Re: VIC-II DRAM refresh

On 13/10/2016 20:07, Marko Mäkelä wrote:
> Remember that the C64 KERNAL blanks the screen during tape access. I 
> think that it is possible that the memory accesses of the KERNAL tape 
> routines would not guarantee sufficient DRAM refresh.

The blank screen not fetching character pointers might be the reason, 
although VIC2 still has it's bitmap fetches that it could use.

I guess as their first dram system, they just picked what they thought 
was the easiest and safest method. It turns out that the VIC2 dram 
access was out of spec though, they sued micron for supplying faulty ram 
and it turned out the dram was faulty and the VIC2 was doing it wrong too.


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