All Constraints - 2021.2 English

Vivado Design Suite User Guide: Using Constraints (UG903)
Document ID
UG903
Release Date
2021-11-17
Version
2021.2 English

The bottom of the window displays the complete list of constraints loaded in memory, in the same sequence as they were applied. The constraints are grouped in accordance with the XDC file or the Tcl script from which they originated. When an XDC file is scoped to a particular hierarchical cell, the cell name is displayed next to the file name.

Figure 1. Timing Constraints All Constraints List (Example One)

You can expand and collapse the constraints for each associated source file, or completely by clicking the two corresponding buttons on the left side of the panel.

Figure 2. Timing Constraints All Constraints List (Example Two)

Tip: The collapsed view provides a compact overview of which constraints file are loaded in memory, and where the scoping mechanism is used. The same information is available through the report_compile_order -constraints command.

De-select the Group by Source icon to switch the view to a table in which the source constraint file and the scoped cell information appears in the two right columns.

Figure 3. Timing Constraints All Constraints List (Example Three)

  • To delete a constraint, select it and click X.
  • To edit a constraint that is not read-only, use the spreadsheet view. After your changes have been registered by the tool, you must click Apply to refresh the constraints in memory.
  • To add new constraints, use the dialog boxes as previously described, or type the constraints in the Tcl console. The new constraint appears at the end of the list in a group named <unsaved_constraints>.
Figure 4. Timing Constraints All Constraints List (Example Four)

When saving the constraints, the new constraints are saved at the end of the XDC file marked as target. If there is no target XDC file in the constraint set associated with the design in memory, or if there is only a Tcl script in the constraint set, you are prompted to specify where to save the constraints.

Regularly save your constraints. Click Save, or select File > Constraints > Save.

Important: New and modified constraints cannot be saved back to a Tcl script.
CAUTION:
Do not enter new constraints in the Tcl Console if any constraints in the Timing Constraints window have not yet been applied. The final constraints order in the editor can become different from the constraints order in memory. In order to avoid any confusion, you must re-apply all constraints each time you edit an existing constraint.