I'm using an NI 9402 (spec PDF here) in a cRIO which says it has LVTTL input (low voltage TTL, seems like 'high' is 3.3V) but maximum input voltage is 5.5V. Would it hurt to use a 'standard' TTL - customer says they have TTL on a BNC, which I think means 0.8V is low, and 5V is high. Maybe my issue is the 9402 says 0.8V is the maximum 'low'.
If not, I'd imagine I can just use a voltage divider or a COTS part?
Thanks! I'm more of a digital weenie - I just don't want to break this nice card 🙂
The spec actually says a maximum input voltage of 5.25V.
This is somewhat common with bidirectional DIO anymore that the input can accept TTL levels, but the output will be LVTTL levels. Since the thresholds are the same, there is no issue, assuming little to no current draw.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions Unofficial Forum Rules and Guidelines "Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God" - 2 Corinthians 3:5