nRF52840 PDK to external board programming

[Labuka]

I'm using the P20 connectors in nRF52 PDK to flash my custom nRF52832 board.

The connections are like this:

SWDIO ----> SWDIO

SWDCLK ---->SWDCLK

VTG ------> VDD

GND DETECT, GND ----> GND

I've powered up the custom board externally. I'll attach a screenshot of the error I'm receiving. Is the connections I've given correct? or Is there any workarounds for solving this problem. nrfjprog is also throwing an error as JLINKARM_DLL_ERROR. 

[ketiljo]

Is the external board powered? The nRF52 PDK does not supply power via VTG so you must supply the board externally. VTG is input to the reference voltage of the level shifters on the nRF52 PDK.

[Labuka]

Yes, the external board is powered by a 3.3v source. So where should I connect the VDD from my external board to nRF52 PDK?

[ketiljo]

VDD should be connected to VTG

Use nRFjprog instead, install the latest version of nRF5x command line tools. 

[Labuka]

I tried using nRFjprog but still that didn't work out. I thought I might have locked out the chip so tried recovery but that also didn't work out. Is there any way to work it out?