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发表于 2016-9-17 19:17:40
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本帖最后由 zjz5717 于 2016-9-17 19:18 编辑
- /*
- 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
- modified 9 Apr 2012
- by Tom Igoe
- This example code is in the public domain.
- */
- #include <SPI.h>
- #include <SD.h>
- File myFile;
- String a="test.txt";
- void setup() {
- // Open serial communications and wait for port to open:
- Serial.begin(9600);
- while (!Serial) {
- ; // wait for serial port to connect. Needed for native USB port only
- }
- Serial.print("Initializing SD card...");
- 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(a, 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
- }
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pen(const char *filepath, uint8_t mode)
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