Place constant at end of used flash - not specific address

[LCE]

Heyho,

how can I put a constant at the end of the STM32's used flash? (using: STM32CubeIDE)

Not at a specific address (that's not a problem), but I'd like to have a constant always at the end of the used internal flash, independent of any other source code changes.

I just find that there's some ASCII characters = "ASCII" (twice) and lots of 0x00 at the end of my H7 and F7 bin files - that from my sources or placed by CubeIDE?

Thanks!

[mfgkw]

An alignment of 4 would be sufficient :)

[Radosław]

*.map file will show you what was places after your section. 

I'm wondering why you do this?  

[LCE]

> I'm wondering why you do this?  

Part of file check for bootloader / application update

[Radosław]

That i'm gessing, but still, not exacly understand why this method,

I'm juster after creating my bootleader for many decives  (end of flash was that last thing to bothering),   

[LCE]

Paranoia! :D

[LCE]

Shoot, now the STM32CubeProg complains about the *.elf file :

Warning: File corrupted. Two or more segments defines the same memory zone

---

And it doesn't load the complete flash content into the programmer.

:(

And this is very bad for first time flashing in production.

[mfgkw]

Showing your ld file could help helping ...

I tried a small project with this change in the ld file:

...

/* 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

ENDOFFLASH :
{
. = ALIGN(8);
} >FLASH

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

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

In the c file I added a variable like this:

const int __attribute__((section("ENDOFFLASH"))) lastVariable = 123;

[Radosław]

ENDOFFLASH :
{

. = ALIGN(8);

*(ENDOFFLASH)

} >FLASH

Input section and output, don't mix this. Also used attribute for variable or keep for section should me used

[LCE]

Now I moved the EOF section within the linker file right after the data init section where ">FLASH" is last used.

Then STM32CubeProg does not complain about the *.elf file, but the data window only shows the first flash section...

No problems with the bin file.

Here's part of my linker file - lots of sections... but it works! Except for the new EOF part with elf.

...

/* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
/* Specify the memory areas */
MEMORY
{
	ITCMRAM	(xrw)		: ORIGIN = 0x00000000, LENGTH = 64K		/* instruction RAM */

	FLBTVEC		(rx)	: ORIGIN = 0x08000000, LENGTH = 1K		/* bootloader vector table */
	FLBTFWINFO	(rx)	: ORIGIN = 0x08000400, LENGTH = 1K		/* bootloader firmware info */
	FLBOOT 		(rx)	: ORIGIN = 0x08000800, LENGTH = 250K	/* bootloader */

	FLUSER 	 	(rx)	: ORIGIN = 0x0803F000, LENGTH = 4K		/* TBD / shared One-Time-Programmable ROM */

	FLASHVEC 	(rx)	: ORIGIN = 0x08040000, LENGTH = 1K		/* application vector table */
	FLFWINFO 	(rx)	: ORIGIN = 0x08040400, LENGTH = 1K		/* application firmware info */
	FLASH  	 	(rx)	: ORIGIN = 0x08040800, LENGTH = 766K	/* application */

/* DTCM: 128 kB
 *	0x2000 0000 - 0x2001FFFF
 *	used as "general" RAM
 *	no DMA1/2 access, only MDMA memory to memory
 */
/*	DTCM_HPST(xrw)		: ORIGIN = 0x20000000, LENGTH = 15K		*/	/* DTCM heap & stack */
/*	DTCM_NOINIT(xrw)	: ORIGIN = 0x20003C00, LENGTH = 1K		*/	/* DTCM no init */
/*	DTCM_RAM(xrw)		: ORIGIN = 0x20004000, LENGTH = 112K	*/	/* DTCM */
	DTCM_RAM(xrw)		: ORIGIN = 0x20000000, LENGTH = 112K		/* DTCM */
	DTCM_NOINIT(xrw)	: ORIGIN = 0x2001C000, LENGTH = 1K			/* DTCM no init */
	DTCM_HPST(xrw)		: ORIGIN = 0x2001C400, LENGTH = 15K			/* DTCM heap & stack */

/*
without OCTOSPI / HyperRAM, all A2IP buffers in internal SRAM - NUCLEO debug only:
	SRAXI_D1(xrw)		: ORIGIN = 0x24000000, LENGTH = 96K
	SRAXI_D1_LWIP(xrw)	: ORIGIN = 0x24018000, LENGTH = 128K
	SRAXI_D1_A2IP(xrw)	: ORIGIN = 0x24038000, LENGTH = 96K
*/
/*
with OCTOSPI / HyperRAM, all A2IP buffers in external HyperRAM:
*/

/* internal */
	SRAXI_D1(xrw)		: ORIGIN = 0x24000000, LENGTH = 320K

	SRAM1_D2(xrw)		: ORIGIN = 0x30000000, LENGTH = 16K
	SRAM2_D2(xrw)		: ORIGIN = 0x30004000, LENGTH = 16K

	SRAM4_D3(xrw)		: ORIGIN = 0x38000000, LENGTH = 16K			/* only D3 access */

/* external via OCTOSPI / HyperRAM */
	OSPI_A2IP_D1(xrw)	: ORIGIN = 0x90000000, LENGTH = 0x0E00000	/* OCTOSPI 1 for A2IP */
	OSPI_FILE_D1(xrw)	: ORIGIN = 0x90E00000, LENGTH = 0x0200000	/* OCTOSPI 1 for file upload buffer */

/* external quad SPI flash via OCTOSPI */
	OSPI_FLASH(xrw)		: ORIGIN = 0x70000000, LENGTH = 0x0800000	/* OCTOSPI 2 for QSPI flash */
}


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

	/* The program code and other data goes into FLASH */
	.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)

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

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

	/* Constant data goes into FLASH */
	.rodata :
	{
		. = ALIGN(4);
		*(.rodata)  		/* .rodata sections (constants, strings, etc.) */
		*(.rodata*) 		/* .rodata* sections (constants, strings, etc.) */
		. = ALIGN(4);
	} >FLASH

	.ARM.extab : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
	.ARM :
	{
		__exidx_start = .;
		*(.ARM.exidx*)
		__exidx_end = .;
	} >FLASH

	.preinit_array :
	{
		PROVIDE_HIDDEN (__preinit_array_start = .);
		KEEP (*(.preinit_array*))
		PROVIDE_HIDDEN (__preinit_array_end = .);
	} >FLASH

	.init_array :
	{
		PROVIDE_HIDDEN (__init_array_start = .);
		KEEP (*(SORT(.init_array.*)))
		KEEP (*(.init_array*))
		PROVIDE_HIDDEN (__init_array_end = .);
	} >FLASH

	.fini_array :
	{
		PROVIDE_HIDDEN (__fini_array_start = .);
		KEEP (*(SORT(.fini_array.*)))
		KEEP (*(.fini_array*))
		PROVIDE_HIDDEN (__fini_array_end = .);
	} >FLASH


/* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
/* FLASH sections for BOOTLOADER
 *	firmware version info
 */

	.FlashBootFwSection :
	{
		KEEP(*(.FlashBootFwSection)) ;
	} >FLBTFWINFO


/* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
/* FLASH sections for APPLICATION
 *	user eeprom
 *	firmware version info
 */

	.FlashAppUserSection :
	{
		KEEP(*(.FlashAppUserSection)) ;
	} >FLUSER

	.FlashAppFwSection :
	{
		KEEP(*(.FlashAppFwSection)) ;
	} >FLFWINFO


/* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
/* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
/* internal SRAM */

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

	/* Initialized data sections goes into RAM, load LMA copy after code */
	.data :
	{
		. = ALIGN(4);
		_sdata = .;        /* create a global symbol at data start */
		*(.data)           /* .data sections */
		*(.data*)          /* .data* sections */
		*(.RamFunc)        /* .RamFunc sections */
		*(.RamFunc*)       /* .RamFunc* sections */

		. = ALIGN(4);
		_edata = .;        /* define a global symbol at data end */
	} >SRAXI_D1 AT >FLASH
/* SRAXI_D1 or DTCM_RAM */

/* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
/* EOF string file info */
	.FlashAppEOF :
	{
		. = ALIGN(8);
		*(.FlashAppEOF)
		*(.FlashAppEOF*)
		. = ALIGN(8);
	} >FLASH
/* -------------------------------------------------------- */

	/* Uninitialized data section */

...

[Radosław]

Maybe it is removed by linker as not used?

 One linker for APP and bootloader? Very bad idea !!!!!!!!!!!!