View Full Version : My new MoBo-Stamp-PE

01-29-2010, 04:50 AM
Hello Everyone!

I just recieved my new MoBo Stamp, this thing is great!

I understand that the ATtiny13's are capable of PWM on ports 2 and 3, at your choice of speed/duty cycle anywhere from 1/256 to 255/256.

I would like to use this function to pulse a Parallax continuos rotation servo, which responds to 1.5ms wide·pulses·to hold still,
1.3ms wide·full forward, 1.7ms wide·full reverse (or vise versa), at the maximum of 20ms between.

However, reading the GPIO manual on the MoBo page, I don't understand how to figure out the width of the pulses
from the ATtiny,·only the total frequency (given by the 0-255 data byte that one sends when telling it to start PWM)

Anyone know how I can figure out the Widths of the pulses sent by the ATtiny, depending on the Frequency/duty cycle I select,
or is this Function not designed for·pulsing servos?

I imagine the other way to figure it out would be to hook up my Pwr-i/o daughterboard, hook up the servo to port 2/3 of the
ATtiny, and experiment until i can find which duty cycle runs the servo full speed.

I'm just wondering if anyone else here has already been here, done this, and can offer me some guidance as to how they made it

Thank you very much·in advance for your help!!!


Phil Pilgrim (PhiPi)
01-29-2010, 05:38 AM

I'm glad you like the MoBo!

The AVR's PWM outputs are unsuitable for driving RC servos. However, I've posted a different AVR driver for servos here:


Give it a try. I hope it works for you!


01-29-2010, 06:36 AM
Thanks, Phil!

That is exactly what I need!

This will do Perfect.

Thanks again,