Forum Discussion
Altera_Forum
Honored Contributor
15 years agoIt depends on the inout level specification of the connected part. Many devices have a LVTTL specifiaction (about 1.6V Vih), they can be driven by 2.5V CMOS as well. Devices witha a 3.3V LVCMOS specification (Vih = 0.7*3.3V) in contrast typically work, but don't achieve a sufficient level margin, so a level translation IC should be used.