Keyboard controller

Keyboard controller

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Questions and Answers

The following questions are asked to us quite frequently.
The associated answers should help you to obtain initial information at any time.
However, please do not hesitate to ask us further or additional questions directly.
We look forward to talking to you, face to face.

FAQ - Frequently Asked Questions


The key functions are programmed by us with a PC-programming device according to the assignment or array specified on the customer’s part. Afterwards, the program is verified in the same way.



No, this is not possible. You will receive a fully programmed and verified controller.



Yes, this can easily be realised by us, as soon as you send us the controller and the new specifications.



If no measures are taken during the interpretation of a keyboard matrix, only two simultaneously performed keystrokes can - for technical reasons - be analysed and sent to the PC. This is called 2-key-rollover. If 3 or more keys are pressed, the controller can't decide, which key exactly was activated. On the screen this effect is shown by so called "ghosts", signs whose key wasn't activated at all.

In order to evitate this problem, decoupling diodes can be put in the matrix of the keys. Such a prepared controller is called n-key-rollover-compliant, all keys can be analysed simultaneously. But not all key codes can be transmitted simultaneously to the PC because the protocols (PS/2,USB) don't support this. Alternatively to diodes, a special configuration of the matrix can allow a n-key-rollover, for example if "STRG" and "ALT" are connected separately, so that combinations made of 3 keys, for example "ALT" + "STRG"+ "ENTF", are possible even without diodes.



The controller repeatedly sends the code of the pressed key to the PC as long as the key remains pressed.


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