Detecting Loss of Power

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3F800000
Posts: 12
Joined: Wed Apr 25, 2018 6:36 pm

Detecting Loss of Power

Thu Jan 10, 2019 10:26 pm

Working with ATSAMA5D27.

Is it possible to detect of loss of primary power so that under VDDBU power I can do shutdown tasks, and enter backup mode.

Perhaps an interrupt could be generated when WKUP transitions low? I've looked extensively at the examples of software commanding the part into various backup modes, but it is not clear how to trigger this at the point that backup power is being utilized.

Thanks
blue_z
Location: USA
Posts: 1906
Joined: Thu Apr 19, 2007 10:15 pm

Re: Detecting Loss of Power

Fri Jan 11, 2019 11:11 pm

3F800000 wrote: Is it possible to detect of loss of primary power so that under VDDBU power I can do shutdown tasks, and enter backup mode.
Only with external circuitry.
You may be confusing AC line monitoring with detection of power failure.
A power supply may have the capacity to maintain power to the system for tens of milliseconds, so monitoring the AC line is preferred.

The ARM processor of the SoC is powered by VDDCORE, so VDDBU power is not sufficient to perform any "shutdown tasks".

Regards
3F800000
Posts: 12
Joined: Wed Apr 25, 2018 6:36 pm

Re: Detecting Loss of Power

Sun Jan 13, 2019 9:56 pm

Thank you.

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