RTClib.cpp

// A library for handling real-time clocks, dates, etc.
// 2010-02-04 <jc@wippler.nl> http://opensource.org/licenses/mit-license.php

#include <Wire.h>
#include <avr/pgmspace.h>
#include "RTClib.h"
#include <Arduino.h>

#define DS1307_ADDRESS      0x68

#define PCF8563_ADDRESS     0x51
#define PCF8563_SEC_ADDR    0x02

#define SECONDS_PER_DAY     86400L

////////////////////////////////////////////////////////////////////////////////
// utility code, some of this could be exposed in the DateTime API if needed

static const uint8_t daysInMonth [] PROGMEM = {
  31,28,31,30,31,30,31,31,30,31,30,31
};

// number of days since 2000/01/01, valid for 2001..2099
static uint16_t date2days(uint16_t y, uint8_t m, uint8_t d) {
    if (y >= 2000)
        y -= 2000;
    uint16_t days = d;
    for (uint8_t i = 1; i < m; ++i)
        days += pgm_read_byte(daysInMonth + i - 1);
    if (m > 2 && y % 4 == 0)
        ++days;
    return days + 365 * y + (y + 3) / 4 - 1;
}

static long time2long(uint16_t days, uint8_t h, uint8_t m, uint8_t s) {
    return ((days * 24L + h) * 60 + m) * 60 + s;
}

////////////////////////////////////////////////////////////////////////////////
// DateTime implementation - ignores time zones and DST changes
// NOTE: also ignores leap seconds, see http://en.wikipedia.org/wiki/Leap_second

DateTime::DateTime (long t) {
    ss = t % 60;
    t /= 60;
    mm = t % 60;
    t /= 60;
    hh = t % 24;
    uint16_t days = t / 24;
    uint8_t leap;
    for (yOff = 0; ; ++yOff) {
        leap = yOff % 4 == 0;
        if (days < 365 + leap)
            break;
        days -= 365 + leap;
    }
    for (m = 1; ; ++m) {
        uint8_t daysPerMonth = pgm_read_byte(daysInMonth + m - 1);
        if (leap && m == 2)
            ++daysPerMonth;
        if (days < daysPerMonth)
            break;
        days -= daysPerMonth;
    }
    d = days + 1;
}

DateTime::DateTime (uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t min, uint8_t sec) {
    if (year >= 2000)
        year -= 2000;
    yOff = year;
    m = month;
    d = day;
    hh = hour;
    mm = min;
    ss = sec;
}

static uint8_t conv2d(const char* p) {
    uint8_t v = 0;
    if ('0' <= *p && *p <= '9')
        v = *p - '0';
    return 10 * v + *++p - '0';
}

// A convenient constructor for using "the compiler's time":
//   DateTime now (__DATE__, __TIME__);
// NOTE: using PSTR would further reduce the RAM footprint
DateTime::DateTime (const char* date, const char* time) {
    // sample input: date = "Dec 26 2009", time = "12:34:56"
    yOff = conv2d(date + 9);
    // Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 
    switch (date[0]) {
        case 'J': m = date[1] == 'a' ? 1 : m = date[2] == 'n' ? 6 : 7; break;
        case 'F': m = 2; break;
        case 'A': m = date[2] == 'r' ? 4 : 8; break;
        case 'M': m = date[2] == 'r' ? 3 : 5; break;
        case 'S': m = 9; break;
        case 'O': m = 10; break;
        case 'N': m = 11; break;
        case 'D': m = 12; break;
    }
    d = conv2d(date + 4);
    hh = conv2d(time);
    mm = conv2d(time + 3);
    ss = conv2d(time + 6);
}

uint8_t DateTime::dayOfWeek() const {    
    uint16_t day = get() / SECONDS_PER_DAY;
    return (day + 6) % 7; // Jan 1, 2000 is a Saturday, i.e. returns 6
}

long DateTime::get() const {
    uint16_t days = date2days(yOff, m, d);
    return time2long(days, hh, mm, ss);
}

////////////////////////////////////////////////////////////////////////////////
// RTC_DS1307 implementation

void RTC_DS1307::adjust(const DateTime& dt) {
    Wire.beginTransmission(DS1307_ADDRESS);
    Wire.write((byte) 0);
    Wire.write(bin2bcd(dt.second()));
    Wire.write(bin2bcd(dt.minute()));
    Wire.write(bin2bcd(dt.hour()));
    Wire.write(bin2bcd(0));
    Wire.write(bin2bcd(dt.day()));
    Wire.write(bin2bcd(dt.month()));
    Wire.write(bin2bcd(dt.year() - 2000));
    Wire.write((byte) 0);
    Wire.endTransmission();
}

DateTime RTC_DS1307::now() {
  	Wire.beginTransmission(DS1307_ADDRESS);
  	Wire.write((byte) 0);	
    Wire.endTransmission();

    Wire.requestFrom(DS1307_ADDRESS, 7);
    uint8_t ss = bcd2bin(Wire.read());
    uint8_t mm = bcd2bin(Wire.read());
    uint8_t hh = bcd2bin(Wire.read());
    Wire.read();
    uint8_t d = bcd2bin(Wire.read());
    uint8_t m = bcd2bin(Wire.read());
    uint16_t y = bcd2bin(Wire.read()) + 2000;
    
    return DateTime (y, m, d, hh, mm, ss);
}

///////////////////////////////////////////////////////////////////////////////
// RTC_PCF8563 implementation
// contributed by @mariusster, see http://forum.jeelabs.net/comment/1902

void RTC_PCF8563::adjust(const DateTime& dt) {
    Wire.beginTransmission(PCF8563_ADDRESS);
    Wire.write((byte) 0);
    Wire.write((byte) 0x0);                 // control/status1
    Wire.write((byte) 0x0);                 // control/status2
    Wire.write(bin2bcd(dt.second()));       // set seconds
    Wire.write(bin2bcd(dt.minute()));       // set minutes
    Wire.write(bin2bcd(dt.hour()));         // set hour
    Wire.write(bin2bcd(dt.day()));          // set day
    Wire.write((byte) 0x01);                // set weekday
    Wire.write(bin2bcd(dt.month()));        // set month, century to 1
    Wire.write(bin2bcd(dt.year() - 2000));  // set year to 00-99
    Wire.write((byte) 0x80);                // minute alarm value reset to 00
    Wire.write((byte) 0x80);                // hour alarm value reset to 00
    Wire.write((byte) 0x80);                // day alarm value reset to 00
    Wire.write((byte) 0x80);                // weekday alarm value reset to 00
    Wire.write((byte) 0x0);                 // set freqout 0= 32768khz, 1= 1hz
    Wire.write((byte) 0x0);                 // timer off
    Wire.endTransmission();
}

DateTime RTC_PCF8563::now() {
    Wire.beginTransmission(PCF8563_ADDRESS);
    Wire.write(PCF8563_SEC_ADDR);
    Wire.endTransmission();

    Wire.requestFrom(PCF8563_ADDRESS, 7);
    uint8_t ss = bcd2bin(Wire.read() & 0x7F);
    uint8_t mm = bcd2bin(Wire.read() & 0x7F);
    uint8_t hh = bcd2bin(Wire.read() & 0x3F);
    uint8_t d = bcd2bin(Wire.read() & 0x3F);
    Wire.read();
    uint8_t m = bcd2bin(Wire.read()& 0x1F);
    uint16_t y = bcd2bin(Wire.read()) + 2000;
    
    return DateTime (y, m, d, hh, mm, ss);
}

////////////////////////////////////////////////////////////////////////////////
// RTC_Millis implementation

long RTC_Millis::offset = 0;

void RTC_Millis::adjust(const DateTime& dt) {
    offset = dt.get() - millis() / 1000;
}

DateTime RTC_Millis::now() {
    return offset + millis() / 1000;
}

////////////////////////////////////////////////////////////////////////////////