Hard Fault running cmwx1zzabz_0xx on B-L072Z-LRWAN1 discovery board

[CCP]

When I Debug cmwx1zzabz_0xx, I get a hard fault somewhere near a call to HAL_PWR_EnterSLEEPMode(). It happens just after all the init code, somewhere in the first call to MX_LoRaWAN_Process(). If I step into MX_LoRaWAN_Process() and continue stepping, there is no fault.

Note that I commented out the calls to DBG_Disable() and DBG_ProbesInit() in SystemApp_Init() since they drop the ST-Link connection over USB.

[Andrew Neil]

How to debug Cortex-M Hard Faults.

[CCP]

Thanks for the useful article. I recompiled with optimizations off. The PC after the Hard Fault suggests this line in HAL_PWR_EnterSTOPMode():
...

/* Select Stop mode entry --------------------------------------------------*/
if(STOPEntry == PWR_STOPENTRY_WFI)
{
  /* Request Wait For Interrupt */
  __WFI();
}
else
{
  /* Request Wait For Event */
  __SEV();
  __WFE();
  __WFE();
}


/* Reset SLEEPDEEP bit of Cortex System Control Register */
CLEAR_BIT(SCB->SCR, SCB_SCR_SLEEPDEEP_Msk);

The request waits for event before executing the problem CLEAR_BIT macro. If I set a breakpoint on it, run to it and continue, the fault doesn't occur.

I tried replacing the CLEAR_BIT macro by reading the register to a local variable, clearing the bit in the variable and writing back to the register. This appears to fix the problem, but only if I build with Optimizations off (-O0). Any suggestions?

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Edited to apply source code formatting - please see How to insert source code for future reference.