Debugging a Nordic MCU (feather NRF52) using Segger J-Link I have an Afafruit NRF52 board with SD 132 and 5.1 dual fw bootloader.
I implemented RTT logging and controlling (input) and the code is compiled using arduinoBuilder with RTT and debug level 3.
The device uses to control DALI lights but sometimes it hangs, I can see that it does not responses to input and light level never changes.

I want to debug it, maybe getting a stacktrace to see where it hangs, hoping it's a software issue.

Any leads on how to do that ? 
Tutorial maybe ?
I haven't tried this, but OpenOCD supports both the nRF52 and the JLink.  Something like (on Linux):

openocd -f /usr/share/openocd/scripts/interface/jlink.cfg -f /usr/share/openocd/scripts/target/nrf52.cfg


might start OpenOCD.

You can then connect with (nRF52 flavour of) gdb (arm-none-eabi-gdb). 

You can find information about using gdb with OpenOCD here and here.