lcd4linux-users

[lcd4linux] Re: LCD4linux - Backlight control

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

Hi Zsolt,

> I'm thinking about switching off the backlight on the lcd.
> Is there any way to control one or more "unused" wire on parport from
> lcd4linux?
> This could drive a transistor which could switch on or off the
> backlight.
> I mean a HD44780 or t6963 display, they haven't baclight control yet.

Well, that should be no problem. There's already a HD44780-"Model' which 
supports backlight-control by software (but with a special command, and 
in 4 levels).

I don't know how a circuit could look like. Any ideas?

I could implement an additional Wire for "Backlight", which could be 
turned on and off. (we have 1 or two wires free)

Is this what you want?


bye, Michael

-- 
Michael Reinelt <re...@eu...>
http://members.eunet.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781

[lcd4linux] Re: LCD4linux - Backlight control

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

Hi Zsolt,

>>I could implement an additional Wire for "Backlight", which could be
>>turned on and off. (we have 1 or two wires free)
>>
>>Is this what you want?

> Yes, it is. Exactly.
> How could this backlight control work? Should I restart the lcd4linux
> process to switch on/off the backlight with an another config, or can I
> send any kind of signal to the running process to switch this wire?

No, there would be a function called "LCD::Backlight(x)" with x being 0 
or 1, and a Config file entry specifying the initial backlight state. At 
the moment I have no ideas what to do with this funtion, this may be 
solved someday with events (and GPO handlers).


bye, Michael

-- 
Michael Reinelt <re...@eu...>
http://members.eunet.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781

Re: [lcd4linux] Re: LCD4linux - Backlight control

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

Hi there,

I just checked in software-controlled backlight for HD44780 displays.

To test it, do the following:

- specify a "Wire.BACKLIGHT" in the config file
- set an initial backlight value with the "Backlight" parameter in the 
display section

Any feedback would be appreciated.

bye, Michael

-- 
Michael Reinelt <re...@eu...>
http://members.eunet.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781