https://devzone.nordicsemi.com/f/nordic-q-a/48747/seggar-embedded-studio-can-recognize-the-nrf52840-development-board-but-not-the-external-device-debugging-targetHi, I&#39;m trying to use the Seggar Embedded Studio to debug my code, but the Seggar Embedded Studio can only recognize the nRF52840 development board, not the external device that I need to debug, even though the device is definitely powered up. I can useen-USTelligent Community 13Wed, 19 Jun 2019 07:32:39 GMThttps://devzone.nordicsemi.com/thread/193550?ContentTypeID=1Wed, 19 Jun 2019 07:32:39 GMT137ad170-7792-4731-bb38-c0d22fbe4515:830301b9-9508-4d45-8834-6ad62292b58fawneil[quote userid="80723" url="~/f/nordic-q-a/48747/seggar-embedded-studio-can-recognize-the-nrf52840-development-board-but-not-the-external-device-debugging-target"]Seggar <i>(sic)</i> Embedded Studio just kept downloading the code to the development kit[/quote] <p>* Segger</p> <p>Whether the on-board nRF52840 or the external target is accessed is controlled by the DK <em><strong>hardware</strong> </em>- not SES:</p> <p style="padding-left:30px;"><em>&quot;When the external board is powered, the interface MCU will detect the supply voltage of the board and program/debug the target chip on the external board instead of the onboard nRF52840&nbsp;<a title="A microchip that integrates all the necessary electronic circuits and components of a computer or other electronic systems on a single integrated circuit." href="https://infocenter.nordicsemi.com/topic/ug_nrf52840_dk/dita_common/glossary/glossary.html#soc"><dfn class="term abbreviated-form">SoC</dfn></a>&quot;</em></p> <p style="padding-left:30px;"><a href="https://infocenter.nordicsemi.com/topic/ug_nrf52840_dk/UG/nrf52840_DK/hw_debug_out.html?cp=3_0_4_7_9">https://infocenter.nordicsemi.com/topic/ug_nrf52840_dk/UG/nrf52840_DK/hw_debug_out.html?cp=3_0_4_7_9</a></p> <p>So there must be a problem with your connection to the external target - in particular, check the EXT_VTG line.</p> <p></p><div style="clear:both;"></div>