Q: What are the common causes of STM32 hard faults and how to debug them?
Answer
Hard faults on STM32 typically result from: accessing unmapped memory (MPU violation) dividing by zero unaligned memory access executing from SRAM with cache enabled or stack overflow during exception handling. Use Keil/MDK Fault Analyzer or STM32CubeIDE fault analysis view to decode SCB->HFSR and CFSR registers. Set a memory breakpoint on the stack pointer to detect overflow. Ensure all interrupt handlers call proper handlers. On ARMv7-M hard faults can be upgradeable from other fault types – enable MemManage BusFault UsageFault via SCB->SHCRS for earlier diagnosis. For debug use SEGGER J-Link or ST-Link with unlimited breakpoints.
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