RTC 3231 problem

Projects Networking, Protocols, and Devices
1 
// Date and time functions using a DS3231 RTC connected via I2C and Wire lib
#include <Wire.h>
#include "RTClib.h"

RTC_DS3231 rtc;

char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

void setup () {

#ifndef ESP8266
  while (!Serial); // for Leonardo/Micro/Zero
#endif

  Serial.begin(9600);

  delay(3000); // wait for console opening

  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }

  if (rtc.lostPower()) {
    Serial.println("RTC lost power, lets set the time!");
    // following line sets the RTC to the date & time this sketch was compiled
    //rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
    // This line sets the RTC with an explicit date & time, for example to set
    // January 21, 2014 at 3am you would call:
    rtc.adjust(DateTime(2016, 3, 30, 12, 40, 20));

  }
}

void loop () {
    DateTime now = rtc.now();
    
    Serial.print(now.day(), DEC);
    Serial.print('/');
    Serial.print(now.month(), DEC);
    Serial.print('/');
    Serial.print(now.year(), DEC);
    Serial.print(" (");
    Serial.print(daysOfTheWeek[now.dayOfTheWeek()]);
    Serial.print(") ");
    Serial.print(now.hour(), DEC);
    Serial.print(':');
    Serial.print(now.minute(), DEC);
    Serial.print(':');
    Serial.print(now.second(), DEC);
    Serial.println();
    delay(1000);
    
}

the rtc stil output the time: 11:15:00 instead 12

2

How about a link to where you found the library? I can't get it to compile with my libraries.

3

https://github.com/adafruit/RTClibhttps://github.com/adafruit/RTClib

4 
if (rtc.lostPower()) {
    Serial.println("RTC lost power, lets set the time!");
    // following line sets the RTC to the date & time this sketch was compiled
    //rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
    // This line sets the RTC with an explicit date & time, for example to set
    // January 21, 2014 at 3am you would call:
    rtc.adjust(DateTime(2016, 3, 30, 12, 40, 20));

  }

Your sketch only set the DateTime if rtc.lostPower returns a certain bit set in the status register.

bool RTC_DS3231::lostPower(void) {
  return (read_i2c_register(DS3231_ADDRESS, DS3231_STATUSREG) >> 7);
}

If the rtc has not lost battery power and actually stopped and set the register bit, you will not enter the conditional code to adjust the DateTime.

If you want to set the DateTime, just pull the rtc.Adjust() function outside of the a lostPower conditional test.

5

it works

i put it between the "}" and " if (rtc.lostPower()) {"