https://devzone.nordicsemi.com/f/nordic-q-a/74061/minimum-programming-pins-using-jlink-jtag-for-custom-nrf52-boardsHello, My goal is to use the Jlink JTAG for programming custom nRF52 boards (specifically, nRF52840) using minimum number of wires. The default Jlink JTAG is a 20pin connector, or it can be reduced to 10 pins using an adapter. From what I read, allen-USTelligent Community 13Fri, 16 Apr 2021 03:10:25 GMThttps://devzone.nordicsemi.com/thread/305190?ContentTypeID=1Fri, 16 Apr 2021 03:10:25 GMT137ad170-7792-4731-bb38-c0d22fbe4515:646facba-2781-4afe-83e8-bef276af0d40Nguyen Hoan Hoang<p>Does it work when you use the PCA10056 to program the Dongle ? If it doesn&#39;t, check for broken&nbsp;cable.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/305189?ContentTypeID=1Fri, 16 Apr 2021 03:05:34 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bbb3175e-b852-4e9c-81ec-f4e0d22834d4mrsunny<p>As confirmation, I tried programming the nRF52840 development board PCA10056, as well as the <span>nRF52840&nbsp;dongle&nbsp;</span>using the JTAG pin config&nbsp;of only wiring the VCC, GND, SWDIO, and SWDCLK pins. No luck.</p> <p>This is what I connected to the JTAG on the nRF52840 dongle. The dongle was powered on by inserting it to my computer&#39;s USB port. The same problem appears that the JLink does not recognize the board.</p> <p><br /><img src="https://devzone.nordicsemi.com/resized-image/__size/320x240/__key/communityserver-discussions-components-files/4/nrf52_2D00_dongle_2D00_swd_2D00_pins.PNG" alt=" " /></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/305187?ContentTypeID=1Fri, 16 Apr 2021 02:04:14 GMT137ad170-7792-4731-bb38-c0d22fbe4515:cf9cebbf-9d5c-4a17-a161-e06db1fe55a1Nguyen Hoan Hoang<p>I seems that your custom board isn&#39;t working. Have you tried on other board?</p><div style="clear:both;"></div>