S32K3X8 singlecore TCM backdoor access

[dmitry_buchynski]

Hello, NXP team and others.

I'm working with s32k358 with decoupled cores as we aim for s32k328 later.

I have problems using DTCM2 and ITCM2 through backdoor when running only core 0.

So I have set up the project to use single core 0 and I can read and write DTCM0/ITCM0 and DTCM1/ITCM1 via backdoor access. But when I try to write values to DTCM2/ITCM2 via backdoor they are always 0.
I used this project Example_S32K314_DTCM1_Backdoor_RTD201_DS34_v3 - NXP Community as a reference and also chapter '3.4 TCM as system memory' of S32K3xx Reference Manual, Rev. 9, 07/2024.

Below is the example project attached where one can observe the issue. 

The files modified are:
1) src/main.c
2) Project_Settings\Linker_Files\linker_flash_s32k328.ld
3) Project_Settings\Startup_Code\startup_cm7.s
4) Project_Settings\Startup_Code\Vector_Table.s - only __Stack_dtcm_start renamed to __Stack_start

[dmitry_buchynski]

@davidtosenovjan Hello, thanks for response. Yes I have done DCF programming. But then my questions are:
1) what does disabled core on s32k328 mean? It cannot be used in any way?
2) what is the correct way to access all the TCM memory using core 0 on s32k328 and s32k358 (DTCM0/1/2 and ITCM0/1/2)?

[davidtosenovjan]

1) From user point of view, there is no difference whether you buy S32K328 or switch S32K358 to S32K328 configuration. 'Disabled' mean the core is not present or any of its part.

2) I would switch the device to S32K338. Then you have 3 decoupled cores available.

[dmitry_buchynski]

@davidtosenovjan unfortunately we have s32k328 already installed in the device. So I would like to know how core 0 can access ITCM2 and DTCM2 through the backdoor.

[davidtosenovjan]

S32K358 has only two cores: 1 pair in lockstep and 1 decoupled.

Have you perfomed DCF record programming in order to switch it to the S32K338 configuration?

S32K328 is dual core configuration as well.