Wake from deep sleep works while debugging but not when running standalone

RE: Wake from deep sleep works while debugging but not when running standalone

Mark Q — Thu, 10 Mar 2022 18:35:14 GMT

Further clarification from Andrew:

If I place the bt_scan_stop() call after the printk() call, it doesn't work. So it seems that there needs to be a delay after calling bt_scan_stop() before going to sleep if you want to be able to wake up. That's a bit odd, but we can work around that.

RE: Wake from deep sleep works while debugging but not when running standalone

Einar Thorsrud — Thu, 10 Mar 2022 07:49:27 GMT

Ah, yes, sorry. There is a copy-paste error. It should have been:

It works for me if I take your example and call bt_scan_stop() on the on the first line in go_to_sleep() (so line 56 in main.c).

RE: Wake from deep sleep works while debugging but not when running standalone

andrew_alloy — Wed, 09 Mar 2022 22:24:12 GMT

Line 56 is inside go_to_sleep(). Calling it iteratively doesn't seem to make sense...I think you may have made a typo in your explanation?

RE: Wake from deep sleep works while debugging but not when running standalone

Einar Thorsrud — Wed, 09 Mar 2022 13:04:17 GMT

It works for me if I take your example and call go_to_sleep() on the on the first line in go_to_sleep() (so line 56 in main.c).

RE: Wake from deep sleep works while debugging but not when running standalone

andrew_alloy — Tue, 08 Mar 2022 20:48:35 GMT

Great. I had tried to do that unsuccessfully but I was guessing what I should do.

Would you be able to share the cleanup code that worked for you?

RE: Wake from deep sleep works while debugging but not when running standalone

Einar Thorsrud — Tue, 08 Mar 2022 20:34:35 GMT

Hi Andrew,

It seems wakeup from system off works properly after cleaning up properly before entering system off (stopping BLE activity etc.), and that is anyway a good idea. I am not able to explain why that is needed though, but I have unfortunately not been able to digg properly into this yet.

Einar

RE: Wake from deep sleep works while debugging but not when running standalone

andrew_alloy — Tue, 08 Mar 2022 02:01:09 GMT

Hi,

Do you have an update?

Andrew

RE: Wake from deep sleep works while debugging but not when running standalone

Einar Thorsrud — Fri, 04 Mar 2022 14:34:29 GMT

Hi,

Thanks for the sample. I see the same in my end. I will look more into it and get back to you.

RE: Wake from deep sleep works while debugging but not when running standalone

andrew_alloy — Thu, 03 Mar 2022 21:50:17 GMT

Hi,

I stripped down a version to post here.

Be sure to use SDK version 1.8.0. Open the project from the central folder.

Run it and wait for 5 seconds after you see the message "Scanning successfully started" on the UART console.

After 5 seconds you should see:

Scan timer expired

I: e: sleep_event Sleep Event

Going to system off...

That's when you need to connect P0.27 (top left on dev kit) to 3.3V to wake it up.

With the debugger connected you will see it boot up again. Without the debugger connected, you will not.

devzone.nordicsemi.com/.../4034.example.zip

RE: Wake from deep sleep works while debugging but not when running standalone

Einar Thorsrud — Thu, 03 Mar 2022 16:06:33 GMT

I see you are running this on a DK. Can you upload your (preferably minimal failing) project here along with instructions on how to run it to reproduce the issue?

RE: Wake from deep sleep works while debugging but not when running standalone

andrew_alloy — Thu, 03 Mar 2022 02:19:18 GMT

I've tried calling the same pin configuration functions right before the call to pm_power_state_force just to be absolutely sure but it still fails when the debugger is not attached.

I also tried having it sleep from the main loop rather than an event callback but that didn't work either.

I see that the code executed is:

NRF_STATIC_INLINE void nrf_power_system_off(NRF_POWER_Type * p_reg)
{
    p_reg->SYSTEMOFF = POWER_SYSTEMOFF_SYSTEMOFF_Enter;
    __DSB();

    /* Solution for simulated System OFF in debug mode */
    while (true)
    {
        __WFE();
    }
}

Call stack:

So in debug mode the SYSTEMOFF register being set to 1 doesn't do anything, and it executes __WFE() to simulate system off mode. I can recover from that with my wakeup pin. But in standalone operation it never comes back on. Something is fishy but I can't think what it could be.

I also tried changing it to active low instead of active high but that didn't make a difference.

RE: Wake from deep sleep works while debugging but not when running standalone

andrew_alloy — Wed, 02 Mar 2022 17:58:18 GMT

Thank you. That makes sense it can't really sleep while debugging. But it seems to do a good job of pretending, as it does reboot when I "wake" it. So I suppose it's going through the motions but not really shutting down the power, understandably.

The wakeup pin is only configured by those lines of code in one place at startup and never changed again.

I'm struggling to think what could be different when running "for real".

RE: Wake from deep sleep works while debugging but not when running standalone

Einar Thorsrud — Wed, 02 Mar 2022 13:38:31 GMT

Hi,

The nRF is not able to enter system OFF mode while debugging, so in that case it does not actually happen. But without a debugger this should work, as it looks like you have correctly configured the wakeup pin. Could it be that in Case 1 (the failing case), you reconfigure the wakeup pin or similar, so that it is no longer configured as sense? If that is not it, perhaps you can see if you can reproduce this with a minimal sample on a DK so that I can test on my end?