A little update on the minimig core

Quite some time has passed from the last minimig release, so I thought I’d write a short update on what’s going on.

The work on minimig-mist aga v1.2 is progressing, albeit slowly, since I don’t have much free time right now. Here are some of the fixes already implemented and in testing:

  • video dithering (both random and spatial) have been fixed – the dithering didn’t work at all before
  • scanlines can now be enabled in non-scandoubled mode
  • CPU cache control with the CACR register implemented
  • fixed reset problems and fast RAM disappearing
  • kickstart ROM is also uploaded to kickstart mirror position (E0)

Two chipset bugs were also discovered and fixed. The first one was a sprite colortable lookup problem, which was sometimes apparent as a missing sprite line, or wrong sprite color (see here for an example: https://www.youtube.com/watch?v=HD5znZGIvP4). This one was very hard to track down – it required single stepping through the frame with WinUAE debugger, but very easy to fix. The other one was a blitter line mode problem (see http://www.a1k.org/forum/showpost.php?p=904090&postcount=54), that was just the opposite – very easy to track down, and harder to fix.

Till Harbaum has made some updates to the CPU bitfield instructions, that fixes *a lot* of games and demos. There are still some stability problems with the CPU, I’m working on ways to fix that.

Besides that, a few other changes are still planned for the 1.2 release:

  • programmable display modes (Productivity, DblPAL/DblNTSC, Euro36/Euro72)
  • HELP button fix
  • ethernet support (hopefully!)

I think I still need a week or two before the release will be ready. I’ll keep you updated!

minimig AGA v1.1 for the MiST board released

There is a new release of minimig-AGA for the MiST board available, grab your fresh copy on the minimig-mist page!

Here are the updates made in this release:

  • fixed mouse issues (fixes games Like Ishar 1, 2, 3, Robinson’s Requiem, and many cracktros)
  • fixed keyboard issues (fixes game Walker and probably many others)
  • changes to FPGA clock handling, hopefully this will make a more stable minimig core
  • entering the OSD menu using UP+DOWN buttons on a DB-9 connected joystick has been disabled
  • 1MB kickstart ROM support added (enables you to run AROS ROM or your custom kickstart ROM)
  • firmware now again supports using 256kB kickstart ROMs
  • firmware now again supports using Cloanto AmigaForever encrypted kickstart ROMs


Amiga 30 event

amiga30.eu event in Amsterdam

Last weekend the Amiga: 30 years event took place in Amsterdam.

It was great seeing and hearing some of the original Amiga engineers and other people involved in the Amiga ecosystem sharing their stories, and I can honestly say that the dedication and love these guys put into the Amiga can still be felt today. Thanks guys for making Amiga what it was (and is!).

There was a tent outside with lots of Amiga hardware on display, some nextgen systems, plus lots of rare-ish Amiga models that I never saw in person, like the A4000T, the CDTV, the Walker prototype, the A1000, etc. There was also one original minimig on display, unfortunately no MiST boards (I wanted to take my MiST board with me, but I missed the exhibitor tickets – they were gone like hot cakes! Maybe at the next meeting in ten years 😉 ).

Plus, I got to meet Joe Pillow!

Thanks to the organizers for making this event possible, I had a great time, hopefully there will be another event like this for the 40th anniversary of the Amiga!

amiga30-2107 amiga30-2108 amiga30-2110 amiga30-2112 amiga30-2114 amiga30-2119 amiga30-2122 amiga30-2045 amiga30-2047 amiga30-2050 amiga30-2053 amiga30-2054 amiga30-2055 amiga30-2056 amiga30-2057 amiga30-2060 amiga30-2065 amiga30-2067 amiga30-2070 amiga30-2072 amiga30-2074 amiga30-2076 amiga30-2080 amiga30-2082 amiga30-2089 amiga30-2090 amiga30-2095 amiga30-2098

Here are some of the videos of the event I found on Youtube:

I finally know how the hand holding the floppy came about 🙂

minimig AGA v1.0 for the MiST board released

There is a new release of minimig-AGA for the MiST board available, grab your fresh copy on the minimig-mist page!

It certainly took a while, but I think I can safely say that the AGA chipset is implemented correctly and in full now, but of course with lots of corner cases not handled properly. There are still quite some problems on the CPU side though, those will hopefully be fixed in time.

There are some issues worth mentioning – one is that the turbo kickstart is not working properly in all cases, so for now this feature is experimental, and it is recommended to only enable it if you don’t have any problems with it. The other issue is that currently, the HRTmon monitor doesn’t work OK when the VBR is moved to fastRAM, so either don’t use utilities like VBRMove, or don’t use HRTmon.

In the zip file, there is a firmware.upg added. There is no need to update the firmware of the MiST board if your firmware is newer than 16th of June 2015. If it is older, it is recommended to update your firmware.

Here are the updates made in this release:

  • fixed AGA color table issues
  • fixed erroneous detection of HAM, HAM8 & EHB modes in AGA
  • fixed AGA BPLXOR implementation
  • implemented AGA bitplane scandoubling
  • implemented AGA sprite scandoubling & SSCAN2 SH10 coincidence detection
  • implemented proper AGA bitplane scroller with quarter pixel scrolling precision
  • fixed AGA BPLCON4 values delay
  • playfield CLUT offsets fixed
  • ECS sprite attach enabled for both odd and even attach bit
  • turbo options for chipRAM & kickstart
  • new 8kB two-way, write-through, look-through CPU cache with separate instruction & data caches
  • CPU PACK & UNPK instruction fixes by Till Harbaum
  • updated very fast CPU by Alastair M. Robinson (in the newcpu build)
  • CIA TOD bug fixed
  • HRTmon with custom registers mirror
  • chipset config applied only on reset
  • config display added on boot screen



a video showing the speed of the new CPU on this release: