I have been unable to find when the MOS 8502 was first released to customers. The process it was made on was available from 1979, but MOS don't appear to have used it for their own parts at that time.

The 8502 was used in the Commodore 128, released in 1985. Was the 8502 available earlier than that?

  • 6
    I don't know either way,but Wikipedia seems convinced about an 8502 existing, and being used in the C128.
    – dave
    Commented May 11, 2023 at 11:27
  • 1
    I'm building a family tree and Wikipedia doesn't have a date for the 8502. It also mentions the 6507/8/9, and I have found some datasheets for them, but no release dates.
    – user
    Commented May 11, 2023 at 12:08
  • 1
    Related: retrocomputing.stackexchange.com/questions/12639/…
    – Jon Custer
    Commented May 11, 2023 at 12:36
  • 1
    Seems to be some traces out there: myoldcomputer.nl/Files/Datasheet/MOS8502.pdf (seems to be extract from another datasheet) Seems from a quick search that it was only used in the commodore 128
    – UncleBod
    Commented May 11, 2023 at 12:36
  • 1
    1985 seems like a smart guess on the basis that MOS used the '8' prefix to indicate an HMOS-II process and all of the other 8-series chips seem to have first arrived in 1985 — via the Amiga and the Commodore 128. Wikipedia also specifically claims a 1985 introduction for the 8500, the 6500 equivalent, but doesn't provide a source so that can't be verified.
    – Tommy
    Commented May 11, 2023 at 13:59

1 Answer 1


I just talked to Bil Herd (the designer of the C128 hardware), and he said, "It was made specifically for the C128, design mods done by Dave DiOrio," and so was essentially "released" to the sole customer (the C128 team) in 1984.

It was never used outside CBM, and indeed never used in anything but the C128. (There seem to have been a fair number of ostensibly "MOS" chips with really skimpy datasheets that were like this.)

  • 1
    Should be able to give extra points for the WOW! :-0 mind blown factor...
    – chthon
    Commented May 15, 2023 at 7:32

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .