C3-SI

From: Mike <dogas_at_bellsouth.net>
Date: Mon Jan 28 11:15:42 2002

From: Ethan Dicks <erd_6502_at_yahoo.com>

> >
> > > The C3 was kinda cool... It was wild to see a box with multiple
CPUs...
> >
> > C3's are cool... One, a C3-SI with a C2D dual 8" floppy system using
the
> > 530 board (I think) which has the z80, 6800, and 6502 all on board.

D'oh. That's a 510 board, not a 530

>
> That's the one! We had a family friend who put himself in serious hock
> for one of those when it was new.

me too, and for a used one. ;)

> > I wish I could find the OSI 460Z board... that adds the Intersil 6100
> > and some other microprocessor too to the base 3 of the C3.
>
> That sounds wicked. I wonder how they handled the 12-bit bus of the
> 6100.

pins 19-22 on the standard OSI bus = A16 - A19 for extended addressing under
the 6502 (multiuser and under software control of the PIA) and probably used
natively under the 6100...

> > (If they had just jammed the CDP1802 in there too I could have prossibly
> > settled on this one machine to collect...those bastards...)
>
> Agreed... you could have all the big stars of the 1970s micros in one
> cabinet. I still don't get how they managed all the different machines
> in one box. The easy part is building a CPU board where you can
disconnect
> a particular CPU from the bus in software. The hard part is the handoff.
> You'd almost need a way to preload RAM or select a ROM that was ready to
> go for the next CPU you wanted to switch to. It's been so long since I've
> used a C3 that I forget entirely how to boot it and switch it around. Are

It boots under one processor (hardware selected) usually 6502 on a reset
Software processor selects happens with a PIA port . Both the 6502 and 6800
reset and drop into their monitors, the z-80 just jumps to whatever address
is preloaded at address 0 so it could be somewhat used as a slave processor
without changes. the 6800 and 6502 could too but you did have to hack in
some relocatable RAM that responded to the PIA controlled processor
shifts...


> there any manuals online?

Haven't looked. Got two shelves full of dealer, software, and hardware docs
on OSI models 400 - C8P. So someday maybe when the time fairy leaves some
days under my pillow... until then, just ask.

;)
- Mike: dogas_at_bellsouth.net
Received on Mon Jan 28 2002 - 11:15:42 GMT