Hi, all
quartus ip : quartus 191
IP : fpll
operation mode : fraction mode
For change the frequency of fpll:
I modify c0/m/n/k, after configure these register , then use register to reset and re-calibrate fpll.
I found that:(during simulation)
1) if there's no m change, though k value is changed, the fpll could not synthesis the new frequency;
workaround : I must change m to another value then change it back, then update k value; the fpll could synthesis the new frequency; I don't know why. it's so strange.
2) Though there's workaround solution, but I found that sometimes, previous and current k value has large difference(for example ,previous value is 32'h98dbc000 , current value is 32'h5b110000), but the fpll could not provide correct frequency. How could I resolve this issue? Or which way will I need to try?
Best Regards,
Lambert
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I made sure I have written all register correctly through reading the related register after write. And I found that 1st k value, 2ed k value has same frequency; 3rd value, 4th value has another same frequency; 1st and 2ed k value is diff; 3rd value and 4th value is diff. Update frequency is 861us.
Hi,
Now I only have tried the quartus 191 and only did the simulation, I will check this IP using quaruts 24.
Hi,
Just because I could not send our project to you(I have limited authority). I could only present my implementation step.
1. Configure fpll to one default frequency;
2. During simulation, use fixed M count, and continue to adjust K count. (gap about 800 us).
Use same N and C0 count;
For the dynamic configuration:
1. configure C0;
2. configure M
3, configure N;
4. configure K
5. power down to do reset and re-calibration
Or maybe could you help provide one example, and I could try it at my side, thanks
Best Regards
Hi,
I am so sorry that I have limited authority that I could not transfer our design to you. But for the fpll design, I could provide the related configuration :
And I think this information could help to generate the related IP. About dynamic logic, maybe you need to re-design.
