The Wikipedia article on the 65C02 is missing an introduction date for any of the mentioned models. I did a bit of poking about with no success. Does anyone know when they were introduced?

  • I suspect the Synertek, Rockwell and WDC 65C02s may have been introduced at different times since the instruction sets differ slightly. This, unfortunately, is all I'm capable of adding to the conversation.
    – Tommy
    Commented Jun 27, 2019 at 19:17
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    The Rockwell 65C02 was mentioned in an ad in Micro 6502 Journal, May 1983: archive.org/details/micro-6502-journal-60/page/n71?q=65c02 Commented Jun 27, 2019 at 19:41
  • Excellent snips. Given publishing delays, I'd estimate 3 to 6 months earlier? Commented Jun 27, 2019 at 19:48
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    Hard to tell, WDC was founded in 1978 and the earliest mentioning of the C02 in their papers I have is 1981
    – Raffzahn
    Commented Jun 27, 2019 at 22:31
  • @Raffzahn-that's interesting - the Wiki article claims they began development in 1978, but I'm not sure that's correct. 1981 seems more likely given an intro date about two years later. Was CMOS even a thing in 1978? Commented Jun 30, 2019 at 12:25

1 Answer 1


The June 1983 issue of Softalk magazine carried an article on the 65C02. It opens as follows:

This month's discussion deals with a new version of our beloved 6502 microprocessor known as the 65C02. Although the chip has just been released within the last few months and has yet to find its way into the mainstream of computers, it seems likely that we'll be hearing more about this item in the upcoming year.

It goes on to say:

As sometimes happens with these things, though, some of the key persons involved with the 6502 went to work at a new company. Western Design Center. This company, then, is the original source of the new 65C02 chip. But the story doesn't end there. Western Design Center has sold the design to at least three independent manufacturers, Rockwell International, GTE, and NCR. These companies took the initial 65C02 design, corrected initial design errors, and added their own enhancements.

The picture at this point is that each of these three companies will be marketing its own version of the 65C02. The chips are more or less the same, but the Rockwell chip has the largest instruction set.

The same magazine includes the following advert:

Southwestern Data Systems advert for 65c02 upgrade for Apple IIe

There are no results from 1982 or earlier in a text search of archive.org, so I conclude that the 65c02 was introduced in the first half of 1983.

Post Script: Southwestern Data Systems produced a booklet on the 65C02 (copyright date 1983) which reproduces the Softalk article almost word for word. It also includes a description of the instructions, and a copy of Rockwell's datasheet for the R65C02.

  • I think Softalk weren't quite right on that final point; as I understand it the Synertek is the least featured 65C02, although it still has 95% of the added stuff like INA, DEA, a JMP (abs) that works across page boundaries, etc, the Rockwell improves on it by adding the bit instructions BBR, BBS, RMB and SMB, but then the WDC goes one better by including everything the Rockwell has but also adding STP and WAI.
    – Tommy
    Commented Jun 27, 2019 at 21:43
  • WDC's W65C02 includes BBR, BBS, RMS, and SMB. WDC's 65C02 does not. Commented Jun 27, 2019 at 23:12
  • @KelvinSherlock Err ... that sentence doesn't make much sense - that is unless you change one of the occurrences of 'WDC' to some other manufacturer.
    – Raffzahn
    Commented Jun 27, 2019 at 23:43
  • @Raffzahn Note the "W" in "W65C02" vs "65C02".
    – user461
    Commented Jun 28, 2019 at 18:55
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    So is it possible to know WHEN the bit fiddlers were added? It seems that both WDC and others had versions without them, but I’m not clear if there was a design reason for this or it was because Rockwell added them and WDC back-ported for the W version. I SUSPECT the later, but I’d like confirmation one way or the other. Commented Jul 1, 2019 at 14:13

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