Stellaris Peripheral Driver Library User's Guide

Stellaris® Peripheral Driver Library

USER’S GUIDE

PDL-LM3S-uvision-UG-1716 Copyright © 2006-2007 Luminary Micro, Inc.

2

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LibraryS.

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Revision Information

This is version 1716 of this document, last updated on October 11, 2007.

October 11, 2007

Stellaris Peripheral Driver Library User’s Guide

Table of Contents

Legal Disclaimers and Trademark Information

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

Revision Information

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

5

2 Analog Comparator

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.1

Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2

API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

2.3

Programming Example

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13

7

7

3 Analog to Digital Converter

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15

3.1

Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15

3.2

API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15

3.3

Programming Example

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27

4 Controller Area Network (CAN)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29

4.1

Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29

4.2

API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29

4.3

Programming Example

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

49

5 Ethernet Controller

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

51

5.1

Introduction

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51

5.2

API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

51

5.3

Programming Example

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

63

6 Flash

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65

6.1

Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65

6.2

API Functions

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65

6.3

Programming Example

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

73

7 GPIO

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

75

7.1

Introduction

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75

7.2

API Functions

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75

7.3

Programming Example

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

90

8 Hibernation Module

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

93

8.1

Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

93

8.2

API Functions

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93

8.3

Programming Example

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9 I2C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

9.1

Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

9.2

API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

9.3

Programming Example

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

10 Interrupt Controller

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

10.3 Programming Example

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

11 Pulse Width Modulator

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

11.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

11.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

12 Quadrature Encoder

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

12.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

October 11, 2007 3

Table of Contents

12.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

13 Synchronous Serial Interface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

13.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

13.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

14 System Control

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

14.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

14.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

15 SysTick

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

15.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

15.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

16 Timer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

16.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

16.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

17 UART

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

17.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

17.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

18 Watchdog Timer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

18.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

18.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

19 Error Handling

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

20 DK-LM3S101 Example Applications

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

20.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

20.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

20.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

21.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

21.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

21.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

22.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

22.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

22.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

23.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

23.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

23.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

24.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

24.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

24.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

4 October 11, 2007


25.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

25.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

25.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

26.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

26.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

26.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

27.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

27.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

27.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

28.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

28.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

28.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

29 EK-LM3S1968 Example Applications

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

29.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

29.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

29.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

30.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

30.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

30.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

31.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

31.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

31.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

32 EK-LM3S6965 Rev C Example Applications

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359

32.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359

32.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359

32.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

33.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

33.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

33.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375

34.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375

34.2 API Functions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375

34.3 Examples

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

Company Information

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384

Support Information

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384

October 11, 2007 5

Table of Contents

6 October 11, 2007

1


Introduction

The Stellaris Peripheral Driver Library is a set of drivers for accessing the peripherals found on the

Stellaris family of ARM® Cortex™-M3 based microcontrollers. While they are not drivers in the pure operating system sense (i.e. they do not have a common interface and do not connect into a global device driver infrastructure), they do provide a mechanism that makes it easy to use the device’s peripherals.

The capabilities and organization of the drivers are governed by the following design goals:

They are written entirely in C except where absolutely not possible.

They demonstrate how to use the peripheral in its common mode of operation.

They are easy to understand.

They are reasonably efficient in terms of memory and processor usage.

They are as self-contained as possible.

Where possible, computations that can be performed at compile time are done there instead of at run time.

Some consequences of these design goals are:

The drivers are not necessarily as efficient as they could be (from a code size and/or execution speed point of view). While the most efficient piece of code for operating a peripheral would be written in assembly and custom tailored to the specific requirements of the application, further size optimizations of the drivers would make them more difficult to understand.

The drivers do not support the full capabilities of the hardware. Some of the peripherals provide complex capabilities which can not be utilized by the drivers in this library, though the existing code can be used as a reference upon which to add support for the additional capabilities.

The APIs have a means of removing all error checking code. Since the error checking is usually only useful during initial program development, it can be removed to improve code size and speed.

For many applications, the drivers can be used as is. But in some cases, the drivers will have to be enhanced or rewritten in order to meet the functionality, memory, or processing requirements of the application. If so, the existing driver can be used as a reference on how to operate the peripheral.

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Introduction

8 October 11, 2007

2


Analog Comparator

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Programming Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.1

Introduction

The comparator API provides a set of functions for dealing with the analog comparators. A comparator can compare a test voltage against individual external reference voltage, a shared single external reference voltage, or a shared internal reference voltage. It 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, so that an interrupt can be generated on a rising edge and the ADC triggered on a falling edge (for example).

2.2

API Functions

Functions void

ComparatorConfigure

(unsigned long ulBase, unsigned long ulComp, unsigned long ul-

Config) void

ComparatorIntClear

(unsigned long ulBase, unsigned long ulComp) void

ComparatorIntDisable


ComparatorIntEnable


ComparatorIntRegister

(unsigned long ulBase, unsigned long ulComp, void (∗pfn-

Handler)(void)) tBoolean

ComparatorIntStatus

(unsigned long ulBase, unsigned long ulComp, tBoolean b-

Masked) void

ComparatorIntUnregister


ComparatorRefSet

(unsigned long ulBase, unsigned long ulRef) tBoolean

ComparatorValueGet

(unsigned long ulBase, unsigned long ulComp)

2.2.1

Detailed Description

The comparator API is fairly simple, like the comparators themselves. There are functions for

configuring a comparator and reading its output ( ComparatorConfigure() ,

ComparatorRefSet()

and

ComparatorValueGet() ) and functions for dealing with an interrupt handler for the compara-

tor ( ComparatorIntRegister() ,

ComparatorIntUnregister() ,

ComparatorIntEnable() , ComparatorInt-

Disable() ,

ComparatorIntStatus() , and

ComparatorIntClear() ).

October 11, 2007 9

Analog Comparator

2.2.2

Function Documentation

2.2.2.1

ComparatorConfigure

Configures a comparator.

Prototype:

void

ComparatorConfigure(unsigned long ulBase, unsigned long ulComp, unsigned long ulConfig)

Parameters:

ulBase is the base address of the comparator module.

ulComp is the index of the comparator to configure.

ulConfig is the configuration of the comparator.

Description:

This function will configure a comparator. The ulConfig parameter is the result of a logical

OR operation between the

COMP_TRIG_xxx, COMP_INT_xxx, COMP_ASRCP_xxx, and

COMP_OUTPUT_xxx values.

The COMP_TRIG_xxx term can take on the following values:

COMP_TRIG_NONE to have no trigger to the ADC.

COMP_TRIG_HIGH to trigger the ADC when the comparator output is high.

COMP_TRIG_LOW to trigger the ADC when the comparator output is low.

COMP_TRIG_FALL to trigger the ADC when the comparator output goes low.

COMP_TRIG_RISE to trigger the ADC when the comparator output goes high.

COMP_TRIG_BOTH to trigger the ADC when the comparator output goes low or high.

The COMP_INT_xxx term can take on the following values:

COMP_INT_HIGH to generate an interrupt when the comparator output is high.

COMP_INT_LOW to generate an interrupt when the comparator output is low.

COMP_INT_FALL to generate an interrupt when the comparator output goes low.

COMP_INT_RISE to generate an interrupt when the comparator output goes high.

COMP_INT_BOTH to generate an interrupt when the comparator output goes low or high.

The COMP_ASRCP_xxx term can take on the following values:

COMP_ASRCP_PIN to use the dedicated Comp+ pin as the reference voltage.

COMP_ASRCP_PIN0 to use the Comp0+ pin as the reference voltage (this the same as

COMP_ASRCP_PIN for the comparator 0).

COMP_ASRCP_REF to use the internally generated voltage as the reference voltage.

The COMP_OUTPUT_xxx term can take on the following values:

COMP_OUTPUT_NORMAL to enable a non-inverted output from the comparator to a device pin.

COMP_OUTPUT_INVERT to enable an inverted output from the comparator to a device pin.

10 October 11, 2007


COMP_OUTPUT_NONE is deprecated and behaves the same as COMP_OUTPUT_-

NORMAL.

Returns:

None.

2.2.2.2

ComparatorIntClear

Clears a comparator interrupt.

Prototype:

void

ComparatorIntClear(unsigned long ulBase, unsigned long ulComp)

Parameters:


ulComp is the index of the comparator.

Description:

The comparator interrupt is cleared, so that it no longer asserts. This must be done in the interrupt handler to keep it from being called again immediately upon exit. Note that for a level triggered interrupt, the interrupt cannot be cleared until it stops asserting.

Returns:

None.

2.2.2.3

ComparatorIntDisable

Disables the comparator interrupt.

Prototype:

void

ComparatorIntDisable(unsigned long ulBase, unsigned long ulComp)

Parameters:



Description:

This function disables generation of an interrupt from the specified comparator. Only comparators whose interrupts are enabled can be reflected to the processor.

Returns:

None.

October 11, 2007 11

Analog Comparator

2.2.2.4

ComparatorIntEnable

Enables the comparator interrupt.

Prototype:

void

ComparatorIntEnable(unsigned long ulBase, unsigned long ulComp)

Parameters:



Description:

This function enables generation of an interrupt from the specified comparator. Only comparators whose interrupts are enabled can be reflected to the processor.

Returns:

None.

2.2.2.5

ComparatorIntRegister

Registers an interrupt handler for the comparator interrupt.

Prototype:

void

ComparatorIntRegister(unsigned long ulBase, unsigned long ulComp, void (*pfnHandler)(void))

Parameters:



pfnHandler is a pointer to the function to be called when the comparator interrupt occurs.

Description:

This sets the handler to be called when the comparator interrupt occurs. This will enable the interrupt in the interrupt controller; it is the interrupt-handler’s responsibility to clear the interrupt source via

ComparatorIntClear() .

See also:

IntRegister()

for important information about registering interrupt handlers.

Returns:

None.

2.2.2.6

ComparatorIntStatus

Gets the current interrupt status.

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Prototype:

tBoolean

ComparatorIntStatus(unsigned long ulBase, unsigned long ulComp, tBoolean bMasked)

Parameters:



bMasked is false if the raw interrupt status is required and true if the masked interrupt status is required.

Description:

This returns the interrupt status for the comparator. Either the raw or the masked interrupt status can be returned.

Returns:

true if the interrupt is asserted and false if it is not asserted.

2.2.2.7

ComparatorIntUnregister

Unregisters an interrupt handler for a comparator interrupt.

Prototype:

void

ComparatorIntUnregister(unsigned long ulBase, unsigned long ulComp)

Parameters:



Description:

This function will clear the handler to be called when a comparator interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

See also:

IntRegister()


Returns:

None.

2.2.2.8

ComparatorRefSet

Sets the internal reference voltage.

Prototype:

void

ComparatorRefSet(unsigned long ulBase, unsigned long ulRef)

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Analog Comparator

Parameters:


ulRef is the desired reference voltage.

Description:

This function will set the internal reference voltage value. The voltage is specified as one of the following values:

COMP_REF_OFF to turn off the reference voltage

COMP_REF_0V to set the reference voltage to 0 V

COMP_REF_0_1375V to set the reference voltage to 0.1375 V



























Returns:

None.

2.2.2.9

ComparatorValueGet

Gets the current comparator output value.

Prototype:

tBoolean

ComparatorValueGet(unsigned long ulBase, unsigned long ulComp)

14 October 11, 2007


Parameters:



Description:

This function retrieves the current value of the comparator output.

Returns:

Returns true if the comparator output is high and false if the comparator output is low.

2.3

Programming Example

The following example shows how to use the comparator API to configure the comparator and read its value.

//

// Configure the internal voltage reference.

//

ComparatorRefSet(COMP_BASE, COMP_REF_1_65V);

//

// Configure a comparator.

//

ComparatorConfigure(COMP_BASE, 0,

(COMP_TRIG_NONE | COMP_INT_BOTH |

COMP_ASRCP_REF | COMP_OUTPUT_NONE));

//

// Delay for some time...

//

//

// Read the comparator output value.

//

ComparatorValueGet(COMP_BASE, 0);

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Analog Comparator

16 October 11, 2007

3


Analog to Digital Converter

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15


3.1

Introduction

The analog to digital converter (ADC) API provides a set of functions for dealing with the ADC.

Functions are provided to configure the sample sequencers, read the captured data, register a sample sequence interrupt handler, and handle interrupt masking/clearing.

The ADC supports up to eight input channels plus an internal temperature sensor. Four sampling sequences, each with configurable trigger events, can be captured. The first sequence will capture up to eight samples, the second and third sequences will capture up to four samples, and the fourth sequence will capture a single sample. Each sample can be the same channel, different channels, or any combination in any order.

The sample sequences have configurable priorities that determine the order in which they are captured when multiple triggers occur simultaneously. The highest priority sequence that is currently triggered will be sampled. Care must be taken with triggers that occur frequently (such as the

“always” trigger); if their priority is too high it is possible to starve the lower priority sequences.

Beginning with Rev C0 of the Stellaris microcontroller, hardware oversampling of the ADC data is available for improved accuracy. An oversampling factor of 2x, 4x, 8x, 16x, 32x, and 64x is supported, but reduces the throughput of the ADC by a corresponding factor. Hardware oversampling is applied uniformly across all sample sequences.

Software oversampling of the ADC data is also available (even when hardware oversampling is available). An oversampling factor of 2x, 4x, and 8x is supported, but reduces the depth of the sample sequences by a corresponding amount. For example, the first sample sequence will capture eight samples; in 4x oversampling mode it can only capture two samples since the first four samples are used over the first oversampled value and the second four samples are used for the second oversampled value. The amount of software oversampling is configured on a per sample sequence basis.

A more sophisticated software oversampling can be used to eliminate the reduction of the sample sequence depth. By increasing the ADC trigger rate by 4x (for example) and averaging four triggers worth of data, 4x oversampling is achieved without any loss of sample sequence capability.

In this case, an increase in the number of ADC triggers (and presumably ADC interrupts) is the consequence. Since this requires adjustments outside of the ADC driver itself, this is not directly supported by the driver (though nothing in the driver prevents it). The software oversampling APIs should not be used in this case.

3.2

API Functions

Functions void

ADCHardwareOversampleConfigure

(unsigned long ulBase, unsigned long ulFactor)

October 11, 2007 17

Analog to Digital Converter void

ADCIntClear

(unsigned long ulBase, unsigned long ulSequenceNum) void

ADCIntDisable


ADCIntEnable


ADCIntRegister

(unsigned long ulBase, unsigned long ulSequenceNum, void (∗pfn-

Handler)(void)) unsigned long

ADCIntStatus

(unsigned long ulBase, unsigned long ulSequenceNum, tBoolean bMasked) void

ADCIntUnregister


ADCProcessorTrigger


ADCSequenceConfigure

(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long ulTrigger, unsigned long ulPriority) long

ADCSequenceDataGet

(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long ∗pulBuffer) void

ADCSequenceDisable


ADCSequenceEnable

(unsigned long ulBase, unsigned long ulSequenceNum) long

ADCSequenceOverflow


ADCSequenceOverflowClear


ADCSequenceStepConfigure

(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long ulStep, unsigned long ulConfig) long

ADCSequenceUnderflow


ADCSequenceUnderflowClear


ADCSoftwareOversampleConfigure

(unsigned long ulBase, unsigned long ulSequence-

Num, unsigned long ulFactor) void

ADCSoftwareOversampleDataGet

(unsigned long ulBase, unsigned long ulSequence-

Num, unsigned long ∗pulBuffer, unsigned long ulCount) void

ADCSoftwareOversampleStepConfigure

(unsigned long ulBase, unsigned long ul-

SequenceNum, unsigned long ulStep, unsigned long ulConfig)

3.2.1


The analog to digital converter API is broken into three groups of functions: those that deal with the sample sequences, those that deal with the processor trigger, and those that deal with interrupt handling.

The sample sequences are configured with

ADCSequenceConfigure()

and

ADCSequenceStep-

Configure() .

They are enabled and disabled with

ADCSequenceEnable()

and

ADCSequence-

Disable() . The captured data is obtained with

ADCSequenceDataGet() . Sample sequence FIFO

overflow and underflow is managed with

ADCSequenceOverflow() ,

ADCSequenceOverflowClear() ,

ADCSequenceUnderflow() , and ADCSequenceUnderflowClear() .

Hardware oversampling of the ADC is controlled with

ADCHardwareOversampleConfigure() .

Software oversampling of the ADC is controlled with

ADCSoftwareOversampleConfigure() ,

ADCSoftwareOversampleStepConfigure() , and

ADCSoftwareOversampleDataGet() .

The processor trigger is generated with

ADCProcessorTrigger() .

The interrupt handler for the ADC sample sequence interrupts are managed with

ADCIntRegister()

and

ADCIntUnregister() .

The sample sequence interrupt sources are managed with

ADCInt-

Disable() ,

ADCIntEnable() ,

ADCIntStatus() , and

ADCIntClear() .

18 October 11, 2007


3.2.2


3.2.2.1

ADCHardwareOversampleConfigure

Configures the hardware oversampling factor of the ADC.

Prototype:

void

ADCHardwareOversampleConfigure(unsigned long ulBase, unsigned long ulFactor)

Parameters:

ulBase is the base address of the ADC module.

ulFactor is the number of samples to be averaged.

Description:

This function configures the hardware oversampling for the ADC, which can be used to provide better resolution on the sampled data. Oversampling is accomplished by averaging multiple samples from the same analog input. Six different oversampling rates are supported; 2x, 4x,

8x, 16x, 32x, and 64x. Specifying an oversampling factor of zero will disable the hardware oversampler.

Hardware oversampling applies uniformly to all sample sequencers. It does not reduce the depth of the sample sequencers like the software oversampling APIs; each sample written into the sample sequence FIFO is a fully oversampled analog input reading.

Enabling hardware averaging increases the precision of the ADC at the cost of throughput. For example, enabling 4x oversampling reduces the throughput of a 250 KSps ADC to 62.5 KSps.

Note:

Hardware oversampling is available beginning with Rev C0 of the Stellaris microcontroller.

Returns:

None.

3.2.2.2

ADCIntClear

Clears sample sequence interrupt source.

Prototype:

void

ADCIntClear(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:


ulSequenceNum is the sample sequence number.

Description:

The specified sample sequence interrupt is cleared, so that it no longer asserts. This must be done in the interrupt handler to keep it from being called again immediately upon exit.

Returns:

None.

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Analog to Digital Converter

3.2.2.3

ADCIntDisable

Disables a sample sequence interrupt.

Prototype:

void

ADCIntDisable(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

This function disables the requested sample sequence interrupt.

Returns:

None.

3.2.2.4

ADCIntEnable

Enables a sample sequence interrupt.

Prototype:

void

ADCIntEnable(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

This function enables the requested sample sequence interrupt. Any outstanding interrupts are cleared before enabling the sample sequence interrupt.

Returns:

None.

3.2.2.5

ADCIntRegister

Registers an interrupt handler for an ADC interrupt.

Prototype:

void

ADCIntRegister(unsigned long ulBase, unsigned long ulSequenceNum, void (*pfnHandler)(void))

Parameters:


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pfnHandler is a pointer to the function to be called when the ADC sample sequence interrupt occurs.

Description:

This function sets the handler to be called when a sample sequence interrupt occurs. This will enable the global interrupt in the interrupt controller; the sequence interrupt must be enabled with

ADCIntEnable() . It is the interrupt handler’s responsibility to clear the interrupt source via

ADCIntClear() .

See also:

IntRegister()


Returns:

None.

3.2.2.6

ADCIntStatus


Prototype:

unsigned long

ADCIntStatus(unsigned long ulBase, unsigned long ulSequenceNum, tBoolean bMasked)

Parameters:



bMasked is false if the raw interrupt status is required and true if the masked interrupt status is required.

Description:

This returns the interrupt status for the specified sample sequence. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:

The current raw or masked interrupt status.

3.2.2.7

ADCIntUnregister

Unregisters the interrupt handler for an ADC interrupt.

Prototype:

void

ADCIntUnregister(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:


October 11, 2007 21



Description:

This function unregisters the interrupt handler. This will disable the global interrupt in the interrupt controller; the sequence interrupt must be disabled via

ADCIntDisable() .

See also:

IntRegister()


Returns:

None.

3.2.2.8

ADCProcessorTrigger

Causes a processor trigger for a sample sequence.

Prototype:

void

ADCProcessorTrigger(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

This function triggers a processor-initiated sample sequence if the sample sequence trigger is configured to ADC_TRIGGER_PROCESSOR.

Returns:

None.

3.2.2.9

ADCSequenceConfigure

Configures the trigger source and priority of a sample sequence.

Prototype:

void

ADCSequenceConfigure(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long ulTrigger, unsigned long ulPriority)

Parameters:



ulTrigger is the trigger source that initiates the sample sequence; must be one of the ADC_-

TRIGGER_∗ values.

ulPriority is the relative priority of the sample sequence with respect to the other sample sequences.

22 October 11, 2007


Description:

This function configures the initiation criteria for a sample sequence. Valid sample sequences range from zero to three; sequence zero will capture up to eight samples, sequences one and two will capture up to four samples, and sequence three will capture a single sample. The trigger condition and priority (with respect to other sample sequence execution) is set.

The parameter ulTrigger can take on the following values:

ADC_TRIGGER_PROCESSOR - A trigger generated by the processor, via the

ADCProcessorTrigger()

function.

ADC_TRIGGER_COMP0 - A trigger generated by the first analog comparator; configured with

ComparatorConfigure() .

ADC_TRIGGER_COMP1 - A trigger generated by the second analog comparator; configured with


ADC_TRIGGER_COMP2 - A trigger generated by the third analog comparator; configured with


ADC_TRIGGER_EXTERNAL - A trigger generated by an input from the Port B4 pin.

ADC_TRIGGER_TIMER - A trigger generated by a timer; configured with

TimerControl-

Trigger() .

ADC_TRIGGER_PWM0 - A trigger generated by the first PWM generator; configured with

PWMGenIntTrigEnable() .

ADC_TRIGGER_PWM1 - A trigger generated by the second PWM generator; configured with


ADC_TRIGGER_PWM2 - A trigger generated by the third PWM generator; configured with


ADC_TRIGGER_ALWAYS - A trigger that is always asserted, causing the sample sequence to capture repeatedly (so long as there is not a higher priority source active).

Note that not all trigger sources are available on all Stellaris family members; consult the data sheet for the device in question to determine the availability of triggers.

The parameter ulPriority is a value between 0 and 3, where 0 represents the highest priority and 3 the lowest. Note that when programming the priority among a set of sample sequences, each must have unique priority; it is up to the caller to guarantee the uniqueness of the priorities.

Returns:

None.

3.2.2.10 ADCSequenceDataGet

Gets the captured data for a sample sequence.

Prototype:

long

ADCSequenceDataGet(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long *pulBuffer)

Parameters:



October 11, 2007 23


pulBuffer is the address where the data is stored.

Description:

This function copies data from the specified sample sequence output FIFO to a memory resident buffer. The number of samples available in the hardware FIFO are copied into the buffer, which is assumed to be large enough to hold that many samples. This will only return the samples that are presently available, which may not be the entire sample sequence if it is in the process of being executed.

Returns:

Returns the number of samples copied to the buffer.

3.2.2.11 ADCSequenceDisable

Disables a sample sequence.

Prototype:

void

ADCSequenceDisable(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

Prevents the specified sample sequence from being captured when its trigger is detected. A sample sequence should be disabled before it is configured.

Returns:

None.

3.2.2.12 ADCSequenceEnable

Enables a sample sequence.

Prototype:

void

ADCSequenceEnable(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

Allows the specified sample sequence to be captured when its trigger is detected. A sample sequence must be configured before it is enabled.

Returns:

None.

24 October 11, 2007


3.2.2.13 ADCSequenceOverflow

Determines if a sample sequence overflow occurred.

Prototype:

long

ADCSequenceOverflow(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

This determines if a sample sequence overflow has occurred. This will happen if the captured samples are not read from the FIFO before the next trigger occurs.

Returns:

Returns zero if there was not an overflow, and non-zero if there was.

3.2.2.14 ADCSequenceOverflowClear

Clears the overflow condition on a sample sequence.

Prototype:

void

ADCSequenceOverflowClear(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

This will clear an overflow condition on one of the sample sequences. The overflow condition must be cleared in order to detect a subsequent overflow condition (it otherwise causes no harm).

Returns:

None.

3.2.2.15 ADCSequenceStepConfigure

Configure a step of the sample sequencer.

Prototype:

void

ADCSequenceStepConfigure(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long ulStep, unsigned long ulConfig)

October 11, 2007 25


Parameters:



ulStep is the step to be configured.

ulConfig is the configuration of this step; must be a logical OR of ADC_CTL_TS, ADC_CTL_-

IE, ADC_CTL_END, ADC_CTL_D, and one of the input channel selects (ADC_CTL_CH0 through

ADC_CTL_CH7).

Description:

This function will set the configuration of the ADC for one step of a sample sequence. The

ADC can be configured for single-ended or differential operation (the

ADC_CTL_D bit selects differential operation when set), the channel to be sampled can be chosen (the

ADC_CTL_-

CH0 through ADC_CTL_CH7 values), and the internal temperature sensor can be selected

(the ADC_CTL_TS bit). Additionally, this step can be defined as the last in the sequence (the

ADC_CTL_END bit) and it can be configured to cause an interrupt when the step is complete

(the ADC_CTL_IE bit). The configuration is used by the ADC at the appropriate time when the trigger for this sequence occurs.

The ulStep parameter determines the order in which the samples are captured by the ADC when the trigger occurs. It can range from zero to seven for the first sample sequence, from zero to three for the second and third sample sequence, and can only be zero for the fourth sample sequence.

Differential mode only works with adjacent channel pairs (e.g. 0 and 1). The channel select must be the number of the channel pair to sample (e.g.

ADC_CTL_CH0 for 0 and 1, or

ADC_CTL_CH1 for 2 and 3) or undefined results will be returned by the ADC. Additionally, if differential mode is selected when the temperature sensor is being sampled, undefined results will be returned by the ADC.

It is the responsibility of the caller to ensure that a valid configuration is specified; this function does not check the validity of the specified configuration.

Returns:

None.

3.2.2.16 ADCSequenceUnderflow

Determines if a sample sequence underflow occurred.

Prototype:

long

ADCSequenceUnderflow(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

This determines if a sample sequence underflow has occurred. This will happen if too many samples are read from the FIFO.

Returns:

Returns zero if there was not an underflow, and non-zero if there was.

26 October 11, 2007


3.2.2.17 ADCSequenceUnderflowClear

Clears the underflow condition on a sample sequence.

Prototype:

void

ADCSequenceUnderflowClear(unsigned long ulBase, unsigned long ulSequenceNum)

Parameters:



Description:

This will clear an underflow condition on one of the sample sequences. The underflow condition must be cleared in order to detect a subsequent underflow condition (it otherwise causes no harm).

Returns:

None.

3.2.2.18 ADCSoftwareOversampleConfigure

Configures the software oversampling factor of the ADC.

Prototype:

void

ADCSoftwareOversampleConfigure(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long ulFactor)

Parameters:



ulFactor is the number of samples to be averaged.

Description:

This function configures the software oversampling for the ADC, which can be used to provide better resolution on the sampled data. Oversampling is accomplished by averaging multiple samples from the same analog input. Three different oversampling rates are supported; 2x,

4x, and 8x.

Oversampling is only supported on the sample sequencers that are more than one sample in depth (i.e. the fourth sample sequencer is not supported). Oversampling by 2x (for example) divides the depth of the sample sequencer by two; so 2x oversampling on the first sample sequencer can only provide four samples per trigger. This also means that 8x oversampling is only available on the first sample sequencer.

Returns:

None.

October 11, 2007 27


3.2.2.19 ADCSoftwareOversampleDataGet

Gets the captured data for a sample sequence using software oversampling.

Prototype:

void

ADCSoftwareOversampleDataGet(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long *pulBuffer, unsigned long ulCount)

Parameters:



pulBuffer is the address where the data is stored.

ulCount is the number of samples to be read.

Description:

This function copies data from the specified sample sequence output FIFO to a memory resident buffer with software oversampling applied. The requested number of samples are copied into the data buffer; if there are not enough samples in the hardware FIFO to satisfy this many oversampled data items then incorrect results will be returned. It is the caller’s responsibility to read only the samples that are available and wait until enough data is available, for example as a result of receiving an interrupt.

Returns:

None.

3.2.2.20 ADCSoftwareOversampleStepConfigure

Configures a step of the software oversampled sequencer.

Prototype:

void

ADCSoftwareOversampleStepConfigure(unsigned long ulBase, unsigned long ulSequenceNum, unsigned long ulStep, unsigned long ulConfig)

Parameters:



ulStep is the step to be configured.

ulConfig is the configuration of this step.

Description:

This function configures a step of the sample sequencer when using the software oversampling feature. The number of steps available depends on the oversampling factor set by

ADCSoftwareOversampleConfigure() . The value of ulConfig is the same as defined for

ADCSequenceStepConfigure() .

Returns:

None.

28 October 11, 2007


3.3


The following example shows how to use the ADC API to initialize a sample sequence for processor triggering, trigger the sample sequence, and then read back the data when it is ready.

unsigned long ulValue;

//

// Enable the first sample sequence to capture the value of channel 0 when

// the processor trigger occurs.

//

ADCSequenceConfigure(ADC_BASE, 0, ADC_TRIGGER_PROCESSOR, 0);

ADCSequenceStepConfigure(ADC_BASE, 0, 0,

ADC_CTL_IE | ADC_CTL_END | ADC_CTL_CH0);

ADCSequenceEnable(ADC_BASE, 0);

//

// Trigger the sample sequence.

//

ADCProcessorTrigger(ADC_BASE, 0);

//

// Wait until the sample sequence has completed.

// while(!ADCIntStatus(ADC_BASE, 0, false))

{

}

//

// Read the value from the ADC.

//

ADCSequenceDataGet(ADC_BASE, 0, &ulValue);

October 11, 2007 29


30 October 11, 2007

4


Controller Area Network (CAN)

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29


4.1

Introduction

The Controller Area Network (CAN) APIs provide a set of functions for accessing the Stellaris CAN modules. Functions are provided to configure the CAN controllers, configure message objects, and manage CAN interrupts.

The Stellaris CAN module provides hardware processing of the CAN data link layer. It can be configured with message filters and preloaded message data so that it can autonomously send and receive messages on the bus, and notify the application accordingly. It automatically handles generation and checking of CRCs, error processing, and retransmission of CAN messages.

The message objects are stored in the CAN controller and provide the main interface for the CAN module on the CAN bus. There are 32 message objects that can each be programmed to handle a separate message ID, or can be chained together for a sequence of frames with the same ID.

The message identifier filters provide masking that can be programmed to match any or all of the message ID bits, and frame types.

4.2

API Functions

Data Structures

tCANBitClkParms

tCANMsgObject

Defines

MSG_OBJ_STATUS_MASK

Enumerations

tCANIntFlags tCANIntStsReg tCANObjFlags tCANStatusCtrl

tCANStsReg tMsgObjType

October 11, 2007 31

Controller Area Network (CAN)

Functions void

CANDisable

(unsigned long ulBase) void

CANEnable

(unsigned long ulBase) tBoolean

CANErrCntrGet

(unsigned long ulBase, unsigned long ∗pulRxCount, unsigned long

∗pulTxCount) void

CANGetBitTiming

(unsigned long ulBase,

tCANBitClkParms

∗pClkParms) long

CANGetIntNumber


CANInit


CANIntClear

(unsigned long ulBase, unsigned long ulIntClr) void

CANIntDisable

(unsigned long ulBase, unsigned long ulIntFlags) void

CANIntEnable


CANIntRegister

(unsigned long ulBase, void (∗pfnHandler)(void)) unsigned long

CANIntStatus


tCANIntStsReg

eIntStsReg) void

CANIntUnregister


CANMessageClear

(unsigned long ulBase, unsigned long ulObjID) void

CANMessageGet

(unsigned long ulBase, unsigned long ulObjID,

tCANMsgObject

∗pMsg-

Object, tBoolean bClrPendingInt) void

CANMessageSet

(unsigned long ulBase, unsigned long ulObjID,

tCANMsgObject

∗pMsg-

Object,

tMsgObjType

eMsgType) void

CANReadDataReg

(unsigned char ∗pucData, unsigned long ∗pulRegister, int iSize) unsigned long

CANReadReg

(unsigned long ulRegAddress) tBoolean

CANRetryGet


CANRetrySet

(unsigned long ulBase, tBoolean bAutoRetry) void

CANSetBitTiming


tCANBitClkParms

∗pClkParms) unsigned long

CANStatusGet


tCANStsReg

eStatusReg) void

CANWriteDataReg

(unsigned char ∗pucData, unsigned long ∗pulRegister, int iSize) void

CANWriteReg

(unsigned long ulRegAddress, unsigned long ulRegValue)

4.2.1


The CAN APIs provide all of the functions needed by the application to implement an interrupt driven CAN stack. These functions may be used to control any of the available CAN ports on a

Stellaris microcontroller, and can be used with one port without causing conflicts with the other port.

The CAN module is disabled by default, so the the

CANInit()

function must be called before any other CAN functions are called. This call initializes the message objects to a safe state prior to enabling the controller on the CAN bus. Also, the bit timing values must be programmed prior to enabling the CAN controller. The

CANSetBitTiming()

function should be called with the appropriate bit timing values for the CAN bus. Once these two functions have been called, a CAN controller can be enabled using the

CANEnable() , and later disabled again using CANDisable()

if needed. Calling

CANDisable()

does not reinitialize a CAN controller, so it can be used to temporarily remove a CAN controller from the bus.

The CAN controller is highly configurable and contains 32 message objects that can be programmed to automatically transmit and receive CAN messages under certain conditions. Message objects allow the application to perform some actions automatically without interaction from the microcontroller. Some examples of these actions are the following:

32 October 11, 2007

Stellaris Peripheral Driver Library User’s Guide send a data frame immediately send a data frame when a matching remote frame is seen on the CAN bus receive a specific data frame receive data frames that match a certain identifier pattern

To configure message objects to perform any of these actions, the application must first set up one of the 32 message objects using

CANMessageSet() . This function must be used to configure a

message object to send data, or to configure a message object to receive data. Each message object can be configured to generate interrupts on transmission or reception of CAN messages.

When data is received from the CAN bus, the application can use the

CANMessageGet()

function to read the received message. This function can also be used to read a message object that is already configured in order to populate a message structure prior to making changes to the configuration of a message object. Reading the message object using this function will also clear any pending interrupt on the message object.

Once a message object has been configured using

CANMessageSet() , it has allocated the mes-

sage object and will continue to perform its programmed function unless it is released with a call to

CANMessageClear() . The application is not required to clear out a message object before setting

it with a new configuration, because each time

CANMessageSet()

is called, it will overwrite any previously programmed configuration.

The 32 message objects are identical except for priority. The lowest numbered message objects have the highest priority. Priority affects operation in two ways. First if multiple actions are ready at the same time, the one with the highest priority message object will occur first. And second, when multiple message objects have interrupts pending, the highest priority will be presented first when reading the interrupt status. It is up to the application to manage the 32 message objects as a resource, and determine the best method for allocating and releasing them.

The CAN controller can generate interrupts on several conditions: when any message object transmits a message when any message object receives a message on warning conditions such as an error counter reaching a limit or occurrence of various bus errors on controller error conditions such as entering the bus-off state

An interrupt handler must be installed in order to process CAN interrupts. If dynamic interrupt configuration is desired, the

CANIntRegister()

can be used to register the interrupt handler. This will place the vector in a RAM based vector table. If instead, the application uses a pre-loaded vector table in flash, then the CAN controller handler should be entered in the appropriate slot in the vector table. In this case

CANIntRegister()

is not needed, but the interrupt will need to be enabled on the host processor master interrupt controller using the

IntEnable()

function. The CAN module interrupts are enabled using the

CANIntEnable()

function. They can be disabled by using the

CANIntDisable()

function.

Once CAN interrupts are enabled, the handler will be invoked whenever a CAN interrupt is triggered.

The handler can determines which condition caused the interrupt by using the

CANIntStatus()

function. Multiple conditions can be pending when an interrupt occurs, so the handler must be designed to process all pending interrupt conditions before exiting. Each interrupt condition must be cleared before exiting the handler. There are two ways to do this. The

CANIntClear()

function will clear a specific interrupt condition without further action required by the handler. However, the handler can also clear the condition by performing certain actions. If the interrupt is a status interrupt, the interrupt can be cleared by reading the status register with

CANStatusGet() . If the

October 11, 2007 33

Controller Area Network (CAN) interrupt is caused by one of the message objects, then it can be cleared by reading the message object using

CANMessageGet() .

There are several status registers that can be used to help the application manage the controller.

The status registers are read using the

CANStatusGet()

function. There is a controller status register that provides general status information such as error or warning conditions. There are also several status registers that provide information about all of the message objects at once using a

32-bit bit map of the status, with one bit representing each message object. These status registers can be used to determine: which message objects have unprocessed received data which message objects have pending transmission requests which message objects are allocated for use

The CAN controller also supports several test modes. With the test modes you can do the following: force the TX pin into a known state cause the sample clock to appear on the TX pin, which could be used to help diagnose bus timing put the controller into an internal loopback mode put the controller into a "silent" mode where it will operate and receive messages, but will not transmit anything onto the CAN bus put the controller into a basic read/write mode where the message objects are not used and a simple read/write interface is used to immediately send and receive messages without any automatic processing features

The application can put the CAN controller into a test mode using the CANTestSet() function. If the controller is placed in this mode, then the functions CANTestRead() and CANTestWrite() should be used to receive and send messages on the CAN bus. These functions will directly send a message, or receive a message if any are pending. In this test mode there is no automatic filtering or processing.

4.2.2

Data Structure Documentation

4.2.2.1

tCANBitClkParms

Definition:

typedef struct

{ unsigned int uSyncPropPhase1Seg; unsigned int uPhase2Seg; unsigned int uSJW; unsigned int uQuantumPrescaler;

} tCANBitClkParms

Members:

uSyncPropPhase1Seg This value holds the sum of the Synchronization, Propagation, and

Phase Buffer 1 segments, measured in time quanta. The valid values for this setting range from 2 to 16.

34 October 11, 2007


uPhase2Seg This value holds the Phase Buffer 2 segment in time quanta. The valid values for this setting range from 1 to 8.

uSJW This value holds the Resynchronization Jump Width in time quanta. The valid values for this setting range from 1 to 4.

uQuantumPrescaler This value holds the CAN_CLK divider used to determine time quanta.

The valid values for this setting range from 1 to 1023.

Description:

This structure is used for encapsulating the values associated with setting up the bit timing for a

CAN controller. The structure is used when calling the CANGetBitTiming and CANSetBitTiming functions.

4.2.2.2

tCANMsgObject

Definition:

typedef struct

{ unsigned long ulMsgID; unsigned long ulMsgIDMask; unsigned long ulFlags; unsigned long ulMsgLen; unsigned char *pucMsgData;

} tCANMsgObject

Members:

ulMsgID The CAN message identifier used for 11 or 29 bit identifiers.

ulMsgIDMask The message identifier mask used when identifier filtering is enabled.

ulFlags This value holds various status flags and settings specified by tCANObjFlags.

ulMsgLen This value is the number of bytes of data in the message object.

pucMsgData This is a pointer to the message object’s data.

Description:

This structure used for encapsulating all the items associated with a CAN message object in the CAN controller.

4.2.3

Define Documentation

4.2.3.1

MSG_OBJ_STATUS_MASK

Definition:

#define MSG_OBJ_STATUS_MASK

Description:

This define is used with the

tCANObjFlags

enumerated values to allow checking only status flags and not configuration flags.

October 11, 2007 35


4.2.4

Enumeration Documentation

4.2.4.1

tCANIntFlags

Description:

These definitions are used to specify interrupt sources to

CANIntEnable()

and

CANIntDisable() .

Enumerators:

CAN_INT_ERROR This flag is used to allow a CAN controller to generate error interrupts.

CAN_INT_STATUS This flag is used to allow a CAN controller to generate status interrupts.

CAN_INT_MASTER This flag is used to allow a CAN controller to generate any CAN interrupts. If this is not set then no interrupts will be generated by the CAN controller.

4.2.4.2

tCANIntStsReg

Description:

This data type is used to identify the interrupt status register. This is used when calling the a

CANIntStatus()

function.

Enumerators:

CAN_INT_STS_CAUSE Read the CAN interrupt status information.

CAN_INT_STS_OBJECT Read a message object’s interrupt status.

4.2.4.3

tCANObjFlags

Description:

These are the flags used by the

tCANMsgObject

variable when calling the the

CANMessage-

Set()

and

CANMessageGet()

APIs.

Enumerators:

MSG_OBJ_TX_INT_ENABLE This indicates that transmit interrupts should be enabled, or are enabled.

MSG_OBJ_RX_INT_ENABLE This indicates that receive interrupts should be enabled or are enabled.

MSG_OBJ_EXTENDED_ID This indicates that a message object will use or is using an extended identifier.

MSG_OBJ_USE_ID_FILTER This indicates that a message object will use or is using filtering based on the object’s message Identifier.

MSG_OBJ_NEW_DATA This indicates that new data was available in the message object.

MSG_OBJ_DATA_LOST This indicates that data was lost since this message object was last read.

MSG_OBJ_USE_DIR_FILTER This indicates that a message object will use or is using filtering based on the direction of the transfer. If the direction filtering is used then ID filtering must also be enabled.

MSG_OBJ_USE_EXT_FILTER This indicates that a message object will use or is using message identifier filtering based of the the extended identifier. If the extended identifier filtering is used then ID filtering must also be enabled.

MSG_OBJ_REMOTE_FRAME This indicates that a message object is a remote frame.

MSG_OBJ_NO_FLAGS This indicates that a message object has no flags set.

36 October 11, 2007


4.2.4.4

tCANStatusCtrl

Description:

The following enumeration contains all error or status indicators that can be returned when calling the

CANStatusGet()

API.

Enumerators:

CAN_STATUS_BUS_OFF CAN controller has entered a Bus Off state.

CAN_STATUS_EWARN CAN controller error level has reached warning level.

CAN_STATUS_EPASS CAN controller error level has reached error passive level.

CAN_STATUS_RXOK A message was received successfully since the last read of this status.

CAN_STATUS_TXOK A message was transmitted successfully since the last read of this status.

CAN_STATUS_LEC_MSK This is the mask for the last error code field.

CAN_STATUS_LEC_NONE There was no error.

CAN_STATUS_LEC_STUFF A bit stuffing error has occurred.

CAN_STATUS_LEC_FORM A formatting error has occurred.

CAN_STATUS_LEC_ACK An acknowledge error has occurred.

CAN_STATUS_LEC_BIT1 The bus remained a bit level of 1 for longer than is allowed.

CAN_STATUS_LEC_BIT0 The bus remained a bit level of 0 for longer than is allowed.

CAN_STATUS_LEC_CRC A CRC error has occurred.

CAN_STATUS_LEC_MASK This is the mask for the CAN Last Error Code (LEC).

4.2.4.5

tCANStsReg

Description:

This data type is used to identify which of the several status registers to read when calling the

CANStatusGet()

function.

Enumerators:

CAN_STS_CONTROL Read the full CAN controller status.

CAN_STS_TXREQUEST Read the full 32 bit mask of message objects with a transmit request set.

CAN_STS_NEWDAT Read the full 32 bit mask of message objects with a new data available.

CAN_STS_MSGVAL Read the full 32 bit mask of message objects that are enabled.

4.2.4.6

tMsgObjType

Description:

This definition is used to determine the type of message object that will be set up via a call to the

CANMessageSet()

API.

Enumerators:

MSG_OBJ_TYPE_TX Transmit message object.

MSG_OBJ_TYPE_TX_REMOTE Transmit remote request message object.

October 11, 2007 37


MSG_OBJ_TYPE_RX Receive message object.

MSG_OBJ_TYPE_RX_REMOTE Receive remote request message object.

MSG_OBJ_TYPE_RXTX_REMOTE Remote frame receive remote, with auto-transmit message object.

4.2.5


4.2.5.1

CANDisable

Disables the CAN controller.

Prototype:

void

CANDisable(unsigned long ulBase)

Parameters:

ulBase is the base address of the CAN controller to disable.

Description:

Disables the CAN controller for message processing. When disabled, the controller will no longer automatically process data on the CAN bus. The controller can be restarted by calling

CANEnable() . The state of the CAN controller and the message objects in the controller are

left as they were before this call was made.

Returns:

None.

4.2.5.2

CANEnable

Enables the CAN controller.

Prototype:

void

CANEnable(unsigned long ulBase)

Parameters:

ulBase is the base address of the CAN controller to enable.

Description:

Enables the CAN controller for message processing. Once enabled, the controller will automatically transmit any pending frames, and process any received frames. The controller can be stopped by calling

CANDisable() . Prior to calling CANEnable() ,

CANInit()

should have been called to initialize the controller and the CAN bus clock should be configured by calling

CANSetBitTiming() .

Returns:

None.

38 October 11, 2007


4.2.5.3

CANErrCntrGet

Reads the CAN controller error counter register.

Prototype:

tBoolean

CANErrCntrGet(unsigned long ulBase, unsigned long *pulRxCount, unsigned long *pulTxCount)

Parameters:

ulBase is the base address of the CAN controller.

pulRxCount is a pointer to storage for the receive error counter.

pulTxCount is a pointer to storage for the transmit error counter.

Description:

Reads the error counter register and returns the transmit and receive error counts to the caller along with a flag indicating if the controller receive counter has reached the error passive limit. The values of the receive and transmit error counters are returned through the pointers provided as parameters.

After this call, ∗pulRxCount will hold the current receive error count and ∗pulTxCount will hold the current transmit error count.

Returns:

true if the receive error count has reached the error passive limit.

false if the error count is below the error passive limit.

4.2.5.4

CANGetBitTiming

Reads the current settings for the CAN controller bit timing.

Prototype:

void

CANGetBitTiming(unsigned long ulBase,

tCANBitClkParms

*pClkParms)

Parameters:


pClkParms is a pointer to a structure to hold the timing parameters.

Description:

This function reads the current configuration of the CAN controller bit clock timing, and stores the resulting information in the structure supplied by the caller. Refer to

CANSetBitTiming()

for the meaning of the values that are returned in the structure pointed to by pClkParms.

Returns:

None.

October 11, 2007 39


4.2.5.5

CANGetIntNumber

Returns the CAN controller interrupt number.

Prototype:

long

CANGetIntNumber(unsigned long ulBase)

Parameters:

ulBase is the base address of the selected CAN controller

Description:

Given a CAN controller base address, returns the corresponding interrupt number.

Returns:

Returns a CAN interrupt number, or -1 if ulPort is invalid.

4.2.5.6

CANInit

Initializes the CAN controller after reset.

Prototype:

void

CANInit(unsigned long ulBase)

Parameters:


Description:

After reset, the CAN controller is left in the disabled state. However, the memory used for message objects contains undefined values and must be cleared prior to enabling the CAN controller the first time. This prevents unwanted transmission or reception of data before the message objects are configured. This function must be called before enabling the controller the first time.

Returns:

None.

4.2.5.7

CANIntClear

This call is used to clears a CAN interrupt source.

Prototype:

void

CANIntClear(unsigned long ulBase, unsigned long ulIntClr)

Parameters:


ulIntClr is a value indicating which interrupt source to clear

40 October 11, 2007


Description:

This function can be used to clear a specific interrupt source. The parameter ulIntClr should be one of the following values:

CAN_INT_INTID_STATUS - Clears a status interrupt.

1-32 - Clear the specified message object interrupt

It is not necessary to use this function to clear an interrupt. This should only be used if the application wants to clear an interrupt source without taking the normal interrupt action.

Normally, the status interrupt is cleared by reading the controller status, by calling

CANStatus-

Get() . A specific message object interrupt is normally cleared by reading the message object

(see

CANMessageGet() ).

Returns:

None.

4.2.5.8

CANIntDisable

Disables individual CAN controller interrupt sources.

Prototype:

void

CANIntDisable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:


ulIntFlags is the bit mask of the interrupt sources to be disabled.

Description:

Disables the specified CAN controller interrupt sources. Only enabled interrupt sources can cause a processor interrupt.

The parameter ulIntFlags has the same definition as in the function

CANIntEnable() .

Returns:

None.

4.2.5.9

CANIntEnable

Enables individual CAN controller interrupt sources.

Prototype:

void

CANIntEnable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:


ulIntFlags is the bit mask of the interrupt sources to be enabled.

October 11, 2007 41


Description:

Enables specific interrupt sources of the CAN controller. Only enabled sources will cause a processor interrupt.

The parameter ulIntFlags is the logical OR of any of the following:

CAN_INT_ERROR - controller error condition has occurred

CAN_INT_STATUS - a message transfer completed, or bus error detected

CAN_INT_MASTER - allow CAN controller to generate interrupts

In order to generate any interrupts, CAN_INT_MASTER must be enabled. Further, for any particular transaction from a message object to generate an interrupt, that message object must have interrupts enabled (see

CANMessageSet() ). CAN_INT_ERROR will generate an

interrupt if the controller enters the "bus off" condition, or if the error counters reach a limit.

CAN_INT_STATUS will generate an interrupt under quite a few status conditions and may provide more interrupts than the application needs to handle. When an interrupt occurs, use

CANIntStatus()

to determine the cause.

Returns:

None.

4.2.5.10 CANIntRegister

Registers an interrupt handler for the CAN controller.

Prototype:

void

CANIntRegister(unsigned long ulBase, void (*pfnHandler)(void))

Parameters:


pfnHandler is a pointer to the function to be called when the enabled CAN interrupts occur.

Description:

This function registers the interrupt handler in the interrupt vector table, and enables CAN interrupts on the interrupt controller; specific CAN interrupt sources must be enabled using

CANIntEnable() . The interrupt handler being registered must clear the source of the interrupt

using

CANIntClear() ;

If the application is using a static interrupt vector table stored in flash, then it is not necessary to register the interrupt handler this way. Instead,

IntEnable()

should be used to enable CAN interrupts on the interrupt controller.

See also:

IntRegister()


Returns:

None.

42 October 11, 2007


4.2.5.11 CANIntStatus

Returns the current CAN controller interrupt status.

Prototype:

unsigned long

CANIntStatus(unsigned long ulBase,

tCANIntStsReg

eIntStsReg)

Parameters:


eIntStsReg indicates which interrupt status register to read

Description:

Returns the value of one of two interrupt status registers. The interrupt status register read is determined by the parameter eIntStsReg, which can have one of the following values:

CAN_INT_STS_CAUSE - indicates the cause of the interrupt

CAN_INT_STS_OBJECT - indicates pending interrupts of all message objects

CAN_INT_STS_CAUSE returns the value of the controller interrupt register and indicates the cause of the interrupt. It will be a value of CAN_INT_INTID_STATUS if the cause is a status interrupt. In this case, the status register should be read with the

CANStatusGet()

function.

Calling this function to read the status will also clear the status interrupt. If the value of the interrupt register is in the range 1-32, then this indicates the number of the highest priority message object that has an interrupt pending. The message object interrupt can be cleared by using the

CANIntClear()

function, or by reading the message using

CANMessageGet()

in the case of a received message. The interrupt handler can read the interrupt status again to make sure all pending interrupts are cleared before returning from the interrupt.

CAN_INT_STS_OBJECT returns a bit mask indicating which message objects have pending interrupts. This can be used to discover all of the pending interrupts at once, as opposed to repeatedly reading the interrupt register by using CAN_INT_STS_CAUSE.

Returns:

The value of one of the interrupt status registers.

4.2.5.12 CANIntUnregister

Unregisters an interrupt handler for the CAN controller.

Prototype:

void

CANIntUnregister(unsigned long ulBase)

Parameters:

ulBase is the base address of the controller.

Description:

This function unregisters the previously registered interrupt handler and disables the interrupt on the interrupt controller.

See also:

IntRegister()


October 11, 2007 43


Returns:

None.

4.2.5.13 CANMessageClear

Clears a message object so that it is no longer used

Prototype:

void

CANMessageClear(unsigned long ulBase, unsigned long ulObjID)

Parameters:


ulObjID is the message object number to disable (1-32)

Description:

This function frees the specified message object from use. Once a message object has been

"cleared" it will no longer automatically send or receive messages, or generate interrupts.

Returns:

None.

4.2.5.14 CANMessageGet

Reads a CAN message from one of the message object buffers

Prototype:

void

CANMessageGet(unsigned long ulBase, unsigned long ulObjID,

tCANMsgObject

*pMsgObject, tBoolean bClrPendingInt)

Parameters:


ulObjID is the object number to read (1-32)

pMsgObject points to a structure containing message object fields

bClrPendingInt indicates whether an associated interrupt should be cleared

Description:

This function is used to read the contents of one of the 32 message objects in the CAN controller, and return it to the caller. The data returned is stored in the fields of the caller supplied structure pointed to by pMsgObject. The data consists of all of the parts of a CAN message, plus some control and status information.

Normally this is used to read a message object that has received and stored a CAN message with a certain identifier. However this could also be used to read the contents of a message object in order to load the fields of the structure in case only part of the structure needs to be changed from a previous setting.

44 October 11, 2007


When using CANMessageGet, all of the same fields of the structure are populated in the same way as when the

CANMessageSet()

function is used, with the following exceptions: pMsgObject->ulFlags:

MSG_OBJ_NEW_DATA indicates if this is new data since the last time it was read

MSG_OBJ_DATA_LOST indicates that at least one message was received on this message object, and not read by the host before being overwritten.

Returns:

None.

4.2.5.15 CANMessageSet

Configures a message object in the CAN controller.

Prototype:

void

CANMessageSet(unsigned long ulBase, unsigned long ulObjID,

tCANMsgObject

*pMsgObject,

tMsgObjType

eMsgType)

Parameters:


ulObjID is the object number to configure (1-32)

pMsgObject is a pointer to a structure containing message object settings.

eMsgType Indicates what type of message this object is.

Description:

This function is used to configure any one of the 32 message objects in the CAN controller.

A message object can be configured as any type of CAN message object as well as several options for automatic transmission and reception. This call also allows the message object to be configured to generate interrupts on completion of message receipt or transmission. The message object can also be configured with a filter/mask so that actions are only taken when a message that meets certain parameters is seen on the CAN bus.

The eMsgType parameter must be one of the following values:

MSG_OBJ_TYPE_TX - CAN transmit message object.

MSG_OBJ_TYPE_TX_REMOTE - CAN transmit remote request message object.

MSG_OBJ_TYPE_RX - CAN receive message object.

MSG_OBJ_TYPE_RX_REMOTE - CAN receive remote request message object.

MSG_OBJ_TYPE_RXTX_REMOTE - CAN remote frame receive remote, then transmit message object.

The message object pointed to by pMsgObject must be populated by the caller, as follows: ulMsgID - contains the message ID, either 11 or 29 bits.

ulMsgIDMask - mask of bits from ulMsgID that must match if identifier filtering is enabled.

ulFlags

• Set MSG_OBJ_TX_INT_ENABLE flag to enable interrupt on transmission.

October 11, 2007 45


• Set MSG_OBJ_RX_INT_ENABLE flag to enable interrupt on receipt.

• Set MSG_OBJ_USE_ID_FILTER flag to enable filtering based on the identifier mask specified by ulMsgIDMask .

ulMsgLen - the number of bytes in the message data. This should be non-zero even for a remote frame - it should match the expected bytes of the data responding data frame.

pucMsgData - points to a buffer containing up to 8 bytes of data for a data frame

To send a data frame or remote frame directly, take the following steps: set tMsgObjType to MSG_OBJ_TYPE_TX.

set ulMsgID to the message ID.

set ulFlags Set MSG_OBJ_TX_INT_ENABLE to to get an interrupt when the message is sent. To disable filtering based on message identifiers, do not set MSG_OBJ_USE_ID_-

FILTER.

set ulMsgLen to the number of bytes in the data frame.

set pucMsgData to point to an array containing the bytes in the message (if a data frame, n/a if remote frame, though it is a good idea to set this to point to a valid buffer).

call this function with ulObjID set to one of the 32 object buffers.

To receive a specific data frame, take the following steps: set tMsgObjType to MSG_OBJ_TYPE_RX.

set ulMsgID to the full message ID, or a partial mask to use partial ID matching.

set ulMsgIDMask bits that should be used for masking during comparison.

ulFlags

• Set MSG_OBJ_TX_INT_ENABLE flag to be interrupted when the data frame is received.

• Set MSG_OBJ_USE_ID_FILTER flag to enable identifier based filtering.

set ulMsgLen to the number of bytes in the expected data frame the buffer pointed to by pucMsgData is not used for this call call this function with ulObjID set to one of the 32 object buffers

If you specify a message object buffer that already contains a message definition, it will be overwritten.

Returns:

None.

4.2.5.16 CANReadDataReg

This function copies data from a buffer to the CAN Data registers.

Prototype:

void

CANReadDataReg(unsigned char *pucData, unsigned long *pulRegister, int iSize)

Parameters:

pucData is a pointer to location to store the data read from the CAN controller’s data registers.

46 October 11, 2007


pulRegister is an unsigned long pointer to the first register of the CAN controller’s data registers. For example in order to use the IF1 register set on CAN controller 1 the value would be: (CAN0_BASE + CAN_O_IF1DA1).

iSize is the number of bytes to copy from the CAN controller.

Description:

This function takes the steps necessary to copy data to a contiguous buffer in memory from the non-contiguous data registers used by the CAN controller. This function is rarely used outside of the

CANMessageGet()

function.

Returns:

None.

4.2.5.17 CANReadReg

Reads a CAN controller register.

Prototype:

unsigned long

CANReadReg(unsigned long ulRegAddress)

Parameters:

ulRegAddress is the full address of the CAN register to be read.

Description:

This function takes care of the synchronization necessary to read from a CAN controller register.

Note:

This function takes care of delay required to access CAN registers. This delay is required when accessing CAN registers directly.

Returns:

The current value of the register that was requested by ulRegAddress.

4.2.5.18 CANRetryGet

Returns the current setting for auto-retransmission.

Prototype:

tBoolean

CANRetryGet(unsigned long ulBase)

Parameters:


Description:

Reads the current setting of the auto-retransmission setting in the CAN controller and returns it to the caller.

Returns:

true if automatic retransmission is enabled, false otherwise.

October 11, 2007 47


4.2.5.19 CANRetrySet

Sets the CAN controller auto-retransmission behavior.

Prototype:

void

CANRetrySet(unsigned long ulBase, tBoolean bAutoRetry)

Parameters:


bAutoRetry enables auto-retransmission

Description:

Enables or disables automatic retransmission of messages with detected errors. If bAutoRetry is true, then auto-retransmission is enabled, otherwise it is disabled.

Returns:

None.

4.2.5.20 CANSetBitTiming

Configures the CAN controller bit timing.

Prototype:

void

CANSetBitTiming(unsigned long ulBase,

tCANBitClkParms

*pClkParms)

Parameters:


pClkParms points to the structure with the clock parameters

Description:

Configures the various timing parameters for the CAN bus bit timing: Propagation segment,

Phase Buffer 1 segment, Phase Buffer 2 segment, and the Synchronization Jump Width. The values for Propagation and Phase Buffer 1 segments are derived from the combination parameter pClkParms->uSyncPropPhase1Seg. Phase Buffer 2 is determined from the parameter pClkParms->uPhase2Seg. These two parameters, along with pClkParms->uSJW are based in units of bit time quanta. The actual quantum time is determined by the pClkParms->u-

QuantumPrescaler value, which specifies what the divisor for the CAN module clock.

The total bit time, in quanta, will be the sum of the two Seg parameters, as follows: bit_time_q = uSyncPropPhase1Seg + uPhase2Seg + 1

Note that the Sync_Seg is always one quantum in duration, and will be added to derive the correct duration of Prop_Seg and Phase1_Seg.

The equation to determine the actual bit rate is as follows:

CAN Clock / ((uSyncPropPhase1Seg + uPhase2Seg + 1)∗(uQuantumPrescaler ))

This means that with uSyncPropPhase1Seg = 4, uPhase2Seg = 1, uQuantumPrescaler = 2 and a 8MHz CAN clock, that the bit rate will be (8MHz)/((5 + 2 + 1)∗2) or 500 KBit/sec.

48 October 11, 2007


Returns:

None.

4.2.5.21 CANStatusGet

Reads one of the controller status registers.

Prototype:

unsigned long

CANStatusGet(unsigned long ulBase,

tCANStsReg

eStatusReg)

Parameters:


eStatusReg is the status register to read

Description:

Reads a status register of the CAN controller and returns it to the caller. The different status registers are:

CAN_STS_CONTROL - the main controller status

CAN_STS_TXREQUEST - bit mask of objects pending transmission

CAN_STS_NEWDAT - bit mask of objects with new data

CAN_STS_MSGVAL - bit mask of objects with valid configuration

When reading the main controller status register, a pending status interrupt will be cleared.

This should be used in the interrupt handler for the CAN controller if the cause is a status interrupt. The fields of controller status register are as follows:

CAN_STS_BOFF - controller is in bus-off condition

CAN_STS_EWARN - an error counter has reached a limit of at least 96

CAN_STS_EPASS - CAN controller is in the error passive state

CAN_STS_RXOK - a message was received successfully (independent of any message filtering.

CAN_STS_TXOK - a message was successfully transmitted

CAN_STS_LEC_MSK - mask of last error code bits (3 bits)

CAN_STS_LEC_NONE - no error

CAN_STS_LEC_STUFF - stuffing error detected

CAN_STS_LEC_FORM - a format error in the fixed format part of a message

CAN_STS_LEC_ACK - a transmitted message was not acknowledged

CAN_STS_LEC_BIT1 - dominant level detected when trying to send recessive

CAN_STS_LEC_BIT0 - recessive level detected when trying to send dominant

CAN_STS_LEC_CRC - CRC error in received message

The remaining status registers are 32-bit bit maps to the message objects. They can be used to quickly obtain information about the status of all the message object without needing to query each one. They contain the following information:

CAN_STS_TXREQUEST - if a message object’s TxRequest bit is set, that means that a transmission is pending on that object. The application can use this to determine which objects are still waiting to send a message.

October 11, 2007 49


CAN_STS_NEWDAT - if a message object’s NewDat bit is set, that means that a new message has been received in that object, and has not yet been picked up by the host application

CAN_STS_MSGVAL - if a message object’s MsgVal bit is set, that means it has a valid configuration programmed. The host application can use this to determine which message objects are empty/unused.

Returns:

The value of the status register.

4.2.5.22 CANWriteDataReg

This function copies data from a buffer to the CAN Data registers.

Prototype:

void

CANWriteDataReg(unsigned char *pucData, unsigned long *pulRegister, int iSize)

Parameters:

pucData is a pointer to the data to be written out to the CAN controller’s data registers.

pulRegister is an unsigned long pointer to the first register of the CAN controller’s data registers. For example in order to use the IF1 register set on CAN controller 0 the value would be: (CAN0_BASE + CAN_O_IF1DA1).

iSize is the number of bytes to copy into the CAN controller.

Description:

This function takes the steps necessary to copy data from a contiguous buffer in memory into the non-contiguous data registers used by the CAN controller. This function is rarely used outside of the

CANMessageSet()

function.

Returns:

None.

4.2.5.23 CANWriteReg

Writes a CAN controller register.

Prototype:

void

CANWriteReg(unsigned long ulRegAddress, unsigned long ulRegValue)

Parameters:

ulRegAddress is the full address of the CAN register to be written.

ulRegValue is the value to write into the register specified by ulRegAddress.

Description:

This function takes care of the synchronization necessary to write to a CAN controller register.

50 October 11, 2007


Note:

The delays in this function are required when accessing CAN registers directly.

Returns:

None.

4.3


This example code will send out data from CAN controller 0 to be received by CAN controller 1. In order to actually receive the data an external cable must be connected between the two ports. In this example both controllers are configured for 1Mbit operation.

tCANBitClkParms CANBitClk; tCANMsgObject MsgObjectRx; tCANMsgObject MsgObjectTx; unsigned char ucBufferIn[8]; unsigned char ucBufferOut[8];

//

// Reset the state of all the message objects and the state of the CAN

// module to a known state.

//

CANInit(CAN0_BASE);

CANInit(CAN1_BASE);

//

// Configure the controller for 1Mbit operation.

//

CANBitClk.uSyncPropPhase1Seg = 5;

CANBitClk.uPhase2Seg = 2;

CANBitClk.uQuantumPrescaler = 1;

CANBitClk.uSJW = 2;

CANSetBitTiming(CAN0_BASE, &CANBitClk);

CANSetBitTiming(CAN1_BASE, &CANBitClk);

//

// Take the CAN0 device out of INIT state.

//

CANEnable(CAN0_BASE);

CANEnable(CAN1_BASE);

//

// Configure a receive object.

//

MsgObjectRx.ulMsgID = (0x400);

MsgObjectRx.ulMsgIDMask = 0x7f8;

MsgObjectRx.ulFlags = MSG_OBJ_USE_ID_FILTER;

MsgObjectRx.ulMsgLen = 8;

MsgObjectRx.pucMsgData = ucBufferIn;

CANMessageSet(CAN1_BASE, 1, &MsgObjectRx, MSG_OBJ_TYPE_RX);

//

// Configure and start transmit of message object.

//

MsgObjectTx.ulMsgID = 0x400;

MsgObjectTx.ulFlags = 0;

MsgObjectTx.ulMsgLen = 8;

MsgObjectTx.pucMsgData = ucBufferOut;

CANMessageSet(CAN0_BASE, 2, &MsgObjectTx, MSG_OBJ_TYPE_TX);

//

October 11, 2007 51


// Wait for new data to become available.

// while((CANStatusGet(CAN1_BASE, CAN_STS_NEWDAT) & 1) == 0)

{

//

// Read the message out of the message object.

//

CANMessageGet(CAN1_BASE, 1, &MsgObjectRx, true);

}

//

// Process new data in MsgObjectRx.pucMsgData.

//

...

52 October 11, 2007

5


Ethernet Controller

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51


5.1

Introduction

The Stellaris Ethernet controller consists of a fully integrated media access controller (MAC) and a network physical (PHY) interface device. The Ethernet controller conforms to IEEE 802.3 specifications and fully supports 10BASE-T and 100BASE-TX standards.

The Ethernet API provides the set of functions required to implement an interrupt driven Ethernet driver for this Ethernet controller. Functions are provided to configure and control the MAC, to access the register set on the PHY, to transmit and receive Ethernet packets, and to configure and control the interrupts that are available.

5.2

API Functions

Functions unsigned long

EthernetConfigGet


EthernetConfigSet

(unsigned long ulBase, unsigned long ulConfig) void

EthernetDisable


EthernetEnable


EthernetInitExpClk

(unsigned long ulBase, unsigned long ulEthClk) void

EthernetIntClear


EthernetIntDisable


EthernetIntEnable


EthernetIntRegister


EthernetIntStatus

(unsigned long ulBase, tBoolean bMasked) void

EthernetIntUnregister


EthernetMACAddrGet

(unsigned long ulBase, unsigned char ∗pucMACAddr) void

EthernetMACAddrSet

(unsigned long ulBase, unsigned char ∗pucMACAddr) tBoolean

EthernetPacketAvail

(unsigned long ulBase) long

EthernetPacketGet

(unsigned long ulBase, unsigned char ∗pucBuf, long lBufLen) long

EthernetPacketGetNonBlocking

(unsigned long ulBase, unsigned char ∗pucBuf, long l-

BufLen) long

EthernetPacketPut

(unsigned long ulBase, unsigned char ∗pucBuf, long lBufLen) long

EthernetPacketPutNonBlocking

(unsigned long ulBase, unsigned char ∗pucBuf, long l-

BufLen) unsigned long

EthernetPHYRead

(unsigned long ulBase, unsigned char ucRegAddr) void

EthernetPHYWrite

(unsigned long ulBase, unsigned char ucRegAddr, unsigned long ul-

Data) tBoolean

EthernetSpaceAvail

(unsigned long ulBase)

October 11, 2007 53

Ethernet Controller

5.2.1


For any application, the

EthernetInitExpClk()

function must be called first to prepare the Ethernet controller for operation. This function will configure the Ethernet controller options that are based on System parameters, such as the System Clock speed.

Once initialized, access to the PHY is available via the

EthernetPHYRead()

and

Ethernet-

PHYWrite()

functions. By default, the PHY will auto-negotiate the line speed and duplex modes.

For most applications, this will be sufficient. If a special configuration is required, the PHY read and write functions can be used to reconfigure the PHY to the desired mode of operation.

The MAC must also be configured using the

EthernetConfigSet()

function. The parameters for this function will allow the configuration of options such as Promiscuous Mode, Multicast Reception,

Transmit Data Length Padding, etc. The

EthernetConfigGet()

function can be used to query the current configuration of the Ethernet MAC.

The MAC address, used for incoming packet filtering, must also be programmed using the

Ethernet-

MACAddrSet()

function. The current value can be queried using the

EthernetMACAddrGet()

function.

When configuration has been completed, the Ethernet controller can be enabled using the

Ethernet-

Enable()

function. When getting ready to terminate operations on the Ethernet controller, the

EthernetDisable()

function may be called.

After the Ethernet controller has been enabled, Ethernet frames can be transmitted and received using the

EthernetPacketPut()

and

EthernetPacketGet()

functions. Care must be taken when using these functions, as they are blocking functions, and will not return until data is available (for RX) or buffer space is available (for TX). The

EthernetSpaceAvail()

and

EthernetPacketAvail()

functions can be called to determine if there is room for a TX packet or if there is an RX packet available prior to calling these blocking functions. Alternatively, the

EthernetPacketGetNonBlocking()

and

EthernetPacketPutNonBlocking()

functions will return immediately if a packet cannot be processed.

Otherwise, the packet will be processed normally.

When developing a mapping layer for a TCP/IP stack, you may wish to use the interrupt capability of the Ethernet controller. The

EthernetIntRegister()

and

EthernetIntUnregister()

functions are used to register an ISR with the system and to enable or disable the Ethernet controller’s interrupt signal.

The

EthernetIntEnable()

and

EthernetIntDisable()

functions are used to manipulate the individual interrupt sources available in the Ethernet controller (e.g. RX Error, TX Complete). The

EthernetInt-

Status()

and

EthernetIntClear()

functions would be used to query the active interrupts to determine which process to service, and to clear the indicated interrupts prior to returning from the registered

ISR.

The EthernetInit(), EthernetPacketNonBlockingGet(), and EthernetPacketNonBlockingPut() APIs from previous versions of the Peripheral Driver Library have been replaced by the

EthernetInitExp-

Clk() ,

EthernetPacketGetNonBlocking() , and

EthernetPacketPutNonBlocking()

APIs, respectively.

Macro have been provided in ethernet.h to map the old APIs to the new APIs, allowing existing applications to link and run with the new APIs. It is recommended that new applications utilize the new APIs in favor of the old ones.

5.2.2


5.2.2.1

EthernetConfigGet

Gets the current configuration of the Ethernet Controller.

54 October 11, 2007


Prototype:

unsigned long

EthernetConfigGet(unsigned long ulBase)

Parameters:


Description:

This function will query the control registers of the Ethernet Controller and return a bit-mapped configuration value.

See also:

The description of the

EthernetConfigSet()

function provides detailed information for the bitmapped configuration values that will be returned.

Returns:

The bit-mapped Ethernet Controller configuration value.

5.2.2.2

EthernetConfigSet

Sets the configuration of the Ethernet Controller.

Prototype:

void

EthernetConfigSet(unsigned long ulBase, unsigned long ulConfig)

Parameters:


ulConfig is the configuration for the controller.

Description:

After the EthernetInit function has been called, this API function can be used to configure the various features of the Ethernet Controller.

The Ethernet Controller provides three control registers that are used to configure the controller’s operation. The transmit control register provides settings to enable full duplex operation, to auto-generate the frame check sequence, and to pad the transmit packets to the minimum length as required by the IEEE standard. The receive control register provides settings to enable reception of packets with bad frame check sequence values and to enable multi-cast or promiscuous modes. The time stamp control register provides settings that enable support logic in the controller that allow the use of the General Purpose Timer 3 to capture time stamps for the transmitted and received packets.

The parameter ulConfig is the logic OR of the following values.

ETH_CFG_TS_TSEN - Enable TX and RX interrupt status as CCP timer inputs

ETH_CFG_RX_BADCRCDIS - Disable reception of packets with a bad CRC

ETH_CFG_RX_PRMSEN - Enable promiscuous mode reception (all packets)

ETH_CFG_RX_AMULEN - Enable reception of multicast packets

ETH_CFG_TX_DPLXEN - Enable full duplex transmit mode

ETH_CFG_TX_CRCEN - Enable transmit with auto CRC generation

ETH_CFG_TX_PADEN - Enable padding of transmit data to minimum size

October 11, 2007 55

Ethernet Controller

These bit-mapped values are programmed into the transmit, receive and/or time stamp control register.

Returns:

None.

5.2.2.3

EthernetDisable

Disables the Ethernet Controller.

Prototype:

void

EthernetDisable(unsigned long ulBase)

Parameters:


Description:

When terminating operations on the Ethernet interface, this function should be called. This function will disable the transmitter and receiver, and will clear out the receive FIFO.

Returns:

None.

5.2.2.4

EthernetEnable

Enables the Ethernet Controller for normal operation.

Prototype:

void

EthernetEnable(unsigned long ulBase)

Parameters:


Description:

Once the Ethernet Controller has been configured using the EthernetConfigSet function and the MAC address has been programmed using the EthernetMACAddrSet function, this API function can be called to enable the controller for normal operation.

This function will enable the controller’s transmitter and receiver, and will reset the receive

FIFO.

Returns:

None.

5.2.2.5

EthernetInitExpClk

Initializes the Ethernet Controller for operation.

56 October 11, 2007


Prototype:

void

EthernetInitExpClk(unsigned long ulBase, unsigned long ulEthClk)

Parameters:


ulEthClk is the rate of the clock supplied to the Ethernet module.

Description:

This function will prepare the Ethernet Controller for first time use in a given hardware/software configuration. This function should be called before any other Ethernet API functions are called.

The peripheral clock will be the same as the processor clock. This will be the value returned by

SysCtlClockGet() , or it can be explicitly hard coded if it is constant and known (to save the

code/execution overhead of a call to

SysCtlClockGet() ).

This function replaces the original EthernetInit() API and performs the same actions. A macro is provided in ethernet.h to map the original API to this API.

Note:

If the device configuration is changed (e.g. the System Clock is reprogrammed to a different speed), then the Ethernet Controller must be disabled by calling the EthernetDisable function and the controller must be reinitialized by calling the EthernetInit function again. After the controller has been reinitialized, the controller should be reconfigured using the appropriate

Ethernet API calls.

Returns:

None.

5.2.2.6

EthernetIntClear

Clears Ethernet interrupt sources.

Prototype:

void

EthernetIntClear(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:


ulIntFlags is a bit mask of the interrupt sources to be cleared.

Description:

The specified Ethernet interrupt sources are cleared, so that they no longer assert. This must be done in the interrupt handler to keep it from being called again immediately upon exit.

The parameter ulIntFlags has the same definition as the same parameter to

EthernetInt-

Enable() .

Returns:

None.

October 11, 2007 57

Ethernet Controller

5.2.2.7

EthernetIntDisable

Disables individual Ethernet interrupt sources.

Prototype:

void

EthernetIntDisable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

Disables the indicated Ethernet interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.


EthernetInt-

Enable() .

Returns:

None.

5.2.2.8

EthernetIntEnable

Enables individual Ethernet interrupt sources.

Prototype:

void

EthernetIntEnable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

Enables the indicated Ethernet interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.


ETH_INT_PHY - An interrupt from the PHY has occurred. The integrated PHY supports a number of interrupt conditions. The PHY register, PHY_MR17, must be read to determine which PHY interrupt has occurred. This register can be read using the

EthernetPHYRead()

API function.

ETH_INT_MDIO - This interrupt indicates that a transaction on the management interface has completed successfully.

ETH_INT_RXER - This interrupt indicates that an error has occurred during reception of a frame. This error can indicated a length mismatch, a CRC failure, or an error indication from the PHY.

ETH_INT_RXOF - This interrupt indicates that a frame has been received that exceeds the available space in the RX FIFO.

58 October 11, 2007


ETH_INT_TX - This interrupt indicates that the packet stored in the TX FIFO has been successfully transmitted.

ETH_INT_TXER - This interrupt indicates that an error has occurred during the transmission of a packet. This error can be either a retry failure during the backoff process, or an invalid length stored in the TX FIFO.

ETH_INT_RX - This interrupt indicates that one (or more) packets are available in the RX

FIFO for processing.

Returns:

None.

5.2.2.9

EthernetIntRegister

Registers an interrupt handler for an Ethernet interrupt.

Prototype:

void

EthernetIntRegister(unsigned long ulBase, void (*pfnHandler)(void))

Parameters:


pfnHandler is a pointer to the function to be called when the enabled Ethernet interrupts occur.

Description:

This function does the actual registering of the interrupt handler. This will enable the global interrupt in the interrupt controller; specific Ethernet interrupts must be enabled via

Ethernet-

IntEnable() . It is the interrupt handler’s responsibility to clear the interrupt source.

See also:

IntRegister()


Returns:

None.

5.2.2.10 EthernetIntStatus

Gets the current Ethernet interrupt status.

Prototype:

unsigned long

EthernetIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:



October 11, 2007 59

Ethernet Controller

Description:

This returns the interrupt status for the Ethernet Controller. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:

The current interrupt status, enumerated as a bit field of values described in

EthernetInt-

Enable() .

5.2.2.11 EthernetIntUnregister

Unregisters an interrupt handler for an Ethernet interrupt.

Prototype:

void

EthernetIntUnregister(unsigned long ulBase)

Parameters:


Description:

This function does the actual unregistering of the interrupt handler. It will clear the handler to be called when an Ethernet interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

See also:

IntRegister()


Returns:

None.

5.2.2.12 EthernetMACAddrGet

Gets the MAC Address of the Ethernet Controller.

Prototype:

void

EthernetMACAddrGet(unsigned long ulBase, unsigned char *pucMACAddr)

Parameters:


pucMACAddr is the pointer to the location in which to store the array of MAC-48 Address

Octets.

Description:

This function will read the currently programed MAC address into the pucMACAddr buffer.

See also:

Refer to EthernetMACSet API description for more details about the MAC address format.

Returns:

None.

60 October 11, 2007


5.2.2.13 EthernetMACAddrSet

Sets the MAC address of the Ethernet Controller.

Prototype:

void

EthernetMACAddrSet(unsigned long ulBase, unsigned char *pucMACAddr)

Parameters:


pucMACAddr is the pointer to the array of MAC-48 address octets.

Description:

This function will program the IEEE defined MAC-48 address specified in pucMACAddr into the

Ethernet Controller. This address is used by the Ethernet Controller for hardware level filtering of incoming Ethernet packets (when promiscuous mode is not enabled).

The MAC-48 address is defined as 6 octets, illustrated by the fictitious address below. The numbers are presented in hexadecimal format.

AC-DE-48-00-00-80

In this representation, the first three octets (AC-DE-48) are the Organizationally Unique Identifier (OUI). This is a number assigned by the IEEE to an organization that requests a block of MAC addresses. The last three octets are a 24-bit number managed by the OUI owner to uniquely identify a piece of hardware within that organization that is to be connected to the

Ethernet.

In this representation, the octets are transmitted from left to right, with the "AC" octet being transmitted first and the "80" octet being transmitted last. Within an octet, the bits are transmitted LSB to MSB. For this address, the first bit to be transmitted would be "0", the LSB of "AC", and the last bit to be transmitted would be "1", the MSB of "80".

Returns:

None.

5.2.2.14 EthernetPacketAvail

Check for packet available from the Ethernet Controller.

Prototype:

tBoolean

EthernetPacketAvail(unsigned long ulBase)

Parameters:


Description:

The Ethernet Controller provides a register that contains the number of packets available in the receive FIFO. When the last bytes of a packet successfully received (i.e. the frame check sequence bytes), the packet count is incremented. Once the packet has been fully read (including the frame check sequence bytes) from the FIFO, the packet count will be decremented.

October 11, 2007 61

Ethernet Controller

Returns:

This function will return true if there are one or more packets available in the receive FIFO, including the current packet being read. Otherwise, this function will return false.

5.2.2.15 EthernetPacketGet

Waits for a packet from the Ethernet Controller.

Prototype:

long

EthernetPacketGet(unsigned long ulBase, unsigned char *pucBuf, long lBufLen)

Parameters:


pucBuf is the pointer to the packet buffer.

lBufLen is the maximum number of bytes to be read into the buffer.

Description:

This function reads a packet from the receive FIFO of the controller and places it into pucBuf .

The function will wait until a packet is available in the FIFO. Then the function will read the entire packet from the receive FIFO. If there are more bytes in the packet than will fit into puc-

Buf (as specified by lBufLen), the function will return the negated length of the packet and the buffer will contain lBuflen bytes of the packet. Otherwise, the function will return the length of the packet that was read and pucBuf will contain the entire packet (excluding the frame check sequence bytes).

Note:

This function is blocking, and will not return until a packet arrives.

Returns:

If the packet is too large for pucBuf , the function will return the negated length -n. Otherwise, the function will return the length n of the received packet.

5.2.2.16 EthernetPacketGetNonBlocking

Receives a packet from the Ethernet Controller.

Prototype:

long

EthernetPacketGetNonBlocking(unsigned long ulBase, unsigned char *pucBuf, long lBufLen)

Parameters:



lBufLen is the maximum number of bytes to be read into the buffer.

62 October 11, 2007


Description:

This function reads a packet from the receive FIFO of the controller and places it into pucBuf .

If no packet is available the function will return immediately. Otherwise the function will read the entire packet from the receive FIFO. If there are more bytes in the packet than will fit into pucBuf (as specified by lBufLen), the function will return the negated length of the packet and the buffer will contain lBufLen bytes of the packet. Otherwise, the function will return the length of the packet that was read and pucBuf will contain the entire packet (excluding the frame check sequence bytes).

This function replaces the original EthernetPacketNonBlockingGet() API and performs the same actions. A macro is provided in ethernet.h to map the original API to this API.

Note:

This function will return immediately if no packet is available.

Returns:

This function will return 0 if no packet is available. If the packet is too large for pucBuf , the function will return the negated length -n. Otherwise, the function will return the length n of the received packet.

5.2.2.17 EthernetPacketPut

Waits to send a packet from the Ethernet Controller.

Prototype:

long

EthernetPacketPut(unsigned long ulBase, unsigned char *pucBuf, long lBufLen)

Parameters:



lBufLen is number of bytes in the packet to be transmitted.

Description:

This function writes lBufLen bytes of the packet contained in pucBuf into the transmit FIFO of the controller and then activates the transmitter for this packet. This function will wait until the transmit FIFO is empty. Once space is available, the function will return once lBufLen bytes of the packet have been placed into the FIFO and the transmitter has been started. The function will not wait for the transmission to complete. The function will return the negated lBuflen if the length is larger than the space available in the transmit FIFO.

Note:

This function blocks, and will wait until space is available for the transmit packet before returning.

Returns:

If the packet is too large for FIFO, the function will return the negated length -lBufLen. Otherwise, the function will return the length lBufLen of the transmitted packet.

October 11, 2007 63

Ethernet Controller

5.2.2.18 EthernetPacketPutNonBlocking

Sends a packet to the Ethernet Controller.

Prototype:

long

EthernetPacketPutNonBlocking(unsigned long ulBase, unsigned char *pucBuf, long lBufLen)

Parameters:



lBufLen is number of bytes in the packet to be transmitted.

Description:

This function writes lBufLen bytes of the packet contained in pucBuf into the transmit FIFO of the controller and then activates the transmitter for this packet. If no space is available in the FIFO, the function will return immediately. If space is available, the function will return once lBufLen bytes of the packet have been placed into the FIFO and the transmitter has been started. The function will not wait for the transmission to complete. The function will return the negated lBuflen if the length is larger than the space available in the transmit FIFO.

This function replaces the original EthernetPacketNonBlockingPut() API and performs the same actions. A macro is provided in ethernet.h to map the original API to this API.

Note:

This function does not block, and will return immediately if no space is available for the transmit packet.

Returns:

This function will return 0 if no space is available in the transmit FIFO. If the packet is too large for FIFO, the function will return the negated length -lBufLen. Otherwise, the function will return the length lBufLen of the transmitted packet.

5.2.2.19 EthernetPHYRead

Read from a PHY register.

Prototype:

unsigned long

EthernetPHYRead(unsigned long ulBase, unsigned char ucRegAddr)

Parameters:


ucRegAddr is the address of the PHY register to be accessed.

Description:

This function will the contents of the PHY register specified by ucRegAddr .

Returns:

The function will return the 16-bit value read from the PHY.

64 October 11, 2007


5.2.2.20 EthernetPHYWrite

Write to the PHY register.

Prototype:

void

EthernetPHYWrite(unsigned long ulBase, unsigned char ucRegAddr, unsigned long ulData)

Parameters:


ucRegAddr is the address of the PHY register to be accessed.

ulData is the data to be written to the PHY register.

Description:

This function will write the ulData to the PHY register specified by ucRegAddr .

Returns:

None.

5.2.2.21 EthernetSpaceAvail

Check for packet space available in the Ethernet Controller.

Prototype:

tBoolean

EthernetSpaceAvail(unsigned long ulBase)

Parameters:


Description:

The Ethernet Controller’s transmit FIFO is designed to support a single packet at a time. After the packet has been written into the FIFO, the transmit request bit must be set to enable the transmission of the packet. Only after the packet has been transmitted can a new packet be written into the FIFO. This function will simply check to see if a packet is in progress. If so, there is no space available in the transmit FIFO.

Returns:

This function will return true if a space is available in the transmit FIFO, otherwise, will return

false.

5.3


The following example shows how to use the this API to initialize the Ethernet controller to transmit and receive packets.

October 11, 2007 65

Ethernet Controller unsigned char pucMACAddress[6]; unsigned char pucMyRxPacket[]; unsigned char pucMyTxPacket[]; unsigned long ulMyTxPacketLength;

//

// Initialize the Ethernet controller for operation

//

EthernetInitExpClk(ETH_BASE, SysCtlClockGet());

//

// Configure the Ethernet controller for normal operation

// Enable TX Duplex Mode

// Enable TX Padding

//

EthernetConfigSet(ETH_BASE, (ETH_CFG_TX_DPLXEN | ETH_CFG_TX_PADEN));

//

// Program the MAC Address (01-23-45-67-89-AB)

// pucMACAddress[0] = 0x01; pucMACAddress[1] = 0x23; pucMACAddress[2] = 0x45; pucMACAddress[3] = 0x67; pucMACAddress[4] = 0x89; pucMACAddress[5] = 0xAB;

EthernetMACAddrSet(ETH_BASE, pucMACAddress);

//

// Enable the Ethernet controller

//

EthernetEnable(ETH_BASE);

//

// Send a packet.

// (assume that the packet has been filled in appropriately elsewhere

// in the code).

//

EthernetPacketPut(ETH_BASE, pucMyTXPacket, ulMyTxPacketLength);

//

// Wait for a packet to come in.

//

EthernetPacketGet(ETH_BASE, pucMyRXPacket, sizeof(pucMyRxPacket));

66 October 11, 2007

6


Flash

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65


6.1

Introduction

The flash API provides a set of functions for dealing with the on-chip flash. Functions are provided to program and erase the flash, configure the flash protection, and handle the flash interrupt.

The flash is organized as a set of 1 kB blocks that can be individually erased. Erasing a block causes the entire contents of the block to be reset to all ones. 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 differing 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 processor instruction fetch mechanism, protecting the contents of those blocks from being read by either the processor or by debuggers.

The flash can be programmed on a word-by-word basis. Programming causes 1 bits to become 0 bits (where appropriate); because of this, a word can be repeatedly programmed so long as each programming operation only requires changing 1 bits to 0 bits.

The timing for the flash is automatically handled by the flash controller. In order to do this, the flash controller must know the clock rate of the system in order to be able to time the number of micro-seconds certain signals are asserted. The number of clock cycles per micro-second must be provided to the flash controller for it to accomplish this timing.

The flash controller has the ability to generate an interrupt when an invalid access is attempted

(such as reading from execute-only flash). This can be used to validate the operation of a program; the interrupt will keep invalid accesses from being silently ignored, hiding potential bugs. The flash protection can be applied without being permanently enabled; this, along with the interrupt, allows the program to be debugged before the flash protection is permanently applied to the device (which is a non-reversible operation). An interrupt can also be generated when an erase or programming operation has completed.

Depending upon the member of the Stellaris family used, the amount of available flash is 8 KB, 16

KB, 32 KB, 64 KB, 96 KB, 128 KB, or 256 KB.

6.2

API Functions

Functions long

FlashErase

(unsigned long ulAddress) void

FlashIntClear

(unsigned long ulIntFlags) void

FlashIntDisable


FlashIntEnable

(unsigned long ulIntFlags) unsigned long

FlashIntGetStatus

(tBoolean bMasked) void

FlashIntRegister

(void (∗pfnHandler)(void))

October 11, 2007 67

Flash void

FlashIntUnregister

(void) long

FlashProgram

(unsigned long ∗pulData, unsigned long ulAddress, unsigned long ul-

Count) tFlashProtection

FlashProtectGet

(unsigned long ulAddress) long

FlashProtectSave

(void) long

FlashProtectSet

(unsigned long ulAddress, tFlashProtection eProtect) unsigned long

FlashUsecGet

(void) void

FlashUsecSet

(unsigned long ulClocks) long

FlashUserGet

(unsigned long ∗pulUser0, unsigned long ∗pulUser1) long

FlashUserSave

(void) long

FlashUserSet

(unsigned long ulUser0, unsigned long ulUser1)

6.2.1


The flash API is broken into three groups of functions: those that deal with programming the flash, those that deal with flash protection, and those that deal with interrupt handling.

Flash programming is managed with

FlashErase() ,

FlashProgram() ,

FlashUsecGet() , and Flash-

UsecSet() .

Flash protection is managed with

FlashProtectGet() ,

FlashProtectSet() , and FlashProtectSave() .

Interrupt handling is managed with

FlashIntRegister() , FlashIntUnregister() ,

FlashIntEnable() ,

FlashIntDisable() ,

FlashIntGetStatus() , and

FlashIntClear() .

6.2.2


6.2.2.1

FlashErase

Erases a block of flash.

Prototype:

long

FlashErase(unsigned long ulAddress)

Parameters:

ulAddress is the start address of the flash block to be erased.

Description:

This function will erase a 1 kB block of the on-chip flash. After erasing, the block will be filled with 0xFF bytes. Read-only and execute-only blocks cannot be erased.

This function will not return until the block has been erased.

Returns:

Returns 0 on success, or -1 if an invalid block address was specified or the block is writeprotected.

68 October 11, 2007


6.2.2.2

FlashIntClear

Clears flash controller interrupt sources.

Prototype:

void

FlashIntClear(unsigned long ulIntFlags)

Parameters:

ulIntFlags is the bit mask of the interrupt sources to be cleared. Can be any of the FLASH_-

FCMISC_PROGRAM or FLASH_FCMISC_ACCESS values.

Description:

The specified flash controller interrupt sources are cleared, so that they no longer assert. This must be done in the interrupt handler to keep it from being called again immediately upon exit.

Returns:

None.

6.2.2.3

FlashIntDisable

Disables individual flash controller interrupt sources.

Prototype:

void

FlashIntDisable(unsigned long ulIntFlags)

Parameters:

ulIntFlags is a bit mask of the interrupt sources to be disabled. Can be any of the FLASH_-

FCIM_PROGRAM or FLASH_FCIM_ACCESS values.

Description:

Disables the indicated flash controller interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.

Returns:

None.

6.2.2.4

FlashIntEnable

Enables individual flash controller interrupt sources.

Prototype:

void

FlashIntEnable(unsigned long ulIntFlags)

Parameters:

ulIntFlags is a bit mask of the interrupt sources to be enabled. Can be any of the FLASH_-

FCIM_PROGRAM or FLASH_FCIM_ACCESS values.

October 11, 2007 69

Flash

Description:

Enables the indicated flash controller interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.

Returns:

None.

6.2.2.5

FlashIntGetStatus


Prototype:

unsigned long

FlashIntGetStatus(tBoolean bMasked)

Parameters:


Description:

This returns the interrupt status for the flash controller. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:

The current interrupt status, enumerated as a bit field of FLASH_FCMISC_PROGRAM and

FLASH_FCMISC_ACCESS.

6.2.2.6

FlashIntRegister

Registers an interrupt handler for the flash interrupt.

Prototype:

void

FlashIntRegister(void (*pfnHandler)(void))

Parameters:

pfnHandler is a pointer to the function to be called when the flash interrupt occurs.

Description:

This sets the handler to be called when the flash interrupt occurs. The flash controller can generate an interrupt when an invalid flash access occurs, such as trying to program or erase a read-only block, or trying to read from an execute-only block. It can also generate an interrupt when a program or erase operation has completed. The interrupt will be automatically enabled when the handler is registered.

See also:

IntRegister()


Returns:

None.

70 October 11, 2007


6.2.2.7

FlashIntUnregister

Unregisters the interrupt handler for the flash interrupt.

Prototype:

void

FlashIntUnregister(void)

Description:

This function will clear the handler to be called when the flash interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler is no longer called.

See also:

IntRegister()


Returns:

None.

6.2.2.8

FlashProgram

Programs flash.

Prototype:

long

FlashProgram(unsigned long *pulData, unsigned long ulAddress, unsigned long ulCount)

Parameters:

pulData is a pointer to the data to be programmed.

ulAddress is the starting address in flash to be programmed. Must be a multiple of four.

ulCount is the number of bytes to be programmed. Must be a multiple of four.

Description:

This function will program a sequence of words into the on-chip flash. Programming each location consists of the result of an AND operation of the new data and the existing data; in other words bits that contain 1 can remain 1 or be changed to 0, but bits that are 0 cannot be changed to 1. Therefore, a word can be programmed multiple times as long as these rules are followed; if a program operation attempts to change a 0 bit to a 1 bit, that bit will not have its value changed.

Since the flash is programmed one word at a time, the starting address and byte count must both be multiples of four. It is up to the caller to verify the programmed contents, if such verification is required.

This function will not return until the data has been programmed.

Returns:

Returns 0 on success, or -1 if a programming error is encountered.

October 11, 2007 71

Flash

6.2.2.9

FlashProtectGet

Gets the protection setting for a block of flash.

Prototype:

tFlashProtection

FlashProtectGet(unsigned long ulAddress)

Parameters:

ulAddress is the start address of the flash block to be queried.

Description:

This function will get the current protection for the specified 2 kB block of flash. Each block can be read/write, read-only, or execute-only. Read/write blocks can be read, executed, erased, and programmed. Read-only blocks can be read and executed. Execute-only blocks can only be executed; processor and debugger data reads are not allowed.

Returns:

Returns the protection setting for this block. See

FlashProtectSet()

for possible values.

6.2.2.10 FlashProtectSave

Saves the flash protection settings.

Prototype:

long

FlashProtectSave(void)

Description:

This function will make the currently programmed flash protection settings permanent. This is a non-reversible operation; a chip reset or power cycle will not change the flash protection.

This function will not return until the protection has been saved.

Returns:

Returns 0 on success, or -1 if a hardware error is encountered.

6.2.2.11 FlashProtectSet

Sets the protection setting for a block of flash.

Prototype:

long

FlashProtectSet(unsigned long ulAddress, tFlashProtection eProtect)

Parameters:

ulAddress is the start address of the flash block to be protected.

eProtect is the protection to be applied to the block. Can be one of FlashReadWrite, Flash-

ReadOnly, or FlashExecuteOnly.

72 October 11, 2007


Description:

This function will set the protection for the specified 2 kB block of flash. Blocks which are read/write can be made read-only or execute-only. Blocks which are read-only can be made execute-only. Blocks which are execute-only cannot have their protection modified. Attempts to make the block protection less stringent (i.e. read-only to read/write) will result in a failure

(and be prevented by the hardware).

Changes to the flash protection are maintained only until the next reset. This allows the application to be executed in the desired flash protection environment to check for inappropriate flash access (via the flash interrupt). To make the flash protection permanent, use the

Flash-

ProtectSave()

function.

Returns:

Returns 0 on success, or -1 if an invalid address or an invalid protection was specified.

6.2.2.12 FlashUsecGet

Gets the number of processor clocks per micro-second.

Prototype:

unsigned long

FlashUsecGet(void)

Description:

This function returns the number of clocks per micro-second, as presently known by the flash controller.

Returns:

Returns the number of processor clocks per micro-second.

6.2.2.13 FlashUsecSet

Sets the number of processor clocks per micro-second.

Prototype:

void

FlashUsecSet(unsigned long ulClocks)

Parameters:

ulClocks is the number of processor clocks per micro-second.

Description:

This function is used to tell the flash controller the number of processor clocks per microsecond. This value must be programmed correctly or the flash most likely will not program correctly; it has no affect on reading flash.

Returns:

None.

October 11, 2007 73

Flash

6.2.2.14 FlashUserGet

Gets the User Registers

Prototype:

long

FlashUserGet(unsigned long *pulUser0, unsigned long *pulUser1)

Parameters:

pulUser0 is a pointer to the location to store USER Register 0.

pulUser1 is a pointer to the location to store USER Register 1.

Description:

This function will read the contents of User Registers (0 and 1), and store them in the specified locations.

Returns:


6.2.2.15 FlashUserSave

Saves the User Registers

Prototype:

long

FlashUserSave(void)

Description:

This function will make the currently programmed User register settings permanent. This is a non-reversible operation; a chip reset or power cycle will not change this setting.

This function will not return until the protection has been saved.

Returns:


6.2.2.16 FlashUserSet

Sets the User Registers

Prototype:

long

FlashUserSet(unsigned long ulUser0, unsigned long ulUser1)

Parameters:

ulUser0 is the value to store in USER Register 0.

ulUser1 is the value to store in USER Register 1.

Description:

This function will set the contents of the User Registers (0 and 1) to the specified values.

74 October 11, 2007


Returns:


6.3


The following example shows how to use the flash API to erase a block of the flash and program a few words.

unsigned long pulData[2];

//

// Set the uSec value to 20, indicating that the processor is running at

// 20 MHz.

//

FlashUsecSet(20);

//

// Erase a block of the flash.

//

FlashErase(0x800);

//

// Program some data into the newly erased block of the flash.

// pulData[0] = 0x12345678; pulData[1] = 0x56789abc;

FlashProgram(pulData, 0x800, sizeof(pulData));

October 11, 2007 75

Flash

76 October 11, 2007

7


GPIO

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75


7.1

Introduction

The GPIO module provides control for up to eight independent GPIO pins (the actual number present depend upon the GPIO port and part number). Each pin has the following capabilities:

Can be configured as an input or an output. On reset, they default to being an input.

In input mode, can generate interrupts on high level, low level, rising edge, falling edge, or both edges.

In output mode, can be configured for 2 mA, 4 mA, or 8 mA drive strength. The 8 mA drive strength configuration has optional slew rate control to limit the rise and fall times of the signal.

On reset, they default to 2 mA drive strength.

Optional weak pull-up or pull-down resistors. On reset, they default to a weak pull-up.

Optional open-drain operation. On reset, they default to standard push/pull operation.

Can be configured to be a GPIO or a peripheral pin. On reset, they default to being GPIOs.

Note that not all pins on all parts have peripheral functions, in which case the pin is only useful as a GPIO (i.e. when configured for peripheral function the pin will not do anything useful).

Most of the GPIO functions can operate on more than one GPIO pin (within a single module) at a time. The ucPins parameter to these functions is used to specify the pins that are affected; the

GPIO pins whose corresponding bits in this parameter that are set will be affected (where pin 0 is in bit 0, pin 1 in bit 1, etc.). For example, if ucPins is 0x09, then pins 0 and 3 will be affected by the function.

This is most useful for the

GPIOPinRead()

and

GPIOPinWrite()

functions; a read will return only the value of the requested pins (with the other pin values masked out) and a write will affect the requested pins simultaneously (i.e. the state of multiple GPIO pins can be changed at the same time). This data masking for the GPIO pin state occurs in the hardware; a single read or write is issued to the hardware, which interprets some of the address bits as an indication of the GPIO pins to operate upon (and therefore the ones to not affect). See the part data sheet for details of the

GPIO data register address-based bit masking.

For functions that have a ucPin (singular) parameter, only a single pin is affected by the function. In this case, this value specifies the pin number (i.e. 0 through 7).

7.2

API Functions


GPIODirModeGet

(unsigned long ulPort, unsigned char ucPin) void

GPIODirModeSet

(unsigned long ulPort, unsigned char ucPins, unsigned long ulPinIO)

October 11, 2007 77

GPIO unsigned long

GPIOIntTypeGet

(unsigned long ulPort, unsigned char ucPin) void

GPIOIntTypeSet

(unsigned long ulPort, unsigned char ucPins, unsigned long ulIntType) void

GPIOPadConfigGet

(unsigned long ulPort, unsigned char ucPin, unsigned long ∗pul-

Strength, unsigned long ∗pulPinType) void

GPIOPadConfigSet

(unsigned long ulPort, unsigned char ucPins, unsigned long ul-

Strength, unsigned long ulPinType) void

GPIOPinIntClear

(unsigned long ulPort, unsigned char ucPins) void

GPIOPinIntDisable


GPIOPinIntEnable

(unsigned long ulPort, unsigned char ucPins) long

GPIOPinIntStatus

(unsigned long ulPort, tBoolean bMasked) long

GPIOPinRead


GPIOPinTypeCAN


GPIOPinTypeComparator


GPIOPinTypeGPIOInput


GPIOPinTypeGPIOOutput


GPIOPinTypeGPIOOutputOD


GPIOPinTypeI2C


GPIOPinTypePWM


GPIOPinTypeQEI


GPIOPinTypeSSI


GPIOPinTypeTimer


GPIOPinTypeUART


GPIOPinWrite

(unsigned long ulPort, unsigned char ucPins, unsigned char ucVal) void

GPIOPortIntRegister

(unsigned long ulPort, void (∗pfIntHandler)(void)) void

GPIOPortIntUnregister

(unsigned long ulPort)

7.2.1


The GPIO API is broken into three groups of functions: those that deal with configuring the GPIO pins, those that deal with interrupts, and those that access the pin value.

The GPIO pins are configured with

GPIODirModeSet()

and

GPIOPadConfigSet() . The configura-

tion can be read back with

GPIODirModeGet()

and

GPIOPadConfigGet() . There are also conve-

nience functions for configuring the pin in the required or recommended configuration for a particular peripheral; these are

GPIOPinTypeComparator() ,

GPIOPinTypeI2C() , GPIOPinTypePWM() ,

GPIOPinTypeQEI() ,

GPIOPinTypeSSI() , GPIOPinTypeTimer() , and

GPIOPinTypeUART() .

The GPIO interrupts are handled with

GPIOIntTypeSet() ,

GPIOIntTypeGet() ,

GPIOPinInt-

Enable() , GPIOPinIntDisable() ,

GPIOPinIntStatus() ,

GPIOPinIntClear() ,

GPIOPortIntRegister() ,

and

GPIOPortIntUnregister() .

The GPIO pin state is accessed with

GPIOPinRead()

and

GPIOPinWrite() .

7.2.2


7.2.2.1

GPIODirModeGet

Gets the direction and mode of a pin.

78 October 11, 2007


Prototype:

unsigned long

GPIODirModeGet(unsigned long ulPort, unsigned char ucPin)

Parameters:

ulPort is the base address of the GPIO port.

ucPin is the pin number.

Description:

This function gets the direction and control mode for a specified pin on the selected GPIO port.

The pin can be configured as either an input or output under software control, or it can be under hardware control. The type of control and direction are returned as an enumerated data type.

Returns:

Returns one of the enumerated data types described for

GPIODirModeSet() .

7.2.2.2

GPIODirModeSet

Sets the direction and mode of the specified pin(s).

Prototype:

void

GPIODirModeSet(unsigned long ulPort, unsigned char ucPins, unsigned long ulPinIO)

Parameters:

ulPort is the base address of the GPIO port

ucPins is the bit-packed representation of the pin(s).

ulPinIO is the pin direction and/or mode.

Description:

This function will set the specified pin(s) on the selected GPIO port as either an input or output under software control, or it will set the pin to be under hardware control.

The parameter ulPinIO is an enumerated data type that can be one of the following values:

GPIO_DIR_MODE_IN

GPIO_DIR_MODE_OUT

GPIO_DIR_MODE_HW

where GPIO_DIR_MODE_IN specifies that the pin will be programmed as a software controlled input, GPIO_DIR_MODE_OUT specifies that the pin will be programmed as a software controlled output, and GPIO_DIR_MODE_HW specifies that the pin will be placed under hardware control.

The pin(s) are specified using a bit-packed byte, where each bit that is set identifies the pin to be accessed, and where bit 0 of the byte represents GPIO port pin 0, bit 1 represents GPIO port pin 1, etc.

Returns:

None.

October 11, 2007 79

GPIO

7.2.2.3

GPIOIntTypeGet

Gets the interrupt type for a pin.

Prototype:

unsigned long

GPIOIntTypeGet(unsigned long ulPort, unsigned char ucPin)

Parameters:



Description:

This function gets the interrupt type for a specified pin on the selected GPIO port. The pin can be configured as a falling edge, rising edge, or both edge detected interrupt, or it can be configured as a low level or high level detected interrupt. The type of interrupt detection mechanism is returned as an enumerated data type.

Returns:

Returns one of the enumerated data types described for

GPIOIntTypeSet() .

7.2.2.4

GPIOIntTypeSet

Sets the interrupt type for the specified pin(s).

Prototype:

void

GPIOIntTypeSet(unsigned long ulPort, unsigned char ucPins, unsigned long ulIntType)

Parameters:



ulIntType specifies the type of interrupt trigger mechanism.

Description:

This function sets up the various interrupt trigger mechanisms for the specified pin(s) on the selected GPIO port.

The parameter ulIntType is an enumerated data type that can be one of the following values:

GPIO_FALLING_EDGE

GPIO_RISING_EDGE

GPIO_BOTH_EDGES

GPIO_LOW_LEVEL

GPIO_HIGH_LEVEL

where the different values describe the interrupt detection mechanism (edge or level) and the particular triggering event (falling, rising, or both edges for edge detect, low or high for level detect).

80 October 11, 2007



Note:

In order to avoid any spurious interrupts, the user must ensure that the GPIO inputs remain stable for the duration of this function.

Returns:

None.

7.2.2.5

GPIOPadConfigGet

Gets the pad configuration for a pin.

Prototype:

void

GPIOPadConfigGet(unsigned long ulPort, unsigned char ucPin, unsigned long *pulStrength, unsigned long *pulPinType)

Parameters:



pulStrength is a pointer to storage for the output drive strength.

pulPinType is a pointer to storage for the output drive type.

Description:

This function gets the pad configuration for a specified pin on the selected GPIO port. The values returned in eStrength and eOutType correspond to the values used in

GPIOPadConfig-

Set() . This function also works for pin(s) configured as input pin(s); however, the only mean-

ingful data returned is whether the pin is terminated with a pull-up or down resistor.

Returns:

None

7.2.2.6

GPIOPadConfigSet

Sets the pad configuration for the specified pin(s).

Prototype:

void

GPIOPadConfigSet(unsigned long ulPort, unsigned char ucPins, unsigned long ulStrength, unsigned long ulPinType)

Parameters:


October 11, 2007 81

GPIO


ulStrength specifies the output drive strength.

ulPinType specifies the pin type.

Description:

This function sets the drive strength and type for the specified pin(s) on the selected GPIO port. For pin(s) configured as input ports, the pad is configured as requested, but the only real effect on the input is the configuration of the pull-up or pull-down termination.

The parameter ulStrength can be one of the following values:

GPIO_STRENGTH_2MA



GPIO_STRENGTH_8MA_SC

where GPIO_STRENGTH_xMA specifies either 2, 4, or 8 mA output drive strength, and

GPIO_OUT_STRENGTH_8MA_SC specifies 8 mA output drive with slew control.

The parameter ulPinType can be one of the following values:

GPIO_PIN_TYPE_STD

GPIO_PIN_TYPE_STD_WPU

GPIO_PIN_TYPE_STD_WPD

GPIO_PIN_TYPE_OD

GPIO_PIN_TYPE_OD_WPU

GPIO_PIN_TYPE_OD_WPD

GPIO_PIN_TYPE_ANALOG

where GPIO_PIN_TYPE_STD∗ specifies a push-pull pin, GPIO_PIN_TYPE_OD∗ specifies an open-drain pin, ∗ _WPU specifies a weak pull-up, ∗_WPD specifies a weak pull-down, and

GPIO_PIN_TYPE_ANALOG specifies an analog input (for the comparators).


Returns:

None.

7.2.2.7

GPIOPinIntClear

Clears the interrupt for the specified pin(s).

Prototype:

void

GPIOPinIntClear(unsigned long ulPort, unsigned char ucPins)

Parameters:



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Description:

Clears the interrupt for the specified pin(s).


Returns:

None.

7.2.2.8

GPIOPinIntDisable

Disables interrupts for the specified pin(s).

Prototype:

void

GPIOPinIntDisable(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

Masks the interrupt for the specified pin(s).


Returns:

None.

7.2.2.9

GPIOPinIntEnable

Enables interrupts for the specified pin(s).

Prototype:

void

GPIOPinIntEnable(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

Unmasks the interrupt for the specified pin(s).


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GPIO

Returns:

None.

7.2.2.10 GPIOPinIntStatus

Gets interrupt status for the specified GPIO port.

Prototype:

long

GPIOPinIntStatus(unsigned long ulPort, tBoolean bMasked)

Parameters:


bMasked specifies whether masked or raw interrupt status is returned.

Description:

If bMasked is set as

true, then the masked interrupt status is returned; otherwise, the raw interrupt status will be returned.

Returns:

Returns a bit-packed byte, where each bit that is set identifies an active masked or raw interrupt, and where bit 0 of the byte represents GPIO port pin 0, bit 1 represents GPIO port pin 1, etc. Bits 31:8 should be ignored.

7.2.2.11 GPIOPinRead

Reads the values present of the specified pin(s).

Prototype:

long

GPIOPinRead(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The values at the specified pin(s) are read, as specified by ucPins. Values are returned for both input and output pin(s), and the value for pin(s) that are not specified by ucPins are set to

0.


Returns:

Returns a bit-packed byte providing the state of the specified pin, where bit 0 of the byte represents GPIO port pin 0, bit 1 represents GPIO port pin 1, etc. Any bit that is not specified by ucPins is returned as a 0. Bits 31:8 should be ignored.

84 October 11, 2007


7.2.2.12 GPIOPinTypeCAN

Configures pin(s) for use as a CAN device.

Prototype:

void

GPIOPinTypeCAN(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The CAN pins must be properly configured for the CAN peripherals to function correctly. This function provides a typical configuration for those pin(s); other configurations may work as well depending upon the board setup (for example, using the on-chip pull-ups).


Note:

This cannot be used to turn any pin into a CAN pin(s); it only configures a CAN pin(s) for proper operation.

Returns:

None.

7.2.2.13 GPIOPinTypeComparator

Configures pin(s) for use as an analog comparator input.

Prototype:

void

GPIOPinTypeComparator(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The analog comparator input pins must be properly configured for the analog comparator to function correctly. This function provides the proper configuration for those pin(s).


Note:

This cannot be used to turn any pin into an analog comparator input; it only configures an analog comparator pin for proper operation.

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GPIO

Returns:

None.

7.2.2.14 GPIOPinTypeGPIOInput

Configures pin(s) for use as GPIO inputs.

Prototype:

void

GPIOPinTypeGPIOInput(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The GPIO pins must be properly configured in order to function correctly as GPIO inputs; this is especially true of Fury-class devices where the digital input enable is turned off by default.

This function provides the proper configuration for those pin(s).


Returns:

None.

7.2.2.15 GPIOPinTypeGPIOOutput

Configures pin(s) for use as GPIO outputs.

Prototype:

void

GPIOPinTypeGPIOOutput(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The GPIO pins must be properly configured in order to function correctly as GPIO outputs; this is especially true of Fury-class devices where the digital input enable is turned off by default.



Returns:

None.

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7.2.2.16 GPIOPinTypeGPIOOutputOD

Configures pin(s) for use as GPIO open drain outputs.

Prototype:

void

GPIOPinTypeGPIOOutputOD(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The GPIO pins must be properly configured in order to function correctly as GPIO outputs; this is especially true of Fury-class devices where the digital input enable is turned off by default.



Returns:

None.

7.2.2.17 GPIOPinTypeI2C

Configures pin(s) for use by the I2C peripheral.

Prototype:

void

GPIOPinTypeI2C(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The I2C pins must be properly configured for the I2C peripheral to function correctly. This function provides the proper configuration for those pin(s).


Note:

This cannot be used to turn any pin into an I2C pin; it only configures an I2C pin for proper operation.

Returns:

None.

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GPIO

7.2.2.18 GPIOPinTypePWM

Configures pin(s) for use by the PWM peripheral.

Prototype:

void

GPIOPinTypePWM(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The PWM pins must be properly configured for the PWM peripheral to function correctly. This function provides a typical configuration for those pin(s); other configurations may work as well depending upon the board setup (for example, using the on-chip pull-ups).


Note:

This cannot be used to turn any pin into a PWM pin; it only configures a PWM pin for proper operation.

Returns:

None.

7.2.2.19 GPIOPinTypeQEI

Configures pin(s) for use by the QEI peripheral.

Prototype:

void

GPIOPinTypeQEI(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The QEI pins must be properly configured for the QEI peripheral to function correctly. This function provides a typical configuration for those pin(s); other configurations may work as well depending upon the board setup (for example, not using the on-chip pull-ups).


Note:

This cannot be used to turn any pin into a QEI pin; it only configures a QEI pin for proper operation.

88 October 11, 2007


Returns:

None.

7.2.2.20 GPIOPinTypeSSI

Configures pin(s) for use by the SSI peripheral.

Prototype:

void

GPIOPinTypeSSI(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The SSI pins must be properly configured for the SSI peripheral to function correctly. This function provides a typical configuration for those pin(s); other configurations may work as well depending upon the board setup (for example, using the on-chip pull-ups).


Note:

This cannot be used to turn any pin into a SSI pin; it only configures a SSI pin for proper operation.

Returns:

None.

7.2.2.21 GPIOPinTypeTimer

Configures pin(s) for use by the Timer peripheral.

Prototype:

void

GPIOPinTypeTimer(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The CCP pins must be properly configured for the timer peripheral to function correctly. This function provides a typical configuration for those pin(s); other configurations may work as well depending upon the board setup (for example, using the on-chip pull-ups).


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GPIO

Note:

This cannot be used to turn any pin into a timer pin; it only configures a timer pin for proper operation.

Returns:

None.

7.2.2.22 GPIOPinTypeUART

Configures pin(s) for use by the UART peripheral.

Prototype:

void

GPIOPinTypeUART(unsigned long ulPort, unsigned char ucPins)

Parameters:



Description:

The UART pins must be properly configured for the UART peripheral to function correctly. This function provides a typical configuration for those pin(s); other configurations may work as well depending upon the board setup (for example, using the on-chip pull-ups).


Note:

This cannot be used to turn any pin into a UART pin; it only configures a UART pin for proper operation.

Returns:

None.

7.2.2.23 GPIOPinWrite

Writes a value to the specified pin(s).

Prototype:

void

GPIOPinWrite(unsigned long ulPort, unsigned char ucPins, unsigned char ucVal)

Parameters:



ucVal is the value to write to the pin(s).

90 October 11, 2007


Description:

Writes the corresponding bit values to the output pin(s) specified by ucPins. Writing to a pin configured as an input pin has no effect.


Returns:

None.

7.2.2.24 GPIOPortIntRegister

Registers an interrupt handler for a GPIO port.

Prototype:

void

GPIOPortIntRegister(unsigned long ulPort, void (*pfIntHandler)(void))

Parameters:


pfIntHandler is a pointer to the GPIO port interrupt handling function.

Description:

This function will ensure that the interrupt handler specified by pfIntHandler is called when an interrupt is detected from the selected GPIO port. This function will also enable the corresponding GPIO interrupt in the interrupt controller; individual pin interrupts and interrupt sources must be enabled with

GPIOPinIntEnable() .

See also:

IntRegister()


Returns:

None.

7.2.2.25 GPIOPortIntUnregister

Removes an interrupt handler for a GPIO port.

Prototype:

void

GPIOPortIntUnregister(unsigned long ulPort)

Parameters:


Description:

This function will unregister the interrupt handler for the specified GPIO port. This function will also disable the corresponding GPIO port interrupt in the interrupt controller; individual GPIO interrupts and interrupt sources must be disabled with

GPIOPinIntDisable() .

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See also:

IntRegister()


Returns:

None.

7.3


The following example shows how to use the GPIO API to initialize the GPIO, enable interrupts, read data from pins, and write data to pins.

int iVal;

//

// Register the port-level interrupt handler. This handler is the

// first level interrupt handler for all the pin interrupts.

//

GPIOPortIntRegister(GPIO_PORTA_BASE, PortAIntHandler);

//

// Initialize the GPIO pin configuration.

//

// Set pins 2, 4, and 5 as input, SW controlled.

//

GPIODirModeSet(GPIO_PORTA_BASE, (GPIO_PIN_2 | GPIO_PIN_4 | GPIO_PIN_5),

GPIO_DIR_MODE_IN);

//

// Set pins 0 and 3 as output, SW controlled.

//

GPIODirModeSet(GPIO_PORTA_BASE, (GPIO_PIN_0 | GPIO_PIN_3),

GPIO_DIR_MODE_OUT);

//

// Make pins 2 and 4 rising edge triggered interrupts.

//

GPIOIntTypeSet(GPIO_PORTA_BASE, (GPIO_PIN_2 | GPIO_PIN_4),

GPIO_RISING_EDGE);

//

// Make pin 5 high level triggered interrupts.

//

GPIOIntTypeSet(GPIO_PORTA_BASE, GPIO_PIN_5, GPIO_HIGH_LEVEL);

//

// Read some pins.

// iVal = GPIOPinRead(GPIO_PORTA_BASE,

(GPIO_PIN_0 | GPIO_PIN_2 | GPIO_PIN_3 |

GPIO_PIN_4 | GPIO_PIN_5));

//

// Write some pins.

Even though pins 2, 4, and 5 are specified, those

// pins are unaffected by this write since they are configured as inputs.

// At the end of this write, pin 0 will be a 0, and pin 3 will be a 1.

//

GPIOPinWrite(GPIO_PORTA_BASE,

(GPIO_PIN_0 | GPIO_PIN_2 | GPIO_PIN_3 |

GPIO_PIN_4 | GPIO_PIN_5),

0xF4);

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//

// Enable the pin interrupts.

//

GPIOPinIntEnable(GPIO_PORTA_BASE, (GPIO_PIN_2 | GPIO_PIN_4 | GPIO_PIN_5));

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94 October 11, 2007

8


Hibernation Module

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Programming Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105

8.1

Introduction

The Hibernate API provides a set of functions for using the Stellaris microcontroller’s Hibernation module. The Hibernation module allows the software application to cause power to be removed from the microcontroller, and then be powered on later based on specific time or a signal on the external WAKE pin. The API provides functions to configure wake conditions, manage interrupts, read status, save and restore program state information, and request hibernation mode.

Some of the features of the Hibernation module are:

32-bit real time clock

Trim register for fine tuning the RTC rate

Two RTC match registers for generating RTC events

External WAKE pin to initiate a wake-up

Low-battery detection

64 32-bit words of non-volatile memory

Programmable interrupts for hibernation events

8.2

API Functions

Functions void

HibernateClockSelect

(unsigned long ulClockInput) void

HibernateDataGet

(unsigned long ∗pulData, unsigned long ulCount) void

HibernateDataSet

(unsigned long ∗pulData, unsigned long ulCount) void

HibernateDisable

(void) void

HibernateEnableExpClk

(unsigned long ulHibClk) void

HibernateIntClear


HibernateIntDisable


HibernateIntEnable


HibernateIntRegister

(void (∗pfnHandler)(void)) unsigned long

HibernateIntStatus


HibernateIntUnregister

(void) unsigned int

HibernateIsActive

(void) unsigned long

HibernateLowBatGet

(void) void

HibernateLowBatSet

(unsigned long ulLowBatFlags) void

HibernateRequest

(void)

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Hibernation Module void

HibernateRTCDisable

(void) void

HibernateRTCEnable


HibernateRTCGet


HibernateRTCMatch0Get

(void) void

HibernateRTCMatch0Set

(unsigned long ulMatch) unsigned long

HibernateRTCMatch1Get

(void) void

HibernateRTCMatch1Set

(unsigned long ulMatch) void

HibernateRTCSet

(unsigned long ulRTCValue) unsigned long

HibernateRTCTrimGet

(void) void

HibernateRTCTrimSet

(unsigned long ulTrim) unsigned long

HibernateWakeGet

(void) void

HibernateWakeSet

(unsigned long ulWakeFlags)

8.2.1


The Hibernation module must be enabled before it can be used. Use the

HibernateEnableExp-

Clk()

function to enable it. If a crystal is used for the clock source, then the initializing code must allow time for the crystal to stabilize after calling the

HibernateEnableExpClk()

function. Refer to the device data sheet for information about crystal stabilization time. If an oscillator is used, then no delay is necessary. After the module is enabled, the clock source must be configured by calling

HibernateClockSelect() .

In order to use the RTC feature of the Hibernation module, the RTC must be enabled by calling

HibernateRTCEnable() . It can be later disabled by calling

HibernateRTCDisable() . These functions

can be called at any time to start and stop the RTC. The RTC value can be read or set by using the functions

HibernateRTCGet()

and

HibernateRTCSet() . The two match registers can be read

and set by using the functions

HibernateRTCMatch0Get() , HibernateRTCMatch0Set() ,

Hibernate-

RTCMatch1Get()

and

HibernateRTCMatch1Set() . The real time clock rate can be adjusted by using

the trim register. Use the functions

HibernateRTCTrimGet()

and

HibernateRTCTrimSet()

function for this purpose.

Application state information can be stored in the non-volatile memory of the Hibernation module when the processor is powered off. Use the functions

HibernateDataSet()

and

HibernateDataGet()

to access the non-volatile memory area.

The module can be configured to wake when the external WAKE pin is asserted, or when an RTC match occurs, or both. Use the function

HibernateWakeSet()

to configure the wake conditions. The present configuration can be read by calling

HibernateWakeGet() .

The Hibernation module can detect a low battery and signal the processor. It can also be configured to abort a hibernation request if the battery voltage is too low. Use the functions

HibernateLowBat-

Set()

and

HibernateLowBatGet()

to configure this feature.

Several functions are provided for managing interrupts. Use the function

HibernateIntRegister()

and

HibernateIntUnregister()

to install or uninstall an interrupt handler into the vector table. Refer to the

IntRegister()

function for notes about using the interrupt vector table. The module can generate several different interrupts. Use the functions

HibernateIntEnable()

and

HibernateIntDisable()

to enable and disable specific interrupt sources. The present interrupt status can be found by calling

HibernateIntStatus() . In the interrupt handler, all pending interrupts must be cleared. Use the

HibernateIntClear()

function to clear pending interrupts.

Finally, once the module is appropriately configured, the state saved and the software application is ready to hibernate, call the

HibernateRequest()

function. This will initiate the sequence to remove

96 October 11, 2007

Stellaris Peripheral Driver Library User’s Guide power from the processor. At a power-on reset, the software application can use the

Hibernate-

IsActive()

function to determine if the Hibernation module is already active and therefore does not need to be enabled. This can provide a hint to the software that the processor is waking from hibernation instead of a cold start. The software can then use the

HibernateIntStatus()

and

HibernateDataGet()

functions to discover the cause of the wake and to get the saved system state.

The HibernateEnable() API from previous versions of the Peripheral Driver Library has been replaced by the

HibernateEnableExpClk()

API. A macro has been provided in hibernate.h to map the old API to the new API, allowing existing applications to link and run with the new API. It is recommended that new applications utilize the new API in favor of the old one.

8.2.2


8.2.2.1

HibernateClockSelect

Selects the clock input for the hibernation module.

Prototype:

void

HibernateClockSelect(unsigned long ulClockInput)

Parameters:

ulClockInput specifies the clock input.

Description:

Configures the clock input for the hibernation module. The configuration option chosen depends entirely on hardware design. The clock input for the module will either be a 32.768 kHz oscillator or a 4.194304 MHz crystal. The parameter ulClockFlags must be one of the following:

HIBERNATE_CLOCK_SEL_RAW - use the raw signal from a 32.768 kHz oscillator.

HIBERNATE_CLOCK_SEL_DIV128 - use the crystal input, divided by 128.

Returns:

None.

8.2.2.2

HibernateDataGet

Reads a set of data from the non-volatile memory of the hibernation module.

Prototype:

void

HibernateDataGet(unsigned long *pulData, unsigned long ulCount)

Parameters:

pulData points to a location where the data that is read from the hibernation module will be stored.

ulCount is the count of 32 bit words to read.

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Hibernation Module

Description:

Retrieves a set of data from the hibernation module non-volatile memory that was previously stored with the

HibernateDataSet()

function. The caller must ensure that pulData points to a large enough memory block to hold all the data that is read from the non-volatile memory.

Returns:

None.

8.2.2.3

HibernateDataSet

Stores data in the non-volatile memory of the hibernation module.

Prototype:

void

HibernateDataSet(unsigned long *pulData, unsigned long ulCount)

Parameters:

pulData points to the data that the caller wants to store in the memory of the hibernation module.

ulCount is the count of 32 bit words to store.

Description:

Stores a set of data in the hibernation module non-volatile memory. This memory will be preserved when the power to the processor is turned off, and can be used to store application state information which will be available when the processor wakes. Up to 64 32-bit words can be stored in the non-volatile memory. The data can be restored by calling the

HibernateData-

Get()

function.

Returns:

None.

8.2.2.4

HibernateDisable

Disables the hibernation module for operation.

Prototype:

void

HibernateDisable(void)

Description:

Disables the hibernation module for operation. After this function is called, none of the hibernation module features are available.

Returns:

None.

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8.2.2.5

HibernateEnableExpClk

Enables the hibernation module for operation.

Prototype:

void

HibernateEnableExpClk(unsigned long ulHibClk)

Parameters:

ulHibClk is the rate of the clock supplied to the hibernateion module.

Description:

Enables the hibernation module for operation. This function should be called before any of the hibernation module features are used.




SysCtlClockGet() ).

This function replaces the original HibernateEnable() API and performs the same actions. A macro is provided in hibernate.h to map the original API to this API.

Returns:

None.

8.2.2.6

HibernateIntClear

Clears pending interrupts from the Hibernation module.

Prototype:

void

HibernateIntClear(unsigned long ulIntFlags)

Parameters:

ulIntFlags is the bit mask of the interrupts to be cleared.

Description:

Clears the specified interrupt sources. This must be done from within the interrupt handler or else the handler will be called again upon exit.

The parameter ulIntFlags has the same definition as in the


function.

Returns:

None.

8.2.2.7

HibernateIntDisable

Disables interrupts for the Hibernation module.

Prototype:

void

HibernateIntDisable(unsigned long ulIntFlags)

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Hibernation Module

Parameters:

ulIntFlags is the bit mask of the interrupts to be disabled.

Description:

Disables the specified interrupt sources from the hibernation module.

The parameter ulIntFlags has the same definition as in the


function.

Returns:

None.

8.2.2.8

HibernateIntEnable

Enables interrupts for the Hibernation module.

Prototype:

void

HibernateIntEnable(unsigned long ulIntFlags)

Parameters:

ulIntFlags is the bit mask of the interrupts to be enabled.

Description:

Enables the specified interrupt sources from the hibernation module.

The parameter ulIntFlags must be the logical OR of any combination of the following:

HIBERNATE_INT_PIN_WAKE - wake from pin interrupt

HIBERNATE_INT_LOW_BAT - low battery interrupt

HIBERNATE_INT_RTC_MATCH_0 - RTC match 0 interrupt

HIBERNATE_INT_RTC_MATCH_1 - RTC match 1 interrupt

Returns:

None.

8.2.2.9

HibernateIntRegister

Registers an interrupt handler for the hibernation module interrupt.

Prototype:

void

HibernateIntRegister(void (*pfnHandler)(void))

Parameters:

pfnHandler points to the function to be called when a hibernation interrupt occurs.

Description:

Registers the interrupt handler in the system interrupt controller. The interrupt is enabled at the global level, but individual interrupt sources must still be enabled with a call to

Hibernate-

IntEnable() .

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See also:

IntRegister()


Returns:

None.

8.2.2.10 HibernateIntStatus

Gets the current interrupt status of the Hibernation module.

Prototype:

unsigned long

HibernateIntStatus(tBoolean bMasked)

Parameters:

bMasked is false to retrieve the raw interrupt status, and true to retrieve the masked interrupt status.

Description:

Returns the interrupt status of the hibernation module. The caller can use this to determine the cause of a hibernation interrupt. Either the masked or raw interrupt status can be returned.

Returns:

The interrupt status as a bit field with the values as described in the


function.

8.2.2.11 HibernateIntUnregister

Unregisters an interrupt handler for the hibernation module interrupt.

Prototype:

void

HibernateIntUnregister(void)

Description:

Unregisters the interrupt handler in the system interrupt controller. The interrupt is disabled at the global level, and the interrupt handler will no longer be called.

See also:

IntRegister()


Returns:

None.

8.2.2.12 HibernateIsActive

Checks to see if the Hibernation module is already powered up.

October 11, 2007 101

Hibernation Module

Prototype:

unsigned int

HibernateIsActive(void)

Description:

This function queries the control register to determine if the module is already active. This function can be called at a power-on reset to help determine if the reset is due to a wake from hibernation or a cold start. If the Hibernation module is already active, then it does not need to be re-enabled and it’s status can be queried immediately.

The software application should also use the

HibernateIntStatus()

function to read the raw interrupt status to determine the cause of the wake. The

HibernateDataGet()

function can be used to restore state. These combinations of functions can be used by the software to determine if the processor is waking from hibernation and the appropriate action to take as a result.

Returns:

True if the module is already active, false if not.

8.2.2.13 HibernateLowBatGet

Gets the currently configured low battery detection behavior.

Prototype:

unsigned long

HibernateLowBatGet(void)

Description:

Returns a value representing the currently configured low battery detection behavior. The return value will be one of the following:

HIBERNATE_LOW_BAT_DETECT - detect a low battery condition.

HIBERNATE_LOW_BAT_ABORT - detect a low battery condition, and abort hibernation if low battery is detected.

Returns:

a value indicating the configured low battery detection.

8.2.2.14 HibernateLowBatSet

Configures the low battery detection.

Prototype:

void

HibernateLowBatSet(unsigned long ulLowBatFlags)

Parameters:

ulLowBatFlags specifies behavior of low battery detection.

Description:

Enables the low battery detection and whether hibernation is allowed if a low battery is detected. If low battery detection is enabled, then a low battery condition will be indicated in the

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Stellaris Peripheral Driver Library User’s Guide raw interrupt status register, and can also trigger an interrupt. Optionally, hibernation can be aborted if a low battery is detected.

The parameter ulLowBatFlags is one of the following values:

HIBERNATE_LOW_BAT_DETECT - detect a low battery condition.

HIBERNATE_LOW_BAT_ABORT - detect a low battery condition, and abort hibernation if low battery is detected.

Returns:

None.

8.2.2.15 HibernateRequest

Requests Hibernation mode.

Prototype:

void

HibernateRequest(void)

Description:

This function requests the Hibernation module to disable the external regulator, thus removing power from the processor and all peripherals. The hibernation module will remain powered from the battery or auxiliary power supply.

The hibernation module will re-enable the external regulator when one of the configured wake conditions occurs (such as RTC match or external WAKE pin). When the power is restored the processor will go through a normal power-on reset. The processor can retrieve saved state information with the

HibernateDataGet()

function. Prior to calling the function to request hibernation mode, the conditions for waking must have already been set by using the

Hibernate-

WakeSet()

function.

Note that this function may return because some time may elapse before the power is actually removed, or it may not be removed at all. For this reason the processor will continue to execute instructions for some time and the caller should be prepared for this function to return. There are various reasons why the power may not be removed. For example if the HibernationLow-

BatSet() function was used to configure an abort if low battery is detected, then the power will not be removed if the battery voltage is too low. There may be other reasons, related to the external circuit design, why a request for hibernation may not actually occur.

For all these reasons, the caller must be prepared for this function to return. The simplest way to handle it is to just enter an infinite loop and wait for the power to be removed.

Returns:

None.

8.2.2.16 HibernateRTCDisable

Disables the RTC feature of the hibernation module.

Prototype:

void

HibernateRTCDisable(void)

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Hibernation Module

Description:

Disables the RTC in the hibernation module. After calling this function the RTC features of the hibernation module will not be available.

Returns:

None.

8.2.2.17 HibernateRTCEnable

Enables the RTC feature of the hibernation module.

Prototype:

void

HibernateRTCEnable(void)

Description:

Enables the RTC in the hibernation module. The RTC can be used to wake the processor from hibernation at a certain time, or to generate interrupts at certain times. This function must be called before using any of the RTC features of the hibernation module.

Returns:

None.

8.2.2.18 HibernateRTCGet

Gets the value of the real time clock (RTC) counter.

Prototype:

unsigned long

HibernateRTCGet(void)

Description:

Gets the value of the RTC and returns it to the caller.

Returns:

the value of the RTC.

8.2.2.19 HibernateRTCMatch0Get

Gets the value of the RTC match 0 register.

Prototype:

unsigned long

HibernateRTCMatch0Get(void)

Description:

Gets the value of the match 0 register for the RTC.

Returns:

the value of the match register.

104 October 11, 2007


8.2.2.20 HibernateRTCMatch0Set

Sets the value of the RTC match 0 register.

Prototype:

void

HibernateRTCMatch0Set(unsigned long ulMatch)

Parameters:

ulMatch is the value for the match register.

Description:

Sets the match 0 register for the RTC. The hibernation module can be configured to wake from hibernation, and/or generate an interrupt when the value of the RTC counter is the same as the match register.

Returns:

None.

8.2.2.21 HibernateRTCMatch1Get

Gets the value of the RTC match 1 register.

Prototype:

unsigned long

HibernateRTCMatch1Get(void)

Description:

Gets the value of the match 1 register for the RTC.

Returns:

the value of the match register.

8.2.2.22 HibernateRTCMatch1Set

Sets the value of the RTC match 1 register.

Prototype:

void

HibernateRTCMatch1Set(unsigned long ulMatch)

Parameters:

ulMatch is the value for the match register.

Description:

Sets the match 1 register for the RTC. The hibernation module can be configured to wake from hibernation, and/or generate an interrupt when the value of the RTC counter is the same as the match register.

Returns:

None.

October 11, 2007 105

Hibernation Module

8.2.2.23 HibernateRTCSet

Sets the value of the real time clock (RTC) counter.

Prototype:

void

HibernateRTCSet(unsigned long ulRTCValue)

Parameters:

ulRTCValue is the new value for the RTC.

Description:

Sets the value of the RTC. The RTC will count seconds if the hardware is configured correctly.

The RTC must be enabled by calling

HibernateRTCEnable()

before calling this function.

Returns:

None.

8.2.2.24 HibernateRTCTrimGet

Gets the value of the RTC predivider trim register.

Prototype:

unsigned long

HibernateRTCTrimGet(void)

Description:

Gets the value of the pre-divider trim register. This function can be used to get the current value of the trim register prior to making an adjustment by using the

HibernateRTCTrimSet()

function.

Returns:

None.

8.2.2.25 HibernateRTCTrimSet

Sets the value of the RTC predivider trim register.

Prototype:

void

HibernateRTCTrimSet(unsigned long ulTrim)

Parameters:

ulTrim is the new value for the pre-divider trim register.

Description:

Sets the value of the pre-divider trim register. The input time source is divided by the predivider to achieve a one second clock rate. Once every 64 seconds, the value of the pre-divider trim register is applied to the predivider to allow fine tuning of the RTC rate, in order to make corrections to the rate. The software application can make adjustments to the predivider trim register to account for variations in the accuracy of the input time source. The nominal value is

0x7FFF, and it can be adjusted up or down in order to fine tune the RTC rate.

106 October 11, 2007


Returns:

None.

8.2.2.26 HibernateWakeGet

Gets the currently configured wake conditions for the hibernation module.

Prototype:

unsigned long

HibernateWakeGet(void)

Description:

Returns the flags representing the wake configuration for the hibernation module. The return value will be a combination of the following flags:

HIBERNATE_WAKE_PIN - wake when the external wake pin is asserted.

HIBERNATE_WAKE_RTC - wake when one of the RTC matches occurs.

Returns:

flags indicating the configured wake conditions.

8.2.2.27 HibernateWakeSet

Configures the wake conditions for the hibernation module.

Prototype:

void

HibernateWakeSet(unsigned long ulWakeFlags)

Parameters:

ulWakeFlags specifies which conditions should be used for waking.

Description:

Enables the conditions under which the hibernation module will wake. The parameter ulWake-

Flags is the logical or of any combination of the following:

HIBERNATE_WAKE_PIN - wake when the external wake pin is asserted.

HIBERNATE_WAKE_RTC - wake when one of the RTC matches occurs.

Returns:

None.

8.3


The following example shows how to determine if the processor reset is due to a wake from hibernation, and to restore saved state:

October 11, 2007 107

Hibernation Module unsigned long ulStatus; unsigned long ulNVData[64];

//

// Need to enable the hibernation peripheral after wake/reset,

// before using it.

//

SysCtlPeripheralEnable(SYSCTL_PERIPH_HIBERNATE);

//

// Determine if the hibernate module is active.

// if(HibernateIsActive())

{

//

// Read the status to determine cause of wake.

// ulStatus = HibernateIntStatus(0); // read unmasked status

//

// Test the status bits to see the cause.

// if(ulStatus & HIBERNATE_INT_PIN_WAKE)

{

// Wakeup was due to WAKE pin assertion

} if(ulStatus & HIBERNATE_INT_RTC_MATCH_0)

{

// Wakeup was due to RTC match0 register

}

//

// Restore program state information that was saved prior

// to hibernation.

//

HibernateDataGet(ulNVData, 64);

//

// Now that wakeup cause has been determined and state has been

// restored, the program can proceed with normal processor and

// peripheral initialization.

//

}

//

// Hibernate module was not active so this is a cold power-up/reset.

// else

{

//

// Perform normal power-on initialization.

//

}

The following example shows how to set up the hibernation module and initiate a hibernation with wake up at a future time: unsigned long ulStatus; unsigned long ulNVData[64];

//

// Need to enable the hibernation peripheral before using it.

//


108 October 11, 2007


//

// Enable clocking to the Hibernation module.

//

HibernateEnableExpClk(SysCtlClockGet());

//

// User-implemented delay here to allow crystal to power up and

// stabilize.

//

//

// Configure the clock source for hibernate module,

// and enable the RTC feature.

This configuration is

// for a 4.194304 MHz crystal.

//

HibernateClockSelect(HIBERNATE_CLOCK_SEL_DIV128);

HibernateRTCEnable();

//

// Set the RTC to 0, or an initial value.

The RTC can be set once

// when the system is initialized after the cold-startup, and then

// left to run.

Or it can be initialized before every hibernate.

//

HibernateRTCSet(0);

//

// Set the match 0 register for 30 seconds from now.

//

HibernateRTCMatch0Set(HibernateRTCGet() + 30);

//

// Clear any pending status

// ulStatus = HibernateIntStatus(0);

HibernateIntClear(ulStatus);

//

// Save the program state information.

The state information should

// be stored in the ulNVData[] array.

It is not necessary to save

// the full 64 words of data, only as much as is actually needed

// by the program.

//

HibernateDataSet(ulNVData, 64);

//

// Configure to wake on RTC match.

//

HibernateWakeSet(HIBERNATE_WAKE_RTC);

//

// Request hibernation.

The following call may return since it

// takes a finite amount of time for power to be removed.

//

HibernateRequest();

//

// Need a loop here to wait for the power to be removed.

Power will

// be removed while executing in this loop.

// for(;;)

{

}

The following example shows how to use the hibernation module RTC to generate an interrupt at a certain time:

October 11, 2007 109

Hibernation Module

//

// Handler for hibernate interrupts.

/ void

HibernateHandler(void)

{ unsigned long ulStatus;

//

// Get the interrupt status, and clear any pending interrupts.

// ulStatus = HibernateIntStatus(1);

HibernateIntClear(ulStatus);

//

// Process the RTC match 0 interrupt

// if(ulStatus & HIBERNATE_INT_RTC_MATCH_0)

{

//

// RTC match 0 interrupt actions go here.

//

}

}

//

// Main function.

// int main(void)

{

//

// System initialization code ...

//

//

// Enable the hibernation module

//


HibernateEnableExpClk(SysCtlClockGet());

//

// Wait an amount of time for the module to power up.

//

//

// Configure the clock source for hibernate module,

// and enable the RTC feature.

This configuration

// is for the 4.194304 MHz crystal.

//

HibernateClockSelect(HIBERNATE_CLOCK_SEL_DIV128);

HibernateRTCEnable();

//

// Set the RTC to an initial value.

//

HibernateRTCSet(0);

//

// Set Match 0 for 30 seconds from now.

//

HibernateRTCMatch0Set(HibernateRTCGet() + 30);

//

// Set up interrupts on the hibernation module to enable the

// RTC match 0 interrupt.

Clear all pending interrupt and

110 October 11, 2007


// register the interrupt handler.

//

HibernateIntEnable(HIBERNATE_INT_RTC_MATCH_0);

HibernateIntClear(HIBERNATE_INT_PIN_WAKE | HIBERNATE_INT_LOW_BAT |

HIBERNATE_INT_RTC_MATCH_0 | HIBERNATE_INT_RTC_MATCH_1);

HibernateIntRegister(HibernateHandler);

//

// Hibernate handler (above) will now be invoked in 30 seconds.

//

// ...

October 11, 2007 111

Hibernation Module

112 October 11, 2007

9


I2C

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112


9.1

Introduction

The Inter-Integrated Circuit (I2C) API provides a set of functions for using the Stellaris I2C master and slave modules. Functions are provided to initialize the I2C modules, to send and receive data, obtain status, and to manage interrupts for the I2C modules.

The I2C master and slave modules provide the ability to communicate to other IC devices over an

I2C bus. The I2C bus is specified to support devices that can both transmit and receive (write and read) data. Also, devices on the I2C bus can be designated as either a master or a slave. The

Stellaris I2C modules support both sending and receiving data as either a master or a slave, and also support the simultaneous operation as both a master and a slave. Finally, the Stellaris I2C modules can operate at two speeds: Standard (100 kb/s) and Fast (400 kb/s).

Both the master and slave I2C modules can generate interrupts. The I2C master module will generate interrupts when a transmit or receive operation is completed (or aborted due to an error).

The I2C slave module will generate interrupts when data has been sent or requested by a master.

9.1.1

Master Operations

When using this API to drive the I2C master module, the user must first initialize the I2C master module with a call to

I2CMasterInitExpClk() . That function will set the bus speed and enable the

master module.

The user may transmit or receive data after the successful initialization of the I2C master module.

Data is transferred by first setting the slave address using

I2CMasterSlaveAddrSet() . That function

is also used to define whether the transfer is a send (a write to the slave from the master) or a receive (a read from the slave by the master). Then, if connected to an I2C bus that has multiple masters, the Stellaris I2C master must first call

I2CMasterBusBusy()

before attempting to initiate the desired transaction. After determining that the bus is not busy, if trying to send data, the user must call the

I2CMasterDataPut()

function. The transaction can then be initiated on the bus by calling the

I2CMasterControl()

function with any of the following commands:

I2C_MASTER_CMD_SINGLE_SEND

I2C_MASTER_CMD_SINGLE_RECEIVE

I2C_MASTER_CMD_BURST_SEND_START

I2C_MASTER_CMD_BURST_RECEIVE_START

Any of those commands will result in the master arbitrating for the bus, driving the start sequence onto the bus, and sending the slave address and direction bit across the bus. The remainder of the transaction can then be driven using either a polling or interrupt-driven method.

For the single send and receive cases, the polling method will involve looping on the return from

I2CMasterBusy() . Once that function indicates that the I2C master is no longer busy, the bus

October 11, 2007 113

I2C transaction has been completed and can be checked for errors using

I2CMasterErr() . If there are no

errors, then the data has been sent or is ready to be read using

I2CMasterDataGet() . For the burst

send and receive cases, the polling method also involves calling the

I2CMasterControl()

function for each byte transmitted or received (using either the I2C_MASTER_CMD_BURST_SEND_CONT or

I2C_MASTER_CMD_BURST_RECEIVE_CONT commands), and for the last byte sent or received

(using either the I2C_MASTER_CMD_BURST_SEND_FINISH or I2C_MASTER_CMD_BURST_-

RECEIVE_FINISH commands). If any error is detected during the burst transfer, the

I2CMaster-

Control()

function should be called using the appropriate stop command (I2C_MASTER_CMD_-

BURST_SEND_ERROR_STOP or I2C_MASTER_CMD_BURST_RECEIVE_ERROR_STOP).

For the interrupt-driven transaction, the user must register an interrupt handler for the I2C devices and enable the I2C master interrupt; the interrupt will occur when the master is no longer busy.

9.1.2

Slave Operations

When using this API to drive the I2C slave module, the user must first initialize the I2C slave module with a call to

I2CSlaveInit() . This will enable the I2C slave module and initialize the slave’s

own address. After the initialization is complete, the user may poll the slave status using

I2CSlave-

Status()

to determine if a master requested a send or receive operation. Depending on the type of operation requested, the user can call

I2CSlaveDataPut()

or

I2CSlaveDataGet()

to complete the transaction. Alternatively, the I2C slave can handle transactions using an interrupt handler registered with I2CIntRegister, and by enabling the I2C slave interrupt.

9.2

API Functions

Functions void

I2CIntRegister

(unsigned long ulBase, void (∗pfnHandler)(void)) void

I2CIntUnregister


I2CMasterBusBusy


I2CMasterBusy


I2CMasterControl

(unsigned long ulBase, unsigned long ulCmd) unsigned long

I2CMasterDataGet


I2CMasterDataPut

(unsigned long ulBase, unsigned char ucData) void

I2CMasterDisable


I2CMasterEnable

(unsigned long ulBase) unsigned long

I2CMasterErr


I2CMasterInitExpClk

(unsigned long ulBase, unsigned long ulI2CClk, tBoolean bFast) void

I2CMasterIntClear


I2CMasterIntDisable


I2CMasterIntEnable


I2CMasterIntStatus


I2CMasterSlaveAddrSet

(unsigned long ulBase, unsigned char ucSlaveAddr, tBoolean bReceive) unsigned long

I2CSlaveDataGet


I2CSlaveDataPut

(unsigned long ulBase, unsigned char ucData)

114 October 11, 2007

Stellaris Peripheral Driver Library User’s Guide void

I2CSlaveDisable


I2CSlaveEnable


I2CSlaveInit

(unsigned long ulBase, unsigned char ucSlaveAddr) void

I2CSlaveIntClear


I2CSlaveIntDisable


I2CSlaveIntEnable


I2CSlaveIntStatus

(unsigned long ulBase, tBoolean bMasked) unsigned long

I2CSlaveStatus


9.2.1


The I2C API is broken into three groups of functions: those that deal with interrupts, those that handle status and initialization, and those that deal with sending and receiving data.

The I2C master and slave interrupts are handled by the

I2CIntRegister() ,

I2CInt-

Unregister() ,

I2CMasterIntEnable() ,

I2CMasterIntDisable() , I2CMasterIntClear() ,

I2CMasterInt-

Status() ,

I2CSlaveIntEnable() , I2CSlaveIntDisable() , I2CSlaveIntClear() , and

I2CSlaveIntStatus()

functions.

Status and initialization functions for the I2C modules are

I2CMasterInitExpClk() ,

I2CMaster-

Enable() , I2CMasterDisable() ,

I2CMasterBusBusy() , I2CMasterBusy() ,

I2CMasterErr() ,

I2CSlave-

Init() , I2CSlaveEnable() ,

I2CSlaveDisable() , and

I2CSlaveStatus() .

Sending and receiving data from the I2C modules are handled by the

I2CMasterSlaveAddrSet() ,

I2CMasterControl() , I2CMasterDataGet() ,

I2CMasterDataPut() ,

I2CSlaveDataGet() , and I2CSlave-

DataPut()

functions.

The I2CMasterInit() API from previous versions of the Peripheral Driver Library has been replaced by the

I2CMasterInitExpClk()

API. A macro has been provided in i2c.h to map the old API to the new API, allowing existing applications to link and run with the new API. It is recommended that new applications utilize the new API in favor of the old one.

9.2.2


9.2.2.1

I2CIntRegister

Registers an interrupt handler for the I2C module.

Prototype:

void

I2CIntRegister(unsigned long ulBase, void (*pfnHandler)(void))

Parameters:

ulBase is the base address of the I2C Master module.

pfnHandler is a pointer to the function to be called when the I2C interrupt occurs.

Description:

This sets the handler to be called when an I2C interrupt occurs. This will enable the global interrupt in the interrupt controller; specific I2C interrupts must be enabled via

I2CMasterInt-

October 11, 2007 115

I2C

Enable() and

I2CSlaveIntEnable() . If necessary, it is the interrupt handler’s responsibility to

clear the interrupt source via

I2CMasterIntClear()

and

I2CSlaveIntClear() .

See also:

IntRegister()


Returns:

None.

9.2.2.2

I2CIntUnregister

Unregisters an interrupt handler for the I2C module.

Prototype:

void

I2CIntUnregister(unsigned long ulBase)

Parameters:


Description:

This function will clear the handler to be called when an I2C interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

See also:

IntRegister()


Returns:

None.

9.2.2.3

I2CMasterBusBusy

Indicates whether or not the I2C bus is busy.

Prototype:

tBoolean

I2CMasterBusBusy(unsigned long ulBase)

Parameters:


Description:

This function returns an indication of whether or not the I2C bus is busy. This function can be used in a multi-master environment to determine if another master is currently using the bus.

Returns:

Returns true if the I2C bus is busy; otherwise, returns false.

116 October 11, 2007


9.2.2.4

I2CMasterBusy

Indicates whether or not the I2C Master is busy.

Prototype:

tBoolean

I2CMasterBusy(unsigned long ulBase)

Parameters:


Description:

This function returns an indication of whether or not the I2C Master is busy transmitting or receiving data.

Returns:

Returns true if the I2C Master is busy; otherwise, returns false.

9.2.2.5

I2CMasterControl

Controls the state of the I2C Master module.

Prototype:

void

I2CMasterControl(unsigned long ulBase, unsigned long ulCmd)

Parameters:


ulCmd command to be issued to the I2C Master module

Description:

This function is used to control the state of the Master module send and receive operations.

The parameter ucCmd can be one of the following values:

I2C_MASTER_CMD_SINGLE_SEND

I2C_MASTER_CMD_SINGLE_RECEIVE

I2C_MASTER_CMD_BURST_SEND_START

I2C_MASTER_CMD_BURST_SEND_CONT

I2C_MASTER_CMD_BURST_SEND_FINISH

I2C_MASTER_CMD_BURST_SEND_ERROR_STOP

I2C_MASTER_CMD_BURST_RECEIVE_START

I2C_MASTER_CMD_BURST_RECEIVE_CONT

I2C_MASTER_CMD_BURST_RECEIVE_FINISH

I2C_MASTER_CMD_BURST_RECEIVE_ERROR_STOP

Returns:

None.

October 11, 2007 117

I2C

9.2.2.6

I2CMasterDataGet

Receives a byte that has been sent to the I2C Master.

Prototype:

unsigned long

I2CMasterDataGet(unsigned long ulBase)

Parameters:


Description:

This function reads a byte of data from the I2C Master Data Register.

Returns:

Returns the byte received from by the I2C Master, cast as an unsigned long.

9.2.2.7

I2CMasterDataPut

Transmits a byte from the I2C Master.

Prototype:

void

I2CMasterDataPut(unsigned long ulBase, unsigned char ucData)

Parameters:


ucData data to be transmitted from the I2C Master

Description:

This function will place the supplied data into I2C Master Data Register.

Returns:

None.

9.2.2.8

I2CMasterDisable

Disables the I2C master block.

Prototype:

void

I2CMasterDisable(unsigned long ulBase)

Parameters:


Description:

This will disable operation of the I2C master block.

Returns:

None.

118 October 11, 2007


9.2.2.9

I2CMasterEnable

Enables the I2C Master block.

Prototype:

void

I2CMasterEnable(unsigned long ulBase)

Parameters:


Description:

This will enable operation of the I2C Master block.

Returns:

None.

9.2.2.10 I2CMasterErr

Gets the error status of the I2C Master module.

Prototype:

unsigned long

I2CMasterErr(unsigned long ulBase)

Parameters:


Description:

This function is used to obtain the error status of the Master module send and receive operations. It returns one of the following values:

I2C_MASTER_ERR_NONE

I2C_MASTER_ERR_ADDR_ACK

I2C_MASTER_ERR_DATA_ACK

I2C_MASTER_ERR_ARB_LOST

Returns:

None.

9.2.2.11 I2CMasterInitExpClk

Initializes the I2C Master block.

Prototype:

void

I2CMasterInitExpClk(unsigned long ulBase, unsigned long ulI2CClk, tBoolean bFast)

Parameters:


October 11, 2007 119

I2C

ulI2CClk is the rate of the clock supplied to the I2C module.

bFast set up for fast data transfers

Description:

This function initializes operation of the I2C Master block. Upon successful initialization of the

I2C block, this function will have set the bus speed for the master, and will have enabled the

I2C Master block.

If the parameter bFast is true, then the master block will be set up to transfer data at 400 kbps; otherwise, it will be set up to transfer data at 100 kbps.




SysCtlClockGet() ).

This function replaces the original I2CMasterInit() API and performs the same actions. A macro is provided in i2c.h to map the original API to this API.

Returns:

None.

9.2.2.12 I2CMasterIntClear

Clears I2C Master interrupt sources.

Prototype:

void

I2CMasterIntClear(unsigned long ulBase)

Parameters:


Description:

The I2C Master interrupt source is cleared, so that it no longer asserts. This must be done in the interrupt handler to keep it from being called again immediately upon exit.

Returns:

None.

9.2.2.13 I2CMasterIntDisable

Disables the I2C Master interrupt.

Prototype:

void

I2CMasterIntDisable(unsigned long ulBase)

Parameters:


Description:

Disables the I2C Master interrupt source.

120 October 11, 2007


Returns:

None.

9.2.2.14 I2CMasterIntEnable

Enables the I2C Master interrupt.

Prototype:

void

I2CMasterIntEnable(unsigned long ulBase)

Parameters:


Description:

Enables the I2C Master interrupt source.

Returns:

None.

9.2.2.15 I2CMasterIntStatus

Gets the current I2C Master interrupt status.

Prototype:

tBoolean

I2CMasterIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:


bMasked is false if the raw interrupt status is requested and true if the masked interrupt status is requested.

Description:

This returns the interrupt status for the I2C Master module. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:

The current interrupt status, returned as true if active or false if not active.

9.2.2.16 I2CMasterSlaveAddrSet

Sets the address that the I2C Master will place on the bus.

Prototype:

void

I2CMasterSlaveAddrSet(unsigned long ulBase, unsigned char ucSlaveAddr, tBoolean bReceive)

October 11, 2007 121

I2C

Parameters:


ucSlaveAddr 7-bit slave address

bReceive flag indicating the type of communication with the slave

Description:

This function will set the address that the I2C Master will place on the bus when initiating a transaction. When the parameter bReceive is set to true, the address will indicate that the

I2C Master is initiating a read from the slave; otherwise the address will indicate that the I2C

Master is initiating a write to the slave.

Returns:

None.

9.2.2.17 I2CSlaveDataGet

Receives a byte that has been sent to the I2C Slave.

Prototype:

unsigned long

I2CSlaveDataGet(unsigned long ulBase)

Parameters:

ulBase is the base address of the I2C Slave module.

Description:

This function reads a byte of data from the I2C Slave Data Register.

Returns:

Returns the byte received from by the I2C Slave, cast as an unsigned long.

9.2.2.18 I2CSlaveDataPut

Transmits a byte from the I2C Slave.

Prototype:

void

I2CSlaveDataPut(unsigned long ulBase, unsigned char ucData)

Parameters:


ucData data to be transmitted from the I2C Slave

Description:

This function will place the supplied data into I2C Slave Data Register.

Returns:

None.

122 October 11, 2007


9.2.2.19 I2CSlaveDisable

Disables the I2C slave block.

Prototype:

void

I2CSlaveDisable(unsigned long ulBase)

Parameters:


Description:

This will disable operation of the I2C slave block.

Returns:

None.

9.2.2.20 I2CSlaveEnable

Enables the I2C Slave block.

Prototype:

void

I2CSlaveEnable(unsigned long ulBase)

Parameters:


Description:

This will enable operation of the I2C Slave block.

Returns:

None.

9.2.2.21 I2CSlaveInit

Initializes the I2C Slave block.

Prototype:

void

I2CSlaveInit(unsigned long ulBase, unsigned char ucSlaveAddr)

Parameters:


ucSlaveAddr 7-bit slave address

Description:

This function initializes operation of the I2C Slave block. Upon successful initialization of the

I2C blocks, this function will have set the slave address and have enabled the I2C Slave block.

The parameter ucSlaveAddr is the value that will be compared against the slave address sent by an I2C master.

October 11, 2007 123

I2C

Returns:

None.

9.2.2.22 I2CSlaveIntClear

Clears I2C Slave interrupt sources.

Prototype:

void

I2CSlaveIntClear(unsigned long ulBase)

Parameters:


Description:

The I2C Slave interrupt source is cleared, so that it no longer asserts. This must be done in the interrupt handler to keep it from being called again immediately upon exit.

Returns:

None.

9.2.2.23 I2CSlaveIntDisable

Disables the I2C Slave interrupt.

Prototype:

void

I2CSlaveIntDisable(unsigned long ulBase)

Parameters:


Description:

Disables the I2C Slave interrupt source.

Returns:

None.

9.2.2.24 I2CSlaveIntEnable

Enables the I2C Slave interrupt.

Prototype:

void

I2CSlaveIntEnable(unsigned long ulBase)

Parameters:


Description:

Enables the I2C Slave interrupt source.

124 October 11, 2007


Returns:

None.

9.2.2.25 I2CSlaveIntStatus

Gets the current I2C Slave interrupt status.

Prototype:

tBoolean

I2CSlaveIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:


bMasked is false if the raw interrupt status is requested and true if the masked interrupt status is requested.

Description:

This returns the interrupt status for the I2C Slave module. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:

The current interrupt status, returned as

true if active or false if not active.

9.2.2.26 I2CSlaveStatus

Gets the I2C Slave module status

Prototype:

unsigned long

I2CSlaveStatus(unsigned long ulBase)

Parameters:


Description:

This function will return the action requested from a master, if any. Possible values are:

I2C_SLAVE_ACT_NONE

I2C_SLAVE_ACT_RREQ

I2C_SLAVE_ACT_TREQ

I2C_SLAVE_ACT_RREQ_FBR

Returns:

Returns I2C_SLAVE_ACT_NONE to indicate that no action has been requested of the I2C

Slave module, I2C_SLAVE_ACT_RREQ to indicate that an I2C master has sent data to the

I2C Slave module, I2C_SLAVE_ACT_TREQ to indicate that an I2C master has requested that the I2C Slave module send data, and I2C_SLAVE_ACT_RREQ_FBR to indicate that an I2C master has sent data to the I2C slave and the first byte following the slave’s own address has been received.

October 11, 2007 125

I2C

9.3


The following example shows how to use the I2C API to send data as a master.

//

// Initialize Master and Slave

//

I2CMasterInitExpClk(I2C_MASTER_BASE, SysCtlClockGet(), true);

//

// Specify slave address

//

I2CMasterSlaveAddrSet(I2C_MASTER_BASE, 0x3B, false);

//

// Place the character to be sent in the data register

//

I2CMasterDataPut(I2C_MASTER_BASE, ’Q’);

//

// Initiate send of character from Master to Slave

//

I2CMasterControl(I2C_MASTER_BASE, I2C_MASTER_CMD_SINGLE_SEND);

//

// Delay until transmission completes

// while(I2CMasterBusBusy(I2C_MASTER_BASE))

{

}

126 October 11, 2007


10 Interrupt Controller

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126


10.1

Introduction

The interrupt controller API provides a set of functions for dealing with the Nested Vectored Interrupt Controller (NVIC). Functions are provided to enable and disable interrupts, register interrupt handlers, and set the priority of interrupts.

The NVIC provides global interrupt masking, prioritization, and handler dispatching. This version of the Stellaris family supports thirty-two interrupt sources and eight priority levels. Individual interrupt sources can be masked, and the processor interrupt can be globally masked as well (without affecting the individual source masks).

The NVIC is tightly coupled with the Cortex-M3 microprocessor. When the processor responds to an interrupt, NVIC will supply the address of the function to handle the interrupt directly to the processor. This eliminates the need for a global interrupt handler that queries the interrupt controller to determine the cause of the interrupt and branch to the appropriate handler, reducing interrupt response time.

The interrupt prioritization in the NVIC allows higher priority interrupts to be handled before lower priority interrupts, as well as allowing preemption of lower priority interrupt handlers by higher priority interrupts. Again, this helps reduce interrupt response time (for example, a 1 ms system control interrupt is not held off by the execution of a lower priority 1 second housekeeping interrupt handler).

Sub-prioritization is also possible; instead of having N bits of preemptable prioritization, NVIC can be configured (via software) for N - M bits of preemptable prioritization and M bits of subpriority. In this scheme, two interrupts with the same preemptable prioritization but different subpriorities will not cause a preemption; tail chaining will instead be used to process the two interrupts back-toback.

If two interrupts with the same priority (and subpriority if so configured) are asserted at the same time, the one with the lower interrupt number will be processed first. NVIC keeps track of the nesting of interrupt handlers, allowing the processor to return from interrupt context only once all nested and pending interrupts have been handled.

Interrupt handlers can be configured in one of two ways; statically at compile time or dynamically at run time. Static configuration of interrupt handlers is accomplished by editing the interrupt handler table in the application’s startup code. When statically configured, the interrupts must be explicitly enabled in NVIC via

IntEnable()

before the processor will respond to the interrupt (in addition to any interrupt enabling required within the peripheral itself).

Alternatively, interrupts can be configured at run-time using

IntRegister()

(or the analog in each individual driver). When using

IntRegister() , the interrupt must also be enabled as before; when

using the analogue in each individual driver,

IntEnable()

is called by the driver and does not need to be call by the application.

Run-time configuration of interrupt handlers requires that the interrupt handler table be placed on a 1 kB boundary in SRAM (typically this would be at the beginning of SRAM). Failure to do so will result in an incorrect vector address being fetch in response to an interrupt. The vector table is in

October 11, 2007 127

Interrupt Controller a section called “vtable” and should be placed appropriately with a linker script. Tools that do not support linker scripts (such as the evaluation version of RV-MDK) therefore do not support run-time configuration of interrupt handlers (though the full version of RV-MDK does).

10.2

API Functions

Functions void

IntDisable

(unsigned long ulInterrupt) void

IntEnable

(unsigned long ulInterrupt) void

IntMasterDisable

(void) void

IntMasterEnable

(void) long

IntPriorityGet

(unsigned long ulInterrupt) unsigned long

IntPriorityGroupingGet

(void) void

IntPriorityGroupingSet

(unsigned long ulBits) void

IntPrioritySet

(unsigned long ulInterrupt, unsigned char ucPriority) void

IntRegister

(unsigned long ulInterrupt, void (∗pfnHandler)(void)) void

IntUnregister

(unsigned long ulInterrupt)

10.2.1


The primary function of the interrupt controller API is to manage the interrupt vector table used by the NVIC to dispatch interrupt requests. Registering an interrupt handler is a simple matter of inserting the handler address into the table. By default, the table is filled with pointers to an internal handler that loops forever; it is an error for an interrupt to occur when there is no interrupt handler registered to process it. Therefore, interrupt sources should not be enabled before a handler has been registered, and interrupt sources should be disabled before a handler is unregistered.

Interrupt handlers are managed with

IntRegister()

and

IntUnregister() .

Each interrupt source can be individually enabled and disabled via

IntEnable()

and

IntDisable() .

The processor interrupt can be enabled and disabled via

IntMasterEnable()

and

IntMasterDisable() ;

this does not affect the individual interrupt enable states. Masking of the processor interrupt can be utilized as a simple critical section (only NMI will interrupt the processor while the processor interrupt is disabled), though this will have adverse effects on the interrupt response time.

The priority of each interrupt source can be set and examined via

IntPrioritySet()

and

IntPriority-

Get() . The priority assignments are defined by the hardware; the upper N bits of the 8-bit priority

are examined to determine the priority of an interrupt (for the Stellaris family, N is 3). This allows priorities to be defined without a real need to know the exact number of supported priorities; moving to a device with more or fewer priority bits will continue to treat the interrupt source with a similar level of priority. Smaller priority numbers correspond to higher interrupt priority, so 0 is the highest priority.

128 October 11, 2007


10.2.2


10.2.2.1 IntDisable

Disables an interrupt.

Prototype:

void

IntDisable(unsigned long ulInterrupt)

Parameters:

ulInterrupt specifies the interrupt to be disabled.

Description:

The specified interrupt is disabled in the interrupt controller. Other enables for the interrupt

(such as at the peripheral level) are unaffected by this function.

Returns:

None.

10.2.2.2 IntEnable

Enables an interrupt.

Prototype:

void

IntEnable(unsigned long ulInterrupt)

Parameters:

ulInterrupt specifies the interrupt to be enabled.

Description:

The specified interrupt is enabled in the interrupt controller. Other enables for the interrupt

(such as at the peripheral level) are unaffected by this function.

Returns:

None.

10.2.2.3 IntMasterDisable

Disables the processor interrupt.

Prototype:

void

IntMasterDisable(void)

Description:

Prevents the processor from receiving interrupts. This does not affect the set of interrupts enabled in the interrupt controller; it just gates the single interrupt from the controller to the processor.

October 11, 2007 129

Interrupt Controller

Returns:

None.

10.2.2.4 IntMasterEnable

Enables the processor interrupt.

Prototype:

void

IntMasterEnable(void)

Description:

Allows the processor to respond to interrupts. This does not affect the set of interrupts enabled in the interrupt controller; it just gates the single interrupt from the controller to the processor.

Returns:

None.

10.2.2.5 IntPriorityGet

Gets the priority of an interrupt.

Prototype:

long

IntPriorityGet(unsigned long ulInterrupt)

Parameters:

ulInterrupt specifies the interrupt in question.

Description:

This function gets the priority of an interrupt. See

IntPrioritySet()

for a definition of the priority value.

Returns:

Returns the interrupt priority, or -1 if an invalid interrupt was specified.

10.2.2.6 IntPriorityGroupingGet

Gets the priority grouping of the interrupt controller.

Prototype:

unsigned long

IntPriorityGroupingGet(void)

Description:

This function returns the split between preemptable priority levels and subpriority levels in the interrupt priority specification.

Returns:

The number of bits of preemptable priority.

130 October 11, 2007


10.2.2.7 IntPriorityGroupingSet

Sets the priority grouping of the interrupt controller.

Prototype:

void

IntPriorityGroupingSet(unsigned long ulBits)

Parameters:

ulBits specifies the number of bits of preemptable priority.

Description:

This function specifies the split between preemptable priority levels and subpriority levels in the interrupt priority specification. The range of the grouping values are dependent upon the hardware implementation; on the Stellaris family, three bits are available for hardware interrupt prioritization and therefore priority grouping values of three through seven have the same effect.

Returns:

None.

10.2.2.8 IntPrioritySet

Sets the priority of an interrupt.

Prototype:

void

IntPrioritySet(unsigned long ulInterrupt, unsigned char ucPriority)

Parameters:


ucPriority specifies the priority of the interrupt.

Description:

This function is used to set the priority of an interrupt. When multiple interrupts are asserted simultaneously, the ones with the highest priority are processed before the lower priority interrupts. Smaller numbers correspond to higher interrupt priorities; priority 0 is the highest interrupt priority.

The hardware priority mechanism will only look at the upper N bits of the priority level (where

N is 3 for the Stellaris family), so any prioritization must be performed in those bits. The remaining bits can be used to sub-prioritize the interrupt sources, and may be used by the hardware priority mechanism on a future part. This arrangement allows priorities to migrate to different NVIC implementations without changing the gross prioritization of the interrupts.

Returns:

None.

10.2.2.9 IntRegister

Registers a function to be called when an interrupt occurs.

October 11, 2007 131


Prototype:

void

IntRegister(unsigned long ulInterrupt, void (*pfnHandler)(void))

Parameters:


pfnHandler is a pointer to the function to be called.

Description:

This function is used to specify the handler function to be called when the given interrupt is asserted to the processor. When the interrupt occurs, if it is enabled (via

IntEnable() ), the

handler function will be called in interrupt context. Since the handler function can preempt other code, care must be taken to protect memory or peripherals that are accessed by the handler and other non-handler code.

Note:

The use of this function (directly or indirectly via a peripheral driver interrupt register function) moves the interrupt vector table from flash to SRAM. Therefore, care must be taken when linking the application to ensure that the SRAM vector table is located at the beginning of

SRAM; otherwise NVIC will not look in the correct portion of memory for the vector table (it requires the vector table be on a 1 kB memory alignment). Normally, the SRAM vector table is so placed via the use of linker scripts; some tool chains, such as the evaluation version of

RV-MDK, do not support linker scripts and therefore will not produce a valid executable. See the discussion of compile-time versus run-time interrupt handler registration in the introduction to this chapter.

Returns:

None.

10.2.2.10 IntUnregister

Unregisters the function to be called when an interrupt occurs.

Prototype:

void

IntUnregister(unsigned long ulInterrupt)

Parameters:


Description:

This function is used to indicate that no handler should be called when the given interrupt is asserted to the processor. The interrupt source will be automatically disabled (via

IntDisable() )

if necessary.

See also:

IntRegister()


Returns:

None.

132 October 11, 2007


10.3


The following example shows how to use the Interrupt Controller API to register an interrupt handler and enable the interrupt.

//

// The interrupt handler function.

// extern void IntHandler(void);

//

// Register the interrupt handler function for interrupt 5.

//

IntRegister(5, IntHandler);

//

// Enable interrupt 5.

//

IntEnable(5);

//

// Enable interrupt 5.

//

IntMasterEnable();

October 11, 2007 133


134 October 11, 2007


11 Pulse Width Modulator

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133


11.1

Introduction

Each instance of a Stellaris PWM module provides three instances of a PWM generator block, and an output control block. Each generator block has two PWM output signals, which can be operated independently, or as a pair of signals with dead band delays inserted. Each generator block also has an interrupt output and a trigger output. The control block determines the polarity of the PWM signals, and which signals are passed through to the pins.

Some of the features of the Stellaris PWM module are:

Three generator blocks, each containing

• One 16-bit down or up/down counter

• Two comparators

• PWM generator

• Dead band generator

Control block

• PWM output enable

• Output polarity control

• Synchronization

• Fault handling

• Interrupt status

11.2

API Functions

Functions void

PWMDeadBandDisable

(unsigned long ulBase, unsigned long ulGen) void

PWMDeadBandEnable

(unsigned long ulBase, unsigned long ulGen, unsigned short us-

Rise, unsigned short usFall) void

PWMFaultIntClear


PWMFaultIntRegister

(unsigned long ulBase, void (∗pfnIntHandler)(void)) void

PWMFaultIntUnregister


PWMGenConfigure

(unsigned long ulBase, unsigned long ulGen, unsigned long ulConfig) void

PWMGenDisable


PWMGenEnable


PWMGenIntClear

(unsigned long ulBase, unsigned long ulGen, unsigned long ulInts) void

PWMGenIntRegister

(unsigned long ulBase, unsigned long ulGen, void (∗pfnInt-

Handler)(void))

October 11, 2007 135

Pulse Width Modulator unsigned long

PWMGenIntStatus

(unsigned long ulBase, unsigned long ulGen, tBoolean b-

Masked) void

PWMGenIntTrigDisable

(unsigned long ulBase, unsigned long ulGen, unsigned long ul-

IntTrig) void

PWMGenIntTrigEnable

(unsigned long ulBase, unsigned long ulGen, unsigned long ulInt-

Trig) void

PWMGenIntUnregister

(unsigned long ulBase, unsigned long ulGen) unsigned long

PWMGenPeriodGet


PWMGenPeriodSet

(unsigned long ulBase, unsigned long ulGen, unsigned long ulPeriod) void

PWMIntDisable

(unsigned long ulBase, unsigned long ulGenFault) void

PWMIntEnable

(unsigned long ulBase, unsigned long ulGenFault) unsigned long

PWMIntStatus


PWMOutputFault

(unsigned long ulBase, unsigned long ulPWMOutBits, tBoolean bFault-

Kill) void

PWMOutputInvert

(unsigned long ulBase, unsigned long ulPWMOutBits, tBoolean b-

Invert) void

PWMOutputState

(unsigned long ulBase, unsigned long ulPWMOutBits, tBoolean b-

Enable) unsigned long

PWMPulseWidthGet

(unsigned long ulBase, unsigned long ulPWMOut) void

PWMPulseWidthSet

(unsigned long ulBase, unsigned long ulPWMOut, unsigned long ulWidth) void

PWMSyncTimeBase

(unsigned long ulBase, unsigned long ulGenBits) void

PWMSyncUpdate

(unsigned long ulBase, unsigned long ulGenBits)

11.2.1


These are a group of functions for performing high-level operations on PWM modules. Although

Stellaris only has one PWM module, these functions are defined to support using multiple instances of PWM modules.

The following functions provide the user with a way to configure the PWM for the most common operations, such as setting the period, generating left and center aligned pulses, modifying the pulse width, and controlling interrupts, triggers, and output characteristics. However, the PWM module is very versatile, and it can be configured in a number of different ways, many of which are beyond the scope of this API. In order to fully exploit the many features of the PWM module, users are advised to use register access macros.

When discussing the various components of a PWM module, this API uses the following labeling convention:

The three generator blocks are called Gen0, Gen1, and Gen2.

The two PWM output signals associated with each generator block are called OutA and OutB.

The six output signals are called PWM0, PWM1, PWM2, PWM3, PWM4, and PWM5.

PWM0 and PWM1 are associated with Gen0, PWM2 and PWM3 are associated with Gen1, and PWM4 and PWM5 are associated with Gen2.

Also, as a simplifying assumption for this API, comparator A for each generator block is used exclusively to adjust the pulse width of the even numbered PWM outputs ( PWM0, PWM2, and PWM4).

In addition, comparator B is used exclusively for the odd numbered PWM outputs ( PWM1, PWM3,

PWM5).

136 October 11, 2007


11.2.2


11.2.2.1 PWMDeadBandDisable

Disables the PWM dead band output.

Prototype:

void

PWMDeadBandDisable(unsigned long ulBase, unsigned long ulGen)

Parameters:

ulBase is the base address of the PWM module.

ulGen is the PWM generator to modify. Must be one of PWM_GEN_0, PWM_GEN_1, or

PWM_GEN_2.

Description:

This function disables the dead band mode for the specified PWM generator. Doing so decouples the OutA and OutB signals.

Returns:

None.

11.2.2.2 PWMDeadBandEnable

Enables the PWM dead band output, and sets the dead band delays.

Prototype:

void

PWMDeadBandEnable(unsigned long ulBase, unsigned long ulGen, unsigned short usRise, unsigned short usFall)

Parameters:


ulGen is the PWM generator to modify. Must be one of PWM_GEN_0, PWM_GEN_1, or

PWM_GEN_2.

usRise specifies the width of delay from the rising edge.

usFall specifies the width of delay from the falling edge.

Description:

This function sets the dead bands for the specified PWM generator, where the dead bands are defined as the number of PWM clock ticks from the rising or falling edge of the generator’s

OutA signal. Note that this function causes the coupling of OutB to OutA.

Returns:

None.

October 11, 2007 137

Pulse Width Modulator

11.2.2.3 PWMFaultIntClear

Clears the fault interrupt for a PWM module.

Prototype:

void

PWMFaultIntClear(unsigned long ulBase)

Parameters:


Description:

Clears the fault interrupt by writing to the appropriate bit of the interrupt status register for the selected PWM module.

Returns:

None.

11.2.2.4 PWMFaultIntRegister

Registers an interrupt handler for a fault condition detected in a PWM module.

Prototype:

void

PWMFaultIntRegister(unsigned long ulBase, void (*pfnIntHandler)(void))

Parameters:


pfnIntHandler is a pointer to the function to be called when the PWM fault interrupt occurs.

Description:

This function will ensure that the interrupt handler specified by pfnIntHandler is called when a fault interrupt is detected for the selected PWM module. This function will also enable the

PWM fault interrupt in the NVIC; the PWM fault interrupt must also be enabled at the module level using

PWMIntEnable() .

See also:

IntRegister()


Returns:

None.

11.2.2.5 PWMFaultIntUnregister

Removes the PWM fault condition interrupt handler.

Prototype:

void

PWMFaultIntUnregister(unsigned long ulBase)

138 October 11, 2007


Parameters:


Description:

This function will remove the interrupt handler for a PWM fault interrupt from the selected PWM module. This function will also disable the PWM fault interrupt in the NVIC; the PWM fault interrupt must also be disabled at the module level using

PWMIntDisable() .

See also:

IntRegister()


Returns:

None.

11.2.2.6 PWMGenConfigure

Configures a PWM generator.

Prototype:

void

PWMGenConfigure(unsigned long ulBase, unsigned long ulGen, unsigned long ulConfig)

Parameters:


ulGen is the PWM generator to configure. Must be one of PWM_GEN_0, PWM_GEN_1, or

PWM_GEN_2.

ulConfig is the configuration for the PWM generator.

Description:

This function is used to set the mode of operation for a PWM generator. The counting mode, synchronization mode, and debug behavior are all configured. After configuration, the generator is left in the disabled state.

A PWM generator can count in two different modes: count down mode or count up/down mode. In count down mode, it will count from a value down to zero, and then reset to the preset value. This will produce left-aligned PWM signals (i.e. the rising edge of the two PWM signals produced by the generator will occur at the same time). In count up/down mode, it will count up from zero to the preset value, count back down to zero, and then repeat the process. This will produce center-aligned PWM signals (i.e. the middle of the high/low period of the PWM signals produced by the generator will occur at the same time).

When the PWM generator parameters (period and pulse width) are modified, their affect on the output PWM signals can be delayed. In synchronous mode, the parameter updates are not applied until a synchronization event occurs. This allows multiple parameters to be modified and take affect simultaneously, instead of one at a time. Additionally, parameters to multiple

PWM generators in synchronous mode can be updated simultaneously, allowing them to be treated as if they were a unified generator. In non-synchronous mode, the parameter updates are not delayed until a synchronization event. In either mode, the parameter updates only occur when the counter is at zero to help prevent oddly formed PWM signals during the update

(i.e. a PWM pulse that is too short or too long).

October 11, 2007 139


The PWM generator can either pause or continue running when the processor is stopped via the debugger. If configured to pause, it will continue to count until it reaches zero, at which point it will pause until the processor is restarted. If configured to continue running, it will keep counting as if nothing had happened.

The ulConfig parameter contains the desired configuration. It is the logical OR of the following:

PWM_GEN_MODE_DOWN or PWM_GEN_MODE_UP_DOWN to specify the counting mode,

PWM_GEN_MODE_SYNC or PWM_GEN_MODE_NO_SYNC to specify the synchronization mode, and PWM_GEN_MODE_DBG_RUN or PWM_GEN_MODE_DBG_STOP to specify the debug behavior.

Note:

Changes to the counter mode will affect the period of the PWM signals produced.

PWMGen-

PeriodSet()

and

PWMPulseWidthSet()

should be called after any changes to the counter mode of a generator.

Returns:

None.

11.2.2.7 PWMGenDisable

Disables the timer/counter for a PWM generator block.

Prototype:

void

PWMGenDisable(unsigned long ulBase, unsigned long ulGen)

Parameters:


ulGen is the PWM generator to be disabled. Must be one of PWM_GEN_0, PWM_GEN_1, or

PWM_GEN_2.

Description:

This function blocks the PWM clock from driving the timer/counter for the specified generator block.

Returns:

None.

11.2.2.8 PWMGenEnable

Enables the timer/counter for a PWM generator block.

Prototype:

void

PWMGenEnable(unsigned long ulBase, unsigned long ulGen)

Parameters:


140 October 11, 2007


ulGen is the PWM generator to be enabled. Must be one of PWM_GEN_0, PWM_GEN_1, or

PWM_GEN_2.

Description:

This function allows the PWM clock to drive the timer/counter for the specified generator block.

Returns:

None.

11.2.2.9 PWMGenIntClear

Clears the specified interrupt(s) for the specified PWM generator block.

Prototype:

void

PWMGenIntClear(unsigned long ulBase, unsigned long ulGen, unsigned long ulInts)

Parameters:


ulGen is the PWM generator to query. Must be one of PWM_GEN_0, PWM_GEN_1, or

PWM_GEN_2.

ulInts specifies the interrupts to be cleared.

Description:

Clears the specified interrupt(s) by writing a 1 to the specified bits of the interrupt status register for the specified PWM generator. The defined values for the bits are as follows:

PWM_INT_CNT_ZERO

PWM_INT_CNT_LOAD

PWM_INT_CNT_AU

PWM_INT_CNT_AD

PWM_INT_CNT_BU

PWM_INT_CNT_BD

Returns:

None.

11.2.2.10 PWMGenIntRegister

Registers an interrupt handler for the specified PWM generator block.

Prototype:

void

PWMGenIntRegister(unsigned long ulBase, unsigned long ulGen, void (*pfnIntHandler)(void))

October 11, 2007 141


Parameters:


ulGen is the PWM generator in question.

pfnIntHandler is a pointer to the function to be called when the PWM generator interrupt occurs.

Description:

This function will ensure that the interrupt handler specified by pfnIntHandler is called when an interrupt is detected for the specified PWM generator block. This function will also enable the corresponding PWM generator interrupt in the interrupt controller; individual generator interrupts and interrupt sources must be enabled with

PWMIntEnable()

and

PWMGenIntTrig-

Enable() .

See also:

IntRegister()


Returns:

None.

11.2.2.11 PWMGenIntStatus

Gets interrupt status for the specified PWM generator block.

Prototype:

unsigned long

PWMGenIntStatus(unsigned long ulBase, unsigned long ulGen, tBoolean bMasked)

Parameters:



PWM_GEN_2.


Description:

If bMasked is set as true, then the masked interrupt status is returned; otherwise, the raw interrupt status will be returned.

Returns:

Returns the contents of the interrupt status register, or the contents of the raw interrupt status register, for the specified PWM generator.

11.2.2.12 PWMGenIntTrigDisable

Disables interrupts for the specified PWM generator block.

Prototype:

void

PWMGenIntTrigDisable(unsigned long ulBase, unsigned long ulGen, unsigned long ulIntTrig)

142 October 11, 2007


Parameters:


ulGen is the PWM generator to have interrupts and triggers disabled. Must be one of PWM_-

GEN_0, PWM_GEN_1, or PWM_GEN_2.

ulIntTrig specifies the interrupts and triggers to be disabled.

Description:

Masks the specified interrupt(s) and trigger(s) by clearing the specified bits of the interrupt/trigger enable register for the specified PWM generator. The defined values for the bits are as follows:

PWM_INT_CNT_ZERO

PWM_INT_CNT_LOAD

PWM_INT_CNT_AU

PWM_INT_CNT_AD

PWM_INT_CNT_BU

PWM_INT_CNT_BD

PWM_TR_CNT_ZERO

PWM_TR_CNT_LOAD

PWM_TR_CNT_AU

PWM_TR_CNT_AD

PWM_TR_CNT_BU

PWM_TR_CNT_BD

Returns:

None.

11.2.2.13 PWMGenIntTrigEnable

Enables interrupts and triggers for the specified PWM generator block.

Prototype:

void

PWMGenIntTrigEnable(unsigned long ulBase, unsigned long ulGen, unsigned long ulIntTrig)

Parameters:


ulGen is the PWM generator to have interrupts and triggers enabled. Must be one of PWM_-

GEN_0, PWM_GEN_1, or PWM_GEN_2.

ulIntTrig specifies the interrupts and triggers to be enabled.

Description:

Unmasks the specified interrupt(s) and trigger(s) by setting the specified bits of the interrupt/trigger enable register for the specified PWM generator. The defined values for the bits are as follows:

PWM_INT_CNT_ZERO

PWM_INT_CNT_LOAD

October 11, 2007 143


PWM_INT_CNT_AU

PWM_INT_CNT_AD

PWM_INT_CNT_BU

PWM_INT_CNT_BD

PWM_TR_CNT_ZERO

PWM_TR_CNT_LOAD

PWM_TR_CNT_AU

PWM_TR_CNT_AD

PWM_TR_CNT_BU

PWM_TR_CNT_BD

Returns:

None.

11.2.2.14 PWMGenIntUnregister

Removes an interrupt handler for the specified PWM generator block.

Prototype:

void

PWMGenIntUnregister(unsigned long ulBase, unsigned long ulGen)

Parameters:


ulGen is the PWM generator in question.

Description:

This function will unregister the interrupt handler for the specified PWM generator block. This function will also disable the corresponding PWM generator interrupt in the interrupt controller; individual generator interrupts and interrupt sources must be disabled with

PWMIntDisable()

and

PWMGenIntTrigDisable() .

See also:

IntRegister()


Returns:

None.

11.2.2.15 PWMGenPeriodGet

Gets the period of a PWM generator block.

Prototype:

unsigned long

PWMGenPeriodGet(unsigned long ulBase, unsigned long ulGen)

Parameters:


144 October 11, 2007



PWM_GEN_2.

Description:

This function gets the period of the specified PWM generator block. The period of the generator block is defined as the number of PWM clock ticks between pulses on the generator block zero signal.

If the update of the counter for the specified PWM generator has yet to be completed, the value returned may not be the active period. The value returned is the programmed period, measured in PWM clock ticks.

Returns:

Returns the programmed period of the specified generator block in PWM clock ticks.

11.2.2.16 PWMGenPeriodSet

Set the period of a PWM generator.

Prototype:

void

PWMGenPeriodSet(unsigned long ulBase, unsigned long ulGen, unsigned long ulPeriod)

Parameters:


ulGen is the PWM generator to be modified. Must be one of PWM_GEN_0, PWM_GEN_1, or

PWM_GEN_2.

ulPeriod specifies the period of PWM generator output, measured in clock ticks.

Description:

This function sets the period of the specified PWM generator block, where the period of the generator block is defined as the number of

PWM clock ticks between pulses on the generator block zero signal.

Note:

Any subsequent calls made to this function before an update occurs will cause the previous values to be overwritten.

Returns:

None.

11.2.2.17 PWMIntDisable

Disables generator and fault interrupts for a PWM module.

Prototype:

void

PWMIntDisable(unsigned long ulBase, unsigned long ulGenFault)

October 11, 2007 145


Parameters:


ulGenFault contains the interrupts to be disabled. Must be a logical OR of any of PWM_INT_-

GEN_0, PWM_INT_GEN_1, PWM_INT_GEN_2, or PWM_INT_FAULT.

Description:

Masks the specified interrupt(s) by clearing the specified bits of the interrupt enable register for the selected PWM module.

Returns:

None.

11.2.2.18 PWMIntEnable

Enables generator and fault interrupts for a PWM module.

Prototype:

void

PWMIntEnable(unsigned long ulBase, unsigned long ulGenFault)

Parameters:


ulGenFault contains the interrupts to be enabled. Must be a logical OR of any of PWM_INT_-

GEN_0, PWM_INT_GEN_1, PWM_INT_GEN_2, or PWM_INT_FAULT.

Description:

Unmasks the specified interrupt(s) by setting the specified bits of the interrupt enable register for the selected PWM module.

Returns:

None.

11.2.2.19 PWMIntStatus

Gets the interrupt status for a PWM module.

Prototype:

unsigned long

PWMIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:



Description:

If bMasked is set as true, then the masked interrupt status is returned; otherwise, the raw interrupt status will be returned.

Returns:

The current interrupt status, enumerated as a bit field of PWM_INT_GEN_0, PWM_INT_GEN_-

1, PWM_INT_GEN_2, and PWM_INT_FAULT.

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11.2.2.20 PWMOutputFault

Specifies the state of PWM outputs in response to a fault condition.

Prototype:

void

PWMOutputFault(unsigned long ulBase, unsigned long ulPWMOutBits, tBoolean bFaultKill)

Parameters:


ulPWMOutBits are the PWM outputs to be modified.

Must be the logical OR of any of

PWM_OUT_0_BIT, PWM_OUT_1_BIT, PWM_OUT_2_BIT, PWM_OUT_3_BIT, PWM_-

OUT_4_BIT, or PWM_OUT_5_BIT.

bFaultKill determines if the signal is killed or passed through during an active fault condition.

Description:

This function sets the fault handling characteristics of the selected PWM outputs. The outputs are selected using the parameter ulPWMOutBits. The parameter bFaultKill determines the fault handling characteristics for the selected outputs. If bFaultKill is true, then the selected outputs will be made inactive. If bFaultKill is

false, then the selected outputs are unaffected by the detected fault.

Returns:

None.

11.2.2.21 PWMOutputInvert

Selects the inversion mode for PWM outputs.

Prototype:

void

PWMOutputInvert(unsigned long ulBase, unsigned long ulPWMOutBits, tBoolean bInvert)

Parameters:






bInvert determines if the signal is inverted or passed through.

Description:

This function is used to select the inversion mode for the selected PWM outputs. The outputs are selected using the parameter ulPWMOutBits. The parameter bInvert determines the inversion mode for the selected outputs. If bInvert is true, this function will cause the specified

PWM output signals to be inverted, or made active low. If bInvert is false, the specified output will be passed through as is, or be made active high.

Returns:

None.

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11.2.2.22 PWMOutputState

Enables or disables PWM outputs.

Prototype:

void

PWMOutputState(unsigned long ulBase, unsigned long ulPWMOutBits, tBoolean bEnable)

Parameters:






bEnable determines if the signal is enabled or disabled.

Description:

This function is used to enable or disable the selected PWM outputs. The outputs are selected using the parameter ulPWMOutBits. The parameter bEnable determines the state of the selected outputs. If bEnable is

true, then the selected PWM outputs are enabled, or placed in the active state. If bEnable is false, then the selected outputs are disabled, or placed in the inactive state.

Returns:

None.

11.2.2.23 PWMPulseWidthGet

Gets the pulse width of a PWM output.

Prototype:

unsigned long

PWMPulseWidthGet(unsigned long ulBase, unsigned long ulPWMOut)

Parameters:


ulPWMOut is the PWM output to query. Must be one of PWM_OUT_0, PWM_OUT_1, PWM_-

OUT_2, PWM_OUT_3, PWM_OUT_4, or PWM_OUT_5.

Description:

This function gets the currently programmed pulse width for the specified PWM output. If the update of the comparator for the specified output has yet to be completed, the value returned may not be the active pulse width. The value returned is the programmed pulse width, measured in PWM clock ticks.

Returns:

Returns the width of the pulse in PWM clock ticks.

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11.2.2.24 PWMPulseWidthSet

Sets the pulse width for the specified PWM output.

Prototype:

void

PWMPulseWidthSet(unsigned long ulBase, unsigned long ulPWMOut, unsigned long ulWidth)

Parameters:


ulPWMOut is the PWM output to modify.

Must be one of PWM_OUT_0, PWM_OUT_1,

PWM_OUT_2, PWM_OUT_3, PWM_OUT_4, or PWM_OUT_5.

ulWidth specifies the width of the positive portion of the pulse.

Description:

This function sets the pulse width for the specified PWM output, where the pulse width is defined as the number of PWM clock ticks.

Note:

Any subsequent calls made to this function before an update occurs will cause the previous values to be overwritten.

Returns:

None.

11.2.2.25 PWMSyncTimeBase

Synchronizes the counters in one or multiple PWM generator blocks.

Prototype:

void

PWMSyncTimeBase(unsigned long ulBase, unsigned long ulGenBits)

Parameters:


ulGenBits are the PWM generator blocks to be synchronized. Must be the logical OR of any of PWM_GEN_0_BIT, PWM_GEN_1_BIT, or PWM_GEN_2_BIT.

Description:

For the selected PWM module, this function synchronizes the time base of the generator blocks by causing the specified generator counters to be reset to zero.

Returns:

None.

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11.2.2.26 PWMSyncUpdate

Synchronizes all pending updates.

Prototype:

void

PWMSyncUpdate(unsigned long ulBase, unsigned long ulGenBits)

Parameters:


ulGenBits are the PWM generator blocks to be updated. Must be the logical OR of any of

PWM_GEN_0_BIT, PWM_GEN_1_BIT, or PWM_GEN_2_BIT.

Description:

For the selected PWM generators, this function causes all queued updates to the period or pulse width to be applied the next time the corresponding counter becomes zero.

Returns:

None.

11.3


The following example shows how to use the PWM API to initialize the PWM0 with a 50 KHz frequency, and with a 25% duty cycle on

PWM0 and a 75% duty cycle on PWM1.

//

// Configure the PWM generator for count down mode with immediate updates

// to the parameters.

//

PWMGenConfigure(PWM_BASE, PWM_GEN_0,

PWM_GEN_MODE_DOWN | PWM_GEN_MODE_NO_SYNC);

//

// Set the period.

For a 50 KHz frequency, the period = 1/50,000, or 20

// microseconds.

For a 20 MHz clock, this translates to 400 clock ticks.

// Use this value to set the period.

//

PWMGenPeriodSet(PWM_BASE, PWM_GEN_0, 400);

//

// Set the pulse width of PWM0 for a 25% duty cycle.

//

PWMPulseWidthSet(PWM_BASE, PWM_OUT_0, 100);

//

// Set the pulse width of PWM1 for a 75% duty cycle.

//

PWMPulseWidthSet(PWM_BASE, PWM_OUT_1, 300);

//

// Start the timers in generator 0.

//

PWMGenEnable(PWM_BASE, PWM_GEN_0);

//

// Enable the outputs.

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//

PWMOutputState(PWM_BASE, (PWM_OUT_0_BIT | PWM_OUT_1_BIT), true);

October 11, 2007 151


152 October 11, 2007


12 Quadrature Encoder

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151


12.1

Introduction

The quadrature encoder API provides a set of functions for dealing with the Quadrature Encoder with Index (QEI). Functions are provided to configure and read the position and velocity captures, register a QEI interrupt handler, and handle QEI interrupt masking/clearing.

The quadrature encoder module provides hardware encoding of the two channels and the index signal from a quadrature encoder device into an absolute or relative position. There is additional hardware for capturing a measure of the encoder velocity, which is simply a count of encoder pulses during a fixed time period; the number of pulses is directly proportional to the encoder speed. Note that the velocity capture can only operate when the position capture is enabled.

The QEI module supports two modes of operation: phase mode and clock/direction mode. In phase mode, the encoder produces two clocks that are 90 degrees out of phase; the edge relationship is used to determine the direction of rotation. In clock/direction mode, the encoder produces a clock signal to indicate steps and a direction signal to indicate the direction of rotation.

When in phase mode, edges on the first channel or edges on both channels can be counted; counting edges on both channels provides higher encoder resolution if required. In either mode, the input signals can be swapped before being processed; this allows wiring mistakes on the circuit board to be corrected without modifying the board.

The index pulse can be used to reset the position counter; this causes the position counter to maintain the absolute encoder position. Otherwise, the position counter maintains the relative position and is never reset.

The velocity capture has a timer to measure equal periods of time. The number of encoder pulses over each time period is accumulated as a measure of the encoder velocity. The running total for the current time period and the final count for the previous time period are available to be read. The final count for the previous time period is usually used as the velocity measure.

The QEI module will generate interrupts when the index pulse is detected, when the velocity timer expires, when the encoder direction changes, and when a phase signal error is detected. These interrupt sources can be individually masked so that only the events of interest cause a processor interrupt.

12.2

API Functions

Functions void

QEIConfigure

(unsigned long ulBase, unsigned long ulConfig, unsigned long ulMax-

Position) long

QEIDirectionGet


QEIDisable


October 11, 2007 153

Quadrature Encoder void

QEIEnable


QEIErrorGet


QEIIntClear


QEIIntDisable


QEIIntEnable


QEIIntRegister


QEIIntStatus


QEIIntUnregister


QEIPositionGet


QEIPositionSet

(unsigned long ulBase, unsigned long ulPosition) void

QEIVelocityConfigure

(unsigned long ulBase, unsigned long ulPreDiv, unsigned long ul-

Period) void

QEIVelocityDisable


QEIVelocityEnable


QEIVelocityGet


12.2.1


The quadrature encoder API is broken into three groups of functions: those that deal with position capture, those that deal with velocity capture, and those that deal with interrupt handling.

The position capture is managed with

QEIEnable() ,

QEIDisable() ,

QEIConfigure() , and

QEIPosition-

Set() .

The positional information is retrieved with

QEIPositionGet() ,

QEIDirectionGet() , and

QEIErrorGet() .

The velocity capture is managed with

QEIVelocityEnable() ,

QEIVelocityDisable() , and QEIVelocity-

Configure() . The computed encoder velocity is retrieved with

QEIVelocityGet() .

The interrupt handler for the QEI interrupt is managed with

QEIIntRegister()

and

QEIIntUnregister() .

The individual interrupt sources within the QEI module are managed with

QEIIntEnable() , QEIInt-

Disable() ,

QEIIntStatus() , and

QEIIntClear() .

12.2.2


12.2.2.1 QEIConfigure

Configures the quadrature encoder.

Prototype:

void

QEIConfigure(unsigned long ulBase, unsigned long ulConfig, unsigned long ulMaxPosition)

Parameters:

ulBase is the base address of the quadrature encoder module.

ulConfig is the configuration for the quadrature encoder. See below for a description of this parameter.

ulMaxPosition specifies the maximum position value.

154 October 11, 2007


Description:

This will configure the operation of the quadrature encoder. The ulConfig parameter provides the configuration of the encoder and is the logical OR of several values:

QEI_CONFIG_CAPTURE_A or QEI_CONFIG_CAPTURE_A_B to specify if edges on channel A or on both channels A and B should be counted by the position integrator and velocity accumulator.

QEI_CONFIG_NO_RESET or QEI_CONFIG_RESET_IDX to specify if the position integrator should be reset when the index pulse is detected.

QEI_CONFIG_QUADRATURE or QEI_CONFIG_CLOCK_DIR to specify if quadrature signals are being provided on ChA and ChB, or if a direction signal and a clock are being provided instead.

QEI_CONFIG_NO_SWAP or QEI_CONFIG_SWAP to specify if the signals provided on

ChA and ChB should be swapped before being processed.

ulMaxPosition is the maximum value of the position integrator, and is the value used to reset the position capture when in index reset mode and moving in the reverse (negative) direction.

Returns:

None.

12.2.2.2 QEIDirectionGet

Gets the current direction of rotation.

Prototype:

long

QEIDirectionGet(unsigned long ulBase)

Parameters:


Description:

This returns the current direction of rotation. In this case, current means the most recently detected direction of the encoder; it may not be presently moving but this is the direction it last moved before it stopped.

Returns:

1 if moving in the forward direction or -1 if moving in the reverse direction.

12.2.2.3 QEIDisable

Disables the quadrature encoder.

Prototype:

void

QEIDisable(unsigned long ulBase)

Parameters:


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Quadrature Encoder

Description:

This will disable operation of the quadrature encoder module.

Returns:

None.

12.2.2.4 QEIEnable

Enables the quadrature encoder.

Prototype:

void

QEIEnable(unsigned long ulBase)

Parameters:


Description:

This will enable operation of the quadrature encoder module. It must be configured before it is enabled.

See also:

QEIConfigure()

Returns:

None.

12.2.2.5 QEIErrorGet

Gets the encoder error indicator.

Prototype:

tBoolean

QEIErrorGet(unsigned long ulBase)

Parameters:


Description:

This returns the error indicator for the quadrature encoder. It is an error for both of the signals of the quadrature input to change at the same time.

Returns:

true if an error has occurred and false otherwise.

12.2.2.6 QEIIntClear

Clears quadrature encoder interrupt sources.

156 October 11, 2007


Prototype:

void

QEIIntClear(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:


ulIntFlags is a bit mask of the interrupt sources to be cleared. Can be any of the QEI_-

INTERROR, QEI_INTDIR, QEI_INTTIMER, or QEI_INTINDEX values.

Description:

The specified quadrature encoder interrupt sources are cleared, so that they no longer assert.

This must be done in the interrupt handler to keep it from being called again immediately upon exit.

Returns:

None.

12.2.2.7 QEIIntDisable

Disables individual quadrature encoder interrupt sources.

Prototype:

void

QEIIntDisable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:


ulIntFlags is a bit mask of the interrupt sources to be disabled. Can be any of the QEI_-


Description:

Disables the indicated quadrature encoder interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.

Returns:

None.

12.2.2.8 QEIIntEnable

Enables individual quadrature encoder interrupt sources.

Prototype:

void

QEIIntEnable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:


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Quadrature Encoder

ulIntFlags is a bit mask of the interrupt sources to be enabled. Can be any of the QEI_-


Description:

Enables the indicated quadrature encoder interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.

Returns:

None.

12.2.2.9 QEIIntRegister

Registers an interrupt handler for the quadrature encoder interrupt.

Prototype:

void

QEIIntRegister(unsigned long ulBase, void (*pfnHandler)(void))

Parameters:


pfnHandler is a pointer to the function to be called when the quadrature encoder interrupt occurs.

Description:

This sets the handler to be called when a quadrature encoder interrupt occurs. This will enable the global interrupt in the interrupt controller; specific quadrature encoder interrupts must be enabled via

QEIIntEnable() . It is the interrupt handler’s responsibility to clear the interrupt

source via

QEIIntClear() .

See also:

IntRegister()


Returns:

None.

12.2.2.10 QEIIntStatus


Prototype:

unsigned long

QEIIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:



158 October 11, 2007


Description:

This returns the interrupt status for the quadrature encoder module. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:

The current interrupt status, enumerated as a bit field of QEI_INTERROR, QEI_INTDIR, QEI_-

INTTIMER, and QEI_INTINDEX.

12.2.2.11 QEIIntUnregister

Unregisters an interrupt handler for the quadrature encoder interrupt.

Prototype:

void

QEIIntUnregister(unsigned long ulBase)

Parameters:


Description:

This function will clear the handler to be called when a quadrature encoder interrupt occurs.

This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

See also:

IntRegister()


Returns:

None.

12.2.2.12 QEIPositionGet

Gets the current encoder position.

Prototype:

unsigned long

QEIPositionGet(unsigned long ulBase)

Parameters:


Description:

This returns the current position of the encoder. Depending upon the configuration of the encoder, and the incident of an index pulse, this value may or may not contain the expected data (i.e. if in reset on index mode, if an index pulse has not been encountered, the position counter will not be aligned with the index pulse yet).

Returns:

The current position of the encoder.

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Quadrature Encoder

12.2.2.13 QEIPositionSet

Sets the current encoder position.

Prototype:

void

QEIPositionSet(unsigned long ulBase, unsigned long ulPosition)

Parameters:


ulPosition is the new position for the encoder.

Description:

This sets the current position of the encoder; the encoder position will then be measured relative to this value.

Returns:

None.

12.2.2.14 QEIVelocityConfigure

Configures the velocity capture.

Prototype:

void

QEIVelocityConfigure(unsigned long ulBase, unsigned long ulPreDiv, unsigned long ulPeriod)

Parameters:


ulPreDiv specifies the predivider applied to the input quadrature signal before it is counted; can be one of QEI_VELDIV_1, QEI_VELDIV_2, QEI_VELDIV_4, QEI_VELDIV_8, QEI_-

VELDIV_16, QEI_VELDIV_32, QEI_VELDIV_64, or QEI_VELDIV_128.

ulPeriod specifies the number of clock ticks over which to measure the velocity; must be nonzero.

Description:

This will configure the operation of the velocity capture portion of the quadrature encoder. The position increment signal is predivided as specified by ulPreDiv before being accumulated by the velocity capture. The divided signal is accumulated over ulPeriod system clock before being saved and resetting the accumulator.

Returns:

None.

12.2.2.15 QEIVelocityDisable

Disables the velocity capture.

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Prototype:

void

QEIVelocityDisable(unsigned long ulBase)

Parameters:


Description:

This will disable operation of the velocity capture in the quadrature encoder module.

Returns:

None.

12.2.2.16 QEIVelocityEnable

Enables the velocity capture.

Prototype:

void

QEIVelocityEnable(unsigned long ulBase)

Parameters:


Description:

This will enable operation of the velocity capture in the quadrature encoder module. It must be configured before it is enabled. Velocity capture will not occur if the quadrature encoder is not enabled.

See also:

QEIVelocityConfigure()

and

QEIEnable()

Returns:

None.

12.2.2.17 QEIVelocityGet

Gets the current encoder speed.

Prototype:

unsigned long

QEIVelocityGet(unsigned long ulBase)

Parameters:


Description:

This returns the current speed of the encoder. The value returned is the number of pulses detected in the specified time period; this number can be multiplied by the number of time periods per second and divided by the number of pulses per revolution to obtain the number of revolutions per second.

October 11, 2007 161

Quadrature Encoder

Returns:

The number of pulses captured in the given time period.

12.3


The following example shows how to use the Quadrature Encoder API to configure the quadrature encoder read back an absolute position.

//

// Configure the quadrature encoder to capture edges on both signals and

// maintain an absolute position by resetting on index pulses.

Using a

// 1000 line encoder at four edges per line, there are 4000 pulses per

// revolution; therefore set the maximum position to 3999 since the count

// is zero based.

//

QEIConfigure(QEI_BASE, (QEI_CONFIG_CAPTURE_A_B | QEI_CONFIG_RESET_IDX |

QEI_CONFIG_QUADRATURE | QEI_CONFIG_NO_SWAP), 3999);

//

// Enable the quadrature encoder.

//

QEIEnable(QEI_BASE);

//


//

//

// Read the encoder position.

//

QEIPositionGet(QEI_BASE);

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13 Synchronous Serial Interface

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161


13.1

Introduction

The Synchronous Serial Interface (SSI) module provides the functionality for synchronous serial communications with peripheral devices, and can be configured to use either the Motorola® SPI™,

National Semiconductor® Microwire, or the Texas Instruments® synchronous serial interface frame formats. The size of the data frame is also configurable, and can be set to be between 4 and 16 bits, inclusive.

The SSI module performs serial-to-parallel data conversion on data received from a peripheral device, and parallel-to-serial conversion on data transmitted to a peripheral device. The TX and RX paths are buffered with internal FIFOs allowing up to eight 16-bit values to be stored independently.

The SSI module can be configured as either a master or a slave device. As a slave device, the SSI module can also be configured to disable its output, which allows a master device to be coupled with multiple slave devices.

The SSI module also includes a programmable bit rate clock divider and prescaler to generate the output serial clock derived from the SSI module’s input clock. Bit rates are generated based on the input clock and the maximum bit rate supported by the connected peripheral.

13.2

API Functions

Functions void

SSIConfigSetExpClk

(unsigned long ulBase, unsigned long ulSSIClk, unsigned long ul-

Protocol, unsigned long ulMode, unsigned long ulBitRate, unsigned long ulDataWidth) void

SSIDataGet

(unsigned long ulBase, unsigned long ∗pulData) long

SSIDataGetNonBlocking

(unsigned long ulBase, unsigned long ∗pulData) void

SSIDataPut

(unsigned long ulBase, unsigned long ulData) long

SSIDataPutNonBlocking

(unsigned long ulBase, unsigned long ulData) void

SSIDisable


SSIEnable


SSIIntClear


SSIIntDisable


SSIIntEnable


SSIIntRegister


SSIIntStatus


SSIIntUnregister


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Synchronous Serial Interface

13.2.1


The SSI API is broken into 3 groups of functions: those that deal with configuration and state, those that handle data, and those that manage interrupts.

The configuration of the SSI module is managed by the

SSIConfigSetExpClk()

function, while state is managed by the

SSIEnable()

and

SSIDisable()

functions.

Data handling is performed by the

SSIDataPut() , SSIDataPutNonBlocking() ,

SSIDataGet() , and

SSIDataGetNonBlocking()

functions.

Interrupts from the SSI module are managed using the

SSIIntClear() , SSIIntDisable() , SSIInt-

Enable() ,

SSIIntRegister() , SSIIntStatus() , and

SSIIntUnregister()

functions.

The SSIConfig(), SSIDataNonBlockingGet(), and SSIDataNonBlockingPut() APIs from previous versions of the Peripheral Driver Library have been replaced by the

SSIConfigSetExpClk() ,

SSIDataGetNonBlocking() , and

SSIDataPutNonBlocking()

APIs. Macros have been provided in ssi.h

to map the old APIs to the new APIs, allowing existing applications to link and run with the new APIs. It is recommended that new applications utilize the new APIs in favor of the old ones.

13.2.2


13.2.2.1 SSIConfigSetExpClk

Configures the synchronous serial interface.

Prototype:

void

SSIConfigSetExpClk(unsigned long ulBase, unsigned long ulSSIClk, unsigned long ulProtocol, unsigned long ulMode, unsigned long ulBitRate, unsigned long ulDataWidth)

Parameters:

ulBase specifies the SSI module base address.

ulSSIClk is the rate of the clock supplied to the SSI module.

ulProtocol specifies the data transfer protocol.

ulMode specifies the mode of operation.

ulBitRate specifies the clock rate.

ulDataWidth specifies number of bits transfered per frame.

Description:

This function configures the synchronous serial interface. It sets the SSI protocol, mode of operation, bit rate, and data width.

The parameter ulProtocol defines the data frame format. The parameter ulProtocol can be one of the following values: SSI_FRF_MOTO_MODE_0, SSI_FRF_MOTO_MODE_1, SSI_-

FRF_MOTO_MODE_2, SSI_FRF_MOTO_MODE_3, SSI_FRF_TI, or SSI_FRF_NMW. The

Motorola frame formats imply the following polarity and phase configurations:

Polarity Phase Mode

164 October 11, 2007


0

0

1

1

0 SSI_FRF_MOTO_MODE_0




The parameter ulMode defines the operating mode of the SSI module. The SSI module can operate as a master or slave; if a slave, the SSI can be configured to disable output on its serial output line. The parameter ulMode can be one of the following values: SSI_MODE_MASTER,

SSI_MODE_SLAVE, or SSI_MODE_SLAVE_OD.

The parameter ulBitRate defines the bit rate for the SSI. This bit rate must satisfy the following clock ratio criteria:

FSSI >= 2 ∗ bit rate (master mode)

FSSI >= 12 ∗ bit rate (slave modes) where FSSI is the frequency of the clock supplied to the SSI module.

The parameter ulDataWidth defines the width of the data transfers. The parameter ulDataWidth can be a value between 4 and 16, inclusive.




SysCtlClockGet() ).

This function replaces the original SSIConfig() API and performs the same actions. A macro is provided in ssi.h to map the original API to this API.

Returns:

None.

13.2.2.2 SSIDataGet

Gets a data element from the SSI receive FIFO.

Prototype:

void

SSIDataGet(unsigned long ulBase, unsigned long *pulData)

Parameters:


pulData pointer to a storage location for data that was received over the SSI interface.

Description:

This function will get received data from the receive FIFO of the specified SSI module, and place that data into the location specified by the pulData parameter.

Note:

Only the lower N bits of the value written to pulData will contain valid data, where N is the data width as configured by SSIConfig(). For example, if the interface is configured for 8 bit data width, only the lower 8 bits of the value written to pulData will contain valid data.

Returns:

None.

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13.2.2.3 SSIDataGetNonBlocking

Gets a data element from the SSI receive FIFO.

Prototype:

long

SSIDataGetNonBlocking(unsigned long ulBase, unsigned long *pulData)

Parameters:


pulData pointer to a storage location for data that was received over the SSI interface.

Description:

This function will get received data from the receive FIFO of the specified SSI module, and place that data into the location specified by the ulData parameter. If there is no data in the

FIFO, then this function will return a zero.

This function replaces the original SSIDataNonBlockingGet() API and performs the same actions. A macro is provided in ssi.h to map the original API to this API.

Note:

Only the lower N bits of the value written to pulData will contain valid data, where N is the data width as configured by SSIConfig(). For example, if the interface is configured for 8 bit data width, only the lower 8 bits of the value written to pulData will contain valid data.

Returns:

Returns the number of elements read from the SSI receive FIFO.

13.2.2.4 SSIDataPut

Puts a data element into the SSI transmit FIFO.

Prototype:

void

SSIDataPut(unsigned long ulBase, unsigned long ulData)

Parameters:


ulData data to be transmitted over the SSI interface.

Description:

This function will place the supplied data into the transmit FIFO of the specified SSI module.

Note:

The upper 32 - N bits of the ulData will be discarded by the hardware, where N is the data width as configured by SSIConfig(). For example, if the interface is configured for 8 bit data width, the upper 24 bits of ulData will be discarded.

Returns:

None.

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13.2.2.5 SSIDataPutNonBlocking

Puts a data element into the SSI transmit FIFO.

Prototype:

long

SSIDataPutNonBlocking(unsigned long ulBase, unsigned long ulData)

Parameters:


ulData data to be transmitted over the SSI interface.

Description:

This function will place the supplied data into the transmit FIFO of the specified SSI module. If there is no space in the FIFO, then this function will return a zero.

This function replaces the original SSIDataNonBlockingPut() API and performs the same actions. A macro is provided in ssi.h to map the original API to this API.

Note:

The upper 32 - N bits of the ulData will be discarded by the hardware, where N is the data width as configured by SSIConfig(). For example, if the interface is configured for 8 bit data width, the upper 24 bits of ulData will be discarded.

Returns:

Returns the number of elements written to the SSI transmit FIFO.

13.2.2.6 SSIDisable

Disables the synchronous serial interface.

Prototype:

void

SSIDisable(unsigned long ulBase)

Parameters:


Description:

This will disable operation of the synchronous serial interface.

Returns:

None.

13.2.2.7 SSIEnable

Enables the synchronous serial interface.

Prototype:

void

SSIEnable(unsigned long ulBase)

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Parameters:


Description:

This will enable operation of the synchronous serial interface. It must be configured before it is enabled.

Returns:

None.

13.2.2.8 SSIIntClear

Clears SSI interrupt sources.

Prototype:

void

SSIIntClear(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

The specified SSI interrupt sources are cleared, so that they no longer assert. This must be done in the interrupt handler to keep it from being called again immediately upon exit. The parameter ulIntFlags can consist of either or both the SSI_RXTO and SSI_RXOR values.

Returns:

None.

13.2.2.9 SSIIntDisable

Disables individual SSI interrupt sources.

Prototype:

void

SSIIntDisable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:


ulIntFlags is a bit mask of the interrupt sources to be disabled.

Description:

Disables the indicated SSI interrupt sources. The parameter ulIntFlags Can be any of the

SSI_TXFF, SSI_RXFF, SSI_RXTO, or SSI_RXOR values.

Returns:

None.

168 October 11, 2007


13.2.2.10 SSIIntEnable

Enables individual SSI interrupt sources.

Prototype:

void

SSIIntEnable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:


ulIntFlags is a bit mask of the interrupt sources to be enabled.

Description:

Enables the indicated SSI interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor. The parameter ulIntFlags Can be any of the SSI_TXFF, SSI_RXFF, SSI_RXTO, or SSI_RXOR values.

Returns:

None.

13.2.2.11 SSIIntRegister

Registers an interrupt handler for the synchronous serial interface.

Prototype:

void

SSIIntRegister(unsigned long ulBase, void (*pfnHandler)(void))

Parameters:


pfnHandler is a pointer to the function to be called when the synchronous serial interface interrupt occurs.

Description:

This sets the handler to be called when an SSI interrupt occurs. This will enable the global interrupt in the interrupt controller; specific SSI interrupts must be enabled via

SSIIntEnable() .

If necessary, it is the interrupt handler’s responsibility to clear the interrupt source via

SSIInt-

Clear() .

See also:

IntRegister()


Returns:

None.

13.2.2.12 SSIIntStatus


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Prototype:

unsigned long

SSIIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:



Description:

This returns the interrupt status for the SSI module. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:

The current interrupt status, enumerated as a bit field of SSI_TXFF, SSI_RXFF, SSI_RXTO, and SSI_RXOR.

13.2.2.13 SSIIntUnregister

Unregisters an interrupt handler for the synchronous serial interface.

Prototype:

void

SSIIntUnregister(unsigned long ulBase)

Parameters:


Description:

This function will clear the handler to be called when a SSI interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

See also:

IntRegister()


Returns:

None.

13.3


The following example shows how to use the SSI API to configure the SSI module as a master device, and how to do a simple send of data.

char *pcChars = "SSI Master send data."; long lIdx;

//

// Configure the SSI.

//

SSIConfigSetExpClk(SSI_BASE, SysCtlClockGet(), SSI_FRF_MOTO_MODE0,

170 October 11, 2007

SSI_MODE_MASTER, 2000000, 8);

//

// Enable the SSI module.

//

SSIEnable(SSI_BASE);

//

// Send some data.

// lIdx = 0; while(pcChars[lIdx])

{ if(SSIDataPut(SSI_BASE, pcChars[lIdx]))

{ lIdx++;

}

}


October 11, 2007 171


172 October 11, 2007


14 System Control

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172


14.1

Introduction

System control determines the overall operation of the device. It controls the clocking of the device, the set of peripherals that are enabled, configuration of the device and its resets, and provides information about the device.

The members of the Stellaris family have a varying peripheral set and memory sizes. The device has a set of read-only registers that indicate the size of the memories, the peripherals that are present, and the pins that are present for peripherals that have a varying number of pins. This information can be used to write adaptive software that will run on more than one member of the

Stellaris family.

The device can be clocked from one of five sources: an external oscillator, the main oscillator, the internal oscillator, the internal oscillator divided by four, or the PLL. The PLL can use any of the four oscillators as its input. Since the internal oscillator has a very wide error range (+/- 50%), it cannot be used for applications that require specific timing; its real use is for detecting failures of the main oscillator and the PLL, and for applications that strictly respond to external events and do not use time-based peripherals (such as a UART). When using the PLL, the input clock frequency is constrained to specific frequencies between 3.579545 MHz and 8.192 MHz (i.e. the standard crystal frequencies in that range). When direct clocking with an external oscillator or the main oscillator, the frequency is constrained to between 0 Hz and 50 MHz (depending on the part).

The internal oscillator is 15 MHz, +/- 50%; its frequency will vary by device, with voltage, and with temperature. The internal oscillator provides no tuning or frequency measurement mechanism; its frequency is not adjustable.

Almost the entire device operates from a single clock. The ADC and PWM blocks have their own clocks. In order to use the ADC, the PLL must be used; the PLL output will be used to create the clock required by the ADC. The PWM has its own optional divider from the system clock; this can be power of two divides between 1 and 64.

Three modes of operation are supported by the Stellaris family: run mode, sleep mode, and deepsleep mode. In run mode, the processor is actively executing code. In sleep mode, the clocking of the device is unchanged but the processor no longer executes code (and is no longer clocked).

In deep-sleep mode, the clocking of the device may change (depending upon the run mode clock configuration) and the processor no longer executes code (and is no longer clocked). An interrupt will return the device to run mode from one of the sleep modes; the sleep modes are entered upon request from the code.

The device has an internal LDO for generating the on-chip 2.5 V power supply; the output voltage of the LDO can be adjusted between 2.25 V and 2.75 V. Depending upon the application, lower voltage may be advantageous for its power savings, or higher voltage may be advantageous for its improved performance. The default setting of 2.5 V is a good compromise between the two, and should not be changed without careful consideration and evaluation.

There are several system events that, when detected, will cause system control to reset the device.

These events are the input voltage dropping too low, the LDO voltage dropping too low, an external

October 11, 2007 173

System Control reset, a software reset request, and a watchdog timeout. The properties of some of these events can be configured, and the reason for a reset can be determined from system control.

Each peripheral in the device can be individually enabled, disabled, or reset. Additionally, the set of peripherals that remain enabled during sleep mode and deep-sleep mode can be configured, allowing custom sleep and deep-sleep modes to be defined. Care must be taken with deep-sleep mode, though, since in this mode the PLL is no longer used and the system is clocked by the input crystal. Peripherals that depend upon a particular input clock rate (such as a UART) will not operate as expected in deep-sleep mode due to the clock rate change; these peripherals must either be reconfigured upon entry to and exit from deep-sleep mode, or simply not enabled in deep-sleep mode.

There are various system events that, when detected, will cause system control to generate a processor interrupt. These events are the PLL achieving lock, the internal LDO current limit being exceeded, the internal oscillator failing, the main oscillator failing, the input voltage dropping too low, the internal LDO voltage dropping too low, and the PLL failing. Each of these interrupts can be individually enabled or disabled, and the sources must be cleared by the interrupt handler when they occur.

14.2

API Functions


SysCtlADCSpeedGet

(void) void

SysCtlADCSpeedSet

(unsigned long ulSpeed) void

SysCtlBrownOutConfigSet

(unsigned long ulConfig, unsigned long ulDelay) void

SysCtlClkVerificationClear


SysCtlClockGet

(void) void

SysCtlClockSet

(unsigned long ulConfig) void

SysCtlDeepSleep


SysCtlFlashSizeGet

(void) void

SysCtlIntClear

(unsigned long ulInts) void

SysCtlIntDisable


SysCtlIntEnable


SysCtlIntRegister

(void (∗pfnHandler)(void)) unsigned long

SysCtlIntStatus


SysCtlIntUnregister

(void) void

SysCtlIOSCVerificationSet

(tBoolean bEnable) void

SysCtlLDOConfigSet

(unsigned long ulConfig) unsigned long

SysCtlLDOGet

(void) void

SysCtlLDOSet

(unsigned long ulVoltage) void

SysCtlMOSCVerificationSet


SysCtlPeripheralClockGating


SysCtlPeripheralDeepSleepDisable

(unsigned long ulPeripheral) void

SysCtlPeripheralDeepSleepEnable


SysCtlPeripheralDisable


SysCtlPeripheralEnable

(unsigned long ulPeripheral)

174 October 11, 2007

Stellaris Peripheral Driver Library User’s Guide tBoolean

SysCtlPeripheralPresent


SysCtlPeripheralReset


SysCtlPeripheralSleepDisable


SysCtlPeripheralSleepEnable

(unsigned long ulPeripheral) tBoolean

SysCtlPinPresent

(unsigned long ulPin) void

SysCtlPLLVerificationSet

(tBoolean bEnable) unsigned long

SysCtlPWMClockGet

(void) void

SysCtlPWMClockSet

(unsigned long ulConfig) void

SysCtlReset

(void) void

SysCtlResetCauseClear

(unsigned long ulCauses) unsigned long

SysCtlResetCauseGet

(void) void

SysCtlSleep


SysCtlSRAMSizeGet

(void)

14.2.1


The SysCtl API is broken up into eight groups of functions: those that provide device information, those that deal with device clocking, those that provide peripheral control, those that deal with the

SysCtl interrupt, those that deal with the LDO, those that deal with sleep modes, those that deal with reset reasons, those that deal with the brown-out reset, and those that deal with clock verification timers.

Information about the device is provided by

SysCtlSRAMSizeGet() ,

SysCtlFlashSizeGet() ,

SysCtl-

PeripheralPresent() , and

SysCtlPinPresent() .

Clocking of the device is configured with

SysCtlClockSet()

and

SysCtlPWMClockSet() . Information

about device clocking is provided by

SysCtlClockGet()

and

SysCtlPWMClockGet() .

Peripheral enabling and reset are controlled with

SysCtlPeripheralReset() ,

SysCtlPeripheral-

Enable() , SysCtlPeripheralDisable() ,

SysCtlPeripheralSleepEnable() ,

SysCtlPeripheralSleep-

Disable() ,

SysCtlPeripheralDeepSleepEnable() ,

SysCtlPeripheralDeepSleepDisable() , and SysCtl-

PeripheralClockGating() .

The system control interrupt is managed with

SysCtlIntRegister() ,

SysCtlIntUnregister() ,

SysCtlInt-

Enable() ,

SysCtlIntDisable() , SysCtlIntClear() ,

SysCtlIntStatus() .

The LDO is controlled with

SysCtlLDOSet()

and

SysCtlLDOConfigSet() . Its status is provided by

SysCtlLDOGet() .

The device is put into sleep modes with

SysCtlSleep()

and

SysCtlDeepSleep() .

The reset reason is managed with

SysCtlResetCauseGet()

and

SysCtlResetCauseClear() . A soft-

ware reset is performed with

SysCtlReset() .

The brown-out reset is configured with

SysCtlBrownOutConfigSet() .

The clock verification timers are managed with

SysCtlIOSCVerificationSet() ,

SysCtl-

MOSCVerificationSet() ,

SysCtlPLLVerificationSet() , and

SysCtlClkVerificationClear() .

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System Control

14.2.2


14.2.2.1 SysCtlADCSpeedGet

Gets the sample rate of the ADC.

Prototype:

unsigned long

SysCtlADCSpeedGet(void)

Description:

This function gets the current sample rate of the ADC.

Returns:

Returns the current ADC sample rate; will be one of

SYSCTL_ADCSPEED_-

1MSPS, SYSCTL_ADCSPEED_500KSPS, SYSCTL_ADCSPEED_250KSPS, or SYSCTL_-

ADCSPEED_125KSPS.

14.2.2.2 SysCtlADCSpeedSet

Sets the sample rate of the ADC.

Prototype:

void

SysCtlADCSpeedSet(unsigned long ulSpeed)

Parameters:

ulSpeed is the desired sample rate of the ADC; must be one of SYSCTL_ADCSPEED_-

1MSPS, SYSCTL_ADCSPEED_500KSPS, SYSCTL_ADCSPEED_250KSPS, or

SYSCTL_ADCSPEED_125KSPS.

Description:

This function sets the rate at which the ADC samples are captured by the ADC block. The sampling speed may be limited by the hardware, so the sample rate may end up being slower than requested.

SysCtlADCSpeedGet()

will return the actual speed in use.

Returns:

None.

14.2.2.3 SysCtlBrownOutConfigSet

Configures the brown-out control.

Prototype:

void

SysCtlBrownOutConfigSet(unsigned long ulConfig, unsigned long ulDelay)

Parameters:

ulConfig is the desired configuration of the brown-out control. Must be the logical OR of

SYSCTL_BOR_RESET and/or SYSCTL_BOR_RESAMPLE.

176 October 11, 2007


ulDelay is the number of internal oscillator cycles to wait before resampling an asserted brown-out signal. This value only has meaning when SYSCTL_BOR_RESAMPLE is set and must be less than 8192.

Description:

This function configures how the brown-out control operates. It can detect a brown-out by looking at only the brown-out output, or it can wait for it to be active for two consecutive samples separated by a configurable time. When it detects a brown-out condition, it can either reset the device or generate a processor interrupt.

Returns:

None.

14.2.2.4 SysCtlClkVerificationClear

Clears the clock verification status.

Prototype:

void

SysCtlClkVerificationClear(void)

Description:

This function clears the status of the clock verification timers, allowing them to assert another failure if detected.

The clock verification timers are only available on Sandstorm-class devices.

Returns:

None.

14.2.2.5 SysCtlClockGet

Gets the processor clock rate.

Prototype:

unsigned long

SysCtlClockGet(void)

Description:

This function determines the clock rate of the processor clock. This is also the clock rate of all the peripheral modules (with the exception of PWM, which has its own clock divider).

Note:

This will not return accurate results if

SysCtlClockSet()

has not been called to configure the clocking of the device, or if the device is directly clocked from a crystal (or a clock source) that is not one of the supported crystal frequencies. In the later case, this function should be modified to directly return the correct system clock rate.

Returns:

The processor clock rate.

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System Control

14.2.2.6 SysCtlClockSet

Sets the clocking of the device.

Prototype:

void

SysCtlClockSet(unsigned long ulConfig)

Parameters:

ulConfig is the required configuration of the device clocking.

Description:

This function configures the clocking of the device. The input crystal frequency, oscillator to be used, use of the PLL, and the system clock divider are all configured with this function.

The ulConfig parameter is the logical OR of several different values, many of which are grouped into sets where only one can be chosen.

The system clock divider is chosen with one of the following values:

SYSCTL_SYSDIV_-

1, SYSCTL_SYSDIV_2, SYSCTL_SYSDIV_3, SYSCTL_SYSDIV_4, SYSCTL_SYSDIV_-

5, SYSCTL_SYSDIV_6, SYSCTL_SYSDIV_7, SYSCTL_SYSDIV_8, SYSCTL_SYSDIV_9,

SYSCTL_SYSDIV_10, SYSCTL_SYSDIV_11, SYSCTL_SYSDIV_12, SYSCTL_SYSDIV_13,

SYSCTL_SYSDIV_14, SYSCTL_SYSDIV_15, or SYSCTL_SYSDIV_16.

The use of the PLL is chosen with either

SYSCTL_USE_PLL or SYSCTL_USE_OSC.

The external crystal frequency is chosen with one of the following values:

SYSCTL_XTAL_-

1MHZ, SYSCTL_XTAL_1_84MHZ, SYSCTL_XTAL_2MHZ, SYSCTL_XTAL_2_45MHZ,

SYSCTL_XTAL_3_57MHZ, SYSCTL_XTAL_3_68MHZ, SYSCTL_XTAL_4MHZ, SYSCTL_-

XTAL_4_09MHZ, SYSCTL_XTAL_4_91MHZ, SYSCTL_XTAL_5MHZ, SYSCTL_XTAL_5_-

12MHZ, SYSCTL_XTAL_6MHZ, SYSCTL_XTAL_6_14MHZ, SYSCTL_XTAL_7_37MHZ,

SYSCTL_XTAL_8MHZ, or SYSCTL_XTAL_8_19MHZ. Values below SYSCTL_XTAL_3_-

57MHZ are not valid when the PLL is in operation.

The oscillator source is chosen with one of the following values: SYSCTL_OSC_MAIN,

SYSCTL_OSC_INT, or SYSCTL_OSC_INT4.

The internal and main oscillators are disabled with the SYSCTL_INT_OSC_DIS and

SYSCTL_MAIN_OSC_DIS flags, respectively. The external oscillator must be enabled in order to use an external clock source. Note that attempts to disable the oscillator used to clock the device will be prevented by the hardware.

To clock the system from an external source (such as an external crystal oscillator), use

SYSCTL_USE_OSC | SYSCTL_OSC_MAIN. To clock the system from the main oscillator, use SYSCTL_USE_OSC | SYSCTL_OSC_MAIN. To clock the system from the PLL, use

SYSCTL_USE_PLL | SYSCTL_OSC_MAIN, and select the appropriate crystal with one of the SYSCTL_XTAL_xxx values.

Note:

If selecting the PLL as the system clock source (i.e. via SYSCTL_USE_PLL), this function will poll the PLL lock interrupt to determine when the PLL has locked. If an interrupt handler for the system control interrupt is in place, and it responds to and clears the PLL lock interrupt, this function will delay until its timeout has occurred instead of completing as soon as PLL lock is achieved.

Returns:

None.

178 October 11, 2007


14.2.2.7 SysCtlDeepSleep

Puts the processor into deep-sleep mode.

Prototype:

void

SysCtlDeepSleep(void)

Description:

This function places the processor into deep-sleep mode; it will not return until the processor returns to run mode. The peripherals that are enabled via

SysCtlPeripheralDeepSleepEnable()

continue to operate and can wake up the processor (if automatic clock gating is enabled with

SysCtlPeripheralClockGating() , otherwise all peripherals continue to operate).

Returns:

None.

14.2.2.8 SysCtlFlashSizeGet

Gets the size of the flash.

Prototype:

unsigned long

SysCtlFlashSizeGet(void)

Description:

This function determines the size of the flash on the Stellaris device.

Returns:

The total number of bytes of flash.

14.2.2.9 SysCtlIntClear

Clears system control interrupt sources.

Prototype:

void

SysCtlIntClear(unsigned long ulInts)

Parameters:

ulInts is a bit mask of the interrupt sources to be cleared.

Must be a logical OR of SYSCTL_INT_PLL_LOCK, SYSCTL_INT_CUR_LIMIT, SYSCTL_INT_IOSC_FAIL,

SYSCTL_INT_MOSC_FAIL, SYSCTL_INT_POR, SYSCTL_INT_BOR, and/or SYSCTL_-

INT_PLL_FAIL.

Description:

The specified system control interrupt sources are cleared, so that they no longer assert. This must be done in the interrupt handler to keep it from being called again immediately upon exit.

Returns:

None.

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System Control

14.2.2.10 SysCtlIntDisable

Disables individual system control interrupt sources.

Prototype:

void

SysCtlIntDisable(unsigned long ulInts)

Parameters:

ulInts is a bit mask of the interrupt sources to be disabled.



INT_PLL_FAIL.

Description:

Disables the indicated system control interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.

Returns:

None.

14.2.2.11 SysCtlIntEnable

Enables individual system control interrupt sources.

Prototype:

void

SysCtlIntEnable(unsigned long ulInts)

Parameters:

ulInts is a bit mask of the interrupt sources to be enabled.



INT_PLL_FAIL.

Description:

Enables the indicated system control interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.

Returns:

None.

14.2.2.12 SysCtlIntRegister

Registers an interrupt handler for the system control interrupt.

Prototype:

void

SysCtlIntRegister(void (*pfnHandler)(void))

180 October 11, 2007


Parameters:

pfnHandler is a pointer to the function to be called when the system control interrupt occurs.

Description:

This sets the handler to be called when a system control interrupt occurs. This will enable the global interrupt in the interrupt controller; specific system control interrupts must be enabled via

SysCtlIntEnable() . It is the interrupt handler’s responsibility to clear the interrupt source via

SysCtlIntClear() .

System control can generate interrupts when the PLL achieves lock, if the internal LDO current limit is exceeded, if the internal oscillator fails, if the main oscillator fails, if the internal LDO output voltage droops too much, if the external voltage droops too much, or if the PLL fails.

See also:

IntRegister()


Returns:

None.

14.2.2.13 SysCtlIntStatus


Prototype:

unsigned long

SysCtlIntStatus(tBoolean bMasked)

Parameters:


Description:

This returns the interrupt status for the system controller. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:

The current interrupt status, enumerated as a bit field of

SYSCTL_INT_PLL_-

LOCK, SYSCTL_INT_CUR_LIMIT, SYSCTL_INT_IOSC_FAIL, SYSCTL_INT_MOSC_FAIL,

SYSCTL_INT_POR, SYSCTL_INT_BOR, and SYSCTL_INT_PLL_FAIL.

14.2.2.14 SysCtlIntUnregister

Unregisters the interrupt handler for the system control interrupt.

Prototype:

void

SysCtlIntUnregister(void)

Description:

This function will clear the handler to be called when a system control interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

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System Control

See also:

IntRegister()


Returns:

None.

14.2.2.15 SysCtlIOSCVerificationSet

Configures the internal oscillator verification timer.

Prototype:

void

SysCtlIOSCVerificationSet(tBoolean bEnable)

Parameters:

bEnable is a boolean that is true if the internal oscillator verification timer should be enabled.

Description:

This function allows the internal oscillator verification timer to be enabled or disabled. When enabled, an interrupt will be generated if the internal oscillator ceases to operate.

The internal osscillator verification timer is only available on Sandstorm-class devices.

Note:

Both oscillators (main and internal) must be enabled for this verification timer to operate as the main oscillator will verify the internal oscillator.

Returns:

None.

14.2.2.16 SysCtlLDOConfigSet

Configures the LDO failure control.

Prototype:

void

SysCtlLDOConfigSet(unsigned long ulConfig)

Parameters:

ulConfig is the required LDO failure control setting; can be either SYSCTL_LDOCFG_ARST or SYSCTL_LDOCFG_NORST.

Description:

This function allows the LDO to be configured to cause a processor reset when the output voltage becomes unregulated.

The LDO failure control is only available on Sandstorm-class devices.

Returns:

None.

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14.2.2.17 SysCtlLDOGet

Gets the output voltage of the LDO.

Prototype:

unsigned long

SysCtlLDOGet(void)

Description:

This function determines the output voltage of the LDO, as specified by the control register.

Returns:

Returns the current voltage of the LDO; will be one of SYSCTL_LDO_2_25V,

SYSCTL_LDO_2_30V, SYSCTL_LDO_2_35V, SYSCTL_LDO_2_40V, SYSCTL_LDO_2_-

45V, SYSCTL_LDO_2_50V, SYSCTL_LDO_2_55V, SYSCTL_LDO_2_60V, SYSCTL_-

LDO_2_65V, SYSCTL_LDO_2_70V, or SYSCTL_LDO_2_75V.

14.2.2.18 SysCtlLDOSet

Sets the output voltage of the LDO.

Prototype:

void

SysCtlLDOSet(unsigned long ulVoltage)

Parameters:

ulVoltage is the required output voltage from the LDO. Must be one of SYSCTL_LDO_2_-

25V, SYSCTL_LDO_2_30V, SYSCTL_LDO_2_35V, SYSCTL_LDO_2_40V, SYSCTL_-

LDO_2_45V, SYSCTL_LDO_2_50V, SYSCTL_LDO_2_55V, SYSCTL_LDO_2_60V,

SYSCTL_LDO_2_65V, SYSCTL_LDO_2_70V, or SYSCTL_LDO_2_75V.

Description:

This function sets the output voltage of the LDO. The default voltage is 2.5 V; it can be adjusted

+/- 10%.

Returns:

None.

14.2.2.19 SysCtlMOSCVerificationSet

Configures the main oscillator verification timer.

Prototype:

void

SysCtlMOSCVerificationSet(tBoolean bEnable)

Parameters:

bEnable is a boolean that is true if the main oscillator verification timer should be enabled.

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Description:

This function allows the main oscillator verification timer to be enabled or disabled. When enabled, an interrupt will be generated if the main oscillator ceases to operate.

The main osscillator verification timer is only available on Sandstorm-class devices.

Note:

Both oscillators (main and internal) must be enabled for this verification timer to operate as the internal oscillator will verify the main oscillator.

Returns:

None.

14.2.2.20 SysCtlPeripheralClockGating

Controls peripheral clock gating in sleep and deep-sleep mode.

Prototype:

void

SysCtlPeripheralClockGating(tBoolean bEnable)

Parameters:

bEnable is a boolean that is true if the sleep and deep-sleep peripheral configuration should be used and false if not.

Description:

This function controls how peripherals are clocked when the processor goes into sleep or deepsleep mode. By default, the peripherals are clocked the same as in run mode; if peripheral clock gating is enabled they are clocked according to the configuration set by

SysCtlPeripheralSleep-

Enable() ,

SysCtlPeripheralSleepDisable() ,

SysCtlPeripheralDeepSleepEnable() , and

SysCtl-

PeripheralDeepSleepDisable() .

Returns:

None.

14.2.2.21 SysCtlPeripheralDeepSleepDisable

Disables a peripheral in deep-sleep mode.

Prototype:

void

SysCtlPeripheralDeepSleepDisable(unsigned long ulPeripheral)

Parameters:

ulPeripheral is the peripheral to disable in deep-sleep mode.

Description:

This function causes a peripheral to stop operating when the processor goes into deep-sleep mode. Disabling peripherals while in deep-sleep mode helps to lower the current draw of the device, and can keep peripherals that require a particular clock frequency from operating when

184 October 11, 2007

Stellaris Peripheral Driver Library User’s Guide the clock changes as a result of entering deep-sleep mode. If enabled (via

SysCtlPeripheral-

Enable() ), the peripheral will automatically resume operation when the processor leaves deep-

sleep mode, maintaining its entire state from before deep-sleep mode was entered.

Deep-sleep mode clocking of peripherals must be enabled via

SysCtlPeripheralClockGating() ;

if disabled, the peripheral deep-sleep mode configuration is maintained but has no effect when deep-sleep mode is entered.

The ulPeripheral argument must be one of the following values: SYSCTL_PERIPH_ADC,

SYSCTL_PERIPH_CAN0, SYSCTL_PERIPH_CAN1, SYSCTL_PERIPH_CAN2, SYSCTL_-

PERIPH_COMP0, SYSCTL_PERIPH_COMP1, SYSCTL_PERIPH_COMP2,

SYSCTL_-

PERIPH_ETH, SYSCTL_PERIPH_GPIOA, SYSCTL_PERIPH_GPIOB, SYSCTL_PERIPH_-

GPIOC, SYSCTL_PERIPH_GPIOD, SYSCTL_PERIPH_GPIOE, SYSCTL_PERIPH_GPIOF,

SYSCTL_PERIPH_GPIOG, SYSCTL_PERIPH_GPIOH, SYSCTL_PERIPH_HIBERNATE,

SYSCTL_PERIPH_I2C0, SYSCTL_PERIPH_I2C1, SYSCTL_PERIPH_PWM, SYSCTL_-

PERIPH_QEI0, SYSCTL_PERIPH_QEI1, SYSCTL_PERIPH_SSI0, SYSCTL_PERIPH_SSI1,

SYSCTL_PERIPH_TIMER0, SYSCTL_PERIPH_TIMER1, SYSCTL_PERIPH_TIMER2,

SYSCTL_PERIPH_TIMER3, SYSCTL_PERIPH_UART0, SYSCTL_PERIPH_UART1,

SYSCTL_PERIPH_UART2, or SYSCTL_PERIPH_WDOG.

Returns:

None.

14.2.2.22 SysCtlPeripheralDeepSleepEnable

Enables a peripheral in deep-sleep mode.

Prototype:

void

SysCtlPeripheralDeepSleepEnable(unsigned long ulPeripheral)

Parameters:

ulPeripheral is the peripheral to enable in deep-sleep mode.

Description:

This function allows a peripheral to continue operating when the processor goes into deepsleep mode. Since the clocking configuration of the device may change, not all peripherals can safely continue operating while the processor is in sleep mode. Those that must run at a particular frequency (such as a UART) will not work as expected if the clock changes. It is the responsibility of the caller to make sensible choices.

Deep-sleep mode clocking of peripherals must be enabled via

SysCtlPeripheralClockGating() ;

if disabled, the peripheral deep-sleep mode configuration is maintained but has no effect when deep-sleep mode is entered.

The ulPeripheral argument must be one of the following values: SYSCTL_PERIPH_ADC,



SYSCTL_-







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SYSCTL_PERIPH_TIMER3, SYSCTL_PERIPH_UART0,


Returns:

None.

SYSCTL_PERIPH_UART1,

14.2.2.23 SysCtlPeripheralDisable

Disables a peripheral.

Prototype:

void

SysCtlPeripheralDisable(unsigned long ulPeripheral)

Parameters:

ulPeripheral is the peripheral to disable.

Description:

Peripherals are disabled with this function. Once disabled, they will not operate or respond to register reads/writes.

The ulPeripheral argument must be only one of the following values: SYSCTL_PERIPH_ADC,



SYSCTL_-










Returns:

None.

14.2.2.24 SysCtlPeripheralEnable

Enables a peripheral.

Prototype:

void

SysCtlPeripheralEnable(unsigned long ulPeripheral)

Parameters:

ulPeripheral is the peripheral to enable.

Description:

Peripherals are enabled with this function. At power-up, all peripherals are disabled; they must be enabled in order to operate or respond to register reads/writes.

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SYSCTL_-










Returns:

None.

14.2.2.25 SysCtlPeripheralPresent

Determines if a peripheral is present.

Prototype:

tBoolean

SysCtlPeripheralPresent(unsigned long ulPeripheral)

Parameters:

ulPeripheral is the peripheral in question.

Description:

Determines if a particular peripheral is present in the device. Each member of the Stellaris family has a different peripheral set; this will determine which are present on this device.




SYSCTL_-




SYSCTL_PERIPH_I2C0, SYSCTL_PERIPH_I2C1, SYSCTL_PERIPH_MPU, SYSCTL_-

PERIPH_PLL, SYSCTL_PERIPH_PWM, SYSCTL_PERIPH_QEI0, SYSCTL_PERIPH_QEI1,

SYSCTL_PERIPH_SSI0, SYSCTL_PERIPH_SSI1, SYSCTL_PERIPH_TEMP, SYSCTL_-

PERIPH_TIMER0, SYSCTL_PERIPH_TIMER1, SYSCTL_PERIPH_TIMER2,

SYSCTL_-

PERIPH_TIMER3, SYSCTL_PERIPH_UART0, SYSCTL_PERIPH_UART1,

SYSCTL_-

PERIPH_UART2, or SYSCTL_PERIPH_WDOG.

Returns:

Returns

true if the specified peripheral is present and false if it is not.

14.2.2.26 SysCtlPeripheralReset

Performs a software reset of a peripheral.

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Prototype:

void

SysCtlPeripheralReset(unsigned long ulPeripheral)

Parameters:

ulPeripheral is the peripheral to reset.

Description:

This function performs a software reset of the specified peripheral. An individual peripheral reset signal is asserted for a brief period and then deasserted, leaving the peripheral in a operating state but in its reset condition.




SYSCTL_-







SYSCTL_PERIPH_TIMER3, SYSCTL_PERIPH_UART0, SYSCTL_PERIPH_UART1,


Returns:

None.

14.2.2.27 SysCtlPeripheralSleepDisable

Disables a peripheral in sleep mode.

Prototype:

void

SysCtlPeripheralSleepDisable(unsigned long ulPeripheral)

Parameters:

ulPeripheral is the peripheral to disable in sleep mode.

Description:

This function causes a peripheral to stop operating when the processor goes into sleep mode.

Disabling peripherals while in sleep mode helps to lower the current draw of the device. If enabled (via

SysCtlPeripheralEnable() ), the peripheral will automatically resume operation when

the processor leaves sleep mode, maintaining its entire state from before sleep mode was entered.

Sleep mode clocking of peripherals must be enabled via

SysCtlPeripheralClockGating() ; if dis-

abled, the peripheral sleep mode configuration is maintained but has no effect when sleep mode is entered.

The

ulPeripheral argument must be only one of the following values: SYSCTL_PERIPH_ADC,



SYSCTL_-



188 October 11, 2007









Returns:

None.

14.2.2.28 SysCtlPeripheralSleepEnable

Enables a peripheral in sleep mode.

Prototype:

void

SysCtlPeripheralSleepEnable(unsigned long ulPeripheral)

Parameters:

ulPeripheral is the peripheral to enable in sleep mode.

Description:

This function allows a peripheral to continue operating when the processor goes into sleep mode. Since the clocking configuration of the device does not change, any peripheral can safely continue operating while the processor is in sleep mode, and can therefore wake the processor from sleep mode.

Sleep mode clocking of peripherals must be enabled via

SysCtlPeripheralClockGating() ; if dis-

abled, the peripheral sleep mode configuration is maintained but has no effect when sleep mode is entered.




SYSCTL_-










Returns:

None.

14.2.2.29 SysCtlPinPresent

Determines if a pin is present.

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System Control

Prototype:

tBoolean

SysCtlPinPresent(unsigned long ulPin)

Parameters:

ulPin is the pin in question.

Description:

Determines if a particular pin is present in the device. The PWM, analog comparators, ADC, and timers have a varying number of pins across members of the Stellaris family; this will determine which are present on this device.

The ulPin argument must be only one of the following values: SYSCTL_PIN_PWM0,

SYSCTL_PIN_PWM1, SYSCTL_PIN_PWM2, SYSCTL_PIN_PWM3, SYSCTL_PIN_PWM4,

SYSCTL_PIN_PWM5, SYSCTL_PIN_C0MINUS, SYSCTL_PIN_C0PLUS, SYSCTL_PIN_-

C0O, SYSCTL_PIN_C1MINUS, SYSCTL_PIN_C1PLUS, SYSCTL_PIN_C1O, SYSCTL_-

PIN_C2MINUS, SYSCTL_PIN_C2PLUS, SYSCTL_PIN_C2O, SYSCTL_PIN_ADC0,

SYSCTL_PIN_ADC1, SYSCTL_PIN_ADC2, SYSCTL_PIN_ADC3, SYSCTL_PIN_ADC4,

SYSCTL_PIN_ADC5, SYSCTL_PIN_ADC6, SYSCTL_PIN_ADC7, SYSCTL_PIN_CCP0,

SYSCTL_PIN_CCP1, SYSCTL_PIN_CCP2, SYSCTL_PIN_CCP3, SYSCTL_PIN_CCP4,

SYSCTL_PIN_CCP5, SYSCTL_PIN_CCP6, SYSCTL_PIN_CCP7, SYSCTL_PIN_32KHZ, or

SYSCTL_PIN_MC_FAULT0.

Returns:

Returns true if the specified pin is present and false if it is not.

14.2.2.30 SysCtlPLLVerificationSet

Configures the PLL verification timer.

Prototype:

void

SysCtlPLLVerificationSet(tBoolean bEnable)

Parameters:

bEnable is a boolean that is true if the PLL verification timer should be enabled.

Description:

This function allows the PLL verification timer to be enabled or disabled. When enabled, an interrupt will be generated if the PLL ceases to operate.

The PLL verification timer is only available on Sandstorm-class devices.

Note:

The main oscillator must be enabled for this verification timer to operate as it is used to check the PLL. Also, the verification timer should be disabled while the PLL is being reconfigured via

SysCtlClockSet() .

Returns:

None.

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14.2.2.31 SysCtlPWMClockGet

Gets the current PWM clock configuration.

Prototype:

unsigned long

SysCtlPWMClockGet(void)

Description:

This function returns the current PWM clock configuration.

Returns:

The current PWM clock configuration; will be one of SYSCTL_PWMDIV_1, SYSCTL_-

PWMDIV_2, SYSCTL_PWMDIV_4, SYSCTL_PWMDIV_8,

SYSCTL_PWMDIV_32, or SYSCTL_PWMDIV_64.

SYSCTL_PWMDIV_16,

14.2.2.32 SysCtlPWMClockSet

Sets the PWM clock configuration.

Prototype:

void

SysCtlPWMClockSet(unsigned long ulConfig)

Parameters:

ulConfig is the configuration for the PWM clock; it must be one of SYSCTL_PWMDIV_-

1, SYSCTL_PWMDIV_2, SYSCTL_PWMDIV_4, SYSCTL_PWMDIV_8,

SYSCTL_-

PWMDIV_16, SYSCTL_PWMDIV_32, or SYSCTL_PWMDIV_64.

Description:

This function sets the rate of the clock provided to the PWM module as a ratio of the processor clock. This clock is used by the PWM module to generate PWM signals; its rate forms the basis for all PWM signals.

Note:

The clocking of the PWM is dependent upon the system clock rate as configured by

SysCtl-

ClockSet() .

Returns:

None.

14.2.2.33 SysCtlReset

Resets the device.

Prototype:

void

SysCtlReset(void)

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System Control

Description:

This function will perform a software reset of the entire device. The processor and all peripherals will be reset and all device registers will return to their default values (with the exception of the reset cause register, which will maintain its current value but have the software reset bit set as well).

Returns:

This function does not return.

14.2.2.34 SysCtlResetCauseClear

Clears reset reasons.

Prototype:

void

SysCtlResetCauseClear(unsigned long ulCauses)

Parameters:

ulCauses are the reset causes to be cleared; must be a logical OR of SYSCTL_CAUSE_LDO,

SYSCTL_CAUSE_SW, SYSCTL_CAUSE_WDOG, SYSCTL_CAUSE_BOR, SYSCTL_-

CAUSE_POR, and/or SYSCTL_CAUSE_EXT.

Description:

This function clears the specified sticky reset reasons. Once cleared, another reset for the same reason can be detected, and a reset for a different reason can be distinguished (instead of having two reset causes set). If the reset reason is used by an application, all reset causes should be cleared after they are retrieved with

SysCtlResetCauseGet() .

Returns:

None.

14.2.2.35 SysCtlResetCauseGet

Gets the reason for a reset.

Prototype:

unsigned long

SysCtlResetCauseGet(void)

Description:

This function will return the reason(s) for a reset. Since the reset reasons are sticky until either cleared by software or an external reset, multiple reset reasons may be returned if multiple resets have occurred.

The reset reason will be a logical OR of

SYSCTL_-

CAUSE_LDO, SYSCTL_CAUSE_SW, SYSCTL_CAUSE_WDOG, SYSCTL_CAUSE_BOR,

SYSCTL_CAUSE_POR, and/or SYSCTL_CAUSE_EXT.

Returns:

The reason(s) for a reset.

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14.2.2.36 SysCtlSleep

Puts the processor into sleep mode.

Prototype:

void

SysCtlSleep(void)

Description:

This function places the processor into sleep mode; it will not return until the processor returns to run mode. The peripherals that are enabled via

SysCtlPeripheralSleepEnable()

continue to operate and can wake up the processor (if automatic clock gating is enabled with

SysCtl-

PeripheralClockGating() , otherwise all peripherals continue to operate).

Returns:

None.

14.2.2.37 SysCtlSRAMSizeGet

Gets the size of the SRAM.

Prototype:

unsigned long

SysCtlSRAMSizeGet(void)

Description:

This function determines the size of the SRAM on the Stellaris device.

Returns:

The total number of bytes of SRAM.

14.3


The following example shows how to use the SysCtl API to configure the device for normal operation.

//

// Configure the device to run at 20 MHz from the PLL using a 4 MHz crystal

// as the input.

//

SysCtlClockSet(SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_XTAL_4MHZ |

SYSCTL_OSC_MAIN);

//

// Enable the GPIO blocks and the SSI.

//

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI);

//

// Enable the GPIO blocks and the SSI in sleep mode.

//

October 11, 2007 193

System Control

SysCtlPeripheralSleepEnable(SYSCTL_PERIPH_GPIOA);

SysCtlPeripheralSleepEnable(SYSCTL_PERIPH_GPIOB);

SysCtlPeripheralSleepEnable(SYSCTL_PERIPH_SSI);

//

// Enable peripheral clock gating.

//

SysCtlPeripheralClockGating(true);

194 October 11, 2007


15 SysTick

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193


15.1

Introduction

SysTick is a simple timer that is part of the NVIC controller in the Cortex-M3 microprocessor. Its intended purpose is to provide a periodic interrupt for a RTOS, but it can be used for other simple timing purposes.

The SysTick interrupt handler does not need to clear the SysTick interrupt source. This will be done automatically by NVIC when the SysTick interrupt handler is called.

15.2

API Functions

Functions void

SysTickDisable

(void) void

SysTickEnable

(void) void

SysTickIntDisable

(void) void

SysTickIntEnable

(void) void

SysTickIntRegister

(void (∗pfnHandler)(void)) void

SysTickIntUnregister


SysTickPeriodGet

(void) void

SysTickPeriodSet

(unsigned long ulPeriod) unsigned long

SysTickValueGet

(void)

15.2.1


The SysTick API is fairly simple, like SysTick itself. There are functions for configuring and en-

abling SysTick ( SysTickEnable() ,

SysTickDisable() ,

SysTickPeriodSet() , SysTickPeriodGet() , and

SysTickValueGet()

) and functions for dealing with an interrupt handler for SysTick ( SysTickInt-

Register() , SysTickIntUnregister() ,

SysTickIntEnable() , and SysTickIntDisable() ).

15.2.2


15.2.2.1 SysTickDisable

Disables the SysTick counter.

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SysTick

Prototype:

void

SysTickDisable(void)

Description:

This will stop the SysTick counter. If an interrupt handler has been registered, it will no longer be called until SysTick is restarted.

Returns:

None.

15.2.2.2 SysTickEnable

Enables the SysTick counter.

Prototype:

void

SysTickEnable(void)

Description:

This will start the SysTick counter. If an interrupt handler has been registered, it will be called when the SysTick counter rolls over.

Note:

Calling this function will cause the SysTick counter to (re)commence counting from its current value. The counter is not automatically reloaded with the period as specified in a previous call to

SysTickPeriodSet() . If an immediate reload is required, register NVIC_ST_CURRENT must

be written to force this. Any write to this register clears the SysTick counter to 0 and will cause a reload with the supplied period on the next clock.

Returns:

None.

15.2.2.3 SysTickIntDisable

Disables the SysTick interrupt.

Prototype:

void

SysTickIntDisable(void)

Description:

This function will disable the SysTick interrupt, preventing it from being reflected to the processor.

Returns:

None.

196 October 11, 2007


15.2.2.4 SysTickIntEnable

Enables the SysTick interrupt.

Prototype:

void

SysTickIntEnable(void)

Description:

This function will enable the SysTick interrupt, allowing it to be reflected to the processor.

Note:

The SysTick interrupt handler does not need to clear the SysTick interrupt source as this is done automatically by NVIC when the interrupt handler is called.

Returns:

None.

15.2.2.5 SysTickIntRegister

Registers an interrupt handler for the SysTick interrupt.

Prototype:

void

SysTickIntRegister(void (*pfnHandler)(void))

Parameters:

pfnHandler is a pointer to the function to be called when the SysTick interrupt occurs.

Description:

This sets the handler to be called when a SysTick interrupt occurs.

See also:

IntRegister()


Returns:

None.

15.2.2.6 SysTickIntUnregister

Unregisters the interrupt handler for the SysTick interrupt.

Prototype:

void

SysTickIntUnregister(void)

Description:

This function will clear the handler to be called when a SysTick interrupt occurs.

See also:

IntRegister()


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Returns:

None.

15.2.2.7 SysTickPeriodGet

Gets the period of the SysTick counter.

Prototype:

unsigned long

SysTickPeriodGet(void)

Description:

This function returns the rate at which the SysTick counter wraps; this equates to the number of processor clocks between interrupts.

Returns:

Returns the period of the SysTick counter.

15.2.2.8 SysTickPeriodSet

Sets the period of the SysTick counter.

Prototype:

void

SysTickPeriodSet(unsigned long ulPeriod)

Parameters:

ulPeriod is the number of clock ticks in each period of the SysTick counter; must be between

1 and 16,777,216, inclusive.

Description:

This function sets the rate at which the SysTick counter wraps; this equates to the number of processor clocks between interrupts.

Note:

Calling this function does not cause the SysTick counter to reload immediately. If an immediate reload is required, register NVIC_ST_CURRENT must be written. Any write to this register clears the SysTick counter to 0 and will cause a reload with the ulPeriod supplied here on the next clock after the SysTick is enabled.

Returns:

None.

15.2.2.9 SysTickValueGet

Gets the current value of the SysTick counter.

Prototype:

unsigned long

SysTickValueGet(void)

198 October 11, 2007


Description:

This function returns the current value of the SysTick counter; this will be a value between the period - 1 and zero, inclusive.

Returns:

Returns the current value of the SysTick counter.

15.3


The following example shows how to use the SysTick API to configure the SysTick counter and read its value.

unsigned long ulValue;

//

// Configure and enable the SysTick counter.

//

SysTickPeriodSet(1000);

SysTickEnable();

//


//

//

// Read the current SysTick value.

// ulValue = SysTickValueGet();

October 11, 2007 199

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200 October 11, 2007


16 Timer

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199


16.1

Introduction

The timer API provides a set of functions for dealing with the timer module. Functions are provided to configure and control the timer, along with functions to modify timer/counter values, and to manage interrupt handling for the timer.

The timer module provides two 16-bit timer/counters that can be configured to operate independently as timers or event counters, or they can be configured to operate as one 32-bit timer or one

32-bit Real Time Clock (RTC). For the purpose of this API, the two timers provided by the timer are referred to as TimerA and TimerB.

When configured as either a 32-bit or 16-bit timer, a timer can be set up to run as a one-shot timer or a continuous timer. If configured as a one-shot timer, when it reaches zero the timer will cease counting. If configured as a continuous timer, when it reaches zero the timer will continue counting from a reloaded value. When configured as a 32-bit timer, the timer can also be configured to operate as an RTC. In that case, the timer expects to be driven by a 32 KHz external clock, which is divided down to produce 1 second clock ticks.

When in 16-bit mode, the timer can also be configured for event capture or as a Pulse Width

Modulation (PWM) generator. When configured for event capture, the timer acts as a counter. It can be configured to either count the time between events, or it can count the events themselves.

The type of event being counted can be configured as a positive edge, a negative edge, or both edges. When a timer is configured as a PWM generator, the input line used to capture events becomes an output line, and the timer is used to drive an edge-aligned pulse onto that line.

The timer module also provides the ability to control other functional parameters, such as output inversion, output triggers, and timer behavior during stalls.

Control is also provided over interrupt sources and events. Interrupts can be generated to indicate that an event has been captured, or that a certain number of events have been captured. Interrupts can also be generated when the timer has counted down to zero, or when the RTC matches a certain value.

16.2

API Functions

Functions void

TimerConfigure

(unsigned long ulBase, unsigned long ulConfig) void

TimerControlEvent

(unsigned long ulBase, unsigned long ulTimer, unsigned long ulEvent) void

TimerControlLevel

(unsigned long ulBase, unsigned long ulTimer, tBoolean bInvert) void

TimerControlStall

(unsigned long ulBase, unsigned long ulTimer, tBoolean bStall) void

TimerControlTrigger

(unsigned long ulBase, unsigned long ulTimer, tBoolean bEnable) void

TimerDisable

(unsigned long ulBase, unsigned long ulTimer)

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Timer void

TimerEnable

(unsigned long ulBase, unsigned long ulTimer) void

TimerIntClear


TimerIntDisable


TimerIntEnable


TimerIntRegister

(unsigned long ulBase, unsigned long ulTimer, void (∗pfnHandler)(void)) unsigned long

TimerIntStatus


TimerIntUnregister

(unsigned long ulBase, unsigned long ulTimer) unsigned long

TimerLoadGet


TimerLoadSet

(unsigned long ulBase, unsigned long ulTimer, unsigned long ulValue) unsigned long

TimerMatchGet


TimerMatchSet

(unsigned long ulBase, unsigned long ulTimer, unsigned long ulValue) unsigned long

TimerPrescaleGet

(unsigned long ulBase, unsigned long ulTimer) unsigned long

TimerPrescaleMatchGet


TimerPrescaleMatchSet

(unsigned long ulBase, unsigned long ulTimer, unsigned long ulValue) void

TimerPrescaleSet

(unsigned long ulBase, unsigned long ulTimer, unsigned long ulValue) void

TimerQuiesce


TimerRTCDisable


TimerRTCEnable


TimerValueGet

(unsigned long ulBase, unsigned long ulTimer)

16.2.1


The timer API is broken into three groups of functions: those that deal with timer configuration and control, those that deal with timer contents, and those that deal with interrupt handling.

Timer configuration is handled by

TimerConfigure() , which performs the high level setup of

the timer module; that is, it is used to set up 32- or 16-bit modes, and to select between

PWM, capture, and timer operations.

Timer control is performed by

TimerEnable() , Timer-

Disable() ,

TimerControlLevel() , TimerControlTrigger() ,

TimerControlEvent() ,

TimerControlStall() ,

TimerRTCEnable() ,

TimerRTCDisable() , and TimerQuiesce() .

Timer content is managed with

TimerLoadSet() , TimerLoadGet() ,

TimerPrescaleSet() ,

Timer-

PrescaleGet() , TimerMatchSet() ,

TimerMatchGet() ,

TimerPrescaleMatchSet() , TimerPrescale-

MatchGet() , and

TimerValueGet() .

The interrupt handler for the Timer interrupt is managed with

TimerIntRegister()

and

TimerInt-

Unregister() . The individual interrupt sources within the timer module are managed with

Timer-

IntEnable() ,

TimerIntDisable() ,

TimerIntStatus() , and

TimerIntClear() .

16.2.2


16.2.2.1 TimerConfigure

Configures the timer(s).

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Prototype:

void

TimerConfigure(unsigned long ulBase, unsigned long ulConfig)

Parameters:

ulBase is the base address of the timer module.

ulConfig is the configuration for the timer.

Description:

This function configures the operating mode of the timer(s). The timer module is disabled before being configured, and is left in the disabled state. The configuration is specified in ulConfig as one of the following values:

TIMER_CFG_32_BIT_OS - 32-bit one shot timer

TIMER_CFG_32_BIT_PER - 32-bit periodic timer

TIMER_CFG_32_RTC - 32-bit real time clock timer

TIMER_CFG_16_BIT_PAIR - Two 16-bit timers

When configured for a pair of 16-bit timers, each timer is separately configured. The first timer is configured by setting ulConfig to the result of a logical OR operation between one of the following values and ulConfig:

TIMER_CFG_A_ONE_SHOT - 16-bit one shot timer

TIMER_CFG_A_PERIODIC - 16-bit periodic timer

TIMER_CFG_A_CAP_COUNT - 16-bit edge count capture

TIMER_CFG_A_CAP_TIME - 16-bit edge time capture

TIMER_CFG_A_PWM - 16-bit PWM output

Similarly, the second timer is configured by setting ulConfig to the result of a logical OR operation between one of the corresponding TIMER_CFG_B_∗ values and ulConfig.

Returns:

None.

16.2.2.2 TimerControlEvent

Controls the event type.

Prototype:

void

TimerControlEvent(unsigned long ulBase, unsigned long ulTimer, unsigned long ulEvent)

Parameters:


ulTimer specifies the timer(s) to be adjusted; must be one of TIMER_A, TIMER_B, or

TIMER_BOTH.

ulEvent specifies the type of event; must be one of TIMER_EVENT_POS_EDGE, TIMER_-

EVENT_NEG_EDGE, or TIMER_EVENT_BOTH_EDGES.

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Description:

This function sets the signal edge(s) that will trigger the timer when in capture mode.

Returns:

None.

16.2.2.3 TimerControlLevel

Controls the output level.

Prototype:

void

TimerControlLevel(unsigned long ulBase, unsigned long ulTimer, tBoolean bInvert)

Parameters:


ulTimer specifies the timer(s) to adjust; must be one of TIMER_A, TIMER_B, or TIMER_-

BOTH.

bInvert specifies the output level.

Description:

This function sets the PWM output level for the specified timer. If the parameter bInvert is

true, then the timer’s output will be made active low; otherwise, it will be made active high.

Returns:

None.

16.2.2.4 TimerControlStall

Controls the stall handling.

Prototype:

void

TimerControlStall(unsigned long ulBase, unsigned long ulTimer, tBoolean bStall)

Parameters:


ulTimer specifies the timer(s) to be adjusted; must be one of TIMER_A, TIMER_B, or

TIMER_BOTH.

bStall specifies the response to a stall signal.

Description:

This function controls the stall response for the specified timer. If the parameter bStall is true, then the timer will stop counting if the processor enters debug mode; otherwise the timer will keep running while in debug mode.

Returns:

None.

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16.2.2.5 TimerControlTrigger

Enables or disables the trigger output.

Prototype:

void

TimerControlTrigger(unsigned long ulBase, unsigned long ulTimer, tBoolean bEnable)

Parameters:


ulTimer specifies the timer to adjust; must be one of TIMER_A, TIMER_B, or TIMER_BOTH.

bEnable specifies the desired trigger state.

Description:

This function controls the trigger output for the specified timer. If the parameter bEnable is

true, then the timer’s output trigger is enabled; otherwise it is disabled.

Returns:

None.

16.2.2.6 TimerDisable

Disables the timer(s).

Prototype:

void

TimerDisable(unsigned long ulBase, unsigned long ulTimer)

Parameters:


ulTimer specifies the timer(s) to disable; must be one of TIMER_A, TIMER_B, or TIMER_-

BOTH.

Description:

This will disable operation of the timer module.

Returns:

None.

16.2.2.7 TimerEnable

Enables the timer(s).

Prototype:

void

TimerEnable(unsigned long ulBase, unsigned long ulTimer)

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Parameters:


ulTimer specifies the timer(s) to enable; must be one of TIMER_A, TIMER_B, or TIMER_-

BOTH.

Description:

This will enable operation of the timer module. The timer must be configured before it is enabled.

Returns:

None.

16.2.2.8 TimerIntClear

Clears timer interrupt sources.

Prototype:

void

TimerIntClear(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

The specified timer interrupt sources are cleared, so that they no longer assert. This must be done in the interrupt handler to keep it from being called again immediately upon exit.

The parameter ulIntFlags has the same definition as the ulIntFlags parameter to

TimerInt-

Enable() .

Returns:

None.

16.2.2.9 TimerIntDisable

Disables individual timer interrupt sources.

Prototype:

void

TimerIntDisable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

Disables the indicated timer interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.

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The parameter ulIntFlags has the same definition as the ulIntFlags parameter to

TimerInt-

Enable() .

Returns:

None.

16.2.2.10 TimerIntEnable

Enables individual timer interrupt sources.

Prototype:

void

TimerIntEnable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

Enables the indicated timer interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.

The parameter ulIntFlags must be the logical OR of any combination of the following:

TIMER_CAPB_EVENT - Capture B event interrupt

TIMER_CAPB_MATCH - Capture B match interrupt

TIMER_TIMB_TIMEOUT - Timer B timeout interrupt

TIMER_RTC_MATCH - RTC interrupt mask

TIMER_CAPA_EVENT - Capture A event interrupt

TIMER_CAPA_MATCH - Capture A match interrupt

TIMER_TIMA_TIMEOUT - Timer A timeout interrupt

Returns:

None.

16.2.2.11 TimerIntRegister

Registers an interrupt handler for the timer interrupt.

Prototype:

void

TimerIntRegister(unsigned long ulBase, unsigned long ulTimer, void (*pfnHandler)(void))

Parameters:


ulTimer specifies the timer(s); must be one of TIMER_A, TIMER_B, or TIMER_BOTH.

pfnHandler is a pointer to the function to be called when the timer interrupt occurs.

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Description:

This sets the handler to be called when a timer interrupt occurs. This will enable the global interrupt in the interrupt controller; specific timer interrupts must be enabled via

TimerIntEnable() .

It is the interrupt handler’s responsibility to clear the interrupt source via

TimerIntClear() .

See also:

IntRegister()


Returns:

None.

16.2.2.12 TimerIntStatus


Prototype:

unsigned long

TimerIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:



Description:

This returns the interrupt status for the timer module. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:


TimerIntEnable() .

16.2.2.13 TimerIntUnregister

Unregisters an interrupt handler for the timer interrupt.

Prototype:

void

TimerIntUnregister(unsigned long ulBase, unsigned long ulTimer)

Parameters:


ulTimer specifies the timer(s); must be one of TIMER_A, TIMER_B, or TIMER_BOTH.

Description:

This function will clear the handler to be called when a timer interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

See also:

IntRegister()


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Returns:

None.

16.2.2.14 TimerLoadGet

Gets the timer load value.

Prototype:

unsigned long

TimerLoadGet(unsigned long ulBase, unsigned long ulTimer)

Parameters:


ulTimer specifies the timer; must be one of TIMER_A or TIMER_B. Only TIMER_A should be used when the timer is configured for 32-bit operation.

Description:

This function gets the currently programmed interval load value for the specified timer.

Returns:

Returns the load value for the timer.

16.2.2.15 TimerLoadSet

Sets the timer load value.

Prototype:

void

TimerLoadSet(unsigned long ulBase, unsigned long ulTimer, unsigned long ulValue)

Parameters:



BOTH. Only TIMER_A should be used when the timer is configured for 32-bit operation.

ulValue is the load value.

Description:

This function sets the timer load value; if the timer is running then the value will be immediately loaded into the timer.

Returns:

None.

16.2.2.16 TimerMatchGet

Gets the timer match value.

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Timer

Prototype:

unsigned long

TimerMatchGet(unsigned long ulBase, unsigned long ulTimer)

Parameters:



Description:

This function gets the match value for the specified timer.

Returns:

Returns the match value for the timer.

16.2.2.17 TimerMatchSet

Sets the timer match value.

Prototype:

void

TimerMatchSet(unsigned long ulBase, unsigned long ulTimer, unsigned long ulValue)

Parameters:



BOTH. Only TIMER_A should be used when the timer is configured for 32-bit operation.

ulValue is the match value.

Description:

This function sets the match value for a timer. This is used in capture count mode to determine when to interrupt the processor and in PWM mode to determine the duty cycle of the output signal.

Returns:

None.

16.2.2.18 TimerPrescaleGet

Get the timer prescale value.

Prototype:

unsigned long

TimerPrescaleGet(unsigned long ulBase, unsigned long ulTimer)

Parameters:


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ulTimer specifies the timer; must be one of TIMER_A or TIMER_B.

Description:

This function gets the value of the input clock prescaler. The prescaler is only operational when in 16-bit mode and is used to extend the range of the 16-bit timer modes.

Returns:

The value of the timer prescaler.

16.2.2.19 TimerPrescaleMatchGet

Get the timer prescale match value.

Prototype:

unsigned long

TimerPrescaleMatchGet(unsigned long ulBase, unsigned long ulTimer)

Parameters:


ulTimer specifies the timer; must be one of TIMER_A or TIMER_B.

Description:

This function gets the value of the input clock prescaler match value. When in a 16-bit mode that uses the counter match (edge count or PWM), the prescale match effectively extends the range of the counter to 24-bits.

Returns:

The value of the timer prescale match.

16.2.2.20 TimerPrescaleMatchSet

Set the timer prescale match value.

Prototype:

void

TimerPrescaleMatchSet(unsigned long ulBase, unsigned long ulTimer, unsigned long ulValue)

Parameters:



BOTH.

ulValue is the timer prescale match value; must be between 0 and 255, inclusive.

Description:

This function sets the value of the input clock prescaler match value. When in a 16-bit mode that uses the counter match (edge count or PWM), the prescale match effectively extends the range of the counter to 24-bits.

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Timer

Returns:

None.

16.2.2.21 TimerPrescaleSet

Set the timer prescale value.

Prototype:

void

TimerPrescaleSet(unsigned long ulBase, unsigned long ulTimer, unsigned long ulValue)

Parameters:



BOTH.

ulValue is the timer prescale value; must be between 0 and 255, inclusive.

Description:

This function sets the value of the input clock prescaler. The prescaler is only operational when in 16-bit mode and is used to extend the range of the 16-bit timer modes.

Returns:

None.

16.2.2.22 TimerQuiesce

Puts the timer into its reset state.

Prototype:

void

TimerQuiesce(unsigned long ulBase)

Parameters:


Description:

The specified timer is disabled, and all its interrupts are disabled, cleared, and unregistered.

Then the timer registers are set to their reset value.

Returns:

None.

16.2.2.23 TimerRTCDisable

Disable RTC counting.

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Prototype:

void

TimerRTCDisable(unsigned long ulBase)

Parameters:


Description:

This function causes the timer to stop counting when in RTC mode.

Returns:

None.

16.2.2.24 TimerRTCEnable

Enable RTC counting.

Prototype:

void

TimerRTCEnable(unsigned long ulBase)

Parameters:


Description:

This function causes the timer to start counting when in RTC mode. If not configured for RTC mode, this will do nothing.

Returns:

None.

16.2.2.25 TimerValueGet

Gets the current timer value.

Prototype:

unsigned long

TimerValueGet(unsigned long ulBase, unsigned long ulTimer)

Parameters:



Description:

This function reads the current value of the specified timer.

Returns:

Returns the current value of the timer.

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16.3


The following example shows how to use the timer API to configure the timer as a 16-bit one shot timer and a 16-bit edge capture counter.

//

// Configure TimerA as a 16-bit one shot timer, and TimerB as a 16-bit edge

// capture counter.

//

TimerConfigure(TIMER0_BASE, (TIMER_CFG_16_BIT_PAIR | TIMER_CFG_A_ONE_SHOT |

TIMER_CFG_B_CAP_COUNT));

//

// Configure the counter (TimerB) to count both edges.

//

TimerControlEvent(TIMER0_BASE, TIMER_B, TIMER_EVENT_BOTH_EDGES);

//

// Enable the timers.

//

TimerEnable(TIMER0_BASE, TIMER_BOTH);

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17 UART

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213


17.1

Introduction

The Universal Asynchronous Receiver/Transmitter (UART) API provides a set of functions for using the Stellaris UART modules. Functions are provided to configure and control the UART modules, to send and receive data, and to manage interrupts for the UART modules.

The Stellaris UART performs the functions of parallel-to-serial and serial-to-parallel conversions. It is very similar in functionality to a 16C550 UART, but is not register-compatible.

Some of the features of the Stellaris UART are:

A 16x12 bit receive FIFO and a 16x8 bit transmit FIFO.

Programmable baud rate generator.

Automatic generation and stripping of start, stop, and parity bits.

Line break generation and detection.

Programmable serial interface

• 5, 6, 7, or 8 data bits

• even, odd, stick, or no parity bit generation and detection

• 1 or 2 stop bit generation

• baud rate generation, from DC to processor clock/16

IrDA serial-IR (SIR) encoder/decoder.

17.2

API Functions

Functions void

UARTBreakCtl

(unsigned long ulBase, tBoolean bBreakState) long

UARTCharGet

(unsigned long ulBase) long

UARTCharGetNonBlocking


UARTCharPut

(unsigned long ulBase, unsigned char ucData) tBoolean

UARTCharPutNonBlocking

(unsigned long ulBase, unsigned char ucData) tBoolean

UARTCharsAvail


UARTConfigGetExpClk

(unsigned long ulBase, unsigned long ulUARTClk, unsigned long

∗pulBaud, unsigned long ∗pulConfig) void

UARTConfigSetExpClk

(unsigned long ulBase, unsigned long ulUARTClk, unsigned long ulBaud, unsigned long ulConfig) void

UARTDisable


UARTDisableSIR


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UART void

UARTEnable


UARTEnableSIR

(unsigned long ulBase, tBoolean bLowPower) void

UARTFIFOLevelGet

(unsigned long ulBase, unsigned long ∗pulTxLevel, unsigned long

∗pulRxLevel) void

UARTFIFOLevelSet

(unsigned long ulBase, unsigned long ulTxLevel, unsigned long ul-

RxLevel) void

UARTIntClear


UARTIntDisable


UARTIntEnable


UARTIntRegister


UARTIntStatus


UARTIntUnregister


UARTParityModeGet


UARTParityModeSet

(unsigned long ulBase, unsigned long ulParity) tBoolean

UARTSpaceAvail


17.2.1


The UART API provides the set of functions required to implement an interrupt driven UART driver.

These functions may be used to control any of the available UART ports on a Stellaris microcontroller, and can be used with one port without causing conflicts with the other port.

The UART API is broken into three groups of functions: those that deal with configuration and control of the UART modules, those used to send and receive data, and those that deal with interrupt handling.

Configuration and control of the UART are handled by the

UARTConfigGetExpClk() , UARTConfig-

SetExpClk() ,

UARTDisable() ,

UARTEnable() ,

UARTParityModeGet() , and

UARTParityModeSet()

functions.

Sending and receiving data via the UART is handled by the

UARTCharGet() , UARTCharGet-

NonBlocking() ,

UARTCharPut() , UARTCharPutNonBlocking() ,

UARTBreakCtl() ,

UARTCharsAvail() ,

and

UARTSpaceAvail()

functions.

Managing the UART interrupts is handled by the

UARTIntClear() , UARTIntDisable() ,

UARTInt-

Enable() , UARTIntRegister() ,

UARTIntStatus() , and UARTIntUnregister()

functions.

The UARTConfigSet(), UARTConfigGet(), UARTCharNonBlockingGet(), and UARTCharNon-

BlockingPut() APIs from previous versions of the Peripheral Driver Library have been replaced by the

UARTConfigSetExpClk() , UARTConfigGetExpClk() ,

UARTCharGetNonBlocking() ,

and

UARTCharPutNonBlocking()

APIs, respectively. Macros have been provided in uart.h to map the old APIs to the new APIs, allowing existing applications to link and run with the new APIs.

It is recommended that new applications utilize the new APIs in favor of the old ones.

17.2.2


17.2.2.1 UARTBreakCtl

Causes a BREAK to be sent.

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Prototype:

void

UARTBreakCtl(unsigned long ulBase, tBoolean bBreakState)

Parameters:

ulBase is the base address of the UART port.

bBreakState controls the output level.

Description:

Calling this function with bBreakState set to true will assert a break condition on the UART.

Calling this function with bBreakState set to

false will remove the break condition. For proper transmission of a break command, the break must be asserted for at least two complete frames.

Returns:

None.

17.2.2.2 UARTCharGet

Waits for a character from the specified port.

Prototype:

long

UARTCharGet(unsigned long ulBase)

Parameters:


Description:

Gets a character from the receive FIFO for the specified port. If there are no characters available, this function will wait until a character is received before returning.

Returns:

Returns the character read from the specified port, cast as an int.

17.2.2.3 UARTCharGetNonBlocking

Receives a character from the specified port.

Prototype:

long

UARTCharGetNonBlocking(unsigned long ulBase)

Parameters:


Description:

Gets a character from the receive FIFO for the specified port.

This function replaces the original UARTCharNonBlockingGet() API and performs the same actions. A macro is provided in uart.h to map the original API to this API.

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UART

Returns:

Returns the character read from the specified port, cast as a long. A -1 will be returned if there are no characters present in the receive FIFO. The

UARTCharsAvail()

function should be called before attempting to call this function.

17.2.2.4 UARTCharPut

Waits to send a character from the specified port.

Prototype:

void

UARTCharPut(unsigned long ulBase, unsigned char ucData)

Parameters:


ucData is the character to be transmitted.

Description:

Sends the character ucData to the transmit FIFO for the specified port. If there is no space available in the transmit FIFO, this function will wait until there is space available before returning.

Returns:

None.

17.2.2.5 UARTCharPutNonBlocking

Sends a character to the specified port.

Prototype:

tBoolean

UARTCharPutNonBlocking(unsigned long ulBase, unsigned char ucData)

Parameters:


ucData is the character to be transmitted.

Description:

Writes the character ucData to the transmit FIFO for the specified port. This function does not block, so if there is no space available, then a false is returned, and the application will have to retry the function later.

This function replaces the original UARTCharNonBlockingPut() API and performs the same actions. A macro is provided in uart.h to map the original API to this API.

Returns:

Returns true if the character was successfully placed in the transmit FIFO, and false if there was no space available in the transmit FIFO.

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17.2.2.6 UARTCharsAvail

Determines if there are any characters in the receive FIFO.

Prototype:

tBoolean

UARTCharsAvail(unsigned long ulBase)

Parameters:


Description:

This function returns a flag indicating whether or not there is data available in the receive FIFO.

Returns:

Returns true if there is data in the receive FIFO, and false if there is no data in the receive

FIFO.

17.2.2.7 UARTConfigGetExpClk

Gets the current configuration of a UART.

Prototype:

void

UARTConfigGetExpClk(unsigned long ulBase, unsigned long ulUARTClk, unsigned long *pulBaud, unsigned long *pulConfig)

Parameters:


ulUARTClk is the rate of the clock supplied to the UART module.

pulBaud is a pointer to storage for the baud rate.

pulConfig is a pointer to storage for the data format.

Description:

The baud rate and data format for the UART is determined, given an explicitly provided peripheral clock (hence the ExpClk suffix). The returned baud rate is the actual baud rate; it may not be the exact baud rate requested or an “official” baud rate. The data format returned in pulConfig is enumerated the same as the ulConfig parameter of

UARTConfigSetExpClk() .




SysCtlClockGet() ).

This function replaces the original UARTConfigGet() API and performs the same actions. A macro is provided in uart.h to map the original API to this API.

Returns:

None.

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UART

17.2.2.8 UARTConfigSetExpClk

Sets the configuration of a UART.

Prototype:

void

UARTConfigSetExpClk(unsigned long ulBase, unsigned long ulUARTClk, unsigned long ulBaud, unsigned long ulConfig)

Parameters:


ulUARTClk is the rate of the clock supplied to the UART module.

ulBaud is the desired baud rate.

ulConfig is the data format for the port (number of data bits, number of stop bits, and parity).

Description:

This function will configure the UART for operation in the specified data format. The baud rate is provided in the ulBaud parameter and the data format in the ulConfig parameter.

The ulConfig parameter is the logical OR of three values: the number of data bits, the number of stop bits, and the parity.

UART_CONFIG_WLEN_8, UART_CONFIG_WLEN_7, UART_-

CONFIG_WLEN_6, and UART_CONFIG_WLEN_5 select from eight to five data bits per byte

(respectively).

UART_CONFIG_STOP_ONE and UART_CONFIG_STOP_TWO select one or two stop bits (respectively).

UART_CONFIG_PAR_NONE, UART_CONFIG_PAR_EVEN,

UART_CONFIG_PAR_ODD, UART_CONFIG_PAR_ONE, and UART_CONFIG_PAR_ZERO select the parity mode (no parity bit, even parity bit, odd parity bit, parity bit always one, and parity bit always zero, respectively).




SysCtlClockGet() ).

This function replaces the original UARTConfigSet() API and performs the same actions. A macro is provided in uart.h to map the original API to this API.

Returns:

None.

17.2.2.9 UARTDisable

Disables transmitting and receiving.

Prototype:

void

UARTDisable(unsigned long ulBase)

Parameters:


Description:

Clears the UARTEN, TXE, and RXE bits, then waits for the end of transmission of the current character, and flushes the transmit FIFO.

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Returns:

None.

17.2.2.10 UARTDisableSIR

Disables SIR (IrDA) mode on the specified UART.

Prototype:

void

UARTDisableSIR(unsigned long ulBase)

Parameters:


Description:

Clears the SIREN (IrDA) and SIRLP (Low Power) bits.

Note:

SIR (IrDA) operation is supported only on Fury-class devices.

Returns:

None.

17.2.2.11 UARTEnable

Enables transmitting and receiving.

Prototype:

void

UARTEnable(unsigned long ulBase)

Parameters:


Description:

Sets the UARTEN, TXE, and RXE bits, and enables the transmit and receive FIFOs.

Returns:

None.

17.2.2.12 UARTEnableSIR

Enables SIR (IrDA) mode on specified UART.

Prototype:

void

UARTEnableSIR(unsigned long ulBase, tBoolean bLowPower)

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UART

Parameters:


bLowPower indicates if SIR Low Power Mode is to be used.

Description:

Enables the SIREN control bit for IrDA mode on the UART. If the bLowPower flag is set, then

SIRLP bit will also be set.

Note:

SIR (IrDA) operation is supported only on Fury-class devices.

Returns:

None.

17.2.2.13 UARTFIFOLevelGet

Gets the FIFO level at which interrupts are generated.

Prototype:

void

UARTFIFOLevelGet(unsigned long ulBase, unsigned long *pulTxLevel, unsigned long *pulRxLevel)

Parameters:


pulTxLevel is a pointer to storage for the transmit FIFO level, returned as one of

UART_FIFO_TX1_8, UART_FIFO_TX2_8, UART_FIFO_TX4_8, UART_FIFO_TX6_8, or

UART_FIFO_TX7_8.

pulRxLevel is a pointer to storage for the receive FIFO level, returned as one of UART_FIFO_-

RX1_8, UART_FIFO_RX2_8, UART_FIFO_RX4_8, UART_FIFO_RX6_8, or UART_-

FIFO_RX7_8.

Description:

This function gets the FIFO level at which transmit and receive interrupts will be generated.

Returns:

None.

17.2.2.14 UARTFIFOLevelSet

Sets the FIFO level at which interrupts are generated.

Prototype:

void

UARTFIFOLevelSet(unsigned long ulBase, unsigned long ulTxLevel, unsigned long ulRxLevel)

Parameters:


222 October 11, 2007


ulTxLevel is the transmit FIFO interrupt level, specified as one of UART_FIFO_TX1_8,

UART_FIFO_TX2_8, UART_FIFO_TX4_8, UART_FIFO_TX6_8, or UART_FIFO_TX7_8.

ulRxLevel is the receive FIFO interrupt level, specified as one of UART_FIFO_RX1_8,

UART_FIFO_RX2_8, UART_FIFO_RX4_8, UART_FIFO_RX6_8, or UART_FIFO_RX7_8.

Description:

This function sets the FIFO level at which transmit and receive interrupts will be generated.

Returns:

None.

17.2.2.15 UARTIntClear

Clears UART interrupt sources.

Prototype:

void

UARTIntClear(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

The specified UART interrupt sources are cleared, so that they no longer assert. This must be done in the interrupt handler to keep it from being called again immediately upon exit.


UARTIntEnable() .

Returns:

None.

17.2.2.16 UARTIntDisable

Disables individual UART interrupt sources.

Prototype:

void

UARTIntDisable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

Disables the indicated UART interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.


UARTIntEnable() .

October 11, 2007 223

UART

Returns:

None.

17.2.2.17 UARTIntEnable

Enables individual UART interrupt sources.

Prototype:

void

UARTIntEnable(unsigned long ulBase, unsigned long ulIntFlags)

Parameters:



Description:

Enables the indicated UART interrupt sources. Only the sources that are enabled can be reflected to the processor interrupt; disabled sources have no effect on the processor.


UART_INT_OE - Overrun Error interrupt

UART_INT_BE - Break Error interrupt

UART_INT_PE - Parity Error interrupt

UART_INT_FE - Framing Error interrupt

UART_INT_RT - Receive Timeout interrupt

UART_INT_TX - Transmit interrupt

UART_INT_RX - Receive interrupt

Returns:

None.

17.2.2.18 UARTIntRegister

Registers an interrupt handler for a UART interrupt.

Prototype:

void

UARTIntRegister(unsigned long ulBase, void (*pfnHandler)(void))

Parameters:


pfnHandler is a pointer to the function to be called when the UART interrupt occurs.

Description:

This function does the actual registering of the interrupt handler. This will enable the global interrupt in the interrupt controller; specific UART interrupts must be enabled via

UARTInt-

Enable() . It is the interrupt handler’s responsibility to clear the interrupt source.

224 October 11, 2007


See also:

IntRegister()


Returns:

None.

17.2.2.19 UARTIntStatus


Prototype:

unsigned long

UARTIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:



Description:

This returns the interrupt status for the specified UART. Either the raw interrupt status or the status of interrupts that are allowed to reflect to the processor can be returned.

Returns:


UARTIntEnable() .

17.2.2.20 UARTIntUnregister

Unregisters an interrupt handler for a UART interrupt.

Prototype:

void

UARTIntUnregister(unsigned long ulBase)

Parameters:


Description:

This function does the actual unregistering of the interrupt handler. It will clear the handler to be called when a UART interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

See also:

IntRegister()


Returns:

None.

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17.2.2.21 UARTParityModeGet

Gets the type of parity currently being used.

Prototype:

unsigned long

UARTParityModeGet(unsigned long ulBase)

Parameters:


Description:

This function gets the type of parity used for transmitting data, and expected when receiving data.

Returns:

The current parity settings, specified as one of UART_CONFIG_PAR_NONE, UART_-

CONFIG_PAR_EVEN, UART_CONFIG_PAR_ODD, UART_CONFIG_PAR_ONE, or UART_-

CONFIG_PAR_ZERO.

17.2.2.22 UARTParityModeSet

Sets the type of parity.

Prototype:

void

UARTParityModeSet(unsigned long ulBase, unsigned long ulParity)

Parameters:


ulParity specifies the type of parity to use.

Description:

Sets the type of parity to use for transmitting and expect when receiving. The ulParity parameter must be one of UART_CONFIG_PAR_NONE, UART_CONFIG_PAR_EVEN, UART_-

CONFIG_PAR_ODD, UART_CONFIG_PAR_ONE, or UART_CONFIG_PAR_ZERO. The last two allow direct control of the parity bit; it will always be either be one or zero based on the mode.

Returns:

None.

17.2.2.23 UARTSpaceAvail

Determines if there is any space in the transmit FIFO.

Prototype:

tBoolean

UARTSpaceAvail(unsigned long ulBase)

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Parameters:


Description:

This function returns a flag indicating whether or not there is space available in the transmit

FIFO.

Returns:

Returns true if there is space available in the transmit FIFO, and false if there is no space available in the transmit FIFO.

17.3


The following example shows how to use the UART API to initialize the UART, transmit characters, and receive characters.

//

// Initialize the UART.

Set the baud rate, number of data bits, turn off

// parity, number of stop bits, and stick mode.

//

UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), 38400,

(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |

UART_CONFIG_PAR_NONE));

//

// Enable the UART.

//

UARTEnable(UART0_BASE);

//

// Check for characters.

This will spin here until a character is placed

// into the receive FIFO.

// while(!UARTCharsAvail(UART0_BASE))

{

}

//

// Get the character(s) in the receive FIFO.

// while(UARTCharGetNonBlocking(UART0_BASE))

{

}

//

// Put a character in the output buffer.

//

UARTCharPut(UART0_BASE, ’c’));

//

// Disable the UART.

//

UARTDisable(UART0_BASE);

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18 Watchdog Timer

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227


18.1

Introduction

The Watchdog Timer API provides a set of functions for using the Stellaris watchdog timer modules. Functions are provided to deal with the watchdog timer interrupts, and to handle status and configuration of the watchdog timer.

The watchdog timer module’s function is to prevent system hangs. The watchdog timer module consists of a 32-bit down counter, a programmable load register, interrupt generation logic, and a locking register. Once the watchdog timer has been configured, the lock register can be written to prevent the timer configuration from being inadvertently altered.

The watchdog timer can be configured to generate an interrupt to the processor upon its first timeout, and to generate a reset signal upon its second timeout. The watchdog timer module generates the first timeout signal when the 32-bit counter reaches the zero state after being enabled; enabling the counter also enables the watchdog timer interrupt. After the first timeout event, the 32-bit counter is reloaded with the value of the watchdog timer load register, and the timer resumes counting down from that value. If the timer counts down to its zero state again before the first timeout interrupt is cleared, and the reset signal has been enabled, the watchdog timer asserts its reset signal to the system. If the interrupt is cleared before the 32-bit counter reaches its second timeout, the 32-bit counter is loaded with the value in the load register, and counting resumes from that value. If the load register is written with a new value while the watchdog timer counter is counting, then the counter is loaded with the new value and continues counting.

18.2

API Functions

Functions void

WatchdogEnable


WatchdogIntClear


WatchdogIntEnable


WatchdogIntRegister


WatchdogIntStatus


WatchdogIntUnregister


WatchdogLock


WatchdogLockState


WatchdogReloadGet


WatchdogReloadSet

(unsigned long ulBase, unsigned long ulLoadVal) void

WatchdogResetDisable


WatchdogResetEnable


WatchdogRunning


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Watchdog Timer void

WatchdogStallDisable


WatchdogStallEnable


WatchdogUnlock


WatchdogValueGet


18.2.1


The Watchdog Timer API is broken into two groups of functions: those that deal with interrupts, and those that handle status and configuration.

The Watchdog Timer interrupts are handled by the

WatchdogIntRegister() ,

WatchdogInt-

Unregister() ,

WatchdogIntEnable() ,

WatchdogIntClear() , and

WatchdogIntStatus()

functions.

Status and configuration functions for the Watchdog Timer module are

WatchdogEnable() ,

WatchdogRunning() ,

WatchdogLock() ,

WatchdogUnlock() ,

WatchdogLockState() ,

Watchdog-

ReloadSet() ,

WatchdogReloadGet() ,

WatchdogValueGet() ,

WatchdogResetEnable() ,

Watchdog-

ResetDisable() ,

WatchdogStallEnable() , and

WatchdogStallDisable() .

18.2.2


18.2.2.1 WatchdogEnable

Enables the watchdog timer.

Prototype:

void

WatchdogEnable(unsigned long ulBase)

Parameters:

ulBase is the base address of the watchdog timer module.

Description:

This will enable the watchdog timer counter and interrupt.

Note:

This function will have no effect if the watchdog timer has been locked.

See also:

WatchdogLock() ,

WatchdogUnlock()

Returns:

None.

18.2.2.2 WatchdogIntClear

Clears the watchdog timer interrupt.

Prototype:

void

WatchdogIntClear(unsigned long ulBase)

230 October 11, 2007


Parameters:


Description:

The watchdog timer interrupt source is cleared, so that it no longer asserts.

Returns:

None.

18.2.2.3 WatchdogIntEnable

Enables the watchdog timer interrupt.

Prototype:

void

WatchdogIntEnable(unsigned long ulBase)

Parameters:


Description:

Enables the watchdog timer interrupt.

Note:


See also:

WatchdogLock() ,

WatchdogUnlock() ,

WatchdogEnable()

Returns:

None.

18.2.2.4 WatchdogIntRegister

Registers an interrupt handler for watchdog timer interrupt.

Prototype:

void

WatchdogIntRegister(unsigned long ulBase, void (*pfnHandler)(void))

Parameters:


pfnHandler is a pointer to the function to be called when the watchdog timer interrupt occurs.

Description:

This function does the actual registering of the interrupt handler. This will enable the global interrupt in the interrupt controller; the watchdog timer interrupt must be enabled via

Watchdog-

Enable() . It is the interrupt handler’s responsibility to clear the interrupt source via Watchdog-

IntClear() .

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Watchdog Timer

See also:

IntRegister()


Returns:

None.

18.2.2.5 WatchdogIntStatus

Gets the current watchdog timer interrupt status.

Prototype:

unsigned long

WatchdogIntStatus(unsigned long ulBase, tBoolean bMasked)

Parameters:


bMasked is false if the raw interrupt status is required and true if the masked interrupt status is required.

Description:

This returns the interrupt status for the watchdog timer module. Either the raw interrupt status or the status of interrupt that is allowed to reflect to the processor can be returned.

Returns:

The current interrupt status, where a 1 indicates that the watchdog interrupt is active, and a 0 indicates that it is not active.

18.2.2.6 WatchdogIntUnregister

Unregisters an interrupt handler for the watchdog timer interrupt.

Prototype:

void

WatchdogIntUnregister(unsigned long ulBase)

Parameters:


Description:

This function does the actual unregistering of the interrupt handler. This function will clear the handler to be called when a watchdog timer interrupt occurs. This will also mask off the interrupt in the interrupt controller so that the interrupt handler no longer is called.

See also:

IntRegister()


Returns:

None.

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18.2.2.7 WatchdogLock

Enables the watchdog timer lock mechanism.

Prototype:

void

WatchdogLock(unsigned long ulBase)

Parameters:


Description:

Locks out write access to the watchdog timer configuration registers.

Returns:

None.

18.2.2.8 WatchdogLockState

Gets the state of the watchdog timer lock mechanism.

Prototype:

tBoolean

WatchdogLockState(unsigned long ulBase)

Parameters:


Description:

Returns the lock state of the watchdog timer registers.

Returns:

Returns true if the watchdog timer registers are locked, and false if they are not locked.

18.2.2.9 WatchdogReloadGet

Gets the watchdog timer reload value.

Prototype:

unsigned long

WatchdogReloadGet(unsigned long ulBase)

Parameters:


Description:

This function gets the value that is loaded into the watchdog timer when the count reaches zero for the first time.

See also:

WatchdogReloadSet()

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Watchdog Timer

Returns:

None.

18.2.2.10 WatchdogReloadSet

Sets the watchdog timer reload value.

Prototype:

void

WatchdogReloadSet(unsigned long ulBase, unsigned long ulLoadVal)

Parameters:


ulLoadVal is the load value for the watchdog timer.

Description:

This function sets the value to load into the watchdog timer when the count reaches zero for the first time; if the watchdog timer is running when this function is called, then the value will be immediately loaded into the watchdog timer counter. If the parameter ulLoadVal is 0, then an interrupt is immediately generated.

Note:


See also:

WatchdogLock() ,

WatchdogUnlock() ,

WatchdogReloadGet()

Returns:

None.

18.2.2.11 WatchdogResetDisable

Disables the watchdog timer reset.

Prototype:

void

WatchdogResetDisable(unsigned long ulBase)

Parameters:


Description:

Disables the capability of the watchdog timer to issue a reset to the processor upon a second timeout condition.

Note:


See also:

WatchdogLock() ,

WatchdogUnlock()

234 October 11, 2007


Returns:

None.

18.2.2.12 WatchdogResetEnable

Enables the watchdog timer reset.

Prototype:

void

WatchdogResetEnable(unsigned long ulBase)

Parameters:


Description:

Enables the capability of the watchdog timer to issue a reset to the processor upon a second timeout condition.

Note:


See also:

WatchdogLock() ,

WatchdogUnlock()

Returns:

None.

18.2.2.13 WatchdogRunning

Determines if the watchdog timer is enabled.

Prototype:

tBoolean

WatchdogRunning(unsigned long ulBase)

Parameters:


Description:

This will check to see if the watchdog timer is enabled.

Returns:

Returns true if the watchdog timer is enabled, and false if it is not.

18.2.2.14 WatchdogStallDisable

Disables stalling of the watchdog timer during debug events.

Prototype:

void

WatchdogStallDisable(unsigned long ulBase)

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Watchdog Timer

Parameters:


Description:

This function disables the debug mode stall of the watchdog timer. By doing so, the watchdog timer continues to count regardless of the processor debug state.

Returns:

None.

18.2.2.15 WatchdogStallEnable

Enables stalling of the watchdog timer during debug events.

Prototype:

void

WatchdogStallEnable(unsigned long ulBase)

Parameters:


Description:

This function allows the watchdog timer to stop counting when the processor is stopped by the debugger. By doing so, the watchdog is prevented from expiring (typically almost immediately from a human time perspective) and resetting the system (if reset is enabled). The watchdog will instead expired after the appropriate number of processor cycles have been executed while debugging (or at the appropriate time after the processor has been restarted).

Returns:

None.

18.2.2.16 WatchdogUnlock

Disables the watchdog timer lock mechanism.

Prototype:

void

WatchdogUnlock(unsigned long ulBase)

Parameters:


Description:

Enables write access to the watchdog timer configuration registers.

Returns:

None.

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18.2.2.17 WatchdogValueGet

Gets the current watchdog timer value.

Prototype:

unsigned long

WatchdogValueGet(unsigned long ulBase)

Parameters:


Description:

This function reads the current value of the watchdog timer.

Returns:

Returns the current value of the watchdog timer.

18.3


The following example shows how to set up the watchdog timer API to reset the processor after two timeouts.

//

// Check to see if the registers are locked, and if so, unlock them.

// if(WatchdogLockState(WATCHDOG_BASE) == true)

{

WatchdogUnlock(WATCHDOG_BASE);

}

//

// Initialize the watchdog timer.

//

WatchdogReloadSet(WATCHDOG_BASE, 0xFEEFEE);

//

// Enable the reset.

//

WatchdogResetEnable(WATCHDOG_BASE);

//

// Enable the watchdog timer.

//

WatchdogEnable(WATCHDOG_BASE);

//

// Wait for the reset to occur.

// while(1)

{

}

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Watchdog Timer

238 October 11, 2007


19 Error Handling

Invalid arguments and error conditions are handled in a non-traditional manner in the peripheral driver library. Typically, a function would check its arguments to make sure that they are valid (if required; some may be unconditionally valid such as a 32-bit value used as the load value for a

32-bit timer). If an invalid argument is provided, it would return an error code. The caller then has to check the return code from each invocation of the function to make sure that it succeeded.

This results in a sizable amount of argument checking code in each function and return code checking code at each call site. For a self-contained application, this extra code becomes an unneeded burden once the application is debugged. Having a means of removing it allows the final code to be smaller and therefore run faster.

In the peripheral driver library, most functions do not return errors ( FlashProgram() ,

FlashErase() ,

FlashProtectSet() , and FlashProtectSave()

are the notable exceptions). Argument checking is done via a call to the ASSERT macro (provided in debug.h). This macro has the usual definition of an assert macro; it takes an expression that “must” be true. By making this macro be empty, the argument checking is removed from the code.

There are two definitions of the ASSERT macro provided in debug.h; one that is empty (used for normal situations) and one that evaluates the expression (used when the library is built with debugging). The debug version will call the __error__ function whenever the expression is not true, passing the file name and line number of the ASSERT macro invocation. The __error__ function is prototyped in debug.h and must be provided by the application since it is the application’s responsibility to deal with error conditions.

By setting a breakpoint on the __error__ function, the debugger will immediately stop whenever an error occurs anywhere in the application (something that would be very difficult to do with other error checking methods). When the debugger stops, the arguments to the __error_ function and the backtrace of the stack will pinpoint the function that found an error, what it found to be a problem, and where it was called from. As an example: void

SSIConfig(unsigned long ulBase, unsigned long ulProtocol, unsigned long ulMode, unsigned long ulBitRate, unsigned long ulDataWidth)

{

//

// Check the arguments.

//

ASSERT(ulBase == SSI_BASE);

ASSERT((ulProtocol == SSI_FRF_MOTO_MODE_0) ||

(ulProtocol == SSI_FRF_MOTO_MODE_1) ||



(ulProtocol == SSI_FRF_TI) ||

(ulProtocol == SSI_FRF_NMW));

ASSERT((ulMode == SSI_MODE_MASTER) ||

(ulMode == SSI_MODE_SLAVE) ||

(ulMode == SSI_MODE_SLAVE_OD));

ASSERT((ulDataWidth >= 4) && (ulDataWidth <= 16));

Each argument is individually checked, so the line number of the failing ASSERT will indicate the argument that is invalid. The debugger will be able to display the values of the arguments (from the stack backtrace) as well as the caller of the function that had the argument error. This allows the problem to be quickly identified at the cost of a small amount of code.

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240 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246

20.1

Introduction

The DK-LM3S101 example applications show how to utilize features of the Cortex-M3 microprocessor, the peripherals on the Stellaris microcontroller, and the drivers provided by the peripheral driver library. These applications are intended for demonstration and as a starting point for new applications.

There is a board specific driver for the Peripheral Device Controller on the Stellaris Family Development Kit board. The PDC is used to access the character LCD, eight user LEDs, eight user DIP switches, and twenty-four GPIOs.

20.2

API Functions

Functions unsigned char

PDCDIPRead

(void) unsigned char

PDCGPIODirRead

(unsigned char ucIdx) void

PDCGPIODirWrite

(unsigned char ucIdx, unsigned char ucValue) unsigned char

PDCGPIORead


PDCGPIOWrite

(unsigned char ucIdx, unsigned char ucValue) void

PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar

(unsigned char ucChar, unsigned char ∗pucData) void

PDCLCDInit

(void) void

PDCLCDSetPos

(unsigned char ucX, unsigned char ucY) void

PDCLCDWrite

(const char ∗pcStr, unsigned long ulCount) unsigned char

PDCLEDRead

(void) void

PDCLEDWrite

(unsigned char ucLED) unsigned char

PDCRead

(unsigned char ucAddr) void

PDCWrite

(unsigned char ucAddr, unsigned char ucData)

20.2.1


Each API specifies the source file that contains it and the header file that provides the prototype for application use.

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DK-LM3S101 Example Applications

20.2.2


20.2.2.1 PDCDIPRead

Read the current value of the PDC DIP switches.

Prototype:

unsigned char

PDCDIPRead(void)

Description:

This function will read the current value of the DIP switches attached to the PDC on the Stellaris development board.

Returns:

The current state of the DIP switches.

20.2.2.2 PDCGPIODirRead

Reads a GPIO direction register.

Prototype:

unsigned char

PDCGPIODirRead(unsigned char ucIdx)

Parameters:

ucIdx is the index of the GPIO direction register to read; valid values are 0, 1, and 2.

Description:

This function reads one of the GPIO direction registers in the PDC. The direction bit is set for pins that are outputs and clear for pins that are inputs.

Returns:

The contents of the direction register.

20.2.2.3 PDCGPIODirWrite

Write a GPIO direction register.

Prototype:

void

PDCGPIODirWrite(unsigned char ucIdx, unsigned char ucValue)

Parameters:

ucIdx is the index of the GPIO direction register to write; valid values are 0, 1, and 2.

ucValue is the value to write to the GPIO direction register.

Description:

This function writes ones of the GPIO direction registers in the PDC. The direction bit should be set for pins that are to be outputs and clear for pins that are to be inputs.

242 October 11, 2007


Returns:

None.

20.2.2.4 PDCGPIORead

Reads a GPIO data register.

Prototype:

unsigned char

PDCGPIORead(unsigned char ucIdx)

Parameters:


Description:

This function reads one of the GPIO data registers in the PDC. The value returned for a pin is the value being driven out for outputs or the value being read for inputs.

Returns:

The contents of the data register.

20.2.2.5 PDCGPIOWrite

Write a GPIO data register.

Prototype:

void

PDCGPIOWrite(unsigned char ucIdx, unsigned char ucValue)

Parameters:

ucIdx is the index of the GPIO data register to write; valid values are 0, 1, and 2.

ucValue is the value to write to the GPIO data register.

Description:

This function writes one of the GPIO direction registers in the PDC. The written to a pin is driven out for output pins and ignored for input pins.

Returns:

None.

20.2.2.6 PDCInit

Initializes the connection to the PDC.

Prototype:

void

PDCInit(void)

October 11, 2007 243


Description:

This function will enable clocking to the SSI and GPIO A modules, configure the GPIO pins to be used for an SSI interface, and it will configure the SSI as a 1 Mbps master device, operating in MOTO mode. It will also enable the SSI module, and will enable the chip select for the PDC on the Stellaris development board.

Returns:

None.

20.2.2.7 PDCLCDBacklightOff

Turn off the backlight.

Prototype:

void

PDCLCDBacklightOff(void)

Description:

This function turns off the backlight on the LCD.

Returns:

None.

20.2.2.8 PDCLCDBacklightOn

Turns on the backlight.

Prototype:

void

PDCLCDBacklightOn(void)

Description:

This function turns on the backlight on the LCD.

Returns:

None.

20.2.2.9 PDCLCDClear

Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:

This function clears the contents of the LCD screen. The cursor will be returned to the upper left corner.

Returns:

None.

244 October 11, 2007


20.2.2.10 PDCLCDCreateChar

Write a character pattern to the LCD.

Prototype:

void

PDCLCDCreateChar(unsigned char ucChar, unsigned char *pucData)

Parameters:

ucChar is the character index to create. Valid values are zero through seven.

pucData is the data for the character pattern. It contains eight bytes, with the first byte being the top row of the pattern. In each byte, the LSB is the right pixel of the pattern.

Description:

This function will write a character pattern into the LCD for use as a character to be displayed.

After writing the pattern, it can be used on the LCD by writing the corresponding character index to the display.

Returns:

None.

20.2.2.11 PDCLCDInit

Initializes the LCD display.

Prototype:

void

PDCLCDInit(void)

Description:

This function will set up the LCD display for writing. It will set the data bus to 8 bits, set the number of lines to 2, and the font size to 5x10. It will also turn the display off, clear the display, turn the display back on, and enable the backlight.

Note:

The PDC must be initialized via the

PDCInit()

function before this function can be called. Also, it may be necessary to adjust the contrast potentiometer in order to discern any output on the

LCD display.

Returns:

None.

20.2.2.12 PDCLCDSetPos

Set the position of the cursor.

Prototype:

void

PDCLCDSetPos(unsigned char ucX, unsigned char ucY)

October 11, 2007 245


Parameters:

ucX is the horizontal position. Valid values are zero through fifteen.

ucY is the vertical position.. Valid values are zero and one.

Description:

This function will move the cursor to the specified position. All characters written to the LCD are placed at the current cursor position, which is automatically advanced.

Returns:

None.

20.2.2.13 PDCLCDWrite

Writes a string to the LCD display.

Prototype:

void

PDCLCDWrite(const char *pcStr, unsigned long ulCount)

Parameters:

pcStr pointer to the string to be displayed.

ulCount is the number of characters to be displayed.

Description:

This function will display a string on the LCD at the current cursor position. It is the caller’s responsibility to position the cursor to the place where the string should be displayed (either explicitly via

PDCLCDSetPos()

or implicitly from where the cursor was left after a previous call to

PDCLCDWrite() ), and to properly account for the LCD boundary (line wrapping is not

automatically performed). Null characters are not treated special and are written to the LCD, which interprets it as a special programmable character glyph (see

PDCLCDCreateChar() ).

Returns:

None.

20.2.2.14 PDCLEDRead

Read the current status of the PDC LEDs.

Prototype:

unsigned char

PDCLEDRead(void)

Description:

This function will read the state of the LEDs connected to the PDC on the Stellaris development board.

Returns:

The value currently displayed by the LEDs.

246 October 11, 2007


20.2.2.15 PDCLEDWrite

Write to the PDC LEDs.

Prototype:

void

PDCLEDWrite(unsigned char ucLED)

Parameters:

ucLED value to write to the LEDs.

Description:

This function set the state of the LEDs connected to the PDC on the Stellaris development board.

Returns:

None.

20.2.2.16 PDCRead

Read a PDC register.

Prototype:

unsigned char

PDCRead(unsigned char ucAddr)

Parameters:

ucAddr specifies the PDC register to read.

Description:

This function will perform the SSI transfers required to read a register in the PDC on the Stellaris development board.

Returns:

Returns the value read from the PDC.

20.2.2.17 PDCWrite

Write a PDC register.

Prototype:

void

PDCWrite(unsigned char ucAddr, unsigned char ucData)

Parameters:

ucAddr specifies the PDC register to write.

ucData specifies the data to write.

Description:

This function will perform the SSI transfers required to write a register in the PDC on the

Stellaris development board.

October 11, 2007 247


Returns:

None.

20.3

Examples

Bit-Banding (bitband)

This example application demonstrates the use of the bit-banding capabilities of the Cortex-M3 microprocessor. All of SRAM and all of the peripherals reside within bit-band regions, meaning that bit-banding operations can be applied to any of them. In this example, a variable in SRAM is set to a particular value one bit at a time using bit-banding operations (it would be more efficient to do a single non-bit-banded write; this simply demonstrates the operation of bit-banding).

Blinky (blinky)

A very simple example that blinks the on-board LED.

248

Comparator (comparator)

This example application demonstrates the operation of the analog comparator(s). Comparator zero (which is present on all devices that have analog comparators) is configured to compare its negative input to an internally generated 1.65 V reference and toggle the state of the LED on port

B0 based on comparator change interrupts. The LED will be turned on by the interrupt handler when a rising edge on the comparator output is detected, and will be turned off when a falling edge is detected.

In order for this example to work properly, the ULED0 (JP22) jumper must be installed on the board.

GPIO JTAG Recovery (gpio_jtag)

This example demonstrates changing the JTAG pins into GPIOs, along with a mechanism to revert them to JTAG pins. When first run, the pins remain in JTAG mode. Pressing the user push button will toggle the pins between JTAG mode and GPIO mode. Because there is no debouncing of the push button (either in hardware or software), a button press will occasionally result in more than one mode change.

In this example, all five pins (PB7, PC0, PC1, PC2, and PC3) are switched, though the more typical use would be to change PB7 into a GPIO. Note that because of errata in Rev Bx and Rev C0 of

Sandstorm-class Stellaris microcontrollers, JTAG and SWD will not function if PB7 is configured as a GPIO. This errata is fixed in Rev C2 of Sandstorm-class Stellaris microcontrollers.

GPIO (gpio_led)

This example application uses LEDs connected to GPIO pins to create a "roving eye" display. Port

B0-B3 are driven in a sequential manner to give the illusion of an eye looking back and forth.

October 11, 2007


In order for this example to work properly, the ULED0 (JP22), ULED1 (JP23), ULED2 (JP24), and ULED3 (JP25) jumpers must be installed on the board, and the PB1 (JP1) jumper on the daughtercard must be set to pins 2 & 3.

Hello World (hello)

A very simple "hello world" example. It simply displays "hello world" on the LCD and is a starting point for more complicated applications.

Interrupts (interrupts)

This example application demonstrates the interrupt preemption and tail-chaining capabilities of

Cortex-M3 microprocessor and NVIC. Nested interrupts are synthesized when the interrupts have the same priority, increasing priorities, and decreasing priorities. With increasing priorities, preemption will occur; in the other two cases tail-chaining will occur. The currently pending interrupts and the currently executing interrupt will be displayed on the LCD; individual LEDs connected to port

B0-B2 will be turned on upon interrupt handler entry and off before interrupt handler exit so that the off-to-on time can be observed with a scope or logic analyzer to see the speed of tail-chaining (for the two cases where tail-chaining is occurring).

In order for this example to work properly, the ULED0 (JP22), ULED1 (JP23), and ULED2 (JP24) jumpers must be installed on the board, and the PB1 (JP1) jumper on the daughtercard must be set to pins 2 & 3.

DK-LM3S101 Quickstart Application (qs_dk-lm3s101)

This example uses the photocell on the development board to create a geiger counter for visible light. In bright light, the click rate (i.e. the count) increases; in low light it decreases. The light reading is also displayed on the LCD, and a log of the readings is output on the UART at 115,200,

8-n-1. The push button can be used to turn off the clicking noise on and off; when off the LCD and

UART still provide the light reading.

In the default jumper configuration of the development board, this example actually samples the potentiometer and the push button will not work. In order for this example to fully work, the following jumper wire connections must be made: JP3 pin 1 to JP5 pin 2 (requiring the removal of the jumper on JP5) and JP19 pin 2 to J6 pin 6.

SSI (ssi_atmel)

This example application uses the SSI master to communicate with the Atmel AT25F1024A EEP-

ROM that is on the development board. The first 256 bytes of the EEPROM are erased and then programmed with an incrementing sequence. The data is then read back to verify its correctness.

The transfer is managed by an interrupt handler in response to the SSI interrupt; since a 256-byte read at a 1 MHz SSI bus speed takes around 2 ms, this allows a lot of other processing to occur during the transfer (though that time is not utilized by this example).

October 11, 2007 249


Timer (timers)

This example application demonstrates the use of the timers to generate periodic interrupts. One timer is set up to interrupt once per second and the other to interrupt twice per second; each interrupt handler will toggle its own GPIO (port B0 and B1) on each interrupt; the attached LED will indicate the occurrence and rate of interrupts.

UART (uart_echo)

This example application utilizes the UART to echo text. The first UART (the SER0 connector on the

Stellaris Family Development Board) will be configured in 115,200 baud, 8-n-1 mode. All characters received on the UART are transmitted back to the UART.

Watchdog (watchdog)

This example application demonstrates the use of the watchdog as a simple heartbeat for the system. If the watchdog is not periodically fed, it will reset the system. Each time the watchdog is fed, the LED connected to port B0 is inverted so that it is easy to see that it is being fed, which occurs once every second.

250 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256

21.1

Introduction



21.2

API Functions


PDCDIPRead


PDCGPIODirRead


PDCGPIODirWrite


PDCGPIORead


PDCGPIOWrite


PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar


PDCLCDInit

(void) void

PDCLCDSetPos


PDCLCDWrite


PDCLEDRead

(void) void

PDCLEDWrite


PDCRead


PDCWrite


21.2.1



October 11, 2007 251


21.2.2


21.2.2.1 PDCDIPRead


Prototype:

unsigned char

PDCDIPRead(void)

Description:


Returns:




Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


252 October 11, 2007


Returns:

None.



Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


Returns:

None.

21.2.2.6 PDCInit


Prototype:

void

PDCInit(void)

October 11, 2007 253


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.


Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:


Returns:

None.

254 October 11, 2007




Prototype:

void


Parameters:



Description:



Returns:

None.



Prototype:

void

PDCLCDInit(void)

Description:


Note:


PDCInit()


LCD display.

Returns:

None.



Prototype:

void


October 11, 2007 255


Parameters:



Description:


Returns:

None.



Prototype:

void


Parameters:



Description:


PDCLCDSetPos()





Returns:

None.



Prototype:

unsigned char

PDCLEDRead(void)

Description:


Returns:


256 October 11, 2007




Prototype:

void


Parameters:


Description:


Returns:

None.

21.2.2.16 PDCRead


Prototype:

unsigned char


Parameters:


Description:


Returns:


21.2.2.17 PDCWrite


Prototype:

void


Parameters:



Description:



October 11, 2007 257


Returns:

None.

21.3

Examples



Blinky (blinky)


258









GPIO (gpio_led)



October 11, 2007



Hello World (hello)


I2C (i2c_atmel)

This example application uses the I2C master to communicate with the Atmel AT24C08A EEPROM that is on the development board. The first sixteen bytes of the EEPROM are erased and then programmed with an incrementing sequence. The data is then read back to verify its correctness.

The transfer is managed by an interrupt handler in response to the I2C interrupt; since a sixteenbyte read at a 100 kHz I2C bus speed takes almost 2 ms, this allows a lot of other processing to occur during the transfer (though that time is not utilized by this example).

In order for this example to work properly, the I2C_SCL (JP14), I2C_SDA (JP13), and I2CM_A2

(JP11) jumpers must be installed on the board, and the I2CM_WP (JP12) jumper must be removed.











October 11, 2007 259


SSI (ssi_atmel)




Timer (timers)


UART (uart_echo)



Watchdog (watchdog)


260 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

22.1

Introduction



22.2

API Functions


PDCDIPRead


PDCGPIODirRead


PDCGPIODirWrite


PDCGPIORead


PDCGPIOWrite


PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar


PDCLCDInit

(void) void

PDCLCDSetPos


PDCLCDWrite


PDCLEDRead

(void) void

PDCLEDWrite


PDCRead


PDCWrite


22.2.1



October 11, 2007 261


22.2.2


22.2.2.1 PDCDIPRead


Prototype:

unsigned char

PDCDIPRead(void)

Description:


Returns:




Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


262 October 11, 2007


Returns:

None.



Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


Returns:

None.

22.2.2.6 PDCInit


Prototype:

void

PDCInit(void)

October 11, 2007 263


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.


Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:


Returns:

None.

264 October 11, 2007




Prototype:

void


Parameters:



Description:



Returns:

None.



Prototype:

void

PDCLCDInit(void)

Description:


Note:


PDCInit()


LCD display.

Returns:

None.



Prototype:

void


October 11, 2007 265


Parameters:



Description:


Returns:

None.



Prototype:

void


Parameters:



Description:


PDCLCDSetPos()





Returns:

None.



Prototype:

unsigned char

PDCLEDRead(void)

Description:


Returns:


266 October 11, 2007




Prototype:

void


Parameters:


Description:


Returns:

None.

22.2.2.16 PDCRead


Prototype:

unsigned char


Parameters:


Description:


Returns:


22.2.2.17 PDCWrite


Prototype:

void


Parameters:



Description:



October 11, 2007 267


Returns:

None.

22.3

Examples



Blinky (blinky)


268









GPIO (gpio_led)



October 11, 2007



Hello World (hello)







PWM (pwmgen)

This example application utilizes the PWM peripheral to output a 25% duty cycle PWM signal and a 75% duty cycle PWM signal, both at 50 kHz. Once configured, the application enters an infinite loop, doing nothing while the PWM peripheral continues to output its signals.






October 11, 2007 269


SSI (ssi_atmel)




Timer (timers)


UART (uart_echo)



Watchdog (watchdog)


270 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

23.1

Introduction



23.2

API Functions


PDCDIPRead


PDCGPIODirRead


PDCGPIODirWrite


PDCGPIORead


PDCGPIOWrite


PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar


PDCLCDInit

(void) void

PDCLCDSetPos


PDCLCDWrite


PDCLEDRead

(void) void

PDCLEDWrite


PDCRead


PDCWrite


23.2.1



October 11, 2007 271


23.2.2


23.2.2.1 PDCDIPRead


Prototype:

unsigned char

PDCDIPRead(void)

Description:


Returns:




Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


272 October 11, 2007


Returns:

None.



Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


Returns:

None.

23.2.2.6 PDCInit


Prototype:

void

PDCInit(void)

October 11, 2007 273


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.


Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:


Returns:

None.

274 October 11, 2007




Prototype:

void


Parameters:



Description:



Returns:

None.



Prototype:

void

PDCLCDInit(void)

Description:


Note:


PDCInit()


LCD display.

Returns:

None.



Prototype:

void


October 11, 2007 275


Parameters:



Description:


Returns:

None.



Prototype:

void


Parameters:



Description:


PDCLCDSetPos()





Returns:

None.



Prototype:

unsigned char

PDCLEDRead(void)

Description:


Returns:


276 October 11, 2007




Prototype:

void


Parameters:


Description:


Returns:

None.

23.2.2.16 PDCRead


Prototype:

unsigned char


Parameters:


Description:


Returns:


23.2.2.17 PDCWrite


Prototype:

void


Parameters:



Description:



October 11, 2007 277


Returns:

None.

23.3

Examples



Blinky (blinky)


278









GPIO (gpio_led)



October 11, 2007



Hello World (hello)


I2C (i2c_atmel)










PWM (pwmgen)



This example uses the potentiometer on the development board to vary the rate and frequency of a repetitive beep from the piezo buzzer. Turning the knob in one direction will result in slower

October 11, 2007 279

DK-LM3S801 Example Applications beeps at lower frequency, while turning it the other direction will result in faster beeps at a higher frequency. The potentiometer setting along with the tone "note" is displayed on the LCD, and a log of the readings is output on the UART at 115,200, 8-n-1. The push button can be used to turn the beeping noise on and off; when off the LCD and UART still show the setting.

SSI (ssi_atmel)




Timer (timers)


UART (uart_echo)



Watchdog (watchdog)


280 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286

24.1

Introduction



24.2

API Functions


PDCDIPRead


PDCGPIODirRead


PDCGPIODirWrite


PDCGPIORead


PDCGPIOWrite


PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar


PDCLCDInit

(void) void

PDCLCDSetPos


PDCLCDWrite


PDCLEDRead

(void) void

PDCLEDWrite


PDCRead


PDCWrite


24.2.1



October 11, 2007 281


24.2.2


24.2.2.1 PDCDIPRead


Prototype:

unsigned char

PDCDIPRead(void)

Description:


Returns:




Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


282 October 11, 2007


Returns:

None.



Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


Returns:

None.

24.2.2.6 PDCInit


Prototype:

void

PDCInit(void)

October 11, 2007 283


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.


Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:


Returns:

None.

284 October 11, 2007




Prototype:

void


Parameters:



Description:



Returns:

None.



Prototype:

void

PDCLCDInit(void)

Description:


Note:


PDCInit()


LCD display.

Returns:

None.



Prototype:

void


October 11, 2007 285


Parameters:



Description:


Returns:

None.



Prototype:

void


Parameters:



Description:


PDCLCDSetPos()





Returns:

None.



Prototype:

unsigned char

PDCLEDRead(void)

Description:


Returns:


286 October 11, 2007




Prototype:

void


Parameters:


Description:


Returns:

None.

24.2.2.16 PDCRead


Prototype:

unsigned char


Parameters:


Description:


Returns:


24.2.2.17 PDCWrite


Prototype:

void


Parameters:



Description:



October 11, 2007 287


Returns:

None.

24.3

Examples



Blinky (blinky)


288









GPIO (gpio_led)



October 11, 2007



Hello World (hello)


I2C (i2c_atmel)










PWM (pwmgen)



This example uses the potentiometer on the development board to vary the rate of a repetitive beep from the piezo buzzer, while the light sensor will vary the frequency of the beep. Turning the knob

October 11, 2007 289

DK-LM3S811 Example Applications in one direction will result in slower beeps while turning it in the other direction will result in faster beeps. The amount of light falling on the light sensor affects the frequency of the beep. The more light falling on the sensor the higher the pitch of the beep. The potentiometer setting along with the "note" representing the pitch of the beep is displayed on the LCD, and a log of the readings is output on the UART at 115,200, 8-n-1. The push button can be used to turn the beeping noise on and off; when off the LCD and UART still provide the settings.

In the default jumper configuration of the development board, the push button will not actually mute the beep. In order for this example to fully work, the following jumper wire connections must be made: JP19 pin 2 to J6 pin 6.

SSI (ssi_atmel)




Timer (timers)


UART (uart_echo)



Watchdog (watchdog)


290 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

25.1

Introduction



25.2

API Functions


PDCDIPRead


PDCGPIODirRead


PDCGPIODirWrite


PDCGPIORead


PDCGPIOWrite


PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar


PDCLCDInit

(void) void

PDCLCDSetPos


PDCLCDWrite


PDCLEDRead

(void) void

PDCLEDWrite


PDCRead


PDCWrite


25.2.1



October 11, 2007 291


25.2.2


25.2.2.1 PDCDIPRead


Prototype:

unsigned char

PDCDIPRead(void)

Description:


Returns:




Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


292 October 11, 2007


Returns:

None.



Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


Returns:

None.

25.2.2.6 PDCInit


Prototype:

void

PDCInit(void)

October 11, 2007 293


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.


Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:


Returns:

None.

294 October 11, 2007




Prototype:

void


Parameters:



Description:



Returns:

None.



Prototype:

void

PDCLCDInit(void)

Description:


Note:


PDCInit()


LCD display.

Returns:

None.



Prototype:

void


October 11, 2007 295


Parameters:



Description:


Returns:

None.



Prototype:

void


Parameters:



Description:


PDCLCDSetPos()





Returns:

None.



Prototype:

unsigned char

PDCLEDRead(void)

Description:


Returns:


296 October 11, 2007




Prototype:

void


Parameters:


Description:


Returns:

None.

25.2.2.16 PDCRead


Prototype:

unsigned char


Parameters:


Description:


Returns:


25.2.2.17 PDCWrite


Prototype:

void


Parameters:



Description:



October 11, 2007 297


Returns:

None.

25.3

Examples



Blinky (blinky)


298









GPIO (gpio_led)



October 11, 2007



Hello World (hello)


I2C (i2c_atmel)










PWM (pwmgen)



This example uses the potentiometer on the development board to vary the rate of a repetitive beep from the piezo buzzer, while the light sensor will vary the frequency of the beep. Turning the knob

October 11, 2007 299

DK-LM3S815 Example Applications in one direction will result in slower beeps while turning it in the other direction will result in faster beeps. The amount of light falling on the light sensor affects the frequency of the beep. The more light falling on the sensor the higher the pitch of the beep. The potentiometer setting along with the "note" representing the pitch of the beep is displayed on the LCD, and a log of the readings is output on the UART at 115,200, 8-n-1. The push button can be used to turn the beeping noise on and off; when off the LCD and UART still provide the settings.


SSI (ssi_atmel)




Timer (timers)


UART (uart_echo)



Watchdog (watchdog)


300 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306

26.1

Introduction



26.2

API Functions


PDCDIPRead


PDCGPIODirRead


PDCGPIODirWrite


PDCGPIORead


PDCGPIOWrite


PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar


PDCLCDInit

(void) void

PDCLCDSetPos


PDCLCDWrite


PDCLEDRead

(void) void

PDCLEDWrite


PDCRead


PDCWrite


26.2.1



October 11, 2007 301


26.2.2


26.2.2.1 PDCDIPRead


Prototype:

unsigned char

PDCDIPRead(void)

Description:


Returns:




Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


302 October 11, 2007


Returns:

None.



Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


Returns:

None.

26.2.2.6 PDCInit


Prototype:

void

PDCInit(void)

October 11, 2007 303


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.


Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:


Returns:

None.

304 October 11, 2007




Prototype:

void


Parameters:



Description:



Returns:

None.



Prototype:

void

PDCLCDInit(void)

Description:


Note:


PDCInit()


LCD display.

Returns:

None.



Prototype:

void


October 11, 2007 305


Parameters:



Description:


Returns:

None.



Prototype:

void


Parameters:



Description:


PDCLCDSetPos()





Returns:

None.



Prototype:

unsigned char

PDCLEDRead(void)

Description:


Returns:


306 October 11, 2007




Prototype:

void


Parameters:


Description:


Returns:

None.

26.2.2.16 PDCRead


Prototype:

unsigned char


Parameters:


Description:


Returns:


26.2.2.17 PDCWrite


Prototype:

void


Parameters:



Description:



October 11, 2007 307


Returns:

None.

26.3

Examples



Blinky (blinky)


308









GPIO (gpio_led)



October 11, 2007



Hello World (hello)







PWM (pwmgen)



This example uses the potentiometer on the development board to vary the rate of a repetitive beep from the piezo buzzer, while the light sensor will vary the frequency of the beep. Turning the knob in one direction will result in slower beeps while turning it in the other direction will result in faster beeps. The amount of light falling on the light sensor affects the frequency of the beep. The more light falling on the sensor the higher the pitch of the beep. The potentiometer setting along with the "note" representing the pitch of the beep is displayed on the LCD, and a log of the readings is output on the UART at 115,200, 8-n-1. The push button can be used to turn the beeping noise on and off; when off the LCD and UART still provide the settings.


October 11, 2007 309


SSI (ssi_atmel)




Timer (timers)


UART (uart_echo)



Watchdog (watchdog)


310 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316

27.1

Introduction



27.2

API Functions


PDCDIPRead


PDCGPIODirRead


PDCGPIODirWrite


PDCGPIORead


PDCGPIOWrite


PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar


PDCLCDInit

(void) void

PDCLCDSetPos


PDCLCDWrite


PDCLEDRead

(void) void

PDCLEDWrite


PDCRead


PDCWrite


27.2.1



October 11, 2007 311


27.2.2


27.2.2.1 PDCDIPRead


Prototype:

unsigned char

PDCDIPRead(void)

Description:


Returns:




Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


312 October 11, 2007


Returns:

None.



Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


Returns:

None.

27.2.2.6 PDCInit


Prototype:

void

PDCInit(void)

October 11, 2007 313


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.


Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:


Returns:

None.

314 October 11, 2007




Prototype:

void


Parameters:



Description:



Returns:

None.



Prototype:

void

PDCLCDInit(void)

Description:


Note:


PDCInit()


LCD display.

Returns:

None.



Prototype:

void


October 11, 2007 315


Parameters:



Description:


Returns:

None.



Prototype:

void


Parameters:



Description:


PDCLCDSetPos()





Returns:

None.



Prototype:

unsigned char

PDCLEDRead(void)

Description:


Returns:


316 October 11, 2007




Prototype:

void


Parameters:


Description:


Returns:

None.

27.2.2.16 PDCRead


Prototype:

unsigned char


Parameters:


Description:


Returns:


27.2.2.17 PDCWrite


Prototype:

void


Parameters:



Description:



October 11, 2007 317


Returns:

None.

27.3

Examples



Blinky (blinky)


318









GPIO (gpio_led)



October 11, 2007



Hello World (hello)







PWM (pwmgen)



This example uses the potentiometer on the development board to vary the rate of a repetitive beep from the piezo buzzer, while the light sensor will vary the frequency of the beep. Turning the knob in one direction will result in slower beeps while turning it in the other direction will result in faster beeps. The amount of light falling on the light sensor affects the frequency of the beep. The more light falling on the sensor the higher the pitch of the beep. The potentiometer setting along with the "note" representing the pitch of the beep is displayed on the LCD, and a log of the readings is output on the UART at 115,200, 8-n-1. The push button can be used to turn the beeping noise on and off; when off the LCD and UART still provide the settings.


October 11, 2007 319


SSI (ssi_atmel)




Timer (timers)


UART (uart_echo)



Watchdog (watchdog)


320 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

28.1

Introduction



28.2

API Functions


PDCDIPRead


PDCGPIODirRead


PDCGPIODirWrite


PDCGPIORead


PDCGPIOWrite


PDCInit

(void) void

PDCLCDBacklightOff

(void) void

PDCLCDBacklightOn

(void) void

PDCLCDClear

(void) void

PDCLCDCreateChar


PDCLCDInit

(void) void

PDCLCDSetPos


PDCLCDWrite


PDCLEDRead

(void) void

PDCLEDWrite


PDCRead


PDCWrite


28.2.1



October 11, 2007 321


28.2.2


28.2.2.1 PDCDIPRead


Prototype:

unsigned char

PDCDIPRead(void)

Description:


Returns:




Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


322 October 11, 2007


Returns:

None.



Prototype:

unsigned char


Parameters:


Description:


Returns:




Prototype:

void


Parameters:



Description:


Returns:

None.

28.2.2.6 PDCInit


Prototype:

void

PDCInit(void)

October 11, 2007 323


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.


Clear the screen.

Prototype:

void

PDCLCDClear(void)

Description:


Returns:

None.

324 October 11, 2007




Prototype:

void


Parameters:



Description:



Returns:

None.



Prototype:

void

PDCLCDInit(void)

Description:


Note:


PDCInit()


LCD display.

Returns:

None.



Prototype:

void


October 11, 2007 325


Parameters:



Description:


Returns:

None.



Prototype:

void


Parameters:



Description:


PDCLCDSetPos()





Returns:

None.



Prototype:

unsigned char

PDCLEDRead(void)

Description:


Returns:


326 October 11, 2007




Prototype:

void


Parameters:


Description:


Returns:

None.

28.2.2.16 PDCRead


Prototype:

unsigned char


Parameters:


Description:


Returns:


28.2.2.17 PDCWrite


Prototype:

void


Parameters:



Description:



October 11, 2007 327


Returns:

None.

28.3

Examples



Blinky (blinky)






GPIO (gpio_led)




Hello World (hello)


328 October 11, 2007


I2C (i2c_atmel)











This example uses the potentiometer on the development board to vary the rate of a click sound from the piezo buzzer. Turning the knob in one direction will result in slower clicks while turning it in the other direction will result in faster clicks. The potentiometer setting is displayed on the LCD, and a log of the readings is output on the UART at 115,200, 8-n-1. The push button can be used to turn the clicking noise on and off; when off the LCD and UART still provide the settings.

SSI (ssi_atmel)




October 11, 2007 329


Timer (timers)


UART (uart_echo)



Watchdog (watchdog)


330 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337

29.1

Introduction

The EK-LM3S1968 example applications show how to utilize features of the Cortex-M3 microprocessor, the peripherals on the Stellaris microcontroller, and the drivers provided by the peripheral driver library. These applications are intended for demonstration and as a starting point for new applications.

There is a board specific driver for the RiTdisplay 128x96 4-bit gray-scale OLED graphical display on the Stellaris LM3S1968 Evaluation Kit board.

There is also a board specific driver for the Class-D audio amplifier and speaker on the board. In order to use this driver, the system clock should be as high as possible and must be at least 256

KHz; increasing the system clock rate result in higher quality audio. This driver will play both 8-bit

PCM data and 4-bit ADPCM data; the converter application (converter.c is the source code, and converter.exe is a pre-built binary) will take raw 16-bit signed PCM data and convert it into a C array that can be included in an application for playback purposes. For example, to encode voice.pcm

with ADPCM and produce a C array called g_pucVoice: converter -a -n g_pucVoice -o voice.h voice.pcm

To do the same, but encode to 8-bit PCM: converter -p -n g_pucVoice -o voice.h voice.pcm

Since the Class-D audio driver will only play 8 KHz mono streams, and the converter application will only handle raw PCM input, an application such as sox will be needed to convert arbitrary wave files to the required format. To convert voice.wav to the required format for converter: sox voice.wav -t raw -r 8000 -c 1 -s -w voice.pcm polyphase

The polyphase at the end selects a higher quality sample rate conversion algorithm. It may be helpful (and/or necessary) to also include vol {factor} before polyphase in order to increase the volume of the waveform. If sox complains of clipping, the volume needs to be reduced.

sox can be found at http://sox.sourceforge.net

. There are numerous other audio applications (both open source and commercial) that can be used instead of sox.

29.2

API Functions

Functions tBoolean

ClassDBusy

(void)

October 11, 2007 331

EK-LM3S1968 Example Applications void

ClassDInit

(unsigned long ulPWMClock) void

ClassDPlayADPCM

(const unsigned char ∗pucBuffer, unsigned long ulLength) void

ClassDPlayPCM

(const unsigned char ∗pucBuffer, unsigned long ulLength) void

ClassDPWMHandler

(void) void

ClassDStop

(void) void

ClassDVolumeDown

(unsigned long ulVolume) void

ClassDVolumeSet


ClassDVolumeUp


RIT128x96x4Clear

(void) void

RIT128x96x4Disable

(void) void

RIT128x96x4DisplayOff

(void) void

RIT128x96x4DisplayOn

(void) void

RIT128x96x4Enable

(unsigned long ulFrequency) void

RIT128x96x4ImageDraw

(const unsigned char ∗pucImage, unsigned long ulX, unsigned long ulY, unsigned long ulWidth, unsigned long ulHeight) void

RIT128x96x4Init


RIT128x96x4StringDraw

(const char ∗pcStr, unsigned long ulX, unsigned long ulY, unsigned char ucLevel)

29.2.1



29.2.2


29.2.2.1 ClassDBusy

Determines if the Class-D audio driver is busy.

Prototype:

tBoolean

ClassDBusy(void)

Description:

This function determines if the Class-D audio driver is busy, either performing the startup ramp for the speaker or playing a stream.

Returns:

Returns true if the Class-D audio driver is busy and false otherwise.

29.2.2.2 ClassDInit

Initializes the Class-D audio driver.

332 October 11, 2007


Prototype:

void

ClassDInit(unsigned long ulPWMClock)

Parameters:

ulPWMClock is the rate of the clock supplied to the PWM module.

Description:

This function intializes the Class-D audio driver, preparing it to output audio data to the speaker.

The startup ramp of the speaker is started but will not complete until after this function returns

(use

ClassDBusy()

to determine when it has completed).

The PWM module clock should be as high as possible; lower clock rates reduces the quality of the produced audio. For the best quality audio, the PWM module should be clocked at 50

MHz.

Note:

In order for the Class-D audio driver to function properly, the Class-D audio driver interrupt

handler ( ClassDPWMHandler() ) must be installed into the vector table for the PWM1 interrupt.

Returns:

None.

29.2.2.3 ClassDPlayADPCM

Plays a buffer of 8 KHz IMA ADPCM data.

Prototype:

void

ClassDPlayADPCM(const unsigned char *pucBuffer, unsigned long ulLength)

Parameters:

pucBuffer is a pointer to the buffer containing the IMA ADPCM encoded data.

ulLength is the number of bytes in the buffer.

Description:

This function starts playback of a stream of IMA ADPCM encoded data. The data is decoded as needed and therefore does not require a large buffer in SRAM. This provides a 2:1 compression ratio relative to raw 8-bit PCM with little to no loss in audio quality.

Returns:

None.

29.2.2.4 ClassDPlayPCM

Plays a buffer of 8 KHz, 8-bit, unsigned PCM data.

Prototype:

void

ClassDPlayPCM(const unsigned char *pucBuffer, unsigned long ulLength)

October 11, 2007 333

EK-LM3S1968 Example Applications

Parameters:

pucBuffer is a pointer to the buffer containing 8-bit, unsigned PCM data.

ulLength is the number of bytes in the buffer.

Description:

This function starts playback of a stream of 8-bit, unsigned PCM data. Since the data is unsigned, a value of 128 represents the mid-point of the speaker’s travel (i.e. corresponds to no DC offset).

Returns:

None.

29.2.2.5 ClassDPWMHandler

Handles the PWM1 interrupt.

Prototype:

void

ClassDPWMHandler(void)

Description:

This function responds to the PWM1 interrupt, updating the duty cycle of the output waveform in order to produce sound. It is the application’s responsibility to ensure that this function is called in response to the PWM1 interrupt, typically by installing it in the vector table as the handler for the PWM1 interrupt.

Returns:

None.

29.2.2.6 ClassDStop

Stops playback of the current audio stream.

Prototype:

void

ClassDStop(void)

Description:

This function immediately stops playback of the current audio stream. As a result, the output is changed directly to the mid-point, possibly resulting in a pop or click.

Returns:

None.

29.2.2.7 ClassDVolumeDown

Decreases the volume of the audio playback.

334 October 11, 2007


Prototype:

void

ClassDVolumeDown(unsigned long ulVolume)

Parameters:

ulVolume is the amount by which to decrease the volume of the audio playback, specified as a value between 0 (for no adjustment) and 256 maximum adjustment).

Description:

This function decreases the volume of the audio playback relative to the current volume.

Returns:

None.

29.2.2.8 ClassDVolumeSet

Sets the volume of the audio playback.

Prototype:

void

ClassDVolumeSet(unsigned long ulVolume)

Parameters:

ulVolume is the volume of the audio playback, specified as a value between 0 (for silence) and 256 (for full volume).

Description:

This function sets the volume of the audio playback. Setting the volume to 0 will mute the output, while setting the volume to 256 will play the audio stream without any volume adjustment

(i.e. full volume).

Returns:

None.

29.2.2.9 ClassDVolumeUp

Increases the volume of the audio playback.

Prototype:

void

ClassDVolumeUp(unsigned long ulVolume)

Parameters:

ulVolume is the amount by which to increase the volume of the audio playback, specified as a value between 0 (for no adjustment) and 256 maximum adjustment).

Description:

This function increases the volume of the audio playback relative to the current volume.

Returns:

None.

October 11, 2007 335


29.2.2.10 RIT128x96x4Clear

Clears the OLED display.

Prototype:

void

RIT128x96x4Clear(void)

Description:

This function will clear the display RAM. All pixels in the display will be turned off.

Returns:

None.

29.2.2.11 RIT128x96x4Disable

Enable the SSI component of the OLED display driver.

Prototype:

void

RIT128x96x4Disable(void)

Description:

This function initializes the SSI interface to the OLED display.

Returns:

None.

29.2.2.12 RIT128x96x4DisplayOff

Turns off the OLED display.

Prototype:

void

RIT128x96x4DisplayOff(void)

Description:

This function will turn off the OLED display. This will stop the scanning of the panel and turn off the on-chip DC-DC converter, preventing damage to the panel due to burn-in (it has similar characters to a CRT in this respect).

Returns:

None.

29.2.2.13 RIT128x96x4DisplayOn

Turns on the OLED display.

336 October 11, 2007


Prototype:

void

RIT128x96x4DisplayOn(void)

Description:

This function will turn on the OLED display, causing it to display the contents of its internal frame buffer.

Returns:

None.

29.2.2.14 RIT128x96x4Enable


Prototype:

void

RIT128x96x4Enable(unsigned long ulFrequency)

Parameters:

ulFrequency specifies the SSI Clock Frequency to be used.

Description:


Returns:

None.

29.2.2.15 RIT128x96x4ImageDraw

Displays an image on the OLED display.

Prototype:

void

RIT128x96x4ImageDraw(const unsigned char *pucImage, unsigned long ulX, unsigned long ulY, unsigned long ulWidth, unsigned long ulHeight)

Parameters:

pucImage is a pointer to the image data.

ulX is the horizontal position to display this image, specified in columns from the left edge of the display.

ulY is the vertical position to display this image, specified in rows from the top of the display.

ulWidth is the width of the image, specified in columns.

ulHeight is the height of the image, specified in rows.

October 11, 2007 337


Description:

This function will display a bitmap graphic on the display. Because of the format of the display RAM, the starting column (ulX ) and the number of columns (ulWidth) must be an integer multiple of two.

The image data is organized with the first row of image data appearing left to right, followed immediately by the second row of image data. Each byte contains the data for two columns in the current row, with the leftmost column being contained in bits 7:4 and the rightmost column being contained in bits 3:0.

For example, an image six columns wide and seven scan lines tall would be arranged as follows

(showing how the twenty one bytes of the image would appear on the display):

+-------------------+-------------------+-------------------+

| Byte 0 | Byte 1 | Byte 2 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 12 | Byte 13 | Byte 14 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 15 | Byte 16 | Byte 17 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 18 | Byte 19 | Byte 20 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

Returns:

None.

29.2.2.16 RIT128x96x4Init

Initialize the OLED display.

Prototype:

void

RIT128x96x4Init(unsigned long ulFrequency)

Parameters:


Description:

This function initializes the SSI interface to the OLED display and configures the SSD1329 controller on the panel.

338 October 11, 2007


Returns:

None.

29.2.2.17 RIT128x96x4StringDraw

Displays a string on the OLED display.

Prototype:

void

RIT128x96x4StringDraw(const char *pcStr, unsigned long ulX, unsigned long ulY, unsigned char ucLevel)

Parameters:

pcStr is a pointer to the string to display.

ulX is the horizontal position to display the string, specified in columns from the left edge of the display.

ulY is the vertical position to display the string, specified in rows from the top edge of the display.

ucLevel is the 4-bit grey scale value to be used for displayed text.

Description:

This function will draw a string on the display. Only the ASCII characters between 32 (space) and 126 (tilde) are supported; other characters will result in random data being draw on the display (based on whatever appears before/after the font in memory). The font is mono-spaced, so characters such as "i" and "l" have more white space around them than characters such as

"m" or "w".

If the drawing of the string reaches the right edge of the display, no more characters will be drawn. Therefore, special care is not required to avoid supplying a string that is "too long" to display.

Note:

Because the OLED display packs 2 pixels of data in a single byte, the parameter ulX must be an even column number (e.g. 0, 2, 4, etc).

Returns:

None.

29.3

Examples

Audio Playback (audio)

This example application plays audio via the Class-D amplifier and speaker. The audio is provided in both PCM and ADPCM format so that the audio quality can be compared.

October 11, 2007 339




Blinky (blinky)



This example demonstrates changing the JTAG pins into GPIOs, along with a mechanism to revert them to JTAG pins. When first run, the pins remain in JTAG mode. Pressing the select push button will toggle the pins between JTAG mode and GPIO mode. Because there is no debouncing of the push button (either in hardware or software), a button press will occasionally result in more than one mode change.

In this example, all five pins (PB7, PC0, PC1, PC2, and PC3) are switched, though the more typical use would be to change PB7 into a GPIO.

Graphics Example (graphics)

A simple application that displays scrolling text on the top line of the OLED display, along with a

4-bit gray scale image.

Hello World (hello)

A very simple "hello world" example. It simply displays "hello world" on the OLED and is a starting point for more complicated applications.

Hibernate Example (hibernate)

An example to demonstrate the use of the hibernation module. The user can put the microcontroller in hibernation by pressing the select button. The microcontroller will then wake on its own after 5 seconds, or immediately if the user presses the select button again. The program keeps a count of the number of times it has entered hibernation. The value of the counter is stored in the battery backed memory of the hibernation module so that it can be retrieved when the microcontroller wakes.

340 October 11, 2007




Cortex-M3 microprocessor and NVIC. Nested interrupts are synthesized when the interrupts have the same priority, increasing priorities, and decreasing priorities. With increasing priorities, preemption will occur; in the other two cases tail-chaining will occur. The currently pending interrupts and the currently executing interrupt will be displayed on the OLED; GPIO pins B0, B1 and B2 will be asserted upon interrupt handler entry and de-asserted before interrupt handler exit so that the off-to-on time can be observed with a scope or logic analyzer to see the speed of tail-chaining (for the two cases where tail-chaining is occurring).

PWM (pwmgen)

This example application utilizes the PWM peripheral to output a 25% duty cycle PWM signal and a 75% duty cycle PWM signal, both at 440 Hz. Once configured, the application enters an infinite loop, doing nothing while the PWM peripheral continues to output its signals.

EK-LM3S1968 Quickstart Application (qs_ek-lm3s1968)

A game in which a blob-like character tries to find its way out of a maze. The character starts in the middle of the maze and must find the exit, which will always be located at one of the four corners of the maze. Once the exit to the maze is located, the character is placed into the middle of a new maze and must find the exit to that maze; this repeats endlessly.

The game is started by pressing the select push button on the right side of the board. During game play, the select push button will fire a bullet in the direction the character is currently facing, and the navigation push buttons on the left side of the board will cause the character to walk in the corresponding direction.

Populating the maze are a hundred spinning stars that mindlessly attack the character. Contact with one of these stars results in the game ending, but the stars go away when shot.

Score is accumulated for shooting the stars and for finding the exit to the maze. The game lasts for only one character, and the score is displayed on the virtual UART at 115,200, 8-N-1 during game play and will be displayed on the screen at the end of the game.

Since the OLED display on the evaluation board has burn-in characteristics similar to a CRT, the application also contains a screen saver. The screen saver will only become active if two minutes have passed without the user push button being pressed while waiting to start the game (i.e. it will never come on during game play). Qix-style bouncing lines are drawn on the display by the screen saver.

After two minutes of running the screen saver, the processor will enter hibernation mode, and the red LED will turn on. Hibernation mode will be exited by pressing the select push button. The select push button will then need to be pressed again to start the game.

Timer (timers)

This example application demonstrates the use of the timers to generate periodic interrupts. One timer is set up to interrupt once per second and the other to interrupt twice per second; each

October 11, 2007 341

EK-LM3S1968 Example Applications interrupt handler will toggle its own indicator on the display.

UART (uart_echo)

This example application utilizes the UART to echo text. The first UART (connected to the FTDI virtual serial port on the evaluation board) will be configured in 115,200 baud, 8-n-1 mode. All characters received on the UART are transmitted back to the UART.

Watchdog (watchdog)

This example application demonstrates the use of the watchdog as a simple heartbeat for the system. If the watchdog is not periodically fed, it will reset the system. Each time the watchdog is fed, the LED is inverted so that it is easy to see that it is being fed, which occurs once every second.

342 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345

30.1

Introduction


There is a board specific driver for the OSRAM 128x64 4-bit gray-scale OLED graphical display on the Stellaris LM3S2965 Evaluation Kit boards.

30.2

API Functions

Functions void

OSRAM128x64x4Clear

(void) void

OSRAM128x64x4Disable

(void) void

OSRAM128x64x4DisplayOff

(void) void

OSRAM128x64x4DisplayOn

(void) void

OSRAM128x64x4Enable


OSRAM128x64x4ImageDraw


OSRAM128x64x4Init


OSRAM128x64x4StringDraw


30.2.1



30.2.2


30.2.2.1 OSRAM128x64x4Clear


October 11, 2007 343


Prototype:

void

OSRAM128x64x4Clear(void)

Description:


Returns:

None.

30.2.2.2 OSRAM128x64x4Disable


Prototype:

void

OSRAM128x64x4Disable(void)

Description:


Returns:

None.

30.2.2.3 OSRAM128x64x4DisplayOff


Prototype:

void

OSRAM128x64x4DisplayOff(void)

Description:


Returns:

None.

30.2.2.4 OSRAM128x64x4DisplayOn


Prototype:

void

OSRAM128x64x4DisplayOn(void)

344 October 11, 2007


Description:


Returns:

None.

30.2.2.5 OSRAM128x64x4Enable


Prototype:

void

OSRAM128x64x4Enable(unsigned long ulFrequency)

Parameters:


Description:


Returns:

None.

30.2.2.6 OSRAM128x64x4ImageDraw


Prototype:

void

OSRAM128x64x4ImageDraw(const unsigned char *pucImage, unsigned long ulX, unsigned long ulY, unsigned long ulWidth, unsigned long ulHeight)

Parameters:






Description:


The image data is organized with the first row of image data appearing left to right, followed immediately by the second row of image data. Each byte contains the data for two columns in

October 11, 2007 345

EK-LM3S2965 Example Applications the current row, with the leftmost column being contained in bits 7:4 and the rightmost column being contained in bits 3:0.



+-------------------+-------------------+-------------------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 12 | Byte 13 | Byte 14 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 15 | Byte 16 | Byte 17 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 18 | Byte 19 | Byte 20 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

Returns:

None.

30.2.2.7 OSRAM128x64x4Init


Prototype:

void

OSRAM128x64x4Init(unsigned long ulFrequency)

Parameters:


Description:


Returns:

None.

346 October 11, 2007


30.2.2.8 OSRAM128x64x4StringDraw


Prototype:

void

OSRAM128x64x4StringDraw(const char *pcStr, unsigned long ulX, unsigned long ulY, unsigned char ucLevel)

Parameters:





Description:


"m" or "w".


Note:


Returns:

None.

30.3

Examples



Blinky (blinky)


October 11, 2007 347


CAN Device Board LED Application (can_device_led)

This simple application uses the two buttons on the board as a light switch. When the "up" button is pressed the status LED will turn on. When the "down" button is pressed, the status LED will turn off.

CAN Device Board Quickstart Application (can_device_qs)

This application uses the CAN controller to communicate with the evaluation board that is running the example game. It receives messages over CAN to turn on, turn off, or to pulse the LED on the device board. It also sends CAN messages when either of the up and down buttons are pressed or released.







Hello World (hello)





348 October 11, 2007


PWM (pwmgen)







If the CAN device board is attached and is running the can_device_qs application, the volume of the music and sound effects can be adjusted over CAN with the two push buttons on the target board. The LED on the CAN device board will track the state of the LED on the main board via

CAN messages. The operation of the game will not be affected by the absence of the CAN device board.


After two minutes of running the screen saver, the display will be turned off and the user LED will blink. Either mode of screen saver (bouncing lines or blank display) will be exited by pressing the select push button. The select push button will then need to be pressed again to start the game.

Timer (timers)

This example application demonstrates the use of the timers to generate periodic interrupts. One timer is set up to interrupt once per second and the other to interrupt twice per second; each interrupt handler will toggle its own indicator on the display.

UART (uart_echo)

This example application utilizes the UART to echo text. The first UART (connected to the FTDI virtual serial port on the evaluation board) will be configured in 115,200 baud, 8-n-1 mode. All

October 11, 2007 349

EK-LM3S2965 Example Applications characters received on the UART are transmitted back to the UART.

Watchdog (watchdog)


350 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

31.1

Introduction


There is a board specific driver for the OSRAM 128x64 4-bit gray-scale OLED graphical display on the Stellaris LM3S6965 Evaluation Kit boards.

These examples and display driver are for the EK-LM3S6965 Rev A boards, which utilize the

128x64 OSRAM display. The Rev A boards can be identified by looking on the back of the circuit board opposite the JTAG header. The board part number is located there and will end with an

"A". If the board part number ends with a "C", then refer instead to the examples chapter for the

EK-LM3S6965 Rev C Example Applications .

31.2

API Functions

Functions void

OSRAM128x64x4Clear

(void) void

OSRAM128x64x4Disable

(void) void


(void) void


(void) void

OSRAM128x64x4Enable




OSRAM128x64x4Init




31.2.1



October 11, 2007 351


31.2.2




Prototype:

void


Description:


Returns:

None.

31.2.2.2 OSRAM128x64x4Disable


Prototype:

void

OSRAM128x64x4Disable(void)

Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.

352 October 11, 2007




Prototype:

void


Description:


Returns:

None.

31.2.2.5 OSRAM128x64x4Enable


Prototype:

void

OSRAM128x64x4Enable(unsigned long ulFrequency)

Parameters:


Description:


Returns:

None.



Prototype:

void

OSRAM128x64x4ImageDraw(const unsigned char *pucImage, unsigned long ulX, unsigned long ulY, unsigned long ulWidth, unsigned long ulHeight)

Parameters:





October 11, 2007 353



Description:





+-------------------+-------------------+-------------------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 12 | Byte 13 | Byte 14 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 15 | Byte 16 | Byte 17 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 18 | Byte 19 | Byte 20 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

Returns:

None.



Prototype:

void

OSRAM128x64x4Init(unsigned long ulFrequency)

Parameters:


354 October 11, 2007


Description:


Returns:

None.



Prototype:

void

OSRAM128x64x4StringDraw(const char *pcStr, unsigned long ulX, unsigned long ulY, unsigned char ucLevel)

Parameters:





Description:


"m" or "w".


Note:


Returns:

None.

31.3

Examples


This example application demonstrates the use of the bit-banding capabilities of the Cortex-M3 microprocessor. All of SRAM and all of the peripherals reside within bit-band regions, meaning that

October 11, 2007 355

EK-LM3S6965 Example Applications bit-banding operations can be applied to any of them. In this example, a variable in SRAM is set to a particular value one bit at a time using bit-banding operations (it would be more efficient to do a single non-bit-banded write; this simply demonstrates the operation of bit-banding).

Blinky (blinky)


Ethernet with lwIP (enet_lwip)

This example application demonstrates the operation of the Stellaris Ethernet controller using the lwIP TCP/IP Stack. DHCP is used to obtain an ethernet address. If DHCP times out without obtaining an address, a static IP address will be used. The DHCP timeout and the default static

IP are easily configurable using macros. The address that is selected will be shown on the OLED display.

The file system code will first check to see if an SD card has been plugged into the microSD slot. If so, all file requests from the web server will be directed to the SD card. Otherwise, a default set of pages served up by an internal file system will be used.

For additional details on lwIP, http://www.sics.se/

∼adam/lwip/ refer to the lwIP web page at:

Ethernet IEEE 1588 (PTPd) with lwIP (enet_ptpd)



A default set of pages will be served up by an internal file system and the httpd server.

The IEEE 1588 (PTP) software has been enabled in this code to synchronize the internal clock to a network master clock source.



For additional details on the PTPd software, refer to the PTPd web page at: http://ptpd.sourceforge.net

Ethernet with uIP (enet_uip)

This example application demonstrates the operation of the Stellaris Ethernet controller using the uIP TCP/IP Stack. A basic web site is served over the ethernet port, located at link local address

169.254.19.63. If a node on the network has already chosen this link local address, nothing is done by the application to choose another address and a conflict will occur. The web site displays a few lines of text, and a counter that increments each time the page is sent.

356 October 11, 2007


For additional details on uIP, refer to the uIP web page at: http://www.sics.se/

∼adam/uip/







Hello World (hello)





PWM (pwmgen)



A game in which a blob-like character tries to find its way out of a maze. The character starts in the middle of the maze and must find the exit, which will always be located at one of the four corners

October 11, 2007 357

EK-LM3S6965 Example Applications of the maze. Once the exit to the maze is located, the character is placed into the middle of a new maze and must find the exit to that maze; this repeats endlessly.




A small web site is provided by the game over the ethernet port. DHCP is used to obtain an ethernet address. If DHCP times out without obtaining an address, a static IP address will be used. The

DHCP timeout and the default static IP are easily configurable using macros. The address that is selected will be shown on the OLED display before the game starts. The web pages allow the entire game maze to be viewed, along with the character and stars; the display is generated by a

Java applet that is downloaded from the game (therefore requiring that Java be installed in the web browser). The volume of the game music and sound effects can also be adjusted.



SD card using FAT file system (sd_card)

This example application demonstrates reading a file system from an SD card. It makes use of

FatFs, a FAT file system driver. It provides a simple command console via a serial port for issuing commands to view and navigate the file system on the SD card.

The first UART, which is connected to the FTDI virtual serial port on the Stellaris LM3S6965 Evaluation Board, is configured for 115,200 bits per second, and 8-n-1 mode. When the program is started a message will be printed to the terminal. Type "help" for command help.

For additional details about FatFs, http://elm-chan.org/fsw/ff/00index_e.html

see the following site:

Timer (timers)


358 October 11, 2007


UART (uart_echo)


Watchdog (watchdog)


October 11, 2007 359


360 October 11, 2007


32 EK-LM3S6965 Rev C Example Applications

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363

32.1

Introduction

The EK-LM3S6965 Rev C example applications show how to utilize features of the Cortex-M3 microprocessor, the peripherals on the Stellaris microcontroller, and the drivers provided by the peripheral driver library. These applications are intended for demonstration and as a starting point for new applications.

There is a board specific driver for the RiTdisplay 128x96 4-bit gray-scale OLED graphical display on the Stellaris LM3S6965 Rev C Evaluation Kit boards.

These examples and display driver are for the EK-LM3S6965 Rev C boards, which utilize the

128x96 RiTdisplay display. The Rev C boards can be identified by looking on the back of the circuit board opposite the JTAG header. The board part number is located there and will end with an "C". If the board part number ends with a "A", then refer instead to the examples chapter for the

EK-LM3S6965 Example Applications .

32.2

API Functions

Functions void

RIT128x96x4Clear

(void) void

RIT128x96x4Disable

(void) void


(void) void


(void) void

RIT128x96x4Enable




RIT128x96x4Init




32.2.1



October 11, 2007 361

EK-LM3S6965 Rev C Example Applications

32.2.2


32.2.2.1 RIT128x96x4Clear


Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.

362 October 11, 2007




Prototype:

void


Description:


Returns:

None.



Prototype:

void


Parameters:


Description:


Returns:

None.



Prototype:

void


Parameters:





October 11, 2007 363



Description:





+-------------------+-------------------+-------------------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 12 | Byte 13 | Byte 14 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 15 | Byte 16 | Byte 17 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 18 | Byte 19 | Byte 20 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

Returns:

None.

32.2.2.7 RIT128x96x4Init


Prototype:

void


Parameters:


364 October 11, 2007


Description:


Returns:

None.



Prototype:

void


Parameters:





Description:


"m" or "w".


Note:


Returns:

None.

32.3

Examples


This example application demonstrates the use of the bit-banding capabilities of the Cortex-M3 microprocessor. All of SRAM and all of the peripherals reside within bit-band regions, meaning that

October 11, 2007 365

EK-LM3S6965 Rev C Example Applications bit-banding operations can be applied to any of them. In this example, a variable in SRAM is set to a particular value one bit at a time using bit-banding operations (it would be more efficient to do a single non-bit-banded write; this simply demonstrates the operation of bit-banding).

Blinky (blinky)



















366 October 11, 2007



∼adam/uip/







Hello World (hello)





PWM (pwmgen)


EK-LM3S6965 Rev C Quickstart Application (qs_ek-lm3s6965_revc)

A game in which a blob-like character tries to find its way out of a maze. The character starts in the middle of the maze and must find the exit, which will always be located at one of the four corners

October 11, 2007 367

EK-LM3S6965 Rev C Example Applications of the maze. Once the exit to the maze is located, the character is placed into the middle of a new maze and must find the exit to that maze; this repeats endlessly.












The first UART, which is connected to the FTDI virtual serial port on the Stellaris LM3S6965 Evaluation Board, is configured for 115,200 bits per second, and 8-n-1 mode. When the program is started a message will be printed to the terminal. Type "help" for command help.



Timer (timers)


368 October 11, 2007


UART (uart_echo)


Watchdog (watchdog)


October 11, 2007 369


370 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373

33.1

Introduction


There is a board specific driver for the OSRAM 96x16 OLED graphical display on the Stellaris

LM3S811 Evaluation Kit board.

33.2

API Functions

Functions void

OSRAM96x16x1Clear

(void) void


(void) void


(void) void



OSRAM96x16x1Init

(tBoolean bFast) void


(const char ∗pcStr, unsigned long ulX, unsigned long ulY)

33.2.1



There are macros to map the old function names for the OSRAM driver to the new function names

(such as OSRAMInit to OSRAM96x16x1Init). The new names are more descriptive of the panel type in use; the macros for the old names are provided for backward compatibility.

33.2.2




October 11, 2007 371


Prototype:

void


Description:

This function will clear the display. All pixels in the display will be turned off.

Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void

OSRAM96x16x1ImageDraw(const unsigned char *pucImage, unsigned long ulX,

372 October 11, 2007

Stellaris Peripheral Driver Library User’s Guide unsigned long ulY, unsigned long ulWidth, unsigned long ulHeight)

Parameters:



ulY is the vertical position to display this image, specified in eight scan line blocks from the top of the display (i.e. only 0 and 1 are valid).


ulHeight is the height of the image, specified in eight row blocks (i.e. only 1 and 2 are valid).

Description:

This function will display a bitmap graphic on the display. The image to be displayed must be a multiple of eight scan lines high (i.e. one row) and will be drawn at a vertical position that is a multiple of eight scan lines (i.e. scan line zero or scan line eight, corresponding to row zero or row one).

The image data is organized with the first row of image data appearing left to right, followed immediately by the second row of image data. Each byte contains the data for the eight scan lines of the column, with the top scan line being in the least significant bit of the byte and the bottom scan line being in the most significant bit of the byte.

For example, an image four columns wide and sixteen scan lines tall would be arranged as follows (showing how the eight bytes of the image would appear on the display):

+-------+ +-------+ +-------+ +-------+

| | 0 | | | 0 | | | 0 | | | 0 |

| B | 1 | | B | 1 | | B | 1 | | B | 1 |

| y | 2 | | y | 2 | | y | 2 | | y | 2 |

| t | 3 | | t | 3 | | t | 3 | | t | 3 |

| e | 4 | | e | 4 | | e | 4 | | e | 4 |

| | 5 | | | 5 | | | 5 | | | 5 |

| 0 | 6 | | 1 | 6 | | 2 | 6 | | 3 | 6 |

| | 7 | | | 7 | | | 7 | | | 7 |

+-------+ +-------+ +-------+ +-------+

+-------+ +-------+ +-------+ +-------+

| | 0 | | | 0 | | | 0 | | | 0 |

| B | 1 | | B | 1 | | B | 1 | | B | 1 |

| y | 2 | | y | 2 | | y | 2 | | y | 2 |

| t | 3 | | t | 3 | | t | 3 | | t | 3 |

| e | 4 | | e | 4 | | e | 4 | | e | 4 |

| | 5 | | | 5 | | | 5 | | | 5 |

| 4 | 6 | | 5 | 6 | | 6 | 6 | | 7 | 6 |

| | 7 | | | 7 | | | 7 | | | 7 |

+-------+ +-------+ +-------+ +-------+

Returns:

None.



October 11, 2007 373


Prototype:

void

OSRAM96x16x1Init(tBoolean bFast)

Parameters:

bFast is a boolean that is true if the I2C interface should be run at 400 kbps and false if it should be run at 100 kbps.

Description:

This function initializes the I2C interface to the OLED display and configures the SSD0303 controller on the panel.

Returns:

None.



Prototype:

void

OSRAM96x16x1StringDraw(const char *pcStr, unsigned long ulX, unsigned long ulY)

Parameters:



ulY is the vertical position to display the string, specified in eight scan line blocks from the top of the display (i.e. only 0 and 1 are valid).

Description:


"m" or "w".


Returns:

None.

374 October 11, 2007


33.3

Examples



Blinky (blinky)






Hello World (hello)




Cortex-M3 microprocessor and NVIC. Nested interrupts are synthesized when the interrupts have the same priority, increasing priorities, and decreasing priorities. With increasing priorities, preemption will occur; in the other two cases tail-chaining will occur. The currently pending interrupts and the currently executing interrupt will be displayed on the LCD; GPIO pins D0 through D2 will be asserted upon interrupt handler entry and de-asserted before interrupt handler exit so that the off-to-on time can be observed with a scope or logic analyzer to see the speed of tail-chaining (for the two cases where tail-chaining is occurring).

October 11, 2007 375


PWM (pwmgen)



A game in which a ship is navigated through an endless tunnel. The potentiometer is used to move the ship up and down, and the user push button is used to fire a missile to destroy obstacles in the tunnel. Score accumulates for survival and for destroying obstacles. The game lasts for only one ship; the score is displayed on the virtual UART at 115,200, 8-N-1 during game play and will be displayed on the screen at the end of the game.

Since the OLED display on the evaluation board has burn-in characteristics similar to a CRT, the application also contains a screen saver. The screen saver will only become active if two minutes have passed without the user push button being pressed while waiting to start the game (i.e. it will never come on during game play). An implementation of the Game of Life is run with a field of random data as the seed value.

After two minutes of running the screen saver, the display will be turned off and the user LED will blink. Either mode of screen saver (Game of Life or blank display) will be exited by pressing the user push button. The button will then need to be pressed again to start the game.

Timer (timers)


UART (uart_echo)

This example application utilizes the UART to echo text. The first UART (connected to the FTDI virtual serial port on the Stellaris LM3S811 Evaluation Board) will be configured in 115,200 baud,

8-n-1 mode. All characters received on the UART are transmitted back to the UART.

Watchdog (watchdog)

This example application demonstrates the use of the watchdog as a simple heartbeat for the system. If the watchdog is not periodically fed, it will reset the system. Each time the watchdog is fed, the LED connected to port C5 is inverted so that it is easy to see that it is being fed, which occurs once every second.

376 October 11, 2007



Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

??

API Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

34.1

Introduction


There is a board specific driver for the RiTdisplay 128x96 4-bit gray-scale OLED graphical display on the Stellaris LM3S8962 Evaluation Kit board.

34.2

API Functions

Functions void

RIT128x96x4Clear

(void) void

RIT128x96x4Disable

(void) void


(void) void


(void) void

RIT128x96x4Enable




RIT128x96x4Init




34.2.1



34.2.2


34.2.2.1 RIT128x96x4Clear


October 11, 2007 377


Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


Description:


Returns:

None.



Prototype:

void


378 October 11, 2007


Description:


Returns:

None.



Prototype:

void


Parameters:


Description:


Returns:

None.



Prototype:

void


Parameters:






Description:


The image data is organized with the first row of image data appearing left to right, followed immediately by the second row of image data. Each byte contains the data for two columns in

October 11, 2007 379

EK-LM3S8962 Example Applications the current row, with the leftmost column being contained in bits 7:4 and the rightmost column being contained in bits 3:0.



+-------------------+-------------------+-------------------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+


+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 12 | Byte 13 | Byte 14 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 15 | Byte 16 | Byte 17 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

| Byte 18 | Byte 19 | Byte 20 |

+---------+---------+---------+---------+---------+---------+

| 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 | 7 6 5 4 | 3 2 1 0 |

+---------+---------+---------+---------+---------+---------+

Returns:

None.

34.2.2.7 RIT128x96x4Init


Prototype:

void


Parameters:


Description:


Returns:

None.

380 October 11, 2007




Prototype:

void


Parameters:





Description:


"m" or "w".


Note:


Returns:

None.

34.3

Examples



Blinky (blinky)


October 11, 2007 381


CAN Device Board LED Application (can_device_led)

This simple application uses the two buttons on the board as a light switch. When the "up" button is pressed the status LED will turn on. When the "down" button is pressed, the status LED will turn off.

CAN Device Board Quickstart Application (can_device_qs)

This application uses the CAN controller to communicate with the evaluation board that is running the example game. It receives messages over CAN to turn on, turn off, or to pulse the LED on the device board. It also sends CAN messages when either of the up and down buttons are pressed or released.















382 October 11, 2007






∼adam/uip/







Hello World (hello)





PWM (pwmgen)

This example application utilizes the PWM peripheral to output a 25% duty cycle PWM signal and a 75% duty cycle PWM signal, both at 440 Hz. Once configured, the application enters an infinite

October 11, 2007 383

EK-LM3S8962 Example Applications loop, doing nothing while the PWM peripheral continues to output its signals.









If the CAN device board is attached and is running the can_device_qs application, the volume of the music and sound effects can be adjusted over CAN with the two push buttons on the target board. The LED on the CAN device board will track the state of the LED on the main board via

CAN messages. The operation of the game will not be affected by the absence of the CAN device board.






The first UART, which is connected to the FTDI virtual serial port on the Stellaris LM3S6965 Evaluation Board, is configured for 115,200 bits per second, and 8-n-1 mode. When the program is

384 October 11, 2007

Stellaris Peripheral Driver Library User’s Guide started a message will be printed to the terminal. Type "help" for command help.



Timer (timers)


UART (uart_echo)


Watchdog (watchdog)


October 11, 2007 385

Company Information

Founded in 2004, Luminary Micro, Inc. designs, markets, and sells ARM Cortex-M3-based microcontrollers (MCUs). Austin, Texas-based Luminary Micro is the lead partner for the Cortex-M3 processor, delivering the world’s first silicon implementation of the Cortex-M3 processor. Luminary

Micro’s introduction of the Stellaris family of products provides 32-bit performance for the same price as current 8- and 16-bit microcontroller designs. With entry-level pricing at $1.00 for an ARM technology-based MCU, Luminary Micro’s Stellaris product line allows for standardization that eliminates future architectural upgrades or software tool changes.

Luminary Micro, Inc.

108 Wild Basin, Suite 350

Austin, TX 78746

Main: +1-512-279-8800

Fax: +1-512-279-8879 http://www.luminarymicro.com

[email protected]

Support Information

For support on Luminary Micro products, contact: [email protected]

+1-512-279-8800, ext 3

386 October 11, 2007

Stellaris Peripheral Driver Library User's Guide

Stellaris® Peripheral Driver Library

USER’S GUIDE

Legal Disclaimers and Trademark Information

Revision Information

Table of Contents

1

Introduction

2

Analog Comparator

3

Analog to Digital Converter

4

Controller Area Network (CAN)

5

Ethernet Controller

6

Flash

7

GPIO

8

Hibernation Module

9

I2C

10 Interrupt Controller

11 Pulse Width Modulator

12 Quadrature Encoder

13 Synchronous Serial Interface

14 System Control

15 SysTick

16 Timer

17 UART

18 Watchdog Timer

19 Error Handling

20 DK-LM3S101 Example Applications

21 DK-LM3S102 Example Applications

22 DK-LM3S301 Example Applications

23 DK-LM3S801 Example Applications

24 DK-LM3S811 Example Applications

25 DK-LM3S815 Example Applications

26 DK-LM3S817 Example Applications

27 DK-LM3S818 Example Applications

28 DK-LM3S828 Example Applications

29 EK-LM3S1968 Example Applications

30 EK-LM3S2965 Example Applications

31 EK-LM3S6965 Example Applications

32 EK-LM3S6965 Rev C Example Applications

33 EK-LM3S811 Example Applications

34 EK-LM3S8962 Example Applications

Company Information

Support Information

Related manuals

Luminary Micro

Stellaris LM3S8962