Re: 6526A synchronous serial behavior?

From: Groepaz <>
Date: Thu, 22 Sep 2011 22:35:52 +0200
Message-Id: <>
On Thursday 22 September 2011, you wrote:

> if it is different behavior from drive to drive then this let's me think
> on different CIA revisions. 6526 vs. 6526A vs. 8520, you know even VICE
> does support two different 6526 types, the "old" and the "new" one which
> have some off-by-one clock cycle differences.

and that said, NEVER trust whats written on the chip package. i have seen all 
kinds of combinations by now, they probably just used what whats there and 
slapped a label on it (its commodore afterall =P) - the manufacturing date 
seems to be more relevant than A or not or 6526 vs 8520 :) (eg i have one 
"flat" c64 here, with one 6526A and one 6526 on it, which both exhibit "new" 

so if you want to know what kind of cia you really have, run a program that 
tests the interrupt delay ( for example )

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Received on 2011-09-22 21:00:27

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