Forum Discussion
Altera_Forum
Honored Contributor
Honored ContributorCyclone V Fractional PLLs don't output expected clock frequency
I'm using Quartus 17.0.2. I have trying to generate a 148.5MHz clock with a 50MHz input reference clock. When I put the PLL in fractional mode and enter 148.5M as my target frequency the megawizard s...
Altera_ForumHonored Contributor
Honored Contributor --- Quote Start --- There are two options to generate an output clock frequency. --- Quote End --- Yes, the physical parameter options should be used if you are not satisfied with the automatically generated parameters. The point is that previous Quartus versions, e.g. Quartus 13.1 which I use for existing Cyclone V projects, seem to generate useful fractional parameters automatically. But the reported parameters in your post# 1 suggest, that Quartus 17 generated an integer PLL although a fractional PLL was intended.
