Linker / Scatter

[jakob.brunhart]

Hello everybody

Controller: STM32H743ZI

I have a const uint8_t array which I want to place in the flash at a specific location. The location is Address: 0x08180000. For that reason I created a *.sct file. The used tag is "MXG5XX".

LOAD_FLASH_BANK 0x08000000 0x00200000
{ 
                                            
  EXEC_FLASH_BANK_1 0x08000000 0x00100000
  {    
    *.o (RESET, +First)
    *(InRoot$$Sections)
    .ANY (+RO)
    .ANY (+XO)
  }
  
  EXEC_FLASH_BANK_2 0x08180000 0x00080000
  {        
    *(.MXG5XX)
  }    
  
  EXEC_DTCM 0x20000000 0x00020000                               
  {
   .ANY (+RW)
   .ANY (+ZI)
  }
                                                                
  EXEC_AXI 0x24010000 0x00070000                                
  {
    .ANY (+RW)
    .ANY (+ZI)
  }  
 
  EXEC_ITCM 0x00000000 0x10000
  {
    .ANY (itcm)
  }  
  
}

The const array is called mxg5xx_firmware_binary and is defined as follows:

__attribute__((section (".MXG5XX"))) 
const uint8_t mxg5xx_firmware_binary [] = {
	0xB0, 0x14, 0x00, 0x20, 0xDD, 0x11, 0x00, 0x00, 0xE5, 0x11, 0x00, 0x00, 0xE7, 0x11, 0x00, 0x00
};

After the build process the *.map shows the following for the array:

Image Symbol Table
...
mxg5xx_firmware_binary                   0x08180000   Data          16  main.o(.MXG5XX)
...

So far everything seems to be correct.

If I start debugging now the address for the const array is correct (0x08180000) but the memory at this address shows only 0xFF and not the values defined for the array.

I have a minimum project for NUCLEO-H743ZI.

Any Idea? Thank you.

Regards

Jakob

[Tesla DeLorean]

Split into two load regions, with the second describing the last 512KB, and put the second execution region inside that.

[jakob.brunhart]

Hi Clive

Thank you for your response.

Do you mean like this:

LOAD_FLASH_BANK_1 0x08000000 0x00100000
{                                          
  EXEC_FLASH_BANK 0x08000000 0x00100000
  {    
    *.o (RESET, +First)
    *(InRoot$$Sections)
    .ANY (+RO)
    .ANY (+XO)
  }
 
  EXEC_DTCM 0x20000000 0x00020000                               
  {
   .ANY (+RW)
   .ANY (+ZI)
  }
                                                                
  EXEC_AXI 0x24010000 0x00070000                                
  {
    .ANY (+RW)
    .ANY (+ZI)
  }  
 
  EXEC_ITCM 0x00000000 0x10000
  {
    .ANY (itcm)
  }
}
 
LOAD_FLASH_BANK_2 0x08100000 0x00100000
{ 
  ;EXEC_FLASH_BANK_2_1 0x08100000 0x00080000
  ;{
    
  ;}
  
  EXEC_FLASH_BANK_2_2 0x08180000 0x00080000
  {        
    *(.MXG5XX)
  } 
}

It behaves the same.

Regards

Jakob

[jakob.brunhart]

Hi Clive

Please se my answer below.

Thank you.

[Tesla DeLorean · Accepted solution]

The base addresses need to be consistent, you can't have the data floating in the middle of the load region, the scatter loader wants to unpack it.​

[jakob.brunhart]

... Thank you. This version works.

LOAD_FLASH_BANK_1 0x08000000 0x00100000
{                                          
  EXEC_FLASH_BANK_1 0x08000000 0x00100000
  {    
    *.o (RESET, +First)
    *(InRoot$$Sections)
    .ANY (+RO)
    .ANY (+XO)
  }
 
  EXEC_DTCM 0x20000000 0x00020000                               
  {
   .ANY (+RW)
   .ANY (+ZI)
  }
                                                                
  EXEC_AXI 0x24010000 0x00070000                                
  {
    .ANY (+RW)
    .ANY (+ZI)
  }  
 
  EXEC_ITCM 0x00000000 0x10000
  {
    .ANY (itcm)
  }
}
 
LOAD_FLASH_BANK_2 0x08180000 0x00080000
{ 
  EXEC_FLASH_BANK_2 0x08180000 0x00008000
  {
    *(.MXG5XX)  
  }
}

.