Explain the 8259 microprocessor, Electrical Engineering

Explain the 8259 microprocessor.


The 8259A adds 8 vectored priority encoded interrupts to the microprocessor. This can be expanded to 64 interrupt requests with using one master 8259A and 8 slave units. CS and WR should be decoded. Other connections are direct to microprocessor.  The workings of pins are given here:

Pins D7 to D0: bidirectional data connection pins,

IR7 to IR0: Interrupt request, utilized to request an interrupt and connect to a slave in a system along with multiple 8259A.

WR: It connects to a write strobe signal (upper or lower in a 16 bit system) , 

RD: It connects to the IORC signal, 

INT: it Connects to the INTR pin on the microprocessor by the master and it is connected to a IR pin on a slave and 

INTA: It connects to the INTA pin on the microprocessor.  Within a system only the master INTA signal is associated

A0: it selects different command words along with in the 8259A,

CS: Chip select - It enables the 8259A for programming and control, 

SP/EN: Slave Program (that is 1 for master, 0 for slave)/Enable Buffer (as controls the data bus transceivers into a large microprocessor based system while in buffered mode) and 

CAS2-CAS0: It used as outputs from the master to the slaves in cascaded systems.


Figure: 8259 Block Diagram

Posted Date: 5/25/2013 3:44:59 AM | Location : United States

Related Discussions:- Explain the 8259 microprocessor, Assignment Help, Ask Question on Explain the 8259 microprocessor, Get Answer, Expert's Help, Explain the 8259 microprocessor Discussions

Write discussion on Explain the 8259 microprocessor
Your posts are moderated
Related Questions

The manufacturer of a 6V dry-cell flashlight battery says that the battery will deliver 15 mA for 60 continuous hours. During that time the voltage will drop from 6V to 4V. Assume

Q. Explain working of three-phase transformers? Transformation in three-phase systems can be accomplished in either of two ways: (1) connecting three identical single-phase tra

Risers: Riser Design : A riser or a feeder head is a passage of sand made in the cope to permit the molten metal to rise above the highest point in the casting after the mou

Compute the efficiency of the transformer of Example corresponding to (a) full load, 0.8 power factor lagging, and (b) one-half load, 0.6 power factor lagging, given that the input

Q. The voltage at terminal a relative to terminal b of an electric component is v(t) = 20 cos 120πt V. A current i(t) =-4 sin 120πt A ?ows into terminal a. From time t 1 to t 2 ,

Explain Diffusion. Diffusion : Though, the mobility of the carriers in a semiconductor is greater than the electrons in metals, the conductivity in the former is much less t

Example Memory to  Registers Example: Write  assembly  language  statement  to copy  data byte  36H  stored  at 2025 H  to register B. Solution : Assuming 2025 H is sto