const struct array in FLASH instead of RAM

Martin Kunz

Other Parts Discussed in Thread: MSP430F4250, CODECOMPOSER

Hello,

I am using Code Composer Version: 4.2.3.00004, a MSP-FETU430IF and a MSP430F4250

I got a struct defined:

struct s_Test
{
volatile unsigned char* MemoryCell;
int16_t* PointerToValue;
int16_t Minimum;
int16_t Maximum;
char* MenueText;
};

then I want to have a Table of more entries of this struct globally available:

const struct s_ Test const Data[_e_DataLength] =
{
{NULL, &(DataMemory.Value), -1999, 9999, MenueTexte[0]},
...
}

now the whole thing is put into RAM not into FLASH, so using const or not makes no difference at all.

when i explicitly put #pragma DATA_SECTION(".const") before the definition, the RAM seems to be free, but the whole table is not initialized with the data.

How can i create a table in flash that is initialized with data?

Thank you,

Martin

over 14 years ago

0 Joern over 14 years ago

Genius 3055 points

Probably you did, but to be sure, am I assuming right that you actually wrote something like:

#pragma DATA_SECTION(Data, ".const")

Additionally, as far as I understand this mechanism, somewhere it has to be declared which memory type shall be used for the different data sections.Did you?

Concerning "flash" (until shortly before now I didn't think that this memory might be bound to a data section, so thanks for your hint to that) maybe this thread post will be helpful for you...

Regards,
Joern.

0 Martin Kunz over 14 years ago in reply to Joern

Prodigy 20 points

Hello,

I used the parameter for deleting the complete flash before programming.
I used the default cmd-File of CodeComposer for my chip, this says for the memory mapping:

/****************************************************************************/
/* SPECIFY THE SYSTEM MEMORY MAP */
/****************************************************************************/

MEMORY
{
SFR : origin = 0x0000, length = 0x0010
...
FLASH : origin = 0xC000, length = 0x3FE0
...

****************************************************************************/
/* SPECIFY THE SECTIONS ALLOCATION INTO MEMORY */
/****************************************************************************/

SECTIONS
{
.bss : {} > RAM /* GLOBAL & STATIC VARS */
.sysmem : {} > RAM /* DYNAMIC MEMORY ALLOCATION AREA */
.stack : {} > RAM (HIGH) /* SOFTWARE SYSTEM STACK */
...
.const : {} > FLASH /* CONSTANT DATA */
...

Another thing is, when I declare:

char* const MenueTexte[100]
{
...
}

this is put into flash as I expected.

But this is always put into ram:

struct s_Data[100]
{
...
}

Thank you

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const struct array in FLASH instead of RAM