Re: Accelerator / VGA Graphics card

[Sheldon Simms <sheldonsimms@yahoo.com>]

On Wed, 22 Oct 2003 23:06:07 -0400, Lee Cremeans wrote:

> Sheldon Simms wrote:
>> On Wed, 22 Oct 2003 19:54:34 -0400, Charlie wrote:
>> 
>> 
>>>"Wayne Stewart" <waynes@telus.dotnet> wrote in message
>>>news:K%Dlb.1279$SJ1.826@edtnps84...
>>>
>>>>
>>>>Exegete wrote:
>>>>
>>>>
>>>>>Which is a good argument for a PowerPC based accelerator, as there is
>>>>>already Bernie II the Rescue, which emulates ALL the IIgs in software.
>>>>>Surely doing just the 65816 should be easy.
>>>>>
>>>>>Roy
>>>>
>>>>I don't think it'd be a lot easier, there's emulaters for PCs too.
>>>>Personally I like the idea of a G3 based card because so many G3 0wners
>>>>upgraded their computers that you can get the chips for next to nothing
>>>>or for free if youhappen to know a lot of Mac owners. There's likely an
>>>>equivalent out of date PC processor.
>>>
>>>Could these chips run with the power restrictions of an Apple II?
>> 
>> 
>> No. And in fact, the Pentium M may be a problem as well. Some
>> Pentium M configurations are quite low power, but seem to
>> require active cooling anyway.
>> 
>> A Transmeta Efficieon can supposedly operate with only passive
>> cooling, which indicates even lower power requirements.
>> 
>> I can't see any way a PowerPC of any kind fits the requirements.
> 
> Have you thought about using something ARM-based, like the newer Intel 
> xScale chips? I was reading up on the PXA255 tonight after spotting this 
> thread, and they include quite a few goodies that could be useful (like 
> integrated RAM interface, AC97 support, PCMCIA/CF interface and an LCD 
> controller).  Runs at up to 400 MHz and only pulls 2.6 watts of power 
> worst-case.
> 
> They have a product brief up at 
> http://developer.intel.com/design/pca/prodbref/252780.htm if you're 
> interested.

I did think about it a bit. Actually I would prefer not to have things
like AC97, PCMCIA, and LCD controller. I think a very restricted
focus is necessary to prevent feature explosion in a project like
this. Having said that, extra hardware capabilites wouldn't rule out
any chip as far as I am concerned, as long as their availability is
incidental to the decision to go with the chip.

The reason I started this thread is because I liked the features
available with the two-chip solution I originally mentioned. On
two chips you get the processor, memory controller, and graphics
controller. Add a SO-DIMM and a Flash ROM, and the basic structure
of the card is complete.

The Transmeta Efficion is also an interesting possibility. It has
an integrated memory controller and AGP controller. It would only
be necessary to add a graphics controller (perhaps an older chip
like an ATI Rage Mobility) to complete the package. Unfortunately
there aren't any detailed technical specifications available yet
so I don't know what the power requirements are. They should be
similar to the Crusoe, though. So you might be able to get an
Efficeon running at ~700Mhz for 5W.

As for the XScale, I don't really have anything against it. In fact
I brought it up myself the last time this sort of thing came up.
I do think an x86-based solution would have development easier,
however, since most of it could be done on a standard PC. I have
also heard that the performance of the XScale leaves something to
be desired, even though the core frequency is relatively high.