Explain keyboard interfacing to 8088 through 8279, Electrical Engineering

Assignment Help:

Explain keyboard interfacing to 8088 through 8279.

The 8279 is a programmable keyboard and display interfacing component which scans and encodes up to a 64-key keyboard and controls up to a sixteen-digit numerical display.

The keyboard interface has built in first-in first-out (FIFO) buffer which allows this store up to eight keystrokes before the microprocessor should retrieve a character. The display section controls up to sixteen numeric displays from an internal 16 X 8 RAM which stores the coded display information.

The keyboard section has eight lines that can be connected to eight columns of a keyboard, in addition two additional lines including shifting and CNTL/STB keys. The key pressed are automatically de-bounced and the keyboard can operate into two modes two as: key lock out or n-key rollover. When two keys in the two as key lock out mode are pressed concurrently, only first key is known. In the N-key roll over mode, simultaneous key are known and their codes are stored into the internal buffer.

Control Word: 000DDMMM - Mode set is command with an op-code of 000 and two fields programmed to choose the mode of operation for the 8279. The DD field chooses the mode of operation for the display and the MMM field decides the mode of operation for the keyboard.  

2055_The 8279 control word summary.png

The 8279 control word summary


Related Discussions:- Explain keyboard interfacing to 8088 through 8279

Cathode-ray tube, Q. Explain Cathode-ray tube? While the CRT display is...

Q. Explain Cathode-ray tube? While the CRT display is one of the oldest, it still remains one of the most popular display technologies. The raster-scanned display devices work

Find the bandwidth of the modulated signal, The signal m(t), whose frequenc...

The signal m(t), whose frequency spectrum M(f ) is to be transmitted from one station to another. Let the signal be nor- malized, i.e., -1 ≤ m(t) ≤ 1. Find the bandwidth of the mod

Pdc, disadvantages of shunt clippers

disadvantages of shunt clippers

State the advantages of expert systems, State the Advantages of expert syst...

State the Advantages of expert systems -  Never "forgets" to ask a question in determining the logic -  provides consistent answers - Less skilled work force needed, ther

Why digital signal processing require specialized hardware, Why does digita...

Why does digital signal processing require specialized hardware? A) It needs to perform analog as well as digital functions. B) General-purpose microprocessors cannot perfor

What is capacitor, What is Capacitor -  A capacitor is an electrical d...

What is Capacitor -  A capacitor is an electrical device that is used to kept electrical energy.   -  The unit of capacitance is Farad. The symbol of capacitance is C.

Synchronous and asynchronous serial communication, Differentiate between sy...

Differentiate between synchronous and asynchronous types of serial communication.   Serial data communication uses two fundamental types as, synchronous and asynchronous. With

What do you mean by dearness allowance, Q. What do you mean by Dearness All...

Q. What do you mean by Dearness Allowance? Ans: Dearness Allowance is in the type of compensation for Established increase in the cost of living and comprised of Dearness All

Draw and explain an rc integrator, Q. Draw and explain an RC integrator .De...

Q. Draw and explain an RC integrator .Derive the relation between input  and output voltage. Solution: A circuit in which the output voltage is directly proportional  to the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd