1 Feb
2010
1 Feb
'10
5:32 a.m.
Tony Duell wrote:
No... I spent many a year searching, too. I have the manual, which I think
includes the schematic (if not, I got that separately), but I never did come
across the physical board.
I'm not sure. The Beeb was 1982 or so. I thought the 6809 was out by
then. If not, it implies Acorn were still working on their System
machines, which seems a little curious.
I'm not sure quite when Acorn sold the rights to the System range to Control
Universal, but 1984 sticks in my head for some reason. If so, it implies that
in 1982 they still thought there was some mileage left in the System hardware.
I suppose that at the very least there were still quite a few System-based
fileservers around.
Remember that there was a *lot* of in-house expertise in 6502 development; the
Atom was almost a "System rack in a home computer box", just as the BBC was an
"Atom on steroids". I'm sure they considered other CPUs, but it made sense
to
stick with what they knew.
cheers
Jules
Tony Duell
wrote:
Around here, it was Apple
]['s and C-64's. The Coco was the only cost
6809 machine I can think of, but RS designed for BASIC rather than
business machine. RS did have a 68000 machine, but I think the next year
they switched to in house PC clones.
The only common 6809 machine in the UK was the Dragon, which was based
on the same Motorola application note as the CoCo. Of cource the CoCo was
also sold here (althohgh AFAIK the CoCo3 never was).
Acorn made a 6809 CPU board for their Eurocard based System machines, it
normally ran Flex09. It's not easy to find. Having
learned assembly language programming on the beautifully
simple architecture and instruction set of the 6800, the Byte magazine
article linked to below that I read when it was originally published
really impressed me. In the 6809 they made one of the earliest efforts
I know of to really tweak an already great uP instruction set based upon
an analysis of existing software:
I found the 6809 to be by far the nicest 8-bit
CPU I ever worked with.
The instruction set was simple and very orthogonal, the fact that you had
various relative addressing modes meant you could write truely
position-independant code, there were 2 stack points, and so on. Unlike
certain chips I could name, there were no major misfeatures that I came
across.
Of course the problem (as we all know) is that it came out too late. By
that tine everybody was using the Z80 or 6502. Oh well. The curious Tiger used a 68B09 for I/O (along with a
Z80A for the main
processor and a 7220 graphics chip).
The HH machine? I've never seen a real one, but it sounded like an interesting
beast.
There were, of course, various special-purpose
embeeded 6809 controller
boards.
I do have a Control Universal 6809 board (I don't recall if it's System bus or
STE now), so making that 'do' something is a possibility one day.
I pulled a whole stack of 6809s off some scrap telephone exchange boards many
years ago. I'm not sure whose product it was - AFAIK BT never used an exchange
which had 6809s, so it must have been some kind of private branch exchange.
It always suprised me that hre BBC micro used the 6502
rather than the
6809. By the time the Beeb was designed, Acorn had made a 6809 processor
board for their System machines, so they must have had experience with
the chip. THe Beeb is nice, but a Beeb with a 6809 processor would have
been something else :-)
I thought the BBC micro was designed, just before the 6809
came out.