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Java Chips
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Here we list some hardware Java processors that come in chip packages (as opposed to cores that are sold as circuit descriptions for implementation in different types of chips.)

Some of these chips need ancillary hardware such as power supplies, memory, and so forth, but are basically complete microprocessors. They implement Java bytecode instructions instead of conventional processor type instructions.

Other Java chips work as co-processors that assist a conventional processor to speed up the running of Java programs.

aJ-100, aJ-80 - aJile

The 32-bit aJ-100 derives from the JEMtm Java processor first developed at Rockwell Collins. It executes the full bytecode instruction set, including floating point, with extended bytecodes for I/O and threading operations. It can also implement custom bytecodes for special operations.

The processor core comes with 48 kB internal memory (16kb for microcode and 32kb for data) and can access up to 250MB external RAM via an 8-bit, 16-bit or 32 bit interface. It s includes dual UARTs, five 8 bit I/0 ports, and other I/O features.

It is suitable for real time operations and supports the RTSJ. It offers a hard real-time multi-threading kernel with synchronization and deterministic scheduling queues. The thread yield, wait, notify and monitor enter/exit are implemented directly with extended bytecodes so a RTOS is not needed to manage the threads. A thread will yield to another within 1 microsecond.

The system can implement the J2ME Connected Limited Device Configuration (CLDC) and for wireless systems can run MIDLets. Two independent applications can run simultaneously with no interference as if they were operating in two separate JVMs. A timer allocates time slices to each JVM and a separate timer is used by each JVM for thread time slices.

The company offers an optimizing linker/application builder with a graphical user interface for creating programs for the system. It will accept class files from other compilers. It statically resolves class files and eliminates unnecessary methods and fields to reduce memory requirements.

The aJ-80 provides essentially the same features as the aJ-100 but offers only an 8-bit memory interface with corresponding slower I/O.

aJile applications

Cjip Processor - Imsys

The Cjip processor provides a complete Java instruction set, including floating point operations. The chip allows for reconfiguring of internal microcode (even in real-time) and most bytecodes are implemented in microcode. Instruction sets for C/C++ and assembler are also included..

Virtual Peripherals (VPs) peform tasks such as timers, I/O, graphics processing and many other services. A VP is loaded at the microcode level and allow for fast, deterministic performance. J2ME in the CLDC configuration and MIDP profile is supported.

We discuss the Imsys hardware also in the board systems and show a demonstration program.

Javelin Stamp Interpreter Chip - Parallax

This chip is sold separately or as part of the Javelin Stamp, which comes as a 24-pin DIP module (see the Javelin Stamp section). The Stamp is nearly a complete computer system with only the need for power and a serial line to begin computing. The Java interpreter is created with the Ubicom SX48BD microcontroller chip. The chip translates Java bytecodes (actually, a subset of them) into the SX48 instructions and executes them.

See also the section on the Javelin Stamp and Demo1 & Demo 2 Javelin Stamp example applications.

JA108 Multimedia Application Processor - Nazomi

This processor comes in a standard 16-bit SRAM/FLASH memory package and plugs into the SRAM bus. It then acts as a co-processor to accelerate Java programs, particularly multimedia applications

References & Web Resources


Latest update: Dec. 15, 2004

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