting the VECTRESET bit.
2. An internal reset is asserted.
3. The internal reset is deasserted and the microcontroller 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 25-8 on page 1251.
5.2.2.6
Watchdog Timer Reset
The Watchdog Timer module's function is to prevent system hangs. The LM3S5791 microcontroller
has two Watchdog Timer modules in case one watchdog clock source fails. One watchdog is run
off the system clock and the other is run off the Precision Internal Oscillator (PIOSC). Each module
operates in the same manner except that because the PIOSC watchdog timer module is in a different
clock domain, register accesses must have a time delay between them. The watchdog timer can
be configured to generate an interrupt to the microcontroller on its first time-out and to generate a
reset on its second time-out.
After the watchdog's first time-out event, the 32-bit watchdog counter is reloaded with the value of
the Watchdog Timer Load (WDTLOAD) register and resumes counting down from that value. If
the timer counts down to zero 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 microcontroller. 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 microcontroller loads from memory the initial stack pointer,
the initial program counter, and the first instruction designated by the program counter, and
then begins execution.
For more information on the Watchdog Timer module, see “Watchdog Timers” on page 573.
July 03, 2014
201
Texas Instruments-Production Data
System Control
The watchdog reset timing is shown in Figure 25-9 on page 1252.
5.2.3
Non-Maskable Interrupt
The microcontroller has three sources of non-maskable interrupt (NMI):
■ The assertion of the NMI signal
■ A main oscillator verification error
■ The NMISET bit in the Interrupt Control and State (INTCTRL) register in the Cortex™-M3 (see
page 149).
Software must check the cause of the interrupt in order to distinguish among the sources.
5.2.3.1
NMI Pin
The NMI signal is the alternate function for GPIO port pin PB7. The alternate function must be
enabled in the GPIO for the signal to be used as an interrupt, as described in “General-Purpose
Input/Outputs (GPIOs)” on page 397. Note that enabling the NMI alternate function requires the use
of the GPIO lock and commit function just like the GPIO port pins associated with JTAG/SWD
functionality, see page 435. The active sense of the NMI signal is High; asserting the enabled NMI
signal above VIH initiates the NMI interrupt sequence.
5.2.3.2
Main Oscillator Verification Failure
The LM3S5791 microcontroller provides a main oscillator verification circuit that generates an error
condition if the oscillator is running too fast or too slow. If the main oscillator verification circuit is
enabled and a failure occurs, a power-on reset is generated and control is transferred to the NMI
handler. The NMI handler is used to address the main oscillator verification failure because the
necessary code can be removed from the general reset handler, speeding up reset processing. The
detection circuit is enabled by setting the CVAL bit in the Main Oscillator Control (MOSCCTL)
register. The main oscillator verification error is indicated in the main oscillator fail status (MOSCFAIL)
bit in the Reset Cause (RESC) register. The main oscillator verification circuit action is described
in more detail in “Main Oscillator Verification Circuit” on page 209.
5.2.4
Power Control
®
The Stellaris microcontroller provides an integrated LDO regulator that is used to provide power
to the majority of the microcontroller's internal logic. Figure 5-4 shows the power architecture.
An external LDO may not be used.
Note:
VDDA must be supplied with a voltage that meets the specification in Table 25-2 on page 1247,
or the microcontroller does not function properly. VDDA is the supply for all of the analog
circuitry on the device, including the clock circuitry.
202
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 5-4. Power Architecture
VDDC
Internal
Logic and PLL
VDDC
GND
GND
LDO
Low-Noise
LDO
+3.3V
VDD
GND
I/O Buffers
VDD
GND
VDDA
GNDA
Analog Circuits
VDDA
5.2.5
GNDA
Clock Control
System control determines the control of clocks in this part.
5.2.5.1
Fundamental Clock Sources
There are multiple clock sources for use in the microcontroller:
■ Precision Internal Oscillator (PIOSC). The precision internal oscillator is an on-chip clock
source that is the clock source the microcontroller uses during and following POR. It does not
require the use of any external components and provides a clock that is 16 MHz ±1% at room
temperature and ±3% across temperature. The PIOSC allows for a reduced system cost in
applications that require an accurate clock source. 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 (MOSC). 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. If the PLL is being
used, the crystal value must be one of the supported frequencies between 3.579545 MHz to
16.384 MHz (inclusive). If the PLL is not being used, the crystal may be any one of the supported
frequencies between 1 MHz to 16.384 MHz. The single-ended clock source range is from DC
July 03, 2014
203
Texas Instruments-Production Data
System Control
through the specified speed of the microcontroller. The supported crystals are listed in the XTAL
bit field in the RCC register (see page 225). Note that the MOSC provides the clock source for
the USB PLL and must be connected to a crystal or an oscillator.
■ Internal 30-kHz Oscillator. The internal 30-kHz oscillator provides an operational frequency of
30 kHz ± 50%. It is intended for use during Deep-Sleep power-saving modes. This power-savings
mode benefits from reduced internal switching and also allows the MOSC to be powered down.
The internal system clock (SysClk), is derived from any of the above sources plus two others: the
output of the main internal PLL and the precision internal oscillator divided by four (4 MHz ± 1%).
The frequency of the PLL clock reference must be in the range of 3.579545 MHz to 16.384 MHz
(inclusive). Table 5-4 on page 204 shows how the various clock sources can be used in a system.
Table 5-4. Clock Source Options
5.2.5.2
Clock Source
Drive PLL?
Used as SysClk?
Precision Internal Oscillator
Yes
BYPASS = 0, OSCSRC
= 0x1
Yes
BYPASS = 1, OSCSRC = 0x1
Precision Internal Oscillator divide
by 4 (4 MHz ± 1%)
No
-
Yes
BYPASS = 1, OSCSRC = 0x2
Main Oscillator
Yes
BYPASS = 0, OSCSRC
= 0x0
Yes
BYPASS = 1, OSCSRC = 0x0
Internal 30-kHz Oscillator
No
-
Yes
BYPASS = 1, OSCSRC = 0x3
Clock Configuration
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. These registers control the following clock
functionality:
■ Source of clocks in sleep and deep-sleep modes
■ System clock derived from PLL or other clock source
■ Enabling/disabling of oscillators and PLL
■ Clock divisors
■ Crystal input selection
Important: Write the RCC register prior to writing the RCC2 register. If a subsequent write to the
RCC register is required, include another register access after writing the RCC register
and before writing the RCC2 register.
Figure 5-5 shows the logic for the main clock tree. The peripheral blocks are driven by the system
clock signal and can be individually enabled/disabled. When the PLL is enabled, the ADC clock
signal is automatically divided down to 16 MHz from the PLL output for proper ADC operation. The
PWM clock signal is a synchronous divide of the system clock to provide the PWM circuit with more
range (set with PWMDIV in RCC).
204
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Note:
When the ADC module is in operation, the system clock must be at least 16 MHz. When
the USB module is in operation, MOSC must be the clock source, either with or without
using the PLL, and the system clock must be at least 30 MHz.
Figure 5-5. Main Clock Tree
XTALa
USBPWRDN c
USB PLL
(480 MHz)
÷4
USB Clock
RXINT
RXFRAC
I2S Receive MCLK
TXINT
TXFRAC
I2S Transmit MCLK
USEPWMDIV a
PWMDW a
PWM Clock
XTALa
PWRDN b
MOSCDIS a
PLL
(400 MHz)
Main OSC
USESYSDIV a,d
DIV400 c
÷2
IOSCDIS
a
System Clock
Precision
Internal OSC
(16 MHz)
SYSDIV e
÷4
BYPASS
b,d
Internal OSC
(30 kHz)
Hibernation
OSC
(32.768 kHz)
PWRDN
ADC Clock
OSCSRC b,d
÷ 25
a. Control provided by RCC register bit/field.
b. Control provided by RCC register bit/field or RCC2 register bit/field, if overridden with RCC2 register bit USERCC2.
c. Control provided by RCC2 register bit/field.
d. Also may be controlled by DSLPCLKCFG when in deep sleep mode.
e. Control provided by RCC register SYSDIV field, RCC2 register SYSDIV2 field if overridden with USERCC2 bit, or
[SYSDIV2,SYSDIV2LSB] if both USERCC2 and DIV400 bits are set.
Note:
The figure above shows all features available on all Stellaris® Tempest-class microcontrollers. Not all peripherals
may be available on this device.
July 03, 2014
205
Texas Instruments-Production Data
System Control
Using the SYSDIV and SYSDIV2 Fields
In the RCC register, the SYSDIV field specifies which divisor is used to generate the system clock
from either the PLL output or the oscillator source (depending on how the BYPASS bit in this register
is configured). When using the PLL, the VCO frequency of 400 MHz is predivided by 2 before the
divisor is applied. Table 5-5 shows how the SYSDIV encoding affects the system clock frequency,
depending on whether the PLL is used (BYPASS=0) or another clock source is used (BYPASS=1).
The divisor is equivalent to the SYSDIV encoding plus 1. For a list of possible clock sources, see
Table 5-4 on page 204.
Table 5-5. Possible System Clock Frequencies Using the SYSDIV Field
SYSDIV
Divisor
Frequency (BYPASS=0) Frequency (BYPASS=1)
a
®
StellarisWare Parameter
0x0
/1
reserved
Clock source frequency/1
SYSCTL_SYSDIV_1
0x1
/2
reserved
Clock source frequency/2
SYSCTL_SYSDIV_2
0x2
/3
66.67 MHz
Clock source frequency/3
SYSCTL_SYSDIV_3
0x3
/4
50 MHz
Clock source frequency/4
SYSCTL_SYSDIV_4
0x4
/5
40 MHz
Clock source frequency/5
SYSCTL_SYSDIV_5
0x5
/6
33.33 MHz
Clock source frequency/6
SYSCTL_SYSDIV_6
0x6
/7
28.57 MHz
Clock source frequency/7
SYSCTL_SYSDIV_7
0x7
/8
25 MHz
Clock source frequency/8
SYSCTL_SYSDIV_8
0x8
/9
22.22 MHz
Clock source frequency/9
SYSCTL_SYSDIV_9
0x9
/10
20 MHz
Clock source frequency/10
SYSCTL_SYSDIV_10
0xA
/11
18.18 MHz
Clock source frequency/11
SYSCTL_SYSDIV_11
0xB
/12
16.67 MHz
Clock source frequency/12
SYSCTL_SYSDIV_12
0xC
/13
15.38 MHz
Clock source frequency/13
SYSCTL_SYSDIV_13
0xD
/14
14.29 MHz
Clock source frequency/14
SYSCTL_SYSDIV_14
0xE
/15
13.33 MHz
Clock source frequency/15
SYSCTL_SYSDIV_15
0xF
/16
12.5 MHz (default)
Clock source frequency/16
SYSCTL_SYSDIV_16
a. This parameter is used in functions such as SysCtlClockSet() in the Stellaris Peripheral Driver Library.
The SYSDIV2 field in the RCC2 register is 2 bits wider than the SYSDIV field in the RCC register
so that additional larger divisors up to /64 are possible, allowing a lower system clock frequency for
improved Deep Sleep power consumption. When using the PLL, the VCO frequency of 400 MHz is
predivided by 2 before the divisor is applied. The divisor is equivalent to the SYSDIV2 encoding
plus 1. Table 5-6 shows how the SYSDIV2 encoding affects the system clock frequency, depending
on whether the PLL is used (BYPASS2=0) or another clock source is used (BYPASS2=1). For a list
of possible clock sources, see Table 5-4 on page 204.
Table 5-6. Examples of Possible System Clock Frequencies Using the SYSDIV2 Field
SYSDIV2
Divisor
a
Frequency
(BYPASS2=0)
Frequency (BYPASS2=1)
StellarisWare Parameter
0x00
/1
reserved
Clock source frequency/1
SYSCTL_SYSDIV_1
0x01
/2
reserved
Clock source frequency/2
SYSCTL_SYSDIV_2
0x02
/3
66.67 MHz
Clock source frequency/3
SYSCTL_SYSDIV_3
0x03
/4
50 MHz
Clock source frequency/4
SYSCTL_SYSDIV_4
0x04
/5
40 MHz
Clock source frequency/5
SYSCTL_SYSDIV_5
...
...
...
...
...
206
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 5-6. Examples of Possible System Clock Frequencies Using the SYSDIV2 Field
(continued)
Divisor
a
Frequency
(BYPASS2=0)
Frequency (BYPASS2=1)
StellarisWare Parameter
/10
20 MHz
Clock source frequency/10
SYSCTL_SYSDIV_10
...
...
...
...
...
0x3F
/64
3.125 MHz
Clock source frequency/64
SYSCTL_SYSDIV_64
SYSDIV2
0x09
a. This parameter is used in functions such as SysCtlClockSet() in the Stellaris Peripheral Driver Library.
To allow for additional frequency choices when using the PLL, the DIV400 bit is provided along
with the SYSDIV2LSB bit. When the DIV400 bit is set, bit 22 becomes the LSB for SYSDIV2. In
this situation, the divisor is equivalent to the (SYSDIV2 encoding with SYSDIV2LSB appended) plus
one. Table 5-7 shows the frequency choices when DIV400 is set. When the DIV400 bit is clear,
SYSDIV2LSB is ignored, and the system clock frequency is determined as shown in Table
5-6 on page 206.
Table 5-7. Examples of Possible System Clock Frequencies with DIV400=1
/2
reserved
-
/3
reserved
-
1
/4
reserved
-
0
/5
80 MHz
SYSCTL_SYSDIV_2_5
1
/6
66.67 MHz
SYSCTL_SYSDIV_3
0
/7
reserved
-
1
/8
50 MHz
SYSCTL_SYSDIV_4
0
/9
44.44 MHz
SYSCTL_SYSDIV_4_5
1
/10
40 MHz
SYSCTL_SYSDIV_5
...
...
...
...
0
/127
3.15 MHz
SYSCTL_SYSDIV_63_5
1
/128
3.125 MHz
SYSCTL_SYSDIV_64
0x00
reserved
0
0x01
0x02
0x03
0x04
...
0x3F
b
StellarisWare Parameter
SYSDIV2LSB
Divisor
a
Frequency (BYPASS2=0)
SYSDIV2
a. Note that DIV400 and SYSDIV2LSB are only valid when BYPASS2=0.
b. This parameter is used in functions such as SysCtlClockSet() in the Stellaris Peripheral Driver Library.
5.2.5.3
Precision Internal Oscillator Operation (PIOSC)
The microcontroller powers up with the PIOSC running. If another clock source is desired, the PIOSC
must remain enabled as it is used for internal functions. The PIOSC can only be disabled during
Deep-Sleep mode. It can be powered down by setting the IOSCDIS bit in the RCC register.
The PIOSC generates a 16-MHz clock with a ±1% accuracy at room temperatures. Across the
extended temperature range, the accuracy is ±3%. At the factory, the PIOSC is set to 16 MHz at
room temperature, however, the frequency can be trimmed for other voltage or temperature conditions
using software in one of two ways:
■ Default calibration: clear the UTEN bit and set the UPDATE bit in the Precision Internal Oscillator
Calibration (PIOSCCAL) register.
■ User-defined calibration: The user can program the UT value to adjust the PIOSC frequency. As
the UT value increases, the generated period increases. To commit a new UT value, first set the
July 03, 2014
207
Texas Instruments-Production Data
System Control
UTEN bit, then program the UT field, and then set the UPDATE bit. The adjustment finishes within
a few clock periods and is glitch free.
5.2.5.4
Crystal Configuration for the Main Oscillator (MOSC)
The main oscillator supports the use of a select number of crystals. If the main oscillator is used by
the PLL as a reference clock, the supported range of crystals is 3.579545 to 16.384 MHz, otherwise,
the range of supported crystals is 1 to 16.384 MHz.
The XTAL bit in the RCC register (see page 225) 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.
5.2.5.5
Main PLL Frequency Configuration
The main PLL is disabled by default during power-on reset and is enabled later by software if
required. Software specifies the output divisor to set the system clock frequency and enables the
main PLL to drive the output. The PLL operates at 400 MHz, but is divided by two prior to the
application of the output divisor, unless the DIV400 bit in the RCC2 register is set.
To configure the PIOSC to be the clock source for the main PLL, program the OSCRC2 field in the
Run-Mode Clock Configuration 2 (RCC2) register to be 0x1.
If the main oscillator provides the clock reference to the main 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 230). The internal translation provides a translation within ± 1% of the
targeted PLL VCO frequency. Table 25-8 on page 1253 shows the actual PLL frequency and error for
a given crystal choice.
The Crystal Value field (XTAL) in the Run-Mode Clock Configuration (RCC) register (see page 225)
describes the available crystal choices and default programming of the PLLCFG register. Any time
the XTAL field changes, the new settings are translated and the internal PLL settings are updated.
5.2.5.6
USB PLL Frequency Configuration
The USB PLL is disabled by default during power-on reset and is enabled later by software. The
USB PLL must be enabled and running for proper USB function. The main oscillator is the only clock
reference for the USB PLL. The USB PLL is enabled by clearing the USBPWRDN bit of the RCC2
register. The XTAL bit field (Crystal Value) of the RCC register describes the available crystal choices.
The main oscillator must be connected to one of the following crystal values in order to correctly
generate the USB clock: 4, 5, 6, 8, 10, 12, or 16 MHz. Only these crystals provide the necessary
USB PLL VCO frequency to conform with the USB timing specifications.
5.2.5.7
PLL Modes
Both PLLs have 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 225 and page 233).
208
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
5.2.5.8
PLL Operation
If a 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
25-7 on page 1252). During the relock time, the affected PLL is not usable as a clock reference.
Either 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 clocked by the system clock is used to measure the TREADY requirement. If the system
clock is the main oscillator and it is running off an 8.192 MHz or slower external oscillator clock, the
down counter is set to 0x1200 (that is, ~600 μs at an 8.192 MHz). If the system clock is running off
the PIOSC or an external oscillator clock that is faster than 8.192 MHz, the down counter is set to
0x2400. 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 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.
If the main PLL is enabled and the system clock is switched to use the PLL in one step, the system
control hardware continues to clock the microcontroller from the oscillator selected by the RCC/RCC2
register until the main PLL is stable (TREADY time met), after which it changes to the PLL. Software
can use many methods to ensure that the system is clocked from the main PLL, including periodically
polling the PLLLRIS bit in the Raw Interrupt Status (RIS) register, and enabling the PLL Lock
interrupt.
The USB PLL is not protected during the lock time (TREADY), and software should ensure that the
USB PLL has locked before using the interface. Software can use many methods to ensure the
TREADY period has passed, including periodically polling the USBPLLLRIS bit in the Raw Interrupt
Status (RIS) register, and enabling the USB PLL Lock interrupt.
5.2.5.9
Main Oscillator Verification Circuit
The clock control includes circuitry to ensure that the main oscillator is running at the appropriate
frequency. The circuit monitors the main oscillator frequency and signals if the frequency is outside
of the allowable band of attached crystals.
The detection circuit is enabled using the CVAL bit in the Main Oscillator Control (MOSCCTL)
register. If this circuit is enabled and detects an error, the following sequence is performed by the
hardware:
1. The MOSCFAIL bit in the Reset Cause (RESC) register is set.
2. If the internal oscillator (PIOSC) is disabled, it is enabled.
3. The system clock is switched from the main oscillator to the PIOSC.
4. An internal power-on reset is initiated that lasts for 32 PIOSC periods.
5. Reset is de-asserted and the processor is directed to the NMI handler during the reset sequence.
5.2.6
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 microcontroller is in Run, Sleep, and
Deep-Sleep mode, respectively. These registers are located in the System Control register map
July 03, 2014
209
Texas Instruments-Production Data
System Control
starting at offsets 0x600, 0x700, and 0x800, respectively. There must be a delay of 3 system clocks
after a peripheral module clock is enabled in the RCGC register before any module registers are
accessed.
There are three levels of operation for the microcontroller defined as:
■ Run mode
■ Sleep mode
■ Deep-Sleep mode
The following sections describe the different modes in detail.
Caution – If the Cortex-M3 Debug Access Port (DAP) has been enabled, and the device wakes from a
low power sleep or deep-sleep mode, the core may start executing code before all clocks to peripherals
have been restored to their Run mode configuration. The DAP is usually enabled by software tools
accessing the JTAG or SWD interface when debugging or flash programming. If this condition occurs,
a Hard Fault is triggered when software accesses a peripheral with an invalid clock.
A software delay loop can be used at the beginning of the interrupt routine that is used to wake up a
system from a WFI (Wait For Interrupt) instruction. This stalls the execution of any code that accesses
a peripheral register that might cause a fault. This loop can be removed for production software as the
DAP is most likely not enabled during normal execution.
Because the DAP is disabled by default (power on reset), the user can also power cycle the device. The
DAP is not enabled unless it is enabled through the JTAG or SWD interface.
5.2.6.1
Run Mode
In Run mode, the microcontroller actively executes code. 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.
5.2.6.2
Sleep Mode
In Sleep mode, the clock frequency of the active peripherals is unchanged, but the processor and
the memory subsystem are not clocked and therefore no longer execute code. Sleep mode is entered
by the Cortex-M3 core executing a WFI (Wait for Interrupt) instruction. Any properly configured
interrupt event in the system brings the processor back into Run mode. See “Power
Management” on page 113 for more details.
Peripherals are clocked that are enabled in the SCGCn registers when auto-clock gating is enabled
(see the RCC register) or the RCGCn registers when the auto-clock gating is disabled. The system
clock has the same source and frequency as that during Run mode.
5.2.6.3
Deep-Sleep Mode
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 microcontroller to Run mode from one of the sleep modes; the sleep modes are entered on
request from the code. Deep-Sleep mode is entered by first setting the SLEEPDEEP bit in the System
Control (SYSCTRL) register (see page 155) and then executing a WFI instruction. Any properly
configured interrupt event in the system brings the processor back into Run mode. See “Power
Management” on page 113 for more details.
210
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
The Cortex-M3 processor core and the memory subsystem are not clocked in Deep-Sleep mode.
Peripherals are clocked that are enabled in the DCGCn registers when auto-clock gating is enabled
(see the RCC register) or the RCGCn registers when auto-clock gating is disabled. The system
clock source is specified in the DSLPCLKCFG register. When the DSLPCLKCFG register is used,
the internal oscillator source is powered up, if necessary, and other clocks are powered down. If
the PLL is running at the time of the WFI instruction, hardware powers the PLL down and overrides
the SYSDIV field of the active RCC/RCC2 register, to be determined by the DSDIVORIDE setting
in the DSLPCLKCFG register, up to /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. If the
PIOSC is used as the PLL reference clock source, it may continue to provide the clock during
Deep-Sleep. See page 237.
5.3
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, thereby configuring the microcontroller to run off a "raw" clock source
and allowing 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.
5.4
Register Map
Table 5-8 on page 211 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. Software should not modify any reserved memory address.
Additional Flash and ROM registers defined in the System Control register space are
described in the “Internal Memory” on page 301.
Table 5-8. System Control Register Map
Description
See
page
Offset
Name
Type
Reset
0x000
DID0
RO
-
Device Identification 0
214
0x004
DID1
RO
-
Device Identification 1
242
July 03, 2014
211
Texas Instruments-Production Data
System Control
Table 5-8. System Control Register Map (continued)
Offset
Name
0x008
Description
See
page
Type
Reset
DC0
RO
0x00FF.003F
Device Capabilities 0
244
0x010
DC1
RO
-
Device Capabilities 1
245
0x014
DC2
RO
0x570F.5337
Device Capabilities 2
248
0x018
DC3
RO
0xBFFF.FFFF
Device Capabilities 3
250
0x01C
DC4
RO
0x0004.F1FF
Device Capabilities 4
253
0x020
DC5
RO
0x0F30.00FF
Device Capabilities 5
255
0x024
DC6
RO
0x0000.0013
Device Capabilities 6
257
0x028
DC7
RO
0xFFFF.FFFF
Device Capabilities 7
258
0x02C
DC8
RO
0xFFFF.FFFF
Device Capabilities 8 ADC Channels
262
0x030
PBORCTL
R/W
0x0000.7FFD
Brown-Out Reset Control
216
0x040
SRCR0
R/W
0x00000000
Software Reset Control 0
294
0x044
SRCR1
R/W
0x00000000
Software Reset Control 1
296
0x048
SRCR2
R/W
0x00000000
Software Reset Control 2
299
0x050
RIS
RO
0x0000.0000
Raw Interrupt Status
217
0x054
IMC
R/W
0x0000.0000
Interrupt Mask Control
219
0x058
MISC
R/W1C
0x0000.0000
Masked Interrupt Status and Clear
221
0x05C
RESC
R/W
-
Reset Cause
223
0x060
RCC
R/W
0x078E.3AD1
Run-Mode Clock Configuration
225
0x064
PLLCFG
RO
-
XTAL to PLL Translation
230
0x06C
GPIOHBCTL
R/W
0x0000.0000
GPIO High-Performance Bus Control
231
0x070
RCC2
R/W
0x07C0.6810
Run-Mode Clock Configuration 2
233
0x07C
MOSCCTL
R/W
0x0000.0000
Main Oscillator Control
236
0x100
RCGC0
R/W
0x00000040
Run Mode Clock Gating Control Register 0
268
0x104
RCGC1
R/W
0x00000000
Run Mode Clock Gating Control Register 1
276
0x108
RCGC2
R/W
0x00000000
Run Mode Clock Gating Control Register 2
288
0x110
SCGC0
R/W
0x00000040
Sleep Mode Clock Gating Control Register 0
271
0x114
SCGC1
R/W
0x00000000
Sleep Mode Clock Gating Control Register 1
280
0x118
SCGC2
R/W
0x00000000
Sleep Mode Clock Gating Control Register 2
290
0x120
DCGC0
R/W
0x00000040
Deep Sleep Mode Clock Gating Control Register 0
274
0x124
DCGC1
R/W
0x00000000
Deep-Sleep Mode Clock Gating Control Register 1
284
0x128
DCGC2
R/W
0x00000000
Deep Sleep Mode Clock Gating Control Register 2
292
0x144
DSLPCLKCFG
R/W
0x0780.0000
Deep Sleep Clock Configuration
237
212
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 5-8. System Control Register Map (continued)
Name
Type
Reset
0x150
PIOSCCAL
R/W
0x0000.0000
Precision Internal Oscillator Calibration
239
0x170
I2SMCLKCFG
R/W
0x0000.0000
I2S MCLK Configuration
240
0x190
DC9
RO
0x00FF.00FF
Device Capabilities 9 ADC Digital Comparators
265
0x1A0
NVMSTAT
RO
0x0000.0001
Non-Volatile Memory Information
267
5.5
Description
See
page
Offset
Register Descriptions
All addresses given are relative to the System Control base address of 0x400F.E000.
July 03, 2014
213
Texas Instruments-Production Data
System Control
Register 1: Device Identification 0 (DID0), offset 0x000
This register identifies the version of the microcontroller. Each microcontroller is uniquely identified
by the combined values of the CLASS field in the DID0 register and the PARTNO field in the DID1
register.
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
1
RO
0
RO
0
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
31
reserved
RO
0
30:28
VER
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.
DID0 Version
This field defines the DID0 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
Second version of the DID0 register format.
27:24
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.
23:16
CLASS
RO
0x04
Device Class
The CLASS field value identifies the internal design from which all mask
sets are generated for all microcontrollers 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 microcontrollers.
The value of the CLASS field is encoded as follows (all other encodings
are reserved):
Value Description
0x04 Stellaris® Tempest-class microcontrollers
214
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
15:8
MAJOR
RO
-
Description
Major Revision
This field specifies the major revision number of the microcontroller.
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
0x0
Revision A (initial device)
0x1
Revision B (first base layer revision)
0x2
Revision C (second base layer revision)
and so on.
7:0
MINOR
RO
-
Minor Revision
This field specifies the minor revision number of the microcontroller.
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
0x0
Initial device, or a major revision update.
0x1
First metal layer change.
0x2
Second metal layer change.
and so on.
July 03, 2014
215
Texas Instruments-Production Data
System Control
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
Value Description
0
reserved
RO
0
0
A Brown Out Event causes an interrupt to be generated to the
interrupt controller.
1
A Brown Out Event causes a reset of the microcontroller.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
216
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 3: Raw Interrupt Status (RIS), offset 0x050
This register indicates the status for system control raw interrupts. An interrupt is sent to the interrupt
controller if the corresponding bit in the Interrupt Mask Control (IMC) register is set. Writing a 1
to the corresponding bit in the Masked Interrupt Status and Clear (MISC) register clears an interrupt
status bit.
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
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
BORRIS
reserved
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
MOSCPUPRIS USBPLLLRIS
Bit/Field
Name
Type
Reset
31:9
reserved
RO
0x0000.00
8
MOSCPUPRIS
RO
0
RO
0
RO
0
PLLLRIS
RO
0
reserved
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.
MOSC Power Up Raw Interrupt Status
Value Description
1
Sufficient time has passed for the MOSC to reach the expected
frequency. The value for this power-up time is indicated by
TMOSC_START.
0
Sufficient time has not passed for the MOSC to reach the
expected frequency.
This bit is cleared by writing a 1 to the MOSCPUPMIS bit in the MISC
register.
7
USBPLLLRIS
RO
0
USB PLL Lock Raw Interrupt Status
Value Description
1
The USB PLL timer has reached TREADY indicating that sufficient
time has passed for the USB PLL to lock.
0
The USB PLL timer has not reached TREADY.
This bit is cleared by writing a 1 to the USBPLLLMIS bit in the MISC
register.
6
PLLLRIS
RO
0
PLL Lock Raw Interrupt Status
Value Description
1
The PLL timer has reached TREADY indicating that sufficient time
has passed for the PLL to lock.
0
The PLL timer has not reached TREADY.
This bit is cleared by writing a 1 to the PLLLMIS bit in the MISC register.
July 03, 2014
217
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
5:2
reserved
RO
0x0
1
BORRIS
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.
Brown-Out Reset Raw Interrupt Status
Value Description
1
A brown-out condition is currently active.
0
A brown-out condition is not currently active.
Note the BORIOR bit in the PBORCTL register must be cleared to cause
an interrupt due to a Brown Out Event.
This bit is cleared by writing a 1 to the BORMIS bit in the MISC register.
0
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
218
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 4: Interrupt Mask Control (IMC), offset 0x054
This register contains the mask bits for system control raw interrupts. A raw interrupt, indicated by
a bit being set in the Raw Interrupt Status (RIS) register, is sent to the interrupt controller if the
corresponding bit in this register is set.
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
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
BORIM
reserved
RO
0
RO
0
RO
0
RO
0
R/W
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
MOSCPUPIM USBPLLLIM
Bit/Field
Name
Type
Reset
31:9
reserved
RO
0x0000.00
8
MOSCPUPIM
R/W
0
R/W
0
R/W
0
PLLLIM
R/W
0
reserved
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.
MOSC Power Up Interrupt Mask
Value Description
7
USBPLLLIM
R/W
0
1
An interrupt is sent to the interrupt controller when the
MOSCPUPRIS bit in the RIS register is set.
0
The MOSCPUPRIS interrupt is suppressed and not sent to the
interrupt controller.
USB PLL Lock Interrupt Mask
Value Description
6
PLLLIM
R/W
0
1
An interrupt is sent to the interrupt controller when the
USBPLLLRIS bit in the RIS register is set.
0
The USBPLLLRIS interrupt is suppressed and not sent to the
interrupt controller.
PLL Lock Interrupt Mask
Value Description
5:2
reserved
RO
0x0
1
An interrupt is sent to the interrupt controller when the PLLLRIS
bit in the RIS register is set.
0
The PLLLRIS interrupt is suppressed and not sent to the
interrupt controller.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
July 03, 2014
219
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
1
BORIM
R/W
0
Description
Brown-Out Reset Interrupt Mask
Value Description
0
reserved
RO
0
1
An interrupt is sent to the interrupt controller when the BORRIS
bit in the RIS register is set.
0
The BORRIS interrupt is suppressed and not sent to the interrupt
controller.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
220
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 5: Masked Interrupt Status and Clear (MISC), offset 0x058
On a read, this register gives the current masked status value of the corresponding interrupt in the
Raw Interrupt Status (RIS) register. All of the bits are R/W1C, thus writing a 1 to a bit clears the
corresponding raw interrupt bit in the RIS register (see page 217).
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
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
reserved
Type
Reset
reserved
Type
Reset
RO
0
MOSCPUPMIS USBPLLLMIS
Bit/Field
Name
Type
Reset
31:9
reserved
RO
0x0000.00
8
MOSCPUPMIS
R/W1C
0
R/W1C
0
R/W1C
0
PLLLMIS
R/W1C
0
reserved
BORMIS reserved
R/W1C
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.
MOSC Power Up Masked Interrupt Status
Value Description
1
When read, a 1 indicates that an unmasked interrupt was
signaled because sufficient time has passed for the MOSC PLL
to lock.
Writing a 1 to this bit clears it and also the MOSCPUPRIS bit in
the RIS register.
0
When read, a 0 indicates that sufficient time has not passed for
the MOSC PLL to lock.
A write of 0 has no effect on the state of this bit.
7
USBPLLLMIS
R/W1C
0
USB PLL Lock Masked Interrupt Status
Value Description
1
When read, a 1 indicates that an unmasked interrupt was
signaled because sufficient time has passed for the USB PLL
to lock.
Writing a 1 to this bit clears it and also the USBPLLLRIS bit in
the RIS register.
0
When read, a 0 indicates that sufficient time has not passed for
the USB PLL to lock.
A write of 0 has no effect on the state of this bit.
July 03, 2014
221
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
6
PLLLMIS
R/W1C
0
Description
PLL Lock Masked Interrupt Status
Value Description
1
When read, a 1 indicates that an unmasked interrupt was
signaled because sufficient time has passed for the PLL to lock.
Writing a 1 to this bit clears it and also the PLLLRIS bit in the
RIS register.
0
When read, a 0 indicates that sufficient time has not passed for
the PLL to lock.
A write of 0 has no effect on the state of this bit.
5:2
reserved
RO
0x0
1
BORMIS
R/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.
BOR Masked Interrupt Status
Value Description
1
When read, a 1 indicates that an unmasked interrupt was
signaled because of a brown-out condition.
Writing a 1 to this bit clears it and also the BORRIS bit in the
RIS register.
0
When read, a 0 indicates that a brown-out condition has not
occurred.
A write of 0 has no effect on the state of this bit.
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.
222
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 6: 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 a power- on reset or an external reset is
the cause, in which case, all bits other than POR or EXT 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
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
RO
0
RO
0
RO
0
RO
0
RO
0
24
23
22
21
20
19
18
17
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
-
9
8
7
6
5
4
3
2
1
0
WDT1
SW
WDT0
BOR
POR
EXT
RO
0
RO
0
RO
0
RO
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
reserved
Type
Reset
MOSCFAIL
reserved
Type
Reset
RO
0
16
Bit/Field
Name
Type
Reset
Description
31:17
reserved
RO
0x000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
16
MOSCFAIL
R/W
-
MOSC Failure Reset
Value Description
1
When read, this bit indicates that the MOSC circuit was enabled
for clock validation and failed, generating a reset event.
0
When read, this bit indicates that a MOSC failure has not
generated a reset since the previous power-on reset.
Writing a 0 to this bit clears it.
15:6
reserved
RO
0x00
5
WDT1
R/W
-
Software should not rely on the value of 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 Timer 1 Reset
Value Description
1
When read, this bit indicates that Watchdog Timer 1 timed out
and generated a reset.
0
When read, this bit indicates that Watchdog Timer 1 has not
generated a reset since the previous power-on reset.
Writing a 0 to this bit clears it.
July 03, 2014
223
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
4
SW
R/W
-
Description
Software Reset
Value Description
1
When read, this bit indicates that a software reset has caused
a reset event.
0
When read, this bit indicates that a software reset has not
generated a reset since the previous power-on reset.
Writing a 0 to this bit clears it.
3
WDT0
R/W
-
Watchdog Timer 0 Reset
Value Description
1
When read, this bit indicates that Watchdog Timer 0 timed out
and generated a reset.
0
When read, this bit indicates that Watchdog Timer 0 has not
generated a reset since the previous power-on reset.
Writing a 0 to this bit clears it.
2
BOR
R/W
-
Brown-Out Reset
Value Description
1
When read, this bit indicates that a brown-out reset has caused
a reset event.
0
When read, this bit indicates that a brown-out reset has not
generated a reset since the previous power-on reset.
Writing a 0 to this bit clears it.
1
POR
R/W
-
Power-On Reset
Value Description
1
When read, this bit indicates that a power-on reset has caused
a reset event.
0
When read, this bit indicates that a power-on reset has not
generated a reset.
Writing a 0 to this bit clears it.
0
EXT
R/W
-
External Reset
Value Description
1
When read, this bit indicates that an external reset (RST
assertion) has caused a reset event.
0
When read, this bit indicates that an external reset (RST
assertion) has not caused a reset event since the previous
power-on reset.
Writing a 0 to this bit clears it.
224
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 7: Run-Mode Clock Configuration (RCC), offset 0x060
The bits in this register configure the system clock and oscillators.
Important: Write the RCC register prior to writing the RCC2 register. If a subsequent write to the
RCC register is required, include another register access after writing the RCC register
and before writing the RCC2 register.
Run-Mode Clock Configuration (RCC)
Base 0x400F.E000
Offset 0x060
Type R/W, reset 0x078E.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
0
27
26
25
24
23
R/W
0
R/W
1
R/W
1
R/W
1
R/W
1
11
10
9
8
R/W
0
R/W
1
ACG
PWRDN
RO
1
21
20
USESYSDIV
reserved
USEPWMDIV
R/W
0
RO
0
R/W
0
R/W
1
R/W
1
R/W
1
RO
0
7
6
5
4
3
2
1
0
R/W
1
R/W
1
R/W
0
R/W
1
RO
0
SYSDIV
reserved BYPASS
R/W
1
22
XTAL
R/W
1
Bit/Field
Name
Type
Reset
31:28
reserved
RO
0x0
27
ACG
R/W
0
R/W
0
OSCSRC
19
18
17
PWMDIV
reserved
RO
0
16
reserved
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 microcontroller enters a Sleep
or Deep-Sleep mode (respectively).
Value Description
1
The SCGCn or DCGCn registers are used to control the clocks
distributed to the peripherals when the microcontroller is in a
sleep mode. The SCGCn and DCGCn registers allow unused
peripherals to consume less power when the microcontroller is
in a sleep mode.
0
The Run-Mode Clock Gating Control (RCGCn) registers are
used when the microcontroller enters a sleep mode.
The RCGCn registers are always used to control the clocks in Run
mode.
26:23
SYSDIV
R/W
0xF
System Clock Divisor
Specifies which divisor is used to generate the system clock from either
the PLL output or the oscillator source (depending on how the BYPASS
bit in this register is configured). See Table 5-5 on page 206 for bit
encodings.
If the SYSDIV value is less than MINSYSDIV (see page 245), and the
PLL is being used, then the MINSYSDIV value is used as the divisor.
If the PLL is not being used, the SYSDIV value can be less than
MINSYSDIV.
July 03, 2014
225
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
22
USESYSDIV
R/W
0
Description
Enable System Clock Divider
Value Description
1
The system clock divider is the source for the system clock. The
system clock divider is forced to be used when the PLL is
selected as the source.
If the USERCC2 bit in the RCC2 register is set, then the SYSDIV2
field in the RCC2 register is used as the system clock divider
rather than the SYSDIV field in this register.
0
The system clock is used undivided.
21
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
20
USEPWMDIV
R/W
0
Enable PWM Clock Divisor
Value Description
1
The PWM clock divider is the source for the PWM clock.
0
The system clock is the source for the PWM clock.
Note that when the PWM divisor is used, it is applied to the clock for
both PWM modules.
19:17
PWMDIV
R/W
0x7
PWM Unit Clock Divisor
This field specifies the binary divisor used to predivide the system clock
down for use as the timing reference for the PWM module. The rising
edge of this clock is synchronous with the system clock.
Value Divisor
16:14
reserved
RO
0x0
13
PWRDN
R/W
1
0x0
/2
0x1
/4
0x2
/8
0x3
/16
0x4
/32
0x5
/64
0x6
/64
0x7
/64 (default)
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
PLL Power Down
Value Description
1
The PLL is powered down. Care must be taken to ensure that
another clock source is functioning and that the BYPASS bit is
set before setting this bit.
0
The PLL is operating normally.
226
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
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.
11
BYPASS
R/W
1
PLL Bypass
Value Description
1
The system clock is derived from the OSC source and divided
by the divisor specified by SYSDIV.
0
The system clock is the PLL output clock divided by the divisor
specified by SYSDIV.
See Table 5-5 on page 206 for programming guidelines.
Note:
The ADC must be clocked from the PLL or directly from a
16-MHz clock source to operate properly.
July 03, 2014
227
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
Description
10:6
XTAL
R/W
0x0B
Crystal Value
This field specifies the crystal value attached to the main oscillator. The
encoding for this field is provided below. Depending on the crystal used,
the PLL frequency may not be exactly 400 MHz, see Table
25-8 on page 1253 for more information.
Frequencies that may be used with the USB interface are indicated in
the table. To function within the clocking requirements of the USB
specification, a crystal of 4, 5, 6, 8, 10, 12, or 16 MHz must be used.
Value Crystal Frequency (MHz) Not Crystal Frequency (MHz) Using
Using the PLL
the PLL
0x00
1.000 MHz
reserved
0x01
1.8432 MHz
reserved
0x02
2.000 MHz
reserved
0x03
2.4576 MHz
0x04
reserved
3.579545 MHz
0x05
3.6864 MHz
0x06
4 MHz (USB)
0x07
4.096 MHz
0x08
4.9152 MHz
0x09
5 MHz (USB)
0x0A
5.12 MHz
0x0B
6 MHz (reset value)(USB)
0x0C
6.144 MHz
0x0D
7.3728 MHz
0x0E
8 MHz (USB)
0x0F
8.192 MHz
0x10
10.0 MHz (USB)
0x11
12.0 MHz (USB)
0x12
12.288 MHz
0x13
13.56 MHz
0x14
14.31818 MHz
0x15
16.0 MHz (USB)
0x16
16.384 MHz
228
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
5:4
OSCSRC
R/W
0x1
Description
Oscillator Source
Selects the input source for the OSC. The values are:
Value Input Source
0x0
MOSC
Main oscillator
0x1
PIOSC
Precision internal oscillator
(default)
0x2
PIOSC/4
Precision internal oscillator / 4
0x3
30 kHz
30-kHz internal oscillator
For additional oscillator sources, see the RCC2 register.
3:2
reserved
RO
0x0
1
IOSCDIS
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.
Precision Internal Oscillator Disable
Value Description
0
MOSCDIS
R/W
1
1
The precision internal oscillator (PIOSC) is disabled.
0
The precision internal oscillator is enabled.
Main Oscillator Disable
Value Description
1
The main oscillator is disabled (default).
0
The main oscillator is enabled.
July 03, 2014
229
Texas Instruments-Production Data
System Control
Register 8: 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 225).
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
-
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
reserved
Type
Reset
RO
0
RO
0
F
Bit/Field
Name
Type
Reset
31:14
reserved
RO
0x0000.0
13:5
F
RO
-
R
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.
PLL F Value
This field specifies the value supplied to the PLL’s F input.
4:0
R
RO
-
PLL R Value
This field specifies the value supplied to the PLL’s R input.
230
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 9: GPIO High-Performance Bus Control (GPIOHBCTL), offset 0x06C
This register controls which internal bus is used to access each GPIO port. When a bit is clear, the
corresponding GPIO port is accessed across the legacy Advanced Peripheral Bus (APB) bus and
through the APB memory aperture. When a bit is set, the corresponding port is accessed across
the Advanced High-Performance Bus (AHB) bus and through the AHB memory aperture. Each
GPIO port can be individually configured to use AHB or APB, but may be accessed only through
one aperture. The AHB bus provides better back-to-back access performance than the APB bus.
The address aperture in the memory map changes for the ports that are enabled for AHB access
(see Table 8-7 on page 409).
GPIO High-Performance Bus Control (GPIOHBCTL)
Base 0x400F.E000
Offset 0x06C
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
PORTJ
PORTH
PORTG
PORTF
PORTE
PORTD
PORTC
PORTB
PORTA
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
reserved
Type
Reset
RO
0
Bit/Field
Name
Type
Reset
31:9
reserved
RO
0x0000.0
8
PORTJ
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.
Port J Advanced High-Performance Bus
This bit defines the memory aperture for Port J.
Value Description
7
PORTH
R/W
0
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
Port H Advanced High-Performance Bus
This bit defines the memory aperture for Port H.
Value Description
6
PORTG
R/W
0
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
Port G Advanced High-Performance Bus
This bit defines the memory aperture for Port G.
Value Description
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
July 03, 2014
231
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
5
PORTF
R/W
0
Description
Port F Advanced High-Performance Bus
This bit defines the memory aperture for Port F.
Value Description
4
PORTE
R/W
0
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
Port E Advanced High-Performance Bus
This bit defines the memory aperture for Port E.
Value Description
3
PORTD
R/W
0
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
Port D Advanced High-Performance Bus
This bit defines the memory aperture for Port D.
Value Description
2
PORTC
R/W
0
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
Port C Advanced High-Performance Bus
This bit defines the memory aperture for Port C.
Value Description
1
PORTB
R/W
0
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
Port B Advanced High-Performance Bus
This bit defines the memory aperture for Port B.
Value Description
0
PORTA
R/W
0
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
Port A Advanced High-Performance Bus
This bit defines the memory aperture for Port A.
Value Description
1
Advanced High-Performance Bus (AHB)
0
Advanced Peripheral Bus (APB). This bus is the legacy bus.
232
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 10: Run-Mode Clock Configuration 2 (RCC2), offset 0x070
This register overrides the RCC equivalent register fields, as shown in Table 5-9, when the USERCC2
bit is set, allowing the extended capabilities of the RCC2 register to be used while also providing a
means to be backward-compatible to previous parts. Each RCC2 field that supersedes an RCC
field is located at the same LSB bit position; however, some RCC2 fields are larger than the
corresponding RCC field.
Table 5-9. RCC2 Fields that Override RCC Fields
RCC2 Field...
Overrides RCC Field
SYSDIV2, bits[28:23]
SYSDIV, bits[26:23]
PWRDN2, bit[13]
PWRDN, bit[13]
BYPASS2, bit[11]
BYPASS, bit[11]
OSCSRC2, bits[6:4]
OSCSRC, bits[5:4]
Important: Write the RCC register prior to writing the RCC2 register. If a subsequent write to the
RCC register is required, include another register access after writing the RCC register
and before writing the RCC2 register.
Run-Mode Clock Configuration 2 (RCC2)
Base 0x400F.E000
Offset 0x070
Type R/W, reset 0x07C0.6810
31
30
USERCC2 DIV400
Type
Reset
29
28
27
26
reserved
25
23
22
R/W
0
R/W
0
RO
0
R/W
0
R/W
0
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
RO
0
R/W
1
R/W
1
RO
0
reserved
R/W
1
RO
0
21
20
19
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31
USERCC2
R/W
0
Use RCC2
R/W
0
17
16
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
18
reserved
SYSDIV2LSB
reserved USBPWRDN PWRDN2 reserved BYPASS2
Type
Reset
24
SYSDIV2
R/W
0
reserved
R/W
1
RO
0
RO
0
Value Description
30
DIV400
R/W
0
1
The RCC2 register fields override the RCC register fields.
0
The RCC register fields are used, and the fields in RCC2 are
ignored.
Divide PLL as 400 MHz vs. 200 MHz
This bit, along with the SYSDIV2LSB bit, allows additional frequency
choices.
Value Description
1
Append the SYSDIV2LSB bit to the SYSDIV2 field to create a
7 bit divisor using the 400 MHz PLL output, see Table
5-7 on page 207.
0
Use SYSDIV2 as is and apply to 200 MHz predivided PLL
output. See Table 5-6 on page 206 for programming guidelines.
July 03, 2014
233
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
29
reserved
RO
0x0
28:23
SYSDIV2
R/W
0x0F
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.
System Clock Divisor 2
Specifies which divisor is used to generate the system clock from either
the PLL output or the oscillator source (depending on how the BYPASS2
bit is configured). SYSDIV2 is used for the divisor when both the
USESYSDIV bit in the RCC register and the USERCC2 bit in this register
are set. See Table 5-6 on page 206 for programming guidelines.
22
SYSDIV2LSB
R/W
1
Additional LSB for SYSDIV2
When DIV400 is set, this bit becomes the LSB of SYSDIV2. If DIV400
is clear, this bit is not used. See Table 5-6 on page 206 for programming
guidelines.
This bit can only be set or cleared when DIV400 is set.
21:15
reserved
RO
0x0
14
USBPWRDN
R/W
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.
Power-Down USB PLL
Value Description
13
PWRDN2
R/W
1
1
The USB PLL is powered down.
0
The USB PLL operates normally.
Power-Down PLL 2
Value Description
1
The PLL is powered down.
0
The PLL operates normally.
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
PLL Bypass 2
Value Description
1
The system clock is derived from the OSC source and divided
by the divisor specified by SYSDIV2.
0
The system clock is the PLL output clock divided by the divisor
specified by SYSDIV2.
See Table 5-6 on page 206 for programming guidelines.
Note:
10:7
reserved
RO
0x0
The ADC must be clocked from the PLL or directly from a
16-MHz clock source to operate properly.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
234
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
6:4
OSCSRC2
R/W
0x1
Description
Oscillator Source 2
Selects the input source for the OSC. The values are:
Value
Description
0x0
MOSC
Main oscillator
0x1
PIOSC
Precision internal oscillator
0x2
PIOSC/4
Precision internal oscillator / 4
0x3
30 kHz
30-kHz internal oscillator
0x4-0x7 Reserved
3:0
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.
July 03, 2014
235
Texas Instruments-Production Data
System Control
Register 11: Main Oscillator Control (MOSCCTL), offset 0x07C
This register provides the ability to enable the MOSC clock verification circuit. When enabled, this
circuit monitors the frequency of the MOSC to verify that the oscillator is operating within specified
limits. If the clock goes invalid after being enabled, the microcontroller issues a power-on reset and
reboots to the NMI handler.
Main Oscillator Control (MOSCCTL)
Base 0x400F.E000
Offset 0x07C
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
Bit/Field
Name
Type
Reset
31:1
reserved
RO
0x0000.000
0
CVAL
R/W
0
RO
0
CVAL
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.
Clock Validation for MOSC
Value Description
1
The MOSC monitor circuit is enabled.
0
The MOSC monitor circuit is disabled.
236
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 12: 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
DSOSCSRC
RO
0
Bit/Field
Name
Type
Reset
31:29
reserved
RO
0x0
28:23
DSDIVORIDE
R/W
0x0F
R/W
0
reserved
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.
Divider Field Override
If Deep-Sleep mode is enabled when the PLL is running, the PLL is
disabled. This 6-bit field contains a system divider field that overrides
the SYSDIV field in the RCC register or the SYSDIV2 field in the RCC2
register during Deep Sleep. This divider is applied to the source selected
by the DSOSCSRC field.
Value Description
0x0
/1
0x1
/2
0x2
/3
0x3
/4
...
...
0x3F /64
22:7
reserved
RO
0x000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
July 03, 2014
237
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
6:4
DSOSCSRC
R/W
0x0
Description
Clock Source
Specifies the clock source during Deep-Sleep mode.
Value
Description
0x0
MOSC
Use the main oscillator as the source.
Note:
0x1
If the PIOSC is being used as the clock reference
for the PLL, the PIOSC is the clock source instead
of MOSC in Deep-Sleep mode.
PIOSC
Use the precision internal 16-MHz oscillator as the source.
0x2
Reserved
0x3
30 kHz
Use the 30-kHz internal oscillator as the source.
0x4-0x7 Reserved
3:0
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.
238
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 13: Precision Internal Oscillator Calibration (PIOSCCAL), offset 0x150
This register provides the ability to update or recalibrate the precision internal oscillator.
Precision Internal Oscillator Calibration (PIOSCCAL)
Base 0x400F.E000
Offset 0x150
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
R/W
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
UTEN
Type
Reset
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
reserved
reserved
Type
Reset
23
RO
0
UPDATE reserved
Bit/Field
Name
Type
Reset
31
UTEN
R/W
0
R/W
0
RO
0
UT
Description
Use User Trim Value
Value Description
30:9
reserved
RO
0x0000
8
UPDATE
R/W
0
1
The trim value in bits[6:0] of this register are used for any update
trim operation.
0
The factory calibration value is used for an update trim operation.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Update Trim
Value Description
1
Updates the PIOSC trim value with the UT bit. Used with UTEN.
0
No action.
This bit is auto-cleared after the update.
7
reserved
RO
0
6:0
UT
R/W
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.
User Trim Value
User trim value that can be loaded into the PIOSC.
Refer to “Main PLL Frequency Configuration” on page 208 for more
information on calibrating the PIOSC.
July 03, 2014
239
Texas Instruments-Production Data
System Control
Register 14: I2S MCLK Configuration (I2SMCLKCFG), offset 0x170
This register configures the receive and transmit fractional clock dividers for the for the I2S master
transmit and receive clocks (I2S0TXMCLK and I2S0RXMCLK). Varying the integer and fractional
inputs for the clocks allows greater accuracy in hitting the target I2S clock frequencies. Refer to
“Clock Control” on page 827 for combinations of the TXI and TXF bits and the RXI and RXF bits that
provide MCLK frequencies within acceptable error limits.
I2S MCLK Configuration (I2SMCLKCFG)
Base 0x400F.E000
Offset 0x170
Type R/W, reset 0x0000.0000
Type
Reset
Type
Reset
31
30
RXEN
reserved
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
13
12
11
10
9
15
14
TXEN
reserved
R/W
0
RO
0
29
28
27
26
25
24
23
22
21
20
19
18
RXI
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
8
7
6
5
4
3
2
TXI
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
31
RXEN
R/W
0
17
16
R/W
0
R/W
0
1
0
R/W
0
R/W
0
RXF
TXF
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Description
RX Clock Enable
Value Description
1
The I2S receive clock generator is enabled.
0
The I2S receive clock generator is disabled.
If the RXSLV bit in the I2S Module Configuration (I2SCFG)
register is set, then the I2S0RXMCLK must be externally
generated.
30
reserved
RO
0
29:20
RXI
R/W
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.
RX Clock Integer Input
This field contains the integer input for the receive clock generator.
19:16
RXF
R/W
0x0
RX Clock Fractional Input
This field contains the fractional input for the receive clock generator.
15
TXEN
R/W
0
TX Clock Enable
Value Description
1
The I2S transmit clock generator is enabled.
0
The I2S transmit clock generator is disabled.
If the TXSLV bit in the I2S Module Configuration (I2SCFG)
register is set, then the I2S0TXMCLK must be externally
generated.
240
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
14
reserved
RO
0
13:4
TXI
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.
TX Clock Integer Input
This field contains the integer input for the transmit clock generator.
3:0
TXF
R/W
0x0
TX Clock Fractional Input
This field contains the fractional input for the transmit clock generator.
July 03, 2014
241
Texas Instruments-Production Data
System Control
Register 15: Device Identification 1 (DID1), offset 0x004
This register identifies the device family, part number, temperature range, pin count, and package
type. Each microcontroller is uniquely identified by the combined values of the CLASS field in the
DID0 register and the PARTNO field in the DID1 register.
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
0
RO
1
RO
1
RO
0
14
13
12
11
10
9
8
7
6
5
4
RO
0
RO
0
RO
0
RO
0
RO
0
RO
-
RO
-
RO
-
VER
Type
Reset
FAM
PINCOUNT
Type
Reset
RO
0
RO
1
18
17
16
RO
1
RO
0
RO
0
RO
1
3
2
1
0
PARTNO
reserved
RO
0
19
TEMP
Bit/Field
Name
Type
Reset
31:28
VER
RO
0x1
RO
-
PKG
ROHS
RO
-
RO
1
QUAL
RO
-
RO
-
Description
DID1 Version
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
Second version of the DID1 register format.
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
0x69
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
0x69 LM3S5791
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
242
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
12:8
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.
7:5
TEMP
RO
-
Temperature Range
This field specifies the temperature rating of the device. The value is
encoded as follows (all other encodings are reserved):
Value Description
4:3
PKG
RO
-
0x0
Commercial temperature range (0°C to 70°C)
0x1
Industrial temperature range (-40°C to 85°C)
0x2
Extended temperature range (-40°C to 105°C)
Package Type
This field specifies the package type. The value is encoded as follows
(all other encodings are reserved):
Value Description
2
ROHS
RO
1
0x0
SOIC package
0x1
LQFP package
0x2
BGA 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
July 03, 2014
243
Texas Instruments-Production Data
System Control
Register 16: 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.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
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
0
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
0x003F
Flash Size
Indicates the size of the on-chip flash memory.
Value
Description
0x003F 128 KB of Flash
244
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 17: Device Capabilities 1 (DC1), offset 0x010
This register is predefined by the part and can be used to verify features. If any bit is clear in this
register, the module is not present. The corresponding bit in the RCGC0, SCGC0, and DCGC0
registers cannot be set.
Device Capabilities 1 (DC1)
Base 0x400F.E000
Offset 0x010
Type RO, reset 31
30
29
reserved
Type
Reset
28
WDT1
26
24
23
22
21
19
16
CAN1
CAN0
ADC1
ADC0
RO
0
RO
0
RO
1
RO
1
RO
0
RO
0
RO
0
RO
1
RO
0
RO
0
RO
1
RO
1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PLL
WDT0
SWO
SWD
JTAG
RO
-
RO
-
RO
1
RO
1
RO
1
RO
1
RO
1
MAXADC0SPD
RO
1
RO
1
RO
1
RO
1
MPU
RO
1
reserved TEMPSNS
RO
0
RO
1
reserved
17
RO
1
MAXADC1SPD
PWM
18
RO
0
RO
-
reserved
20
RO
0
RO
-
reserved
25
RO
0
MINSYSDIV
Type
Reset
27
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
WDT1
RO
1
Watchdog Timer 1 Present
When set, indicates that watchdog timer 1 is present.
27:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
CAN1
RO
1
CAN Module 1 Present
When set, indicates that CAN unit 1 is present.
24
CAN0
RO
1
CAN Module 0 Present
When set, indicates that CAN unit 0 is present.
23:21
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
20
PWM
RO
1
PWM Module Present
When set, indicates that the PWM module is present.
19:18
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
17
ADC1
RO
1
ADC Module 1 Present
When set, indicates that ADC module 1 is present.
16
ADC0
RO
1
ADC Module 0 Present
When set, indicates that ADC module 0 is present
July 03, 2014
245
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
15:12
MINSYSDIV
RO
-
Description
System Clock Divider
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
11:10
MAXADC1SPD
RO
0x3
0x1
Specifies an 80-MHz CPU clock with a PLL divider of 2.5.
0x2
Specifies a 66.67-MHz CPU clock with a PLL divider of 3.
0x3
Specifies a 50-MHz CPU clock with a PLL divider of 4.
0x7
Specifies a 25-MHz clock with a PLL divider of 8.
0x9
Specifies a 20-MHz clock with a PLL divider of 10.
Max ADC1 Speed
This field indicates the maximum rate at which the ADC samples data.
Value Description
0x3
9:8
MAXADC0SPD
RO
0x3
1M samples/second
Max ADC0 Speed
This field indicates the maximum rate at which the ADC samples data.
Value Description
0x3
7
MPU
RO
1
1M samples/second
MPU Present
When set, indicates that the Cortex-M3 Memory Protection Unit (MPU)
module is present. See the "Cortex-M3 Peripherals" chapter for details
on the MPU.
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
TEMPSNS
RO
1
Temp Sensor Present
When set, indicates that the on-chip temperature sensor is present.
4
PLL
RO
1
PLL Present
When set, indicates that the on-chip Phase Locked Loop (PLL) is
present.
3
WDT0
RO
1
Watchdog Timer 0 Present
When set, indicates that watchdog timer 0 is present.
2
SWO
RO
1
SWO Trace Port Present
When set, indicates that the Serial Wire Output (SWO) trace port is
present.
1
SWD
RO
1
SWD Present
When set, indicates that the Serial Wire Debugger (SWD) is present.
246
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
0
JTAG
RO
1
Description
JTAG Present
When set, indicates that the JTAG debugger interface is present.
July 03, 2014
247
Texas Instruments-Production Data
System Control
Register 18: Device Capabilities 2 (DC2), offset 0x014
This register is predefined by the part and can be used to verify features. If any bit is clear in this
register, the module is not present. The corresponding bit in the RCGC0, SCGC0, and DCGC0
registers cannot be set.
Device Capabilities 2 (DC2)
Base 0x400F.E000
Offset 0x014
Type RO, reset 0x570F.5337
Type
Reset
Type
Reset
31
30
29
28
27
26
25
24
reserved
EPI0
reserved
I2S0
reserved
COMP2
COMP1
COMP0
RO
0
RO
1
RO
0
RO
1
RO
0
RO
1
RO
1
15
14
13
12
11
10
reserved
I2C1
reserved
I2C0
RO
0
RO
1
RO
0
RO
1
reserved
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
1
RO
0
RO
0
RO
0
RO
0
TIMER3
TIMER2
TIMER1
TIMER0
RO
1
RO
1
RO
1
RO
1
9
8
7
6
5
4
3
2
1
0
QEI1
QEI0
RO
1
RO
1
SSI1
SSI0
reserved
UART2
UART1
UART0
RO
1
RO
1
RO
0
RO
1
RO
1
RO
1
reserved
reserved
RO
0
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
EPI0
RO
1
EPI Module 0 Present
When set, indicates that EPI 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
I2S0
RO
1
I2S Module 0 Present
When set, indicates that I2S module 0 is present.
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
Analog Comparator 2 Present
When set, indicates that analog comparator 2 is present.
25
COMP1
RO
1
Analog Comparator 1 Present
When set, indicates that analog comparator 1 is present.
24
COMP0
RO
1
Analog Comparator 0 Present
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
Timer Module 3 Present
When set, indicates that General-Purpose Timer module 3 is present.
18
TIMER2
RO
1
Timer Module 2 Present
When set, indicates that General-Purpose Timer module 2 is present.
248
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
17
TIMER1
RO
1
Description
Timer Module 1 Present
When set, indicates that General-Purpose Timer module 1 is present.
16
TIMER0
RO
1
Timer Module 0 Present
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
I2C Module 1 Present
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
I2C Module 0 Present
When set, indicates that I2C module 0 is present.
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
QEI1
RO
1
QEI Module 1 Present
When set, indicates that QEI module 1 is present.
8
QEI0
RO
1
QEI Module 0 Present
When set, indicates that QEI module 0 is present.
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
SSI1
RO
1
SSI Module 1 Present
When set, indicates that SSI module 1 is present.
4
SSI0
RO
1
SSI Module 0 Present
When set, indicates that SSI module 0 is present.
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
UART Module 2 Present
When set, indicates that UART module 2 is present.
1
UART1
RO
1
UART Module 1 Present
When set, indicates that UART module 1 is present.
0
UART0
RO
1
UART Module 0 Present
When set, indicates that UART module 0 is present.
July 03, 2014
249
Texas Instruments-Production Data
System Control
Register 19: Device Capabilities 3 (DC3), offset 0x018
This register is predefined by the part and can be used to verify features. If any bit is clear in this
register, the module is not present. The corresponding bit in the RCGC0, SCGC0, and DCGC0
registers cannot be set.
Device Capabilities 3 (DC3)
Base 0x400F.E000
Offset 0x018
Type RO, reset 0xBFFF.FFFF
Type
Reset
Type
Reset
31
30
29
28
27
26
25
24
32KHZ
reserved
CCP5
CCP4
CCP3
CCP2
CCP1
CCP0
RO
1
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
PWMFAULT
C2O
PWM5
PWM4
PWM3
PWM2
PWM1
PWM0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
C2PLUS C2MINUS
RO
1
RO
1
C1O
C1PLUS C1MINUS
RO
1
RO
1
RO
1
Bit/Field
Name
Type
Reset
31
32KHZ
RO
1
C0O
RO
1
23
22
21
20
19
18
17
16
ADC0AIN7 ADC0AIN6 ADC0AIN5 ADC0AIN4 ADC0AIN3 ADC0AIN2 ADC0AIN1 ADC0AIN0
C0PLUS C0MINUS
RO
1
RO
1
Description
32KHz Input Clock Available
When set, indicates an even CCP pin is present and can be used as a
32-KHz input clock.
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
CCP5 Pin Present
When set, indicates that Capture/Compare/PWM pin 5 is present.
28
CCP4
RO
1
CCP4 Pin Present
When set, indicates that Capture/Compare/PWM pin 4 is present.
27
CCP3
RO
1
CCP3 Pin Present
When set, indicates that Capture/Compare/PWM pin 3 is present.
26
CCP2
RO
1
CCP2 Pin Present
When set, indicates that Capture/Compare/PWM pin 2 is present.
25
CCP1
RO
1
CCP1 Pin Present
When set, indicates that Capture/Compare/PWM pin 1 is present.
24
CCP0
RO
1
CCP0 Pin Present
When set, indicates that Capture/Compare/PWM pin 0 is present.
23
ADC0AIN7
RO
1
ADC Module 0 AIN7 Pin Present
When set, indicates that ADC module 0 input pin 7 is present.
22
ADC0AIN6
RO
1
ADC Module 0 AIN6 Pin Present
When set, indicates that ADC module 0 input pin 6 is present.
21
ADC0AIN5
RO
1
ADC Module 0 AIN5 Pin Present
When set, indicates that ADC module 0 input pin 5 is present.
250
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
20
ADC0AIN4
RO
1
Description
ADC Module 0 AIN4 Pin Present
When set, indicates that ADC module 0 input pin 4 is present.
19
ADC0AIN3
RO
1
ADC Module 0 AIN3 Pin Present
When set, indicates that ADC module 0 input pin 3 is present.
18
ADC0AIN2
RO
1
ADC Module 0 AIN2 Pin Present
When set, indicates that ADC module 0 input pin 2 is present.
17
ADC0AIN1
RO
1
ADC Module 0 AIN1 Pin Present
When set, indicates that ADC module 0 input pin 1 is present.
16
ADC0AIN0
RO
1
ADC Module 0 AIN0 Pin Present
When set, indicates that ADC module 0 input pin 0 is present.
15
PWMFAULT
RO
1
PWM Fault Pin Present
When set, indicates that a PWM Fault pin is present. See DC5 for
specific Fault pins on this device.
14
C2O
RO
1
C2o Pin Present
When set, indicates that the analog comparator 2 output pin is present.
13
C2PLUS
RO
1
C2+ Pin Present
When set, indicates that the analog comparator 2 (+) input pin is present.
12
C2MINUS
RO
1
C2- Pin Present
When set, indicates that the analog comparator 2 (-) input pin is present.
11
C1O
RO
1
C1o Pin Present
When set, indicates that the analog comparator 1 output pin is present.
10
C1PLUS
RO
1
C1+ Pin Present
When set, indicates that the analog comparator 1 (+) input pin is present.
9
C1MINUS
RO
1
C1- Pin Present
When set, indicates that the analog comparator 1 (-) input pin is present.
8
C0O
RO
1
C0o Pin Present
When set, indicates that the analog comparator 0 output pin is present.
7
C0PLUS
RO
1
C0+ Pin Present
When set, indicates that the analog comparator 0 (+) input pin is present.
6
C0MINUS
RO
1
C0- Pin Present
When set, indicates that the analog comparator 0 (-) input pin is present.
5
PWM5
RO
1
PWM5 Pin Present
When set, indicates that the PWM pin 5 is present.
4
PWM4
RO
1
PWM4 Pin Present
When set, indicates that the PWM pin 4 is present.
3
PWM3
RO
1
PWM3 Pin Present
When set, indicates that the PWM pin 3 is present.
July 03, 2014
251
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
2
PWM2
RO
1
Description
PWM2 Pin Present
When set, indicates that the PWM pin 2 is present.
1
PWM1
RO
1
PWM1 Pin Present
When set, indicates that the PWM pin 1 is present.
0
PWM0
RO
1
PWM0 Pin Present
When set, indicates that the PWM pin 0 is present.
252
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 20: Device Capabilities 4 (DC4), offset 0x01C
This register is predefined by the part and can be used to verify features. If any bit is clear in this
register, the module is not present. The corresponding bit in the RCGC0, SCGC0, and DCGC0
registers cannot be set.
Device Capabilities 4 (DC4)
Base 0x400F.E000
Offset 0x01C
Type RO, reset 0x0004.F1FF
31
30
29
28
27
26
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
CCP7
CCP6
UDMA
ROM
RO
1
RO
1
RO
1
RO
1
25
24
23
22
21
20
19
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
0
RO
0
9
8
7
6
5
4
3
2
1
0
GPIOJ
GPIOH
GPIOG
GPIOF
GPIOE
GPIOD
GPIOC
GPIOB
GPIOA
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
reserved
Type
Reset
Type
Reset
reserved
RO
0
RO
0
RO
0
18
17
PICAL
16
reserved
Bit/Field
Name
Type
Reset
Description
31:19
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
PICAL
RO
1
PIOSC Calibrate
When set, indicates that the PIOSC can be calibrated.
17:16
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
CCP7
RO
1
CCP7 Pin Present
When set, indicates that Capture/Compare/PWM pin 7 is present.
14
CCP6
RO
1
CCP6 Pin Present
When set, indicates that Capture/Compare/PWM pin 6 is present.
13
UDMA
RO
1
Micro-DMA Module Present
When set, indicates that the micro-DMA module present.
12
ROM
RO
1
Internal Code ROM Present
When set, indicates that internal code ROM is present.
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
GPIOJ
RO
1
GPIO Port J Present
When set, indicates that GPIO Port J is present.
7
GPIOH
RO
1
GPIO Port H Present
When set, indicates that GPIO Port H is present.
6
GPIOG
RO
1
GPIO Port G Present
When set, indicates that GPIO Port G is present.
July 03, 2014
253
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
5
GPIOF
RO
1
Description
GPIO Port F Present
When set, indicates that GPIO Port F is present.
4
GPIOE
RO
1
GPIO Port E Present
When set, indicates that GPIO Port E is present.
3
GPIOD
RO
1
GPIO Port D Present
When set, indicates that GPIO Port D is present.
2
GPIOC
RO
1
GPIO Port C Present
When set, indicates that GPIO Port C is present.
1
GPIOB
RO
1
GPIO Port B Present
When set, indicates that GPIO Port B is present.
0
GPIOA
RO
1
GPIO Port A Present
When set, indicates that GPIO Port A is present.
254
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 21: Device Capabilities 5 (DC5), offset 0x020
This register is predefined by the part and can be used to verify features. If any bit is clear in this
register, the module is not present. The corresponding bit in the RCGC0, SCGC0, and DCGC0
registers cannot be set.
Device Capabilities 5 (DC5)
Base 0x400F.E000
Offset 0x020
Type RO, reset 0x0F30.00FF
31
30
29
28
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
1
RO
1
RO
0
RO
0
RO
1
15
14
13
12
11
10
9
8
7
6
PWM7
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
reserved
Type
Reset
27
26
25
24
RO
0
22
19
18
RO
1
RO
0
RO
0
RO
0
RO
0
5
4
3
2
1
0
PWM6
PWM5
PWM4
PWM3
PWM2
PWM1
PWM0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
reserved
PWMFAULT3 PWMFAULT2 PWMFAULT1 PWMFAULT0
reserved
Type
Reset
23
21
20
PWMEFLT PWMESYNC
17
16
reserved
Bit/Field
Name
Type
Reset
Description
31:28
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
27
PWMFAULT3
RO
1
PWM Fault 3 Pin Present
When set, indicates that the PWM Fault 3 pin is present.
26
PWMFAULT2
RO
1
PWM Fault 2 Pin Present
When set, indicates that the PWM Fault 2 pin is present.
25
PWMFAULT1
RO
1
PWM Fault 1 Pin Present
When set, indicates that the PWM Fault 1 pin is present.
24
PWMFAULT0
RO
1
PWM Fault 0 Pin Present
When set, indicates that the PWM Fault 0 pin is present.
23:22
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
21
PWMEFLT
RO
1
PWM Extended Fault Active
When set, indicates that the PWM Extended Fault feature is active.
20
PWMESYNC
RO
1
PWM Extended SYNC Active
When set, indicates that the PWM Extended SYNC feature is active.
19:8
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
PWM7
RO
1
PWM7 Pin Present
When set, indicates that the PWM pin 7 is present.
6
PWM6
RO
1
PWM6 Pin Present
When set, indicates that the PWM pin 6 is present.
July 03, 2014
255
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
5
PWM5
RO
1
Description
PWM5 Pin Present
When set, indicates that the PWM pin 5 is present.
4
PWM4
RO
1
PWM4 Pin Present
When set, indicates that the PWM pin 4 is present.
3
PWM3
RO
1
PWM3 Pin Present
When set, indicates that the PWM pin 3 is present.
2
PWM2
RO
1
PWM2 Pin Present
When set, indicates that the PWM pin 2 is present.
1
PWM1
RO
1
PWM1 Pin Present
When set, indicates that the PWM pin 1 is present.
0
PWM0
RO
1
PWM0 Pin Present
When set, indicates that the PWM pin 0 is present.
256
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 22: Device Capabilities 6 (DC6), offset 0x024
This register is predefined by the part and can be used to verify features. If any bit is clear in this
register, the module is not present. The corresponding bit in the RCGC0, SCGC0, and DCGC0
registers cannot be set.
Device Capabilities 6 (DC6)
Base 0x400F.E000
Offset 0x024
Type RO, reset 0x0000.0013
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
reserved
Type
Reset
reserved
Type
Reset
RO
0
USB0PHY
RO
1
reserved
RO
0
USB0
RO
1
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
USB0PHY
RO
1
USB Module 0 PHY Present
When set, indicates that the USB module 0 PHY is present.
3:2
reserved
RO
0
1:0
USB0
RO
0x3
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
USB Module 0 Present
Thie field indicates that USB module 0 is present and specifies its
capability.
Value Description
0x3
USB0 is OTG.
July 03, 2014
257
Texas Instruments-Production Data
System Control
Register 23: Device Capabilities 7 (DC7), offset 0x028
This register is predefined by the part and can be used to verify uDMA channel features. A 1 indicates
the channel is available on this device; a 0 that the channel is only available on other devices in the
family. Most channels have primary and secondary assignments. If the primary function is not
available on this microcontroller, the secondary function becomes the primary function. If the
secondary function is not available, the primary function is the only option.
Device Capabilities 7 (DC7)
Base 0x400F.E000
Offset 0x028
Type RO, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved DMACH30 DMACH29 DMACH28 DMACH27 DMACH26 DMACH25 DMACH24 DMACH23 DMACH22 DMACH21 DMACH20 DMACH19 DMACH18 DMACH17 DMACH16
Type
Reset
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
RO
1
RO
1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DMACH15 DMACH14 DMACH13 DMACH12 DMACH11 DMACH10 DMACH9 DMACH8 DMACH7 DMACH6 DMACH5 DMACH4 DMACH3 DMACH2 DMACH1 DMACH0
Type
Reset
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
Bit/Field
Name
Type
Reset
31
reserved
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
Description
Reserved
Reserved for uDMA channel 31.
30
DMACH30
RO
1
SW
When set, indicates uDMA channel 30 is available for software transfers.
29
DMACH29
RO
1
I2S0_TX / CAN1_TX
When set, indicates uDMA channel 29 is available and connected to
the transmit path of I2S module 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of CAN module 1 transmit.
28
DMACH28
RO
1
I2S0_RX / CAN1_RX
When set, indicates uDMA channel 28 is available and connected to
the receive path of I2S module 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of CAN module 1 receive.
27
DMACH27
RO
1
CAN1_TX / ADC1_SS3
When set, indicates uDMA channel 27 is available and connected to
the transmit path of CAN module 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of ADC module 1 Sample Sequencer
3.
26
DMACH26
RO
1
CAN1_RX / ADC1_SS2
When set, indicates uDMA channel 26 is available and connected to
the receive path of CAN module 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of ADC module 1 Sample Sequencer
2.
258
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
25
DMACH25
RO
1
Description
SSI1_TX / ADC1_SS1
When set, indicates uDMA channel 25 is available and connected to
the transmit path of SSI module 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of ADC module 1 Sample Sequencer
1.
24
DMACH24
RO
1
SSI1_RX / ADC1_SS0
When set, indicates uDMA channel 24 is available and connected to
the receive path of SSI module 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of ADC module 1 Sample Sequencer
0.
23
DMACH23
RO
1
UART1_TX / CAN2_TX
When set, indicates uDMA channel 23 is available and connected to
the transmit path of UART module 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of CAN module 2 transmit.
22
DMACH22
RO
1
UART1_RX / CAN2_RX
When set, indicates uDMA channel 22 is available and connected to
the receive path of UART module 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of CAN module 2 receive.
21
DMACH21
RO
1
Timer1B / EPI0_WFIFO
When set, indicates uDMA channel 21 is available and connected to
Timer 1B. If the corresponding bit in the DMACHASGN register is set,
the channel is connected instead to the secondary channel assignment
of EPI module 0 write FIFO (WRIFO).
20
DMACH20
RO
1
Timer1A / EPI0_NBRFIFO
When set, indicates uDMA channel 20 is available and connected to
Timer 1A. If the corresponding bit in the DMACHASGN register is set,
the channel is connected instead to the secondary channel assignment
of EPI module 0 non-blocking read FIFO (NBRFIFO).
19
DMACH19
RO
1
Timer0B / Timer1B
When set, indicates uDMA channel 19 is available and connected to
Timer 0B. If the corresponding bit in the DMACHASGN register is set,
the channel is connected instead to the secondary channel assignment
of Timer 1B.
18
DMACH18
RO
1
Timer0A / Timer1A
When set, indicates uDMA channel 18 is available and connected to
Timer 0A. If the corresponding bit in the DMACHASGN register is set,
the channel is connected instead to the secondary channel assignment
of Timer 1A.
17
DMACH17
RO
1
ADC0_SS3
When set, indicates uDMA channel 17 is available and connected to
ADC module 0 Sample Sequencer 3.
16
DMACH16
RO
1
ADC0_SS2
When set, indicates uDMA channel 16 is available and connected to
ADC module 0 Sample Sequencer 2.
July 03, 2014
259
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
15
DMACH15
RO
1
Description
ADC0_SS1 / Timer2B
When set, indicates uDMA channel 15 is available and connected to
ADC module 0 Sample Sequencer 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of Timer 2B.
14
DMACH14
RO
1
ADC0_SS0 / Timer2A
When set, indicates uDMA channel 14 is available and connected to
ADC module 0 Sample Sequencer 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of Timer 2A.
13
DMACH13
RO
1
CAN0_TX / UART2_TX
When set, indicates uDMA channel 13 is available and connected to
the transmit path of CAN module 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of UART module 2 transmit.
12
DMACH12
RO
1
CAN0_RX / UART2_RX
When set, indicates uDMA channel 12 is available and connected to
the receive path of CAN module 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of UART module 2 receive.
11
DMACH11
RO
1
SSI0_TX / SSI1_TX
When set, indicates uDMA channel 11 is available and connected to
the transmit path of SSI module 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of SSI module 1 transmit.
10
DMACH10
RO
1
SSI0_RX / SSI1_RX
When set, indicates uDMA channel 10 is available and connected to
the receive path of SSI module 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of SSI module 1 receive.
9
DMACH9
RO
1
UART0_TX / UART1_TX
When set, indicates uDMA channel 9 is available and connected to the
transmit path of UART module 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of UART module 1 transmit.
8
DMACH8
RO
1
UART0_RX / UART1_RX
When set, indicates uDMA channel 8 is available and connected to the
receive path of UART module 0. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of UART module 1 receive.
7
DMACH7
RO
1
ETH_TX / Timer2B
When set, indicates uDMA channel 7 is available and connected to the
transmit path of the Ethernet module. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of Timer 2B.
260
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
6
DMACH6
RO
1
Description
ETH_RX / Timer2A
When set, indicates uDMA channel 6 is available and connected to the
receive path of the Ethernet module. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of Timer 2A.
5
DMACH5
RO
1
USB_EP3_TX / Timer2B
When set, indicates uDMA channel 5 is available and connected to the
transmit path of USB endpoint 3. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of Timer 2B.
4
DMACH4
RO
1
USB_EP3_RX / Timer2A
When set, indicates uDMA channel 4 is available and connected to the
receive path of USB endpoint 3. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of Timer 2A.
3
DMACH3
RO
1
USB_EP2_TX / Timer3B
When set, indicates uDMA channel 3 is available and connected to the
transmit path of USB endpoint 2. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of Timer 3B.
2
DMACH2
RO
1
USB_EP2_RX / Timer3A
When set, indicates uDMA channel 2 is available and connected to the
receive path of USB endpoint 2. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of Timer 3A.
1
DMACH1
RO
1
USB_EP1_TX / UART2_TX
When set, indicates uDMA channel 1 is available and connected to the
transmit path of USB endpoint 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of UART module 2 transmit.
0
DMACH0
RO
1
USB_EP1_RX / UART2_RX
When set, indicates uDMA channel 0 is available and connected to the
receive path of USB endpoint 1. If the corresponding bit in the
DMACHASGN register is set, the channel is connected instead to the
secondary channel assignment of UART module 2 receive.
July 03, 2014
261
Texas Instruments-Production Data
System Control
Register 24: Device Capabilities 8 ADC Channels (DC8), offset 0x02C
This register is predefined by the part and can be used to verify features.
Device Capabilities 8 ADC Channels (DC8)
Base 0x400F.E000
Offset 0x02C
Type RO, reset 0xFFFF.FFFF
Type
Reset
Type
Reset
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
ADC1AIN15
ADC1AIN14
ADC1AIN13
ADC1AIN12
ADC1AIN11
ADC1AIN10
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
RO
1
RO
1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ADC0AIN15
ADC0AIN14
ADC0AIN13
ADC0AIN12
ADC0AIN11
ADC0AIN10
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
ADC1AIN9 ADC1AIN8 ADC1AIN7 ADC1AIN6 ADC1AIN5 ADC1AIN4 ADC1AIN3 ADC1AIN2 ADC1AIN1 ADC1AIN0
ADC0AIN9 ADC0AIN8 ADC0AIN7 ADC0AIN6 ADC0AIN5 ADC0AIN4 ADC0AIN3 ADC0AIN2 ADC0AIN1 ADC0AIN0
RO
1
Bit/Field
Name
Type
Reset
31
ADC1AIN15
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
Description
ADC Module 1 AIN15 Pin Present
When set, indicates that ADC module 1 input pin 15 is present.
30
ADC1AIN14
RO
1
ADC Module 1 AIN14 Pin Present
When set, indicates that ADC module 1 input pin 14 is present.
29
ADC1AIN13
RO
1
ADC Module 1 AIN13 Pin Present
When set, indicates that ADC module 1 input pin 13 is present.
28
ADC1AIN12
RO
1
ADC Module 1 AIN12 Pin Present
When set, indicates that ADC module 1 input pin 12 is present.
27
ADC1AIN11
RO
1
ADC Module 1 AIN11 Pin Present
When set, indicates that ADC module 1 input pin 11 is present.
26
ADC1AIN10
RO
1
ADC Module 1 AIN10 Pin Present
When set, indicates that ADC module 1 input pin 10 is present.
25
ADC1AIN9
RO
1
ADC Module 1 AIN9 Pin Present
When set, indicates that ADC module 1 input pin 9 is present.
24
ADC1AIN8
RO
1
ADC Module 1 AIN8 Pin Present
When set, indicates that ADC module 1 input pin 8 is present.
23
ADC1AIN7
RO
1
ADC Module 1 AIN7 Pin Present
When set, indicates that ADC module 1 input pin 7 is present.
22
ADC1AIN6
RO
1
ADC Module 1 AIN6 Pin Present
When set, indicates that ADC module 1 input pin 6 is present.
21
ADC1AIN5
RO
1
ADC Module 1 AIN5 Pin Present
When set, indicates that ADC module 1 input pin 5 is present.
20
ADC1AIN4
RO
1
ADC Module 1 AIN4 Pin Present
When set, indicates that ADC module 1 input pin 4 is present.
262
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
19
ADC1AIN3
RO
1
Description
ADC Module 1 AIN3 Pin Present
When set, indicates that ADC module 1 input pin 3 is present.
18
ADC1AIN2
RO
1
ADC Module 1 AIN2 Pin Present
When set, indicates that ADC module 1 input pin 2 is present.
17
ADC1AIN1
RO
1
ADC Module 1 AIN1 Pin Present
When set, indicates that ADC module 1 input pin 1 is present.
16
ADC1AIN0
RO
1
ADC Module 1 AIN0 Pin Present
When set, indicates that ADC module 1 input pin 0 is present.
15
ADC0AIN15
RO
1
ADC Module 0 AIN15 Pin Present
When set, indicates that ADC module 0 input pin 15 is present.
14
ADC0AIN14
RO
1
ADC Module 0 AIN14 Pin Present
When set, indicates that ADC module 0 input pin 14 is present.
13
ADC0AIN13
RO
1
ADC Module 0 AIN13 Pin Present
When set, indicates that ADC module 0 input pin 13 is present.
12
ADC0AIN12
RO
1
ADC Module 0 AIN12 Pin Present
When set, indicates that ADC module 0 input pin 12 is present.
11
ADC0AIN11
RO
1
ADC Module 0 AIN11 Pin Present
When set, indicates that ADC module 0 input pin 11 is present.
10
ADC0AIN10
RO
1
ADC Module 0 AIN10 Pin Present
When set, indicates that ADC module 0 input pin 10 is present.
9
ADC0AIN9
RO
1
ADC Module 0 AIN9 Pin Present
When set, indicates that ADC module 0 input pin 9 is present.
8
ADC0AIN8
RO
1
ADC Module 0 AIN8 Pin Present
When set, indicates that ADC module 0 input pin 8 is present.
7
ADC0AIN7
RO
1
ADC Module 0 AIN7 Pin Present
When set, indicates that ADC module 0 input pin 7 is present.
6
ADC0AIN6
RO
1
ADC Module 0 AIN6 Pin Present
When set, indicates that ADC module 0 input pin 6 is present.
5
ADC0AIN5
RO
1
ADC Module 0 AIN5 Pin Present
When set, indicates that ADC module 0 input pin 5 is present.
4
ADC0AIN4
RO
1
ADC Module 0 AIN4 Pin Present
When set, indicates that ADC module 0 input pin 4 is present.
3
ADC0AIN3
RO
1
ADC Module 0 AIN3 Pin Present
When set, indicates that ADC module 0 input pin 3 is present.
2
ADC0AIN2
RO
1
ADC Module 0 AIN2 Pin Present
When set, indicates that ADC module 0 input pin 2 is present.
July 03, 2014
263
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
1
ADC0AIN1
RO
1
Description
ADC Module 0 AIN1 Pin Present
When set, indicates that ADC module 0 input pin 1 is present.
0
ADC0AIN0
RO
1
ADC Module 0 AIN0 Pin Present
When set, indicates that ADC module 0 input pin 0 is present.
264
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 25: Device Capabilities 9 ADC Digital Comparators (DC9), offset
0x190
This register is predefined by the part and can be used to verify features.
Device Capabilities 9 ADC Digital Comparators (DC9)
Base 0x400F.E000
Offset 0x190
Type RO, reset 0x00FF.00FF
31
30
29
28
27
26
25
24
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
ADC1DC7 ADC1DC6 ADC1DC5 ADC1DC4 ADC1DC3 ADC1DC2 ADC1DC1 ADC1DC0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
7
6
5
4
3
2
1
0
ADC0DC7 ADC0DC6 ADC0DC5 ADC0DC4 ADC0DC3 ADC0DC2 ADC0DC1 ADC0DC0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
Bit/Field
Name
Type
Reset
Description
31:24
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
ADC1DC7
RO
1
ADC1 DC7 Present
When set, indicates that ADC module 1 Digital Comparator 7 is present.
22
ADC1DC6
RO
1
ADC1 DC6 Present
When set, indicates that ADC module 1 Digital Comparator 6 is present.
21
ADC1DC5
RO
1
ADC1 DC5 Present
When set, indicates that ADC module 1 Digital Comparator 5 is present.
20
ADC1DC4
RO
1
ADC1 DC4 Present
When set, indicates that ADC module 1 Digital Comparator 4 is present.
19
ADC1DC3
RO
1
ADC1 DC3 Present
When set, indicates that ADC module 1 Digital Comparator 3 is present.
18
ADC1DC2
RO
1
ADC1 DC2 Present
When set, indicates that ADC module 1 Digital Comparator 2 is present.
17
ADC1DC1
RO
1
ADC1 DC1 Present
When set, indicates that ADC module 1 Digital Comparator 1 is present.
16
ADC1DC0
RO
1
ADC1 DC0 Present
When set, indicates that ADC module 1 Digital Comparator 0 is present.
15:8
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
ADC0DC7
RO
1
ADC0 DC7 Present
When set, indicates that ADC module 0 Digital Comparator 7 is present.
July 03, 2014
265
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
6
ADC0DC6
RO
1
Description
ADC0 DC6 Present
When set, indicates that ADC module 0 Digital Comparator 6 is present.
5
ADC0DC5
RO
1
ADC0 DC5 Present
When set, indicates that ADC module 0 Digital Comparator 5 is present.
4
ADC0DC4
RO
1
ADC0 DC4 Present
When set, indicates that ADC module 0 Digital Comparator 4 is present.
3
ADC0DC3
RO
1
ADC0 DC3 Present
When set, indicates that ADC module 0 Digital Comparator 3 is present.
2
ADC0DC2
RO
1
ADC0 DC2 Present
When set, indicates that ADC module 0 Digital Comparator 2 is present.
1
ADC0DC1
RO
1
ADC0 DC1 Present
When set, indicates that ADC module 0 Digital Comparator 1 is present.
0
ADC0DC0
RO
1
ADC0 DC0 Present
When set, indicates that ADC module 0 Digital Comparator 0 is present.
266
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 26: Non-Volatile Memory Information (NVMSTAT), offset 0x1A0
This register is predefined by the part and can be used to verify features.
Non-Volatile Memory Information (NVMSTAT)
Base 0x400F.E000
Offset 0x1A0
Type RO, reset 0x0000.0001
31
30
29
28
27
26
25
24
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
FWB
RO
1
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
FWB
RO
1
32 Word Flash Write Buffer Active
When set, indicates that the 32 word Flash memory write buffer feature
is active.
July 03, 2014
267
Texas Instruments-Production Data
System Control
Register 27: Run Mode Clock Gating Control Register 0 (RCGC0), offset 0x100
This register controls the clock gating logic in normal Run mode. Each bit controls a clock enable
for a given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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
reserved
Type
Reset
28
WDT1
26
24
23
22
21
19
16
CAN1
CAN0
ADC1
ADC0
RO
0
RO
0
R/W
0
R/W
0
RO
0
RO
0
RO
0
R/W
0
RO
0
RO
0
R/W
0
R/W
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
reserved
RO
0
RO
0
RO
0
RO
1
MAXADC0SPD
R/W
0
R/W
0
R/W
0
R/W
0
reserved
RO
0
RO
0
reserved
17
R/W
0
MAXADC1SPD
PWM
18
RO
0
RO
0
reserved
20
RO
0
RO
0
reserved
25
RO
0
reserved
Type
Reset
27
WDT0
R/W
0
reserved
RO
0
RO
0
RO
0
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
WDT1
R/W
0
WDT1 Clock Gating Control
This bit controls the clock gating for the Watchdog Timer module 1. If
set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
27:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
CAN1
R/W
0
CAN1 Clock Gating Control
This bit controls the clock gating for CAN module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
24
CAN0
R/W
0
CAN0 Clock Gating Control
This bit controls the clock gating for CAN module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
268
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
23:21
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
20
PWM
R/W
0
PWM Clock Gating Control
This bit controls the clock gating for the PWM module. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
19:18
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
17
ADC1
R/W
0
ADC1 Clock Gating Control
This bit controls the clock gating for SAR ADC module 1. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates a bus fault.
16
ADC0
R/W
0
ADC0 Clock Gating Control
This bit controls the clock gating for ADC module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
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.
11:10
MAXADC1SPD
R/W
0
ADC1 Sample Speed
This field sets the rate at which ADC module 1 samples data. You cannot
set the rate higher than the maximum rate. You can set the sample rate
by setting the MAXADC1SPD bit as follows (all other encodings are
reserved):
Value Description
9:8
MAXADC0SPD
R/W
0
0x3
1M samples/second
0x2
500K samples/second
0x1
250K samples/second
0x0
125K samples/second
ADC0 Sample Speed
This field sets the rate at which ADC0 samples data. You cannot set
the rate higher than the maximum rate. You can set the sample rate by
setting the MAXADC0SPD bit as follows (all other encodings are reserved):
Value Description
0x3
1M samples/second
0x2
500K samples/second
0x1
250K samples/second
0x0
125K samples/second
July 03, 2014
269
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
Description
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
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.
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
WDT0
R/W
0
WDT0 Clock Gating Control
This bit controls the clock gating for the Watchdog Timer module 0. If
set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module 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.
270
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 28: Sleep Mode Clock Gating Control Register 0 (SCGC0), offset
0x110
This register controls the clock gating logic in Sleep mode. Each bit controls a clock enable for a
given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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.
Sleep Mode Clock Gating Control Register 0 (SCGC0)
Base 0x400F.E000
Offset 0x110
Type R/W, reset 0x00000040
31
30
29
reserved
Type
Reset
28
WDT1
RO
0
RO
0
RO
0
R/W
0
15
14
13
12
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
27
26
reserved
RO
0
RO
0
11
10
25
24
CAN1
CAN0
R/W
0
R/W
0
9
8
MAXADC1SPD
MAXADC0SPD
R/W
0
R/W
0
R/W
0
R/W
0
23
22
21
reserved
RO
0
20
RO
0
RO
0
R/W
0
5
4
7
6
reserved
reserved
RO
0
RO
1
19
PWM
reserved
RO
0
RO
0
18
reserved
RO
0
RO
0
3
2
WDT0
R/W
0
17
16
ADC1
ADC0
R/W
0
R/W
0
1
0
reserved
RO
0
RO
0
RO
0
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
WDT1
R/W
0
WDT1 Clock Gating Control
This bit controls the clock gating for Watchdog Timer module 1. If set,
the module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates a bus fault.
27:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
CAN1
R/W
0
CAN1 Clock Gating Control
This bit controls the clock gating for CAN module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
24
CAN0
R/W
0
CAN0 Clock Gating Control
This bit controls the clock gating for CAN module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
July 03, 2014
271
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
Description
23:21
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
20
PWM
R/W
0
PWM Clock Gating Control
This bit controls the clock gating for the PWM module. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
19:18
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
17
ADC1
R/W
0
ADC1 Clock Gating Control
This bit controls the clock gating for ADC module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
16
ADC0
R/W
0
ADC0 Clock Gating Control
This bit controls the clock gating for ADC module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
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.
11:10
MAXADC1SPD
R/W
0
ADC1 Sample Speed
This field sets the rate at which ADC module 1 samples data. You cannot
set the rate higher than the maximum rate. You can set the sample rate
by setting the MAXADC1SPD bit as follows (all other encodings are
reserved):
Value Description
9:8
MAXADC0SPD
R/W
0
0x3
1M samples/second
0x2
500K samples/second
0x1
250K samples/second
0x0
125K samples/second
ADC0 Sample Speed
This field sets the rate at which ADC module 0 samples data. You cannot
set the rate higher than the maximum rate. You can set the sample rate
by setting the MAXADC0SPD bit as follows (all other encodings are
reserved):
Value Description
0x3
1M samples/second
0x2
500K samples/second
0x1
250K samples/second
0x0
125K samples/second
272
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
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
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.
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
WDT0
R/W
0
WDT0 Clock Gating Control
This bit controls the clock gating for the Watchdog Timer module 0. If
set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module 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.
July 03, 2014
273
Texas Instruments-Production Data
System Control
Register 29: Deep Sleep Mode Clock Gating Control Register 0 (DCGC0),
offset 0x120
This register controls the clock gating logic in Deep-Sleep mode. Each bit controls a clock enable
for a given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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.
Deep Sleep Mode Clock Gating Control Register 0 (DCGC0)
Base 0x400F.E000
Offset 0x120
Type R/W, reset 0x00000040
31
30
29
reserved
Type
Reset
28
WDT1
RO
0
RO
0
RO
0
R/W
0
15
14
13
12
27
26
reserved
25
24
CAN1
CAN0
23
RO
0
RO
0
R/W
0
R/W
0
RO
0
11
10
9
8
7
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
22
RO
0
RO
0
RO
0
RO
0
20
RO
0
R/W
0
6
5
4
RO
1
19
PWM
RO
0
reserved
RO
0
21
reserved
reserved
RO
0
RO
0
18
reserved
RO
0
RO
0
3
2
WDT0
R/W
0
17
16
ADC1
ADC0
R/W
0
R/W
0
1
0
reserved
RO
0
RO
0
RO
0
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
WDT1
R/W
0
WDT1 Clock Gating Control
This bit controls the clock gating for the Watchdog Timer module 1. If
set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
27:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
CAN1
R/W
0
CAN1 Clock Gating Control
This bit controls the clock gating for CAN module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
24
CAN0
R/W
0
CAN0 Clock Gating Control
This bit controls the clock gating for CAN module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
274
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
23:21
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
20
PWM
R/W
0
PWM Clock Gating Control
This bit controls the clock gating for the PWM module. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
19:18
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
17
ADC1
R/W
0
ADC1 Clock Gating Control
This bit controls the clock gating for ADC module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
16
ADC0
R/W
0
ADC0 Clock Gating Control
This bit controls the clock gating for ADC module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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
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.
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
WDT0
R/W
0
WDT0 Clock Gating Control
This bit controls the clock gating for the Watchdog Timer module 0. If
set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module 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.
July 03, 2014
275
Texas Instruments-Production Data
System Control
Register 30: Run Mode Clock Gating Control Register 1 (RCGC1), offset 0x104
This register controls the clock gating logic in normal Run mode. Each bit controls a clock enable
for a given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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
Type
Reset
Type
Reset
31
30
29
28
27
26
25
24
reserved
EPI0
reserved
I2S0
reserved
COMP2
COMP1
COMP0
RO
0
R/W
0
RO
0
R/W
0
RO
0
R/W
0
R/W
0
15
14
13
12
11
10
reserved
I2C1
reserved
I2C0
RO
0
R/W
0
RO
0
R/W
0
reserved
RO
0
RO
0
23
22
21
20
19
18
17
16
R/W
0
RO
0
RO
0
RO
0
RO
0
TIMER3
TIMER2
TIMER1
TIMER0
R/W
0
R/W
0
R/W
0
R/W
0
9
8
7
6
5
4
3
2
1
0
QEI1
QEI0
R/W
0
R/W
0
SSI1
SSI0
reserved
UART2
UART1
UART0
R/W
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
reserved
reserved
RO
0
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
EPI0
R/W
0
EPI0 Clock Gating
This bit controls the clock gating for EPI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates 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
I2S0
R/W
0
I2S0 Clock Gating
This bit controls the clock gating for I2S module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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.
276
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
26
COMP2
R/W
0
Description
Analog Comparator 2 Clock Gating
This bit controls the clock gating for analog comparator 2. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates a bus fault.
25
COMP1
R/W
0
Analog Comparator 1 Clock Gating
This bit controls the clock gating for analog comparator 1. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates a bus fault.
24
COMP0
R/W
0
Analog Comparator 0 Clock Gating
This bit controls the clock gating for analog comparator 0. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates 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
Timer 3 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 3.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
18
TIMER2
R/W
0
Timer 2 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 2.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
17
TIMER1
R/W
0
Timer 1 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 1.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
16
TIMER0
R/W
0
Timer 0 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 0.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates 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
I2C1 Clock Gating Control
This bit controls the clock gating for I2C module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
July 03, 2014
277
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
Description
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
I2C0 Clock Gating Control
This bit controls the clock gating for I2C module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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
QEI1
R/W
0
QEI1 Clock Gating Control
This bit controls the clock gating for QEI module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
8
QEI0
R/W
0
QEI0 Clock Gating Control
This bit controls the clock gating for QEI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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
SSI1
R/W
0
SSI1 Clock Gating Control
This bit controls the clock gating for SSI module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
4
SSI0
R/W
0
SSI0 Clock Gating Control
This bit controls the clock gating for SSI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates 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
UART2 Clock Gating Control
This bit controls the clock gating for UART module 2. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
1
UART1
R/W
0
UART1 Clock Gating Control
This bit controls the clock gating for UART module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
278
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
0
UART0
R/W
0
Description
UART0 Clock Gating Control
This bit controls the clock gating for UART module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
July 03, 2014
279
Texas Instruments-Production Data
System Control
Register 31: Sleep Mode Clock Gating Control Register 1 (SCGC1), offset
0x114
This register controls the clock gating logic in Sleep mode. Each bit controls a clock enable for a
given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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
Type
Reset
Type
Reset
31
30
29
28
27
26
25
24
reserved
EPI0
reserved
I2S0
reserved
COMP2
COMP1
COMP0
RO
0
R/W
0
RO
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
RO
0
RO
0
11
10
7
6
15
14
13
12
reserved
I2C1
reserved
I2C0
RO
0
R/W
0
RO
0
R/W
0
reserved
RO
0
RO
0
9
8
QEI1
QEI0
R/W
0
R/W
0
23
22
21
20
reserved
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
5
4
3
2
1
0
SSI1
SSI0
reserved
UART2
UART1
UART0
R/W
0
R/W
0
RO
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
EPI0
R/W
0
EPI0 Clock Gating
This bit controls the clock gating for EPI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates 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
I2S0
R/W
0
I2S0 Clock Gating
This bit controls the clock gating for I2S module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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.
280
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
26
COMP2
R/W
0
Description
Analog Comparator 2 Clock Gating
This bit controls the clock gating for analog comparator 2. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates a bus fault.
25
COMP1
R/W
0
Analog Comparator 1 Clock Gating
This bit controls the clock gating for analog comparator 1. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates a bus fault.
24
COMP0
R/W
0
Analog Comparator 0 Clock Gating
This bit controls the clock gating for analog comparator 0. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates 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
Timer 3 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 3.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
18
TIMER2
R/W
0
Timer 2 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 2.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
17
TIMER1
R/W
0
Timer 1 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 1.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
16
TIMER0
R/W
0
Timer 0 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 0.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates 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
I2C1 Clock Gating Control
This bit controls the clock gating for I2C module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
July 03, 2014
281
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
Description
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
I2C0 Clock Gating Control
This bit controls the clock gating for I2C module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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
QEI1
R/W
0
QEI1 Clock Gating Control
This bit controls the clock gating for QEI module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
8
QEI0
R/W
0
QEI0 Clock Gating Control
This bit controls the clock gating for QEI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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
SSI1
R/W
0
SSI1 Clock Gating Control
This bit controls the clock gating for SSI module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
4
SSI0
R/W
0
SSI0 Clock Gating Control
This bit controls the clock gating for SSI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates 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
UART2 Clock Gating Control
This bit controls the clock gating for UART module 2. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
1
UART1
R/W
0
UART1 Clock Gating Control
This bit controls the clock gating for UART module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
282
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
0
UART0
R/W
0
Description
UART0 Clock Gating Control
This bit controls the clock gating for UART module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
July 03, 2014
283
Texas Instruments-Production Data
System Control
Register 32: Deep-Sleep Mode Clock Gating Control Register 1 (DCGC1),
offset 0x124
This register controls the clock gating logic in Deep-Sleep mode. Each bit controls a clock enable
for a given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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
Type
Reset
Type
Reset
31
30
29
28
27
26
25
24
reserved
EPI0
reserved
I2S0
reserved
COMP2
COMP1
COMP0
RO
0
R/W
0
RO
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
RO
0
RO
0
11
10
7
6
15
14
13
12
reserved
I2C1
reserved
I2C0
RO
0
R/W
0
RO
0
R/W
0
reserved
RO
0
RO
0
9
8
QEI1
QEI0
R/W
0
R/W
0
23
22
21
20
reserved
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
5
4
3
2
1
0
SSI1
SSI0
reserved
UART2
UART1
UART0
R/W
0
R/W
0
RO
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
EPI0
R/W
0
EPI0 Clock Gating
This bit controls the clock gating for EPI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates 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
I2S0
R/W
0
I2S0 Clock Gating
This bit controls the clock gating for I2S module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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.
284
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
26
COMP2
R/W
0
Description
Analog Comparator 2 Clock Gating
This bit controls the clock gating for analog comparator 2. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates a bus fault.
25
COMP1
R/W
0
Analog Comparator 1 Clock Gating
This bit controls the clock gating for analog comparator 1. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates a bus fault.
24
COMP0
R/W
0
Analog Comparator 0 Clock Gating
This bit controls the clock gating for analog comparator 0. If set, the
module receives a clock and functions. Otherwise, the module is
unclocked and disabled. If the module is unclocked, a read or write to
the module generates 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
Timer 3 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 3.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
18
TIMER2
R/W
0
Timer 2 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 2.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
17
TIMER1
R/W
0
Timer 1 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 1.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates a bus fault.
16
TIMER0
R/W
0
Timer 0 Clock Gating Control
This bit controls the clock gating for General-Purpose Timer module 0.
If set, the module receives a clock and functions. Otherwise, the module
is unclocked and disabled. If the module is unclocked, a read or write
to the module generates 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
I2C1 Clock Gating Control
This bit controls the clock gating for I2C module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
July 03, 2014
285
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
Description
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
I2C0 Clock Gating Control
This bit controls the clock gating for I2C module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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
QEI1
R/W
0
QEI1 Clock Gating Control
This bit controls the clock gating for QEI module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
8
QEI0
R/W
0
QEI0 Clock Gating Control
This bit controls the clock gating for QEI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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
SSI1
R/W
0
SSI1 Clock Gating Control
This bit controls the clock gating for SSI module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
4
SSI0
R/W
0
SSI0 Clock Gating Control
This bit controls the clock gating for SSI module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates 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
UART2 Clock Gating Control
This bit controls the clock gating for UART module 2. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
1
UART1
R/W
0
UART1 Clock Gating Control
This bit controls the clock gating for UART module 1. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
286
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
0
UART0
R/W
0
Description
UART0 Clock Gating Control
This bit controls the clock gating for UART module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
July 03, 2014
287
Texas Instruments-Production Data
System Control
Register 33: Run Mode Clock Gating Control Register 2 (RCGC2), offset 0x108
This register controls the clock gating logic in normal Run mode. Each bit controls a clock enable
for a given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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
27
26
25
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
24
23
22
21
20
19
18
17
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
8
7
6
5
4
3
2
1
0
GPIOJ
GPIOH
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
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
RO
0
UDMA
R/W
0
reserved
RO
0
RO
0
16
USB0
Bit/Field
Name
Type
Reset
Description
31:17
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
16
USB0
R/W
0
USB0 Clock Gating Control
This bit controls the clock gating for USB module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
15:14
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
UDMA
R/W
0
Micro-DMA Clock Gating Control
This bit controls the clock gating for micro-DMA. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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.
288
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
8
GPIOJ
R/W
0
Description
Port J Clock Gating Control
This bit controls the clock gating for Port J. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
7
GPIOH
R/W
0
Port H Clock Gating Control
This bit controls the clock gating for Port H. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
6
GPIOG
R/W
0
Port G Clock Gating Control
This bit controls the clock gating for Port G. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
5
GPIOF
R/W
0
Port F Clock Gating Control
This bit controls the clock gating for Port F. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
4
GPIOE
R/W
0
Port E Clock Gating Control
Port E Clock Gating Control. This bit controls the clock gating for Port
E. If set, the module receives a clock and functions. Otherwise, the
module is unclocked and disabled. If the module is unclocked, a read
or write to the module generates a bus fault.
3
GPIOD
R/W
0
Port D Clock Gating Control
Port D Clock Gating Control. This bit controls the clock gating for Port
D. If set, the module receives a clock and functions. Otherwise, the
module is unclocked and disabled. If the module is unclocked, a read
or write to the module generates a bus fault.
2
GPIOC
R/W
0
Port C Clock Gating Control
This bit controls the clock gating for Port C. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
1
GPIOB
R/W
0
Port B Clock Gating Control
This bit controls the clock gating for Port B. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
0
GPIOA
R/W
0
Port A Clock Gating Control
This bit controls the clock gating for Port A. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
July 03, 2014
289
Texas Instruments-Production Data
System Control
Register 34: Sleep Mode Clock Gating Control Register 2 (SCGC2), offset
0x118
This register controls the clock gating logic in Sleep mode. Each bit controls a clock enable for a
given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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
27
26
25
24
23
22
21
20
19
18
17
reserved
Type
Reset
RO
0
RO
0
15
14
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
13
12
11
10
9
UDMA
R/W
0
reserved
RO
0
RO
0
RO
0
RO
0
RO
0
16
USB0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
8
7
6
5
4
3
2
1
0
GPIOJ
GPIOH
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
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:17
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
16
USB0
R/W
0
USB0 Clock Gating Control
This bit controls the clock gating for USB module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
15:14
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
UDMA
R/W
0
Micro-DMA Clock Gating Control
This bit controls the clock gating for micro-DMA. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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.
290
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
8
GPIOJ
R/W
0
Description
Port J Clock Gating Control
This bit controls the clock gating for Port J. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
7
GPIOH
R/W
0
Port H Clock Gating Control
This bit controls the clock gating for Port H. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
6
GPIOG
R/W
0
Port G Clock Gating Control
This bit controls the clock gating for Port G. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
5
GPIOF
R/W
0
Port F Clock Gating Control
This bit controls the clock gating for Port F. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
4
GPIOE
R/W
0
Port E Clock Gating Control
Port E Clock Gating Control. This bit controls the clock gating for Port
E. If set, the module receives a clock and functions. Otherwise, the
module is unclocked and disabled. If the module is unclocked, a read
or write to the module generates a bus fault.
3
GPIOD
R/W
0
Port D Clock Gating Control
Port D Clock Gating Control. This bit controls the clock gating for Port
D. If set, the module receives a clock and functions. Otherwise, the
module is unclocked and disabled. If the module is unclocked, a read
or write to the module generates a bus fault.
2
GPIOC
R/W
0
Port C Clock Gating Control
This bit controls the clock gating for Port C. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
1
GPIOB
R/W
0
Port B Clock Gating Control
This bit controls the clock gating for Port B. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
0
GPIOA
R/W
0
Port A Clock Gating Control
This bit controls the clock gating for Port A. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
July 03, 2014
291
Texas Instruments-Production Data
System Control
Register 35: Deep Sleep Mode Clock Gating Control Register 2 (DCGC2),
offset 0x128
This register controls the clock gating logic in Deep-Sleep mode. Each bit controls a clock enable
for a given interface, function, or module. If set, the module receives a clock and functions. Otherwise,
the module is unclocked and disabled (saving power). If the module is unclocked, reads or writes
to the module generate a bus fault. The reset state of these bits is 0 (unclocked) unless otherwise
noted, so that all functional modules 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 modules to control. This configuration is implemented 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
27
26
25
24
23
22
21
20
19
18
17
reserved
Type
Reset
RO
0
RO
0
15
14
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
13
12
11
10
9
UDMA
R/W
0
reserved
RO
0
RO
0
RO
0
RO
0
RO
0
16
USB0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
8
7
6
5
4
3
2
1
0
GPIOJ
GPIOH
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
R/W
0
R/W
0
Bit/Field
Name
Type
Reset
Description
31:17
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
16
USB0
R/W
0
USB0 Clock Gating Control
This bit controls the clock gating for USB module 0. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
15:14
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
UDMA
R/W
0
Micro-DMA Clock Gating Control
This bit controls the clock gating for micro-DMA. If set, the module
receives a clock and functions. Otherwise, the module is unclocked and
disabled. If the module is unclocked, a read or write to the module
generates a bus fault.
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.
292
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
8
GPIOJ
R/W
0
Description
Port J Clock Gating Control
This bit controls the clock gating for Port J. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
7
GPIOH
R/W
0
Port H Clock Gating Control
This bit controls the clock gating for Port H. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
6
GPIOG
R/W
0
Port G Clock Gating Control
This bit controls the clock gating for Port G. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
5
GPIOF
R/W
0
Port F Clock Gating Control
This bit controls the clock gating for Port F. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
4
GPIOE
R/W
0
Port E Clock Gating Control
Port E Clock Gating Control. This bit controls the clock gating for Port
E. If set, the module receives a clock and functions. Otherwise, the
module is unclocked and disabled. If the module is unclocked, a read
or write to the module generates a bus fault.
3
GPIOD
R/W
0
Port D Clock Gating Control
Port D Clock Gating Control. This bit controls the clock gating for Port
D. If set, the module receives a clock and functions. Otherwise, the
module is unclocked and disabled. If the module is unclocked, a read
or write to the module generates a bus fault.
2
GPIOC
R/W
0
Port C Clock Gating Control
This bit controls the clock gating for Port C. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
1
GPIOB
R/W
0
Port B Clock Gating Control
This bit controls the clock gating for Port B. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
0
GPIOA
R/W
0
Port A Clock Gating Control
This bit controls the clock gating for Port A. If set, the module receives
a clock and functions. Otherwise, the module is unclocked and disabled.
If the module is unclocked, a read or write to the module generates a
bus fault.
July 03, 2014
293
Texas Instruments-Production Data
System Control
Register 36: Software Reset Control 0 (SRCR0), offset 0x040
This register allows individual modules to be reset. 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
reserved
Type
Reset
28
WDT1
27
26
reserved
25
24
23
22
21
reserved
20
PWM
18
reserved
17
16
CAN1
CAN0
ADC1
ADC0
RO
0
RO
0
RO
0
R/W
0
RO
0
RO
0
R/W
0
R/W
0
RO
0
RO
0
RO
0
R/W
0
RO
0
RO
0
R/W
0
R/W
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
reserved
Type
Reset
19
WDT0
R/W
0
reserved
RO
0
RO
0
RO
0
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
WDT1
R/W
0
WDT1 Reset Control
When this bit is set, Watchdog Timer module 1 is reset. All internal data
is lost and the registers are returned to their reset states. This bit must
be manually cleared after being set.
27:26
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
25
CAN1
R/W
0
CAN1 Reset Control
When this bit is set, CAN module 1 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
24
CAN0
R/W
0
CAN0 Reset Control
When this bit is set, CAN module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
23:21
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
20
PWM
R/W
0
PWM Reset Control
When this bit is set, PWM module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
19:18
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
294
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
17
ADC1
R/W
0
Description
ADC1 Reset Control
When this bit is set, ADC module 1 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
16
ADC0
R/W
0
ADC0 Reset Control
When this bit is set, ADC module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
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
WDT0
R/W
0
WDT0 Reset Control
When this bit is set, Watchdog Timer module 0 is reset. All internal data
is lost and the registers are returned to their reset states. This bit must
be manually cleared after being set.
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.
July 03, 2014
295
Texas Instruments-Production Data
System Control
Register 37: Software Reset Control 1 (SRCR1), offset 0x044
This register allows individual modules to be reset. 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
Type
Reset
Type
Reset
31
30
29
28
27
26
25
24
reserved
EPI0
reserved
I2S0
reserved
COMP2
COMP1
COMP0
RO
0
R/W
0
RO
0
R/W
0
RO
0
R/W
0
R/W
0
15
14
13
12
11
10
reserved
I2C1
reserved
I2C0
RO
0
R/W
0
RO
0
R/W
0
reserved
RO
0
RO
0
23
22
21
20
19
18
17
16
R/W
0
RO
0
RO
0
RO
0
RO
0
TIMER3
TIMER2
TIMER1
TIMER0
R/W
0
R/W
0
R/W
0
R/W
0
9
8
7
6
5
4
3
2
1
0
QEI1
QEI0
R/W
0
R/W
0
SSI1
SSI0
reserved
UART2
UART1
UART0
R/W
0
R/W
0
RO
0
R/W
0
R/W
0
R/W
0
reserved
reserved
RO
0
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
EPI0
R/W
0
EPI0 Reset Control
When this bit is set, EPI module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
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
I2S0
R/W
0
I2S0 Reset Control
When this bit is set, I2S module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
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
Analog Comp 2 Reset Control
When this bit is set, Analog Comparator module 2 is reset. All internal
data is lost and the registers are returned to their reset states. This bit
must be manually cleared after being set.
25
COMP1
R/W
0
Analog Comp 1 Reset Control
When this bit is set, Analog Comparator module 1 is reset. All internal
data is lost and the registers are returned to their reset states. This bit
must be manually cleared after being set.
24
COMP0
R/W
0
Analog Comp 0 Reset Control
When this bit is set, Analog Comparator module 0 is reset. All internal
data is lost and the registers are returned to their reset states. This bit
must be manually cleared after being set.
296
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
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
Timer 3 Reset Control
Timer 3 Reset Control. When this bit is set, General-Purpose Timer
module 3 is reset. All internal data is lost and the registers are returned
to their reset states. This bit must be manually cleared after being set.
18
TIMER2
R/W
0
Timer 2 Reset Control
When this bit is set, General-Purpose Timer module 2 is reset. All internal
data is lost and the registers are returned to their reset states. This bit
must be manually cleared after being set.
17
TIMER1
R/W
0
Timer 1 Reset Control
When this bit is set, General-Purpose Timer module 1 is reset. All internal
data is lost and the registers are returned to their reset states. This bit
must be manually cleared after being set.
16
TIMER0
R/W
0
Timer 0 Reset Control
When this bit is set, General-Purpose Timer module 0 is reset. All internal
data is lost and the registers are returned to their reset states. This bit
must be manually cleared after being set.
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
I2C1 Reset Control
When this bit is set, I2C module 1 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
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
I2C0 Reset Control
When this bit is set, I2C module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
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
QEI1
R/W
0
QEI1 Reset Control
When this bit is set, QEI module 1 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
8
QEI0
R/W
0
QEI0 Reset Control
When this bit is set, QEI module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
July 03, 2014
297
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
Description
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
SSI1
R/W
0
SSI1 Reset Control
When this bit is set, SSI module 1 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
4
SSI0
R/W
0
SSI0 Reset Control
When this bit is set, SSI module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
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
UART2 Reset Control
When this bit is set, UART module 2 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
1
UART1
R/W
0
UART1 Reset Control
When this bit is set, UART module 1 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
0
UART0
R/W
0
UART0 Reset Control
When this bit is set, UART module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
298
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 38: Software Reset Control 2 (SRCR2), offset 0x048
This register allows individual modules to be reset. 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
27
26
25
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
RO
0
RO
0
24
23
22
21
20
19
18
17
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
8
7
6
5
4
3
2
1
0
GPIOJ
GPIOH
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
R/W
0
R/W
0
reserved
Type
Reset
reserved
Type
Reset
RO
0
RO
0
UDMA
R/W
0
reserved
RO
0
RO
0
16
USB0
Bit/Field
Name
Type
Reset
Description
31:17
reserved
RO
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
16
USB0
R/W
0
USB0 Reset Control
When this bit is set, USB module 0 is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
15:14
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
UDMA
R/W
0
Micro-DMA Reset Control
When this bit is set, uDMA module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
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
GPIOJ
R/W
0
Port J Reset Control
When this bit is set, Port J module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
7
GPIOH
R/W
0
Port H Reset Control
When this bit is set, Port H module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
6
GPIOG
R/W
0
Port G Reset Control
When this bit is set, Port G module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
July 03, 2014
299
Texas Instruments-Production Data
System Control
Bit/Field
Name
Type
Reset
5
GPIOF
R/W
0
Description
Port F Reset Control
When this bit is set, Port F module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
4
GPIOE
R/W
0
Port E Reset Control
When this bit is set, Port E module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
3
GPIOD
R/W
0
Port D Reset Control
When this bit is set, Port D module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
2
GPIOC
R/W
0
Port C Reset Control
When this bit is set, Port C module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
1
GPIOB
R/W
0
Port B Reset Control
When this bit is set, Port B module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
0
GPIOA
R/W
0
Port A Reset Control
When this bit is set, Port A module is reset. All internal data is lost and
the registers are returned to their reset states. This bit must be manually
cleared after being set.
300
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
6
Internal Memory
The LM3S5791 microcontroller comes with 64 KB of bit-banded SRAM, internal ROM,and 128 KB
of Flash memory. The Flash memory controller provides a user-friendly interface, making Flash
memory programming a simple task. Flash memory protection can be applied to the Flash memory
on a 2-KB block basis.
6.1
Block Diagram
Figure 6-1 on page 301 illustrates the internal memory blocks and control logic. The dashed boxes
in the figure indicate registers residing in the System Control module.
Figure 6-1. Internal Memory Block Diagram
ROM Control
ROM Array
RMCTL
Flash Control
Icode Bus
Cortex-M3
FMA
FMD
FMC
FCRIS
FCIM
FCMISC
Dcode Bus
Flash Array
System
Bus
Flash Write Buffer
FMC2
FWBVAL
FWBn
32 words
Flash Protection
Bridge
FMPREn
FMPRE
FMPPEn
FMPPE
User
Registers
Flash
Timing
BOOTCFG
USECRL
USER_REG0
USER_REG1
USER_REG2
USER_REG3
SRAM Array
6.2
Functional Description
This section describes the functionality of the SRAM, ROM, and Flash memories.
Note:
The μDMA controller can transfer data to and from the on-chip SRAM. However, because
the Flash memory and ROM are located on a separate internal bus, it is not possible to
transfer data from the Flash memory or ROM with the μDMA controller.
July 03, 2014
301
Texas Instruments-Production Data
Internal Memory
6.2.1
SRAM
®
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 provides
bit-banding technology in the 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. The bit-band base is located at address 0x2200.0000.
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, see “Bit-Banding” on page 99.
Note:
6.2.2
The SRAM is implemented using two 32-bit wide SRAM banks (separate SRAM arrays).
The banks are partitioned such that one bank contains all even words (the even bank) and
the other contains all odd words (the odd bank). A write access that is followed immediately
by a read access to the same bank incurs a stall of a single clock cycle. However, a write
to one bank followed by a read of the other bank can occur in successive clock cycles
without incurring any delay.
ROM
The internal ROM of the Stellaris device is located at address 0x0100.0000 of the device memory
map. Detailed information on the ROM contents can be found in the Stellaris® ROM User’s Guide.
The ROM contains the following components:
■ Stellaris Boot Loader and vector table
■ Stellaris Peripheral Driver Library (DriverLib) release for product-specific peripherals and interfaces
■ Advanced Encryption Standard (AES) cryptography tables
■ Cyclic Redundancy Check (CRC) error detection functionality
The boot loader is used as an initial program loader (when the Flash memory is empty) as well as
an application-initiated firmware upgrade mechanism (by calling back to the boot loader). The
Peripheral Driver Library APIs in ROM can be called by applications, reducing Flash memory
requirements and freeing the Flash memory to be used for other purposes (such as additional
features in the application). Advance Encryption Standard (AES) is a publicly defined encryption
standard used by the U.S. Government and Cyclic Redundancy Check (CRC) is a technique to
validate a span of data has the same contents as when previously checked.
6.2.2.1
Boot Loader Overview
The Stellaris Boot Loader is used to download code to the Flash memory of a device without the
use of a debug interface. When the core is reset, the user has the opportunity to direct the core to
execute the ROM Boot Loader or the application in Flash memory by using any GPIO signal in Ports
A-H as configured in the Boot Configuration (BOOTCFG) register.
302
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
At reset, the ROM is mapped over the Flash memory so that the ROM boot sequence is always
executed. The boot sequence executed from ROM is as follows:
1. The BA bit (below) is cleared such that ROM is mapped to 0x01xx.xxxx and Flash memory is
mapped to address 0x0.
2. The BOOTCFG register is read. If the EN bit is clear, the status of the specified GPIO pin is
compared with the specified polarity. If the status matches the specified polarity, the ROM is
mapped to address 0x0000.0000 and execution continues out of the ROM Boot Loader.
3. If the status doesn't match the specified polarity, the data at address 0x0000.0004 is read, and
if the data at this address is 0xFFFF.FFFF, the ROM is mapped to address 0x0000.0000 and
execution continues out of the ROM Boot Loader.
4. If there is data at address 0x0000.0004 that is not 0xFFFF.FFFF, the stack pointer (SP) is loaded
from Flash memory at address 0x0000.0000 and the program counter (PC) is loaded from
address 0x0000.0004. The user application begins executing.
The boot loader uses a simple packet interface to provide synchronous communication with the
device. The speed of the boot loader is determined by the internal oscillator (PIOSC) frequency as
it does not enable the PLL. The following serial interfaces can be used:
■ UART0
■ SSI0
■ I2C0
For simplicity, both the data format and communication protocol are identical for all serial interfaces.
Note:
The Flash-memory-resident version of the Boot Loader also supports CAN and USB.
See the Stellaris® Boot Loader User's Guide for information on the boot loader software.
6.2.2.2
Stellaris Peripheral Driver Library
The Stellaris Peripheral Driver Library contains a file called driverlib/rom.h that assists with
calling the peripheral driver library functions in the ROM. The detailed description of each function
is available in the Stellaris® ROM User’s Guide. See the "Using the ROM" chapter of the Stellaris®
Peripheral Driver Library User's Guide for more details on calling the ROM functions and using
driverlib/rom.h.
A table at the beginning of the ROM points to the entry points for the APIs that are provided in the
ROM. Accessing the API through these tables provides scalability; while the API locations may
change in future versions of the ROM, the API tables will not. The tables are split into two levels;
the main table contains one pointer per peripheral which points to a secondary table that contains
one pointer per API that is associated with that peripheral. The main table is located at 0x0100.0010,
right after the Cortex-M3 vector table in the ROM.
DriverLib functions are described in detail in the Stellaris® Peripheral Driver Library User's Guide.
Additional APIs are available for graphics and USB functions, but are not preloaded into ROM. The
Stellaris Graphics Library provides a set of graphics primitives and a widget set for creating graphical
user interfaces on Stellaris microcontroller-based boards that have a graphical display (for more
information, see the Stellaris® Graphics Library User's Guide). The Stellaris USB Library is a set
of data types and functions for creating USB Device, Host or On-The-Go (OTG) applications on
July 03, 2014
303
Texas Instruments-Production Data
Internal Memory
Stellaris microcontroller-based boards (for more information, see the Stellaris® USB Library User's
Guide).
6.2.2.3
Advanced Encryption Standard (AES) Cryptography Tables
AES is a strong encryption method with reasonable performance and size. AES is fast in both
hardware and software, is fairly easy to implement, and requires little memory. AES is ideal for
applications that can use pre-arranged keys, such as setup during manufacturing or configuration.
Four data tables used by the XySSL AES implementation are provided in the ROM. The first is the
forward S-box substitution table, the second is the reverse S-box substitution table, the third is the
forward polynomial table, and the final is the reverse polynomial table. See the Stellaris® ROM
User’s Guide for more information on AES.
6.2.2.4
Cyclic Redundancy Check (CRC) Error Detection
The CRC technique can be used to validate correct receipt of messages (nothing lost or modified
in transit), to validate data after decompression, to validate that Flash memory contents have not
been changed, and for other cases where the data needs to be validated. A CRC is preferred over
a simple checksum (e.g. XOR all bits) because it catches changes more readily. See the Stellaris®
ROM User’s Guide for more information on CRC.
6.2.3
Flash Memory
At system clock speeds of 50 MHz and below, the Flash memory is read in a single cycle. The Flash
memory is organized as a set of 1-KB blocks that can be individually erased. An individual 32-bit
word can be programmed to change bits from 1 to 0. In addition, a write buffer provides the ability
to concurrently program 32 continuous words in Flash memory. Erasing a block causes the entire
contents of the block to be reset to all 1s. The 1-KB blocks are paired into sets 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.
Caution – The Stellaris Flash memory array has ECC which uses a test port into the Flash memory to
continually scan the array for ECC errors and to correct any that are detected. This operation is
transparent to the microcontroller. The BIST must scan the entire memory array occasionally to ensure
integrity, taking about five minutes to do so. In systems where the microcontroller is frequently powered
for less than five minutes, power should be removed from the microcontroller in a controlled manner
to ensure proper operation. Software can request permission to power down the part using the USDREQ
bit in the Flash Control (FCTL) register and wait to receive an acknowledge from the USDACK bit prior
to removing power. If the microcontroller is powered down using this controlled method, the BIST
engine keeps track of where it was in the memory array and it always scans the complete array after
any aggregate of five minutes powered-on, regardless of the number of intervening power cycles. If the
microcontroller is powered down before five minutes of being powered up, BIST starts again from
wherever it left off before the last controlled power-down or from 0 if there never was a controlled
power down. An occasional short power down is not a concern, but the microcontroller should not
always be powered down frequently in an uncontrolled manner. The microcontroller can be power-cycled
as frequently as necessary if it is powered-down in a controlled manner.
6.2.3.1
Prefetch Buffer
The Flash memory controller has a prefetch buffer that is automatically used when the CPU frequency
is greater than 50 MHz. In this mode, the Flash memory operates at half of the system clock. The
304
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
prefetch buffer fetches two 32-bit words per clock allowing instructions to be fetched with no wait
states while code is executing linearly. The fetch buffer includes a branch speculation mechanism
that recognizes a branch and avoids extra wait states by not reading the next word pair. Also, short
loop branches often stay in the buffer. As a result, some branches can be executed with no wait
states. Other branches incur a single wait state.
6.2.3.2
Flash Memory Protection
The user is provided two forms of Flash memory protection per 2-KB Flash memory block in two
pairs of 32-bit wide registers. The policy for each protection form is controlled by individual bits (per
policy per block) in the FMPPEn and FMPREn registers.
■ Flash Memory Protection Program Enable (FMPPEn): If a bit is set, the corresponding block
may be programmed (written) or erased. If a bit is cleared, the corresponding block may not be
changed.
■ Flash Memory Protection Read Enable (FMPREn): If a bit is set, the corresponding block may
be executed or read by software or debuggers. If a bit is cleared, the corresponding block may
only be executed, and contents of the memory block are prohibited from being read as data.
The policies may be combined as shown in Table 6-1 on page 305.
Table 6-1. Flash Memory Protection Policy Combinations
FMPPEn
FMPREn
0
0
Protection
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.
A Flash memory access that attempts to read a read-protected block (FMPREn bit is set) is prohibited
and generates a bus fault. A Flash memory access that attempts to program or erase a
program-protected block (FMPPEn bit is set) is prohibited and can optionally generate an interrupt
(by setting the AMASK bit in the Flash Controller Interrupt Mask (FCIM) register) to alert software
developers of poorly behaving software during the development and debug phases. Note that if a
FMPREn bit is cleared, all read accesses to the Flash memory block are disallowed, including any
data accesses. Care must be taken not to store required data in a Flash memory block that has the
associated FMPREn bit cleared.
The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented
banks. These settings create a policy of open access and programmability. The register bits may
be changed by clearing the specific register bit. The changes are effective immediately, but 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 any type of reset
sequence. The changes are committed using the Flash Memory Control (FMC) register. Details
on programming these bits are discussed in “Non-Volatile Register Programming” on page 308.
6.2.3.3
Interrupts
The Flash memory controller can generate interrupts when the following conditions are observed:
July 03, 2014
305
Texas Instruments-Production Data
Internal Memory
■ Programming Interrupt - signals when a program or erase action is complete.
■ Access Interrupt - signals when a program or erase action has been attempted on a 2-kB block
of memory that is protected by its corresponding FMPPEn bit.
The interrupt events that can trigger a controller-level interrupt are defined in the Flash Controller
Masked Interrupt Status (FCMIS) register (see page 317) by setting the corresponding MASK bits.
If interrupts are not used, the raw interrupt status is always visible via the Flash Controller Raw
Interrupt Status (FCRIS) register (see page 316).
Interrupts are always cleared (for both the FCMIS and FCRIS registers) by writing a 1 to the
corresponding bit in the Flash Controller Masked Interrupt Status and Clear (FCMISC) register
(see page 318).
6.2.3.4
Flash Memory Programming
The Stellaris devices provide a user-friendly interface for Flash memory programming. All
erase/program operations are handled via three registers: Flash Memory Address (FMA), Flash
Memory Data (FMD), and Flash Memory Control (FMC). Note that if the debug capabilities of the
microcontroller have been deactivated, resulting in a "locked" state, a recovery sequence must be
performed in order to reactivate the debug module. See “Recovering a "Locked"
Microcontroller” on page 190.
During a Flash memory operation (write, page erase, or mass erase) access to the Flash memory
is inhibited. As a result, instruction and literal fetches are held off until the Flash memory operation
is complete. If instruction execution is required during a Flash memory operation, the code that is
executing must be placed in SRAM and executed from there while the flash operation is in progress.
Caution – The Flash memory is divided into sectors of electrically separated address ranges of 4 KB
each, aligned on 4 KB boundaries. Erase/program operations on a 1-KB page have an electrical effect
on the other three 1-KB pages within the sector. A specific 1-KB page must be erased after 6 total
erase/program cycles occur to the other pages within its 4-KB sector. The following sequence of operations
on a 4-KB sector of Flash memory (Page 0..3) provides an example:
■ Page 3 is erase and programmed with values.
■ Page 0, Page 1, and Page 2 are erased and then programmed with values. At this point Page 3 has
been affected by 3 erase/program cycles.
■ Page 0, Page 1, and Page 2 are again erased and then programmed with values. At this point Page
3 has been affected by 6 erase/program cycles.
■ If the contents of Page 3 must continue to be valid, Page 3 must be erased and reprogrammed before
any other page in this sector has another erase or program operation.
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 memory 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.
306
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Important: To ensure proper operation, two writes to the same word must be separated by an
ERASE. The following two sequences are allowed:
■ ERASE -> PROGRAM value -> PROGRAM 0x0000.0000
■ ERASE -> PROGRAM value -> ERASE
The following sequence is NOT allowed:
■ ERASE -> PROGRAM value -> PROGRAM value
To perform an erase of a 1-KB page
1. Write the page address to the FMA register.
2. Write the Flash memory 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 or, alternatively, enable the programming
interrupt using the PMASK bit in the FCIM register.
To perform a mass erase of the Flash memory
1. Write the Flash memory 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 or, alternatively, enable the programming
interrupt using the PMASK bit in the FCIM register.
6.2.3.5
32-Word Flash Memory Write Buffer
A 32-word write buffer provides the capability to perform faster write accesses to the Flash memory
by concurrently programing 32 words with a single buffered Flash memory write operation. The
buffered Flash memory write operation takes the same amount of time as the single word write
operation controlled by bit 0 in the FMC register. The data for the buffered write is written to the
Flash Write Buffer (FWBn) registers.
The registers are 32-word aligned with Flash memory, and therefore the register FWB0 corresponds
with the address in FMA where bits [6:0] of FMA are all 0. FWB1 corresponds with the address in
FMA + 0x4 and so on. Only the FWBn registers that have been updated since the previous buffered
Flash memory write operation are written. The Flash Write Buffer Valid (FWBVAL) register shows
which registers have been written since the last buffered Flash memory write operation. This register
contains a bit for each of the 32 FWBn registers, where bit[n] of FWBVAL corresponds to FWBn.
The FWBn register has been updated if the corresponding bit in the FWBVAL register is set.
To program 32 words with a single buffered Flash memory write operation
1. Write the source data to the FWBn registers.
2. Write the target address to the FMA register. This must be a 32-word aligned address (that is,
bits [6:0] in FMA must be 0s).
3. Write the Flash memory write key and the WRBUF bit (a value of 0xA442.0001) to the FMC2
register.
July 03, 2014
307
Texas Instruments-Production Data
Internal Memory
4. Poll the FMC2 register until the WRBUF bit is cleared or wait for the PMIS interrupt to be signaled.
6.2.3.6
Non-Volatile Register Programming
Note:
The Boot Configuration (BOOTCFG) register requires a POR before the committed
changes take effect.
This section discusses how to update the registers shown in Table 6-2 on page 309 that are resident
within the Flash memory itself. These registers exist in a separate space from the main Flash memory
array and are not affected by an ERASE or MASS ERASE operation. With the exception of the Boot
Configuration (BOOTCFG) register, the settings in these registers can be written, their functions
verified, and their values read back before they are committed, at which point they become
non-volatile. If a value in one of these registers has not been committed, any type of reset restores
the last committed value or the default value if the register has never been committed. Once the
register contents are committed, the only way to restore the factory default values is to perform the
sequence described in “Recovering a "Locked" Microcontroller” on page 190.
To write to a non-volatile register:
■ Bits can only be changed from 1 to 0.
■ For all registers except the BOOTCFG register, write the data to the register address provided
in the register description. For the BOOTCFG register, write the data to the FMD register.
■ The registers can be read to verify their contents. To verify what is to be stored in the BOOTCFG
register, read the FMD register. Reading the BOOTCFG register returns the previously committed
value or the default value if the register has never been committed.
■ The new values are effectively immediately for all registers except BOOTCFG, as the new value
for the register is not stored in the register until it has been committed.
■ Prior to committing the register value, any type of reset restores the last committed value or the
default value if the register has never been committed.
To commit a new value to a non-volatile register:
■ Write the data as described above.
■ Write to the FMA register the value shown in Table 6-2 on page 309.
■ Write the Flash memory write key and set the COMT bit in the FMC register. These values must
be written to the FMC register at the same time.
■ Committing a non-volatile register has the same timing as a write to regular Flash memory,
defined by TPROG, as shown in Table 25-16 on page 1255. Software can poll the COMT bit in the
FMC register to determine when the operation is complete, or an interrupt can be enabled by
setting the PMASK bit in the FCIM register.
■ When committing the BOOTCFG register, the INVDRIS bit in the FCRIS register is set if a bit
that has already been committed as a 0 is attempted to be committed as a 1.
■ Once the value has been committed, any type of reset has no effect on the register contents.
■ Changes to the BOOTCFG register are effective after the next reset.
308
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ The NW bit in the USER_REG0, USER_REG1, USER_REG2, USER_REG3, and BOOTCFG
registers is cleared when the register is committed. Once this bit is cleared, additional changes
to the register are not allowed.
Important: After being committed, these registers can only be restored to their factory default values
by performing the sequence described in “Recovering a "Locked"
Microcontroller” on page 190. The mass erase of the main Flash memory array caused
by the sequence is performed prior to restoring these registers.
Table 6-2. User-Programmable Flash Memory Resident Registers
Register to be Committed
6.3
FMA Value
Data Source
FMPRE0
0x0000.0000
FMPRE0
FMPRE1
0x0000.0002
FMPRE1
FMPPE0
0x0000.0001
FMPPE0
FMPPE1
0x0000.0003
FMPPE1
USER_REG0
0x8000.0000
USER_REG0
USER_REG1
0x8000.0001
USER_REG1
USER_REG2
0x8000.0002
USER_REG2
USER_REG3
0x8000.0003
USER_REG3
BOOTCFG
0x7510.0000
FMD
Register Map
Table 6-3 on page 309 lists the ROM Controller register and the Flash memory and control registers.
The offset listed is a hexadecimal increment to the register's address. The Flash memory register
offsets are relative to the Flash memory control base address of 0x400F.D000. The ROM and Flash
memory protection register offsets are relative to the System Control base address of 0x400F.E000.
Table 6-3. Flash Register Map
Offset
Name
Type
Reset
Description
See
page
Flash Memory Registers (Flash Control Offset)
0x000
FMA
R/W
0x0000.0000
Flash Memory Address
311
0x004
FMD
R/W
0x0000.0000
Flash Memory Data
312
0x008
FMC
R/W
0x0000.0000
Flash Memory Control
313
0x00C
FCRIS
RO
0x0000.0000
Flash Controller Raw Interrupt Status
316
0x010
FCIM
R/W
0x0000.0000
Flash Controller Interrupt Mask
317
0x014
FCMISC
R/W1C
0x0000.0000
Flash Controller Masked Interrupt Status and Clear
318
0x020
FMC2
R/W
0x0000.0000
Flash Memory Control 2
319
0x030
FWBVAL
R/W
0x0000.0000
Flash Write Buffer Valid
320
0x0F8
FCTL
R/W
0x0000.0000
Flash Control
321
0x100 0x17C
FWBn
R/W
0x0000.0000
Flash Write Buffer n
322
July 03, 2014
309
Texas Instruments-Production Data
Internal Memory
Table 6-3. Flash Register Map (continued)
Offset
Name
Reset
Description
See
page
R/W1C
-
ROM Control
323
Type
Memory Registers (System Control Offset)
0x0F0
RMCTL
0x130
FMPRE0
R/W
0xFFFF.FFFF
Flash Memory Protection Read Enable 0
324
0x200
FMPRE0
R/W
0xFFFF.FFFF
Flash Memory Protection Read Enable 0
324
0x134
FMPPE0
R/W
0xFFFF.FFFF
Flash Memory Protection Program Enable 0
325
0x400
FMPPE0
R/W
0xFFFF.FFFF
Flash Memory Protection Program Enable 0
325
0x1D0
BOOTCFG
R/W
0xFFFF.FFFE
Boot Configuration
326
0x1E0
USER_REG0
R/W
0xFFFF.FFFF
User Register 0
328
0x1E4
USER_REG1
R/W
0xFFFF.FFFF
User Register 1
329
0x1E8
USER_REG2
R/W
0xFFFF.FFFF
User Register 2
330
0x1EC
USER_REG3
R/W
0xFFFF.FFFF
User Register 3
331
0x204
FMPRE1
R/W
0xFFFF.FFFF
Flash Memory Protection Read Enable 1
332
0x208
FMPRE2
R/W
0x0000.0000
Flash Memory Protection Read Enable 2
333
0x20C
FMPRE3
R/W
0x0000.0000
Flash Memory Protection Read Enable 3
334
0x404
FMPPE1
R/W
0xFFFF.FFFF
Flash Memory Protection Program Enable 1
335
0x408
FMPPE2
R/W
0x0000.0000
Flash Memory Protection Program Enable 2
336
0x40C
FMPPE3
R/W
0x0000.0000
Flash Memory Protection Program Enable 3
337
6.4
Flash Memory Register Descriptions (Flash Control Offset)
This section lists and describes the Flash Memory registers, in numerical order by address offset.
Registers in this section are relative to the Flash control base address of 0x400F.D000.
310
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
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 CPU byte address
and specifies which block 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
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
24
23
22
21
20
19
18
17
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
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
reserved
Type
Reset
16
OFFSET
OFFSET
Type
Reset
Bit/Field
Name
Type
Reset
Description
31:17
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.
16:0
OFFSET
R/W
0x0
Address Offset
Address offset in Flash memory where operation is performed, except
for non-volatile registers (see “Non-Volatile Register
Programming” on page 308 for details on values for this field).
July 03, 2014
311
Texas Instruments-Production Data
Internal Memory
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 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
31:0
DATA
R/W
Reset
Description
0x0000.0000 Data Value
Data value for write operation.
312
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 3: Flash Memory Control (FMC), offset 0x008
When this register is written, the Flash memory controller initiates the appropriate access cycle for
the location specified by the Flash Memory Address (FMA) register (see page 311). If the access
is a write access, the data contained in the Flash Memory Data (FMD) register (see page 312) is
written to the specified address.
This register must be the final register written and initiates the memory operation. The four control
bits in the lower byte of this register are used to initiate memory operations.
Care must be taken not to set multiple control bits as the results of such an operation are
unpredictable.
Caution – If any of bits [15:4] are written to 1, the device may become inoperable. These bits should
always be written to 0. In all registers, the value of a reserved bit should be preserved across a
read-modify-write operation.
Flash Memory Control (FMC)
Base 0x400F.D000
Offset 0x008
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
COMT
MERASE
ERASE
WRITE
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
R/W
0
R/W
0
R/W
0
WRKEY
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
31:16
WRKEY
WO
0x0000
Description
Flash Memory Write Key
This field contains a write key, which is used to minimize the incidence
of accidental Flash memory writes. The value 0xA442 must be written
into this field for a Flash memory 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
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.
July 03, 2014
313
Texas Instruments-Production Data
Internal Memory
Bit/Field
Name
Type
Reset
3
COMT
R/W
0
Description
Commit Register Value
This bit is used to commit writes to Flash-memory-resident registers
and to monitor the progress of that process.
Value Description
1
Set this bit to commit (write) the register value to a
Flash-memory-resident register.
When read, a 1 indicates that the previous commit access is
not complete.
0
A write of 0 has no effect on the state of this bit.
When read, a 0 indicates that the previous commit access is
complete.
See “Non-Volatile Register Programming” on page 308 for more
information on programming Flash-memory-resident registers.
2
MERASE
R/W
0
Mass Erase Flash Memory
This bit is used to mass erase the Flash main memory and to monitor
the progress of that process.
Value Description
1
Set this bit to erase the Flash main memory.
When read, a 1 indicates that the previous mass erase access
is not complete.
0
A write of 0 has no effect on the state of this bit.
When read, a 0 indicates that the previous mass erase access
is complete.
For information on erase time, see “Flash Memory” on page 1255.
1
ERASE
R/W
0
Erase a Page of Flash Memory
This bit is used to erase a page of Flash memory and to monitor the
progress of that process.
Value Description
1
Set this bit to erase the Flash memory page specified by the
contents of the FMA register.
When read, a 1 indicates that the previous page erase access
is not complete.
0
A write of 0 has no effect on the state of this bit.
When read, a 0 indicates that the previous page erase access
is complete.
For information on erase time, see “Flash Memory” on page 1255.
314
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
0
WRITE
R/W
0
Description
Write a Word into Flash Memory
This bit is used to write a word into Flash memory and to monitor the
progress of that process.
Value Description
1
Set this bit to write the data stored in the FMD register into the
Flash memory location specified by the contents of the FMA
register.
When read, a 1 indicates that the write update access is not
complete.
0
A write of 0 has no effect on the state of this bit.
When read, a 0 indicates that the previous write update access
is complete.
For information on programming time, see “Flash Memory” on page 1255.
July 03, 2014
315
Texas Instruments-Production Data
Internal Memory
Register 4: Flash Controller Raw Interrupt Status (FCRIS), offset 0x00C
This register indicates that the Flash memory controller has an interrupt condition. An interrupt is
sent to the interrupt controller only 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
31:2
reserved
RO
0x0000.000
1
PRIS
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.
Programming Raw Interrupt Status
This bit provides status on programming cycles which are write or erase
actions generated through the FMC or FMC2 register bits (see page 313
and page 319).
Value Description
1
The programming or erase cycle has completed.
0
The programming or erase cycle has not completed.
This status is sent to the interrupt controller when the PMASK bit in the
FCIM register is set.
This bit is cleared by writing a 1 to the PMISC bit in the FCMISC register.
0
ARIS
RO
0
Access Raw Interrupt Status
Value Description
1
A program or erase action was attempted on a block of Flash
memory that contradicts the protection policy for that block as
set in the FMPPEn registers.
0
No access has tried to improperly program or erase the Flash
memory.
This status is sent to the interrupt controller when the AMASK bit in the
FCIM register is set.
This bit is cleared by writing a 1 to the AMISC bit in the FCMISC register.
316
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 5: Flash Controller Interrupt Mask (FCIM), offset 0x010
This register controls whether the Flash memory 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
31:2
reserved
RO
0x0000.000
1
PMASK
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.
Programming Interrupt Mask
This bit controls the reporting of the programming raw interrupt status
to the interrupt controller.
Value Description
0
AMASK
R/W
0
1
An interrupt is sent to the interrupt controller when the PRIS bit
is set.
0
The PRIS interrupt is suppressed and not sent to the interrupt
controller.
Access Interrupt Mask
This bit controls the reporting of the access raw interrupt status to the
interrupt controller.
Value Description
1
An interrupt is sent to the interrupt controller when the ARIS bit
is set.
0
The ARIS interrupt is suppressed and not sent to the interrupt
controller.
July 03, 2014
317
Texas Instruments-Production Data
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
Bit/Field
Name
Type
Reset
31:2
reserved
RO
0x0000.000
1
PMISC
R/W1C
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
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.
Programming Masked Interrupt Status and Clear
Value Description
1
When read, a 1 indicates that an unmasked interrupt was
signaled because a programming cycle completed.
Writing a 1 to this bit clears PMISC and also the PRIS bit in the
FCRIS register (see page 316).
0
When read, a 0 indicates that a programming cycle complete
interrupt has not occurred.
A write of 0 has no effect on the state of this bit.
0
AMISC
R/W1C
0
Access Masked Interrupt Status and Clear
Value Description
1
When read, a 1 indicates that an unmasked interrupt was
signaled because a program or erase action was attempted on
a block of Flash memory that contradicts the protection policy
for that block as set in the FMPPEn registers.
Writing a 1 to this bit clears AMISC and also the ARIS bit in the
FCRIS register (see page 316).
0
When read, a 0 indicates that no improper accesses have
occurred.
A write of 0 has no effect on the state of this bit.
318
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 7: Flash Memory Control 2 (FMC2), offset 0x020
When this register is written, the Flash memory controller initiates the appropriate access cycle for
the location specified by the Flash Memory Address (FMA) register (see page 311). If the access
is a write access, the data contained in the Flash Write Buffer (FWB) registers is written.
This register must be the final register written as it initiates the memory operation.
Flash Memory Control 2 (FMC2)
Base 0x400F.D000
Offset 0x020
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
8
7
6
5
4
3
2
1
WRKEY
Type
Reset
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
WO
0
15
14
13
12
11
10
9
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:16
WRKEY
WO
0x0000
RO
0
0
WRBUF
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W
0
Description
Flash Memory Write Key
This field contains a write key, which is used to minimize the incidence
of accidental Flash memory writes. The value 0xA442 must be written
into this field for a write to occur. Writes to the FMC2 register without
this WRKEY value are ignored. A read of this field returns the value 0.
15:1
reserved
RO
0x000
0
WRBUF
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.
Buffered Flash Memory Write
This bit is used to start a buffered write to Flash memory.
Value Description
1
Set this bit to write the data stored in the FWBn registers to the
location specified by the contents of the FMA register.
When read, a 1 indicates that the previous buffered Flash
memory write access is not complete.
0
A write of 0 has no effect on the state of this bit.
When read, a 0 indicates that the previous buffered Flash
memory write access is complete.
For information on programming time, see “Flash Memory” on page 1255.
July 03, 2014
319
Texas Instruments-Production Data
Internal Memory
Register 8: Flash Write Buffer Valid (FWBVAL), offset 0x030
This register provides a bitwise status of which FWBn registers have been written by the processor
since the last write of the Flash memory write buffer. The entries with a 1 are written on the next
write of the Flash memory write buffer. This register is cleared after the write operation by hardware.
A protection violation on the write operation also clears this status.
Software can program the same 32 words to various Flash memory locations by setting the FWB[n]
bits after they are cleared by the write operation. The next write operation then uses the same data
as the previous one. In addition, if a FWBn register change should not be written to Flash memory,
software can clear the corresponding FWB[n] bit to preserve the existing data when the next write
operation occurs.
Flash Write Buffer Valid (FWBVAL)
Base 0x400F.D000
Offset 0x030
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FWB[n]
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
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
FWB[n]
Type
Reset
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
31:0
FWB[n]
R/W
0x0
R/W
0
Description
Flash Memory Write Buffer
Value Description
1
The corresponding FWBn register has been updated since the
last buffer write operation and is ready to be written to Flash
memory.
0
The corresponding FWBn register has no new data to be written.
Bit 0 corresponds to FWB0, offset 0x100, and bit 31 corresponds to
FWB31, offset 0x13C.
320
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 9: Flash Control (FCTL), offset 0x0F8
This register is used to ensure that the microcontroller is powered down in a controlled fashion in
systems where power is cycled more frequently than once every five minutes. The USDREQ bit
should be set to indicate that power is going to be turned off. Software should poll the USDACK bit
to determine when it is acceptable to power down.
Flash Control (FCTL)
Base 0x400F.D000
Offset 0x0F8
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
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
Bit/Field
Name
Type
Reset
31:2
reserved
RO
0x0000.000
1
USDACK
RO
0
USDACK USDREQ
RO
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.
User Shut Down Acknowledge
Value Description
1
The microcontroller can be powered down.
0
The microcontroller cannot yet be powered down.
This bit should be set within 50 ms of setting the USDREQ bit.
0
USDREQ
R/W
0
User Shut Down Request
Value Description
1
Requests permission to power down the microcontroller.
0
No effect.
July 03, 2014
321
Texas Instruments-Production Data
Internal Memory
Register 10: Flash Write Buffer n (FWBn), offset 0x100 - 0x17C
These 32 registers hold the contents of the data to be written into the Flash memory on a buffered
Flash memory write operation. The offset selects one of the 32-bit registers. Only FWBn registers
that have been updated since the preceding buffered Flash memory write operation are written into
the Flash memory, so it is not necessary to write the entire bank of registers in order to write 1 or
2 words. The FWBn registers are written into the Flash memory with the FWB0 register corresponding
to the address contained in FMA. FWB1 is written to the address FMA+0x4 etc. Note that only data
bits that are 0 result in the Flash memory being modified. A data bit that is 1 leaves the content of
the Flash memory bit at its previous value.
Flash Write Buffer n (FWBn)
Base 0x400F.D000
Offset 0x100 - 0x17C
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
31:0
DATA
R/W
Reset
Description
0x0000.0000 Data
Data to be written into the Flash memory.
6.5
Memory Register Descriptions (System Control Offset)
The remainder of this section lists and describes the registers that reside in the System Control
address space, in numerical order by address offset. Registers in this section are relative to the
System Control base address of 0x400F.E000.
322
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 11: ROM Control (RMCTL), offset 0x0F0
This register provides control of the ROM controller state. This register offset is relative to the System
Control base address of 0x400F.E000.
At reset, the ROM is mapped over the Flash memory so that the ROM boot sequence is always
executed. The boot sequence executed from ROM is as follows:
1. The BA bit (below) is cleared such that ROM is mapped to 0x01xx.xxxx and Flash memory is
mapped to address 0x0.
2. The BOOTCFG register is read. If the EN bit is clear, the status of the specified GPIO pin is
compared with the specified polarity. If the status matches the specified polarity, the ROM is
mapped to address 0x0000.0000 and execution continues out of the ROM Boot Loader.
3. If the status doesn't match the specified polarity, the data at address 0x0000.0004 is read, and
if the data at this address is 0xFFFF.FFFF, the ROM is mapped to address 0x0000.0000 and
execution continues out of the ROM Boot Loader.
4. If there is data at address 0x0000.0004 that is not 0xFFFF.FFFF, the stack pointer (SP) is loaded
from Flash memory at address 0x0000.0000 and the program counter (PC) is loaded from
address 0x0000.0004. The user application begins executing.
ROM Control (RMCTL)
Base 0x400F.E000
Offset 0x0F0
Type R/W1C, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
reserved
Type
Reset
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
RO
0
8
7
6
5
4
3
2
1
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:1
reserved
RO
0x0000.000
0
BA
R/W1C
1
RO
0
0
BA
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
R/W1C
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.
Boot Alias
Value Description
1
The microcontroller's ROM appears at address 0x0.
0
The Flash memory is at address 0x0.
This bit is cleared by writing a 1 to this bit position.
July 03, 2014
323
Texas Instruments-Production Data
Internal Memory
Register 12: 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). Flash memory up to a total of 64 KB is controlled by this register. Other FMPREn
registers (if any) provide protection for other 64K blocks. 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. The reset value shown only applies to power-on reset; any other type of reset does
not affect this register. Once committed, the only way to restore the factory default value of this
register is to perform the sequence detailed in “Recovering a "Locked" Microcontroller” on page 190.
For additional information, see “Flash Memory Protection” on page 305.
Flash Memory Protection Read Enable 0 (FMPRE0)
Base 0x400F.E000
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
R/W
1
Bit/Field
Name
Type
31:0
READ_ENABLE
R/W
R/W
1
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Read Enable
Configures 2-KB flash blocks to be read or executed only. The policies
may be combined as shown in Table 6-1 on page 305.
Value
Description
0xFFFFFFFF Bits [31:0] each enable protection on a 2-KB block of
Flash memory up to the total of 64 KB.
324
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 13: 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). Flash memory up to a total of 64 KB is controlled by this register. Other FMPPEn
registers (if any) provide protection for other 64K blocks. 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. The reset value shown only applies to power-on reset; any other type of reset does
not affect this register. Once committed, the only way to restore the factory default value of this
register is to perform the sequence detailed in “Recovering a "Locked" Microcontroller” on page 190.
For additional information, see “Flash Memory Protection” on page 305.
Flash Memory Protection Program Enable 0 (FMPPE0)
Base 0x400F.E000
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
R/W
1
Bit/Field
Name
Type
31:0
PROG_ENABLE
R/W
R/W
1
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Programming Enable
Configures 2-KB flash blocks to be execute only. The policies may be
combined as shown in Table 6-1 on page 305.
Value
Description
0xFFFFFFFF Bits [31:0] each enable protection on a 2-KB block of
Flash memory up to the total of 64 KB.
July 03, 2014
325
Texas Instruments-Production Data
Internal Memory
Register 14: Boot Configuration (BOOTCFG), offset 0x1D0
Note:
Offset is relative to System Control base address of 0x400FE000.
This register provides configuration of a GPIO pin to enable the ROM Boot Loader as well as a
write-once mechanism to disable external debugger access to the device. Upon reset, the user has
the opportunity to direct the core to execute the ROM Boot Loader or the application in Flash memory
by using any GPIO signal from Ports A-H as configured by the bits in this register. If the EN bit is
set or the specified pin does not have the required polarity, the system control module checks
address 0x000.0004 to see if the Flash memory has a valid reset vector. If the data at address
0x0000.0004 is 0xFFFF.FFFF, then it is assumed that the Flash memory has not yet been
programmed, and the core executes the ROM Boot Loader. 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. Clearing the
DBG1 bit disables any external debugger access to the device permanently, starting with the next
power-up cycle of the device. The NW bit (bit 31) indicates that the register has not yet been
committed and is controlled through hardware to ensure that the register is only committed once.
Prior to being committed, bits can only be changed from 1 to 0. The reset value shown only applies
to power-on reset; any other type of reset does not affect this register. Once committed, the only
way to restore the factory default value of this register is to perform the sequence detailed in
“Recovering a "Locked" Microcontroller” on page 190.
Boot Configuration (BOOTCFG)
Base 0x400F.E000
Offset 0x1D0
Type R/W, reset 0xFFFF.FFFE
31
30
29
28
27
26
25
24
NW
Type
Reset
R/W
1
15
RO
1
RO
1
RO
1
14
13
12
PORT
Type
Reset
R/W
1
23
22
21
20
19
18
17
16
RO
1
RO
1
reserved
R/W
1
RO
1
RO
1
11
10
PIN
R/W
1
R/W
1
R/W
1
R/W
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
7
6
5
4
3
2
9
8
POL
EN
R/W
1
R/W
1
reserved
RO
1
Bit/Field
Name
Type
Reset
Description
31
NW
R/W
1
Not Written
RO
1
RO
1
RO
1
RO
1
RO
1
1
0
DBG1
DBG0
R/W
1
R/W
0
When set, this bit indicates that this 32-bit register has not been
committed. When clear, this bit specifies that this register has been
committed and may not be committed again.
30:16
reserved
RO
0x7FFF
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
326
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
15:13
PORT
R/W
0x7
Description
Boot GPIO Port
This field selects the port of the GPIO port pin that enables the ROM
boot loader at reset.
Value Description
12:10
PIN
R/W
0x7
0x0
Port A
0x1
Port B
0x2
Port C
0x3
Port D
0x4
Port E
0x5
Port F
0x6
Port G
0x7
Port H
Boot GPIO Pin
This field selects the pin number of the GPIO port pin that enables the
ROM boot loader at reset.
Value Description
9
POL
R/W
0x1
0x0
Pin 0
0x1
Pin 1
0x2
Pin 2
0x3
Pin 3
0x4
Pin 4
0x5
Pin 5
0x6
Pin 6
0x7
Pin 7
Boot GPIO Polarity
When set, this bit selects a high level for the GPIO port pin to enable
the ROM boot loader at reset. When clear, this bit selects a low level
for the GPIO port pin.
8
EN
R/W
0x1
Boot GPIO Enable
Clearing this bit enables the use of a GPIO pin to enable the ROM Boot
Loader at reset. When this bit is set, the contents of address
0x0000.0004 are checked to see if the Flash memory has been
programmed. If the contents are not 0xFFFF.FFFF, the core executes
out of Flash memory. If the Flash has not been programmed, the core
executes out of ROM.
7:2
reserved
RO
0x3F
1
DBG1
R/W
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.
Debug Control 1
The DBG1 bit must be 1 and DBG0 must be 0 for debug to be available.
0
DBG0
R/W
0x0
Debug Control 0
The DBG1 bit must be 1 and DBG0 must be 0 for debug to be available.
July 03, 2014
327
Texas Instruments-Production Data
Internal Memory
Register 15: 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 committed
once. Bit 31 indicates that the register is available to be committed and is controlled through hardware
to ensure that the register is only committed once. Prior to being committed, bits can only be changed
from 1 to 0. The reset value shown only applies to power-on reset; any other type of reset does not
affect this register. 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. Once committed, the only way to restore
the factory default value of this register is to perform the sequence detailed in “Recovering a "Locked"
Microcontroller” on page 190.
User Register 0 (USER_REG0)
Base 0x400F.E000
Offset 0x1E0
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
NW
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
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
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
Bit/Field
Name
Type
Reset
Description
31
NW
R/W
1
Not Written
When set, this bit indicates that this 32-bit register has not been
committed. When clear, this bit specifies that this register has been
committed and may not be committed again.
30:0
DATA
R/W
0x7FFFFFFF User Data
Contains the user data value. This field is initialized to all 1s and can
only be committed once.
328
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 16: 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 0xFFFF.FFFF
31
30
29
28
27
26
25
24
NW
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
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
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
Bit/Field
Name
Type
Reset
Description
31
NW
R/W
1
Not Written
When set, this bit indicates that this 32-bit register has not been
committed. When clear, this bit specifies that this register has been
committed and may not be committed again.
30:0
DATA
R/W
0x7FFFFFFF User Data
Contains the user data value. This field is initialized to all 1s and can
only be committed once.
July 03, 2014
329
Texas Instruments-Production Data
Internal Memory
Register 17: User Register 2 (USER_REG2), offset 0x1E8
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 2 (USER_REG2)
Base 0x400F.E000
Offset 0x1E8
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
NW
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
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
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
Bit/Field
Name
Type
Reset
Description
31
NW
R/W
1
Not Written
When set, this bit indicates that this 32-bit register has not been
committed. When clear, this bit specifies that this register has been
committed and may not be committed again.
30:0
DATA
R/W
0x7FFFFFFF User Data
Contains the user data value. This field is initialized to all 1s and can
only be committed once.
330
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 18: User Register 3 (USER_REG3), offset 0x1EC
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 3 (USER_REG3)
Base 0x400F.E000
Offset 0x1EC
Type R/W, reset 0xFFFF.FFFF
31
30
29
28
27
26
25
24
NW
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
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
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
Bit/Field
Name
Type
Reset
Description
31
NW
R/W
1
Not Written
When set, this bit indicates that this 32-bit register has not been
committed. When clear, this bit specifies that this register has been
committed and may not be committed again.
30:0
DATA
R/W
0x7FFFFFFF User Data
Contains the user data value. This field is initialized to all 1s and can
only be committed once.
July 03, 2014
331
Texas Instruments-Production Data
Internal Memory
Register 19: 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). Flash memory up to a total of 64 KB is controlled by this register. Other FMPREn
registers (if any) provide protection for other 64K blocks. 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. The reset value shown only applies to power-on reset; any other type of reset does
not affect this register. Once committed, the only way to restore the factory default value of this
register is to perform the sequence detailed in “Recovering a "Locked" Microcontroller” on page 190.
If the Flash memory size on the device is less than 64 KB, this register usually reads as zeroes, but
software should not rely on these bits to be zero. For additional information, see “Flash Memory
Protection” on page 305.
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
R/W
1
Bit/Field
Name
Type
31:0
READ_ENABLE
R/W
R/W
1
Reset
R/W
1
R/W
1
Description
0xFFFFFFFF Flash Read Enable
Configures 2-KB flash blocks to be read or executed only. The policies
may be combined as shown in Table 6-1 on page 305.
Value
Description
0xFFFFFFFF Bits [31:0] each enable protection on a 2-KB block of
Flash memory in memory range from 65 to 128 KB.
332
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 20: 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). Flash memory up to a total of 64 KB is controlled by this register. Other FMPREn
registers (if any) provide protection for other 64K blocks. 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. The reset value shown only applies to power-on reset; any other type of reset does
not affect this register. Once committed, the only way to restore the factory default value of this
register is to perform the sequence detailed in “Recovering a "Locked" Microcontroller” on page 190.
If the Flash memory size on the device is less than 128 KB, this register usually reads as zeroes,
but software should not rely on these bits to be zero. For additional information, see “Flash Memory
Protection” on page 305.
Flash Memory Protection Read Enable 2 (FMPRE2)
Base 0x400F.E000
Offset 0x208
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
READ_ENABLE
Type
Reset
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
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
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
READ_ENABLE
Type
Reset
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
31:0
READ_ENABLE
R/W
R/W
0
Reset
R/W
0
R/W
0
Description
0x00000000 Flash Read Enable
Configures 2-KB flash blocks to be read or executed only. The policies
may be combined as shown in Table 6-1 on page 305.
Value
Description
0x00000000 Bits [31:0] each enable protection on a 2-KB block of
Flash memory in the range from 129 to 192 KB.
July 03, 2014
333
Texas Instruments-Production Data
Internal Memory
Register 21: 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). Flash memory up to a total of 64 KB is controlled by this register. Other FMPREn
registers (if any) provide protection for other 64K blocks. 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. The reset value shown only applies to power-on reset; any other type of reset does
not affect this register. Once committed, the only way to restore the factory default value of this
register is to perform the sequence detailed in “Recovering a "Locked" Microcontroller” on page 190.
If the Flash memory size on the device is less than 192 KB, this register usually reads as zeroes,
but software should not rely on these bits to be zero. For additional information, see “Flash Memory
Protection” on page 305.
Flash Memory Protection Read Enable 3 (FMPRE3)
Base 0x400F.E000
Offset 0x20C
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
READ_ENABLE
Type
Reset
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
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
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
READ_ENABLE
Type
Reset
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
31:0
READ_ENABLE
R/W
R/W
0
Reset
R/W
0
R/W
0
Description
0x00000000 Flash Read Enable
Configures 2-KB flash blocks to be read or executed only. The policies
may be combined as shown in Table 6-1 on page 305.
Value
Description
0x00000000 Bits [31:0] each enable protection on a 2-KB block of
Flash memory in the range from 193 to 256 KB.
334
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 22: 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). Flash memory up to a total of 64 KB is controlled by this register. Other FMPPEn
registers (if any) provide protection for other 64K blocks. 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. The reset value shown only applies to power-on reset; any other type of reset does
not affect this register. Once committed, the only way to restore the factory default value of this
register is to perform the sequence detailed in “Recovering a "Locked" Microcontroller” on page 190.
If the Flash memory size on the device is less than 64 KB, this register usually reads as zeroes, but
software should not rely on these bits to be zero. For additional information, see “Flash Memory
Protection” on page 305.
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 Flash Programming Enable
Configures 2-KB flash blocks to be execute only. The policies may be
combined as shown in Table 6-1 on page 305.
Value
Description
0xFFFFFFFF Bits [31:0] each enable protection on a 2-KB block of
Flash memory in memory range from 65 to 128 KB.
July 03, 2014
335
Texas Instruments-Production Data
Internal Memory
Register 23: 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). Flash memory up to a total of 64 KB is controlled by this register. Other FMPPEn
registers (if any) provide protection for other 64K blocks. 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. The reset value shown only applies to power-on reset; any other type of reset does
not affect this register. Once committed, the only way to restore the factory default value of this
register is to perform the sequence detailed in “Recovering a "Locked" Microcontroller” on page 190.
If the Flash memory size on the device is less than 128 KB, this register usually reads as zeroes,
but software should not rely on these bits to be zero. For additional information, see “Flash Memory
Protection” on page 305.
Flash Memory Protection Program Enable 2 (FMPPE2)
Base 0x400F.E000
Offset 0x408
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
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
PROG_ENABLE
Type
Reset
PROG_ENABLE
Type
Reset
Bit/Field
Name
Type
31:0
PROG_ENABLE
R/W
Reset
R/W
0
R/W
0
Description
0x00000000 Flash Programming Enable
Configures 2-KB flash blocks to be execute only. The policies may be
combined as shown in Table 6-1 on page 305.
Value
Description
0x00000000 Bits [31:0] each enable protection on a 2-KB block of
Flash memory in the range from 129 to 192 KB.
336
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 24: 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). Flash memory up to a total of 64 KB is controlled by this register. Other FMPPEn
registers (if any) provide protection for other 64K blocks. 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. The reset value shown only applies to power-on reset; any other type of reset does
not affect this register. Once committed, the only way to restore the factory default value of this
register is to perform the sequence detailed in “Recovering a "Locked" Microcontroller” on page 190.
If the Flash memory size on the device is less than 192 KB, this register usually reads as zeroes,
but software should not rely on these bits to be zero. For additional information, see “Flash Memory
Protection” on page 305.
Flash Memory Protection Program Enable 3 (FMPPE3)
Base 0x400F.E000
Offset 0x40C
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
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
PROG_ENABLE
Type
Reset
PROG_ENABLE
Type
Reset
Bit/Field
Name
Type
31:0
PROG_ENABLE
R/W
Reset
R/W
0
R/W
0
Description
0x00000000 Flash Programming Enable
Configures 2-KB flash blocks to be execute only. The policies may be
combined as shown in Table 6-1 on page 305.
Value
Description
0x00000000 Bits [31:0] each enable protection on a 2-KB block of
Flash memory in the range from 193 to 256 KB.
July 03, 2014
337
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
7
Micro Direct Memory Access (μDMA)
The LM3S5791 microcontroller includes a Direct Memory Access (DMA) controller, known as
micro-DMA (μDMA). The μDMA controller provides a way to offload data transfer tasks from the
Cortex™-M3 processor, allowing for more efficient use of the processor and the available bus
bandwidth. The μDMA controller can perform transfers between memory and peripherals. It has
dedicated channels for each supported on-chip module and can be programmed to automatically
perform transfers between peripherals and memory as the peripheral is ready to transfer more data.
The μDMA controller provides the following features:
®
®
■ ARM PrimeCell 32-channel configurable µDMA controller
■ Support for memory-to-memory, memory-to-peripheral, and peripheral-to-memory in multiple
transfer modes
– Basic for simple transfer scenarios
– Ping-pong for continuous data flow
– Scatter-gather for a programmable list of up to 256 arbitrary transfers initiated from a single
request
■ Highly flexible and configurable channel operation
– Independently configured and operated channels
– Dedicated channels for supported on-chip modules
– Primary and secondary channel assignments
– One channel each for receive and transmit path for bidirectional modules
– Dedicated channel for software-initiated transfers
– Per-channel configurable priority scheme
– Optional software-initiated requests for any channel
■ Two levels of priority
■ Design optimizations for improved bus access performance between µDMA controller and the
processor core
– µDMA controller access is subordinate to core access
– RAM striping
– Peripheral bus segmentation
■ Data sizes of 8, 16, and 32 bits
■ Transfer size is programmable in binary steps from 1 to 1024
■ Source and destination address increment size of byte, half-word, word, or no increment
338
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■ Maskable peripheral requests
7.1
Block Diagram
Figure 7-1. μDMA Block Diagram
uDMA
Controller
DMA error
System Memory
CH Control Table
Peripheral
DMA Channel 0
•
•
•
Peripheral
DMA Channel N-1
Nested
Vectored
Interrupt
Controller
(NVIC)
IRQ
General
Peripheral N
Registers
request
done
request
done
request
done
DMASTAT
DMACFG
DMACTLBASE
DMAALTBASE
DMAWAITSTAT
DMASWREQ
DMAUSEBURSTSET
DMAUSEBURSTCLR
DMAREQMASKSET
DMAREQMASKCLR
DMAENASET
DMAENACLR
DMAALTSET
DMAALTCLR
DMAPRIOSET
DMAPRIOCLR
DMAERRCLR
DMACHASGN
DMASRCENDP
DMADSTENDP
DMACHCTRL
•
•
•
DMASRCENDP
DMADSTENDP
DMACHCTRL
Transfer Buffers
Used by µDMA
ARM
Cortex-M3
7.2
Functional Description
The μDMA controller is a flexible and highly configurable DMA controller designed to work efficiently
with the microcontroller's Cortex-M3 processor core. It supports multiple data sizes and address
increment schemes, multiple levels of priority among DMA channels, and several transfer modes
to allow for sophisticated programmed data transfers. The μDMA controller's usage of the bus is
always subordinate to the processor core, so it never holds up a bus transaction by the processor.
Because the μDMA controller is only using otherwise-idle bus cycles, the data transfer bandwidth
it provides is essentially free, with no impact on the rest of the system. The bus architecture has
been optimized to greatly enhance the ability of the processor core and the μDMA controller to
efficiently share the on-chip bus, thus improving performance. The optimizations include RAM
striping and peripheral bus segmentation, which in many cases allow both the processor core and
the μDMA controller to access the bus and perform simultaneous data transfers.
The μDMA controller can transfer data to and from the on-chip SRAM. However, because the Flash
memory and ROM are located on a separate internal bus, it is not possible to transfer data from the
Flash memory or ROM with the μDMA controller.
Each peripheral function that is supported has a dedicated channel on the μDMA controller that can
be configured independently. The μDMA controller implements a unique configuration method using
channel control structures that are maintained in system memory by the processor. While simple
transfer modes are supported, it is also possible to build up sophisticated "task" lists in memory that
allow the μDMA controller to perform arbitrary-sized transfers to and from arbitrary locations as part
of a single transfer request. The μDMA controller also supports the use of ping-pong buffering to
accommodate constant streaming of data to or from a peripheral.
July 03, 2014
339
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Each channel also has a configurable arbitration size. The arbitration size is the number of items
that are transferred in a burst before the μDMA controller rearbitrates for channel priority. Using the
arbitration size, it is possible to control exactly how many items are transferred to or from a peripheral
each time it makes a μDMA service request.
7.2.1
Channel Assignments
μDMA channels 0-31 are assigned to peripherals according to the following table. The DMA Channel
Assignment (DMACHASGN) register (see page 387) can be used to specify the primary or secondary
assignment. If the primary function is not available on this microcontroller, the secondary function
becomes the primary function. If the secondary function is not available, the primary function is the
only option.
Note:
Channels noted in the table as "Available for software" may be assigned to peripherals in
the future. However, they are currently available for software use. Channel 30 is dedicated
for software use.
The USB endpoints mapped to μDMA channels 0-3 can be changed with the USBDMASEL
register (see page 1047).
Because of the way the μDMA controller interacts with peripherals, the μDMA channel for
the peripheral must be enabled in order for the μDMA controller to be able to read and write
the peripheral registers, even if a different μDMA channel is used to perform the μDMA
transfer. To minimize confusion and chance of software errors, it is best practice to use a
peripheral's μDMA channel for performing all μDMA transfers for that peripheral, even if it
is processor-triggered and using AUTO mode, which could be considered a software transfer.
Note that if the software channel is used, interrupts occur on the dedicated μDMA interrupt
vector. If the peripheral channel is used, then the interrupt occurs on the interrupt vector
for the peripheral.
Table 7-1. μDMA Channel Assignments
μDMA Channel
Primary Assignment
Secondary Assignment
0
USB Endpoint 1 Receive
UART2 Receive
1
USB Endpoint 1 Transmit
UART2 Transmit
2
USB Endpoint 2 Receive
General-Purpose Timer 3A
3
USB Endpoint 2 Transmit
General-Purpose Timer 3B
4
USB Endpoint 3 Receive
General-Purpose Timer 2A
5
USB Endpoint 3 Transmit
General-Purpose Timer 2B
6
Available for software
General-Purpose Timer 2A
7
Available for software
General-Purpose Timer 2B
8
UART0 Receive
UART1 Receive
9
UART0 Transmit
UART1 Transmit
10
SSI0 Receive
SSI1 Receive
11
SSI0 Transmit
SSI1 Transmit
12
Available for software
UART2 Receive
13
Available for software
UART2 Transmit
14
ADC0 Sample Sequencer 0
General-Purpose Timer 2A
15
ADC0 Sample Sequencer 1
General-Purpose Timer 2B
16
ADC0 Sample Sequencer 2
Available for software
17
ADC0 Sample Sequencer 3
Available for software
340
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 7-1. μDMA Channel Assignments (continued)
μDMA Channel
7.2.2
Primary Assignment
Secondary Assignment
18
General-Purpose Timer 0A
General-Purpose Timer 1A
19
General-Purpose Timer 0B
General-Purpose Timer 1B
20
General-Purpose Timer 1A
EPI0 NBRFIFO
21
General-Purpose Timer 1B
EPI0 WFIFO
22
UART1 Receive
Available for software
23
UART1 Transmit
Available for software
24
SSI1 Receive
ADC1 Sample Sequencer 0
25
SSI1 Transmit
ADC1 Sample Sequencer 1
26
Available for software
ADC1 Sample Sequencer 2
27
Available for software
ADC1 Sample Sequencer 3
28
I2S0 Receive
Available for software
29
I2S0
Available for software
30
Dedicated for software use
31
Reserved
Transmit
Priority
The μDMA controller assigns priority to each channel based on the channel number and the priority
level bit for the channel. Channel number 0 has the highest priority and as the channel number
increases, the priority of a channel decreases. Each channel has a priority level bit to provide two
levels of priority: default priority and high priority. If the priority level bit is set, then that channel has
higher priority than all other channels at default priority. If multiple channels are set for high priority,
then the channel number is used to determine relative priority among all the high priority channels.
The priority bit for a channel can be set using the DMA Channel Priority Set (DMAPRIOSET)
register and cleared with the DMA Channel Priority Clear (DMAPRIOCLR) register.
7.2.3
Arbitration Size
When a μDMA channel requests a transfer, the μDMA controller arbitrates among all the channels
making a request and services the μDMA channel with the highest priority. Once a transfer begins,
it continues for a selectable number of transfers before rearbitrating among the requesting channels
again. The arbitration size can be configured for each channel, ranging from 1 to 1024 item transfers.
After the μDMA controller transfers the number of items specified by the arbitration size, it then
checks among all the channels making a request and services the channel with the highest priority.
If a lower priority μDMA channel uses a large arbitration size, the latency for higher priority channels
is increased because the μDMA controller completes the lower priority burst before checking for
higher priority requests. Therefore, lower priority channels should not use a large arbitration size
for best response on high priority channels.
The arbitration size can also be thought of as a burst size. It is the maximum number of items that
are transferred at any one time in a burst. Here, the term arbitration refers to determination of μDMA
channel priority, not arbitration for the bus. When the μDMA controller arbitrates for the bus, the
processor always takes priority. Furthermore, the μDMA controller is held off whenever the processor
must perform a bus transaction on the same bus, even in the middle of a burst transfer.
July 03, 2014
341
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
7.2.4
Request Types
The μDMA controller responds to two types of requests from a peripheral: single or burst. Each
peripheral may support either or both types of requests. A single request means that the peripheral
is ready to transfer one item, while a burst request means that the peripheral is ready to transfer
multiple items.
The μDMA controller responds differently depending on whether the peripheral is making a single
request or a burst request. If both are asserted, and the μDMA channel has been set up for a burst
transfer, then the burst request takes precedence. See Table 7-2 on page 342, which shows how
each peripheral supports the two request types.
Table 7-2. Request Type Support
7.2.4.1
Peripheral
Single Request Signal
Burst Request Signal
ADC
None
Sequencer IE bit
EPI WFIFO
None
WFIFO Level (configurable)
EPI NBRFIFO
None
NBRFIFO Level (configurable)
General-Purpose Timer
None
Trigger event
I2S TX
None
FIFO service request
I2S
None
FIFO service request
SSI TX
TX FIFO Not Full
TX FIFO Level (fixed at 4)
SSI RX
RX FIFO Not Empty
RX FIFO Level (fixed at 4)
UART TX
TX FIFO Not Full
TX FIFO Level (configurable)
UART RX
RX FIFO Not Empty
RX FIFO Level (configurable)
USB TX
None
FIFO TXRDY
USB RX
None
FIFO RXRDY
RX
Single Request
When a single request is detected, and not a burst request, the μDMA controller transfers one item
and then stops to wait for another request.
7.2.4.2
Burst Request
When a burst request is detected, the μDMA controller transfers the number of items that is the
lesser of the arbitration size or the number of items remaining in the transfer. Therefore, the arbitration
size should be the same as the number of data items that the peripheral can accommodate when
making a burst request. For example, the UART generates a burst request based on the FIFO trigger
level. In this case, the arbitration size should be set to the amount of data that the FIFO can transfer
when the trigger level is reached. A burst transfer runs to completion once it is started, and cannot
be interrupted, even by a higher priority channel. Burst transfers complete in a shorter time than the
same number of non-burst transfers.
It may be desirable to use only burst transfers and not allow single transfers. For example, perhaps
the nature of the data is such that it only makes sense when transferred together as a single unit
rather than one piece at a time. The single request can be disabled by using the DMA Channel
Useburst Set (DMAUSEBURSTSET) register. By setting the bit for a channel in this register, the
μDMA controller only responds to burst requests for that channel.
342
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
7.2.5
Channel Configuration
The μDMA controller uses an area of system memory to store a set of channel control structures
in a table. The control table may have one or two entries for each μDMA channel. Each entry in the
table structure contains source and destination pointers, transfer size, and transfer mode. The
control table can be located anywhere in system memory, but it must be contiguous and aligned on
a 1024-byte boundary.
Table 7-3 on page 343 shows the layout in memory of the channel control table. Each channel may
have one or two control structures in the control table: a primary control structure and an optional
alternate control structure. The table is organized so that all of the primary entries are in the first
half of the table, and all the alternate structures are in the second half of the table. The primary entry
is used for simple transfer modes where transfers can be reconfigured and restarted after each
transfer is complete. In this case, the alternate control structures are not used and therefore only
the first half of the table must be allocated in memory; the second half of the control table is not
necessary, and that memory can be used for something else. If a more complex transfer mode is
used such as ping-pong or scatter-gather, then the alternate control structure is also used and
memory space should be allocated for the entire table.
Any unused memory in the control table may be used by the application. This includes the control
structures for any channels that are unused by the application as well as the unused control word
for each channel.
Table 7-3. Control Structure Memory Map
Offset
Channel
0x0
0, Primary
0x10
1, Primary
...
...
0x1F0
31, Primary
0x200
0, Alternate
0x210
1, Alternate
...
0x3F0
...
31, Alternate
Table 7-4 shows an individual control structure entry in the control table. Each entry is aligned on
a 16-byte boundary. The entry contains four long words: the source end pointer, the destination end
pointer, the control word, and an unused entry. The end pointers point to the ending address of the
transfer and are inclusive. If the source or destination is non-incrementing (as for a peripheral
register), then the pointer should point to the transfer address.
Table 7-4. Channel Control Structure
Offset
Description
0x000
Source End Pointer
0x004
Destination End Pointer
0x008
Control Word
0x00C
Unused
The control word contains the following fields:
■ Source and destination data sizes
July 03, 2014
343
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
■ Source and destination address increment size
■ Number of transfers before bus arbitration
■ Total number of items to transfer
■ Useburst flag
■ Transfer mode
The control word and each field are described in detail in “μDMA Channel Control
Structure” on page 361. The μDMA controller updates the transfer size and transfer mode fields as
the transfer is performed. At the end of a transfer, the transfer size indicates 0, and the transfer
mode indicates "stopped." Because the control word is modified by the μDMA controller, it must be
reconfigured before each new transfer. The source and destination end pointers are not modified,
so they can be left unchanged if the source or destination addresses remain the same.
Prior to starting a transfer, a μDMA channel must be enabled by setting the appropriate bit in the
DMA Channel Enable Set (DMAENASET) register. A channel can be disabled by setting the
channel bit in the DMA Channel Enable Clear (DMAENACLR) register. At the end of a complete
μDMA transfer, the controller automatically disables the channel.
7.2.6
Transfer Modes
The μDMA controller supports several transfer modes. Two of the modes support simple one-time
transfers. Several complex modes support a continuous flow of data.
7.2.6.1
Stop Mode
While Stop is not actually a transfer mode, it is a valid value for the mode field of the control word.
When the mode field has this value, the μDMA controller does not perform any transfers and disables
the channel if it is enabled. At the end of a transfer, the μDMA controller updates the control word
to set the mode to Stop.
7.2.6.2
Basic Mode
In Basic mode, the μDMA controller performs transfers as long as there are more items to transfer,
and a transfer request is present. This mode is used with peripherals that assert a μDMA request
signal whenever the peripheral is ready for a data transfer. Basic mode should not be used in any
situation where the request is momentary even though the entire transfer should be completed. For
example, a software-initiated transfer creates a momentary request, and in Basic mode, only the
number of transfers specified by the ARBSIZE field in the DMA Channel Control Word (DMACHCTL)
register is transferred on a software request, even if there is more data to transfer.
When all of the items have been transferred using Basic mode, the μDMA controller sets the mode
for that channel to Stop.
7.2.6.3
Auto Mode
Auto mode is similar to Basic mode, except that once a transfer request is received, the transfer
runs to completion, even if the μDMA request is removed. This mode is suitable for software-triggered
transfers. Generally, Auto mode is not used with a peripheral.
When all the items have been transferred using Auto mode, the μDMA controller sets the mode for
that channel to Stop.
344
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
7.2.6.4
Ping-Pong
Ping-Pong mode is used to support a continuous data flow to or from a peripheral. To use Ping-Pong
mode, both the primary and alternate data structures must be implemented. Both structures are set
up by the processor for data transfer between memory and a peripheral. The transfer is started
using the primary control structure. When the transfer using the primary control structure is complete,
the μDMA controller reads the alternate control structure for that channel to continue the transfer.
Each time this happens, an interrupt is generated, and the processor can reload the control structure
for the just-completed transfer. Data flow can continue indefinitely this way, using the primary and
alternate control structures to switch back and forth between buffers as the data flows to or from
the peripheral.
Refer to Figure 7-2 on page 346 for an example showing operation in Ping-Pong mode.
July 03, 2014
345
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Figure 7-2. Example of Ping-Pong μDMA Transaction
µDMA Controller
SOURCE
DEST
CONTROL
Unused
transfers using BUFFER A
transfer continues using alternate
Primary Structure
Cortex-M3 Processor
SOURCE
DEST
CONTROL
Unused
Pe
rip
he
ral
/µD
M
AI
nte
rru
p
t
transfers using BUFFER B
Time
SOURCE
DEST
CONTROL
Unused
Pe
Alternate Structure
7.2.6.5
SOURCE
DEST
CONTROL
Unused
rip
he
ral
/µD
M
AI
nte
transfers using BUFFER A
rru
pt
BUFFER A
· Process data in BUFFER B
· Reload alternate structure
transfer continues using alternate
Primary Structure
BUFFER B
· Process data in BUFFER A
· Reload primary structure
transfer continues using primary
Alternate Structure
BUFFER A
Pe
rip
he
ral
/µD
M
AI
nte
transfers using BUFFER B
rru
pt
BUFFER B
· Process data in BUFFER B
· Reload alternate structure
Memory Scatter-Gather
Memory Scatter-Gather mode is a complex mode used when data must be transferred to or from
varied locations in memory instead of a set of contiguous locations in a memory buffer. For example,
a gather μDMA operation could be used to selectively read the payload of several stored packets
of a communication protocol and store them together in sequence in a memory buffer.
346
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
In Memory Scatter-Gather mode, the primary control structure is used to program the alternate
control structure from a table in memory. The table is set up by the processor software and contains
a list of control structures, each containing the source and destination end pointers, and the control
word for a specific transfer. The mode of each control word must be set to Scatter-Gather mode.
Each entry in the table is copied in turn to the alternate structure where it is then executed. The
μDMA controller alternates between using the primary control structure to copy the next transfer
instruction from the list and then executing the new transfer instruction. The end of the list is marked
by programming the control word for the last entry to use Auto transfer mode. Once the last transfer
is performed using Auto mode, the μDMA controller stops. A completion interrupt is generated only
after the last transfer. It is possible to loop the list by having the last entry copy the primary control
structure to point back to the beginning of the list (or to a new list). It is also possible to trigger a set
of other channels to perform a transfer, either directly, by programming a write to the software trigger
for another channel, or indirectly, by causing a peripheral action that results in a μDMA request.
By programming the μDMA controller using this method, a set of up to 256 arbitrary transfers can
be performed based on a single μDMA request.
Refer to Figure 7-3 on page 348 and Figure 7-4 on page 349, which show an example of operation
in Memory Scatter-Gather mode. This example shows a gather operation, where data in three
separate buffers in memory is copied together into one buffer. Figure 7-3 on page 348 shows how
the application sets up a μDMA task list in memory that is used by the controller to perform three
sets of copy operations from different locations in memory. The primary control structure for the
channel that is used for the operation is configured to copy from the task list to the alternate control
structure.
Figure 7-4 on page 349 shows the sequence as the μDMA controller performs the three sets of copy
operations. First, using the primary control structure, the μDMA controller loads the alternate control
structure with task A. It then performs the copy operation specified by task A, copying the data from
the source buffer A to the destination buffer. Next, the μDMA controller again uses the primary
control structure to load task B into the alternate control structure, and then performs the B operation
with the alternate control structure. The process is repeated for task C.
July 03, 2014
347
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Figure 7-3. Memory Scatter-Gather, Setup and Configuration
1
2
3
Source and Destination
Buffer in Memory
Task List in Memory
Channel Control
Table in Memory
4 WORDS (SRC A)
SRC
A
DST
ITEMS=4
16 WORDS (SRC B)
SRC
Unused
DST
SRC
ITEMS=12
DST
B
“TASK” A
ITEMS=16
Channel Primary
Control Structure
“TASK” B
Unused
SRC
DST
ITEMS=1
“TASK” C
Unused
SRC
DST
Channel Alternate
Control Structure
ITEMS=n
1 WORD (SRC C)
C
4 (DEST A)
16 (DEST B)
1 (DEST C)
NOTES:
1. Application has a need to copy data items from three separate locations in memory into one combined buffer.
2. Application sets up µDMA “task list” in memory, which contains the pointers and control configuration for three
µDMA copy “tasks.”
3. Application sets up the channel primary control structure to copy each task configuration, one at a time, to the
alternate control structure, where it is executed by the µDMA controller.
4. The SRC and DST pointers in the task list must point to the last location in the corresponding buffer.
348
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 7-4. Memory Scatter-Gather, μDMA Copy Sequence
Task List
in Memory
Buffers
in Memory
µDMA Control Table
in Memory
SRC A
SRC
SRC B
PRI
COPIED
DST
TASK A
TASK B
SRC
SRC C
ALT
COPIED
DST
TASK C
DEST A
DEST B
DEST C
Then, using the channel’s alternate control structure, the
µDMA controller copies data from the source buffer A to
the destination buffer.
Using the channel’s primary control structure, the µDMA
controller copies task A configuration to the channel’s
alternate control structure.
Task List
in Memory
Buffers
in Memory
µDMA Control Table
in Memory
SRC A
SRC B
SRC
PRI
DST
TASK A
SRC
TASK B
TASK C
SRC C
COPIED
ALT
COPIED
DST
DEST A
DEST B
DEST C
Then, using the channel’s alternate control structure, the
µDMA controller copies data from the source buffer B to
the destination buffer.
Using the channel’s primary control structure, the µDMA
controller copies task B configuration to the channel’s
alternate control structure.
Task List
in Memory
Buffers
in Memory
µDMA Control Table
in Memory
SRC A
SRC
SRC B
PRI
DST
TASK A
SRC
TASK B
TASK C
SRC C
ALT
DST
DEST A
COPIED
COPIED
DEST B
DEST C
Using the channel’s primary control structure, the µDMA
controller copies task C configuration to the channel’s
alternate control structure.
Then, using the channel’s alternate control structure, the
µDMA controller copies data from the source buffer C to
the destination buffer.
July 03, 2014
349
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
7.2.6.6
Peripheral Scatter-Gather
Peripheral Scatter-Gather mode is very similar to Memory Scatter-Gather, except that the transfers
are controlled by a peripheral making a μDMA request. Upon detecting a request from the peripheral,
the μDMA controller uses the primary control structure to copy one entry from the list to the alternate
control structure and then performs the transfer. At the end of this transfer, the next transfer is started
only if the peripheral again asserts a μDMA request. The μDMA controller continues to perform
transfers from the list only when the peripheral is making a request, until the last transfer is complete.
A completion interrupt is generated only after the last transfer.
By using this method, the μDMA controller can transfer data to or from a peripheral from a set of
arbitrary locations whenever the peripheral is ready to transfer data.
Refer to Figure 7-5 on page 351 and Figure 7-6 on page 352, which show an example of operation
in Peripheral Scatter-Gather mode. This example shows a gather operation, where data from three
separate buffers in memory is copied to a single peripheral data register. Figure 7-5 on page 351
shows how the application sets up a µDMA task list in memory that is used by the controller to
perform three sets of copy operations from different locations in memory. The primary control
structure for the channel that is used for the operation is configured to copy from the task list to the
alternate control structure.
Figure 7-6 on page 352 shows the sequence as the µDMA controller performs the three sets of copy
operations. First, using the primary control structure, the µDMA controller loads the alternate control
structure with task A. It then performs the copy operation specified by task A, copying the data from
the source buffer A to the peripheral data register. Next, the µDMA controller again uses the primary
control structure to load task B into the alternate control structure, and then performs the B operation
with the alternate control structure. The process is repeated for task C.
350
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 7-5. Peripheral Scatter-Gather, Setup and Configuration
1
2
3
Source Buffer
in Memory
Task List in Memory
Channel Control
Table in Memory
4 WORDS (SRC A)
SRC
A
DST
ITEMS=4
16 WORDS (SRC B)
SRC
DST
SRC
ITEMS=12
DST
B
“TASK” A
Unused
ITEMS=16
Channel Primary
Control Structure
“TASK” B
Unused
SRC
DST
ITEMS=1
“TASK” C
Unused
SRC
DST
Channel Alternate
Control Structure
ITEMS=n
1 WORD (SRC C)
C
Peripheral Data
Register
DEST
NOTES:
1. Application has a need to copy data items from three separate locations in memory into a peripheral data
register.
2. Application sets up µDMA “task list” in memory, which contains the pointers and control configuration for three
µDMA copy “tasks.”
3. Application sets up the channel primary control structure to copy each task configuration, one at a time, to the
alternate control structure, where it is executed by the µDMA controller.
July 03, 2014
351
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Figure 7-6. Peripheral Scatter-Gather, μDMA Copy Sequence
Task List
in Memory
Buffers
in Memory
µDMA Control Table
in Memory
SRC A
SRC
SRC B
PRI
COPIED
DST
TASK A
TASK B
SRC
SRC C
ALT
COPIED
DST
TASK C
Then, using the channel’s alternate control structure, the
µDMA controller copies data from the source buffer A to
the peripheral data register.
Using the channel’s primary control structure, the µDMA
controller copies task A configuration to the channel’s
alternate control structure.
Task List
in Memory
Peripheral
Data
Register
Buffers
in Memory
µDMA Control Table
in Memory
SRC A
SRC
SRC B
PRI
DST
TASK A
SRC
TASK B
TASK C
SRC C
COPIED
ALT
COPIED
DST
Then, using the channel’s alternate control structure, the
µDMA controller copies data from the source buffer B to
the peripheral data register.
Using the channel’s primary control structure, the µDMA
controller copies task B configuration to the channel’s
alternate control structure.
Task List
in Memory
Peripheral
Data
Register
Buffers
in Memory
µDMA Control Table
in Memory
SRC A
SRC
SRC B
PRI
DST
TASK A
SRC
TASK B
TASK C
SRC C
ALT
DST
COPIED
COPIED
Peripheral
Data
Register
Using the channel’s primary control structure, the µDMA
controller copies task C configuration to the channel’s
alternate control structure.
Then, using the channel’s alternate control structure, the
µDMA controller copies data from the source buffer C to
the peripheral data register.
352
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
7.2.7
Transfer Size and Increment
The μDMA controller supports transfer data sizes of 8, 16, or 32 bits. The source and destination
data size must be the same for any given transfer. The source and destination address can be
auto-incremented by bytes, half-words, or words, or can be set to no increment. The source and
destination address increment values can be set independently, and it is not necessary for the
address increment to match the data size as long as the increment is the same or larger than the
data size. For example, it is possible to perform a transfer using 8-bit data size, but using an address
increment of full words (4 bytes). The data to be transferred must be aligned in memory according
to the data size (8, 16, or 32 bits).
Table 7-5 shows the configuration to read from a peripheral that supplies 8-bit data.
Table 7-5. μDMA Read Example: 8-Bit Peripheral
7.2.8
Field
Configuration
Source data size
8 bits
Destination data size
8 bits
Source address increment
No increment
Destination address increment
Byte
Source end pointer
Peripheral read FIFO register
Destination end pointer
End of the data buffer in memory
Peripheral Interface
Each peripheral that supports μDMA has a single request and/or burst request signal that is asserted
when the peripheral is ready to transfer data (see Table 7-2 on page 342). The request signal can
be disabled or enabled using the DMA Channel Request Mask Set (DMAREQMASKSET) and
DMA Channel Request Mask Clear (DMAREQMASKCLR) registers. The μDMA request signal
is disabled, or masked, when the channel request mask bit is set. When the request is not masked,
the μDMA channel is configured correctly and enabled, and the peripheral asserts the request signal,
the μDMA controller begins the transfer.
Note:
When using μDMA to transfer data to and from a peripheral, the peripheral must disable all
interrupts to the NVIC.
When a μDMA transfer is complete, the μDMA controller generates an interrupt, see “Interrupts and
Errors” on page 354 for more information.
For more information on how a specific peripheral interacts with the μDMA controller, refer to the
DMA Operation section in the chapter that discusses that peripheral.
7.2.9
Software Request
One μDMA channel is dedicated to software-initiated transfers. This channel also has a dedicated
interrupt to signal completion of a μDMA transfer. A transfer is initiated by software by first configuring
and enabling the transfer, and then issuing a software request using the DMA Channel Software
Request (DMASWREQ) register. For software-based transfers, the Auto transfer mode should be
used.
It is possible to initiate a transfer on any channel using the DMASWREQ register. If a request is
initiated by software using a peripheral μDMA channel, then the completion interrupt occurs on the
interrupt vector for the peripheral instead of the software interrupt vector. Any channel may be used
for software requests as long as the corresponding peripheral is not using μDMA for data transfer.
July 03, 2014
353
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
7.2.10
Interrupts and Errors
When a μDMA transfer is complete, the μDMA controller generates a completion interrupt on the
interrupt vector of the peripheral. Therefore, if μDMA is used to transfer data for a peripheral and
interrupts are used, then the interrupt handler for that peripheral must be designed to handle the
μDMA transfer completion interrupt. If the transfer uses the software μDMA channel, then the
completion interrupt occurs on the dedicated software μDMA interrupt vector (see Table
7-6 on page 354).
When μDMA is enabled for a peripheral, the μDMA controller stops the normal transfer interrupts
for a peripheral from reaching the interrupt controller (the interrupts are still reported in the peripheral's
interrupt registers). Thus, when a large amount of data is transferred using μDMA, instead of receiving
multiple interrupts from the peripheral as data flows, the interrupt controller receives only one interrupt
when the transfer is complete. Unmasked peripheral error interrupts continue to be sent to the
interrupt controller.
If the μDMA controller encounters a bus or memory protection error as it attempts to perform a data
transfer, it disables the μDMA channel that caused the error and generates an interrupt on the μDMA
error interrupt vector. The processor can read the DMA Bus Error Clear (DMAERRCLR) register
to determine if an error is pending. The ERRCLR bit is set if an error occurred. The error can be
cleared by writing a 1 to the ERRCLR bit.
Table 7-6 shows the dedicated interrupt assignments for the μDMA controller.
Table 7-6. μDMA Interrupt Assignments
Interrupt
Assignment
46
μDMA Software Channel Transfer
47
μDMA Error
7.3
Initialization and Configuration
7.3.1
Module Initialization
Before the μDMA controller can be used, it must be enabled in the System Control block and in the
peripheral. The location of the channel control structure must also be programmed.
The following steps should be performed one time during system initialization:
1. The μDMA peripheral must be enabled in the System Control block. To do this, set the UDMA
bit of the System Control RCGC2 register (see page 288).
2. Enable the μDMA controller by setting the MASTEREN bit of the DMA Configuration (DMACFG)
register.
3. Program the location of the channel control table by writing the base address of the table to the
DMA Channel Control Base Pointer (DMACTLBASE) register. The base address must be
aligned on a 1024-byte boundary.
7.3.2
Configuring a Memory-to-Memory Transfer
μDMA channel 30 is dedicated for software-initiated transfers. However, any channel can be used
for software-initiated, memory-to-memory transfer if the associated peripheral is not being used.
354
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
7.3.2.1
Configure the Channel Attributes
First, configure the channel attributes:
1. Program bit 30 of the DMA Channel Priority Set (DMAPRIOSET) or DMA Channel Priority
Clear (DMAPRIOCLR) registers to set the channel to High priority or Default priority.
2. Set bit 30 of the DMA Channel Primary Alternate Clear (DMAALTCLR) register to select the
primary channel control structure for this transfer.
3. Set bit 30 of the DMA Channel Useburst Clear (DMAUSEBURSTCLR) register to allow the
μDMA controller to respond to single and burst requests.
4. Set bit 30 of the DMA Channel Request Mask Clear (DMAREQMASKCLR) register to allow
the μDMA controller to recognize requests for this channel.
7.3.2.2
Configure the Channel Control Structure
Now the channel control structure must be configured.
This example transfers 256 words from one memory buffer to another. Channel 30 is used for a
software transfer, and the control structure for channel 30 is at offset 0x1E0 of the channel control
table. The channel control structure for channel 30 is located at the offsets shown in Table 7-7.
Table 7-7. Channel Control Structure Offsets for Channel 30
Offset
Description
Control Table Base + 0x1E0
Channel 30 Source End Pointer
Control Table Base + 0x1E4
Channel 30 Destination End Pointer
Control Table Base + 0x1E8
Channel 30 Control Word
Configure the Source and Destination
The source and destination end pointers must be set to the last address for the transfer (inclusive).
1. Program the source end pointer at offset 0x1E0 to the address of the source buffer + 0x3FC.
2. Program the destination end pointer at offset 0x1E4 to the address of the destination buffer +
0x3FC.
The control word at offset 0x1E8 must be programmed according to Table 7-8.
Table 7-8. Channel Control Word Configuration for Memory Transfer Example
Field in DMACHCTL
Bits
Value
DSTINC
31:30
2
32-bit destination address increment
DSTSIZE
29:28
2
32-bit destination data size
SRCINC
27:26
2
32-bit source address increment
SRCSIZE
25:24
2
32-bit source data size
reserved
23:18
0
Reserved
ARBSIZE
17:14
3
Arbitrates after 8 transfers
XFERSIZE
13:4
255
3
0
N/A for this transfer type
2:0
2
Use Auto-request transfer mode
NXTUSEBURST
XFERMODE
July 03, 2014
Description
Transfer 256 items
355
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
7.3.2.3
Start the Transfer
Now the channel is configured and is ready to start.
1. Enable the channel by setting bit 30 of the DMA Channel Enable Set (DMAENASET) register.
2. Issue a transfer request by setting bit 30 of the DMA Channel Software Request (DMASWREQ)
register.
The μDMA transfer begins. If the interrupt is enabled, then the processor is notified by interrupt
when the transfer is complete. If needed, the status can be checked by reading bit 30 of the
DMAENASET register. This bit is automatically cleared when the transfer is complete. The status
can also be checked by reading the XFERMODE field of the channel control word at offset 0x1E8.
This field is automatically cleared at the end of the transfer.
7.3.3
Configuring a Peripheral for Simple Transmit
This example configures the μDMA controller to transmit a buffer of data to a peripheral. The
peripheral has a transmit FIFO with a trigger level of 4. The example peripheral uses μDMA channel
7.
7.3.3.1
Configure the Channel Attributes
First, configure the channel attributes:
1. Configure bit 7 of the DMA Channel Priority Set (DMAPRIOSET) or DMA Channel Priority
Clear (DMAPRIOCLR) registers to set the channel to High priority or Default priority.
2. Set bit 7 of the DMA Channel Primary Alternate Clear (DMAALTCLR) register to select the
primary channel control structure for this transfer.
3. Set bit 7 of the DMA Channel Useburst Clear (DMAUSEBURSTCLR) register to allow the
μDMA controller to respond to single and burst requests.
4. Set bit 7 of the DMA Channel Request Mask Clear (DMAREQMASKCLR) register to allow
the μDMA controller to recognize requests for this channel.
7.3.3.2
Configure the Channel Control Structure
This example transfers 64 bytes from a memory buffer to the peripheral's transmit FIFO register
using μDMA channel 7. The control structure for channel 7 is at offset 0x070 of the channel control
table. The channel control structure for channel 7 is located at the offsets shown in Table 7-9.
Table 7-9. Channel Control Structure Offsets for Channel 7
Offset
Description
Control Table Base + 0x070
Channel 7 Source End Pointer
Control Table Base + 0x074
Channel 7 Destination End Pointer
Control Table Base + 0x078
Channel 7 Control Word
Configure the Source and Destination
The source and destination end pointers must be set to the last address for the transfer (inclusive).
Because the peripheral pointer does not change, it simply points to the peripheral's data register.
1. Program the source end pointer at offset 0x070 to the address of the source buffer + 0x3F.
356
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
2. Program the destination end pointer at offset 0x074 to the address of the peripheral's transmit
FIFO register.
The control word at offset 0x078 must be programmed according to Table 7-10.
Table 7-10. Channel Control Word Configuration for Peripheral Transmit Example
Field in DMACHCTL
Bits
Value
DSTINC
31:30
3
Destination address does not increment
DSTSIZE
29:28
0
8-bit destination data size
SRCINC
27:26
0
8-bit source address increment
SRCSIZE
25:24
0
8-bit source data size
reserved
23:18
0
Reserved
ARBSIZE
17:14
2
Arbitrates after 4 transfers
XFERSIZE
13:4
63
Transfer 64 items
3
0
N/A for this transfer type
2:0
1
Use Basic transfer mode
NXTUSEBURST
XFERMODE
Note:
7.3.3.3
Description
In this example, it is not important if the peripheral makes a single request or a burst request.
Because the peripheral has a FIFO that triggers at a level of 4, the arbitration size is set to
4. If the peripheral does make a burst request, then 4 bytes are transferred, which is what
the FIFO can accommodate. If the peripheral makes a single request (if there is any space
in the FIFO), then one byte is transferred at a time. If it is important to the application that
transfers only be made in bursts, then the Channel Useburst SET[7] bit should be set in
the DMA Channel Useburst Set (DMAUSEBURSTSET) register.
Start the Transfer
Now the channel is configured and is ready to start.
1. Enable the channel by setting bit 7 of the DMA Channel Enable Set (DMAENASET) register.
The μDMA controller is now configured for transfer on channel 7. The controller makes transfers to
the peripheral whenever the peripheral asserts a μDMA request. The transfers continue until the
entire buffer of 64 bytes has been transferred. When that happens, the μDMA controller disables
the channel and sets the XFERMODE field of the channel control word to 0 (Stopped). The status of
the transfer can be checked by reading bit 7 of the DMA Channel Enable Set (DMAENASET)
register. This bit is automatically cleared when the transfer is complete. The status can also be
checked by reading the XFERMODE field of the channel control word at offset 0x078. This field is
automatically cleared at the end of the transfer.
If peripheral interrupts are enabled, then the peripheral interrupt handler receives an interrupt when
the entire transfer is complete.
7.3.4
Configuring a Peripheral for Ping-Pong Receive
This example configures the μDMA controller to continuously receive 8-bit data from a peripheral
into a pair of 64-byte buffers. The peripheral has a receive FIFO with a trigger level of 8. The example
peripheral uses μDMA channel 8.
7.3.4.1
Configure the Channel Attributes
First, configure the channel attributes:
July 03, 2014
357
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
1. Configure bit 8 of the DMA Channel Priority Set (DMAPRIOSET) or DMA Channel Priority
Clear (DMAPRIOCLR) registers to set the channel to High priority or Default priority.
2. Set bit 8 of the DMA Channel Primary Alternate Clear (DMAALTCLR) register to select the
primary channel control structure for this transfer.
3. Set bit 8 of the DMA Channel Useburst Clear (DMAUSEBURSTCLR) register to allow the
μDMA controller to respond to single and burst requests.
4. Set bit 8 of the DMA Channel Request Mask Clear (DMAREQMASKCLR) register to allow
the μDMA controller to recognize requests for this channel.
7.3.4.2
Configure the Channel Control Structure
This example transfers bytes from the peripheral's receive FIFO register into two memory buffers
of 64 bytes each. As data is received, when one buffer is full, the μDMA controller switches to use
the other.
To use Ping-Pong buffering, both primary and alternate channel control structures must be used.
The primary control structure for channel 8 is at offset 0x080 of the channel control table, and the
alternate channel control structure is at offset 0x280. The channel control structures for channel 8
are located at the offsets shown in Table 7-11.
Table 7-11. Primary and Alternate Channel Control Structure Offsets for Channel 8
Offset
Description
Control Table Base + 0x080
Channel 8 Primary Source End Pointer
Control Table Base + 0x084
Channel 8 Primary Destination End Pointer
Control Table Base + 0x088
Channel 8 Primary Control Word
Control Table Base + 0x280
Channel 8 Alternate Source End Pointer
Control Table Base + 0x284
Channel 8 Alternate Destination End Pointer
Control Table Base + 0x288
Channel 8 Alternate Control Word
Configure the Source and Destination
The source and destination end pointers must be set to the last address for the transfer (inclusive).
Because the peripheral pointer does not change, it simply points to the peripheral's data register.
Both the primary and alternate sets of pointers must be configured.
1. Program the primary source end pointer at offset 0x080 to the address of the peripheral's receive
buffer.
2. Program the primary destination end pointer at offset 0x084 to the address of ping-pong buffer
A + 0x3F.
3. Program the alternate source end pointer at offset 0x280 to the address of the peripheral's
receive buffer.
4. Program the alternate destination end pointer at offset 0x284 to the address of ping-pong buffer
B + 0x3F.
The primary control word at offset 0x088 and the alternate control word at offset 0x288 are initially
programmed the same way.
1. Program the primary channel control word at offset 0x088 according to Table 7-12.
358
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
2. Program the alternate channel control word at offset 0x288 according to Table 7-12.
Table 7-12. Channel Control Word Configuration for Peripheral Ping-Pong Receive Example
Field in DMACHCTL
Bits
Value
DSTINC
31:30
0
8-bit destination address increment
DSTSIZE
29:28
0
8-bit destination data size
SRCINC
27:26
3
Source address does not increment
SRCSIZE
25:24
0
8-bit source data size
reserved
23:18
0
Reserved
ARBSIZE
17:14
3
Arbitrates after 8 transfers
XFERSIZE
13:4
63
Transfer 64 items
3
0
N/A for this transfer type
2:0
3
Use Ping-Pong transfer mode
NXTUSEBURST
XFERMODE
Note:
7.3.4.3
Description
In this example, it is not important if the peripheral makes a single request or a burst request.
Because the peripheral has a FIFO that triggers at a level of 8, the arbitration size is set to
8. If the peripheral does make a burst request, then 8 bytes are transferred, which is what
the FIFO can accommodate. If the peripheral makes a single request (if there is any data
in the FIFO), then one byte is transferred at a time. If it is important to the application that
transfers only be made in bursts, then the Channel Useburst SET[8] bit should be set in
the DMA Channel Useburst Set (DMAUSEBURSTSET) register.
Configure the Peripheral Interrupt
An interrupt handler should be configured when using μDMA Ping-Pong mode, it is best to use an
interrupt handler. However, the Ping-Pong mode can be configured without interrupts by polling.
The interrupt handler is triggered after each buffer is complete.
1. Configure and enable an interrupt handler for the peripheral.
7.3.4.4
Enable the μDMA Channel
Now the channel is configured and is ready to start.
1. Enable the channel by setting bit 8 of the DMA Channel Enable Set (DMAENASET) register.
7.3.4.5
Process Interrupts
The μDMA controller is now configured and enabled for transfer on channel 8. When the peripheral
asserts the μDMA request signal, the μDMA controller makes transfers into buffer A using the primary
channel control structure. When the primary transfer to buffer A is complete, it switches to the
alternate channel control structure and makes transfers into buffer B. At the same time, the primary
channel control word mode field is configured to indicate Stopped, and an interrupt is
When an interrupt is triggered, the interrupt handler must determine which buffer is complete and
process the data or set a flag that the data must be processed by non-interrupt buffer processing
code. Then the next buffer transfer must be set up.
In the interrupt handler:
1. Read the primary channel control word at offset 0x088 and check the XFERMODE field. If the
field is 0, this means buffer A is complete. If buffer A is complete, then:
July 03, 2014
359
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
a. Process the newly received data in buffer A or signal the buffer processing code that buffer
A has data available.
b. Reprogram the primary channel control word at offset 0x88 according to Table
7-12 on page 359.
2. Read the alternate channel control word at offset 0x288 and check the XFERMODE field. If the
field is 0, this means buffer B is complete. If buffer B is complete, then:
a. Process the newly received data in buffer B or signal the buffer processing code that buffer
B has data available.
b. Reprogram the alternate channel control word at offset 0x288 according to Table
7-12 on page 359.
7.3.5
Configuring Channel Assignments
Channel assignments for each μDMA channel can be changed using the DMACHASGN register.
Each bit represents a μDMA channel. If the bit is set, then the secondary function is used for the
channel.
Refer to Table 7-1 on page 340 for channel assignments.
For example, to use SSI1 Receive on channel 8 instead of UART0, set bit 8 of the DMACHASGN
register.
7.4
Register Map
Table 7-13 on page 360 lists the μDMA channel control structures and registers. The channel control
structure shows the layout of one entry in the channel control table. The channel control table is
located in system memory, and the location is determined by the application, that is, the base
address is n/a (not applicable). In the table below, the offset for the channel control structures is the
offset from the entry in the channel control table. See “Channel Configuration” on page 343 and Table
7-3 on page 343 for a description of how the entries in the channel control table are located in memory.
The μDMA register addresses are given as a hexadecimal increment, relative to the μDMA base
address of 0x400F.F000. Note that the μDMA module clock must be enabled before the registers
can be programmed (see page 288). There must be a delay of 3 system clocks after the μDMA
module clock is enabled before any μDMA module registers are accessed.
Table 7-13. μDMA Register Map
Offset
Name
Type
Reset
Description
See
page
μDMA Channel Control Structure (Offset from Channel Control Table Base)
0x000
DMASRCENDP
R/W
-
DMA Channel Source Address End Pointer
362
0x004
DMADSTENDP
R/W
-
DMA Channel Destination Address End Pointer
363
0x008
DMACHCTL
R/W
-
DMA Channel Control Word
364
DMA Status
369
DMA Configuration
371
DMA Channel Control Base Pointer
372
μDMA Registers (Offset from μDMA Base Address)
0x000
DMASTAT
RO
0x001F.0000
0x004
DMACFG
WO
-
0x008
DMACTLBASE
R/W
0x0000.0000
360
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 7-13. μDMA Register Map (continued)
Offset
Name
0x00C
Reset
DMAALTBASE
RO
0x0000.0200
DMA Alternate Channel Control Base Pointer
373
0x010
DMAWAITSTAT
RO
0xFFFF.FFC0
DMA Channel Wait-on-Request Status
374
0x014
DMASWREQ
WO
-
DMA Channel Software Request
375
0x018
DMAUSEBURSTSET
R/W
0x0000.0000
DMA Channel Useburst Set
376
0x01C
DMAUSEBURSTCLR
WO
-
DMA Channel Useburst Clear
377
0x020
DMAREQMASKSET
R/W
0x0000.0000
DMA Channel Request Mask Set
378
0x024
DMAREQMASKCLR
WO
-
DMA Channel Request Mask Clear
379
0x028
DMAENASET
R/W
0x0000.0000
DMA Channel Enable Set
380
0x02C
DMAENACLR
WO
-
DMA Channel Enable Clear
381
0x030
DMAALTSET
R/W
0x0000.0000
DMA Channel Primary Alternate Set
382
0x034
DMAALTCLR
WO
-
DMA Channel Primary Alternate Clear
383
0x038
DMAPRIOSET
R/W
0x0000.0000
DMA Channel Priority Set
384
0x03C
DMAPRIOCLR
WO
-
DMA Channel Priority Clear
385
0x04C
DMAERRCLR
R/W
0x0000.0000
DMA Bus Error Clear
386
0x500
DMACHASGN
R/W
0x0000.0000
DMA Channel Assignment
387
0xFD0
DMAPeriphID4
RO
0x0000.0004
DMA Peripheral Identification 4
392
0xFE0
DMAPeriphID0
RO
0x0000.0030
DMA Peripheral Identification 0
388
0xFE4
DMAPeriphID1
RO
0x0000.00B2
DMA Peripheral Identification 1
389
0xFE8
DMAPeriphID2
RO
0x0000.000B
DMA Peripheral Identification 2
390
0xFEC
DMAPeriphID3
RO
0x0000.0000
DMA Peripheral Identification 3
391
0xFF0
DMAPCellID0
RO
0x0000.000D
DMA PrimeCell Identification 0
393
0xFF4
DMAPCellID1
RO
0x0000.00F0
DMA PrimeCell Identification 1
394
0xFF8
DMAPCellID2
RO
0x0000.0005
DMA PrimeCell Identification 2
395
0xFFC
DMAPCellID3
RO
0x0000.00B1
DMA PrimeCell Identification 3
396
7.5
Description
See
page
Type
μDMA Channel Control Structure
The μDMA Channel Control Structure holds the transfer settings for a μDMA channel. Each channel
has two control structures, which are located in a table in system memory. Refer to “Channel
Configuration” on page 343 for an explanation of the Channel Control Table and the Channel Control
Structure.
The channel control structure is one entry in the channel control table. Each channel has a primary
and alternate structure. The primary control structures are located at offsets 0x0, 0x10, 0x20 and
so on. The alternate control structures are located at offsets 0x200, 0x210, 0x220, and so on.
July 03, 2014
361
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 1: DMA Channel Source Address End Pointer (DMASRCENDP), offset
0x000
DMA Channel Source Address End Pointer (DMASRCENDP) is part of the Channel Control
Structure and is used to specify the source address for a μDMA transfer.
The μDMA controller can transfer data to and from the on-chip SRAM. However, because the Flash
memory and ROM are located on a separate internal bus, it is not possible to transfer data from the
Flash memory or ROM with the μDMA controller.
Note:
The offset specified is from the base address of the control structure in system memory,
not the μDMA module base address.
DMA Channel Source Address End Pointer (DMASRCENDP)
Base n/a
Offset 0x000
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
7
6
5
4
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
ADDR
Type
Reset
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
ADDR
Type
Reset
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
Bit/Field
Name
Type
Reset
31:0
ADDR
R/W
-
R/W
-
Description
Source Address End Pointer
This field points to the last address of the μDMA transfer source
(inclusive). If the source address is not incrementing (the SRCINC field
in the DMACHCTL register is 0x3), then this field points at the source
location itself (such as a peripheral data register).
362
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 2: DMA Channel Destination Address End Pointer (DMADSTENDP),
offset 0x004
DMA Channel Destination Address End Pointer (DMADSTENDP) is part of the Channel Control
Structure and is used to specify the destination address for a μDMA transfer.
Note:
The offset specified is from the base address of the control structure in system memory,
not the μDMA module base address.
DMA Channel Destination Address End Pointer (DMADSTENDP)
Base n/a
Offset 0x004
Type R/W, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
ADDR
Type
Reset
ADDR
Type
Reset
Bit/Field
Name
Type
Reset
31:0
ADDR
R/W
-
Description
Destination Address End Pointer
This field points to the last address of the μDMA transfer destination
(inclusive). If the destination address is not incrementing (the DSTINC
field in the DMACHCTL register is 0x3), then this field points at the
destination location itself (such as a peripheral data register).
July 03, 2014
363
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 3: DMA Channel Control Word (DMACHCTL), offset 0x008
DMA Channel Control Word (DMACHCTL) is part of the Channel Control Structure and is used
to specify parameters of a μDMA transfer.
Note:
The offset specified is from the base address of the control structure in system memory,
not the μDMA module base address.
DMA Channel Control Word (DMACHCTL)
Base n/a
Offset 0x008
Type R/W, reset 31
30
DSTINC
28
27
DSTSIZE
26
24
23
22
21
SRCSIZE
20
19
18
17
reserved
16
ARBSIZE
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ARBSIZE
Type
Reset
25
SRCINC
R/W
-
R/W
-
NXTUSEBURST
Type
Reset
29
XFERSIZE
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
Bit/Field
Name
Type
Reset
31:30
DSTINC
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
XFERMODE
R/W
-
R/W
-
R/W
-
Description
Destination Address Increment
This field configures the destination address increment.
The address increment value must be equal or greater than the value
of the destination size (DSTSIZE).
Value Description
0x0
Byte
Increment by 8-bit locations
0x1
Half-word
Increment by 16-bit locations
0x2
Word
Increment by 32-bit locations
0x3
No increment
Address remains set to the value of the Destination Address
End Pointer (DMADSTENDP) for the channel
364
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
29:28
DSTSIZE
R/W
-
Description
Destination Data Size
This field configures the destination item data size.
Note:
DSTSIZE must be the same as SRCSIZE.
Value Description
0x0
Byte
8-bit data size
0x1
Half-word
16-bit data size
0x2
Word
32-bit data size
0x3
27:26
SRCINC
R/W
-
Reserved
Source Address Increment
This field configures the source address increment.
The address increment value must be equal or greater than the value
of the source size (SRCSIZE).
Value Description
0x0
Byte
Increment by 8-bit locations
0x1
Half-word
Increment by 16-bit locations
0x2
Word
Increment by 32-bit locations
0x3
No increment
Address remains set to the value of the Source Address End
Pointer (DMASRCENDP) for the channel
25:24
SRCSIZE
R/W
-
Source Data Size
This field configures the source item data size.
Note:
DSTSIZE must be the same as SRCSIZE.
Value Description
0x0
Byte
8-bit data size.
0x1
Half-word
16-bit data size.
0x2
Word
32-bit data size.
0x3
23:18
reserved
R/W
-
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.
July 03, 2014
365
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Bit/Field
Name
Type
Reset
17:14
ARBSIZE
R/W
-
Description
Arbitration Size
This field configures the number of transfers that can occur before the
μDMA controller re-arbitrates. The possible arbitration rate configurations
represent powers of 2 and are shown below.
Value
Description
0x0
1 Transfer
Arbitrates after each μDMA transfer
0x1
2 Transfers
0x2
4 Transfers
0x3
8 Transfers
0x4
16 Transfers
0x5
32 Transfers
0x6
64 Transfers
0x7
128 Transfers
0x8
256 Transfers
0x9
512 Transfers
0xA-0xF 1024 Transfers
In this configuration, no arbitration occurs during the μDMA
transfer because the maximum transfer size is 1024.
13:4
XFERSIZE
R/W
-
Transfer Size (minus 1)
This field configures the total number of items to transfer. The value of
this field is 1 less than the number to transfer (value 0 means transfer
1 item). The maximum value for this 10-bit field is 1023 which represents
a transfer size of 1024 items.
The transfer size is the number of items, not the number of bytes. If the
data size is 32 bits, then this value is the number of 32-bit words to
transfer.
The μDMA controller updates this field immediately prior to entering the
arbitration process, so it contains the number of outstanding items that
is necessary to complete the μDMA cycle.
3
NXTUSEBURST
R/W
-
Next Useburst
This field controls whether the Useburst SET[n] bit is automatically set
for the last transfer of a peripheral scatter-gather operation. Normally,
for the last transfer, if the number of remaining items to transfer is less
than the arbitration size, the μDMA controller uses single transfers to
complete the transaction. If this bit is set, then the controller uses a burst
transfer to complete the last transfer.
366
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
2:0
XFERMODE
R/W
-
Description
μDMA Transfer Mode
This field configures the operating mode of the μDMA cycle. Refer to
“Transfer Modes” on page 344 for a detailed explanation of transfer
modes.
Because this register is in system RAM, it has no reset value. Therefore,
this field should be initialized to 0 before the channel is enabled.
Value Description
0x0
Stop
0x1
Basic
0x2
Auto-Request
0x3
Ping-Pong
0x4
Memory Scatter-Gather
0x5
Alternate Memory Scatter-Gather
0x6
Peripheral Scatter-Gather
0x7
Alternate Peripheral Scatter-Gather
XFERMODE Bit Field Values.
Stop
Channel is stopped or configuration data is invalid. No more transfers can occur.
Basic
For each trigger (whether from a peripheral or a software request), the μDMA controller performs
the number of transfers specified by the ARBSIZE field.
Auto-Request
The initial request (software- or peripheral-initiated) is sufficient to complete the entire transfer
of XFERSIZE items without any further requests.
Ping-Pong
This mode uses both the primary and alternate control structures for this channel. When the
number of transfers specified by the XFERSIZE field have completed for the current control
structure (primary or alternate), the µDMA controller switches to the other one. These switches
continue until one of the control structures is not set to ping-pong mode. At that point, the µDMA
controller stops. An interrupt is generated on completion of the transfers configured by each
control structure. See “Ping-Pong” on page 345.
Memory Scatter-Gather
When using this mode, the primary control structure for the channel is configured to allow a list
of operations (tasks) to be performed. The source address pointer specifies the start of a table
of tasks to be copied to the alternate control structure for this channel. The XFERMODE field for
the alternate control structure should be configured to 0x5 (Alternate memory scatter-gather)
to perform the task. When the task completes, the µDMA switches back to the primary channel
control structure, which then copies the next task to the alternate control structure. This process
continues until the table of tasks is empty. The last task must have an XFERMODE value other
than 0x5. Note that for continuous operation, the last task can update the primary channel control
structure back to the start of the list or to another list. See “Memory Scatter-Gather” on page 346.
July 03, 2014
367
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Alternate Memory Scatter-Gather
This value must be used in the alternate channel control data structure when the μDMA controller
operates in Memory Scatter-Gather mode.
Peripheral Scatter-Gather
This value must be used in the primary channel control data structure when the μDMA controller
operates in Peripheral Scatter-Gather mode. In this mode, the μDMA controller operates exactly
the same as in Memory Scatter-Gather mode, except that instead of performing the number of
transfers specified by the XFERSIZE field in the alternate control structure at one time, the
μDMA controller only performs the number of transfers specified by the ARBSIZE field per
trigger; see Basic mode for details. See “Peripheral Scatter-Gather” on page 350.
Alternate Peripheral Scatter-Gather
This value must be used in the alternate channel control data structure when the μDMA controller
operates in Peripheral Scatter-Gather mode.
7.6
μDMA Register Descriptions
The register addresses given are relative to the μDMA base address of 0x400F.F000.
368
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 4: DMA Status (DMASTAT), offset 0x000
The DMA Status (DMASTAT) register returns the status of the μDMA controller. You cannot read
this register when the μDMA controller is in the reset state.
DMA Status (DMASTAT)
Base 0x400F.F000
Offset 0x000
Type RO, reset 0x001F.0000
31
30
29
28
27
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
RO
0
RO
0
RO
0
RO
0
26
25
24
23
22
21
20
19
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
1
RO
1
10
9
8
7
6
5
4
3
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
STATE
RO
0
17
16
RO
1
RO
1
RO
1
2
1
0
DMACHANS
reserved
Type
Reset
18
reserved
RO
0
MASTEN
RO
0
RO
0
Bit/Field
Name
Type
Reset
Description
31:21
reserved
RO
0x000
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
20:16
DMACHANS
RO
0x1F
Available μDMA Channels Minus 1
This field contains a value equal to the number of μDMA channels the
μDMA controller is configured to use, minus one. The value of 0x1F
corresponds to 32 μDMA channels.
15:8
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.
7:4
STATE
RO
0x0
Control State Machine Status
This field shows the current status of the control state machine. Status
can be one of the following.
Value
Description
0x0
Idle
0x1
Reading channel controller data.
0x2
Reading source end pointer.
0x3
Reading destination end pointer.
0x4
Reading source data.
0x5
Writing destination data.
0x6
Waiting for µDMA request to clear.
0x7
Writing channel controller data.
0x8
Stalled
0x9
Done
0xA-0xF Undefined
3:1
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.
July 03, 2014
369
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Bit/Field
Name
Type
Reset
0
MASTEN
RO
0
Description
Master Enable Status
Value Description
0
The μDMA controller is disabled.
1
The μDMA controller is enabled.
370
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 5: DMA Configuration (DMACFG), offset 0x004
The DMACFG register controls the configuration of the μDMA controller.
DMA Configuration (DMACFG)
Base 0x400F.F000
Offset 0x004
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
-
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
-
reserved
Type
Reset
reserved
Type
Reset
WO
-
MASTEN
WO
-
Bit/Field
Name
Type
Reset
Description
31:1
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.
0
MASTEN
WO
-
Controller Master Enable
Value Description
0
Disables the μDMA controller.
1
Enables μDMA controller.
July 03, 2014
371
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 6: DMA Channel Control Base Pointer (DMACTLBASE), offset 0x008
The DMACTLBASE register must be configured so that the base pointer points to a location in
system memory.
The amount of system memory that must be assigned to the μDMA controller depends on the
number of μDMA channels used and whether the alternate channel control data structure is used.
See “Channel Configuration” on page 343 for details about the Channel Control Table. The base
address must be aligned on a 1024-byte boundary. This register cannot be read when the μDMA
controller is in the reset state.
DMA Channel Control Base Pointer (DMACTLBASE)
Base 0x400F.F000
Offset 0x008
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
ADDR
Type
Reset
R/W
0
R/W
0
R/W
0
15
14
13
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
12
11
10
9
8
7
6
5
4
3
2
1
0
RO
0
RO
0
RO
0
RO
0
RO
0
ADDR
Type
Reset
R/W
0
R/W
0
R/W
0
reserved
R/W
0
R/W
0
R/W
0
RO
0
Bit/Field
Name
Type
Reset
31:10
ADDR
R/W
0x0000.00
RO
0
RO
0
RO
0
RO
0
Description
Channel Control Base Address
This field contains the pointer to the base address of the channel control
table. The base address must be 1024-byte aligned.
9:0
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.
372
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 7: DMA Alternate Channel Control Base Pointer (DMAALTBASE),
offset 0x00C
The DMAALTBASE register returns the base address of the alternate channel control data. This
register removes the necessity for application software to calculate the base address of the alternate
channel control structures. This register cannot be read when the μDMA controller is in the reset
state.
DMA Alternate Channel Control Base Pointer (DMAALTBASE)
Base 0x400F.F000
Offset 0x00C
Type RO, reset 0x0000.0200
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
ADDR
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
ADDR
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
31:0
ADDR
RO
RO
1
Reset
RO
0
Description
0x0000.0200 Alternate Channel Address Pointer
This field provides the base address of the alternate channel control
structures.
July 03, 2014
373
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 8: DMA Channel Wait-on-Request Status (DMAWAITSTAT), offset
0x010
This read-only register indicates that the μDMA channel is waiting on a request. A peripheral can
hold off the μDMA from performing a single request until the peripheral is ready for a burst request
to enhance the μDMA performance. The use of this feature is dependent on the design of the
peripheral and is not controllable by software in any way. This register cannot be read when the
μDMA controller is in the reset state.
DMA Channel Wait-on-Request Status (DMAWAITSTAT)
Base 0x400F.F000
Offset 0x010
Type RO, reset 0xFFFF.FFC0
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
WAITREQ[n]
Type
Reset
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
15
14
13
12
11
10
9
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
8
7
6
5
4
3
2
1
0
RO
1
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
WAITREQ[n]
Type
Reset
RO
1
RO
1
RO
1
RO
1
RO
1
RO
1
Bit/Field
Name
Type
31:0
WAITREQ[n]
RO
RO
1
Reset
RO
1
RO
1
Description
0xFFFF.FFC0 Channel [n] Wait Status
These bits provide the channel wait-on-request status. Bit 0 corresponds
to channel 0.
Value Description
1
The corresponding channel is waiting on a request.
0
The corresponding channel is not waiting on a request.
374
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 9: DMA Channel Software Request (DMASWREQ), offset 0x014
Each bit of the DMASWREQ register represents the corresponding μDMA channel. Setting a bit
generates a request for the specified μDMA channel.
DMA Channel Software Request (DMASWREQ)
Base 0x400F.F000
Offset 0x014
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
-
SWREQ[n]
Type
Reset
SWREQ[n]
Type
Reset
Bit/Field
Name
Type
Reset
31:0
SWREQ[n]
WO
-
WO
-
Description
Channel [n] Software Request
These bits generate software requests. Bit 0 corresponds to channel 0.
Value Description
1
Generate a software request for the corresponding channel.
0
No request generated.
These bits are automatically cleared when the software request has
been completed.
July 03, 2014
375
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 10: DMA Channel Useburst Set (DMAUSEBURSTSET), offset 0x018
Each bit of the DMAUSEBURSTSET register represents the corresponding μDMA channel. Setting
a bit disables the channel's single request input from generating requests, configuring the channel
to only accept burst requests. Reading the register returns the status of USEBURST.
If the amount of data to transfer is a multiple of the arbitration (burst) size, the corresponding SET[n]
bit is cleared after completing the final transfer. If there are fewer items remaining to transfer than
the arbitration (burst) size, the μDMA controller automatically clears the corresponding SET[n] bit,
allowing the remaining items to transfer using single requests. In order to resume transfers using
burst requests, the corresponding bit must be set again. A bit should not be set if the corresponding
peripheral does not support the burst request model.
Refer to “Request Types” on page 342 for more details about request types.
DMA Channel Useburst Set (DMAUSEBURSTSET)
Base 0x400F.F000
Offset 0x018
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
SET[n]
Type
Reset
SET[n]
Type
Reset
Bit/Field
Name
Type
31:0
SET[n]
R/W
Reset
Description
0x0000.0000 Channel [n] Useburst Set
Value Description
0
μDMA channel [n] responds to single or burst requests.
1
μDMA channel [n] responds only to burst requests.
Bit 0 corresponds to channel 0. This bit is automatically cleared as
described above. A bit can also be manually cleared by setting the
corresponding CLR[n] bit in the DMAUSEBURSTCLR register.
376
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 11: DMA Channel Useburst Clear (DMAUSEBURSTCLR), offset 0x01C
Each bit of the DMAUSEBURSTCLR register represents the corresponding μDMA channel. Setting
a bit clears the corresponding SET[n] bit in the DMAUSEBURSTSET register.
DMA Channel Useburst Clear (DMAUSEBURSTCLR)
Base 0x400F.F000
Offset 0x01C
Type WO, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
CLR[n]
Type
Reset
CLR[n]
Type
Reset
Bit/Field
Name
Type
Reset
31:0
CLR[n]
WO
-
Description
Channel [n] Useburst Clear
Value Description
0
No effect.
1
Setting a bit clears the corresponding SET[n] bit in the
DMAUSEBURSTSET register meaning that µDMA channel [n]
responds to single and burst requests.
July 03, 2014
377
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 12: DMA Channel Request Mask Set (DMAREQMASKSET), offset
0x020
Each bit of the DMAREQMASKSET register represents the corresponding μDMA channel. Setting
a bit disables μDMA requests for the channel. Reading the register returns the request mask status.
When a μDMA channel's request is masked, that means the peripheral can no longer request μDMA
transfers. The channel can then be used for software-initiated transfers.
DMA Channel Request Mask Set (DMAREQMASKSET)
Base 0x400F.F000
Offset 0x020
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
SET[n]
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
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
SET[n]
Type
Reset
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
R/W
0
Bit/Field
Name
Type
31:0
SET[n]
R/W
R/W
0
Reset
R/W
0
Description
0x0000.0000 Channel [n] Request Mask Set
Value Description
0
The peripheral associated with channel [n] is enabled to request
μDMA transfers.
1
The peripheral associated with channel [n] is not able to request
μDMA transfers. Channel [n] may be used for software-initiated
transfers.
Bit 0 corresponds to channel 0. A bit can only be cleared by setting the
corresponding CLR[n] bit in the DMAREQMASKCLR register.
378
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 13: DMA Channel Request Mask Clear (DMAREQMASKCLR), offset
0x024
Each bit of the DMAREQMASKCLR register represents the corresponding μDMA channel. Setting
a bit clears the corresponding SET[n] bit in the DMAREQMASKSET register.
DMA Channel Request Mask Clear (DMAREQMASKCLR)
Base 0x400F.F000
Offset 0x024
Type WO, reset 31
30
29
28
27
26
25
24
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
-
WO
-
CLR[n]
Type
Reset
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
15
14
13
12
11
10
9
8
CLR[n]
Type
Reset
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
Bit/Field
Name
Type
Reset
31:0
CLR[n]
WO
-
WO
-
Description
Channel [n] Request Mask Clear
Value Description
0
No effect.
1
Setting a bit clears the corresponding SET[n] bit in the
DMAREQMASKSET register meaning that the peripheral
associated with channel [n] is enabled to request μDMA
transfers.
July 03, 2014
379
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 14: DMA Channel Enable Set (DMAENASET), offset 0x028
Each bit of the DMAENASET register represents the corresponding µDMA channel. Setting a bit
enables the corresponding µDMA channel. Reading the register returns the enable status of the
channels. If a channel is enabled but the request mask is set (DMAREQMASKSET), then the
channel can be used for software-initiated transfers.
DMA Channel Enable Set (DMAENASET)
Base 0x400F.F000
Offset 0x028
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
SET[n]
Type
Reset
SET[n]
Type
Reset
Bit/Field
Name
Type
31:0
SET[n]
R/W
Reset
Description
0x0000.0000 Channel [n] Enable Set
Value Description
0
µDMA Channel [n] is disabled.
1
µDMA Channel [n] is enabled.
Bit 0 corresponds to channel 0. A bit can only be cleared by setting the
corresponding CLR[n] bit in the DMAENACLR register.
380
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 15: DMA Channel Enable Clear (DMAENACLR), offset 0x02C
Each bit of the DMAENACLR register represents the corresponding µDMA channel. Setting a bit
clears the corresponding SET[n] bit in the DMAENASET register.
DMA Channel Enable Clear (DMAENACLR)
Base 0x400F.F000
Offset 0x02C
Type WO, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
CLR[n]
Type
Reset
CLR[n]
Type
Reset
Bit/Field
Name
Type
Reset
31:0
CLR[n]
WO
-
Description
Clear Channel [n] Enable Clear
Value Description
0
No effect.
1
Setting a bit clears the corresponding SET[n] bit in the
DMAENASET register meaning that channel [n] is disabled for
μDMA transfers.
Note:
The controller disables a channel when it completes the μDMA
cycle.
July 03, 2014
381
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 16: DMA Channel Primary Alternate Set (DMAALTSET), offset 0x030
Each bit of the DMAALTSET register represents the corresponding µDMA channel. Setting a bit
configures the µDMA channel to use the alternate control data structure. Reading the register returns
the status of which control data structure is in use for the corresponding µDMA channel.
DMA Channel Primary Alternate Set (DMAALTSET)
Base 0x400F.F000
Offset 0x030
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
SET[n]
Type
Reset
SET[n]
Type
Reset
Bit/Field
Name
Type
31:0
SET[n]
R/W
Reset
Description
0x0000.0000 Channel [n] Alternate Set
Value Description
0
µDMA channel [n] is using the primary control structure.
1
µDMA channel [n] is using the alternate control structure.
Bit 0 corresponds to channel 0. A bit can only be cleared by setting the
corresponding CLR[n] bit in the DMAALTCLR register.
Note:
For Ping-Pong and Scatter-Gather cycle types, the µDMA
controller automatically sets these bits to select the alternate
channel control data structure.
382
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 17: DMA Channel Primary Alternate Clear (DMAALTCLR), offset
0x034
Each bit of the DMAALTCLR register represents the corresponding μDMA channel. Setting a bit
clears the corresponding SET[n] bit in the DMAALTSET register.
DMA Channel Primary Alternate Clear (DMAALTCLR)
Base 0x400F.F000
Offset 0x034
Type WO, reset 31
30
29
28
27
26
25
24
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
-
WO
-
CLR[n]
Type
Reset
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
15
14
13
12
11
10
9
8
CLR[n]
Type
Reset
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
Bit/Field
Name
Type
Reset
31:0
CLR[n]
WO
-
WO
-
Description
Channel [n] Alternate Clear
Value Description
0
No effect.
1
Setting a bit clears the corresponding SET[n] bit in the
DMAALTSET register meaning that channel [n] is using the
primary control structure.
Note:
For Ping-Pong and Scatter-Gather cycle types, the µDMA
controller automatically sets these bits to select the alternate
channel control data structure.
July 03, 2014
383
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 18: DMA Channel Priority Set (DMAPRIOSET), offset 0x038
Each bit of the DMAPRIOSET register represents the corresponding µDMA channel. Setting a bit
configures the µDMA channel to have a high priority level. Reading the register returns the status
of the channel priority mask.
DMA Channel Priority Set (DMAPRIOSET)
Base 0x400F.F000
Offset 0x038
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
SET[n]
Type
Reset
SET[n]
Type
Reset
Bit/Field
Name
Type
31:0
SET[n]
R/W
Reset
Description
0x0000.0000 Channel [n] Priority Set
Value Description
0
µDMA channel [n] is using the default priority level.
1
µDMA channel [n] is using a high priority level.
Bit 0 corresponds to channel 0. A bit can only be cleared by setting the
corresponding CLR[n] bit in the DMAPRIOCLR register.
384
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 19: DMA Channel Priority Clear (DMAPRIOCLR), offset 0x03C
Each bit of the DMAPRIOCLR register represents the corresponding µDMA channel. Setting a bit
clears the corresponding SET[n] bit in the DMAPRIOSET register.
DMA Channel Priority Clear (DMAPRIOCLR)
Base 0x400F.F000
Offset 0x03C
Type WO, reset 31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
WO
-
CLR[n]
Type
Reset
CLR[n]
Type
Reset
Bit/Field
Name
Type
Reset
31:0
CLR[n]
WO
-
Description
Channel [n] Priority Clear
Value Description
0
No effect.
1
Setting a bit clears the corresponding SET[n] bit in the
DMAPRIOSET register meaning that channel [n] is using the
default priority level.
July 03, 2014
385
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 20: DMA Bus Error Clear (DMAERRCLR), offset 0x04C
The DMAERRCLR register is used to read and clear the µDMA bus error status. The error status
is set if the μDMA controller encountered a bus error while performing a transfer. If a bus error
occurs on a channel, that channel is automatically disabled by the μDMA controller. The other
channels are unaffected.
DMA Bus Error Clear (DMAERRCLR)
Base 0x400F.F000
Offset 0x04C
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
Bit/Field
Name
Type
Reset
31:1
reserved
RO
0x0000.000
0
ERRCLR
R/W1C
0
RO
0
ERRCLR
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.
μDMA Bus Error Status
Value Description
0
No bus error is pending.
1
A bus error is pending.
This bit is cleared by writing a 1 to it.
386
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 21: DMA Channel Assignment (DMACHASGN), offset 0x500
Each bit of the DMACHASGN register represents the corresponding µDMA channel. Setting a bit
selects the secondary channel assignment as specified in Table 7-1 on page 340.
DMA Channel Assignment (DMACHASGN)
Base 0x400F.F000
Offset 0x500
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
23
22
21
20
19
18
17
16
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
7
6
5
4
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
CHASGN[n]
Type
Reset
CHASGN[n]
Type
Reset
Bit/Field
Name
Type
Reset
31:0
CHASGN[n]
R/W
-
R/W
-
Description
Channel [n] Assignment Select
Value Description
0
Use the primary channel assignment.
1
Use the secondary channel assignment.
July 03, 2014
387
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 22: DMA Peripheral Identification 0 (DMAPeriphID0), offset 0xFE0
The DMAPeriphIDn registers are hard-coded, and the fields within the registers determine the reset
values.
DMA Peripheral Identification 0 (DMAPeriphID0)
Base 0x400F.F000
Offset 0xFE0
Type RO, reset 0x0000.0030
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
1
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PID0
RO
0x30
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.
μDMA Peripheral ID Register [7:0]
Can be used by software to identify the presence of this peripheral.
388
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 23: DMA Peripheral Identification 1 (DMAPeriphID1), offset 0xFE4
The DMAPeriphIDn registers are hard-coded, and the fields within the registers determine the reset
values.
DMA Peripheral Identification 1 (DMAPeriphID1)
Base 0x400F.F000
Offset 0xFE4
Type RO, reset 0x0000.00B2
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
1
RO
0
reserved
Type
Reset
reserved
Type
Reset
PID1
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PID1
RO
0xB2
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.
μDMA Peripheral ID Register [15:8]
Can be used by software to identify the presence of this peripheral.
July 03, 2014
389
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 24: DMA Peripheral Identification 2 (DMAPeriphID2), offset 0xFE8
The DMAPeriphIDn registers are hard-coded, and the fields within the registers determine the reset
values.
DMA Peripheral Identification 2 (DMAPeriphID2)
Base 0x400F.F000
Offset 0xFE8
Type RO, reset 0x0000.000B
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
0
RO
1
RO
1
reserved
Type
Reset
reserved
Type
Reset
PID2
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PID2
RO
0x0B
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.
μDMA Peripheral ID Register [23:16]
Can be used by software to identify the presence of this peripheral.
390
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 25: DMA Peripheral Identification 3 (DMAPeriphID3), offset 0xFEC
The DMAPeriphIDn registers are hard-coded and the fields within the registers determine the reset
values.
DMA Peripheral Identification 3 (DMAPeriphID3)
Base 0x400F.F000
Offset 0xFEC
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
PID3
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PID3
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.
μDMA Peripheral ID Register [31:24]
Can be used by software to identify the presence of this peripheral.
July 03, 2014
391
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 26: DMA Peripheral Identification 4 (DMAPeriphID4), offset 0xFD0
The DMAPeriphIDn registers are hard-coded, and the fields within the registers determine the reset
values.
DMA Peripheral Identification 4 (DMAPeriphID4)
Base 0x400F.F000
Offset 0xFD0
Type RO, reset 0x0000.0004
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
0
reserved
Type
Reset
reserved
Type
Reset
PID4
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PID4
RO
0x04
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.
μDMA Peripheral ID Register
Can be used by software to identify the presence of this peripheral.
392
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 27: DMA PrimeCell Identification 0 (DMAPCellID0), offset 0xFF0
The DMAPCellIDn registers are hard-coded, and the fields within the registers determine the reset
values.
DMA PrimeCell Identification 0 (DMAPCellID0)
Base 0x400F.F000
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
0x0000.00
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.
μDMA PrimeCell ID Register [7:0]
Provides software a standard cross-peripheral identification system.
July 03, 2014
393
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 28: DMA PrimeCell Identification 1 (DMAPCellID1), offset 0xFF4
The DMAPCellIDn registers are hard-coded, and the fields within the registers determine the reset
values.
DMA PrimeCell Identification 1 (DMAPCellID1)
Base 0x400F.F000
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
0x0000.00
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.
μDMA PrimeCell ID Register [15:8]
Provides software a standard cross-peripheral identification system.
394
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 29: DMA PrimeCell Identification 2 (DMAPCellID2), offset 0xFF8
The DMAPCellIDn registers are hard-coded, and the fields within the registers determine the reset
values.
DMA PrimeCell Identification 2 (DMAPCellID2)
Base 0x400F.F000
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
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID2
RO
0x05
μDMA PrimeCell ID Register [23:16]
Provides software a standard cross-peripheral identification system.
July 03, 2014
395
Texas Instruments-Production Data
Micro Direct Memory Access (μDMA)
Register 30: DMA PrimeCell Identification 3 (DMAPCellID3), offset 0xFFC
The DMAPCellIDn registers are hard-coded, and the fields within the registers determine the reset
values.
DMA PrimeCell Identification 3 (DMAPCellID3)
Base 0x400F.F000
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
Description
31:8
reserved
RO
0x00
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
7:0
CID3
RO
0xB1
μDMA PrimeCell ID Register [31:24]
Provides software a standard cross-peripheral identification system.
396
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
8
General-Purpose Input/Outputs (GPIOs)
The GPIO module is composed of nine physical GPIO blocks, each corresponding to an individual
GPIO port (Port A, Port B, Port C, Port D, Port E, Port F, Port G, Port H, Port J). The GPIO module
supports up to 72 programmable input/output pins, depending on the peripherals being used.
The GPIO module has the following features:
■ Up to 72 GPIOs, depending on configuration
■ Highly flexible pin muxing allows use as GPIO or one of several peripheral functions
■ 5-V-tolerant in input configuration
■ Two means of port access: either Advanced High-Performance Bus (AHB) with better back-to-back
access performance, or the legacy Advanced Peripheral Bus (APB) for backwards-compatibility
with existing code
■ Fast toggle capable of a change every clock cycle for ports on AHB, every two clock cycles for
ports on APB
■ Programmable control for GPIO interrupts
– Interrupt generation masking
– Edge-triggered on rising, falling, or both
– Level-sensitive on High or Low values
■ Bit masking in both read and write operations through address lines
■ Can be used to initiate an ADC sample sequence
■ Pins configured as digital inputs are Schmitt-triggered
■ Programmable control for GPIO pad configuration
– Weak pull-up or pull-down resistors
– 2-mA, 4-mA, and 8-mA pad drive for digital communication; up to four pads can sink 18-mA
for high-current applications
– Slew rate control for the 8-mA drive
– Open drain enables
– Digital input enables
8.1
Signal Description
GPIO signals have alternate hardware functions. The following table lists the GPIO pins and their
analog and digital alternate functions. The AINx and VREFA analog signals are not 5-V tolerant and
go through an isolation circuit before reaching their circuitry. These signals are configured by clearing
the corresponding DEN bit in the GPIO Digital Enable (GPIODEN) register and setting the
corresponding AMSEL bit in the GPIO Analog Mode Select (GPIOAMSEL) register. Other analog
July 03, 2014
397
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
signals are 5-V tolerant and are connected directly to their circuitry (C0-, C0+, C1-, C1+, C2-, C2+,
USB0VBUS, USB0ID). These signals are configured by clearing the DEN bit in the GPIO Digital
Enable (GPIODEN) register. All GPIO signals are 5-V tolerant when configured as inputs except
for PB0 and PB1, which are limited to 3.6 V. The digital alternate hardware functions are enabled
by setting the appropriate bit in the GPIO Alternate Function Select (GPIOAFSEL) and GPIODEN
registers and configuring the PMCx bit field in the GPIO Port Control (GPIOPCTL) register to the
numeric encoding shown in the table below. Note that each pin must be programmed individually;
no type of grouping is implied by the columns in the table. Table entries that are shaded gray are
the default values for the corresponding GPIO pin.
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 8-1. GPIO Pins With Non-Zero Reset Values
GPIO Pins
Default State
PA[1:0]
UART0
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR
0
0
0
GPIOPCTL
0
0x1
PA[5:2]
SSI0
0
0
0
0
0x1
PB[3:2]
I2C0
0
0
0
0
0x1
PC[3:0]
JTAG/SWD
1
1
0
1
0x3
Table 8-2. GPIO Pins and Alternate Functions (100LQFP)
IO
Pin
Analog
Function
a
Digital Function (GPIOPCTL PMCx Bit Field Encoding)
1
2
3
4
5
6
7
8
9
10
11
PA0
26
-
U0Rx
-
-
-
-
-
-
I2C1SCL
U1Rx
-
-
PA1
27
-
U0Tx
-
-
-
-
-
-
I2C1SDA
U1Tx
-
-
PA2
28
-
SSI0Clk
-
-
PWM4
-
-
-
-
I2S0RXSD
-
-
PA3
29
-
SSI0Fss
-
-
PWM5
-
-
-
-
I2S0RXMCLK
-
-
PA4
30
-
SSI0Rx
-
-
PWM6
CAN0Rx
-
-
-
I2S0TXSCK
-
-
PA5
31
-
SSI0Tx
-
-
PWM7
CAN0Tx
-
-
-
I2S0TXWS
-
-
PA6
34
-
I2C1SCL
CCP1
-
PWM0
PWM4
CAN0Rx
-
USB0EPEN U1CTS
-
-
USB0PFLT U1DCD
PA7
35
-
I2C1SDA
CCP4
-
PWM1
PWM5
CAN0Tx
CCP3
-
-
PB0
66
USB0ID
CCP0
PWM2
-
-
U1Rx
-
-
-
-
-
-
PB1
67
USB0VBUS
CCP2
PWM3
-
CCP1
U1Tx
-
-
-
-
-
-
IDX0
PB2
72
-
I2C0SCL
PB3
65
-
I2C0SDA Fault0
PB4
92
AIN10
C0-
-
PB5
91
AIN11
C1-
PB6
90
PB7
PC0
-
CCP3
CCP0
-
-
USB0EPEN
-
-
-
-
Fault3
-
-
-
USB0PFLT
-
-
-
-
-
U2Rx
CAN0Rx
IDX0
U1Rx
EPI0S23
-
-
-
C0o
CCP5
CCP6
CCP0
CAN0Tx
CCP2
U1Tx
EPI0S22
-
-
-
VREFA
C0+
CCP1
CCP7
C0o
Fault1
IDX0
CCP5
-
-
I2S0TXSCK
-
-
89
-
-
-
-
NMI
-
-
-
-
-
-
-
80
-
-
-
TCK
SWCLK
-
-
-
-
-
-
-
-
398
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 8-2. GPIO Pins and Alternate Functions (100LQFP) (continued)
IO
Pin
Analog
Function
PC1
79
-
PC2
78
-
PC3
77
-
PC4
25
PC5
PC6
a
Digital Function (GPIOPCTL PMCx Bit Field Encoding)
1
2
3
4
5
6
7
8
9
10
11
-
-
TMS
SWDIO
-
-
-
-
-
-
-
-
-
-
TDI
-
-
-
-
-
-
-
-
-
-
TDO
SWO
-
-
-
-
-
-
-
-
-
CCP5
PhA0
-
PWM6
CCP2
CCP4
-
EPI0S2
CCP1
-
-
24
C1+
CCP1
C1o
C0o
Fault2
CCP3
USB0EPEN
-
EPI0S3
-
-
-
23
C2+
CCP3
PhB0
C2o
PWM7
U1Rx
CCP0
USB0PFLT EPI0S4
-
-
-
PC7
22
C2-
CCP4
PhB0
-
CCP0
U1Tx
USB0PFLT
C1o
-
-
-
PD0
10
AIN15
PWM0
CAN0Rx
IDX0
U2Rx
U1Rx
CCP6
-
I2S0RXSCK U1CTS
-
-
PD1
11
AIN14
PWM1
CAN0Tx
PhA0
U2Tx
U1Tx
CCP7
-
I2S0RXWS U1DCD
CCP2
PhB1
PD2
12
AIN13
U1Rx
CCP6
PWM2
CCP5
-
-
-
EPI0S20
-
-
PD3
13
AIN12
U1Tx
CCP7
PWM3
CCP0
-
-
-
EPI0S21
-
-
-
PD4
97
AIN7
CCP0
CCP3
-
-
-
-
-
I2S0RXSD
U1RI
EPI0S19
-
EPI0S5
-
PD5
98
AIN6
CCP2
CCP4
-
-
-
-
-
I2S0RXMCLK
U2Rx
EPI0S28
-
PD6
99
AIN5
Fault0
-
-
-
-
-
-
I2S0TXSCK
U2Tx
EPI0S29
-
PD7
100
AIN4
IDX0
C0o
CCP1
-
-
-
-
I2S0TXWS U1DTR
EPI0S30
-
CCP3
-
-
-
-
EPI0S8 USB0PFLT
-
-
CCP2
CCP6
-
-
EPI0S9
-
-
PE0
74
-
PWM4
SSI1Clk
PE1
75
-
PWM5
SSI1Fss Fault0
-
PE2
95
AIN9
CCP4
SSI1Rx
PhB1
PhA0
CCP2
-
-
EPI0S24
-
-
-
PE3
96
AIN8
CCP1
SSI1Tx
PhA1
PhB0
CCP7
-
-
EPI0S25
-
-
-
PE4
6
AIN3
CCP3
-
-
Fault0
U2Tx
CCP2
-
-
I2S0TXWS
-
-
PE5
5
AIN2
CCP5
-
-
-
-
-
-
-
I2S0TXSD
-
-
PE6
2
AIN1
PWM4
C1o
-
-
-
-
-
-
U1CTS
-
-
PE7
1
AIN0
PWM5
C2o
-
-
-
-
-
-
U1DCD
-
-
PF0
47
-
CAN1Rx
PhB0
PWM0
-
-
-
-
I2S0TXSD U1DSR
-
-
PF1
61
-
CAN1Tx
IDX1
PWM1
-
-
-
-
I2S0TXMCLK U1RTS
CCP3
-
PF2
60
-
-
PWM4
-
PWM2
-
-
-
-
SSI1Clk
-
-
PF3
59
-
-
PWM5
-
PWM3
-
-
-
-
SSI1Fss
-
-
PF4
58
-
CCP0
C0o
-
Fault0
-
-
-
EPI0S12 SSI1Rx
-
-
PF5
46
-
CCP2
C1o
-
-
-
-
-
EPI0S15 SSI1Tx
-
-
PF6
43
-
CCP1
C2o
-
PhA0
-
-
-
PF7
42
-
CCP4
-
-
PhB0
-
-
PG0
19
-
U2Rx
PWM0
I2C1SCL
PWM4
-
-
-
-
I2S0TXMCLK U1RTS
-
-
-
-
-
-
-
EPI0S12 Fault1
USB0EPEN EPI0S13
-
PG1
18
-
U2Tx
PWM1
I2C1SDA
PWM5
-
-
-
EPI0S14
-
PG2
17
-
PWM0
-
-
Fault0
-
-
-
IDX1
I2S0RXSD
-
-
PG3
16
-
PWM1
-
-
Fault2
-
-
-
Fault0 I2S0RXMCLK
-
-
PG4
41
-
CCP3
-
-
Fault1
-
-
-
EPI0S15
PG5
40
-
CCP5
-
-
IDX0
Fault1
-
-
PWM7
PG6
37
-
PhA1
-
-
PWM6
-
-
-
PG7
36
-
PhB1
-
-
PWM7
-
-
-
July 03, 2014
U1RI
-
I2S0RXSCK U1DTR
-
PWM6
Fault1 I2S0RXWS
CCP5
EPI0S31
U1RI
-
-
-
399
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Table 8-2. GPIO Pins and Alternate Functions (100LQFP) (continued)
a
Digital Function (GPIOPCTL PMCx Bit Field Encoding)
IO
Pin
Analog
Function
1
2
3
4
5
6
7
8
9
10
11
PH0
86
-
CCP6
PWM2
-
-
-
-
-
EPI0S6
PWM4
-
-
PH1
85
-
CCP7
PWM3
-
-
-
-
-
EPI0S7
PWM5
-
-
PH2
84
-
IDX1
C1o
-
Fault3
-
-
-
EPI0S1
-
-
-
PH3
83
-
PhB0
Fault0
-
USB0EPEN
-
-
-
EPI0S0
-
-
-
PH4
76
-
-
-
-
USB0PFLT
-
-
-
EPI0S10
-
-
SSI1Clk
PH5
63
-
-
-
-
-
-
-
-
EPI0S11
-
PH6
62
-
-
-
-
-
-
-
-
EPI0S26
-
PWM4
PH7
15
-
-
-
-
-
-
-
-
EPI0S27
-
PWM5
SSI1Tx
PJ0
14
-
-
-
-
-
-
-
-
EPI0S16
-
PWM0
I2C1SCL
PJ1
87
-
-
-
-
-
-
-
-
EPI0S17 USB0PFLT
PJ2
39
-
-
-
-
-
-
-
-
EPI0S18
PJ3
50
-
-
-
-
-
-
-
-
PJ4
52
-
-
-
-
-
-
-
PJ5
53
-
-
-
-
-
-
-
PJ6
54
-
-
-
-
-
-
PJ7
55
-
-
-
-
-
-
Fault2 SSI1Fss
SSI1Rx
PWM1
I2C1SDA
Fault0
-
EPI0S19 U1CTS
CCP6
-
-
EPI0S28 U1DCD
CCP4
-
-
EPI0S29 U1DSR
CCP2
-
-
-
EPI0S30 U1RTS
CCP1
-
-
-
CCP0
-
10
11
-
CCP0
U1DTR
a. The digital signals that are shaded gray are the power-on default values for the corresponding GPIO pin.
Table 8-3. GPIO Pins and Alternate Functions (108BGA)
IO
Pin
Analog
Function
a
Digital Function (GPIOPCTL PMCx Bit Field Encoding)
1
2
3
4
5
6
7
8
9
PA0
L3
-
U0Rx
-
-
-
-
-
-
I2C1SCL
U1Rx
-
-
PA1
M3
-
U0Tx
-
-
-
-
-
-
I2C1SDA
U1Tx
-
-
PA2
M4
-
SSI0Clk
-
-
PWM4
-
-
-
-
I2S0RXSD
-
-
PA3
L4
-
SSI0Fss
-
-
PWM5
-
-
-
-
I2S0RXMCLK
-
-
PA4
L5
-
SSI0Rx
-
-
PWM6
CAN0Rx
-
-
-
I2S0TXSCK
-
-
PA5
M5
-
SSI0Tx
-
-
PWM7
CAN0Tx
-
-
-
I2S0TXWS
-
-
PA6
L6
-
I2C1SCL
CCP1
-
PWM0
PWM4
CAN0Rx
-
USB0EPEN U1CTS
-
-
USB0PFLT U1DCD
-
-
PA7
M6
-
I2C1SDA
CCP4
-
PWM1
PWM5
CAN0Tx
CCP3
PB0
E12
USB0ID
CCP0
PWM2
-
-
U1Rx
-
-
-
-
-
-
PB1
D12
USB0VBUS
CCP2
PWM3
-
CCP1
U1Tx
-
-
-
-
-
-
IDX0
PB2
A11
-
I2C0SCL
PB3
E11
-
I2C0SDA Fault0
PB4
A6
AIN10
C0-
-
PB5
B7
AIN11
C1-
PB6
A7
PB7
A8
-
CCP3
CCP0
-
-
USB0EPEN
-
-
-
-
Fault3
-
-
-
USB0PFLT
-
-
-
-
-
U2Rx
CAN0Rx
IDX0
U1Rx
EPI0S23
-
-
-
C0o
CCP5
CCP6
CCP0
CAN0Tx
CCP2
U1Tx
EPI0S22
-
-
-
VREFA
C0+
CCP1
CCP7
C0o
Fault1
IDX0
CCP5
-
-
I2S0TXSCK
-
-
-
-
-
-
NMI
-
-
-
-
-
-
-
400
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 8-3. GPIO Pins and Alternate Functions (108BGA) (continued)
IO
Pin
Analog
Function
PC0
A9
-
PC1
B9
-
PC2
B8
-
PC3
A10
-
PC4
L1
PC5
a
Digital Function (GPIOPCTL PMCx Bit Field Encoding)
1
2
3
4
5
6
7
8
9
10
11
-
-
TCK
SWCLK
-
-
-
-
-
-
-
-
-
-
TMS
SWDIO
-
-
-
-
-
-
-
-
-
-
TDI
-
-
-
-
-
-
-
-
-
-
TDO
SWO
-
-
-
-
-
-
-
-
-
CCP5
PhA0
-
PWM6
CCP2
CCP4
-
EPI0S2
CCP1
-
-
M1
C1+
CCP1
C1o
C0o
Fault2
CCP3
USB0EPEN
-
EPI0S3
-
-
-
PC6
M2
C2+
CCP3
PhB0
C2o
PWM7
U1Rx
CCP0
USB0PFLT EPI0S4
-
-
-
PC7
L2
C2-
CCP4
PhB0
-
CCP0
U1Tx
USB0PFLT
C1o
-
-
-
PD0
G1
AIN15
PWM0
CAN0Rx
IDX0
U2Rx
U1Rx
CCP6
-
I2S0RXSCK U1CTS
-
-
PD1
G2
AIN14
PWM1
CAN0Tx
PhA0
U2Tx
U1Tx
CCP7
-
I2S0RXWS U1DCD
CCP2
PhB1
PD2
H2
AIN13
U1Rx
CCP6
PWM2
CCP5
-
-
-
EPI0S20
-
-
EPI0S5
-
PD3
H1
AIN12
U1Tx
CCP7
PWM3
CCP0
-
-
-
EPI0S21
-
-
-
PD4
B5
AIN7
CCP0
CCP3
-
-
-
-
-
I2S0RXSD
U1RI
EPI0S19
-
PD5
C6
AIN6
CCP2
CCP4
-
-
-
-
-
I2S0RXMCLK
U2Rx
EPI0S28
PD6
A3
AIN5
Fault0
-
-
-
-
-
-
I2S0TXSCK
U2Tx
EPI0S29
-
PD7
A2
AIN4
IDX0
C0o
CCP1
-
-
-
-
I2S0TXWS U1DTR
EPI0S30
-
CCP3
PE0
B11
-
PWM4
SSI1Clk
-
-
-
-
EPI0S8 USB0PFLT
-
-
PE1
A12
-
PWM5
SSI1Fss Fault0
CCP2
CCP6
-
-
EPI0S9
-
-
-
PE2
A4
AIN9
CCP4
SSI1Rx
PhB1
PhA0
CCP2
-
-
EPI0S24
-
-
-
PE3
B4
AIN8
CCP1
SSI1Tx
PhA1
PhB0
CCP7
-
-
EPI0S25
-
-
-
PE4
B2
AIN3
CCP3
-
-
Fault0
U2Tx
CCP2
-
-
I2S0TXWS
-
-
PE5
B3
AIN2
CCP5
-
-
-
-
-
-
-
I2S0TXSD
-
-
PE6
A1
AIN1
PWM4
C1o
-
-
-
-
-
-
U1CTS
-
-
PE7
B1
AIN0
PWM5
C2o
-
-
-
-
-
-
U1DCD
-
-
PF0
M9
-
CAN1Rx
PhB0
PWM0
-
-
-
-
I2S0TXSD U1DSR
-
-
PF1
H12
-
CAN1Tx
IDX1
PWM1
-
-
-
-
I2S0TXMCLK U1RTS
CCP3
-
PF2
J11
-
-
PWM4
-
PWM2
-
-
-
-
SSI1Clk
-
-
PF3
J12
-
-
PWM5
-
PWM3
-
-
-
-
SSI1Fss
-
-
PF4
L9
-
CCP0
C0o
-
Fault0
-
-
-
EPI0S12 SSI1Rx
-
-
PF5
L8
-
CCP2
C1o
-
-
-
-
-
EPI0S15 SSI1Tx
-
-
PF6
M8
-
CCP1
C2o
-
PhA0
-
-
-
PF7
K4
-
CCP4
-
-
PhB0
-
-
PG0
K1
-
U2Rx
PWM0
I2C1SCL
PWM4
-
-
PG1
K2
-
U2Tx
PWM1
I2C1SDA
PWM5
-
-
-
-
-
-
-
-
-
-
EPI0S14
-
-
-
IDX1
EPI0S12 Fault1
USB0EPEN EPI0S13
-
I2S0TXMCLK U1RTS
PG2
J1
-
PWM0
-
-
Fault0
-
-
-
I2S0RXSD
-
-
PG3
J2
-
PWM1
-
-
Fault2
-
-
-
Fault0 I2S0RXMCLK
-
-
PG4
K3
-
CCP3
-
-
Fault1
-
-
-
EPI0S15
PG5
M7
-
CCP5
-
-
IDX0
Fault1
-
-
PWM7
July 03, 2014
U1RI
-
I2S0RXSCK U1DTR
-
PWM6
401
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Table 8-3. GPIO Pins and Alternate Functions (108BGA) (continued)
a
Digital Function (GPIOPCTL PMCx Bit Field Encoding)
IO
Pin
Analog
Function
1
2
3
4
5
6
7
PG6
L7
-
PhA1
-
-
PWM6
-
-
-
PG7
C10
-
PhB1
-
-
PWM7
-
-
-
CCP5
PH0
C9
-
CCP6
PWM2
-
-
-
-
-
PH1
C8
-
CCP7
PWM3
-
-
-
-
-
PH2
D11
-
IDX1
C1o
-
Fault3
-
-
PH3
D10
-
PhB0
Fault0
-
USB0EPEN
-
-
PH4
B10
-
-
-
-
USB0PFLT
-
PH5
F10
-
-
-
-
-
PH6
G3
-
-
-
-
-
PH7
H3
-
-
-
-
PJ0
F3
-
-
-
-
PJ1
B6
-
-
-
PJ2
K6
-
-
PJ3
M10
-
-
PJ4
K11
-
PJ5
K12
-
PJ6
L10
PJ7
L12
8
9
10
11
U1RI
-
EPI0S31
-
-
EPI0S6
PWM4
-
-
EPI0S7
PWM5
-
-
-
EPI0S1
-
-
-
-
EPI0S0
-
-
-
-
-
EPI0S10
-
-
SSI1Clk
-
-
-
EPI0S11
-
-
-
-
EPI0S26
-
PWM4
-
-
-
-
EPI0S27
-
PWM5
SSI1Tx
-
-
-
-
EPI0S16
-
PWM0
I2C1SCL
-
-
-
-
-
EPI0S17 USB0PFLT
PWM1
I2C1SDA
-
-
-
-
-
-
EPI0S18
Fault0
-
-
-
-
-
-
-
EPI0S19 U1CTS
CCP6
-
-
-
-
-
-
-
-
EPI0S28 U1DCD
CCP4
-
-
-
-
-
-
-
-
EPI0S29 U1DSR
CCP2
-
-
-
-
-
-
-
-
-
EPI0S30 U1RTS
CCP1
-
-
-
-
-
-
-
-
-
CCP0
-
Fault1 I2S0RXWS
-
CCP0
U1DTR
Fault2 SSI1Fss
SSI1Rx
a. The digital signals that are shaded gray are the power-on default values for the corresponding GPIO pin.
8.2
Functional Description
Each GPIO port is a separate hardware instantiation of the same physical block (see Figure
8-1 on page 403 and Figure 8-2 on page 404). The LM3S5791 microcontroller contains nine ports
and thus nine of these physical GPIO blocks. Note that not all pins may be implemented on every
block. Some GPIO pins can function as I/O signals for the on-chip peripheral modules. For information
on which GPIO pins are used for alternate hardware functions, refer to Table 23-5 on page 1199.
402
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 8-1. Digital I/O Pads
Commit
Control
GPIOLOCK
GPIOCR
Port
Control
GPIOPCTL
Mode
Control
GPIOAFSEL
Periph 1
DEMUX
Alternate Input
Alternate Output
Alternate Output Enable
MUX
Periph 0
Pad Input
Periph n
GPIO Output
GPIO Output Enable
Interrupt
Control
Pad
Control
GPIOIS
GPIOIBE
GPIOIEV
GPIOIM
GPIORIS
GPIOMIS
GPIOICR
GPIODR2R
GPIODR4R
GPIODR8R
GPIOSLR
GPIOPUR
GPIOPDR
GPIOODR
GPIODEN
MUX
GPIODATA
GPIODIR
Interrupt
MUX
GPIO Input
Data
Control
Pad Output
Digital
I/O
Pad
Package I/O Pin
Pad Output
Enable
Identification Registers
GPIOPeriphID0
GPIOPeriphID1
GPIOPeriphID2
GPIOPeriphID3
GPIOPeriphID4
GPIOPeriphID5
GPIOPeriphID6
GPIOPeriphID7
GPIOPCellID0
GPIOPCellID1
GPIOPCellID2
GPIOPCellID3
July 03, 2014
403
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Figure 8-2. Analog/Digital I/O Pads
Commit
Control
GPIOLOCK
GPIOCR
Port
Control
GPIOPCTL
Mode
Control
GPIOAFSEL
Periph 1
DEMUX
Alternate Input
Alternate Output
Alternate Output Enable
MUX
Periph 0
Pad Input
Periph n
MUX
MUX
Data
Control
Pad Output
Pad Output Enable
Analog/Digital
I/O Pad
Package I/O Pin
GPIO Input
GPIO Output
GPIODATA
GPIODIR
Interrupt
GPIO Output Enable
Interrupt
Control
GPIOIS
GPIOIBE
GPIOIEV
GPIOIM
GPIORIS
GPIOMIS
GPIOICR
Pad
Control
GPIODR2R
GPIODR4R
GPIODR8R
GPIOSLR
GPIOPUR
GPIOPDR
GPIOODR
GPIODEN
GPIOAMSEL
Analog Circuitry
Identification Registers
GPIOPeriphID0
GPIOPeriphID1
GPIOPeriphID2
GPIOPeriphID3
8.2.1
GPIOPeriphID4
GPIOPeriphID5
GPIOPeriphID6
GPIOPeriphID7
GPIOPCellID0
GPIOPCellID1
GPIOPCellID2
GPIOPCellID3
ADC
(for GPIO pins that
connect to the ADC
input MUX)
Isolation
Circuit
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.
Caution – 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. As a result, the debugger may be locked out of
the part. This issue can be avoided with a software routine that restores JTAG functionality based on
an external or software trigger.
8.2.1.1
Data Direction Operation
The GPIO Direction (GPIODIR) register (see page 412) is used to configure each individual pin as
an input or output. When the data direction bit is cleared, the GPIO is configured as an input, and
the corresponding data register bit captures and stores the value on the GPIO port. When the data
direction bit is set, the GPIO is configured as an output, and the corresponding data register bit is
driven out on the GPIO port.
404
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
8.2.1.2
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 411) by using bits [9:2] of the address bus as a mask.
In this manner, software drivers can modify individual GPIO pins in a single instruction without
affecting the state of the other pins. This method is more efficient than the conventional method of
performing a read-modify-write operation to set or clear an individual GPIO pin. To implement 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, the value of the GPIODATA
register is altered. If the address bit is cleared, the data bit is left unchanged.
For example, writing a value of 0xEB to the address GPIODATA + 0x098 has the results shown in
Figure 8-3, where u indicates that data is unchanged by the write.
Figure 8-3. 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
0
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, the value is read. If the address
bit associated with the data bit is cleared, the data bit is read as a zero, regardless of its actual
value. For example, reading address GPIODATA + 0x0C4 yields as shown in Figure 8-4.
Figure 8-4. GPIODATA Read Example
8.2.2
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. These registers
are used 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, the external source must hold the level constant
for the interrupt to be recognized by the controller.
Three registers define the edge or sense that causes interrupts:
■ GPIO Interrupt Sense (GPIOIS) register (see page 413)
July 03, 2014
405
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
■ GPIO Interrupt Both Edges (GPIOIBE) register (see page 414)
■ GPIO Interrupt Event (GPIOIEV) register (see page 415)
Interrupts are enabled/disabled via the GPIO Interrupt Mask (GPIOIM) register (see page 416).
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 417 and page 418). As the name implies, the GPIOMIS register only shows interrupt
conditions that are allowed to be passed to the interrupt controller. The GPIORIS register indicates
that a GPIO pin meets the conditions for an interrupt, but has not necessarily been sent to the
interrupt controller.
Interrupts are cleared by writing a 1 to the appropriate bit of the GPIO Interrupt Clear (GPIOICR)
register (see page 420).
When programming the interrupt control registers (GPIOIS, GPIOIBE, or GPIOIEV), the interrupts
should be masked (GPIOIM cleared). Writing any value to an interrupt control register can generate
a spurious interrupt if the corresponding bits are enabled.
8.2.2.1
ADC Trigger Source
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 (the appropriate bit of GPIOIM is set), an interrupt
for Port B is generated, and 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. See page 631.
If no other Port B pins are being used to generate interrupts, the Interrupt 0-31 Set Enable (EN0)
register can disable the Port B interrupts, and the ADC interrupt can be used to read back the
converted data. Otherwise, the Port B interrupt handler must ignore and clear interrupts on PB4 and
wait for the ADC interrupt, or the ADC interrupt must be disabled in the EN0 register and the Port
B interrupt handler must poll the ADC registers until the conversion is completed. See page 133 for
more information.
8.2.3
Mode Control
The GPIO pins can be controlled by either software or hardware. Software control is the default for
most signals and corresponds to the GPIO mode, where the GPIODATA register is used to read
or write the corresponding pins. When hardware control is enabled via the GPIO Alternate Function
Select (GPIOAFSEL) register (see page 421), the pin state is controlled by its alternate function
(that is, the peripheral).
Further pin muxing options are provided through the GPIO Port Control (GPIOPCTL) register which
selects one of several peripheral functions for each GPIO. For information on the configuration
options, refer to Table 23-5 on page 1199.
Note:
8.2.4
If any pin is to be used as an ADC input, the appropriate bit in the GPIOAMSEL register
must be set to disable the analog isolation circuit.
Commit Control
The GPIO commit control registers provide a layer of protection against accidental programming of
critical hardware peripherals. Protection is provided for the NMI pin (PB7) and the four JTAG/SWD
pins (PC[3:0]). Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL)
register (see page 421), GPIO Pull Up Select (GPIOPUR) register (see page 427), GPIO Pull-Down
Select (GPIOPDR) register (see page 429), and GPIO Digital Enable (GPIODEN) register (see
406
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
page 432) are not committed to storage unless the GPIO Lock (GPIOLOCK) register (see page 434)
has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register (see page 435)
have been set.
8.2.5
Pad Control
The pad control registers allow software to configure the GPIO pads based on the application
requirements. The pad control registers include the GPIODR2R, GPIODR4R, GPIODR8R, GPIOODR,
GPIOPUR, GPIOPDR, GPIOSLR, and GPIODEN registers. These registers control drive strength,
open-drain configuration, pull-up and pull-down resistors, slew-rate control and digital input enable
for each GPIO.
8.2.6
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.
8.3
Initialization and Configuration
The GPIO modules may be accessed via two different memory apertures. The legacy aperture, the
Advanced Peripheral Bus (APB), is backwards-compatible with previous Stellaris parts. The other
aperture, the Advanced High-Performance Bus (AHB), offers the same register map but provides
better back-to-back access performance than the APB bus. These apertures are mutually exclusive.
The aperture enabled for a given GPIO port is controlled by the appropriate bit in the GPIOHBCTL
register (see page 231).
To use the pins in a particular GPIO port, the clock for the port must be enabled by setting the
appropriate GPIO Port bit field (GPIOn) in the RCGC2 register (see page 288).
When the internal POR signal is asserted and until otherwise configured, all GPIO pins are configured
to be undriven (tristate): GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0, and GPIOPUR=0, except for
the pins shown in Table 8-1 on page 398. Table 8-4 on page 407 shows all possible configurations
of the GPIO pads and the control register settings required to achieve them. Table 8-5 on page 408
shows how a rising edge interrupt is configured for pin 2 of a GPIO port.
Table 8-4. GPIO Pad Configuration Examples
a
Configuration
GPIO Register Bit Value
AFSEL
DIR
ODR
DEN
PUR
PDR
DR2R
DR4R
DR8R
SLR
Digital Input (GPIO)
0
0
0
1
?
?
X
X
X
X
Digital Output (GPIO)
0
1
0
1
?
?
?
?
?
?
Open Drain Output
(GPIO)
0
1
1
1
X
X
?
?
?
?
Open Drain
Input/Output (I2C)
1
X
1
1
X
X
?
?
?
?
Digital Input (Timer
CCP)
1
X
0
1
?
?
X
X
X
X
Digital Input (QEI)
1
X
0
1
?
?
X
X
X
X
Digital Output (PWM)
1
X
0
1
?
?
?
?
?
?
Digital Output (Timer
PWM)
1
X
0
1
?
?
?
?
?
?
Digital Input/Output
(SSI)
1
X
0
1
?
?
?
?
?
?
July 03, 2014
407
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Table 8-4. GPIO Pad Configuration Examples (continued)
a
GPIO Register Bit Value
Configuration
DR2R
DR4R
DR8R
Digital Input/Output
(UART)
AFSEL
1
DIR
X
ODR
0
DEN
1
PUR
?
PDR
?
?
?
?
SLR
?
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 8-5. GPIO Interrupt Configuration Example
Desired Interrupt
Event Trigger
Register
GPIOIS
0=edge
a
Pin 2 Bit Value
7
6
5
4
3
2
1
0
X
X
X
X
X
0
X
X
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=level
GPIOIBE
0=single edge
1=both edges
GPIOIEV
0=Low level, or falling
edge
1=High level, or rising
edge
GPIOIM
0=masked
1=not masked
a. X=Ignored (don’t care bit)
8.4
Register Map
Table 8-7 on page 409 lists the GPIO registers. Each GPIO port can be accessed through one of
two bus apertures. The legacy aperture, the Advanced Peripheral Bus (APB), is backwards-compatible
with previous Stellaris parts. The other aperture, the Advanced High-Performance Bus (AHB), offers
the same register map but provides better back-to-back access performance than the APB bus.
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 unconnected bits has no effect, and reading unconnected bits returns
no meaningful data.
The offset listed is a hexadecimal increment to the register’s address, relative to that GPIO port’s
base address:
■
■
■
■
■
■
■
■
GPIO Port A (APB): 0x4000.4000
GPIO Port A (AHB): 0x4005.8000
GPIO Port B (APB): 0x4000.5000
GPIO Port B (AHB): 0x4005.9000
GPIO Port C (APB): 0x4000.6000
GPIO Port C (AHB): 0x4005.A000
GPIO Port D (APB): 0x4000.7000
GPIO Port D (AHB): 0x4005.B000
408
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
■
■
■
■
■
■
■
■
■
■
GPIO Port E (APB): 0x4002.4000
GPIO Port E (AHB): 0x4005.C000
GPIO Port F (APB): 0x4002.5000
GPIO Port F (AHB): 0x4005.D000
GPIO Port G (APB): 0x4002.6000
GPIO Port G (AHB): 0x4005.E000
GPIO Port H (APB): 0x4002.7000
GPIO Port H (AHB): 0x4005.F000
GPIO Port J (APB): 0x4003.D000
GPIO Port J (AHB): 0x4006.0000
Note that each GPIO module clock must be enabled before the registers can be programmed (see
page 288). There must be a delay of 3 system clocks after the GPIO module clock is enabled before
any GPIO module registers are accessed.
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 8-6. GPIO Pins With Non-Zero Reset Values
GPIO Pins
Default State
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR
GPIOPCTL
PA[1:0]
UART0
0
0
0
0
0x1
PA[5:2]
SSI0
0
0
0
0
0x1
PB[3:2]
I2C0
0
0
0
0
0x1
PC[3:0]
JTAG/SWD
1
1
0
1
0x3
The default register type for the GPIOCR register is RO for all GPIO pins with the exception of the
NMI pin and the four JTAG/SWD pins (PB7 and PC[3:0]). These five pins are 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 NMI pin and the four JTAG/SWD pins (PB7 and PC[3:0]). To ensure that the JTAG port is
not accidentally programmed as GPIO pins, the PC[3:0] pins default to non-committable. Similarly,
to ensure that the NMI pin is not accidentally programmed as a GPIO pin, the PB7 pin defaults to
non-committable. 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 8-7. GPIO Register Map
Description
See
page
Offset
Name
Type
Reset
0x000
GPIODATA
R/W
0x0000.0000
GPIO Data
411
0x400
GPIODIR
R/W
0x0000.0000
GPIO Direction
412
0x404
GPIOIS
R/W
0x0000.0000
GPIO Interrupt Sense
413
0x408
GPIOIBE
R/W
0x0000.0000
GPIO Interrupt Both Edges
414
0x40C
GPIOIEV
R/W
0x0000.0000
GPIO Interrupt Event
415
July 03, 2014
409
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Table 8-7. GPIO Register Map (continued)
Name
Type
Reset
0x410
GPIOIM
R/W
0x0000.0000
GPIO Interrupt Mask
416
0x414
GPIORIS
RO
0x0000.0000
GPIO Raw Interrupt Status
417
0x418
GPIOMIS
RO
0x0000.0000
GPIO Masked Interrupt Status
418
0x41C
GPIOICR
W1C
0x0000.0000
GPIO Interrupt Clear
420
0x420
GPIOAFSEL
R/W
-
GPIO Alternate Function Select
421
0x500
GPIODR2R
R/W
0x0000.00FF
GPIO 2-mA Drive Select
423
0x504
GPIODR4R
R/W
0x0000.0000
GPIO 4-mA Drive Select
424
0x508
GPIODR8R
R/W
0x0000.0000
GPIO 8-mA Drive Select
425
0x50C
GPIOODR
R/W
0x0000.0000
GPIO Open Drain Select
426
0x510
GPIOPUR
R/W
-
GPIO Pull-Up Select
427
0x514
GPIOPDR
R/W
0x0000.0000
GPIO Pull-Down Select
429
0x518
GPIOSLR
R/W
0x0000.0000
GPIO Slew Rate Control Select
431
0x51C
GPIODEN
R/W
-
GPIO Digital Enable
432
0x520
GPIOLOCK
R/W
0x0000.0001
GPIO Lock
434
0x524
GPIOCR
-
-
GPIO Commit
435
0x528
GPIOAMSEL
R/W
0x0000.0000
GPIO Analog Mode Select
437
0x52C
GPIOPCTL
R/W
-
GPIO Port Control
439
0xFD0
GPIOPeriphID4
RO
0x0000.0000
GPIO Peripheral Identification 4
441
0xFD4
GPIOPeriphID5
RO
0x0000.0000
GPIO Peripheral Identification 5
442
0xFD8
GPIOPeriphID6
RO
0x0000.0000
GPIO Peripheral Identification 6
443
0xFDC
GPIOPeriphID7
RO
0x0000.0000
GPIO Peripheral Identification 7
444
0xFE0
GPIOPeriphID0
RO
0x0000.0061
GPIO Peripheral Identification 0
445
0xFE4
GPIOPeriphID1
RO
0x0000.0000
GPIO Peripheral Identification 1
446
0xFE8
GPIOPeriphID2
RO
0x0000.0018
GPIO Peripheral Identification 2
447
0xFEC
GPIOPeriphID3
RO
0x0000.0001
GPIO Peripheral Identification 3
448
0xFF0
GPIOPCellID0
RO
0x0000.000D
GPIO PrimeCell Identification 0
449
0xFF4
GPIOPCellID1
RO
0x0000.00F0
GPIO PrimeCell Identification 1
450
0xFF8
GPIOPCellID2
RO
0x0000.0005
GPIO PrimeCell Identification 2
451
0xFFC
GPIOPCellID3
RO
0x0000.00B1
GPIO PrimeCell Identification 3
452
8.5
Description
See
page
Offset
Register Descriptions
The remainder of this section lists and describes the GPIO registers, in numerical order by address
offset.
410
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
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 412).
In order to write to GPIODATA, the corresponding bits in the mask, resulting from the address bus
bits [9:2], must be set. 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 set in the address mask cause
the corresponding bits in GPIODATA to be read, and bits that are clear 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
31:8
reserved
RO
0x0000.00
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.
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 written to the registers are
masked by the eight address lines [9:2]. Reads from this register return
its current state. Writes to this register only affect bits that are not masked
by ADDR[9:2] and are configured as outputs. See “Data Register
Operation” on page 405 for examples of reads and writes.
July 03, 2014
411
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 2: GPIO Direction (GPIODIR), offset 0x400
The GPIODIR register is the data direction register. Setting a bit in the GPIODIR register configures
the corresponding pin to be an output, while clearing a bit configures the corresponding pin to be
an input. All bits are cleared by a reset, meaning all GPIO pins are inputs by default.
GPIO Direction (GPIODIR)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
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
Value Description
0
Corresponding pin is an input.
1
Corresponding pins is an output.
412
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 3: GPIO Interrupt Sense (GPIOIS), offset 0x404
The GPIOIS register is the interrupt sense register. Setting a bit in the GPIOIS register configures
the corresponding pin to detect levels, while clearing a bit configures the corresponding pin to detect
edges. All bits are cleared by a reset.
GPIO Interrupt Sense (GPIOIS)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
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
Value Description
0
The edge on the corresponding pin is detected (edge-sensitive).
1
The level on the corresponding pin is detected (level-sensitive).
July 03, 2014
413
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 4: GPIO Interrupt Both Edges (GPIOIBE), offset 0x408
The GPIOIBE register allows both edges to cause interrupts. When the corresponding bit in the
GPIO Interrupt Sense (GPIOIS) register (see page 413) is set to detect edges, setting a bit in the
GPIOIBE register configures the corresponding pin to detect both rising and falling edges, regardless
of the corresponding bit in the GPIO Interrupt Event (GPIOIEV) register (see page 415). Clearing
a bit configures the pin to be controlled by the GPIOIEV register. All bits are cleared by a reset.
GPIO Interrupt Both Edges (GPIOIBE)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
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
Value Description
0
Interrupt generation is controlled by the GPIO Interrupt Event
(GPIOIEV) register (see page 415).
1
Both edges on the corresponding pin trigger an interrupt.
414
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 5: GPIO Interrupt Event (GPIOIEV), offset 0x40C
The GPIOIEV register is the interrupt event register. Setting a bit in the GPIOIEV register configures
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 413). Clearing a bit configures the
pin to detect falling edges or low levels, depending on the corresponding bit value in the GPIOIS
register. All bits are cleared by a reset.
GPIO Interrupt Event (GPIOIEV)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
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
Value Description
0
A falling edge or a Low level on the corresponding pin triggers
an interrupt.
1
A rising edge or a High level on the corresponding pin triggers
an interrupt.
July 03, 2014
415
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 6: GPIO Interrupt Mask (GPIOIM), offset 0x410
The GPIOIM register is the interrupt mask register. Setting a bit in the GPIOIM register allows
interrupts that are generated by the corresponding pin to be sent to the interrupt controller on the
combined interrupt signal. Clearing a bit prevents an interrupt on the corresponding pin from being
sent to the interrupt controller. All bits are cleared by a reset.
GPIO Interrupt Mask (GPIOIM)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
Value Description
0
The interrupt from the corresponding pin is masked.
1
The interrupt from the corresponding pin is sent to the interrupt
controller.
416
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 7: GPIO Raw Interrupt Status (GPIORIS), offset 0x414
The GPIORIS register is the raw interrupt status register. A bit in this register is set when an interrupt
condition occurs on the corresponding GPIO pin. If the corresponding bit in the GPIO Interrupt
Mask (GPIOIM) register (see page 416) is set, the interrupt is sent to the interrupt controller. Bits
read as zero indicate that corresponding input pins have not initiated an interrupt. A bit in this register
can be cleared by writing a 1 to the corresponding bit in the GPIO Interrupt Clear (GPIOICR)
register.
GPIO Raw Interrupt Status (GPIORIS)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
Value Description
1
An interrupt condition has occurred on the corresponding pin.
0
An interrupt condition has not occurred on the corresponding
pin.
A bit is cleared by writing a 1 to the corresponding bit in the GPIOICR
register.
July 03, 2014
417
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 8: GPIO Masked Interrupt Status (GPIOMIS), offset 0x418
The GPIOMIS register is the masked interrupt status register. If a bit is set in this register, the
corresponding interrupt has triggered an interrupt to the interrupt controller. If a bit is clear, 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 (the appropriate bit of GPIOIM is set), an interrupt
for Port B is generated, and 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. See page 631.
If no other Port B pins are being used to generate interrupts, the Interrupt 0-31 Set Enable (EN0)
register can disable the Port B interrupts, and the ADC interrupt can be used to read back the
converted data. Otherwise, the Port B interrupt handler must ignore and clear interrupts on PB4 and
wait for the ADC interrupt, or the ADC interrupt must be disabled in the EN0 register and the Port
B interrupt handler must poll the ADC registers until the conversion is completed. See page 133 for
more information.
GPIOMIS is the state of the interrupt after masking.
GPIO Masked Interrupt Status (GPIOMIS)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0x418
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
MIS
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0
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.
418
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Bit/Field
Name
Type
Reset
Description
7:0
MIS
RO
0x00
GPIO Masked Interrupt Status
Value Description
1
An interrupt condition on the corresponding pin has triggered
an interrupt to the interrupt controller.
0
An interrupt condition on the corresponding pin is masked or
has not occurred.
A bit is cleared by writing a 1 to the corresponding bit in the GPIOICR
register.
July 03, 2014
419
Texas Instruments-Production Data
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 bit in the GPIORIS and GPIOMIS registers. Writing a 0 has no effect.
GPIO Interrupt Clear (GPIOICR)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
Value Description
1
The corresponding interrupt is cleared.
0
The corresponding interrupt is unaffected.
420
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 10: GPIO Alternate Function Select (GPIOAFSEL), offset 0x420
The GPIOAFSEL register is the mode control select register. If a bit is clear, the pin is used as a
GPIO and is controlled by the GPIO registers. Setting a bit in this register configures the
corresponding GPIO line to be controlled by an associated peripheral. Several possible peripheral
functions are multiplexed on each GPIO. The GPIO Port Control (GPIOPCTL) register is used to
select one of the possible functions. Table 23-5 on page 1199 details which functions are muxed on
each GPIO pin. The reset value for this register is 0x0000.0000 for GPIO ports that are not listed
in the table below.
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 8-8. GPIO Pins With Non-Zero Reset Values
GPIO Pins
Default State
PA[1:0]
UART0
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR
0
0
0
0
GPIOPCTL
0x1
PA[5:2]
SSI0
0
0
0
0
0x1
PB[3:2]
I2C0
0
0
0
0
0x1
PC[3:0]
JTAG/SWD
1
1
0
1
0x3
Caution – 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. As a result, the debugger may be locked out of the part.
This issue can be avoided with a software routine that restores JTAG functionality based on an external
or software trigger.
The GPIO commit control registers provide a layer of protection against accidental programming of
critical hardware peripherals. Protection is provided for the NMI pin (PB7) and the four JTAG/SWD
pins (PC[3:0]). Writes to protected bits of the GPIO Alternate Function Select (GPIOAFSEL)
register (see page 421), GPIO Pull Up Select (GPIOPUR) register (see page 427), GPIO Pull-Down
Select (GPIOPDR) register (see page 429), and GPIO Digital Enable (GPIODEN) register (see
page 432) are not committed to storage unless the GPIO Lock (GPIOLOCK) register (see page 434)
has been unlocked and the appropriate bits of the GPIO Commit (GPIOCR) register (see page 435)
have been set.
When using the I2C module, in addition to setting the GPIOAFSEL register bits for the I2C clock
and data pins, the data pins should be set to open drain using the GPIO Open Drain Select
(GPIOODR) register (see examples in “Initialization and Configuration” on page 407).
July 03, 2014
421
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
GPIO Alternate Function Select (GPIOAFSEL)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0x420
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
AFSEL
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
AFSEL
R/W
-
RO
0
R/W
-
R/W
-
R/W
-
R/W
-
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 Alternate Function Select
Value Description
0
The associated pin functions as a GPIO and is controlled by
the GPIO registers.
1
The associated pin functions as a peripheral signal and is
controlled by the alternate hardware function.
The reset value for this register is 0x0000.0000 for GPIO ports
that are not listed in Table 8-1 on page 398.
422
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 11: GPIO 2-mA Drive Select (GPIODR2R), offset 0x500
The GPIODR2R register is the 2-mA drive control register. Each GPIO signal in the port can be
individually configured without affecting the other pads. When setting the DRV2 bit for a GPIO signal,
the corresponding DRV4 bit in the GPIODR4R register and DRV8 bit in the GPIODR8R register are
automatically cleared by hardware. By default, all GPIO pins have 2-mA drive.
GPIO 2-mA Drive Select (GPIODR2R)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
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
Value Description
1
The corresponding GPIO pin has 2-mA drive.
0
The drive for the corresponding GPIO pin is controlled by the
GPIODR4R or GPIODR8R register.
Setting a bit in either the GPIODR4 register or the GPIODR8 register
clears the corresponding 2-mA enable bit. The change is effective on
the second clock cycle after the write if accessing GPIO via the APB
memory aperture. If using AHB access, the change is effective on the
next clock cycle.
July 03, 2014
423
Texas Instruments-Production Data
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. Each GPIO signal in the port can be
individually configured without affecting the other pads. When setting the DRV4 bit for a GPIO signal,
the corresponding DRV2 bit in the GPIODR2R register and DRV8 bit in the GPIODR8R register are
automatically cleared by hardware.
GPIO 4-mA Drive Select (GPIODR4R)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
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
Value Description
1
The corresponding GPIO pin has 4-mA drive.
0
The drive for the corresponding GPIO pin is controlled by the
GPIODR2R or GPIODR8R register.
Setting a bit in either the GPIODR2 register or the GPIODR8 register
clears the corresponding 4-mA enable bit. The change is effective on
the second clock cycle after the write if accessing GPIO via the APB
memory aperture. If using AHB access, the change is effective on the
next clock cycle.
424
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 13: GPIO 8-mA Drive Select (GPIODR8R), offset 0x508
The GPIODR8R register is the 8-mA drive control register. Each GPIO signal in the port can be
individually configured without affecting the other pads. When setting the DRV8 bit for a GPIO signal,
the corresponding DRV2 bit in the GPIODR2R register and DRV4 bit in the GPIODR4R register are
automatically cleared by hardware. The 8-mA setting is also used for high-current operation.
Note:
There is no configuration difference between 8-mA and high-current operation. The additional
current capacity results from a shift in the VOH/VOL levels. See “Recommended Operating
Conditions” on page 1247 for further information.
GPIO 8-mA Drive Select (GPIODR8R)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
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
Value Description
1
The corresponding GPIO pin has 8-mA drive.
0
The drive for the corresponding GPIO pin is controlled by the
GPIODR2R or GPIODR4R register.
Setting a bit in either the GPIODR2 register or the GPIODR4 register
clears the corresponding 8-mA enable bit. The change is effective on
the second clock cycle after the write if accessing GPIO via the APB
memory aperture. If using AHB access, the change is effective on the
next clock cycle.
July 03, 2014
425
Texas Instruments-Production Data
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 Enable (GPIODEN) register (see page 432).
Corresponding bits in the drive strength and slew rate control registers (GPIODR2R, GPIODR4R,
GPIODR8R, and GPIOSLR) can be set to achieve the desired rise and fall times. The GPIO acts
as an input if the corresponding bit in the GPIODIR register is cleared. If open drain is selected while
the GPIO is configured as an input, the GPIO will remain an input and the open-drain selection has
no effect until the GPIO is changed to an output.
When using the I2C module, in addition to configuring the pin to open drain, the GPIO Alternate
Function Select (GPIOAFSEL) register bits for the I2C clock and data pins should be set (see
examples in “Initialization and Configuration” on page 407).
GPIO Open Drain Select (GPIOODR)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0x50C
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
ODE
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
ODE
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 Open Drain Enable
Value Description
1
The corresponding pin is configured as open drain.
0
The corresponding pin is not configured as open drain.
426
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 15: GPIO Pull-Up Select (GPIOPUR), offset 0x510
The GPIOPUR register is the pull-up control register. When a bit is set, a weak pull-up resistor on
the corresponding GPIO signal is enabled. Setting a bit in GPIOPUR automatically clears the
corresponding bit in the GPIO Pull-Down Select (GPIOPDR) register (see page 429). Write access
to this register is protected with the GPIOCR register. Bits in GPIOCR that are cleared prevent writes
to the equivalent bit in this register.
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 8-9. GPIO Pins With Non-Zero Reset Values
Note:
GPIO Pins
Default State
PA[1:0]
UART0
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR
0
0
0
GPIOPCTL
0
0x1
PA[5:2]
SSI0
0
0
0
0
0x1
PB[3:2]
I2C0
0
0
0
0
0x1
PC[3:0]
JTAG/SWD
1
1
0
1
0x3
The GPIO commit control registers provide a layer of protection against accidental
programming of critical hardware peripherals. Protection is provided for the NMI pin (PB7)
and the four JTAG/SWD pins (PC[3:0]). Writes to protected bits of the GPIO Alternate
Function Select (GPIOAFSEL) register (see page 421), GPIO Pull Up Select (GPIOPUR)
register (see page 427), GPIO Pull-Down Select (GPIOPDR) register (see page 429), and
GPIO Digital Enable (GPIODEN) register (see page 432) are not committed to storage
unless the GPIO Lock (GPIOLOCK) register (see page 434) has been unlocked and the
appropriate bits of the GPIO Commit (GPIOCR) register (see page 435) have been set.
GPIO Pull-Up Select (GPIOPUR)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0x510
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
RO
0
PUE
July 03, 2014
427
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PUE
R/W
-
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-Up Enable
Value Description
0
The corresponding pin's weak pull-up resistor is disabled.
1
The corresponding pin's weak pull-up resistor is enabled.
Setting a bit in the GPIOPDR register clears the corresponding bit in
the GPIOPUR register. The change is effective on the second clock
cycle after the write if accessing GPIO via the APB memory aperture.
If using AHB access, the change is effective on the next clock cycle.
The reset value for this register is 0x0000.0000 for GPIO ports that are
not listed in Table 8-1 on page 398.
428
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 16: GPIO Pull-Down Select (GPIOPDR), offset 0x514
The GPIOPDR register is the pull-down control register. When a bit is set, a weak pull-down resistor
on the corresponding GPIO signal is enabled. Setting a bit in GPIOPDR automatically clears the
corresponding bit in the GPIO Pull-Up Select (GPIOPUR) register (see page 427).
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 8-10. GPIO Pins With Non-Zero Reset Values
Note:
GPIO Pins
Default State
PA[1:0]
UART0
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR
0
0
0
GPIOPCTL
0
0x1
PA[5:2]
SSI0
0
0
0
0
0x1
PB[3:2]
I2C0
0
0
0
0
0x1
PC[3:0]
JTAG/SWD
1
1
0
1
0x3
The GPIO commit control registers provide a layer of protection against accidental
programming of critical hardware peripherals. Protection is provided for the NMI pin (PB7)
and the four JTAG/SWD pins (PC[3:0]). Writes to protected bits of the GPIO Alternate
Function Select (GPIOAFSEL) register (see page 421), GPIO Pull Up Select (GPIOPUR)
register (see page 427), GPIO Pull-Down Select (GPIOPDR) register (see page 429), and
GPIO Digital Enable (GPIODEN) register (see page 432) are not committed to storage
unless the GPIO Lock (GPIOLOCK) register (see page 434) has been unlocked and the
appropriate bits of the GPIO Commit (GPIOCR) register (see page 435) have been set.
GPIO Pull-Down Select (GPIOPDR)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0x514
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
RO
0
PDE
July 03, 2014
429
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PDE
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.
Pad Weak Pull-Down Enable
Value Description
0
The corresponding pin's weak pull-down resistor is disabled.
1
The corresponding pin's weak pull-down resistor is enabled.
Setting a bit in the GPIOPUR register clears the corresponding bit in
the GPIOPDR register. The change is effective on the second clock
cycle after the write if accessing GPIO via the APB memory aperture.
If using AHB access, the change is effective on the next clock cycle.
430
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 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 425).
GPIO Slew Rate Control Select (GPIOSLR)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
SRL
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.
Slew Rate Limit Enable (8-mA drive only)
Value Description
1
Slew rate control is enabled for the corresponding pin.
0
Slew rate control is disabled for the corresponding pin.
July 03, 2014
431
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 18: GPIO Digital Enable (GPIODEN), offset 0x51C
Note:
Pins configured as digital inputs are Schmitt-triggered.
The GPIODEN register is the digital enable register. By default, all GPIO signals except those listed
below 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 as a digital input or output (either GPIO or alternate function), the corresponding GPIODEN
bit must be set.
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 8-11. GPIO Pins With Non-Zero Reset Values
Note:
GPIO Pins
Default State
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR
GPIOPCTL
PA[1:0]
UART0
0
0
0
0
0x1
PA[5:2]
SSI0
0
0
0
0
0x1
PB[3:2]
I2C0
0
0
0
0
0x1
PC[3:0]
JTAG/SWD
1
1
0
1
0x3
The GPIO commit control registers provide a layer of protection against accidental
programming of critical hardware peripherals. Protection is provided for the NMI pin (PB7)
and the four JTAG/SWD pins (PC[3:0]). Writes to protected bits of the GPIO Alternate
Function Select (GPIOAFSEL) register (see page 421), GPIO Pull Up Select (GPIOPUR)
register (see page 427), GPIO Pull-Down Select (GPIOPDR) register (see page 429), and
GPIO Digital Enable (GPIODEN) register (see page 432) are not committed to storage
unless the GPIO Lock (GPIOLOCK) register (see page 434) has been unlocked and the
appropriate bits of the GPIO Commit (GPIOCR) register (see page 435) have been set.
432
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
GPIO Digital Enable (GPIODEN)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
DEN
R/W
-
RO
0
R/W
-
R/W
-
R/W
-
R/W
-
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Digital Enable
Value Description
0
The digital functions for the corresponding pin are disabled.
1
The digital functions for the corresponding pin are enabled.
The reset value for this register is 0x0000.0000 for GPIO ports
that are not listed in Table 8-1 on page 398.
July 03, 2014
433
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 19: GPIO Lock (GPIOLOCK), offset 0x520
The GPIOLOCK register enables write access to the GPIOCR register (see page 435). Writing
0x4C4F.434B to the GPIOLOCK register unlocks 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 0x0000.0001. When write accesses
are enabled, or unlocked, reading the GPIOLOCK register returns 0x0000.0000.
GPIO Lock (GPIOLOCK)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
R/W
0
Bit/Field
Name
Type
31:0
LOCK
R/W
R/W
0
Reset
R/W
0
Description
0x0000.0001 GPIO Lock
A write of the value 0x4C4F.434B unlocks the GPIO Commit (GPIOCR)
register for write access.A write of any other value or a write to the
GPIOCR register reapplies the lock, preventing any register updates.
A read of this register returns the following values:
Value Description
0x1
The GPIOCR register is locked and may not be modified.
0x0
The GPIOCR register is unlocked and may be modified.
434
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
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, GPIOPUR, GPIOPDR, and GPIODEN registers are committed when a
write to these registers is performed. If a bit in the GPIOCR register is cleared, the data being written
to the corresponding bit in the GPIOAFSEL, GPIOPUR, GPIOPDR, or GPIODEN registers cannot
be committed and retains its previous value. If a bit in the GPIOCR register is set, the data being
written to the corresponding bit of the GPIOAFSEL, GPIOPUR, GPIOPDR, or GPIODEN registers
is committed to the register and reflects the new value.
The contents of the GPIOCR register can only be modified if the status in the GPIOLOCK register
is unlocked. Writes to the GPIOCR register are ignored if the status in the GPIOLOCK register is
locked.
Important: This register is designed to prevent accidental programming of the registers that control
connectivity to the NMI and JTAG/SWD debug hardware. By initializing the bits of the
GPIOCR register to 0 for PB7 and PC[3:0], the NMI and JTAG/SWD debug port can
only be converted to GPIOs through a deliberate set of writes to the GPIOLOCK,
GPIOCR, and the corresponding registers.
Because this protection is currently only implemented on the NMI and 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, GPIOPUR, GPIOPDR, or GPIODEN register bits of
these other pins.
GPIO Commit (GPIOCR)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
RO
0
CR
July 03, 2014
435
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
CR
-
-
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 Commit
Value Description
1
The corresponding GPIOAFSEL, GPIOPUR, GPIOPDR, or
GPIODEN bits can be written.
0
The corresponding GPIOAFSEL, GPIOPUR, GPIOPDR, or
GPIODEN bits cannot be written.
Note:
The default register type for the GPIOCR register is RO for
all GPIO pins with the exception of the NMI pin and the four
JTAG/SWD pins (PB7 and PC[3:0]). These five pins are 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 NMI
pin and the four JTAG/SWD pins (PB7 and PC[3:0]). To
ensure that the JTAG port is not accidentally programmed as
GPIO pins, the PC[3:0] pins default to non-committable.
Similarly, to ensure that the NMI pin is not accidentally
programmed as a GPIO pin, the PB7 pin defaults to
non-committable. 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.
436
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 21: GPIO Analog Mode Select (GPIOAMSEL), offset 0x528
Important: This register is only valid for ports D and E; the corresponding base addresses for the
remaining ports are not valid.
If any pin is to be used as an ADC input, the appropriate bit in GPIOAMSEL must be
set to disable the analog isolation circuit.
The GPIOAMSEL register controls isolation circuits to the analog side of a unified I/O pad. Because
the GPIOs may be driven by a 5-V source and affect analog operation, analog circuitry requires
isolation from the pins when they are not used in their analog function.
Each bit of this register controls the isolation circuitry for the corresponding GPIO signal. For
information on which GPIO pins can be used for ADC functions, refer to Table 23-5 on page 1199.
GPIO Analog Mode Select (GPIOAMSEL)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0x528
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
GPIOAMSEL
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
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.
July 03, 2014
437
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Bit/Field
Name
Type
Reset
Description
7:0
GPIOAMSEL
R/W
0x00
GPIO Analog Mode Select
Value Description
1
The analog function of the pin is enabled, the isolation is
disabled, and the pin is capable of analog functions.
0
The analog function of the pin is disabled, the isolation is
enabled, and the pin is capable of digital functions as specified
by the other GPIO configuration registers.
Note:
This register and bits are only valid for GPIO signals that
share analog function through a unified I/O pad.
The reset state of this register is 0 for all signals.
438
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 22: GPIO Port Control (GPIOPCTL), offset 0x52C
The GPIOPCTL register is used in conjunction with the GPIOAFSEL register and selects the specific
peripheral signal for each GPIO pin when using the alternate function mode. Most bits in the
GPIOAFSEL register are cleared on reset, therefore most GPIO pins are configured as GPIOs by
default. When a bit is set in the GPIOAFSEL register, the corresponding GPIO signal is controlled
by an associated peripheral. The GPIOPCTL register selects one out of a set of peripheral functions
for each GPIO, providing additional flexibility in signal definition. For information on the defined
encodings for the bit fields in this register, refer to Table 23-5 on page 1199. The reset value for this
register is 0x0000.0000 for GPIO ports that are not listed in the table below.
Note:
If the same signal is assigned to two different GPIO port pins, the signal is assigned to the
port with the lowest letter and the assignment to the higher letter port is ignored.
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 8-12. GPIO Pins With Non-Zero Reset Values
GPIO Pins
Default State
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR
GPIOPCTL
PA[1:0]
UART0
0
0
0
0
0x1
PA[5:2]
SSI0
0
0
0
0
0x1
PB[3:2]
I2C0
0
0
0
0
0x1
PC[3:0]
JTAG/SWD
1
1
0
1
0x3
GPIO Port Control (GPIOPCTL)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0x52C
Type R/W, reset 31
30
29
28
27
26
R/W
-
25
24
23
22
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
15
14
13
12
11
10
9
8
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
PMC7
Type
Reset
20
19
18
R/W
-
R/W
-
R/W
-
R/W
-
7
6
5
4
R/W
-
R/W
-
R/W
-
R/W
-
PMC6
PMC3
Type
Reset
21
17
16
R/W
-
R/W
-
R/W
-
3
2
1
0
R/W
-
R/W
-
R/W
-
R/W
-
PMC5
PMC2
PMC4
PMC1
PMC0
July 03, 2014
439
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Bit/Field
Name
Type
Reset
31:28
PMC7
R/W
-
Description
Port Mux Control 7
This field controls the configuration for GPIO pin 7.
27:24
PMC6
R/W
-
Port Mux Control 6
This field controls the configuration for GPIO pin 6.
23:20
PMC5
R/W
-
Port Mux Control 5
This field controls the configuration for GPIO pin 5.
19:16
PMC4
R/W
-
Port Mux Control 4
This field controls the configuration for GPIO pin 4.
15:12
PMC3
R/W
-
Port Mux Control 3
This field controls the configuration for GPIO pin 3.
11:8
PMC2
R/W
-
Port Mux Control 2
This field controls the configuration for GPIO pin 2.
7:4
PMC1
R/W
-
Port Mux Control 1
This field controls the configuration for GPIO pin 1.
3:0
PMC0
R/W
-
Port Mux Control 0
This field controls the configuration for GPIO pin 0.
440
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 23: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0xFD0
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID4
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PID4
RO
0x00
RO
0
RO
0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO Peripheral ID Register [7:0]
July 03, 2014
441
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 24: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
7:0
PID5
RO
0x00
RO
0
RO
0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO Peripheral ID Register [15:8]
442
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 25: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
7:0
PID6
RO
0x00
RO
0
RO
0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO Peripheral ID Register [23:16]
July 03, 2014
443
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 26: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
7:0
PID7
RO
0x00
RO
0
RO
0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO Peripheral ID Register [31:24]
444
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 27: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0xFE0
Type RO, reset 0x0000.0061
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
0x0000.00
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.
July 03, 2014
445
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 28: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0xFE4
Type RO, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
PID1
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
PID1
RO
0x00
RO
0
RO
0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO Peripheral ID Register [15:8]
Can be used by software to identify the presence of this peripheral.
446
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 29: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
7:0
PID2
RO
0x18
RO
0
RO
0
RO
0
RO
0
RO
1
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO Peripheral ID Register [23:16]
Can be used by software to identify the presence of this peripheral.
July 03, 2014
447
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 30: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
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
0x0000.00
7:0
PID3
RO
0x01
RO
0
RO
0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO Peripheral ID Register [31:24]
Can be used by software to identify the presence of this peripheral.
448
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 31: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0xFF0
Type RO, reset 0x0000.000D
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
1
RO
1
RO
0
RO
1
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CID0
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
CID0
RO
0x0D
RO
0
RO
0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO PrimeCell ID Register [7:0]
Provides software a standard cross-peripheral identification system.
July 03, 2014
449
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 32: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0xFF4
Type RO, reset 0x0000.00F0
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
0
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CID1
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
CID1
RO
0xF0
RO
0
RO
1
RO
1
RO
1
RO
1
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO PrimeCell ID Register [15:8]
Provides software a standard cross-peripheral identification system.
450
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Register 33: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0xFF8
Type RO, reset 0x0000.0005
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
1
RO
0
RO
1
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CID2
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
CID2
RO
0x05
RO
0
RO
0
RO
0
RO
0
RO
0
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO PrimeCell ID Register [23:16]
Provides software a standard cross-peripheral identification system.
July 03, 2014
451
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
Register 34: 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 (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (APB) base: 0x4002.5000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (APB) base: 0x4002.6000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (APB) base: 0x4002.7000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (APB) base: 0x4003.D000
GPIO Port J (AHB) base: 0x4006.0000
Offset 0xFFC
Type RO, reset 0x0000.00B1
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RO
0
RO
0
RO
0
RO
0
3
2
1
0
RO
0
RO
0
RO
0
RO
1
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
RO
0
15
14
13
12
11
10
9
8
7
6
5
4
reserved
Type
Reset
RO
0
RO
0
RO
0
RO
0
CID3
RO
0
RO
0
RO
0
Bit/Field
Name
Type
Reset
31:8
reserved
RO
0x0000.00
7:0
CID3
RO
0xB1
RO
0
RO
1
RO
0
RO
1
RO
1
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
GPIO PrimeCell ID Register [31:24]
Provides software a standard cross-peripheral identification system.
452
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
9
External Peripheral Interface (EPI)
The External Peripheral Interface is a high-speed parallel bus for external peripherals or memory.
It has several modes of operation to interface gluelessly to many types of external devices. The
External Peripheral Interface is similar to a standard microprocessor address/data bus, except that
it must typically be connected to just one type of external device. Enhanced capabilities include
µDMA support, clocking control and support for external FIFO buffers.
The EPI has the following features:
■ 8/16/32-bit dedicated parallel bus for external peripherals and memory
■ Memory interface supports contiguous memory access independent of data bus width, thus
enabling code execution directly from SDRAM, SRAM and Flash memory
■ Blocking and non-blocking reads
■ Separates processor from timing details through use of an internal write FIFO
■ Efficient transfers using Micro Direct Memory Access Controller (µDMA)
– Separate channels for read and write
– Read channel request asserted by programmable levels on the internal non-blocking read
FIFO (NBRFIFO)
– Write channel request asserted by empty on the internal write FIFO (WFIFO)
The EPI supports three primary functional modes: Synchronous Dynamic Random Access Memory
(SDRAM) mode, Traditional Host-Bus mode, and General-Purpose mode. The EPI module also
provides custom GPIOs; however, unlike regular GPIOs, the EPI module uses a FIFO in the same
way as a communication mechanism and is speed-controlled using clocking.
■ Synchronous Dynamic Random Access Memory (SDRAM) mode
– Supports x16 (single data rate) SDRAM at up to 50 MHz
– Supports low-cost SDRAMs up to 64 MB (512 megabits)
– Includes automatic refresh and access to all banks/rows
– Includes a Sleep/Standby mode to keep contents active with minimal power draw
– Multiplexed address/data interface for reduced pin count
■ Host-Bus mode
– Traditional x8 and x16 MCU bus interface capabilities
– Similar device compatibility options as PIC, ATmega, 8051, and others
– Access to SRAM, NOR Flash memory, and other devices, with up to 1 MB of addressing in
unmultiplexed mode and 256 MB in multiplexed mode (512 MB in Host-Bus 16 mode with
no byte selects)
July 03, 2014
453
Texas Instruments-Production Data
External Peripheral Interface (EPI)
– Support of both muxed and de-muxed address and data
– Access to a range of devices supporting the non-address FIFO x8 and x16 interface variant,
with support for external FIFO (XFIFO) EMPTY and FULL signals
– Speed controlled, with read and write data wait-state counters
– Chip select modes include ALE, CSn, Dual CSn and ALE with dual CSn
– Manual chip-enable (or use extra address pins)
■ General-Purpose mode
– Wide parallel interfaces for fast communications with CPLDs and FPGAs
– Data widths up to 32 bits
– Data rates up to 150 MB/second
– Optional "address" sizes from 4 bits to 20 bits
– Optional clock output, read/write strobes, framing (with counter-based size), and clock-enable
input
■ General parallel GPIO
– 1 to 32 bits, FIFOed with speed control
– Useful for custom peripherals or for digital data acquisition and actuator controls
9.1
EPI Block Diagram
®
Figure 9-1 on page 455 provides a block diagram of a Stellaris EPI module.
454
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Figure 9-1. EPI Block Diagram
General
Parallel
GPIO
NBRFIFO
8 x 32 bits
WFIFO
SDRAM
4 x 32 bits
AHB
Bus
Interface
With
DMA
AHB
EPI 31:0
Host Bus
Baud
Rate
Control
(Clock)
Wide
Parallel
Interface
9.2
Signal Description
The following table lists the external signals of the EPI controller and describes the function of each.
The EPI controller signals are alternate functions for GPIO signals and default to be GPIO signals
at reset. The column in the table below titled "Pin Mux/Pin Assignment" lists the GPIO pin placement
for the EPI signals. The AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register
(page 421) should be set to choose the EPI controller function. The number in parentheses is the
encoding that must be programmed into the PMCn field in the GPIO Port Control (GPIOPCTL)
register (page 439) to assign the EPI signals to the specified GPIO port pins. For more information
on configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 397.
Table 9-1. External Peripheral Interface Signals (100LQFP)
Pin Name
Pin Number Pin Mux / Pin
Assignment
Pin Type
a
Buffer Type
Description
EPI0S0
83
PH3 (8)
I/O
TTL
EPI module 0 signal 0.
EPI0S1
84
PH2 (8)
I/O
TTL
EPI module 0 signal 1.
EPI0S2
25
PC4 (8)
I/O
TTL
EPI module 0 signal 2.
EPI0S3
24
PC5 (8)
I/O
TTL
EPI module 0 signal 3.
EPI0S4
23
PC6 (8)
I/O
TTL
EPI module 0 signal 4.
EPI0S5
22
PC7 (8)
I/O
TTL
EPI module 0 signal 5.
EPI0S6
86
PH0 (8)
I/O
TTL
EPI module 0 signal 6.
EPI0S7
85
PH1 (8)
I/O
TTL
EPI module 0 signal 7.
EPI0S8
74
PE0 (8)
I/O
TTL
EPI module 0 signal 8.
EPI0S9
75
PE1 (8)
I/O
TTL
EPI module 0 signal 9.
EPI0S10
76
PH4 (8)
I/O
TTL
EPI module 0 signal 10.
July 03, 2014
455
Texas Instruments-Production Data
External Peripheral Interface (EPI)
Table 9-1. External Peripheral Interface Signals (100LQFP) (continued)
Pin Name
Pin Number Pin Mux / Pin
Assignment
a
Pin Type
Buffer Type
Description
EPI0S11
63
PH5 (8)
I/O
TTL
EPI module 0 signal 11.
EPI0S12
42
58
PF7 (8)
PF4 (8)
I/O
TTL
EPI module 0 signal 12.
EPI0S13
19
PG0 (8)
I/O
TTL
EPI module 0 signal 13.
EPI0S14
18
PG1 (8)
I/O
TTL
EPI module 0 signal 14.
EPI0S15
41
46
PG4 (8)
PF5 (8)
I/O
TTL
EPI module 0 signal 15.
EPI0S16
14
PJ0 (8)
I/O
TTL
EPI module 0 signal 16.
EPI0S17
87
PJ1 (8)
I/O
TTL
EPI module 0 signal 17.
EPI0S18
39
PJ2 (8)
I/O
TTL
EPI module 0 signal 18.
EPI0S19
50
97
PJ3 (8)
PD4 (10)
I/O
TTL
EPI module 0 signal 19.
EPI0S20
12
PD2 (8)
I/O
TTL
EPI module 0 signal 20.
EPI0S21
13
PD3 (8)
I/O
TTL
EPI module 0 signal 21.
EPI0S22
91
PB5 (8)
I/O
TTL
EPI module 0 signal 22.
EPI0S23
92
PB4 (8)
I/O
TTL
EPI module 0 signal 23.
EPI0S24
95
PE2 (8)
I/O
TTL
EPI module 0 signal 24.
EPI0S25
96
PE3 (8)
I/O
TTL
EPI module 0 signal 25.
EPI0S26
62
PH6 (8)
I/O
TTL
EPI module 0 signal 26.
EPI0S27
15
PH7 (8)
I/O
TTL
EPI module 0 signal 27.
EPI0S28
52
98
PJ4 (8)
PD5 (10)
I/O
TTL
EPI module 0 signal 28.
EPI0S29
53
99
PJ5 (8)
PD6 (10)
I/O
TTL
EPI module 0 signal 29.
EPI0S30
54
100
PJ6 (8)
PD7 (10)
I/O
TTL
EPI module 0 signal 30.
EPI0S31
36
PG7 (9)
I/O
TTL
EPI module 0 signal 31.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
Table 9-2. External Peripheral Interface Signals (108BGA)
Pin Name
Pin Number Pin Mux / Pin
Assignment
PH3 (8)
a
Pin Type
Buffer Type
I/O
TTL
Description
EPI0S0
D10
EPI module 0 signal 0.
EPI0S1
D11
PH2 (8)
I/O
TTL
EPI module 0 signal 1.
EPI0S2
L1
PC4 (8)
I/O
TTL
EPI module 0 signal 2.
EPI0S3
M1
PC5 (8)
I/O
TTL
EPI module 0 signal 3.
EPI0S4
M2
PC6 (8)
I/O
TTL
EPI module 0 signal 4.
EPI0S5
L2
PC7 (8)
I/O
TTL
EPI module 0 signal 5.
EPI0S6
C9
PH0 (8)
I/O
TTL
EPI module 0 signal 6.
EPI0S7
C8
PH1 (8)
I/O
TTL
EPI module 0 signal 7.
EPI0S8
B11
PE0 (8)
I/O
TTL
EPI module 0 signal 8.
EPI0S9
A12
PE1 (8)
I/O
TTL
EPI module 0 signal 9.
EPI0S10
B10
PH4 (8)
I/O
TTL
EPI module 0 signal 10.
456
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
Table 9-2. External Peripheral Interface Signals (108BGA) (continued)
Pin Name
Pin Number Pin Mux / Pin
Assignment
a
Pin Type
Buffer Type
Description
EPI0S11
F10
PH5 (8)
I/O
TTL
EPI module 0 signal 11.
EPI0S12
K4
L9
PF7 (8)
PF4 (8)
I/O
TTL
EPI module 0 signal 12.
EPI0S13
K1
PG0 (8)
I/O
TTL
EPI module 0 signal 13.
EPI0S14
K2
PG1 (8)
I/O
TTL
EPI module 0 signal 14.
EPI0S15
K3
L8
PG4 (8)
PF5 (8)
I/O
TTL
EPI module 0 signal 15.
EPI0S16
F3
PJ0 (8)
I/O
TTL
EPI module 0 signal 16.
EPI0S17
B6
PJ1 (8)
I/O
TTL
EPI module 0 signal 17.
EPI0S18
K6
PJ2 (8)
I/O
TTL
EPI module 0 signal 18.
EPI0S19
M10
B5
PJ3 (8)
PD4 (10)
I/O
TTL
EPI module 0 signal 19.
EPI0S20
H2
PD2 (8)
I/O
TTL
EPI module 0 signal 20.
EPI0S21
H1
PD3 (8)
I/O
TTL
EPI module 0 signal 21.
EPI0S22
B7
PB5 (8)
I/O
TTL
EPI module 0 signal 22.
EPI0S23
A6
PB4 (8)
I/O
TTL
EPI module 0 signal 23.
EPI0S24
A4
PE2 (8)
I/O
TTL
EPI module 0 signal 24.
EPI0S25
B4
PE3 (8)
I/O
TTL
EPI module 0 signal 25.
EPI0S26
G3
PH6 (8)
I/O
TTL
EPI module 0 signal 26.
EPI0S27
H3
PH7 (8)
I/O
TTL
EPI module 0 signal 27.
EPI0S28
K11
C6
PJ4 (8)
PD5 (10)
I/O
TTL
EPI module 0 signal 28.
EPI0S29
K12
A3
PJ5 (8)
PD6 (10)
I/O
TTL
EPI module 0 signal 29.
EPI0S30
L10
A2
PJ6 (8)
PD7 (10)
I/O
TTL
EPI module 0 signal 30.
EPI0S31
C10
PG7 (9)
I/O
TTL
EPI module 0 signal 31.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
9.3
Functional Description
The EPI controller provides a glueless, programmable interface to a variety of common external
peripherals such as SDRAM x 16, Host Bus x8 and x16 devices, RAM, NOR Flash memory, CPLDs
and FPGAs. In addition, the EPI controller provides custom GPIO that can use a FIFO with speed
control by using either the internal write FIFO (WFIFO) or the non-blocking read FIFO (NBRFIFO).
The WFIFO can hold 4 words of data that are written to the external interface at the rate controlled
by the EPI Main Baud Rate (EPIBAUD) register. The NBRFIFO can hold 8 words of data and
samples at the rate controlled by the EPIBAUD register. The EPI controller provides predictable
operation and thus has an advantage over regular GPIO which has more variable timing due to
on-chip bus arbitration and delays across bus bridges. Blocking reads stall the CPU until the
transaction completes. Non-blocking reads are performed in the background and allow the processor
to continue operation. In addition, write data can also be stored in the WFIFO to allow multiple writes
with no stalls.
July 03, 2014
457
Texas Instruments-Production Data
External Peripheral Interface (EPI)
Note:
Both the WTAV bit field in the EPIWFIFOCNT register and the WBUSY bit in the EPISTAT
register must be polled to determine if there is a current write transaction from the WFIFO.
If both of these bits are clear, then a new bus access may begin.
Main read and write operations can be performed in subsets of the range 0x6000.0000 to
0xDFFF.FFFF. A read from an address mapped location uses the offset and size to control the
address and size of the external operation. When performing a multi-value load, the read is done
as a burst (when available) to maximize performance. A write to an address mapped location uses
the offset and size to control the address and size of the external operation. When performing a
multi-value store, the write is done as a burst (when available) to maximize performance.
NAND Flash memory (x8) can be read natively. Automatic programming support is not provided;
programming must be done by the user following the manufacturer's protocol. Automatic page ECC
is also not supported, but can be performed in software.
9.3.1
Non-Blocking Reads
The EPI Controller supports a special kind of read called a non-blocking read, also referred to as a
posted read. Where a normal read stalls the processor or μDMA until the data is returned, a
non-blocking read is performed in the background.
A non-blocking read is configured by writing the start address into a EPIRADDRn register, the size
per transaction into a EPIRSIZEn register, and then the count of operations into a EPIRPSTDn
register. After each read is completed, the result is written into the NBRFIFO and the EPIRADDRn
register is incremented by the size (1, 2, or 4).
If the NBRFIFO is filled, then the reads pause until space is made available. The NBRFIFO can be
configured to interrupt the processor or trigger the μDMA based on fullness using the EPIFIFOLVL
register. By using the trigger/interrupt method, the μDMA (or processor) can keep space available
in the NBRFIFO and allow the reads to continue unimpeded.
When performing non-blocking reads, the SDRAM controller issues two additional read transactions
after the burst request is terminated. The data for these additional transfers is discarded. This
situation is transparent to the user other than the additional EPI bus activity and can safely be
ignored.
Two non-blocking read register sets are available to allow sequencing and ping-pong use. When
one completes, the other then activates. So, for example, if 20 words are to be read from 0x100
and 10 words from 0x200, the EPIRPSTD0 register can be set up with the read from 0x100 (with a
count of 20), and the EPIRPSTD1 register can be set up with the read from 0x200 (with a count of
10). When EPIRPSTD0 finishes (count goes to 0), the EPIRPSTD1 register then starts its operation.
The NBRFIFO has then passed 30 values. When used with the μDMA, it may transfer 30 values
(simple sequence), or the primary/alternate model may be used to handle the first 20 in one way
and the second 10 in another. It is also possible to reload the EPIRPSTD0 register when it is finished
(and the EPIRPSTD1 register is active); thereby, keeping the interface constantly busy.
To cancel a non-blocking read, the EPIRPSTDn register is cleared. Care must be taken, however
if the register set was active to drain away any values read into the NBRFIFO and ensure that any
read in progress is allowed to complete.
To ensure that the cancel is complete, the following algorithm is used (using the EPIRPSTD0 register
for example):
EPIRPSTD0 = 0;
while ((EPISTAT & 0x11) == 0x10)
; // we are active and busy
458
July 03, 2014
Texas Instruments-Production Data
®
Stellaris LM3S5791 Microcontroller
// if here, then other one is active or interface no longer busy
cnt = (EPIRADDR0 – original_address) / EPIRSIZE0; // count of values read
cnt -= values_read_so_far;
// cnt is now number left in FIFO
while (cnt--)
value = EPIREADFIFO; // drain
The above algorithm can be optimized in code; however, the important point is to wait for the cancel
to complete because the external interface could have been in the process of reading a value when
the cancel came in, and it must be allowed to complete.
9.3.2
DMA Operation
The µDMA can be used to achieve maximum transfer rates on the EPI through the NBRFIFO and
the WFIFO. The µDMA has one channel for write and one for read. The write channel copies values
to the WFIFO when the WFIFO is at the level specified by the EPI FIFO Level Selects (EPIFIFOLVL)
register. The non-blocking read channel copies values from the NBRFIFO when the NBRFIFO is
at the level specified by the EPIFIFOLVL register. For non-blocking reads, the start address, the
size per transaction, and the count of elements must be programmed in the µDMA. Note that both
non-blocking read register sets can be used, and they fill the NBRFIFO such that one runs to
completion, then the next one starts (they do not interleave). Using the NBRFIFO provides the best
possible transfer rate.
For blocking reads, the µDMA software channel (or another unused channel) is used for
memory-to-memory transfers (or memory to peripheral, where some other peripheral is used). In
this situation, the µDMA stalls until the read is complete and is not able to service another channel
until the read is done. As a result, the arbitration size should normally be programmed to one access
at a time. The µDMA controller can also transfer from and to the NBRFIFO and the WFIFO using
the µDMA software channel in memory mode, however, the µDMA is stalled once the NBRFIFO is
empty or the WFIFO is full. Note that when the µDMA controller is stalled, the core continues
operation. See “Micro Direct Memory Access (μDMA)” on page 338 for more information on configuring
the µDMA.
The size of the FIFOs must be taken into consideration when configuring the µDMA to transfer data
to and from the EPI. The arbitration size should be 4 or less when writing to EPI address space and
8 or less when reading from EPI address space.
9.4
Initialization and Configuration
T