29 Jan
2010
29 Jan
'10
12:50 p.m.
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.
The curious Tiger used a 68B09 for I/O (along with a Z80A for the main
processor and a 7220 graphics chip).
There were, of course, various special-purpose embeeded 6809 controller
boards.
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. 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. I still think the 6502 was cheaper than the 6800. I
think the 6502
was ~$50 when it came out compared to ~$250 of the 8080A and 6800.
That's almost certainly true. The 6502 was a cheap processor when it
first came out, But by about 1980 the other chips had really dropped in
price.
-tony