How to use USB in an ISR (solved)

I have searched high and low in my quest for finding an ISR to process, 9600 Baud or in this range, USB data but in vain. Am I missing something?

I can see there are SERCOM handlers and I have an ISR running for a plain UART. But how about the USB?

Does anyone have a working example or can guide me where to look.


You realize that USB code is MUCH more complicated than UART.
The Zero code is in

Hello westfw

Thanks for the post. While not directly solving my problem it did made me search in a different way. While doing so I came across an, to me, unknown Arduino function: yield(); It solved my problem by scanning the SerialUSB inside my own version of yield(); even if this is not an ISR.