A512 Question

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Don't Panic. Please wash hands.
  • I have an Amiga 500 rev 8A.1

    The mainboard is the same of A500+ (the A500+ logo is marked on it) with full ECS chipset, but with only 0.5MB of Chip ram and no RTC clock mounted.

    With 2 A512 expansion cards connetcetd together + an RTC clock module, I should have 1.5 chip ram and a RTC clock on my amiga.


    To have 2mb of chip I founded some tutorials to modify the mainbord to add the last 0.5mb, but I don't want modify my amiga.

    All changes I want to do must to be reversible to mantain complete originality of my machine.


    My question is: can i use 3 A512 memory expansions connected together + RTC clock module on the first exp. to have 0.5 mb chip on the mainboard + 1.5 mb on the trapdoor, or the maximum chip ram avaible is 1mb from the mainboard + 1mb from the trapdoor?


    Thank you

    A500 rev 8A.1 - 68010 0.5mb chip ram - dual KS 1.3/3.1 - 0.5mb fast ram trapdoor - GVP Impact II (105mb Quantum hdd + 8mb fast ram)

  • My question is: can i use 3 A512 memory expansions connected together

    No, that won't work.


    However, I have yet another trapdoor mem expansion called "A2048" in the works that will give you the full 2MB of chip ram with your Rev.8 A500, where only very slight modifications to the main board are required. Not the "large mod" with added chips, but a few tiny things like jumper wires and cutting connections: Very easy to add, and very easy to revert as well. The expansion will go on sale either this coming week, or early January. I just need to write the instructions and make a shop page...

  • No, that won't work.


    However, I have yet another trapdoor mem expansion called "A2048" in the works that will give you the full 2MB of chip ram with your Rev.8 A500, where only very slight modifications to the main board are required. Not the "large mod" with added chips, but a few tiny things like jumper wires and cutting connections: Very easy to add, and very easy to revert as well. The expansion will go on sale either this coming week, or early January. I just need to write the instructions and make a shop page...

    Ok. Thanks. I think anyway to buy 2 A512 and a RTC clock (1.5Mb chip ram is enough for me), but I will wait until I see A2048 specifications.

    A2048 have an RTC clock module or an option for it?


    One more question.

    In the description of A512 I read that 3rd party cards can by attached to that.

    The question is: if I attach my existing expansion to 1 (one) A512 with the jumper on the A500+ position, the system will see 1mb chip (0.5 on the mainboard + 05 on the A512) + 0.5 fast from my exp, or because is in the chain with the A512, the system see all the ram in the trapdoor as chip ram for a total of a 1.5mb chip ram?

    The expansion (see image below) is a non original, buyed with the amiga in the '93.


    If I can save some money from the ram, maybe I can buy an Indivision ECS v2 too. :):)


    Thank you for your support.


    A500 rev 8A.1 - 68010 0.5mb chip ram - dual KS 1.3/3.1 - 0.5mb fast ram trapdoor - GVP Impact II (105mb Quantum hdd + 8mb fast ram)

    Edited once, last by sharmak ().

  • Ok. Thanks. I think anyway to buy 2 A512 and a RTC clock (1.5Mb chip ram is enough for me)

    Even 1.5mb of chip ram will only work with your Rev.8 board if it has been modified with the added chips. The A512 will not make you happy here :-)

    A2048 have an RTC clock module or an option for it?

    It has an option for an RTC module.


    In the description of A512 I read that 3rd party cards can by attached to that.

    The question is: if I attach my existing expansion to 1 (one) A512 with the jumper on the A500+ position, the system will see 1mb chip (0.5 on the mainboard + 05 on the A512) + 0.5 fast from my exp, or because is in the chain with the A512, the system see all the ram in the trapdoor as chip ram for a total of a 1.5mb chip ram?

    Your Rev.8 Amiga will only be able to use 0.5mb, no matter what type of expansion you use. Only if you upgrade it to a full A500+ with the added chips, you'll have more chip ram. And in that case, yes, you can use one A512 and one standard 0.5M trapdoor expansion to have a 1MByte chip ram addition. However, I'm pretty sure that you will also need the full 1MByte of chip ram on the main board, otherwise you won't see the trapdoor expansions.


    So no matter how you twist it, you'll always have to do some soldering on this board. The only possibility to get around soldering in your case is to use the ACA500plus: It will turn your existing trapdoor expansion into chip ram.

  • I've AGNUS 8375 and DENISE 8373R4PD originally mounted on my board (ECS chipset of the A500+).

    AGNUS 8375 should be address 2mb of chip ram, so 1 mb from 2 A512 in the trapdoor is no accepted by the system?

    A500 rev 8A.1 - 68010 0.5mb chip ram - dual KS 1.3/3.1 - 0.5mb fast ram trapdoor - GVP Impact II (105mb Quantum hdd + 8mb fast ram)

  • The Agnus can do it, but it needs to see the correct CPU address lines for that. In normal configuration, it sees A23 on it's A19 input, which lets it map memory to $c0.0000. The ACA500plus re-maps $c0.0000 memory to $08.0000 with a simple memory mapper, but if you don't have an ACA500plus, you'll have to change a solder-jumper on the main board. And if you're willing to do that anyway, you might as well change two more things on the board and make yourself the cheapest 2MB chip ram expansion that's commercially available, using the A2048 :-)

  • Any news about A2048 release?

    Thank you.

    A500 rev 8A.1 - 68010 0.5mb chip ram - dual KS 1.3/3.1 - 0.5mb fast ram trapdoor - GVP Impact II (105mb Quantum hdd + 8mb fast ram)

  • Not yet - the combination of "way too much administrative work in January" and being short-handed due to Corona distancing rules doesn't make things easier. I hope we can get to testing them next week, which in turn will push me to making the online documentation.

  • Will the A2048 give me 2MB or chip RAM in an Amiga 500 v5 or v6? what about if I also have the ACA500Plus? is there any way I can get more than 1MB chip RAM in any of those Amigas?

  • Will the A2048 give me 2MB or chip RAM in an Amiga 500 v5 or v6?

    No, it's not made for that board revision - at least not without an additional adapter under the Gary-chip, which I don't intend to make.


    what about if I also have the ACA500Plus?

    Same answer as above.


    is there any way I can get more than 1MB chip RAM in any of those Amigas?

    Yes - the product name is "ACE2b".

  • At first I thought I wouldn't need the 2Mb chip ram, but a few weeks ago I ordered and installed the ACE2b. Because I mainly work in HighGFX with the Indi ECS V2, the extra ram is more than welcome. Great product.

    A1200 Rev2B | SanDisk CF64GB HDD | Blizzard 1230 IV 64MB FPU 68882/50 | Indivision AGA MK3 | CA-PSU | Eizo S1933 | Bose Companion 2 series III

    A500 Rev6A | SanDisk CF16GB HDD | ACA500Plus V2 / ACA1221lc | Indivision ECS V2 | ACE2b | CA-PSU | Eizo S1933 | Bose Companion 2 series III