Di Jasio - Programming 32-bit microcontrollers in C: exploring the PIC32

Programming 32-bit Microcontrollers in C

Exploring the PIC32

Lucio Di Jasio

Newnes

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ISBN: 978-0-7506-8709-6

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Dedicated to my son, Luca.

Acknowledgments

Once more this project would have never been possible if I did not have 110% support from my wife Sara, who understands my passion(s) and constantly encourages me to pursue them. Special thanks go to Steve Bowling and to Garry Champ. Their passion and experience in embedded control application caused them to volunteer for reviewing the technical content of this book. While Garry did not know what he was signing up to, Steve should have known better having been my primary technical resource for the previous book. I owe big thanks also to Patrick Johnson, who enthusiastically supported this book idea from the very beginning and pulled all the stops to make sure that I would be able to work in direct contact with his most advanced design and application teams working on the PIC32 project. Thanks to Joe Triece, the architect, for being always available to me and always curious about my experiences and impressions. Thanks to Joe Drzewiecky for assembling such a complex tool suite, always working hard to make MPLAB IDE a better tool. Special thanks also go to the entire PIC32 application team headed by Nilesh Rajbharti and a special mention to Adrian Aur, Dennis Lehman, Larry Gass and Chris Smith for addressing quickly all my questions and offering so much help and insight into the inner workings of the microcontroller, the peripherals and its libraries. But I would like to extend my gratitude to all my friends, the colleagues at Microchip Technology and the many embedded control engineers I have been honored to work with over the years. You have so profoundly influenced my work and shaped my experience in the fantastic world of embedded control.

Finally, since the publication of my previous book on Programming 16-bit microcontrollers in C, I have received so much feedback and so many readers have written to me to congratulate but also to point out errors and issues. This has been a very humbling but also rewarding experience and I want to thank you all. I tried to incorporate as many of your suggestions as possible in this new work but I am still looking for your continued support and advice.

Introduction

The first step in almost every rehabilitation program is A- Acknowledge your limitations. So this is how I need to start this book, I will admit it: I am 8-bitter!

I have been programming 8-bit microcontrollers since I was in high school and for most of my professional career. And there is worse, while I am relatively fluent in several high level programming languages, I truly love assembly programming!

There, I said it! I love that kick that I get when I know I used every single machine cycle in every microsecond my embedded applications run. I am also obsessed with control: I like to know of every configuration bit in every peripheral I use. As a consequence, in general, I dont trust compilers or other peoples libraries unless I really cannot live without them or I have them completely disassembled.

So why would I write a book about 32-bit programming in C?

In fact I started what I should call my rehabilitation program a couple of years ago by approaching the programming of 16-bit microcontrollers first. The introduction of the PIC24 family of microcontrollers gave me the motivation to try and migrate to C programming with a new and exciting architecture. As a result of my experience, I wrote the first book: Programming 16-bit microcontrollers in C. Learning to fly the PIC24. But by the time the book was published, rumors circulated in Microchip that a new 32-bit chip had just come out of the ovens and I had to have one!

Ill spare you the details of how I got my hands around one of the very first test chips, but what you need to know is that in a matter of days I had most of the code, originally developed for the PIC24 book, ported and running on the PIC32 plugged in my old Explorer16 board.

Microchip marketing folks will tell you that the PIC32 architecture was specifically designed so to make the migration from 8-bit and 16-bit PIC architectures smooth and seamless, but I had to see it with my eyes to believe it.

So who better than an assembly-loving, control-obsessed, 8-bitter can tell you about the exploration of the PIC32?

The PIC32 turns out to be a remarkably easy to use device, but nonetheless, it is a truly powerful machine based on a well established 32-bit core (MIPS) and supported by a large number of tools, libraries and documentation. This book can only offer you a small glimpse into such a vast world and in fact I call it a first exploration. It is my strong belief that learning should be fun, and I hope you will have a good time with some of the playful exercises and projects I present throughout each chapter in the book. However you will need quite some preparation and hard work in order to be able to digest the material I am presenting at a pace that will accelerate rapidly through the first few chapters.

This book is meant for programmers of a basic to intermediate level of experience, but not for absolute beginners; so dont expect me to start with the basics of the binary numbers, the hexadecimal notation or the fundamentals of programming. Although, we will briefly review the basics of C programming as it relates to the applications for the latest generation of general-purpose 32-bit microcontrollers, before moving on to more challenging projects. My assumption is that you, the reader, belong to one of the following four categories: