Re: [lcd4linux] Non-uniform displays

[Ernst B. <e.b...@xe...>]

Hi Michael,

thanks for the fast answer,

On Tuesday 18 July 2006 22:22, Michael Reinelt wrote:
> > I was wondering if its possible to use non-text and non-graphic displays
> > with LCD4Linux.
>
> Sure it's possible. But it's a bit of work...

Well, thats great news, even if its a bit of work, it sure beats coding "yet 
another linux LCD controller framework" ;)

> > It has a 5 digit alphanumeric display (14 segments each), a two digit
> > numeric display (7 segments), some special symbols for equalizer presets
> > and such, as well as 5 bargraphs, 11 segments.
>
> The symbols are easy to implement: just add them as GPO's. I've done
> this with displays from mobile phones, works great. If there are symbols
> that are grouped together (just like "battery level" or "signal
> strength" on mobile phone), you can group them in lcd4linux, too. Either
> use an integer value (to control the 'level', but not every single bit)
> or a bitfield (that's what I'd prefer)
>
> for the 7 and 14 segments, you'd have to write your own "rasterizer". It
> should be possible to display all alpha chars on a 7-segment display
> too, but you'd have to mix upper and lower chars.

Thanks for the hints, I'll have a closer look at the API. At first I was 
wondering 'cause the driver development wiki page lists a examples seperated 
by "text" and "graphic" LCDs...

> Probably it would make sense to write a "generic" rasterizer for this
> stuff, but as a starting point I'd recomment not to take care of this
> but implement all in the driver. We could extract the generic stuff later.

Well, that part will probably be just a lookup table for charcode => bitfield 
describing the "font".

> I've got a mixed graphic/7digit display too, but never could find the
> time to control the 7digit stuff....

Mine was sitting in a box for half a year, hardware+firmware mostly done, but 
the linux driver part was completely missing. But now I finally found some 
time for it again.

Btw, if someone's interrested in the schematics/firmware (AVR Based), I'll be 
happy to publish them. Most parts are quite generic and might be of use for 
everyone trying to drive a VFD from his PC. (Voltage regulator for 
Filament+Anode, grid drivers, ...)
 

> If you need any help, please let me know.

Surely will ;)

> bye, Michael

Greetings,
/Ernst