| /* | |
| 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 (for MKRZero SD: SDCARD_SS_PIN) | |
| created Nov 2010 | |
| by David A. Mellis | |
| modified 9 Apr 2012 | |
| by Tom Igoe | |
| This example code is in the public domain. | |
| */ | |
| File myFile; | |
| 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!"); | |
| while (1); | |
| } | |
| 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 | |
| } | |