TMS320F28235: Nested intrrupt caution in errata document

Oba

Hello,

I am investigating a failure case in my customer's application software.
Then I want to know the detail of the below caution descrived in the errata document to know if the root cause of this failure is this caution.

Why is DINT required before exiting ISR in this case? Could you tell me the mechanism of causing the undefined behavior?

Regards,
Oba

over 3 years ago

0 Hareesh Janakiraman over 3 years ago

TI__Guru* 95315 points

Obata-san,

I need to check with the Design team on this. May take a few days.

0 Hareesh Janakiraman over 3 years ago in reply to Hareesh Janakiraman

TI__Guru* 95315 points

Obata-san,

The following two posts provides all the answers to your question:

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/501828/instruction-rptb-seems-to-cause-pc-going-crazy

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/786643/compiler-tms320f28069-28069-caution-while-using-nested-interrupts-sprz342n-errata-explanation

0 Oba over 3 years ago in reply to Hareesh Janakiraman

TI__Genius 17795 points

Hello Hareesh,

Thanks for your reply.
As far as I read the posts you memtioned, it is related to RPTB function.
Because RPTB is supported by only FPU devices, I think F2823x doesn't have this problem. Correct?

Regards,
Oba

0 Hareesh Janakiraman over 3 years ago in reply to Oba

TI__Guru* 95315 points

Obata-san,

Let me check this.

+1 Hareesh Janakiraman over 3 years ago in reply to Oba

TI__Guru* 95315 points

Obata-san,

Your understanding is correct. Also note that the compiler will not generate, or accept, the RPTB instruction unless the fpu_support switch set to fpu32 (or fpu64).

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TMS320F28235: Nested intrrupt caution in errata document