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Detecting Power Off

Posted: Tue Nov 11, 2014 1:47 am
by jkeogh
Hello,
I wish to detect (electrically) when a FitPC3 has completed it's power down sequence, that is (in Windows) when one selects "Shutdown".

As the USB power remains on I can't use this and I have tried using the Serial port e.g. RTS voltage, but it remain "Low" after shutdown from Windows.

Is there a test point somewhere on the one of the boards I can use?

If I could piggy-back off the front LED that would be good.

I will be using a photo MOS relay (SY4090) to do the detection.

Thank you,
John Keogh

Re: Detecting Power Off

Posted: Thu Dec 18, 2014 9:28 am
by mbirger
SLP_S3# is the signal indicating entering S3 (sleep) state in fit-PC3, where most of system functionality disabled.
It can be sampled on Extension connector P10 pin B43. See file attached.