[arduino code examples for F24]-07 how to DS3231 RTC clock

Code:
/*

 * Made by KinCony IoT: https://www.kincony.com

 *

 * DS3231 RTC with Arduino

 *

 * This program demonstrates how to use the DS3231 RTC (Real-Time Clock) module with the Arduino.

 * It includes functionality to:

 * - Initialize the DS3231 RTC module

 * - Read the current date and time from the RTC

 * - Set the RTC time based on a serial command:Command format: DYYYY-MM-DDTHH:MM:SS

 *

 * Hardware Connections:

 * - SDA: GPIO 8

 * - SCL: GPIO 18

 */



#include <DS3231.h>

#include <Wire.h>



String serial_cmd_rcv = ""; // Serial port receiver



typedef struct

{

  byte year;    // Last two digits of the year, library adds 2000.

  byte month;

  byte day;

  byte hour;

  byte minute;

  byte second;

} MY_DATE_STR;



MY_DATE_STR my_date_str = {0};



// Define constants for relay control

#define OPEN_RLY_DATA    26

#define OPEN_RLY_MONTH   4

#define CLOSE_RLY_DATA   2

#define CLOSE_RLY_MONTH  5



// Define pin connections

#define SDA_PIN   8

#define SCL_PIN   18



DS3231 rtc; // Create an instance of the DS3231 RTC

bool h12Flag;

bool pmFlag;

static bool bCentury = false;

static bool old_level_high = false;

static bool old_level_low = false;





/**

 * @brief Print the current time from the RTC to the Serial Monitor.

 */

static void PrintfCurTime()

{

  Serial.print("Current time is: ");

  int year = rtc.getYear() + 2000;

  Serial.print(year);

  Serial.print("-");



  Serial.print(rtc.getMonth(bCentury), DEC);

  Serial.print("-");



  Serial.print(rtc.getDate(), DEC);

  Serial.print(" ");



  Serial.print(rtc.getHour(h12Flag, pmFlag), DEC);

  Serial.print(":");

  Serial.print(rtc.getMinute(), DEC);

  Serial.print(":");

  Serial.println(rtc.getSecond(), DEC);

}



/**

 * @brief Process serial commands to set the RTC time.

 * Command format: DYYYY-MM-DDTHH:MM:SS

 */

static void GetSerialCmd()

{

  if (Serial.available() > 0)

  {

    delay(100);

    int num_read = Serial.available();

    while (num_read--)

      serial_cmd_rcv += char(Serial.read());

  }

  else return;



  serial_cmd_rcv.trim();



  if (serial_cmd_rcv == "current time")

  {

    PrintfCurTime();

    serial_cmd_rcv = "";

    return;

  }



  Serial.print("Received length: ");

  Serial.println(serial_cmd_rcv.length());



  int indexof_d = serial_cmd_rcv.indexOf('D');

  int indexof_t = serial_cmd_rcv.indexOf('T');



  Serial.print("D index: ");

  Serial.print(indexof_d);

  Serial.print(" T index: ");

  Serial.println(indexof_t);



  if (serial_cmd_rcv.length() != 20 || 

      serial_cmd_rcv.substring(0, 1) != "D" ||

      serial_cmd_rcv.substring(11, 12) != "T")  

  {

    Serial.println(serial_cmd_rcv);

    serial_cmd_rcv = "";

    return;

  }



  Serial.println("Setting time...");



  my_date_str.year = (byte)serial_cmd_rcv.substring(3, 5).toInt();

  my_date_str.month = (byte)serial_cmd_rcv.substring(6, 8).toInt();

  my_date_str.day = (byte)serial_cmd_rcv.substring(9, 11).toInt();

  my_date_str.hour = (byte)serial_cmd_rcv.substring(12, 14).toInt();

  my_date_str.minute = (byte)serial_cmd_rcv.substring(15, 17).toInt();

  my_date_str.second = (byte)serial_cmd_rcv.substring(18).toInt();



  rtc.setYear(my_date_str.year);

  rtc.setMonth(my_date_str.month);

  rtc.setDate(my_date_str.day);

  rtc.setHour(my_date_str.hour);

  rtc.setMinute(my_date_str.minute);

  rtc.setSecond(my_date_str.second);



  serial_cmd_rcv = "";



  Serial.println("Time set.");

}



void setup() {

  // Initialize the I2C interface

  Wire.begin(SDA_PIN, SCL_PIN, 40000);

  

  // Initialize Serial communication

  Serial.begin(115200);

   

  // Set the RTC to 24-hour mode

  rtc.setClockMode(false); // 24-hour format



  // Print current time to Serial Monitor

  PrintfCurTime();



  // Clear any remaining serial data

  while (Serial.read() >= 0) {}

}



void loop() {

  // Process incoming serial commands

  GetSerialCmd(); 

  delay(1000); // Delay for 1 second

}