Missing Interrupts on GPIOE PORT events

[wen jin zhang]

we're using Mbed for NRF51822. our board using 2 GPIOs interrupt.

problem: the Rise edge did not generate the Interrupt event: set EVENTS_PORT. I try uisng while, but it did not working: volatile uint32_t newVal = NRF_GPIO->IN;

    while ( (NRF_GPIOTE->EVENTS_PORT != 0) && ( (NRF_GPIOTE->INTENSET & GPIOTE_INTENSET_PORT_Msk) != 0) ){
        newVal = NRF_GPIO->IN;
//    if ( (NRF_GPIOTE->EVENTS_PORT != 0) && ( (NRF_GPIOTE->INTENSET & GPIOTE_INTENSET_PORT_Msk) != 0) ){
        NRF_GPIOTE->EVENTS_PORT = 0;
        setisrcheck001(1);
        for(uint8_t i=0;i<31;i++){
            if(channel_ids[i]>0){
                if(channel_enabled[i]){
                    if( ((newVal>>i)&1)  && ( ( (NRF_GPIO->PIN_CNF[i] >>GPIO_PIN_CNF_SENSE_Pos) & GPIO_PIN_CNF_SENSE_Low) != GPIO_PIN_CNF_SENSE_Low) && ( (portRISE>>i)&1) ){
                            irq_handler(channel_ids[i], IRQ_RISE);            
                    }                    
                    else if( ( ((newVal>>i)&1) == 0) && ( ( (NRF_GPIO->PIN_CNF[i] >>GPIO_PIN_CNF_SENSE_Pos)&GPIO_PIN_CNF_SENSE_Low) == GPIO_PIN_CNF_SENSE_Low) && ( (portFALL>>i)&1) ){
                            irq_handler(channel_ids[i], IRQ_FALL);
                    }                    
                }

                if(NRF_GPIO->PIN_CNF[i] &GPIO_PIN_CNF_SENSE_Msk){
                    NRF_GPIO->PIN_CNF[i] &= ~(GPIO_PIN_CNF_SENSE_Msk);
                                         
                    if(newVal>>i &1){
                         NRF_GPIO->PIN_CNF[i] |= (GPIO_PIN_CNF_SENSE_Low     << GPIO_PIN_CNF_SENSE_Pos) ;
                    }
                    else{
                         NRF_GPIO->PIN_CNF[i] |= (GPIO_PIN_CNF_SENSE_High     << GPIO_PIN_CNF_SENSE_Pos) ;
                    }
                }
            }
        }
        setisrcheck001(0);
    }

the Rise edge of RED signal should generate another interrupt. but seem failed.

Question:

1. what's condition to generate EVENTS_PORT in GPIOTE_IRQHandler() process? it' seem just clear EVENTS_PORT not enough.
2. how the GPIOE EVENTS_PORT generate when multi-GPIOs rise and fall ?

[Hung Bui]

@wen jin zhang :

1. GPIOTE PORT event generated on the rising edge of DETECT signal. Please have a look at section 15.1.2

2)DETECT signal is common signal when multiple pins are configured with SENSE mechanism. The DETECT signal is only cleared when all of the pin with SENSE mechanism is inactive. So if there still one pin is active, you won't be able to receive another interrupt on GPIOTE PORT event.

It's hard for me to understand the red signal. Could you capture another trace which may show the issue more clearly ?

[Hung Bui]

@Wen: When 2 GPIOs with SENSE mechanism is active at the same time. You only have one interrupt for both of them because DETECT signals of each GPIO pins are connected together. There is only one DETECT signal for all pins. So as long as there is one GPIO pin is active, other GPIO pin won't be able to trigger another GPIOTE PORT event, even if you clear PORT even.

What you can do is to switch off all other GPIOTE pins sense mechanism when you are in GPIOTE IRQ Handler. Then you flip the sense level of the pin that cause the DETECH signal to high. At this point the DETECT level should be low, and ready for another interrupt if there is.

After that you can turn the SENSE mechanism back on other pins.

This way you can make sure other change on other pins can trigger another GPIOTE PORT event.