I need to take backup of my FLASH before writing the FIRMWARE to my STM32F411CEUx.

I have written a test program for reading initial 1024 bytes (1KB) of my bootloader program itself and writing to binary file in PC to check my program’s correctness.

Communication parameters:

BaudRate = 9600

Parity = NONE

Stop bit = 1

Flow control = NONE

Problem:

1. On comparing the binary files loaded in micro controller and this backup binary file, there is difference on BYTE 0x198 till 8 bytes (compared using STLINK Utility).

   

I checked the outputs of both the programs and they are printing identical. Below is the debug prints from both PC as well as STM32

PC TOOL output:

Address [00000188] : 0x 00 00 00 00
Address [0000018C] : 0x 00 00 00 00
Address [00000190] : 0x D1 0B 00 08
Address [00000194] : 0x D1 0B 00 08
Address [00000198] : 0x FF FF FF FF
Address [0000019C] : 0x FF FF FF FF
Address [000001A0] : 0x 10 B5 05 4C
Address [000001A4] : 0x 23 78 33 B9
Address [000001A8] : 0x 04 4B 13 B1
Address [000001AC] : 0x 04 48 AF F3

STM32 output:

Address [00000188] : 0x 00 00 00 00
Address [0000018C] : 0x 00 00 00 00
Address [00000190] : 0x D1 0B 00 08
Address [00000194] : 0x D1 0B 00 08
Address [00000198] : 0x FF FF FF FF
Address [0000019C] : 0x FF FF FF FF
Address [000001A0] : 0x 10 B5 05 4C
Address [000001A4] : 0x 23 78 33 B9
Address [000001A8] : 0x 04 4B 13 B1
Address [000001AC] : 0x 04 48 AF F3

Please help on where I am missing, Thank you 🙂

Attached code of program on PC side is attached here

Code on my STM32F411CEUx is as below:

bool BackupFlashApp()
{
    int i=0;
    unsigned int bytes_to_read=1024;
    unsigned int dataindex=0;
    unsigned char Tx_Buffer[bytes_to_read];
    volatile uint32_t *memptr = (uint32_t *)(FLASH_BASE);

    memset( Tx_Buffer, 0, bytes_to_read );
    while(dataindex<bytes_to_read)
    {
        flashmem_data.data_word = *memptr++;
        Tx_Buffer[i++] = flashmem_data.data_bytes[0];
        Tx_Buffer[i++] = flashmem_data.data_bytes[1];
        Tx_Buffer[i++] = flashmem_data.data_bytes[2];
        Tx_Buffer[i++] = flashmem_data.data_bytes[3];
        dataindex +=4;
    }

    print_m_buf(Tx_Buffer, bytes_to_read);

    dataindex=0;
    while ( dataindex <bytes_to_read)
    {
        while( !( USART1->SR & USART_SR_TXE) ) {};  //wait till transmit buffer is empty
        USART1->DR = Tx_Buffer[dataindex];
        dataindex +=1;
    }
        return true;
}