The I/O Attribute Editor window appears below the Package and World View windows. It functions much like a spreadsheet with sort, copy, and paste capabilities. This editor allows selection of variables such as I/O Standard, I/O Threshold, slew rate, and I/O Power-Up State, depending on the family targeted. You can also enter the capacitance of the load being driven. You can lock assigned pins for subsequent place-and-route runs allowing parallel development of the printed circuit board (PCB).
Use the I/O Attribute Editor to view, sort, select, and edit these attributes. Double-click a column heading to sort by that attribute. If you select a macro in the Assigned or Unassigned list box, it will also appear selected in the I/O attribute editor.