SYSTEM OVERVIEW
The 8259A Programmable Interrupt Controller manages interrupts for an Inte1386 DX microprocessor system. Interrupts from as many as eight external sources are accepted by one 8259A; as many as 64 requests can be accommodated by cascading several 8259A chips. The 8259A resolves priority between active interrupts, then interrupts the proces- sor and passes a code to the processor to identify the interrupting source. Programmable features of the 8259A allow it to be used in a variety of ways to fit the interrupt require- ments of a particular system.
1.10 INTEL PROGRAMMABLE LOGIC DEVICES
Intel manufactures a line of high speed PLDs (Programmable Logic Devices) specifically designed for use with microprocessors such as the Intel386 DX. These devices called j.LPLDs (Microcomputer Programmable Logic Devices) include the 85C220 and the 85C508/85C509. Some of the design examples in this manual use these devices.
