ST意法半导体中文论坛利用stm32输出可调的PFM波，但ADC不起作用！！

利用stm32输出可调的PFM波，但ADC不起作用！！

jasonyeh 提问时间：2015-3-22 09:43 /

问答
是否解决:

本人刚学STM32，想用stm32输出可调的PFM波，通过一个可调电阻来调节PFM波，但ADC不起作用，无论怎么调都还是输出300KHz的PFM波，即ADC为0，下面是程序，请大侠们指教。

int main(void)
{
      u32 ad1=0;
      u32 ad2=0;

      RCC_Configuration();
GPIO_Configuration();
      ADC_Configuration();
Tim1_Configuration();

      while(1)
      {
            ad1=ADC_GetConversionValue(ADC1);
            ad2=ad1*3.3/4095;

            if(ad2>3)
            {
                     TIM_SetAutoreload(TIM1,119);
                     TIM_SetCompare1(TIM1,60);       //设定占空比
            }
            if((ad2>=2.5)&&(ad2<=3))
            {
                     TIM_SetAutoreload(TIM1,99);
                     TIM_SetCompare1(TIM1,50);       //设定占空比
            }
            if((ad2>=2)&&(ad2<=2.5))
            {
                     TIM_SetAutoreload(TIM1,79);
                     TIM_SetCompare1(TIM1,40);       //设定占空比
            }
            if((ad2>=1.5)&&(ad2<=2))
            {
                     TIM_SetAutoreload(TIM1,59);
                     TIM_SetCompare1(TIM1,30);       //设定占空比
            }
            if(ad2<1.5)
            {
                     TIM_SetAutoreload(TIM1,39);
                     TIM_SetCompare1(TIM1,20);       //设定占空比
            }

      }
}
void GPIO_Configuration(void)       //端口初始程序,可初始化多组管脚，串口要用到PA9、10做输入输出
{
      /*输出管脚初始化*/
      GPIO_InitTypeDef GPIO_InitStructure;
      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;       //
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
      /*初始化相应的GPIO*/
      GPIO_Init(GPIOA, &GPIO_InitStructure);

//       输入管脚初始化
      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
//       初始化相应的GPIO
      GPIO_Init(GPIOB, &GPIO_InitStructure);

      //ADC输入
      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 ;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
      GPIO_Init(GPIOC, &GPIO_InitStructure);

}
void RCC_Configuration(void)       //时钟初始程序
{ SystemInit();       //系统时钟频率72MHz          /*打开GPIOX使用的GPIO的时钟使能*/
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
RCC_ADCCLKConfig(RCC_PCLK2_Div6);//6分频为12M}

void Tim1_Configuration(void)
{             TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_BDTRInitTypeDef TIM_BDTRInitStructure; //第三步，定时器基本配置
TIM_TimeBaseStructure.TIM_Period=150-1;          // 自动重装载寄存器的值
TIM_TimeBaseStructure.TIM_Prescaler=6-1;          // 时钟预分频数
TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; // 采样分频
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;//向上计数
TIM_TimeBaseStructure.TIM_RepetitionCounter=0;//重复寄存器，用于自动更新pwm占空比
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);       //第四步pwm输出配置
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM2;                   //设置为pwm1输出模式
TIM_OCInitStructure.TIM_Pulse=75;                               TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_High;                //设置输出极性       TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable;       //使能该通道输出       //下面几个参数是高级定时器才会用到，通用定时器不用配置       TIM_OCInitStructure.TIM_OCNPolarity=TIM_OCNPolarity_High;       //设置互补端输出极性
TIM_OCInitStructure.TIM_OutputNState=TIM_OutputNState_Enable;//使能互补端输出
TIM_OCInitStructure.TIM_OCIdleState=TIM_OCIdleState_Reset;       //死区后输出状态
TIM_OCInitStructure.TIM_OCNIdleState=TIM_OCNIdleState_Reset;//死区后互补端输出状态
TIM_OC1Init(TIM1,&TIM_OCInitStructure);                                           //按照指定参数初始化       //第五步，死区和刹车功能配置，高级定时器才有的，通用定时器不用配置       TIM_BDTRInitStructure.TIM_OSSRState = TIM_OSSRState_Disable;//运行模式下输出选择
TIM_BDTRInitStructure.TIM_OSSIState = TIM_OSSIState_Disable;//空闲模式下输出选择
TIM_BDTRInitStructure.TIM_LOCKLevel = TIM_LOCKLevel_OFF;       //锁定设置
TIM_BDTRInitStructure.TIM_DeadTime = 42;                                        //死区时间设置
TIM_BDTRInitStructure.TIM_Break = TIM_Break_Disable;                //刹车功能使能
TIM_BDTRInitStructure.TIM_BreakPolarity = TIM_BreakPolarity_Low;//刹车输入极性
TIM_BDTRInitStructure.TIM_AutomaticOutput = TIM_AutomaticOutput_Enable;//自动输出使能
TIM_BDTRConfig(TIM1,&TIM_BDTRInitStructure);       //第六步，使能端的打开
TIM_Cmd(TIM1,ENABLE);                                                          //打开TIM2
TIM_CtrlPWMOutputs(TIM1, ENABLE);                                  //pwm输出使能，一定要记得打开}

void ADC_Configuration(void) //配置数模转换
{       ADC_InitTypeDef ADC_InitStructure;
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_InitStructure.ADC_ScanConvMode = DISABLE;//多通道扫描模式
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;//循环采样
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;//转换由软件而不是外部触发启动
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel = 1; //转换通道数量
ADC_Init(ADC1, &ADC_InitStructure);                //定义规则组
ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_239Cycles5);
ADC_Cmd(ADC1, ENABLE);//ADC使能
  ADC_ResetCalibration(ADC1);       //ADC复位
while(ADC_GetResetCalibrationStatus(ADC1));
ADC_StartCalibration(ADC1);       //ADC校准
while(ADC_GetCalibrationStatus(ADC1));
ADC_SoftwareStartConvCmd(ADC1, ENABLE);//启动ADC}