> > Sparkfun (IIRC) had a nice tutorial on this, explaining the use of
> > voltage dividers, FET-based converters, etc.  However, there are also
> > MAX3232 versions that are specific to 3.3V power/logic, and some of
> > what you're interfacing to may have "5V tolerant" inputs, such as some
> > 3.3V PIC pins.
>=20
> Or rather 5V parts that have "3.3V tolerant inputs" ?
> Oftet through some Schmitt-trigger kind of inputs.
> The problem was that the PIC was at 3.3V and other stuff at 5V.

Such as 74HCTxxxx parts which have TTL level inputs, even though the chip i=
s running off 5V.

I would second the use of MAX3232 devices instead of MAX232 as they are 3v3=
 tolerant. They can be run at 3v3 or 5v on the digital side, so reducing th=
e stock of components required. IIRC pin for pin compatible to the MAX232, =
but require different value capacitors in the charge pump when used for 3v3=
 interface.


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