这几天在调试STM32407的定时器扩展功能，顺便研究了下利用定时器完成PWM波比较输出以及输入捕获事件，
捕获输入波形的高电平时间，具体代码如下，供参考学习，如有问题，请留言随时沟通!main函数部分代码如下：
#include "sys.h"
#include "delay.h"
#include "usart.h"
#include "led.h"
#include "timer.h"extern u8   TIM2CH3_CAPTURE_STA;        //输入捕获状态,0-1:代表上升沿检测事件发生；1-2：代表下降沿事件发生，下降沿事件发生后，强制清零；
extern u32  TIM2CH3_CAPTURE_VAL1;           //输入捕获值(TIM2是32位)
extern u32  TIM2CH3_CAPTURE_OVERCNT;        //定时器溢出次数计数(TIM2/TIM2是32位),溢出强制输入捕获结束，并赋值高电平为0XFFFFFFFFint main(void)
{ long long temp=0;  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);  //设置系统中断优先级分组2delay_init(168);                                //初始化延时函数uart_init(115200);                                //初始化串口波特率为115200TIM5_CH4_PWM_Init(500-1,84-1);                 //84M/84=1Mhz的计数频率计数到500,PWM频率为1M/500=2Khz     TIM2_CH3_Cap_Init(0XFFFFFFFF,84-1);                 //以1Mhz的频率计数 TIM_SetCompare4(TIM5,150-1);  while(1){   if(TIM2CH3_CAPTURE_STA & 0X02)             //成功捕获到了一次高电平{temp  = TIM2CH3_CAPTURE_VAL1; temp += TIM2CH3_CAPTURE_OVERCNT*0XFFFFFFFF;printf("HIGH LEVEL:%lld usrn",temp); //打印总的高点平时间TIM2CH3_CAPTURE_STA  = 0;               //初始化捕获事件参数，开启下一次捕获TIM2CH3_CAPTURE_VAL1 = 0;            temp = 0;TIM2CH3_CAPTURE_OVERCNT = 0;}}
}定时器输出PWM和输入捕获事件及定时器中断部分代码如下：
#include "timer.h"
#include "led.h"
#include "usart.h"
void TIM5_CH4_PWM_Init(u32 arr,u32 psc)
{                            //此部分需手动修改IO口设置GPIO_InitTypeDef GPIO_InitStructure;TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;TIM_OCInitTypeDef  TIM_OCInitStructure;RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5,ENABLE);   //TIM2时钟使能    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);     //使能PORTA时钟 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3; //GPIOB3GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//复用功能GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;   //速度100MHzGPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化PA3GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_TIM5); //GPIOA3复用位定时器5TIM_TimeBaseStructure.TIM_Prescaler=psc;  //定时器分频TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式TIM_TimeBaseStructure.TIM_Period=arr;   //自动重装载值TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; TIM_TimeBaseInit(TIM5,&TIM_TimeBaseStructure);//初始化TIM5 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2TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性:TIM输出比较极性高TIM_OCInitStructure.TIM_Pulse=0;TIM_OC4Init(TIM5, &TIM_OCInitStructure);  //根据T指定的参数初始化外设TIM5 OC4TIM_OC4PreloadConfig(TIM5, TIM_OCPreload_Enable);  //使能TIM5在CCR4上的预装载寄存器TIM_ARRPreloadConfig(TIM5,ENABLE);TIM_Cmd(TIM5, ENABLE);  //使能TIM5        }  TIM_ICInitTypeDef  TIM2_ICInitStructure;//定时器2通道3输入捕获配置
//arr：自动重装值(TIM2是32位的!!)
//psc：时钟预分频数
void TIM2_CH3_Cap_Init(u32 arr,u16 psc)
{GPIO_InitTypeDef GPIO_InitStructure;TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;NVIC_InitTypeDef NVIC_InitStructure;RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);     //TIM2时钟使能    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);     //使能PORTB时钟 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; //GPIOB10GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//复用功能GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //速度100MHzGPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN; //下拉GPIO_Init(GPIOB,&GPIO_InitStructure); //初始化PB0GPIO_PinAFConfig(GPIOB,GPIO_PinSource10,GPIO_AF_TIM2); //PB10复用位定时器2TIM_TimeBaseStructure.TIM_Prescaler=psc;  //定时器分频TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式TIM_TimeBaseStructure.TIM_Period=arr;   //自动重装载值TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1; TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);//初始化TIM2输入捕获参数TIM2_ICInitStructure.TIM_Channel = TIM_Channel_3;   //TIM2_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;  //上升沿捕获TIM2_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //映射到TI1上TIM2_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;    //配置输入分频,不分频 TIM2_ICInitStructure.TIM_ICFilter = 0x00;//IC3F=0000 配置输入滤波器 不滤波TIM_ICInit(TIM2, &TIM2_ICInitStructure);TIM_ITConfig(TIM2,TIM_IT_Update|TIM_IT_CC3,ENABLE);//允许更新中断 ,允许CC3IE捕获中断    TIM_Cmd(TIM2,ENABLE );  //使能定时器2NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;//抢占优先级2NVIC_InitStructure.NVIC_IRQChannelSubPriority =0;      //子优先级0NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;         //IRQ通道使能NVIC_Init(&NVIC_InitStructure);    //根据指定的参数初始化VIC寄存器、}
//捕获事件状态定义
u8  TIM2CH3_CAPTURE_STA=0;         //输入捕获状态,0-1:代表上升沿检测事件发生；1-2：代表下降沿事件发生，下降沿事件发生后，强制清零；
u32 TIM2CH3_CAPTURE_VAL1 = 0;      //输入捕获值(TIM2是32位)
u32 TIM2CH3_CAPTURE_OVERCNT = 0;   //定时器溢出次数计数(TIM2/TIM2是32位),溢出强制输入捕获结束，并赋值高电平为0XFFFFFFFF//定时器2中断服务程序
void TIM2_IRQHandler(void)
{           if(TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET)//定时器2捕获3通道发生捕获事件{   TIM_Cmd(TIM2,DISABLE );          //首先停止定时器计数，避免造成输入捕获值检测误差if( TIM2CH3_CAPTURE_STA == 0)      //0-1：代表上升沿检测事件发生{// TIM_Cmd(TIM2,DISABLE );TIM_SetCounter(TIM2,0);TIM2CH3_CAPTURE_STA = 1;TIM2CH3_CAPTURE_VAL1 = 0;TIM_OC3PolarityConfig(TIM2,TIM_ICPolarity_Falling);TIM_Cmd(TIM2,ENABLE );}else if( TIM2CH3_CAPTURE_STA == 1)   //1-2：代表下降沿事件发生，捕获事件结束{//  TIM_Cmd(TIM2,DISABLE );TIM2CH3_CAPTURE_VAL1 = TIM_GetCapture3(TIM2);TIM2CH3_CAPTURE_STA = 2;TIM_OC3PolarityConfig(TIM2,TIM_ICPolarity_Rising);TIM_Cmd(TIM2,ENABLE );}}//考虑到输入捕获脉冲较宽，定时器会产生溢出，定义TIM2CH3_CAPTURE_OVERCNT对定时器溢出事件进行统计if(TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)//定时器2发生计数更新事件     {if(TIM2CH3_CAPTURE_OVERCNT >= 0xFFFFFFFF)   //当溢出次数超过OXFFFFFFFF时，强制输入捕获事件结束{TIM2CH3_CAPTURE_OVERCNT &= 0;TIM2CH3_CAPTURE_STA = 2;TIM2CH3_CAPTURE_VAL1 = 0XFFFFFFFF;}else TIM2CH3_CAPTURE_OVERCNT = TIM2CH3_CAPTURE_OVERCNT +1;TIM_ClearITPendingBit(TIM2, TIM_IT_Update);//清除定时器更新中断标志位}TIM_ClearITPendingBit(TIM2, TIM_IT_CC3); //清除捕获中断标志位
}