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Android のusb support
This document discusses USB support and open accessory protocols for Android devices. It covers built-in Android USB functions like mass storage and tethering. It also discusses limitations like lack of USB host support on most devices. The document introduces the open accessory protocol for communication between peripherals and Android via USB. It provides examples of accessory hardware kits and describes requirements for open accessory devices. Finally, it outlines the APIs and processes for connecting Android applications to USB accessories.
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Android のusb support
- 1. Android のUSB support まごろく
- 2. USB on AndroidYesterday • Android USB device built-in functions – USB mass storage – Adb – USB tethering • Limitations – Most Android devices have no USB host support – USB Host in Android 3.0 is very limited – No USB APIs
- 3. What is anOpen Accessory • Simple USB protocol for communication between peripherals and Android devices • Accessory is the host, Android is the device • Bi-directional communication over two bulk end points • protocol for associating Android applications with the hardware they support
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- 5. ADK • Android AccessoryBoard: – Based on arduino Mega 2560 – Maxim MAX3421E host controller – Works with arduino tool chain
- 6. Google Shield • 3 RGB LEDs • 4 buttons (3 channels, 1 capacitive) • 3 servo channels, 2 relays • joystick • light & temperature sensors
- 7. Requirements for Open Accessory Hardware • USB host • Must supply 500mA @5V charging power
- 8. Open Accessory Handshake •When a new device connected, the accessory will perform these steps: – Send "Get Protocol" command to get Accessory protocol version. if they fails, the device does not support accessories – Send manufacture, mode description version, serial number and URL strings to identify the accessory to the Android Device – Send "start" command – The Android device should re-enumerate in accessory mode and launch an app
- 9. USB Accessory Handshake,part2 • You're in Accessory Mode if: – vendor ID is 0x18d1 (Google) – Product ID is 0x2D00 or 0x2D01 • Read configuration descriptors • Look for first In and first bulk OUT endpoint • Set configuration to 1 • Endpoints are now ready for communication
- 10. Open Accessory APIs •New USB APIs in Android 3.1 • - com.android.hardware.udb.* • - Use the is your app will require Android 3.1 (API 12) or later • - Supported on Motorola Xoom with android 3.1 update • Compatibility Library for Gingerbread • - com.andorid.future.ubs.* • - Link against com.android.future.usb.accessory.jar • - Very similar to Android 3.1 API • - Use this if you want to support Gingerbread and later • - Supported on Nexus One and Nexus S with 2.3.4 update
- 11. Connecting to andAccessory • Application describes compatible accessories in manifest meta-data • USB Manager matches accessory to compatible application(s) • Asks user if it is OK to use your app with the accessory to choose among multiple applications • Application's Activity is started with USB_ACCESSORY_ATTACHED Intent • Association made permanent if the user selects "always use the app for this accessory" in this dialog • USB_ACCESSORY_DETACHED Intent send when accessory disconnected
- 12. UsbAccessory class • Describesthe USB accessory base on the strings if provides in the handshake – manufacture Name – Model Name – Description (user-visible strings) – URL (web page to visit if no installed support the accessory) • Serial Number (Optional) • Manufacture, Model and Version are used for associating accessories with applications
- 13. USB Manager class •getAccessoryList() return currently attached accessories (currently these can only one) • openAccessory() returns a ParcelFileDescriptor • hasPermission() to see if you have access to the accessory • requestPermission() to request permission from user
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- 15. arduino • open-source electronicsprototyping platform • http://www.arduino.cc/ • http://www.circuitsathome.com/arduino_usb _host_shield_projects
- 16. ATmega2560 • ATmega2560 フラッシュメモリ256KB • SRAM 8KB • EEPROM 4KB • デジタルI/O 54本 PWM I2C含 • アナログ入力 16本
- 17. USB Host • MAX3421Eが乗ってるだけ
- 18. よーするに Shield AVR マイコン USB HOST
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- 21. Hrdakinoriさん • 4月ごろからPIC24F OTG付きで実験 •https://github.com/hrdakinori/ADB_PIC24F
- 22. 結論 • おもちゃ・遊び場が増えて • 睡眠時間が減る •Androidアプリ書けないけどDeviceの prototypingはできます • PIC24F OTG付き 64Kbyte DIP版入手 いっしょに遊ぶ人募集