How is the M5StickC Plus 2 turned off in the User Demo?

[foudrou]

Hello everyone,

I am enjoying using my M5StickC Plus 2 since I found the User Demo (https://github.com/m5stack/M5StickCPlus2-UserDemo) and started modifying it for my needs.

Everything works flawlessly but I don't understand how the device is turned off.

I think the function

void TEST::power_off()

in test.cpp does the magic (it no longer works when I comment it out along with its declaration in test.h) but I don't see it being called.

Sorry for the rookie question. I tried searching and was unable to find anything useful so far.

Thanks a lot,

Ben

[felmue]

Hello @foudrou

there is an alternate way which can turn off the device: if is_test_mode is true then at the end of test_loop() rtc_wakeup_test() is called which at the end sets POWER_HOLD_PIN to LOW turning off the device.

Note: not sure why it doesn't work when you comment out power_off() function as I also don't see it being called anywhere either.

Thanks
Felix

[foudrou]

Thanks @felmue,

I'll continue to play around with the demo to get a better grasp of it.

If anyone has another (ideally PlatformIO-based) demo to propose I will have a look at it.

Thanks again,

Ben

[felmue]

Hello @foudrou

M5StickCPlus2 has dedicated hardware (U8 etc.) to power off when the power button is pressed and hold. See schematic here.

Instead of setting POWER_HOLD_PIN low, the power off hardware pulls 3V3EN low which disables the 3.3 V DC/DC converter and thus killing the power to the ESP32.

Note: when the power button is hold long enough you'll see the green LED being turned on, indicating that 3V3EN is low.

Note: power off only works when run from battery.

Thanks
Felix