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I repaired my broken Commodore 64c, it appeared to be the memory, as it worked when I replaced the two ram chips with a simm module.
Now I just have to build some logic to utilize the whole meg of the simm...

My first thought was to make it +60k compatible, with some bonus to switch between different pages, not just in-or-out.

I'd love to build a 4k MMU, but that requires 128 macrocells, or it could be done with a small sram-chip. But housing everything in a single CPLD would be nice, right? And the ones I'm using just have 64 macrocells, so the decision is if I'll make it +60k compatible or more flexible, but then again I guess I have to build every driver for it myself.

+60k ain't that common you say? When I'm ready with this beast it's just a matter of soldering together a 30 pin simm and a 44 pin CPLD, very cheap stuff. Perhaps I should go for a more expensive CPLD and make this the king if internal ram expansions ;) $10 CPLD has enough macro cells, then it's just a question if it's 5v tolerant...