stm32f2xx_spi.c

STM32+Grlib

  /* Get the I2SCFGR register value */
  tmpreg = SPIx->I2SCFGR;
  
  /* If the default value has to be written, reinitialize i2sdiv and i2sodd*/
  if(I2S_InitStruct->I2S_AudioFreq == I2S_AudioFreq_Default)
  {
    i2sodd = (uint16_t)0;
    i2sdiv = (uint16_t)2;   
  }
  /* If the requested audio frequency is not the default, compute the prescaler */
  else
  {
    /* Check the frame length (For the Prescaler computing) *******************/
    if(I2S_InitStruct->I2S_DataFormat == I2S_DataFormat_16b)
    {
      /* Packet length is 16 bits */
      packetlength = 1;
    }
    else
    {
      /* Packet length is 32 bits */
      packetlength = 2;
    }

    /* Get I2S source Clock frequency (only in Silicon RevisionB and RevisionY) */
      
    /* If an external I2S clock has to be used, this define should be set  
       in the project configuration or in the stm32f2xx_conf.h file */
  #ifdef I2S_EXTERNAL_CLOCK_VAL     
    /* Set external clock as I2S clock source */
    if ((RCC->CFGR & RCC_CFGR_I2SSRC) == 0)
    {
      RCC->CFGR |= (uint32_t)RCC_CFGR_I2SSRC;
    }
    
    /* Set the I2S clock to the external clock  value */
    i2sclk = I2S_EXTERNAL_CLOCK_VAL;

  #else /* There is no define for External I2S clock source */
    /* Set PLLI2S as I2S clock source */
    if ((RCC->CFGR & RCC_CFGR_I2SSRC) != 0)
    {
      RCC->CFGR &= ~(uint32_t)RCC_CFGR_I2SSRC;
    }    
    
    /* Get the PLLI2SN value */
    plln = (uint32_t)(((RCC->PLLI2SCFGR & RCC_PLLI2SCFGR_PLLI2SN) >> 6) & \
                      (RCC_PLLI2SCFGR_PLLI2SN >> 6));
    
    /* Get the PLLI2SR value */
    pllr = (uint32_t)(((RCC->PLLI2SCFGR & RCC_PLLI2SCFGR_PLLI2SR) >> 28) & \
                      (RCC_PLLI2SCFGR_PLLI2SR >> 28));
    
    /* Get the PLLM value */
    pllm = (uint32_t)(RCC->PLLCFGR & RCC_PLLCFGR_PLLM);      
    
    /* Get the I2S source clock value */
    i2sclk = (uint32_t)(((HSE_VALUE / pllm) * plln) / pllr);
  #endif /* I2S_EXTERNAL_CLOCK_VAL */
    
    /* Compute the Real divider depending on the MCLK output state, with a floating point */
    if(I2S_InitStruct->I2S_MCLKOutput == I2S_MCLKOutput_Enable)
    {
      /* MCLK output is enabled */
      tmp = (uint16_t)(((((i2sclk / 256) * 10) / I2S_InitStruct->I2S_AudioFreq)) + 5);
    }
    else
    {
      /* MCLK output is disabled */
      tmp = (uint16_t)(((((i2sclk / (32 * packetlength)) *10 ) / I2S_InitStruct->I2S_AudioFreq)) + 5);
    }
    
    /* Remove the flatting point */
    tmp = tmp / 10;  
      
    /* Check the parity of the divider */
    i2sodd = (uint16_t)(tmp & (uint16_t)0x0001);
   
    /* Compute the i2sdiv prescaler */
    i2sdiv = (uint16_t)((tmp - i2sodd) / 2);
   
    /* Get the Mask for the Odd bit (SPI_I2SPR[8]) register */
    i2sodd = (uint16_t) (i2sodd << 8);
  }

  /* Test if the divider is 1 or 0 or greater than 0xFF */
  if ((i2sdiv < 2) || (i2sdiv > 0xFF))
  {
    /* Set the default values */
    i2sdiv = 2;
    i2sodd = 0;
  }

  /* Write to SPIx I2SPR register the computed value */
  SPIx->I2SPR = (uint16_t)((uint16_t)i2sdiv | (uint16_t)(i2sodd | (uint16_t)I2S_InitStruct->I2S_MCLKOutput));
 
  /* Configure the I2S with the SPI_InitStruct values */
  tmpreg |= (uint16_t)((uint16_t)SPI_I2SCFGR_I2SMOD | (uint16_t)(I2S_InitStruct->I2S_Mode | \
                  (uint16_t)(I2S_InitStruct->I2S_Standard | (uint16_t)(I2S_InitStruct->I2S_DataFormat | \
                  (uint16_t)I2S_InitStruct->I2S_CPOL))));
 
  /* Write to SPIx I2SCFGR */  
  SPIx->I2SCFGR = tmpreg;
}

/**
  * @brief  Fills each SPI_InitStruct member with its default value.
  * @param  SPI_InitStruct: pointer to a SPI_InitTypeDef structure which will be initialized.
  * @retval None
  */
void SPI_StructInit(SPI_InitTypeDef* SPI_InitStruct)
{
/*--------------- Reset SPI init structure parameters values -----------------*/
  /* Initialize the SPI_Direction member */
  SPI_InitStruct->SPI_Direction = SPI_Direction_2Lines_FullDuplex;
  /* initialize the SPI_Mode member */
  SPI_InitStruct->SPI_Mode = SPI_Mode_Slave;
  /* initialize the SPI_DataSize member */
  SPI_InitStruct->SPI_DataSize = SPI_DataSize_8b;
  /* Initialize the SPI_CPOL member */
  SPI_InitStruct->SPI_CPOL = SPI_CPOL_Low;
  /* Initialize the SPI_CPHA member */
  SPI_InitStruct->SPI_CPHA = SPI_CPHA_1Edge;
  /* Initialize the SPI_NSS member */
  SPI_InitStruct->SPI_NSS = SPI_NSS_Hard;
  /* Initialize the SPI_BaudRatePrescaler member */
  SPI_InitStruct->SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_2;
  /* Initialize the SPI_FirstBit member */
  SPI_InitStruct->SPI_FirstBit = SPI_FirstBit_MSB;
  /* Initialize the SPI_CRCPolynomial member */
  SPI_InitStruct->SPI_CRCPolynomial = 7;
}

/**
  * @brief  Fills each I2S_InitStruct member with its default value.
  * @param  I2S_InitStruct: pointer to a I2S_InitTypeDef structure which will be initialized.
  * @retval None
  */
void I2S_StructInit(I2S_InitTypeDef* I2S_InitStruct)
{
/*--------------- Reset I2S init structure parameters values -----------------*/
  /* Initialize the I2S_Mode member */
  I2S_InitStruct->I2S_Mode = I2S_Mode_SlaveTx;
  
  /* Initialize the I2S_Standard member */
  I2S_InitStruct->I2S_Standard = I2S_Standard_Phillips;
  
  /* Initialize the I2S_DataFormat member */
  I2S_InitStruct->I2S_DataFormat = I2S_DataFormat_16b;
  
  /* Initialize the I2S_MCLKOutput member */
  I2S_InitStruct->I2S_MCLKOutput = I2S_MCLKOutput_Disable;
  
  /* Initialize the I2S_AudioFreq member */
  I2S_InitStruct->I2S_AudioFreq = I2S_AudioFreq_Default;
  
  /* Initialize the I2S_CPOL member */
  I2S_InitStruct->I2S_CPOL = I2S_CPOL_Low;
}

/**
  * @brief  Enables or disables the specified SPI peripheral.
  * @param  SPIx: where x can be 1, 2 or 3 to select the SPI peripheral.
  * @param  NewState: new state of the SPIx peripheral. 
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void SPI_Cmd(SPI_TypeDef* SPIx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_SPI_ALL_PERIPH(SPIx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the selected SPI peripheral */
    SPIx->CR1 |= SPI_CR1_SPE;
  }
  else
  {
    /* Disable the selected SPI peripheral */
    SPIx->CR1 &= (uint16_t)~((uint16_t)SPI_CR1_SPE);
  }
}

/**
  * @brief  Enables or disables the specified SPI peripheral (in I2S mode).
  * @param  SPIx: where x can be 2 or 3 to select the SPI peripheral.
  * @param  NewState: new state of the SPIx peripheral. 
  *         This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void I2S_Cmd(SPI_TypeDef* SPIx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_SPI_23_PERIPH(SPIx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  
  if (NewState != DISABLE)
  {
    /* Enable the selected SPI peripheral (in I2S mode) */
    SPIx->I2SCFGR |= SPI_I2SCFGR_I2SE;
  }
  else
  {
    /* Disable the selected SPI peripheral in I2S mode */
    SPIx->I2SCFGR &= (uint16_t)~((uint16_t)SPI_I2SCFGR_I2SE);
  }
}

/**
  * @brief  Configures the data size for the selected SPI.
  * @param  SPIx: where x can be 1, 2 or 3 to select the SPI peripheral.
  * @param  SPI_DataSize: specifies the SPI data size.
  *          This parameter can be one of the following values:
  *            @arg SPI_DataSize_16b: Set data frame format to 16bit
  *            @arg SPI_DataSize_8b: Set data frame format to 8bit
  * @retval None
  */
void SPI_DataSizeConfig(SPI_TypeDef* SPIx, uint16_t SPI_DataSize)
{
  /* Check the parameters */
  assert_param(IS_SPI_ALL_PERIPH(SPIx));
  assert_param(IS_SPI_DATASIZE(SPI_DataSize));
  /* Clear DFF bit */
  SPIx->CR1 &= (uint16_t)~SPI_DataSize_16b;
  /* Set new DFF bit value */
  SPIx->CR1 |= SPI_DataSize;
}

/**
  * @brief  Selects the data transfer direction in bidirectional mode for the specified SPI.
  * @param  SPIx: where x can be 1, 2 or 3 to select the SPI peripheral.
  * @param  SPI_Direction: specifies the data transfer direction in bidirectional mode. 
  *          This parameter can be one of the following values:
  *            @arg SPI_Direction_Tx: Selects Tx transmission direction
  *            @arg SPI_Direction_Rx: Selects Rx receive direction
  * @retval None
  */
void SPI_BiDirectionalLineConfig(SPI_TypeDef* SPIx, uint16_t SPI_Direction)
{
  /* Check the parameters */
  assert_param(IS_SPI_ALL_PERIPH(SPIx));
  assert_param(IS_SPI_DIRECTION(SPI_Direction));
  if (SPI_Direction == SPI_Direction_Tx)
  {
    /* Set the Tx only mode */
    SPIx->CR1 |= SPI_Direction_Tx;
  }
  else
  {
    /* Set the Rx only mode */
    SPIx->CR1 &= SPI_Direction_Rx;
  }
}

/**
  * @brief  Configures internally by software the NSS pin for the selected SPI.
  * @param  SPIx: where x can be 1, 2 or 3 to select the SPI peripheral.
  * @param  SPI_NSSInternalSoft: specifies the SPI NSS internal state.
  *          This parameter can be one of the following values:
  *            @arg SPI_NSSInternalSoft_Set: Set NSS pin internally
  *            @arg SPI_NSSInternalSoft_Reset: Reset NSS pin internally
  * @retval None
  */
void SPI_NSSInternalSoftwareConfig(SPI_TypeDef* SPIx, uint16_t SPI_NSSInternalSoft)
{
  /* Check the parameters */
  assert_param(IS_SPI_ALL_PERIPH(SPIx));
  assert_param(IS_SPI_NSS_INTERNAL(SPI_NSSInternalSoft));
  if (SPI_NSSInternalSoft != SPI_NSSInternalSoft_Reset)
  {
    /* Set NSS pin internally by software */
    SPIx->CR1 |= SPI_NSSInternalSoft_Set;
  }
  else
  {
    /* Reset NSS pin internally by software */
    SPIx->CR1 &= SPI_NSSInternalSoft_Reset;
  }
}

/**
  * @brief  Enables or disables the SS output for the selected SPI.
  * @param  SPIx: where x can be 1, 2 or 3 to select the SPI peripheral.
  * @param  NewState: new state of the SPIx SS output. 
  *          This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void SPI_SSOutputCmd(SPI_TypeDef* SPIx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_SPI_ALL_PERIPH(SPIx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {