Programmable Peripheral Interface:

8255 is a general purpose programmable peripheral parallel I/O device manufactured by Intel and this is compatible with any microprocessor. It contains three programmable ports including one port for bi-directional data transfer.

Data Bus Buffer

This three-state bi-directional 8-bit buffer is utilized to interface the 8255 to the system data bus. Data is received or transmitted by the buffer upon execution of output and input instructions by the CPU. Status information and Control words are also transferred from the data bus buffer.