Motorola M6800 User Manual

Motorola Computers

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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.