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

From: Gerrit Heitsch <>
Date: Sun, 11 Dec 2011 21:09:17 +0100
Message-ID: <>
On 12/11/2011 08:52 PM, Segher Boessenkool wrote:
>> The one I have has the datecode 4586. There are other 6526A from the
>> end of 1986 that are likely the HMOS-Version, they also show the timer
>> 'bug' and the test program lists them as '6526A'. The earliest one I
>> have in that regard is labeled '6526A 4686 206A' (not '216A').
> Interesting! I suspect that is an 8520 actually... Can you test that?

It's soldered to a C64 mainboard and behaves like a 6526A as far as the 
software goes. The 8520 doesn't have the RTC but a 24Bit timer instead 
as far as I know, so I think you'd notice if you tried to use a 8520 
instead of a 6526. It's not the only board in my posession with a 6526A 
with '206A' markings, but that's the earliest datecode.

> Supposedly they also did an 852x that has only the low four ports (or
> the rest is not functional, anyway), i.e. the two parallel ports only;
> it was called something like 5210 (I forgot the exact name, and cannot
> find it anymore).

5710 if I remember right.


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Received on 2011-12-11 21:00:17

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