IrtcSet() sets the RTC date and time.

bool IrtcSet(uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second)
bool IrtcSet(uint16_t year, uint8_t month, uint8_t day, uint8_t dayOfWeek, uint8_t hour, uint8_t minute, uint8_t second)

void setup() {
  Serial.begin(115200);
 
  if (!IrtcBegin()) {
    Serial.println(F("DS3231 connection failed"));
    return;
  }
 
  // Run once initially, then comment out.
  // IrtcSet(2026, 8, 10, 14, 30, 0);
}
 
void loop() {
  IrtcDateTime now;
  if (IrtcRead(now)) {
    Serial.print(now.year);
    Serial.print('/');
    Serial.print(now.month);
    Serial.print('/');
    Serial.print(now.day);
    Serial.print(' ');
    Serial.print(now.hour);
    Serial.print(':');
    Serial.print(now.minute);
    Serial.print(':');
    Serial.println(now.second);
  }
  delay(1000);
}

Run each device's corresponding Begin command first. Check I²C addresses and pin sharing; if the bool return value is false, inspect wiring and power.

← Built-in Command List