單片機TM4C123學習（十）：ADC采樣模塊

1.頭文件

#include "tiva_adc.h"                // ADC

2.引腳

3.初始化

// ADC初始化
// 光敏電阻（PE0）為通道3，存在序列0中，硬件平均為8個點
adc_init(TIVA_ADC1 , Channel_3, Sequence0, GPIOE, Pin0, 8);

  // 滑動變阻器為通道2
  adc_init(TIVA_ADC1 , Channel_2, Sequence1, GPIOE, Pin1, 8);

//具體函數內容
//channel:0-11
//sequence:0-3

void adc_init(uint32_t adc, uint32_t channel, uint32_t sequence, uint32_t GPIO, uint32_t PIN,
                            int average_num)
{
    //參數轉換
    uint32_t adc_base;
    uint32_t adc_gpio;
    //選擇ADC0或ADC1
    if(adc == TIVA_ADC0)
        adc_base = ADC0_BASE;
    else if(adc == TIVA_ADC1)
        adc_base = ADC1_BASE;
    
    //選擇GPIO
    switch(GPIO)
    {
        case GPIOA:{adc_gpio = SYSCTL_PERIPH_GPIOA;break;}
        case GPIOB:{adc_gpio = SYSCTL_PERIPH_GPIOB;break;}
        case GPIOC:{adc_gpio = SYSCTL_PERIPH_GPIOC;break;}
        case GPIOD:{adc_gpio = SYSCTL_PERIPH_GPIOD;break;}
        case GPIOE:{adc_gpio = SYSCTL_PERIPH_GPIOE;break;}
        case GPIOF:{adc_gpio = SYSCTL_PERIPH_GPIOF;break;}
    }
  SysCtlPeripheralEnable(adc);    // 開ADC0/ADC1
  GPIOPinTypeADC(GPIO, PIN);        // 選擇管腳
  // 開啟ADC
  // adc:ADC0 或 ADC1
  // sequence: 選擇序列
  // 最后一個參數：優先級
    ADCSequenceConfigure(adc_base, sequence, ADC_TRIGGER_PROCESSOR, 0);
    
  ADCHardwareOversampleConfigure(adc_base, average_num);    // 設置硬件8個數取一次均值
    
  ADCSequenceStepConfigure(adc_base, sequence, 0, channel | ADC_CTL_IE | ADC_CTL_END);
    
  // 使能ADCx sequencex 中斷
    if(adc == TIVA_ADC0)
        ADCIntRegister(adc_base, sequence, ADC0Handler);
    else
        ADCIntRegister(adc_base, sequence, ADC1Handler);
    
  ADCIntEnable(adc_base, sequence);
    if(adc == TIVA_ADC0)            // ADC0
    {
        switch(sequence)
        {
            case 0:IntEnable(INT_ADC0SS0);break;
            case 1:IntEnable(INT_ADC0SS1);break;
            case 2:IntEnable(INT_ADC0SS2);break;
            case 3:IntEnable(INT_ADC0SS3);break;
        }
    }
    else                                            // ADC1
    {
        switch(sequence)
        {
            case 0:IntEnable(INT_ADC1SS0);break;
            case 1:IntEnable(INT_ADC1SS1);break;
            case 2:IntEnable(INT_ADC1SS2);break;
            case 3:IntEnable(INT_ADC1SS3);break;
        }
    }
    ADCSequenceEnable(adc_base, sequence);    // 通道配置好之后進行只能
  ADCIntClear(adc_base, sequence);                // 清除中斷標志
}

4.獲取采樣值

// 獲取采樣值,0-4095,對應0-3.3V
    adc_val = adc_get_value(TIVA_ADC1, Sequence0)*3.3/4096;

// 具體函數內容

uint16_t adc_get_value(uint32_t adc, uint8_t sequence)
{
    if(adc == TIVA_ADC0)    // ADC0
    {
        ADCProcessorTrigger(ADC0_BASE, sequence);
        switch(sequence)
        {
            case Sequence0:    return ADC0_sequence0_value;
            case Sequence1:    return ADC0_sequence1_value;
            case Sequence2:    return ADC0_sequence2_value;
            case Sequence3:    return ADC0_sequence3_value;
            default:                 return 0;
        }
    }
    else                                    // ADC1
    {
        ADCProcessorTrigger(ADC1_BASE, sequence);
        switch(sequence)
        {
            case Sequence0:    return ADC1_sequence0_value;
            case Sequence1:    return ADC1_sequence1_value;
            case Sequence2:    return ADC1_sequence2_value;
            case Sequence3:    return ADC1_sequence3_value;
            default:                 return 0;
        }
    }
}