Note: Most "generic" STM32F103 boards only have a reset button, and not a user / test button. So the bootloader code always configures the Button input pin as PullDown. Hence, if a button is not ...

I developed a version where the TTL logic was replaced by a CPLD. This made the circuit much smaller. Instead of the Arduino Nano I directly integrated an ATMega32u4. This is flashed with the ...