The HT82C55A is a high performance CMOS version ofthe industry standard 8255A and is manufactured using aself-aligned silicon gate CMOS process (Scaled SAJI IV). Itis a general purpose programmable I/O device which may beused with many different microprocessors. There are 24 I/Opins which may be individually programmed in 2 groups of12 and used in 3 major modes of operation. The highperformance and industry standard configuration of the82C55A make it compatible with the 80C86, 80C88 andother microprocessors. Static CMOS circuit design insures low operating power. TTLcompatibility over the full military temperature range and bushold circuitry eliminate the need for pull-up resistors