nRF52833 Can't connect after erase all

[Timor]

Hi,

I am unable to connect and program a custom board with nRF52833 after performing 'Erase All' using Segger IDE (V5.66).

Those boards were programmed a few months ago using nRF52840 EVB (version 2.0.2) and have been working fine. Now i had to update firmware, I executed 'erase all' and since then I can't connect and program the boards ('No idcode detected' error). Same problem repeated on 3 different boards (i didn't try more so that i won't lose all my boards). I tried to 'erase all' the nRF52833 EVB (by Fanstel) and no problem there. I was able to connect again and program. I tried using J-Link and through nRF52840 EVB (version 3.0.0), no success. I tried to recover the board through nRF studio but got an error (recover failed. unknown error). I tried "nrfjprog --recover" but that also fails (unable to connect, JLinkARM DLL reported error, log is showing unknown errors "-1"). J-link is updated to last version. The j-link connection to the custom board seems ok because i can connect to other boards.

Any ideas?

[Timor]

Update:

I figured out that debug out connector P19 on the new PCA10056 (V3.0.0) was changed so that PIN3 is now the interface select pin and PIN5 is GND. I revised my cable and got some improvement. One board i was able connect and program. Two other boards are still not working.

Using "nrfjprog --recover" i get an error saying nrfjprog could not identify the target device. if I use --log I get: "[  nRFXX] - Device does not have an ARM debug port".

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Update of update:

Using a lower debugger clock (125KHz) I succeeded programing another board. So it appears to be a hardware problem on my boards after all.