The nRF52840 is not being recognized, and LED5 is continuously blinking.

[AjmalAli]

Hi,

I have been using the nRF52840 for a long time, and everything was working fine. However, now LED5 starts blinking whenever the USB is connected to J2. I have tried several methods, such as uninstalling and reinstalling J-Link, but the issue persists.

Additionally, when I press the BOOT button and power cycle the board, I do not see any bootloader folder in the file explorer. I have also tried changing the USB cable, but that did not help.

I am not sure what to do next. Please help me resolve this issue.

Thank you.

[Kenneth]

Hi,

When LED5 blinks rapidly, it often means the board is not being properly recognized by the computer. This could be due to: Faulty USB cables, USB port issues, Power supply problems, Incorrect switch settings (SW9 should be set to VDD). Maybe you have changed some switches or for instance performed some current consumption measurements where you have cut some solder bridges.

If you have already checked those, then maybe you can tell me which nRF52840 DK version you have?

Kenneth

[AjmalAli]

Hi Kenneth,

I have tested with at least four different USB cables and connected the device to multiple laptops. SW9 is set to VDD, and no switches have been changed. In fact, no current measurements have been performed on the development board yet.

Additionally, I am using the older development kit with the PCA10056 onboard debugger, though I am unsure of the exact version.

Thank you.

[Kenneth]

Hi,

Can you try to download and install the latest nRF Command line tools?
https://www.nordicsemi.com/Products/Development-tools/nRF-Command-Line-Tools/Download 

Or nrfutil:
https://www.nordicsemi.com/Products/Development-tools/nRF-Util 

Also install segger j-link, for instance v8.10f (currently required by nrfutil when typing, "nrfutil device --version" in command line)
https://www.segger.com/downloads/jlink 

Make sure to tick off:

If you still have problems, and with all the things you have already tried with cables and hardware switches, there is also the chance the board have been damaged and you need to order yourself a new DK. 

Kenneth

[AjmalAli]

Hi Kenneth,

I followed the mentioned steps, but unfortunately, I was unable to restore the board to its normal condition. However, the code is still running, but the board is not being detected. I'm really not sure what happened to the dev kit, as it was working smoothly before.

Please guide if at all any hardware side need to be fixed.

Thank you for your support.

[Kenneth]

What does the white label on the DK say?

Kenneth

[AjmalAli]

Hi Kenneth,

PCA10056

2.0.2

2021.50

683720887

Please correct me if I am sharing wrong info. FYR I have attached the DK's image.

Thank you.

[Kenneth]

If you press&hold the IF BOOT/RESET during power up when inserting USB cable to the DK, then then you should see a BOOTLOADER drive in Windows, you can try to drag&drop the j-link-ob-sam3u128-v2-nordicsemi-170724.bin you can download from here to see if that helps:
https://www.nordicsemi.com/Products/Development-hardware/nRF52840-DK/Download 

Kenneth