Amiga 1000, ACA500+, ACE1K

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Don't Panic. Please wash hands.

    First off, I know this isn't recommended, but a friend loaned me his ACA500+ to play with, and I've been trying it out with my (US/NTSC) Amiga 1000. Hooking it directly to the A1000 meant it really wouldn't start up but 1 in 20 times, and would frequently freeze up a few minutes after it started, it if did make it to start up. But here's the fun part: putting a SupraDrive 4x4 side car between the ACA500 and the A1000 made it stable. Starts up every time. Stays up. I got the idea from reading an instruction from some other supplier from 1990 or so, about their product being more reliable when it went A1000 + ram expansion + the vendor's product. Anyway, in case that helps anyone....


    But... there are hints here and there about an Amiga 1000-specific version of the ACA500+. This google translated one for example:

    -----

    ACE1k is in the planning phase. Small Race with the Quartz Maker: I'd like to hold the first proof-of-concept board in hand when the special parts I need to generate a synchronous 28MHz clock externally for the A1000 . ACE1k gives the A1000 the most necessary upgrades: Memory (max 8M), Kickstart and (if an Agnus is put on it and the adapter is used to the internal Agnus) also 1M or 2M Chipram. A Zorro-style 100-pin slot can accommodate a Buddha or an ACA2000. The X-Surf-500 can also be plugged without ACA2000.

    -----


    1 or 2 MB chipram?? Yeah. SOOOO want that. Can you share any further about the ideas for the design? Sounds like it's early on. Is it going to be in the A1000 case or in a vertical case alongside? (With zorro style slot I guess it's external). Front-facing CF card slots? Comes with a case? rear-facing ethernet port?


    Sounds amazing!!!

    ACE1k ist still in the planning phase, and the "race with the crystal manufacturer" is lost already: The parts have arrived, but I had to move this project into 2019, as it's way too many other things that MUST be finished before Xmas 2018.


    There will be two Agnus-sockets: One for the 1MB version with 8372a-compatible pinout (there's a variant of the 8375 that has this pinout), and another with the 2MB-8375 pinout. Of course only one of the sockets can be used.


    The plan is to have a little adapter board inside the Amiga that replaces the DIP48-Agnus. A cable is routed to the outside through the 86-pin port opening, and the ACE1k board is attached to the side of the A1000. All signals for an external Agnus to work will come through the cable. The most tricky part is clock generation - note that other than the DIP48 adapter, there will be no other connections to the inside of the computer. The concept is geared towards making as little changes to the classic machine as possible.

    I was tinkering a little with a real 2MB Agnus on the A1000, but due to the limited quantity of chips available, I Have dropped this idea. It will probably be an Agnus-implementation in an FPGA - some time next year.

    Quote from rolle

    Maybe for other Amigas too?

    Not without making new PLCC84-insert-adapters. We've used the last ones for ACE2, and the company that makes them does not have stock any more. I'd have to make a new tooling.


    Quote from rolle

    Maybe without the 2MB limit?

    This would require patching Kickstart, and I have no idea how software reacts if it requests chip ram, and then gets an address in return that's beyond the usual $1f.ffff barrier. I know you can activate 4M of chip ram in an emulator, but how much software really makes use of it?

    Hello Jens, wonderful work, count me for purchasing one if you go to the final step...

    Quote from Jens

    I was tinkering a little with a real 2MB Agnus on the A1000, but due to the limited quantity of chips available, I Have dropped this idea. It will probably be an Agnus-implementation in an FPGA - some time next year.

    I think you would have a market for boards without the 8375 Agnus fitted as there are plenty of dead A500+ to get spare parts from. I love your other products btw!

    Anything that get us more chipmem in the 1000 is welcome, looking forward to seeing this!


    Agnus in FPGA is a smart idea - those 2mb chips are just too hard to find.

    Hello, any progress on this project?

    I’d really like to break the 512K chipmem barrier on my Amiga 1000.

    Thanks a lot for your reply. Nice to know it’s not forgotten, I really hope it materializes sooner or later.

    Moving higher on the prio list, even doing some key development work: Clock recovery/generation for the new Agnus chip has been verified. This means that installation can be done purely on the Agnus socket and the 86-pin expansion port, not requiring any clips/wires to other chips. This will be a major "plus" compared to any previous chip ram expansion that was made for the A1000. So far, any other unit required opening the clock cage on the A1000 main board, but my expansion won't need that.


    Note that this expansion will do more than just expanding chip ram. Still contemplating how I'll do mass-storage (either a slot for Buddha or CF card slots), and there should also be fastmem, flash and A1200 accelerator connectivity.

    Quote from Romel

    Is FPGA the final choice?

    No, the ACE1k (or ACA1k, not sure what the name will ultimately be) will only use "real chips". I have 1MB chip ram Agnus chips in stock that I'm planning to use, they have a 8375 designation but 1MB Chipram pinout like the 8372a. Only the "test" pin is a Vbb pin and requires an external cap, but the rest is identical.


    Logic for this will easily fit in a combination of discrete logic and CPLDs.