https://devzone.nordicsemi.com/f/nordic-q-a/12221/stuck-in-this-linehi im using one of SDK Example and it stuck in this line of code // Initialize SoftDevice. SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_75_PPM, NULL); in this line my program stuck i use nrf51422 and keil s130 BLE and when in debugen-USTelligent Community 13Tue, 01 Mar 2016 08:21:29 GMThttps://devzone.nordicsemi.com/thread/46233?ContentTypeID=1Tue, 01 Mar 2016 08:21:29 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3a03545f-e02e-4cfa-9b20-c5618a476683MartinBL<p>I guess this question is related to <a href="https://devzone.nordicsemi.com/question/69707/what-freq-for-softdevice-should-i-use/">your question yesterday</a>.</p> <p>The reason why SOFTDEVICE_HANDLER_INIT() hangs is almost always due to wrong clock source configuration. Make sure you follow @Kristin&#39;s tips in the other thread. If you use an external oscillator you should also make sure that it is mounted properly (proper soldering and correct positioning). <a href="https://devzone.nordicsemi.com/question/953/what-low-frequency-clock-sources-can-i-use/">Here is a great post</a> on low frequency clock sources.</p> <p>The reason it hangs can also be that you use incompatible Softdevice and SDK. Make sure your comply with the <a href="http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf51%2Fdita%2Fnrf51%2Fpdflinks%2Fnrf51_comp_matrix.html">Compatibility Matrix</a>. If you don&#39;t you can&#39;t expect it to work.</p><div style="clear:both;"></div>