Re: Quartus produces wrong parameters for Stratix PLL

snipped-for-privacy@yahoo.com (Michael S) wrote in message



In Stratix devices there are two types of PLLs - Enhanced PLLs and
Fast PLLs.  The Megawizard performs a feasibility check to make sure
the resulting parameters the compiler will compute (including the VCO
frequency) will be valid for at least one of these PLL types.  For
Quartus II 3.0, the Megawizard is aware of the restriction that forces
the use of Enhanced PLLs when using reconfiguration, and as a result
will make sure all parameters can be implemented in an Enhanced PLL
earlier on in the flow.

But even in Quartus II 2.2, the compiler will give an error if the PLL
cannot be implemented in either of the PLL types, including if no set
of internal parameters could achieve the requested PLL settings and a
legal VCO for the speed grade selected.  If a legal set of internal
parameters did exist that could achieve the requested PLL settings,
then the compiler will implement those parameters.

Quartus II 3.0 was released to production/manufacturing on June 27th
so you should be seeing it real soon.

- Subroto Datta
Altera Corp.