Le Potato, Sweet Potato, and La Frite feature many wakeup sources.
One of the sources is an always-on timer. You can set the timer to trigger an interrupt for a time in the future and then shutdown or suspend the system. Once the timer hits the target time, the board will wake up.
# wake up in 20 seconds
echo +60 | sudo tee /sys/class/rtc/rtc0/wakealarm
sudo systemctl suspend
# after 60 seconds, the system should wake up from suspend
# clear wake alarm so another one can be set again
echo 0 | sudo tee /sys/class/rtc/rtc0/wakealarm
This feature is useful for lowering power consumption until the device is needed again for processing.