80 lines
1.7 KiB
Arduino
80 lines
1.7 KiB
Arduino
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/*
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SD card read/write
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This example shows how to read and write data to and from an SD card file
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The circuit:
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SD card attached to SPI bus as follows:
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** MOSI - pin 11
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** MISO - pin 12
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** CLK - pin 13
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** CS - pin 4 (for MKRZero SD: SDCARD_SS_PIN)
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created Nov 2010
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by David A. Mellis
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modified 9 Apr 2012
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by Tom Igoe
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This example code is in the public domain.
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*/
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#include <SPI.h>
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#include <SD.h>
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File myFile;
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void setup() {
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// Open serial communications and wait for port to open:
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Serial.begin(9600);
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while (!Serial) {
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; // wait for serial port to connect. Needed for native USB port only
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}
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Serial.print("Initializing SD card...");
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if (!SD.begin(4)) {
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Serial.println("initialization failed!");
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while (1);
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}
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Serial.println("initialization done.");
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// open the file. note that only one file can be open at a time,
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// so you have to close this one before opening another.
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myFile = SD.open("test.txt", FILE_WRITE);
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// if the file opened okay, write to it:
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if (myFile) {
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Serial.print("Writing to test.txt...");
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myFile.println("testing 1, 2, 3.");
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// close the file:
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myFile.close();
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Serial.println("done.");
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} else {
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// if the file didn't open, print an error:
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Serial.println("error opening test.txt");
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}
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// re-open the file for reading:
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myFile = SD.open("test.txt");
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if (myFile) {
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Serial.println("test.txt:");
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// read from the file until there's nothing else in it:
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while (myFile.available()) {
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Serial.write(myFile.read());
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}
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// close the file:
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myFile.close();
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} else {
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// if the file didn't open, print an error:
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Serial.println("error opening test.txt");
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}
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}
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void loop() {
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// nothing happens after setup
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}
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