View source for WeMOS: D1 R1 mini LCD DS1307 I2C RTC

Library

 https://github.com/Naguissa/uRTCLib


Code

 #include "Arduino.h"
 #include "uRTCLib.h"
 // uRTCLib rtc;
 uRTCLib rtc(0x68);
 /*
  I2C LCD  ESP8266-Wenos D1 Mini
  GND          GND
  VCC          VIN
  SDA          D2
  SCL          D1
 */
 #include <LiquidCrystal_I2C.h>
 
 // set the LCD number of columns and rows
 int lcdColumns = 16;
 int lcdRows = 2;
 
 LiquidCrystal_I2C lcd(0x27, lcdColumns, lcdRows); 
 
 char cMonth[12][4] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
 char DoW[7][10] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
 
 void setup() {
   Serial.begin(9600);
   // delay(3000); // wait for console opening 
 
   URTCLIB_WIRE.begin();
 
   // Comment out below line once you set the date & time.
   // Following line sets the RTC with an explicit date & time
   // for example to set January 13 2022 at 12:56 you would call:
   // rtc.set(0, 56, 12, 5, 13, 1, 22);
   // rtc.set(second, minute, hour, dayOfWeek, dayOfMonth, month, year)
   // set day of week (1=Sunday, 7=Saturday)
 
   lcd.begin( 5, 4 );// initialize LCD
   lcd.init();
   // turn on LCD backlight                      
   lcd.backlight();
   lcd.clear(); 
 }
 
 void loop() {
   rtc.refresh();  
 
   lcd.setCursor(0,0);
   lcd.print( DoW[rtc.dayOfWeek()] );
   lcd.print(", ");
   lcd.print(rtc.day());
   lcd.print(' ');
   // lcd.print(rtc.month());
   lcd.print(cMonth[rtc.month()-1]);
   lcd.print(' ');
   lcd.print(2000+rtc.year()); 
 
   lcd.setCursor(4,1);
   print2digits(rtc.hour());
   lcd.print(':');
   print2digits(rtc.minute());
   lcd.print(':');
   print2digits(rtc.second());
      
   delay(1000);
 }
  
 void print2digits(int number) {
   if (number >= 0 && number < 10) {
     lcd.write('0');
   }
   lcd.print(number);
 }