Tim Schmidt wrote:
Huh? What are we discussing here?
What I am discussing is using existing chips to do part of the design.
the open-graphics project is about creating a fully documented
graphics chip, the kind that can be added to an already functional
computer... I'd like a bit more than a framebuffer and basic VGA.
If we can start with a memory controller, frame buffer, video
controller, interface for the GPU (I think that using the AGP backwards
would work), and VGA hardware in an existing chip, this should be less
expensive than reinventing that wheel.
An issue is where and how to interface to the host computer.
If the SiS GPU is fully documented, then it could also be used. so, I
am talking about two different possibilities.
I am specifically considering the 741 series for a card that had an X
server on board since a Geode NX might not be less expensive enough to
use just to boot the NorthBridge chip.
For a card that did not have the X server on board, perhaps a SiS 661 or
662 series NorthBridge would also be suitable. It would depend on
whether the Pentium or AMD Athlon bus was easier to use.
The other possibility is the AMD 761. This does not have a Video
Controller or VGA hardware. So, I wonder if this would be enough of the
design to be worth the cost. It does have a PCI but it is only 32 bit @
33 MHz.
Do you think that DDR vs. DDR2 memory is an important issue?
I am aware of the various cost vs. quantity issues. A custom chip would
take the least board space. However the economies of scale require the
highest quantities for a custom chip and the lowest quantities for
existing chips and custom boards. Also, less board layers could mean
less cost per board even if the boards were larger.
--
JRT
_______________________________________________
Open-graphics mailing list
[email protected]
http://lists.duskglow.com/mailman/listinfo/open-graphics
List service provided by Duskglow Consulting, LLC (www.duskglow.com)
