[参考译文] TM4C1231H6PM：ADC 数字比较器输出

#define ADC_SEQUENCE_NUMBER 3

void adc_comparator_config(void) {
    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
    SysCtlPeripheralReset(SYSCTL_PERIPH_ADC0);

    GPIOPinTypeADC(GPIO_PORTD_BASE, GPIO_PIN_0);
    GPIOPinTypeGPIOOutput(GPIO_PORTD_BASE, GPIO_PIN_2);
    GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_2, GPIO_PIN_2);

    //
    // Disable the sequence.
    //
    ADCSequenceDisable(ADC0_BASE, ADC_SEQUENCE_NUMBER);
    ADCSequenceDisable(ADC0_BASE, 0);
    ADCIntClear(ADC0_BASE, ADC_SEQUENCE_NUMBER); // Clear any interrupts

    //
    // Reconfigure and enable the sequence.
    //
    ADCSequenceConfigure(ADC0_BASE, ADC_SEQUENCE_NUMBER,
                         ADC_TRIGGER_TIMER, 3);
    ADCSequenceStepConfigure(ADC0_BASE, ADC_SEQUENCE_NUMBER, 0,
                             ADC_CTL_CH7 | ADC_CTL_END | ADC_CTL_IE | ADC_CTL_CMP7);
	ADCSequenceEnable(ADC0_BASE, ADC_SEQUENCE_NUMBER);

    // Reset the ADC comparator
    ADCComparatorReset(ADC0_BASE, ADC_CTL_CH7, true, true);
    ADCComparatorIntClear(ADC0_BASE, ADC_SEQUENCE_NUMBER);
    
    // Configure the ADC comparator
    ADCComparatorConfigure(ADC0_BASE, ADC_CTL_CMP7,
                           ADC_COMP_INT_HIGH_ALWAYS);
    ADCComparatorRegionSet(ADC0_BASE, ADC_CTL_CH7, 1024, 3600); // High threshold = 3600mV
    ADCComparatorIntEnable(ADC0_BASE, ADC_SEQUENCE_NUMBER);
    
    // Register the interrupt handler
    IntMasterEnable();
    ADCIntRegister(ADC0_BASE, ADC_SEQUENCE_NUMBER, adc_comparator_int_handler);
    ADCIntEnable(ADC0_BASE, ADC_SEQUENCE_NUMBER);
    IntEnable(INT_ADC0SS3);

}

// Once interrupt trigger, get the ADC value and print.
void adc_comparator_int_handler(void) {
    ADCComparatorIntClear(ADC0_BASE, ADC_SEQUENCE_NUMBER);
    uint32_t pui32ADC0Value[8] = {0};
    ADCSequenceDataGet(ADC0_BASE, ADC_SEQUENCE_NUMBER, pui32ADC0Value);
    printf("ADC value: %d", pui32ADC0Value[0]);
}

// Enable hw timer to trigger the ADC in every 1ms
void hw_timer_init()
{
    SysCtlPeripheralEnable(SYSCTL_PERIPH_WTIMER1);

    TimerDisable(WTIMER1_BASE, TIMER_A);

    TimerConfigure(WTIMER1_BASE, TIMER_CFG_A_PERIODIC);
    TimerLoadSet(WTIMER1_BASE, TIMER_A, SysCtlClockGet() / 1000 * 1);
    TimerControlTrigger(WTIMER1_BASE, TIMER_A, true);
    TimerEnable(WTIMER1_BASE,TIMER_A);

}