stm32f2xx_usart.c

STM32+Grlib

  assert_param(IS_USART_CPHA(USART_ClockInitStruct->USART_CPHA));
  assert_param(IS_USART_LASTBIT(USART_ClockInitStruct->USART_LastBit));
  
/*---------------------------- USART CR2 Configuration -----------------------*/
  tmpreg = USARTx->CR2;
  /* Clear CLKEN, CPOL, CPHA and LBCL bits */
  tmpreg &= (uint32_t)~((uint32_t)CR2_CLOCK_CLEAR_MASK);
  /* Configure the USART Clock, CPOL, CPHA and LastBit ------------*/
  /* Set CLKEN bit according to USART_Clock value */
  /* Set CPOL bit according to USART_CPOL value */
  /* Set CPHA bit according to USART_CPHA value */
  /* Set LBCL bit according to USART_LastBit value */
  tmpreg |= (uint32_t)USART_ClockInitStruct->USART_Clock | USART_ClockInitStruct->USART_CPOL | 
                 USART_ClockInitStruct->USART_CPHA | USART_ClockInitStruct->USART_LastBit;
  /* Write to USART CR2 */
  USARTx->CR2 = (uint16_t)tmpreg;
}

/**
  * @brief  Fills each USART_ClockInitStruct member with its default value.
  * @param  USART_ClockInitStruct: pointer to a USART_ClockInitTypeDef structure
  *         which will be initialized.
  * @retval None
  */
void USART_ClockStructInit(USART_ClockInitTypeDef* USART_ClockInitStruct)
{
  /* USART_ClockInitStruct members default value */
  USART_ClockInitStruct->USART_Clock = USART_Clock_Disable;
  USART_ClockInitStruct->USART_CPOL = USART_CPOL_Low;
  USART_ClockInitStruct->USART_CPHA = USART_CPHA_1Edge;
  USART_ClockInitStruct->USART_LastBit = USART_LastBit_Disable;
}

/**
  * @brief  Enables or disables the specified USART peripheral.
  * @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 USARTx peripheral.
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_Cmd(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 selected USART by setting the UE bit in the CR1 register */
    USARTx->CR1 |= USART_CR1_UE;
  }
  else
  {
    /* Disable the selected USART by clearing the UE bit in the CR1 register */
    USARTx->CR1 &= (uint16_t)~((uint16_t)USART_CR1_UE);
  }
}

/**
  * @brief  Sets the system clock prescaler.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @param  USART_Prescaler: specifies the prescaler clock. 
  * @note   The function is used for IrDA mode with UART4 and UART5.   
  * @retval None
  */
void USART_SetPrescaler(USART_TypeDef* USARTx, uint8_t USART_Prescaler)
{ 
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  
  /* Clear the USART prescaler */
  USARTx->GTPR &= USART_GTPR_GT;
  /* Set the USART prescaler */
  USARTx->GTPR |= USART_Prescaler;
}

/**
  * @brief  Enables or disables the USART's 8x oversampling mode.
  * @note   This function has to be called before calling USART_Init() function
  *         in order to have correct baudrate Divider value.
  * @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 8x oversampling mode.
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_OverSampling8Cmd(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 8x Oversampling mode by setting the OVER8 bit in the CR1 register */
    USARTx->CR1 |= USART_CR1_OVER8;
  }
  else
  {
    /* Disable the 8x Oversampling mode by clearing the OVER8 bit in the CR1 register */
    USARTx->CR1 &= (uint16_t)~((uint16_t)USART_CR1_OVER8);
  }
}  

/**
  * @brief  Enables or disables the USART's one bit sampling method.
  * @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 one bit sampling method.
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_OneBitMethodCmd(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 one bit method by setting the ONEBITE bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_ONEBIT;
  }
  else
  {
    /* Disable the one bit method by clearing the ONEBITE bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_ONEBIT);
  }
}

/**
  * @}
  */

/** @defgroup USART_Group2 Data transfers functions
 *  @brief   Data transfers functions 
 *
@verbatim   
 ===============================================================================
                            Data transfers functions
 ===============================================================================  

  This subsection provides a set of functions allowing to manage the USART data 
  transfers.
  
  During an USART reception, data shifts in least significant bit first through 
  the RX pin. In this mode, the USART_DR register consists of a buffer (RDR) 
  between the internal bus and the received shift register.

  When a transmission is taking place, a write instruction to the USART_DR register 
  stores the data in the TDR register and which is copied in the shift register 
  at the end of the current transmission.

  The read access of the USART_DR register can be done using the USART_ReceiveData()
  function and returns the RDR buffered value. Whereas a write access to the USART_DR 
  can be done using USART_SendData() function and stores the written data into 
  TDR buffer.

@endverbatim
  * @{
  */

/**
  * @brief  Transmits single data through the USARTx peripheral.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @param  Data: the data to transmit.
  * @retval None
  */
void USART_SendData(USART_TypeDef* USARTx, uint16_t Data)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_DATA(Data)); 
    
  /* Transmit Data */
  USARTx->DR = (Data & (uint16_t)0x01FF);
}

/**
  * @brief  Returns the most recent received data by the USARTx peripheral.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @retval The received data.
  */
uint16_t USART_ReceiveData(USART_TypeDef* USARTx)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  
  /* Receive Data */
  return (uint16_t)(USARTx->DR & (uint16_t)0x01FF);
}

/**
  * @}
  */

/** @defgroup USART_Group3 MultiProcessor Communication functions
 *  @brief   Multi-Processor Communication functions 
 *
@verbatim   
 ===============================================================================
                    Multi-Processor Communication functions
 ===============================================================================  

  This subsection provides a set of functions allowing to manage the USART 
  multiprocessor communication.
  
  For instance one of the USARTs can be the master, its TX output is connected to 
  the RX input of the other USART. The others are slaves, their respective TX outputs 
  are logically ANDed together and connected to the RX input of the master.

  USART multiprocessor communication is possible through the following procedure:
     1. Program the Baud rate, Word length = 9 bits, 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. Configures the wake up method (USART_WakeUp_IdleLine or USART_WakeUp_AddressMark)
        using USART_WakeUpConfig() function only for the slaves.
     4. Enable the USART using the USART_Cmd() function.
     5. Enter the USART slaves in mute mode using USART_ReceiverWakeUpCmd() function.

  The USART Slave exit from mute mode when receive the wake up condition.

@endverbatim
  * @{
  */

/**
  * @brief  Sets the address of the USART node.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @param  USART_Address: Indicates the address of the USART node.
  * @retval None
  */
void USART_SetAddress(USART_TypeDef* USARTx, uint8_t USART_Address)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_ADDRESS(USART_Address)); 
    
  /* Clear the USART address */
  USARTx->CR2 &= (uint16_t)~((uint16_t)USART_CR2_ADD);
  /* Set the USART address node */
  USARTx->CR2 |= USART_Address;
}

/**
  * @brief  Determines if the USART is in mute mode or not.
  * @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 mute mode.
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_ReceiverWakeUpCmd(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 USART mute mode  by setting the RWU bit in the CR1 register */
    USARTx->CR1 |= USART_CR1_RWU;
  }
  else
  {
    /* Disable the USART mute mode by clearing the RWU bit in the CR1 register */
    USARTx->CR1 &= (uint16_t)~((uint16_t)USART_CR1_RWU);
  }
}
/**
  * @brief  Selects the USART WakeUp method.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @param  USART_WakeUp: specifies the USART wakeup method.
  *          This parameter can be one of the following values:
  *            @arg USART_WakeUp_IdleLine: WakeUp by an idle line detection
  *            @arg USART_WakeUp_AddressMark: WakeUp by an address mark
  * @retval None
  */
void USART_WakeUpConfig(USART_TypeDef* USARTx, uint16_t USART_WakeUp)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_WAKEUP(USART_WakeUp));
  
  USARTx->CR1 &= (uint16_t)~((uint16_t)USART_CR1_WAKE);
  USARTx->CR1 |= USART_WakeUp;
}

/**
  * @}
  */

/** @defgroup USART_Group4 LIN mode functions
 *  @brief   LIN mode functions 
 *
@verbatim   
 ===============================================================================
                                LIN mode functions
 ===============================================================================  

  This subsection provides a set of functions allowing to manage the USART LIN 
  Mode communication.
  
  In LIN mode, 8-bit data format with 1 stop bit is required in accordance with 
  the LIN standard.

  Only this LIN Feature is supported by the USART IP:
    - LIN Master Synchronous Break send capability and LIN slave break detection
      capability :  13-bit break generation and 10/11 bit break detection


  USART LIN Master transmitter communication is possible through the following procedure:
     1. Program the Baud rate, Word length = 8bits, Stop bits = 1bit, Parity, 
        Mode transmitter or Mode receiver and hardware flow control values using 
        the USART_Init() function.
     2. Enable the USART using the USART_Cmd() function.
     3. Enable the LIN mode using the USART_LINCmd() function.
     4. Send the break character using USART_SendBreak() function.

  USART LIN Master receiver communication is possible through the following procedure:
     1. Program the Baud rate, Word length = 8bits, Stop bits = 1bit, Parity, 
        Mode transmitter or Mode receiver and hardware flow control values using 
        the USART_Init() function.
     2. Enable the USART using the USART_Cmd() function.
     3. Configures the break detection length using the USART_LINBreakDetectLengthConfig()
        function.
     4. Enable the LIN mode using the USART_LINCmd() function.


@note In LIN mode, the following bits must be kept cleared:
        - CLKEN in the USART_CR2 register,
        - STOP[1:0], SCEN, HDSEL and IREN in the USART_CR3 register.

@endverbatim
  * @{
  */

/**
  * @brief  Sets the USART LIN Break detection length.
  * @param  USARTx: where x can be 1, 2, 3, 4, 5 or 6 to select the USART or 
  *         UART peripheral.
  * @param  USART_LINBreakDetectLength: specifies the LIN break detection length.
  *          This parameter can be one of the following values:
  *            @arg USART_LINBreakDetectLength_10b: 10-bit break detection
  *            @arg USART_LINBreakDetectLength_11b: 11-bit break detection
  * @retval None
  */
void USART_LINBreakDetectLengthConfig(USART_TypeDef* USARTx, uint16_t USART_LINBreakDetectLength)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_LIN_BREAK_DETECT_LENGTH(USART_LINBreakDetectLength));
  
  USARTx->CR2 &= (uint16_t)~((uint16_t)USART_CR2_LBDL);
  USARTx->CR2 |= USART_LINBreakDetectLength;  
}

/**
  * @brief  Enables or disables the USART's LIN mode.