I just went to charge my kitchen scale and it wouldn’t work until I dug out a USB-A -> C cable and plugged it into my desktop…
It just reminded me of how many devices like that I have. This scale, my wife’s sound torc, some car jumperstarters, and I think a one or two more…
I assume it’s because they just slap a usbc port on a dumb 5v circuit that doesn’t have a power negotiation controller. So the cable and the charger cant figure out the power needs of the device are and just never send any.
I worked on an embedded product, on prototype there were pullup resistors on the RX/TX lines we used to plug a USB FTDI to do some debug. At manufacture they removed them, it created a floating RX that sometimes injected character that broke uboot…
I love stories from hardware / embedded design. Reminds me that black magic is real, and it’s a miracle any of this works.
What is completely incredible, is that there is some simple embedded devices, be it a thermostat, dishwasher, etc, that sold thousands/millions of units, and the firmware is done by one guy, a simple developer, and when it works, it is not touched again.