GENERAL-PURPOSE DATA-ACQUISITION AND CONTROL VIA THE IBM PC CENTRONICS PRINTER PORT

This paper describes a novel system for acquiring data and controlling equipment via the parallel port of an IBM PC or compatible. An inexpe nsive circuit and associated computer software are described which all ow up to 256, eight-bit, digital input and output devices, together wi th eight hardware interrupt request lines, to be accessed via the Cent ronics parallel printer port. Programs can access the external devices via a software interrupt into a memory resident driver program. This allows all common programming languages to make use of the system. Dat a transfer speeds of over 40 000 reads/writes per second are achieved.