Author Topic: FV-1 Board layout requirements/tips  (Read 373 times)

patrick398

FV-1 Board layout requirements/tips
« on: April 13, 2020, 11:28:21 AM »
Whilst i'm waiting for parts to arrive and before i begin my journey down this rabbit hole i thought i'd knock together a PCB for an FV-1 circuit. I copied one of the schematics from a Pedal PCB build doc, 3 pots, rotary, mix, and volume.

I haven't really done anything digital (unless PT2399 counts) so wondering if there are any layout requirements or things i should be aware of. Things like placement of critical components, certain traces to keep away from certain areas etc. The bottom pour on this board is for GND. I have digital GND traces for the FV-1 and EEPROM which go to a DGND pad which will be jumpered to the supply ground pad.
Given that i design faceplates before the PCBs i am pretty constrained by where the pots go, i always find myself having to work round them. After a few attempts i managed to route it without any ridiculously long traces but i'm sure it's far from ideal.

Any pointers would be greatly appreciated






Thanks!

vigilante397

Re: FV-1 Board layout requirements/tips
« Reply #1 on: April 13, 2020, 12:59:54 PM »
1 - Keep the crystal as close to the FV-1 clock pins as possible, you want the traces of the clock to be short.

2 - Ground pour/plane is a good idea

3 - Couldn't hurt to have test points here and there to make probing easier during debugging

4 - Have fun :) The FV-1 is super great!
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ElectricDruid

Re: FV-1 Board layout requirements/tips
« Reply #2 on: April 13, 2020, 05:58:25 PM »
+1 what Nathan said.

The sensitive bits generally would be the clock and the SPI comms. You'd keep them as short as you can, and you'd try to keep analog traces away from those high speed digital traces.

However, in the FV-1 the clock is pretty slow, so it shouldn't be too bad. Similarly, the FV-1 runs the SPI at a pretty slow rate (100s of KHz, not MHz). So it shouldn't fuss too much. Ground plane is always a good idea.


patrick398

Re: FV-1 Board layout requirements/tips
« Reply #3 on: April 15, 2020, 05:06:50 AM »
Thanks guys, good place to start. Hopefully i'll know more when the boards arrive and they do/don't work properly. Been looking into the 4049 method of over/under clocking the fv-1 which looks interesting. I'll save that for once i've got my tiny mind round the basics though

cheers

Ice-9

Re: FV-1 Board layout requirements/tips
« Reply #4 on: April 17, 2020, 07:33:36 AM »
I see some traces running between the FV-1 pins I would try and re route these especially as you have the audio output trace running directly between the input pin. Also check some of your trace clearances around the pots, they look like they are running very close to the pot pins.
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deadastronaut

Re: FV-1 Board layout requirements/tips
« Reply #5 on: April 17, 2020, 08:03:15 AM »
following, i have a fv1 working on breadboard at the mo.....but awaiting a pickit2.  :icon_rolleyes:
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patrick398

Re: FV-1 Board layout requirements/tips
« Reply #6 on: April 17, 2020, 05:28:59 PM »
I see some traces running between the FV-1 pins I would try and re route these especially as you have the audio output trace running directly between the input pin. Also check some of your trace clearances around the pots, they look like they are running very close to the pot pins.

Thanks for the tips, i was wondering specifically about these sorts of traces, best to avoid interference. As for clearance, everything checks out on DRC and it doesn't look out of the ordinary to me, clearly the fab house can handle it :)

ElectricDruid

Re: FV-1 Board layout requirements/tips
« Reply #7 on: April 17, 2020, 05:36:54 PM »
"fab house can handle it" is kind of a *minimum* requirement these days. They can produce stuff that I'd never want to solder.

patrick398

Re: FV-1 Board layout requirements/tips
« Reply #8 on: April 17, 2020, 06:19:27 PM »
"fab house can handle it" is kind of a *minimum* requirement these days. They can produce stuff that I'd never want to solder.

Yeah, the kind of spacing that makes you feel like you're trying to thread a needle with boxing gloves on