On 9/09/2011 11:45 AM, Josh Koffman wrote:
> I've spent a bunch of time searching but haven't found much that's=20
> enlightening. My problem with projects like the one you linked to is=20
> that because their only purpose is to drive the servo, they aren't=20
> written to do much else, and they don't take advantage of the=20
> peripherals present in the chip. I guess I'm being picky! I am going=20
> to try just writing my own, hopefully it won't go too badly :) Josh=20

Josh, the basic idea is:

Set up a free running 20ms timer on tmr0.

When tmr0 fires, set the first servo output high and set tmr1 to the=20
pulse width you want for servo 1.

When tmr1 fires, turn servo output 1 off, turn servo 2 output on and set=20
tmr1 to the pulse width you want for servo 2.

Repeat unitl all servos are serviced, then wait for the 20ms timer to=20
fire again.

This round robin works for up to 8 servos as 8 x 2ms =3D 16ms so you can=20
service them all within the 20ms.  The pulse positions move about=20
somewhat within each 20ms event, but the servos don't seem to mind.
David...

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___________________________________________
David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: www.audiovisualdevices.com.au
___________________________________________

--=20
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