https://devzone.nordicsemi.com/f/nordic-q-a/20705/program-custom-board-using-j-link-eduI&#39;m facing problem while program custom board. I&#39;m using nrf51822 module( link ) &amp; j-link EDU 9.3 version. I think there is some connection issue. Here is my connection J-link----------------nrf51822 VTnrf----------------VDD GND-------------en-USTelligent Community 13Thu, 23 Mar 2017 10:24:11 GMThttps://devzone.nordicsemi.com/thread/80773?ContentTypeID=1Thu, 23 Mar 2017 10:24:11 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b449eac8-5000-4735-9080-e84024ad9a2cHung Bui<p>No you don&#39; t need pull up. If the chip is revision 1 (very less likely, check the revision <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf51/dita/nrf51/compatibility_matrix/nRF51822_ic_revision_overview.html?cp=3_0_1">here</a>. ) you would need pull down on SWDCLK.</p> <p>Made sure you provided 3.3V to nRF51822 and that is connected to VTref.</p><div style="clear:both;"></div>