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Intel 8255




It was later made (cloned) by many other manufacturers.

This chip is used to give the CPU access to programmable parallel I/O, and is similar to other such chips like the Motorola 6520 PIA (Peripheral Interface Adapter) the MOS Technology 6522 (Versatile Interface adapter) and the MOS Technology CIA (Complex interface Adapter]] all developed for the 6502 family. Other such chips are the 2655 Programmable Peripheral Interface from the Signetics 2650 family of microprocessors, the 6820 PIO (Peripheral I/O) from the Motorola 6800 family, the western digital WDC 65C21 , an enhanced 6520, and many others.

The 8255 is perhaps most well known for its use in the original IBM-PC 's Parallel Printer Port (now largely defunct and replaced by the USB standard, and considered a Legacy Port ).

However, most often the functionality the 8255 offered is now not implemented with the 8255 chip itself anymore, but is embedded in a larger VLSI chip as a sub function. The 8255 chip itself is still made, and is sometimes used together with a Micro Controller to expand its I/O capabilities.