Data Logger Shield DS1307 MicroSD Slot

#include <Wire.h>
#include <RTClib.h>
#include <SPI.h>
#include <SD.h>

RTC_DS1307 rtc;
const int sdChipSelect = D8; // Shieldbelegung pruefen und bei Bedarf anpassen.

void setup() {
  Serial.begin(115200);
  Wire.begin(D2, D1);

  if (!rtc.begin()) {
    Serial.println("DS1307 nicht gefunden");
    while (true) delay(10);
  }
  if (!rtc.isrunning()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
  if (!SD.begin(sdChipSelect)) {
    Serial.println("MicroSD nicht bereit");
    while (true) delay(10);
  }
}

void loop() {
  DateTime now = rtc.now();
  File log = SD.open("log.csv", FILE_WRITE);
  if (log) {
    log.print(now.timestamp(DateTime::TIMESTAMP_FULL));
    log.print(',');
    log.println(millis());
    log.close();
    Serial.println("Logzeile geschrieben");
  }
  delay(5000);
}