nRF53 Device is Protected after programming and I cannot debug

[nsga333]

When i program our new nRF5340 based radio boards the program returns Device Protected for both cores on completion. It is also impossible to debug the board as my segger refuses to connect.

I found a case with a similar issue:

https://devzone.nordicsemi.com/f/nordic-q-a/75406/problem-to-debug-net-cpu-after-segger-update-and-new-nrf5340-chip?ReplySortBy=CreatedDate&ReplySortOrder=Descending

and have tried the suggested solution of:

put the following in the NET Code at the start of main:

NRF_UICR_NS->APPROTECT=0x50fa50fa;
NRF_CTRLAP_NS->APPROTECT.DISABLE=0x50fa50fa;

put the following in the  APP Code the start of main:

NRF_UICR_S->APPROTECT=0x50fa50fa;
NRF_CTRLAP_S->APPROTECT.DISABLE=0x50fa50fa;

This does seem to allow the debugger to connect, However i get a hard fault from the command.

Is there a suggested way around this issue?

[Sigurd]

Hi,

How are you flashing the device? With nrfjprog or west?

Take a look at the commands on this page on how to flash the image:

http://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.0/nrf/ug_nrf5340.html#programming-from-the-command-line

[nsga333]

I am using nRFProg to write the image through a Segger j-link ( I have upgraded to the latest Segger as well). This works fine with the older nRF52 boards. and also when i program a PDK. But as soon as I program our target the nRFProg reports that the device is locked.

Next time i wish to program the device i have to do an erase all to unlock it. I have seen it work for an hour or a few hours such that i can program it and it comes back unlocked so that i am able to debug it but after a period, maybe the next day it wil revert to programming as locked

[emag nioj]

every time there is a reset the protection goes on erasing all automatically.

It's a lot disturbing, now i need to update the NET core but i m not able to debug.

I enable FLASH ERASE then writing 0xFFFFFFFF on 0xFFFFF000 boundaries then the page is erased ready to write the code. In APP it's ok in NET no but how to debug????