Introduction
The aJile JEMBlazer JFlame-DevKit Java Gaming Cartridge is a computing platform
designed for playing Java MIDP games, running other MIDlet applications,
and playing MP3 music. MIDlets and MP3 files may be easily downloaded
from the Internet, and loaded and played on the JEMBlazer cartridge.
The JEMBlazer cartridge uses the Nintendo Game Boy Advance to display
a "desktop" interface to the MIDlets, to display game graphics, and to
provide keypad inputs. The JEMBlazer cartridge platform is designed to leverage
Sun Microsystems' J2ME / CLDC / MIDP Java APIs.
Following is information that is needed to develop Java MIDlets that
will run on aJile's JEMBlazer Java Gaming Cartridge, the JFlame-DevKit. top
^ What You Received in the JFlame-DevKit Developer's Kit The JFlame-DevKit Developer's Kit contains the following items:
- aJile JEMBlazer cartridge with MultiMedia Card (MMC) socket
- Expansion pod (14-pin socket, RJ-45 socket, JFlame-DevKit adapter plug,
and 2 LEDs)
- Parallel port adapter card (RJ-45 and DB-25 sockets)
- Serial port adapter card (two male DB-9 connectors)
- Serial port adapter cable (gray, 12-inch, 14-pin ribbon cable)
- JTAG cable (white, 7-foot cable with RJ-45 plugs)
- 6-foot mini USB cable
- JFlame-DevKit Developer Software Installation Kit (on CD-ROM or web
site)
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What You Will Also Need For developing MIDlets for the JEMBlazer, you will also need the following
equipment, not supplied:
- PC running Windows 9x/Me/NT/2000/XP with a parallel port, USB port,
85 MB of available hard disk space, and Internet connection. Administrative
privileges are required to install the aJile Tool Suite on some systems.
- A device for writing files from a PC to a MultiMedia Card (MMC).
- Nintendo Game Boy Advance (GBA) or Game Boy Advance SP with a wall
adapter or two (2) AA batteries.
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Quickstart:
Building MIDlets for the JEMBlazer
Following is the basic method for developing and preparing MIDlets
for execution on the JEMBlazer cartridge.
Once MIDlets have been developed and are ready for use, they are loaded
onto a MultiMedia Card from a PC. When the MultiMedia Card is inserted
into the socket on the JEMBlazer cartridge, the cartridge's desktop application
manager recognizes the MIDlets.
The MultiMedia Card must remain inserted for MIDlets to remain active;
the JEMBlazer cartridge application manager recognizes ejection and insertion
of the card as an indication that a new set of MIDlets is available.
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J2ME Wireless Toolkit as Emulator Since the JEMBlazer system implements the Java MIDP graphics APIs, developers
may use their preferred MIDP emulation tools for development. For example,
Sun's J2ME Wireless
Toolkit (WTK) is a popular emulation environment that provides tools
for producing JAD and JAR files from Java source code. The Wireless
Toolkit emulator may use these JAD and JAR files, and they may also be
transformed into a format that is executable on the JEMBlazer cartridge.
A new "skin" (device definition) for the Wireless Toolkit is provided
by aJile to help developers create MIDlets for the JEMBlazer cartridge.
This skin makes the Wireless Toolkit appear similar to a Game Boy Advance
rather than the default cell phone appearance.
The notation {j2mewtk.dir} below
refers to the actual directory where the WTK is installed, say C:\WTK20
A JEMBlazer device definition, or "skin", for the Wireless Toolkit is
available with the JFlame-DevKit Developer's Kit. The "JEMBlazer/Emulator/wtklib" subdirectory
of the directory where the Developer's Kit was installed contains the
files for this JEMBlazer skin. Copy these files into the WTK installation
directory on a PC. The device definition files should be placed in the
directory {j2mewtk.dir}\wtklib\devices\JFlame-DevKit
MIDlets may be developed and tested using the WTK with the JEMBlazer skin.
Once a MIDlet appears to run satisfactorily on the WTK, the resulting
JAD and JAR files may be transformed into a format compatible with the
JEMBlazer cartridge.
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JFlame-DevKit MIDlet Builder Site The basic method for transforming JAD and JAR files into a format useable
on the JEMBlazer cartridge is to visit the aJile JFlame-DevKit
Build Page. The build web page does not require tool installation,
other than a web browser and Internet connection.
Follow the instructions on the JFlame-DevKit build web page. You will
need to supply file pathnames or URLs for the JAD and JAR files that
were produced with the WTK or other development tool. After processing
on the build site, you will be asked for a directory in which to save
the resulting binary file for loading onto a MMC card for use in the
JEMBlazer cartridge.
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Copy MIDlets to MMC Card Next, copy the appropriate MIDlet binary files (generated above) from
the PC to a MultiMedia Card in the proper directory. The following table
indicates which directories are appropriate for which kind of file type.
Expected Layout of the MultiMedia Card Directories
| Directory Name |
Purpose and Description |
| / (i.e.: root) |
Desktop display |
| /Games |
MIDlet game binary files |
| /Music |
MP3 files; note that MP3 files must be placed in this directory
to be displayed with special icons |
| /Tools |
Other MIDlet application binary files |
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Run MIDlets on the JEMBlazer Finally, the MultiMedia Card is inserted into the JEMBlazer cartridge
socket. When the Game Boy Advance with a JEMBlazer cartridge is turned on,
the desktop application manager will "discover" MIDlet applications and
will allow the user to select an application to be run.
DON'T REMOVE THE MMC CARD when:
- Dialogs are present stating that the application is loading, or
- Menus are being read, or
- Folders are being updated
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MIDlet Development Information
The following table indicates Game Boy Advance button equivalents for
use in MIDlet development. Empty table entries indicate an unused or
unassigned action.
GBA Button Assignments
| GBA Button |
MIDP UI Name |
JEMBlazer Function |
| START button |
SELECT/FIRE |
Selects an item in a menu, or starts a selected MIDlet or MP3
file |
| A button |
GAME_A |
Selects an item in a menu, or starts a selected MIDlet or MP3
file |
| B button |
GAME_B |
|
| Left "shoulder" |
GAME_D |
|
| Right "shoulder" |
GAME_C |
|
| 4 way cursor |
UP/DOWN/LEFT/RIGHT |
Navigate among folders/icons on desktop |
| SELECT button |
|
"Meta" key (not passed to MIDP) |
| Meta-A |
SOFT2 |
'About' dialog |
| Meta-B |
SOFT1 |
|
- The START and 'A' buttons are the action buttons; either selects
items in menus, starts MIDlets, etc.
- MIDlets with no associated icon will be represented by the
JEMBlazer logo.
- The space along the bottom of the screen
is reserved for status icons (MMC/MP3/etc.)
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Updating the Desktop Software The JEMBlazer cartridge is delivered with a desktop interface allowing
access to MIDlets and other features. A future release of the JFlame-DevKit
Developer's Kit will allow modification of the JEMBlazer cartridge desktop
operation.
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MIDP 2.0 Implementation Notes The following should be noted when developing MIDlets using MIDP 2.0
for the JEMBlazer cartridge. Some of these items are due to the nature of
the GBA and cartridge hardware. aJile Systems plans to continue to improve
the MIDP 2.0 implementation for the JEMBlazer cartridge.
- Game sound capabilities are unimplemented (although MP3 files may
be played)
- Scalable Polyphony MIDI sound support is unimplemented
- A numeric keypad is unavailable, only the keys on the Game Boy Advance
are defined
- Currently only one (1) MIDlet per MIDlet suite is recognized by
the MIDletBuilder
- Networking features (e.g. HTTP, sockets, datagrams) are not present,
since the GBA currently doesn't have any networking capability
- Over-the-Air provisioning is unavailable
- Trusted MIDlet security (e.g. PKI, certificates) is not provided
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