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LMI2
LMI2
Senior III
June 5, 2018
Solved

Any examples with f_findfirst/f_findnext for 746D?

  • June 5, 2018
  • 11 replies
  • 3339 views
Posted on June 05, 2018 at 17:23

ST seems to do reading all files in a directory in a hard way.

I am combining two examples about Sdfat but ST uses unfamiliar commands for reading all files in a directory. I think I could do it with a hard way but isn't f_findfirst/f_findnext more common.

I have examples for reading all bmp files and an other showing one jpg file.

Edit: By the way. I still have to accept cookies several times in one session.

    This topic has been closed for replies.
    Best answer by Tesla DeLorean
    Posted on June 05, 2018 at 23:03

    In ffconf.h

    ♯ define _USE_FIND        1

    /* This option switches filtered directory read functions, f_findfirst() and

    /  f_findnext(). (0:Disable, 1:Enable 2:Enable with matching altname[] too) */

    They compile a short list, in much the same way as you might populate the entries in a COMBO_BOX, in much the same way I'd display a list of Firmware .BIN files and ask the user to pick one, then I can load the selected one immediately rather than enumerate the files. The latter being problematic in a multi-tasking system where new files could appear, or old ones get deleted, and the indexes would change.

    11 replies

    Tesla DeLorean
    Tesla DeLorean
    Guru
    June 5, 2018
    Posted on June 05, 2018 at 17:47

    >>Any examples with f_findfirst/f_findnext for 746D?

    Why make this F746 or STM32 specific, FatFS is platform agnostic.

    Is there an issue with this example?

    http://elm-chan.org/fsw/ff/doc/findfirst.html

     

    >>ST uses unfamiliar commands for reading all files in a directory.

    Ok, but what does that mean, unfamiliar to them, to you, others practiced in the art?

    STM32Cube_FW_F7_V1.11.0\Projects\STM32746G-Discovery\Applications\Display\LTDC_PicturesFromSDCard\Src\fatfs_storage.c

    /**

      * @brief  List up to 25 file on the root directory with extension .BMP

      * @param  None

      * @retval The number of the found files

      */

    uint32_t Storage_GetDirectoryBitmapFiles (const char* DirName, char* Files[])

    {

      FRESULT res;

      uint32_t index = 0;

      /* Open filesystem */

      if(f_mount(&fs, (TCHAR const*)'',0) != FR_OK)

      {

        return 0;

      }

      /* Start to search for wave files */

      res = f_findfirst(&dir, &fno, DirName, '*.bmp');

      /* Repeat while an item is found */

      while (fno.fname[0])

      {

        if(res == FR_OK)

        {

          if(index < MAX_BMP_FILES)

          {

            sprintf (Files[index++], '%s', fno.fname);

          }

          /* Search for next item */

          res = f_findnext(&dir, &fno);

        }

        else

        {

          index = 0;

          break;

        }

      }

      f_closedir(&dir);

      return index;

    }

    >>By the way. I still have to accept cookies several times in one session.

    Some settings or plug-ins at your end, this isn't an issue for 99.99% of users here. If it becomes sufficiently annoying, then change your behaviour.

    Tips, Buy me a coffee, or three.. PayPal Venmo (See Profile) Up vote any posts that you find helpful, it shows what's working..
    LMI2
    LMI2Author
    Senior III
    June 5, 2018
    Posted on June 05, 2018 at 22:41

    My C or Sdfat skills are in no way perfect. I get this error just inserting the function

    'STM32746G-DISCOVERY\Exe\Project.axf: Error: L6218E: Undefined symbol f_findfirst (referred from main.o).' and same from findnext. I use STM32Cube_FW_F7_V1.11.0\Projects\STM32746G-Discovery\Applications\LibJPEG as basis, it uses Sdfat but clearly something is missing.

    >>ST uses unfamiliar commands for reading all files in a directory.

    'Ok, but what does that mean, unfamiliar to them, to you, others practiced in the art?'

    I wonder what is the reason not using f_findnext. I have probably used them elsewhere and it was easy enough I think. Having an array to store file names eats ram.

    Tilen MAJERLE
    Tilen MAJERLE
    ST Employee
    June 5, 2018
    Posted on June 05, 2018 at 22:48

    Hello

    Michael.Lei

    ‌,

    follow FatFS docs and you will see how to enable f_findfirst/next functions:

    http://elm-chan.org/fsw/ff/doc/findfirst.html

    Best regard,

    Tilen

    LMI2
    LMI2Author
    Senior III
    June 5, 2018
    Posted on June 06, 2018 at 01:15

    The code combiled without errors. That

    'In ffconf.h

    #define _USE_FIND        1->0 helped. But I don't want edit shared include files. I have to do some testing still, copy the file in my main.c folder probably. It is also getting late here,I'll continue tomorrow.

    I thank you Clive and Tilen. This is much better now.

    Edit: ffconf.h is project specific in this project, no need to fear about messing other projects

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