Re: Commodore "Most Wanted" List

From: Gerrit Heitsch <>
Date: Fri, 04 May 2012 18:29:05 +0200
Message-ID: <>
On 05/04/2012 07:22 AM, Baltissen, GJPAA (Ruud) wrote:

>> Not every 1772 can be overclocked
> You mean running at 4 MHz, why would that be needed? Or am I missing
> something?

No, the WD1772 needs to run at 8 MHz to read double density. You have 
overclock it to 16MHz to read high density unless you revert to reducing 
the rpms. Not all 1772 were able to take that abuse. Some just didn't 
work, some failed after a while.

And the still unanswered question is, how may cycles of a 6502 do you 
need to read one Byte from a WD1772 including verification that it's a 
valid one.

I have the nagging suspicion that the data seperator as used in a 1541 
with using the SO pin is as fast as it gets and all other solutions need 
extra cycles and that's why a 1581 runs at 2 MHz already even though the 
data rate is still DD.


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Received on 2012-05-04 17:00:09

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