https://devzone.nordicsemi.com/f/nordic-q-a/39166/using-nrf52832-with-sdk-v11-0-0-and-sd132---how-to-determine-if-external-crystal-is-selectedHello, We are currently using RTC1 and RTC2 to keep track of various times. RTC2 is our dedicated clock to keep track of time. I want to ensure that indeed, our application is using our external 32,768 Hz oscillator (referred to as &#39;LFXO&#39; in the manualen-USTelligent Community 13Fri, 05 Oct 2018 11:57:11 GMThttps://devzone.nordicsemi.com/thread/151824?ContentTypeID=1Fri, 05 Oct 2018 11:57:11 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c0b1d69c-4df1-4dc7-a426-1e6bd95ee102MartinBL<p>Yes and yes.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/151720?ContentTypeID=1Thu, 04 Oct 2018 17:01:41 GMT137ad170-7792-4731-bb38-c0d22fbe4515:24795648-e453-4198-99d3-7cac843ce576Sami<p>Thank you MartinBL. Yes, and:</p> <p>// does this select the external crystal?&nbsp;</p> <p class="p1">NRF_CLOCK-&gt;<span class="s1">LFCLKSRC</span><span class="Apple-converted-space">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </span>= (CLOCK_LFCLKSRC_SRC_Xtal &lt;&lt; CLOCK_LFCLKSRC_SRC_Pos);</p> <p class="p1"></p> <p class="p1">// I&#39;m assuming this starts the external crystal:</p> <p class="p1">NRF_CLOCK-&gt;<span class="s1">TASKS_LFCLKSTART</span><span class="Apple-converted-space">&nbsp; &nbsp; </span>= 1;</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/151581?ContentTypeID=1Thu, 04 Oct 2018 07:33:44 GMT137ad170-7792-4731-bb38-c0d22fbe4515:24cbd31d-d5cb-45b2-a91e-0e0cc3ccad34MartinBL<p>Hi,</p> <p>You can use the register <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/clock.html?cp=2_1_0_18_2_5#register.LFCLKSTAT">NRF_CLOCK-&gt;LFCLKSTAT</a> for this. It gives you the clock source and whether or not it is running.</p><div style="clear:both;"></div>