System_off Sample project not completely working with bl653

[jspiller]

Hello,

I am trying to run the system_off sample project to measure some low power currents. The sleep works as expected but once it reaches:

	pm_power_state_force(0u, (struct pm_state_info){PM_STATE_SOFT_OFF, 0, 0});

It does not go into deep sleep and gets stuck in the while loop afterwards. Any idea why this is happening? pm_power_state_force() returns True.

Thanks, 

Jacob

[Jared]

Hi,

Which example, this?  

It does not go into deep sleep and gets stuck in the while loop afterwards.

Is the example unmodified? How do you verify that it doesn't go to sleep, by measuring the current? If so, what current do you measure?

regards

Jared 

[jspiller]

Hi Jared,

Yes it is that sample project and yes unmodified. So when it goes to sleep it measures ~0.5mA with the debugger disconnected which seems normal and then when it should go into deep sleep it measures 3mA. I am measuring through jumper J7 with SB1 cut. It also spits "ERROR: System off failed" on the UART and enters the while loop. I have tried it on a nRF52840dk as well with the same error.

[Jared]

Hi,

I was able to reproduce this on my end. It seems that the application asserts and never goes to sleep. I tried writing to the SYSTEM OFF register directly instead of calling pm_power_state_force() which worked:

You can use that as a temporary fix. I'll report this internally and will be back with more.

regards

Jared 

[jspiller]

Hi,

Glad to know it wasn't just on my end. Is that workaround functional on a nRF52833 based board however, I was only able to find that register on the nRF5340 and nRF9160.

[Jared]

Hi,

For the nRF52 series you would have to write:

     NRF_POWER->SYSTEMOFF = 1;

regards

Jared

[Jared]

Also, seems like this has already been reported. See this thread for suggested solution.