1 Dec
2007
1 Dec
'07
4:10 p.m.
It was thus said that the Great John Honniball once stated:
Tony Duell wrote:
I seem to recall that the original Apple I had a jumper that selected
between a 6502 and a 6800. The ony reason that Apple used the 6502 was
price.
-spc (or so I've heard ... )
The 6809 and 6502 buses are _very_ similar (read
'E' for 'Phi2',
basically ;-)). Most I/O cards would work with either CPU (hence the lack
of problems in haveing a 6809 CPU in a System). Of course the
instruction set, and thus firmware/software are very different.
I've successfully installed a 6809 in a previously 6502-based
machine: the Compukit UK101. I had to write new EPROM-based
firmware for it, of course. As far as the bus and I/O devices
are concerned, it Just Works. Even the pinout is similar enough
that the socket adaptor is easy to build.