relocating code from FLASH to RAM

[sandeepsirpatil]

Hello,

Code warrior version: 10.3

Processor: MPC5605B

I am trying to relocate a function from flash to RAM and having trouble with the linker. I have made necessary changes as per the App note AN4497. The linker is not obeying the relocation directive and placing the code at memory address of 0x000000.  I have attached the project.

Following the guideline in the appnote (AN4497) i have been successful in relocating a block of data (const data) form flash to RAM. When I try for a function I am having this trouble.

I have tried as suggested in this post (How to Copy Function from Flash to RAM & execute it) and it did not work.

Any help is appreciated.

Thanks,

Sandeep Sirpatil

in  main.c i have the following :

#pragma section ".myCodeInRAM" data_mode=far_abs

__declspec(section ".myCodeInRAM") void serviceWatchdog(void);

void serviceWatchdog(void)

{

  SWT.SR.R = 0x0000A602; /* Service Watchdog: write 0xA602 followed by 0xB480 */

  SWT.SR.R = 0x0000B480;

}

in LCF file i have:

	internal_ram:	org = 0x40000000,   len = 0x0000D000 /* 56K */
	myram:	org = 0x4000D000,   len = 0x00001000 /* 4K */
	heap  :	org = 0x4000E000,   len = 0x00001000 /* 4K */

	.my_ram :
	{
	*(myCodeInRAM)
	} > myram

In the MAP file:

.my_ram section layout

  Starting        Virtual  File

  address  Size   address  offset

  ---------------------------------

.myCodeInRAM section layout

  Starting        Virtual  File

  address  Size   address  offset

  ---------------------------------

  00000000 000022 00000000 00001000  1 .myCodeInRAM     main_c.obj

  00000000 000022 00000000 00001000  2 serviceWatchdog     main_c.obj

Memory map:

.myCodeInRAM 00000000 00000024 00001000 00003800 00003800

0

Original Attachment has been moved to: testCodeinRam.zip

[Carlos_Musich · Accepted solution]

Hello Sandeep,

You can see below a very simple example:

In main.c

#pragma section ".myCodeInRAM" code_mode=far_abs    //For routines code_mode need to be mentioned

__declspec(section ".myCodeInRAM") int _add(int a , int b);

int main(void) {

   volatile int i = 0; 

   volatile int total = 0;

   for (;;)

   {

      total = _add(i , i);

      i++;

  }

}

__declspec (section ".myCodeInRAM") int _add(int a , int b)

{

  returna + b;

}

In .LCF

GROUP : {

   .my_ram (VLECODE): {    //instruction mode VLECODE has to mentioned

        *(.myCodeInRAM)

   }

} > myram

Hope it helps.

Carlos

[sandeepsirpatil]

This seems to be the trick. The linker places the function at the correct address (Flash and RAM). I also tested it in my main project code and it seems to work correctly.

Thank you very much.

[trytohelp]

Hi,

Can I recommend you to contact the support team via CRM system ?

This issue will be probably moved to another team.

For Technical Support Issues please use Freescale on line support web page.

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Else you can send an email to support@freescale.com

Regards

Pascal