Path: utzoo!attcan!uunet!tektronix!reed!percival!nerd
From: nerd@percival.UUCP (Michael Galassi)
Newsgroups: comp.sys.m68k
Subject: Re: opcode emulation (Was: Re: 68020 in a *68010* socket?)
Message-ID: <1267@percival.UUCP>
Date: 15 Jun 88 02:37:29 GMT
References: <17206@gatech.edu> <10123@mcdchg.UUCP> <17479@glacier.STANFORD.EDU> <6276@cup.portal.com> <17482@glacier.STANFORD.EDU> <182@elgar.UUCP> <3447@pdn.UUCP>
Reply-To: nerd@percival.UUCP (Michael Galassi)
Organization: Percy's UNIX, Portland, OR.
Lines: 37

In article <3447@pdn.UUCP> alan@pdn.UUCP (0000-Alan Lovejoy) writes:

[ommited other points on which I have no comments and which do not
	realy pertain to the mc68012]

>Howerver, there is the mc68012, which if I remember correctly is
>completely software compatible with the 68020 but pin-compatible with
>the 68010.  But my memory is rather vague on this part.  Perhaps someone
>else has more authoritative info?

In software the mc68012 is almost identical to the mc68010, the diferences
occur in hardware, the 012 has aditional address pins a25-a29 and a31,
additionaly there are a couple of additional ground pins to support the
additional current sink from the wider address bus, and there is a
RMC\ pin which is active during a read/write/modify cycle intended for
buss locking purposes (semaphore updating etc...).

This info is gleamed from "mc68010/mc68012 16-/32-bit virtual memory
microprocessors" printed by Motorola in May, '85, this document is
labeled as "Advance Information" so may be inacurate or incomplete.

Personaly I have never seen the 012 and do not recal even reading
of any products using it.  Maybe the 012 never made it out of sample
phase?  I also checked the fourth edition of the MC68000's programmer's
ref. manual which also covers the 010 and 008 but found no reference
to the 012 (not even mention that it is/isn't identical to some other
part).

I may very well be wrong in some or all of what I say, if this is the
case I would apreciate someone correcting me.  Spelling errors along
with any other errors are my own.

-michael
-- 
        Michael Galassi           | If my opinions happen to be the same as
...!tektronix!tessi!percival!nerd | my employer's it is ONLY a coincidence,
...!uunet!littlei!percival!nerd   | of course coincidences DO happen.