Each step of the wizard can recommend several constraints. Depending on the constraint, you must take one of the following actions:
- Uncheck the constraints you do not want to create, using one of the
Tip: Alternatively, you can right-click the constraint, and select Do Not Create Constraint, as shown in the following figure.Figure 1. Skipping Recommended Constraints Using the Context Menu
- Remove each constraint from the list, one at a time, by unchecking each line.
- Remove all constraints by unchecking the upper left check box of the table.
In the following figure,
ddr_clk_inare unchecked and will be skipped.Figure 2. Creating and Skipping Recommended Constraints
- Enter the missing values by clicking on the cells that show
undefined (for example, the Frequency or Period value for
clk3in the previous figure).
You can edit several constraints at the same time by selecting the corresponding rows and clicking the Edit Selected Rows button, as shown in the following figure.Figure 3. Editing Several Recommended Constraints
Next, fill out any required fields, such as Frequency and Period as shown in the following figure:Figure 4. Entering Parameters for Several Recommended Constraints
Editing multiple constraints at a time is particularly helpful for input and output delay constraints.
- Simply review the constraints if no action is required.
When all the checked recommended constraints have been reviewed and completed, click Next to proceed to the next page. Any entries that you missed prevent the wizard from moving to the next step.
You can use the Back button to revisit a page. If you edit any constraint on a previous page and click Next, the wizard re-analyzes the design and recommends new constraints accordingly. In most cases, the previously recommended constraints not affected by the change are reinstated. If you only view a previous page without modifying any of its recommended constraints, the wizard does not re-run any analysis, which usually saves runtime.