[Lcdproc] I2C-LCD with 2 enable lines

[Markus Dolze]

Hell again,

I had a look at the i2c and winamp wiring driver. The part that distributes the data to the two controllers is in the hd44780 driver itself, not in the wiring driver.

The i2c does only use one enable line. If you connect the display's second enable line to P7 pin on the part extender (without the connection to VCC of course!), you may modify the i2c_HD44780_senddata to use the DisplayID to talk to different controllers similar like the winamp wiring driver does.

Regards
Markus

-------- Original-Nachricht --------
Datum: Sun, 12 Nov 2006 13:37:55 +0100
Von: "Markus Dolze" <bsdfan@nurfuerspam.de>
An: lcdproc@lists.omnipotent.net, carsten@michaeli-gymnasium.de
Betreff: Re: [Lcdproc] I2C-LCD with 2 enable lines

> Hello,
> 
> I found this display at www.pollin.de. They also have some documentation
> (in german only) and sample code available.
> 
> >From what I read it should be straightforward to connect this display to
> a standard PC's parallel port using Winamp wiring style, which supports
> vertically spanned displays.
> 
> The i2c-driver currently does not support vertically spanned displays with
> more than 1 controller. 
> 
> I guess you have to use i2c because the nslu2 does not have anything else,
> right?
> 
> Regards
> Markus
> 
> -------- Original-Nachricht --------
> Datum: Sun, 12 Nov 2006 10:31:23 +0100
> Von: Carsten Tschense <carsten@michaeli-gymnasium.de>
> An: Markus Dolze <bsdfan@nurfuerspam.de>
> Betreff: Re: [Lcdproc] I2C-LCD with 2 enable lines
> 
> > Hi,
> > it's a Wintek WD-C2704M-1HNN 27x4 with two seperate controllers for the
> > first an the last two lines.
> > The i2c-driver doesn't support two displays because the last pin of the
> > i2c-port-extender is usually used to control the backlight.
> > 
> > I already tried modifing the driver, but it didn't go that well... I'm
> > not a c programmer and don't know the driver modell... I'm using the
> > adress of the pin former used by the backlight for the second enable
> > line, the init-function looks well, too. Now: if displayID == 0 we're
> > writing on both controllers??
> > 
> > Regarding the contrast-problem: yes, it controls the contrast.
> > 
> > 
> > thanks,
> > Carsten
> > 
> > Markus Dolze schrieb:
> > > Hi,
> > >
> > > What type of display (manufacturer, modell) do you have? How many
> colums
> > does this display have, 20 or more? 20x4 displays usually do not have a
> > second enable line.
> > >
> > > AFAIK, the hd44780 driver (and it's i2c wiring driver) do only support
> > vertically spanned displays. That is two or more displays which are
> arranged
> > vertically to create a virtual display with more lines.
> > >
> > > Does anybody know if the i2c wiring supports several displays
> connected
> > to i2c port?
> > >
> > > Or am I wrong and the i2c-driver is something different than hd44780
> > with i2c wiring?
> > >
> > > Regards
> > > Markus
> > >
> > > -------- Original-Nachricht --------
> > > Datum: Sat, 11 Nov 2006 20:16:25 +0100
> > > Von: Stefan Herdler <herdler@gmx.de>
> > > An: Carsten Tschense <carsten@michaeli-gymnasium.de>,
> > lcdproc@lists.omnipotent.net
> > > Betreff: Re: [Lcdproc] I2C-LCD with 2 enable lines
> > >
> > >   
> > >> Carsten Tschense wrote:
> > >>     
> > >>> Hi,
> > >>> I've got a LCD without backlight and 4 rows and I'm using the
> > i2c-driver
> > >>> on a nslu2.
> > >>> I connected EN2 to P7, which is usually used for the backlight, but
> I
> > >>> was not able to change the driver-code to use all 4 rows :-/
> > >>> Can anybody help me? =)
> > >>>   
> > >>>       
> > >> The file for your wiring is /server/drivers/hd44780-i2c.c.
> > >> The information you're searching must be in the function 
> > >> lcdstat_HD44780_senddata() of /server/drivers/hd44780-4bit.c. It's
> the 
> > >> enableLines stuff, I guess.
> > >> It`s only a little hint (it's all I can do without such a display)
> but
> > i 
> > >> hope it helps.
> > >>     
> > >>> By the way, the display gets totally messed up (strange characters)
> as
> > >>> soon as I lower the contrast with the potentiometer - the display
> only
> > >>> works when the contrast is at maximum - any ideas?
> > >>>   
> > >>>       
> > >> There's something wrong with the wiring, I guess.
> > >> Does the contrast-potentiometer only mess up the display or does it 
> > >> control the contrast too?
> > >>     
> > >>> thanks,
> > >>> Carsten
> > >>>
> > >>> _______________________________________________
> > >>> LCDproc mailing list
> > >>> LCDproc@lists.omnipotent.net
> > >>> http://lists.omnipotent.net/mailman/listinfo/lcdproc
> > >>>
> > >>>
> > >>>   
> > >>>       
> > >> Stefan
> > >> _______________________________________________
> > >> LCDproc mailing list
> > >> LCDproc@lists.omnipotent.net
> > >> http://lists.omnipotent.net/mailman/listinfo/lcdproc
> > >>     
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