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.

[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

[Rahul Chavda]

ok dear 
my board SOC is work but debugger is not working please help me . how to debugger on. 

[JONATHAN LL]

Thanks for the info, 

Can you try and connect an extra USB cable to the nRF52 USB port? 

Where the arrow indicates. So both USB connectors on the DK is connected to the computer. 

Regards,
Jonathan

[Rahul Chavda]

"We also tried this, but it did not work. Only the SoC is working."

[JONATHAN LL]

Can you measure the voltage on TP35, it is the VDD supply line for the debugger chip. 
SB37 also has access to the debugger VDD. 
https://docs.nordicsemi.com/bundle/ug_nrf52840_dk/page/UG/dk/solder_bridge.html You can se description here, but it can be shorted to bypass the power switch. 



Regards,
Jonathan