The Z80181 SAC TM Smart Access Controller (hereinafter, referred to as Z181 SAC) is a sophisticated 8-bit CMOS microprocessor that combines a Z180-compatible MPU (Z181 MPU), one channel of Z85C30 Serial Communication Controller (SCC), a Z80 CTC, two 8-bit general-purpose parallel ports, and two chip select signals, into a single 100-pin Quad Flat Pack (QFP) package (Figures 1 and 2). Created using Zilog's patented SuperintegrationTM methodology of combining proprietary IC cores and cells, this high-end intelligent peripheral controller is well-suited for a broad range of intelligent communication control applications such as terminals, printers, modems, and slave communication processors for 8-, 16- and 32- bit MPU based systems.