First init.

libraries/SD/examples/DumpFile/DumpFile.ino

@@ -0,0 +1,65 @@
+/*
+  SD card file dump
+
+  This example shows how to read a file from the SD card using the
+  SD library and send it over the serial port.
+  Pin numbers reflect the default SPI pins for Uno and Nano models.
+
+  The circuit:
+   SD card attached to SPI bus as follows:
+ ** SDO - pin 11
+ ** SDI - pin 12
+ ** CLK - pin 13
+ ** CS - depends on your SD card shield or module.
+ 		Pin 10 used here for consistency with other Arduino examples
+   (for MKR Zero SD: SDCARD_SS_PIN)
+
+  created  22 December 2010
+  by Limor Fried
+  modified 9 Apr 2012
+  by Tom Igoe
+
+  This example code is in the public domain.
+*/
+#include <SD.h>
+
+const int chipSelect = 10;
+
+void setup() {
+  // Open serial communications and wait for port to open:
+  Serial.begin(9600);
+  // wait for Serial Monitor to connect. Needed for native USB port boards only:
+  while (!Serial);
+
+  Serial.print("Initializing SD card...");
+
+  if (!SD.begin(chipSelect)) {
+    Serial.println("initialization failed. Things to check:");
+    Serial.println("1. is a card inserted?");
+    Serial.println("2. is your wiring correct?");
+    Serial.println("3. did you change the chipSelect pin to match your shield or module?");
+    Serial.println("Note: press reset button on the board and reopen this Serial Monitor after fixing your issue!");
+    while (true);
+  }
+
+  Serial.println("initialization done.");
+
+  // open the file. note that only one file can be open at a time,
+  // so you have to close this one before opening another.
+  File dataFile = SD.open("datalog.txt");
+
+  // if the file is available, write to it:
+  if (dataFile) {
+    while (dataFile.available()) {
+      Serial.write(dataFile.read());
+    }
+    dataFile.close();
+  }
+  // if the file isn't open, pop up an error:
+  else {
+    Serial.println("error opening datalog.txt");
+  }
+}
+
+void loop() {
+}