Arduino DS1307 RTC CLOCK

1// Real time clock and calendar with set buttons using DS1307 and Arduino
2  
3// include LCD library code
4#include <LiquidCrystal.h>
5// include Wire  library code (needed for I2C protocol devices)
6#include <Wire.h>
7 
8// LCD  module connections (RS, E, D4, D5, D6, D7)
9LiquidCrystal lcd(5,6,7,8,9,10);
10  
11void setup() {
12  pinMode(3, INPUT_PULLUP);                      // button1  is connected to pin 8
13  pinMode(4, INPUT_PULLUP);                      // button2  is connected to pin 9
14  // set up the LCD's number of columns and rows
15  lcd.begin(16,  2);
16  Wire.begin();                                  // Join i2c bus
17}
18  
19char Time[]     = "TIME:  :  :  ";
20char Calendar[] = "DATE:  /  /20  ";
21byte  i, second, minute, hour, date, month, year;
22 
23void DS1307_display(){
24  //  Convert BCD to decimal
25  second = (second >> 4) * 10 + (second & 0x0F);
26  minute  = (minute >> 4) * 10 + (minute & 0x0F);
27  hour   = (hour >> 4)   * 10 + (hour  & 0x0F);
28  date   = (date >> 4)   * 10 + (date & 0x0F);
29  month  = (month  >> 4)  * 10 + (month & 0x0F);
30  year   = (year >> 4)   * 10 + (year & 0x0F);
31  // End conversion
32  Time[12]     = second % 10 + 48;
33  Time[11]     = second  / 10 + 48;
34  Time[9]      = minute % 10 + 48;
35  Time[8]      = minute / 10  + 48;
36  Time[6]      = hour   % 10 + 48;
37  Time[5]      = hour   / 10 + 48;
38  Calendar[14] = year   % 10 + 48;
39  Calendar[13] = year   / 10 + 48;
40  Calendar[9]  = month  % 10 + 48;
41  Calendar[8]  = month  / 10 + 48;
42  Calendar[6]  =  date   % 10 + 48;
43  Calendar[5]  = date   / 10 + 48;
44  lcd.setCursor(0, 0);
45  lcd.print(Time);                               // Display time
46  lcd.setCursor(0,  1);
47  lcd.print(Calendar);                           // Display calendar
48}
49void  blink_parameter(){
50  byte j = 0;
51  while(j < 10 && digitalRead(3) && digitalRead(4)){
52    j++;
53    delay(25);
54  }
55}
56byte edit(byte x, byte y, byte parameter){
57  char text[3];
58  while(!digitalRead(3));                        // Wait until  button (pin #8) released
59  while(true){
60    while(!digitalRead(4)){                      //  If button (pin #9) is pressed
61      parameter++;
62      if(i == 0 && parameter  > 23)               // If hours > 23 ==> hours = 0
63        parameter = 0;
64      if(i == 1 && parameter > 59)               // If minutes > 59 ==> minutes  = 0
65        parameter = 0;
66      if(i == 2 && parameter > 31)               //  If date > 31 ==> date = 1
67        parameter = 1;
68      if(i == 3 && parameter  > 12)               // If month > 12 ==> month = 1
69        parameter = 1;
70      if(i == 4 && parameter > 99)               // If year > 99 ==> year = 0
71        parameter = 0;
72      sprintf(text,"%02u", parameter);
73      lcd.setCursor(x,  y);
74      lcd.print(text);
75      delay(200);                                //  Wait 200ms
76    }
77    lcd.setCursor(x, y);
78    lcd.print("  ");                             //  Display two spaces
79    blink_parameter();
80    sprintf(text,"%02u", parameter);
81    lcd.setCursor(x, y);
82    lcd.print(text);
83    blink_parameter();
84    if(!digitalRead(3)){                         // If button (pin #8) is pressed
85      i++;                                       //  Increament 'i' for the next parameter
86      return parameter;                          //  Return parameter value and exit
87    }
88  }
89}
90 
91void loop() {
92  if(!digitalRead(3)){                           // If button (pin #8) is pressed
93      i = 0;
94      hour   = edit(5, 0, hour);
95      minute = edit(8, 0, minute);
96      date   = edit(5, 1, date);
97      month  = edit(8, 1, month);
98      year   = edit(13,  1, year);
99      // Convert decimal to BCD
100      minute = ((minute / 10) <<  4) + (minute % 10);
101      hour = ((hour / 10) << 4) + (hour % 10);
102      date  = ((date / 10) << 4) + (date % 10);
103      month = ((month / 10) << 4) + (month  % 10);
104      year = ((year / 10) << 4) + (year % 10);
105      // End conversion
106      // Write data to DS1307 RTC
107      Wire.beginTransmission(0x68);               //  Start I2C protocol with DS1307 address
108      Wire.write(0);                              //  Send register address
109      Wire.write(0);                              // Reset  sesonds and start oscillator
110      Wire.write(minute);                         //  Write minute
111      Wire.write(hour);                           // Write hour
112      Wire.write(1);                              // Write day (not used)
113      Wire.write(date);                           // Write date
114      Wire.write(month);                          //  Write month
115      Wire.write(year);                           // Write year
116      Wire.endTransmission();                     // Stop transmission and release  the I2C bus
117      delay(200);                                 // Wait 200ms
118    }
119    Wire.beginTransmission(0x68);                 // Start I2C protocol  with DS1307 address
120    Wire.write(0);                                // Send  register address
121    Wire.endTransmission(false);                  // I2C restart
122    Wire.requestFrom(0x68, 7);                    // Request 7 bytes from DS1307  and release I2C bus at end of reading
123    second = Wire.read();                         //  Read seconds from register 0
124    minute = Wire.read();                         //  Read minuts from register 1
125    hour   = Wire.read();                         //  Read hour from register 2
126    Wire.read();                                  //  Read day from register 3 (not used)
127    date   = Wire.read();                         //  Read date from register 4
128    month  = Wire.read();                         //  Read month from register 5
129    year   = Wire.read();                         //  Read year from register 6
130    DS1307_display();                             //  Diaplay time & calendar
131    delay(50);                                    //  Wait 50ms
132}