Beginning C for Arduino

276 Pages·2012·26.99 MB·English

Beginning C for Arduino
Learn C Programming for the Arduino and Compatible Microcontrollers Technology in AcTion™
Beginning C
harness the processing power of the microcontroller and learn how Also available:
to control your own electronic devices with Beginning C for Arduino.
Written for individuals who have no prior experience with microcontrollers
or programming, this book teaches you tried and true coding practices that B
will help you become a fearless tinkerer.
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led by an engaging, expert programmer, with more than 25 years of
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university teaching experience, you’ll discover how to use the c program- Arduino
ming language to control the Arduino (Atmel) family of microcontrollers i
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as well as Arduino-compatible boards. each step of the way, a simple,
inexpensive, hardware experiment demonstrates the language in action. n
This provides you with a deep understanding of what the code is doing
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and how it is done. n
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With Beginning C for Arduino, you’ll learn how to:
Learn C Programming for the Arduino
C
• Use the syntax of the c programming language as defined for the Arduino

• Design, code, and debug programs that drive Arduino microcontrollers f and Compatible Microcontrollers
• extend the functionality of c by creating your own library routines o
• Detect, isolate, and fix program bugs r

• implement multiple solutions for any given programming problem A
• integrate low-cost, off-the-shelf, hardware shields into your own projects
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Beginning C for Arduino blends a software and hardware learning experi-
u Take complete control of your Arduino
ence into a single, enjoyable endeavor. it offers you an engaging, take-at-
with the power of C
your-own-pace way to learn the fundamental programming concepts that i
n
will fuel your future creations.
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US $39.99 u
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Shelve in Computer Hardware/General
User level: Beginning-Intermediate
SOURCE CODE ONLINE Ph.D. Jack Purdum
www.apress.com
Beginning C for Arduino
n n n
Jack Purdum
Beginning C for Arduino
Copyright © 2012 by Jack Purdum
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying, recording, or by any information storage or retrieval
system, without the prior written permission of the copyright owner and the publisher.
ISBN-13 (pbk): 978-1-4302-4776-0
ISBN-13 (electronic): 978-1-4302-4777-7
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ii
To Jane for her unwavering support during this project.
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Contents at a Glance
 About the Author ................................................................................................................xiii
 About the Technical Reviewer ............................................................................................xiv
 Acknowledgments ...............................................................................................................xv
 Introduction ........................................................................................................................xvi
 Chapter 1: Introduction .........................................................................................................1
 Chapter 2: Arduino C ...........................................................................................................21
 Chapter 3: Arduino C Data Types ........................................................................................37
 Chapter 4: Decision Making in C .........................................................................................55
 Chapter 5: Program Loops in C ...........................................................................................77
 Chapter 6: Functions in C ....................................................................................................91
 Chapter 7: Storage Classes and Scope .............................................................................113
 Chapter 8: Introduction to Pointers ..................................................................................131
 Chapter 9: Using Pointers Effectively ...............................................................................151
 Chapter 10: Structures, Unions, and Data Storage ...........................................................171
 Chapter 11: The C Preprocessor and Bitwise Operations ................................................197
 Chapter 12: Arduino Libraries ...........................................................................................211
 Appendix A: Suppliers and Sources..................................................................................231
 Appendix B: Electronic Components for Experiments .....................................................237
 Answers to Exercises ........................................................................................................241
 Index ..................................................................................................................................257
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Contents
 About the Author ................................................................................................................xiii
 About the Technical Reviewer ............................................................................................xiv
 Acknowledgments ...............................................................................................................xv
 Introduction ........................................................................................................................xvi
 Chapter 1: Introduction .........................................................................................................1
Assumptions About You ..........................................................................................................2
What You Need .......................................................................................................................3
An Atmel-Based Microcontroller Card ............................................................................................................3
Breadboard .....................................................................................................................................................5
Miscellaneous Parts .......................................................................................................................................6
Verifying the Software ............................................................................................................6
Verifying the Hardware ...........................................................................................................8
Attaching the USB Cable .................................................................................................................................8
Selecting Your mc Board in the Integrated Development Environment ...........................................................9
Port Selection ...............................................................................................................................................10
Loading and Running Your First Program ............................................................................13
The Blink Program .......................................................................................................................................14
Running the Blink Program Code ..................................................................................................................16
Compiling the Blink Program Code ...............................................................................................................17
Uploading the Blink Program .......................................................................................................................18
Summary ..............................................................................................................................20
 Chapter 2: Arduino C ...........................................................................................................21
The Building Blocks of All Programming Languages ............................................................21
Expressions ..................................................................................................................................................21
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Statements ...................................................................................................................................................23
Statement Blocks .........................................................................................................................................24
Function Blocks ............................................................................................................................................25
The Five Program Steps .......................................................................................................26
1. Initialization Step ......................................................................................................................................26
2. Input Step .................................................................................................................................................26
3. Process Step .............................................................................................................................................26
4. Output Step ...............................................................................................................................................27
5. Termination Step .......................................................................................................................................27
The Purpose of the Five Program Steps .......................................................................................................27
A Revisit to the Blink Program ..............................................................................................28
Program Comments ......................................................................................................................................29
Data Definition ..............................................................................................................................................30
The setup() Function ....................................................................................................................................32
The loop() Function ......................................................................................................................................34
Summary ..............................................................................................................................35
Exercises ..............................................................................................................................36
 Chapter 3: Arduino C Data Types ........................................................................................37
Keywords in C ...............................................................................................................................................38
Variable Names in C .....................................................................................................................................38
The boolean Data Type .........................................................................................................39
The char Data Type ...............................................................................................................39
Binary Data ...................................................................................................................................................39
The char Data Type and Character Sets ........................................................................................................40
Generating a Table of ASCII Characters ........................................................................................................41
The byte Data Type ...............................................................................................................42
The int Data Type ..................................................................................................................43
The word Data Type ..............................................................................................................43
The long Data type ...............................................................................................................43
The float and double Data Types ..........................................................................................43
Floating Point Precision ................................................................................................................................44
The string Data Type .............................................................................................................44
String Data Type ...................................................................................................................45
The void Data Type ...............................................................................................................46
The array Data Type ..............................................................................................................47
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Defining versus Declaring Variables .....................................................................................47
Symbol Tables ...............................................................................................................................................47
lvalues and rvalues .......................................................................................................................................48
The Bucket Analogy ......................................................................................................................................50
Using the cast Operator ........................................................................................................52
Summary ..............................................................................................................................53
Exercises ..............................................................................................................................54
 Chapter 4: Decision Making in C .........................................................................................55
Relational Operators .............................................................................................................55
The if Statement ...................................................................................................................56
A Modified Blink Program .....................................................................................................58
The Circuit ....................................................................................................................................................59
The Program Code ........................................................................................................................................60
Software Modifications to the Alternate Blink Program ...................................................61
The if-else Statement ...........................................................................................................62
Cascading if Statements ......................................................................................................63
The Increment and Decrement Operators ............................................................................65
Two Types of Increment Operator (++) .........................................................................................................65
Two Flavors of the Decrement Operator (--) .................................................................................................66
Precedence of Operators ..............................................................................................................................66
The switch Statement ..........................................................................................................67
The goto Statement .............................................................................................................68
Getting Rid of Magic Numbers .............................................................................................68
The C Preprocessor .............................................................................................................68
Heads or Tails .......................................................................................................................71
Initialization Step ..........................................................................................................................................71
Input Step .....................................................................................................................................................71
Process Step .................................................................................................................................................71
Output Step ...................................................................................................................................................71
Termination Step ..........................................................................................................................................72
Something to Think About ....................................................................................................74
Summary ..............................................................................................................................75
Exercises ..............................................................................................................................76
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 Chapter 5: Program Loops in C ...........................................................................................77
The Characteristics of Well-Behaved Loops .........................................................................77
Condition 1: Variable Initialization .................................................................................................................77
Condition 2: Loop Control Test .....................................................................................................................78
Condition 3: Changing the Loop Control Variable’s State .............................................................................78
Using a for Loop ...................................................................................................................78
The while Loop .....................................................................................................................80
The do-while Loop ................................................................................................................81
The break and continue Keywords .......................................................................................82
The break Statement ...................................................................................................................................82
The continue Statement ...............................................................................................................................83
A Complete Code Example ...................................................................................................84
Step 1. Initialization ......................................................................................................................................85
Step 2. Input .................................................................................................................................................85
Step 3. Process ............................................................................................................................................85
Step 4. Output ...............................................................................................................................................85
Step 5. Termination .......................................................................................................................................85
Listing 5-1 is Sorta Dumb Code ....................................................................................................................87
Loops and Coding Style ........................................................................................................88
Summary ..............................................................................................................................89
Exercises ..............................................................................................................................90
 Chapter 6: Functions in C ....................................................................................................91
The Anatomy of a Function ..................................................................................................92
Function Type Specifier ................................................................................................................................92
Function Name .............................................................................................................................................92
Function Arguments .....................................................................................................................................93
Function Body ...............................................................................................................................................94
Function Signature ......................................................................................................................................95
What Makes a “Good” Function ...........................................................................................96
Functions Use Task-Oriented Names ............................................................................................................96
The Function Should Be Cohesive ................................................................................................................96
Functions Should Avoid Coupling .................................................................................................................97
Writing Your Own Functions .................................................................................................97
Function Design Considerations ...................................................................................................................98
Argument List ...............................................................................................................................................99
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Function Body ...............................................................................................................................................99
Logical Operators ...............................................................................................................100
Logical AND Operator (&&) ..........................................................................................................................100
Logical OR (||) ..............................................................................................................................................101
Logical NOT (!) ............................................................................................................................................101
Writing Your Function .........................................................................................................102
The IsLeapYear() Function and Coding Style ..............................................................................................103
Arguments versus Parameters ...................................................................................................................103
Why Use a Specific Function Style? ...........................................................................................................104
Leap Year Calculation Program .........................................................................................104
Passing Data Into and Back From a Function .....................................................................107
Pass by Value ..............................................................................................................................................108
Summary ............................................................................................................................110
Exercises ............................................................................................................................111
 Chapter 7: Storage Classes and Scope .............................................................................113
Hiding Your Program Data ..................................................................................................113
Statement Block Scope ......................................................................................................113
Local Scope ........................................................................................................................116
Name Collisions and Scope ........................................................................................................................117
Global Scope .......................................................................................................................119
Global Scope and Name Conflicts ...............................................................................................................121
Scope and Storage Classes ................................................................................................121
The auto Storage Class ...............................................................................................................................121
The register Storage Class .........................................................................................................................121
The static Storage Class .............................................................................................................................122
The extern Storage Class ............................................................................................................................122
The volatile keyword ..........................................................................................................127
Summary ............................................................................................................................128
Exercises ............................................................................................................................129
 Chapter 8: Introduction to Pointers ..................................................................................131
Defining a Pointer ...............................................................................................................131
Pointer Name ..............................................................................................................................................131
Asterisk ......................................................................................................................................................132
Pointer Type Specifiers and Pointer Scalars ...............................................................................................132
Using a Pointer ...................................................................................................................136
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