Re: [Lcd4linux-devel] LCD4Linux I2C LCD

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

Hi Justin,

> Is there a list of I2C commands that would be preferred such that I maintain broad compatibility? I'm effectively using
> the 256x64 pixel screen as an 8 line character LCD. I think it would make the most sense to fall under the category of
> graphic, vs text, but I know I'm ready to move forward with text mode now.

It depends :-)

graphical displays basically just require one command, or better one functionality: copy an area of pixels to the 
display. All the text and widget rendering, bar handling, double-buffering stuff is done by lcd4linux. Take a look at 
some of the graphic drivers, and you'll find just one blit() function you need to implement.

For a text display, you need mre functions: a goto(x, y), a "put string" function, and all this "user-defined character" 
stuff. I am sure you don't want to do this user-defined char handling with your graphical display...

as I2c tends to be quite fast, a very simple approach could be to transfer a whole line of pixels at once, passing the y 
coordinate as the first i2c packet byte, followed by a bitmap of all pixels in that row (I just implemented something 
similar with a graphical display driven by a AVR connected cia i2c to another AVR board)


regards, michael

-- 
Michael Reinelt <mi...@re...>
http://home.pages.at/reinelt
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