8259

The Intel 8259 is a programmable interrupt controller (PIC) designed for the Intel 8080 and Intel 8085 microprocessors. The initial part was the 8259; the later 8259A was upward compatible and usable with the 8086 or 8088 processor. The 8259 combines multiple interrupt input sources into a single interrupt output to the host microprocessor, extending the interrupt levels available in a system beyond the one or two levels found on the processor chip. The 8259A was the interrupt controller for the ISA bus in the original IBM PC and IBM PC AT.