回复【11楼】正点原子:
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原子哥，请问我用ADC123_IN1 ADC123_IN2 ADC123_IN2 也就是PA0 1 2 口分别显示同一路电压，  但为什么只有PA1是正确的（经过万用表测量）。其他两路都相差很大。 板子我看PA0 1  2 口都没接外设。
void  Adc_Init(void)
{    
  RCC->APB2ENR|=1<<2;    
GPIOA->CRL&=0XFFFFF000  
RCC->APB2ENR|=1<<9;    //ADC1?±??????   
RCC->APB2RSTR|=1<<9;   //ADC1????
RCC->APB2RSTR&=~(1<<9);//?????á??     
RCC->CFGR&=~(3<<14);   //·????ò×?????  
RCC->CFGR|=2<<14;        

ADC1->CR1&=0XF0FFFF;   //?¤×÷????????
ADC1->CR1|=0<<16;      //?????¤×÷????    0== 0000
ADC1->CR1&=~(1<<8);    //·??¨?è????   
ADC1->CR2&=~(1<<1);    //????×???????
ADC1->CR2&=~(7<<17);    
ADC1->CR2|=7<<17;    //?í??????×???  
ADC1->CR2|=1<<20;      //????????????·?(SWSTART)!!! ±???????????????????·?
ADC1->CR2&=~(1<<11);   //??????  
ADC1->SQR1&=~(0XF<<20);
ADC1->SQR1&=0<<20;     //1??×????????ò?ò???? ????????×??????ò?ò??1     
ADC1->SMPR2&=0XFFFFF000;//?¨??0,1,2,3???ù?±??????   
        ADC1->SMPR2|=7<<9;      //?¨??3  239.5????,?á?????ù?±???????á?????·??  
ADC1->SMPR2|=7<<6;      //?¨??2  239.5????,?á?????ù?±???????á?????·??  
ADC1->SMPR2|=7<<3;      //?¨??1  239.5????,?á?????ù?±???????á?????·??  
ADC1->SMPR2|=7<<0;      //?¨??0  239.5????,?á?????ù?±???????á?????·??  

ADC1->CR2|=1<<0;     //????AD×????÷  
ADC1->CR2|=1<<3;        //??????????×?  
while(ADC1->CR2&1<<3);  //??????×??á??     
ADC1->CR2|=1<<2;        //????AD??×?    
while(ADC1->CR2&1<<2);  //??????×??á??
//???????í???è??????????×?????????×??á???±??????????  
}   
//获取电压值
u16 Get_Adc(u8 ch)          //     ch  为  0   1   2  
{
//?è??×????ò??     
ADC1->SQR3&=0XFFFFFFE0;//???ò?ò??1 ?¨??ch
ADC1->SQR3|=ch;        
ADC1->CR2|=1<<22;       //???????ò×????¨?? 
while(!(ADC1->SR&1<<1));//????×????á??      
return ADC1->DR; //·???adc??
}