Mit einem Arduino und einem DS3231 eine kleine Uhr auf dem LCD1602-Modul erstellen.
Das Modul ist mit Speicher und einer Batterie ausgestattet. So verliert es, auch bei Stromausfall, nicht die eingestellte Uhrzeit.
Angeschlossen wird es über den I2C-Bus.
Hardware:
Elegoo Mega 2560
DS3231 RTC AT24C32 Echtzeit-Uhrenmodul für Arduino und Raspberry Pi
LCD1602-Modul Display 2×16 Zeichen
Quellcode:
#include <LiquidCrystal.h>
#include <Wire.h>
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
#define DS3231_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) );
}
void setup()
{
Wire.begin();
Serial.begin(9600);
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("Datum:");
}
void setDS3231time(byte second, byte minute, byte hour, byte dayOfWeek, byte
dayOfMonth, byte month, byte year)
{
// sets time and date data to DS3231
Wire.beginTransmission(DS3231_I2C_ADDRESS);
Wire.write(0); // set next input to start at the seconds register
Wire.write(decToBcd(second)); // set seconds
Wire.write(decToBcd(minute)); // set minutes
Wire.write(decToBcd(hour)); // set hours
Wire.write(decToBcd(dayOfWeek)); // set day of week (1=Sunday, 7=Saturday)
Wire.write(decToBcd(dayOfMonth)); // set date (1 to 31)
Wire.write(decToBcd(month)); // set month
Wire.write(decToBcd(year)); // set year (0 to 99)
Wire.endTransmission();
}
void readDS3231time(byte *second,
byte *minute,
byte *hour,
byte *dayOfWeek,
byte *dayOfMonth,
byte *month,
byte *year)
{
Wire.beginTransmission(DS3231_I2C_ADDRESS);
Wire.write(0); // set DS3231 register pointer to 00h
Wire.endTransmission();
Wire.requestFrom(DS3231_I2C_ADDRESS, 7);
// request seven bytes of data from DS3231 starting from register 00h
*second = bcdToDec(Wire.read() & 0x7f);
*minute = bcdToDec(Wire.read());
*hour = bcdToDec(Wire.read() & 0x3f);
*dayOfWeek = bcdToDec(Wire.read());
*dayOfMonth = bcdToDec(Wire.read());
*month = bcdToDec(Wire.read());
*year = bcdToDec(Wire.read());
}
void displayTime()
{
byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
// retrieve data from DS3231
readDS3231time(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month,
&year);
// send it to the serial monitor
Serial.print(hour, DEC);
// convert the byte variable to a decimal number when 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;
}
{
lcd.setCursor(7, 0);
lcd.print(dayOfMonth);
lcd.print(":");
lcd.print(month);
lcd.print(":");
lcd.print(year);
lcd.setCursor(0, 1);
lcd.print("Uhr: ");
lcd.print(hour, DEC);
lcd.print(":");
if (minute<10)
{
lcd.print("0");
}
lcd.print(minute, DEC);
lcd.print(":");
if (second<10)
{
lcd.print("0");
}
lcd.print(second, DEC);
// set up the LCD's number of columns and rows:
//lcd.begin(0, 1);
// Print a message to the LCD.
}
}
void loop()
{
displayTime(); // display the real-time clock data on the Serial Monitor,
delay(1000); // every second
}

Datenblatt:
DS3231.pdf (maximintegrated.com)
Überarbeitete Verdrahtungsversion:
Damit die Verdrahtung deutlich einfacher wird, werden die LCD-Displayˋs zukünftig mit einem I2C-Adapter verlötet. Somit braucht man nur noch zwei Stromversorgungsanschlüsse und zwei für die Seriellen Datenübertragung an A4 + A5.
Hardware zusätzlich:
LCM 1602 IIC
