Re: [ECOS] EDB7212 LCD support

[Fano Ramparany <Fano dot Ramparany at rd dot francetelecom dot fr>]

Lewin,

Basically there is a mapping between the LCD frame buffer
and a predefined portion of the RAM, which lets you write/read
in the LCD frame buffer as if you write/read in the RAM.
This mechanism is clearly described in the Cirrus Logic
Datasheet DS474PP1 that they ship you with the board in the
section 3.14 "LCD controller with support for on chip frame
buffer" at page 46 . There is also a description of how you could
program the LCD controller (screen dimensions, nb. of bits
per pixel, refresh rate,...) in section 3.14 "LCD Registers" at
page 79.

The eCos lcd_support.c file can be found in
...\RedHat\eCos\package\hal\arm\edb7xxx\v1_3_1\misc

I've done a quick (not dirty yet;-) extension for
displaying greylevel images I can send you if you want.

Fano


"Lewin A.R.W. Edwards" wrote:

> Hi Fano,
>
> >Has anybody extended the LCD support provided in eCos 1.3.1 for Cirrus
> >Logic EDB7212 board to display grey level images on the screen?
>
> Where did you find information on how to use the LCD support at all?
> Basically the only info I've found is a note in the configuration utility
> that says that enabling LCD support allocates 128K of RAM. Thus far I have
> no idea where that RAM is, is there a symbol that points to it?
>
> I presume that the way to get grayscale is to enable LCD support (which
> allocates the full 128K of RAM for the LCD frame buffer) then manually poke
> the LCD controller registers for the desired LCD size and bit depth.
>
> Our system is driving a 320x240 color display, which is effectively a 960 x
> 240 grayscale display, so I will have to solve the same problem myself.
>
> Lewin A.R.W. Edwards (Embedded Engineer)
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