RewindDirectory() does not bring the file back to the top.

The development environment is Arduino.

We had them run a program similar to the following, but after running rewindDirectory(), we went through the file name acquisition for the second time.
Is there something wrong?
Or is it a phenomenon that depends on the SD card?
Please let me know.

Also, the number of files recognized is up to 9 (actually 13 files exist).
Is there a limit to the number of files?

//For SPRESENSE
# include <SDHCI.h>
SDClass SD;
constuint8_tcs_SD=5;

char Mp3Name [128];

File theSD;
File entry;
File root;
void setup()
{
intnk = 0;
Serial.begin (115200);
SD.begin();

// SD Card File Name Acquisition Experiment
root=SD.open("/");
while(true)
{
entry=root.openNextFile();
if(!entry)
{
// If there are no more files
root.rewindDirectory();
usleep(40000);
break;
}

    // If it is not a directory name
    if(!entry.isDirectory()) 
    {
        String fileName=entry.name();
        strcpy(Mp3Name, & fileName[0]);
        nk++;
        printf("[%02d]%s\n", nk, Mp3Name);
    }
}
nk = 0;
while(true) 
{
    entry=root.openNextFile();
    if(!entry)
    {
        // If there are no more files
        root.rewindDirectory();
        usleep(40000);
        break;
    }

    // If it is not a directory name
    if(!entry.isDirectory()) 
    {
        String fileName=entry.name();
        strcpy(Mp3Name, & fileName[0]);
        nk++;
        printf("[%02d]%s\n", nk, Mp3Name);
    }
}
printf("SetupEnd\n";

}

void loop() {
// put your main code here, to run repeatly:

}

spresense

2022-09-30 21:53

1 Answers

I've been into the same problem.

At the end of File entry=dir.openNextFile();, close the file with entry.close();.I'm sure you're stuck with the maximum number of files you can open (estimated)

I was wondering why SDHCI's sample sketch UsbMscAndFileOperation.ino works, and I noticed it while looking at the difference.

Try it.

//For SPRESENSE
# include <SDHCI.h>
SDClass SD;
constuint8_tcs_SD=5;

char Mp3Name [128];

File theSD;
File entry;
File root;
void setup()
{
  intnk = 0;
  Serial.begin (115200);
  SD.begin();

  // SD Card File Name Acquisition Experiment
  root=SD.open("/");
  while(true)
    {
      entry=root.openNextFile();
      if(!entry)
        {
          // If there are no more files
          root.rewindDirectory();
          usleep(40000);
          break;
        }

      // If it is not a directory name
      if(!entry.isDirectory())
        {
          String fileName=entry.name();
          strcpy(Mp3Name, & fileName[0]);
          nk++;
          printf("[%02d]%s\n", nk, Mp3Name);
        }
      entry.close();//★★Add★★
    }
  nk = 0;
  while(true)
    {
      entry=root.openNextFile();
      if(!entry)
        {
          // If there are no more files
          root.rewindDirectory();
          usleep(40000);
          break;
        }

      // If it is not a directory name
      if(!entry.isDirectory())
        {
          String fileName=entry.name();
          strcpy(Mp3Name, & fileName[0]);
          nk++;
          printf("[%02d]%s\n", nk, Mp3Name);
        }
      entry.close();//★★Add★★
    }
  printf("SetupEnd\n";

}

void loop() {
// put your main code here, to run repeatly:

}

2022-09-30 21:53

If you have any answers or tips

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