[Coco] MPI replacements?

[Little John (GIMEchip.com)]

Sorry about getting the name wrong :-)
So you did the MESS emulations? COOL
I just recently tried them and the beta machine would have been marvelous. I 
imagine they are rare?
Thanks for the info.
I'm just looking for projects to keep me designing and working away and the 
Dragon Beta really looks cool. Does one of the CPU's run just the video, or 
are they both dedicated to processing power? I imagine OS-9 would scream if 
that's the case.
I would love to find one, but I've probably got a better chance at loacting 
a dodo bird? :-)
Thanks - John
----- Original Message ----- 
From: "Phill Harvey-Smith" <afra at aurigae.demon.co.uk>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Sunday, July 11, 2010 2:43 AM
Subject: Re: [Coco] MPI replacements?


> On 11/07/2010 01:41, Little John (GIMEchip.com) wrote:
>> Mr. Smith,
>
> Err, that should be Harvey-Smith :)
>
>> I downloaded some Dragon Nitros9 images that had your
>> name attached to them, so I reckon you must be a Dragon kind of guy,
>> so I was wondering - I read a document regarding the DragonPlus
>> Upgrade Board. Do you know if schematics exist for this or at least a
>> good memory map for me to work from?
>
> I don't think schematics exist yet, however st some point in the future
> I will be atempting to repair one so I may be able to do some reverse
> engineering at that point. I believe that there is a technical document
> that contains a memory map on the dragon archive site :
>
> http://archive.worldofdragon.org/
>
> It's in Downloads -> manuals -> Compusense - DragonPlus.zip
>
>> I think this would be a great
>> project to clone and make available for both Dragons & CoCo 2's.
>
> Indeed, though it is only supported under OS-9 and Flex, though it
> strikes me that it should be possible to write a basic driver for it.
>
>> Also, is there a source of schematics of the Dragon Alpha & Beta?
>
> Alas no, though as I recently obtained an Alpha I am slowly tracing some
> of it out.
>
> The Alpha is basically a Dragon 64 with an additional PIA, an AY-3-8912
> for sound and disk control (drive select/motor), and a WD2797 disk
> controler. It has 1 or 2 built in 3.25" drives and a n additional 6850
> to handle the internal modem.
>
> However both machines are emulated in Mess, and where possible when
> writing the emulation I have tried to provide as much documentation in
> comments as possible.
>
>> These are two machines I would like to start an effort to clone into
>> an FPGA - I don't have the skills to complete such a thing, but I
>> would love to be part of a team that does :-)
>
> To clone the Alpha you don't really need an FPGA, just a donor machine
> (a Dragon 32 in my case), which I upgraded to 64K, built addon boards to
> hold the extra PIA & AY-3-8912, serial port and internal disk interface.
>
> Though if there was an existing CoCo 1/2 or Dragon 32/64 implementation
> it could be based on that.
>
> The beta however would be much more involved as it has two 6809s, and is
> a much more complex machine though again the current coco 3 in fpga
> could be used as a basis.
>
> Cheers.
>
> Phill.
>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


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