STM32U575 RAM data retention in Standby mode

[Ifer]

Hi,

I am trying to make a program in which in the micro stm32u5 is stored in ram memory some data after activating the Sleep Mode. For this I have defined in the flash file the SRAM2 memory which is the one that is supposed to be in charge of this:

MEMORY

{

RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 768K

SRAM4 (xrw) : ORIGIN = 0x28000000, LENGTH = 16K

SRAM2 (xrw) : ORIGIN = 0x20030000, LENGTH = 64K

FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 2048K

}

.ram2 (NOLOAD):

{

_sram2 = .;

*(.ram2*)

. = ALIGN(4);

_eram2 = .;

} >SRAM2

Once SRAM2 is defined, what I want to do is to save a structure that I have defined as follows:

NODEconf_TypeDef NODE_conf __attribute__((section(".ram2")));

When I run the code I can see in Memory that this structure is well stored in memory, but when I run the Standby Mode and it is awakened by the RTC alarm, all the parameters of the structure are erased.

void SLEEP_mode(void)
{
	HAL_PWREx_EnableSRAM2ContentStandbyRetention(PWR_SRAM2_PAGE1_STANDBY);

	HAL_PWR_EnableWakeUpPin(PWR_WAKEUP_PIN7_HIGH_3);
	HAL_PWR_EnterSTANDBYMode();
}

 Does anyone know if I have forgotten to configure something to keep the variable as it was?

Thanks!

[Sarra.S]

Hello @Ifer, welcome to ST Community,

Could you check if PWR_CR1.RRSB1 bit is set?