> The Steering controllers have a different problem associated with
> them. They're quadrature-modulated pulses that require interrupts to work
> optimally. Sampling them doesn't work. They will likely not be supported
> in the future.
I have never bothered to take mine apart before(and I am away from them
for a while :( ), but now I'm curious about this.
Can anyone verify this?
Mark
BTW, a 'quadrature moduleated pulse' is the standard output of a 'digital'
pot, or a shaft encoder. It works in a very similar fashion as one of the
dimensions of a mouse. The jist is that you supply power and ground to
power some leds, and have 2 data lines coming back. If the shaft(knob)is
rotated at a constant velocity, the data coming back appears as 2 square
waves, one quarter period shifted. By analysing the frequency of the
square waves, and which one of the two is ahead of the other determines
the speed and direction the shaft is being rotated. This is kinda
simplified, but the non-technical readers should get the idea.
BBTW, as a side note, sampling/polling can work, it simply depends on how
fast the sampling is, and how fine the detents are on the knob.(I know, I
recently built a system that sampled instead of interupted(If you must
know why Chris... I wanted less hardware, as using interupts requires a
few ff's(or a controller chip), and I was using the interupt lines as CS
lines)) The detents can't be that fine because the atari obviously samples
it, and the atari is not known for fast response on polling it's inputs...
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