i guess with the right amount of intelligence / time /money anything is
possible :)





On Mon, May 13, 2013 at 12:47 PM, Jeff Walther <[email protected]> wrote:

>
>
> On Monday, May 13, 2013 7:31:54 AM UTC-5, Derek Morton wrote:
>>
>>
>> True enough...  It would seem Robert was able to install the DOS card in
>> his Centris and everything worked.
>>
>> I was lamenting over the inability to use the PPC x100 4MB PDS video card
>> in a Quadra PDS slot.  Whenever I am working with my Quadras I grumble over
>> the lack of PDS expansion cards.  I am perpetually tempted to make one (I
>> even went out an purchased a large number of the PDS card connectors from a
>> parts broker) but I never seem to have the time to get around to more than
>> doodling up a circuit or two.  Life always seems to take precedence...  And
>> how much longer before the Quadras start to die?  I think the better
>> project would be to reverse engineer the PALs/GALs used for glue logic...
>>  Programmable devices scare the heck out of me!
>
>
> The PPC X100 machines  had a 64 bit data bus.  The Quedras had a 32 bit
> data bus.   It would be non-trivial to adapt the X100 PDS video card to
> work in a Quadra.   My understanding is that the X100 PDS Video card is
> just a dumb frame buffer, but that it is very very fast, because it has
> excellent bandwidth -- full 64 bit datapath and 32 bit address bus, and
> they're not multiplexed (sharing wires) the way they would be if they were
> PCI or NuBus.
>
> f you built a nice Quadra PDS  frame buffer card, you could probably
> extract the proportional performance out of the Quadras.  The last time I
> checked the Texas Instruments THS8135 and THS8200 DACs are still available
> for less than $10 each.  Come up with some video memory, and logic to tie
> the Quadra bus to the VRAM, and march the bits out to the DAC, and a
> declaration ROM and you could build a pretty nice PDS card for the Quadras.
>
> BTW, where did you find the compatible Quadra PDS connectors.  I have not
> looked really hard, but my desultory searches never turned any up.
>
> Jeff Walther
>
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-- 
Charles

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