From: Jim Brain (brain_at_jbrain.com)
Date: 2007-12-17 22:49:24
David Wood wrote: > Sounds interesting no doubt. If youre using more than 64k RAM, would you > consider using a 65816 for linear access to the memory? I'm not trying to > turn the project into a super-computer with 16M ram. Rather, I'm attempting > to simplify buffering/ram access programming. > Wow, *WAY* ahead of me. I just pulled the parts onto a board, and made sure they would all physically fit on there. No design as yet :-) Sorry to burst the bubble. > Re-reading your reply, it would seem that the 6522 could easily be used to > control bank addressing with a 16k window if all of its lines are dedicated > to the bank address. This eliminates lines for the IEC bus though. Quite > the challenge. > Yeah, I pulled the '22 into the design simply for compatibility with SW expecting to see a '22 there. There are far better parts for banking. > Got a preview for the board's schematic someplace? :) > As noted, sorry, you're way ahead of me. If you'd like to fire up EAGLE and start, I'm happy to work with you on it. Thinking out loud: * Check out the 134 with on-board IO and such. It's not much more expensive that an 02. * I like your idea of a 816 design, but I don't know if such a design would hurt compatibility. I assume it would not any more than using IDE, but it's a deviation. * I was going to suggest the C265S as the be all solution, but not at that price. I don't pay that much for an MPU, no matter how good it is. * Someone needs to consider the amount of RAM in a design like this At some point, you need more more DOS buffers (16 or so is plenty, I think), and some scratchpad area for IDE writes. That's a bout 5kB. What else would be needed? * ROM needed. Should a drive contain a static large ROM/FLASH for the DOS, or should it contain a small minimal one and load a bunch of RAM with the real DOS and then protect the RAM? I tend to like the latter, but dunno. Jim Message was sent through the cbm-hackers mailing list
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