I am currently working on (and have nearly finished) a complete svg circuit diagram of an nmos 6502 processor, inspired by the work of Beregnyei Balazs and BreakNES, and using (of course!) the visual6502 as well. I would like to release this under a permissive copyleft license. I would be grateful for information on what licenses are used by these works, so that I can use an appropriate license (with appropriate attribution) myself.

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Davidmjc

Welcome - sounds very interesting!

All the visual6502 original information - the content with copyright by the visual6502 team - is MIT licensed.

I contacted Balazs in the past and he was happy for us (visual6502) to republish his work with attribution. That's not to say that what we republish is then licensed for anyone else to use. Balazs said to us:


At the time I was thinking we might be able to animate his circuit diagram, or maybe somehow make use of the locations of transistors, but we didn't do it. It would still be interesting to see it done!

Many thanks for the welcome and reply! Yes, with an svg, a bit of CSS and/or Javascript can do a lot. I have used it to highlight nmos circuits on mouseover or click. I attach a thumbnail as a taster.

This work relies primarily on Balazs' schematic, with the visual6502 and BreakNES for cross-checking and additional information, so it seems to me that the Creative Commons Attribution Non-commercial Share-alike licence used by visual6502 would work best. My proposed attribution is "Based on schematic by Balazs Beregnyei, with additional information from visual6502 and BreakNES". Do you have the email for Balazs, so that I can include it per the above request?

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Davidmjc

Just to say that I found Balazs gmail address.

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Davidmjc

That's great - I've been away from keyboard. I'd recommend you contact him and get suitable permission for your project. It's highly likely he'll be amenable, I think. I don't think you can inherit from the permission he gave to visual6502.

I did as you suggested, and as you predicted Balazs was happy for me to use his work in this way. In the meantime I tidied up the svg a bit, so that it is 1.8MB (raw text). That should go down a bit as I improve the identifiers of the individual elements.

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Davidmjc

Great!

I now have a publishable draft, but the forum does not allow svg attachments. Is there a way to make it available to other members of the forum? The file is 1.7 MB.

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Davidmjc

Perhaps upload to github or dropbox or similar? I tend to use github, because you can configure a repository also to be a website, which serves static files from a subdomain of github.io - that's very handy.

I am new to github, but I think I succeeded in doing this at https://davidmjc.github.io/6502/

If that looks okay to you, I will start a new post with a link and a brief explanation. Many thanks!

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Davidmjc

You can link directly to the .SVG file using this URL

https://davidmjc.github.io/6502/cd.svg

Well done!

Thank you both - I am just adding the cc-by-sa license information (although it is in the source code) for clarity

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Davidmjc

Wow, great stuff! Thanks for sharing. Exactly what I needed.
I think I found some minor errors in instruction pre-decoding, PD-xxxx10x0 and PD-0xx0xx0x have wrong values I believe.

Many thanks for both the comments and the correction. One of my motivations for making the diagram freely available was in the hope that others might spot some of the many errors I undoubtedly made! I have cross-checked against the visual 6502, and believe I have now fixed the circuit. I believe also BreakNES has the right circuit, but Balazs has a different one. My mistakes are different from the the ones in Balazs' diagram, so I have no idea how I made them!

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Davidmjc