@thebootloader Hi! I'm the author of Supriya, not Andrew Clarke, although he's a great guy and my most public power user. I've been writing the library basically solo since 2014.
@thebootloader just having a listen, there is a board package called STM32Duino for the Arduino ecosystemAlso, STM do have reference manuals for the HAL/LL APIs, I’ve downloaded them for several families, despite hating Cube with a passionI generally dump HAL in favour of LibOpenCM3, and have coded synth oscillators, envelopes, and SVGA monochrome that barely needs any CPU time using these API’s#STM32