https://devzone.nordicsemi.com/f/nordic-q-a/11638/nrf52-pin-connection-with-6-pin-j-linkCan the nRF52 be programmed by 6-pin J-Link Adapter by just connecting the following 4 pins, Pin 1 : 3.3v Supply, Pin 2 SWDIO, Pin 4 SWDCLK, Pin 5 GND, Can pins 3 &amp; 6 of 6-pin J-Link Aapter be left unconnected or do we need to have some pullen-USTelligent Community 13Sun, 31 Jan 2016 14:09:21 GMThttps://devzone.nordicsemi.com/thread/43984?ContentTypeID=1Sun, 31 Jan 2016 14:09:21 GMT137ad170-7792-4731-bb38-c0d22fbe4515:86bc6df2-ee84-4ac6-9170-f775a93222caAmigo<p>PCA10040 uses 10 pin Debug Connector (P18). There are 2 additional pins P0.18 &amp; P0.21 besides the SWDIO &amp; SWDCLK. Do you mean that P0.18 &amp; P0.21 can be left unconnected?</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/43983?ContentTypeID=1Sun, 31 Jan 2016 09:59:07 GMT137ad170-7792-4731-bb38-c0d22fbe4515:64a45e64-9d5f-472c-bebc-1789c7beb258RK<p>Yes you only need to connect those 4 pins - if you look at the circuit diagram for the PCA10040, which is the dev board for the nRF52, you&#39;ll see what exactly is connected to which pins of the on-board ARM header - just follow that and you&#39;ll be fine.</p><div style="clear:both;"></div>