Nrf52840 Dk disable u1

[Giovanni De Rosa]

Hi,
I need to program my custom boards, i am using nrf52840 DK which switches programming from the internal chip to the external one based on its presence.

Is it possible to remove/disable/U1 so that in case of false contact the internal chip is not programmed but nrf Connect for desktop gives error ? 

[Priyanka]

Hi,

Yes, it's possible to use the DK to program external boards and not the internal SoC, if this is what you are asking for. Please take a look at the following documentation and hope it helps:

https://docs.nordicsemi.com/bundle/ug_nrf52840_dk/page/UG/dk/hw_debug_out.html#ariaid-title1 

Regards,

Priyanka

[Giovanni De Rosa]

Strange I had already short-circuited SB47 to power the external board but still managed to programme the internal soc.
I solved it by shorting the pins as in the picture by locking SWDIO. 

can it cause problems?  

[Priyanka]

Hi,

Yes, that is strange that you are able to program the internal SoC even after shorting SB47. Could you re-check your connections? Because there have been instances where users using cables and not pin connectors faced similar issues when they connected wrong.

Giovanni De Rosa said:

I solved it by shorting the pins as in the picture by locking SWDIO. 

Well, if it works for you then I guess it should be fine, but we would not recommend permanently pulling an SWDIO pin high or low as you could loose functionalities/features.

-Priyanka

[Giovanni De Rosa]

the custom board side connector is composed as follows