Hi all,

This code below is not my own work but is exactly what I need for my project, the code runs a real time clock through an Arduno Duo development board as it's micro-controller using an I2C connection if that all makes sense. The problem is when running the RTC through a virtual serial port, the time will not increment!!! I've spent days now trying to get this to work but no such luck, if anyone can see what I cannot... please let me know and thank you very much in advance

- Gary

#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68

// Convert normal decimal numbers to binary coded decimal
byte decToBcd(byte val)
  return ( (val/10*16) + (val%10) );

// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
  return ( (val/16*10) + (val%16) );

// Stops the DS1307, but it has the side effect of setting seconds to 0
// Probably only want to use this for testing
/*void stopDs1307()

// 1) Sets the date and time on the ds1307
// 2) Starts the clock
// 3) Sets hour mode to 24 hour clock
// Assumes you're passing in valid numbers
void setDateDs1307(byte second,        // 0-59
                   byte minute,        // 0-59
                   byte hour,          // 1-23
                   byte dayOfWeek,     // 1-7
                   byte dayOfMonth,    // 1-28/29/30/31
                   byte month,         // 1-12
                   byte year)          // 0-99
   Wire.send(decToBcd(second));    // 0 to bit 7 starts the clock
   Wire.send(decToBcd(hour));      // If you want 12 hour am/pm you need to set
                                   // bit 6 (also need to change readDateDs1307)

// Gets the date and time from the ds1307
void getDateDs1307(byte *second,
          byte *minute,
          byte *hour,
          byte *dayOfWeek,
          byte *dayOfMonth,
          byte *month,
          byte *year)
  // Reset the register pointer

  Wire.requestFrom(DS1307_I2C_ADDRESS, 7);

  // A few of these need masks because certain bits are control bits
  *second     = bcdToDec(Wire.receive() & 0x7f);
  *minute     = bcdToDec(Wire.receive());
  *hour       = bcdToDec(Wire.receive() & 0x3f);  // Need to change this if 12 hour am/pm
  *dayOfWeek  = bcdToDec(Wire.receive());
  *dayOfMonth = bcdToDec(Wire.receive());
  *month      = bcdToDec(Wire.receive());
  *year       = bcdToDec(Wire.receive());

void setup()
  byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;

  // Change these values to what you want to set your clock to.
  // You probably only want to set your clock once and then remove
  // the setDateDs1307 call.
  second = 45;
  minute = 3;
  hour = 7;
  dayOfWeek = 5;
  dayOfMonth = 17;
  month = 4;
  year = 8;
  setDateDs1307(second, minute, hour, dayOfWeek, dayOfMonth, month, year);

void loop()
  byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;

  getDateDs1307(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year);
  Serial.print(hour, DEC);
  Serial.print(minute, DEC);
  Serial.print(second, DEC);
  Serial.print("  ");
  Serial.print(month, DEC);
  Serial.print(dayOfMonth, DEC);
  Serial.print(year, DEC);
  Serial.print("  Day_of_week:");
  Serial.println(dayOfWeek, DEC);


P.S the virtual serial port is embedded in the Arduino IDE which is free to download from www.Arduino.cc if anyone was interested in knowing!!!

My mistake, I've just found a fault in my wiring, when I changed digital 4 & 5 to analog 4 & 5 it fired right up!!! sorry if I wasted anyone's time on this.

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