[Lcdproc] I2C-LCD with 2 enable lines

[Jannis Achstetter]

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Stefan Herdler schrieb:
| Hi,
| Carsten Tschense wrote:
|> Hi,
|> I already tried modifying the code and I ended up with this, which
|> displays the initial HD44780-message and then crashes:
|>
|> --- lcdproc-0.5.0/server/drivers/hd44780-i2c.c.old      2006-04-07
|> 16:54:29.000000000 +0200
|> +++ lcdproc-0.5.0/server/drivers/hd44780-i2c.c  2006-11-13
|> 15:50:37.000000000 +0100
|> @@ -72,12 +72,12 @@
|>  // HD44780_readkeypad
|>
|>  void i2c_HD44780_senddata (PrivateData *p, unsigned char displayID,
|> unsigned char flags, unsigned char ch);
|> -void i2c_HD44780_backlight (PrivateData *p, unsigned char state);
|> +// void i2c_HD44780_backlight (PrivateData *p, unsigned char state);
|>
|>  #define RS     0x10
|>  #define RW     0x20
|> -#define EN     0x40
|> -#define BL     0x80
|> +#define EN1    0x40
|> +#define EN2    0x80
|>  // note that the above bits are all meant for the data port of PCF8574
|>
|>  #define I2C_ADDR_MASK 0x7f
|> @@ -113,9 +113,9 @@
|>         PrivateData *p = (PrivateData*) drvthis->private_data;
|>         HD44780_functions *hd44780_functions = p->hd44780_functions;
|>
|> -       int enableLines = EN;
|> +       int enableLines = EN1 | EN2;
|>         char device[256] = DEFAULT_DEVICE;
|> -       p->backlight_bit = BL;
|> +       // p->backlight_bit = BL;
|>
|>         /* READ CONFIG FILE */
|>
|> @@ -154,7 +154,7 @@
|>         }
|>
|>         hd44780_functions->senddata = i2c_HD44780_senddata;
|> -       hd44780_functions->backlight = i2c_HD44780_backlight;
|> +       hd44780_functions->backlight = NULL;
|>         hd44780_functions->scankeypad = NULL;
|>
|>         // powerup the lcd now
|> @@ -221,9 +221,11 @@
|>         else //if (flags == RS_DATA)
|>                 portControl = RS;
|>
|> -       portControl |= p->backlight_bit;
|> -
|> -       enableLines = EN;
|> +       //portControl |= p->backlight_bit;
|> +
|> +       enableLines = EN1;
|> +       if (displayID == 0) enableLines = EN1 | EN2;
|> +               else if (displayID == 2) enableLines = EN2;
|>
|>         i2c_out(p, portControl | h);
|>         if (p->delayBus)
|> @@ -242,9 +244,9 @@
|>         i2c_out(p, portControl | l);
|>  }
|>
|> -void i2c_HD44780_backlight (PrivateData *p, unsigned char state)
|> +/*void i2c_HD44780_backlight (PrivateData *p, unsigned char state)
|>  {
|>         p->backlight_bit = ((!p->have_backlight||state) ? 0 : BL);
|>
|>         i2c_out(p, p->backlight_bit);
|> -}
|> +}*/
|>
|> Please don't laugh at me, I'm not saying I can code C... ;)
|>
| At the first glance looks almost like what I would have tried.
|
| I'm not an HD44780-expert but doesn't showing the "initial HD44780
| message" mean the init() function has been completed successfully?
| So the i2c_HD44780_senddata() has to be o.k. too (at least if the
| displayID is 0).
|> Suggestions?
|>

Hello there,

I just needed to do the same thing (40x4 over I²C) and I found out why
it didn't work you:
LCDd tries to set the backlight to 1, no matter if there's a
backlight-function or not. So, don't comment it out, don't set it to
NULL and just remove the contents. This way it worked for me ;)

Greetings,
	Jannis

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