stm32f207呼吸灯没有效果！

只看该作者 · 2018-6-30 21:04

我的led灯接口为PD0,低电平时亮。想实现呼吸灯的效果，不知道哪里有问题，不起作用
int main(void)
{
  TIM3_PWMConfig();
  while(1);
}
void TIM3_PWMConfig(void)
{
      GPIO_InitTypeDef GPIO_InitStructure;
      TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
      TIM_OCInitTypeDef TIM_OCInitStructure;
      /* TIM3 IO configuration *************************************/
      /* Enable GPIOD clock */
      RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
      /* Connect TIM3 pin (PD0) to AF2 */
      GPIO_PinAFConfig(GPIOD, GPIO_PinSource0, GPIO_AF_TIM3);
      /* Configure TIM3 CH1 pin (PC6) as alternate function */
      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 ;
      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(GPIOD, &GPIO_InitStructure);
      /* TIM3 configuration */
      /* Enable TIM3 clock */
      RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
      /* Time base configuration */
      TIM_TimeBaseStructure.TIM_Period = 255;
      TIM_TimeBaseStructure.TIM_Prescaler = 1999;
      TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
      TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
      TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
      /* Configure CH1 in PWM1 Mode */
      TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
      TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
      TIM_OCInitStructure.TIM_Pulse = 0;
      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
      TIM_OC1Init(TIM3, &TIM_OCInitStructure);
      TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
      TIM_ARRPreloadConfig(TIM3, ENABLE);
      /* Enable TIM3 counter */
      TIM_Cmd(TIM3, ENABLE);
      TIM_ITConfig(TIM3,TIM_IT_Update, ENABLE);
      NVIC_Config_PWM();
}

中断函数
void TIM3_IRQHandler(void)
{
      static uint8_t pwm_index = 0;                      //用于PWM查表
      static uint8_t period_cnt = 0;             //用于计算周期数

      if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)       //TIM_IT_Update
      {
                     period_cnt++;
                     if(period_cnt >= 10)                                                                               //若输出的周期数大于10，输出下一种脉冲宽的PWM波
                     {

                              TIM3->CCR3 = indexWave[pwm_index];       //根据PWM表修改定时器的比较寄存器值
                              pwm_index++;                                                                                              //标志PWM表的下一个元素

                              if( pwm_index >=  40)                                                             //若PWM脉冲表已经输出完成一遍，重置PWM查表标志
                              {
                                    pwm_index=0;
                              }

                              period_cnt=0;                                                                                              //重置周期计数标志
            }
            TIM_ClearITPendingBit (TIM3, TIM_IT_Update);       //必须要清除中断标志位
      }
}

stm32f207呼吸灯没有效果！

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