ST-LINK SWIM interface

• a basic implementation of the STM8 SWIM protocol running on STM32 (Bluepill or other)
• On the USB side the code behaves like a ST-LINK v2
• It is also pin compatible with ST-LINK v2 and the chinese clones
• With this code you can turn a Bluepill into a SWIM probe for flashing & debugging a STM8.
• Or you could flash it into a ST-LINK directly, and enjoy the fact that it now runs on open source firmware.
• The setup has been tested with stm8flash & openocd

Connections

• RST : PB6
• SWIM_IN : PB7
• SWIM_OUT : PB11
• add resistors as in schematic below (similar to STLINK)

Build

use platformio for building & flashing to a STM32 target.

Note

• the SWIM signal generation is based on code from the impressive but unfortunately defunct versaloon project.
• I don't have the ST-LINK USB protocol specification, so I guessed here and there, based on other code bases (stm8flash, openocd, versaloon).

TODO

• add target voltage sense
• USB DFU version compatible with STLINK bootloader
• vague plans to integrate STM8 with black magic probe, if I find the time ..