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Thread: Differences between PDS slots

  1. #1
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    Default Differences between PDS slots

    I seem to remember that's what they were called. The SE had a version, the IIsi another. The LC's still another. They may vary in name. The ones based on the 68030 are simply different physically or otherwise?

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    IIsi and SE/30 are the same just flipped around. An Ethernet card that works in the IIsi will work in an SE/30.

    IIci and equivalents are what all the Daystar Processor upgrade cards were made for.

    The SE's slot is unique.

    The Quadra 68040 ones are interchangable.

    I think all the LC PDS slots are compatible.
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    But for the most part these cards directly access the various uP buses, signals. So ... if you wanted to utilize such a card in say an Atari ST (granted the ST would need a 68020/68030/040), the only thing stopping is the firmware incompatibility.

    And to whatever degree would the extraneous video card:s firmware be tied to the native Mac firmware?

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    Quote Originally Posted by tipc View Post
    But for the most part these cards directly access the various uP buses, signals. So ... if you wanted to utilize such a card in say an Atari ST (granted the ST would need a 68020/68030/040), the only thing stopping is the firmware incompatibility.

    And to whatever degree would the extraneous video card:s firmware be tied to the native Mac firmware?
    This is the hard part. Electrically a card meant for a 68020 or higher ST or Amiga could probably be "adjusted" to work in a similar processor generation Mac's PDS slot, but Macs have *very* specific ideas about what the memory map needs to be for expansion cards to work seamlessly, and every Mac card (at least if you want it detected by the plug-and-play architecture) requires a "declaration ROM" in a specific format that incorporates information describing the card's resources and supplying the necessary driver code for basic functionality. It is *possible* to build a card for PDS that breaks most of the rules (as long as it only occupies memory addresses that will never stomp on the Mac's built-in hardware in *both* 24 and 32 bit addressing modes), but such a card will require an oddball driver that's going to be genuinely difficult to write.

    The details are *reasonably* well documented in the various "Inside Macintosh" and other developer manuals. The main reference actually has most of the details for building a specific low-spec video card in it; the example interfaces to Nubus, but the firmware details are identical for PDS.

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    Great reply, but uim you read me backwards. I'd be interested in using a Mac card with an Atari. But first things first, the Atari would need a processor upgrade, as I don't have a TT030 or Falcon.

    I suppose I should just get a different computer . I have half a mind to "split" a 520stfm board into 2 stacked boards. Or whatever. It really never ends (or begins!) once my devious mind starts planning things.

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    Oh, yeah.

    So, I think in that case you might be in a worse position. I don't know a lot about the ST series, but my vague understanding is that most models are at heart 68000 machines, even to some degree most of the models that shipped with bigger CPUs. (IE, in terms of bus layout and signals I think a "Falcon" is basically just an ST with a CPU upgrade built into it.) I suspect you'd have a difficult time adapting *any* 32 bit PDS card to it. Might have better luck with LC cards, but the IO/memory mapping is still likely to be wrong enough that you'd be better off starting from scratch.

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    Quote Originally Posted by Unknown_K View Post
    I think all the LC PDS slots are compatible.
    Like with all Apple slots, not really.

    The Macintosh LC and LC II had a 96 pin PDS slot, which every other system based on these two designs also used. The Macintosh LC III and III+ had a 110 pin PDS slot. The reason for the extra pins is because the bus width was doubled from the crippled 16 bit to the full 32 bit bus the 68030 was designed for and the PDS slot needed the extra pins for 32 bit support.

    PDS cards designed for the 110 pin "extended" PDS slot will not work on the older 96 pin slots and while the 110 pin slot was designed to be backwards compatible with 96 pin PDS devices, compatibility varied by manufacturer.

    If you have an LC III or III+, you'd want to find 110 pin PDS cards because they're a whole lot faster.

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    I had thought I had a line on Radius Pivot monitors, but it may not pan out. So the point is moot at this point. Glad to see so many knowledgeable Mac psychos though.

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    Quote Originally Posted by GiGaBiTe View Post
    PDS cards designed for the 110 pin "extended" PDS slot will not work on the older 96 pin slots and while the 110 pin slot was designed to be backwards compatible with 96 pin PDS devices, compatibility varied by manufacturer.
    I have a Sonnet Presto Plus accelerator that's 110 pin, but it's designed specifically to work with 96 pin as well. Compatible with the LC through the LC III. I never thought to compare speed between my LC and LC III, and it's peaked my curiosity. Unfortunately I don't have an LC III anymore. I wonder if the extra pins would mean faster ethernet performance on the LC III. Would be hard to benchmark since the LC III also had a 32-bit bus and wasn't crippled like the LC.

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    Quote Originally Posted by olePigeon View Post
    I have a Sonnet Presto Plus accelerator that's 110 pin, but it's designed specifically to work with 96 pin as well. Compatible with the LC through the LC III. I never thought to compare speed between my LC and LC III, and it's peaked my curiosity. Unfortunately I don't have an LC III anymore. I wonder if the extra pins would mean faster ethernet performance on the LC III. Would be hard to benchmark since the LC III also had a 32-bit bus and wasn't crippled like the LC.
    The Presto Plus has RAM onboard so I don't think processing would be any slower unless it has to use the motherboard RAM. LC SCSI and Video is slow enough that 16/32 bit interface doesn't make a difference.
    What I collect: 68K/Early PPC Mac, DOS/Win 3.1 era machines, Amiga/ST, C64/128
    Nubus/ISA/VLB/MCA/EISA cards of all types
    Boxed apps and games for the above systems
    Analog video capture cards/software and complete systems

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