In summary, using the new Deep Sleep mode allows applications that are inactive for long periods of time to dramatically lower average power consumption, and eliminates the need for an external switch to cut microcontroller power. Deep Sleep turns off the processor core, most peripherals, and SRAM to reduce power consumption to virtually zero. However, some features can be configured to remain powered, such as the RTCC to allow for timekeeping. Deep Sleep has several wake-up sources available, including INT0, the DSWDT, an RTCC alarm, and the ULPWU. While SRAM is powered-down, a few special Deep Sleep registers remain available for saving context information through Deep Sleep.