Motorola M6800 manual MPU-1 Introduction

MPU-1

INTRODUCTION

The Motorola M6800 Microcomputer System of standard LSI (Large Scale Integration) devices permits the systems designer to configure and connect a total system with a minimum amount of time and effort. The MC6800 Microprocessing Unit (MPU) forms the nucleus of the system. LSI modules available which may be used to configure a total system in conjunction with the MC6800 MPU, include: 1) MC6810 Random Access Memory (RAM); 2) MC6830 Read Only Memory (ROM); 3) MC6820 Peripheral Interface Adapter (PIA), and 4) MC6850 Asynchronous Communications Interface Adapter (ACIA).

The MPU communicates with the rest of the system via a 16 bit address bus and an 8 bit data bus. The 16 bit address bus provides the MPU the capability of addressing up to 64K. The 8 bit data bus is bi-directional in that data is transferred both into the MPU or out of the MPU over the same bus. A read/write (R/W) line is provided to allow the MPU to control the direction of data transfer.. Since the same bus is used for both data into the MPU or out of the MPU, a separate 8 line bus is saved.

Other features of the M6800 system include a single +5 volt supply, operation at clock rates from 100 kilohertz to 1 megahertz, plus hardware and software interrupt capability.