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my first post here. Thanks for having me. I've seen many posts discussing the use of GLOBAL_EN and GND for turning the Pi4 on. I'm interested in using this to turn the Pi4 OFF and leave it OFF long term when necessary. I'd like to use a SPST switch to turn off the Pi4 and would like to know if it will cause damage to leave it in this state long term. I have confirmed on my Pi4 that shorting these pins does remove power.

As I understand from this post that:

shorting GLOBAL_EN to GND will in fact boot the RPi 4 from halt, poweroff or 
shutdown when the EEPROM firmware is configured iaw the documentation.

Also from this post that:

GLOBAL_EN is connected to the PMIC. Connecting it to Gnd stops it working, so all power rails die.
Releasing it allows it to sequencially bring up the power rails, so allowing the SoC to start booting

My intention will be to use a wifi smart plug to power cut mains power from the Pi4 but in the case I forget that I shut it off with the SPST switch could that cause an issue? I'm assembling something similar to this Pi rack mount but they only provide details for the Pi3.

Thanks.

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You could use GLOBAL_EN and it is quite safe. You should ALWAYS shutdown BEFORE use.

It is not necessary on the Pi4, as it has on-board hardware to shutdown the PMIC, although this is disabled by default, but it is easily enabled. (I have not implemented this as I only shutdown when I want to remove power.)

All recent Pi models with PMIC can be put into a low power state.

The original Pi4 put the MxL7704 power management chip into a low power state when off - turning off the 3.3V supply and effectively totally shutting down the SoC.

See https://raspberrypi.stackexchange.com/a/114108/8697 and https://raspberrypi.stackexchange.com/a/100234/8697

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  • Thanks for the info. I connected the SPST switch between GLOBAL_EN and a ground pin and left it off overnight. I learned that this shuts down the 3.3V pins but leaves the 5V pins powered up.
    – mall_face
    Jan 26 at 21:55

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