Put a bootloader program at the bottom of the FLASH memory

Question

I try to creat a custom bootloader for STM32L1 serie card and I need to put my bootloader code at the bottom of my flash memory. Then i can flash my memory properly. I know it can be specified in the linker scrip but i don't know how to do that. I declared my bootloader section like this :

  .bootsection :
  {
    . = ALIGN(4);
    KEEP(*(.bootsection)) /* Bootloader code */
    . = ALIGN(4);
  } >FLASH

and my memory is set like this :

MEMORY
{
  FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 512K
  RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 80K
  MEMORY_B1 (rx)  : ORIGIN = 0x60000000, LENGTH = 0K
}

anyone have an idea on the command ?

That's not proper linker script syntax... I think doing that will give you a syntax error. — John M, Jun 11 '15 at 12:04
Also, I feel like your question is a little unclear. Can you please explain why your current linker script is not working? Also, what's up with the `MEMORY_B1`? Why is it's length 0? — John M, Jun 11 '15 at 12:05
this linker script is working , i did not gave you all the script code . I don't know what is this MEMORY_B1, i think i can delete it. — kidz55, Jun 11 '15 at 12:11
Thanks for posting your bootloader code. Unfortunately, I don't really understand your problem. What is wrong with the current linker script? What does it do that is not right? — John M, Jun 11 '15 at 12:32
i just modified it , i think it will work but i did not tried it yet — kidz55, Jun 11 '15 at 12:37

score 2 · Accepted Answer · answered Jun 11 '15 at 12:20

Here is my linker script, i tried something with a new memory section

 MEMORY
    {
      FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 510K
      MEM_BOOT (rx)   : ORIGIN = 0x0807CFFE, LENGTH = 2K
      RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 80K
      MEMORY_B1 (rx)  : ORIGIN = 0x60000000, LENGTH = 0K
    }

    /* Define output sections */
    SECTIONS
    {
      /* The startup code goes first into FLASH */
      .isr_vector :
      {
        . = ALIGN(4);
        KEEP(*(.isr_vector)) /* Startup code */
        . = ALIGN(4);
      } >FLASH


      .bootsection :
      {
        . = ALIGN(4);
        KEEP(*(.bootsection)) /* Bootloader code */
        . = ALIGN(4);
      } >MEM_BOOT

here's my boot code , i wroted the flash program but the erase program is not written yet.

#define MY_BL_FUNCTIONS __attribute__((section(".bootsection")))

void BootLoader(void) MY_BL_FUNCTIONS;
uint8_t Flash_Write ( uint32_t StartAddress, uint8_t *p, uint32_t Size ) MY_BL_FUNCTIONS;

void BootLoader(void) {
    char buffer[1000];
    int i = 0;
    /*test if we enter the bootloader , toggle the led and send a string to the usart */
    GPIO_ToggleBits(GPIOA, GPIO_Pin_5);
    do {
        buffer[i] = Uart2ReadChar();
        i++;
    } while (buffer[i] != '\0');

    SendString(buffer,USART2);
}

uint8_t Flash_Write ( uint32_t StartAddress, uint8_t *p, uint32_t Size )
{
      uint32_t idx;
      uint32_t Address;
      __IO FLASH_Status status = FLASH_COMPLETE;

      Address = StartAddress;

      /* Unlock the FLASH Program memory */
      FLASH_Unlock ( );

      /* Clear all pending flags */
      FLASH_ClearFlag ( FLASH_FLAG_EOP     |
                        FLASH_FLAG_WRPERR  |
                        FLASH_FLAG_PGAERR  |
                        FLASH_FLAG_SIZERR  |
                        FLASH_FLAG_OPTVERR );

      while  ( Address < StartAddress + Size )
      {
            status = FLASH_FastProgramWord ( Address,  *(uint32_t *)p );
            Address = Address + 4;
            p = p + 4;
            if ( status != FLASH_COMPLETE ) return status;
      }

      /* Lock the FLASH Program memory */
      FLASH_Lock ( );

      return (uint8_t)status;
}

There seems to be a bug in your Flash_Write() code. If the function FLASH_FastProgramWord() return a different value of FLASH_COMPLETE, your function exits and leave flash memory unlocked. — ViniCoder, Aug 05 '16 at 19:29

Put a bootloader program at the bottom of the FLASH memory

1 Answers1