PCBs

We should try to fix as many errors it flags as possible. If DRC is complaining about things that are intended, make a note of that in your PR.

CAN connector pinouts should match this image. The yellow line is the edge of the board and the connector is mounted on the front in this case.

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Standard CAN connector pinout

If the pad on R2 gets damaged, R1 and R3 are no longer connected which makes losing functionality more likely.

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Example of daisy chaining

Instead, prefer having traces not broken by pads.

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Preferred routing that avoids daisy-chaining

I’ve just placed a GND fill, which means that the GND pads should be connected, but there is still a rats nest showing them as unconnected. This is because I have not re-filled the zones (b), which you should get in the habit of doing as often as you save.

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Out-of-date fill

After filling you can see the rats nest has disappeared, but nothing else has changed in this viewing mode (which doesn’t show fills) which makes it hard to notice.

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After being re-filled (b).

The thing to avoid here is prematurely routing the GNDs that the rats nest shows as disconnected. This looks fine…

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Don’t trace what should be a fill!

But you’re really just routing over a fill and cluttering up your schematic / preventing other traces from using that space.

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Extraneous trace overlaps the fill.

Additionally: Try not to route on one side of the board what is a fill on the other. For example here I’ve moved the GND fill to the back. Rather than having one big trace and a via, use multiple shorter traces each with their own via.

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Routing components to the back fill using multiple short traces and vias.

Remember that we need to get tweezers and a soldering iron to all of the pads when assembling boards. Most of our boards aren’t super space constrained, the further components are from each other the easier assembly will be.

In order of importance, keep silkscreens off of

• Pads

• Other silkscreens

• Vias

We try to stick to M3 for all electrical mounting.

This makes assembly much easier for our non-space-constrained boards.