SDIO and SD fat access example?

[natblist]

Posted on February 09, 2012 at 01:06

Hi Chaps,

Going slowly mad trying to get Chan Fat working with the sdio libs on a stm32f4.I'm using the most recent (1.0.0) library for the F4, and the low level access demo within that library builds and (at least appears to ) work OK. I've spent many, many hours attempting to patch in 0.9 version of fatfs from chan (thks chan, you're a hero) - but I can't get it to work.If possible, I'd really really appreciate a demo project/source (or direction to - though I've scoured the web and can't find anything that works!)I'll post separately about the current problems I'm having with the my current build, but a working example would sort it.Many thanks,nat. #hse-sdio-stm32 #stm32-fat-chanfat-fatfs-sdio #sdcard-stm32f4-sdio-fatfs #sdcard-stm32f4-sdio-fatfs

[cleonb322]

Posted on September 19, 2016 at 22:52

If I closed a file and then reopen it, I cannot write more data to it after reopening it, but if i keep it open i can write as many lines as i want then close it after i am finished writing. Does anyone have a similar issue withe ELM Chang's FATFS?

See the example below. Thanks. if (f_mount(&FatFs, '''', 1) == FR_OK) { f_mkdir (''TEST''); count = 0; while(count < 200){ if(f_open(&fil, ''TEST/test.txt'', FA_OPEN_ALWAYS | FA_WRITE) != FR_OK){ break; } else{ sprintf(array,''This is file entry number: %d '',count); f_puts(array, &fil); if(f_close(&fil) != FR_OK){ break; } } count++; } f_mount(0, '''', 1); }

http://stackoverflow.com/questions/39560704/elm-changs-fatfs#

If I close a file and then reopen it, I cannot write more data to it after reopening it, but if i keep it open i can write as many lines as i want then close it when i am finish writing. See the example below. Thanks.

if (f_mount(&FatFs, '''', 1) == FR_OK) { f_mkdir (''TEST''); count = 0; while(count < 200){ if(f_open(&fil, ''TEST/test.txt'', FA_OPEN_ALWAYS | FA_WRITE) != FR_OK){ break; } else{ sprintf(array,''This is file entry number: %d

'',count); f_puts(array, &fil); if(f_close(&fil) != FR_OK){ break; } } count++; } f_mount(0, '''', 1);}

[cleonb322]

Posted on September 19, 2016 at 23:03

@clive 

If I close a file and then reopen it, I cannot write more data to it after reopening it. Does anyone have this problem? if I execute the following code it will not save all the lines, it will save only the last line of data. if (f_mount(&FatFs, '''', 1) == FR_OK) {      f_mkdir (''TEST'');      count = 0;      while(count < 200){          if(f_open(&fil, ''TEST/test.txt'', FA_OPEN_ALWAYS | FA_WRITE) != FR_OK){              break;          }          else{              sprintf(array,''This is file entry number: %d\r\n'',count);              f_puts(array, &fil);              if(f_close(&fil) != FR_OK){                  break;              }          }          count++;      }      f_mount(0, '''', 1);}

[Tesla DeLorean]

Posted on September 20, 2016 at 01:08, cleaned up messy forum transition 6-May-2023

Seek to the end of the file

...
// Incremental write test, appending to end-of-file
if (f_open(&fil, "LOG.TXT", FA_OPEN_ALWAYS | FA_WRITE) == FR_OK)
{
  UINT BytesWritten;
  const char string[] = "Another line gets added";
  f_lseek(&fil, fil.fsize); // newer perhaps f_size(&fil) macro?
  f_write(&fil, string, strlen(string), &BytesWritten);
  f_close(&fil);
}

[sameena shaikh]

Posted on October 23, 2017 at 12:08

Hi,

Can you tell me how do you measure the writing speed to ur sd card???

Thanks & Regards

Sameena Shaikh

[Tesla DeLorean]

BYPASS is problematic on the F2/F4 implementations. ST want's you to use at least a DIV2 of the clock. However you can clock the SDIO peripheral from a 75 MHz PLL clock getting you 37.5 MHz on the bus. Problem then is that USB and CRYP don't work as wrong speed, and too fast.