Setting Constraints for Unrelated Clocks

The first step is to analyze your design to determine which clocks are related and which are not. You then use one of the following constraints:

• set_clock_groups—Use when you want to specify bidirectional constraints between clocks. Generally, this is the simplest method, and the fastest for the Efinity® timer to analyze. (See set_clock_groups Constraint.)
• set_false_path—Use when you want to be specific about which clocks connect with which end points. This constraint is one-directional, so you need to specify two constraints, one for each direction. (See set_false_path Constraint.) Typically, you use these constraints when you want to indicate timing exceptions for a subset of timing end points in one of the clock domains.