Debugging prototype board

Lorin Millsap · Post by **Lorin Millsap** » Thu Oct 15, 2020 4:13 pm

I figured it’s been a while since the last update. So I’m just letting you know where things are at. Kevin has sent me one of the prototype boards in the hopes that we can figure out why certain parts are not working.

Timing on the ROM and RAM is stable, the two VIA chips are also stable. There is some odd behavior on the banking latches, and the audio and video are not working.

We are certain it’s a timing issue and we will let you all know when that issue is resolved.

By sending me a proto board the hope is that we have a second set of eyes since trying to debug it over email and phone calls isn’t very productive.

picosecond · Post by **picosecond** » Thu Oct 15, 2020 5:06 pm

Have you considered enlisting help from the community? An independent design review couldn't hurt. All of the secret sauce is inside Vera so sharing the prototype board schematics seems pretty harmless. I know at least one person here makes a decent living on timing issues...

Lorin Millsap · Post by **Lorin Millsap** » Thu Oct 15, 2020 5:09 pm

Well actually the schematics for the time being are classified. I of course have a copy, but Kevin has asked me not to share them and I will abide that. I am still assembling the board and then I will apply fixes to known bugs. Then I can start checking things with the scope and also use some other tools to see what I can learn.

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StephenHorn · Post by **StephenHorn** » Thu Oct 15, 2020 5:39 pm

Thanks for the update, Lorin. It must be absolutely maddening for everyone on the team to be so close to launching the fundraiser for production, but for the bugs. Good luck!

Lorin Millsap · Post by **Lorin Millsap** » Thu Oct 15, 2020 5:51 pm

Indeed. In theory it should just work. But for some reason it isn’t.

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kelli217 · Post by **kelli217** » Thu Oct 15, 2020 8:06 pm

Weird question: Is the board itself more than two layers, and if so, is it possible that an inner layer has a discontinuity or a misrouted trace?

I'm just trying to think of something very basic that would nonetheless be difficult to track down.

Lorin Millsap · Post by **Lorin Millsap** » Thu Oct 15, 2020 8:37 pm

No possibility of that. Yes it is a multi layer board.

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Cyber · Post by **Cyber** » Fri Oct 16, 2020 6:17 am

9 hours ago, Lorin Millsap said:

Yes it is a multi layer board.

I think I remember somebody from team saying it will be two layer board so to make it more simple, cheaper and more understandable. Did this plan fail? Or am I remembering something wrong?

Lorin Millsap · Post by **Lorin Millsap** » Fri Oct 16, 2020 8:03 am

Sorry I guess I misunderstood the question then. It is a two layer board.

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SerErris · Post by **SerErris** » Fri Oct 16, 2020 12:44 pm

Multilayer >= 1 ?