rtc_oled.ino

#include <Wire.h>
#include <TimeLib.h>
#include <DS1307RTC.h>

#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128     // OLED display width, in pixels
#define SCREEN_HEIGHT 32     // OLED display height, in pixels

#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire);

const char *monthName[12] = {
  "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};

tmElements_t tm;

void setup() {
  bool parse=false;
  bool config=false;

  // get the date and time the compiler was run
  if (getDate(__DATE__) && getTime(__TIME__)) {
    parse = true;
    // and configure the RTC with this info
    if (RTC.write(tm)) {
      config = true;
    }
  }

  Serial.begin(9600);

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  
  while (!Serial) ; // wait for Arduino Serial Monitor
  delay(200);
  
  if (parse && config) {
    Serial.print("DS1307 configured Time=");
    Serial.print(__TIME__);
    Serial.print(", Date=");
    Serial.println(__DATE__);
  } else if (parse) {
    Serial.println("DS1307 Communication Error :-{");
    Serial.println("Please check your circuitry");
  } else {
    Serial.print("Could not parse info from the compiler, Time=\"");
    Serial.print(__TIME__);
    Serial.print("\", Date=\"");
    Serial.print(__DATE__);
    Serial.println("\"");
  }
}

void loop() {
    tmElements_t tm;

  if (RTC.read(tm)) {
  int prevSec;
  String currentDateTime;

  currentDateTime = (String) readTime();

  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(2);
  display.setCursor(0,0);

  display.print(currentDateTime);
  Serial.println(currentDateTime);
  display.display();
  } else {
    if (RTC.chipPresent()) {
      Serial.println("The DS1307 is stopped.  Please run the SetTime");
      Serial.println("example to initialize the time and begin running.");
      Serial.println();
    } else {
      Serial.println("DS1307 read error!  Please check the circuitry.");
      Serial.println();
    }
    delay(9000);
  }
  delay(1000);
}

bool getTime(const char *str)
{
  int Hour, Min, Sec;

  if (sscanf(str, "%d:%d:%d", &Hour, &Min, &Sec) != 3) return false;
  tm.Hour = Hour;
  tm.Minute = Min;
  tm.Second = Sec;
  return true;
}

bool getDate(const char *str)
{
  char Month[12];
  int Day, Year;
  uint8_t monthIndex;

  if (sscanf(str, "%s %d %d", Month, &Day, &Year) != 3) return false;
  for (monthIndex = 0; monthIndex < 12; monthIndex++) {
    if (strcmp(Month, monthName[monthIndex]) == 0) break;
  }
  if (monthIndex >= 12) return false;
  tm.Day = Day;
  tm.Month = monthIndex + 1;
  tm.Year = CalendarYrToTm(Year);
  return true;
}

void print2digits(int number) {
  if (number >= 0 && number < 10) {
    Serial.write('0');
  }
  Serial.print(number);
}

String readTime() {
tmElements_t tm;
if (RTC.read(tm)) {
    String currentDateTime =  returnTwoDigits(tm.Hour) + ":" + returnTwoDigits(tm.Minute) + ":" + returnTwoDigits(tm.Second) + "\n" + returnTwoDigits(tm.Day) + "/" + returnTwoDigits(tm.Month) + '/' + (String)tmYearToCalendar(tm.Year);
    return currentDateTime;
  } else {
    if (RTC.chipPresent()) {
      return "DS1307 stopped! Run setTime";
    } else {
      return "DS1307 read error!";
    }
  }
}

String returnTwoDigits(int number) {
  if (number >= 0 && number < 10) {
    return '0'+ (String) number;
  }
  return (String) number;
}













/*

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#include <Time.h>                       //For using RTC 1306 Module on I2c bus
#include <DS1307RTC.h>


#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire);

void setup() {
  Serial.begin(9600);

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }

  // Show initial display buffer contents on the screen --
  // the library initializes this with an Adafruit splash screen.
  display.display();
}

void loop() {

  int prevSec;
  String currentDateTime;

  currentDateTime = (String) readTime();

  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(2);
  display.setCursor(0,0);

  display.print(currentDateTime);
  Serial.println(currentDateTime);
  display.display();

  delay(1000);
}

String readTime() {
tmElements_t tm;
if (RTC.read(tm)) {
    String currentDateTime =  returnTwoDigits(tm.Hour) + ":" + returnTwoDigits(tm.Minute) + ":" + returnTwoDigits(tm.Second) + "\n" + returnTwoDigits(tm.Day) + "/" + returnTwoDigits(tm.Month) + '/' + (String)tmYearToCalendar(tm.Year);
    return currentDateTime;
  } else {
    if (RTC.chipPresent()) {
      return "DS1307 stopped! Run setTime";
    } else {
      return "DS1307 read error!";
    }
  }
}

String returnTwoDigits(int number) {
  if (number >= 0 && number < 10) {
    return '0'+ (String) number;
  }
  return (String) number;
}

*/