What do you understand by scan codes, Computer Engineering

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.

Posted Date: 7/20/2013 2:42:30 AM | Location : United States







Related Discussions:- What do you understand by scan codes, Assignment Help, Ask Question on What do you understand by scan codes, Get Answer, Expert's Help, What do you understand by scan codes Discussions

Write discussion on What do you understand by scan codes
Your posts are moderated
Related Questions
Difference among the Static rams and dynamic rams. Static RAM: It is costly as each bit of memory will take around 6 CMOS transistors. More speedy as transistors are us

What are the Main aspects available in all word processors -  Ability to set page size and page orientation -  Ability to change font size and font style (for example Arial,

what is bitmap and pixmap

A program is backward compatible if it can use files from an older version of itself. For a file saved in the program to be backward compatible, it must be possible to open the fil

The subsequent step in Karnaugh map is to map truth table in the map. Mapping is done by putting a 1 in respective square belonging to 1 value in truth table. This mapped map is us

Define memory cycle time? It is the time delay needed between the initiations of two successive memory operations. Eg. The time among two successive read operations.

The enableEvents() method is used to enable an event for a certain object. Normally, an event is enabled when a listener is added to an object for a certain event. The enableEvents

Differences between internal and external treatment in boiler

Modus ponens rule: In fact the general format for the modus ponens rule is as follows: like if we have a true sentence that states the proposition A implies proposition B and

Through two block diagrams explain the difference between Space division and time division switching. Space and Time Switching: Space Switches: Connections can be made i