STM32 2定时器主从模式内部互联，不同步！！有木有解

vari_von 2018-08-26 11:24:34

STM32 2定时器主从模式内部互联，不同步！！有木有解????
实现功能：利用定时器主从模式，通过定时器TIM3 内部输出TIM_TRGOSource_OC1Ref时钟触发TIM2计数，TIM2计数中断关闭TIM3 ,实现TIM3输出PWM脉冲数可控
遇到的问题：TIM3 与 TIM2 开启不同步，TIM3先开启工作一段时间后才输出脉冲触发TIM2计数，原因是什么？求解

/*变量定义*/

//extern ledKeyState  led_key0 ;

uint16_t TIM3per = 500;

int main(void)

{



  vRCC_Config();                            //初始化系统，使得系统频率为72M

Init_Delay(72);



TIM_MasterSlaveModeInit(12,TIM3per,TIM3per>>1);

// TIM_Cmd(TIM2,ENABLE);

// TIM_Cmd(TIM3,ENABLE);



  

  while(1)

  {

//  TIM3per = TIM3per - 2;

//  if(TIM3per < 50)

//   TIM3per = 100;

//  TIM_SetAutoreload(TIM3, TIM3per);//设置TIM3的重装值

//  TIM_SetCompare1(TIM3,TIM3per>>1);//设置占空比为50%

//    TIM_Cmd(TIM3,ENABLE);//使能TIM3;

  }

}



/********************************************************************************

* 函数名：TIM_MasterSlaveModeInit

* 功能  ：设置定时器主从模式 

* 输入  : TIM2per  定时器TIM2重载值

*         TIM3per  定时器TIM3重载值

*         TIM3Compare1  定时器TIM3比较预装载值

* 输出  ：无      

********************************************************************************/



void TIM_MasterSlaveModeInit(uint16_t TIM2per, uint16_t TIM3per, uint16_t TIM3Compare1)

{

  TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;

  TIM_OCInitTypeDef TIM_OCInitStruct;

  GPIO_InitTypeDef GPIO_InitStruct;

NVIC_InitTypeDef NVIC_InitStructure;

  

/*使能外设时钟*/

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE); 

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

  

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

  GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_6;       //PA0

  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA,&GPIO_InitStruct);

  

  /*TIM2工作在单脉冲下*/

  TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;     //没有时钟分割

  TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up; //向上计数模式

  TIM_TimeBaseInitStruct.TIM_Prescaler = 719;                 //预分频值,每100us计数一次

  TIM_TimeBaseInitStruct.TIM_Period = TIM2per;                 //重装值

  TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStruct);

  

//  TIM_SelectOnePulseMode(TIM2,TIM_OPMode_Single);              //设置TIM2在单脉冲模式

  TIM_OC1PreloadConfig(TIM2,TIM_OCPreload_Enable);

  

  

  TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM1;               //在向上计数时

  TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;   //OC1输出使能

  TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_High;       //有效电平为高

  TIM_OCInitStruct.TIM_Pulse = 7;                              //预装载值

  TIM_OC1Init(TIM2,&TIM_OCInitStruct);



/*TIM2中断设置*/

TIM_ClearFlag(TIM2,TIM_FLAG_Update);

  TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);





  NVIC_SetPriorityGrouping(NVIC_PriorityGroup_0);

  NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;  

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; 

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure); 

/*********************/



// TIM_SelectMasterSlaveMode(TIM2,TIM_MasterSlaveMode_Enable);//使能TIM2的主从模式

TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_External1);          //TIM2为上升沿为触发时钟

TIM_SelectInputTrigger(TIM2,TIM_TS_ITR2);                    //内部触发，从TIM3触发





  TIM_ARRPreloadConfig(TIM2, ENABLE);

  TIM_CtrlPWMOutputs(TIM2, ENABLE);

  TIM_Cmd(TIM2,ENABLE);//先不使能能TIM2

  

  

  //TIM3工作在主模式，内部输出脉冲触发TIM2计数

  TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;       //没有时钟分割

  TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;   //向上计数模式

  TIM_TimeBaseInitStruct.TIM_Prescaler = 719;                    //预分频值，1MHz

  TIM_TimeBaseInitStruct.TIM_Period = TIM3per;                   //重装值

  TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStruct);

  

  TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM1;

  TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable; 

  TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_Low; 

  TIM_OCInitStruct.TIM_Pulse = TIM3Compare1; 

  TIM_OC1Init(TIM3,&TIM_OCInitStruct);



  TIM_SelectMasterSlaveMode(TIM3,TIM_MasterSlaveMode_Enable);   //使能TIM3的主从模式

  TIM_SelectOutputTrigger(TIM3,TIM_TRGOSource_OC1Ref);          //输出内部触发



// TIM_OC1PreloadConfig(TIM3,TIM_OCPreload_Disable);

TIM_ARRPreloadConfig(TIM3, ENABLE);

/*使能定时器TIM3主输出*/

  TIM_CtrlPWMOutputs(TIM3, ENABLE);

  

  TIM_Cmd(TIM2,ENABLE);   //使能TIM2

TIM_Cmd(TIM3,ENABLE);   //使能TIM3

}



void TIM2_IRQHandler(void)

{

  if(TIM_GetITStatus(TIM2,TIM_IT_Update)!=RESET)   //检查溢出信号

  {

    TIM_ClearITPendingBit(TIM2,TIM_IT_Update);     //清除溢出标志

    TIM_Cmd(TIM3,DISABLE);

  }

}