Wakeup on charge should depend on ext. Power

[phaupt]

Hello! In my scenario I want to use the system task as follows:

• "Min charge" threshold at 60%. If I remove external Power to the Pi, the PI should keep running until PiJuice battery is below 60%.
• Wakeup on charge at 0%. If external Power to the Pi is present, the Pi should be up and running.

The System events:

• "Low charge" = SYS_FUNC_HALT_POW_OFF

If PiJuice battery is 100% and then I remove the external Power to the Pi, PiJuice keeps the Pi running until it drops below 60%. This works as expected.

However, if external Power to the Pi is present AND the PiJuice battery below 60%, then it does not properly work. It wakes up the Pi and immediatly shutdown again. It runs in a boot/shutdown loop until the battery is charged above 60%.

Is it possible to use the "Min charge"/"Low charge" in a way that it also considers the presence of the external power? The PiJuice should only shutdown the Pi if battery is below 60% AND no external power is present (=not charging). Whenever it is charging, the Pi should be running. How can this be configured?

[tvoverbeek]

Connect a user function to the "No Power" event. This user function should enable the "Low Charge" event. At boot/wakeup disable the "Low Charge" event when external power is present.

[phaupt]

Thanks! Will give it a try.

Is the enabling/disabling of the "Low Charge" event a supported feature of the I2C Command API, I couldn't find it on the API documentation at https://github.com/PiSupply/PiJuice/tree/master/Software ?

[tvoverbeek]

OK. What I wrote before is not correct. The low charge event only occurs in the pijuice service. In its polling loop it checks the charge level and only triggers the action when no external power is present. Can you please explain how got in this boot/shutdown loop when the battery is below 60%?

[phaupt]

Raspberry Pi 4 with teslausb image

Firmware 1.6 (up to date) Reset all settings to factory default, then I've changed only these settings, using PiJuice CLI:

• Battery Profile BP7X_1820
• Charging enabled
• No buttery turn on

System Task: [X] System task enabled [X] Wakep on charge: Trigger level 1% [X] Restore [X] Min charge: Threshold 60% [X] Software Halt Power Delay period: 30

System Events: [X] Low charge: SYS_FUNC_HALT_POW_OFF

pijuice.service is enabled, active and running.

If the battery is fully charged, it keeps the Pi running even if I remove USB-C/Power until it drops below 60%. If I reconnect the USB-C/Power while the battery is still below 60%, it will do the boot/shutdown cycle.

[tvoverbeek]

Just ran a test on my Pi4/PiJuice with your settings and I do not get a boot loop when I apply external power with the charge level below the threshold. How do you power the Pi4/Pijuice combination? Via the PiJuice microUSB or via the Pi4 USB-C? I suspect some interaction with your teslausb version. It seems a heavily modified version from standard Raspberry Pi OS.