[Coco] 6x09 instruction timings

[jdaggett at gate.net]

On 20 Jan 2007 at 17:01, Joel Ewy wrote:

> Ok, stupid question.
> 
> I know that the Q clock and the E clock are 180 degrees out of phase,
> and that the CPU uses this relationship to separately clock different
> internal states.  But when reading instruction set timings, a cycle is
> one complete cycle of the E clock, without respect to what Q is doing
> (though their period is the same), is that correct?  So at 1.78 MHz, 1
> cycle of the E clock is a little more than .56 microseconds, if I
> understand this correctly.
> 
***********
In the MC6809/HD6309 the E clock period is the determination for cycle time. At High speed 
the Coco's have a cycle time of 579 nanoSec. The Q clock is phased shifted by 90degrees 
and leads the E clock by that phase. The Q clock is used internally to gate sychronous 
operation fo the internal logic for the MC6809 and probably for gating some ot the 
microcode states within the HD6309.  

james
> Just looking at Sockmaster's Hicolor code and thinking about how much
> processing could be done during the scan lines, vertical blanking,
> etc.
> 
> JCE
> 
> 
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