STM32 F207的PWM输入捕获频率和占空比 定时器, color

yuyang911220

看datasheet,发现定时器几大功能之一就是对PWM信号的捕获比较.说明定时器即可以产生PWM信号,还可以对外部的PWM信号捕获.

自己仿真一下吧,将D0脚作用PWM信号的输出,用定时器3调整其高低电平输出时间,就算是一路占空比可调的PWM信号了.
将定时器2的CH2作为PWM信号的输入脚,即GPIOA1脚,将D0接到A1脚上.

先配置一下吧

//GPIO配置
  RCC_AHBxPeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE); //A口
  RCC_AHBxPeriphClockCmd(RCC_AHB1Periph_GPIOD,ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);


  GPIO_PinAFConfig(GPIOA, GPIO_PinSource1,  GPIO_AF_TIM2);//A0口复用为定时器2
  
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //配置为复用脚
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);


  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_Init(GPIOD, &GPIO_InitStructure);


//两路定时器的配置,这个定时器的配置还是有玄机在里面的,等会再讲
void TIM3_Configuration(void)
{

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);

/* ---------------------------------------------------------------

PCLK1=120/4=30MHz

TIM2 CLK = 30MHz * 2 = 60MHz, Prescaler = 300, TIM3 counter clock = 50,周期就为4K,定时器时间是0.25mS

--------------------------------------------------------------- */

/* Time base configuration */

TIM_TimeBaseStructure.TIM_Period = 50;   


TIM_TimeBaseStructure.TIM_Prescaler =(300-1);

TIM_TimeBaseStructure.TIM_ClockDivision = 0;

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);


  /*----------------------------------------------------------------
  TIM IT enable  使能或者失能指定的TIM中断
  TIM3:  TIM 中断源
  TIM_IT_Update | TIM_IT_Trigger:  TIM 触发中断源
   ----------------------------------------------------------------*/

TIM_ITConfig(TIM3, TIM_IT_Update | TIM_IT_Trigger, ENABLE);


/* TIM3 enable counter 使能TIMx外设*/

TIM_Cmd(TIM3, ENABLE);  
}

//这个函数数F2的标准库自带的例子,大家可以自己去研究下
void TIM2_Configuration(void)
{

  TIM_ICInitTypeDef  TIM_ICInitStructure;
  
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
  

/* Time base configuration */

TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;   


TIM_ICInitStructure.TIM_ICPolarity =TIM_ICPolarity_Rising;

TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;

TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
  TIM_ICInitStructure.TIM_ICFilter = 0x0;
  TIM_PWMIConfig(TIM2, &TIM_ICInitStructure);


  /* Select the TIM2 Input Trigger: TI2FP2 */
  TIM_SelectInputTrigger(TIM2, TIM_TS_TI2FP2);


  /* Select the slave Mode: Reset Mode */
  TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Reset);


  /* Enable the Master/Slave Mode */
  TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable);


  /* TIM enable counter */


  /* Enable the CC2 Interrupt Request */
  TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);
  
  TIM_Cmd(TIM2, ENABLE);


}