60 lines
2.7 KiB
HTML
60 lines
2.7 KiB
HTML
<html devsite>
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<head>
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<title>Android Open Accessory (AOA)</title>
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<meta name="project_path" value="/_project.yaml" />
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<meta name="book_path" value="/_book.yaml" />
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</head>
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<body>
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<!--
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Copyright 2017 The Android Open Source Project
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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<p>Android Open Accessory (AOA) support allows external USB hardware
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(Android USB accessories) to interact with Android-powered devices in
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<em>accessory mode</em>. When an Android-powered powered device is in
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accessory mode, the connected accessory acts as the USB host (powers the bus and
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enumerates devices) and the Android-powered device acts as the USB accessory.
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</p>
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<p>Android USB accessories are designed to attach to Android-powered devices.
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Such accessories adhere to AOA, enabling them to detect Android-powered devices
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that support accessory mode, and must provide 500mA at 5V for charging power.
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Some previously-released Android-powered devices are capable of acting only
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as a USB device and cannot initiate connections with external USB devices. AOA
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support overcomes this limitation, enabling you to build accessories that can
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initiate connections and interact with an assortment of Android-powered devices.
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</p>
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<p class="note"><strong>Note:</strong> Accessory mode is dependent on device
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hardware; not all devices support accessory mode. Devices that support accessory
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mode can be filtered using a <code><uses-feature></code> element in the
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corresponding application's Android manifest. For details, see the
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<a href="http://developer.android.com/guide/topics/connectivity/usb/accessory.html#manifest">USB
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Accessory</a> developer guide.</p>
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<p>AOA has two versions that support different types of communication:</p>
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<ul>
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<li><strong>AOAv1</strong>. Supports generic accessory communication and adb
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debugging. Available in Android 3.1 (API Level 12) and higher and supported
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through an
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<a href="https://developers.google.com/android/add-ons/google-apis/">Add-On
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Library</a> in Android 2.3.4 (API Level 10) and higher.</li>
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<li><strong>AOAv2</strong>. Supports audio streaming and human interface
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device (HID) capabilities. Available in Android 4.1 (API Level 16).</li>
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</ul>
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</body>
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</html>
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