[comp.sys.ibm.pc.hardware] 24 bit Colour Boards for ATs

graeme@research.canon.oz.au (Graeme Wong See) (03/08/91)

I am curious to know if there is a general architecture for 24 bit colour
boards for an AT bus PC. By this I mean ...

1) Is there a standard place in memory to put the board and how big is this
	memory allocation

2) If the memory allocated is a 64k chunk then do they bank switch the rest
	of the memory and what I/O address do they use for the bank switch
	register.

3) Is the memory setup a packed pixel (rgb for each pixel) or 1 bit planar
	(ie 24 1 bit pixel planes) or 8 bit planar (ie all red pixels, then
	green then blue)

4) If it's a packed pixel, then do people ignore the 4th byte or do the	use
	it as an "alpha" channel.

5) What resolutions do they provide and do they emulate EGA/VGA screens.

6) Do they use DRAMs or VRAMs.

What I'm basically after is how commercial 24 bit colour boards work. If you
have any details on these boards (Targa, Vista, etc etc) or the above
questions, I'd be most grateful.


graeme
 
-- 
Graeme Wong See, Hardware Engineer           | Net:  graeme@research.canon.oz.au
Canon Information Systems Research Australia | Phone: +1 61 2 805 2912
P.O. Box 313 North Ryde, NSW, Australia 2113 | Fax:   +1 61 2 805 2929