Setting address of variable in flash

[Sergy]

Hi,

Is it possible to set an address lets say for an array to be in Flash memory on compilation? So that way I dont need to reserve memory twice - once in my program memory area and once in flash.

Thanks!

[Nikita]

You mean something like this?

const uint8_t __attribute__((section (".my_array_in_flash_sect"))) my_array[my_array_size] __attribute__((used)) = {0};

gcc_nrf51_s110_xxaa.ld

/* Linker script to configure memory regions. */
SEARCH_DIR(.)
GROUP(-lgcc -lc -lnosys)

MEMORY
{
  FLASH (rx) : ORIGIN = 0x14000, LENGTH = 0x13C00 /* 80 kB is taken by S110, 16kB is taken by bootloader,  160 kB available for application in single bank mode or 80 kB in dual bank mode, 1kB for my array */
  my_array_in_flash (rwx) : ORIGIN = 0x27C00, LENGTH = 0x400 /* my array */
  RAM (rwx) : ORIGIN = 0x20002000, LENGTH = 0x2000 /* 8 kB, 8 kB is taken by S110. */
}
INCLUDE "gcc_nrf51_common.ld"

gcc_nrf51_common.ld

SECTIONS
{
    .my_array_in_flash_block 0x00027C00 :
    {
        KEEP(*(.my_array_in_flash_sect))
    } > my_array_in_flash
...

UPD:

For Keil it's like this:

#define MY_ARRAY_ADDRESS     0x28C00
const uint8_t  my_array[my_array_size] __attribute__((at(MY_ARRAY_ADDRESS))) __attribute__((used)) = {0};

[Sergy]

something like this indeed! how can i set it up in Keil?

[Sergy]

fantastic thanks a lot! but i cant define a second one? so basically i need to make just one array and then just work with it?

[Nikita]

Yes, you just need to create my_array somewhere in your program with that line and then you can use it as any other array.

And one more, I edited my answer and added const declaration as it may cause some troubles like this.

[Sergy]

Awesome! Thanks so much!