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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 Contributor --- Quote Start --- P.P.S.: Or do you have a M9K-block connected to this clock? That has a fmax of 238MHz with -8 speedgrade. --- Quote End --- Yes, Quartus knows about the frequency, i constrained the PLL input and the 400 is inclk x 10. Duty cycle is 50%. There is a small altera fifo generated here (built around an M9K), i guess you're right. I should generate it in logic (size only 4x16). Hope it works!
