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Forum Index : Microcontroller and PC projects : Read PWM duration

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cwilt
Senior Member

Joined: 20/03/2012
Location: United States
Posts: 147
Posted: 03:39pm 29 Apr 2012
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I have a need to read the duration of a PWM pulse. I tried using Setpin pin, 4 for period measurement but no luck. My next idea is to use 2 interupts. One for rising edge, the other for falling, and record the time between.

Any better ideas?
 
vk4tec

Senior Member

Joined: 24/03/2012
Location: Australia
Posts: 239
Posted: 11:32am 30 Apr 2012
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I know how to do it in Assembly Language

You wait for a rise ( or fall ) and then start a counter.

You wait for a rise ( or fall ) and then stop a counter.

Based on clock speed and instruction cycles, I then know.

And XTAL freq .

- Andrew -
Andrew Rich VK4TEC
www.tech-software.net
 
cwilt
Senior Member

Joined: 20/03/2012
Location: United States
Posts: 147
Posted: 09:10pm 30 Apr 2012
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Andrew,

I assumed that is what the duration setting is for setpin, but it always seems to return 0. I am using 2 xbee's to do IO pass through. Analog in on the remote produces a PWM output on the local xbee. Duration varies with voltage on the remote pin.

I have not found any example code using the duration setting. Perhaps I am not doing it in the proper order.Edited by cwilt 2012-05-02
 
bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2946
Posted: 10:01pm 30 Apr 2012
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  cwilt said   I have a need to read the duration of a PWM pulse. I tried using Setpin pin, 4 for period measurement but no luck. My next idea is to use 2 interupts. One for rising edge, the other for falling, and record the time between.

Any better ideas?


Gday Cwilt,

How small is the smallest expected pulse likely to be? That might help in assisting your answer..

Also is the pulse likely to repeat often etc? (I assume it would)

Regards,

Mick
Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<
 
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