Description
No, Cyclone® III devices do not support OCT for 3.3V LVCMOS or 3.3V LVTTL I/O standards.
Due to the limited current strength of the 3.3V I/O buffer configuration, the output impedance can not meet the 25 Ohm or 50 Ohm OCT settings.
To interface Cyclone III devices with 3.3, 3.0, or 2.5 V systems, you can follow the guidelines provided in AN 447: Interfacing Cyclone III Devices with 3.3/3.0/2.5-V LVTTL/LVCMOS I/O Systems (PDF).