RTClib.h

// Code by JeeLabs http://news.jeelabs.org/code/
// Released to the public domain! Enjoy!

// Simple general-purpose date/time class (no TZ / DST / leap second handling!)
class DateTime {
public:
    DateTime (uint32_t t =0);
    DateTime (uint16_t year, uint8_t month, uint8_t day,
                uint8_t hour =0, uint8_t min =0, uint8_t sec =0);
    DateTime (const char* date, const char* time);
    uint16_t year() const       { return 2000 + yOff; }
    uint8_t month() const       { return m; }
    uint8_t day() const         { return d; }
    uint8_t hour() const        { return hh; }
    uint8_t minute() const      { return mm; }
    uint8_t second() const      { return ss; }
    uint8_t dayOfWeek() const;

    // 32-bit times as seconds since 1/1/2000
    long secondstime() const;   
    // 32-bit times as seconds since 1/1/1970
    uint32_t unixtime(void) const;

protected:
    uint8_t yOff, m, d, hh, mm, ss;
};

// RTC based on the DS1307 chip connected via I2C and the Wire library
enum Ds1307SqwPinMode { OFF = 0x00, ON = 0x80, SquareWave1HZ = 0x10, SquareWave4kHz = 0x11, SquareWave8kHz = 0x12, SquareWave32kHz = 0x13 };

class RTC_DS1307 {
public:
  static uint8_t begin(void);
    static void adjust(const DateTime& dt);
    uint8_t isrunning(void);
    static DateTime now();
    static uint8_t readMemory(uint8_t offset, uint8_t* data, uint8_t length);
    static uint8_t writeMemory(uint8_t offset, uint8_t* data, uint8_t length);
    static Ds1307SqwPinMode readSqwPinMode();
    static void writeSqwPinMode(Ds1307SqwPinMode mode);
};

// RTC using the internal millis() clock, has to be initialized before use
// NOTE: this clock won't be correct once the millis() timer rolls over (>49d?)
class RTC_Millis {
public:
    static void begin(const DateTime& dt) { adjust(dt); }
    static void adjust(const DateTime& dt);
    static DateTime now();

protected:
    static long offset;
};