STM32 PWM input mode setting and receiving data using DMA

/****************************************************** *********************
 * Functions
 *************************************************** ************************/

/****************************************************** *********************
 * Interface function: Initialize infrared learning module
 *************************************************** ************************/

void inf_infrared_study_init( void )
{
  // Initialize io port
  inf_init_io( );
  // Initialize interrupt
  //inf_init_irq();
  // Initialize the timer
  inf_init_timer() ;
  
  //Open DMA
  inf_infrared_study_open_dma( 1 );
  //Open the timer
  inf_infrared_study_open_timer( 1 );
}

/****************************************************** *********************
 * Initialize io port
 *************************************************** ************************/

static void inf_init_io(void)
{
  //Define IO initialization structure
  GPIO_InitTypeDef GPIO_InitStructure;
  
  // Initialize the clock
  RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB, ENABLE );
  //Pin initialization  
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
  //Set as input           
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  //initialization         
  GPIO_Init( GPIOA, &GPIO_InitStructure );
}

/****************************************************** *********************
 * Initialization interrupt
 *************************************************** ************************/

static void inf_init_irq(void)
{
  //Define the external interrupt structure
  EXTI_InitTypeDef EXTI_InitStructure;
  
  // Initialize the interrupt pin multiplexing clock
  RCC_APB2PeriphClockCmd( RCC_APB2Periph_AFIO, ENABLE );
  //Configure interrupt source
  GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource1);
  //Configure falling edge trigger
  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 );
}

/****************************************************** *********************
 * Initialize the timer
 *************************************************** ************************/

static void inf_init_timer(void)
{
  //Define the timer structure
  TIM_TimeBaseInitTypeDef timInitStruct;
  // Input capture structure
  TIM_ICInitTypeDef tim_icinit;
  //Define DMA structure
  DMA_InitTypeDef DMA_InitStructure;
  
  //Start DMA clock
  RCC_AHBPeriphClockCmd( RCC_AHBPeriph_DMA1, ENABLE );
  //DMA1 channel configuration
  DMA_DeInit( DMA1_Channel2 );
  //Peripheral address
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) ( &TIM1->CCR1 );
  //Memory address
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t) Rx_Buf_Tim_Dma1;
  //dma transmission direction is one-way
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  //Set the length of the DMA buffer during transmission
  DMA_InitStructure.DMA_BufferSize = RX_LEN_TIM_DMA;
  //Set the DMA peripheral increment mode, a peripheral
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  //Set DMA memory increment mode
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  //Peripheral data word length
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  //Memory data word length
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  //Set DMA transfer mode
  //DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  //Set the DMA priority level
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  //Set the variables in the two DMA memories to access each other
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init( DMA1_Channel2, &DMA_InitStructure );
  
  //Start DMA clock
  RCC_AHBPeriphClockCmd( RCC_AHBPeriph_DMA1, ENABLE );
  //DMA1 channel configuration
  DMA_DeInit( DMA1_Channel3 );
  //Peripheral address
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) ( &TIM1->CCR2 );
  //Memory address
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t) Rx_Buf_Tim_Dma2;
  //dma transmission direction is one-way
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  //Set the length of the DMA buffer during transmission
  DMA_InitStructure.DMA_BufferSize = RX_LEN_TIM_DMA;
  //Set the DMA peripheral increment mode, a peripheral
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  //Set DMA memory increment mode
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  //Peripheral data word length
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  //Memory data word length
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  //Set DMA transfer mode
  //DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  //Set the DMA priority level
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  //Set the variables in the two DMA memories to access each other
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init( DMA1_Channel3, &DMA_InitStructure );
  
  //Start the clock
  RCC_APB2PeriphClockCmd( RCC_APB2Periph_TIM1, ENABLE );
  //Reset the Timer to its default value
  TIM_DeInit( TIM1 );
  //Use the internal clock to provide the clock source
  TIM_InternalClockConfig(TIM1);
  //Pre-scaling
  timInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
  //Counting frequency is 500ns and jumps once      
  timInitStruct.TIM_Prescaler = SystemCoreClock / 1 - 1;
  //Count up          
  timInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
  timInitStruct.TIM_RepetitionCounter = 0;
  //This value is actually TIMX->ARR, and can be reset when the delay starts
  timInitStruct.TIM_Period = 0xffff;
  // Initialize the timer
  TIM_TimeBaseInit(TIM1, &timInitStruct);
  
  // Input capture configuration
  //Select channel
  tim_icinit.TIM_Channel = TIM_Channel_1;
  //Hardware filtering
  tim_icinit.TIM_ICFilter = 0x0;
  //Trigger capture level
  tim_icinit.TIM_ICPolarity = TIM_ICPolarity_Falling;
  //Capture every time a trigger level is detected
  tim_icinit.TIM_ICPrescaler = TIM_ICPSC_DIV1;
  //Channel direction selection
  tim_icinit.TIM_ICSelection = TIM_ICSelection_DirectTI;
  //initialization
  //TIM_ICInit(TIM1,&tim_icinit);
  TIM_PWMIConfig( TIM1, &tim_icinit );
  //Disable ARR preload buffer  
  //TIM_ARRPreloadConfig(TIM1, DISABLE);  
  
  // Input jump selection
  TIM_SelectInputTrigger(TIM1, TIM_TS_TI1FP1);
  //Slave mode: reset mode
  TIM_SelectSlaveMode(TIM1, TIM_SlaveMode_Reset);
  //Master-slave mode selection
  TIM_SelectMasterSlaveMode(TIM1, TIM_MasterSlaveMode_Enable);
  
  //Configure the timer's DMA
  TIM_DMAConfig( TIM1, TIM_DMABase_CCR1, TIM_DMABurstLength_2Bytes );
  //Generate DMA request signal
  TIM_DMACmd(TIM1, TIM_DMA_CC1, ENABLE);
  
  //Configure the timer's DMA
  TIM_DMAConfig( TIM1, TIM_DMABase_CCR2, TIM_DMABurstLength_2Bytes );
  //Generate DMA request signal
  TIM_DMACmd(TIM1, TIM_DMA_CC2, ENABLE);
  
  //Open the timer
  TIM_Cmd( TIM1, ENABLE );
}

/****************************************************** *********************
 * Interface function: open the timer
 *Parameter: state: 0: closed, 1: open
 *************************************************** ************************/

void inf_infrared_study_open_timer( uint8_t state )
{
  if ( state )
  {
    TIM_Cmd( TIM1, ENABLE );
  }
  else
  {
    TIM_Cmd( TIM1, DISABLE );
  }
}

/****************************************************** *********************
 * Interface function: Enable interrupt
 *Parameter: state: 0: closed, 1: open
 *************************************************** ************************/

void inf_infrared_study_open_irq( uint8_t state )
{
  //Define the interrupt structure
  NVIC_InitTypeDef NVIC_InitStructure;
  
  if ( state )
  {
    // Enable interrupt
    NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn; //Channel is set to external interrupt line
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; //Interrupt preemption priority
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; //Interrupt response priority
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //Enable interrupt
    NVIC_Init( &NVIC_InitStructure ); // Initialization
  }
  else
  {
    //Disable interrupts
    NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn; //Channel is set to external interrupt line
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; //Interrupt preemption priority
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; //Interrupt response priority
    NVIC_InitStructure.NVIC_IRQChannelCmd = DISABLE; // Enable interrupt
    NVIC_Init( &NVIC_InitStructure ); // Initialization
  }
}

/****************************************************** *********************
 * Interface function: open DMA
 *Parameter: state: 0: closed, 1: open
 *************************************************** ************************/

void inf_infrared_study_open_dma( uint8_t state )
{
  if ( state )
  {
    //Set the transmission data length
    //DMA_SetCurrDataCounter(DMA1_Channel3,RX_LEN_TIM_DMA);
    //Open DMA
    DMA_Cmd(DMA1_Channel2, ENABLE);
    DMA_Cmd(DMA1_Channel3, ENABLE);
  }
  else
  {
    DMA_Cmd(DMA1_Channel2, DISABLE);
    DMA_Cmd(DMA1_Channel3, ENABLE);
  }
}

/****************************************************** *********************
 * Interface function: Get DMA receive frame length
 * Return: frame length
 *************************************************** ************************/

uint16_t inf_infrared_study_dma_rx_len( void )
{
  //Get the received frame length
  return (RX_LEN_TIM_DMA - DMA_GetCurrDataCounter( DMA1_Channel2 ) );
}