====== Add a Master XDC File to a Vivado Project ======
~~TechArticle~~
If your project doesn't contain the master Xilinx Design Constraint (XDC) file for your board, the dropdown below details how to add it. This file contains the constraints that your board places on designs using it - specific interfaces wired up to specific pins, clock frequencies, and FPGA bank voltages, for some examples. Click the dropdown below for a walkthrough of how to add this file to your project.

--> Add a Master XDC File to a Vivado Project #
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Download and extract {{https://github.com/Digilent/digilent-xdc/archive/master.zip|digilent-xdc-master.zip}}. This file includes all of the latest template XDC files released for Digilent's boards, which are available on Github in the [[https://github.com/Digilent/digilent-xdc|digilent-xdc]] repository.
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{{learn:programmable-logic:tutorials:2020.1:add-gpio-to-block-design:extracted-xdc-folder.png?600|}}
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Returning to Vivado, click the **Add Sources** button in the //Project Manager// section of the //Flow Navigator// pane. This will launch a dialog that you can use to add a variety of types of source files to the project (or create new ones).
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{{learn:programmable-logic:tutorials:2020.1:add-gpio-to-block-design:add-sources.png?600|}}
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On the first screen, select //Add or create constraints//. Click **Next** to continue.
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{{learn:programmable-logic:tutorials:2020.1:add-gpio-to-block-design:add-constraints.png?600|}}
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In the next screen, make sure that the constraint set specified (the one that the master XDC will be added to) is set to //constrs_1//, and that it is the //active// set. Click the **Add Files** button.
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{{learn:programmable-logic:tutorials:2020.1:add-gpio-to-block-design:add-files.png?600|}}
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In the dialog that pops up, navigate to the folder that the //digilent-xdc-master.zip// file was extracted into. Highlight the XDC file for your board, then click **OK** to continue.
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{{learn:programmable-logic:tutorials:2020.1:add-gpio-to-block-design:find-xdc.png?600|}}
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Back in the //Add Sources// dialog, make sure that your chosen constraint file appears in the table. Also, make sure that the //Copy constraint files into project// box is checked. If this box is unchecked, the file will be linked by your project, and any modifications made within the project will affect the version you downloaded. Since you may need to use this file again in other projects, copying the constraint file is recommended, so that you can always work from a fresh copy.

Click **Finish** to add the constraint file to your project.
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{{learn:programmable-logic:tutorials:2020.1:add-gpio-to-block-design:import-constraint-file.png?600|}}
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Once added, the XDC file will appear in the //Sources// tab (in the same pane as the //Board// tab). Double click it to open the file.
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{{learn:programmable-logic:tutorials:2020.1:add-gpio-to-block-design:open-constraint.png?600|}}
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