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 -- -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/ --- You received this message because you are subscribed to the Google Groups "Vintage Macs" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
