Best way to measure period between pulses? Counters and FPGA

[jhersh]

Originally Posted by Ken Streeter

Below is the definition for the ShooterWheelTask, of which the "run" method will be executed every 20 milliseconds. This code computed the wheel RPM by dividing the number of counts observed since the last invocation by the elapsed time since the last invocation, with appropriate unit conversions.

This is "method 1" above. This is what he claims not to want.

Originally Posted by Ken Streeter

Time was measured using the FPGATimestamp, which has a resolution of approximately 6.5usec.

This is inaccurate. The FPGATimestamp itself has a resolution of 1 us. The digital I/O that it timestamps (in the case of digital interrupts or encoder pulse measurements, etc.) is 6.525 us.

Cheers,
-Joe