NRF52840-DK Jlink detection failed

[KLui]

Hi, I used my NRF52840-DK for few times but suddenly the jlink connection was not detectable. Before the Jlink failed, the main controller on board did not bring up the board properly after switching on/off the power switch. USB connection was running after a reset on the main controller. I think the board needs reloading the firmware. Please provide me the procedures how to do it without a programmer. Thanks.

[Einar Thorsrud]

Hi,

To re-flash the onboard debugger push and hold the reset button while power cycling the board. Then you should se LED 5 start blinking slowly to indicate that the onboard debugger is in DFU mode, and you should see a removable mass storage device on your computer named "BOOTLOADER". Download the Interface MCU firmware from here and drag and drop it to the BOOTLOADER drive. After a while power cycle the board.

[KLui]

Thanks.

[Elias Bruggmann]

Hi

I have the same problem, but my BOOTLOADER drive is too small for the J-LINK firmware. What could be the reason for that?

[Einar Thorsrud]

Hi,

That should not be the case. Can you explain in more details? Which sized do you see for the BOOTLOADER drive and for the J-Link firmware? And what happens when you try to copy it over?

And just to be sure that it is in the correct mode, can you check which files are there in the BOOTLOADER drive? You should see a file named bootload.htm.

[Elias Bruggmann]

Thanks for your fast reply

Yes I can see that file. Size of the J-Link file is 108KB. Size of the BOOTLOADER drive is 128KB but 28KB are used, so its 100KB. The error I get is this:

 

PS. Board Version is 2.0.1

[Einar Thorsrud]

That is odd. I will try to get hold of a 2.0.1 device and test on that, though it should not matter. Are you able to recover using the J-Link Configurator instead?