Recover nRF52840 DK after power failure

[rico]

I was trying to measure the current used by the nRF52840 on the DK. But it seems like i have messed up.

• The debugger LED does not light up
• The nRF52840 SOC seems to be okay, since the LEDs are flashing once, which is done in the program i flashed last
• The DK is not recognised from the PC
• If a keep the Reset Button pressed and than power the DK, the LED starts blinking with arround 1Hz, but is still not recognised from the PC
• Switch states
  • SW10 Off
  • SW8 on
  • Power from USB
  • SW9 VDD
  • SW6 default

What have i done:

I connected a 3.0V power supply to the external supply header, i switch SW6 to nrf Only, SW9 still in VDD and SW10 On. Since it is recommend in the DK manual to power the debugger chip aswell i connected the dev kit via USB to the PC. So the DK itseld should be powered via USb and the nrf is powered via the ext. supply pins.

Any idea how to fix the dev kit? How to do it right?

[rico]

I just recognised, in the case i press the reset button while powering thr DK, it is recognised as a USB Flash device only, named BOOTLOADER. Is there a way to use this to reprogram it?

[Bjørn Kvaale]

Just download the interface MCU FW for J-Link here & drag & drop it to the Bootloader drive. You can then reset the kit & you should see it appear as a JLINK drive again.

[Venkat]

Hi Bjorn I am a student and I need your help How Can I contact through personal message

[Bjørn Kvaale]

If you have an issue, I recommend first looking through DevZone to see if you can find a similar case to the one you are looking for or by opening up a new DevZone case here.