nRF52 DK use P20 to program an externally powered board @ 3.3V

[engrns]

Hi there 

I have nrf52 DK - PCA10040 which I believe contains nRF52832 IC

I have designed a new PCB that contains BT832 (nRF52832) module from Fanstel

My board is powered from 4V DC & has on-board voltage regulator of 3.3V for BT832 (nRF52832)

I am planning to use the header P20 on nRF52 DK to program my board (whilst my board is powered from its own 3.3V)

My nRF52DK is powered from the USB (I am not using its own coin cell)

I understand that I need to connect:

                        

My board	nRF52 DK (Header P20)
SWDIO	SWDIO
SWDCLK	SWDCLK
GND	GND DETECT (& then a link to GND (on say P13)
3V3	Where do I connect this?

Any help would be greatly appreciated

Kind Regards

[Stian Røed Hafskjold]

Hi, you connect it to the VTG pin.

[engrns]

Thanks for the feedback. 

Do I leave VDD & VDDnRF pins on header P20 unconnected? (These are pins 1 & 2 on this header)?

And I am assuming I would also need to connect a link on SB10 to bypass the diode?

Kind Regards

[Stian Røed Hafskjold]

Yes, you can leave the VDD and VDDnRF pins unconnected. These are for powering the nRF52832 on the PCA10040.

You can bypass the diode to get the voltage closer to the target voltage, but I think you're fine without as well. The SWDIO/CLK voltage will be around 2.9V with the diode.