Example Connection between USB Host and Android

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19 Ιουλ 2012 (πριν από 5 χρόνια και 1 μήνα)

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Example connection between USB Host and Android
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Example Connection between USB Host and Android
This example illustrates the connection between Board ET-
MEGA2560-ADK and Android through Port USB Host. In this case,
it develops program by ADB (Android Debug Bridge) by using
Library ADB of Microbridge. This example is compatible with
every Android devices versions that have been installed the
Operating System of Android version V1.5 and higher. It
divides part of developing program into 2 parts. Firstly, it
develops program in the part of Microcontroller (ET-MEGA2560-
ADK); and secondly, it develops program in the part of Android
device. In this case, it uses Program Android SDK to develop
Application of Android. There are many websites that have
published information about developing program for board by
ADB (Android Debug Bridge); in this case, we recommend the
official website of
http://developer.android.com/guide/developing/tools/adb.html
.
Example connection between USB Host and Android
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Normally, the main circuit of Board ET-MEGA2560-ADK has
been designed according to the standard of original circuit of
Google ADK Mainboard (Google’s ADK Reference design);
moreover, it has modifies some parts of sub-circuit suitably,
so Board ET-MEGA2560-ADK can develop program through Android
Open Accessory Development Kit
(ADK) instantly. Nowadays,
there are 2 main types to develop program of Android by
Android Open Accessory Development Kit
(ADK).Firstly, it
develops program by Google Open Accessories API (ADK); in this
case, it is compatible with Android devices that have been
installed Operating system of Andriod version V2.3.4 or
higher.Secondly, it develops program through
ADB (Android
Debug Bridge); in this case, it is used with Library of
Microbridge. It is compatible with Android devices that have
been installed the operating system of Android version V1.5 or
higher.
Example connection between USB Host and Android
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Android Versions
Android is the operating system as Open Source Project
from Google; it is suitable for mobile devices, especially
Android Mobile Phone and Android Tablet. This Operating System
of Android from Google is Open Source that can be developed
and improved independently; so, it attracts many developers
around the world to share the knowledge and develop program to
supply requirement until it is a large community. It uses JAVA
Language with Library of Google called “Google Developed Java
Libraries” to develop program. Google continues improving and
modifying the Library and nowadays there are more than 10
versions.
If user requires using which Compiler version and Library
version, it has to consider the Operating System of the device
that has been installed to use with program development; next,
user has to choose and set the Compiler version and the
Library version according to the Operating System in the
device.If user has set the Compiler version and the Library
version that is higher than the actual installation in the
device, the error maybe occurred because the device does not
support some instructions.
Example connection between USB Host and Android
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Android version is specified by name code (Nick Name) and
API Level; however, some details are different.So, code and
Compiler version must be matching, otherwise it cannot compile
any code program.
Android Version API Level Name Code version (Nick name)
Android 1.0 1 BASE
Android 1.1 2 BASE_1_1
Android 1.5 3 CUPCAKE
Android 1.6 4 DONUT
Android 2.0 5 ECLAIR
Android 2.0.1 6 ECLAIR_0_1
Android 2.1.x 7 ECLAIR_MR1
Android 2.2.x 8 FROYO
Android 2.3
Android 2.3.1
Android 2.3.2
9 GINGERBREAD
Android 2.3.3
Android 2.3.4
10 GINGERBREAD_MR1
Android 3.0.x 11 HONEYCOMB
Android 3.1.x 12 HONEYCOMB_MR1
Android 3.2 13 HONEYCOMB_MR2
Example connection between USB Host and Android
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Android Open Accessory Development Kit (ADK)
ADK is Android Program Development Kit that allows
external USB Host device to interface with Android Operating
System such as Android Phone and Android Tablet in the
Accessory Mode; so, Android device can act as Host.Most
devices are cheap such as mobile phones;it can communicate
with external device through USB Bus according to conditions
and restrictions of ADK.The format of Protocol ADK can reduce
difficulty in communicating through USB of mobile phones. In
this case, it moves the difficulty in communicating to the
side of USB Host that is the outside of mobile phone instead.
This capability is compatible with devices that have been
installed the Android Operating System from version 2.3.4 (for
old version that has been released) to version 3.1(for new
product release).Accessory devices that are interfaced with
Android devices in this operation mode must has own Power
Supply; moreover, it cans also supply 5V/500mA to Android
device to charge current for Android device.
Android Debug Bridge (ADB)
This is the format of developing program that is
Application for external devices; so, Android device can
communicate and command various Input/output with external
devices. In this case, user can apply cheap Android devices in
the market for many applications; it seems to increase
unlimited Input/Output systems into mobile phones.This
capability is included in all Android device versions that
have been installed the Operating System version 1.5 or
higher; so,it can support almost devices in the market that
have been installed the Operating System of Android.
If interfacing Board ET-MEGA2560-ADK with mobile phone
that has been installed the Operating System of Android,it
looks like Board ET-MEGA2560-ADK acts as I/O of mobile phone;
moreover, it is controlled and commanded by mobile phone
through Cable USB.So, it seems that the mobile phone has the
system of Input/Output that is both Digital and Analog,
including other special Input/Output such as I2C, PWM, USART
and so on.
When user has studied and understood the format of
communication between Android devices well, user can create
and build many applications for using with mobile phones. For
example, it controls ON/OFF the operation of electric
appliances, including detect signal from the designed Sensors
or detectors.
Example connection between USB Host and Android
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The following example is a guideline to connect Android
device with Board ET-MEGA2560-ADK; this example is modified
from Library ADB of Microbridge.It uses the capability of GUI
that uses touch screen and the display screen of mobile phone
to command and display operating result of Input/Output of
Board ET-MEGA2560-ADK. The operating result of program is to
command ON/OFF LED(D13) on Board ET-MEGA2560-ADK according to
the control of touch screen.In the meanwhile, Board ET-
MEGA2560-ADK sends the result of converting signal from
Analog(ADC0) and then sends back to the Android device.
It shows result of example program by Emulator of Android.
Example connection between USB Host and Android
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How to test operation
The method to test the operation of this example is to
develop program for 2 sides; Microcontroller and Android
device.On the side of Microcontroller, it uses Board ET-
MEGA2560-ADK and it develops program through Program Arduino
with ADB Library of Microbridge.On the side of Android
device, it uses computer PC with Program JAVA and Android
Library of Google to be tool to develop program.
First of all, user has to compile and upload program in
the part of Microcontroller into Board ET-MEGA2560-ADK by
Program Arduino first.Moreover,user has to copy Library ADB
for AVR Microcontroller that has been developed and modified
by Microbridge and then paste it in the Folder “..\arduino-
0022\libraries”. So, signals can directly interface with
Hardware System of Board ET-MEGA2560-ADK as shown in the
example below;
After user has installed ADB Library successfully, user
can call IDE of Arduino, open the example file program and
upload it into Board ET-MEGA2560-ADK instantly.
Example connection between USB Host and Android
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For the part of Hardware Board, it uses LED(D13) to
display the operating result of ON/OFF that is commanded by
from Android device; and it uses Signal Analog Pin A0 to
receive Input Voltage and then convert it into data for
sending and displaying on the screen of Andriod device.
Moreover,user has to interface Input Voltage from Adjustable
Resistor to adjust 0-5V Input Voltage according with Pin A0 to
test the operation of program.
Example connection between USB Host and Android
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How to prepare ADK Development kit
1.Download and install Program JDK (Java Developer Kit)
2.Download and install Program Android SDK
3.Download and install program Eclipse IDE
4.Install Program ADT (Android Development Tool) Plugin

1.Download and install Program JDK (Java Developer Kit).
This is Java Language Program that includes various
essential Libraries to develop program for Android.User
can directly download and install the program from web
page;
http://www.oracle.com/technetwork/java/javase/downloads/i
ndex.html
; in this case, it has to connect Internet to
computer PC to install program.When it has already
connected to the web page of Download, choose Tab
Download of Java Platform(JDK); next, choose Accept
License Agreement to choose the program version that user
requires downloading. In this case, user has to choose
the program version according to the actual Operating
System of computer. Finally, user has to follows
instructions of installation.
Example connection between USB Host and Android
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Load from:
http://www.oracle.com/technetwork/java/javase/downloads/java-se-jdk-7-download-432154.html
Example connection between USB Host and Android
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2.Download and install Program Android SDK. User has to
choose and set values according to the actual Operating
System that has been installed in computer PC.If using
with Windows, there are 2 choices;Zip File and Install
File
. In this case, it is better to choose version
File
Install because it is more convenient.When user has
downloaded the program successfully, should install in
Folder “C:\android-sdk-windows” because it is more
convenient to call.Next, choose Package for installation
as Accept All; in this case, it takes a long time for
processing.

Example connection between USB Host and Android
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3.Download and install Program Eclipse IDE.

Example connection between USB Host and Android
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4.Install Program ADT (Android Development Tool) Plugin.
This Program ADT links files and sub-programs that are
essential and related to develop program for ADK; so, it
is more convenient to call and command program through
window IDE of Program Eclipse correctly. User has to
install this Plugin while connecting Internet; click Menu
Help  Install New Software…

Example connection between USB Host and Android
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Set values in the window Install completely. Firstly, set
the value in the blank of Work with as Add…; secondly, set
Path value for downloading Program Plugin by setting Name as
ADT
; thirdly, set Path value in the blank of
Location:
as
https://dl-ssl.google.com/android/eclipse/
; and finally,
click OK.User has to wait for a while and the program shows
additional Developer Tools, user has to tick the check box
and click Next to go to the next step.
After user has clicked Next, program shows details,
conditions, and restrictions for using program; click I
accept the terms of license agreements to accept the
conditions; and finally, click Finish.Next, program starts
installing files instantly; in this case, it takes a long
time to process, depending on speed of internet network.
Please wait until the installing process is complete.
Example connection between USB Host and Android
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Example connection between USB Host and Android
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Testing Example Application
1.Copy the example program that has been developed by ADK;
paste and save in the Hard Disk as shown in the example
below;
2.Run Program Eclipse; and set location of program in the
blank of Worksheet according to the location that saved
the example file; in this case, it is the location
“C:\DEMO_MEGA2560_ADK” as shown in the example below;
Example connection between USB Host and Android
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Click Menu File  Import…; choose Existing Projects into
Workspace; click Next and finally, click
“C:\DEMO_MEGA2560_ADK”

Example connection between USB Host and Android
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After user has already set Directory successfully, the
program shows lists of all Project File in the Directory; in
this case, user can tick check box in front of the Project
File that user requires Import to test the operation.
After user has chosen Import Project successfully, click
Menu Windows  Preference to set location of Program SDK
Compiler for Program Eclipse. When window Preference appears,
click Tab Android;set the location that has installed Program
SDK in the blank of SDK Location as “C:\android-sdk-windows”
and then click OK.Next,click Menu Windows  Preference;
window Preference appears and click Tab Android again to check
values.If everything is correct, it shows lists of Compiler;
in this case, user can choose and click the preferred list;
and then click Apply and OK, respectively.
Example connection between USB Host and Android
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Example connection between USB Host and Android
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Example connection between USB Host and Android
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Next, click Menu Project  Properties and choose Tab Java
Compiler.User has to choose the Compiler version according to
the Operating System of the device that is used with program
development; in this case, user has to choose Enable Project
Specific Setting and set the value as Compiler Compliance
Level completely.
After user has already set the Compiler version
successfully, user can compile program instantly; click Menu
Project  Clean… to erase the old file that may be compiled by
other unwanted values. Finally, click Menu Project  Build
All.
Example connection between USB Host and Android
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Example connection between USB Host and Android
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After user has compiled successfully, it displays the
operating result in the format of File
“Mega2560ADKV233Demo.apk” and it is saved the Folder
“C:\DEMO_MEGA2560_ADK\Mega2560ADKV233Demo\bin“; in this case,
user can install this file into the Android device instantly.
If user has already installed Driver of Android device into
computer PC and connected USB Cable between computer PC and
Android device completely, user can run the operation from
Program Eclipse instantly. Program transfers files to Android
device automatically.
If user has not interfaced with Android device yet, user
can build model to test the operation instead. Program SDK Kit
has included the part of model building instead of using the
actual device. In this case, user can set specifications of
program as same as the device that is used with program
development;moreover, user can use this model building to
virtually test operation of program that has been developed by
user.Click Menu Windows  Android SDK and AVD Manager; choose
Visual Devices if user requires using the model building; or
choose Installed Packages if user requires installing program
into Android deice that is actually connecting.
Example connection between USB Host and Android
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Example connection between USB Host and Android
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Example connection between USB Host and Android
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Example connection between USB Host and Android
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Example connection between USB Host and Android
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