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PaulStoffregen / FreqCount

Measures the frequency of a signal by counting the number of pulses during a fixed time.
http://www.pjrc.com/teensy/td_libs_FreqCount.html
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Freq count t4 branch #11

Closed mjs513 closed 5 years ago

mjs513 commented 5 years ago

I modified FreqCount library to use GPT2 and intervaltimer on pin 14 of the T4, see post post #3790 and post #3792. The changes were based on @manitous original post #982.

Just not sure the max freq it can measure, think the manual said 1/4 ipg clock but really don't have anything I can use to test that.

mjs513 commented 5 years ago

Paul I did run some tests but seems funny when I tried to get up to the higher frequencies. I put the QT3 timer code to generate the signal on one T4 and used a second T4beta board to run example sketches from the freqcount and FreqMeasure libs. Looks like I can get a max of 10Mhz with FreqCount and 5Mhz with FreqMeasure. Seems funny. I don't have a frequency generator to do any further testing.

mjs513 commented 5 years ago

Paul - talking to manitou on the T4 thread we were able to get it up to 30Mhz but as @manitou pointed out in post #3289 it would cause other issues so i reverted all the changes back. There will just be a 10Mhz limit for the T4

mjs513 commented 5 years ago

Paul - know you are busy but going to go ahead and close this we are still working it on the forum. Hoping someone with a frequency generator can test it for us before we post the next set of changes.