When Nintendo used the 6502 core in the NES (as part of the Ricoh 2A03/2A07 microprocessor and sound generator), they circumvented the 6502's patent protection by disabling the BCD arithmetic. As a result, Commodore -- holders of the 6502 patent after they bought MOS Technology -- did not receive any payments for the use of the core.

Later, Nintendo used the 65816 core in the Ricoh 5A22 that powered the SNES. Did they pay WDC, who developed the 65816, for this, or did they find a similar loophole?

  • This is an aside to the question - but how in the 1980s was it seen fit to award a patent for having BCD arithmetic?
    – dave
    May 21, 2020 at 23:40
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    It was the 1970s and it wasn't for BCD arithmetic in general, it was for a BCD implementation without a performance penalty. patents.google.com/patent/US3991307A/en May 22, 2020 at 1:25
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    Wikipedia claims the SNES CPU was based on the CMD/GTE 65c816, which was itself based on the WDC chip. Following that logic, they would have had to pay GTE rather than WDC.
    – tofro
    Jul 27, 2020 at 21:15
  • @tofro Either way, it would still be based on WDC IP, so the question still stands: Did money flow from Nintendo to WDC, either directly or through CMD / GTE? Jul 31, 2020 at 13:48

1 Answer 1


William "Bill" Mensch exclusively designed the chip to Nintendo, and the interview of Bill Mensch leaves lots of question marks, but his motto was that both sides would benefit from the deals. Quote: "Ricoh supplied the Nintendo. It's the only exclusive agreement I ever gave anyone, exclusively for Ricoh to supply Nintendo 8/16-bit chips for their SuperNintendo. Well, my son got a Super Famicom."

Another quote: "And "I licensed Ricoh the camera and copier company of Japan. I gave Ricoh an exclusive license on the W65C816 processor for use in a Nintendo game system. That exclusivity meant the I would not license anyone else to manufacture a W65C816 for Nintendo, an exclusivity for only one company, Nintendo." As far I know, you could seize sales at least in the United States if there is a problem with deals like what Amiga Cd32 sales happened.

And little off the topic: "I licensed a company in Taiwan on my W65C816 design that has built probably about a billion game system chip over the years, many times what Apple and Atari combined ever sold. Those systems are still being sold to this day. I received royalties off every one sold."

So it is not a direct answer but I cannot find information that Ricoh did not honor their deal. He has made a statement in one interview that Jack Tramiel was ripping him off. That state would possibly indicate that he had better deals with others, or would at least mention if there was a problem with licensing associates.

  • Too early post. Sorry for that. Still new here.
    – Petri-fied
    Aug 6, 2020 at 15:16
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    That post from Bill sounds a bit delusional in places — "probably Apple could still be selling interesting education computers and Atari could be selling interesting game systems to this day if they would have considered working with me."; even if the Taiwan comment is accurate then trying to find anything much beyond a IIgs or SNES with a 65816 or derivative by searching the MAME source code didn't turn much up. Though it looks like Namco might have used a derivative as a minor support chip in the System 11 and System 22.
    – Tommy
    Aug 6, 2020 at 19:48
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    @Tommy I think "delusional" is a bit too strong here. If WDC had been significantly more successful, then they could easily have ended up in a serious competition with ARM in the early days. ARM was a "spiritual" successor to what WDC was trying to do in a technological and in a business sense. And we all know what happened with ARM.
    – Brian H
    Aug 7, 2020 at 13:03
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    @BrianH in the same post he also claims that Acorn asked him first to design the ARM, before then reaching out to Apple when he declined, which is the opposite of the way anybody else tells that story — Acorn designed the chip, used it for several years, then eventually Apple came knocking. He then goes as far as "So you see, Apple and Atari had their own ideas and NOT working with me was one of those ideas." — note the distinction between that statement and 'working with me was not one of those ideas'.
    – Tommy
    Aug 7, 2020 at 13:13
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    @Tommy All good points. I just don't think Mensch being very choosy on partnerships/projects qualifies the pejorative of "delusional". It is certainly not above critique. It's nothing unusual for a highly skilled engineer to be not equally skilled at business dealings. I'm basically defending the man's character here, not trying to rewrite any history. Wondering if ARM could have happened differently is just showing empathy for his statements without making excuses for them.
    – Brian H
    Aug 7, 2020 at 13:27

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