Priming the System

Priming, or arming the ATTiny Daemon, is very simple and done by setting the option primed in the configuration file to the value true. As soon as you restart the daemon (sudo systemctl restart attiny_daemon) or reboot the system the value is written to the ATTiny Daemon and the watchdog functionality (resetting the RPi if it isn‘t accessing the I2C bus regularly) is enabled. Depending on the option force shutdown the ATTiny will also turn off the Geekworm UPS if the voltage sinks below the value stored in the option shutdown voltage.

But even without priming you get access to the measured voltages and the button functionality is available as well.

Important Caveat

Before actually priming the system the battery should be charged well above the warn voltage (around 0.2V higher should be safe). This ensures that the internal state machine is perfectly adjusted to the real situation. Furthermore, if you use the configuration options that rely on measuring the external voltage ensure that the voltage is more or less correct (using the respective configuration options). The voltage that is used to decide whether an external voltage is available is 4.75V (below that the voltage is no longer in the allowed range for USB voltages).