2.5.17. 1.05 V, 1.1 V, or 1.2 V I/O Interface Voltage Level Compatibility
1.2 V LVCMOS I/O Standard Voltage Swing Calculation
If you use the 1.2 V LVCMOS I/O standard, the output signal swings from 0 V to 1.2 V on a lossless transmission line with no external pull-up or pull-down component. Ensure that the VIH or VIL tolerance of the downstream connecting device can meet those conditions.
1.2 V Voltage-Referenced I/O Standards Voltage Swing Calculation
If you use the 1.2 V voltage-referenced I/O standards, the output signal swing has a dependency on the external board termination or the internal termination of the receiver.