Took me 3 days of soldering, but it works!
I can connect it to a Librem 5 and it automatically does all the needed PD stuff to expose its UART over USB-C 😁 It's also capable of a lot of other PD magic as a USB PD analyzer / injector / filter.
However, while these solder joints made a good job lasting till I got the firmware PoC working, it doesn't seem like they're going to last much longer... More soldering ahead 😫
#debubo #kicad #stm32 #usbpd #librem5 #shotonlibrem5 #diy #electronics #oshw
@dos why the STM32 and the CH342K instead of putting a single MCU on there with USB support?
@martijnbraam I considered that, but eventually decided against:
a) CH342 has an integrated LDO; BOM wouldn't get shorter by getting rid of it
b) this way UART channel works regardless of what you're doing in firmware; one less thing to care about
c) there are free samples available for STM32G071CBT6; no samples for USB-equipped G0B1/G0C1 😄
