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June 21, 2014 13:29
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Reset DS1307 real time clock
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//Arduino 1.0+ Only | |
//Arduino 1.0+ Only | |
#include "Wire.h" | |
#define DS1307_ADDRESS 0x68 | |
byte zero = 0x00; //workaround for issue #527 | |
void setup(){ | |
Wire.begin(); | |
Serial.begin(9600); | |
setDateTime(); //MUST CONFIGURE IN FUNCTION | |
} | |
void loop(){ | |
printDate(); | |
delay(1000); | |
} | |
void setDateTime(){ | |
byte second = 45; //0-59 | |
byte minute = 40; //0-59 | |
byte hour = 0; //0-23 | |
byte weekDay = 2; //1-7 | |
byte monthDay = 1; //1-31 | |
byte month = 3; //1-12 | |
byte year = 11; //0-99 | |
Wire.beginTransmission(DS1307_ADDRESS); | |
Wire.write(zero); //stop Oscillator | |
Wire.write(decToBcd(second)); | |
Wire.write(decToBcd(minute)); | |
Wire.write(decToBcd(hour)); | |
Wire.write(decToBcd(weekDay)); | |
Wire.write(decToBcd(monthDay)); | |
Wire.write(decToBcd(month)); | |
Wire.write(decToBcd(year)); | |
Wire.write(zero); //start | |
Wire.endTransmission(); | |
} | |
byte decToBcd(byte val){ | |
// Convert normal decimal numbers to binary coded decimal | |
return ( (val/10*16) + (val%10) ); | |
} | |
byte bcdToDec(byte val) { | |
// Convert binary coded decimal to normal decimal numbers | |
return ( (val/16*10) + (val%16) ); | |
} | |
void printDate(){ | |
// Reset the register pointer | |
Wire.beginTransmission(DS1307_ADDRESS); | |
Wire.write(zero); | |
Wire.endTransmission(); | |
Wire.requestFrom(DS1307_ADDRESS, 7); | |
int second = bcdToDec(Wire.read()); | |
int minute = bcdToDec(Wire.read()); | |
int hour = bcdToDec(Wire.read() & 0b111111); //24 hour time | |
int weekDay = bcdToDec(Wire.read()); //0-6 -> sunday - Saturday | |
int monthDay = bcdToDec(Wire.read()); | |
int month = bcdToDec(Wire.read()); | |
int year = bcdToDec(Wire.read()); | |
//print the date EG 3/1/11 23:59:59 | |
Serial.print(month); | |
Serial.print("/"); | |
Serial.print(monthDay); | |
Serial.print("/"); | |
Serial.print(year); | |
Serial.print(" "); | |
Serial.print(hour); | |
Serial.print(":"); | |
Serial.print(minute); | |
Serial.print(":"); | |
Serial.println(second); | |
} |
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