Quote:
Originally Posted by jhersh
That's not quite an accurate interpretation of my post. You can measure the frequency in any of the counter / encoder modes. The point I was trying to make was that the semi-period mode is pretty much useful only for timing.
From reading your application description, you probably want to use Up/Down counter mode, and only specify the "up source". When you read the timer output, it will be reporting the speed based on "method 2" that you described above.
Cheers
-Joe
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This is odd, because all weekend we were have major resolution problems.
We had a Counter set up exactly as you describe above. The periods we were getting had a very pronounced stepwise response. As a result, our RPM readings changed in increments of about 375 RPM.
We did the math, and these increments corresponded with 1 count / 20ms, which led us to believe the reads were still being done via method 1.
Very strange.
Is it possible that the other modes (other than semi-period) use the FPGA to count pulses over a 20ms period instead of measuring the time between pulses directly?
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