https://devzone.nordicsemi.com/f/nordic-q-a/14547/nrf51422-on-custom-boardHi we have a custom board, where the clock does not start (verified by osciloscope). We do not use an external clock, so from our understanding the command to init the S130 soft device should be changed from SOFTDEVICE_HANDLER_INIT(&amp;clock_lf_cfgen-USTelligent Community 13Fri, 17 Jun 2016 09:35:02 GMThttps://devzone.nordicsemi.com/thread/55554?ContentTypeID=1Fri, 17 Jun 2016 09:35:02 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c7f8f385-4862-4e42-8d32-ac8a73c29315Ole Bauck<p>You have to change clock_lf_cfg to for example:</p> <pre><code>//internal clock configuration nrf_clock_lf_cfg_t rc_clock_lf_cfg = {.source = NRF_CLOCK_LF_SRC_RC, \ .rc_ctiv = 1, \ .rc_temp_ctiv = 1}; //synth clock configuration nrf_clock_lf_cfg_t synth_clock_lf_cfg = {.source = NRF_CLOCK_LF_SRC_SYNTH, \ .rc_ctiv = 0, \ .rc_temp_ctiv = 0, \ .xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_20_PPM}; </code></pre> <p>See <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s130.api.v2.0.0/structnrf__clock__lf__cfg__t.html">here</a> for a description of the data fields. We do not recommend using synthesized clock as this draws considerably more power than using RC clock.</p><div style="clear:both;"></div>