void init_port(void);
char clock_number(int);
void digit_1(int);
void digit_2(int);
void digit_3(int);
void digit_4(int); 
void clr_digit(void);
void A4_digit_clock(void);
void increment_hr_mint(void);
void hr_mint_write(void);

volatile char *outf = (volatile char *) 0x31;
volatile char *outk = (volatile char *) 0x108; 
volatile char *outb = (volatile char *) 0x25;
volatile char *ina = (volatile char *) 0x20;
  int hr1, hr2, mint1, mint2;
  int hr = 00, mint = 00, sec = 00;

void setup() 
{
  init_port();
  init_timer();


  // put your setup code here, to run once:
}
void init_port(void)
{
 volatile char *dirf = (volatile char *) 0x30;
 volatile char *dirk = (volatile char *) 0x107;
 volatile char *dirb = (volatile char *) 0x24;
 volatile char *dira = (volatile char *) 0x21;
 *dirb = 0x01;
 *dira = 0x00;
 *dirf = 0xff;
 *dirk = 0x0f;
}
void init_timer(void)
{
  volatile char *timer1_TCCR1A = (volatile char *)0X80;
  volatile char *timer1_TCCR1B = (volatile char *)0x81;
  volatile short *timer1_TCNT1 = (volatile short *)0x84;
  volatile short *timer1_OCR1A = (volatile short *)0x88;
  volatile char *timer1_TIMSK1 = (volatile char *)0x6F;


  *timer1_TCCR1A = 0;
  *timer1_TCCR1B = 0;
  *timer1_TCNT1 = 0;

  *timer1_OCR1A = 15800;
  *timer1_TCCR1B = 0x0d;
  *timer1_TIMSK1 = 0x02;
}
 char clock_number(int x)
{
  char outf [10] = {0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f};
  char out = outf[x];
  return out;
}
void digit_1(int y)
{
  *outf = clock_number(y);
  *outk = 0x0e;
}

void digit_2(int y)
{
  *outf = clock_number(y);
  *outk = 0x0d;
}
void digit_3(int y)
{
  *outf = clock_number(y);
  *outk = 0x0b;
}
void digit_4(int y)
{
  *outf = clock_number(y);
  *outk = 0x07;
}
void clr_digit(void)
{
  *outf = 0x00;
  *outk = 0xff;
} 
void A4_digit_clock(void)
{
  digit_1(hr1);
  clr_digit();
  digit_2(hr2);
  clr_digit();
  digit_3(mint1);
  clr_digit();
  digit_4(mint2);
  clr_digit();
}
void increment_hr_mint(void)
{
  if((*ina & 0x01) == 0x01)
  {
    delay(250);
    hr++;
    if (hr>23)
    {
      hr = 00;
    }
  }
  else if ((*ina & 0x02) == 0x02)
  {
    delay(250);
    mint++;
    if (mint>59)
    {
      mint = 00; 
    }
  }
  hr_mint_write();
}
void alarm(void)
{
  if((*ina & 0x04) == 0x04)
  {
    
  }
  
}
void hr_mint_write(void)
{
  hr1 = hr/10;
  hr2 = hr%10;
  mint1 = mint/10;
  mint2 = mint%10;
}
ISR(TIMER1_COMPA_vect)
{
  *outb = *outb ^ 0x01;
  sec++;
  if(sec >59)
  {
    mint++;
    if (mint > 59)
    {
      hr++;
      if(hr > 23)
      {
        hr = 00;
      }
      mint = 00;
    }
    sec = 00;
  }
hr_mint_write();
}
void loop() 
{
  increment_hr_mint();
  A4_digit_clock();
}