USART_LL_EF_Init

Functions
ErrorStatus	LL_USART_DeInit (USART_TypeDef *USARTx)
	De-initialize USART registers (Registers restored to their default values). More...
ErrorStatus	LL_USART_Init (USART_TypeDef *USARTx, LL_USART_InitTypeDef *USART_InitStruct)
	Initialize USART registers according to the specified parameters in USART_InitStruct. More...
void	LL_USART_StructInit (LL_USART_InitTypeDef *USART_InitStruct)
	Set each LL_USART_InitTypeDef field to default value. More...
ErrorStatus	LL_USART_ClockInit (USART_TypeDef *USARTx, LL_USART_ClockInitTypeDef *USART_ClockInitStruct)
	Initialize USART Clock related settings according to the specified parameters in the USART_ClockInitStruct. More...
void	LL_USART_ClockStructInit (LL_USART_ClockInitTypeDef *USART_ClockInitStruct)
	Set each field of a LL_USART_ClockInitTypeDef type structure to default value. More...

Detailed Description

Function Documentation

LL_USART_ClockInit()

ErrorStatus LL_USART_ClockInit	(	USART_TypeDef *	USARTx,
		LL_USART_ClockInitTypeDef *	USART_ClockInitStruct
	)

Initialize USART Clock related settings according to the specified parameters in the USART_ClockInitStruct.

Note

As some bits in USART configuration registers can only be written when the USART is disabled (USART_CR1_UE bit =0), USART Peripheral should be in disabled state prior calling this function. Otherwise, ERROR result will be returned.

Parameters

USARTx	USART Instance
USART_ClockInitStruct	pointer to a LL_USART_ClockInitTypeDef structure that contains the Clock configuration information for the specified USART peripheral.

Return values

An	ErrorStatus enumeration value: SUCCESS: USART registers related to Clock settings are initialized according to USART_ClockInitStruct content ERROR: Problem occurred during USART Registers initialization

Definition at line 375 of file stm32l4xx_ll_usart.c.

{
  ErrorStatus status = SUCCESS;

  /* Check USART Instance and Clock signal output parameters */
  assert_param(IS_UART_INSTANCE(USARTx));
  assert_param(IS_LL_USART_CLOCKOUTPUT(USART_ClockInitStruct->ClockOutput));

  /* USART needs to be in disabled state, in order to be able to configure some bits in
     CRx registers */
  if (LL_USART_IsEnabled(USARTx) == 0U)
  {
    /*---------------------------- USART CR2 Configuration -----------------------*/
    /* If Clock signal has to be output */
    if (USART_ClockInitStruct->ClockOutput == LL_USART_CLOCK_DISABLE)
    {
      /* Deactivate Clock signal delivery :
       * - Disable Clock Output:        USART_CR2_CLKEN cleared
       */
      LL_USART_DisableSCLKOutput(USARTx);
    }
    else
    {
      /* Ensure USART instance is USART capable */
      assert_param(IS_USART_INSTANCE(USARTx));

      /* Check clock related parameters */
      assert_param(IS_LL_USART_CLOCKPOLARITY(USART_ClockInitStruct->ClockPolarity));
      assert_param(IS_LL_USART_CLOCKPHASE(USART_ClockInitStruct->ClockPhase));
      assert_param(IS_LL_USART_LASTBITCLKOUTPUT(USART_ClockInitStruct->LastBitClockPulse));

      /*---------------------------- USART CR2 Configuration -----------------------
       * Configure USARTx CR2 (Clock signal related bits) with parameters:
       * - Enable Clock Output:         USART_CR2_CLKEN set
       * - Clock Polarity:              USART_CR2_CPOL bit according to USART_ClockInitStruct->ClockPolarity value
       * - Clock Phase:                 USART_CR2_CPHA bit according to USART_ClockInitStruct->ClockPhase value
       * - Last Bit Clock Pulse Output: USART_CR2_LBCL bit according to USART_ClockInitStruct->LastBitClockPulse value.
       */
      MODIFY_REG(USARTx->CR2,
                 USART_CR2_CLKEN | USART_CR2_CPHA | USART_CR2_CPOL | USART_CR2_LBCL,
                 USART_CR2_CLKEN | USART_ClockInitStruct->ClockPolarity |
                 USART_ClockInitStruct->ClockPhase | USART_ClockInitStruct->LastBitClockPulse);
    }
  }
  /* Else (USART not in Disabled state => return ERROR */
  else
  {
    status = ERROR;
  }

  return (status);
}

LL_USART_ClockStructInit()

void LL_USART_ClockStructInit

(

LL_USART_ClockInitTypeDef *

USART_ClockInitStruct

)

Set each field of a LL_USART_ClockInitTypeDef type structure to default value.

Parameters

USART_ClockInitStruct

pointer to a LL_USART_ClockInitTypeDef structure whose fields will be set to default values.

Return values

None

Definition at line 434 of file stm32l4xx_ll_usart.c.

{
  /* Set LL_USART_ClockInitStruct fields with default values */
  USART_ClockInitStruct->ClockOutput       = LL_USART_CLOCK_DISABLE;
  USART_ClockInitStruct->ClockPolarity     = LL_USART_POLARITY_LOW;            /* Not relevant when ClockOutput = LL_USART_CLOCK_DISABLE */
  USART_ClockInitStruct->ClockPhase        = LL_USART_PHASE_1EDGE;             /* Not relevant when ClockOutput = LL_USART_CLOCK_DISABLE */
  USART_ClockInitStruct->LastBitClockPulse = LL_USART_LASTCLKPULSE_NO_OUTPUT;  /* Not relevant when ClockOutput = LL_USART_CLOCK_DISABLE */
}

LL_USART_DeInit()

ErrorStatus LL_USART_DeInit

(

USART_TypeDef *

USARTx

)

De-initialize USART registers (Registers restored to their default values).

Parameters

USARTx

USART Instance

Return values

An	ErrorStatus enumeration value: SUCCESS: USART registers are de-initialized ERROR: USART registers are not de-initialized

Definition at line 146 of file stm32l4xx_ll_usart.c.

{
  ErrorStatus status = SUCCESS;

  /* Check the parameters */
  assert_param(IS_UART_INSTANCE(USARTx));

  if (USARTx == USART1)
  {
    /* Force reset of USART clock */
    LL_APB2_GRP1_ForceReset(LL_APB2_GRP1_PERIPH_USART1);

    /* Release reset of USART clock */
    LL_APB2_GRP1_ReleaseReset(LL_APB2_GRP1_PERIPH_USART1);
  }
  else if (USARTx == USART2)
  {
    /* Force reset of USART clock */
    LL_APB1_GRP1_ForceReset(LL_APB1_GRP1_PERIPH_USART2);

    /* Release reset of USART clock */
    LL_APB1_GRP1_ReleaseReset(LL_APB1_GRP1_PERIPH_USART2);
  }
#if defined(USART3)
  else if (USARTx == USART3)
  {
    /* Force reset of USART clock */
    LL_APB1_GRP1_ForceReset(LL_APB1_GRP1_PERIPH_USART3);

    /* Release reset of USART clock */
    LL_APB1_GRP1_ReleaseReset(LL_APB1_GRP1_PERIPH_USART3);
  }
#endif /* USART3 */
#if defined(UART4)
  else if (USARTx == UART4)
  {
    /* Force reset of UART clock */
    LL_APB1_GRP1_ForceReset(LL_APB1_GRP1_PERIPH_UART4);

    /* Release reset of UART clock */
    LL_APB1_GRP1_ReleaseReset(LL_APB1_GRP1_PERIPH_UART4);
  }
#endif /* UART4 */
#if defined(UART5)
  else if (USARTx == UART5)
  {
    /* Force reset of UART clock */
    LL_APB1_GRP1_ForceReset(LL_APB1_GRP1_PERIPH_UART5);

    /* Release reset of UART clock */
    LL_APB1_GRP1_ReleaseReset(LL_APB1_GRP1_PERIPH_UART5);
  }
#endif /* UART5 */
  else
  {
    status = ERROR;
  }

  return (status);
}

LL_USART_Init()

ErrorStatus LL_USART_Init	(	USART_TypeDef *	USARTx,
		LL_USART_InitTypeDef *	USART_InitStruct
	)

Initialize USART registers according to the specified parameters in USART_InitStruct.

Note

As some bits in USART configuration registers can only be written when the USART is disabled (USART_CR1_UE bit =0), USART Peripheral should be in disabled state prior calling this function. Otherwise, ERROR result will be returned.

Baud rate value stored in USART_InitStruct BaudRate field, should be valid (different from 0).

Parameters

USARTx	USART Instance
USART_InitStruct	pointer to a LL_USART_InitTypeDef structure that contains the configuration information for the specified USART peripheral.

Return values

An	ErrorStatus enumeration value: SUCCESS: USART registers are initialized according to USART_InitStruct content ERROR: Problem occurred during USART Registers initialization

Definition at line 220 of file stm32l4xx_ll_usart.c.

{
  ErrorStatus status = ERROR;
  uint32_t periphclk = LL_RCC_PERIPH_FREQUENCY_NO;

  /* Check the parameters */
  assert_param(IS_UART_INSTANCE(USARTx));
#if defined(USART_PRESC_PRESCALER)
  assert_param(IS_LL_USART_PRESCALER(USART_InitStruct->PrescalerValue));
#endif /* USART_PRESC_PRESCALER */
  assert_param(IS_LL_USART_BAUDRATE(USART_InitStruct->BaudRate));
  assert_param(IS_LL_USART_DATAWIDTH(USART_InitStruct->DataWidth));
  assert_param(IS_LL_USART_STOPBITS(USART_InitStruct->StopBits));
  assert_param(IS_LL_USART_PARITY(USART_InitStruct->Parity));
  assert_param(IS_LL_USART_DIRECTION(USART_InitStruct->TransferDirection));
  assert_param(IS_LL_USART_HWCONTROL(USART_InitStruct->HardwareFlowControl));
  assert_param(IS_LL_USART_OVERSAMPLING(USART_InitStruct->OverSampling));

  /* USART needs to be in disabled state, in order to be able to configure some bits in
     CRx registers */
  if (LL_USART_IsEnabled(USARTx) == 0U)
  {
    /*---------------------------- USART CR1 Configuration ---------------------
     * Configure USARTx CR1 (USART Word Length, Parity, Mode and Oversampling bits) with parameters:
     * - DataWidth:          USART_CR1_M bits according to USART_InitStruct->DataWidth value
     * - Parity:             USART_CR1_PCE, USART_CR1_PS bits according to USART_InitStruct->Parity value
     * - TransferDirection:  USART_CR1_TE, USART_CR1_RE bits according to USART_InitStruct->TransferDirection value
     * - Oversampling:       USART_CR1_OVER8 bit according to USART_InitStruct->OverSampling value.
     */
    MODIFY_REG(USARTx->CR1,
               (USART_CR1_M | USART_CR1_PCE | USART_CR1_PS |
                USART_CR1_TE | USART_CR1_RE | USART_CR1_OVER8),
               (USART_InitStruct->DataWidth | USART_InitStruct->Parity |
                USART_InitStruct->TransferDirection | USART_InitStruct->OverSampling));

    /*---------------------------- USART CR2 Configuration ---------------------
     * Configure USARTx CR2 (Stop bits) with parameters:
     * - Stop Bits:          USART_CR2_STOP bits according to USART_InitStruct->StopBits value.
     * - CLKEN, CPOL, CPHA and LBCL bits are to be configured using LL_USART_ClockInit().
     */
    LL_USART_SetStopBitsLength(USARTx, USART_InitStruct->StopBits);

    /*---------------------------- USART CR3 Configuration ---------------------
     * Configure USARTx CR3 (Hardware Flow Control) with parameters:
     * - HardwareFlowControl: USART_CR3_RTSE, USART_CR3_CTSE bits according to USART_InitStruct->HardwareFlowControl value.
     */
    LL_USART_SetHWFlowCtrl(USARTx, USART_InitStruct->HardwareFlowControl);

    /*---------------------------- USART BRR Configuration ---------------------
     * Retrieve Clock frequency used for USART Peripheral
     */
    if (USARTx == USART1)
    {
      periphclk = LL_RCC_GetUSARTClockFreq(LL_RCC_USART1_CLKSOURCE);
    }
    else if (USARTx == USART2)
    {
      periphclk = LL_RCC_GetUSARTClockFreq(LL_RCC_USART2_CLKSOURCE);
    }
#if defined(USART3)
    else if (USARTx == USART3)
    {
      periphclk = LL_RCC_GetUSARTClockFreq(LL_RCC_USART3_CLKSOURCE);
    }
#endif /* USART3 */
#if defined(UART4)
    else if (USARTx == UART4)
    {
      periphclk = LL_RCC_GetUARTClockFreq(LL_RCC_UART4_CLKSOURCE);
    }
#endif /* UART4 */
#if defined(UART5)
    else if (USARTx == UART5)
    {
      periphclk = LL_RCC_GetUARTClockFreq(LL_RCC_UART5_CLKSOURCE);
    }
#endif /* UART5 */
    else
    {
      /* Nothing to do, as error code is already assigned to ERROR value */
    }

    /* Configure the USART Baud Rate :
    #if defined(USART_PRESC_PRESCALER)
       - prescaler value is required
    #endif
       - valid baud rate value (different from 0) is required
       - Peripheral clock as returned by RCC service, should be valid (different from 0).
    */
    if ((periphclk != LL_RCC_PERIPH_FREQUENCY_NO)
        && (USART_InitStruct->BaudRate != 0U))
    {
      status = SUCCESS;
      LL_USART_SetBaudRate(USARTx,
                           periphclk,
#if defined(USART_PRESC_PRESCALER)
                           USART_InitStruct->PrescalerValue,
#endif /* USART_PRESC_PRESCALER */
                           USART_InitStruct->OverSampling,
                           USART_InitStruct->BaudRate);

      /* Check BRR is greater than or equal to 16d */
      assert_param(IS_LL_USART_BRR_MIN(USARTx->BRR));

      /* Check BRR is lower than or equal to 0xFFFF */
      assert_param(IS_LL_USART_BRR_MAX(USARTx->BRR));
    }
#if defined(USART_PRESC_PRESCALER)

    /*---------------------------- USART PRESC Configuration -----------------------
     * Configure USARTx PRESC (Prescaler) with parameters:
     * - PrescalerValue: USART_PRESC_PRESCALER bits according to USART_InitStruct->PrescalerValue value.
     */
    LL_USART_SetPrescaler(USARTx, USART_InitStruct->PrescalerValue);
#endif /* USART_PRESC_PRESCALER */
  }
  /* Endif (=> USART not in Disabled state => return ERROR) */

  return (status);
}

LL_USART_StructInit()

void LL_USART_StructInit

(

LL_USART_InitTypeDef *

USART_InitStruct

)

Set each LL_USART_InitTypeDef field to default value.

Parameters

USART_InitStruct

pointer to a LL_USART_InitTypeDef structure whose fields will be set to default values.

Return values

None

Definition at line 348 of file stm32l4xx_ll_usart.c.

{
  /* Set USART_InitStruct fields to default values */
#if defined(USART_PRESC_PRESCALER)
  USART_InitStruct->PrescalerValue      = LL_USART_PRESCALER_DIV1;
#endif /* USART_PRESC_PRESCALER */
  USART_InitStruct->BaudRate            = 9600U;
  USART_InitStruct->DataWidth           = LL_USART_DATAWIDTH_8B;
  USART_InitStruct->StopBits            = LL_USART_STOPBITS_1;
  USART_InitStruct->Parity              = LL_USART_PARITY_NONE ;
  USART_InitStruct->TransferDirection   = LL_USART_DIRECTION_TX_RX;
  USART_InitStruct->HardwareFlowControl = LL_USART_HWCONTROL_NONE;
  USART_InitStruct->OverSampling        = LL_USART_OVERSAMPLING_16;
}