Peripheral interface standards for microprocessors

Interfacing a peripheral to a microprocessor requires a peripheral interface attached to the processor and a controller within the peripheral, with usually a transmission link in between. Universal and special interface circuits are becoming available for an easy interface with the various microprocessor peripherals. The use of programmable interfaces increases the flexibility of the interface, and standards are necessary for reaching high-volume production. Present standards include serial EIA RS232 and the recent Hewlett-Packard Interface Bus for measuring instruments. Four new standards developed and used at the Mini and Microcomputer Laboratory of Lausanne fill a gap at the following levels: 1) microprocessor data, address, and control bus, 2) parallel data transfer, 3) simple serial data transfer with handshake, and 4) serial bus for data exchange between terminals and processors.