updated SD examples with new constants, and commented them

tigoe · tigoe · commit 86e3d4ad7a41 · 2010-12-03T10:35:17.000-05:00
diff --git a/libraries/SD/examples/Datalogger/Datalogger.pde b/libraries/SD/examples/Datalogger/Datalogger.pde
@@ -13,6 +13,7 @@
  ** CS - pin 4
  
  created  24 Nov 2010
+ updated 2 Dec 2010
  by Tom Igoe
  
  This example code is in the public domain.
@@ -31,8 +32,9 @@ void setup()
 {
   Serial.begin(9600);
   Serial.print("Initializing SD card...");
-  
-  pinMode(10, OUTPUT);
+  // make sure that the default chip select pin is set to
+  // output, even if you don't use it:
+ // pinMode(10, OUTPUT);
   
   // see if the card is present and can be initialized:
   if (!SD.begin(chipSelect)) {
@@ -58,7 +60,7 @@ void loop()
   }
 
   // open the file:
-  File dataFile = SD.open("datalog.txt", true, true);
+  File dataFile = SD.open("datalog.txt", FILE_APPEND);
 
   // if the file is available, write to it:
   if (dataFile) {
diff --git a/libraries/SD/examples/Files/Files.pde b/libraries/SD/examples/Files/Files.pde
@@ -1,40 +1,76 @@
+/*
+  SD card basic file example
+ 
+ This example shows how to create and destroy an SD card file 	
+ The circuit:
+ * SD card attached to SPI bus as follows:
+ ** MOSI - pin 11
+ ** MISO - pin 12
+ ** CLK - pin 13
+ ** CS - pin 4
+ 
+ created   Nov 2010
+ by David A. Mellis
+ updated 2 Dec 2010
+ by Tom Igoe
+ 
+ This example code is in the public domain.
+ 	 
+ */
 #include <SD.h>
 
-File f;
+File myFile;
 
 void setup()
 {
   Serial.begin(9600);
   Serial.print("Initializing SD card...");
-  // On the Ethernet Shield, CS is pin 4. Note that even if it's not
-  // used as the CS pin, the hardware SS pin (10 on most Arduino boards,
-  // 53 on the Mega) must be left as an output or the SD library
-  // functions will not work.
+  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
+  // Note that even if it's not used as the CS pin, the hardware SS pin 
+  // (10 on most Arduino boards, 53 on the Mega) must be left as an output 
+  // or the SD library functions will not work. 
+
   if (!SD.begin(4)) {
-    Serial.println("failed!");
+    Serial.println("initialization failed!");
     return;
   }
-  Serial.println("done.");
-  
-  if (SD.exists("example.txt")) Serial.println("example.txt exists.");
-  else Serial.println("example.txt doesn't exist.");
+  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...");
-  f = SD.open("example.txt", true);
-  f.close();
+ myFile = SD.open("example.txt", FILE_TRUNCATE);
+ myFile.close();
   
-  if (SD.exists("example.txt")) Serial.println("example.txt exists.");
-  else Serial.println("example.txt doesn't exist.");  
+  // 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.");  
+  if (SD.exists("example.txt")){ 
+  	Serial.println("example.txt exists.");
+  }
+  else {
+  	Serial.println("example.txt doesn't exist.");  
+  }
 }
 
 void loop()
 {
+	// nothing happens after setup finishes.
 }
 
 
diff --git a/libraries/SD/examples/ReadWrite/ReadWrite.pde b/libraries/SD/examples/ReadWrite/ReadWrite.pde
@@ -1,43 +1,77 @@
+/*
+  SD card read/write
+ 
+ This example shows how to read and write data to and from an SD card file 	
+ The circuit:
+ * SD card attached to SPI bus as follows:
+ ** MOSI - pin 11
+ ** MISO - pin 12
+ ** CLK - pin 13
+ ** CS - pin 4
+ 
+ created   Nov 2010
+ by David A. Mellis
+ updated 2 Dec 2010
+ by Tom Igoe
+ 
+ This example code is in the public domain.
+ 	 
+ */
+ 
 #include <SD.h>
 
-File f;
+File myFile;
 
 void setup()
 {
   Serial.begin(9600);
   Serial.print("Initializing SD card...");
-  // On the Ethernet Shield, CS is pin 4. Note that even if it's not
-  // used as the CS pin, the hardware SS pin (10 on most Arduino boards,
-  // 53 on the Mega) must be left as an output or the SD library
-  // functions will not work.
+  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
+  // Note that even if it's not used as the CS pin, the hardware SS pin 
+  // (10 on most Arduino boards, 53 on the Mega) must be left as an output 
+  // or the SD library functions will not work. 
+    
   if (!SD.begin(4)) {
-    Serial.println("failed!");
+    Serial.println("initialization failed!");
     return;
   }
-  Serial.println("done.");
+  Serial.println("initialization done.");
   
-  f = SD.open("test.txt", true, false);
-  if (f) {
+  // open a file:
+  myFile = SD.open("test.txt", FILE_TRUNCATE);
+  
+  // if the file opened okay, write to it:
+  if (myFile) {
     Serial.print("Writing to test.txt...");
-    f.println("testing 1, 2, 3.");
-    f.close();
+    myFile.println("testing 1, 2, 3.");
+	// close the file:
+    myFile.close();
     Serial.println("done.");
   } else {
+    // if the file didn't open, print an error:
     Serial.println("error opening test.txt");
   }
   
-  f = SD.open("test.txt");
-  if (f) {
+  // re-open the file for reading:
+  myFile = SD.open("test.txt");
+  if (myFile) {
     Serial.println("test.txt:");
-    while (f.available()) Serial.write(f.read());
-    f.close();
+    
+    // read from the file until there's nothing else in it:
+    while (myFile.available()) {
+    	Serial.write(myFile.read());
+    }
+    // close the file:
+    myFile.close();
   } else {
+  	// if the file didn't open, print an error:
     Serial.println("error opening test.txt");
   }
 }
 
 void loop()
 {
+	// nothing happens after setup
 }
 
 
