2019-08-14 11:15 AM
2019-08-14 12:17 PM
Well, the STM32F042x4 / STM32F042x6 data sheet states "USB 2.0 full-speed interface, able to run from internal 48 MHz oscillator and with BCD and LPM support"
and it worked for me (on a prototype).
Frank
2019-08-14 04:20 PM
It's thanks to a so called Clock Recovery System, CRS, a module which fine tunes the internal RC oscillator to USB's SOF (or to an external pin).
AFAIK it's in L4 (but not in 'L476), 'L0, 'F0, 'H7; I don't know how's it with 'G4.
JW