nRF52840-DK debugging ending in app_error_fault_handler

[Hugo Habicht]

Hi All,

we are seeing a problem when stopping for debugging that we end up in an end stop called "app_error_fault_handler" after a few single steps.

This thread sheds light onto what is happening:

https://devzone.nordicsemi.com/f/nordic-q-a/37024/nrf52840-example-application-runs-into-app_error_fault_handler

So it seems as soon as the "softdevice" is running the debugger stops working. The solution seems to be this segger "monitor mode" debugging:

www.segger.com/.../monitor-mode-debugging

But this requires some extra software and extra hardware because the on board jlink is not working with the only difference (I think) being one bit different written into the processor when stopping to keep interrupts running.

So can somebody confirm / deny if this "monitor mode" is really not working on the Nordic DK boards? Also can somebody confirm / deny if this "monitor mode" is really working to use a debugger in single step mode with the Nordic "softdevice" running? We ran into so many problems with this segger stuff that we are considering to pull the plug and look elsewhere for bluetooth ics. Also I do not think those segger type of business models should be supported.

Kind Regards,

[haakonsh]

You can try the https://github.com/NordicPlayground/j-link-monitoring-mode-debugging tutorial. 

[Hugo Habicht]

Yes, I had seen that.

But does it work with the jlink integrated on the nordic DK board though?

And to be honest: Nordic "Playground" does not really suggest software for professional use to me.

[haakonsh]

Only for 'evaluation' purposes. You need a JLink Plus/Ultra/Pro for commercial use. 
You might be able to buy a license for Monitor Mode Debugging with your OB JLink though.