Date   : Fri, 15 Mar 2002 19:08:20 GMT
From   : pete@... (Pete Turnbull)
Subject: Re: Really trivial question...

On Mar 15, 17:16, Mike Tomlinson wrote:
> In article <INEBINJGPKFAHFODGMHCKEGICDAA.r.gellman@...>,
> Richard Gellman <r.gellman@...> writes
> >Does anyone have a definitive answer (if there is one) as to the
differences
> >between a 65C12 (Master 128) a 65C02 (BBC B Tube) and a 65C102 (M128
Tube) ?
>
> If you mean data sheets which list CPU instructions, no, but maybe it
> will be useful for you to know I plugged a 65C02 into a BBC B and this
> allowed me to run a BASIC 4 ROM image nicked from a Master.

You have to be *slightly* careful with that, as there are at least two
flavours of 65C02, with slight differences in the instruction set.  AFAIR
Rockwell ones are the ones that work, and the more common type.  The other
type is MOS Technology (there's also a Mitsubishi almost-65C02 but it has a
different type number and fewer instructions).  Both have bug-fixes
compared to the plain 6502 (eg the JMP (xxFF) bug), but there are some
minor differences in the extensions to the instruction set (more in the
Rockwell version).

65C02 is a CMOS (lower-power) version of an NMOS 6502; same pinout but
extended instruction set (you can do more load/store of X and Y directly,
for example).  It's also available in faster 3MHz and 4MHz versions.

65C12 is similar to 65C02 but slightly different pinout: different clock
arrangement.

I can't remember what's different about a 65C102, I'm afraid.  I know it
uses a 65C02 core, designed by Western Design Centre, and the subject of a
lawsuit by CBM.  It *might* just be a cheaper 65C02 (I'm pretty sure it's
the same pinout etc).


-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York