AVR-Chat

There is no jitter between pulses as the timer match condition finishes one
pulse and starts the next. The processor has up to the minimum pulse width
to service the interrupt and set up the next match.

 

The only jitter would be the start of the pulse train and that would be
whatever jitter you have in your system time.  If, for example, you had a
1khz clock you could call "StartRCout()" from the interrupt handler every 24
ticks and have very low jitter.


But, besides that, Servos are pretty insensitive to the pulse repetition
rate.  Anything between 20-60hz would be fine.

 

 

-----------

Larry Barello

www.barello.net

 

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From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of Martin Jay McKee
Sent: Saturday, November 12, 2005 11:32 AM
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Servo Control Without PWM, Was: Phase and Frequency
Correct PWM on a Mega 8

 

>>Also if you want to see how to use that technique to get 8 r/c pulse
outputs from two pins, look at:

 

>>http://www.barello.net/Papers/AVR%20RC%20output.pdf

 

I saw this a while ago and I was meaning to ask (never got around to it) how
smoothly it works.  It seems that the time between pulses would vary
slightly and so allow for the possibility of jitter.  Has that shown up at
all in use?

 

Martin Jay McKee

 

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