Java bread board (JBB) simulator simulate circuits developed on a breadboard. Students can place chips on the breadboard and these chips should work just as the real hardware. In order to allow easy extendability of the system, each chip is a separate class. The user can write new classes for new chips, re-compile the applet and the new chip will be included.

However, this approach means that the application must be downloaded and re-compiled. Also, it requires that the user is able to program in Java.

The "Circuit Design Tools for a Bread-Board Simulator" project involves the development of tools that allow the user to create new chips using standard circuit design tools like schematic circuit diagrams, transition tables and boolean algebra.

The simulation software can be started at the command prompt or by double clicking on the supplied batch file. To launch this program at the command line you first need to open a command prompt:
Start -> Programs -> Accessories -> Command Prompt At the command prompt type:
c:
cd c:\temp\JavaBreadBoard
This will move you to the directory containing the simulator's class file directory hierarchy. To launch the simulator at the command prompt type:
go.bat
Alternatively you can double left click on this batch file from the file browser.

Bread boards
To assemble your virtual circuit you need at least one bread board. These can be added to the simulator by either clicking the bread board icon or click on the pull down:
Insert -> BreadBoard
This will add a bread board to the simulator as shown in figure 2 onto which integrated circuits, wires and other electronic components can be added.

Components
To add an integrated circuit to your virtual circuit either click on the 'Select and Add Chip' icon or click on the pull down:
Insert -> Chip
This will open the 'Select a Chip' window as shown in figure 3, allowing you to select from a range of pre-defined, custom or user defined integrated circuits.

Wires
To add wire interconnects to your virtual circuit either click on the 'Wiring Mode' icon or click on the pull down:
Wire -> Add Wire
Note, to allow an IC's functionality to be simulated its power supply lines must be connected using wires to VCC (top horizontal row A) and GND (bottom horizontal row L).

Simulation
When a virtual circuit has been designed its functionality can be confirmed through simulation. Test inputs to the circuit are applied using DIP switches. To view the state of specific test points the user can either add LEDs or test probes. Multiple test probes can be added to a design allowing the user to capture the state of the circuit at a specific time. To add a probe click on the pull down:
Trace -> Insert Probe
This will add a test probe to your circuit , the default position being row B, column 1. To move a test probe left click, hold and drag the probe graphic to the bread board hole you wish to monitor.

Saving and Loading Circuits
To save a virtual circuit so that the user can continue working on a design at a later time click on the 'Save' icon or click on the pull down:
File -> Save
This will open a 'Save' window allowing the user to specify an output file (.cir extension). Enter a file name and left click on the Save button.

Custom Integrated Circuits
If the required integrated circuit is not included in the pre-installed catalogue, or if the desired functionality is not available in a commercial IC the Java bread board software allows you to define a custom IC. There are two types of custom integrated circuit supported, 'logic' and 'state machine'.

User defined Integrated Circuits
If the required integrated circuit is not included in the pre-installed catalogue and can not be implemented using custom ICs, the user can define their own components.

Requirements:
* Java Runtime

The license of this software is Freeware, you can free download and free use this cad software.