Hi, I'm interested in trying out the spread spectrum feature of the MPC5748G PLL.
Wondering if there are reference register values available for STEPSIZE, STEPNO, etc. I could use to test quickly while I work through the equations.
Thanks,
Steve
Hi,
I have created example SW for you.
My STEP is 250 and modulation frequency is 20kHz.
I have verified it with spectral analyzer. You can use it as a reference.
https://community.nxp.com/docs/DOC-334867
Peter
That is awesome Peter, Thanks!
We do not have reference example for frequency modulation.
You have to calculate STEPSIZE and STEPNO.
From my past experience I recommend you after calculation to use spectral analyzer for manual fine tuning.
Hi Peter, does STEPSIZE need to be non-zero?
If so, then I don't see how the calc can possibly work because with a 40MHz crystal and modulation freq=10kHz --> STEPNO=2000. N would have to be >2000 for STEPSIZE to round to anything other than 0.
What am I missing?
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