Add Pin Constraint

The following content has been imported from Legacy Help systems and is in the process of being checked for accuracy.

Parent process: EditConstraints:AddConstraint

Applied parameters: Type=AddPin

Summary

This command is used to add or modify a constraint group targeting a specific pin, within the active constraint file.

Details

First, ensure that the constraint file in which you wish to add or modify a Pin constraint group, is open as the active view in the main design window.

After launching the command, the Add/Modify Pin Constraint dialog will appear.

Adding a new Pin constraint

If you wish to add a new Pin constraint group to the file, simply type the name of the target pin into the Target field.

There is only one entry available for selection in the Constraint Kind drop-down field for this particular constraint target - FPGA_RESERVE_PIN. This constraint is used to ensure that the Vendor Place & Route tools do not assign the physical pin of the device (specified in the Target field) to any of the top-level ports in the FPGA design. The corresponding Constraint Value can be either True or False.

After clicking OK a constraint group statement will be added to the constraint file. The statement will appear in the following form:

Record=Constraint | TargetKind=Pin | TargetId=[Target field] | FPGA_RESERVE_PIN=[Constraint Value field]

For example, consider the case where you do not want the Place & Route tools to assign pin 188 of the physical FPGA device to any of your design's ports. In the Add/Modify Pin Constraint dialog, you would enter P188 into the Target field, select FPGA_RESERVE_PIN as the Constraint Kind and then choose True in the Constraint Value field. The Pin constraint group statement added to the file would be:

Record=Constraint | TargetKind=Pin | TargetId=P188 | FPGA_RESERVE_PIN=True

Modifying an existing Pin constraint

If you wish to modify an existing Pin constraint group within the file, simply enter the name of the pin to be modified in the Target field and change the value for the FPGA_RESERVE_PIN constraint as required (True or False).

After clicking OK, the corresponding constraint group statement will be updated with the modified constraint information.

Notes

A constraint group is a single statement in a constraint file, targeting one or more objects and containing one or more specific constraints.

When adding a Pin constraint group for the first time, the entry will appear below any other constraint group statements, where they exist.

When modifying an existing Pin constraint group, the text cursor can be placed anywhere within the document - you do not have to place the cursor within the relevant line for the statement.

A Pin constraint group can be added/modified by typing directly within the constraint file.

For more information about constraint files, refer to the application note 'Design Portability, Configurations and Constraints' and the 'Constraint File Reference', both of which can be found in the main FPGA Design section of the Help System.