I need to use a multiplexer to connect a few switches. I think I'll be using the 74XX151 if that matters (by the way, what's the difference between all of them? I found an eagle file for the 74LS151N but I guess they're all pin-compatible).
I have never used one before so I really don't have a clue, do I need to use pull-up resistors to pull the pins high or can I use the internal ones in the atmega?
I tried searching for an answer but couldn't really find anything.