Another Minimig release!

2020-07-12

If it’s seemed quiet here lately, that’s because I’ve been hard at work improving the Turbo Chameleon 64 ports of the Minimig core.

The two main features added since the last release are an experimential implementation of the Akiko Chunky-to-Planar converter which can be used by a handful of games to increase video performance, and an experimental P96 retargetable graphics driver.

The latter allows system-friendly applications to display higher resolutions and bit depths and with better performance than the Amiga’s own chipset allows. Both 8-bit (256 colour) and 15-bit (hi-colour) modes are supported, but since memory bandwidth is limited, 15-bit is only available in lower resolutions. The highest resolution I’ve had running in 8-bit mode is 1440 x 900, but at that resolution it uses so much RAM bandwidth that it’s too slow to be usable.

A 256-colour 800×600 Workbench is a very pleasant experience, however, and Mac emultion with Shapeshifter in 15-bit colour is also much nicer than can be achieved with AGA

To complement these new features there’s also a new Utilities disk which contains not just the mouse wheel driver (as well as FreeWheel), but also a keymap editor, along with a ready-made keymap for UK PS/2 keyboards, lha, the fat95 filesystem, a mountfile which can be used to mount the SD card’s FAT partition from within the Amiga, and of course the RTG driver.

Internally, there have been some changes to the OSD / Menu / Host code, which now has better error handling and reporting. The SDRAM controller now uses 8-word bursts rather than 4-word bursts. The extra bandwidth from this change is what makes RTG modes possible.

Finally, I’ve fixed a long-standing bug regarding ADF writes which caused disk corruption when copying files to an ADF from Workbench. The bug was a very subtle problem which only showed up when a write to one track was immediately followed by a read from the next track. The read would return bad data. The bug was a one-line fix, which took a big chunk of the weekend to find!

There is still a problem with copying to ADFs from within Workbench 3.1.4, however, which is unrelated. Copies seem to grind to a standstill and wedge the host CPU so that the menu no longer works. Copying from the RAM disk works, however, as a workaround.

The core can be downloaded, as always, from the Turbo Chameleon 64 menu at the top right.

I must say a big thank you to everyone who’s supported this project financially – either at https://www.paypal.me/robinsonb5 or via Patreon at https://www.patreon.com/coresforchameleon If you’d like to show your appreciation then donations are always welcome, and while I don’t paywall any files or releases, the core does have a “Supporters” screen within the menu, where I will include the names of anyone who donates at least £20 or who supports me on Patreon at the Core Supporters tier.

4 thoughts on “Another Minimig release!

  1. Hello,

    I’ve been trying the new AGA/TC64 core. Overall it seems to work but I’ve noticed a problem with the expermiental p96 drivers. Is there something I need to do to enable them? I tried installing/copying the needed files as per the instructions but got this error message at boot;

    Picasso96: Could not create graphics board context for ‘Minimig’,
    please check your Picasso96 installation.

    I did install picasso96 (the file came from aminet), renamed the monitor file and changed the boardtype and copied the minimig.card file into libs:picasso96 .

    Is the board tooltype case sensitive at all?

    ljones

    • I don’t think it’s case sensitive – but it can’t hurt to try. The only thing that springs to mind is to make sure you have 24-meg of Fast RAM enabled – the first thing the driver does is allocate a 4 meg chunk of fast RAM.
      If that still doesn’t work, can you move the monitor from devs:monitors to sys:storage/monitors then reboot, run snoopdos and double-click the monitor’s icon in storage/monitors – the snoopdos log might give you some clues as to what’s failing.

      • Looks like it was because I didn’t have mine set to 24MB. Didn’t realise this was a requirement as I was thinking it would behave a little like UAE/EUAE does. Ok, no problem — I have it working now set to 24MB!

        ljones

        • Glad you got it working – I hadn’t thought of the 24-meg thing, so it’s not documented yet – I will fix that. I will also adjust it so that it falls back to a smaller videocard memory if it can’t get 4 meg in one lump.

Leave a Reply to AMR Cancel reply

Your email address will not be published.