Tony Duell wrote:
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.
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.
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.
-tony
Ben.