21.9.13 Specifying Clock-to-Clock Uncertainty Constraint

Use the clock-to-clock uncertainty constraint to model tracking jitter between two clocks in your design.

To specify the clock-to-clock uncertainty constraint:

  1. Add the constraint in the editable constraints grid or open the Set Clock-to-Clock Uncertainty Constraint dialog box using one of the following methods:
    • From the SmartTime Actions menu, choose Constraints > Clock-to-Clock Uncertainty Constraint.
    • Click the þÿ icon.
    • Right-click Clock-to-Clock Uncertainty Constraint in the Constraint Browser.
    • Double-click any field in the Clock-to-Clock Uncertainty Constraint grid.
  2. Specify the from and to clocks and specify the uncertainty in ns.
  3. Enter any comments to be attached to the constraint.
  4. Click OK. The new constraint appears in the constraints list.
Note: When you choose Commit from the File menu, SmartTime saves the newly-created constraint in the database.