stm32f4_discovery_audio.c

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/*==============================================================================
                                             User NOTES
1. How To use this driver:
--------------------------
   - This driver supports STM32F4xx devices on STM32F4-Discovery Kit:
        a) to play an audio file (all functions names start by BSP_AUDIO_OUT_xxx)
        b) to record an audio file through MP45DT02, ST MEMS (all functions names start by AUDIO_IN_xxx)
 
a) PLAY A FILE:
==============
   + Call the function BSP_AUDIO_OUT_Init(
                                    OutputDevice: physical output mode (OUTPUT_DEVICE_SPEAKER, 
                                                 OUTPUT_DEVICE_HEADPHONE, OUTPUT_DEVICE_AUTO or 
                                                 OUTPUT_DEVICE_BOTH)
                                    Volume: initial volume to be set (0 is min (mute), 100 is max (100%)
                                    AudioFreq: Audio frequency in Hz (8000, 16000, 22500, 32000 ...)
                                    this parameter is relative to the audio file/stream type.
                                   )
      This function configures all the hardware required for the audio application (codec, I2C, I2S, 
      GPIOs, DMA and interrupt if needed). This function returns 0 if configuration is OK.
      If the returned value is different from 0 or the function is stuck then the communication with
      the codec (try to un-plug the power or reset device in this case).
      - OUTPUT_DEVICE_SPEAKER: only speaker will be set as output for the audio stream.
      - OUTPUT_DEVICE_HEADPHONE: only headphones will be set as output for the audio stream.
      - OUTPUT_DEVICE_AUTO: Selection of output device is made through external switch (implemented 
         into the audio jack on the discovery board). When the Headphone is connected it is used
         as output. When the headphone is disconnected from the audio jack, the output is
         automatically switched to Speaker.
      - OUTPUT_DEVICE_BOTH: both Speaker and Headphone are used as outputs for the audio stream
         at the same time.
   + Call the function BSP_AUDIO_OUT_Play(
                                  pBuffer: pointer to the audio data file address
                                  Size: size of the buffer to be sent in Bytes
                                 )
      to start playing (for the first time) from the audio file/stream.
   + Call the function BSP_AUDIO_OUT_Pause() to pause playing 
   + Call the function BSP_AUDIO_OUT_Resume() to resume playing.
       Note. After calling BSP_AUDIO_OUT_Pause() function for pause, only BSP_AUDIO_OUT_Resume() should be called
          for resume (it is not allowed to call BSP_AUDIO_OUT_Play() in this case).
       Note. This function should be called only when the audio file is played or paused (not stopped).
   + For each mode, you may need to implement the relative callback functions into your code.
      The Callback functions are named BSP_AUDIO_OUT_XXXCallBack() and only their prototypes are declared in 
      the stm32f4_discovery_audio.h file. (refer to the example for more details on the callbacks implementations)
   + To Stop playing, to modify the volume level, the frequency or to mute, use the functions
       BSP_AUDIO_OUT_Stop(), BSP_AUDIO_OUT_SetVolume(), AUDIO_OUT_SetFrequency() BSP_AUDIO_OUT_SetOutputMode and BSP_AUDIO_OUT_SetMute().
   + The driver API and the callback functions are at the end of the stm32f4_discovery_audio.h file.
   
Driver architecture:
--------------------
   + This driver provide the High Audio Layer: consists of the function API exported in the stm32f4_discovery_audio.h file
       (BSP_AUDIO_OUT_Init(), BSP_AUDIO_OUT_Play() ...)
   + This driver provide also the Media Access Layer (MAL): which consists of functions allowing to access the media containing/
       providing the audio file/stream. These functions are also included as local functions into
       the stm32f4_discovery_audio.c file (I2S3_Init()...)
 
Known Limitations:
-------------------
   1- When using the Speaker, if the audio file quality is not high enough, the speaker output
      may produce high and uncomfortable noise level. To avoid this issue, to use speaker
      output properly, try to increase audio file sampling rate (typically higher than 48KHz).
      This operation will lead to larger file size.
   2- Communication with the audio codec (through I2C) may be corrupted if it is interrupted by some
      user interrupt routines (in this case, interrupts could be disabled just before the start of 
      communication then re-enabled when it is over). Note that this communication is only done at
      the configuration phase (BSP_AUDIO_OUT_Init() or BSP_AUDIO_OUT_Stop()) and when Volume control modification is 
      performed (BSP_AUDIO_OUT_SetVolume() or BSP_AUDIO_OUT_SetMute()or BSP_AUDIO_OUT_SetOutputMode()). 
      When the audio data is played, no communication is required with the audio codec.
   3- Parsing of audio file is not implemented (in order to determine audio file properties: Mono/Stereo, Data size, 
      File size, Audio Frequency, Audio Data header size ...). The configuration is fixed for the given audio file.
   4- Supports only Stereo audio streaming. To play mono audio streams, each data should be sent twice 
      on the I2S or should be duplicated on the source buffer. Or convert the stream in stereo before playing.
   5- Supports only 16-bits audio data size.
 
b) RECORD A FILE:
================
   + Call the function BSP_AUDIO_IN_Init(
                                    AudioFreq: Audio frequency in Hz (8000, 16000, 22500, 32000 ...)
                                    )
      This function configures all the hardware required for the audio application (I2S, 
      GPIOs, DMA and interrupt if needed). This function returns 0 if configuration is OK.
 
   + Call the function BSP_AUDIO_IN_Record(
                            pbuf Main buffer pointer for the recorded data storing  
                            size Current size of the recorded buffer
                            )
      to start recording from the microphone.
 
   + User needs to implement user callbacks to retrieve data saved in the record buffer
      (AUDIO_IN_RxHalfCpltCallback/BSP_AUDIO_IN_ReceiveComplete_CallBack)
 
   + Call the function AUDIO_IN_STOP() to stop recording 
 
==============================================================================*/
 
/* Includes ------------------------------------------------------------------*/
#include "stm32f4_discovery_audio.h"
 
/* These PLL parameters are valid when the f(VCO clock) = 1Mhz */
const uint32_t I2SFreq[8] = {8000, 11025, 16000, 22050, 32000, 44100, 48000, 96000};
const uint32_t I2SPLLN[8] = {256, 429, 213, 429, 426, 271, 258, 344};
const uint32_t I2SPLLR[8] = {5, 4, 4, 4, 4, 6, 3, 1};
/*##### PLAY #####*/
static AUDIO_DrvTypeDef           *pAudioDrv;
I2S_HandleTypeDef                 hAudioOutI2s;
 
/*### RECORDER ###*/
I2S_HandleTypeDef                 hAudioInI2s;
 
/* PDM filters params */
PDM_Filter_Handler_t  PDM_FilterHandler[2];
PDM_Filter_Config_t   PDM_FilterConfig[2];
 
__IO uint16_t AudioInVolume = DEFAULT_AUDIO_IN_VOLUME;
static uint8_t I2S3_Init(uint32_t AudioFreq);
static uint8_t I2S2_Init(uint32_t AudioFreq);
static void PDMDecoder_Init(uint32_t AudioFreq, uint32_t ChnlNbrIn, uint32_t ChnlNbrOut);
uint8_t BSP_AUDIO_OUT_Init(uint16_t OutputDevice, uint8_t Volume, uint32_t AudioFreq)
{    
  uint8_t ret = AUDIO_OK;
  
  /* PLL clock is set depending by the AudioFreq (44.1khz vs 48khz groups) */ 
  BSP_AUDIO_OUT_ClockConfig(&hAudioOutI2s, AudioFreq, NULL);
  
  /* I2S data transfer preparation:
  Prepare the Media to be used for the audio transfer from memory to I2S peripheral */
  hAudioOutI2s.Instance = I2S3;
  if(HAL_I2S_GetState(&hAudioOutI2s) == HAL_I2S_STATE_RESET)
  {
    /* Init the I2S MSP: this __weak function can be redefined by the application*/
    BSP_AUDIO_OUT_MspInit(&hAudioOutI2s, NULL);
  }
  
  /* I2S data transfer preparation:
  Prepare the Media to be used for the audio transfer from memory to I2S peripheral */
  /* Configure the I2S peripheral */
  if(I2S3_Init(AudioFreq) != AUDIO_OK)
  {
    ret = AUDIO_ERROR;
  }
  
  if(ret == AUDIO_OK)
  {
    /* Retieve audio codec identifier */
    if(((cs43l22_drv.ReadID(AUDIO_I2C_ADDRESS)) & CS43L22_ID_MASK) == CS43L22_ID)
    {  
      /* Initialize the audio driver structure */
      pAudioDrv = &cs43l22_drv; 
    }
    else
    {
      ret = AUDIO_ERROR;
    }
  }
  
  if(ret == AUDIO_OK)
  {
    pAudioDrv->Init(AUDIO_I2C_ADDRESS, OutputDevice, Volume, AudioFreq);
  }
  
  return ret;
}
 
uint8_t BSP_AUDIO_OUT_Play(uint16_t* pBuffer, uint32_t Size)
{
  /* Call the audio Codec Play function */
  if(pAudioDrv->Play(AUDIO_I2C_ADDRESS, pBuffer, Size) != 0)
  {
    return AUDIO_ERROR;
  }
  else 
  {
    /* Update the Media layer and enable it for play */  
    HAL_I2S_Transmit_DMA(&hAudioOutI2s, pBuffer, DMA_MAX(Size/AUDIODATA_SIZE)); 
    
    /* Return AUDIO_OK when all operations are correctly done */
    return AUDIO_OK;
  }
}
 
void BSP_AUDIO_OUT_ChangeBuffer(uint16_t *pData, uint16_t Size)
{
  HAL_I2S_Transmit_DMA(&hAudioOutI2s, pData, Size); 
}
 
uint8_t BSP_AUDIO_OUT_Pause(void)
{    
  /* Call the Audio Codec Pause/Resume function */
  if(pAudioDrv->Pause(AUDIO_I2C_ADDRESS) != 0)
  {
    return AUDIO_ERROR;
  }
  else
  {
    /* Call the Media layer pause function */
    HAL_I2S_DMAPause(&hAudioOutI2s);
    
    /* Return AUDIO_OK when all operations are correctly done */
    return AUDIO_OK;
  }
}
 
uint8_t BSP_AUDIO_OUT_Resume(void)
{    
  /* Call the Audio Codec Pause/Resume function */
  if(pAudioDrv->Resume(AUDIO_I2C_ADDRESS) != 0)
  {
    return AUDIO_ERROR;
  }
  else
  {
    /* Call the Media layer resume function */
    HAL_I2S_DMAResume(&hAudioOutI2s);
    
    /* Return AUDIO_OK when all operations are correctly done */
    return AUDIO_OK;
  }
}
 
uint8_t BSP_AUDIO_OUT_Stop(uint32_t Option)
{
  /* Call DMA Stop to disable DMA stream before stopping codec */
  HAL_I2S_DMAStop(&hAudioOutI2s);
  
  /* Call Audio Codec Stop function */
  if(pAudioDrv->Stop(AUDIO_I2C_ADDRESS, Option) != 0)
  {
    return AUDIO_ERROR;
  }
  else
  {
    if(Option == CODEC_PDWN_HW)
    { 
      /* Wait at least 1ms */
      HAL_Delay(1);
      
      /* Reset the pin */
      HAL_GPIO_WritePin(AUDIO_RESET_GPIO, AUDIO_RESET_PIN, GPIO_PIN_RESET);
    }
    
    /* Return AUDIO_OK when all operations are correctly done */
    return AUDIO_OK;
  }
}
 
uint8_t BSP_AUDIO_OUT_SetVolume(uint8_t Volume)
{
  /* Call the codec volume control function with converted volume value */
  if(pAudioDrv->SetVolume(AUDIO_I2C_ADDRESS, Volume) != 0)
  {
    return AUDIO_ERROR;
  }
  else
  {
    /* Return AUDIO_OK when all operations are correctly done */
    return AUDIO_OK;
  }
}
 
uint8_t BSP_AUDIO_OUT_SetMute(uint32_t Cmd)
{ 
  /* Call the Codec Mute function */
  if(pAudioDrv->SetMute(AUDIO_I2C_ADDRESS, Cmd) != 0)
  {
    return AUDIO_ERROR;
  }
  else
  {
    /* Return AUDIO_OK when all operations are correctly done */
    return AUDIO_OK;
  }
}
 
uint8_t BSP_AUDIO_OUT_SetOutputMode(uint8_t Output)
{
  /* Call the Codec output Device function */
  if(pAudioDrv->SetOutputMode(AUDIO_I2C_ADDRESS, Output) != 0)
  {
    return AUDIO_ERROR;
  }
  else
  {
    /* Return AUDIO_OK when all operations are correctly done */
    return AUDIO_OK;
  }
}
 
void BSP_AUDIO_OUT_SetFrequency(uint32_t AudioFreq)
{
  /* PLL clock is set depending by the AudioFreq (44.1khz vs 48khz groups) */ 
  BSP_AUDIO_OUT_ClockConfig(&hAudioOutI2s, AudioFreq, NULL);
  
  /* Update the I2S audio frequency configuration */
  I2S3_Init(AudioFreq);
}
 
void HAL_I2S_TxCpltCallback(I2S_HandleTypeDef *hi2s)
{
  if(hi2s->Instance == I2S3)
  {
    /* Call the user function which will manage directly transfer complete */  
    BSP_AUDIO_OUT_TransferComplete_CallBack();       
  }
}
 
void HAL_I2S_TxHalfCpltCallback(I2S_HandleTypeDef *hi2s)
{
  if(hi2s->Instance == I2S3)
  {
    /* Manage the remaining file size and new address offset: This function should
       be coded by user (its prototype is already declared in stm32f4_discovery_audio.h) */  
    BSP_AUDIO_OUT_HalfTransfer_CallBack();
  }
}
 
__weak void BSP_AUDIO_OUT_ClockConfig(I2S_HandleTypeDef *hi2s, uint32_t AudioFreq, void *Params)
{ 
  RCC_PeriphCLKInitTypeDef rccclkinit;
  uint8_t index = 0, freqindex = 0xFF;
  
  for(index = 0; index < 8; index++)
  {
    if(I2SFreq[index] == AudioFreq)
    {
      freqindex = index;
    }
  }
  /* Enable PLLI2S clock */
  HAL_RCCEx_GetPeriphCLKConfig(&rccclkinit);
  /* PLLI2S_VCO Input = HSE_VALUE/PLL_M = 1 Mhz */
  if ((freqindex & 0x7) == 0)
  {
    /* I2S clock config 
    PLLI2S_VCO = f(VCO clock) = f(PLLI2S clock input) × (PLLI2SN/PLLM)
    I2SCLK = f(PLLI2S clock output) = f(VCO clock) / PLLI2SR */
    rccclkinit.PeriphClockSelection = RCC_PERIPHCLK_I2S;
    rccclkinit.PLLI2S.PLLI2SN = I2SPLLN[freqindex];
    rccclkinit.PLLI2S.PLLI2SR = I2SPLLR[freqindex];
    HAL_RCCEx_PeriphCLKConfig(&rccclkinit);
  }
  else 
  {
    /* I2S clock config 
    PLLI2S_VCO = f(VCO clock) = f(PLLI2S clock input) × (PLLI2SN/PLLM)
    I2SCLK = f(PLLI2S clock output) = f(VCO clock) / PLLI2SR */
    rccclkinit.PeriphClockSelection = RCC_PERIPHCLK_I2S;
    rccclkinit.PLLI2S.PLLI2SN = 258;
    rccclkinit.PLLI2S.PLLI2SR = 3;
    HAL_RCCEx_PeriphCLKConfig(&rccclkinit);
  }
}
 
__weak void BSP_AUDIO_OUT_MspInit(I2S_HandleTypeDef *hi2s, void *Params)
{
  static DMA_HandleTypeDef hdma_i2sTx;
  GPIO_InitTypeDef  GPIO_InitStruct;
  
  /* Enable I2S3 clock */
  I2S3_CLK_ENABLE();
  
  /*** Configure the GPIOs ***/  
  /* Enable I2S GPIO clocks */
  I2S3_SCK_SD_CLK_ENABLE();
  I2S3_WS_CLK_ENABLE();
  
  /* I2S3 pins configuration: WS, SCK and SD pins ----------------------------*/
  GPIO_InitStruct.Pin         = I2S3_SCK_PIN | I2S3_SD_PIN; 
  GPIO_InitStruct.Mode        = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull        = GPIO_NOPULL;
  GPIO_InitStruct.Speed       = GPIO_SPEED_FAST;
  GPIO_InitStruct.Alternate   = I2S3_SCK_SD_WS_AF;
  HAL_GPIO_Init(I2S3_SCK_SD_GPIO_PORT, &GPIO_InitStruct);
  
  GPIO_InitStruct.Pin         = I2S3_WS_PIN ;
  HAL_GPIO_Init(I2S3_WS_GPIO_PORT, &GPIO_InitStruct); 
  
  /* I2S3 pins configuration: MCK pin */
  I2S3_MCK_CLK_ENABLE();
  GPIO_InitStruct.Pin         = I2S3_MCK_PIN; 
  HAL_GPIO_Init(I2S3_MCK_GPIO_PORT, &GPIO_InitStruct);   
  
  /* Enable the I2S DMA clock */
  I2S3_DMAx_CLK_ENABLE(); 
  
  if(hi2s->Instance == I2S3)
  {
    /* Configure the hdma_i2sTx handle parameters */   
    hdma_i2sTx.Init.Channel             = I2S3_DMAx_CHANNEL;  
    hdma_i2sTx.Init.Direction           = DMA_MEMORY_TO_PERIPH;
    hdma_i2sTx.Init.PeriphInc           = DMA_PINC_DISABLE;
    hdma_i2sTx.Init.MemInc              = DMA_MINC_ENABLE;
    hdma_i2sTx.Init.PeriphDataAlignment = I2S3_DMAx_PERIPH_DATA_SIZE;
    hdma_i2sTx.Init.MemDataAlignment    = I2S3_DMAx_MEM_DATA_SIZE;
    hdma_i2sTx.Init.Mode                = DMA_NORMAL;
    hdma_i2sTx.Init.Priority            = DMA_PRIORITY_HIGH;
    hdma_i2sTx.Init.FIFOMode            = DMA_FIFOMODE_ENABLE;         
    hdma_i2sTx.Init.FIFOThreshold       = DMA_FIFO_THRESHOLD_FULL;
    hdma_i2sTx.Init.MemBurst            = DMA_MBURST_SINGLE;
    hdma_i2sTx.Init.PeriphBurst         = DMA_PBURST_SINGLE; 
    
    hdma_i2sTx.Instance                 = I2S3_DMAx_STREAM;
    
    /* Associate the DMA handle */
    __HAL_LINKDMA(hi2s, hdmatx, hdma_i2sTx);
    
    /* Deinitialize the Stream for new transfer */
    HAL_DMA_DeInit(&hdma_i2sTx);
    
    /* Configure the DMA Stream */
    HAL_DMA_Init(&hdma_i2sTx);
  }
  
  /* I2S DMA IRQ Channel configuration */
  HAL_NVIC_SetPriority(I2S3_DMAx_IRQ, AUDIO_OUT_IRQ_PREPRIO, 0);
  HAL_NVIC_EnableIRQ(I2S3_DMAx_IRQ); 
}
 
__weak void BSP_AUDIO_OUT_MspDeInit(I2S_HandleTypeDef *hi2s, void *Params)
{  
  GPIO_InitTypeDef  GPIO_InitStruct;
 
  /* I2S DMA IRQ Channel deactivation */
  HAL_NVIC_DisableIRQ(I2S3_DMAx_IRQ); 
  
  if(hi2s->Instance == I2S3)
  {
    /* Deinitialize the Stream for new transfer */
    HAL_DMA_DeInit(hi2s->hdmatx);
  }
 
 /* Disable I2S block */
  __HAL_I2S_DISABLE(hi2s);
 
  /* CODEC_I2S pins configuration: SCK and SD pins */
  GPIO_InitStruct.Pin = I2S3_SCK_PIN | I2S3_SD_PIN;
  HAL_GPIO_DeInit(I2S3_SCK_SD_GPIO_PORT, GPIO_InitStruct.Pin);
  
  /* CODEC_I2S pins configuration: WS pin */
  GPIO_InitStruct.Pin = I2S3_WS_PIN;
  HAL_GPIO_DeInit(I2S3_WS_GPIO_PORT, GPIO_InitStruct.Pin);
  
  /* CODEC_I2S pins configuration: MCK pin */
  GPIO_InitStruct.Pin = I2S3_MCK_PIN;
  HAL_GPIO_DeInit(I2S3_MCK_GPIO_PORT, GPIO_InitStruct.Pin); 
 
  /* Disable I2S clock */
  I2S3_CLK_DISABLE();
 
  /* GPIO pins clock and DMA clock can be shut down in the applic 
     by surcgarging this __weak function */   
}
 
__weak void BSP_AUDIO_OUT_TransferComplete_CallBack(void)
{
}
 
__weak void BSP_AUDIO_OUT_HalfTransfer_CallBack(void)
{
}
 
__weak void BSP_AUDIO_OUT_Error_CallBack(void)
{
}
 
/*******************************************************************************
                            Static Functions
*******************************************************************************/
 
static uint8_t I2S3_Init(uint32_t AudioFreq)
{
  /* Initialize the hAudioOutI2s Instance parameter */
  hAudioOutI2s.Instance         = I2S3;
 
 /* Disable I2S block */
  __HAL_I2S_DISABLE(&hAudioOutI2s);
  
  /* I2S3 peripheral configuration */
  hAudioOutI2s.Init.AudioFreq   = AudioFreq;
  hAudioOutI2s.Init.ClockSource = I2S_CLOCK_PLL;
  hAudioOutI2s.Init.CPOL        = I2S_CPOL_LOW;
  hAudioOutI2s.Init.DataFormat  = I2S_DATAFORMAT_16B;
  hAudioOutI2s.Init.MCLKOutput  = I2S_MCLKOUTPUT_ENABLE;
  hAudioOutI2s.Init.Mode        = I2S_MODE_MASTER_TX;
  hAudioOutI2s.Init.Standard    = I2S_STANDARD;
  /* Initialize the I2S peripheral with the structure above */  
  if(HAL_I2S_Init(&hAudioOutI2s) != HAL_OK)
  {
    return AUDIO_ERROR;
  }
  else
  {
    return AUDIO_OK;
  }
}
  
uint8_t BSP_AUDIO_IN_Init(uint32_t AudioFreq, uint32_t BitRes, uint32_t ChnlNbr)
{
  
  /* Configure PLL clock */ 
  BSP_AUDIO_IN_ClockConfig(&hAudioInI2s, AudioFreq, NULL);
  
  /* Configure the PDM library */
  /* On STM32F4-Discovery a single microphone is mounted, samples are duplicated
     to make stereo audio streams */
  PDMDecoder_Init(AudioFreq, ChnlNbr, 2);
 
  /* Configure the I2S peripheral */
  hAudioInI2s.Instance = I2S2;
  if(HAL_I2S_GetState(&hAudioInI2s) == HAL_I2S_STATE_RESET)
  { 
    /* Initialize the I2S Msp: this __weak function can be rewritten by the application */
    BSP_AUDIO_IN_MspInit(&hAudioInI2s, NULL);
  }
  
  /* Configure the I2S2 */
  I2S2_Init(AudioFreq);
  
  /* Return AUDIO_OK when all operations are correctly done */
  return AUDIO_OK;
}
 
uint8_t BSP_AUDIO_IN_Record(uint16_t* pbuf, uint32_t size)
{
  uint32_t ret = AUDIO_ERROR;
  
  /* Start the process receive DMA */
  HAL_I2S_Receive_DMA(&hAudioInI2s, pbuf, size);
  
  /* Return AUDIO_OK when all operations are correctly done */
  ret = AUDIO_OK;
  
  return ret;
}
 
uint8_t BSP_AUDIO_IN_Stop(void)
{
  uint32_t ret = AUDIO_ERROR;
  
  /* Call the Media layer pause function */
  HAL_I2S_DMAStop(&hAudioInI2s);  
  
  /* Return AUDIO_OK when all operations are correctly done */
  ret = AUDIO_OK;
  
  return ret;
}
 
uint8_t BSP_AUDIO_IN_Pause(void)
{    
  /* Call the Media layer pause function */
  HAL_I2S_DMAPause(&hAudioInI2s);
  
  /* Return AUDIO_OK when all operations are correctly done */
  return AUDIO_OK;
}
 
uint8_t BSP_AUDIO_IN_Resume(void)
{    
  /* Call the Media layer pause/resume function */
  HAL_I2S_DMAResume(&hAudioInI2s);
  
  /* Return AUDIO_OK when all operations are correctly done */
  return AUDIO_OK;
}
 
uint8_t BSP_AUDIO_IN_SetVolume(uint8_t Volume)
{
  /* Set the Global variable AudioInVolume */
  AudioInVolume = Volume; 
  
  /* Return AUDIO_OK when all operations are correctly done */
  return AUDIO_OK;
}
 
uint8_t BSP_AUDIO_IN_PDMToPCM(uint16_t *PDMBuf, uint16_t *PCMBuf)
{
  uint16_t AppPDM[INTERNAL_BUFF_SIZE/2];
  uint32_t index = 0; 
  
  /* PDM Demux */
  for(index = 0; index<INTERNAL_BUFF_SIZE/2; index++)
  {
    AppPDM[index] = HTONS(PDMBuf[index]);
  }
  
  for(index = 0; index < DEFAULT_AUDIO_IN_CHANNEL_NBR; index++)
  {
    /* PDM to PCM filter */
        PDM_Filter((uint8_t*)&AppPDM[index], (uint16_t*)&(PCMBuf[index]), &PDM_FilterHandler[index]);
  }
  /* Duplicate samples since a single microphone in mounted on STM32F4-Discovery */
  for(index = 0; index < PCM_OUT_SIZE; index++)
  {
    PCMBuf[(index<<1)+1] = PCMBuf[index<<1];
  }
  
  /* Return AUDIO_OK when all operations are correctly done */
  return AUDIO_OK; 
}
 
void HAL_I2S_RxCpltCallback(I2S_HandleTypeDef *hi2s)
{
  /* Call the record update function to get the next buffer to fill and its size (size is ignored) */
  BSP_AUDIO_IN_TransferComplete_CallBack();
}
 
void HAL_I2S_RxHalfCpltCallback(I2S_HandleTypeDef *hi2s)
{
  /* Manage the remaining file size and new address offset: This function 
     should be coded by user (its prototype is already declared in stm32f4_discovery_audio.h) */
  BSP_AUDIO_IN_HalfTransfer_CallBack();
}
 
__weak void BSP_AUDIO_IN_ClockConfig(I2S_HandleTypeDef *hi2s, uint32_t AudioFreq, void *Params)
{
  RCC_PeriphCLKInitTypeDef rccclkinit;
 
  /*Enable PLLI2S clock*/
  HAL_RCCEx_GetPeriphCLKConfig(&rccclkinit);
  /* PLLI2S_VCO Input = HSE_VALUE/PLL_M = 1 Mhz */
  if ((AudioFreq & 0x7) == 0)
  {
    /* Audio frequency multiple of 8 (8/16/32/48/96/192)*/
    /* PLLI2S_VCO Output = PLLI2S_VCO Input * PLLI2SN = 192 Mhz */
    /* I2SCLK = PLLI2S_VCO Output/PLLI2SR = 192/6 = 32 Mhz */
    rccclkinit.PeriphClockSelection = RCC_PERIPHCLK_I2S;
    rccclkinit.PLLI2S.PLLI2SN = 192;
    rccclkinit.PLLI2S.PLLI2SR = 6;
    HAL_RCCEx_PeriphCLKConfig(&rccclkinit);
  }
  else
  {
    /* Other Frequency (11.025/22.500/44.100) */
    /* PLLI2S_VCO Output = PLLI2S_VCO Input * PLLI2SN = 290 Mhz */
    /* I2SCLK = PLLI2S_VCO Output/PLLI2SR = 290/2 = 145 Mhz */
    rccclkinit.PeriphClockSelection = RCC_PERIPHCLK_I2S;
    rccclkinit.PLLI2S.PLLI2SN = 290;
    rccclkinit.PLLI2S.PLLI2SR = 2;
    HAL_RCCEx_PeriphCLKConfig(&rccclkinit);
  }
}
 
__weak void BSP_AUDIO_IN_MspInit(I2S_HandleTypeDef *hi2s, void *Params)
{
  static DMA_HandleTypeDef hdma_i2sRx;
  GPIO_InitTypeDef  GPIO_InitStruct;
  
  /* Enable the I2S2 peripheral clock */
  I2S2_CLK_ENABLE();
 
  /* Enable I2S GPIO clocks */
  I2S2_SCK_GPIO_CLK_ENABLE();
  I2S2_MOSI_GPIO_CLK_ENABLE();
  
  /* I2S2 pins configuration: SCK and MOSI pins ------------------------------*/
  GPIO_InitStruct.Mode      = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull      = GPIO_NOPULL;
  GPIO_InitStruct.Speed     = GPIO_SPEED_FAST;
 
  GPIO_InitStruct.Pin       = I2S2_SCK_PIN; 
  GPIO_InitStruct.Alternate = I2S2_SCK_AF;
  HAL_GPIO_Init(I2S2_SCK_GPIO_PORT, &GPIO_InitStruct);
  
  GPIO_InitStruct.Pin       = I2S2_MOSI_PIN ;
  GPIO_InitStruct.Alternate = I2S2_MOSI_AF;
  HAL_GPIO_Init(I2S2_MOSI_GPIO_PORT, &GPIO_InitStruct); 
 
  /* Enable the DMA clock */
  I2S2_DMAx_CLK_ENABLE();
    
  if(hi2s->Instance == I2S2)
  {
    /* Configure the hdma_i2sRx handle parameters */   
    hdma_i2sRx.Init.Channel             = I2S2_DMAx_CHANNEL;
    hdma_i2sRx.Init.Direction           = DMA_PERIPH_TO_MEMORY;
    hdma_i2sRx.Init.PeriphInc           = DMA_PINC_DISABLE;
    hdma_i2sRx.Init.MemInc              = DMA_MINC_ENABLE;
    hdma_i2sRx.Init.PeriphDataAlignment = I2S2_DMAx_PERIPH_DATA_SIZE;
    hdma_i2sRx.Init.MemDataAlignment    = I2S2_DMAx_MEM_DATA_SIZE;
    hdma_i2sRx.Init.Mode                = DMA_CIRCULAR;
    hdma_i2sRx.Init.Priority            = DMA_PRIORITY_HIGH;
    hdma_i2sRx.Init.FIFOMode            = DMA_FIFOMODE_DISABLE;         
    hdma_i2sRx.Init.FIFOThreshold       = DMA_FIFO_THRESHOLD_FULL;
    hdma_i2sRx.Init.MemBurst            = DMA_MBURST_SINGLE;
    hdma_i2sRx.Init.PeriphBurst         = DMA_MBURST_SINGLE; 
    
    hdma_i2sRx.Instance = I2S2_DMAx_STREAM;
    
    /* Associate the DMA handle */
    __HAL_LINKDMA(hi2s, hdmarx, hdma_i2sRx);
    
    /* Deinitialize the Stream for new transfer */
    HAL_DMA_DeInit(&hdma_i2sRx);
    
    /* Configure the DMA Stream */
    HAL_DMA_Init(&hdma_i2sRx);      
  }
  
  /* I2S DMA IRQ Channel configuration */
  HAL_NVIC_SetPriority(I2S2_DMAx_IRQ, AUDIO_IN_IRQ_PREPRIO, 0);
  HAL_NVIC_EnableIRQ(I2S2_DMAx_IRQ); 
}
 
__weak void BSP_AUDIO_IN_MspDeInit(I2S_HandleTypeDef *hi2s, void *Params)
{
  GPIO_InitTypeDef  gpio_init_structure;
 
  /* I2S DMA IRQ Channel deactivation */
  HAL_NVIC_DisableIRQ(I2S2_DMAx_IRQ); 
  
  if(hi2s->Instance == I2S2)
  {
    /* Deinitialize the Stream for new transfer */
    HAL_DMA_DeInit(hi2s->hdmarx);
  }
 
 /* Disable I2S block */
  __HAL_I2S_DISABLE(hi2s);
 
  /* Disable pins: SCK and SD pins */
  gpio_init_structure.Pin = I2S2_SCK_PIN;
  HAL_GPIO_DeInit(I2S2_SCK_GPIO_PORT, gpio_init_structure.Pin);
  gpio_init_structure.Pin = I2S2_MOSI_PIN;
  HAL_GPIO_DeInit(I2S2_MOSI_GPIO_PORT, gpio_init_structure.Pin); 
 
  /* Disable I2S clock */
  I2S2_CLK_DISABLE();
 
  /* GPIO pins clock and DMA clock can be shut down in the applic 
     by surcgarging this __weak function */ 
}
 
__weak void BSP_AUDIO_IN_TransferComplete_CallBack(void)
{
  /* This function should be implemented by the user application.
     It is called into this driver when the current buffer is filled
     to prepare the next buffer pointer and its size. */
}
 
__weak void BSP_AUDIO_IN_HalfTransfer_CallBack(void)
{
  /* This function should be implemented by the user application.
     It is called into this driver when the current buffer is filled
     to prepare the next buffer pointer and its size. */
}
 
__weak void BSP_AUDIO_IN_Error_Callback(void)
{   
  /* This function is called when an Interrupt due to transfer error on or peripheral
     error occurs. */
}
 
/*******************************************************************************
                            Static Functions
*******************************************************************************/
 
static void PDMDecoder_Init(uint32_t AudioFreq, uint32_t ChnlNbrIn, uint32_t ChnlNbrOut)
{
  uint32_t index = 0;
 
  /* Enable CRC peripheral to unlock the PDM library */
  __HAL_RCC_CRC_CLK_ENABLE();
 
  for(index = 0; index < ChnlNbrIn; index++)
  {
    /* Init PDM filters */
    PDM_FilterHandler[index].bit_order  = PDM_FILTER_BIT_ORDER_LSB;
    PDM_FilterHandler[index].endianness = PDM_FILTER_ENDIANNESS_LE;
    PDM_FilterHandler[index].high_pass_tap = 2122358088;
    PDM_FilterHandler[index].out_ptr_channels = ChnlNbrOut;
    PDM_FilterHandler[index].in_ptr_channels  = ChnlNbrIn;
    PDM_Filter_Init((PDM_Filter_Handler_t *)(&PDM_FilterHandler[index]));
 
    /* PDM lib config phase */
    PDM_FilterConfig[index].output_samples_number = AudioFreq/1000;
    PDM_FilterConfig[index].mic_gain = 24;
    PDM_FilterConfig[index].decimation_factor = PDM_FILTER_DEC_FACTOR_64;
    PDM_Filter_setConfig((PDM_Filter_Handler_t *)&PDM_FilterHandler[index], &PDM_FilterConfig[index]);
  }
}
 
static uint8_t I2S2_Init(uint32_t AudioFreq)
{
  /* Initialize the hAudioInI2s Instance parameter */
  hAudioInI2s.Instance          = I2S2;
  
  /* Disable I2S block */
  __HAL_I2S_DISABLE(&hAudioInI2s);
  
  /* I2S2 peripheral configuration */
  hAudioInI2s.Init.AudioFreq    = 2 * AudioFreq;
  hAudioInI2s.Init.ClockSource  = I2S_CLOCK_PLL;
  hAudioInI2s.Init.CPOL         = I2S_CPOL_HIGH;
  hAudioInI2s.Init.DataFormat   = I2S_DATAFORMAT_16B;
  hAudioInI2s.Init.MCLKOutput   = I2S_MCLKOUTPUT_DISABLE;
  hAudioInI2s.Init.Mode         = I2S_MODE_MASTER_RX;
  hAudioInI2s.Init.Standard     = I2S_STANDARD_LSB;
 
  /* Initialize the I2S peripheral with the structure above */  
  if(HAL_I2S_Init(&hAudioInI2s) != HAL_OK)
  {
    return AUDIO_ERROR;
  }
  else
  {
    return AUDIO_OK; 
  }
}  
 
void HAL_I2S_ErrorCallback(I2S_HandleTypeDef *hi2s)
{
  /* Manage the error generated on DMA FIFO: This function 
     should be coded by user (its prototype is already declared in stm32f4_discovery_audio.h) */  
  if(hi2s->Instance == I2S3)
  {
    BSP_AUDIO_OUT_Error_CallBack();
  }
  if(hi2s->Instance == I2S2)
  {
    BSP_AUDIO_IN_Error_Callback();
  }
}
 
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/