STM32F746 Disco clear memory section

[MFawzy]

I Have STM32F746 Disco and i have a memory section that sould be initialized to zero.

and the aim behind this is to keep the memory content whenever the board is rest.

but unfortanlty, this section is being clear every time i restart the debuger.

the section is holding structure which is defined as the following:

PROBE_strExceptionInfoType objstrExceptionInfo __attribute__ ((section (".ramException")));

i tried the same criteria with STM32F3 and STM32F4 and it worked but it didn't work with STM32F7

the linker is attached.

Any idea?

Best Regards,

[Tesla DeLorean]

You want it zero'd or you want it left uninitialized so it survives reset. Your question is poorly stated.

Code in startup.s is responsible for memory initialization and clearing.

If using the linker script make sections NOLOAD

Or use pointers, and don't tell the linker about the memory you don't want it touching.

 .ramException (NOLOAD) :
 {
 . = ALIGN(4);
 } > CRASH_DUMP_PART

[MFawzy]

Thank you, this fixed the issue of the clearing for the memory. but i'm getting strange phenomna that is shown with STM32H7 and SM32F7 that the memory isn't cleared when i rest the debuger but the existance data is being distorted. Any Idea?

[Tesla DeLorean]

The MCU doesn't clear the memory,​ it will have undefined content in the memory cells when it first starts and may retain content whilst still powered, directly or parasitically.

[Piranha]

For this purpose just move that structure to the beginning of DTCM. But generally one cannot develop code for Cortex-M7 without understanding cache maintenance and memory barriers.