- Intel 8255
The Intel 8255 (or i8255) Programmable
PeripheralInterface chip is a peripheral chip originally developed for the Intel 8085microprocessor, and as such is a member of a large array of such chips, known as the MCS-85 Family. This chip was later also used with the Intel 8086and its descendants.It was later made (cloned) by many other manufacturers. It is made in DIP40 and PLCC44 pins encapsulated versions.
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 2650family of microprocessors, the 6820 PIO ( Peripheral Input/Output) from the Motorola 6800 family, the Western Design Center WDC 65C21, an enhanced 6520, and many others.
The 8255 is used in
home computers such as SV-328and all MSX, but is perhaps best 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 controllerto expand its I/O capabilities.
* [http://drew.hickmans.net/8255.htm Complete Description about the Intel 8255 IC]
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