Drawing high current without any application functionalities.

RE: Drawing high current without any application functionalities.

Elfving — Tue, 19 Apr 2022 06:43:49 GMT

No problem at all!

Regards,

Elfving

RE: Drawing high current without any application functionalities.

manjiw — Mon, 11 Apr 2022 03:13:07 GMT

Hey,

Thanks for your suggestions. As for now we've implemented a watchdog and improved our logging system.

We were not able to recreate the issue again, which tells me it is a very rare firmware lock-up. Softdevice and timers get disabled to carry out certain operations but they return to enabled states afterwards. Some form of lockup could occur in between these operations.

Regardless, we will keep monitoring this issue and see if the problem persists in the future.

Cheers for your help.

RE: Drawing high current without any application functionalities.

Elfving — Wed, 06 Apr 2022 09:17:27 GMT

Hello Manjitha,

In general, a watchdog sounds like a good idea.

Have you checked if this might be due to any assert? I.e., by making a led blink in the hard fault handler, or anything similar?

Is disabling Softdevice and timers any part of your application?

Have you tested if this is happening on a DK as well?

Regards,

Elfving

RE: Drawing high current without any application functionalities.

manjiw — Tue, 05 Apr 2022 00:26:19 GMT

A quick update from my end. This is so far the diagnosis and approach we're taking.

Observed symptoms of a ‘dead’ device:

No Bluetooth information being advertised
No application layer functionality
Current draw of 3-4mA
Voltage from battery dropping over time
1. Once disconnected from battery, the battery voltage will readjust to a ‘healthy’ potential

Potential reasons for observed symptoms:

Soft Device being disabled
Timers being disabled
& 4. If both the Soft Device and the Timers are disabled the firmware will enter a constant loop of nrf_pwr_mgmt where (as tested) approx. 4mA of current will be drawn and the voltage output from the battery will drop.

Potential solution to the issue:

Implementing a watch dog which will timeout if it is stuck in the nrf_pwr_mgmt loop.

Any other insights are welcome. Cheers.

RE: Drawing high current without any application functionalities.

Elfving — Fri, 01 Apr 2022 14:01:23 GMT

Hello,

I will have to get back to you on this next week.

Regards,

Elfving