Jean-Francois wrote:

>I have a few questions concerning servos & pic16c84 microcontrollers...
>
>        1) How do I interface a servo with the pic16c84? Can it be directly
>        connected to one of the microcontroller`s output pin? Will the chip
>        supply enought power to make it run?

Servos typically have three lines, Control, Gnd, & Vcc (in that order).  The
Servo Control can be hooked up directly to a PIC.  The signal itself repeats
every 20 msec and consists of a Vcc Pulse 1 to 2 msec in length.

The PIC can't supply enough current to power the Servo.

>        2) Concerning the software; how can I generate a pulse width of
>        about 0.00075 to 0.00225 second to control the servo`s position?

I use the TMR0 Interrupt; every 18 msec, I put out a 1 msec pulse and then
set a counter that makes the pulse low when the value equals the counter.
The Counter goes on until another 1 msec is used up.

With this method, you can control multiple servos very easily.

>        3) Anyone knows a good, low cost, high torque servo that would be
>        good for little robots and things like that?

I bought Tower Hobbies "TS-51" Servos for $11.95 (USD).  They have others
that have more capabilities (and higher cost).  Note that Futaba Servos
require a different timing spec.

Their web page is "http://www.towerhobbies.com".

Good luck!

myke
>
>Thank you!
>Jean-Francois
>-----------
>Jean-Francois & Alain Joly
>jolyal@capitalnet.com
>
>

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