Intel 8255 (or i8255) Programmable Peripheral Interface

• The Intel 8255 is an intelligent programmable peripheral interface (PPI)ii
• It is a multiport input/output device
• It is a general purpose device for interfacing parallel I/O device to microprocessor/microcontroller bus
• Some manufactures use the term 'peripheral interface adapter'
• The main function of 8255 PPI ae to interface peripheral devices to microcomputer system
• It is a 40-pin DIP IC
• It operated on a single +5v dc supply
• It gas three 8-bit I/O ports, namely, Port A, Port B, & Port C
• Port C is further divided into two 4-bit ports-Port C upper & Port C lower
• Total 4-Ports are available, two 8-bit ports & two 4-bit Ports 
• Each port can be programmed as an input port or an output port 
• It has an 8-bit internal register to store the control word. the control word is used to configure the three ports of 8255 either as input or as output