2008/1/7, David <stopthegop@...>:
>
> Very coincidental that this obscure topic should come up! I happen
> to have an X-Calibur board. The other day I was reading the readme
> file on the driver disk that came with the X-Calibur and it gave me
> an idea. According to the doc, the X-Calibur is "designed to be
> fully upward compatible with the 'soon to be released' 68060
> processor from Motorolla". That got me thinking. Hmmm.. Does that
> mean the X-Calibur could (in theory at least) ride atop, say, a
> CyberstormPPC card?? Just out of curiosity I checked the orientation

It depends on where x-calibur maps the 128MB. The PPC probably won't
be able to address the additional memory.

> of the chips on the two boards and how this might be done. And you
> know what? They line up *almost* perfectly! I say almost because
> the X-Calibur would barely clear the PPC with a small heatsink,
> leaving no room for a fan. A platine or riser of some sort would
> have to be built to raise the X-Calibur enough so that the PPC could
> breathe. The other issue(s) I can forsee would be to make sure the X-
> Calibur does not feed the 68060 +5V. Power would have to be
> converted to +3.3V for the 060. The memory on the X-Calibur (4x72

I don't know if you have compared a 040 and a 060 chip but 060 has
some extra rows of pins. In addition to that, it's not as easy to
adapt a 040 board to use a 060, otherwise people would be using
WarpEngines with 060 chips and would get much better memory speeds
than using phase5 boards

> pin SIMM 32M/each) should be easily addressable by the Cyberstorm,

What makes you think it would be easily addressable by the CSPPC? I
don't think the PPC can address that memory as the CSPPC memory
controller isn't designed for that.

The CSPPC may map other stuff in the memory area used by the
x-calibur, don't forget that x-calibur is a slightly "hacky" board,
designed to work with A3640.

> right? Same as if I had a DKB3128 plugged into a Zorro slot. Also,

It's not the same as you are connecting something between the 680x0
and the memory controller and not outside that memory area. The PPC
e.g. will have hard time discovering that on address 0xWhatever
connected to some pins of the 680x0 there's a memory expansion. I
don't know how it autoconfigs but in case you got it working with a
040 CSPPC I doubt the PPC chip would be able to address that memory
and of course, OS4 wouldn't be able to use it.

> the BlizzardPPC can address 256Meg so I see no reason why the
> Cyberstorm couldn't. It sounds kind of crazy but after considering

The memory controller of the CSPPC isn't designed to do that.
BlizzardPPC has supported 256MB since the beginning and CSPPC hasn't,
despiting the fact that it was updated and its programable logic
reprogrammed. Even the unreleased update that corrected DMA transfers
with G-Rex didn't address more than 128MB.

> this a bit, I actually believe this could work.
> Comments/feedback/assertions of insanity are more than welcome on my
> idea.
>
Since simms eat a lot of power you'll risk the power traces of your PPC card.

memory addresses may collide as the CVPPC slot has more than 1.5GB of
space reserved IIRC.


--
Saludos/Best Regards
Jaime Cagigal