6 May
2010
6 May
'10
10:46 a.m.
On 5 May 2010 at 21:02, Tony Duell wrote:
I always felt that Motorola mis-specified the 6809 clock. They claimed it
was a 1MHz machine -- and that was the sped of the 2 bus clocks (E and
Q). But those clocks were derived from a 4* clock input -- in other words
4MHz for the maximum speed. Any other company would have called it a 4MHz
perocessor. Of course the Motorola way does have the advantage that the
6809E (which (where the clocks are produced externally, you have to feed
it a pair of 1MHz signals in pahse quadrature) is the same speed, but
marketroids don't think like that :-)
I sitll stand my my statement that the master
clock rate is
meaningless.
Reminds me of one of the comments by the 6809 development team when
criticized over the low 1MHz clock. One stated that if they had known that clock rates were that important, they would
have brought
it out with a waveguide clock input.
Similar ot my tongue-in-cheek 1GHz Z80A :-)
-tony