Actually My 99/4a has the 10.7 and the actual CPU is
clocked off the
slower division of that. The clocks you note were used for the video timing.
I'm quite sure this is backwards. According to my notes, the 99/4A uses a
12MHz oscillator divided down for its CPU, and uses a 10.7MHz clock divided
down for video (both, IIRC, by four). This page concurs (in French):
http://perso.orange.fr/fabrice.montupet/ticm.htm
However, the 9985 was a far nwer chip that the 9900
and was clocked
internally faster.
Quite, but the point I was making was that I don't believe the eight-bit
data bus muxing in the 99/4A was the primary reason performance was
comparatively poor.
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Cameron Kaiser * Floodgap Systems *
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