TMS320F28335: question about ISR

Julia Li

Part Number: TMS320F28335

Hi Champs,

I ask this for our customer. Customer have some question on ISR.

If interrupt nesting is disabled,

1. If the first EPWM ISR is running, and its second interrupt trigger comes again(the same interrupt ISR trigger), can the second ISR be triggered immediately? Or does it wait until the first ISR finish running before entering the second ISR?

2. If the answer to question 1 is the latter, how long does it take between the end of the first EPWM ISR and the second EPWM ISR trigger to ensure that the immediately response to the second interrupt?

3. If the answer to question 1 is the latter, will the second ISR trigger be lost or hang on?

4. If the answer to question 3 is hang on, how many interrupts can be hang on at most?

Thanks!

Best regards,

Julia

over 2 years ago

+1 Aswin P over 2 years ago

TI__Expert 7961 points

Hi Julia,

Julia Li said:
If the first EPWM ISR is running, and its second interrupt trigger comes again(the same interrupt ISR trigger), can the second ISR be triggered immediately? Or does it wait until the first ISR finish running before entering the second ISR?

The PIEACK bit for the interrupt group must be cleared at the end of the ISR. If the PIEACK bit is not cleared, the CPU will not receive any further interrupts from that group. The C28x CPU can only execute one thread at a time, It waits until the first ISR finish running before entering the second ISR.

Please go through the C28x Interrupt Response - No Nesting (Default Behavior) section in the following document for detailed information.

C28x Interrupt Nesting

Also there are few threads which has similar topics -

(+) TMS320F28379D: Question about interrupts: Are interrupts processed in series? Can they be processed in parallel on one CPU? - C2000 microcontrollers forum - C2000︎ microcontrollers - TI E2E support forums

Thanks

Aswin

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28335: question about ISR