https://devzone.nordicsemi.com/f/nordic-q-a/55204/uart-exampleHi i want to send a string using uart over bluetooth. For a try i compile ble_app_uart and flash it to my dk but i can not see the message on the terminal neither in Putty nor in JlinkRTTviewer. I can&#39;t even connect my board to the putty, is anyoneen-USTelligent Community 13Fri, 06 Dec 2019 11:44:07 GMThttps://devzone.nordicsemi.com/thread/224144?ContentTypeID=1Fri, 06 Dec 2019 11:44:07 GMT137ad170-7792-4731-bb38-c0d22fbe4515:727905ae-5db5-49cf-a27c-e945c68023f6Mttrinh<p>Hi,</p> <p>You are probably missing an external crystal. Most of our examples from the SDK uses the&nbsp;<span>external LFCLK by default</span>. If you don&#39;t have one, this <a href="https://devzone.nordicsemi.com/f/nordic-q-a/48136/using-soft-device-on-custom-board-with-nrf52840" rel="noopener noreferrer" target="_blank">post</a> might help you.</p> <p>Hope this helps.</p><div style="clear:both;"></div>