HSE oscillator when using USB

[David Ashman]

The STM32F303xB datasheet states that HSE oscillator should be used when using USB. I suspect it is because of the degraded accuracy of the HSI oscillator at temperature. I've had issues with CAN not working well with HSI at elevated temperature. Does anyone have experience using HSI vs. HSE for USB-CDC class virtual COM port? Thanks!

[waclawek.jan]

I don't think there is much experience out there. Why would anybody want to have an unreliable element in an already wacky interface, which has the potential to bite you in the least convenient moment?

Try to have a look at the HSI using oscilloscope.

Some STM32 out there can condition an internal RC oscillator based on USB SOF, but not the 'F3.

JW