> I've just read the fine print on the MAX3232 data sheet and found that the
> V+ reservoir capacitor on pin 2 may be taken to *either* Vcc or Gnd.
>
> However, there is an error associated with my use of this chip. I'd assumed
> that the transmitter inputs have pull-up resistors like the MAX202. They
> don't, and the unused input (pin 10) should be tied to Vcc or Gnd.
Ahhhhhhhh!!! I had a sinking suspision it might be something like that.
Enough noise from the charge pumps will leak into the input to make it
toggle and then the huge output current spike will probably cause it to
go back and then forward, etc.--at about the max toggle rate that the
chip can support. This will put a huge drain on the -V and +V, so that
the charge pump will effectively short Vcc to Vdd in their pumping efforts.
So, I'll tie the unused CMOS input to whatever supply rail is handy. Do
I need to do anything with the unused RS232 input?
So, maybe I'm *not* an idiot! There may be hope for me yet. :) Thank
you, Leon.
</ranton>
I find some of the Maxim data sheets labrentine and nearly impossible
to use. Can't some clever fellow use some macros and make a way to
split the 'master document' into specific manuals for each of the
chips therein described? I mean, come on, it's okay to support a few
simple variations of a chip in a manual (lpc210x), but there must be
some 20 chips in that datasheet! Some with more or fewer TX/RX channels,
some with low power standby, some with active RX channels in standby, and
many of them available in a dozen different packages--each with a
different pinout.
"What we've got here is failure to communicate. Which is the way he
wants it, well, he gets it. I don't like it any better than you."--
from "Cool Hand Luke"
</rantoff>
Cheers,
David