Sorry about not clarifying the specs: Yes, the program complies and the time i m looking is about a second and i m using the 5 volts source in the arduino board to triggered the input capture. I tried to verify if i am even getting to the ISR by having the program to turn on and off led when it reached ISR, but it doesnt seem to do that, which made me thinkg that i m not even getting to ISR.I was getting the counter to count yesterday, but it was randomly triggering the event without any input to the capture pin. I m getting multiples results when tried triggering just one event, which i really dont understand. do i need to use the pull up resistor? I have verified my setup many times and read the user manual plenty. Your help is appreciated. Thank you