volatile int  count=255;
volatile char  *outF;
volatile char *dirF,*dirK,*inputK;

void setup() {
  // put your setup code here, to run once:
 outF=0x31;
 dirF=0X30; 
 *dirF=0x01;
 dirK=0x107;
 *dirK=0x00;
 inputK=0x106;
 init_timer1();
while(1){
  
  while (TCNT1<count){
    //pulse low
     *outF=0x00;
     increase();
     mydelay();
     decrease();
     mydelay();
  }
  while(TCNT1>count)
  {
    //pulse high
     *outF=0x01;
      increase();
      mydelay();
      decrease();
      mydelay();
  }
}
}

void loop() {
  // put your main code here, to run repeatedly:

}
void init_timer1(){
TCCR1A=0;
TCNT1=0;
TCCR1B=0;

OCR1A=0xFF; // maximum counter value
TCCR1B=0X0C;//Selecting  prescaller
TIMSK1=0X02;// enabling local interrupt

}
ISR(TIMER1_COMPA_vect){
  // count--;
  // if(count<0){
  //   count=255;
  // }
 
}

void increase()
{
if(*inputK==0x01)
  {
    
    count=count-1;
    if(count<0)
    {
      count=0;
    }
  }
}

void decrease()
{
  
  if(*inputK==0x02){
  
  count=count+1;
  
    if(count>255)
    {
      count=255;
    }
  }
}

void mydelay(){
  for(volatile int i=0;i<500;i++);
}