https://devzone.nordicsemi.com/f/nordic-q-a/9590/nrf51-dk-debug-out-port-connectionsI have a quick question about the use of the nRF51 DK&#39;s Debug Out port (P19) to program external nRF51 boards. The user guide says that the DK will &quot;detect the supply voltage of the board&quot; and then activate P19. The P19 connector has pins marked EXT_VTGen-USTelligent Community 13Tue, 06 Oct 2015 10:43:51 GMThttps://devzone.nordicsemi.com/thread/35418?ContentTypeID=1Tue, 06 Oct 2015 10:43:51 GMT137ad170-7792-4731-bb38-c0d22fbe4515:8054e44f-41b6-40b4-bb86-177b3448ffdaChris<p>Thanks for the link. So the EXT_GND_DETECT pin has no purpose?</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/35417?ContentTypeID=1Tue, 06 Oct 2015 10:41:03 GMT137ad170-7792-4731-bb38-c0d22fbe4515:96d1c294-03e7-4bf7-b42b-da1950b4d12aAlex<p>You don&#39;t need EXT_GND_DETECT. Only only four signals needed <a href="https://devzone.nordicsemi.com/question/42354/programming-other-nrf51822s-using-nrf51-dk/">link text</a></p><div style="clear:both;"></div>