125 lines
6.8 KiB
Markdown
125 lines
6.8 KiB
Markdown
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## 7.7\. USB
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If device implementations have a USB port, they:
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* SHOULD support USB peripheral mode and SHOULD support USB host mode.
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### 7.7.1\. USB peripheral mode
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If device implementations include a USB port supporting peripheral mode:
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* [C-1-1] The port MUST be connectable to a USB host that has a standard
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type-A or type-C USB port.
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* [C-1-2] MUST report the correct value of `iSerialNumber` in USB standard
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device descriptor through `android.os.Build.SERIAL`.
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* [C-1-3] MUST detect 1.5A and 3.0A chargers per the Type-C resistor
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standard and MUST detect changes in the advertisement if they support
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Type-C USB.
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* [SR] The port SHOULD use micro-B, micro-AB or Type-C USB form factor.
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Existing and new Android devices are **STRONGLY RECOMMENDED to meet these
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requirements** so they will be able to upgrade to the future platform releases.
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* [SR] The port SHOULD be located on the bottom of the device
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(according to natural orientation) or enable software screen rotation for
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all apps (including home screen), so that the display draws correctly when
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the device is oriented with the port at bottom. Existing and new Android
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devices are **STRONGLY RECOMMENDED to meet these requirements** so they will
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be able to upgrade to future platform releases.
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* [SR] SHOULD implement support to draw 1.5 A current during HS chirp
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and traffic as specified in the [USB Battery Charging specification, revision 1.2](http://www.usb.org/developers/docs/devclass_docs/BCv1.2_070312.zip).
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Existing and new Android devices are **STRONGLY RECOMMENDED to meet these
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requirements** so they will be able to upgrade to the future platform releases.
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* [SR] STRONGLY RECOMMENDED to not support proprietary
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charging methods that modify Vbus voltage beyond default levels, or alter
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sink/source roles as such may result in interoperability issues with the
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chargers or devices that support the standard USB Power Delivery methods. While
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this is called out as "STRONGLY RECOMMENDED", in future Android versions we
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might REQUIRE all type-C devices to support full interoperability with standard
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type-C chargers.
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* [SR] STRONGLY RECOMMENDED to support Power Delivery for data and
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power role swapping when they support Type-C USB and USB host mode.
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* SHOULD support Power Delivery for high-voltage charging and support for
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Alternate Modes such as display out.
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* SHOULD implement the Android Open Accessory (AOA) API and specification as
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documented in the Android SDK documentation.
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If device implementations include a USB port and implement the AOA
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specification, they:
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* [C-2-1] MUST declare support for the hardware feature
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[`android.hardware.usb.accessory`](http://developer.android.com/guide/topics/connectivity/usb/accessory.html).
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* [C-2-2] The USB mass storage class MUST include the string "android" at the
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end of the interface description `iInterface` string of the USB mass storage
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* SHOULD NOT implement [AOAv2 audio](https://source.android.com/devices/accessories/aoa2#audio-support)
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documented in the Android Open Accessory Protocol 2.0 documentation. AOAv2 audio
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is deprecated as of Android version 8.0 (API level 26).
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### 7.7.2\. USB host mode
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If device implementations include a USB port supporting host mode, they:
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* [C-1-1] MUST implement the Android USB host API as documented in the
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Android SDK and MUST declare support for the hardware feature
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[`android.hardware.usb.host`](http://developer.android.com/guide/topics/connectivity/usb/host.html).
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* [C-1-2] MUST implement support to connect standard USB peripherals,
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in other words, they MUST either:
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* Have an on-device type C port or ship with cable(s) adapting an on-device
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proprietary port to a standard USB type-C port (USB Type-C device).
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* Have an on-device type A or ship with cable(s) adapting an on-device
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proprietary port to a standard USB type-A port.
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* Have an on-device micro-AB port, which SHOULD ship with a cable adapting
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to a standard type-A port.
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* [C-1-3] MUST NOT ship with an adapter converting from USB type A or
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micro-AB ports to a type-C port (receptacle).
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* [C-SR] Are STRONGLY RECOMMENDED to implement the [USB audio class](
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http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO)
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as documented in the Android SDK documentation.
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* SHOULD support charging the connected USB peripheral device while in host
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mode; advertising a source current of at least 1.5A as specified in the
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Termination Parameters section of the
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[USB Type-C Cable and Connector Specification Revision 1.2](
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http://www.usb.org/developers/docs/usb_31_021517.zip) for USB Type-C
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connectors or using Charging Downstream Port(CDP) output current range as
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specified in the [USB Battery Charging specifications, revision 1.2](
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http://www.usb.org/developers/docs/devclass_docs/BCv1.2_070312.zip)
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for Micro-AB connectors.
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* SHOULD implement and support USB Type-C standards.
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If device implementations include a USB port supporting host mode and the USB
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audio class, they:
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* [C-2-1] MUST support the [USB HID class](https://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_HID).
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* [C-2-2] MUST support the detection and mapping of the following HID data
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fields specified in the [USB HID Usage Tables](http://www.usb.org/developers/hidpage/Hut1_12v2.pdf)
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and the [Voice Command Usage Request](http://www.usb.org/developers/hidpage/Voice_Command_Usage.pdf)
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to the [`KeyEvent`](https://developer.android.com/reference/android/view/KeyEvent.html)
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constants as below:
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* Usage Page (0xC) Usage ID (0x0CD): `KEYCODE_MEDIA_PLAY_PAUSE`
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* Usage Page (0xC) Usage ID (0x0E9): `KEYCODE_VOLUME_UP`
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* Usage Page (0xC) Usage ID (0x0EA): `KEYCODE_VOLUME_DOWN`
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* Usage Page (0xC) Usage ID (0x0CF): `KEYCODE_VOICE_ASSIST`
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If device implementations include a USB port supporting host mode and
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the Storage Access Framework (SAF), they:
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* [C-3-1] MUST recognize any remotely connected MTP (Media Transfer Protocol)
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devices and make their contents accessible through the `ACTION_GET_CONTENT`,
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`ACTION_OPEN_DOCUMENT`, and `ACTION_CREATE_DOCUMENT` intents. .
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If device implementations include a USB port supporting host mode and USB
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Type-C, they:
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* [C-4-1] MUST implement Dual Role Port functionality as defined by the USB
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Type-C specification (section 4.5.1.3.3).
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* [SR] STRONGLY RECOMMENDED to support DisplayPort, SHOULD support USB
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SuperSpeed Data Rates, and are STRONGLY RECOMMENDED to support Power Delivery
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for data and power role swapping.
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* [SR] STRONGLY RECOMMENDED to NOT support Audio Adapter Accessory Mode as
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described in the Appendix A of the
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[USB Type-C Cable and Connector Specification Revision 1.2](
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http://www.usb.org/developers/docs/).
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* SHOULD implement the Try.\* model that is most appropriate for the
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device form factor. For example a handheld device SHOULD implement the
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Try.SNK model.
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