An example on how to setup the ZephyrOS Device tree overlay PWM on a bluepill board.
To build, first install Zephyr using a python virtual environment https://learn.adafruit.com/blinking-led-with-zephyr-rtos/installing-zephyr-linux
Then:
workon zephyenv
source ~/zephyrproject/zephyr/zephyr-env.sh
west build -p -b stm32_min_dev_blue
west flash