https://devzone.nordicsemi.com/f/nordic-q-a/35677/sharing-32-768khz-xtalIf we are using an external RTC(for example, PCF85063) with a 32.768kHz XTAL, can we rely on the internal RC oscillator on nRF52840 for the power savings in Deep Sleep mode? If not, can we share the same 32.768kHz XTAL between RTC and nRF52840?en-USTelligent Community 13Mon, 25 Jun 2018 12:07:41 GMThttps://devzone.nordicsemi.com/thread/137429?ContentTypeID=1Mon, 25 Jun 2018 12:07:41 GMT137ad170-7792-4731-bb38-c0d22fbe4515:35fc2cf4-5caf-44f3-a317-c4c57f9a27d1ketiljo<p>You can feed the 32 kHz signal from the RTX into the nRF52. See the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52840.ps/clock.html?cp=2_0_0_4_3_2_7#register.LFCLKSRC">LFCKSRC</a> register. Also see <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52840.ps/clock.html?cp=2_0_0_4_3_1#concept_xkj_np1_2r">table 1 here</a>.&nbsp;</p> <p>Using the RC oscillator is also possible, but for long intervals, the crystal will be much more accurate.&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p><div style="clear:both;"></div>