//#include "suryaa.h"
#include <avr/interrupt.h>

void pin_configure(void)
{
  volatile char *dirf,*dirb;
 
  dirf=(volatile char*)0x30;
  dirb=(volatile char*)0x24;

  *dirf=0xFF;
  *dirb=0xFF;
}

void set_external_int_0(void)
{
  volatile char*eicr0a,*eimsk0;
  eicr0a=0x69;
  eimsk0=0X3D;

  *eicr0a=0x03;
  *eimsk0=0x01;
}

void output_pwm(int x)
{
  volatile char *ocr0a;
  ocr0a=(volatile char *)0x47;
  *ocr0a=x;
}


void delay_1(int x)
{
  volatile long i;
  while(x)
  {
    for(i=0;i<1000;i++);
    x--;
  }
}


void set_timer(void) //8 bit timer.
{
  volatile char*tccr0a,*tccr0b;   //setings of timer coontrol registers 
  tccr0a=(volatile char*)0x44;
  tccr0b=(volatile char*)0x45;

  *tccr0a=0x83; //set fastpwm non inverted mode;
  *tccr0b=0x03; //setting prescalar clock 64;
  
}

ISR(INT0_vect)
{
  volatile char*eifr;
  eifr=(volatile char*)0x3C;
  volatile long k;
  for(k=0;k<200000;k++);
  *eifr=0x01;
  volatile static long i=0;
  volatile char*outf=0x31;
  if(i!=8)
  {
    *outf=(1<<i);
    i++;
  }
  else
  {
    *outf=(1<<i);
    i=0;
  }
 // sei();
}
void setup() 
{
  pin_configure();
  set_external_int_0();
  set_timer();

  sei();
}



void loop()
{
  volatile int i,j;
  for(i=0;i<255;i++)
  {
    output_pwm(i);
    delay_1(1);
  }

  for(j=255;j>=0;j--)
  {
    output_pwm(j);
    delay_1(1);
  }
}