JHDL is a low-level structural hardware description language

Hardware description language

In electronics, a hardware description language or HDL is any language from a class of computer languages, specification languages, or modeling languages for formal description and design of electronic circuits, and most-commonly, digital logic...

, focused primarily on building circuits via an Object Oriented

Object-oriented programming

Object-oriented programming is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction,...

 approach that bundles collections of gates into Java objects. Implemented as a toolset and class library on top of the Java programming language

Java (programming language)

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...

, its primary use is for the design of digital circuits for implementation in field-programmable gate arrays (FPGAs). Particular attention was paid to supporting the Xilinx

Xilinx

Xilinx, Inc. is a supplier of programmable logic devices. It is known for inventing the field programmable gate array and as the first semiconductor company with a fabless manufacturing model....

 series of chips.

When the design is ready to be placed in a fabric, the developer simply generates an Electronic Design Interchange Format

EDIF

EDIF is a vendor-neutral format in which to store Electronic netlists and schematics. It was one of the first attempts to establish a neutral data exchange format for the electronic design automation industry. The goal was to establish a common format from which the proprietary formats of the EDA...

 (EDIF) netlist

Netlist

The word netlist can be used in several different contexts, but perhaps the most popular is in the field of electronic design. In this context, a "netlist" describes the connectivity of an electronic design....

 and imports it into his favorite toolkit. Once imported, the developer should be able to transfer the circuit via a Joint Test Action Group

JTAG

Joint Test Action Group is the common name for what was later standardized as the IEEE 1149.1 Standard Test Access Port and Boundary-Scan Architecture. It was initially devised for testing printed circuit boards using boundary scan and is still widely used for this application.Today JTAG is also...

 (JTAG) cable. EDIF netlisting is supported for the XC4000, Virtex, and Virtex-II series of FPGAs.

JHDL was developed at BYU

Brigham Young University

Brigham Young University is a private university located in Provo, Utah. It is owned and operated by The Church of Jesus Christ of Latter-day Saints , and is the United States' largest religious university and third-largest private university.Approximately 98% of the university's 34,000 students...

 in the Configurable Computing Laboratory, the project initiated in 1997.

Features

The JHDL language features include:

• Structural hardware design
• Flexible module generators
• Table-generated finite state machines
• A graphical "Workbench" toolkit

Behavioral synthesis is not yet fully supported.

The integrated JHDL Workbench environment is designed to allow developers to graphically test and trace their circuit designs. This tool includes:

• A graphical schematic viewer
• A multiclock cycle-based simulator
• A command line interface
• A complete list of all wires and gates
• A complete status of all values passing through the circuit

Naming

Originally, the J in "JHDL" stood for "Java". However, to prevent trademark issues, the name has been backronym

Backronym

A backronym or bacronym is a phrase constructed purposely, such that an acronym can be formed to a specific desired word. Backronyms may be invented with serious or humorous intent, or may be a type of false or folk etymology....

ed to stand for Just-Another Hardware Description Language.