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Friday, 22 July 2011

PIC 'n' Choose how to Count

Well, I've been fiddling with some PICs today, most notably the 16F628A. I bought the chip and a nice LCD display on ebay quite some time ago with the intention of building a good quality bench frequency counter.

So, to cut a long story short, another project is born. I've thrown together an initial prototype, but as is normally the case, this has raised a few questions.

Firstly, how do I align the PIC clock to be exactly accurate? With a frequency counter perhaps? Recursion - see recursion.

Then once I've done that how do I calibrate the counter? Here I would need one of those oven baked OXO thingumabobs. There's quite a few of them on ebay but they all seem to be in China; not sure I want to wait for a delivery from China.

So threes the basic board; there isn't much to it except a small RF amplifier and the PSU for the electronics, oh and the PIC itself of course.

The first thing I realised when I started to do this was that my PIC Programmer was in fact obsolete! Can you believe it; it wouldn't program these new fangled chips, so I trundled to a new local Maplin store and came away with a PIC programmer in kit form:

That took just over an hour to build. It also includes some I/O circuitry and other bits and bobs so it should come in handy in the future. The serial protocol doesn't seem to be compatible with MPASM from Microchip; so I'm having to use a non IDE which is a pain.

The display that I bought simply ages ago looks really neat when its being used:
It is, however, close to impossible to take pictures of.

I have a feeling that this project is going to roll and roll...

The following pictures are here for two main reasons, firstly because I can, and secondly for my mum:

This is Chopsey cat asleep on my new suitcase:

 This is the Geddy cat asleep in my left arm:

And  this is Chopsey cat again, but this time he is stupidly chasing his tail (he does this lots):

Fun,. egh?

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