Re: [Lcd4linux-devel] DOG-M via I2C on WRAP

[Luis.F.Correia <Lui...@se...>]

Hi Stefan, 

> -----Original Message-----
> From: Stefan Krister [mailto:ste...@cr...] 
> 
> Hi Folks,
> 
> yesterday my DOG-M awaked from death ...
> 
> There are 14 init-nibbles to send. Without them, the LCD keeps dark.
> There are instructions for setting 5 bits of contrast-level, 
> internal bias, booster, amplifier and follower (what ever 
> that means ...) and the usual things like 'display on', 
> 'cursor home', 'display clear', 'display size' and so on. If 
> you like to help me, take a look into the datasheets at [1] and [2].
> 
> I managed to do a 8bit init via dip-switches ... and it 
> awakes! Then I wrote a shellscript to do the same with 4bit 
> and it worked too.

Congratulations!

> 
> After initialisation lcd4linux runs on the display. I made a 
> few pictures, view it at [3].
> 
> But ...
> 
> I2C _is_ slow. No way to have scrolling lines by now.
> Luis, what about your 8bit (2x PCF8574) experiment? May I 
> have your details? Adressing, configuration, schematics?

Well, the 8bit version was really just an experiment... It is
still slow. But it depends on the actual timings on the
scx200 driver, one could alter them a bit to make it slightly
faster.

As for the 2xPCF8574 schematics, I have none, but it is basicly 
just using one as the 8bit output, and the other for the
EN and RS bits. But there is a lot of code to be written inside
lcd4linux, as we'll need to separate the 4bit from the 8 bit
routines.

> 
> The DOG-M seems to use a different way for adressing the 
> positions on the display. I've one with 3 lines / 16 
> characters and one with 2 lines / 16 characters. Maybe my 
> init isn't correct by now. I'll keep trying more.
> 
> By the limits of the WRAP-Board, I'll try to plug the DOG-M 
> on the GPIO-header too. There are 7 gpio pins to use. I 
> think, that I could use parts of the "Routerboard" or 
> "Soekris" code for that.
> 
> But how to integrate into lcd4linux? By now, I think I should 
> add a new 'Model' to the HD44780 section. 

You could do as Martin Hejl has done, create a 'ppdev emulator'
driver. Check out http://soekris.helj.de for some details.


> Is that the right 
> way? I want to have the init-sequence once for both 
> wiring-variants. I want also to have the contrast setting by 
> configuration. Maybe one wants to plug a DOG-M via parport or 
> USB at 5V - it's possible and the init should work for that too.
> 
> [1] german: http://www.lcd-module.de/deu/pdf/doma/dog-m.pdf
> [1] english: http://www.lcd-module.de/eng/pdf/doma/dog-me.pdf
> [2] http://www.lcd-module.de/eng/pdf/zubehoer/st7036.pdf
> [3] http://gallery.port23.de/v/bastard/wrap/lcd/
> 
> MfG
> 
> Stefan

Luis Correia