> Próbowałeś wygenerować projekt przez STM32CubeMX?

Dzięki! Popróbuję. A tymczasem znalazłem możliwą przyczynę:
"The USB standard requires a 1.5 k? pullup resistor on D+, but this board is known to
have a wrong value (R10 on the board). It ships with either a 10 k? resistor or a 4.7
k? resistor, but it should be replaced with a 1.5 k? resistor, or put an appropriate
resistor value (e.g 1.8 k?) in between PA12 and 3.3V. It is also true that some PCs
are tolerant of incorrect value so, before you change the resistance, you can try if
it works in your case."