Date   : Fri, 11 Sep 1987 11:49:10 GMT
From   : swrinde!petro!ssbn!bill@im4u.utexas.edu (Bill Kennedy)
Subject: Re: S100 68000 hardware

In article <KPETERSEN.12333367530.BABYL@SIMTEL20.ARPA> kenw@noah.arc.CDN
(Ken Wallewein) writes:

[abbreviating my reply]
>>contained 68008 coprocessor from Peak Electronics in San Jose for around

>  Interesting. I jut started getting MSJ. I'll check it out. But what
>does "bus rights" mean? Is there an interface? An S100 slot?

Bus rights means that the 68008 has access to everything on the bus,
memory and I/O.  The S-100 memory is accessed in pages that are set up
with a parallel port that is private to the 68K.  Also note that the
68008 had an 8 bit data bus and can only address 1Mb of memory.  That
limitation was not made by the board designer it's in the chip.  The
Godbout/CompuPro/Viasyn board is a real 68000, the aircraft carrier style
chip, the 68008 is in a 48 pin(?) DIP.  The CompuPro doesn't have any
on-board memory or peripherals so it's pretty hard to turn it on and off.

>  And I'm beginning to wonder what's so special about CP/M-68K. As far
>as I can see, it's not compatible with all my CP/M-80 stuff... what do
>you use it for?

Au contraire, the way the CP/M-68K BIOS is written you start it from CP/M-80
and it uses your CP/M-80 files (same goes for CP/M-86 and CP/M-816, the way
I use it) and BIOS.  That means that you are in the air in the time it takes
to type "CPM68K".  More importantly you can use all of your favorite stuff
(like an editor!) to compose stuff for CP/M-68K and then fire up the 68K to
run the C compiler and utilities.  I use it for "cross development", the
quotes mean that the target machine isn't emulated, it's really there.  I
have a dual processor (8085/8088) that runs CP/M-816 (80 and 86 transparently)
and when I need to run something for the 68K, I use the Peak board.  There
are a number of applications, print buffer, comm front end...  It's kind of
an expensive print buffer, but I got it because it was the least expensive
way I could tiptoe into the 68K world keeping my investment in S-100 assets
and development tools.
-- 
Bill Kennedy  {cbosgd | ihnp4!petro | sun!texsun!rrm}!ssbn!bill