nRF52840-Dongle USB DFU problem.

[Hinal Tailor]

Hello

    I want to flash my simple coap server code in nRF52840-Dongle using USB DFU mode with nRFConnect but I did not find COMPORT/ Any Jlink Device after put donge in USB DFU mode. I want to inform you that, accidentally UICR was erased and I need secure bootloader HEX file for Dongle. I also want to know that problem is in Hardware or software because when I am applying 5V to VBUS pin It will not give 3V at D+ and D- pins and internal buck regulator output is 1.8V coming.

Please provide best solution. I need to create openthread mesh network for my application as early as possible because I am working on a sharp deadline project.

Best Regards,

Hinal Tailor

[Hinal Tailor]

Hi Einar

 I have uploaded bootloader HEX file and set UICR . I am getting 3V at VDD_nRF pin but still not getting comport and power on LED also not blink. When I pressed RESET button it will not enter in USB DFU mode and RED led is always blinking.

Thanks,

Hinal Tailor

[Einar Thorsrud]

Hi Hinal,

The LD2  LED will pulsate (soft blink) read to indicate DFU mode. Is that what you see when you say "RED led is always blikning"? How have you validated that it is not in USB DFU mode?

[Hinal Tailor]

Hi

 When I am connecting Dongle with Debugger that time RED LED is pulsating (soft blink) and when I have disconnect dongle from debugger RED LED is continuously blinking. 

I have identify that nRF52840-Dongle is not in DFU mode by not getting any comport in nRF connect to flash the code.

Hinal Tailor

[Einar Thorsrud]

By red LED here you refer to LD2? And that is "hard" blinking red instead of soft blinking red? And the behavior here is dependent on only weather a debugger is connected or not?

[Hinal Tailor]

Hi

  Yes here i refer LD2 red led. Yeah that is "hard" blinking red led. Weather a debugger is not connected.