You edit I/O attributes using the I/O Attribute Editor tool. This tool displays all assigned and unassigned I/O macros and their attributes in tabular format.
Use the I/O Attribute Editor tool to view, sort, select, and edit common and device-specific I/O attributes.
From the Tools menu, choose I/O Attribute Editor. You can view the I/O attributes by port or by package pin. Click the Ports tab to view I/O attributes by port name. Click the Package Pins tab to view I/O attributes by pin number.
Each row corresponds to an I/O macro (port) or a pin in the design, depending on the view displayed. The column headings specify the names of the I/O attributes in your design. The first four column headings are standard for all families so they will not change. However, the other column headings will change depending on the family you are designing for. For some I/O attributes, you will choose from a drop-down menu; for others, you might enter a value.
To edit I/O attributes:
Select an I/O standard for each I/O macro in your device.
Select I/O attributes that are available for your selected I/O standard.