[136] | 1 | /*
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| 2 | SD card basic file example
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| 3 |
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| 4 | This example shows how to create and destroy an SD card file
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| 5 | The circuit:
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| 6 | * SD card attached to SPI bus as follows:
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| 7 | ** MOSI - pin 11
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| 8 | ** MISO - pin 12
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| 9 | ** CLK - pin 13
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| 10 | ** CS - pin 4
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| 11 |
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| 12 | created Nov 2010
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| 13 | by David A. Mellis
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| 14 | modified 9 Apr 2012
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| 15 | by Tom Igoe
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| 16 |
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| 17 | This example code is in the public domain.
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| 18 |
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| 19 | */
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| 20 | #include <SPI.h>
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| 21 | #include <SD.h>
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| 22 |
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| 23 | File myFile;
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| 24 |
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| 25 | void setup()
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| 26 | {
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| 27 | // Open serial communications and wait for port to open:
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| 28 | Serial.begin(9600);
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| 29 | while (!Serial) {
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| 30 | ; // wait for serial port to connect. Needed for Leonardo only
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| 31 | }
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| 32 |
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| 33 |
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| 34 | Serial.print("Initializing SD card...");
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| 35 | // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
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| 36 | // Note that even if it's not used as the CS pin, the hardware SS pin
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| 37 | // (10 on most Arduino boards, 53 on the Mega, 14 on the Leonardo) must be left as an output
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| 38 | // or the SD library functions will not work.
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| 39 |
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| 40 | if (!SD.begin(4)) {
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| 41 | Serial.println("initialization failed!");
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| 42 | return;
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| 43 | }
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| 44 | Serial.println("initialization done.");
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| 45 |
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| 46 | if (SD.exists("example.txt")) {
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| 47 | Serial.println("example.txt exists.");
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| 48 | }
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| 49 | else {
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| 50 | Serial.println("example.txt doesn't exist.");
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| 51 | }
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| 52 |
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| 53 | // open a new file and immediately close it:
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| 54 | Serial.println("Creating example.txt...");
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| 55 | myFile = SD.open("example.txt", FILE_WRITE);
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| 56 | myFile.close();
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| 57 |
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| 58 | // Check to see if the file exists:
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| 59 | if (SD.exists("example.txt")) {
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| 60 | Serial.println("example.txt exists.");
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| 61 | }
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| 62 | else {
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| 63 | Serial.println("example.txt doesn't exist.");
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| 64 | }
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| 65 |
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| 66 | // delete the file:
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| 67 | Serial.println("Removing example.txt...");
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| 68 | SD.remove("example.txt");
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| 69 |
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| 70 | if (SD.exists("example.txt")) {
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| 71 | Serial.println("example.txt exists.");
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| 72 | }
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| 73 | else {
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| 74 | Serial.println("example.txt doesn't exist.");
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| 75 | }
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| 76 | }
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| 77 |
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| 78 | void loop()
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| 79 | {
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| 80 | // nothing happens after setup finishes.
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| 81 | }
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| 82 |
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| 83 |
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| 84 |
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