stm32如何用定时器输出固定数量脉冲

参考程序

#include "stm32f10x.h"
//定时器4主模式
//PWM输出
void TIM4_config(u32 Cycle)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimebaseInitTypeDef  TIM_TimebaseStructure;
    TIM_OCInitTypeDef  TIM_OCInitStructure;
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4 ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;                   //TIM2_CH2 PB7
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;             //复用推挽输出
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB &GPIO_InitStructure);

    TIM_TimebaseStructure.TIM_Period = Cycle-1;                                                   
    TIM_TimebaseStructure.TIM_Prescaler =71;                    //设置用来作为TIMx时钟频率除数的预分频值                                                     
    TIM_TimebaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;     //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);                                       

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;          //选择定时器模式：TIM脉冲宽度调制模式1       
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
    TIM_OCInitStructure.TIM_Pulse = Cycle/2-1;                    //设置待装入捕获寄存器的脉冲值                                   
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;      //输出极性       
    TIM_OC2Init(TIM4 &TIM_OCInitStructure);                                                         

    TIM_SelectMasterSlaveMode(TIM4 TIM_MasterSlaveMode_Enable);
    TIM_SelectOutputTrigger(TIM4 TIM_TRGOSource_Update);

    TIM_OC2PreloadConfig(TIM4 TIM_OCPreload_Enable);                              
    TIM_ARRPreloadConfig(TIM4 ENABLE);                                                          
}
/@@***定时器3从模式***/
void TIM3_config(u32 PulseNum)
{
    TIM_TimebaseInitTypeDef  TIM_TimebaseStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3 ENABLE);

    TIM_TimebaseStructure.TIM_Period = PulseNum-1;   
   TIM_TimebaseStructure.TIM_Prescaler =0;    
    TIM_TimebaseStructure.TIM_ClockDivision = 0;     
    TIM_TimebaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  
    TIM_TimebaseInit(TIM3 &TIM_TimebaseStructure);  

    TIM_SelectInputTrigger(TIM3 TIM_TS_ITR3);
    //TIM_InternalClockConfig(TIM3);
    TIM3->SMCR|=0x07;                                  //设置从模式寄存器
    //TIM_ARRPreloadConfig(TIM3 ENABLE);         
    TIM_ITConfig(TIM3TIM_IT_UpdateDISABLE);

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);
    NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;        
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;     
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}
void Pulse_output(u32 Cycleu32 PulseNum)
{
    TIM3_config(PulseNum);
    TIM_Cmd(TIM3 ENABLE);
    TIM_ClearITPendingBit(TIM3TIM_IT_Update);
    TIM_ITConfig(TIM3TIM_IT_UpdateENABLE);
    TIM4_config(Cycle);
    TIM_Cmd(TIM4 ENABLE);
}