STM32F407输出可调占空比PWM的问题

只看该作者 · 2017-6-14 11:32

如下程序，大家帮忙看下，为什么不能输出PWM，

void TIM4_CH1_init(u32 Freq,u16 Dutycycle)
{
      u32 time4_period;
      u32 time4_pulse;

      time4_period=1000000/(Freq*20)-1;
      time4_pulse=(time4_period+1)*Dutycycle/100;

      TIM_TimeBaseInitTypeDef TIM_TimeBaseStruct;
      GPIO_InitTypeDef  GPIO_InitStructure;
      TIM_OCInitTypeDef TIM_OCInitStructre;

      RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);


  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
//       GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
      GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOB,GPIO_PinSource6,GPIO_AF_TIM4);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4,ENABLE);
//       TIM_DeInit(TIM4);

      TIM_TimeBaseStruct.TIM_Prescaler=167;//Ô¤·ÖÆµ
      TIM_TimeBaseStruct.TIM_CounterMode=TIM_CounterMode_Up;//ÏòÉÏ
  TIM_TimeBaseStruct.TIM_Period=time4_period;//³õÖµ
  TIM_TimeBaseStruct.TIM_ClockDivision=0;
      TIM_TimeBaseInit(TIM4,&TIM_TimeBaseStruct);


      TIM_OCStructInit(&TIM_OCInitStructre);
      TIM_OCInitStructre.TIM_OCMode=TIM_OCMode_PWM1;
      TIM_OCInitStructre.TIM_OCNIdleState=TIM_OutputState_Enable;
      TIM_OCInitStructre.TIM_Pulse=time4_pulse;
      TIM_OCInitStructre.TIM_OCPolarity=TIM_OCPolarity_High;
      TIM_OC1Init(TIM4,&TIM_OCInitStructre);

      TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);
      TIM_ARRPreloadConfig(TIM4,ENABLE);

//       TIM_ClearFlag(TIM4, TIM_FLAG_Update);
//       TIM_ITConfig(TIM4, TIM_IT_Update,ENABLE);

      TIM_Cmd(TIM4,ENABLE);
}