I planned to give 3phase voltage to ADC of PIC 16F877a micro controller , for doing this i have done the voltage divider network and i have tapped 5v AC using each phase step dwon transformer for 5 volts with DC values to PIC ADC chip its not supporting different phase but its supporting individual phase how to common to thesethree phase voltage please let me know you have done the same project please send the circuits how to convert analog to digital in a single chip