nRF52840 Dongle Bricked After Programming

[RodWatt]

Hi,

I have a nRF52840 Dongle connected up to an external j-link debugger. I have been using this over the past few weeks with no issues and unfortunately I have managed to brick it. 

When I try to connect, i get an error saying that no board is connected. I have tried nrfproj from a comment line, the j-link lite tool and the nRFconnect programmer, all complain that they can not see the dongle.

(Actually, I had managed to do this on two separate dongles, on one the green LED remains permanently lit and on the other, there are no leds lit)

This issue seems to be similar to what Im seeing

https://devzone.nordicsemi.com/f/nordic-q-a/39596/the-nrf52840-dongle-can-no-longer-be-accessed-after-flashing-hex-file/153553#153553

Here the answers was to use the reset button. I have tried pushing, holding. tapping the reset with no changes.

How can I bring the boards back to life?

Thanks,

Rod 

[Jared]

Hi,

This is probably due to the UCIR being deleted. The J-link lite supports only a target voltage of 3.3 V while the GPIO voltage (REG0) is by default 1.8 V on the nRF52840. The solution would be to use a debugger that is able to program down to 1.8 V volt. Other solutions are suggested in our programming dongle tutorial.

best regards

Jared 

[RodWatt]

Hi Jared,

I have checked the tutorial again. Looking at the section 

Recover after an accidental UICR erase

You have two options for recovering when the REG0 (VDD) voltage is 1.8 V (typically after a UICR erase):

• Either use a debug probe that adapts the logic levels to the target device (for instance a J-Link PRO). Program firmware that configures REGOUT0 for 3 V.
• Or modify the dongle so that it can be supplied by an external supply and use the nRF52840 DK to program it.
  1. Adapt the dongle hardware as described under External regulated source in the nRF52840 Dongle documentation.
  2. Connect VDD from the nRF52840 DK to VDD OUT on the nRF52840 Dongle.

I am using a j-link plus.

I have modified my board so I am powering it from a 3.3V supply to VDDOUT.

I still am unable to connect to the board

Rod

[Jared]

Hi,

Thanks for the log. The DEC pins as marked in the schematic below:

[RodWatt]

Thanks, sorry, I was looking at the pins around the board itself.

DEC1 - 0.8V

DEC2 - 1.2V 

DEC3 - 3.3V

DEC4 - 1.2V 

DEC6 - 1.2V

 

[Jared]

Thank you. The DEC pins are ok. I'm suspecting that the RESET pin is held low. What voltage do you see over C27?

[RodWatt]

0V

[Jared]

Ok, this would explain the behavior that you're observing. The chip is kept in reset state due to the reset pin being pulled low. Could you try shorting R2 which would result in the reset pin being pulled up to VDD? And then run a recover command with a debugger that supports 1.8 V. Just make sure that the reset pin isn't pulled down by something externally first. 

[RodWatt]

Hey Jared,

Yes!! That worked, thanks. I am now able to program the dongle again. Any thoughts on how I could have got in that state? Just so I can avoid next time.

Rod

[Jared]

Hi,

Great!

Not sure why but if it wasn't pulled down externally then maybe it was in your application or during the programming/erase of the dongle. 

regards

Jared 

[Ivo H]

Dear sir, I am facing similar issue. I used openOCD to debug dongle with Eclipse but I experience some problems not being able to run my code on the dongle when when pressing build in Eclipse. Nevertheless after removing the dongle from my Raspberry, the LED on dongle started to flash RED that looked ok, bot the openOCD offered to to enter command nrf52_recover. After this command the dongle stopped working. I probably erased the firmware which must be recovered with probe. But I am experiencing voltage 2.9V on C27,does that mean it could still be recovered? In this post the guy had 0V cross C27.Thank you