[Coco] MPI replacements?

[Little John (GIMEchip.com)]

Thanks to all for the input, you are definately helping to shape the future 
of this product and thanks to Jim and Panos for suggesting this project to 
me. This is one that I should be able to complete relatively quickly. The 
RAM upgrade on the other hand is giving me fits... I'll get it though, 
eventually.

Mr. 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 think this would be a great project to clone and make available 
for both Dragons & CoCo 2's. Also, is there a source of schematics of the 
Dragon Alpha & Beta? 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 :-)

Thanks All - John


----- Original Message ----- 
From: "Phill Harvey-Smith" <afra at aurigae.demon.co.uk>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Saturday, July 10, 2010 6:24 PM
Subject: Re: [Coco] MPI replacements?


> jdaggett at gate.net wrote:
>> The CPLD route is not all the panecia that it is cracked up to be.
>> ALmost all new CPLDs are no longer 5 volt tolerent. SOme are still
>> around that both input and output will drive 5 volt TTL logic. They
>> are expensive. Some of the newer less costly CPLDs need level
>> translation to properlydrive 5 V TTL loads as well as inputs.
>
> Whilst I would generally agree with that that expense is partly offset
> by the fact that once the board is laid out, if you get something wrong
> you can often fix it without having to throw the board away and start
> again, the logic can be re-jigged without having to resort to piggy
> backing chips, or dead cockroaching them :)
>
> Programable logic also often makes the board easier to route as some of
> the routing can happen inside the PLD etc.
>
> Cheers.
>
> Phill.
>
> -- 
> Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !
>
> "You can twist perceptions, but reality won't budge" -- Rush.
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.830 / Virus Database: 271.1.1/2993 - Release Date: 07/10/10 
01:36:00