SD.open()返回true，但不创建文件 [英] SD.open() returns true but does not create a file

问题描述

我正面临SD卡和Arduino的特定问题.我想创建一个功能，以在另一天的SD卡上创建一个新文件.现在，我正在用int模拟日历.我知道这个问题已经讨论过了，但是我似乎找不到类似讨论的问题.

I'm facing a specific problem with SD card and Arduino. I want to create a function that creates a new file on the SD card for a different day. For now, I'm simulating calendar with ints. I know that problem was already discussed but I can't seem to find a similarly discussed problem.

代码:

#include <stdlib.h> // included for floatToString 
#include <math.h> 
#include <SPI.h>
#include <SD.h>

int year = 2014;
int month = 11;
int day = 4;

char dateTitle[20]; //= "0000000000.txt";

void printDateTitle(char* dateTitle, int Y, int M, int D){
  //char dateTitle[20];
  sprintf(dateTitle, "%4d-%02d-%02d.txt", Y, M, D);
  return;
}

const int chipSelect = 4;

void setup() {
  //printDateTitle(dateTitle, year, month, day);
  Serial.begin(9600);
  while (!Serial) {
    ;
  }
  Serial.print("Initializing SD card...");
  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present");
    while (1);
  }
  Serial.println("card initialized.");
}

void loop() {
  Serial.print(dateTitle);
  delay(1000);
  File dataFile = SD.open(dateTitle, FILE_WRITE);
  if (dataFile){
    dataFile.println("something");
    dataFile.close();
    Serial.print(day);
    Serial.println("something");
    delay(1000);
  } else 
    Serial.println("Error");
}

在代码中，我有一个函数 void printDateTitle ，该函数将日历中的输入格式化为要用作文件标题的字符串.

In the code, I have a function void printDateTitle that formats the inputs from the calendar to string which I want to use as a title for the file.

而且，当我在 void loop()中用 printDateTitle(dateTitle，year，month，day)定义函数时，输出含义SD.open = false.

And also, when I define a function in the void loop() with printDateTitle(dateTitle, year, month, day); I get an "Error" in the output meaning SD.open = false.

问题在于，即使SD.open返回true，它也不会在SD卡上创建文件..txt包含在char数组中.我也用大写的.TXT.

The problem is that even though SD.open returns true it doesn't create a file on the SD card. .txt is included in the char array. I have also used capital .TXT.

对于有关该问题的所有建议，我将不胜感激.

I would be grateful for all the bits of advice regarding the problem.

作为参考，我使用Arduino Uno和

For the reference, I'm using Arduino Uno and Micro SD card Adapter with Arduino IDE.

推荐答案

Arduino SD库文档指出它使用文件的短8.3名称".因此，只有名称为8个字符且文件扩展名为3个字符的文件有效.例如:12345678.txt有效，123456789.txt无效.

The Arduino SD Library documentation states that it uses the "short 8.3 names for files". Therefore only files with 8 characters as name and 3 for file extension are valid. For example: 12345678.txt is valid, 123456789.txt would be invalid.

您的日期字符串(2014-11-04.txt)太长，因为它有10个字符，而不是8个字符.

Your date string (2014-11-04.txt) is to long because it has 10 characters instead of only 8.

还要确保已将SD卡格式化为FAT16或FAT32文件系统.

Also make sure you've formatted the SD card to a FAT16 or FAT32 file system.

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