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3 years, 10 months ago.

reading from flash memory of K64f

Hi all, Finally I managed to write the data into flash memory of K64f. Thanks to the following link: https://developer.mbed.org/users/Sissors/code/FreescaleIAP/

The issue is I am struggling to read the code from the memory. If I write and read from the memory int the same program, every things work fine. But when I tries to write the data from one program and try to read it from different program, it gives me the null value. for example if I run the following code

  int address = flash_size() - SECTOR_SIZE;           //Write in last sector
    
    int *data = (int*)address;
    printf("Starting\r\n"); 
    erase_sector(address);
    int numbers[10] = {0, 1, 10, 100, 1000, 10000, 1000000, 10000000, 100000000, 1000000000};
    program_flash(address, (char*)&numbers, 40);        //10 integers of 4 bytes each: 40 bytes length
    printf("Resulting flash: \r\n");
    for (int i = 0; i<10; i++)
        printf("%d\r\n", data[i]);
    
    printf("Done\r\n\n");
        

It gives me the correct output. But when I just try to read the values from different program it dont display the output/

// code for reading
int address = flash_size() - SECTOR_SIZE;           //Write in last sector
    
    int *data = (int*)address;
    printf("Starting\r\n"); 
  //  erase_sector(address);  do not erase the previous content
   // int numbers[10] = {0, 1, 10, 100, 1000, 10000, 1000000, 10000000, 100000000, 1000000000};
   // program_flash(address, (char*)&numbers, 40);        //dont overwrite the previous data
    printf("Resulting flash: \r\n");
    for (int i = 0; i<10; i++)
        printf("%d\r\n", data[i]);     //display the non volatile data
    
    printf("Done\r\n\n");
        

The read code doesnt show any output rather it gives me -1 means it doesnt have any thing to display.

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1 Answer

3 years, 10 months ago.

I am pretty sure this happens because the interface chip most likely issues a full chip erase before programming, removing the programmed values again. So either you need to program it with a different method (maybe CMSIS-DAP programmer does not do it), or stick to using it to store data between resets/no power situations.

Yes you are right... we need to develop a algorithm that it has to read and write in a single program

  int address = flash_size() - SECTOR_SIZE;           //Write in last sector
    
    char *data = (char*)address;
   for (int i = 0; i<11; i++)
        printf(" %c ", data[i]);       // it will not run for the initial setup, but it will print data
                                                // for the subsequent bootups
//if (data) 
// call function  to print stored data
  
    printf(" \n Starting\r\n"); 
    erase_sector(address);
    char *store="192.168.0.2";
    program_flash(address, store, 12);        //10 integers of 4 bytes each: 40 bytes length
    printf("Resulting flash: \r\n");
    printf("stored data %s\r\n", data);
    printf("Done\r\n\n");
    printf("stored data %s\r\n", data);


posted by zain aftab 01 Jun 2015

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