DIY STM32 Programmer (ST-Link/V2-1)
ST-Link devices are almost essential when developing software for the STM32 MCUs. They are relatively cheap and easily available.
They roughly fall into two different categories. ST themselves make a number of them and they all work quite well. There are also a lot of Chinese clones available and while they have some limitations they also work quite well.
Original ST-Link V2.1
The schematic of the original ST-Link is readily available
Schematics
Based on ST's original schematics, creating a version using only parts from JLCPCB's parts library was easy.
One thing I left out was the serial resistors of the programming header. This might very well come back and bite me in the ass but space is going to be at a premium.
PCB
The final rev. a layout looks like this:
The KiCAD 3D model:
