Leonardo, I have attached Silicon Devices Application Note AN334v4, which contains the relevant code, written in C on pages 19 and 20. According to the SI570 FAQ: 4. Why do we need to calculate fXTAL when reconfiguring the output clock for large changes in output frequency? Each Si57x device has a unique crystal. The crystal frequency is nominally 114.285MHz but may be offset from this value by +/-2000ppm. We calculate fXTAL in order to determine the exact crystal frequency and then use this information to adjust the DSPLL feedback divider ratio and output divider ratios. (Crystal manufacturers cannot tune the crystals and achieve the same initial accuracy as is possible with the DSPLL approach.) Determination of fXTAL occurs when the SI570 is first powered up. I hope this helps answer your question. 73, Mac AE5PH On 02/05/2014 01:54 PM, Leonardo Ramirez wrote:
Hi. How i can know the frequencyof the crystal mySi570? Thanks. EA7KB
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AN334v4.pdf
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