https://devzone.nordicsemi.com/f/nordic-q-a/118836/nrf21540-custom-board-dtm-direct-test-mode-failedHello, I am currently working on a project using a custom board with nRF52840 + nRF21540 . I am trying to measure wireless performance using Direct Test Mode (DTM) , but the test fails in the Direct Test Mode desktop application , preventing the testen-USTelligent Community 13Tue, 11 Feb 2025 14:13:23 GMThttps://devzone.nordicsemi.com/thread/522460?ContentTypeID=1Tue, 11 Feb 2025 14:13:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d8b5b1a5-5429-4695-bc27-f07da31a4192Asbj&#248;rn<div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;">Hello Kevin,</div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;"></div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;">I only have the nRF21540-DK available here, but I was able to build and run the DTM service in nrf connect for desktop with it.&nbsp;</div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;"></div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;">A couple of things to check, you have a custom board, does it have an external 32k crystal or have you configured the DTM to use the RCOSC?</div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;">Have you changed the pin functionality of any of the GPIOs related to the UART interface or have you mapped up your pin selection to the nRF connect expectation? The command fail is usually related to either of those two changes.</div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;">Do you have a USB to UART translator on your board?</div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;"></div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;"></div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;">Best regards</div> <div style="background-color:rgba(255, 255, 255, 1);border:0;color:rgba(0, 0, 0, 1);direction:ltr;font-size:11pt;font-style:normal;font-weight:400;letter-spacing:normal;line-height:inherit;margin:0;padding:0;text-align:left;text-indent:0;text-transform:none;vertical-align:baseline;white-space:normal;">Asbjørn</div><div style="clear:both;"></div>