Driver IO Rev B Review

[ryanbear22]

Tracking any changes for Rev B here

[ryanbear22]

if you go under Tools > Design Rule Check > Run Design Rule Check you'll see there's a lot of errors relating the clearance. Try editing the rules under Design > Rules to resolve these errors. Looks like most of the errors have to do with rules that can be changed under Design -> Rule Wizard. Might be worth comparing the Rev A rules

[ryanbear22]

remove any acute angled traces

[ryanbear22]

acute here too

[lmaddox28]

These LEDs and headers need to be labeled on the silkscreen. What does the LED indicate? What does each connector pin connect to?

[lmaddox28]

A bit tight right here on U1 & R13. You can see that the R13 silkscreen is a bit too close, and the U1 silkscreen is not very close to the actual component. I would re-route according to the blue annotations in this screenshot and try to move U1 to the top left hand corner. I may add more on this ADC layout in another comment.

Also, C1 & C2 are overlapping. Their dark-green cutouts should have their own space.

[lmaddox28]

P10 silkscreen is off of the PCB:

[lmaddox28]

This RPi silkscreen outline has a plethora of violations--including being off the board:. I would look at what Rev A did here (either it was deleted or modified):

[lmaddox28]

These headers are pretty close. If we are attaching alligator clips to them, we will be in danger of shorting GND & power, or power line to power line. The more relief we can add between these, the better:

[lmaddox28]

All of the connectors need to have text labels describing what they connect to. See Main IO for reference:

[ryanbear22]

This RPi silkscreen outline has a plethora of violations--including being off the board:. I would look at what Rev A did here (either it was deleted or modified):

was a second outline added to resolve this? (Rev A)

[lmaddox28]

I would change all of the silkscreen labels to 7.5mil stroke width. 30 mil text height should be enough to be legible, but if we go that small we want to decrease the width for clarity. See the difference below, where R32 has been changed to 7.5 mil. This change can be done fairly easy--as seen below, right click on one of them & then select "Find Similar Objects" and select "Same" for Text Height & Text Width. Apply --> Ok & then change them to 7.5mil in the properties panel that pops up.

[lmaddox28]

One thing we want to keep in mind if our ADC signals have poor resolution is to add in a voltage reference to the circuit. It doesn't seem like we are utilizing it right now. Unfortunately this isn't something we can test until we get the actual signal. We should probably add the voltage reference to this revision so the PCB has the pads for it in case we want it. We don't want this to be the only thing that makes us order a Rev C.

[lmaddox28]

It is unclear to me why we would give ourselves the option to attach 3.3V power and the I2C lines to the analog inputs, and I couldn't find any clarification on Confluence. Lets get an answer to this question before ordering

[lmaddox28]

A couple things on the ADC layout: (1) It would be nice to space things out a bit so that the components are easier to populate. (2) as Cooper mentioned, with a ton of capacitors and resistors next to each other, its nice for the capacitors to be orientated vertically and the resistors horizontally--with this circuit, there is a large mix of it:

[lmaddox28]

To decongest the bottom part of the PCB and allow for the headers to be spaced out more (along with the other circuits), I would recommend moving either the headers or the UART transceiver to the space up here.

[lmaddox28]

Related to the comment above: you can just move everything up a little bit, since there is empty space above too.

[lmaddox28]

If you swapped the regulator & the INA chip, you would not have these bottom layer traces having to do a U shaped path to get to the RPi.

[lmaddox28]

C36 should be in line with C33, C34, C35. Together they should be as close to the ICs Vin pin as possible. This means, move R60 down and turn it horizontal to allow for the caps to get as close as possible. This was, the input into the chip is as filtered as possible (bypass caps should also be as close as possible to the Vin pin).

[lmaddox28]

This isn't mission critical, but another best practice to ensure that population goes as planned. Put the IC silkscreen labels in the same corner and orientation as the IC is. That way, there is no confusion as to which way the chip goes. I've marked some examples here, but it applies to all of them:

[lmaddox28]

Recall what Cooper said about the Kevlin Connections for the shunt resistors. For the 12V, notice that the pad being used for PresShunt12V is the pad on the fuse, not the resistor. This will result in a poor reading:

For the 5V resistor, the pad being probed is from L3, not R49:

[lmaddox28]

Before trying to rearrange entire circuits, I would recommend routing these DIO signals orthogonally. This will free up a lot of room to work with--you won't have to maneuver around these diagonals.