void PWM_Set_duty( uint16_t duty_cycle, uint16_t timer_prescalar )
{
     uint16_t reg_value;
     float frequency;
     frequency  = (_XTAL_FREQ/2);
     frequency  = (frequency/timer_prescalar);
     frequency  = (frequency/(PR2+1));             // FREQUENCY OF PWM SIGNAL

     frequency  = (frequency*100)/(duty_cycle);

     reg_value  = (_XTAL_FREQ)/(uint16_t)(frequency);
     reg_value  = (reg_value/timer_prescalar);
     OC1RS      =  reg_value;
     OC1R       =  OC1RS;   
}

PWM_Set_Duty.c:13:29: error: expected ')' before 'duty_cycle'

 

Hello....

An C compiler will produce 1,000 errors from an missing ; or } etc ... So your problem would be anything.

You need to step through the code to debug it...

 

actually am getting error in this function prototype... and am unable to solve this

void PWM_Set_duty( uint16_t duty_cycle, uint16_t timer_prescalar )

 

What't the relationship between (uint16_t) and (frequency) ?
Are you missing '*' or '/' or ... ?

reg_value = (_XTAL_FREQ)/(uint16_t)(frequency);

 

first i have initialized frequency as float type . then am doing type casting for frequency by changing into unsigned int and finally loading the value into reg_value

reg_value = (_XTAL_FREQ)/(uint16_t)(frequency);

 

void PWM_Set_duty(int uint16_t duty_cycle, int uint16_t timer_prescalar )

i cant declare this two integer outside the prototype because in the main programming i will be loading some values to this

 

void PWM_Set_duty( uint16_t duty_cycle, uint16_t timer_prescalar )

Try to delete two spaces in the brackets.
void PWM_Set_duty(uint16_t duty_cycle, uint16_t timer_prescalar)

 

i solved the problem ... i did not include that prototype function that was the error

 

As this?
void uint16_t PWM_Set_duty( uint16_t duty_cycle, uint16_t timer_prescalar )

 

void uint16_t PWM_Set_duty( uint16_t duty_cycle, uint16_t timer_prescalar );