master

master_demo.cpp

/*skip those varible which i initailized*/
void loop()
{
  timeTracing();
}
void transmit(byte addr, byte something)
{
  Wire.beginTransmission(addr);
  Wire.write(something);
  Wire.endTransmission();
}

void timeTracing(void)
{
  timeNow = millis() / 1000;
  seconds = timeNow - timeLast;
  
  digits = seconds % 10;
  transmit(0x09, digits);//transmit the number which is just one byte each time 
  
  ten_digits = seconds / 10;
  transmit(0x08, ten_digits);
  
  if (seconds == 60)
  {
    timeLast = timeNow;
    minutes = minutes + 1;
    mins = minutes;
  }

  if (minutes == 60) 
  {
    minutes = 0;
    mins = minutes;
    hours = hours + 1;
    hrs = hours;
  }
  mins_digits = mins % 10;
  transmit(0x07, mins_digits);

  mins_ten_digits = mins / 10;
  transmit(0x06, mins_ten_digits);

  if (hours == 24) {
    hours = 0;
    hrs = hours;
    days = days + 1;
  } 
  
  hrs_digits = hrs % 10;
  transmit(0x05, hrs_digits);

  hrs_ten_digits = hrs / 10;
  transmit(0x04, hrs_ten_digits);
  /*
  there are still something below...skip!
  .
  .
  .
  */
}