PS/2 Keyboard Interface

Current Part:

PIC 18F452 Microcontroller
7805 +5v Regulator
10kΩ Resistor
7x 330 Resistor
20 MHz
47uF Capacitor
PS/2 Port
PS/2 Keyboard
9v Connector
Battery Holder

Parts List Details
           If you have read any of my previous articles then some of the parts seen above should be familiar. If not, do not worry because I'll give a little more detail on the most important parts below.

PIC 18F452
           This microcontroller will serve as the central processor for input and output of our example system. The input will be coming from the PS/2 keyboard, translated and then the microcontroller will output the keypress to a 7-segment LED display.

7805 +5 Voltage Regulator
           This is a standard +5v regulator that I use all over the place. It's a quick and simple way to bring any voltage above +7.5v to a steady +5v which is what our digital electronics want to see.

20 MHz Crystal
           The PIC will be operating at this clock frequency (20 MHz). The ps/2 keyboard clock rate output to the pic will be around 20-30 KHz, which doesn't give us much processing time between PS/2 clock cycles, so the faster crystal here, the better.

PICkit 2
           The PICkit 2 is a great programmer for uploading your compiled code from your PC to the PIC. It comes in a USB package so you don't have to worry about needing a serial or parallel port on an old desktop.

PS/2 Port
           This is a surface mount PS/2 connection port, so you will have to solder some wires onto it or make your own breakout board. I soldered a wire onto each pin so I could connect the port to my breadboard.

7 Segment LED
           The keypress will show up on this 7 segment display after the PIC is done processing the input. Not all characters can fit on the display like W or K, so those were omitted, but the majority of numbers and letters show up on a 7 segment display just fine.

Jumper Wires & Breadboard
           Additional breadboard wires, a breadboard, some batteries and connectors are also used for the platform setup an power supply.