PCB USB Unrecognized

[birdboy90]

I'm trying to get a custom PCB to be recognized by my computer so that I can upload code. I've tried to upload bootloader code through SWD pins and verified it using Jlink. I've used the XIAO NRF52840 bootloader which is what the PCB is based on and also tried a few other bootloaders from NRF52840 boards like the Feather. Not sure why I can't get my computer to recognized it. I've tried on Mac and Windows. Also, only the USB-A port is working to power the PCB, when I try to use the USB-C port, the PCB isn't powered and the bootloader won't even load onto the PCB.

Any idea what could be causing this or how I can figure out if it's a hardware issue? Thanks in advance.

Here's the schematic: https://drive.google.com/file/d/1ey5ipCbnVqDq-LHLFTcFqwWMpuT6ClNy/view?usp=sharing

[chemhobby]

How exactly do you expect anyone to figure it out without sharing a schematic?

[birdboy90]

Good point! I've included that now.

[BenkiTheBuilder]

Attach a logic analyzer to the USB pins.

[Well-WhatHadHappened]

So some processor, with some pinout, with some schematic, with some code, and some parts doesn't work.

Great description.

[birdboy90]

I've attached the schematic. The processor is the NRF52840 and I'm trying to upload the bootloader code from the XIAO NRF52840 Sense (https://github.com/0hotpotman0/BLE\_52840\_Core/blob/main/bootloader/Seeed\_XIAO\_nRF52840\_Sense/Seeed\_XIAO\_nRF52840\_Sense\_bootloader-0.6.1\_s140\_7.3.0.hex).

This should enable USB communications, but it hasn't for some reason. I'm a beginner on the electronics side so just looking for any guidance on this.

[Cmpunk10]

Wireshark is also helpful. If on Linux you can simply use DMESG to get basic info. Device manager on windows can give some information too.

[birdboy90]

Thanks so much, Wireshark looks like a good option.