Draw and elucidate the block diagram 8259, Computer Engineering

Draw and elucidate the block diagram of programmable interrupt controller 8259.

The 8259A adds 8 vectored priority encoded interrupts to microprocessor. It can be expanded to 64 interrupt requests by employing one master 8259A and 8 slave units. CS and WR should be decoded. Other connections are direct to microprocessor. 

Pins D7 - D0: bidirectional data connection, IR7 - IR0: Interrupt request, used to request an interrupt and connect to a slave in a system with multiple 8259A.

WR :-Connects to a write strobe signal (upper or lower in a 16 bit system) ,  RD :- Connects to IORC signal ,  INT :- Connects to INTR pin on the microprocessor from master and is connected to a IR pin on a slave  and  INTA :- Connects to INTA pin on the microprocessor.  In a system only master INTA signal is connected A0:- Selects different command words with in 8259A, CS: - Chip select - enables 8259A for control andprogramming, SP/EN: - Slave Program (1 for master, 0 for slave)/Enable Buffer (controls data bus transceivers in a large microprocessor based system when in buffered mode) and CAS2-CAS0:- Used as outputs from master to the slaves in cascaded systems. 

 

2345_micro.png

Posted Date: 8/20/2013 2:35:02 AM | Location : United States







Related Discussions:- Draw and elucidate the block diagram 8259, Assignment Help, Ask Question on Draw and elucidate the block diagram 8259, Get Answer, Expert's Help, Draw and elucidate the block diagram 8259 Discussions

Write discussion on Draw and elucidate the block diagram 8259
Your posts are moderated
Related Questions
Explain the term - Instruction execution We  know  that  the  fundamental  function  performed  by  a  computer  is  the  execution  of  program. The program that is to be exec


One of the most important competitive strategies for E-Businesses today is business process reengineering. BPR is more than automating business processes to make modest improvement

Q. What about division and multiply operations? In most of the older computers divisions and multiply were implemented using subtract/add and shift micro-operations. If a digit

This boils down to the concept of Binary digits. Take an array size of 64 for example. We begin from 0 and end at 63. We need 6 bits.But, if we were to begin from 1 and end at 64,

Reset and Submit are special types of input buttons. Submit is used to send data to the server and Reset resets/clears the form.

Q. Set up to Use parallel virtual machine? PVM employs two environment variables when starting and running. Each and every PVM user needs to set these two variables to employ P

Mathematical Simulation and Modeling Applications The tasks including modeling and mathematical simulation require a lot of parallel processing. Three basic formalisms in model

Explain DOS function call with one illustration DOS function call In order to use DOS function calls, always place function number into register AH and load all other re

Objectives After studying this unit you should be able to: 1. list various types of reprographic methods, 2. describe uses of various kinds of typewriters, 3. explain