Keyboard controller (computing)

For other uses, see Keyboard controller.

In computing, a keyboard controller is a device which interfaces a keyboard to a computer. Its main function is to inform the computer when a key is pressed or released. When data from the keyboard arrive, the controller raises an interrupt (a keyboard interrupt) to allow the CPU to handle the input.

If a keyboard is a separate peripheral device wired to the system unit (such as in most modern desktop computers), then keyboard controller is not actually attached to keys' circuits, but receive scancodes from a microcontroller embedded to keyboard via some kind of serial interface. In this case the controller also should control keyboard's LEDs by sending data back to keyboard through the wire.

Early PCs used Intel 8042 chip to interface to the keyboard. In computers with a PS/2 connector the keyboard controller is integrated with mouse controller.

See also

• Keyboard buffer
• AT keyboard
• KVM extender

External links

• keyboard controller - Computer Dictionary
• keyboard interrupt - Computer Dictionary
• Keyboard controller at ComputerHope.com
• KBD43W13 Keyboard and PS/2 Mouse Controller