109 lines
4.0 KiB
Plaintext
109 lines
4.0 KiB
Plaintext
Overview
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========
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The maestro_demo application demonstrates audio processing on the ARM cortex core
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utilizing the Maestro Audio Framework library.
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Depending on target platform there are different features of the demo enabled.
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- File decoding and playback
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- EAP effects during file playback
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- Multi-channel playback
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The application is controlled by commands from a shell interface using serial console.
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Type "help" to see the command list. Similar description will be displayed on serial console:
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>> help
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"help": List all the registered commands
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"exit": Exit program
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"version": Display component versions
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"file": Perform audio file decode and playback
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USAGE: file [start|stop|pause|volume|seek|update|set|get|track|list|info]
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start Play default (first found) or specified audio track file.
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stop Stops actual playback.
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pause Pause actual track or resume if already paused.
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volume=<volume> Set volume. The volume can be set from 0 to 100.
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seek=<seek_time> Seek currently paused track. Seek time is absolute time in milliseconds.
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update=<preset> Apply current EAP parameters without attribute value
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or switch to preset 1-10
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set=<preset> Apply current EAP parameters without attribute value
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or switch to preset 1-10
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get Sync actual EAP parameters from library to ATT config structures.
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track=<filename> Select audio track to play.
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list List audio files available on mounted SD card.
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info Prints playback info.
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Toolchain supported
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===================
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- IAR embedded Workbench 9.32.1
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- GCC ARM Embedded 10.3.1
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- MCUXpresso 11.7.0
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Hardware requirements
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=====================
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- Mini/micro USB cable
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- LPCXpresso55s69 board
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- Personal Computer
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- headphones with 3.5 mm stereo jack
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- source of sound (line output to 3.5 mm stereo jack)
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Board settings
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==============
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Insert the card into the card slot
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Prepare the Demo
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================
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Note: MCUXpresso IDE project default debug console is semihost
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1. Connect headphones to Audio HP / Line-Out connector.
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2. Connect source of sound to Audio Line-In connector.
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3. Connect a micro USB cable between the PC host and the CMSIS DAP USB port (P6) on the board
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4. Open a serial terminal with the following settings :
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- 115200 baud rate
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- 8 data bits
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- No parity
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- One stop bit
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- No flow control
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5. Download the program to the target board.
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6. Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
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Note:
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There is limited RAM on this platform, which brings following limitations:
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- EAP is enabled just with mp3 files
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- OPUS decoder is disabled due to insufficient memory
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- To enable AAC decoding and playback it is necessary to disable EAP:
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1. Define AAC_DEC=1 in the project settings
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2. Undefine EAP_PROC in the project settings
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- To enable WAV decoding and playback it is necessary to disable EAP:
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1. Define WAV_DEC=1 in the project settings
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2. Undefine EAP_PROC in the project settings
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- To enable FLAC decoding and playback it is necessary to disable EAP:
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1. Define FLAC_DEC=1 in the project settings
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2. Undefine EAP_PROC in the project settings
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- When playing FLAC audio files with too small frame size (block size), the audio output may be distorted because the board is not fast enough.
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- The AAC decoder is only supported in MCUXpresso and ARMGCC.
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Running the demo
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================
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When the example runs successfully, you should see similar output on the serial terminal as below:
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*********************************
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Maestro audio playback demo start
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*********************************
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[APP_Main_Task] started
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Copyright 2022 NXP
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[APP_SDCARD_Task] start
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[APP_Shell_Task] start
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>> [APP_SDCARD_Task] SD card drive mounted
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Known issues
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1. MP3 decoder has issues with some of the files. One of the channels can be sometimes distorted or missing parts of the signal.
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