UPD8255

NEe Microcomputers, Inc. NE'C fLPD8255 fLPD8255A·5 PROGRAMMABLE PERIPHERAL INTERFACES D ESCR I PTI ON The IlPD8255 and IlPD8255A-5 are general purpose programmable INPUT/OUTPUT devices designed for use with the 8080A/8085A microprocessors. Twenty-four (24) I/O lines may be programmed in two groups of twelve (group I and group II) and used in three modes of operation. In the Basic mode, (MODE 0), each group of twelve I/O pins may be programmed in sets of 4 to be iniJut or output. In the Strobed mode, (MODE 1), each group may be programmed to have 8 lines of input or output. Three of the remaining four pins in each group are used for handshaking strobes and interrupt control signals. The Bidirectional Bus mode, (MODE 2), uses the 8 lines of Port A for a bidirectional bus, and five lines from Port C for bus control signals. The IlPD8255 and IlPD8255A-5 are packaged in 40 pin plastic dual-in-line packages. F EATU RES Fully Compatible with the 8080A/8085 Microprocessor Families ...