RE: Debugging nRF52840 Dongle via J-Link to DK and Segger Embedded Studio

AnonEMoose — Fri, 28 Sep 2018 19:28:02 GMT

OK... I think I solved the problem, but I am not entirely sure how. Originally I used J1 pads on the dongle with a TC2050 pogo-pin connector. Reset does not exist on those pads (I now assume these pads are for programming only... no debug), so I had to tack a jumper from DK board, port P20 Reset pin to dongle, port P1, pad 10. I forgot to change this on my pinout list above.

I then decided to instead solder on a 2x5 pin header onto P1 and use a straight 10-wire ribbon cable to connect DK to the dongle. I still needed a jumper from Vdd on the DK to the VddOut pad on the dongle (one of the notched pads on the edge). HOWEVER, I made this change to a second dongle (i.e. not the same one I had issues with).

Viola, the Segger downloaded the example server program and immediately went into single step debug mode. So, I have no idea if my 1st attempt was a bad solder job or simply an issue with the 1st dongle... but I am back in business and debugging like a frog in fly season.

For those of you following along... don't waste time trying to debug with TC2050 pogo-pin cable (which are pretty awesome, I must say). Instead, solder 2x5, 0.05" (1.277mm) pitch, male pin header directly to the dongle's P1 pads; add another jumper from DK for the dongle's Vdd and you should be good to go.