nrf52 PWM interrupt registers

[lvh831]

Hello,

I'm trying to create a single shot PWM pulse. So I short SEQEND0 to task_stop. I setup an interrupt on stop event.

It works and enters the IRQ handler. I tried to disable re-entering IRQ by clear the register INTENCLR but that didn't work.

It keeps looping into the IRQ handler while the PWM is already stopped. I thought entering the IRQ would automatically clear

out the interrupt flag. So I tried clear with the register INTEN and it sort of works. My counter is 2 somehow. The only sure way I can disable the

interrupt is calling NVIC to disable. Could you please show what is the right way to enable interrupt and clear our the interrupt for PWM? Thanks.

NRF_PWM0->SHORTS = PWM_SHORTS_SEQEND0_STOP_Enabled << PWM_SHORTS_SEQEND0_STOP_Pos;


//NRF_PWM0->INTEN = PWM_INTEN_STOPPED_Enabled << PWM_INTEN_STOPPED_Pos;

NRF_PWM0->INTENSET = PWM_INTENSET_STOPPED_Enabled << PWM_INTENSET_STOPPED_Pos;

NVIC_EnableIRQ(PWM0_IRQn); 

int counter = 0;
void PWM0_IRQHandler(void) {
    counter++;
    NRF_PWM0->INTENCLR = PWM_INTENCLR_STOPPED_Clear || PWM_INTENCLR_STOPPED_Pos;
    //NRF_PWM0->INTEN = PWM_INTEN_STOPPED_Disabled << PWM_INTEN_STOPPED_Pos;
    // this is weird! it got caught twice here
    //NRF_PWM0->INTEN = 0;
    //NVIC_DisableIRQ(PWM0_IRQn);
    //it looks like INTENCLR doesn't work while INTEN sort of works.
    // The best one is just to disable IRQ which is overkill.

}

[Susheel Nuguru]

It should not have happened that you configured the PWM to stop immediately after the sequence is finished. But I cannot see how you configured the rest of the PWM. Can you give the whole code snippet of the PWM configuration and I will try to figure out if it in fact produces more sequences than one or it is just some ARM interrupt configuration issue.

[lvh831]

Susheel, thank you. I found out the problem. Typo on bit masking || should be <<.