waveplayer.c

st公司的开发板的资料

}

/*******************************************************************************
* Function Name  : Decrement_WaveDataLength
* Description    : Decrements the played wave data length.
* Input          : None
* Output         : WaveDataLength: decrement the played wave data length.
* Return         : Current value of  WaveDataLength variable.
*******************************************************************************/
u32 Decrement_WaveDataLength(void)
{
  if (WaveDataLength != 0x00)
  {
    WaveDataLength--;
  }

  return (WaveDataLength);
}

/*******************************************************************************
* Function Name  : Set_WaveDataLength
* Description    : Decrements the played wave data length.
* Input          : None
* Output         : WaveDataLength: decrement the played wave data length.
* Return         : Current value of  WaveDataLength variable.
*******************************************************************************/
void Set_WaveDataLength(u32 value)
{
  WaveDataLength = value;
}

/*******************************************************************************
* Function Name  : WavePlayer_WaveParsing
* Description    : Checks the format of the .WAV file and gets information about
*                  the audio format. This is done by reading the value of a
*                  number of parameters stored in the file header and comparing
*                  these to the values expected authenticates the format of a
*                  standard .WAV  file (44 bytes will be read). If  it is a valid
*                  .WAV file format, it continues reading the header to determine
*                  the  audio format such as the sample rate and the sampled data
*                  size. If the audio format is supported by this application,
*                  it retrieves the audio format in WAVE_Format structure and
*                  returns a zero value. Otherwise the function fails and the
*                  return value is nonzero.In this case, the return value specifies
*                  the cause of  the function fails. The error codes that can be
*                  returned by this function are declared in the header file.
* Input          : None
* Output         : None
* Return         : Zero value if the function succeed, otherwise it return
*                  a nonzero value which specifies the error code.
*******************************************************************************/
static ErrorCode WavePlayer_WaveParsing(u32 ReadAddress)
{
  u32 index = 0;
  u32 Temp = 0x00;
  u32 ExtraFormatBytes = 0;

  /* Start a read data byte sequence from the Flash starting from @ReadAddress */
  SPI_FLASH_StartReadSequence(ReadAddress);
    
  /* Read chunkID, must be 'RIFF'  ----------------------------------------------*/
  Temp = ReadUnit(4, BigEndian);
  if(Temp != ChunkID)
  {
    return(Unvalid_RIFF_ID);
  }
    
  /* Read the file length ----------------------------------------------------*/
  WAVE_Format.RIFFchunksize = ReadUnit(4, LittleEndian);
  
  /* Read the file format, must be 'WAVE' ------------------------------------*/
  Temp = ReadUnit(4, BigEndian);
  if(Temp != FileFormat)
  {
    return(Unvalid_WAVE_Format);
  }
  
/* Read the format chunk, must be'fmt ' --------------------------------------*/
  Temp = ReadUnit(4, BigEndian);
  if(Temp != FormatID)
  {
    return(Unvalid_FormatChunk_ID);
  }

  /* Read the length of the 'fmt' data, must be 0x10 -------------------------*/
  Temp = ReadUnit(4, LittleEndian);
  if(Temp != 0x10)
  {
    ExtraFormatBytes = 1;
  }

  /* Read the audio format, must be 0x01 (PCM) -------------------------------*/
  WAVE_Format.FormatTag = ReadUnit(2, LittleEndian);
  if(WAVE_Format.FormatTag != WAVE_FORMAT_PCM)
  {
    return(Unsupporetd_FormatTag);
  }
  
  /* Read the number of channels, must be 0x01 (Mono) ------------------------*/
  WAVE_Format.NumChannels = ReadUnit(2, LittleEndian);
  if(WAVE_Format.NumChannels != Channel_Mono)
  {
    return(Unsupporetd_Number_Of_Channel);
  }
  
  /* Read the Sample Rate ----------------------------------------------------*/
  WAVE_Format.SampleRate = ReadUnit(4, LittleEndian);

  /* Update the OCA value according to the .WAV file Sample Rate */
  switch(WAVE_Format.SampleRate)
  {
    case SampleRate_8000 : TIM2ARRValue = 9000; break; /* 8KHz = 72MHz / 9000 */
    case SampleRate_11025: TIM2ARRValue = 6531; break; /* 11.025KHz = 72MHz / 6531 */
    case SampleRate_22050: TIM2ARRValue = 3265; break; /* 22.05KHz = 72MHz / 3265 */  
    case SampleRate_44100: TIM2ARRValue = 1633; break; /* 44.1KHz = 72MHz / 1633 */    
    default: return(Unsupporetd_Sample_Rate);
  }
  
  /* Read the Byte Rate ------------------------------------------------------*/
  WAVE_Format.ByteRate = ReadUnit(4, LittleEndian);
  
  /* Read the block alignment ------------------------------------------------*/
  WAVE_Format.BlockAlign = ReadUnit(2, LittleEndian);
  
  /* Read the number of bits per sample --------------------------------------*/
  WAVE_Format.BitsPerSample = ReadUnit(2, LittleEndian);
  if(WAVE_Format.BitsPerSample != Bits_Per_Sample_8)
  {
    return(Unsupporetd_Bits_Per_Sample);  
  }

  SpeechDataOffset = 36;

/* If there is Extra format bytes, these bytes will be defined in "Fact Chunk" */
  if(ExtraFormatBytes == 1)
  {
    /* Read th Extra format bytes, must be 0x00 ------------------------------*/
    Temp = ReadUnit(2, LittleEndian);
    if(Temp != 0x00)
    {
      return(Unsupporetd_ExtraFormatBytes);
    }

    /* Read the Fact chunk, must be 'fact' -----------------------------------*/
    Temp = ReadUnit(4, BigEndian);
    if(Temp != FactID)
    {
      return(Unvalid_FactChunk_ID);
    }

    /* Read Fact chunk data Size ---------------------------------------------*/
    Temp = ReadUnit(4, LittleEndian);
    
  SpeechDataOffset += 10 + Temp;

    /* Increment SPI Flash read address by Temp bytes by reading Temp dummy bytes */
    for(index = 0; index < Temp; index++)
    {
      SPI_FLASH_SendByte(Dummy_Byte);
    }
  }

/* Read the Data chunk, must be 'data' ---------------------------------------*/
  Temp = ReadUnit(4, BigEndian);

  if(Temp != DataID)
  {
    return(Unvalid_DataChunk_ID);
  }
    
  /* Read the number of sample data ------------------------------------------*/
  WAVE_Format.DataSize = ReadUnit(4, LittleEndian);

  SpeechDataOffset += 8;

  return(Valid_WAVE_File);
}

/*******************************************************************************
* Function Name  : ReadUnit
* Description    : Reads a number of bytes from the SPI Flash and reorder them
*                  in Big or little endian.
* Input          : - NbrOfBytes : number of bytes to read.
*                    This parameter must be a number between 1 and 4.
*                  - ReadAddr : external memory address to read from.
*                  - Endians : specifies the bytes endianness.
*                    This parameter can be one of the following values:
*                          - LittleEndian
*                          - BigEndian
* Output         : None
* Return         : Bytes read from the SPI Flash.
*******************************************************************************/
static u32 ReadUnit(u8 NbrOfBytes, Endianness BytesFormat)
{
  u32 index = 0;
  u32 Temp = 0;

  for(index = 0; index < NbrOfBytes; index++)
  {
    Temp |= SPI_FLASH_ReadByte() << (index * 8);
  }

  if (BytesFormat == BigEndian)
  {
     Temp = __REV_Word(Temp);
  }

  return Temp;
}

/******************* (C) COPYRIGHT 2007 STMicroelectronics *****END OF FILE****/