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Associate II
Sep 8, 2025 2:33 AM UTC
Solved

HardFault When accessing System memory from Cortex-M4 on STM32H755

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.
TDK
TDKBest answer
Sep 8, 2025 2:56 AM UTC

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

 

"If you feel a post has answered your question, please click ""Accept as Solution""."

2 replies

TDK
TDKBest answer
Sep 8, 2025 2:56 AM UTC

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

 

"If you feel a post has answered your question, please click ""Accept as Solution""."
JE2Author
Associate II
Sep 8, 2025 3:03 AM UTC

Oh! I had overlooked it.

Thanks for your quick reply!