https://devzone.nordicsemi.com/f/nordic-q-a/4667/nrf51822-clock-interface-to-mcp25625Hi All, I am designing a circuit with nrf51822 and mcp25625 (microchip spi can interface). mcp25625 has an internal 16mHz xtal clock circuit and a digital clock out, I am planning to use this clock out to feed the nrf chip through xc1 input. Whenen-USTelligent Community 13Tue, 02 Dec 2014 05:42:55 GMThttps://devzone.nordicsemi.com/thread/16561?ContentTypeID=1Tue, 02 Dec 2014 05:42:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6a7c961b-dfa0-429b-b811-c2bffe6f115fhakki goceoglu<p>Hi John, Thanks for the answer, I had gone through all the docs but obviously I missed some important information. I will go on with my tests as you have suggested. Regards</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/16560?ContentTypeID=1Mon, 01 Dec 2014 21:36:29 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7af15835-1a64-4d33-bc72-fa195ad08296John<p>Hi hakki,</p> <p>I&#39;ll do my best to get you pointed in the right direction on this. First, let me suggest that you read section 13 in the nRF51 (version 3.0) reference manaual. It has a lot of detail on the HF clock operation. I had to read it several times before a lot of it sunk in. I would also suggest that you read section 3.6 on clock management in the nRF51822 (version 3.1) product specification. This will fill in a lot of what you need to know about the clocking system.</p> <p>The nRF51822 does have an internal 16MHz RC oscillator that it can start up on. That should be enough to allow you to configure the mcp25625 device to output a 16MHx clock. I would advise that you ensure it can meet the accuracy specifications needed to run the radio if you are planning to do so. I believe it is +/-40ppm.</p> <p>There is also some very good information about clocking in the answer to this question: <a href="https://devzone.nordicsemi.com/question/18096/what-is-the-high-frequency-clock-model-for-nrf51/?answer=18097#post-id-18097">clocking answer</a></p><div style="clear:both;"></div>