https://devzone.nordicsemi.com/f/nordic-q-a/28638/unable-to-connect-to-nrf52840-via-swdHello, I&#39;m playing with nRF52840 on a custom board, trying to connect to the chip via SWD. Segger Flasher is being used, on MacOS. Typically I was able to connect to the board via JLinkExe like this: SEGGER J-Link Commander V6.20g (Compiled Octen-USTelligent Community 13Thu, 02 Aug 2018 15:52:50 GMThttps://devzone.nordicsemi.com/thread/142682?ContentTypeID=1Thu, 02 Aug 2018 15:52:50 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c2415dde-c3d3-4954-a25f-18ffb5c64ea4Nopik<p>The faulty board was repaired, and all N boards are OK for long time. I&#39;m not sure what was fixed there, probably one element was replaced (I think it could be either CPU itself or some DC/DC converter, we had problems with those at the beginning, purely due to faults in our design). Our early boards had a bug of not having VDD/VDDH connected properly, this issue happened on one of those boards, we&#39;ve corrected the bug later on.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/142679?ContentTypeID=1Thu, 02 Aug 2018 15:47:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:19b3d530-6158-4b6a-8708-eed87aa8e6baVincent Bela&#239;che[quote userid="26952" url="~/f/nordic-q-a/28638/unable-to-connect-to-nrf52840-via-swd/142671"]and I&#39;m working with it constantly since then)[/quote] <p>Do you mean that you had N boards, N &gt;1, only one is broken, but you are working constantly with the N-1 others since then?</p> <p>Or do you mean that you could repair the board for which the faulty case happened ?</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/142671?ContentTypeID=1Thu, 02 Aug 2018 15:36:11 GMT137ad170-7792-4731-bb38-c0d22fbe4515:26e098ba-756a-4fe7-866c-975f3b5d3af3Nopik<p>Vincent, I don&#39;t think this is the same issue. It happened for me only on one board, months ago (and I&#39;m working with it constantly since then), and most likely was a faulty hardware problem.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/142668?ContentTypeID=1Thu, 02 Aug 2018 15:23:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:470bc038-2538-461d-8941-55b2c736531cVincent Bela&#239;che<p>Hello @Nopik &amp; @Matt. Have you found any solution ? We have a similar issue: in our case the SWD seems to be OK before the board goes to some &laquo; <span>Could not power-up debug power domain&nbsp;&raquo;</span>&nbsp;(hereinafter ERROR) state. The ERROR seems to be caused by having flashed some FW. After the ERROR state&nbsp;occurring, not only we cannot connect any longer to the NRF52840 by JLinkExe, but as for Nopik&#39;s case &laquo; nrfjprog --recover &raquo; does not help&hellip;</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/113510?ContentTypeID=1Mon, 18 Dec 2017 14:55:14 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f6299b23-6a33-4d67-aa65-7cdd0d7e391cMatt<p>Can you probe the SWD and SWDCLK lines to see if there&#39;s any activities at all there? I&#39;m no h/w dude so I cannot tell you what to expect when you probe those lines, but hopefully there&#39;s something there!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/113509?ContentTypeID=1Mon, 18 Dec 2017 14:43:48 GMT137ad170-7792-4731-bb38-c0d22fbe4515:902403e7-5d2e-403f-b94f-158c41d7fc08Nopik<p>Sadly, not at the moment.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/113508?ContentTypeID=1Mon, 18 Dec 2017 13:51:41 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2280d1bc-cd7d-48c3-94a5-4b0935492ce0Matt<p>Do you have another custom board to test with?</p><div style="clear:both;"></div>