[Coco] CoCo 3 MMU test for all

[John Guin]

I get 121.  My coco3 was not one one of the originals (I forget the year
number).

John

-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
Behalf Of Diego Barizo
Sent: Sunday, January 20, 2008 9:55 AM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] CoCo 3 MMU test for all

I just tried with a '86 GIME and 128 Kb, also getting 121.

Diego



Joel Ewy wrote:
> Roger Taylor wrote:
>   
>> Dudes and dudettes,
>>
>> There's a trick to creating super long LOADM'able programs on a CoCo 3
>> but it relies on every CoCo 3 giving the same results of the following
>> test:
>>
>> At the stock WIDTH 32 prompt, type:
>>
>> ?PEEK(65441)
>>
>> Won't you please type the above command on your real CoCo 3 only (not
>> an emulator), and post the results here?
>>
>> It *should* hopefully yield 57 which is an MMU block #, ofcourse.  If
>> it gives a reading of 11xxxxxx where the high two bits are set (or
>> either of the 2 high bits) then a separate special LOADMable program
>> would have to be created for that CoCo variation.  I could perhaps try
>> to LOADM a patch right into Disk BASIC that would ignore bad readbacks
>> while loading, but with all the types of DOSes out there, I doubt I
>> will take that route.  The upper 2 bit statuses also might depend on
>> the memory upgrade installed, etc.
>>
>>     
> I get 121 here on a CoCo 3 with a Tandy 512K upgrade.  I think that on a
> stock CoCo the memory is mapped into the upper range and mirrored
> throughout the lower addresses.  If you are using an emulator (which
> usually supports up to 2M) things may be different.
> 1.  My CoCo 3 service manual says those registers are "Write Only".  Do
> they mean that in the same sense as "No User Serviceable Parts Inside"?
:)
>
> 2.  I have a 1986 GIME chip laying around.  Should I pop that in and see
> if it's any different?
>
> JCE
>   
>> I have already created a test copy of Jeweled which LOADMs the 32k
>> backdrop graphics into MMU 48-51 before loading the program itself.
>>
>> This is nothing new, but it *is* 2008 and my way of thinking is not
>> like it was in 1985 or even 2005.  In a 512k CoCo 3 using the extended
>> LOADM trick, huge extraordinary-for-a-CoCo 3 games with HQ sound
>> effects and dithered graphics could be loaded in up to the size of a
>> floppy disk, ofcourse.  A 128k-size .bin file containing the entire
>> game contents?  I'll soon see.
>>
>>
>>
>>
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>>
>>     
>
>
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>   

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