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256Re: using continuousrotationservo to control an esc

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  • RidgeSoft
    Mar 31, 2008
    • 0 Attachment
      William,

      It's preemptive. All you need to do is give the thread higher priority.

      It isn't a simple matter to expose the lower level servo PWM control.
      The eight servos are multiplexed off of a single output, which makes it
      tightly coupled to the hardware.

      Regards,

      RidgeSoft Support


      --- In intellibrain@yahoogroups.com, "William J. Rust" <wjr@...> wrote:
      >
      > I tried using Servo directly and it didn't work. However, using a
      pulse
      > output port does work. I got the motors to turn both ways. I should
      know
      > this but is the threading preemptive or will I need to put in yields
      to
      > make sure the motors keep running?
      >
      > BTW, when I decompiled the jar, I notice the servos are native calls.
      > Any chance that the parameters to the PWM call are, or could be,
      public?
      >
      > Thanks,
      >
      > wjr
      >
      > RidgeSoft wrote:
      > >
      > >
      > > Hi William,
      > >
      > > You might try using the Servo interface directly, rather than the
      > > ContinuousRotationServo facade. This will allow you to experiment
      with
      > > various pulse widths to see how the ESC responds. Another option is
      to
      > > use one of the pulse output ports. These have more flexibility in
      terms
      > > of pulse duration and frequency. To create a pulse train similar to
      > > what the servo ports do, you would have to have a high priority
      thread
      > > wake up every so often to fire a pulse on the port.
      > >
      > > Regards,
      > >
      > > RidgeSoft Support
      > >
      > > --- In intellibrain@yahoogroups.com
      > > <mailto:intellibrain%40yahoogroups.com>, "William J. Rust" wjr@
      > > wrote:
      > > >
      > > > Hi,
      > > >
      > > > I've finally gotten back to using my IB to control a TA RC car.
      The
      > > > problem that I am having is that it won't go into reverse. When I
      use
      > > > the RC controller, I have to flip it into reverse twice before it
      > > > actually takes but I believe that to be an artifact of the
      controller
      > > > instead of the esc. In any case, I recently got a javelin stamp
      and
      > > used
      > > > its servo port to make it go both forward and reverse. When I
      hooked
      > > up
      > > > both the IB and the JS to a 'sillicope, I found that the IB has a
      > > > slightly shorter period than the JS. This might mean that the esc
      sees
      > > > the pulse as being longer than it really is. When I shortened the
      > > pulse
      > > > times on the JS, it acted just like the IB does, not going into
      > > reverse.
      > > > The JS gives you really nuts and bolts access to the servo pwm. Is
      > > there
      > > > somewhere in the servo code that lets you do the same thing?
      > > >
      > > > Thanks,
      > > >
      > > > wjr
      > > >
      > > > --
      > > > William J. Rust, PhD
      > > >
      > >
      > >
      >
      >
      > --
      > William J. Rust, PhD
      >
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