PCBs

Common Errors

Expand each point for more detailed information.

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.

Standard CAN connector pinout

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

Example of daisy chaining

Instead, prefer having traces not broken by pads.

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.

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.

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

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

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.

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.

See also: PCB Design

Other Things to Look Out For

  • Is everything on the silkscreen layer within the bounds of the board?

  • Make sure there’s an edge.cuts layer.

  • Connector choices: are they reasonable?

  • Footprints and pinout: check them for every IC and make sure that they are correct.

  • Are the decoupling caps actually next to the IC?