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Diffstat (limited to 'libraries/SD/examples/ReadWrite/ReadWrite.ino')
-rw-r--r-- | libraries/SD/examples/ReadWrite/ReadWrite.ino | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/libraries/SD/examples/ReadWrite/ReadWrite.ino b/libraries/SD/examples/ReadWrite/ReadWrite.ino new file mode 100644 index 0000000..9957218 --- /dev/null +++ b/libraries/SD/examples/ReadWrite/ReadWrite.ino @@ -0,0 +1,79 @@ +/* + 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 myFile; + +void setup() +{ + Serial.begin(9600); + Serial.print("Initializing SD card..."); + // 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. + pinMode(10, OUTPUT); + + if (!SD.begin(4)) { + Serial.println("initialization failed!"); + return; + } + 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. + 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"); + } + + // 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"); + } +} + +void loop() +{ + // nothing happens after setup +} + + |