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/**
******************************************************************************
* @file I2S/I2S_Audio/Src/audio_if.c
* @author MCD Application Team
* @brief This file provides the Audio Out (playback) interface API
******************************************************************************
* @attention
*
* Copyright (c) 2017 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "audio_if.h"
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private typedef -----------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
static AUDIO_BufferTypeDef buffer_ctl;
static AUDIO_PLAYBACK_StateTypeDef audio_state;
/* Private function prototypes -----------------------------------------------*/
static uint32_t GetData(void *pdata, uint32_t offset, uint8_t *pbuf, uint32_t NbrOfData);
/* Private functions ---------------------------------------------------------*/
/**
* @brief Initializes Audio Interface.
* @param None
* @retval Audio error
*/
AUDIO_ErrorTypeDef AUDIO_Init(void)
{
audio_state = AUDIO_STATE_IDLE;
if(BSP_AUDIO_OUT_Init(OUTPUT_DEVICE_AUTO, AUDIO_DEFAULT_VOLUME, I2S_AUDIOFREQ_8K) == 0)
{
audio_state = AUDIO_STATE_INIT;
return AUDIO_ERROR_NONE;
}
return AUDIO_ERROR_IO;
}
/**
* @brief Starts Audio streaming.
* @param None
* @retval Audio error
*/
AUDIO_ErrorTypeDef AUDIO_Start(void)
{
uint32_t bytesread;
buffer_ctl.state = BUFFER_OFFSET_NONE;
bytesread = GetData( (void *)AUDIO_FILE_ADDRESS,
0,
&buffer_ctl.buff[0],
AUDIO_BUFFER_SIZE);
if(bytesread > 0)
{
BSP_AUDIO_OUT_Play((uint16_t*)&buffer_ctl.buff[0], AUDIO_BUFFER_SIZE);
audio_state = AUDIO_STATE_PLAYING;
buffer_ctl.fptr = bytesread;
return AUDIO_ERROR_NONE;
}
return AUDIO_ERROR_IO;
}
/**
* @brief Manages Audio process.
* @param None
* @retval Audio error
*/
AUDIO_ErrorTypeDef AUDIO_Process(void)
{
uint32_t bytesread;
AUDIO_ErrorTypeDef error_state = AUDIO_ERROR_NONE;
switch(audio_state)
{
case AUDIO_STATE_PLAYING:
if(buffer_ctl.fptr >= AUDIO_FILE_SIZE)
{
/* Play audio sample again ... */
buffer_ctl.fptr = 0;
error_state = AUDIO_ERROR_EOF;
}
/* 1st half buffer played; so fill it and continue playing from bottom*/
if(buffer_ctl.state == BUFFER_OFFSET_HALF)
{
bytesread = GetData((void *)AUDIO_FILE_ADDRESS,
buffer_ctl.fptr,
&buffer_ctl.buff[0],
AUDIO_BUFFER_SIZE /2);
if( bytesread >0)
{
buffer_ctl.state = BUFFER_OFFSET_NONE;
buffer_ctl.fptr += bytesread;
}
}
/* 2nd half buffer played; so fill it and continue playing from top */
if(buffer_ctl.state == BUFFER_OFFSET_FULL)
{
bytesread = GetData((void *)AUDIO_FILE_ADDRESS,
buffer_ctl.fptr,
&buffer_ctl.buff[AUDIO_BUFFER_SIZE /2],
AUDIO_BUFFER_SIZE /2);
if( bytesread > 0)
{
buffer_ctl.state = BUFFER_OFFSET_NONE;
buffer_ctl.fptr += bytesread;
}
}
break;
default:
error_state = AUDIO_ERROR_NOTREADY;
break;
}
return error_state;
}
/**
* @brief Gets Data from storage unit.
* @param None
* @retval None
*/
static uint32_t GetData(void *pdata, uint32_t offset, uint8_t *pbuf, uint32_t NbrOfData)
{
uint8_t *lptr = pdata;
uint32_t ReadDataNbr;
ReadDataNbr = 0;
while(((offset + ReadDataNbr) < AUDIO_FILE_SIZE) && (ReadDataNbr < NbrOfData))
{
pbuf[ReadDataNbr]= lptr [offset + ReadDataNbr];
ReadDataNbr++;
}
return ReadDataNbr;
}
/*------------------------------------------------------------------------------
Callbacks implementation:
the callbacks API are defined __weak in the stm324xg_eval_audio.c file
and their implementation should be done the user code if they are needed.
Below some examples of callback implementations.
----------------------------------------------------------------------------*/
/**
* @brief Calculates the remaining file size and new position of the pointer.
* @param None
* @retval None
*/
void BSP_AUDIO_OUT_TransferComplete_CallBack(void)
{
if(audio_state == AUDIO_STATE_PLAYING)
{
/* Continue Playing from 1st half buffer */
BSP_AUDIO_OUT_ChangeBuffer((uint16_t*)&buffer_ctl.buff[0], AUDIO_BUFFER_SIZE /2);
buffer_ctl.state = BUFFER_OFFSET_FULL;
}
}
/**
* @brief Manages the DMA Half Transfer complete interrupt.
* @param None
* @retval None
*/
void BSP_AUDIO_OUT_HalfTransfer_CallBack(void)
{
if(audio_state == AUDIO_STATE_PLAYING)
{
/* Continue Playing from 2nd half buffer */
BSP_AUDIO_OUT_ChangeBuffer((uint16_t*)&buffer_ctl.buff[AUDIO_BUFFER_SIZE /2], AUDIO_BUFFER_SIZE /2);
buffer_ctl.state = BUFFER_OFFSET_HALF;
}
}
/**
* @brief Manages the DMA FIFO error event.
* @param None
* @retval None
*/
void BSP_AUDIO_OUT_Error_CallBack(void)
{
/* Display message on the LCD screen */
BSP_LCD_SetBackColor(LCD_COLOR_RED);
BSP_LCD_DisplayStringAtLine(8, (uint8_t *)" DMA ERROR ");
/* Stop the program with an infinite loop */
while (1)
{}
/* could also generate a system reset to recover from the error */
/* .... */
}