nRF5340 - JLink Error message

[Gabriele]

Hi guys,

I was working on my nRF5340 based custom board.
From a certain point on the nRF5340 stopped to accept any command from J-Link (SWD link).
For example, in response to a command like this

$ nrfjprog -f nrf53 --pinreset

an error message is printed out

"ERROR: JLinkARM DLL reported an error. Try again. If error condition persists, run the same command again with argument --log, contac Nordic Semiconductor and provide the generated log.log file to them."

You can find the log in the attached file.

Furthermore, lots of messages 
*** Booting Zephyr OS build v2.3.0-rc1-ncs1  ***<CR><LF>
*** Booting Zephyr OS build v2.3.0-rc1-ncs1  ***<CR><LF>
..
are popping out from UART

What happened ?

Thanks

[Vidar Berg]

Hello,

The log indicates that there's no communication between the target and the programmer. It's hard to say why it suddenly stopped working, but I would suggest starting by going over the connections. Are you using a standard programming cable or a custom one?

Best regards,

Vidar

[Gabriele]

Hi Vidar,
System was stucked in a auto-resetting cycle.
It was my fault. Early on after power-up, my test program pulled low a GPIO, which in turn triggered an external reset logic.

Thank you for feedback

Gabriele