SparkFun Forums

[o3aaron]

This is probably a dumb question, but im using a rabbit uP. The I/O is 3.3 V. I want to hook up the serLCD to work with the rabbit. I know that it has to be +5 V to power the serLCD but to send it the information can I just use the serial ports on the rabbit? Can the RX pin on the serLCD take 3.3V?

[bsodmike]

Since it is TTL, normally 5v = 1 and 0v = 0, but usually anything over 2.5ish will register as 1, so it *should* work. You are better off using a FET as a level shifter though, or you could try them ICs from Maxim etc, but a FET is simple and would work quite easily.

[kaiki]

I use a 3.3V HCS08 to drive the SerLCD module and it seems to work just fine, just remember to tie both the 5V and 3.3V grounds together.
(although the FET soln is the way to go if you expect any fluctuations on the 3.3V line)