Unable to save modified .ld file when CubeMX generates the CMake project

[Nobody233]

I used CubeMX to generate CMake project for STM32H750XBH6.

Then I have to modify STM32H750XBHx_FLASH.ld because DMA1 can't access the DTCMRAM.

/* Specify the memory areas */
MEMORY
{
DTCMRAM (xrw)      : ORIGIN = 0x20000000, LENGTH = 128K
RAM_D1 (xrw)      : ORIGIN = 0x24000000, LENGTH = 512K
RAM_D2 (xrw)      : ORIGIN = 0x30000000, LENGTH = 288K
RAM_D3 (xrw)      : ORIGIN = 0x38000000, LENGTH = 64K
ITCMRAM (xrw)      : ORIGIN = 0x00000000, LENGTH = 64K
FLASH (rx)      : ORIGIN = 0x8000000, LENGTH = 128K
}

  /* Uninitialized data section */
  . = ALIGN(4);
  .bss :
  {
    /* This is used by the startup in order to initialize the .bss secion */
    _sbss = .;         /* define a global symbol at bss start */
    __bss_start__ = _sbss;
    *(.bss)
    *(.bss*)
    *(COMMON)

    . = ALIGN(4);
    _ebss = .;         /* define a global symbol at bss end */
    __bss_end__ = _ebss;
  } >DTCMRAM

 But everytime I use CubeMX regenerate the project, STM32H750XBHx_FLASH.ld will be recovered. My changes didn't save.

How can I save this modified STM32H750XBHx_FLASH.ld when CubeMX regenerates project?

[Semer CHERNI · Accepted solution]

Hello @Nobody233 

First let me thank you for posting.

In fact, this is a known behavior of STM32CubeMX and under investigation. 

As a temporary solution I propose that you make modification on a back up linker file. Then use a script to copy it and replace the one imported by STM32CubeMX at each code generation.

The script could be executed using the "User action" feature in STM32CubeMX.

BR,
Semer.

[SMarie]

Or, as a alternative you can create a new file STM32H750XBHx_FLASH_CUSTOM.ld with the modifications you want in it. And use this one as the linker script in your project configuration :

Then on your next CubeMX generations, the STM32H750XBHx_FLASH.ld will be regenerate but not the STM32H750XBHx_FLASH_CUSTOM.ld which will still be the one used by your compiler.

[Nobody233]

Hi, @Semer CHERNI 

Thanks for your reply. 

Firstly, it could be work as your suggestion.

Secondly, I found another solution.

I found that "cmake\gcc-arm-none-eabi.cmake" and "CMakeLists.txt" will not be covered when CubeMX regenerates project. Then I modified this two files to use another .ld file. The STM32H750XBHx_FLASH.ld would still exist but not be used.

1. add the new .ld file.

2. add target_link_options in "CMakeLists.txt".

# Setup linker parameters
target_link_options(${CMAKE_PROJECT_NAME} PRIVATE
    -T "${CMAKE_SOURCE_DIR}/STM32H750XBHx_RAM.ld"
    # -u _printf_float              # STDIO float formatting support (remove if not used)
)

3. remove the STM32H750XBHx_FLASH.ld in "cmake\gcc-arm-none-eabi.cmake"

set(CMAKE_C_LINK_FLAGS "${TARGET_FLAGS}")
# set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -T \"${CMAKE_SOURCE_DIR}/STM32H750XBHx_FLASH.ld\"")
set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} --specs=nano.specs")
set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -Wl,-Map=${CMAKE_PROJECT_NAME}.map -Wl,--gc-sections")
set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -Wl,--start-group -lc -lm -Wl,--end-group")
set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -Wl,--print-memory-usage")

By the way, the 4th line of step 4 could enable the printf of float value.

BR,

Nobody.

[Nobody233]

Hi, @SMarie .

Thanks for your reply. 

Sorry about the point that I didn't mentioned is I'm using VS Code.

And I found another solution for VS Code, see upper floor.

Thanks for your kindness.

BR,

nobody.