Detecting Power Off

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Joined: Tue Nov 11, 2014 1:32 am

Detecting Power Off

Post by jkeogh »

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

Post 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.
fit-PC3_P10.B43_SLP_S3n.PNG (31.1 KiB) Viewed 4490 times

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