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As I understand, like most Linux systems, it's not recommended to simply pull the power from Beaglebone. Instead we should shut it down, either by pressing the power button or running a Linux command. Next we need to wait for a bit before disconnecting the power, this gives it time to shut down cleanly, so preventing corruption of the filesystem.

My question is, how do we know when it has finished shutting down, so we know when it's safe to disconnect the power? I understand that the USR0 LED blinking indicates Linux kernel activity, when that stops blinking is it safe to pull the power?

Ideally I'd like to be able to determine that it's shut down by monitoring the state of a pin. Is there any pin on the Beaglebone that will go high or low when the system has completed shutdown? If not, is there configuration I could do to set a pin to behave like this.

I'm trying to create a circuit, external to the Beaglebone that can pull the BB's power pin low to initiate shutdown, then, once it detects that shutdown is complete, it will disconnect power to the Beaglebone.

I'm using a Pocket Beagle, but am interested in any insight on solving this for any member of the Beaglebone family, I can likely adapt a solution for the Pocket Beagle.

Thanks!

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  • \$\begingroup\$ You could measure the current, maybe? Won't be necessarily be zero since there are other things being powered but might be noticeably lower. Or use a timer if the shutdown is fairly predictable. \$\endgroup\$
    – DKNguyen
    Dec 20 '19 at 14:35
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    \$\begingroup\$ Add something to the kernel to set a particular output when shutdown is completed or at least advanced far enough. \$\endgroup\$ Dec 20 '19 at 16:27

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