https://devzone.nordicsemi.com/f/nordic-q-a/81077/bluetooth-module-bt840f-based-upon-nrf52840-doesn-t-seem-to-advertiseI am using Fanstel&#39;s BT840F BLE module which is based upon nRF52840 for my application. I am using PCA10056 DK to program it. I tried to program the BLE module on the DK with ble_app_beacon example and it successfully shows itself in the nRF Connect Androiden-USTelligent Community 13Wed, 27 Oct 2021 07:02:08 GMThttps://devzone.nordicsemi.com/thread/336097?ContentTypeID=1Wed, 27 Oct 2021 07:02:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:17216510-bcd1-459b-a954-2a6e7d4b8971Simonr<p>Hi</p> [quote user=""] I tried to program the BLE module on the DK with ble_app_beacon example and it successfully shows itself in the nRF Connect Android app as &quot;nRF Beacon&quot;.[/quote] <p>I assume this was the DK itself you programmed with the BLE app beacon? Please note that the nRF52840 should only be powered by 1.7-3.6V. I assume you power it with high voltage mode operating voltage, where the typical voltage is 3.7V.</p> <p>The most common issue with third party modules is that they don&#39;t have the external LF crystal which all our SDK examples use by default. Please try changing the following configs in the projects sdk_config.h header file to these values, as that&nbsp;is likely to fix your issue.&nbsp;</p> <p><pre class="ui-code" data-mode="c_cpp">//========================================================== // &lt;o&gt; NRF_SDH_CLOCK_LF_SRC - SoftDevice clock source. // &lt;0=&gt; NRF_CLOCK_LF_SRC_RC // &lt;1=&gt; NRF_CLOCK_LF_SRC_XTAL // &lt;2=&gt; NRF_CLOCK_LF_SRC_SYNTH #ifndef NRF_SDH_CLOCK_LF_SRC #define NRF_SDH_CLOCK_LF_SRC 0 #endif // &lt;o&gt; NRF_SDH_CLOCK_LF_RC_CTIV - SoftDevice calibration timer interval. #ifndef NRF_SDH_CLOCK_LF_RC_CTIV #define NRF_SDH_CLOCK_LF_RC_CTIV 16 #endif // &lt;o&gt; NRF_SDH_CLOCK_LF_RC_TEMP_CTIV - SoftDevice calibration timer interval under constant temperature. // &lt;i&gt; How often (in number of calibration intervals) the RC oscillator shall be calibrated // &lt;i&gt; if the temperature has not changed. #ifndef NRF_SDH_CLOCK_LF_RC_TEMP_CTIV #define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2 #endif // &lt;o&gt; NRF_SDH_CLOCK_LF_ACCURACY - External clock accuracy used in the LL to compute timing. // &lt;0=&gt; NRF_CLOCK_LF_ACCURACY_250_PPM // &lt;1=&gt; NRF_CLOCK_LF_ACCURACY_500_PPM // &lt;2=&gt; NRF_CLOCK_LF_ACCURACY_150_PPM // &lt;3=&gt; NRF_CLOCK_LF_ACCURACY_100_PPM // &lt;4=&gt; NRF_CLOCK_LF_ACCURACY_75_PPM // &lt;5=&gt; NRF_CLOCK_LF_ACCURACY_50_PPM // &lt;6=&gt; NRF_CLOCK_LF_ACCURACY_30_PPM // &lt;7=&gt; NRF_CLOCK_LF_ACCURACY_20_PPM // &lt;8=&gt; NRF_CLOCK_LF_ACCURACY_10_PPM // &lt;9=&gt; NRF_CLOCK_LF_ACCURACY_5_PPM // &lt;10=&gt; NRF_CLOCK_LF_ACCURACY_2_PPM // &lt;11=&gt; NRF_CLOCK_LF_ACCURACY_1_PPM #ifndef NRF_SDH_CLOCK_LF_ACCURACY #define NRF_SDH_CLOCK_LF_ACCURACY 1 #endif</pre></p> <p>Best regards,</p> <p>Simon</p><div style="clear:both;"></div>