STM32的PWM输入模式设置并用DMA接收数据

参考 ：STM32输入捕获模式设置并用DMA接收数据

PWM input mode

This mode is a particular case of input capture mode.

The procedure is the same except:

 Two ICx signals are mapped on the same TIx input.
 These 2 ICx signals are active on edges with opposite polarity.
 One of the two TIxFP signals is selected as trigger input and the slave mode controller is configured in reset mode.

For example, you can measure the period (in TIMx_CCR1 register) and the duty cycle (in TIMx_CCR2 register)

of the PWM applied on TI1 using the following procedure (depending on CK_INT frequency and prescaler value):

 Select the active input for TIMx_CCR1: write the CC1S bits to 01 in the TIMx_CCMR1 register (TI1 selected).
 Select the active polarity for TI1FP1 (used both for capture in TIMx_CCR1 and counter clear): write the CC1P and CC1NP bits to ‘0’ (active on rising edge).
 Select the active input for TIMx_CCR2: write the CC2S bits to 10 in the TIMx_CCMR1 register (TI1 selected).
 Select the active polarity for TI1FP2 (used for capture in TIMx_CCR2): write the CC2P and CC2NP bits to ‘1’ (active on falling edge).
 Select the valid trigger input: write the TS bits to 101 in the TIMx_SMCR register (TI1FP1 selected).
 Configure the slave mode controller in reset mode: write the SMS bits to 100 in the TIMx_SMCR register.
 Enable the captures: write the CC1E and CC2E bits to ‘1’ in the TIMx_CCER register.

 

 

STM32的PWM输入模式设置并用DMA接收数据

项目中需要进行红外学习,如果采用输入捕获的方式,因为定时器只能捕获上升沿或者下降沿,

所以只能获得周期,而不能得到具体的红外波的高低电平的时间.

所以采用PWM输入的方式进行捕获. 采用的是PA8脚,对应TIM1的通道1.

/*********************************************************************
 *             函数
 **********************************************************************/

/*********************************************************************
 *             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_8;
  //设置为输入           
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  //初始化         
  GPIO_Init( GPIOA, &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通道配置
  DMA_DeInit( DMA1_Channel2 );
  //外设地址
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) ( &TIM1->CCR1 );
  //内存地址
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t) Rx_Buf_Tim_Dma1;
  //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_Channel2, &DMA_InitStructure );
  
  //启动DMA时钟
  RCC_AHBPeriphClockCmd( RCC_AHBPeriph_DMA1, ENABLE );
  //DMA1通道配置
  DMA_DeInit( DMA1_Channel3 );
  //外设地址
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) ( &TIM1->CCR2 );
  //内存地址
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t) Rx_Buf_Tim_Dma2;
  //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_APB2PeriphClockCmd( RCC_APB2Periph_TIM1, ENABLE );
  //重新将Timer设置为缺省值
  TIM_DeInit( TIM1 );
  //采用内部时钟提供时钟源
  TIM_InternalClockConfig( TIM1 );
  //预分频
  timInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
  //计数频率为500ns跳转1次      
  timInitStruct.TIM_Prescaler = SystemCoreClock / 1000000 - 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
  TIM_TimeBaseInit( TIM1, &timInitStruct );
  
  //输入捕获配置
  //选择通道
  tim_icinit.TIM_Channel = TIM_Channel_1;
  //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(TIM1,&tim_icinit);
  TIM_PWMIConfig( TIM1, &tim_icinit );
  //禁止ARR预装载缓冲器  
  //TIM_ARRPreloadConfig(TIM1, DISABLE);  
  
  //输入跳变选择
  TIM_SelectInputTrigger( TIM1, TIM_TS_TI1FP1 );
  //从机模式:复位模式
  TIM_SelectSlaveMode( TIM1, TIM_SlaveMode_Reset );
  //主从模式选择
  TIM_SelectMasterSlaveMode( TIM1, TIM_MasterSlaveMode_Enable );
  
  //配置定时器的DMA
  TIM_DMAConfig( TIM1, TIM_DMABase_CCR1, TIM_DMABurstLength_2Bytes );
  //产生DMA请求信号
  TIM_DMACmd( TIM1, TIM_DMA_CC1, ENABLE );
  
  //配置定时器的DMA
  TIM_DMAConfig( TIM1, TIM_DMABase_CCR2, TIM_DMABurstLength_2Bytes );
  //产生DMA请求信号
  TIM_DMACmd( TIM1, TIM_DMA_CC2, ENABLE );
  
  //打开定时器
  TIM_Cmd( TIM1, 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( TIM1, ENABLE );
  }
  else
  {
    TIM_Cmd( TIM1, 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_Channel2, ENABLE );
    DMA_Cmd( DMA1_Channel3, ENABLE );
  }
  else
  {
    DMA_Cmd( DMA1_Channel2, DISABLE );
    DMA_Cmd( DMA1_Channel3, ENABLE );
  }
}

/*********************************************************************
 *             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_Channel2 ) );
}