Beginning C for Arduino: Learn C programming for the Arduino

276 Pages·2012·27.51 MB·English

by  Jack Purdum

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
r
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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,
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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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