在 SD 卡上保存文件时出错

Question

我正在使用带有 Arduino 分线板的英特尔 Edison。我想将文件保存在 SD 卡上，并在 Arduino IDE 上运行一个简单的 ReadWrite 示例。一切正常，我得到了输出：

正在初始化 SD 卡...初始化完成。写给 test.txt ...完成。 test.txt：测试 1、2、3。

但是当我将 SD 卡插入 PC 时，文件不存在或为空。

这是示例代码：

#include <SPI.h>
#include <SD.h>

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 Leonardo only
  }


  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
}

Answer 1

我用这个命令卸载

umount /media/sdcard

它解决了这个问题。