stm32f0xx_usart.c

来自「stm32f0固件库」· C语言 代码 · 共 1,641 行 · 第 1/5 页

/** @defgroup USART_Group9 IrDA mode functions
 *  @brief   IrDA mode functions 
 *
@verbatim   
 ===============================================================================
                        ##### IrDA mode functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to manage the USART
         IrDA communication.
    [..] IrDA is a half duplex communication protocol. If the Transmitter is busy, 
         any data on the IrDA receive line will be ignored by the IrDA decoder 
         and if the Receiver is busy, data on the TX from the USART to IrDA will 
         not be encoded by IrDA. While receiving data, transmission should be 
         avoided as the data to be transmitted could be corrupted.
    [..] IrDA communication is possible through the following procedure:
         (#) Program the Baud rate, Word length = 8 bits, Stop bits, Parity, 
             Transmitter/Receiver modes and hardware flow control values using 
             the USART_Init() function.
         (#) Configures the IrDA pulse width by configuring the prescaler using  
             the USART_SetPrescaler() function.
         (#) Configures the IrDA  USART_IrDAMode_LowPower or USART_IrDAMode_Normal 
             mode using the USART_IrDAConfig() function.
         (#) Enable the IrDA using the USART_IrDACmd() function.
         (#) Enable the USART using the USART_Cmd() function.         
    [..]
    (@) A pulse of width less than two and greater than one PSC period(s) may or 
        may not be rejected.
    (@) The receiver set up time should be managed by software. The IrDA physical 
        layer specification specifies a minimum of 10 ms delay between 
        transmission and reception (IrDA is a half duplex protocol).
    (@) In IrDA mode, the following bits must be kept cleared:
        (+@) LINEN, STOP and CLKEN bits in the USART_CR2 register.
        (+@) SCEN and HDSEL bits in the USART_CR3 register.

@endverbatim
  * @{
  */

/**
  * @brief  Configures the USART's IrDA interface.
  * @param  USARTx: where x can be 1 to select the USART peripheral.
  * @param  USART_IrDAMode: specifies the IrDA mode.
  *   This parameter can be one of the following values:
  *     @arg USART_IrDAMode_LowPower
  *     @arg USART_IrDAMode_Normal
  * @retval None
  */
void USART_IrDAConfig(USART_TypeDef* USARTx, uint32_t USART_IrDAMode)
{
  /* Check the parameters */
  assert_param(IS_USART_1_PERIPH(USARTx));
  assert_param(IS_USART_IRDA_MODE(USART_IrDAMode));

  USARTx->CR3 &= (uint32_t)~((uint32_t)USART_CR3_IRLP);
  USARTx->CR3 |= USART_IrDAMode;
}

/**
  * @brief  Enables or disables the USART's IrDA interface.
  * @param  USARTx: where x can be 1 to select the USART peripheral.
  * @param  NewState: new state of the IrDA mode.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_IrDACmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_1_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));

  if (NewState != DISABLE)
  {
    /* Enable the IrDA mode by setting the IREN bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_IREN;
  }
  else
  {
    /* Disable the IrDA mode by clearing the IREN bit in the CR3 register */
    USARTx->CR3 &= (uint32_t)~((uint32_t)USART_CR3_IREN);
  }
}
/**
  * @}
  */

/** @defgroup USART_Group10 RS485 mode function
 *  @brief  RS485 mode function 
 *
@verbatim  
 ===============================================================================
                        ##### RS485 mode functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to manage the USART
         RS485 flow control.
    [..] RS485 flow control (Driver enable feature) handling is possible through
         the following procedure:
         (#) Program the Baud rate, Word length = 8 bits, Stop bits, Parity, 
             Transmitter/Receiver modes and hardware flow control values using 
             the USART_Init() function.
         (#) Enable the Driver Enable using the USART_DECmd() function.
         (#) Configures the Driver Enable polarity using the USART_DEPolarityConfig()
             function.
         (#) Configures the Driver Enable assertion time using USART_SetDEAssertionTime() 
             function and deassertion time using the USART_SetDEDeassertionTime()
             function.    
         (#) Enable the USART using the USART_Cmd() function.
      -@-  
       (+@) The assertion and dessertion times are expressed in sample time units (1/8 or 
            1/16 bit time, depending on the oversampling rate).
       
@endverbatim
  * @{
  */

/**
  * @brief  Enables or disables the USART's DE functionality.
  * @param  USARTx: where x can be 1 or 2 to select the USART peripheral.
  * @param  NewState: new state of the driver enable mode.
  *   This parameter can be: ENABLE or DISABLE.      
  * @retval None
  */
void USART_DECmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the DE functionality by setting the DEM bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_DEM;
  }
  else
  {
    /* Disable the DE functionality by clearing the DEM bit in the CR3 register */
    USARTx->CR3 &= (uint32_t)~((uint32_t)USART_CR3_DEM);
  }
}

/**
  * @brief  Configures the USART's DE polarity
  * @param  USARTx: where x can be 1 or 2 to select the USART peripheral.
  * @param  USART_DEPolarity: specifies the DE polarity.
  *   This parameter can be one of the following values:
  *     @arg USART_DEPolarity_Low
  *     @arg USART_DEPolarity_High
  * @retval None
  */
void USART_DEPolarityConfig(USART_TypeDef* USARTx, uint32_t USART_DEPolarity)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_DE_POLARITY(USART_DEPolarity));

  USARTx->CR3 &= (uint32_t)~((uint32_t)USART_CR3_DEP);
  USARTx->CR3 |= USART_DEPolarity;
}

/**
  * @brief  Sets the specified RS485 DE assertion time
  * @param  USARTx: where x can be 1 or 2 to select the USART peripheral.
  *  @param  USART_AssertionTime: specifies the time between the activation of the DE
  *  signal and the beginning of the start bit
  * @retval None
  */
void USART_SetDEAssertionTime(USART_TypeDef* USARTx, uint32_t USART_DEAssertionTime)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_DE_ASSERTION_DEASSERTION_TIME(USART_DEAssertionTime)); 

  /* Clear the DE assertion time */
  USARTx->CR1 &= (uint32_t)~((uint32_t)USART_CR1_DEAT);
  /* Set the new value for the DE assertion time */
  USARTx->CR1 |=((uint32_t)USART_DEAssertionTime << (uint32_t)0x15);
}

/**
  * @brief  Sets the specified RS485 DE deassertion time
  * @param  USARTx: where x can be 1 or 2 to select the USART peripheral.
  *  @param  USART_DeassertionTime: specifies the time between the middle of the last 
  *   stop bit in a transmitted message and the de-activation of the DE signal
  * @retval None
  */
void USART_SetDEDeassertionTime(USART_TypeDef* USARTx, uint32_t USART_DEDeassertionTime)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_DE_ASSERTION_DEASSERTION_TIME(USART_DEDeassertionTime)); 

  /* Clear the DE deassertion time */
  USARTx->CR1 &= (uint32_t)~((uint32_t)USART_CR1_DEDT);
  /* Set the new value for the DE deassertion time */
  USARTx->CR1 |=((uint32_t)USART_DEDeassertionTime << (uint32_t)0x10);
}

/**
  * @}
  */

/** @defgroup USART_Group11 DMA transfers management functions
 *  @brief   DMA transfers management functions
 *
@verbatim   
 ===============================================================================
               ##### DMA transfers management functions #####
 ===============================================================================
    [..] This section provides two functions that can be used only in DMA mode.
    [..] In DMA Mode, the USART communication can be managed by 2 DMA Channel 
         requests:
         (#) USART_DMAReq_Tx: specifies the Tx buffer DMA transfer request.
         (#) USART_DMAReq_Rx: specifies the Rx buffer DMA transfer request.
    [..] In this Mode it is advised to use the following function:
         (+) void USART_DMACmd(USART_TypeDef* USARTx, uint16_t USART_DMAReq, 
             FunctionalState NewState).
@endverbatim
  * @{
  */

/**
  * @brief  Enables or disables the USART's DMA interface.
  * @param  USARTx: where x can be 1 or 2 to select the USART peripheral.
  * @param  USART_DMAReq: specifies the DMA request.
  *   This parameter can be any combination of the following values:
  *     @arg USART_DMAReq_Tx: USART DMA transmit request
  *     @arg USART_DMAReq_Rx: USART DMA receive request
  * @param  NewState: new state of the DMA Request sources.
  *   This parameter can be: ENABLE or DISABLE.  
  * @retval None
  */
void USART_DMACmd(USART_TypeDef* USARTx, uint32_t USART_DMAReq, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_DMAREQ(USART_DMAReq));  
  assert_param(IS_FUNCTIONAL_STATE(NewState)); 

  if (NewState != DISABLE)
  {
    /* Enable the DMA transfer for selected requests by setting the DMAT and/or
       DMAR bits in the USART CR3 register */
    USARTx->CR3 |= USART_DMAReq;
  }
  else
  {
    /* Disable the DMA transfer for selected requests by clearing the DMAT and/or
       DMAR bits in the USART CR3 register */
    USARTx->CR3 &= (uint32_t)~USART_DMAReq;
  }
}

/**
  * @brief  Enables or disables the USART's DMA interface when reception error occurs.
  * @param  USARTx: where x can be 1 or 2 to select the USART peripheral.
  * @param  USART_DMAOnError: specifies the DMA status in case of reception error.
  *   This parameter can be any combination of the following values:
  *     @arg USART_DMAOnError_Enable: DMA receive request enabled when the USART DMA  
  *          reception error is asserted.
  *     @arg USART_DMAOnError_Disable: DMA receive request disabled when the USART DMA 
  *          reception error is asserted.
  * @retval None
  */
void USART_DMAReceptionErrorConfig(USART_TypeDef* USARTx, uint32_t USART_DMAOnError)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_DMAONERROR(USART_DMAOnError)); 
  
  /* Clear the DMA Reception error detection bit */
  USARTx->CR3 &= (uint32_t)~((uint32_t)USART_CR3_DDRE);
  /* Set the new value for the DMA Reception error detection bit */
  USARTx->CR3 |= USART_DMAOnError;
}

/**
  * @}
  */
  
/** @defgroup USART_Group12 Interrupts and flags management functions
 *  @brief   Interrupts and flags management functions 
 *
@verbatim   
 ===============================================================================
            ##### Interrupts and flags management functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to configure the 
         USART Interrupts sources, Requests and check or clear the flags or pending bits status. 
         The user should identify which mode will be used in his application to 
         manage the communication: Polling mode, Interrupt mode.

 *** Polling Mode ***
 ====================
    [..] In Polling Mode, the SPI communication can be managed by these flags:
         (#) USART_FLAG_REACK: to indicate the status of the Receive Enable 
             acknowledge flag
         (#) USART_FLAG_TEACK: to indicate the status of the Transmit Enable 
             acknowledge flag.
         (#) USART_FLAG_WUF: to indicate the status of the Wake up flag.
         (#) USART_FLAG_RWU: to indicate the status of the Receive Wake up flag.
         (#) USART_FLAG_SBK: to indicate the status of the Send Break flag.
         (#) USART_FLAG_CMF: to indicate the status of the Character match flag.
         (#) USART_FLAG_BUSY: to indicate the status of the Busy flag.
         (#) USART_FLAG_ABRF: to indicate the status of the Auto baud rate flag.
         (#) USART_FLAG_ABRE: to indicate the status of the Auto baud rate error flag.
         (#) USART_FLAG_EOBF: to indicate the status of the End of block flag.
         (#) USART_FLAG_RTOF: to indicate the status of the Receive time out flag.
         (#) USART_FLAG_nCTSS: to indicate the status of the Inverted nCTS input 
             bit status.
         (#) USART_FLAG_TXE: to indicate the status of the transmit buffer register.
         (#) USART_FLAG_RXNE: to indicate the status of the receive buffer register.
         (#) USART_FLAG_TC: to indicate the status of the transmit operation.
         (#) USART_FLAG_IDLE: to indicate the status of the Idle Line.
         (#) USART_FLAG_CTS: to indicate the status of the nCTS input.
         (#) USART_FLAG_LBD: to indicate the status of the LIN break detection.
         (#) USART_FLAG_NE: to indicate if a noise error occur.
         (#) USART_FLAG_FE: to indicate if a frame error occur.
         (#) USART_FLAG_PE: to indicate if a parity error occur.
         (#) USART_FLAG_ORE: to indicate if an Overrun error occur.
    [..] In this Mode it is advised to use the following functions:
         (+) FlagStatus USART_GetFlagStatus(USART_TypeDef* USARTx, uint16_t USART_FLAG).
         (+) void USART_ClearFlag(USART_TypeDef* USARTx, uint16_t USART_FLAG).

 *** Interrupt Mode ***
 ======================
    [..] In Interrupt Mod