Description
It is not possible to edit the parameters of fPLLs using the Resource Property Editor or Chip Planner in the Quartus® II software when designing with Stratix® V, Arria® V, or Cyclone® V devices.
Resolution
Utilize the PLL Reconfiguration feature to dynamically update the fPLL parameters.
For further details, refer to AN661: Implementing Fractional PLL Reconfiguration with Altera PLL and Altera PLL Reconfig Megafunctions (PDF)