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placing data in an absolute address in flash(ROM)

Question asked by Koorosh Hajiani on Jun 21, 2017
Latest reply on Sep 9, 2019 by Ummer Kunnummalkandy


I'm trying to place a variable called my_checksum in an absolute flash location. Target is S32K144EVB and I'm using design studio 1.3. Here is what I did:

In the linker file used for this project which is attached.I added  m_chksum to memory areas:


/* Specify the memory areas */



/* Flash */

m_interrupts (RX) : ORIGIN = 0x00000000, LENGTH = 0x00000400

m_flash_config (RX) : ORIGIN = 0x00000400, LENGTH = 0x00000010

m_text (RX) : ORIGIN = 0x00000410, LENGTH = 0x00070000/*0x0007FBF0*/

/*this was added*/

m_chksum (RX) : ORIGIN = 0x00070410, LENGTH = 0x00000008

/* SRAM_L */

m_data (RW) : ORIGIN = 0x1FFF8000, LENGTH = 0x00008000


/* SRAM_U */

m_data_2 (RW) : ORIGIN = 0x20000000, LENGTH = 0x00007000



and added the section below:


/* koor added*/

.myBufBlock :


. = ALIGN(4);

KEEP(*(.myBufBlock)) /* keep my variable even if not referenced */

. = ALIGN(4);

} > m_chksum


In the main.c I added the line below, just before main()


__attribute__((section (".myBufBlock"))) unsigned long my_chksum=0X12345678 ;


looking at the MAP file it places my_chksum at  0x1fff8400                my_chksum

which is the start of the code _ram in .data section .


Any idea why is it doing that?

The target is a 512k part and I am not exceeding that .when I build the code and run , everything seems normal except the address of my_chksum variable.



Koorosh Hajiani

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