Our main priority should be a drop-in 6509 substitute. That would revive many perfectly good CBM-II series machines and either expand the user base or at least keep the existing user base happy. I think using a 65816 would make it an interesting bonus. The CBM-II series seems to be all about RAM and the 6509 was Commodore's quick-and-dirty solution without going to 16-bit and having to redesign everything. The 6509 was an ok processor for the time, but the CBM-II architecture/implementation around it seems to be it's limiting factor. It definitely needed more usable RAM in BANK15. A 65816 and a little magic could turn the 64K RAM BANKS into linear addressed space with a much more powerful CPU. It would make the machine much more interesting to play with for sure. I don't know enough about the 65816 to know what would be needed to fix/re-write the KERNAL to take advantage of it. In any case, in my books ANY CBM-II project is a GOOD project ;-) Steve From: Mike Naberezny <mike@naberezny.com> To: cbm-hackers@musoftware.de Sent: Thursday, March 15, 2018 8:38 PM Subject: Re: Hardware emulation of 6509 using 6502? On 3/15/18 4:00 PM, Jim Brain wrote: > Isn't "pursuing" just the act of ordering one from the original site? This was in response to Jeff Laughton's suggestion on this thread that the 6502-to-6509 adapter concept could be done as 65C816-to-6509. I'm not sure what original site you're referring to. > I counter that one can address the limitations of the B series memory map > without resorting to a new CPU. Sure, but a 65C816 would be neat and from Jeff's description would not add much extra to the design. Regards, Mike -- Mike Naberezny (mike@naberezny.com) http://6502.orgReceived on 2018-03-16 04:00:03
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