Re: Could you make a 'new', 'better' computer from the C64 just by reprogramming the PLA?

On 11/3/2021 4:37 PM, Claudio Sánchez wrote:
>> VIC2 cannot use color ram in DRAM at all. The VICII data bus is 12
>> bits wide, but is shrunk to 8 bits during cpu cycles by a 2x4 (4066)
>> switch to allow the cpu access to color memory.  Using DRAM for color
>> memory would require adding more DRAM to the system.
>
> I think that was a solution of compromise so they could stop tinkering 
> with the address decoding logic. Why should it be a problem to have 
> color RAM mapped in DRAM in the first place? They had to include a 
> SRAM chip in *every* computer (later revisions would have it included 
> in that SHARP chip).

I always thought it was done because there were moments when getting 8 
bits at a time would not pull enough data into the VIC-II to make the 
display work.

Jim