hey,
Uhm, lets not get to technical here, ok? ;)
Anyway, I don't have a Memory Mapper either.
I just "started" my MSX hobby, again.
So any help would be apreciated.....
Thanks,
Hans
-----Original Message-----
From: Marco Antonio Simon dal Poz <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: dinsdag 2 maart 1999 14:31
Subject: Re: Cracked ROM in 24k portions
>On Tue, 2 Mar 1999, Hans Korving wrote:
>
>> Is it possible to make the MegaRAM yourself using all new parts?
>> Or do you need old cartridges?
>> Anybody has any schematics?
>
>It's perfectly possible. You can use the same memory IC's used in Memory
>Mapper. The difference is only the block switching circuit.
>
>I don't know anybody who has the schematics, but it's not very difficult
>to create one. The special feature is the port 8Eh, that selects between
>BLOCK SELECT mode and WRITE ENABLE mode.
>
>In a Megaram, when you execute a "IN A,(8Eh)", you put Megaram in WRITE
>ENABLE MODE. The accumulator receives garbage. When you execute a
>"OUT (8Eh),A", you put Megaram in BLOCK SELECT MODE (exactly as a Megarom
>cartridge), whatever the contents in the accumulator.
>
>In Brazil, we have Megaram models of 256kb, 512kb and 768kb.
>
>Greetins from Brazil!
>
>-----------------------------------------------------------------
>Marco Antonio Simon Dal Poz http://www.lsi.usp.br/~mdalpoz
>[EMAIL PROTECTED] "Apple" (c) Copyright 1767, Sir Isaac Newton
>
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