// RealTimeClock
// Tim Hirzel
//
// This Code talks to a DC1307 RTC chip

#include <Wire.h>


char * daynames = "SunMonTueWedThuFriSat";
char * monthnames = "JanFebMarAprMayJunJulAugSepOctNovDec";

int readSeconds() {
  int sec = 0;
  byte b;
  Wire.beginTransmission(0x68);
  Wire.send(0x0);
  Wire.endTransmission();
  Wire.requestFrom(0x68, 1);    // request 6 bytes from slave device #2 
  b = Wire.receive(); // receive a byte as character 
  sec = 10 * (b >> 4) + (b & B00001111);
  return sec;
}

int _readFromPosition(byte position) {
  byte b;
  Wire.beginTransmission(0x68);
  Wire.send(position);
  Wire.endTransmission(); 
  Wire.requestFrom(0x68, 1);    // request 5 bytes from RTC
  b =  Wire.receive(); // receive a byte as character 
  return 10* (b >> 4) + (b & B00001111);
}

int readHour() {
  return _readFromPosition(0x2); 
}

int readMinute() {
  return _readFromPosition(0x1);
}

void readTimeString(char * timestr, boolean terminate) {
  // char * timestr = "    ";
  //  int charcount = 16;
  //  char timestr [charcount];
  byte b;
  int i;
  Wire.beginTransmission(0x68);
  Wire.send(0x1);
  Wire.endTransmission(); 
  Wire.requestFrom(0x68, 5);    // request 5 bytes from RTC
  b = Wire.receive(); // receive a byte as character 

  timestr[15] = 48 + (b & B00001111);
  timestr[14] = 48 + (b >> 4);
  timestr[13] = ':';

  b = Wire.receive(); // receive a byte as character 
  timestr[12] = 48 + (b & B00001111);
  timestr[11] = 48 + ((b & B00110000) >> 4);
  timestr[10] = ' ';

  b = Wire.receive(); // Day of Week
  int daystart =  ((int)(b & B00000111) - 1)*3;
  for (i = 0; i < 3; i++) {
    timestr[i] = daynames[daystart +i];
  }
  timestr[3] = ' ';

  b = Wire.receive(); // Date
  timestr[9] = (char) (48 + (b & B00001111));
  timestr[8] = (char) (48 + ((b & B00110000) >> 4));

  b = Wire.receive(); // Month
  int month = (10 * (int)((b & B00010000) >> 4)) + (b & B00001111);
  for (i = 0; i < 3; i++) {
    timestr[i+4] = monthnames[(month-1)*3 + i];
  }
  timestr[7] = ' ';
  if (terminate)
    timestr[16] = '\0';
}

/*

 
 int readYear() {
 return _readFromPosition(0x6);
 }    
 
 
 int readMonth() {
 return _readFromPosition(0x5);
 }
 int readDate() {
 return _readFromPosition( 0x4);
 }
 
 int readDay() {
 return _readFromPosition(0x3); 
 }
 int readSecond() {
 return _readFromPosition(0x0);
 }
 
 */


/*

 void _writeToPosition(byte val, byte position) {
 Wire.beginTransmission(0x68);
 Wire.send(position);
 Wire.send(((val/10) <<4) + (val%10 & B00001111));
 Wire.endTransmission(); 
 }
 
 void writeYear(byte year) {
 _writeToPosition(year, 0x6);
 }    
 
 
 void writeMonth(byte month) {
 _writeToPosition(month, 0x5);
 }
 void writeDate(byte date) {
 _writeToPosition(date, 0x4);
 }
 
 void writeDay(byte day) {
 _writeToPosition(day, 0x3); 
 }
 
 void writeHour(byte hour) {
 _writeToPosition(hour, 0x2); 
 }
 
 void writeMinute(byte minute) {
 _writeToPosition(minute, 0x1);
 }
 
 void writeSecond(byte second) {
 _writeToPosition(second, 0x0);
 }
 
 */