ALT_INBUF_DIFF in cycloneII

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That said, I have the strong feeling that setting pins to LVDS and powering the bank at 3.3V won't do what you need.

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Very simply, operation of the Cyclone II LVDS receivers isn't specified with 3.3V VCCIO, considering type and temperature variations. But I guess, it will work, at least in the RS422 speed range, though. As said, it's common mode range can't compete with true LVDS receivers and you have to care about keeping the maximum input voltage. I think, it can be an option for on-board communication, a single ended input would do in this situation, too.