1 page.title=Android Open Accessory Protocol 2 @jd:body 3 4 <!-- 5 Copyright 2013The Android Open Source Project 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18 --> 19 20 <p> Android Open Accessory support allows external USB hardware (an Android USB accessory) to interact 21 with an Android-powered device in a special accessory mode. When an Android-powered powered device 22 is in accessory mode, the connected accessory acts as the USB host (powers the bus and enumerates 23 devices) and the Android-powered device acts in the USB accessory role. Android USB accessories are 24 specifically designed to attach to Android-powered devices and adhere to the Android Open Accessory 25 Protocol, that allows them to detect Android-powered devices that support 26 accessory mode. Accessories must also provide 500mA at 5V for charging power. Many previously 27 released Android-powered devices are only capable of acting as a USB device and cannot initiate 28 connections with external USB devices. Android Open Accessory support overcomes this limitation 29 and allows you to build accessories that can interact with an assortment of Android-powered 30 devices by allowing the accessory to initiate the connection.</p> 31 32 33 <p><strong>Note:</strong> Accessory mode is ultimately dependent on the device's hardware and not all devices 34 support accessory mode. Devices that support accessory mode can be filtered using a <code><uses-feature></code> 35 element in your corresponding application's Android manifest. For more information, see the 36 <a href="http://developer.android.com/guide/topics/connectivity/usb/accessory.html#manifest">USB Accessory</a> 37 developer guide.</p> 38 39 40 <p>Android Open Accessory support is included in Android 3.1 (API Level 12) and higher, and supported 41 through an <a href="https://developers.google.com/android/add-ons/google-apis/">Add-On Library</a> in Android 42 2.3.4 (API Level 10) and higher.</p> 43 44 45
