|Note:||As soon as the sleep command is issued the unit will go to sleep. If the proper precautions are not taken, filesystem corruption can result as the sleep mode removes all power from the CPU and other peripherals on the SBC|
The addition of a microcontroller on board this SBC allows it to play a supervisory role over the CPU.
Low power sleep mode will remove power from all of the rails, turning off the CPU and every other peripheral save for the microcontroller. This mode offers extreme power savings, only requiring around 90 mW of power, with the ability to wake up after an arbitrary timeout (up to 1847297s, which is 21d 9h 8m 17s) with a 1s resolution. In order to enter this mode, issue the following command:
tsmicroctl --sleep --timewkup <time in seconds> --resetswitchwkup
Waking up from a sleep will take roughly 4-5s from when the timer expires or when the reset button is pressed. This is normal bootup time for the CPU.
Note that both --timewkup and --resetswitchwkup are optional arguments, you can pass none, one, or both. If no arguments are passed then the SBC will remain in sleep mode forever, until power is removed completely and re-applied. This can be useful instead of halting in linux as sleeping would consume far less power than simply halting the CPU. Be aware however, that if the Super Caps are installed they will keep power to the on-board microcontroller for a very long time. If the Super Caps are used than an external wakeup via timer or reset switch is highly recommended.