RCA 1802

COSMAC
RCA CDP 1802
General information
Launched1974
Physical specifications
Package
History
SuccessorCDP1804, CDP1805, CDP1806
RCA CDP1802 die shot

The COSMAC (Complementary Symmetry Monolithic Array Computer) is an 8-bit microprocessor family introduced by RCA. It is historically notable as the first CMOS microprocessor.[1] The first production model was the two-chip CDP1801R and CDP1801U, which were later combined into the single-chip CDP1802.[2] The 1802 represented the majority of COSMAC production, and today the entire line is known simply as the RCA 1802.

The processor design traces its history to an experimental home computer designed by Joseph Weisbecker in the early 1970s, built at his home using TTL components. RCA began development of the CMOS version of the processor design in 1973, sampling it in 1974 with plans to move to a single-chip implementation immediately. Jerry Herzog led the design of the single-chip version, which sampled in 1975 and entered production in 1976.[3][4]

In contrast to most designs of the era, which were fabricated using the NMOS process, the COSMAC was implemented in CMOS form and used static logic. This allowed it to run at lower power settings and even be stopped completely; in addition it would run cooler and not generate as much heat as NMOS chips. RCA also produced radiation hardened versions, which found use in the aerospace field.[5] These remain in production as of 2022,[5] and as of 2008 continued to be produced by Renesas (formerly Intersil).[6][7]

Successors to the 1802 are the CDP1804, CDP1805, and CDP1806, which have an extended instruction set, other enhanced features (like on-chip RAM and ROM, and built-in timer), with some versions running at faster clock speeds, though not a significant speed difference. Some features are also lost, like the DMA auto-boot loader functionality. There are also some minor pin function changes, but the line continues to be produced in its original 40-pin dual in-line package (DIP) format.[when?]

  1. ^ Cass 2018.
  2. ^ "RCA COSMAC 1802". The Antique Chip Collector's Page. AntiqueTech.com. 21 April 2009. Archived from the original on 2 January 2013. Retrieved 27 December 2010.
  3. ^ "Joseph Weisbecker". Vintage-Computer.com. 2010-02-08. Retrieved 2010-12-27.
  4. ^ "Joseph A. Weisbecker (1932 - 1990)". CosmacElf.com. Retrieved 2010-12-27.
  5. ^ a b Cass, Stephen. "Chip Hall of Fame: RCA CDP 1802 - IEEE Spectrum". IEEE. IEEE. Retrieved 19 July 2023.
  6. ^ "CDP1802A". Archived from the original on 2012-03-09. Retrieved 2010-08-23.
  7. ^ "CDP1802AC/3 High-Reliability CMOS 8-Bit Microprocessor". Intersil Americas LLC. 17 October 2008.