Arcade Card Pro

4x KM48C512AT-7
1x HM628128ALT7
2x 84256A-70LL
1x Squarish (round edges) gloptop (probably AC chipset)
1x little smaller round gloptop (probably sys card ROM)

The PCB is long. It ends at the end of the ‘bump’. Two of the KM48C512AT-7 are on the top side of the PCB, right under the protective bump. The rest of the chips are on the bottom side. The chips sit fairly tall, so there’s no actually plastic for a large part of the card. Instead, there’s a thin plastic bridge running down the middle and a metal plate on the bottom of the card. It you look closely, you can actually see the outline of the edges of it.

So, 70ns FastPage mode DRAM. 512kbyte chips and four of them. The other three are SRAM chips. 128kbyte 70ns and two 32kbyte 70ns ones.

Oh, and the PCB is actually the thinnest I’ve seen for a hucard (yeah, I’ve take a few black PCB’s off the hucard plastic).

Still waiting on the government to approve my health insurance so I get a stop to this f-ing pain and reoccurring fevers. It’s pissing me off. For now, I’m living on overtaking naproxin and asprin.

6 Responses to “Arcade Card Pro”

  1. I’m really surprised it wasn’t all glop-top chips, very cool. And I’m surprised they used DRAM as well — sure it’s cheap, but the Arcade Card Pro was always so expensive I assumed it was SRAM. Very cool stuff, thanks for taking it apart and checking it out.

    Since it really is DRAM, maybe those CSLs in the ACD libraries were for earlier development hardware that had a simpler DRAM interface that needed slower access. Whatever it was, they certainly tuned it up for full-speed access in the final version. I’m impressed they coaxed as much performance out of the DRAM as they did without taking the easy way out of wait states (not really possible on the PCE) or forcing CSL mode.

    Likewise I’m surprised it was cheaper to use a 128K and two 32K chips to make up the 192K of system card RAM, rather than use a single 256K chip like the Super CD-ROM^2 does. Does the ACD Pro card predate it? If they already have a gate array onboard for the DRAM, surely they could throw in the moderately complex address decoding needed to fit 192K of 256K RAM in the area outside of the built-in 64K range of the IFU-30 unit.

    Hope you get feeling better! Living with pain is a PITA. Hang in there. 😀

  2. I could always take apart my Japanese SCD 3.0 card and see what SRAM chips it uses…. but taking apart the arcade card was scary enough. Not sure I want to do that to my little SCD card.

  3. Hi,

    please check your mail.

  4. I know this is an old post and all, but did you take photos of the PCB? I’m looking for more info on how the Arcade Card works, and haven’t found very detailed documentation on it. I know some of the emulators support it, but the source code I’ve read is rather convoluted and not well commented, so I was hoping to find further info on it. (If you know of any docs that describe how it’s addressed, etc., please also point me to those.) Thanks!

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