TMS320F28035: Global variable in specific memory location (RAM) will be changed unexpectedly

Sheldon He

Part Number: TMS320F28035

Hi Expert,

My customer met this issue in their mass production project and issue IC is from their end customer return.

Issue description:

One of the F28035 IC's specific global variable will being changed to some random value in some working conditon. This issue can be 100% reproduced by powering up the IC and made the machine is some specifc working state (over current protection).

1. This issue will follow this IC in ABA test we have already done.

2. If we relocate the variable (keep this the only change in SW), to some other location like 0x00009cc0. This issue will disappear.

3. When this issue happend, we can re-write or re initiate this variable to fix it.

Do you have any idea or recommendations for us to further debug this issue?

Thanks

Sheldon

over 4 years ago

0 Veena Kamath over 4 years ago

TI__Mastermind 32655 points

Hi Sheldon,

Could it be because of stack overflow? The code might have have accidently written some value to the location where the global was stored.

To debug the issue, I would recommend adding a watchpoint at the global variable location, to figure out the code that does accidental write to this location.

Regards,

Veena

0 Sheldon He over 4 years ago in reply to Veena Kamath

TI__Expert 8585 points

Hi Veena,

We have tried to enlarge stack size from 0x300 to 0x5A0 but this issue still happens on one single device. Do you have further recommendations here?

Do you thinik we need to ask for a FA?

Thanks

Sheldon

0 Veena Kamath over 4 years ago in reply to Sheldon He

TI__Mastermind 32655 points

HI Sheldon,

Did you try keeping a watchpoint at the location? The CPU will be halted whenever there is a write access to that location. It could be that some application code accidently writing to this address.

Regards,

Veena

0 Sheldon He over 4 years ago in reply to Veena Kamath

TI__Expert 8585 points

Hi Veena,

We will try this as you advised.

May I know more details here, like:

1. When watch point is triggered, should I view memory and diassembly then?

2. Any other advice you have to debug this.

Thanks

Sheldon

0 Sheldon He over 4 years ago in reply to Veena Kamath

TI__Expert 8585 points

Hi Veena,

We tried to reproduce the issue with debugger connected to the board. But once high power is on, debugger connection will lose. We are trying to find some JTAG isolator. At the same time, any other method for us to debug this?

Thanks

Sheldon

0 Veena Kamath over 4 years ago in reply to Sheldon He

TI__Mastermind 32655 points

Hi Sheldon,

I am checking with the experts and will get back to you soon.

Regards,

Veena

0 MatthewPate over 4 years ago in reply to Veena Kamath

TI__Guru* 81560 points

Sheldon,

To better understand if this is isolated to a particular device or the code; do we know if see this behavior on multiple devices(programmed with the same FW)? Or is this just on one device?

You mentioned relocating the variable to a new memory address, 0x9CC0, can you give info on the original memory location?

It may also help if you can send the .map file that has the memory allocations for the program. Since this is customer info you can send to me via email vs posting to the E2E if that is a concern.

Best,

Matthew

0 Sheldon He over 4 years ago in reply to MatthewPate

TI__Expert 8585 points

Hi Matthew,

We only see this issue in one particular device programmed with this SW.

I will reach to you after I get these information.

Thanks

Sheldon

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28035: Global variable in specific memory location (RAM) will be changed unexpectedly