Difference between revisions of "DESK-MX8M-AN-0002: Adding an audio interface with an USB bluetooth audio transmitter"
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==USB bluetooth audio kernel driver== | ==USB bluetooth audio kernel driver== | ||
| − | Once plugged on USB-C connector, using | + | Once plugged on USB-C connector, using an USB-C to USB-A adapter like [https://www.amazon.com/Adapter-JSAUX-Compatible-MacBook-Samsung/dp/B07L749R9R this], the kernel identify the BT adapter with the following ID: |
<pre class="board-terminal"> | <pre class="board-terminal"> | ||
| Line 55: | Line 55: | ||
</pre> | </pre> | ||
| − | where <code>card0</code> is the | + | where <code>card0</code> is the audio device used for the audio interface instantiated. |
== Accessing the audio device == | == Accessing the audio device == | ||
Here below a simple command used for testing the audio interface. | Here below a simple command used for testing the audio interface. | ||
| − | Once the BT audio speaker has been paired with the USB audio adapter, the audio adapter | + | Once the BT audio speaker has been paired with the USB audio adapter, the audio adapter can be tested with: |
<pre class="board-terminal"> | <pre class="board-terminal"> | ||
| − | root@desk-mx8mp:~# speaker-test | + | root@desk-mx8mp:~# speaker-test -c 1 -t wav |
| − | |||
| − | |||
Playback device is default | Playback device is default | ||
Stream parameters are 48000Hz, S16_LE, 1 channels | Stream parameters are 48000Hz, S16_LE, 1 channels | ||
| − | + | WAV file(s) | |
Rate set to 48000Hz (requested 48000Hz) | Rate set to 48000Hz (requested 48000Hz) | ||
Buffer size range from 3840 to 5760 | Buffer size range from 3840 to 5760 | ||
| Line 78: | Line 76: | ||
was set buffer_size = 5760 | was set buffer_size = 5760 | ||
0 - Front Left | 0 - Front Left | ||
| − | Time per period = | + | Time per period = 1.393268 |
| − | + | 0 - Front Left | |
| + | Time per period = 1.479779 | ||
| + | 0 - Front Left | ||
| + | Time per period = 1.479839 | ||
| + | 0 - Front Left | ||
| + | ... | ||
</pre> | </pre> | ||
Revision as of 12:45, 3 May 2022
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 This application note has been validated using the kit version in the History table. |
Contents
History[edit | edit source]
| Version | Date | Development Kit version |
|---|---|---|
| 1.0.0 | Apr 2022 | DESK-MX8M-L 2.0.0-rc2 |
Introduction[edit | edit source]
ORCA SOM has multiple SAI interfaces. In the ORCA EVK the SAI2 interface signals can be used to connect an external I2S codec for using the native audio interface.
This application note describes how to simply add another audio interface using a standard bluetooth to audio adapter like the Avantree DG80 USB to audio transmitter
USB bluetooth audio kernel driver[edit | edit source]
Once plugged on USB-C connector, using an USB-C to USB-A adapter like this, the kernel identify the BT adapter with the following ID:
root@desk-mx8mp:~# lsusb | grep DG80 Bus 001 Device 003: ID 0a12:1004 Cambridge Silicon Radio, Ltd Avantree DG80 root@desk-mx8mp:~#
and the kernel installs the proper device driver:
root@desk-mx8mp:~# [ 57.058086] usb 1-1: new full-speed USB device number 3 using xhci-hcd [ 57.302616] input: Avantree DG80 Consumer Control as /devices/platform/32f10108.usb/38200000.dwc3/xhci-hcd.1.auto/usb1/1-1/1-1:1.3/0003:0A12:1004.0002/input/input3 [ 57.386964] input: Avantree DG80 as /devices/platform/32f10108.usb/38200000.dwc3/xhci-hcd.1.auto/usb1/1-1/1-1:1.3/0003:0A12:1004.0002/input/input4 [ 57.400528] hid-generic 0003:0A12:1004.0002: input: USB HID v1.11 Device [Avantree DG80] on usb-xhci-hcd.1.auto-1/input3 root@desk-mx8mp:~#
audio device[edit | edit source]
If the kernel driver is present, the kernel creates the audio interface that can be listed with aplay e.g.
root@desk-mx8mp:~# aplay -l **** List of PLAYBACK Hardware Devices **** card 0: DG80 [Avantree DG80], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 root@desk-mx8mp:~#
where card0 is the audio device used for the audio interface instantiated.
Accessing the audio device[edit | edit source]
Here below a simple command used for testing the audio interface.
Once the BT audio speaker has been paired with the USB audio adapter, the audio adapter can be tested with:
root@desk-mx8mp:~# speaker-test -c 1 -t wav Playback device is default Stream parameters are 48000Hz, S16_LE, 1 channels WAV file(s) Rate set to 48000Hz (requested 48000Hz) Buffer size range from 3840 to 5760 Period size range from 1920 to 1920 Using max buffer size 5760 Periods = 4 was set period_size = 1920 was set buffer_size = 5760 0 - Front Left Time per period = 1.393268 0 - Front Left Time per period = 1.479779 0 - Front Left Time per period = 1.479839 0 - Front Left ...
