I'd suggest that WDC own only the mask copyright for the particular 65c02 chips they've made. Just possibly they have patents, but I doubt it. And there's no trademark question. So, I'd say anyone can freely make a 65c02, either exactly like WDC's or a variation on it, as they see fit - so long as they don't try to pass it off or use WDC's name. (You could even copy the mask design by examining a WDC chip, so long as it's at least 10 years old.)

Edit (much later): as this is my first post in this thread, I'm going to use it to dump some recovered text from posts now deleted, posted by the OP, Giebels2609. Perhaps see also these archived pages: 1, 4.

Of course these quotes lack some context, but still I think worth preserving.

What is the end market?
Replacement parts for vintage equipment, or to feed a community that wants to explore / re-live the beginnings of the home computer era?

If your goal is replacement parts, then why not invest in some keyboard / case knockoffs for the C64 / VIC20?
There are endless plastic injection hoses in China, and your investment might only be 10k in tooling to run 1000 units.

The MOS chips are easily replicated in HDL now, so they will never die. A C64 keyboard on the other hand, is on borrowed time already.
Those switches will eventually wear, and the print on the keys will fade into oblivion.

Have you done any kind of market study yet?
I would be interested in the results, as I was shocked at how many offered to purchase one of my projects here.
Still getting many emails per week!
Seems there is a market that I would have never expected for the "old tech"!

Brad

Maybe including other chips (z80, 68000, etc you might get enough orders to sustain a market.

I wonder what the price point would have to be?
The Propeller was a surprise to me when it came out, since it was targeted just to hackers like me.
They considered the market large enough, and I believe they have done more than one batch, so they must have been correct.

"New Old Chips" might be a smaller slice of pie to go after though.
But then again, there are places remaking 57 Chevy parts, and the C64 is also a classic!

A few years ago I actually considered doing a 6502 clone on a Xilinx CPLD (XC2C256), allowing it to clock up to 100Mhz.
The idea included a DIP board, and a supporting DIP mounted 64K of SRAM that could be serially loaded.
If I remember correctly, my total cost for the 6502 board would have been around $20 to make 1000 units.
But would there have been a market? How long would it take to make a 15% margin on the 20K investment?
I guess if you are doing it because you just enjoy it, then it's all good. Money isn't always the end goal.
The "big players" will never care enough to give you any competition. Even the China pirates wouldn't take notice.

Manufacturing anything is a Rich Man's game though. Be prepared.

Brad

You've touched on a murky area. Bill Mensch is a co-inventor listed on the original 6502 patent, but like all patents from that era, it has long expired. The 65C02 design was released in 1978, so any patents on it would have also expired.

The intellectual property involving the 65C02 is another matter. That is covered by copyright, which as you know, extends to beyond the death of the original copyright holder. In theory, it would seem that producing a 65C02 knockoff would violate copyright. Who knows for sure? This sort of thing is what keeps lawyers employed.

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

I wonder if a a chip that can run 6502 instructions would count as a knock off?
If so, how much would have to change?

Remember Ubicom?
They may these amazing PIC8 compatible chips called the SX series.
They ran the PIC instruction set, but would clock up to 100 MHz!
This is what a uC should be, and I jumped fully into these back in the day.
It was like having an 8 bit PIC that would keep up to an FPGA. Great for video stuff.
Anyhow, they didn't get sued by Microchip. They just went extinct.

If someone pressed out a "compatible" 6502 with these features, I would be all over it!...

- Clock speed up to 100MHz.
- Every instruction to be single cycle.
- Flash based 64K memory (yeah - no frickin' ROMs baby!).
- Flash copied to fast internal 64K SRAM on bootup.
- Loading via standard SPI, JTAG, or modern standard.
- Unused Address and Data Lines now become IO.

So listen up Giebels... make my dream 6502, and I will invest in your company big time!
I will offer distribution, advertising, kits, and more publicity than you could ever imagine.
Forget Liberland man, and make me a SUPER-6502!!

Sorry.. I was getting cranked up on what could be done with such a monster 6502.

Brad

Depends on who has the most $. Look at all the prior art copied from Palm's ideas that Apple put into their crappy phones and then sued and won against anyone else who did similar. I had hoped maybe HP would get back in the market when they bought palm and were buying palm to beat Apple.

"Intellectual Property" is a vague term which serves to collect specific protections: patents, trade marks, copyrights, design patents. None of those apply here. It might be a useful personal policy to steer clear of anything which might possibly be problematic, but it's not hard to understand this area if you want to be more precise when discussing it. Of course you'd get legal advice if starting a business, but that's again a different question. There's nothing in WDC's 6502 older chips which could still be copyrighted. (Of course, they do have copyright in their documentation and their tools, but that's a different question.)

Just make sure not to call it a "65c02". "6502" _might_ be doable as protecting model numbers isn't really a thing, but still sketchy. "The $MY_CHIP is intended to be compatible to the 65c02. ["65c02" is a trademark of WDC and we have no affiliation or endorsement from them blahblah]" or whatever is typically what you get.

This is the reason Intel went from "80486" to "Pentium", because a name could be trademarked but not a number. This meant AMD and Cyrix couldn't name their chips the same as Intel anymore, as was possible with the "486" or "80486".

_________________
WFDis Interactive 6502 Disassembler
AcheronVM: A Reconfigurable 16-bit Virtual CPU for the 6502 Microprocessor

Yes, that's the sort of thing you'd get legal advice on if in business.

I may be wrong, but I don't think they would have any right to "65c02", but probably "W65C02".

In any case, the OP said several times that he's looking at the 6502, not the 65C02 (although if it would be NMOS I'm not so sure.. as masks would have to be created from scratch anyway it wouldn't have to be NMOS).
Not sure where the market would be for that though.. I wouldn't buy a 6502, and for a +14MHz 65C02 we have WDC already (and I have enough WDC chips in the drawer to last me for some time).

The point I was trying to make is be prepared for lots of legal issues, because anyone can sue anyone else for anything and I'm sure re-creating a 6502 could hurt WDC's sales and you may end up in court having to proove you didn't use anything from the C02 that WDC owns.

Of course, given that WDC is fabless and likely sells vastly more units of chip IP than physical processors, and that the OP is not in the same country, there might be little impetus for WDC caring at all.

But it's always good to do your best to pay proper legal respect, instead of pushing the issues.

_________________
WFDis Interactive 6502 Disassembler
AcheronVM: A Reconfigurable 16-bit Virtual CPU for the 6502 Microprocessor

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?