Mark Chauvin wrote :

> I tried it both ways.  The data sheet for the max232
> actually shows it tied to ground, but there's a
> footnote that it can also be tied to VCC.

Note that the cap is "just" used to store a specific
voltage level. As long as the voltage limit of the
cap isn't violated, it doesn't matter that much which
voltage level the *other* side of the cap is connected
to.

I *might* have some things to do with the startup
current of the voltage multiplier and so on, thought...

I'd *guess* that the recomendation is such so that
you get the lowest voltage over the cap during
normal use (the +15 V cap is connected to 5V and
the -15V cap is connected to GND). That would give
you the best lifetime and you can use a cap with
slightly lower voltage spec (= smaller and lower price).

But, the point is, that it will probably (under normal
conditions) work (or not work) but ways.

Jan-Erik.



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