Nrf52840 dongle cannot enter reset mode

[Geass77]

Dongle cannot enter reset mode, and led  is not pulsing(no shine ) when I  connect to PC, the device cannot detect it,too. Is their any problem on the firmware, the device cannot detect it,too. Is their any problem on the firmware, or it was just broken?

[Amanda Hsieh]

Hi, 

The simplest way to program the dongle is to use the nRF Connect for Desktop and launch the Programmer app:

1. Open nRF Connect for Desktop and launch the Programmer app.
2. Press the reset button to put the Dongle in DFU mode. This is not needed if the currently running application uses the DFU trigger library. Note that the reset button is the sideways button right next to the more obvious SW1 button on the Dongle:
   
3. Select the dongle in the dropdown in the upper left corner if it is shown.
4. Click "Add HEX file" to select the application hex file to program onto the dongle.
5. Click "Write" to write the firmware to the dongle.

Please also see this tutorial. 

-Amanda H.

[senthil_kumar]

Hi 

Amanda Hsieh said:

Have you soldered and connected an external debugger, and erased all flash(including bootloader)?

Yes, here I am erased all the flash (including bootloader). 

And I tried this link /cfs-file/__key/communityserver-discussions-components-files/4/1643.pca10059_5F00_bootloader.zip

But nothing happened after flashing the bootloader, so what can I have to do to recover the bootloader?

[Nguyen Hoan Hoang]

try this one instead sourceforge.net/.../

[senthil_kumar]

Hi

Thanks for your response.

 I already tried three types of HEX files but no response. But before I set the UICR register value for REGOUT0  setting 3.3v.

1234.pca10059_bootloader_mbr_v1.0.1.hex  

4331.graviton_bootloader_mbr_v1.0.1-[nRF5_SDK_15.0.1-1.alpha_f76d012].hex 

1727.nrf52840_xxaa.hex

After bootload, nrf52840_Dongle LD2 red led rapidly blinking toggling every 100 ms, Whenever the debugger is not connected, That time comport also not showing in nRF connect. 

If a debugger is connected to a dongle the LD2 red led is soft blinking (Breathing).

Thanks & Regards

Senthil Kumar

[Amanda Hsieh]

Hi Senthil, 

Please create your own case. This case was updated one year ago, and it seems related to this case https://devzone.nordicsemi.com/f/nordic-q-a/75142/nrf52840-dongle-usb-dfu-problem.

-Amanda H. 

[senthil_kumar]

Hi Amanda,

        Sorry for that, I thought this case was not completed,  that's why I replied to this case.  

Amanda Hsieh said:

Please create your own case

 Yeah sure.

  Thanks.