[Coco] Could MESS CD-i emulation be hacked to MM/1?

[Joel Ewy]

KARL SEFCIK wrote:
> Aaron and others,
>   I don't know if this will get through, but if you remember, CDI ran off the 68070 chip, which had different architecture than the straight-out 68000 family. Back in it's time, a separate appliance was 'in vogue', before cd players were slots in PC's. So like previous attempts to emulate CDI, it may need a daughter processor. But CDI still is the first attempt at full motion digital video, and yes, I still have some CDI movies that I have not seen or even opened yet.Karl
>
>   
Hi Karl,

The 68070, even though it has a number that appears to make it an 
advanced member of the 68K family (such as the 68020 - 68060) actually 
has a basic 68000-compatible core with the addition of some extra 
hardware, such as a DMA controller, a simple MMU, and so on.  More to 
the point, the MM/1 and the TC-70 computers also used the 68070, 
specifically chosen with the idea of making it similar to the CD-i 
platform.  But what matters more is that the MM/1 (and I think also the 
TC-70) also used a Signetics 66470 Video / System Controller (VSC), 
which was also developed for the CD-i.  Because the MM/1 and TC-70 
shared so much hardware with CD-i players, a hardware-level CD-i 
emulator gets pretty close to being able to emulate those old OS-9 
computers.

JCE

> --- On Mon, 11/23/09, Aaron Wolfe <aawolfe at gmail.com> wrote:
>
> From: Aaron Wolfe <aawolfe at gmail.com>
> Subject: Re: [Coco] Could MESS CD-i emulation be hacked to MM/1?
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Date: Monday, November 23, 2009, 10:49 AM
>
> wow, I don't know if I can be of much help but this would be really
> cool to see!  Always dreamed of playing with the MM/1.
> -Aaron
>
>
> On Mon, Nov 23, 2009 at 11:44 AM, Joel Ewy <jcewy at swbell.net> wrote:
>   
>> Apparently the latest version of MESS has "reasonable CD-i emulation":
>>  http://cdii.blogspot.com/2009/11/latest-mess-includes-reasonable-cd-i.html
>>
>> It appears that there is now enough CD-i hardware emulation to run Lemmings
>> and some other games.  This means that the Video / System Controller
>> hardware is present in at least some rudimentary form, which, along with the
>> CPU and OS-9 operating system, is what the MM/1 shared with CD-i.
>>
>> Though it appears to be in an early stage, this is certainly an interesting
>> development.  It would be very nice to be able to run MM/1 / TC-70 software
>> in emulation.  In fact, an OS-9/68K emulation machine based on the CD-i
>> would have much better graphical capability than the real computers did.
>>
>> It looks like MESS may already have support for:
>> 68901 MFP (from the Atari ST)
>> 68681 DUART
>> WD33C93 SCSI Controller (From Amiga 3000)
>> NEC765 FDC (Is this register compatible with the WD37C65 used in the MM/1?)
>>
>> The only major chips I see that the MM/1 has that don't appear already to be
>> emulated in MESS are the 68230 (which is essentially a glorified PIA with
>> timer) and the AD7569 ADC/DAC chips.  The 7569 certainly isn't required to
>> boot OS-9, and I think the 68230 is just used for parallel ports, though I'd
>> have to look at schematics again to be sure.
>>
>> It looks as if it would almost be a matter of gluing together some blocks
>> that are already present in the MESS codebase to get something that would
>> boot OS-9 from an MM/1 disk image.  I haven't really looked at the MESS
>> code, and my C is fairly well oxidized K&R, but I do have a working MM/1 and
>> plenty of MM/1 technical information.  I know Tim Lindner has been involved
>> with the MESS CoCo port.  Surely there are enough capable and motivated
>> people on this list to make a go of it...
>>
>> JCE
>>
>>
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