Add Port 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=AddPort

Summary

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

Details

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

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

Adding a new Port constraint

If you wish to add a new Port constraint group to the file, simply type the name of the target port into the Target field. Use the Constraint Kind and Constraint Value drop-down fields to specify a particular constraint and its value respectively. 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=Port | TargetId=[Target field] | [Constraint Kind field]=[Constraint Value field]

For example, consider the case where a new port constraint is to be added for the top-level port MONITOR, in the FPGA design project and that the physical device pin number is to be specified (i.e. this port must be assigned to a specific pin of the physical device). In the Add/Modify Port Constraint dialog, you would enter MONITOR into the Target field, select FPGA_PINNUM as the Constraint Kind and then choose the required pin in the Constraint Value field. If we chose the pin number to be 188, the Port constraint group statement added to the file would be:

Record=Constraint | TargetKind=Port | TargetId=MONITOR | FPGA_PINNUM=P188

Modifying an existing Port constraint

If you wish to modify an existing Port constraint group within the file, simply enter the name of the port to be modified in the Target field.

If you want to modify the value for an existing constraint, select the entry for that constraint from the Constraint Kind drop-down field and then use the Constraint Value field to change the value as necessary.

If you want to add an additional constraint to the target port, simply use the Constraint Kind and Constraint Value fields to specify the constraint and its value respectively.

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 Port constraint group for the first time, the entry will appear below any other constraint group statements, where they exist.

When modifying an existing Port 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 Port 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.