Epson RTC 72421 Datum und Uhrzeit stellen

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <time.h>

#include "i2c_lib.h"  // Bibliothek für I2C-Kommunikation

#define RTC_ADDRESS 0x6F  // I2C-Adresse des RTC-Chips

void set_rtc_time(int year, int month, int day, int hour, int minute, int second) {

  // Befehle zum Schreiben in die RTC-Register

  const uint8_t SECONDS_REG = 0x00;

  const uint8_t MINUTES_REG = 0x01;

  const uint8_t HOURS_REG = 0x02;

  const uint8_t DAY_REG = 0x03;

  const uint8_t MONTH_REG = 0x04;

  const uint8_t YEAR_REG = 0x05;

  // Daten für die RTC-Register vorbereiten

  uint8_t seconds = ((second / 10) << 4) | (second % 10);

  uint8_t minutes = ((minute / 10) << 4) | (minute % 10);

  uint8_t hours = ((hour / 10) << 4) | (hour % 10);

  uint8_t day = ((day / 10) << 4) | (day % 10);

  uint8_t month = ((month / 10) << 4) | (month % 10);

  uint8_t year = ((year / 10) << 4) | (year % 10);

  // Verbindung zum RTC-Chip herstellen

  int fd = i2c_init("/dev/i2c-1");  // öffne I2C-Schnittstelle

  i2c_select_device(fd, RTC_ADDRESS);  // wähle RTC-Chip auf der I2C-Schnittstelle aus

  // Sende Befehle zum Schreiben in die RTC-Register

  i2c_write_byte(fd, SECONDS_REG, seconds);

  i2c_write_byte(fd, MINUTES_REG, minutes);

  i2c_write_byte(fd, HOURS_REG, hours);

  i2c_write_byte(fd, DAY_REG, day);

  i2c_write_byte(fd, MONTH_REG, month);

  i2c_write_byte(fd, YEAR_REG, year);

  // Schließe die Verbindung zum RTC-Chip

  i2c_close(fd);

}