Problems with PowerManagement_ForceSystemPowerDown (Powerdown sample)

[DanielHerreraC]

Hi everyone.

I have problems with the Azure Sphere Powerdown cycle; even using your sample code* : .. /Samples/Powerdown

I seems to does not matter the time that I passes as a parameter to the function

ForceSystemPowerDown(unsigned int maximum_residency_in_seconds);

on line static const unsigned int powerdownResidencyTime = 600;

The time durring which the app is in low voltage (Powerdown) is only 30 seconds. afther that the device reboot

I have tested it with 2 boards : the Seeed MT3620 Mini Dev Board and the QIIO q200.

Do you have any idea how to fix this bug?

Thank you very much, your help will be greatly appreciated.

Dan

*the only modification are those necessary for used with my developments boards like hardware définitions, etc.

[cawhitworth]

Hi; I'm unable to reproduce this on an RDB - powerdown works as expected, with the device remaining asleep for 10 minutes (after the modification to powerdownResidencyTime indicated).

This could be an issue with the wiring of the boards/modules being used here - using power management requires the PMU_EN pin to be tied to ground (which must be done manually on RDB revisions 1.0 through 1.4, but is pulled down by default on revision 1.6 and up). I don't believe this pin is brought out on the AI-Link module used by the Seeed mini dev board, so it would depend on how the module itself is configured; I'm not familiar with the Qiio part - you'd have to ask them for clarification.

You can check to see if this is the cause - with the dev board attached over USB, attach a serial console to the recovery UART (which should the highest-numbered UART on the FTDI interface) at 115200 8N1, and observe what happens when the device attempts to enter power-down. If there's a line which says [PLUTON] !! ERROR: ERROR: Clearing RTC PMU_EN register failed to power down device, it is likely this is the cause (i.e., PMU_EN is not pulled low).

There are further notes on power down mode and hardware considerations here: https://learn.microsoft.com/en-us/azure-sphere/hardware/mt3620-hardware-notes#power-down-considerations

Thanks;
Chris

[DanielHerreraC]

Hi

Thank you very much for your reply.

I'm going to investigate in the directions you point me to. If I find the answer, I will write it here.

Have good day

Dan

[DanielHerreraC]

Hello,

I add the information I got:

The QIIO team confirmed to me that they disabled the Powerdown because it caused problems with their board (installed images for proper functioning).

The Seeed team never responded to my emails.

Thanks @cawhitworth for your help!