RCA produced follow ups to its 1802 CPU, the CDP1804, CDP1805, and CDP1806. What years did they become available to purchase in?

  • 5
    Hmmmm.... Seems like we should find an EE Times archive and a student intern to comb through them noting all microprocessor announcements?
    – Jon Custer
    May 25 at 14:16
  • @JonCuster: Or else find someone who would have been involved with projects that used them, and might have information about the evolution from "product that is being considered" to "product that is being manufactured in production quantities" which could not be found in press releases.
    – supercat
    May 25 at 16:31
  • @supercat - well, this is the third similar question asking about different families of microprocessors in a week...
    – Jon Custer
    May 25 at 16:32
  • @JonCuster Did chatGPT read the EE Times archive? If so, we can ask it. :)
    – doneal24
    May 25 at 16:53

1 Answer 1


Well, we can at least establish a latest date for them. The RCA Solid State Databook for CMOS Microprocessors, Memories and Peripherals has a copyright date of 1984 and the text "Printed in USA-10/84" on the information page at the start of the book. It lists various versions of all three extended CPUs (1804/5/6).

Given the production dates later in this answer, that's about as useful as saying they were all available in 2022 :-)

The 1804 and 1805 were both described in the Microprocessor/Memory Application Briefs document, dated July 2nd, 1981. That book lists the latest datasheet for the 1804 as 8/79 so it would probably have been available at that point.

In terms of a bit more detail, the AntiqueTech website has the following information on these chips. How reliable it is I'll leave up to others but they appear to have a great deal of useful information so are likely accurate:

  • 1802 production started early 1975 (source).
  • 1804 production started 1976 (source).
  • 1805 production started Q3 1981 (source).
  • 1806 production started Q3 1981 (source).
  • Thanks. The 1801 and 1802 are both listed as 1975, which can't be right. Surely they didn't introduce the 2 chip and 1 chip versions the same year. Wikipedia gives 74 for the 1801 which makes more sense.
    – user
    24 mins ago

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