ALL

my Cortex M3 happen Hardfault after running some time. it is long sometimes and short sometimes. no rule. and it use FreeRTOS7.5.2, after Hardfault, I dump CPU context as following [Hard fault handler] R0 = 2e R1 = 0 R2 = ffffffff R3 = 20005f48 R12 = 4f588000 LR = fffffffd PC = 28024f14 PSR = 21000035 BFAR = e000ed38 CFSR = 100 HFSR = 40000000 DFSR = 0 AFSR = 0

it is strange that PC value is not a valid address, anyone meet same problem ?

If the dump was done while you were in the hardfault handler then I would expect the PC to point to code inside the hardfault handler.

I would suggest starting here: http://www.freertos.org/FAQHelp.html for a list of possible problems if the hardfault is occurring in FreeRTOS itself (rather than in your application).

Regards.

I always enable conf_assert and make sure that there is no assert when hardfault happen. I start to guess HW issue and collect more record about PC value, it may be 0x0Cxxxxxx, 0x28xxxxxx, 0xc8xxxxxx, it is random case

How are you working out the PC value?

Regards.

use following code to save cpu context when hardfault happen IMPORT hardfaulthandlerc
TST LR, #4
ITE EQ
MRSEQ R0, MSP
MRSNE R0, PSP
B hardfaulthandlerc then, go to hardfault_handle to dump those context

void hardfaulthandlerc(unsigned int * hardfaultargs)
{
unsigned int stackedr0;
unsigned int stackedr1;
unsigned int stackedr2;
unsigned int stackedr3;
unsigned int stackedr12;
unsigned int stackedlr;
unsigned int stackedpc;
unsigned int stackedpsr;

while(1)
{
    stacked_r0 = ((unsigned long) hardfault_args[0]);  
    stacked_r1 = ((unsigned long) hardfault_args[1]);  
    stacked_r2 = ((unsigned long) hardfault_args[2]);  
    stacked_r3 = ((unsigned long) hardfault_args[3]);  
    stacked_r12 = ((unsigned long) hardfault_args[4]);  
    stacked_lr = ((unsigned long) hardfault_args[5]);  
    stacked_pc = ((unsigned long) hardfault_args[6]);  
    stacked_psr = ((unsigned long) hardfault_args[7]);  
    printf ("[Hard fault handler]\n");  
    printf ("R0 = %x\n", stacked_r0);  
    printf ("R1 = %x\n", stacked_r1);  
    printf ("R2 = %x\n", stacked_r2);  
    printf ("R3 = %x\n", stacked_r3);  
    printf ("R12 = %x\n", stacked_r12);  
    printf ("LR = %x\n", stacked_lr);  
    printf ("PC = %x\n", stacked_pc);  
    printf ("PSR = %x\n", stacked_psr);  
    printf ("BFAR = %x\n", (*((volatile unsigned long *)(0xE000ED38))));  
    printf ("CFSR = %x\n", (*((volatile unsigned long *)(0xE000ED28))));  
    printf ("HFSR = %x\n", (*((volatile unsigned long *)(0xE000ED2C))));  
    printf ("DFSR = %x\n", (*((volatile unsigned long *)(0xE000ED30))));  
    printf ("AFSR = %x\n", (*((volatile unsigned long *)(0xE000ED3C))));  
    printf ("SCB_SHCSR = %x\n", SCB->SHCSR);
    getkeychar();
}

}

Could the problem be in the printf() from an exception handler? If you look at the value of stacked_pc in the debugger does it match the value printed out?