Merge pull request #295 from UniquePete/patch-2

Create ReadWrite.ino

Author: Heltec-Aaron-Lee

libraries/Basics/examples/SD/ReadWrite.ino

@@ -0,0 +1,67 @@
+/*
+  SD card read/write
+
+  SD card reader attached to SPI1 bus as follows:
+ ** MOSI1 - GPIO1
+ ** MISO1 - GPIO2
+ ** CLK1  - GPIO3
+ ** CS1   - GPIO4
+*/
+
+#include <SPI.h>
+#include <SD.h>
+
+#define CS1 GPIO4
+
+File myFile;
+
+void setup() {
+  // Open serial communications and wait for port to open:
+  Serial.begin(115200);
+  
+  SPI1.begin(SCK1, MISO1, MOSI1, CS1);
+
+  Serial.print("Initializing SD card...");
+
+  if (!SD.begin(CS1)) {
+    Serial.println("failed!");
+    while (1);
+  }
+  Serial.println("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.
+  myFile = SD.open("test.txt", FILE_WRITE);
+
+  // if the file opened okay, write to it:
+  if (myFile) {
+    Serial.print("Writing to test.txt...");
+    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 to write!");
+  }
+  delay(1000);
+  // re-open the file for reading:
+  myFile = SD.open("test.txt");
+  if (myFile) {
+    Serial.println("test.txt:");
+
+    // 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 to read!");
+  }
+}
+
+void loop() {
+  // nothing happens after setup
+}