Re: Disabling memory refresh in UltiMax mode Re: 6510 handling of $00 and $01 registers

From: Gerrit Heitsch <>
Date: Sat, 10 Dec 2011 21:14:03 +0100
Message-ID: <>
On 12/10/2011 08:51 PM, Segher Boessenkool wrote:
>> When testing a C64, I use the type check program mentioned above plus
>> a RAM test and the 'Edge of Disgrace' demo. The latter has a few
>> 'plasma' effects and on those you notice that they were written for a
>> 9-luma VIC. On the 6569R1 they look less smooth.
> You could just switch the monitor to greyscale :-P

That takes out the color effects that are part of the demo.

I don't plan on using the 6569R1 regularly. But it's nice to have a 
really old C64 (includes real PLA and -02 Kernal ROM) handy when 
checking software compatibility. The RAM test I use crashes on the -02 
ROM, plug in a -03 ROM and it works.

Back then the CIAs were also labled 6526R4. MOS dropped the 'R4' later. 
Gives you an idea how long it took to get those working. :)

>> To bad no one has yet been able to find a software trick to
>> distinguish between the 6510 and the 8500. :)
> They didn't? I thought you could do the timing thing with the high
> port pins? Very unstable of course...

Yes, there seems to be some kind of overlap so that there is no way to 
be 100% sure whether you have a 6510 or a 8500. All you seem to be able 
to do is get an approximation of the die temperature if you take a 
measurement at power on and re-measure later.


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Received on 2011-12-10 21:00:21

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