The TEMP Microcomputer as an Instrument Controller and Data Logger

Abstract

The microprocessor is becoming an indispensible laboratory tool. To adapt it to one’s needs requires some basic understanding of its operation. With this understanding and some inexpensive integrated circuits, one can create custom interfaces for one’s own unique requirements.

A microcomputer based on the 8085 microprocessor has been designed at this school around the objective of the teaching of skills of interfacing microprocessors to laboratory instrumentation for data acquisition and control in real time. This microcomputer is simple, powerful and inexpensive.

The microprocessor chip communicates through the system bus consisting of the address bus, the data bus, and the control bus. An address decorder selects which device the microprocessor chip communicates with over the data bus. Every device is connected to the system bus through an interface which performs any required conversion and shifting of logic levels.

Some devices are connected through standard interfaces such as the RS232 interface and the IEEE 488 interface; however other devices, such as A/D and D/A converters, relays, sensors, actuators, and clocks, may have their interfaces designed as needed. These can in many cases be designed by the user.

Useful examples are given of some commonly occurring situations whereby data may be read in or a control signal put out by a microcomputer to interact with a laboratory instrument.