How to?????? >> square wave inverter. Feedback option needed

Hi,
I design a Full bride Inverter. But I want to add feedback option to my project. I got 50Hz freq from my full bridge.
plz anyone help me!!!!!!!!!! How I add feedback to my project??????

Code:

DEFINE OSC 16 ON INTERRUPT GOTO UPDATE DIR VAR BYTE '************************* Assign some Interrupt associated aliases T0IE VAR INTCON.5 ' TMR0 Overflow Interrupt Enable T0IF VAR INTCON.2 ' TMR0 Overflow Interrupt Flag GIE VAR INTCON.7 ' Global Interrupt Enable PS0 VAR OPTION_REG.0 ' Prescaler ratio bit-0 PS1 VAR OPTION_REG.1 ' Prescaler ratio bit-1 PS2 VAR OPTION_REG.2 ' Prescaler ratio bit-2 PSA VAR OPTION_REG.3 ' Prescaler Assignment (1=assigned to WDT 0=assigned to oscillator) T0CS VAR OPTION_REG.5 ' Timer0 Clock Source Select (0=Internal clock 1=External PORTA.4) PWM1 VAR PORTC.5 ' Alias servo pin1 PWM2 VAR PORTC.6 ' Alias servo pin2 TRISC = 000000 ' Configure PORTC as outputs PORTC = 0 ' Clear PORTB '********************* Initiate the interrupt GIE = 0 ' Turn off global interrupts PSA = 0 ' Assign the prescaler to external oscillator PS0 = 1 ' Set the prescaler PS1 = 1 ' to increment TMR0 PS2 = 1 ' every 256th instruction cycle T0CS = 0 ' Assign TMR0 clock to internal source TMR0 = 0 ' Clear TMR0 initially T0IE = 1 ' Enable TMR0 overflow interrupt GIE = 1 ' Enable global interrupts MAIN: GOTO MAIN DISABLE UPDATE: TMR0 = 100 IF DIR = 0 THEN PWM1 = 1 PWM2 = 0 DIR = 1 ELSE PWM2 = 1 PWM1 = 0 DIR = 0 ENDIF T0IF = 0 RESUME ENABLE