Problem with J-link edu mini and NRF52 Dongle software loading

RE: Problem with J-link edu mini and NRF52 Dongle software loading

dragilla — Wed, 12 May 2021 12:23:31 GMT

I know, I pasted this link in the original post :) I did this accidentally while soldering the debug connector.

RE: Problem with J-link edu mini and NRF52 Dongle software loading

Amanda Hsieh — Wed, 12 May 2021 12:10:43 GMT

See External regulated source

CAUTION:

Do not have both SB1 and SB2 connected at the same time as this will damage the nRF52840 SoC.

-Amanda H.

RE: Problem with J-link edu mini and NRF52 Dongle software loading

dragilla — Wed, 12 May 2021 11:58:33 GMT

Thank you for your answer. The dongle is clearly broken :( I can still use it through nRF Connect or through J-Flash Lite but starting an app through uVision and viewing logs through RTT rarely works (sometimes it does, but it's not clear why and when).

The SB1 and SB2 were soldered at the same time for a while and I think it broke it. Now I desoldered SB1 but it doesn't help. So for now I think there is nothing I can do?

RE: Problem with J-link edu mini and NRF52 Dongle software loading

Amanda Hsieh — Fri, 07 May 2021 11:04:10 GMT

Hi,

This seems a bit chaotic, so I am not sure about everything. But first of all, the fact that you sometimes need to program via the nRF Connect programmer app makes sense. The bootloader will check bootloader settings for a CRC and flag indicating that the app is valid. So if you keep the bootloader but don't update the bootloader setting (which happens automatically during a USB DFU), then the bootloader will not start the app, but enter DFU mode. Also, the bootloader in the dongle will enter DFU mode if there has been a pin reset. Could it be that you modified HW tampers with the reset line? You may be seeing both these two issues at different times.

-Amanda H.

RE: Problem with J-link edu mini and NRF52 Dongle software loading

dragilla — Fri, 07 May 2021 10:06:53 GMT

Ok. I think I know what I did wrong. I accidently soldered the SB1 bridge next to the SWD connector.

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fug_nrf52840_dongle%2FUG%2Fnrf52840_Dongle%2Fhw_power_supply.html

It worked for a while and something failed as a result. Can you guess what could have happened and if I can fix it?

I desoldered the bridge but my the problems remain.

RE: Problem with J-link edu mini and NRF52 Dongle software loading

dragilla — Thu, 06 May 2021 08:03:01 GMT

Ok. Another observation - finally a pattern.

When I stop the RTT connection - then I can program via uVision and the program start afterwards. But then there is a problem to connect to RTT again. because it works only 1 in 10 tries. The other 9, I get the annoying blinking red led.

PS: another observation: when RTT viewer is connected and I take the dongle out, the red led on the dongle keeps blinking... like the dongle is powered via the debugger? I think this is causing the problem. I only don't understand how this could have worked from the beginning...

Maybe I connected my debugger in the wrong way from the begining and now something has broken?

Please advise, thanks

RE: Problem with J-link edu mini and NRF52 Dongle software loading

dragilla — Wed, 05 May 2021 21:06:21 GMT

After such unsuccesful floash download in uvision, build log says:

Erase Done.
Programming Done.
Verify OK.
Flash Load finished at 23:04:07

And then in nRF Connect - Programmer I can see only the bootloader - the application was not loaded :(