The I/O Attribute Editor displays four common attributes for all I/O macros:
Port Name indicates the I/O macro name.
Macro Cell indicates the type of I/O macro.
Pin # indicates the current pin assignment.
Locked, if checked, indicates that you cannot change the current pin assignment during layout.
Besides the common I/O attributes, the I/O Attribute Editor displays device-specific attributes such as I/O Standard, Skew, and Output Load. Only attributes applicable to a specific device appear in the I/O Attribute Editor table.