Try this one ;) Use a 64kx8 staic ram, hooked to the cpu's A14,15 and otherwise hooked to the vic chip's control lines. This will get you full vic access to all expansion ram. Now to un-decode the static ram while other devices are accessed ;) All you have to do is take the chip select lines or the roms and the I/O spaces, feed them to a huge NAND gate, invert the output, and apply to the output enable and/or write anable lines :) The chip selects can be swiped from the 74ls138's near the userport. two ICs, 35k expansion ram. With a couple more ICs, even bank-switchable for another 16-24k. It seems like a waste of memory space, but at a buck for a few million bytes, what the heck? :) On Mon, 8 Jan 2001, MagerValp wrote: > I'm working in upgrading my Vic-20 with some extra ram to be able to > watch (and digitize) Veni Vidi Vic and Vici Iterum MM. I'm aiming for > the least amount of chips and wires possible, which is why I'm piggy- > backing 6264's onto the kernal and basic rom. I'm also thinking about > adding a 3K expansion by piggy-backing 2114's onto the existing ones, > but I'm having a hard time finding the chips. The best price so far is > $7.50 per chip -- ie $45 for a measly 3K :) It's worth it? Is there > any software out there that needs it? Does anyone know of a cheap > source for 2114? > > -- > ___ . . . . . + . . o > _|___|_ + . + . + . . Per Olofsson, konstnär > o-o . . . o + MagerValp@cling.gu.se > - + + . http://www.cling.gu.se/~cl3polof/ > - > This message was sent through the cbm-hackers mailing list. > To unsubscribe: echo unsubscribe | mail email@example.com. > - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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