8255 Programmable Peripheral Interface Introduction: 8085 microprocessor need the interface ICs to interface with the I/O devices. In this lecture we focus on 8255 a programmable peripheral interface. Features of 8255 40 pin IC. 24 I/O pins divided into 3 groups, Port-A, Port-B, and Port-C. Port C can be used as a single 8-bit port or in group of four bits for providing handshake signals for Port-A and Port-B. 8255 can operate in different modes i.e. BSR Mode, and I/O Mode BSR mode is used for controlling individual bits of port C in read/write operation, I/O Mode of Operations are : Mode-0, Mode-1, Mode-2 . Mode-0 is used when simple I/O activity is required on all three ports, Mode-1 is used for handshake mode for Gp-A and G-B ports with