Project Flows - Project Flows - 2026.1 English - UG903

Add Xilinx design constraints (XDC) files to a constraints set when creating a project or later through the Vivado IDE menus.

The following figure shows two constraint sets in a project. The first constraint set includes two XDC files. The second constraint set uses one XDC file containing all the constraints.

Figure 1. Single or Multi XDC

You can also add Tcl scripts to your constraints set as unmanaged constraints or unmanaged Tcl scripts. The AMD Vivado™ Design Suite does not write modified constraints back into an unmanaged Tcl script. Tcl scripts and XDC files load in the order shown in Vivado IDE when in the same PROCESSING_ORDER group, or as reported by report_compile_order -constraints.

You can include an XDC file or Tcl script in multiple constraint sets when necessary.

Follow these steps to add constraints to a project:

1. Open or create a project in the Vivado IDE.
2. Add XDC files to a constraints set during project creation or later through the Vivado IDE menus.
3. If needed, add unmanaged Tcl scripts to a constraints set.
4. Verify the order in which the constraints load by reviewing the constraints set in the Vivado IDE or by running report_compile_order -constraints.

For more information about constraint files and sets, refer to Working with Constraints in the Vivado Design Suite User Guide: System-Level Design Entry (UG895).