Use the I/O Standard column to select an I/O specification for each pin.
If required to match the I/O standard, other I/O attributes, such as I/O threshold, slew, and loading, are automatically set to their default settings; you cannot edit these defaults.
You can change the I/O standards only for a generic I/O buffer to any of the legal I/O standards.
To specify an I/O standard:
Click the I/O Standard cell in the desired macro row.
Type or select a supported I/O standard from the drop-down list.
For devices that support I/O banks (for example, Axcelerator devices), the list is restricted to legal choices only. When an I/O is assigned, the I/O standards available for that I/O are limited to what the I/O bank location can support.
Note: Changing an I/O standard may also unassign existing I/Os. In addition, when a macro is assigned an I/O standard, the I/O bank is automatically assigned the voltages VCCI and VREF, if necessary. Unassigning this macro will undo these assignments as well.