Hi,
I’ve got an RTC DS1307 module from Sparkfun. Hardware connections are as follows:
SDA- Analog pin #4, SCL-Analog pin #5, 5v-5v Arduino, and gnd-gnd Arduino are connected. Two 1/8w 4.7k’s were connected as pull-up resistors for SDA and SCL.
I found that john at tronixstuff.com has prepared wonderful step-by-step tutorials for the RTC ds1307.
I tried the pde example from tronixstuff.com, Example 7.3(pdf), with minimum changes(date, time,…).
The code was compiled, and uploaded to Arduino Diecimila.(setting mode)
The code section for the time-setting was then commented out for ‘running time’ mode. Again, it was compiled, and uploaded to the Diecimila, and Serial monitor was initialized.
The result?
45:165:15 165/165/165 Day of week:165
45:165:15 165/165/165 Day of week:165
45:165:15 165/165/165 Day of week:165
45:165:15 165/165/165 Day of week:165
45:165:15 165/165/165 Day of week:165
This output pattern is not very consistent, though.
I am not sure whether this problem is due to the RTC or the pde.
Any suggestions are welcome.
/*
Example 7.3 -- YR, DATE, TIME adjusted---
reading and writing to the Maxim DS1307 real time clock IC
tronixstuff.com/tutorials
based on code by Maurice Ribble
17-4-2008 - http://www.glacialwanderer.com/hobbyrobotics
*/
#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) );
}
// 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.beginTransmission(DS1307_I2C_ADDRESS);
Wire.send(0);
Wire.send(decToBcd(second)); // 0 to bit 7 starts the clock
Wire.send(decToBcd(minute));
Wire.send(decToBcd(hour));
Wire.send(decToBcd(dayOfWeek));
Wire.send(decToBcd(dayOfMonth));
Wire.send(decToBcd(month));
Wire.send(decToBcd(year));
Wire.send(0x10); // sends 0x10 (hex) 00010000 (binary) to control register - turns on square wave
Wire.endTransmission();
}
// 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.beginTransmission(DS1307_I2C_ADDRESS);
Wire.send(0);
Wire.endTransmission();
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;
Wire.begin();
Serial.begin(9600);
// 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 = 0;
minute = 12;
hour = 23;
dayOfWeek = 7;
dayOfMonth = 25;
month = 7;
year = 10;
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);// convert the byte variable to a decimal number when being displayed
Serial.print(":");
if (minute<10)
{
Serial.print("0");
}
Serial.print(minute, DEC);
Serial.print(":");
if (second<10)
{
Serial.print("0");
}
Serial.print(second, DEC);
Serial.print(" ");
Serial.print(dayOfMonth, DEC);
Serial.print("/");
Serial.print(month, DEC);
Serial.print("/");
Serial.print(year, DEC);
Serial.print(" Day of week:");
switch(dayOfWeek){
case 1:
Serial.println("Sunday");
break;
case 2:
Serial.println("Monday");
break;
case 3:
Serial.println("Tuesday");
break;
case 4:
Serial.println("Wednesday");
break;
case 5:
Serial.println("Thursday");
break;
case 6:
Serial.println("Friday");
break;
case 7:
Serial.println("Saturday");
break;
}
Serial.println(dayOfWeek, DEC);
delay(1000);
}
Thanks.
Bryan
- they both work great.