SED rebooting when detached from open thread network

[ShubhanshuG]

Hello everyone,

I am using open thread based mesh network on NRF52840.

The SED's gets rebooted when the devices are not connected to any parent. So, if my devices are in detached state, they start buffering the data untill they get back in the network.

I have been testing them and came to know if border router and ftd's are off, there is no parent connected to SED's then they get rebooted  after an uncertain period of time, I have check that if any FTD is left on, SED's have a parent but since border router is off they start to buffer data and keep buffering even if border router is off for 3 days.

But in case of detached mode, they can get rebooted in 15 min or may be in a day, that is totally random time, if the SED is getting rebooted I am loosing my buffered data. 

I figured out in my research that this is a known issue in nrf5 sdk for thread and zigbee 4.1.0 , but it got fixed in nrf5 sdk for thread and zigbee 4.2.0 . I have migrated to sdk 4.2.0 but I am still facing the same issue. 

Can someone please help me with the same, I will be extremely grateful.

[Jørgen Holmefjord]

Hi,

Hard to say what is causing the reset in your application. The default behavior when a function reports an error, or a HardFault is generated, it to reset the chip. 

If you enable NRF_LOG module in your application on the device, it should report a Fatal error if an error occurs. If you build the application in "Debug" configuration, the logger should also inform you about the exact error code, file name and line number where the error was reported. To debug a HardFault, you can also include the HardFault handling library in your application. 

Once you know where the error occurs, we can help you find a solution.

Can you post a link to this know issue that you found during your research? As far as I know, the Thread libraries are identical and untouched between nRF5 SDK for Thread and Zigbee v4.1.0 and v4.2.0, the latter release only made changes to Zigbee part of the SDK, see the release notes.

Best regards,
Jørgen

[ShubhanshuG]

Hi,

Thanks for a prompt response.

We are working with openthread mesh.

We did a trial where border router was off and 7 SEDs were connected to a parent(FTD in this case). we took the logs for more than 72hrs and none of them rebooted.

Then we took 7 SEDs and after they were commissioned, we switched off all the routers and hence they were not having any parent, all the SEDs got rebooted in this case in less than 24hrs. 

This test was conducted after we saw that SEDs were rebooting on site and we were not able to figure out issues.

In NRF5 SDK 4.1.0 there was an issue KRKNWK-4666 which says that SEDs were rebooting if not connected to a parent. 

So I assumed that this might be an issue with thread devices as well, as I was not aware that the issue was only addressed to zigbee network.

I will take logs for the entire time until SED reboots to get the fatal error. and then try to do hard fault handling as well. Do NRF devices have core dump so that we can have dump to check whats wrong with the devices. 

If you find something like this happening somewhere else also, or you get to know what might be causing this, please help.

Regards,

Shubhanshu