PWM为什么没输出

只看该作者 · 2014-4-24 15:24

用STM32F101VC做PWM：
程序如下：
////////////////////////////////////////////
void Timer3Init(void)
{


  //RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
  /* Time base configuration */
  //--------------------For pwm--------------
  //----------第一步：配置时钟 ---------------
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
  //--------------------For pwm--------------
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC,ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);
  //TIM_InternalClockConfig(TIM3);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

  TIM_TimeBaseStructure.TIM_Period = 65535;
  TIM_TimeBaseStructure.TIM_Prescaler = 35;//8+1=9
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  /* Prescaler configuration */
//  TIM_PrescalerConfig(TIM3, 1, TIM_PSCReloadMode_Immediate);

  /* Output Compare Timing Mode configuration: Channel1 */
//  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Timing;
//  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Disable;
//  TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
//  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

//  TIM_OC1Init(TIM3, &TIM_OCInitStructure);

//  TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Disable);
  /* TIM IT enable */
//  TIM_ITConfig(TIM3, TIM_IT_Update  , ENABLE);
  /* TIM2 enable counter */
  TIM_Cmd(TIM3, DISABLE);
//  TIM_SelectOnePulseMode(TIM3, TIM_OPMode_Single);
// NVIC_InitStructure.NVIC_IRQChannel = TIM3_UP_IRQChannel;
  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQChannel;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);



  //------------For  PWM----------------------
  //-----------第二步，配置goio口-------------
GPIO_InitStructure2.GPIO_Pin=GPIO_Pin_6|GPIO_Pin_7|GPIO_Pin_8|GPIO_Pin_9;
GPIO_InitStructure2.GPIO_Speed=GPIO_Speed_50MHz;
GPIO_InitStructure2.GPIO_Mode=GPIO_Mode_AF_PP;                //设置为复用浮空输出
GPIO_Init(GPIOC,&GPIO_InitStructure2);
      /*********TIM1_CH1N 引脚配置********/
GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE);

//第三步，定时器基本配置
TIM_TimeBaseStructure.TIM_Period=1000-1;          // 自动重装载寄存器的值
TIM_TimeBaseStructure.TIM_Prescaler=72-1;          // 时钟预分频数
TIM_TimeBaseStructure.TIM_ClockDivision=0; // 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(TIM3, &TIM_TimeBaseStructure);

//第四步pwm输出配置
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;                   //设置为pwm1输出模式
TIM_OCInitStructure.TIM_Pulse=500;                                           //设置占空比时间
TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_Low;                //设置输出极性
TIM_OCInitStructure.TIM_OCNPolarity=TIM_OCNPolarity_High;       //设置互补端输出极性

//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_OutputState=TIM_OutputState_Enable;       //使能该通道输出
TIM_OCInitStructure.TIM_OutputNState=TIM_OutputNState_Enable;//使能互补端输出

TIM_OC1Init(TIM3,&TIM_OCInitStructure); //按照指定参数初始化
TIM_OC1PreloadConfig(TIM3,TIM_OCPreload_Enable);
//第四步pwm输出配置
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;                   //设置为pwm1输出模式
TIM_OCInitStructure.TIM_Pulse=500;                                           //设置占空比时间
TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_Low;                //设置输出极性
TIM_OCInitStructure.TIM_OCNPolarity=TIM_OCNPolarity_High;       //设置互补端输出极性
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_OutputNState=TIM_OutputNState_Enable;//使能互补端输出

TIM_OC2Init(TIM3,&TIM_OCInitStructure); //按照指定参数初始化
TIM_OC2PreloadConfig(TIM3,TIM_OCPreload_Enable);

//第四步pwm输出配置
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;                   //设置为pwm1输出模式
TIM_OCInitStructure.TIM_Pulse=500;                                           //设置占空比时间
TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_Low;                //设置输出极性
TIM_OCInitStructure.TIM_OCNPolarity=TIM_OCNPolarity_High;       //设置互补端输出极性

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_OutputNState=TIM_OutputNState_Enable;//使能互补端输出

TIM_OC3Init(TIM3,&TIM_OCInitStructure); //按照指定参数初始化
TIM_OC3PreloadConfig(TIM3,TIM_OCPreload_Enable);

   //第四步pwm输出配置
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;                   //设置为pwm1输出模式
TIM_OCInitStructure.TIM_Pulse=500;                                           //设置占空比时间
TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_Low;                //设置输出极性
TIM_OCInitStructure.TIM_OCNPolarity=TIM_OCNPolarity_High;       //设置互补端输出极性

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_OutputNState=TIM_OutputNState_Enable;//使能互补端输出

TIM_OC4Init(TIM3,&TIM_OCInitStructure); //按照指定参数初始化
TIM_OC4PreloadConfig(TIM3,TIM_OCPreload_Enable);
  //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


//第六步，使能端的打开
            //使能TIMx在ARR上的预装载寄存器
TIM_ClearITPendingBit(TIM3,TIM_IT_Update);
TIM_Cmd(TIM3,ENABLE);
//打开TIM2
TIM_ARRPreloadConfig(TIM3, ENABLE);//使能ARR预装载缓冲器
//下面这句是高级定时器才有的，输出pwm必须打开
TIM_CtrlPWMOutputs(TIM3, ENABLE);                                  //pwm输出使能，一定要记得打开

//------------For  PWM----------------------
}

我的PWM为什么没输出？用的是TIM3四个通道。