[Coco] Un-upgraded 3124 Multipak/Coco3 Question

[Mike Pepe]

Mark,

I hate to disagree with you after you disagreed with my agreeing with 
you... ;)

The 244's buffer the data bus from the RAM banks.

The CPU is buffered from the data bus via a 245...

...but the general data bus goes right out the cart port. The GIME and 
MPI would indeed be duking it out if there's an addressing conflict.

-Mike

Mark Marlette wrote:
> Mike,
> 
> I hate to disagree with you after you agreed with me but.....
> 
> That is not exactly true. The GIME is buffered by the 244's. The MPI is 
> buffered by the 245, so those two would fight for the data bus.
> 
> The GIME wouldn't be damaged the buffers possibly would be.
> 
> Mark
> Cloud-9
> http://wwww.cloud9tech.com
> 
> Quoting Mike Pepe <lamune at doki-doki.net>:
> 
>> I second that. Essentially the MPI and the GIME chip will respond to
>> the same addresses. Reading is probably the worse of the two in terms
>> of potential damage, since the GIME and MPI will be driving the data
>> bus at the same time. It could potentially kill the GIME. Not likely,
>> but it is possible.
>>
>> -Mike
>>
>> Mark Marlette wrote:
>>> David,
>>>
>>> The MPI and CoCo3's memory map conflict. Depending on what the  
>>> program is accessing for addresses, depends on the damage or  
>>> possible damage.
>>>
>>> It is a real issue and should be a concern to non upgraded CoCo3 MPI 
>>> owners.
>>>
>>> Mark
>>>
>>> Quoting David Grimmel <navydave1 at hotmail.com>:
>>>
>>>> I know I need to upgrade my white 3124 multi-pak to be 100% compatible
>>>> with my Coco 3, but havent gotten around to it yet. While reading a
>>>> Marty Goodman Q&A in the July 88 iss of Rainbow, he says, "even if your
>>>> Coco 3 {appears} to work fine with your Multi-Pak, the upgrade is
>>>> required. The upgrade may prevent slow, subtle damage to your Coco 3".
>>>> I knew that using it un-upgraded my cause small glitches and software
>>>> problems, but I didnt think it would cause any physical permanent
>>>> damage. What damage is the good DR. referring to? Have I already
>>>> damaged my Coco 3 by using it with an un-upgraded 3124 multi-pak?
>>>>
>>>> Dave
>>>>
>>>>
>>>>
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>>>
>>>
>>>
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> 
> 
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