Path: utzoo!utgpu!attcan!uunet!husc6!mailrus!cornell!uw-beaver!tektronix!sequent!jjb
From: jjb@sequent.UUCP (Jeff Bob Berkowitz)
Newsgroups: comp.arch
Subject: RCA 1802 (was: PC history)
Summary: History: the RCA 1802
Keywords: history, pc, RCA, 1802
Message-ID: <3884@sequent.UUCP>
Date: 3 Aug 88 03:52:58 GMT
References: <5458@ecsvax.uncecs.edu> <1876@looking.UUCP> <753@applix.UUCP>
Organization: Sequent Computer Systems, Beaverton, OR
Lines: 28

In article <753@applix.UUCP>, scott@applix.UUCP (Scott Evernden) writes:
> 
> My Cosmac-clone (anyone remember the BYTE ads for the Quest ELF?) was
> one of the funnest toys I ever had.  16 absolutely general-purpose
> 16bit registers, etc. etc...
> 
> -scott

The 1802 was an important achievement.  Its strange architecture was clearly
imposed by the requirement of packing an entire CPU on a single chip using
mid-1970's CMOS technology (10 micron lines? - can anyone correct me?).  RCA
data books from that era listed an earlier device, the 1801, which was split
across two chips.  Was the 1801 ever produced?  Rumor has it that parts of the
instruction set - in particular, autoincrement addressing - were much more
"sensible" until DEC threatened to sue for infringement on the PDP-11 design.
Is there any truth to this?  Chrysler used the device in the difficult
"under-the-hood" environment for years - true?

For many years, the 1802 was the ONLY choice for a wide variety of specialized
applications requiring low power, high noise immunity, and so on.  It was
also extremely simple to apply.  In general, a "technology to fit the times" -
also, the only processor with a SEX instruction ("SEt X", yes it's true :-).

-- 
Jeff Berkowitz N6QOM			{sun,tektronix}!sequent!jjb
Sequent Computer Systems		Custom Systems Group
15450 SW Koll Pkwy			Home (503)629-0806
Beaverton OR 97006			Work (503)526-4148