Embedded Multitasking

417 Pages·2006·1.392 MB·English

by  Keith E. Curtis

Embedded
Multitasking
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Embedded
Multitasking
Keith Curtis
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Library of Congress Cataloging-in-Publication Data
Curtis, Keith, 1961-
Embedded multitasking / Keith Curtis.
p. cm.
Includes index.
ISBN 0-7506-7918-2 (pbk. : alk. paper) 1. Embedded computer systems. 2.
Computer firmware--Design. 3. Embedded computer systems--Programming. I.
Title.
TK7895.E42C87 2006
004’.35--dc22
2005029822
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.
ISBN-13: 978-0-7506-7918-3
ISBN-10: 0-7506-7918-2
For information on all Newnes publications
visit our website at www.books.elsevier.com.
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Printed in the United States of America
Dedication
Paraphrasing an old saying:
“Give a man a tool, he becomes a repair man.”
“Teach him how to make his own tools, he becomes an engineer!”
This book is dedicated to all the embedded engineers out there adding
intelligence to the everyday things in our lives.
And to my wife Shirley, who has put up with this, and all my other
projects, through a combination of patience and understanding.
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Contents
About the Author xi
What’s on the CD-ROM? xiii
1 What’s In This Book, and Why Should I Read It? 1
Engineering and Profits 4
2 Basic Embedded Programming Concepts 19
Numbering Systems 20
Binary Numbers 22
Signed Binary Numbers 23
Fixed-Point Binary Numbers 25
Floating-Point Binary Numbers 27
Alternate Numbering Systems 28
Binary-Coded Decimal 29
ASCII 30
Error Detection 32
Data Structures 33
Simple Data Types 34
Complex Data Types 43
Communications Protocols 51
Simple Data Broadcast 51
Event-Driven Single Transfer 54
Event-Driven Multielement Transfers 56
Mathematics 61
Binary Addition and Subtraction 61
Binary Multiplication 64
viii Contents
Binary Division 66
Numeric Comparison 69
Conditional Statements 71
Loops 78
Other Flow Control Statements 81
State Machines 83
Data-Indexed State Machines 89
Execution-Indexed State Machines 92
Hybrid State Machines 97
Multitasking 99
Four Basic Requirements of Multitasking 101
Context Switching 101
Communications 102
Managing Priorities 102
Timing Control 103
Operating Systems 103
State Machine Multitasking 108
3 System-Level Design 111
Dissecting the Requirements Document 113
Function List 114
Function List Questions 115
The User Interface 120
Communications 129
Timing Requirements 139
System Priorities 146
Error Handling 154
System-Level Design 157
Task Definition 158
Criteria for Compatible Software Functions 161
Criteria for Incompatible Software Functions 164
Communications 171
Timing Analysis 182
Priority Handler 189
Error Recovery 192
System-Level Design Documentation 198
Contents ix
4 Component-Level Design 203
Task State Machines 203
Communications 223
System Timing 240
Priority Handler 252
Error Recovery System 271
5 Implementation and Testing 289
Building a Testing Driver Routine 307
6 Does It Do the Job? 379
Index 383