This article will describe and show you an example of how to create a system capable of interacting with a keyboard in order to understand what keys have been pressed. The example system will be built on a breadboard using a PIC microcontroller to communicate with the keyboard and display output.
Purpose & Overview of this project
The main goal here is to create a system that is capable of communicating with PS/2 devices, specifically the PS/2 keyboard. The PIC microcontroller will be connected to a PS/2 keyboard and it will receive keypress commands. Whenever a keypress is detected the PIC should output onto a 7-segment LED display which key was pressed.
Since PS/2 is a serial communication protocol and the PS/2 keyboard controls the clock signal we will need to use the PIC's capture module interrupt to detect falling edges (ps/2 data is valid on falling edges). Additionally, some constant values will need to be progammed in to represent letters and numbers to display onto the 7-segment LED output display.