FrequencyIn_NVIC_Fail_Graceful

FrequencyIn_NVIC_Fail_Graceful

static uint8_t MAX_FREQUENCY = CONF_CPU_FREQUENCY / 512000;

void frequencyin_interrupt_handler(uint8_t index) {
    Tc* tc = tc_insts[index];
    if (!tc->COUNT16.INTFLAG.bit.MC0) return; // false trigger

    pulseio_frequencyin_obj_t* self = active_frequencyins[index];

    // since we use EVACT.PPW, the Period is put into the CC[0] register
    // and that's all we need. CC[1] will contain the Pulse Width.
    uint16_t freq = tc->COUNT16.CC[0].bit.CC;
    self->frequency = freq;

    // we'll read CC[1] to make sure all of the INTFLAG registers are
    // also cleared. CC[1] will contain the Pulse Width measurement, which
    // we won't use. of course, we could use it in the future (replace PulseIn?).
    self->pulse_width = tc->COUNT16.CC[1].bit.CC;

    if (freq < MAX_FREQUENCY && freq > 0){
        self->max_frequency_captured = true;
    } else {
        self->max_frequency_captured = false;
    }

    if (tc->COUNT16.INTFLAG.bit.ERR) {
        err_count++;
        tc->COUNT16.INTFLAG.reg |= TC_INTFLAG_ERR;
    }
    if (tc->COUNT16.INTFLAG.bit.OVF) {
        ovf_count++;
        tc->COUNT16.INTFLAG.reg |= TC_INTFLAG_OVF;
    }
    //err_count += tc->COUNT16.INTFLAG.bit.ERR;
    //ovf_count += tc->COUNT16.INTFLAG.bit.OVF;
}

uint16_t common_hal_pulseio_frequencyin_get_item(pulseio_frequencyin_obj_t* self) {
    //common_hal_mcu_disable_interrupts();
    #ifdef SAMD21
    NVIC_DisableIRQ(self->TC_IRQ);
    NVIC_DisableIRQ(EIC_IRQn);
    #endif

    if (self->max_frequency_captured) { // we've experienced a capture above what we can detect
        //common_hal_mcu_disable_interrupts();
        common_hal_pulseio_frequencyin_pause(self); // pause any further captures
        //common_hal_mcu_enable_interrupts();
        #ifdef SAMD21
        NVIC_ClearPendingIRQ(self->TC_IRQ);
        NVIC_EnableIRQ(self->TC_IRQ);
        NVIC_ClearPendingIRQ(EIC_IRQn);
        NVIC_EnableIRQ(EIC_IRQn);
        #endif
        mp_raise_RuntimeError("Frequency captured is above capability. Capture Paused.");
    }

    //common_hal_mcu_enable_interrupts();
    #ifdef SAMD21
    NVIC_EnableIRQ(self->TC_IRQ);
    NVIC_EnableIRQ(EIC_IRQn);
    #endif

    //uint16_t value = CONF_CPU_FREQUENCY / self->frequency;
    //return value;
    return self->frequency;
}

void common_hal_pulseio_frequencyin_pause(pulseio_frequencyin_obj_t* self) {
    Tc *tc = tc_insts[self->tc_index];
    if (!tc->COUNT16.EVCTRL.bit.TCEI) {
        return;
    }
    tc->COUNT16.EVCTRL.bit.TCEI = 0;
    
    #ifdef SAMD21 // pause the EIC
    uint32_t masked_value = EIC->EVCTRL.vec.EXTINTEO;
    EIC->EVCTRL.vec.EXTINTEO = masked_value | (0 << self->channel);
    #endif
    return;
}