131 lines
6.1 KiB
Plaintext
131 lines
6.1 KiB
Plaintext
/**
|
|
@page I2S_AUDIO I2S Audio example
|
|
|
|
@verbatim
|
|
******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
|
|
* @file I2S/I2S_Audio/Readme.txt
|
|
* @author MCD Application Team
|
|
* @brief Description of the I2S Audio example.
|
|
******************************************************************************
|
|
* @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.
|
|
*
|
|
******************************************************************************
|
|
@endverbatim
|
|
|
|
@par Example Description
|
|
|
|
Basic implementation of audio features. This example allows playing an audio
|
|
file with an external codec on the STM322xG_EVAL 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 48 KHz with Master clock enabled.
|
|
|
|
This example uses an audio codec driver which consists of three independent layers:
|
|
- Codec Hardware layer: which controls and communicates with the audio codec
|
|
(CS43L22) implemented on the evaluation board.
|
|
- MAL (Media Access Layer): which controls and interfaces with storage media
|
|
storing or providing the audio file/stream.
|
|
- 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 (Stereo,
|
|
16-bit, 48 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 : Pause
|
|
+ Tamper: Volume UP
|
|
+ Wakeup: Volume DOWN
|
|
- When the application is Paused:
|
|
+ Key : Play
|
|
+ Tamper: Switch output target to Headphone
|
|
+ Wakeup: Switch output target to Speaker
|
|
|
|
This example plays the audio file stored in internal Flash memory and replay it
|
|
when it reach 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 AUDIO_MAL_MODE_CIRCULAR in
|
|
stm322xg_eval_audio.h file).
|
|
|
|
List of Known Limitations and more detailed user notes are provided in file
|
|
stm322xg_eval_audio.c (under Drivers/BSP/STM322xG_EVAL)
|
|
|
|
The provided sample audio file, under "/Utilities/Media/Audio/audio_sample_wav.bin"
|
|
that must be stored in internal Flash memory, is extracted from:
|
|
- Title: artofgardens-instr
|
|
- Artist/Composer: Dan O'Connor
|
|
- Creative Commons license: Attribution 3.0 United States
|
|
Please read the license following this link:
|
|
http://creativecommons.org/licenses/by/3.0/us/
|
|
|
|
@note 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.
|
|
|
|
@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
|
|
based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
|
|
a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
|
|
than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
|
|
To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
|
|
|
|
@note The application needs to ensure that the SysTick time base is always set to 1 millisecond
|
|
to have correct HAL operation.
|
|
|
|
|
|
@par Directory contents
|
|
|
|
- I2S/I2S_Audio/Inc/stm32f2xx_hal_conf.h HAL configuration file
|
|
- I2S/I2S_Audio/Inc/stm32f2xx_it.h Interrupt handlers header file
|
|
- I2S/I2S_Audio/Inc/main.h Main program header file
|
|
- I2S/I2S_Audio/Src/audio_if.h Audio Out (playback) interface API header file
|
|
- I2S/I2S_Audio/Src/stm32f2xx_it.c Interrupt handlers
|
|
- I2S/I2S_Audio/Src/main.c Main program
|
|
- I2S/I2S_Audio/Src/system_stm32f2xx.c STM32F2xx system clock configuration file
|
|
- I2S/I2S_Audio/Src/stm32f2xx_hal_msp.c HAL MSP module
|
|
- I2S/I2S_Audio/Src/audio_if.c Audio Out (playback) interface API file
|
|
|
|
|
|
@par Hardware and Software environment
|
|
|
|
- This example runs on STM32F207xx/217xx device.
|
|
|
|
- This example has been tested with STMicroelectronics STM322xG-EVAL
|
|
evaluation boards and can be easily tailored to any other supported device
|
|
and development board.
|
|
|
|
- STM322xG-EVAL Set-up
|
|
- Please ensure that the jumper JP16 is in the position 2-3.
|
|
|
|
|
|
@par How to use it ?
|
|
|
|
- Use STLink utility, available on www.st.com or any other in system programming
|
|
tool to load "/Utilities/Media/Audio/audio_sample_wav.bin" file to the STM32
|
|
internal flash at the address 0x08080000.
|
|
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.
|
|
|
|
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 0x08080000 by limiting the application
|
|
end address to 0x0807FFFF. This is already done for the example project
|
|
- Connect a headphone or a speaker to the audio jack connector (CN11).
|
|
|
|
|
|
*/
|
|
|