Re: 6567 revisions (was Re: 264/TED/Plus4 Story)

From: Gerrit Heitsch <>
Date: Thu, 25 Aug 2011 19:06:53 +0200
Message-ID: <>
On 08/25/2011 06:54 PM, Segher Boessenkool wrote:
>> Hm, I own a 6569R3, some 6569R5 and some 8565R2. I don't notice any
>> difference in picture quality between the 6569-Revisions, the 8565R2
>> seems to provide a slighty brighter picture. It also has the
>> 'grey-dots-bug'. If you write to the background or border color
>> register (even if this doesn't change the contents) you get a grey dot
>> on the screen at the moment the register is written to. The intro for
>> Giana Sisters does show that quite nicely. Looks like a kind of 'snow
>> effect' if done right. This doesn't happen on a 6569. On some
>> 8565-VICs it goes away once the chip warms up.
>> The bug is also present with TED and the VIC used in the C128. It
>> seems as if it got introduced with the switch to HMOS.
> Are you sure this depends on the chip, and not on the board? The grey
> dots are caused because #CS is active before the data lines are. The
> dots go away if you add a cap to the #CS line.

Well, TED doesn't have a _CS line, it does all decoding internally... Of 
course when it comes to the 8565, it could be that the 64pin PLA is a 
lot faster than the 28pin from the old boards and that's the cause. 
Can't easily use a 6569 in a new board though since the chip needs +12V.


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Received on 2011-08-25 18:00:23

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