TMS320F28388D: Access to Stack Pointer in C code.

Dorion Carr

Part Number: TMS320F28388D

We are getting a PIE interrupt and I would like to be able to dump the stack from C code. This is on CPU1/CPU2.

Everything I have read says that I cannot get access to the SP register. How would I do this from C code.

We have a .stack defined at 0x400 and we have access to that memory space but I need to know where the last know position is to dump the actually stack.

According to document spru430f.pdf Table 3-5 is shows how the registers are pushed onto the stack when an ISR Exception is called, how can I pop them off the stack so that we can dump them to a console?

Specifically we want the 7th byte in the push since this is the last known PC.

Dorion

over 4 years ago

0 KARTHIKEYAN RAJAMANICKAM over 4 years ago

TI__Genius 11645 points

Dorion,

From what I understand you are interested to know from where you jumped on to that particular interrupt and dump the same every time that interrupt occurs.

You need to write assembly code to access/get the stack pointer and just read the contents of the respective memory location by offsetting the location.

This needs to the done at the very beginning for it to work reliably.

0 Dorion Carr over 4 years ago in reply to KARTHIKEYAN RAJAMANICKAM

Prodigy 240 points

Karthikeyan,

So we are receiving and exception interrupt and the SP is pointing at the last entry on the stack. I agree with you that I need to write some assembly code but I am not sure how to do it.

Do you have any example code?

void ISRExceptionFunct()

{

int16_t stackP
asm(" MOV #stackP, SP")

}

This doesn't work I get compile errors but in the assembly code it cannot find the C variable stackP. I have also put an UNDERSCORE in front of stackP.

Examples would be good.

Dorion

0 Lori Heustess over 4 years ago in reply to Dorion Carr

TI__Guru* 92740 points

Hello,

Please see the last response on this thread for a C-Callable assembly routine that returns the content of SP:

https://e2e.ti.com/support/microcontrollers/c2000/f/171/t/592314?CCS-TMS320F28069F-get-stack-pointer-postion

Regards

Lori

C2000™︎ microcontrollers

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TMS320F28388D: Access to Stack Pointer in C code.