AD这里遇到这样的问题

2万 · 2023-1-7 10:01

我现在用79F6488调一个项目,在AD这里遇到这样的问题。我打开了AD中断,如果一直检测固定的AD输入通道，则AD检测没问题，AD转换率也正确。但是我在AD中断里改变了AD检测通道的话，就不正常了,AD检测值为0,而且中断速率也完全不对，中断特别快。

2万 · 2023-1-7 10:09

相关代码如下:

void ADC_init(void)
{
REGCON = 0X03;       //3.3V VDDR
      //参考电压、输入通道
      ADCH = (3<<6);       //Vref = 0.4VDDR

      //根据ADC输入口配置相应IO
      ADCH |= BIT(4);       //P16 for AN3
      ADCH |= BIT(5);       //P10 for AVDD ref
      ADCH |= BIT(0);       //P11 P12

//设置ADC时钟
      ADT =  0XF4;    //adcclk=1Mhz，转换率250hz
      ADCDS = 0X00;       //双极性输出

      ADCON = 0x00;       //内部基准电压
      PGAM = 0;
      ChangeAdcChanle(0);

      ADCON |= BIT(7); //ADC EN
      ADC_IE(1);
}

u8 xdata g_AdcChsBuff[3]; //ADC输入通道及增益
#define ADC_INPUT(PGA_GAIN,INPUT_CHS)  (u8)((PGA_GAIN<<4)|INPUT_CHS)
g_AdcChsBuff[0] = ADC_INPUT(PGA_GAIN_1X,ADC_CHS_AN3);
g_AdcChsBuff[1] = ADC_INPUT(PGA_GAIN_1X,ADC_CHS_Vref_P);
g_AdcChsBuff[2] = ADC_INPUT(PGA_GAIN_32X,ADC_CHS_AIN0);

//切换AD通道
void ChangeAdcChanle(u8 chanle)
{
      u8 tmp;
      ADCON &= ~BIT(7);  //关AD
      tmp = PGAM & 0x0f;
      PGAM = (g_AdcChsBuff[chanle]&0xf0)|tmp;

      tmp = ADCON & 0xf0;
      ADCON = (g_AdcChsBuff[chanle]&0x0f) | tmp;
      ADCON |= BIT(7); //启动转换
}

//AD中断
void ADC_ISR(void) interrupt ADC_INT
{
      if(ADCON&BIT(6))
      {
         ADCON &= ~BIT(6);  //ADCIF
            //adc_value = ADDL;       //
            ((u8 *)&adc_value)[0] = ADDH;
            ((u8 *)&adc_value)[1] = ADDM;

            if(adcChsIndex >=3)
                     adcChsIndex =0;

            g_ADC_res[adcChsIndex] = adc_value;

            if(++adcChsIndex >= 3)
                     adcChsIndex = 0;
            ChangeAdcChanle(adcChsIndex);
            ADCIsrCnt++;
      }
}