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Visitor II
May 8, 2025
Solved

stm32f429ı_dısco not written sdram

  • May 8, 2025
  • 1 reply
  • 615 views

hello i have stm32f429i-disco card. fmc settings are configured. i defined sdram in the linker file but variable sdram is not written. can you help me? i am using cubeide. my linker file is attached and i am attaching the photo of my fmc settings. my variable definition is as follows __attribute__((section(".sdram"))) uint8_t frame_buffer[320 * 240 * 2];

/*
******************************************************************************
**
** @file : LinkerScript.ld (debug in RAM dedicated)
**
** @author : Auto-generated by STM32CubeIDE
**
** Abstract : Linker script for STM32F429I-DISC1 Board embedding STM32F429ZITx Device from stm32f4 series
** 2048KBytes FLASH
** 64KBytes CCMRAM
** 192KBytes RAM
**
** Set heap size, stack size and stack location according
** to application requirements.
**
** Set memory bank area and size if external memory is used
**
** Target : STMicroelectronics STM32
**
** Distribution: The file is distributed as is, without any warranty
** of any kind.
**
******************************************************************************
** @attention
**
** Copyright (c) 2025 STMicroelectronics.
** All rights reserved.
**
** This software is licensed under terms that can be found in the LICENSE file
** in the root directory of this software component.
** If no LICENSE file comes with this software, it is provided AS-IS.
**
******************************************************************************
*/

/* Entry Point */
ENTRY(Reset_Handler)

/* Highest address of the user mode stack */
_estack = ORIGIN(RAM) + LENGTH(RAM); /* end of "RAM" Ram type memory */

_Min_Heap_Size = 0x200; /* required amount of heap */
_Min_Stack_Size = 0x400; /* required amount of stack */

/* Memories definition */
MEMORY
{
 CCMRAM (xrw) : ORIGIN = 0x10000000, LENGTH = 64K
 RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 192K
 FLASH (rx) : ORIGIN = 0x8000000, LENGTH = 2048K
 SDRAM (rw) : ORIGIN = 0xD0000000, LENGTH = 8M 
}

/* Sections */
SECTIONS
{
 .sdram (NOLOAD) :
 {
 *(.sdram)
 *(.sdram.*)
 } >SDRAM
 /* The startup code into "RAM" Ram type memory */
 .isr_vector :
 {
 . = ALIGN(4);
 KEEP(*(.isr_vector)) /* Startup code */
 . = ALIGN(4);
 } >RAM

 /* The program code and other data into "RAM" Ram type memory */
 .text :
 {
 . = ALIGN(4);
 *(.text) /* .text sections (code) */
 *(.text*) /* .text* sections (code) */
 *(.glue_7) /* glue arm to thumb code */
 *(.glue_7t) /* glue thumb to arm code */
 *(.eh_frame)
 *(.RamFunc) /* .RamFunc sections */
 *(.RamFunc*) /* .RamFunc* sections */

 KEEP (*(.init))
 KEEP (*(.fini))

 . = ALIGN(4);
 _etext = .; /* define a global symbols at end of code */
 } >RAM

 /* Constant data into "RAM" Ram type memory */
 .rodata :
 {
 . = ALIGN(4);
 *(.rodata) /* .rodata sections (constants, strings, etc.) */
 *(.rodata*) /* .rodata* sections (constants, strings, etc.) */
 . = ALIGN(4);
 } >RAM

 .ARM.extab (READONLY) : /* The "READONLY" keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
 {
 . = ALIGN(4);
 *(.ARM.extab* .gnu.linkonce.armextab.*)
 . = ALIGN(4);
 } >RAM

 .ARM (READONLY) : /* The "READONLY" keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
 {
 . = ALIGN(4);
 __exidx_start = .;
 *(.ARM.exidx*)
 __exidx_end = .;
 . = ALIGN(4);
 } >RAM

 .preinit_array (READONLY) : /* The "READONLY" keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
 {
 . = ALIGN(4);
 PROVIDE_HIDDEN (__preinit_array_start = .);
 KEEP (*(.preinit_array*))
 PROVIDE_HIDDEN (__preinit_array_end = .);
 . = ALIGN(4);
 } >RAM

 .init_array (READONLY) : /* The "READONLY" keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
 {
 . = ALIGN(4);
 PROVIDE_HIDDEN (__init_array_start = .);
 KEEP (*(SORT(.init_array.*)))
 KEEP (*(.init_array*))
 PROVIDE_HIDDEN (__init_array_end = .);
 . = ALIGN(4);
 } >RAM

 .fini_array (READONLY) : /* The "READONLY" keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
 {
 . = ALIGN(4);
 PROVIDE_HIDDEN (__fini_array_start = .);
 KEEP (*(SORT(.fini_array.*)))
 KEEP (*(.fini_array*))
 PROVIDE_HIDDEN (__fini_array_end = .);
 . = ALIGN(4);
 } >RAM

 /* Used by the startup to initialize data */
 _sidata = LOADADDR(.data);

 /* Initialized data sections into "RAM" Ram type memory */
 .data :
 {
 . = ALIGN(4);
 _sdata = .; /* create a global symbol at data start */
 *(.data) /* .data sections */
 *(.data*) /* .data* sections */

 . = ALIGN(4);
 _edata = .; /* define a global symbol at data end */

 } >RAM

 _siccmram = LOADADDR(.ccmram);

 /* CCM-RAM section
 *
 * IMPORTANT NOTE!
 * If initialized variables will be placed in this section,
 * the startup code needs to be modified to copy the init-values.
 */
 .ccmram :
 {
 . = ALIGN(4);
 _sccmram = .; /* create a global symbol at ccmram start */
 *(.ccmram)
 *(.ccmram*)

 . = ALIGN(4);
 _eccmram = .; /* create a global symbol at ccmram end */
 } >CCMRAM AT> RAM

 /* Uninitialized data section into "RAM" Ram type memory */
 . = ALIGN(4);
 .bss :
 {
 /* This is used by the startup in order to initialize the .bss section */
 _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;
 } >RAM

 /* User_heap_stack section, used to check that there is enough "RAM" Ram type memory left */
 ._user_heap_stack :
 {
 . = ALIGN(8);
 PROVIDE ( end = . );
 PROVIDE ( _end = . );
 . = . + _Min_Heap_Size;
 . = . + _Min_Stack_Size;
 . = ALIGN(8);
 } >RAM

 /* Remove information from the compiler libraries */
 /DISCARD/ :
 {
 libc.a ( * )
 libm.a ( * )
 libgcc.a ( * )
 }

 .ARM.attributes 0 : { *(.ARM.attributes) }
 

}

 

Ekran görüntüsü 2025-05-07 223050.png

    This topic has been closed for replies.
    Best answer by mƎALLEm

    Did you try to read it back in the code? I think this is something expected while reading the SDRAM content from the watch.

    1 reply

    Technical Moderator
    May 8, 2025

    Hello,

    Before going ahead with linker configuration, were you able to write a variable using a pointer?

    For the SDRAM timings, did you refer to the SDRAM example provided in the STM32CubeF4 package?: https://github.com/STMicroelectronics/STM32CubeF4/tree/master/Projects/STM32F429I-Discovery/Examples/FMC/FMC_SDRAM

     

     

    edramdenAuthor
    Visitor II
    May 8, 2025

    I found what I was missing from the file you linked and added it and I can write data to sdram. But the data I write is in a mixed order. I am putting the code I wrote below as a picture and the value I read from memory in debug.

     uint16_t *sdram_address = (uint16_t *)0xD0000000;
    
     for (uint32_t i = 0; i < 1024; i += 2)
     {
     sdram_address[i] = 0x1234; 
     sdram_address[i + 1] = 0x5678; 
     }

     

    edramden_0-1746730022030.png

     

     

    edramdenAuthor
    Visitor II
    May 8, 2025
     uint32_t *sdram_address = (uint32_t *)SDRAM_BANK_ADDR;
    
     for (uint32_t i = 0; i < 1024; i++)
     {
     sdram_address[i] = 0x12345678;
     }

    edramden_1-1746730210338.png