servo motor drive c programme code

#include <avr/io.h>
#include <util/delay.h>


void main()
{
 DDRA=0X00;

  unsigned char i,x,temp,y;  
  
   //Configure TIMER1
   TCCR1A|=(1<<COM1A1)|(1<<COM1B1)|(1<<WGM11);          //NON Inverted PWM
   TCCR1B|=(1<<WGM13)|(1<<WGM12)|(0<<CS11)|(1<<CS10);   //PRESCALER=1 MODE 14(FAST PWM)

   ICR1=19999;   //fPWM=50Hz (Period = 20ms Standard).

   DDRD|=(1<<PD4)|(1<<PD5);   //PWM Pins as Out

   while(1)
   {

      
       x=PINA&0b00001111;

if(x==0b00001111)
      
 {
   OCR1A=600;   //45 degree
      _delay_ms(200);
  }

      OCR1A=1050;   //90 degree
      _delay_ms(200);

      OCR1A=1950;   //135 degree
      _delay_ms(200);

      OCR1A=2400;   //180 degree
      _delay_ms(200);
	   OCR1A=600;   //45 degree
      _delay_ms(200);

      OCR1A=1050;   //90 degree
      _delay_ms(200);

      OCR1A=1950;   //135 degree
      _delay_ms(200);

      OCR1A=2400;   //180 degree
      _delay_ms(200);
	    OCR1A=1950;   //135 degree
      _delay_ms(200);

   }
}