Forum Discussion
Altera_Forum
Honored Contributor
Honored Contributorcyclone 3 restricted fmax
Hi, at some point during my work I needed to use a higher frequency clock in Cyclone 3 (EP3C16) speedgrade -8 and thought of a 400 MHz clock. In the Cyclone 3 Handbook volume 2 table 1-19 it i...
Altera_ForumHonored Contributor
Honored ContributorI think, I have seen similar things. My explanation for it was that some global clock networks have a lower fmax then others, but this is just a guess. Have you constrained your clock, so that the fitter knows that you want to achieve 400MHz?
Thomas P.S.: I suppose you have not specified a duty-cycle for your clock different to 50%?
