Re: [Lcd4linux-devel] Patch for multiple displays

[Stefan B. <st...@tr...>]

Hi Michael,

here's the patch:
---------------------------
--- drv_HD44780.c       2007-06-05 23:07:08.000000000 +0200
+++ drv_HD44780_new.c   2007-06-05 23:15:24.000000000 +0200
@@ -843,8 +843,9 @@
             currController =3D (1 << controller);
             break;
         }
-       row -=3D CROWS[controller];
      }
+    for (pos =3D 0; pos < controller; pos++)
+       row -=3D CROWS[pos];

      /* column outside of current display's width */
      if (col >=3D CCOLS[controller])

---------------------------

I didn't solve the problem with the control signals, i have to ask why
there are restrictions how they are wired.
For example, he has four displays and wants to set the four enable lines=

to DB4-DB7 and STROBE + RS to the control signals..

Greetings, Stefan



Am 05.06.2007, 22:09 Uhr, schrieb Michael Reinelt <re...@eu...>:

> Hi Stefan,
>
>> someone wanted to connect 4 displays at once, but it didn't work.
>> See here:
>> http://www.linuxforen.de/forums/showthread.php?t=3D235915
>
> Hmmm..... how did you solve the problem that you need 5 control signal=
s  =

> (4 enable, 1 strobe) but have only 4 (either the four "real" control  =

> signals or DB4..DB7?
>
> I know that theoretically we could use up to eight control lines (high=
  =

> data lines + control lines), but that would require some heavy  =

> modifications to the parport abstraction layer
>
>> The problem is in drv_HD_goto(int row, int col), file drv_HD44780.c, =
 =

>> line  839.
>> Here is a patch:
>
> Could you please provide a "real" patch (a context diff)?
>
>
> TIA, Michael
>