RE: 6530 replacement

From: Martin Hoffmann-Vetter <>
Date: Fri, 11 Oct 2013 02:44:12 +0200
Message-ID: <001801cec61b$01d7f570$>
Hello Gerrit,

> The large
> drives use two 6502 running on the same clock speed, but 180 degrees
> out of phase (kind of like the 6510 and VIC in a C64). They use the
> same data bus while the address bus is seperate and only a certain
> part of the RAM can be seen by both CPUs.
> To make that work, all chips used on that construct must have PHI2 of
> the CPU they are working with as part of their enable signal.
> Otherwise it would happen that 2 chips are active at the same time
> and fight over the data bus.
> It's a simple way to make 2 CPUs work together without getting in the
> way of each other while still being able to share data.

Yes, it's true. I forgot this argument at the night i wrote the answer to ruud. But i think, there was more than this error. The address logic was very strange.



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Received on 2013-10-11 01:00:13

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