USB accessories are peripherals that connect to android devices as a USB host.
When connected, the accessory will first identify itself to the android device
by sending manufacturer, product, accessory type and version strings
to the device, and then request the device to enter USB accessory mode.
The device will then enable the USB accessory kernel driver and disable
all other USB functionality except possibly adb
(adb can be used while the android device is connected to the PC
and the PC is running software that emulates a USB accessory)
The class android.hardware.UsbAccessory is used to describe the
currently attached USB accessory.
UsbAccessory contains the manufacturer, product, accessory type
and version strings to identify the accessory.
The accessory can be opened as a ParcelFileDescriptor, which can be used
to communicate with the accessory over two bulk endpoints.
The Intents UsbManager.USB_ACCESSORY_ATTACHED and
UsbManager.USB_ACCESSORY_DETACHED are broadcast when accessories are
connected and disconnected to the device. The USB_ACCESSORY_ATTACHED
contains a UsbAccessory object for the attached accessory as an extra.
The Intent also contains string extras for the manufacturer, product,
accessory type and version strings to allow filtering on these strings.
Change-Id: Ie77cbf51814a4aa44a6b1e62673bfe4c6aa81755
Signed-off-by: Mike Lockwood <lockwood@android.com>
UsbManager:
- is now a service retrievable via Context.getSystemService(Context.USB_SERVICE).
- provides support for returning a list all connected USB devices
- broadcasts ACTION_USB_DEVICE_ATTACHED and USB_DEVICE_DETACHED when devices
are added and removed from the USB host bus
UsbDevice:
- represents an attached USB device.
UsbInterface:
- represents an interface on a USB device
- devices may have multiple interfaces if they provide multiple
sets of functionality (for example, android phones typically have interfaces
for both USB mass storage and adb)
UsbEndpoint:
- represents an endpoint on a USB interface
- endpoints are used for sending or receiving data
(only in one or the other direction)
UsbRequest:
- encapsulates a send or receive request to be sent over an endpoint
Change-Id: Ieef3e434c62760770ea839070cf5eba1a705967a
Signed-off-by: Mike Lockwood <lockwood@android.com>
A new USB host API will be added in an upcoming commit
Change-Id: I5816c10c7acd236d31ab8ae255fc83c77121eea0
Signed-off-by: Mike Lockwood <lockwood@android.com>
In preparation for an upcoming change that will make UsbService into a real system service
Change-Id: Id85d624cfc6b10b49a08105cfaaacc667a492c12
Signed-off-by: Mike Lockwood <lockwood@android.com>
