What do you understand by scan codes, Computer Engineering

Assignment Help:

Q. What do you understand by Scan Codes?

A scan code is a code produced by a microprocessor in keyboard when a key is pressed and is unique to key struck. When this code is received by computer it reports an interrupt and looks up scan code table in BIOS and realize which keys have been pressed and in what combination. Special memory locations known as status bytes tell the status of locking and toggle keys for example Caps lock etc. Every key press produces two different scan codes - one on key-push down known as Make code and another on its popping back known as Break code. This two-key scheme enables the computer to tell when a key is held pressed down for example ALT key when pressing another key say CTRL-ALT-DEL.


Related Discussions:- What do you understand by scan codes

calculates the area and perimeter of a rectangle, Write a program, using f...

Write a program, using functions, that calculates the area and perimeter of a rectangle whose dimensions (Length & width) are given by a user.

What is simd, What is SIMD? Single Instruction stream, Multiple Data st...

What is SIMD? Single Instruction stream, Multiple Data stream (SIMD) shows an organization that contains many processing units under the supervision of a common control unit. A

What are the main functions of sound cards, Q. What are the main functions ...

Q. What are the main functions of sound cards? Sound card (The card is frequently directly built into motherboards these days) is a board that has digital to analog sound conve

State disadvantages of object oriented analysis design, State Disadvantages...

State Disadvantages of object oriented analysis design You know that OO methods only create functional models within objects. There is no place in methodology to design a compl

Advantage of crc over simple checksum, Why can CRC detect more errors than ...

Why can CRC detect more errors than simple Checksum? There are two purposes a CRC can identify more errors than a simple Checksum. 1. Since an input bit is shifted by all th

Evaluate speed of disk drive, Q. Evaluate Speed of disk drive? Drive S...

Q. Evaluate Speed of disk drive? Drive Speed: Amount of information which can be transferred in or out of memory in a second is called as disk drive speed or data transfer ra

Why is xml such an important development, It takes away two constraints whi...

It takes away two constraints which were holding back Web developments: 1. Dependence on a one, inflexible document type (HTML) which was being much abused for tasks it was neve

Subtraction using 2's complement method of binary number, Subtraction of 00...

Subtraction of 0011.1001 - 0001.1110 using 2's complement method Ans. Firstly 1's complement of 0001.1110 is 1110.0001 and 2's complement is 1110.0010. If a last carry

Explain main requirements satisfy by page replacement policy, List out the ...

List out the main requirements between page replacement policies which should be satisfied by a page replacement policy? The major requirements that should be satisfied

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