An IEEE-488 interface for the CRL-32A microcomputer

Abstract

A general-purpose input/output (I/O) interface card, which includes an IEEE-488 bus, a parallel printer, and RS-232-C interfacing circuits, was designed and constructed. This interface card was designed to expand the present I/O communication capability of the main single-board computer CRL-32A. The design of the IEEE-488 bus interface was emphasized. The I/O support routines for the three types of interfacing were written both in assembly language and Forth. A Hazeltine terminal was used to help develop the routines for RS-232-C communication. A Centronics 737-1 printer was used to help develop the I/O routines for parallel printer communication. The HP-7470A graphics plotter and the HP-3438A digital multimeter were used to develop the routines for the IEEE-488 interface.<>