776c0cab9a
Migrate all Nordic boards to leverage the full extent of zephyr:board directives. Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>
46 lines
1.6 KiB
ReStructuredText
46 lines
1.6 KiB
ReStructuredText
.. zephyr:code-sample:: uac2-implicit-feedback
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:name: USB Audio asynchronous implicit feedback sample
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:relevant-api: usbd_api uac2_device i2s_interface
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USB Audio 2 implicit feedback sample playing stereo and recording mono audio
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on I2S interface.
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Overview
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********
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This sample demonstrates how to implement USB asynchronous bidirectional audio
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with implicit feedback. The host adjusts number of stereo samples sent for
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headphones playback based on the number of mono microphone samples received.
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.. warning::
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Microsoft Windows USB Audio 2.0 driver available since Windows 10,
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release 1703 does not support implicit feedback.
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Requirements
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************
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Target must be able to measure I2S block start (i.e. first sample from output
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buffer gets out) relative to USB SOF. The relative offset must be reported with
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single sample accuracy.
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This sample has been tested on :zephyr:board:`nrf5340dk`. While for actual audio
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experience it is necessary to connect external I2S ADC and I2S DAC, simple echo
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can be accomplished by shorting I2S data output with I2S data input.
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Theoretically it should be possible to obtain the timing information based on
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I2S and USB interrupts, but currently neither subsystem currently provides
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necessary timestamp information.
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Building and Running
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********************
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The code can be found in :zephyr_file:`samples/subsys/usb/uac2_implicit_feedback`.
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To build and flash the application:
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.. zephyr-app-commands::
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:zephyr-app: samples/subsys/usb/uac2_implicit_feedback
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:board: nrf5340dk/nrf5340/cpuapp
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:goals: build flash
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:compact:
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