No. The PWM for a servo is different than a continuous PWM signal needed for a regular motor. Hobby servos have their own electronics and only require a moderately frequent signal to keep the motor going. The signal, for most 90 degree motors, is between 1 ms and 2 ms with a gap of about 20 ms between updates. A signal of 1.5 ms will drive the servo to the middle position. The exact specs are just a little bit different for different servos. After updating the servo, there is a wait time before the next update of about (avg) 20 ms. That kind of a signal can be sent as part of the general chores of the checking sensors and outputting other information. For a good summary of how to command the servo, see http://www3.sympatico.com/donroy and look at the instructions for the 1stBot kit. Dan -----Original Message----- From: Mike M To: PICLIST@MITVMA.MIT.EDU Date: Thursday, November 18, 1999 6:17 AM Subject: [OT] Re: PWM background >How do basic stamps 1 or 2 run servo motors? Dont they use 16C56 that also does not have a pwm port??? > >On Wed, 17 Nov 1999 17:26:23 -0500 Sean Breheny wrote: >>At 08:55 AM 11/18/99 +1200, you wrote: >>>I haven't done this myself yet but I can't see why a PWM of lowish >>>freq and not too high a resolution couldn't be run from the timer >>>overflow interrupt. >> >> >>Yes, it certainly can be done. I did it in a robotics project. Take a look at: >> >>http://www.hobbyrobot.com/info/SoccerBot/index.html >> >>and specifically the PIC source code >> >>http://www.hobbyrobot.com/info/SoccerBot/code/bot11.asm >> >>It is true that I only achieved a PWM frequency of a few kHz at 7-bit >>resolution (I think the maximum possible rate for a 10MHz PIC was about >>10kHz for 8 bit resolution). >> >>Sean >> >> >>| >>| Sean Breheny >>| Amateur Radio Callsign: KA3YXM >>| Electrical Engineering Student >>\--------------=---------------- >>Save lives, please look at http://www.all.org >>Personal page: http://www.people.cornell.edu/pages/shb7 >>mailto:shb7@cornell.edu ICQ #: 3329174 >> > >Send someone a cool Dynamitemail flashcard greeting!! And get rewarded. >GO AHEAD! http://cards.dynamitemail.com/index.php3?rid=fc-41