https://devzone.nordicsemi.com/f/nordic-q-a/11047/need-extra-settings-when-using-softdevice-32mhz-and-nrf51822Hi, I&#39;m planning to made a custom PCB using nRF51822-QFAA or QFAC revision 3. My developing environments are J-Link, IAR EWARM 7.1, SoftDevice 7.1, and SDK 7.2. I kept used 16MHz external oscillator at my custom PCB. I&#39;m planning to change theen-USTelligent Community 13Mon, 18 Jan 2016 21:51:10 GMThttps://devzone.nordicsemi.com/thread/41284?ContentTypeID=1Mon, 18 Jan 2016 21:51:10 GMT137ad170-7792-4731-bb38-c0d22fbe4515:95e6e79f-dee9-4c53-b36f-3319cf5fc42bMartijn<p>You need to tell the CLOCK peripheral what crystal you are using via the XTALFREQ register. You can override default value by setting the UICR-&gt;XTALFREQ register to what you need.</p><div style="clear:both;"></div>