TMS570LS1224: Counting nested interrupt

Gabriel Berthiaume

Part Number: TMS570LS1224

I want to check dynamically if my function has been called from an ISR.

For example, in the FreeRTOS port for the PIC32 you can use:

#define IN_ISR()   uxInterruptNesting > 0 ? True : False

Is there a TMS570's special register that counts nested interrupt that I could poll?

Thanks,

Gabriel

over 5 years ago

0 Sunil Oak over 5 years ago

TI__Mastermind 49120 points

Gabriel,

Cortex R4/5 does not support interrupt nesting inherently. If you do need nested interrupts it needs to be managed completely by the application code. There is no hardware mechanism to aid with this other than the pending interrupt status flags.

Regards,

Sunil

0 Sunil Oak over 5 years ago in reply to Sunil Oak

TI__Mastermind 49120 points

This application note could be handy:

0 Gabriel Berthiaume over 5 years ago in reply to Sunil Oak

Intellectual 360 points

> Cortex R4/5 does not support interrupt nesting inherently.
> There is no hardware mechanism to aid with this other than the pending interrupt status flags.

My goal is to have a boolean answer to the question: "Am-I in an ISR right now?".

To answer this question, could we poll the current Operating Modes instead? (If we are in IRQ mode, I know I'm in an ISR.)

Thanks for your help.

Gabriel

0 Sunil Oak over 5 years ago in reply to Gabriel Berthiaume

TI__Mastermind 49120 points

Sorry I misunderstood your question before. Sure, you can read the CPSR mode bits to identify if you are in the IRQ mode.

0 Gabriel Berthiaume over 5 years ago in reply to Sunil Oak

Intellectual 360 points

Thanks for your support.
For those searching for the same information, here's a code snippets using the sys_code.h TI SDK API:

uint32_t const psr = _getCPSRValue_();
uint8_t const mode = (psr & 0x1F);
bool isInIRQ = (mode == 18);   //< See ARM CORTEX-R4F Technical Ref.

Have a great day
Gabriel.

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TMS570LS1224: Counting nested interrupt