arduino/Arduino — pull request #2446 by BrettAM (2014-11-17 04:44:30+00:00)
Title: Made Servo library output frequency no longer constant

The old "REFRESH_INTERVAL" has been changed to be settable
for better compatability with digital servos and ESC's

The defualt value of 20000 microseconds (50Hz) is maintained,
and a minimum of 3000 microseconds (333Hz) is imposed.

3000 microsecends was chosen because it allows for
MINIMUM_PULSE_WIDTH of time low after
MAXIMUM_PULSE_WIDTH of time high, rounded up by 56 us