measuring time period

hI,
I want to code 89c51 for frequency measurement.
I am feeding the signal to interuppt & start the timer & counter after 1 sec i will stop the timer so i will get the period of pulse.
can anyone there provide me the code Please its urgent

u can mail me the same at kdandavate@celetronix.com

why do u stop ur timer only after 1 second?
shouldnt u stop the timer on the falling edge of the pulse?