STM32CubeF1

/**
  @page I2S_AUDIO  How to use the Audio features with I2S peripheral
  
  @verbatim
  ******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
  * @file    I2S/I2S_Audio/readme.txt 
  * @author  MCD Application Team
  * @brief   Description of the I2S Audio Example.
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2016 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  @endverbatim

@par Example Description 

Basic implementation of audio features. This example allows playing an audio 
file with an external codec on the STM32F1xx board through the I2S 
peripheral using DMA transfer.

In this example the I2S input clock, provided by a dedicated PLL (PLLI2S),  is
configured to have an audio sampling frequency at 8 KHz with Master clock enabled.

This example uses an audio codec driver which consists of two independent layers:
 - Codec Hardware layer: which controls and communicates with the audio codec 
   (CS43L22) implemented on the evaluation board.
 - The high layer: which implements overall control and interfacing API allowing
   to perform basic audio operations (Init, Play, Pause, Resume, Stop, Volume 
   control and audio file pointer management)

In this example the audio file is stored in the internal flash memory (Mono, 
16-bit, 8 KHz). The analog output device is automatically detected (Speaker or 
Headphone) when the Headphone is plugged/unplugged in/from the audio jack of the 
evaluation board. The example also manages information display and control interface
through push buttons: 
 - When the application is Playing audio file:
     + KEY push button: Pause
     + WAKEUP push button: Volume UP
     + TAMPER: Volume DOWN
 - When the application is Paused:
     + KEY push button: Play
     + WAKEUP push button: Switch output target to Headphone
     + TAMPER: Switch output target to Speaker
This example plays the audio file stored in internal flash memory and replays it
when it reaches end of file. But it can be tailored to used different media storage
devices (SDCard (through SDIO), external Memory (through FSMC) ...) or to play 
in streaming mode (ie. from USB port in device or host mode). In this case, Circular
DMA mode should be preferred (by enabling the define DMA_CIRCULAR in
I2Sx_MspInit() API of stm3210c_eval_audio.c file).  

List of Known Limitations and more detailed user notes are provided in file 
stm3210c_eval_audio.c   (under Drivers\BSP\STM3210C-EVAL RevC)

The provided sample Audio file (stored in internal Flash memory) is extracted from:
  - Title: Partita E major, Gavotte en rondeau  
  - Artist/Composer: J.-S. Bach

@par Directory contents 

  - I2S/I2S_Audio/Inc/stm32f1xx_hal_conf.h    HAL configuration file
  - I2S/I2S_Audio/Inc/stm32f1xx_it.h          Interrupt handlers header file
  - I2S/I2S_Audio/Inc/main.h                  Header for main.c module  
  - I2S/I2S_Audio/Src/stm32f1xx_it.c          Interrupt handlers
  - I2S/I2S_Audio/Src/main.c                  Main program
  - I2S/I2S_Audio/Src/stm32f1xx_hal_msp.c     HAL MSP file
  - I2S/I2S_Audio/Src/system_stm32f1xx.c      STM32F1xx system source file
  - I2S/I2S_Audio/Src/audio_sample.c          Audio Sample file (in tab format)


@par Hardware and Software environment

  - This example runs on STM32F107xC devices.
    
  - This example has been tested with STM3210C-EVAL RevC board and can be
    easily tailored to any other supported device and development board.

  - STM3210C-EVAL RevC Set-up

@par How to use it ? 

 - Use STLink utility, available on www.st.com or any other in system programming
   tool to load a ".wav" file to the STM32 internal flash at the address 0x0800E300.
   Make sure the audio file size does not exceed 512KB. When using STLink utility change
   the audio file extension to "*.bin" in order to be able to load it directly to flash memory.
         @note Audio file present in .\Utilities\Media\AudioFile\ folder
   
In order to make the program work, you must do the following :
 - Open your preferred toolchain
 - Rebuild all files and load your image into target memory
 - Run the example
         @note Make sure that the tool flash loader does not erase or overwrite the
            loaded audio file at address 0x0800E300 by limiting the application
            end address to 0x0803FFFF. This is already done for the example project 
 - Connect a headphone or a speaker to the audio jack connector (CN7).
 * <h3><center>&copy; COPYRIGHT STMicroelectronics</center></h3>
 */