Before generating the CDC report, you must ensure that the design has been properly constrained and there are no missing clock definitions. Report CDC only analyzes and reports paths where both source and destination clocks have been defined. Report CDC performs structural analysis:
- On all paths between asynchronous clocks.
- Only on paths between synchronous clocks that have the following timing exceptions:
- Clock groups
- False Path
- Max Delay Datapath Only
Synchronous clock paths with no such timing exception are assumed to be safely timed and are not analyzed by the CDC engine. The Report CDC operates without taking into consideration any net or cell delays.