topic Linker definition file clarification in S32K

Linker definition file clarification

biju_nair — Fri, 14 Apr 2023 05:45:30 GMT

Hi,

We are using a platform which has S32K314 controller. The datasheet of this part says that this has 512KB of total RAM. But the following is the linker definition file that i am using. What i see is, i am not able to allocate more than 185 KB of memory in my code (Both BSS and Datasegment combined). Can someone help me on how to utilize the full 512KB of memory in this system ?

The following is my linker description contents.

MEMORY
{
int_flash : ORIGIN = 0x00400000, LENGTH = 0x003D4000 /* 4096K - 176K (sBAF + HSE)*/
int_itcm : ORIGIN = 0x00000000, LENGTH = 0x00008000 /* 32K */
int_dtcm : ORIGIN = 0x20000000, LENGTH = 0x00010000 /* 64K */
int_sram : ORIGIN = 0x20400000, LENGTH = 0x0002DF00 /* 183.9K */
int_sram_fls_rsv : ORIGIN = 0x2042DF00, LENGTH = 0x00000100 /* 0.1K */
int_sram_stack_c0 : ORIGIN = 0x2042E000, LENGTH = 0x00001000 /* 4KB */
int_sram_stack_c1 : ORIGIN = 0x2042F000, LENGTH = 0x00001000 /* 4KB */
int_sram_no_cacheable : ORIGIN = 0x20430000, LENGTH = 0x0000FF00 /* 64KB, needs to include int_results */
int_sram_results : ORIGIN = 0x2043FF00, LENGTH = 0x00000100
int_sram_shareable : ORIGIN = 0x20440000, LENGTH = 0x00004000 /* 16KB */
ram_rsvd2 : ORIGIN = 0x20444000, LENGTH = 0 /* End of SRAM */
}

Regards, Biju

Re: Linker definition file clarification

danielmartynek — Fri, 14 Apr 2023 09:35:46 GMT

Hi Biju,

As you can see in the memory map (attached to the RM), there is

direct access to ITCM_0 (32KB) + DTCM_0 (64KB) + SRAM0 (160KB) + SRAM1 (160KB) = 416KB,
backdoor access to ITCM_1 (32KB) + DTCM_1 (64KB) = 96KB

You can extend or add regions in the linker file based on the addresses below.

Regards,

Daniel

Re: Linker definition file clarification

biju_nair — Tue, 06 Jun 2023 04:22:31 GMT

Hi Daniel,

As S32K314 does not have a second core, can i still access DTCM_1 via backdoor ? What i meant is, even without the second core, will i still be able to utilize the DTCM_1 memory ? If so, what linker script change do i need and how can i allocate variables into that ? For DTCM_0, i use the following attribute to access it.

__attribute__ ((section(".dtcm0_data")))

Regards, Biju