Here, we have used PIC microcontrollers for interfacing with keyboard decoder. So before moving further, we will give a brief introduction to PIC Microcontrollers. PIC microcontrollers named as programmable interface controllers are electronic circuits which belong to a family of modified Harvard architecture prepared by microchip technology. They are widely used for embedded systems moreover there popularity is for low cost. Industrial developers and hobbyists widely use them for serial programming, reprogramming flash memory means, larger user base and for widespread collection of application notes.
Compatible Programming technique
For PIC, we use special simple software named as JDM programmer which is compatible to PIC microcontrollers. JDM programmer supports serial port and parallel port programmers. It does not require any external supply. Moreover, it helps in loading the source code into your microcontroller through simple software winpic800. It’s chosen as the best compatible microcontroller and JDM serial programmer. Additionally, it’s cheap and defined as the best alternative in the early stages. We strictly suggest do not use a laptop for JDM programmer. Users can easily purchase JDM programmers as they are very reasonable.
For converting data into serial output, we require a PC Keyboard decoder. Its main feature allow PC keyboard to decode the data into serial ASCII at 9600 bps output. They are relatively cheap and best used to a keyboard on a microcontroller with numerous keys available. Other features of decoder comprise of easy to use, all special keys (ALT, CLT, and SHIFT) are supported along with complete keyboard keys are decoded. It works on 5v supply and receives standard 9600 bps ASCII output.
Circuit Diagram of PC Keyboard Decoder:
Interfacing Serial Output Data:
Now, the output from board can be interfaced from board to USB or from board to MCU (UART interfacing- RX pin).
As discussed above, users can use a MAX232 IC when interface with PC’s serial port as it accepts serial outcome. For USB interfacing you can use any USB to TTL UART adapter plus can take power from USB itself.
Interfacing with Microcontroller :
Our main aim is to receive serial data, for which we use a decoder and AT89S52 RXD pin. Choose any microcontroller to interface say AT89S52 as it is widely used but can be 8051 MCU. The code generated is given further to PIC microcontroller with minor changes. Well, decoder works on 5 volt so data is directly connected to microcontroller RXD pin.
After discussing the complete detail, we leave the programming part to you.