The Living PCB Design Thread

[Thomas73951]

Try "Subtract soldermask from silkscreen" option to plot gerber file. Then check the resulting gerber file with its viewer.

Awesome, that worked. Thank you

[Solastice]

Hi! This is my first time making a pcb and first time posting on this thread. I need some advice on a few things.

I'm working on making a replacement PCB for my AEK II with an STM32 F3 MCU. The STM32F302ZDT6 to be precise, since it has enough I/O pins for 105 switches and USB. It should be compatible with QMK? The QMK Doc just says any STM32 MCU so I figure it should be.

I have all the basic power circuitry done. I have a reset button and switch for the MCU. The plan is to have the USB_C Ports on dummy boards that just pass through the signal to the main board. I have one port wired already.

 I just need advice on a few things, in order of priority:
1) How to implement ESD Protection

2) USB Pass through - the AEK has two ports and I want to keep the functionality of the second if I can. Is it enough to just hook up the second port to the same Data lines the other port uses? And what about the CC pins on the second, do I pull them down or not?

any advice is appreciated

[Applet]

Is there a reason for doing it without a matrix? (just for fun is a good enough reason ). It'll be more painful to route for no particular gain. You could then use a smaller MCU.

1: I'd recommend to check the datasheet for the ESD protection-chip you plan to use, implementation can vary slightly. Most often, you just connect the D+ and D-, VCC and GND to the ESD IC that sits in parallel, but some sit in series, so make sure to read the DS. Placement should be close to the connector and protect the traces between connector and MCU.

2: USB is not a bus, so you can't connect a second device to the same data-lines, you'll need a internal USB-hub or multiple data-lines (like multiple cables) to get pass-trough. Since you are using a USB connector and not a dedicated cable (that could split into two at the PC side), I'd go with a internal hub.

I'd also recommend to change voltage regulator to a more modern one and reduce the capacitance of it's decoupling caps. Ideally, you want to keep your total capacitance for a downstream usb-device to below 10uF.

[Applet]

double post

[xBqcon]

So I'm using ai03's guide and noticed there's a problem with the USB. I get the message "Processing courtyard of “random-keyboard-parts:Molex-0548190589”: Unable to find segment with an endpoint of (162,58 mm, 18,998 mm)" . I found one post saying to switch out the USB footprint. Does anyone know of any USB footprints to use? I also looked into a usb type C HRO TYPE-C-31-M-12 but not sure what the rest of the pins do besides the ground, power, D-, D+. I'm a noob if it isn't already clear so any help is appreciated. Thanks in advance!

[Applet]

So I'm using ai03's guide and noticed there's a problem with the USB. I get the message "Processing courtyard of “random-keyboard-parts:Molex-0548190589”: Unable to find segment with an endpoint of (162,58 mm, 18,998 mm)" . I found one post saying to switch out the USB footprint. Does anyone know of any USB footprints to use? I also looked into a usb type C HRO TYPE-C-31-M-12 but not sure what the rest of the pins do besides the ground, power, D-, D+. I'm a noob if it isn't already clear so any help is appreciated. Thanks in advance!

The ai03 guide have a section that deals with how to implement USB-C: https://wiki.ai03.com/books/pcb-design/page/usb-type-c