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TMS320F28235: interrupt void ILLEGAL_ISR(void) // Illegal operation TRAP

Curtis Randall
Prodigy 90 points
Part Number: TMS320F28235

I have been using the TMS320F28235 for years now.

Recently having a problem:

interrupt void ILLEGAL_ISR(void)   // Illegal operation TRAP

It has been working on Silicon Revision CA, and now I get this ILLEGAL_ISR ONLY on Silicon Revision G4A.

 

I think it has something to do with:

5.1.1 PIE: Spurious Nested Interrupt After Back-to-Back PIEACK Write and Manual CPU Interrupt
Mask Clear Usage Note
Revision(s) Affected: 0, A

What changed in the Silicon Revision?

Please help?

 

Thank you,

Curtis Randall

  • 0
    TI__Guru** 113875 points
    Hi Curtis,

    That particular usage note apply to all version of silicon so I don't think that should be the issue. Have you seen this issue on just one device or across multiple devices? Did you try to step through the code in CCS to see which function/code is causing this issue?

    Regards,

    Vivek Singh
  • 0 in reply to Vivek Singh
    Prodigy 90 points

    Hello Vivek,

    I have disabled the Nested Interrupts and still get an Illegal-Instruction Trap.

    I only have an issue with the G4A Wafer Fab Code, when running out of FLASH. The C4 Wafer Fab Code, always works.

    When code is downloaded with the emulator to RAM it always works on all Chips.

    When I step through the code in CCS it always works, only happens when running full speed.

    Thanks,

    Curtis Randall

  • 0 in reply to Curtis Randall
    TI__Guru** 113875 points

    Do you get issue only at full speed? Can you try slowing down the SYSCLK and see if that resolves the issue? Also you can set a breakpoint inside ITRAP handler and then check the RPC to see from where it jumped to ITAP handler. See if RPC value is same all the time or it's random?

    Regards,

    Vivek Singh

  • 0 in reply to Vivek Singh
    Prodigy 90 points
    Hello Vivek,

    I found the problem.
    The CA Wafer Fab Code only requires a 20mSecond XRS reset pulse at power up to work.
    The G4A Wafer Fab Code has this issue with less than a 300mSecond XRS reset pulse at power up.
    The G4A Wafer Fab Code works with greater than a 500mSecond XRS reset pulse at power up.

    Thanks for your time,
    Curtis Randall