nRF52840 Not Detected by nrfjprog / Recover Fails - Need Expert Advice

[veelox321]

• • Hello,

    I'm having a serious issue with my nRF52840 board.
    Here’s what I already tried:

    ---

     What I have done:

    • Verified working USB cables (data + power).

    • Installed SEGGER J-Link drivers.

    • Installed nRF Command Line Tools (latest).

    • nrfjprog --help works fine.

    • Installed Zephyr SDK and built a simple hello_world project.

    • Tried west flash and nrfjprog --recover. 

    • Installed J-Link Configurator (no device shows up).

    • Tried multiple USB ports and cables.

    • Tried flashing with Arduino IDE — still no COM port.

    • Windows sees the device only as "USB Device" (driver missing). now it wont see it at all

    ---

     Current problem:

    • nrfjprog --recover gives:
      ERROR: No debuggers were discovered.

    • No COM port appears.

    • No J-Link detected.

    • Board only makes a USB connection sound when plugging in (sometimes). now not at all

    ---

    ---

    Thanks for your help! 
    I would like to try everything possible before giving up.

[Edvin]

Hello,

I'm having a serious issue with my nRF52840 board

Is that an nRF52840 DK, or is it a custom board?

If it is an nRF52840 DK:

1: You are using the USB connector on the short side of the DK, right?

2: If you already are, and the device is powered, can you please take a closeup of the DK, so that I can check the various switches on the DK, and see if they are all in the right state?

3: Have you tried another USB cable, to make sure that the cable is not broken, or that you are accidentally using a charging cable, which doesn't have data lines (only power)?

If you are using a custom board:

1: How do you connect it to your computer? Do you have an external debugger? How do you connect it?

Best regards,

Edvin

[veelox321]

Hi, i am unsure about the model, since im not the one who bought it but i think it is an adafruit feather nrf52840 express (https://www.digikey.ca/en/products/detail/adafruit-industries-llc/4062/9843410)
1 - i use the only usb available 

2 - There is no switches

3 - i have tried others usb cable, im confident they are data cable since it is working on other mcu

4 - i use an swd programmer i had the max32625pico which seems to work

thanks

[Edvin]

Ok. So this is a 3rd party device, that comes pre-programmed with a bootloader, that you can probably use to upload new applications using the Arduino IDE or something.

If you have used an SWD programmer on it before, you may have deleted the bootloader on the device. If that is the case, you will no longer be able to program it using the USB cable. First, you would need to program a new bootloader. I guess you can reach out to Adafruit and ask where you can find the original bootloader for this device. 

But if you have an external programmer, you don't need a bootloader either. You can simply program the device using the programmer instead.

Best regards,

Edvin