ADC问题

縋逐ЮDreams

初始化了两路ADC，自己用电位器测试了可以使用，电压在0--4096之间变化，但是接上传感器之后输出一直咂3700左右变化。

使用示波器直接测试传感器的输出也是正确的，有变化，但是接上单片机之后再测试就发现测试结果不对了，就稳定在了3700左右。

请问这是什么问题，下面贴上我的代码：
uint8_t adc_init(void)
{       
        uint8_t ret = 0;

       
        adc_config_t adcConfigStruct;
        adc_conv_seq_config_t adcConvSeqConfigStruct;
       
       
// Configure the power and clock for ADC.
  POWER_DisablePD(kPDRUNCFG_PD_ADC0);     /* Power on the ADC converter. */
  POWER_DisablePD(kPDRUNCFG_PD_VD7_ENA);  /* Power on the analog power supply. */
  POWER_DisablePD(kPDRUNCFG_PD_VREFP_SW); /* Power on the reference voltage source. */
  POWER_DisablePD(kPDRUNCFG_PD_TEMPS);    /* Power on the temperature sensor. */

// Enable the clock.
//  CLOCK_AttachClk(kFRO12M_to_MAIN_CLK);
  CLOCK_EnableClock(kCLOCK_Adc0); /* SYSCON->AHBCLKCTRL[0] |= SYSCON_AHBCLKCTRL_ADC0_MASK; */
       
//        IOCON_PinMuxSet(IOCON, 1, 0, IOCON_MODE_INACT | IOCON_FUNC0 | IOCON_ANALOG_EN | IOCON_INPFILT_OFF);
       
// Calibration
        if (ADC_DoSelfCalibration(ADC0))
        {
                ;
        }
        else
        {
                return 0;
        }

        /* Configure the converter. */
        adcConfigStruct.clockMode = kADC_ClockSynchronousMode; /* Using sync clock source. */
        adcConfigStruct.clockDividerNumber = 1;                /* The divider for sync clock is 2. */
        adcConfigStruct.resolution = kADC_Resolution12bit;
        adcConfigStruct.enableBypassCalibration = false;
        adcConfigStruct.sampleTimeNumber = 0U;
        ADC_Init(ADC0, &adcConfigStruct);

        /* Use the sensor input to channel 0. */
        ADC_EnableTemperatureSensor(ADC0, true);

        /* Enable channel 0's conversion in Sequence A. */
        adcConvSeqConfigStruct.channelMask = (1U << ADC_CHANNEL4_NUM | 1U << ADC_CHANNEL5_NUM); /* Includes channel 0. */
        adcConvSeqConfigStruct.triggerMask = 0U;
        adcConvSeqConfigStruct.triggerPolarity = kADC_TriggerPolarityNegativeEdge;
        adcConvSeqConfigStruct.enableSingleStep = false;
        adcConvSeqConfigStruct.enableSyncBypass = false;
        adcConvSeqConfigStruct.interruptMode = kADC_InterruptForEachSequence;
        ADC_SetConvSeqAConfig(ADC0, &adcConvSeqConfigStruct);
        ADC_EnableConvSeqA(ADC0, true); /* Enable the conversion sequence A. */
       
//        /* Enable channel 0's conversion in Sequence A. */
//        adcConvSeqConfigStruct.channelMask = (1U << ADC_CHANNEL5_NUM); /* Includes channel 0. */
//        adcConvSeqConfigStruct.triggerMask = 0U;
//        adcConvSeqConfigStruct.triggerPolarity = kADC_TriggerPolarityNegativeEdge;
//        adcConvSeqConfigStruct.enableSingleStep = false;
//        adcConvSeqConfigStruct.enableSyncBypass = false;
//        adcConvSeqConfigStruct.interruptMode = kADC_InterruptForEachSequence;
//        ADC_SetConvSeqAConfig(ADC0, &adcConvSeqConfigStruct);
//        ADC_EnableConvSeqA(ADC0, true); /* Enable the conversion sequence A. */
       
        ret = 1;
        return ret;
}



uint16_t adc_read(uint16_t num)
{

        ADC_DoSoftwareTriggerConvSeqA(ADC0);
        /* Wait for the converter to be done. */
        while (!ADC_GetChannelConversionResult(ADC0, num, &gAdcResultInfoStruct))
        {
        }       
       
        return (gAdcResultInfoStruct.result&0x0FFF);
}



引脚也是初始化了的。使用MCUXpresso Config Tools v4.0初始化的

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縋逐ЮDreams

我加了一个电位器之后，通过电位器输出再与传感器连接之后，总算有了数值变化，变化的幅度有1000多了，我也不清楚造成最原始ad值读取不出来的原因是什么？期望有人能解答？

噬猎者

IOCON初始化模式0
可以参考我的寄存器

1. #define ADC_RESOL_BIT        12        //12位ADC转换
   
2. void ADC_Init(void)//ADC初始化
   
3. {
   
4.         uint32 i=0;
   
5.         uint32_t ctrl;
   
6.         uint32_t tmp;
   
7. //1.配置管脚功能(ADC管脚采用 模拟 )
   
8.         PORT0_IOCON29 = 0x01;//adc0
   
9. //        PORT1_IOCON1 = 0x01;//adc4
   
10. //        PORT1_IOCON2 = 0x01;//adc5
    
11. //        PORT1_IOCON3 = 0x01;//adc6
    
12.        
    
13.        
    
14. //2.ADC配置
    
15.         Chip_SYSCON_PowerUp(SYSCON_PDRUNCFG_PD_ADC0 | SYSCON_PDRUNCFG_PD_VDDA_ENA | SYSCON_PDRUNCFG_PD_VREFP);//启动ADC模块供电电源
    
16.         Chip_Clock_EnablePeriphClock(SYSCON_CLOCK_ADC0);//开启ADC0时钟
    
17.         Chip_SYSCON_PeriphReset(RESET_ADC0);//复位ADC0
    
18.         SYSCON_BASE_PTR->ADCCLKSEL = (uint32_t) 0x00;
    
19.         SYSCON_BASE_PTR->ADCCLKDIV = 0x1;       
    
20.         ADC_SEQA_CTRL = 0x00;
    
21.         ADC_SEQB_CTRL = 0x00;
    
22.         //配置ADC管脚：需要修改这个！！！
    
23.         ADC_SEQA_CTRL = (0x1<<0)|0xa0000000;        // 信道11:0 |0xa0000000  启动信道0
    
24.        
    
25. //ADC分辨率设置：//3-12 2-10 1-8 0-6
    
26. #if ADC_RESOL_BIT == 12
    
27.         ADC_CTRL = ((0x3)<<9)|0xFF;
    
28. #elif ADC_RESOL_BIT == 10
    
29.         ADC_CTRL = ((0x2)<<9)|0xFF;
    
30. #elif ADC_RESOL_BIT == 8
    
31.         ADC_CTRL = ((0x1)<<9)|0xFF;
    
32. #else
    
33.         ADC_CTRL = ((0x0)<<9)|0xFF;
    
34. #endif       
    
35.         ADC_STARTUP = 0x1;
    
36.         for ( i = 0; i < 0x10; i++ ) {}       
    
37. //校准
    
38.         //1,设置ADC频率为30MHz       
    
39.         ctrl = ADC_CTRL & 0x00007fff;
    
40.         tmp = ctrl;
    
41.         tmp &= ~(1 << 8);               
    
42.         ADC_CTRL = tmp | 0x63;
    
43.         //2,启动校准       
    
44.         ADC_CALIBR = 0x01;
    
45.         i = 0xF0000;
    
46.         while ( (ADC_CALIBR & 0x01) && --i );
    
47.         //3,设置频率为原频率       
    
48.         ADC_CTRL = ctrl;
    
49. //启动ADC               
    
50.         ADC_STARTUP = 0x3;
    
51.                
    
52. /*读取ADCn数据
    
53.                 ADC_SEQA_CTRL|=0x1<<26;
    
54.                 var[1] = (ADC_DAT3>>4)&0xFFF;
    
55.                 var[2] = (ADC_DAT4>>4)&0xFFF;
    
56. */               
    
57. }

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