s32k344 loss RAM data after functional reset

[liwenchao]

Hello , I am trying to retention RAM data in s32k344 after functional reset , and my MCAL version is : SW32K3_RTD_4.4_R21-11_3.0.0_P01_HF02. 

when flash bootloader complete application update , My code call function "Mcu_PerformReset()" , and I want to retention some information in RAM . but  However, the data in this RAM is lost after reset.

I read MC_RGM registers by debug as flow

Did I miss any preconditions before functional reset ???

[YanyiQiu]

hello liwenchao,

do you have solved this problem?

the data in this RAM is lost after reset. (question mark in this ram use emulator)

thanks a lot

[Robin_Shen]

Hi

I'm sorry for the delay.

Functional resets will keep SRAM data unchanged by hardware mechanism.
Destructive resets cannot guarrantee the SRAM data integrity.

For the S32DS default startup code, the SRAM ECC initialization will be performed no matter what reset source it is. So the SRAM data is overwritten after each reset.

You need modify the startup code to check the reset source and perform SRAM ECC initialization only for some reset sources.

Best Regards,
Robin
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[liwenchao]

Thanks for your reply .

I My startup code , I read FES / DES to validate if program is start from power on. and only power on , the SRAM initialization will be performed.

So , Are there any missing configurations when using functional reset? 

[Robin_Shen]

Please refer to the issue mentioned in the S32K344 reset reason, which resulted in the reset reason being incorrectly read as power on reset.

[liwenchao]

I check reset reason in boot manager , When I call Functional reset in MCAL by application , It works Ok , and My SRAM can keep success . but When I call the save Function reset in MCAL by FBL , the SRAM losted