Forums

screen resolution cPCI

Started by Jan April 28, 2004
Hi,

We have a cPCI board with DVI output.
Build a DVI -> tft converter with TI chip TFP401.
The tft display we use has a resolution of 640x480.

When we start the board we see the bios start up.
But we only see a part of the screen in the 3rd quadrant of the screen.
1|2
4|3

The image we see must be shifted to the left and to the top.
Seems as if the cPCI card is always running with a resolution of 
1024*768. And the 640*480 is centered on this screen. ??

The chipset on the cPCI board is Intel 82815


Hope anyone can help me with it.

Thanks,

Jan
> When we start the board we see the bios start up. > But we only see a part of the screen in the 3rd quadrant of the screen. > 1|2 > 4|3
The board must have a CMOS setup option to select LCD resolution. If not, you need a new BIOS from the board vendor.
On Wednesday, in article
     <c6oume$2d2$1@news1.tilbu1.nb.home.nl> nomail@noma.il "Jan"
     wrote:
>Hi, > >We have a cPCI board with DVI output. >Build a DVI -> tft converter with TI chip TFP401. >The tft display we use has a resolution of 640x480. > >When we start the board we see the bios start up. >But we only see a part of the screen in the 3rd quadrant of the screen. >1|2 >4|3
VESA specs dictate that at system startup _complete_ displays (CRT/LCD) will always start as 640 x 480, whatever the resolution of the actual display. The display must be able to display 640 x 480. How it achieves this ENTIRELY upto the display device. It is up to you to work out how to handle the timing centreing, scaling, shifting method you use at this resolution. If you do not have the DDC ROM (actually I2C EEPROM) for the display controller to read or setup correctly the display controller could be sending any number of 640x480 timing signal formats.
>The image we see must be shifted to the left and to the top. >Seems as if the cPCI card is always running with a resolution of >1024*768. And the 640*480 is centered on this screen. ??
Maybe the cPCI card is getting confused about what your display is actually doing.
>The chipset on the cPCI board is Intel 82815 > >Hope anyone can help me with it.
I would suggest getting the VESA specs before proceeding any further to understand what you have to do. They can even be ordered online and some of the outline information is available online. -- Paul Carpenter | paul@pcserv.demon.co.uk <http://www.pcserv.demon.co.uk/> Main Site <http://www.gnuh8.org.uk/> GNU H8 & mailing list info. <http://www.badweb.org.uk/> For those web sites you hate.