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Altera_Forum
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15 years ago

pll reconfiguration and CP/LF parameters

Documentation describing the pll scan chain is clear enough for the settings of the m,n,cx counters. However, it is not clear to me how the charge-pump and loop-filter parameters should be calculated...
Altera_Forum's avatar
Altera_Forum
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15 years ago

Hi Johannes,

I can imagine that the tables may be complicated if you have to support all possible configuration scenarios of the PLLs (multi-freq, dephasing, chaining, etc...), but I don't believe this is true in the case of a single frequency generation. All examples read so far in the doc do anyways stick to such simple scenarios when it comes to use the reconfiguration component. A small effort from Altera to extract the meaningful part of the table (or write down the needed formula) would allow the user to use the reconfiguration component as a standalone component. This is not the case today, the megawizard is still needed for 2 undescribed parameters. I'll have again to hardcode all (fixed) values and limit the freedom to generate any wished frequency.

Thanks all for your replies!

P9