This repository contains an USB-C-to-SPI-flash adapter that is compatible with stm32-vserprog and also has integrated level-shifters towards the SPI flash. This was created mainly to try out the JLCPCB assembly service and because there is no convenient way to program 1.8V flash chips with the "Bluepill + mess of wires" setup I was using before. The pinout is arranged such that it matches the common flash test clips.
Furthermore, there is a simple breakout board that flash chips can be directly soldered onto if space in the target device is too tight to use such a clip (this is mainly useful when reverse-engineering third-party hardware).
The respective fab directories contain fabrication data (and in the case of
the adapter, JLCPCB-style assembly data) for the boards. As JLCPCB cannot
populate connectors at this time, those had to be assembled manually:
- The dual-row 100mil connector is either a plain dual-row header or a shrouded/keyed one.
- The USB-C connector is a particular family that I sourced from AliExpress. There doesn't seem to be alternative from western distributors that's similarly convenient to solder.
The way the target is powered can be selected through the pin header above the USB port: The target can be self-powered (no jumper), powered from the internal 3.3V rail (jumper between 3.3 and Vt) or powered externally (supply power between G and Vt).
The TRST/GND connector was meant as an extension that could be used (given a
modified version of stm32-vserprog) to keep a target device in reset while
accessing the flash to prevent interference. However, this does not really work
out mechanically, so it was never used.
Build stm32-vserprog using BOARD=stm32-jz01v20 and flash the firmware via
the TagConnect connector.