Device Manager not showing nRF52840 Dongle

[faskrobo]

I got an nRF52840 Dongle from someone else and started to see what I could do with it. The problem is, although I've downloaded everything needed including nRF Connect on Windows 10, the dongle doesn't show up in Device Manager, or in nRF Connect Programmer, Segger, or VS Code. When I plug it in, LD2 blinks blue at first and then switches to blinking red, while LD1 blinks green more slowly. Does this mean it's in bootloader mode?

I'm new to nRF devices and also J-Link somewhat, so I'm not completely sure my understanding of what to do is correct yet. Is there anything else I can do to get the USB interface working or do I need to re-flash the bootloader over SWD? If the latter, I don't currently have the male pin header for the P1 footprint on the bottom of the device, so would I be able to instead solder the SWDIO and SWDCLK to wires that connect to the proper pins on a J-Link, and use the USB interface for VCC and GND?

Finally, I saw in the bootloader documentation that nrfjprog or Segger can be used to re-program memory. So if I need to re-flash the bootloader, should I connect the device over USB and SWD as described above and use Segger or the following command to flash the .hex file? Is there anything I'm missing?

nrfjprog --reset --program application.hex --family NRF52 --sectoranduicrerase

[Elfving]

Hello,

As Austin944 mentioned, you can use sideways button to enter bootloader mode. Though as you have gotten it from someone else, it might be that they have already flashed something to it that has removed the MCUBoot partition. With the bootloader present however, it should be possible to flash it using the nRF Connect Programmer while it is in bootloader mode. Using VSC and SES doesn't work, as they would need an external programmer which the Dongle doesn't have. For those reasons the Dongle can be a bit hard to work with, so I recommend that you give this blog post on how to work with it a read. 

Does this mean it's in bootloader mode?

No, in bootloader mode LD2 would slowly blink red.

It might be that you would have to re-flash it using the external debugger on another DK, with SWD. Though first of all, are you getting it to enter bootloader mode? And if so do you see it in the drop-down menu in the nRF Connect Programmer?

Regards,

Elfving

[austin944]

The nRF connect programmer supports both the DK and the Dongle. If you have kept the Reset button pressed while inserting the Dongle into the USB port and you don't see the red LED slowly flashing after releasing the button, then either the bootloader is gone from the Dongle, or the Dongle itself has some hardware problem.  If the bootloader is gone, then you will need an external programmer like the j-Link.

[faskrobo]

Ok that makes sense. The thing is I don't have a pin header right now, so while I'm waiting for one to arrive I'm thinking of soldering wires to the two SWD notches and connecting them to the CLK and IO pins of the J-Link as I described previously. Would that work? And would I be able to see the dongle on Segger or VS Code while it's connected to the J-Link?

[austin944]

Connecting the j-link to the SWD pins should work.  You will need to provide power to the Dongle, either over USB or using the j-link connector.   Once the j-link is connected to your PC, the nRF connect programmer should see it and will you be able to select the j-link in the connect programmer.