Re: [lcd4linux] GPO circuitry

[Michael R. <re...@eu...>]

Hi Aragon,

> With some logics added to the circuit I think I can allow for these
> criteria:
> 
> 1.  Ability to use a 40x4 display
> 2.  Ability to software control the backlight on a 40x4 display
> 
> I think I can do it so that it'll be compatible with existing HD44780
> driver code for everyone that currently uses Winamp style 8 bit
> connections.  Basically it'll work like this:
> 
> On parallel port...
> 
>   set pin 1 high to strobe 44780 #1
>   set pin 17 high to strobe 44780 #2
>   set pin 1 and pin 17 high to strobe backlight controller
> 
> What do you think?

Should be no problem in hardware, but at the moment this is not 
supported in software. AND there's another problem: Some commands 
(clear, init, character define) go to _both_ displays at the same time, 
just by rising _both_ enable lines.

bye, Michael

-- 
Michael Reinelt                                   Tel: +43 676 3079941
Geisslergasse 4                                   Fax: +43 316  692343
A-8045 Graz, Austria                          e-mail: re...@eu...