DMCCTL register value change

Guillermo Fernandez

Hi experts,

We are suffering a system crash. It is very difficult to reproduce it but when this error appears the value of the register DMCCTL is wrong. The initial value of this register is 0x50006405, after the crash the value is set to 0x5000640B. This value affects directly to read latency. Obviously, we can't read anything OK from the DDR2 after the change of this value. Any idea about who is modifying the value of this register? One exception is running but we don't know if the exception modified the value of the DMCCTL register or if the change of this register caused the exception. Looking into the problem we could found last part of code which was executed. It was a loop but it had never accessed to the address of DMCCTL.

Thanks in advance.

over 15 years ago

0 Ki over 15 years ago

TI__Guru**** 479941 points

Hello,

Is this a CCS crash? If so, please provide the details as requested in the forum readme:

http://e2e.ti.com/support/development_tools/code_composer_studio/f/81/t/3131.aspx

Thanks

0 Guillermo Fernandez over 15 years ago in reply to Ki

Intellectual 385 points

Thank you for your fast reply. It is not a CCS crash, we can read all registers and we can debug the problem using CCS. The SW stops in an exception routine. I suppose it is a problem related to our SW but we have some doubts about who can change the value of DMCCTL. It could be very helpful to us in order to find the source of the problem.

Thank you.

0 Ki over 15 years ago in reply to Guillermo Fernandez

TI__Guru**** 479941 points

Depending on your environment, you may have tools to help with this issue. What CCS version, device and emulator are you using?

0 Guillermo Fernandez over 15 years ago in reply to Ki

Intellectual 385 points

We are using CCS3.3.77 environment, DM648 device and XDS560 (PCI) emulator.

Thank you.

0 Ki over 15 years ago in reply to Guillermo Fernandez

TI__Guru**** 479941 points

If it is a memory mapped register, one thing you can try is setting a data watchpoint so you can halt the target when the value changes and see where the program is when this change happens. This can help you determine the cause.

You can set a watchpoint from the Unified Breakpoint Manager (UBM) window in CCSv3.3

See:

AET: http://processors.wiki.ti.com/index.php/Advanced_Event_Triggering

UBM: http://processors.wiki.ti.com/index.php/Unified_Breakpoint_Manager

Thanks

0 Guillermo Fernandez over 15 years ago in reply to Ki

Intellectual 385 points

We have already set a watchpoint: the value of DMCCTL changes at the beginning of an exception service routine. Could the system (DSP BIOS...) change the value of this register automatically? We are sure that the problem is related to our SW but we think we are not accessing to this memory position.

Thank you.

0 Guillermo Fernandez over 15 years ago in reply to Guillermo Fernandez

Intellectual 385 points

Hi experts,

Could anybody help me? Is anybody able to answer the previous question?

Thanks in advance.

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DMCCTL register value change