stm32f2xx_usart.c

STM32+Grlib

  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @param  NewState: new state of the USART LIN mode.
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_LINCmd(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 LIN mode by setting the LINEN bit in the CR2 register */
    USARTx->CR2 |= USART_CR2_LINEN;
  }
  else
  {
    /* Disable the LIN mode by clearing the LINEN bit in the CR2 register */
    USARTx->CR2 &= (uint16_t)~((uint16_t)USART_CR2_LINEN);
  }
}

/**
  * @brief  Transmits break characters.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @retval None
  */
void USART_SendBreak(USART_TypeDef* USARTx)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  
  /* Send break characters */
  USARTx->CR1 |= USART_CR1_SBK;
}

/**
  * @}
  */

/** @defgroup USART_Group5 Halfduplex mode function
 *  @brief   Half-duplex mode function 
 *
@verbatim   
 ===============================================================================
                         Half-duplex mode function
 ===============================================================================  

  This subsection provides a set of functions allowing to manage the USART 
  Half-duplex communication.
  
  The USART can be configured to follow a single-wire half-duplex protocol where 
  the TX and RX lines are internally connected.

  USART Half duplex communication is possible through the following procedure:
     1. Program the Baud rate, Word length, Stop bits, Parity, Mode transmitter 
        or Mode receiver and hardware flow control values using the USART_Init()
        function.
     2. Configures the USART address using the USART_SetAddress() function.
     3. Enable the USART using the USART_Cmd() function.
     4. Enable the half duplex mode using USART_HalfDuplexCmd() function.


@note The RX pin is no longer used
@note In Half-duplex mode the following bits must be kept cleared:
        - LINEN and CLKEN bits in the USART_CR2 register.
        - SCEN and IREN bits in the USART_CR3 register.

@endverbatim
  * @{
  */

/**
  * @brief  Enables or disables the USART's Half Duplex communication.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @param  NewState: new state of the USART Communication.
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_HalfDuplexCmd(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 Half-Duplex mode by setting the HDSEL bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_HDSEL;
  }
  else
  {
    /* Disable the Half-Duplex mode by clearing the HDSEL bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_HDSEL);
  }
}

/**
  * @}
  */


/** @defgroup USART_Group6 Smartcard mode functions
 *  @brief   Smartcard mode functions 
 *
@verbatim   
 ===============================================================================
                               Smartcard mode functions
 ===============================================================================  

  This subsection provides a set of functions allowing to manage the USART 
  Smartcard communication.
  
  The Smartcard interface is designed to support asynchronous protocol Smartcards as
  defined in the ISO 7816-3 standard.

  The USART can provide a clock to the smartcard through the SCLK output.
  In smartcard mode, SCLK is not associated to the communication but is simply derived 
  from the internal peripheral input clock through a 5-bit prescaler.

  Smartcard communication is possible through the following procedure:
     1. Configures the Smartcard Prescaler using the USART_SetPrescaler() function.
     2. Configures the Smartcard Guard Time using the USART_SetGuardTime() function.
     3. Program the USART clock using the USART_ClockInit() function as following:
        - USART Clock enabled
        - USART CPOL Low
        - USART CPHA on first edge
        - USART Last Bit Clock Enabled
     4. Program the Smartcard interface using the USART_Init() function as following:
        - Word Length = 9 Bits
        - 1.5 Stop Bit
        - Even parity
        - BaudRate = 12096 baud
        - Hardware flow control disabled (RTS and CTS signals)
        - Tx and Rx enabled
     5. Optionally you can enable the parity error interrupt using the USART_ITConfig()
        function
     6. Enable the USART using the USART_Cmd() function.
     7. Enable the Smartcard NACK using the USART_SmartCardNACKCmd() function.
     8. Enable the Smartcard interface using the USART_SmartCardCmd() function.

  Please refer to the ISO 7816-3 specification for more details.


@note It is also possible to choose 0.5 stop bit for receiving but it is recommended 
      to use 1.5 stop bits for both transmitting and receiving to avoid switching 
      between the two configurations.
@note In smartcard mode, the following bits must be kept cleared:
        - LINEN bit in the USART_CR2 register.
        - HDSEL and IREN bits in the USART_CR3 register.
@note Smartcard mode is available on USART peripherals only (not available on UART4 
      and UART5 peripherals).

@endverbatim
  * @{
  */

/**
  * @brief  Sets the specified USART guard time.
  * @param  USARTx: where x can be 1, 2, 3 or 6 to select the USART or 
  *         UART peripheral.
  * @param  USART_GuardTime: specifies the guard time.   
  * @retval None
  */
void USART_SetGuardTime(USART_TypeDef* USARTx, uint8_t USART_GuardTime)
{    
  /* Check the parameters */
  assert_param(IS_USART_1236_PERIPH(USARTx));
  
  /* Clear the USART Guard time */
  USARTx->GTPR &= USART_GTPR_PSC;
  /* Set the USART guard time */
  USARTx->GTPR |= (uint16_t)((uint16_t)USART_GuardTime << 0x08);
}

/**
  * @brief  Enables or disables the USART's Smart Card mode.
  * @param  USARTx: where x can be 1, 2, 3 or 6 to select the USART or 
  *         UART peripheral.
  * @param  NewState: new state of the Smart Card mode.
  *          This parameter can be: ENABLE or DISABLE.      
  * @retval None
  */
void USART_SmartCardCmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_1236_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the SC mode by setting the SCEN bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_SCEN;
  }
  else
  {
    /* Disable the SC mode by clearing the SCEN bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_SCEN);
  }
}

/**
  * @brief  Enables or disables NACK transmission.
  * @param  USARTx: where x can be 1, 2, 3 or 6 to select the USART or 
  *         UART peripheral.
  * @param  NewState: new state of the NACK transmission.
  *          This parameter can be: ENABLE or DISABLE.  
  * @retval None
  */
void USART_SmartCardNACKCmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_1236_PERIPH(USARTx)); 
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the NACK transmission by setting the NACK bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_NACK;
  }
  else
  {
    /* Disable the NACK transmission by clearing the NACK bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_NACK);
  }
}

/**
  * @}
  */

/** @defgroup USART_Group7 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:
     1. Program the Baud rate, Word length = 8 bits, Stop bits, Parity, Transmitter/Receiver 
        modes and hardware flow control values using the USART_Init() function.
     2. Enable the USART using the USART_Cmd() function.
     3. Configures the IrDA pulse width by configuring the prescaler using  
        the USART_SetPrescaler() function.
     4. Configures the IrDA  USART_IrDAMode_LowPower or USART_IrDAMode_Normal mode
        using the USART_IrDAConfig() function.
     5. Enable the IrDA using the USART_IrDACmd() function.

@note A pulse of width less than two and greater than one PSC period(s) may or may
      not be rejected.
@note 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).
@note 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, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART 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, uint16_t USART_IrDAMode)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_IRDA_MODE(USART_IrDAMode));
    
  USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_IRLP);
  USARTx->CR3 |= USART_IrDAMode;
}

/**
  * @brief  Enables or disables the USART's IrDA interface.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART 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_ALL_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 &= (uint16_t)~((uint16_t)USART_CR3_IREN);
  }
}

/**
  * @}
  */

/** @defgroup USART_Group8 DMA transfers management functions
 *  @brief   DMA transfers management functions
 *
@verbatim   
 ===============================================================================
                      DMA transfers management functions
 ===============================================================================  

@endverbatim
  * @{
  */
  
/**
  * @brief  Enables or disables the USART's DMA interface.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART 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, uint16_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 &= (uint16_t)~USART_DMAReq;
  }