S32K中的主题 Re: does The SRAM being Set to 0 if MCU get FUNC_ RST bit Setting in MC_ME register

does The SRAM being Set to 0 if MCU get FUNC_ RST bit Setting in MC_ME register

yinqiu — Sat, 03 Aug 2024 07:48:40 GMT

hello:

I want to take use of a share(no clear )RAM,because I want to jump into bootload if application gets the uds 10 02,so ASW should put reflash flag in a noclear ram which can keep the reflash flag after reset(is the type of reset make any different performance of sram?). but when I try to call "MCU_PerformReset",and watch the value of ram which I set NOCLEAR or NOLOAD in the ld file,but I find the value is set to zero before the boot excute the function "init_data_bss" which in the "startup.c". I can not set brekpoint in the .S file, so I can ont sure the behaviour in the .S file .

回复： does The SRAM being Set to 0 if MCU get FUNC_ RST bit Setting in MC_ME register

yinqiu — Mon, 05 Aug 2024 02:08:27 GMT

I got the response form FAE and he told me that I should take use of the memory defined as "ram_rsvd2" and move the origin address of ram_rsvd2 forward. he means the value of ram_rsvd2 won't be cleared by MCU .

Re: does The SRAM being Set to 0 if MCU get FUNC_ RST bit Setting in MC_ME register

danielmartynek — Tue, 06 Aug 2024 08:52:40 GMT

Hello @yinqiu,

The SRAM content is preserved across functional reset.

The SRAM is initialized in startup_cm7.s up to __INT_SRAM_END, which is by default set to ORIGIN(ram_rsvd2), so you need to adjust that.

After any reset, when the debugger is disconnected, we can trap the execution is a loop like this.

Regards,

Daniel