trunk/Arduino/libraries/SD/examples/ReadWrite/ReadWrite.ino

@@ -2,41 +2,44 @@
   SD card read/write
 
   This example shows how to read and write data to and from an SD card file
-  The circuit:
+  The circuit. Pin numbers reflect the default
+  SPI pins for Uno and Nano models:
    SD card attached to SPI bus as follows:
- ** MOSI - pin 11
- ** MISO - pin 12
+ ** SDO - pin 11
+ ** SDI - pin 12
  ** CLK - pin 13
- ** CS - pin 4 (for MKRZero SD: SDCARD_SS_PIN)
+ ** CS - pin 4 (For For Uno, Nano: pin 10. For MKR Zero SD: SDCARD_SS_PIN)
 
   created   Nov 2010
   by David A. Mellis
-  modified 9 Apr 2012
+  modified  24 July 2020
   by Tom Igoe
 
   This example code is in the public domain.
 
 */
-
-#include <SPI.h>
 #include <SD.h>
 
+const int chipSelect = 10;
 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 native USB port only
-  }
-
+  // wait for Serial Monitor to connect. Needed for native USB port boards only:
+  while (!Serial);
 
   Serial.print("Initializing SD card...");
 
-  if (!SD.begin(4)) {
-    Serial.println("initialization failed!");
-    while (1);
+  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,
@@ -75,5 +78,3 @@ void setup() {
 void loop() {
   // nothing happens after setup
 }
-
-