Minimig AGA update


I’ve just released an updated version of the MinimigAGA core for all three of my current target platforms – TC64 version 1, TC64 version 2, and MiST.

The core doesn’t have 100% feature parity between the three platforms, since the MiST has an onboard microcontroller to handle input and storage, while the Chameleon doesn’t. Having to implement an equivalent microcontroller in the FPGA makes some things harder – but other things easier.

For this reason, this time around the TC64 ports have a feature not yet available on MiST – experimental floppy drive sounds. To enable this, simply copy the drivesnd.bin file onto the SD card. If you don’t like it, just delete the file again – there isn’t (yet) a way to turn it on and off from the menus.

Other changes this time include the addition of a very basic LED Audio filter implementation – not accurate, but just good enough to make the going-through-tunnels sound effect in Lotus II work, and Slingshot on Atari-Forum has put some hard work into debugging the CPU core, and found an issue with stack frames which was preventing certain Graftgold games from working in ‘020 mode. His fixes to the CPU are included.

I’ve also made some timing tweaks on all three platforms so that all of them build with clean timing reports.

Turbo Chameleon 64 users can find the latest version of the core here

MiST users can find the latest version of the Minimig core at the official MiST binaries repository.

15 thoughts on “Minimig AGA update

  1. Hello,

    it seems that the MinimigAGA cores (I tested MinimigAGA_TC64V1_20200921 and MinimigAGA_TC64V1_20200823) are unstable when using the Chameleon V1 in the docking station and accessing an ADF-file. Tested multiple configurations (68000, 68020, Kickstart 1.3, Kickstart 3.1, no fast ram, max fast ram).

    Problem: When accessing df0: in docking station mode random crashes (reboots) can be observed.

    When using the Chameleon V1 in standalone mode, floppy access seems to be stable in docking station mode.

    There is a minor index glitch in the menu. When returning from the About or Supporters section back to the superior menu level, the highligted selection is only visible when you navigate up or down with the arrow keys. When returning from the Reboot section, Reset is highlighted.

    Great work! Do you plan to include a “Return to Chameleon” menu point like in the non-AGA-core (Minimig_TC64V1_2019-11-16)?

    Best wishes,


    • Thanks for the bug report – I’ll see if I can reproduce it. I will attempt to add the return-to-chameleon option at some stage – however it wasn’t reliable on the ECS core, so I clearly need to put more effort into making it work properly if I do add it again.

    • I wrote nonsense:

      When using the Chameleon V1 in standalone mode, floppy access seems to be stable (delete “in docking station mode”).


      • It’s OK, I understood you. I think I’ve found the problem – it seems to be related to the reset pin from the Amiga keyboard header. I’ll release an updated core soon, so you can see if ignoring this signal fixes the problem.

        • Hi,

          just tested MinimigAGA_TC64V1_20201023. Floppy access in docking station mode now works without problems.

          There are still some minor glitches in the menu.

          * When entering the “About” section, the “back” selection is not highlighted. When pressing cursor up, “back” gets highlighted and the text scroller restarts.

          * Same behaviour in the “Supporters” section.

          Can you give me a hint how to activate HRTMon. I activated the corresponding menu point and copied hrtmon.rom to the root directory of the SD-card. Didn’t work.

          Best wishes,


  2. Hello,

    just tested MinimigAGA_TC64V1_20201205 and found three glitches:

    (1) When checking drive speed with sysinfo (V3.24) on hard disk images (RDB), the following error requester shows:

    *** FATAL ERROR ***
    SD Card
    CMD18 – invalid response

    When pressing the scsi button in the drives section of sysinfo, pressing exit and then selecting another partiton, the following error requester shows:

    *** FATAL ERROR ***
    CD Card
    CMD18 – no data token

    When working with a filesystem hard disk (no RDB) these errors don’t show. Tested on several SD-Cards (Sandisk, Transcend, …). When you select reboot in these requesters the system hangs.

    (2) When selecting Reboot in the menu, the screen reads:

    Minimig AGA BETA version 2020-12-05 …

    Overriding screenmode.

    Afterwards drivesound (floppy and HD) is muted.

    When starting the 2020-12-05 core the first time, no “BETA” and no “Overriding screenmode” is printed.

    Also pressing the third (right) button on the chameleon leads to the “BETA” and “Overriding screenmode” printing. Drivesound works after this reboot.

    (3) When pressing the third (right) chameleon button the reboot fails sometimes and the system hangs (you have to powercycle to go on).



  3. I’m trying to port this Minimig AGA core to a Xilinx Artix 7 FPGA.
    Where can I best ask questions regarding issues I run into?

    • I’ve just sent you an email, so you can get hold of me that way if you like – but also there’s’s MiST subforum which I think is the nearest thing to a “home” forum we have now. The old forum at is now long gone, sadly.

  4. When compiling your kernel for Cyclone V 5CEFA2F23, incomprehensible errors pop up. both with syntax and others. could you try to compile for it?

    • Porting it to a new FPGA isn’t a trivial task – but I did try to compile it once for the CycloneV-based UnAmiga variant (I think that’s the same chip you’re trying to use?), and it wouldn’t fit in the FPGA. What exactly are you seeing, error-wise?

    • I probably won’t be able to help you make it fit in that board – the version you linked to is only vaguely related to the current MiST core: they share a very distant ancestor. The DE1 core was forked to make a version for DE0-nano, and the control CPU was changed to mor1kx (a different OpenRISC from the one used for DE1), then someone else backported the AGA stuff. Neuro would be the best person to ask how to build the core for the QMTech board. I did try, briefly, to make the newer MiST core fit – but had no success.

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