The Microcontroller Idea Book Circuits, Programs, Applications featuring the 8052-BASIC Microcontroller Jan Axelson

291 Pages·2002·2.8 MB·english

by  Jan Axelson

The
Microcontroller Idea Book
Circuits, Programs, & Applications
featuring the 8052-BASIC Microcontroller
Jan Axelson
Lakeview Research
Madison, WI
copyright 1994, 1997 by Jan Axelson
Lakeview Research
5310 Chinook Ln.
Madison, WI 53704
USA
Phone: [phone]
Fax: [phone]
Email: [email protected]
WWW: http://www/lvr.com
No part of this book, except the programs and program listings, may be reproduced in any
form, or stored in a database or retrieval system, or transmitted or distributed in any form,
by any means, electronic, mechanical photocopying, recording, or otherwise, without the
prior written permission of Lakeview Research or the author, except as permitted by the
Copyright Act of 1976. The programs and program listings, or any portion of these, may be
stored and executed in a computer system and may be incorporated into computer programs
developed by the reader.
Trademarks
Macintosh is a registered trademark of Apple Computer. Procomm Plus and Datastorm are
registered trademarks of Datastorm Technologies, Inc. VT100 is a registered trademark of
Digital Equipment Corporation. IBM is a registered trademark of International Business
Machines Corporation. MCS-BASIC-52 and Intel are registered trademarks of Intel Corpo-
ration. Microsoft, MS-DOS, GW-BASIC, and Microsoft Windows are registered trademarks
of Microsoft Corporation. Philips is a registered trademark of Philips International BV.
The author and publisher have used their best efforts in preparing this book and the
materials in it. The author built and tested the electronic circuits described, ran and tested
the computer programs presented, and reviewed all materials for completeness and
accuracy. The author and publisher make no warranty with regard to the circuit
schematics, program listings, and other materials in this book. The author and publisher
take no responsibility for any damages resulting from any use of the material in this book.
ISBN 0-9650819-4-X
Table of Contents
Chapter 1 Microcontroller Basics 1
What’s a Microcontroller? 1
A Little History 2
New Tools 3
Project Steps 4
Chapter 2 Inside the 8052-BASIC 11
Possibilities 11
Limits 13
What You Need 14
The 8051 Family 16
Elements of the 8052 and 8052-BASIC 17
Chapter 3 Powering Up 23
About the Circuit 23
Circuit Construction 30
Powering Up 35
Basic Tests 38
Simple Programs to Try 40
Exiting Programs 44
Chapter 4 Saving Programs 47
Nonvolatile Memory Options 47
Adding NVRAM or EEPROM 50
Using the Programming Commands 53
Adding Bootup Options 54
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Erasing NV Memory 55
Adding more NVRAM or EEPROM 56
Adding EPROM 56
EPROM-programming Circuits 57
Power Supplies for Programming 61
Storing Programs on Disk 63
Chapter 5 Programming 65
Programming Basics 65
BASIC-52 Bugs and Things to Watch Out For 69
Finding Program Errors 70
BASIC-52 Keywords by Function 72
Quick Reference to BASIC-52 74
Chapter 6 Inputs and Outputs 87
The Memory Map 87
Uses for I/O Ports 89
Adding Ports 89
The 8255 Programmable Peripheral Interface 98
Chapter 7 Switches and Keypads 109
Simple Switches 109
Adding a Keypad 116
Chapter 8 Displays 125
Using LEDs 125
7-segment Displays 129
Displaying Messages 138
Inside the Display Controller 140
Mounting Displays in an Enclosure 152
Chapter 9 Using Sensors to Detect and Measure 153
Sensor Basics 153
Choosing Sensors 154
On/off Sensors 155
Analog Sensors 156
Sensor Examples 163
Level Translating 167
Choosing a Converter 169
Chapter 10 Clocks and Calendars 171
BASIC-52’s Real-time Clock 171
A Watchdog Timekeeper 174
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Chapter 11 Control Circuits 185
Switching Power to a Load 185
Controlling a Switch Matrix 187
Op Amp with Programmable Gain 189
Controlling a Stepper Motor 191
Speed Control of a Continuous DC Motor 195
Chapter 12 Wireless Links 199
Infrared Links 199
Increasing the Distance 212
Radio Links 216
Chapter 13 Calling Assembly-language Routines 217
Assembly-language Basics 218
What You Need 218
Loading a Routine 221
File Formats for Assembly-language Routines 222
Assembling a Program 224
Uploading a Program 225
Example: Creating a Sine Wave 227
Avoiding Program Crashes 231
Interrupts 232
Adding Custom Commands and Instructions 233
A General-purpose EPROM Programmer 237
Chapter 14 Running BASIC-52 from External Memory 239
Reasons 239
Copying BASIC-52 240
System Requirements 241
Storing BASIC-52 Programs 243
Chapter 15 Related Products 245
Enhanced BASIC-52 245
BASIC Compilers 246
Programming Environments 247
Pc Boards 248
BASIC-52 Source Code 250
Appendix A Sources 251
Books 251
BBS’s 254
Product Vendors 255
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Appendix B Programs for Loading Files 263
Appendix C Number Systems 271
About Number Systems 271
Kilobytes and Megabytes 273
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Introduction
Introduction
This book is a hands-on guide to designing, building, and testing microcontroller-based
devices. Microcontrollers, or single-chip computers, are ideal for projects that require
computer intelligence, but don’t need the overhead of a complete personal computer with
disk drives, keyboard, and full-screen display.
Why the 8052-BASIC?
This book focuses on the 8052-BASIC microcontroller, which is easy to use, full featured,
and inexpensive to work with. The on-chip BASIC-52 programming language enables you
to write, run, and test your programs quickly. With over 100 commands, instructions, and
operators, BASIC-52 is more capable than other microcontroller BASICs. And, as a member
of the 8051 microcontroller family, the 8052-BASIC has a standard, popular architecture.
The ideas and applications presented here are not limited to the 8052-BASIC, however. If
your favorite chip is a different one, you can adapt the circuits and programs to it. The
schematics and program listings in this book include comments and explanations to help
you apply the ideas, whether or not you are using the 8052-BASIC.
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Introduction
What’s Inside?
This is not just a textbook that presents information but glosses over the details of how to
apply it. Inside, you’ll find practical information, including the following:
•Complete circuit schematics and parts lists—so you can easily build the circuits
yourself.
•Design theory—for example, why use this particular component? or how can I expand
or modify the circuit shown?
•Example program listings—for easy testing and use of the circuits.
•Construction and debugging tips—to help you get the circuits up and running without
problems.
The appendices include a complete list of sources to help you find the components and
additional information you need for your projects.
Because microcontroller projects involve both circuit design and programming, I cover both
the hardware and software aspects. The book begins with an introduction to microcontrol-
lers, and to the 8052-BASIC chip in particular. Next are basic circuits to get you started
programming and interfacing to the chip, along with the reasons behind the component and
design choices, and construction details for prototyping. To the basic circuits, I show how
to add switches, keypads, displays, and other input/output interfaces.
A programming reference describes each of BASIC-52’s keywords, with specific tips for
trouble-free programming in BASIC-52.
You’ll also find out how to add these to your system:
•Sensors, for detecting detect and measuring physical properties.
•Clock/calendar functions, for keeping track of seconds, minutes, hours, days, months,
and years, and to trigger alarms at particular times.
•Control of AC power, switch matrices, stepper and continuous motors, and gain of an
op amp.
•Programmable wireless links, for situations where stringing wires isn’t practical or
convenient.
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Introduction
A chapter on assembly-language interfacing shows how to add assembly-language programs
for faster program execution, how to add your own commands the BASIC-52 programming
language, and how to use the 8052-BASIC as a development system for an all-assembly-
language project.
The final chapters cover other options for 8052-BASIC systems, including how to store
BASIC-52 in external memory rather than in the 8052’s internal ROM, and a review of
related products, including BASIC compilers, 8052-BASIC circuit boards, and development
software for more convenient and possibly cheaper project development.
Your Feedback Is Welcome
This book is the result of requests from readers of my articles in ComputerCraft magazine
and its successor, The MicroComputer Journal. I’ve expanded the coverage of several topics,
including programming of EPROMs and other devices, display options, sensors, and
programming tips.
Thanks to everyone who responded to my articles with comments, questions, criticisms, and
suggestions, and who, in doing so, helped to make this book as useful as it can be. As always,
I welcome your comments on this work.
Jan Axelson
10-94
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