8255 PPI(Programmable Peripheral Interface) Microprocessor and Interfacing by Ravinder Nath Rajotiya - March 26, 2020April 21, 20220 8255 Programmable Peripheral Interface 8255 is a programmable peripheral interface IC which is used as an interface between the external device and the microprocessor for parallel communication. This IC is a 40-pi IC having three ports known as Port-A(PA), Port-B(PB) and Port-C(PC). these ports can operate in various modes. the complete details is given in the following PPTSs. Features of the 8255: It provide three I/O ports All the three I/O ports are latched Port operation is configurable by programming 8255 i.e. writing a control word in CWR BSR- bit set-reset mode allows individual pins of port C to be controlled to be set or reset. PIN diagram of 8255 8255 PPI is a 40-pin IC, it has three 8-bit ports named PA, PB
8255 Programmable Peripheral Interface Interfacing devices by Ravinder Nath Rajotiya - March 13, 2020May 10, 20210 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