nRF52840 DK Debugger and USB Detection Issue.

[manoj_patil]

I am experiencing an issue with my nRF52840 DK board. When I initially connect the board to my PC via USB, the debugger LED (LED5) blinks briefly but then turns off. Additionally:

1. The J-Link bootloader does not appear when connected to my PC.

2. The board is not listed as a USB device in the Linux system when I run the lsusb command.

3. The four LEDs connected to the controller are dimly blinking, even though no code is being executed on the board.

I have ensured the USB cable is functional and verified it supports data transfer. I have also tried connecting to multiple USB ports and restarting my PC, but the issue persists.

Environment Details:

Development Board: nRF52840 DK

Host System: Linux Lite

Development Environment: nRF Connect SDK v2.7.0 (Zephyr RTOS)

I suspect there might be an issue with the debugger firmware or hardware, but I am unable to diagnose it further.

Thank you for your assistance!

[Simonr]

Hi

As Jörg says, try reflashing the IMCU firmware. Here's the link to the download page he mentions. Please reach out if this doesn't help.

https://www.nordicsemi.com/Products/Development-hardware/nRF52840-DK/Download#infotabs 

Best regards,

Simon

[manoj_patil]

Hi Turbo J and Simon,

Thank you for your suggestions! I followed the procedure to reflash the Interface MCU firmware as described in the documentation and the link provided. However, the issue persists.

Here’s the current situation:

• The debugger LED (LED5) blinks briefly when I plug in the USB but then turns off completely.
• The four LEDs connected to the controller are still dimly blinking, even though no code is running.
• The board is not recognized as a USB device in Linux (lsusb does not list it).

Thank you for your continued support!

Best regards,
Manoj

[Simonr]

Hi again Manoj

Any chance you can try on a Windows machine for example? It sounds like the issue is still that the IMCU firmware isn't correctly flashed to the debugger, and I haven't heard of anyone using Linux Lite in the past, so I just want to make sure this isn't a OS issue. Did the nRF52840 DK work at one point, but then started misbehaving at some point, or has it been like this all the time. Could you also share the build code of the board (on the white sticker there are three lines of numbers below "PCA10056") that might be helpful.

Best regards,

Simon

[Rahul Chavda]

I am facing the same issue. The LED5 on my DK board blinks for a short time and then turns off. Please find the attached video.