Re: Broken TED for

From: HÁRSFALVI Levente <>
Date: Sun, 22 Jul 2012 10:10:12 +0200
Message-ID: <>
On 2012-07-20 09:16, Segher Boessenkool wrote:

> We also know that all of the pad/drivers stuff is redone for HMOS: it
> has to be much bigger relative to the core logic; you can see this on
> e.g. the SID and VIC-II chips.
> ...
> Oh, and 7501...  :-)

The 7501 shows that the transition must have happened in a slightly more
complicated path than a supposed upgrade of the 6510 to HMOS-II, and the
derivation of both the 8501 and 8502 from that design. The 7501
obviously precedes the 8500. Unless there had been a never marketed
7500, the first HMOS (HMOS-I) 6502 descendant must have been the 7501.
Of course, the question still remains whether they upgraded the 7501 to
HMOS-II later, and derived the 8500 and 8502 designs from that, or moved
the NMOS 6510 to HMOS-II, and derived the 8501 from that once again. (Or
they just copypasted/resized parts between NMOS/HMOS-I/HMOS-II layouts
all over just as they needed; as I understand, the "conversion" between
different NMOS designs isn't very complicated, and differences between
the 8500/8501/8502 layouts are very subtle).


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Received on 2012-07-22 09:00:06

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