Timing constraints are used to ensure that a design meets the required timing performance.
Constraints can be entered using a ProASIC constraints file (.gcf) or using an SDF path constraints file. These forward SDF files are generated by synthesis tools. The two formats cannot be combined in one file. However, SDF files and ProASIC (.gcf) constraint files can be used for the same design. Place-and-Route considers timing constraints and attempts to meet them. After routing, Designer displays a message that indicates if your timing constraints were met.
ProASICPLUS supports only SDC timing constraint files. (GCF timing constraints are no longer supported.) If you open a ProASICPLUS design with GCF timing constraints in Designer it converts your GCF timing constraints to SDC constraints automatically. After your GCF timing constraints are converted Designer creates an SDC file with your new constraint information. You do NOT have to re-import your SDC file to get your constraints, it happens internally. See the related topics below for more information on GCF to SDC timing constraint conversion.
Place-and-route considers your timing constraints and attempts to meet them. After routing, Designer displays a message that indicates if your timing constraints were met.