Hello, new to this forum but not new to 80s tech and computers. I've read the forum for years but became a member only yesterday. So much good info and many great discussions!

My first computer was a ZX81. Still my favourite retro platform, even if Z80 is not my preferred assembly version.
Lots of other old computers have been in my possession, and I've played with HW and SW on many of them.
Low level programming, mechanics and electronics is what I do at work and home, though on different platforms.

My latest foray into the land of 6502 is the PZ1 laptop. Started out as a pure SW emulation on a Blue Pill, latest version is a Teensy 4.1 and a W65C02 with memory and bank registers coming up. If I ever get ATF750 programming working on my Dataman S4, some glue logic will make the PZ1 even faster. Much of the HW design choices are done to better understand the limits and possibilities of multi tasking on the 6502.
Would love to discuss the PZ1 here, but a separate post is probably better. Link to the project log for the curious https://hackaday.io/project/171471-pz1-6502-laptop

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/NollKollTroll

Welcome! Nice project. I do like embedded emulations, and using an MCU to act as glue, and/or memory, and/or IO channels, is an appealing approach.

That looks like a neat project.

I have a suggestion, though. You mention that the source code is not released because it's "[t]oo ugly and hacky for public scrutiny/use." I would suggest you release it anyway, because unreleased source code, even if it's not in great hape, has several deleterious effects:

1. Even code that is poor in some ways often has good ideas in it that others could use; if such a good idea would make someone else's code better, but you've hidden it, you've now contributed to having yet more poor code in the world.
2. Various events can cause projects to stall for long periods or even stop permanently; if this happens before you make the code available, the code is lost to the world.
3. It indicates to beginners that it's correct not to show your code to anyone until it's "good enough to show," which slows down their development and learning (sometimes even stopping it completely, if they never feel that their code is good enough to show).
4. It can make beginners feel that they're somehow bad people for having written bad code, rather than demonstrating to them that lots of code (perhaps most) starts out bad and is improved, rather than starting out as "good" code.

If your goal is to contribute something to others, as well as have fun building your project, it's always worth asking yourself, when hiding something about your project, "how do others benefit more from this being hidden than open?"

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Curt J. Sampson - github.com/0cjs

Re: getting the ATF750 to work with your Dataman S4.

I also use a Dataman programmer, albeit the 40Pro. Turns out that to program the ATF750, you need to add a 0.1uF cap across the power pins on the ATF750. Dataman do sell an adapter for this, but is ridiculously expensive. I just keep a 0.1uF cap with insulated leads and place the lead ends in the socket with the ATF750. To date, no issues programming them.

Hope this helps.

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Regards, KM
https://github.com/floobydust

Cjs: I agree with you, I've just had too much fun by myself instead of sharing. I'll retrace what code is used from where and give proper credit.

Floobydust: I have not gotten the ATF750 programming working with your suggestion. I'll try again later, but for now I'll use the Teensy to do all the glue logic functions.

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/NollKollTroll