Shows an example of how to sleep from LP3 (run mode) and wake-up
from both LP1 and LP0 by using the RTC compare wake-up triggers

    1. On power up, device is in LP3 (LED2 and LED3 on)
    2. Push SW2 push button and the device will go to LP1 sleep mode
       (only LED1 on)
    3. After 7 seconds the device will wake up (only LED2 on)
    4. Push SW3 push button and the device will go to LP1 sleep mode
       (only LED1 on)
    5. The device will wake up every second and toggle LED1 then go back to
       sleep
    6. After 7 seconds the device will stay awake (only LED2 on)
    4. Push SW1 push button and the device will go to LP0 sleep mode
       (only LED0 on)
    5. After 5 seconds the device will wake up and restarts (three blinks on
       LED3 then goes to step 1)