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SD fat32 write problem

 
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kalambraka



Joined: 24 Jan 2012
Posts: 4

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SD fat32 write problem
PostPosted: Tue Jan 24, 2012 10:37 pm     Reply with quote

Hi guys!

I'm interfacing a PIC18F2455 with a SD card using the mmc_spi_fat32.c library.

I send data coming from sensors to the card using the fwrite function, and then I can see it (so, it's seems that everything is OK), but I realize that it only writes the half of my data into the card. If I send 4 datas using fwrite I can only see 2 in the card. If I send 8, I see 4...

I write this test program sending the data in a loop:

Code:

#include <18F2455.h>


#use delay(clock=4000000)

#include "mmc_spi_fat32.h"


#include <usb_cdc.h>
#include <string.h>
#include "mmc_spi_fat32.c"




#ZERO_RAM
void main(){
  delay_ms(1000);
  char file,gfilename[5];
  int t[3];
  int h[3];
  int p[3];
  int l=3,x=1;
  int mesura=0;
 
   
  usb_cdc_init();
  usb_init();
 
 
  while(!usb_cdc_connected()) {}         // Espera fins detectar una transmisió USB
 
  if (usb_enumerated()){                 // El PC reconeix el dispositiu
 
   usb_task();
 
   delay_ms(1000);
   
 

      MMCInit() == MMC_OK;
    while(MMCInit() != MMC_OK){ //espera inicialitzacio
      printf(usb_cdc_putc,"MMC init FAIL!!!!!\r\n");
      printf(usb_cdc_putc,"Try again...\r\n");
      delay_ms(100);
      MMCInit() == MMC_OK;
    }
      printf(usb_cdc_putc,"MMC init OK!!!!!\r\n"); 
      delay_ms(1000);
      InitFAT();
      printf(usb_cdc_putc,"FAT init OK!!!!!\r\n");
      delay_ms(1000);
      strcpy(gfilename,"D.LOG"); 
       
     
       
      file = fopen(gfilename,'w'); // open EVENTS.LOG for append      ////
      if (file & MMC_ERROR)                                           ////
      {                                                            ////
         printf(usb_cdc_putc,"Couldn't open file!\r\n");                        ////
            if(file == MMC_NO_CARD_INSERTED)                             ////
               printf(usb_cdc_putc,"Please, insert MMC!");                         ////
            else if(file == MMC_MAX_FILES_REACHED)                       ////
               printf(usb_cdc_putc,"ops.. =)");                                    ////
    }                                                            ////
    else                                                         ////
    {
   
//#ZERO_RAM
DELAY_MS(1000);

 t[0]=02;
 t[1]=02;
 t[2]=02;

   
  h[0]=03;
  h[1]=03;
  h[2]=03;
 
 
  p[0]=04;
  p[1]=04;
  p[2]=04;

   while(mesura<4){
     
     
      printf(usb_cdc_putc,"Start writing...\r\n");

 
      fwrite(t,l,file);
      delay_ms(10);

      fwrite(h,l,file);
      delay_ms(10);

      fwrite(p,l,file);
      delay_ms(10);


      delay_ms(10);
           
      fclose(file);
      delay_ms(10);
      delay_ms(100);
 
      printf(usb_cdc_putc,"Write complete...");
      mesura=mesura+1;
      }
     
      delay_ms(100);
    }             
     
  }
 
 
 
}
 


In the SD card I should see:
222333444
222333444
222333444
222333444

but I always see only half:
222333444
222333444

Can anyone help me?

Thank you.
Ttelmah



Joined: 11 Mar 2010
Posts: 19545

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PostPosted: Wed Jan 25, 2012 2:23 am     Reply with quote

I'm surprised you see half.
Don't you think the fact that you have closed the file after writing the first 9 bytes, and don't open it again, might have something to do with it.

Best Wishes
kalambraka



Joined: 24 Jan 2012
Posts: 4

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PostPosted: Wed Jan 25, 2012 11:55 am     Reply with quote

Thanks for the reply.

If I open again the file inside the loop, then I see nothing in the SD card...
It's really strange...

The only solution that I found is sending data with zeros in another loop after this... I think that maybe it's something related to cleaning the buffer afer writing again...
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