now with zip file

RTClib.cpp

@@ -1,3 +1,6 @@
+// Code by JeeLabs http://news.jeelabs.org/code/
+// Released to the public domain! Enjoy!
+
 #include <Wire.h>
 #include <avr/pgmspace.h>
 #include "RTClib.h"
@@ -6,6 +9,8 @@
 #define DS1307_ADDRESS 0x68
 #define SECONDS_PER_DAY 86400L
 
+#define SECONDS_FROM_1970_TO_2000 946684800
+
 ////////////////////////////////////////////////////////////////////////////////
 // utility code, some of this could be exposed in the DateTime API if needed
 
@@ -31,7 +36,9 @@ static long time2long(uint16_t days, uint8_t h, uint8_t m, uint8_t 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) {
+DateTime::DateTime (uint32_t t) {
+  t -= SECONDS_FROM_1970_TO_2000;    // bring to 2000 timestamp from 1970
+
     ss = t % 60;
     t /= 60;
     mm = t % 60;
@@ -98,13 +105,17 @@ DateTime::DateTime (const char* date, const char* time) {
 }
 
 uint8_t DateTime::dayOfWeek() const {    
-    uint16_t day = get() / SECONDS_PER_DAY;
+    uint16_t day = secondstime() / 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);
+uint32_t DateTime::unixtime(void) const {
+  uint32_t t;
+  uint16_t days = date2days(yOff, m, d);
+  t = time2long(days, hh, mm, ss);
+  t += SECONDS_FROM_1970_TO_2000;  // seconds from 1970 to 2000
+
+  return t;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -115,8 +126,16 @@ static uint8_t bin2bcd (uint8_t val) { return val + 6 * (val / 10); }
 
 uint8_t RTC_DS1307::begin(void) {
   return 1;
+}
 
+uint8_t RTC_DS1307::isrunning(void) {
+  Wire.beginTransmission(DS1307_ADDRESS);
+  Wire.send(0);	
+  Wire.endTransmission();
 
+  Wire.requestFrom(DS1307_ADDRESS, 1);
+  uint8_t ss = Wire.receive();
+  return !(ss>>7);
 }
 
 void RTC_DS1307::adjust(const DateTime& dt) {
@@ -134,20 +153,20 @@ void RTC_DS1307::adjust(const DateTime& dt) {
 }
 
 DateTime RTC_DS1307::now() {
-  	Wire.beginTransmission(DS1307_ADDRESS);
-  	Wire.send(0);	
-    Wire.endTransmission();
-
-    Wire.requestFrom(DS1307_ADDRESS, 7);
-    uint8_t ss = bcd2bin(Wire.receive());
-    uint8_t mm = bcd2bin(Wire.receive());
-    uint8_t hh = bcd2bin(Wire.receive());
-    Wire.receive();
-    uint8_t d = bcd2bin(Wire.receive());
-    uint8_t m = bcd2bin(Wire.receive());
-    uint16_t y = bcd2bin(Wire.receive()) + 2000;
-    
-    return DateTime (y, m, d, hh, mm, ss);
+  Wire.beginTransmission(DS1307_ADDRESS);
+  Wire.send(0);	
+  Wire.endTransmission();
+  
+  Wire.requestFrom(DS1307_ADDRESS, 7);
+  uint8_t ss = bcd2bin(Wire.receive() & 0x7F);
+  uint8_t mm = bcd2bin(Wire.receive());
+  uint8_t hh = bcd2bin(Wire.receive());
+  Wire.receive();
+  uint8_t d = bcd2bin(Wire.receive());
+  uint8_t m = bcd2bin(Wire.receive());
+  uint16_t y = bcd2bin(Wire.receive()) + 2000;
+
+  return DateTime (y, m, d, hh, mm, ss);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -156,11 +175,11 @@ DateTime RTC_DS1307::now() {
 long RTC_Millis::offset = 0;
 
 void RTC_Millis::adjust(const DateTime& dt) {
-    offset = dt.get() - millis() / 1000;
+    offset = dt.secondstime() - millis() / 1000;
 }
 
 DateTime RTC_Millis::now() {
-    return offset + millis() / 1000;
+  return (uint32_t)(offset + millis() / 1000);
 }
 
 ////////////////////////////////////////////////////////////////////////////////

RTClib.h

@@ -1,11 +1,13 @@
+// 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 (long t =0);
+    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; }
@@ -15,7 +17,9 @@ class DateTime {
     uint8_t dayOfWeek() const;
 
     // 32-bit times as seconds since 1/1/2000
-    long get() const;   
+    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;
@@ -26,6 +30,7 @@ class RTC_DS1307 {
 public:
   static uint8_t begin(void);
     static void adjust(const DateTime& dt);
+    uint8_t isrunning(void);
     static DateTime now();
 };
 

examples/ds1307/ds1307.pde

@@ -9,9 +9,12 @@ void setup () {
     Serial.begin(57600);
     Wire.begin();
     RTC.begin();
-
+
+  if (! RTC.isrunning()) {
+    Serial.println("RTC is NOT running!");
     // following line sets the RTC to the date & time this sketch was compiled
-    //RTC.adjust(DateTime(__DATE__, __TIME__));
+    RTC.adjust(DateTime(__DATE__, __TIME__));
+  }
 }
 
 void loop () {
@@ -30,14 +33,14 @@ void loop () {
     Serial.print(now.second(), DEC);
     Serial.println();
 
-    Serial.print(" since 2000 = ");
-    Serial.print(now.get());
+    Serial.print(" since midnight 1/1/1970 = ");
+    Serial.print(now.unixtime());
     Serial.print("s = ");
-    Serial.print(now.get() / 86400L);
+    Serial.print(now.unixtime() / 86400L);
     Serial.println("d");
 
     // calculate a date which is 7 days and 30 seconds into the future
-    DateTime future (now.get() + 7 * 86400L + 30);
+    DateTime future (now.unixtime() + 7 * 86400L + 30);
 
     Serial.print(" now + 7d + 30s: ");
     Serial.print(future.year(), DEC);