[Coco] 32K carts?
joef6809 at gmail.com
Tue Oct 23 10:48:24 EDT 2007
That is interesting. I wonder now if all the 32K images floating around the
net are backward like that.
When I was working on getting these running I jut assumed the images were
correct and my MMU emulation was off. now I'm not sure. I've got a real
Rampage! cart. Does anyone know if the chip inside it is pin compatible with
a 27256. I'll try to pry it out and read it on an external Eprom programmer.
----- Original Message -----
From: "Mark McDougall" <msmcdoug at iinet.net.au>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Tuesday, October 23, 2007 5:37 AM
Subject: Re: [Coco] 32K carts?
> Joe wrote:
>> When you switch to 32K External it gets wierd.
>> $C001 to Whatever is mapped to the first 16K of the ROM and $8000 to
>> $C000 maps to the last 16K of the ROM. This makes sense as any code
>> running from rom say at $C??? would need to turn on 32K External mode,
>> but when that happens if it was a liner map the code that was executing
>> would "jump up" 16K.
> Thanks Joe - that's done the trick. I had to swap the upper and lower 16KB
> in Arkanoid and it runs now! Presumably Rampage has the same issue.
> I need to order a couple of more passives now to be able to test the flash
> option and the "Flash2" cart.
> For those few interested, I'll do some pricing very soon. I've been
> ultra-busy the last few weeks and have only been able to devote the odd
> minute here-or-there to this project...
> | Mark McDougall | "Electrical Engineers do it
> | <http://members.iinet.net.au/~msmcdoug> | with less resistance!"
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> Coco at maltedmedia.com
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