SoftwareServo::refresh() -- how often really?

Forum 2005-2010 (read only) Hardware Interfacing
#1

Greetings. I’m writing some code to control a servo, and because the SoftwareServo documentation said that you have to call ::refresh() at least every 10ms, I made my code diligently call ::refresh() a number of times every 1ms after calling servo.write():

            g_servo.write(0);

                // ... do some stuff that probably takes < 10ms . . .

            // Wait 500ms to make sure servo reaches location
            for (int i = 0; i < 50; i++) {
                  SoftwareServo::refresh();
                  delay(10);
            }

Is this really necessary, as the documentation indicates? Or do you only have to call refresh() once about 20ms after each call to write(), like some sample code seems to do? :-/

Any help, or pointing to informative resources, is greatly appreciated.

#2

What library are you using?

http://arduino.cc/en/Reference/Servo

There is nothing about refresh in the Servo docs I have read. Where are you seeing that you have to call refresh?

#3

r/c frame rates are usually 50Hz, so at least every 20ms. Any reason for using this library, and not the hardware based ones?

#4

Oh, interesting. I googled “Arduino Servo” and got the SoftwareServo library here: http://www.arduino.cc/playground/ComponentLib/Servo , but apparently the ‘standard’ servo lib is the one you linked to which is “Servo.h”, ay. Thanks for the clear-up. :slight_smile:

The other library has the methods setMinimumPulse() and setMaximumPulse() for setting up the particular servo’s specifications; does Servo.h have something like that, so that you don’t overshoot the pulse range with write(degrees)? Edit: nevermind, I found it in attach(pin, min, max) :smiley:

#5