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Explorer II
September 8, 2025
Solved

HardFault When accessing System memory from Cortex-M4 on STM32H755

  • September 8, 2025
  • 2 replies
  • 318 views

I'm using a NUCLEO-H755ZI-Q board.

 

I tried to read following address.

  • TEMPSENSOR_CAL1_ADDR (0x1FF1E820UL)
  • TEMPSENSOR_CAL2_ADDR (0x1FF1E840UL)

But I can't.

 it causes HardFault interrupt.

I also tried to read the area from Debugger.

Debugger said 

Failed to execute MI command:

-data-evaluate-expression *((short*)0x1FF1E820)

Error message from debugger back end:

Cannot access memory at address 0x1ff1e820

 

But it is possible from Cortex-M7.

 

I tried other System Memory area, But I can't.

I think Cortex-M4 cannot access System memory area without special sequence.

How do I access the area form Cortex-M4?

 

Someone, please help me.

    This topic has been closed for replies.
    Best answer by TDK

    The 0x1FF00000 area is Reserved on the M4 core and cannot be accessed on the M4 core. It can only be accessed by the M7 core.

    TDK_0-1757300126846.png

     

    2 replies

    TDKAnswer
    Super User
    September 8, 2025

    The 0x1FF00000 area is Reserved on the M4 core and cannot be accessed on the M4 core. It can only be accessed by the M7 core.

    TDK_0-1757300126846.png

     

    JE2Author
    Explorer II
    September 8, 2025

    Oh! I had overlooked it.

    Thanks for your quick reply!