looking for the best way to measure freq DSPIC33EP512MU814

[ccsx3]

hi
i start a little project with DSPIC33EP512MU814.
and I'm looking for the best way to measure frequency
i tried to use the interrupt on setup_capture and count every rise edge
in one second.

and my results are not so good ...
the freq that i try to measure is between 0hz - 400hz

hope you have some ideas for me

[temtronic]

There is no 'best way' to measure frequency...
.. probably 15-20 factors will contribute to a 'good' way that works for you.

CCS does supply some 'example' code in the examples folder....
...might be a good place to start

also use the 'search' feature on this forum( takes some practice) or use Google to find a LOT of 'measure frequency' type code.

hth
jay

[PCM programmer]

There are several threads on frequency measurement for 16F and 18F:
http://www.ccsinfo.com/forum/viewtopic.php?t=29963
http://www.ccsinfo.com/forum/viewtopic.php?t=41172
http://www.ccsinfo.com/forum/viewtopic.php?t=33153

You would have to convert the method used in these threads
to use PCD-compatible functions. I can't easily do it because
I don't have the PCD compiler.

[Mike Walne]

For low frequencies you are usually better off measuring the period of one (or several) cycles, then doing the maths.

I showed a method for PIC16-18s some time ago which worked well for high frequencies.
The process was very portable, maybe you could modify it.

Mike