Warning
It is not tuned. The frequency is close, but not qutie correct.
Create a virtual oscillator in Atmega32.
Other than the neccesarry instructions for reading keypad, showing LCD or PWM; We go through a "Delay" subroutine in order to achieve the desired frequency in PWM. inside the main "Delay" there exists 4 "sub-delays"; based on the given frequency(on the keypad) code goes through one of delays.