[Coco] Questions about the Coco3 GIME Timer

[Robert Gault]

Gene Heskett wrote:
><snip>
> Do you recall the tick resolution of this timer, John?  If its not in 16ms 
> increments, but finer, as in hsync or even Eclocks, this would be a great 
> way for George to get some higher speeds out of his coco while driving 
> the steppers.  But of course there is only one timer, and there are at 
> least 3 axis's to independently control.  So it looks as if that's ruled 
> out.  Darn.
> 
 ><snip>

Two speeds, either 279.4 nsec (1/8 crystal speed = color burst) or 63 
usec. The service manual is incorrect claiming 70 nsec for the fast speed.

  There is a limit to how fast you want the timer interrupt to function. 
It can easily exceed any program routine which is part of the IRQ or 
FIRQ routine and if that is true, the technique is useless as interrupts 
will be missed.
  Put another way, the Coco is not fast enough for many purposes even at 
2 MHz.