topic Execution code in ram in S32K

Execution code in ram

markulhu — Sat, 25 Jan 2020 17:32:45 GMT

hi, for my eeprom driver designing, i copyed the code from flash to ram,but jump to code in ram, it cause "HardFault" exception. is there any configuration that must be set manually?

//static Std_ReturnType Eep_EnEepRam(void)

{

FTFC_FCCOB0 = 0x81; /* SETRAM */
FTFC_FCCOB1 = 0x00; /* FlexRAM available for emulated EEPROM */
FTFC_FSTAT |= 0x80; /* Launch command */
while (FTFC_FSTAT & 0x80) {}
return FTFC_FSTAT == 0? E_OK: E_NOT_OK;

}

//void Eep_Init(void)

{

const uint8* EnEepFun;
uint8* LoadRam = (void*)0x1FFFF000;
uint32 Depart;

Depart = (SIM_FCFG1 & 0xF000) >> 12;

if (Depart == 3 || Depart == 4 || Depart == 8 || Depart == 10 || Depart == 11)
{
EepRamEnabled = TRUE;
return;
}

EnEepFun = (const void*)Eep_EnEepRam;

(void)memcpy(LoadRam, EnEepFun, 20);
if (((Std_ReturnType(*)(void))LoadRam)() == STD_OK)
{
EepRamEnabled = TRUE;
return;
}

}

Re: Execution code in ram

dianabatrlova — Mon, 27 Jan 2020 14:56:26 GMT

Hello Steven,

You can use code below to place the function into the RAM and after that just use the name of the function to call.

__attribute__ ((section(".code_ram"))) // place the code below into .code_ram section
void YourFunction(void);

Or you can check the S32_SBC[CFSR] register. For more details, please, look at the Cortex-M4 Devices Generic User Guide, chapter 4.3.10: http://infocenter.arm.com/help/topic/com.arm.doc.dui0553b/DUI0553.pdf

I assume that you use S32K14x.

I hope it helps.

Best regards,

Diana

Re: Execution code in ram

markulhu — Thu, 30 Jan 2020 05:49:48 GMT

Diana,thanks for your advice! i have located the reason ,that because the lowest bit of PC of thumb code must be 1. so i changed LoadRam's value from 0x1FFFF000 to 0x1FFFF001, it seems running ok.

thank you for your help again!