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今天做了一个小实验：STM32F407的定时器2输出4路PWM波。程序如下：

/********************************************************************
函数功能：配置定时器2输出4路PWM波

入口参数：无

出口参数：无

备     注：主频168M，PWM周期100ms，占空比50%

*********************************************************************/
void  TIM2PWM_Config()
{
     GPIO_InitTypeDef  GPIO_InitStruct;
     TIM_TimeBaseInitTypeDef  TIM_TimeBaseInitStruct;
     TIM_OCInitTypeDef  TIM_OCInitStruct; 
 
    RCC_AHB1PeriphClockCmd (RCC_AHB1Periph_GPIOA,ENABLE );    //PA时钟使能    

    RCC_APB1PeriphClockCmd (RCC_APB1Periph_TIM2,ENABLE);      //定时器时钟使能 
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP ;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init (GPIOA,&GPIO_InitStruct);                          //引脚配置复用功能推挽输出
    GPIO_PinAFConfig (GPIOA,GPIO_PinSource0 | GPIO_PinSource1 | GPIO_PinSource2 |  GPIO_PinSource3,GPIO_AF_TIM2);
   TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up ;
   TIM_TimeBaseInitStruct.TIM_Period = 10000;
   TIM_TimeBaseInitStruct.TIM_Prescaler = 839;
   TIM_TimeBaseInit (TIM2,&TIM_TimeBaseInitStruct);   //增计数模式
   TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM1 ;
   TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_High ;
   TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;
   TIM_OCInitStruct.TIM_Pulse =  5000;   

   TIM_OC1Init(TIM2,&TIM_OCInitStruct);
   TIM_OC2Init(TIM2,&TIM_OCInitStruct);
   TIM_OC3Init(TIM2,&TIM_OCInitStruct);
   TIM_OC4Init(TIM2,&TIM_OCInitStruct);             //配置四个通道
   TIM_OC1PreloadConfig(TIM2,TIM_OCPreload_Enable);
   TIM_OC2PreloadConfig(TIM2,TIM_OCPreload_Enable);
   TIM_OC3PreloadConfig(TIM2,TIM_OCPreload_Enable);
   TIM_OC4PreloadConfig(TIM2,TIM_OCPreload_Enable);
   TIM_Cmd (TIM2,ENABLE);                             //使能定时器   
}

最终的效果就是，木有任何波形输出。大家看看能否说出问题出在哪里....答案回帖可见哦！！！

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