NRF52840 DK Board not working

[Rahul Chavda]

I have an NRF52840 DK (3.0.2) board, but it is not working. The USB port is not detected. When I power it through USB, the debug LED (LED5) turns on and then off. On the SoC side,

LEDs 1, 2, 3, and 4 are dimly lit. Please help and provide a proper solution.

[JONATHAN LL]

Was this a brand new DK ?

Did it work at some point that you are aware of?

Have you tested different USB cables? 

VEXT should be in OFF position. 


It also looks like this DK has been modified with extra pins on the sides, make sure that there is no shorts VDD and GND or 5V or GND or any of the GPIO pins.  

Regards,
Jonathan

[Rahul Chavda]

I also tried changing the USB cable, but it is still not working.

I checked by turning off the VEXT pin, but it didn't work either.

I have checked the 5V and GND, and they are fine. I also checked the nearby pins where I connected external components, and there are no shorts anywhere.

[JONATHAN LL]

Do you have another DK available or a debugger?

You can connect to the Debug In connector and see if the nRF52840 SoC still works. If so then there is a issue with the onboard debugger. 

LE5D5 on your DK also does not seem to be glowing, so maybe the Debugger chip is disconnected or damaged. 

Is the SW1 Flow control switch on the ON position ? 


Also try to wiggle or change the position of the SW9, and then go back to the middle position, VDD power. If the switch is in USB or LiPO position then all LEDS will blink\glow softly. 

Regards,
Jonathan

[Rahul Chavda]

Yes, I have another DK board.
The SW1 flow control switch is ON on the board.
I also tried changing SW9, but LED5 only blinks and then turns off.

[Rahul Chavda]

I am facing the same issue. The LED5 on my DK board blinks for a short time and then turns off. Please find the attached video.

[JONATHAN LL]

Can you use the Debug out port from the other DK to program the nRF52840 on the DK that does not work as expected?



You can use a 10-pin ribbon cable connector here and try to program the nRF52840, if there are no issues with that then its likely that there is something wrong with the debugger chip and circuitry.

Regards,
Jonathan