TI 990 architecture

[Cameron Kaiser]

> 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 * www.floodgap.com * ckaiser at floodgap.com
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