RtcController.h

#include "Wire.h"
#define DS3231_I2C_ADDRESS 0x68

class RtcController {
  public:
    RtcController() {
      Wire.begin();
    }
  void setTime(byte second, byte minute, byte hour, byte dayOfWeek, byte dayOfMonth, byte month, byte year) {
    // sets time and date data to DS3231
    Wire.beginTransmission(DS3231_I2C_ADDRESS);
    Wire.write(0); // set next input to start at the seconds register
    Wire.write(decToBcd(second)); // set seconds
    Wire.write(decToBcd(minute)); // set minutes
    Wire.write(decToBcd(hour)); // set hours
    Wire.write(decToBcd(dayOfWeek)); // set day of week (1=Sunday, 7=Saturday)
    Wire.write(decToBcd(dayOfMonth)); // set date (1 to 31)
    Wire.write(decToBcd(month)); // set month
    Wire.write(decToBcd(year)); // set year (0 to 99)
    Wire.endTransmission();
  }
  byte getSecond( void ) {
    byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
    this->readTime(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year);
    return second;
  }
  byte getMinute( void ) {
    byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
    this->readTime(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year);
    return minute;
  }
  byte getHour( void ) {
    byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
    this->readTime(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year);
    return hour;
  }
  
  private:
     // Convert normal decimal numbers to binary coded decimal
      byte decToBcd(byte val)
      {
        return( (val/10*16) + (val%10) );
      }
      // Convert binary coded decimal to normal decimal numbers
      byte bcdToDec(byte val)
      {
        return( (val/16*10) + (val%16) );
      }
      void readTime(byte *second, byte *minute, byte *hour, byte *dayOfWeek, byte *dayOfMonth, byte *month, byte *year)
      {
        Wire.beginTransmission(DS3231_I2C_ADDRESS);
        Wire.write(0); // set DS3231 register pointer to 00h
        Wire.endTransmission();
        Wire.requestFrom(DS3231_I2C_ADDRESS, 7);
        // request seven bytes of data from DS3231 starting from register 00h
        *second = bcdToDec(Wire.read() & 0x7f);
        *minute = bcdToDec(Wire.read());
        *hour = bcdToDec(Wire.read() & 0x3f);
        *dayOfWeek = bcdToDec(Wire.read());
        *dayOfMonth = bcdToDec(Wire.read());
        *month = bcdToDec(Wire.read());
        *year = bcdToDec(Wire.read());
      }
}; //end rtc Controller