Hi All, 

I have got a fairly custom setup - whereby the APU2 board is powered by an ATX PSU, that also supplies power to 4 SATA drives with some custom circuitry to poweron the ATX PSU.

 

Question is - to shutoff the ATX PSU sensibly I need a pin somewhere from the APU2 board that goes to 0V when the system does a sane shutdown (i.e. OS shutdown and power off, and the power LED goes off) - but there is still 12V Supplied to the board with J18.

This "pin" - or output will be used by me in my custom circuitry to control the ATX PSU shutdown which will remove the 12V from J18 (and the 4 disks)

Ideally this would be something like a 5V whilst powered on and 0V when powered off ( with 12V still supplied to board ) - I *MIGHT* be able to make 3.3v work, but definitely not ideal.

Cheers

 

K

I guess you wanna detect when the OS has properly shut down before actually cutting power ?

You could use the extra gpio's on the nct5104d or (if you wanne do some soldering) one of the LEDs.
And then patch up the init system or kernel shutdown code to raise a signal there.

Doing it in the the final shutdown script - after filesystems have been unmounted / remounted ro, should be sufficient.
The major point of proper shutdown is having all pending buffers written out consistently and filesystems in a clean state.

--mtx