In the Vivado® IDE, you can set bus skew constraints in multiple ways:
- Through the Timing Constraints Editor. Select .
From the Timing Constraints Editor, you can add, remove, or modify bus skew constraints.
Note: Locked IP bus skew constraints cannot be edited. - Through the Report CDC GUI. Select .
Inside the CDC Details tables, you must select one or more rows to include at least two or more startpoints and two or more endpoints. When you right-click and select Set Bus Skew, there are two options:
- Startpoint to Endpoint
- Set a bus skew constraint between the startpoints and endpoints included in the selected row(s).
- Source Clock to Destination Clock
- Set bus skew constraints between the clock domains of the startpoints and
endpoints.Note: It is typically not recommended to set a bus skew constraints between clock domains, because it will apply to more paths than needed. This will result in longer implementation runtime and impossible timing closure.
Figure 1. Setting Bus Skew within Report CDC
Note:
Vivado does not verify the
validity of setting a bus skew constraint on the selected objects. You must ensure that
a bus skew constraint makes sense with the selected objects.
In the Set Bus Skew dialog box, you can set the bus skew value, the startpoints, and endpoints, as shown in the following figure.
Figure 2. Set Bus Skew Dialog Box
