RCA produced follow ups to its 1802 CPU, the CDP1804, CDP1805, and CDP1806. What years did they become available to purchase in?
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 reasonably accurate:
- 1802 production started early 1975 (source).
- 1804 production started 1976 (source).
- 1805 production started Q3 1981 (source).
- 1806 production started Q3 1981 (source).
Regarding the reliability, there's some contention as to the dates. For example, Wikipedia has the 1802 sampling in 1975 but not entering production until 1976. In addition, AntiqueTech has some inconsistencies, such as listing a production date of the 1801/1802 as the same year but stating in the text that the were introduced early 1975 and early 1976 respectively. Hence I suspect it would be wise to treat these dates with an adequate margin of error.