A-star 3.3V and sleep mode

short version: Does the ATMega32U4 3.3V regulator continue to supply voltage/current (at UCap) if the cpu enters any of the SLEEP instruction invoked modes ?

long version: What I can see in the ATMega32U4 documentation is that the 3.3V regulator primarily exists to power the on-chip USB pad. Certain USB interrupts appear to be available during all the SLEEP modes, unless UVREGE has explicitly disabled the USB pad regulator. Beyond that, I think that 3.3V will continue to be available, but I’m unsure that I might be missing something.


We think you are correct. The ATMega32U4 3.3V regulator is separately controlled by UVREGE and is not affected by any of the sleep modes.

- Amanda