25.6.7 Low-Power VREF in Active Mode

During active functional mode, the Brown-out Detector (BOD33) and the main voltage regulator (VREG) can reduce their power consumption by using a low-power voltage reference (ULPVREF).

The low-power voltage reference is started after power-up and is available when the ULPVREFRDY bit in the STATUS register is high. The ULPVREF Ready (ULPVREFRDY) interrupt can also be used to detect a zero-to-one transition of the STATUS.ULPVREFRDY bit.

Writing the VREF bit in the BOD33 register to '1' selects ULPVREF as voltage reference for the BOD33.

If the chip operated in PL0 ((PM->PLCFG.PLSEL=0) or Performance Level is disabled (PM->PLCFG.PLDIS=1), writing the VREFSEL bit in the VREG register to '1' selects ULPVREF as voltage reference for the main voltage regulator.

Note: The ULPVREF reference cannot be used in PL2 mode.