stm32主从模式定时器产生精确脉冲个数

STM32的每个定时器都可以由另一个定时器触发启动定时器一般是通过软件设置而启动，STM32的每个定时器也可以通过外部信号触发而启动，还可以通过另外一个定时器的某一个条件被触发而启动.这里所谓某一个条件可以是定时到时、定时器超时、比较成功等许多条件.这种通过一个定时器触发另一个定时器的工作方式称为定时器的同步，发出触发信号的定时器工作于主模式，接受触发信号而启动的定时器工作于从模式。

STM32 的Timer之间可以用Timer Internal Trigger联系起来。

各个Timer之间的联系可以用下表表示



实例：

#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(TIM3,TIM_IT_Update,DISABLE);

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 Cycle,u32 PulseNum)
{
TIM3_config(PulseNum);
TIM_Cmd(TIM3, ENABLE);
TIM_ClearITPendingBit(TIM3,TIM_IT_Update);
TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE);
TIM4_config(Cycle);
TIM_Cmd(TIM4, ENABLE);
}