nrf51422 bricked (N5 Starter Kit from Dynastream)

RE: nrf51422 bricked (N5 Starter Kit from Dynastream)

Asbjørn — Tue, 11 Nov 2014 12:05:27 GMT

I'm glad you figured it out and we really appreciate that you took the time to update this case with the additional information and the solution. Thank you for helping the forum.

RE: nrf51422 bricked (N5 Starter Kit from Dynastream)

Jens Meder — Mon, 10 Nov 2014 15:19:37 GMT

Hi Asbjørn,

thanks for you reply. After a lot of trial and error we have found the issue: it was indeed the VDD. Unfortunately, it has been obfuscated by some non obvious characteristics of the Dynastream Devkit. In case someone runs into the same issues, here is the solution:

The voltage of the 3.6V coin cell has dropped below 1.7V due to discharge that made it impossible to flash new code to the nrf51422 chips. When we mounted the chips to the usb dev board the voltage was at around 3.5V as measured via J-Link. What we didn't now: The usb dev board that comes with the N5 starter kit blocks the J-Link interface. The chip is fully operational but you simply cannot flash any code on it while mounted on the usb board.

Bottom line is that you can only flash the chips while mounted on the battery board. So you either have to solder some headers to the battery board and use an external power source or buy some rechargeable coin cells.

RE: nrf51422 bricked (N5 Starter Kit from Dynastream)

Asbjørn — Fri, 17 Oct 2014 07:45:07 GMT

It sounds like there might be an issue with the voltage on the chip, especially since you've experienced some difficulties programming it previously as well. The J-Link requires 3.3 V to function properly and if you use a different voltage you might end up with some similar behavior. It all depends on how far away from 3.3 V you are. Usually 3.0 V works fine. So I don't know if you have been running the board and programming it at a much lower voltage? Using a coin cell of 3.0 V should not be a problem, so I would use this until you have recovered it now.j-link commander, nRFgo studio or nrfjprog all should be able to recover this board as long as the voltage and the j-link is working correctly.

Secondly, it could be a header or a connection that's not in place. Could you check the VDD of the nRF51422 chip? Is it actually the voltage you think it should be?

Do you have other boards that you could try the programmer on? It would be nice to know that the programming routine/drivers are all working correct.

If none of the above is working, please try to re-install the various software components needed such as the drivers for j-link and nRFtools.