A Data Entry Exception occurs but without any visible reason. RM57 - TMDXRM57LHDK Dev Board

Jerome Beauvais

Hello,
I am working with the TI Pro Trace analyzer on TMDXRM57LHDK Dev Board.
I got a Data Entry Exception in a code which is fully tested. The Exceptions occurs after a BEQ instruction, but this part of code is currently used and without any problem.
The part of code is the following:

The breakpoint is set on data entry address:

The trace is the following:

Do you have an explanation?

Thanks for your help

Jerome

over 9 years ago

0 Charles Tsai over 9 years ago

TI__Guru**** 191886 points

HI Jerome,

Can you read out the DFSR (Data fault status register) and DFAR (Data Fault Address Register) in the CPU? I want to know what caused the error. It could be MPU or ECC related.

0 Jerome Beauvais over 9 years ago in reply to Charles Tsai

Expert 1780 points

Hi Charles,
Thanks you very much for your fast reply.
I will examine DFSR and DFAR and I could send you the result tomorrow.
Best regards
Jerome

0 Jerome Beauvais over 9 years ago in reply to Jerome Beauvais

Expert 1780 points

Hello Charles.

This screen shot give you the requested data.

Do you want something else ?

Thanks a lot for your help.

Jerome

0 Jerome Beauvais over 9 years ago in reply to Jerome Beauvais

Expert 1780 points

Charles,

Another information:

May be the problem comes from the register r0.

Kind Regards

0 Charles Tsai over 9 years ago in reply to Jerome Beauvais

TI__Guru**** 191886 points

Hi Jerome,

The CPU is reading from address 0x1FF1B0EA and this is an illegal address which causes the MPU background fault. Are you saying that the instruction at 0x001849DB LDR R0, [R0, #8] is the offending instruction? If this is the case can you please find out how the R0 was first loaded?

0 Jerome Beauvais over 9 years ago in reply to Charles Tsai

Expert 1780 points

Hi Charles,
I found why R0 load a wrong address.
The bug comes from another program which breaks a chain of pointers.
I did not know the role of DFSR and DFAR registers before, so you help me a lot to find the bug.
Thanks a lot.
Regards
Jerome

0 Charles Tsai over 9 years ago in reply to Jerome Beauvais

TI__Guru**** 191886 points

HI Jerome,
Glad that your problem is resolved!

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A Data Entry Exception occurs but without any visible reason. RM57 - TMDXRM57LHDK Dev Board