... which includes a bbc basic for 6809
https://github.com/dominicbeesley/beeb6809/tree/master

Also you might be interested in Mike Kohn's recently developed 65832 (as found by Jeff) which of course also includes a 65816 mode as well as a 65c02 mode.
https://www.mikekohn.net/micro/w65c832_fpga.php

... have booted it under Linux, but I didn't)

I think what I'd like to investigate are extensions of the 6502 into the 32 bit realm. Not exactly the 65832 discussion (which didn't seem to drive all the 8 bit diehards away), but something along the lines of 6502 inspired macros that would expand to ...

... to ARM and RISC-V and the lessons learned. I think what I'd like to investigate are extensions of the 6502 into the 32 bit realm. Not exactly the 65832 discussion (which didn't seem to drive all the 8 bit diehards away), but something along the lines of 6502 inspired macros that would expand to ...

... through custom instructions) to run some piece of code somewhere in memory seems like a good alternative.

also, personally i wouldn't bother with 65832 compatibility, as it's just a 65816 with 32-bit registers and no other redeeming qualities or software that made use of it.

anyways i'd be ...

... through custom instructions) to run some piece of code somewhere in memory seems like a good alternative.

also, personally i wouldn't bother with 65832 compatibility, as it's just a 65816 with 32-bit registers and no other redeeming qualities or software that made use of it.

anyways i'd be ...

... correctly, a RISC-V implementation with a 'user extension', that is operationally compatible with the 6502, 65816 and ideally, the never released 65832, or versions for each thereof.

I would restrict any other extensions to RISC-V at this level as a package much like the existing nomenclature ...

ahhh the dreams of a 32-bit 6502 CPU. i have been working every now and then on a draft for my own flavor of 32-bitness.
re-reading the 65k project pages, i can see some similarities here and there. but i think my design is distinct enough to not be called a copy...

for example my design does have ...

... I have looked briefly at a few of the 65x+32 projects out there. I have read through the 65832 datasheet and around this board 'some'.
Because this topic is kinda hot and this is as good a place as any to jump in, I want to discuss a few ...

... requirements for the '816 to be able to run '02 code however seems to have kept the '816 from being as good as it could have been. WDC designed the 65832 also, apparently for such a market, but Apple went to the 68000, so the 65832 was never made. The '832 had an 8-bit data bus. Someone asked Bill ...

... 25.175MHz display may partially fail. This is an annoying corner case and extra circuitry for 65816 is likely to be insufficient for a hypothetical 65832. There is a common pattern here: draw everything twice or draw everything slowly so it can be sampled twice.

We also have the problem that reads ...

... cycle. However, if you depend upon such undocumented functionality then your design may not be upward compatible. For example, if a hypothetical 65832 became available and 65816 chips were derived from the same manufacturing process then EMU pin functionality may change quite drastically. Such ...

There are at least 10 groups who have proposed a 32 bit extension or larger. This would include 65k, 65000, 65020, 65GZ032 , 65Org32 , 65832 , 65E4 , 65m02 and tentative steps separately from Proxy and I to extend 65CE02. It is apparent that many of the proposals have common themes and they typically ...

Yes, it is a KiCAD schematic. Thanks for the suggestion, I was able to plot a monochrome image of the board schematic so far. I still need to add RAM, ROM, and a uart to make it a SBC.

(Sorry about the color, I haven't figured out how to get the CAD program to output mono.)


It looks to me like you took a screenshot of the Kicad schematic window?
If you instead go to File -> Plot, you can create a PDF of the schematic, and one of the options is "Output mode" (Color | Black and ...

Spent some time studying and coming up with a circuit interfacing interrupts for an '816 processor.
In emulation mode interrupts are handled via ROM vectors as normal. The interesting part occurs for interrupts handled in native mode.
The encoded interrupt level (one of sixteen) is used to form part ...