This book is a collection of projects based around various microcontrollers from the PIC family.  The reader is carefully guided through the book, from very simple to more complex projects in order to gradually build their knowledge about PIC microcontrollers and digital electronics in general.  On completion of this book, the reader should be able to design and build their own projects and solve other practical problems in digital electronics. Many books in this area are theory based and can tend toward being overly explanatory in their approach to the subject.  Courses are moving towards being more practically oriented and this book provides the ideal companion to students completing projects with PIC microcontrollers. Hassan Parchizadeh is a principal lecturer at the University of Portsmouth. He has been lecturing for over 20 years and currently teaches a number of subjects including microcontrollers, power electronics and signal processing. He as also published two books on microcontrollers. Dr. Branislav Vukanovic is a senior lecturer at the University of Portsmouth, previously he was a lecturer and the University of Derby and a research fellow at the University of Sheffield. He teaches in the areas of digital electronics, microprocessors and digital signal processing. He has published a significant number of papers in his fields. PIC Projects - A Practical Approach By Hassan Parchizadeh Branislay Vuksanovic John Wiley & Sons Copyright © 2009 John Wiley & Sons, Ltd All right reserved. ISBN: 978-0-470-69461-9 Chapter One Preparing to do a PIC Project 1.1 Introduction 1.2 Overview of PIC Microcontroller 1.3 Basics of PIC Assembly Language 1.4 Introduction to C Programming for PIC Microcontroller 1.5 MPLAB Integrated Development Environment (IDE) 1.6 Advanced Debugger Features - Stimulus 1.1 Introduction The aim of this chapter is to consider a number of issues that need to be taken into account before doing almost any microcontroller-based project. First, the reader will be introduced to a PIC (programmable interface controller) microcontroller by a brief discussion of one of the models from the PIC microcontroller family - the PIC16F627A. This model is now a common choice for low-cost PIC projects and has practically replaced the very popular PIC16F84 model. The PIC16F627A is therefore a choice for a large number of projects from this book although some other simpler and more complex models are also being used. The rest of the PIC family will be considered briefly, introducing some other models used for the projects in this book. We will then discuss the basics of two programming languages commonly used to develop PIC programs in practice and throughout this book - assembly and C. This will by no means be a detailed discussion of those two languages; a separate book would be needed for that. The aim instead is to provide a short overview of the basic features of both languages and to enable readers to learn the rest of it while doing projects from the other chapters of this book. Material covered in this chapter should therefore be sufficient to allow the reader to start with the first programs and projects from Chapter 2 and gradually build knowledge to domore complex projects fromthe rest of the book. Finally, we will demonstrate how to develop and test a simple PIC program using the MPLAB(r) -Integrated Development Environment (IDE). 1.2 Overview of PIC Microcontroller The name PIC denotes several families of microcontrollers manufactured by Microchip Technology. This range is huge and very versatile so discussing even a small number of microcontrollers would be a difficult and time-consuming task. Instead, in this section, we will concentrate on the basic features and layout of one of the most popular members of the mid-range PIC16 family: PIC16F627A. Once the basic features of this device are explained it will be easier to introduce and understand the operations of more complex PICs used in later chapters of this book. 1.2.1 PIC16F627 Building Blocks Every computer system, however complicated or simple, consists of a number of common building blocks. Those are: the CPU (central processing unit or microprocessor) block, the memory block (RAM and ROM) and the input/output (I/O) block (interface circuitry). The CPU performs all the logic and arithmetic functions; memory is used to store programs and data while the interface provides means of communication and data exchange between the microcomputer system and the external world. A microcontroller is a stripped-down version of the computer system architecture with one important difference - all of the system blocks are placed on one chip. The microcontroller-based system therefore requires very little additional circuitry for its proper operation. All that is needed in most cases is a clock input to provide timing for the system operation. The PIC16F27A microcontroller contains all of the previously mentioned bloc