-102 error when flashing nRF52840 Dev Kit via J-Link Plus

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

TUlric — Fri, 25 Apr 2025 21:34:26 GMT

Kenneth, thanks for all your suggestions. I did end up ordering another nRF52840DK board (which I needed for other reasons) and found it also failed. So, that led me down the path of re-examining all of my settings. Fortunately, that exposed the issue. It is not likely that others will run into this issue, but I thought I'd explain anyway to provide closure and give you another thing to suggest if you see other strange issues like this. The problem was that I'd previously set the J-Link VTref to a fixed value to work with another board that I was using. It still worked with that board, but not on the nRF52840DK, until I removed that override. In this case the override was visible by using the ShowHWStatus command in J-Link Commander and was removed by sending "VTREF 0".

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

Kenneth — Tue, 18 Mar 2025 14:24:42 GMT

I unfortunately don't have any other good suggestion here, possible try on a different DK if you have or other hardware for that matter. Possible connect a logic analyzer to the SWD pins to check if the pins are driven high/low as expected.

Kenneth

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

TUlric — Mon, 17 Mar 2025 14:23:51 GMT

Also, in case it is a clue... I can see, when I have the UART connected, that the SEGGER is able to do the reset, just not the programming.

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

TUlric — Mon, 17 Mar 2025 14:13:32 GMT

OK, I tried disconnecting the UART and powering the DK via P21. Still the same error.

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

Kenneth — Mon, 17 Mar 2025 10:01:16 GMT

Try to disconnect the UART for now, only connect the SEGGER. In addition power the DK through P21 (external supply) header.

Kenneth

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

TUlric — Sun, 16 Mar 2025 21:28:17 GMT

I had tried supplying power from USB connector J2 (the interface MCU, but only power, not digital) and from USB connector J3 (for the nRF52840 SoC) with the same results. Per your suggestion I tried using VIN on P21 (at 4.8V) and I got the same -102 error. Here are a couple of pictures of my setup.

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

Kenneth — Sun, 16 Mar 2025 10:53:49 GMT

The alternative I can see is to power the DK from the external supply (not using the USB), did you try that also? If that doesn't work, then it must be something fundamentally different. Maybe take a picture of your setup so I can check.

Kenneth

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

TUlric — Thu, 13 Mar 2025 19:17:53 GMT

Thanks for pointing that out. I am connecting the debugger to P18 as described in that reference and I have also probed the pin to ensure that the signals appear to be correct. I am using a "Segger J-Link Adaptor CortexM" which flips the pins to match the CortexM expectations. I had not tried switching SW7 since I thought that was for trace and not just external debugging. But, I did try switching it after your suggestion and it did not affect the result. I.e. I am still getting the -102 error when I attempt to flash. Were there any clues in the log.log as to what was going wrong?

RE: -102 error when flashing nRF52840 Dev Kit via J-Link Plus

Kenneth — Mon, 10 Mar 2025 11:47:01 GMT

[quote user=""]I get an error and the flashing fails when I attempt to flash the nRF52840 DK via an external J-Link Plus connected to the Debug In connector (P18).[/quote]

Have you followed:
"The Debug in connector (P18) makes it possible to connect external debuggers when the interface MCU USB cable is not connected, or the Development Kit (DK) is in nRF only mode."
https://docs.nordicsemi.com/bundle/ug_nrf52840_dk/page/UG/dk/hw_debug_in_trace.html

Kenneth