Bricked nRF52840-dk

[Jerry Easley]

I had a pathological application running of my nRF52840 so I reset/power sequenced it; that procedure got rid of the pathological program but it also broke JLink, I think.  In any case it now connects as a usb serial device.  Apparently I need to reflash it in order to restore functionality,  There are other tickets on here concerning this issue and which I have reviewed.  I found the restorative procedures posited there to be incomprehensible; I am a newcomer to Nordic an I am not at all familiar with the tools used to do this,  So I need instructions in great detail.

Regards,

Jerry

[Simonr]

Hi Jerry

SW10 sets whether you want to use an external power supply for the nRF or not. If you only power the nRF by the nRF USB header it will need to be set to ON, but can be set to OFF if you want to power it from the J2 debug connector.

What connector are the USB cable connected to your DK on here?

Glad to hear you seem to have figured it out. Antivirus software can cause issues like this indeed, so I assume this is what you're having trouble with. Let me know if that's not the case.

Best regards,

Simon

[Jerry Easley]

There are two usb connectors, one on the narrow edge of the board and which seems to be unlabeled and one on the wide side of the board and which is labeled “nRF USB”.  Initially, I only used the unlabeled port; that is the port that has the debugger connected to it. This worked fine until i implemented a ACM console which requires the nrf usb port be connected. 

I’m pretty sure I’ve found the culprit, now all I have to do is get Avast to fix it.  In any case I’m convinced the board is functioning correctly.

Regards,

Jerry