While the internal addressing of the HD44780 appears capable of
handling up to 64 columns, the hardware itself can only electrically
drive up to 40 columns, and in fact can only drive 40x2 per HD44780.
The 40x4 display you are looking at uses two HD44780 chips, one for
the top 40x2, and one for the bottom 40x2 - it has two enable pins to
address the separate chips.

If you want more than 40 columns, your best bet is to move to a
graphical display.  You might even consider adding a Parallax
Propeller chip to your project to emulate an HD44780 and output VGA,
but there are many other options if you want to retain HD44780
compatibility with a larger display.

-Adam

On Thu, Aug 13, 2009 at 2:16 AM, PicDude<picdude2@avn-tech.com> wrote:
>
> Looking for a character LCD with a relatively standard HD44780 type contr=
ol
> protocol. =A0Largest (max chars) I've found is 40x4. =A0From the way the =
HD44780
> is addressed, I expect someone should make LCD's with 64 columns. =A0Anyo=
ne
> know of one that exists?
> Thanks.
>
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>
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