TIMER门控模式控制PWM输出长度

时间：2024-04-20 16:35:57

TIMER门控模式控制PWM输出长度

参照一些网友代码做了些修改，由TIM4来控制TIM2的PWM输出长度，

采用主从的门控模式，即TIM4输出高时候TIM2使能输出

//TIM2 PWM输出，由TIM4来控制其输出与停止

//frequency_tim2：TIM2 PWM输出周期：KHz

//duty_tim2：TIM2 PWM占空比  0-100

//period_tim4: TIM4控制TIM2总周期，单位0.1ms

//duty_tim4: TIM4控制TIM2输出时间，单位0.1ms

void TIM2_CH3_PA2_PWM_TIM4_CH4_GATE( unsigned short int frequency_tim2,

  char duty_tim2, unsigned short int period_tim4, unsigned short int duty_tim4 )

{

  GPIO_InitTypeDef GPIO_InitStructure;

  TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

  TIM_OCInitTypeDef TIM_OCInitStructure;

  RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM2 | RCC_APB1Periph_TIM4, ENABLE );

  //使能定时器2时钟

  RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE );

  //使能GPIO外设和AFIO复用功能模块时钟

  //设置该引脚为复用输出功能,输出TIM2 CH3的PWM脉冲波形 GPIOA.2

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; //TIM2_CH3

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //复用推挽输出

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init( GPIOA, &GPIO_InitStructure );  //初始化GPIO

  //初始化TIM2

  TIM_TimeBaseStructure.TIM_Period = (  / frequency_tim2 );

  //设置在下一个更新事件装入活动的自动重装载寄存器周期的值,本身频率为1MHz，又分频器设置的下面一行

  TIM_TimeBaseStructure.TIM_Prescaler = (  -  );

  //设置用来作为TIMx时钟频率除数的预分频值，72MHz/72=1MHz

  TIM_TimeBaseStructure.TIM_ClockDivision = ;

  //设置时钟分割:TDTS = Tck_tim

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  //TIM向上计数模式

  TIM_TimeBaseInit( TIM2, &TIM_TimeBaseStructure );

  //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

  //初始化TIM2 Channel3 PWM模式

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

  //选择定时器模式:TIM脉冲宽度调制模式2

  TIM_OCInitStructure.TIM_Pulse = (  * duty_tim2 / frequency_tim2 );

  //(TIM_Period)*(duty/100) --> (1000/period)*(duty/100)

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

  //比较输出使能

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  //输出极性:TIM输出比较极性高

  TIM_OC3Init( TIM2, &TIM_OCInitStructure );

  //根据T指定的参数初始化外设TIM2 OC3

  TIM_OC3PreloadConfig( TIM2, TIM_OCPreload_Enable );

  //使能TIM2在CCR3上的预装载寄存器

  TIM_Cmd( TIM2, ENABLE );  //使能TIM2

  //初始化TIM4

  TIM_TimeBaseStructure.TIM_Period = period_tim4;

  //设置在下一个更新事件装入活动的自动重装载寄存器周期的值,本身频率为1MHz，又分频器设置的下面一行

  TIM_TimeBaseStructure.TIM_Prescaler = (  -  );

  //设置用来作为TIMx时钟频率除数的预分频值，72MHz/72=1MHz

  TIM_TimeBaseStructure.TIM_ClockDivision = ;

  //设置时钟分割:TDTS = Tck_tim

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  //TIM向上计数模式

  TIM_TimeBaseInit( TIM4, &TIM_TimeBaseStructure );

  //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

  //初始化TIM4 Channel4 PWM模式

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

  //选择定时器模式:TIM脉冲宽度调制模式2

  TIM_OCInitStructure.TIM_Pulse = duty_tim4;

  //(TIM_Period)*(duty/100) --> (1000/period)*(duty/100)

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

  //比较输出使能

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  //输出极性:TIM输出比较极性高

  TIM_OC4Init( TIM4, &TIM_OCInitStructure );

  //根据T指定的参数初始化外设TIM4 OC4

  TIM_OC4PreloadConfig( TIM4, TIM_OCPreload_Enable );

  //使能TIM4在CCR4上的预装载寄存器

  TIM_Cmd( TIM4, ENABLE );  //使能TIM4

  TIM_SelectInputTrigger( TIM2, TIM_TS_ITR3 );

  //选择有效输入端 ,查表得知TIM4对于TIM2是ITR3
  TIM_SelectSlaveMode( TIM2, TIM_SlaveMode_Gated );
//配置为主从复位模式

  TIM_SelectOutputTrigger( TIM4, TIM_TRGOSource_OC4Ref );

  /* Enable timer's master/slave work mode */

  TIM_SelectMasterSlaveMode( TIM2, TIM_MasterSlaveMode_Enable );   //Slave

  TIM_SelectMasterSlaveMode( TIM4, TIM_MasterSlaveMode_Enable );   //Master

}

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