NRF52840 Dongle doesn´t work.

[p143]

I have several 5 years old nRF52840 dongles. With one of them, when I connected it to nRFConnect for PC, the led doesn´t shine at all, and no device is detected. When I try with another nRF52840 dongle (which in this case, hasn´t been used before),  the led gets permanently flashing, butagain, is not bein recognized. I am working with W10. What could be the problem? Maybe the driver got old? Thanks

[Edvin]

Hello,

On the dongle that doesn't work, can you try to plug it into the computer, and then press the reset buttton (Please note that this is not the big white button on the dongle, but the small grey sideway button right next to it, marked "RESET" on the PCB. Does it start flashing the red LED (or more like a breathing pattern)? If not, did you ever program this dongle with anything other than our software tools? Did you program it with an external debugger at some point? In that case, you may have removed the pre-programmed bootloader that should kick in when you press the RESET button while the device is powered.

Best regards,

Edvin

[p143]

Hi Edwin.

Now, the faulty dongle is also "breathing," but still, both are not recognized by nRFConnect for PC. Remember that one of them is out of the shelf (so it was not yet ever flashed). Both dongles were bought over five years ago, but the Connect app version has just been just updated. I barely remember that in the past, I often had this same problem and that your colleagues were sending me some firmware to flashback into the dongle to repair it. Does this give you some clue on where the problem could be? All I want is to practice monitoring RSSIs from some peripherals and remember how to flash firmware inside the dongle SoC. Thank You, and best regards.

Juan

[Edvin]

p143 said:

I often had this same problem and that your colleagues were sending me some firmware to flashback into the dongle to repair it.

Was that on the dongle that is no longer working, or another dongle? And how did you flash it to your dongle? nRF Connect for Desktop -> Programmer, or something else?

In case you programmed it using an external debugger, does it behave as expected with the debugger connected to it?

The fact that it is "breathing" red suggests that it has the bootloader still present on it. Does it appear if you try to open nRF Connect for Desktop -> Programmer while it is breathing red?

Best regards,

Edvin

[p143]

Hi Edwin.
I bought all the Dongles more than five years ago, but only one has been used. Regarding this one, when I reset the Dongle whose LED isn't working, it begins to breathe, as it should, but if I unplug and plug it back to ther PC, the LED does not bright back until it gets reset again.
Regarding the second Dongle, I never used it at all, and its led behaves as you told me, "breathing red".
The problem is that, none of them gets recognizd ny Connet for PC, nor advertise their Local Name to my mobile Connect app, which is what I need (to measure RSSIs). I also need to practice programming from Connect for PC to the Dongle.
In the past, I used to have this problem, and I barely remember that your colleagues were sending me some peace of sw that I had to re-program in the Dongle, solving the problem.
Do these comments suggest one solution to you? Thanks
Regards
Juan

[Edvin]

Hello Juan,

This is expected behavior. If an application is programmed onto the bootloader, then it will start that application whenever it is powered. If you press the reset button, it will enter DFU mode (red breathe). But if nothing new is programmed to it, then it will jump right back into the application after a power cycle. Only if no application is present, it will jump directly into DFU mode when you power it. 

p143 said:

nor advertise their Local Name to my mobile Connect app, which is what I need (to measure RSSIs)

They will not advertise anything, unless they are programmed with an application that tells it to start advertising. 

Can you show me a screenshot of what it looks like when you have the dongle in DFU mode, and you open nRF Connect for Desktop -> Programmer:

If it doesn't show up as "Open DFU Bootloader", can you please try another USB port on your computer? And if you are using a USB hub, can you try to plug it directly in the computer instead?

Best regards,

Edvin