USB with libopenCM3 on the STM32F070F6
This specific part doesn't work out of the box with the OpenCM3 STM32 F0 USB example/testcase for two reasons:
- The USB pins (PA11/PA12) are hidden behind a mux on pins PA9/PA10 and need to be switched in. This physically connects the USB peripheral to the pins.
- The STM32F070 must use an external oscillator to drive the 48MHz USB clock. My design used a 12MHz HSE, which libopencm3 didn't have a built-in clock configuration function for.