There was discussion on 6502.ORG about replacing the 6509 with a 6502.6502.org • View topic - MOS 6509 look-alikes? | | | 6502.org • View topic - MOS 6509 look-alikes? | | | The consensus was that it's doable. I think it would be a great idea. The other alternative is just making an FPGA version. Since an FPGA 6502 is already available it would be fairly trivial to adapt it to do 6509. A CBM-II replica/clone/with enhancements is on my todo list, but at my pace I wouldn't hold your breath ;-) Steve From: Mia Magnusson <mia@plea.se> To: cbm-hackers@musoftware.de Sent: Saturday, November 4, 2017 10:22 AM Subject: Hardware emulation of 6509 using 6502? Hi! Just a crazy idea: Since I assume 6509's are rather hard to get a hold of, and since the 6509 (and to some extent 6525 and maybe 6551) is the only "hard to get a hold of" IC in a CBM-II computer, it might be a nice idea to make some kind of logic to make a replica. Maybe this is a bit too hard to actually do, but my idea is to keep track of what the CPU does and detect the LDA and STA Y-indirect instructions and then temporarily switch in the relevant bank during the correct cycle. Maybe this won't be cycle exact (as I understand from the data sheet of 6509, the cpu actually does a read from adress 1 or 0 when it needs to switch the output on the bank select pins, and those cycles won't be needed with external hardware). What do you think, would this be feasable? Would it even be a good idea to make a replica of a CBM-II computer? -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies. Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2017-11-04 15:02:00
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