Wanting an alternative to the Black Magic Probe, I took a look into DAPLink which is backed by Mbed. It uses CMSIS-DAP which is supported by OpenOCD which means it is supported by virtually every IDE and framework. As with the Black Magic Probe and many popular projects, the STM32F103 is supported. It took some time to parse through the code, documentation, and existing designs, but I got a schematic together.
I usually post images of my schematic and layout, but I’m making it a point to throw everything on Github so that everyone has full access to my designs. Check it out!
Assembly was straightforward as always. I didn’t have all the right components so I had to make do. The part that finally made DAPLink a viable option was the GCC support. It was in development while I did this project, but now appears to be mainlined. After compiling from main and uploading the bootloader and main program, everything worked! Here it is programming a little board I designed for UR@B training.