Forum Discussion
Altera_Forum
Honored Contributor
14 years agoHello.
I am beginning to study Stratix-IV and I have the same question. I am trying to use ALTGX on Stratix-IV. So I make a project with ALTGX and trying to compile it. There are two ways for me now: 1) I make constraints for input frequencies and put "derive_pll_clocks" in .sdc file. Quartus V11 successfully compile my project without warnings or messages about unconstrained paths. 2) When I create/update .sdc file in TimeQuest, it adds multiple constraints in this .sdc file that concerns ALTGX. If I compile my project with such .sdc file, about 30 warnings appear. Also unconstrained pathes appeared. It seems to me that constraints that TimeQuest generate for ALTGX, do not correspond to my own implementation of ALTGX... So there is a question, how to make proper constraints for ALTGX? Is the way 1) good for using, or I should make TimeQuest' constraints to work good? Are there some Application Note for ALTGX constraining? Thank you in advance.