I need help in power factor meter project

Hi, I asked for power factor meter project . I searched and found that I can use zero crossing detector circuit so I will use two zero crossing detector circuit one for current signal and the other for voltage signal my question here I need help in the code for Atmega32 when Atmega32 detect the pulse for voltage zero crossing detector circuit start counting and when detect the pulse for current zero crossing detector circuit stop counting and so i can convert the countering result into degree to find power factor can someone help me to perform this in micro c compiler