Keyboard controller (computing) (original) (raw)

In computing, a keyboard controller is a device that 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 arrives, the controller raises an interrupt (a keyboard interrupt) to allow the CPU to handle the input. Today the keyboard controller is either a unit inside a super I/O device or is missing, having the keyboard controller integrated in the USB keyboard itself, and its role in controlling the A20 line handled by the chipset.