Re: Differences between 8501R1 and 8501R4

From: Frank Wolf <*webmaster_at_frank-wolf.org*> Date: Thu, 5 Dec 2019 13:00:07 +0100 Message-ID: <6595510e-6399-e08e-e0eb-92d7b7281071_at_frank-wolf.org> · webmaster_at_frank-wolf.org

On 05/12/2019 12:46, Gerrit Heitsch wrote:
> The reason could also be the year they were made in. In 1984, HMOS-II 
> was pretty new, at least at MOS and the 8501 and 8360 were about the 
> start of doing HMOS-II at MOS. In 1986 they probably had the process 
> figured out and stable so the 8501 made then do hold up better. After 
> all, the earliest instances of the 8500 appearing in a C64 were in 
> 1985 and those were not known for causing problems.

I'm quite sure that the masks for the 8500 were made AFTER the ones for 
8501 or at least at the same time:

The die of the 8500 contains obstacles which only make sense for the 8501!
Would be nice to see the layout of the 7501...