• State Resolved
  • Locked Locked
  • Replies 10 replies
  • Subscribers 30 subscribers
  • Views 608 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CCS/TMS570LC4357: Branch to _c_int00 From Reset Vector is Not Working

Vishwas Chandrashekar
Prodigy 180 points
Part Number: TMS570LC4357

Tool/software: Code Composer Studio

I observed something strange with the branch instruction “B _c_int00" preset in the reset vector 0x0000000. This instruction successful execution and control transfer to _c_int00 function seems to be dependent on the location of _c_int00 function in Flash.  In “Not working” case below, instruction “B _c_int00” execution is not happening and the PC is incrementing to the next instruction, which is “B Undefined Entry” in the reset vector.  CPSR.Mode = 1011, Supervisor, in "Not working" case. Unable to conclude why “B _c_int00” instruction is not executing when the _c_int00 function location in Flash is as per “Not working” case below.  

_c_int00 Address in Flash

"B _c_int00" instruction  at reset vector 0x00000000

0x0026F4DC

Working

0x0026F504

Working

0x0026F57C

Working

0x0026F66C

Working

0x0026F76C

Working

0x0026F7fC

Working

0x0026F800

Working

0x0026F808

Not working

0x0026F80C

Not working

0x0026F810

Not working

0x0026F824

Not working

0x0026F86C

Not working

0x0026F9E8

Not working

0x0026FAE8

Not working

0x0026FBE8

Not working

0x0026FC00

Not working

0x0026FC08

Working

0x0026FCE8

Working

0x0026FDE8

Working

0x0026FEE8

Working

I would like to know what is the issue here? Is it a CCS issue? or silicon issue? or am I missing anything?

CCS Version: 9.3.0.00012

Compiler version: TI v18.12.4.LTS

Regards,

Vishwas HC

  • 0
    TI__Guru**** 196776 points

    Hi Vishwas,

    For Hercules microcontrollers, the location of the exception vector table address is 0x00000000. The start address of _c_int00 needs to be 64-bit aligned. Do you check the memory to make sure the _c_int00 is programed to the address defined in your exception vector table?

  • 0 in reply to QJ Wang
    Prodigy 180 points

    Hi Wang,

    Yes, I did make sure address of the _c_int00 in Flash is as per table in my original post.

    I verified in map file as well as by having a break point at "B _c_int00" and decoding the Branch instruction opcode. I verified the content of memory location in memory browser to make sure _c_int00 location in Flash is as per my table above. As I explained in my original post Branch to _c_int00 from the reset vector is not happening in "Not working" cases. Flash address are correct and there is no overlap with any other section.

    Regards,

    Vishwas HC

  • 0 in reply to Vishwas Chandrashekar
    TI__Guru**** 196776 points

    I will try it, then come back to you

  • 0 in reply to QJ Wang
    TI__Guru**** 196776 points

    Hi Vishwas,

    Can you tell me how to program _c_int00() to the locations specified in your post? Isn't it aligned to 32-byte boundary?

  • 0 in reply to QJ Wang
    Prodigy 180 points

    Hi Wang,

    I am assigning ROM start address for my application in linker cmd file as 0x00201504. I defined global constants variables to get _c_int00() into a specific location in Flash.

    Initially when I defined some global constants, I observed behavior as explained in my above post for "Not working" case. Then I deleted some global constants and added more global constants in order to get _c_int00() location in Flash as per "Working" case.

    Regards,

    Vishwas HC   

  • 0 in reply to Vishwas Chandrashekar
    TI__Guru**** 196776 points

    Hello Vishwas,

    I am sorry I did not get your point. I tested one your not-working location (0x26F808), but it works as expected.

    I use "CINT00 : {HL_sys_startup.obj (.text)} > 0x0026F808" in Linker CMD file to place c_int00 to 0x26F808 (refer to my cmd file in the screenshot below):

  • 0 in reply to QJ Wang
    TI__Guru**** 196776 points

    same for another not working location: 0x0026F9E8

    The code runs to the breakpoint in _c_int00() without any issue. 

  • 0 in reply to QJ Wang
    Prodigy 180 points

    Hi Wang,

    Thanks. I will check this and get back to you.

    Regards,

    Vishwas HC

  • 0 in reply to Vishwas Chandrashekar
    TI__Guru**** 196776 points

    Hello Vishwas,

    Ok, let me know your test result.

  • 0 in reply to QJ Wang
    Prodigy 180 points

    Hi Wang,

    In my linker cmd file, align(32) for the Flash address is missing. I think, this is the reason for the issue I am observing. Thanks for your response. After adding align(32) for Flash, issue goes away. 

    As per documentation, align(32) directive aligns the Section Program Counter (SPC) at 32-byte boundary. However functions start address like 0x0026F504, 0x0026F57C, 0x0026F808 etc are not 32-byte aligned. With the align(32) in the linker cmd file, I do see many functions start address in the map file which are not 32-byte aligned.

    I am not understanding why adding align(32) in the linker cmd file resolves the issue. With align(32) in linker cmd file, will linker allocate functions in Flash with 32 byte aligned?. What is the purpose of align(32) in the linker cmd file? 

    Regards,

    Vishwas HC