I'm kind of new to electronic/PCB work... I'm noticing on mostly all other repositories you have you advertise the overcharge + static charge protection, could this feature be added to this PCB?

EDIT: "other repositories" refer to your keyboard projects such as the Voyager series

It looks like the fuses rely on the gnd and vcc pins from the usb power (micro/C), so could this be added on a keyboard PCB file from the JST port?

👋

First off thanks to all for making this open source!

Tldr' - When opening the PCB file in KiCad, I get the following error.

The weird thing is I have the latest version, 5.1.5 at the time of this writing.

======

Decided to start learning about PCB design; wanted to prototype something using a daughter board, came across this, looks perfect as is. Since I have 0 skill in SMD soldering nor the tooling I was hoping to get the fab house to assemble everything with parts. JLCPCB seems like the place to do it since they'll read everything off the gerber file and offer the service.

The issue is that for the assembly service, the project needs to be at a minimum 20x20 so I just wanted to tweak the edge cuts just a bit.

I cloned with --recursive so I believe I got everything, is there possibly something I'm still missing?

Also open to alternate places that could do the work, just looking at JLCPCB cause I've heard of em and they the easier interface to deal with.

Thanks so much 🎉

There isn't usb-c connector (TYPE-C-31-M-12) in the position file.
https://github.com/ai03-2725/Unified-Daughterboard/blob/master/Production/C3/Position/Unified-Daughterboard-all.pos
Would you tell me the position of usb-c connector ?

In reviewing the design of the Unified Daughterboard I found some room for improvements in future iterations of the design:

• A bidirectional TVS is not ideal across the 5V rail, because it will permit a negative transient on VCC (such that VCC sees a negative voltage below GND). Better protection would be provided with a unidirectional TVS, as it would prevent VCC from being forced below GND.
• The TVS in the BOM provides a min breakdown of 10V and a reverse standoff of 9V. This seems unnecessarily high for a 5V line.
• Instead of having a discrete TVS, it seems like it would be optimal to make use of the existing ESD component on the board. It provides four channels of ESD protection, and there is no need for redundant ESD protection on the data lines. Recommend removing two of the redundant channels from the ESD I/O lines and using one of those channels to protect VCC instead. For an similar example of how this looks, see the datasheet for USBLC6-2SC6.
• Ferrites are designed to filter out EMI in the >10MHz range. The intended use of a ferrite to restrict ESD currents will not be very effective, because the 8/20us ESD transient exists more in the 100kHz range where ferrites are still low impedance. Instead of using a ferrite for ESD purposes, it would be more effective for EMI purposes, by placing it between USB-C shield and USB-C GND connections, so as to provide higher impedance to the USB cable shield connection.
• For metal keyboard cases (which are inherently susceptible to ESD discharges during normal use), there isn't really a great place to dissipate the discharge because USB devices typically don't have a direct path to earth ground (due to isolated power supplies upstream). Given that, that best option is simply shunt the discharge currents to the local ground, which will (harmlessly) cause the entire circuit potential to shift together during the transient. I mention this because it seems emphasized that the metal connection to case only goes through one mounting hole, which really doesn't benefit the circuit in any way. Whether it is tied to digital GND (or the USB shield) through one hole or four makes no difference.
• If you really wanted to keep only one hole as conductive to the case, it would be better to remove the copper plane on the back of the board on those corner (or at least have them match the annular ring on the front). When making a mechanical connection to a metal surface, soldermask is not a reliable insulator; there are no inherent voltage withstand guarantees (noting however that the IPC standards do acknowledge some presumed voltage withstand capability), and soldermask is far to easy too accidentally scrape off during fastening.
• The description states "when a voltge spike is detected, it shorts VCC and GND" which isn't quite accurate, in reality it just clamps the voltage (VCC or I/O line) to a safe level so as to prevent damage to other components.
• It looks like there are a few instances of via-in-pad; this is not ideal for manufacturing as solder gets pulled into the via (unless you do a nonconductive epoxy fill), so yield may go down (or cost will go up).
• A power trace on the back side immediately cuts underneath the data lines coming off the connector. Might be better for the USB signals if that trace were pushed up higher to be under the connector instead, giving a more consistent ground plane underneath. That said, I realize it will interfere with the star pattern in the copper, so...it may not be worthwhile?
• USB signal traces aren't really the right width as per USB spec, but these traces are short enough that it might not matter. You'd probably need to go four layer to actually meet spec while keeping trace widths reasonable.

Title. I assume C3R is newer and improved over the main branch, but I'm unsure if it's finished because it wasn't merged with the main branch. Thanks in advance.