Creating Groups with TIMEGRP
Another way to constrain this design is by creating smaller groups of endpoints:
The TIMEGRP constraint is used to create new groups from other groups.
FFS, LATCHES, RAMS, and PADS are predefined groups
Example: ALL_FFS group contains all Flip-Flops whose instance name begins with SLOWFF or FASTFF:
INST SLOWFF* TNM = SLO;
INST FASTFF* TNM = FST;
TIMEGRP ALL_FFS = FFS (FST* : SLO*) ;