I am getting good results with using Claude for debugging. I have huge trace files from my emulator and it is very tedious to look through them to determine where the code path goes wrong. This is an excellent use for AI.

In general I find AI very useful, but you have to work closely with it and ...

I'm not sure if the 6500/1 was a MOS design or a Rockwell design, but the Rockwell version has a lot more documentation. This includes emulator devices with a piggyback socket for an EPROM, for development, and I think there is one packaged with extra pins for an external bus for a ROM only. They ...

Thanks for sharing the video and the source code. It's always interesting to see code running on real hardware at 6502 speed.
Your point about RECURSE working well is a nice reminder of how elegantly FORTH handles recursion for these kinds of fractal patterns.
What strikes me about Turtle Graphics ...

Going to me actually. I'm mainly interested in the AIM-65, but the MICE-II looks like it could be a useful device, as long as I'm only working with a 6502, but maybe it could be upgraded to a 65C02? Might be interesting to work on a modernised version too, although probably emulating the 6502 could ...

If you haven't already read this, Synertek app note 3 has useful information on the various ways of interfacing to the 6545.

I particularly like the example of using the 6545 address lines as a keyboard scanner.

With the release of MS-Basic source under the MIT License I believe that this now means that EhBasic is legal as a derivative work, if that is the case, so that issue now goes away. Scanning through this topic it appears that Lee licensed EhBasic for non-commercial use, so anyone that did have ...

Microsoft has released the source code to 6502 basic with build flags for Apple II, Commodore PET, OSI and KIM-1. The source is on GitHub. https://github.com/microsoft/BASIC-M6502

Information from Microsoft:
https://opensource.microsoft.com/blog/2025/09/03/microsoft-open-source-historic-6502 ...

A cache may solve the bus width and alignment problems while still looking simple from the programmers view. This does significantly complicate the hardware, but would make it easier to use modern SDRAM.

I guess I have good timing - this thread is alive! I've been trying to use Quartus II to demux a 65C816 (data and bank) using an ATF1504as 7.5ns, but to no avail. I switched to WinCUPL, but I feel like I'm banging my head against the wall. I'm sure people have done this before; but I just can't get ...

I hadn't used my Rockwell Forth system for a while, and now that I've powered it up again it doesn't work. After a short investigation it looks like the CPLD isn't working. I can pop it out of its socket, power up and get the same result as when it's in the socket. It's there mainly for the address ...

There are two versions of the PDF in the wild. The older of the two has a number of errors that crept in during the process of digitizing the original. Around 2015, WDC sacrificed an original paper copy and OCRed it into a clean and searchable PDF, which is what is available for download from the ...

As another view on zeropage, it's also common to have a subsystem (say, a set of floating point routines) which use some area of zero page as a scratchpad (say, two or three multibyte values.)

Indeed Sweet16 is such a subsystem, but I think that's more often mentioned than actually used!
Yes, I'd ...

The 816 should have had an instruction such as PLW to remove a word from the stack without clobbering a register.

It does appear to be an omission to not have push and pull stack pointer instructions, this would be a simple way of clearing a stack frame. As you show in your comment, you'd still ...

I do like that comment. We're all basically here because we like the 6502, so why try and change it to look like something else?

There has been quite a bit of discussion of the lack of registers on the 6502, and the idea of thinking of zero page as a very large register file. To add weight to this Bill Mench has called this 'Addressable Register Architecture'. And it is a relatively common technique to define some zero page ...