STM32输入捕获模式设置并用DMA接收数据

本文博客链接:,作者:jdh,转载请注明.

环境：

主机:WIN7

开发环境:MDK4.72

MCU:STM32F103

说明：

项目中需要进行红外学习,于是采用输入捕获取得电平变化时间.并将数据放在DMA中.这样可以避免频繁中断消耗CPU资源.

采用的是PB1脚,对应TIM3的通道4.

源代码:

/**********************************************************************       接口函数:初始化红外学习模块**********************************************************************/void inf_infrared_study_init(void){    //初始化io口   inf_init_io();    //初始化中断    //inf_init_irq();    //初始化定时器    inf_init_timer();        //打开DMA    inf_infrared_study_open_dma(1);    //打开定时器    inf_infrared_study_open_timer(1);}/**********************************************************************       初始化io口**********************************************************************/static void inf_init_io(void){ //定义IO初始化结构体 GPIO_InitTypeDef GPIO_InitStructure; //初始化时钟 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE); //管脚初始化      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1; //设置为输入            GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;  //初始化           GPIO_Init(GPIOB, &GPIO_InitStructure);     }/**********************************************************************       初始化中断**********************************************************************/static void inf_init_irq(void){ //定义外部中断结构体 EXTI_InitTypeDef EXTI_InitStructure; //初始化中断脚复用时钟 RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE); //配置中断源 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB,GPIO_PinSource1); // 配置下降沿触发 EXTI_ClearITPendingBit(EXTI_Line1); EXTI_InitStructure.EXTI_Line = EXTI_Line1; EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; EXTI_InitStructure.EXTI_LineCmd = ENABLE; EXTI_Init(&EXTI_InitStructure);}/**********************************************************************       初始化定时器**********************************************************************/static void inf_init_timer(void){ //定义定时器结构体 TIM_TimeBaseInitTypeDef timInitStruct;    //输入捕获结构体    TIM_ICInitTypeDef tim_icinit; //定义DMA结构体 DMA_InitTypeDef DMA_InitStructure;   //启动DMA时钟    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); //DMA1通道3配置 DMA_DeInit(DMA1_Channel3); //外设地址 DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)(&TIM3->CCR4); //内存地址 DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)Rx_Buf_Tim_Dma; //dma传输方向单向 DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC; //设置DMA在传输时缓冲区的长度 DMA_InitStructure.DMA_BufferSize = RX_LEN_TIM_DMA; //设置DMA的外设递增模式，一个外设 DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //设置DMA的内存递增模式 DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //外设数据字长 DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord; //内存数据字长 DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord; //设置DMA的传输模式 //DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;    DMA_InitStructure.DMA_Mode = DMA_Mode_Circular; //设置DMA的优先级别 DMA_InitStructure.DMA_Priority = DMA_Priority_High; //设置DMA的2个memory中的变量互相访问 DMA_InitStructure.DMA_M2M = DMA_M2M_Disable; DMA_Init(DMA1_Channel3,&DMA_InitStructure);               //开启时钟 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE); //重新将Timer设置为缺省值 TIM_DeInit(TIM3); //采用内部时钟给TIM3提供时钟源 TIM_InternalClockConfig(TIM3); //预分频    timInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;        //计数频率为500ns跳转1次     timInitStruct.TIM_Prescaler = SystemCoreClock / 2000000 - 1;      //向上计数          timInitStruct.TIM_CounterMode = TIM_CounterMode_Up;      timInitStruct.TIM_RepetitionCounter = 0; //这个值实际上就是TIMX->ARR，延时开始时重新设定即可     timInitStruct.TIM_Period = 0xffff;          //初始化定时器3 TIM_TimeBaseInit(TIM3, &timInitStruct);        //输入捕获配置    //选择通道    tim_icinit.TIM_Channel = TIM_Channel_4;    //硬件滤波 tim_icinit.TIM_ICFilter = 0x0;    //触发捕获的电平    tim_icinit.TIM_ICPolarity = TIM_ICPolarity_Falling;    //每次检测到触发电平都捕获 tim_icinit.TIM_ICPrescaler= TIM_ICPSC_DIV1;    //通道方向选择 tim_icinit.TIM_ICSelection = TIM_ICSelection_DirectTI;    //初始化    TIM_ICInit(TIM3,&tim_icinit);     //禁止ARR预装载缓冲器   TIM_ARRPreloadConfig(TIM3, DISABLE);      //输入跳变选择    TIM_SelectInputTrigger(TIM3, TIM_TS_TI2FP2);    //从机模式:复位模式    TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Reset);    //主从模式选择    TIM_SelectMasterSlaveMode(TIM3, TIM_MasterSlaveMode_Enable);     //配置定时器的DMA    TIM_DMAConfig(TIM3,TIM_DMABase_CCR4,TIM_DMABurstLength_2Bytes);    //产生DMA请求信号    TIM_DMACmd(TIM3, TIM_DMA_CC4, ENABLE);    //打开定时器    TIM_Cmd(TIM3, ENABLE);}/**********************************************************************       接口函数:打开定时器*参数:state:状态:0:关闭,1:打开**********************************************************************/void inf_infrared_study_open_timer(uint8_t state){    if (state)    {        TIM_Cmd(TIM3, ENABLE);    }    else    {        TIM_Cmd(TIM3, DISABLE);    }}/**********************************************************************       接口函数:打开中断*参数:state:状态:0:关闭,1:打开**********************************************************************/void inf_infrared_study_open_irq(uint8_t state){    //定义中断结构体 NVIC_InitTypeDef NVIC_InitStructure ;        if (state)    {        //打开中断        NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;    //通道设置为外部中断线        NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;   //中断抢占先等级        NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;            //中断响应优先级        NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;             //打开中断        NVIC_Init(&NVIC_InitStructure);                                 //初始化    }    else    {        //关闭中断        NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;    //通道设置为外部中断线        NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;   //中断抢占先等级        NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;            //中断响应优先级        NVIC_InitStructure.NVIC_IRQChannelCmd = DISABLE;             //打开中断        NVIC_Init(&NVIC_InitStructure);                                 //初始化    }}/**********************************************************************       接口函数:打开DMA*参数:state:状态:0:关闭,1:打开**********************************************************************/void inf_infrared_study_open_dma(uint8_t state){    if (state)    {        //设置传输数据长度  //DMA_SetCurrDataCounter(DMA1_Channel3,RX_LEN_TIM_DMA);     //打开DMA  DMA_Cmd(DMA1_Channel3,ENABLE);    }    else    {        DMA_Cmd(DMA1_Channel3,DISABLE);    }}/**********************************************************************       接口函数:得到DMA接收帧长*返回:帧长**********************************************************************/uint16_t inf_infrared_study_dma_rx_len(void){    //获得接收帧帧长 return (RX_LEN_TIM_DMA - DMA_GetCurrDataCounter(DMA1_Channel3));}

注意：

除TIM6和TIM7之外的定时器都只能采用上升沿或者下降沿捕捉而不能采用双边沿捕捉.

#define  TIM_ICPolarity_Rising             ((uint16_t)0x0000)#define  TIM_ICPolarity_Falling            ((uint16_t)0x0002)#define  TIM_ICPolarity_BothEdge           ((uint16_t)0x000A)#define IS_TIM_IC_POLARITY(POLARITY) (((POLARITY) == TIM_ICPolarity_Rising) || \                                      ((POLARITY) == TIM_ICPolarity_Falling))#define IS_TIM_IC_POLARITY_LITE(POLARITY) (((POLARITY) == TIM_ICPolarity_Rising) || \                                           ((POLARITY) == TIM_ICPolarity_Falling)|| \                                           ((POLARITY) == TIM_ICPolarity_BothEdge))