My Microchip PIC prototype tester board.


I first came across the Microchip range of controllers after seeing a project on robotbuilder.co.uk by Nigel Goodwin. After downloading Nigel's excellent Pic Programmer and purchasing a couple of 16F84 chips from the local electronics shop, I downloaded the MPLAB IDE from Microchip.com. I then realised, to get to grip's with the Pic programming language, I needed some sort of test circuit. Maplins sell one on their site, but at 29, it isn't exactly a cheap way to see the results of your programming efforts.

I'm not skint or tight, but why buy when half the fun is actually producing the things yourself.

The circuit below is very easy to build. Mine is on a 20 x 20 hole piece of copper strip board.

As you will see in the circuit diagram, there are two 'press to connect' switches, for input purposes, four Led's, for output indication, (2 red, 2 green, why not ?), and an LCD character display. The display in my original circuit is a 1 x 16 out of a telephone / fax / copier I had given to me that didn't work, so I salvaged what I could. The display works in four-bit mode. This reduces the number of output lines used on the Pic.

Two Adobe pdf files on Hitachi based display control are here, pdf1 , and here, pdf2 . These and many more useful files can be downloaded from the Everyday Practical Electronics website.

My Pic test board

R1-R4 10K ohm
R5-R8 470 ohm
R9 10K pot
C1+C2 10nF
D1-D4 Led's, any colour :)
X1 4Mhz Crystal

The circuit gives a good range of scope for learning the Pic language, e.g.
Flash an led,
Knight Rider effect,
Knight Rider effect reversed if button x pressed,
Display text,
Change text when button x pressed,
Scroll text left, right on button x pressed
The list is endless using such a simple circuit, the coding is up to you.
I won't include example code here, but if you need help, feel free to e-mail me.

A Zif (Zero Insertion Force) socket is advised on the tester board instead of a normal 18 pin dil socket. There's less chance of breaking the Pic's little legs. (More info to follow)

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