/* RTC DS1307  interrupt demo */


#include <Wire.h>

int ledp = 13;
int intp = 2;                  // dig port int0:PD2 (dig-2)

volatile boolean ledst = LOW;
volatile boolean intst = LOW;

// DS1307 registers

#define DS1307  0xD0 >> 1     //  ID code
#define RTsec 0
//#define RTmin 1
//#define RThour 2

// DS1307 buffer

byte sec, xmin, hour, day, date, month, year, ctrl;

void setup(){
  Serial.begin(19200);
  Wire.begin();
  pinMode(ledp,OUTPUT);
  pinMode(intp,INPUT);

  sec = 0x55;
  xmin = 0x59;
  hour = 0x23;
  day = 0x07;
  date = 0x31;
  month = 0x12;
  year = 0x08;
  ctrl = 0x10;
  SetClock();
  Serial.println("demo RTC interrupt\n");
  attachInterrupt(0,RTCint, CHANGE);       // setup interrupt
}

void RTCint(){
  if(digitalRead(intp) == LOW){
    intst = HIGH;                   // set interrupt status
    digitalWrite(ledp,HIGH);
  }else
    digitalWrite(ledp,LOW);
}
  
void loop(){
  while(intst == 0);		// wait for interrupt
  GetClock();
  printhex(hour);
  Serial.print(":");
  printhex(min);
  Serial.print(":");
  printhex(sec);
  Serial.println();
  intst = 0;                   // reset int status
}

void SetClock(){
  Wire.beginTransmission(DS1307);
  Wire.write(RTsec);
  Wire.write(sec);
  Wire.write(xmin);
  Wire.write(hour);
  Wire.write(day);
  Wire.write(date);
  Wire.write(month);
  Wire.write(year);
  Wire.write(ctrl);
  Wire.endTransmission();
}

void GetClock(){
  Wire.beginTransmission(DS1307);
  Wire.write(RTsec);
  Wire.endTransmission();
  Wire.requestFrom(DS1307,8);
  sec = Wire.read();
  xmin = Wire.read();
  hour = Wire.read();
  day = Wire.read();
  date = Wire.read();
  month = Wire.read();
  year = Wire.read();
  ctrl = Wire.read();
}

void printhex(byte val){
  if(val < 0x10)
    Serial.print(val);
  else
    Serial.print(val,HEX);
}