function pulseIn(pin, value, timeout) doesn't work?

Development Libraries
#1

I use ultrasonic to measure the distance.

  1. pulseIn(pin, value) - working, but not as documentation describe it: timeout "default is one second"

I have only 450 us pause to start capture the pulse.

  1. pulseIn(pin, value, timeout) - returns 0 with any value of timeout
#2

please post your code and schematic.

what board are you using?
which version of the IDE?

  1. timeout does not have a default value,

PulseIn() is a less accurate functions:

  1. timeout is in microseconds and INCLUDES the waiting time before the pulse
  2. different versions of the compiler optimizes the code differently causing up to 15% deviation
  3. it contains hard coded magic numbers e.g. 16 for clock which is not always true.

Think the pulseIn() code is reasonably valid for 16MHZ UNO and MEGA but not for ARM

#3