SD Card Example

/* Thank you wemos
 * Micro SD Shield - Basic file example
 *
 * This example shows how to create and destroy an SD card file
 *
 * The WeMos Micro SD Shield uses:
 * D5, D6, D7, D8, 3V3 and G
 *
 * The shield uses SPI bus pins:
 * D5 = CLK
 * D6 = MISO
 * D7 = MOSI
 * D8 = CS
 *
 * The SD card library uses 8.3 format filenames and is case-insensitive.
 * eg. IMAGE.JPG is the same as image.jpg
 *
 * created Nov 2010 by David A. Mellis
 * modified 9 Apr 2012 by Tom Igoe
 *
 * This example code is in the public domain.
 * https://github.com/esp8266/Arduino/blob/master/libraries/SD/examples/Files/Files.ino
 */

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

const int chipSelect = D8;
File myFile;

void setup()
{
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  Serial.print("Initializing SD card...");

  if (!SD.begin(chipSelect)) {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");

  if (SD.exists("example.txt")) {
    Serial.println("example.txt exists.");
  }
  else {
    Serial.println("example.txt doesn't exist.");
  }

  // open a new file and immediately close it:
  Serial.println("Creating example.txt...");
  myFile = SD.open("example.txt", FILE_WRITE);
  myFile.close();

  // Check to see if the file exists:
  if (SD.exists("example.txt")) {
    Serial.println("example.txt exists.");
  }
  else {
    Serial.println("example.txt doesn't exist.");
  }

  // delete the file:
  Serial.println("Removing example.txt...");
  SD.remove("example.txt");

  if (SD.exists("example.txt")) {
    Serial.println("example.txt exists.");
  }
  else {
    Serial.println("example.txt doesn't exist.");
  }
}

void loop()
{
  // nothing happens after setup
}