The NVMCTRL will continue to operate in any sleep mode where the selected source clock is running. The NVMCTRL interrupts can be used to wake up the device from sleep modes.
The Power Manager will automatically put the NVM block into a low-power state when entering sleep mode. This is based on the Control B register (CTRLB) SLEEPPRM bit setting. Refer to the CTRLB.SLEEPPRM register description for more details. The NVM block goes into low-power mode automatically when the device enters STANDBY mode regardless of SLEEPPRM. The NVM Page Buffer is lost when the NVM goes into low power mode therefore a write command must be issued prior entering the NVM low power mode. NVMCTRL SLEEPPRM can be disabled to avoid such loss when the CPU goes into sleep except if the device goes into STANDBY mode for which there is no way to retain the Page Buffer.