Hi all,
Ive undertaken a project to make a clock using the DS1307 RTC chip. I've used these chips before while trying to learn Arduino coding and been generally successful but i'm stumped on part of the code i'm trying to write now. I'd like to use external push buttons to be able to set and adjust the time as a stand alone unit without having to plug into my computer.
I've found some code at this link
http://www.bristolwatch.com/arduino/arduino_ds1307.htm
which is doing pretty much what i want however it only adjusts the hours and minutes. I'd like to be able to adjust the date as well. Ive tried copying the "hours" portion and changing it to month and using a 4th switch (SW03) but although it says that i am adjusting the month in the serial monitor, it doesnt actually change the month on the chip.
I'm also slowly getting my head around binary, dec, bcd and hex etc but cant understand part of the "change time" script at the end. It says
if ((minutes & 0x0f) > 9) minutes = minutes + 6;
Whats happening here?
Here is the code that i have adjusted. Could someone please take a look and tell me why the month isn't changing even though the serial monitor says it is?
#include <Wire.h> // specify use of Wire.h library.
byte blinkPin = 13;
byte SW0 = 4;
byte SW1 = 5;
byte SW2 = 6;
byte SW3 = 7;
void setup()
{
Wire.begin(); // join i2c bus (address optional for master)
Serial.begin(9600);
pinMode(blinkPin, OUTPUT);
digitalWrite(blinkPin, 0);
pinMode(SW0, INPUT); // Set Time (for this use a slide switch)
pinMode(SW1, INPUT); // Set Date (for this use a slide switch)
pinMode(SW2, INPUT); // N.O. push button switch
pinMode(SW3, INPUT); // N.O. push button switch
digitalWrite(SW0, HIGH); // pull-ups on
digitalWrite(SW1, HIGH);
digitalWrite(SW2, HIGH);
digitalWrite(SW3, HIGH);
}
void loop()
{
Wire.beginTransmission(0x68);
Wire.send(0);
Wire.endTransmission();
Wire.requestFrom(0x68, 7);
byte secs = Wire.receive();
byte mins = Wire.receive();
byte hrs = Wire.receive();
byte day = Wire.receive();
byte date = Wire.receive();
byte month = Wire.receive();
byte year = Wire.receive();
// hours, minutes, seconds
Serial.print("The time is ");
if (hrs < 10) Serial.print("0");
Serial.print(hrs,HEX);
Serial.print(":");
if (mins < 10) Serial.print("0");
Serial.print(mins, HEX);
Serial.print(":");
if (secs < 10) Serial.print("0");
Serial.println(secs, HEX);
// use MM-DD-YYYY
Serial.print("The date is ");
if (month < 10) Serial.print("0");
Serial.print(month,HEX);
Serial.print("-");
if (date < 10) Serial.print("0");
Serial.print(date, HEX);
Serial.print("-");
Serial.print("20");
if (year < 10) Serial.print("0");
Serial.println(year, HEX);
Serial.println();
if (!(digitalRead(SW0))) set_time(); // hold the switch to set time
delay(1000); //wait a second before next output
toggle(blinkPin);
}
// toggle the state on a pin
void toggle(int pinNum)
{
int pinState = digitalRead(pinNum);
pinState = !pinState;
digitalWrite(pinNum, pinState);
}
void set_time() {
byte minutes = 0;
byte hours = 0;
byte month = 0;
{
while (!digitalRead(SW0)) // set time switch must be released to exit
{
while (!digitalRead(SW1)) // set minutes
{
minutes++;
if ((minutes & 0x0f) > 9) minutes = minutes + 6;
if (minutes > 0x59) minutes = 0;
Serial.print("Minutes = ");
if (minutes <= 9) Serial.print("0");
Serial.println(minutes, HEX);
delay(200);
}
while (!digitalRead(SW2)) // set hours
{
hours++;
if ((hours & 0x0f) > 9) hours = hours + 6;
if (hours > 0x23) hours = 0;
Serial.print("Hours = ");
if (hours <= 9) Serial.print("0");
Serial.println(hours, HEX);
delay(200);
}
while (!digitalRead(SW3)) // set date
{
month++;
if ((month & 0x0f) > 9) month = month + 6;
if (month > 0x12) month = 0;
Serial.print("month = ");
if (month <= 9) Serial.print("0");
Serial.println(month, HEX);
delay(200);
}
}
}
Wire.beginTransmission(0x68); // activate DS1307
Wire.send(0); // where to begin
Wire.send(0x00); //seconds
Wire.send(minutes); //minutes
Wire.send(0x80 | hours); //hours (24hr time)
Wire.send(0x06); // Day 01-07
Wire.send(0x01); // Date 0-31
Wire.send(0x05); // month 0-12
Wire.send(0x09); // Year 00-99
Wire.send(0x10); // Control 0x10 produces a 1 HZ square wave on pin 7.
Wire.endTransmission();
}
Also, why is it that the Wire.send code at the end uses (0x09) for the year ( i believe this is somehow the address but looking at the datasheet, can't figure out how) but (minutes) for the minutes?
Thanks so much everyone. Any help is always appreciated!
edit: changed 31 to 12 in the change month part
