CONTENTS PAGE INTRODUCTION 1 DC MOTORS 1 THE 83C51FA 1 SETTING UP THE PCA 2 HARDWARE REQUIREMENTS 3 DRIVER CIRCUIT 4 NOISE CONSIDERATIONS 4 OPEN LOOP AND CLOSED LOOP SYSTEMS 5 FEEDBACK 5 SOFTWARE/CPU OVERHEAD 7 ELECTRICAL BRAKING 8 STEPPING A DC MOTOR 9 TIME DELAYS 9 CONCLUSION 11 APPENDIX A-1 This application note shows how an 83C51FA can be used to efficiently control DC motors with minimum hardware requirements. It also discusses software implementation and presents helpful techniques as well as sample code needed to realize precision control of a motor. There is also a brief overview of the new features of the 83C51FA. This new feature is called the Programmable Counter Array (PCA) and is capable of delivering Pulse Width Modulated signals (PWM) through designated I/O pins.