PCB

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ylp88

Senior Member
After a quick look: you should be connecting all of the PICAXE power pins to their respective rails - leg 8 of the 28X1 chip should be connected to 0V as well. You should be able to optimise the size and layout, but that's not that important...

ylp88
 
hippy

hippy

Ex-Staff (retired)
Download circuit looked okay to me.

I personally wouldn't connect D0-D3 of the LCD to 0V, I'd leave them floating.

I'd also add ...

100nF decoupling capacitors to the board. One near the 5V/0V inout, one each near the two chips, one across 5V/0V to LCD.

Diagnostic LED's + R's for Serial In, Serial Out and TX to FRM010.

Resonator for the 28X1.

You don't need to fit the capacitors, LED's nor the resonator but the ability is there if you need to or want to later.
 
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SilentScreamer

Senior Member
All the PICAXE power pins are connected aren't they?

I have no need to fit a resonator unless I want to overclock the chip don't I? (correct me if I'm wrong there) In which case this is my GCSE project so once its done its never going to be touched again.

Also what would the capacitors be used for? (sorry I only know what I've taught myself, my teacher at school only ever talk about 555 Timers and decade counters :(BORING:().

I'll clean up the layout once I've added everything else to the PIC
 
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bgrabowski

Senior Member
You have connected the reset switch wrongly. The switch has 4 legs but they are 2 pairs and switch across the shortest side. This part on your layout needs to be rotated through 90 degrees.

Some of your pads are quite thin and some are almost touching, I would suggest that you consider making all the squashed pads the same. A size of 0.1" x 0.07" with a 0.03" hole has proved the best option for my students' GCSE projects over the years.

You would produce a more practical finished product if the +V and 0V pads were much closer together. Also consider adding your name and if possible the project title in copper label.

Finally, double check that you do have the miniature preset that you have placed on your layout. The most commonly used type in schools is the next size up.
 
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SilentScreamer

Senior Member
Ahh thanks, ill make those changes in the morning. The preset is the correct size I am using some that I have purchased myself as my school only uses 100K.

All the pads are in the software's default setting, I'll be sure to change them to your suggested size.
 
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