Let's Make Robots!

Chip-tuning your Picaxe 28 board in a snappy way

Sometimes you want to be able to go at different speeds, usually to make serial connections. Here is a snap on / off way of setting it up

Update: Note that the newer Picaxe models can change a lot by commands like setfreq alone :)


This is only for dummies like myself using Picaxe 28Xx standard board. However, the thinking may also apply to those making their own boards.

Specially if you are doing serial communication to say a LCD display, an Easy Radio module, a dedicated sound chip, your PC or something else.. you may need to change the clock speed with an external resonator.

Resonators cannot be found in my local electronics shop, but they are dirt cheap in the Picaxe shop, so I bought a handfull some time ago - in different speeds. I can recomend that!

Then - if you are using the standard board, you will have to de-solder the resonator on the board.

Instead of just soldering on the alternative resonator, I solder on 3 pins like this:


.. and as you can see on the main picture on this post, I stick them resonators into thingeys, so they can just be interchanged :)

It does not matter which way they turn!

See the basic command setfreq in your manual!

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Captain Tuna has it in one. It is that simple. Cheers

Where do you purchase the plug things you solder the resonator to? I've only ever seen them on servo leads, but I can think of endless uses.
Any electronics store, they are quite standard thingeys!
Apparently not in New Zealand... I may have to order in some from a U.S. online store or something. I get most of my parts from www.jaycar.co.nz, www.globalpc.co.nz, www.sicom.co.nz, and on rare occasions www.dse.co.nz. I don't think any of them stock them.
From Jaycar : http://www.jaycar.co.nz/productView.asp?ID=HM3403  maybe as close as they have.
Yeah, I use those. They're incredibly bulky though.
Might check radio control stores, where they sell model airplanes and cars. They should stock servo connectors for HiTec that would match very close to what Frits has.
Thanks, I know of a store, I'll have a look.

Good tip Fritz! That's one modification of the board I'm definately going to do.

Also: it took me a while to figure out that you do need that setfreq command. Otherwise the external resonator will simply be ignored. 

maybe this way : http://www.lasertag.de/pics/circuit1.gif (check ports 4 and 5) but i'm not sure.