TIM通用定时器（二）：输出比较——翻转模式

一、基本概念理解

1. 输出比较：打开一个TIMx计数器，再打开TIMx的一路或几路输出比较器（共4路），都配置好以后，计数器开始计数，当计数器里的值和

                   比较寄存器里的值相等时，产生输出比较中断，在中断中将计数器中的值读出，与翻转周期相加再写道比较寄存器中，使得和

                   下一个事件有相同的翻转周期。

2. 举例说明：例如TIM时钟频率设置为12MHZ，输出比较寄存器中的自装载值为600（高电平或低电平计数值），则输出的PWM频率为

                   frequency = 12MHZ/（600*2）=10KHZ。

二、程序设计与分析

1.  TIM计数器和输出比较器的配置

uint16_t capture = 0;
extern __IO uint16_t CCR1_Val;
extern __IO uint16_t CCR2_Val;
extern __IO uint16_t CCR3_Val;
extern __IO uint16_t CCR4_Val;

 

 

void TIM_Configuration(void)
{

/* Time base configuration */
  TIM_TimeBaseStructure.TIM_Period = 65535;         //这里必须是65535
  TIM_TimeBaseStructure.TIM_Prescaler = 2;            //3分频
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;      //
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //向上计数模式

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);          //初始化TIM3

  /* Output Compare Toggle Mode configuration: Channel1 */ 
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;    //输出比较翻转模式
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;   //使能通道1
  TIM_OCInitStructure.TIM_Pulse = CCR1_Val;                       //待装入输出比较寄存器中的脉冲值       

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;         //输出为正逻辑
  TIM_OC1Init(TIM3, &TIM_OCInitStructure);        //写入配置

  TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Disable);          //使能或者失能TIMx在CCR1上的预装载寄存器

  /* Output Compare Toggle Mode configuration: Channel2 */
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR2_Val;

  TIM_OC2Init(TIM3, &TIM_OCInitStructure);

  TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable);

  /* Output Compare Toggle Mode configuration: Channel3 */
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR3_Val;

  TIM_OC3Init(TIM3, &TIM_OCInitStructure);

  TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Disable);

  /* Output Compare Toggle Mode configuration: Channel4 */
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR4_Val;

  TIM_OC4Init(TIM3, &TIM_OCInitStructure);

  TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Disable);

  /* TIM enable counter */
  TIM_Cmd(TIM3, ENABLE);      //开启计数器

  /* TIM IT enable */                //TIM1中断源设置，开启相应通道的捕捉比较中断
  TIM_ITConfig(TIM3, TIM_IT_CC1 | TIM_IT_CC2 | TIM_IT_CC3 | TIM_IT_CC4, ENABLE);

}

 

2.  时钟配置

3.  GPIO配置

4.  中断服务程序

void TIM3_IRQHandler(void)
{
  /* TIM3_CH1 toggling with frequency = 183.1 Hz */
  if (TIM_GetITStatus(TIM3, TIM_IT_CC1) != RESET)               //检查指定的TIM中断发生与否
  {
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC1 );               //清除TIMx的中断待处理位

    capture = TIM_GetCapture1(TIM3);                            //获得输入捕获值，即计数器中的计数值
    TIM_SetCompare1(TIM3, capture + CCR1_Val );        //将计数值加上翻转的脉冲值写入输出比较寄存器中，以保证下一个TIM事

                                                                                       //件也是相同的脉冲数
  
  }

  /* TIM3_CH2 toggling with frequency = 366.2 Hz */
  if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
  {
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
    capture = TIM_GetCapture2(TIM3);
    TIM_SetCompare2(TIM3, capture + CCR2_Val);

  }

  /* TIM3_CH3 toggling with frequency = 732.4 Hz */
  if (TIM_GetITStatus(TIM3, TIM_IT_CC3) != RESET)
  {
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC3);
    capture = TIM_GetCapture3(TIM3);
    TIM_SetCompare3(TIM3, capture + CCR3_Val);
  }

  /* TIM3_CH4 toggling with frequency = 1464.8 Hz */
  if (TIM_GetITStatus(TIM3, TIM_IT_CC4) != RESET)
  {
    TIM_ClearITPendingBit(TIM3, TIM_IT_CC4);
    capture = TIM_GetCapture4(TIM3);
    TIM_SetCompare4(TIM3, capture + CCR4_Val);
  }
}