• Logisim home page
• Guide to Being a Logisim User
  • Beginner's tutorial
    • Step 0: Orienting yourself
    • Step 1: Adding gates
    • Step 2: Adding wires
    • Step 3: Adding text
    • Step 4: Testing your circuit
  • Libraries and attributes
    • The explorer pane
    • The attribute table
    • Tool and component attributes
  • Subcircuits
    • Creating circuits
    • Using subcircuits
    • Debugging subcircuits
    • Logisim libraries
  • Wire bundles
    • Creating bundles
    • Splitters
    • Wire colors
  • Combinational analysis
    • Opening Combinational Analysis
    • Editing the truth table
    • Creating expressions
    • Generating a circuit
  • Menu reference
    • The File menu
    • The Edit menu
    • The Project menu
    • The Simulate menu
    • The Window and Help menus
  • Memory components
    • Poking memory
    • Pop-up menus and files
    • Hex editor
  • Logging
    • The Selection tab
    • The Table tab
    • The File tab
  • Application preferences
    • The Template tab
    • The Tools tab
    • The International tab
    • The Experimental tab
    • The command line
  • Project options
    • The Canvas tab
    • The Simulation tab
    • The Toolbar tab
    • The Mouse tab
  • Value propagation
    • Gate delays
    • Oscillation errors
    • Shortcomings
  • JAR libraries
    • Gray Code Incrementer
    • Library Class
    • Simple Gray Code Counter
    • Gray Code Counter
    • Guidelines
  • About the program
    • GNU General Public License
• Library Reference
  • Base library
    • Poke Tool
    • Edit Tool
    • Select Tool
    • Wiring Tool
    • Text Tool
    • Menu Tool
    • Splitter
    • Pin
    • Probe
    • Clock
    • Text
  • Gates library
    • Constant
    • NOT Gate
    • Buffer
    • AND/OR/NAND/NOR Gate
    • XOR/XNOR/Even/Odd Gate
    • Controlled Buffer/Inverter
  • Plexers library
    • Multiplexer
    • Demultiplexer
    • Decoder
    • Priority Encoder
    • Bit Selector
  • Arithmetic library
    • Adder
    • Subtractor
    • Multiplier
    • Divider
    • Negator
    • Comparator
    • Shifter
  • Memory library
    • D/T/J-K/S-R Flip-Flop
    • Register
    • Counter
    • Shift Register
    • Random
    • RAM
    • ROM
  • Input/Output library
    • Button
    • Joystick
    • Keyboard
    • LED
    • 7-Segment Display
    • Hex Digit Display
    • LED Matrix
    • TTY
  • Legacy library
    • Logisim 1.0 D/J-K Flip-Flop
    • Logisim 1.0 8-Bit Register

The explorer pane

Logisim organizes tools into libraries. They are displayed as folders in the explorer pane; to access a library's components, you have only to double-click the corresponding folder. Below, I have opened the Gates library and selected the NAND tool from it. You can see that Logisim now stands ready to add NAND gates into the circuit.

If you look through the choices in the Gates library, you'll notice that there was no need for us to develop a XOR circuit earlier: It's built into Logisim.

When you create a project, it automatically includes several libraries:

• Base: Tools that are integral to using Logisim.
• Gates: Components that perform simple logic functions.
• Plexers: More complex combinational components, like multiplexers and decoders.
• Arithmetic: Components that perform arithmetic.
• Memory: Components that remember data, like flip-flops, registers, and RAM.
• I/O: Components that exist for the purpose of interacting with the user.

Logisim allows you to add more libraries, too, using the Load Library submenu of the Project menu. You can see that Logisim has three categories of libraries.

• Built-in libraries are libraries that are distributed with Logisim. These are documented in the Library Reference.

• Logisim libraries are projects built within Logisim and saved to the disk as a Logisim project. You can develop a set of circuits in a single project (as described in the Subcircuits section of this guide) and then use that set of circuits as a library for other projects.

• JAR libraries are libraries that are developed in Java but not distributed with Logisim. You can download JAR libraries that others have written, or you can write your own as described in the JAR Libraries section of this guide. Developing a JAR library is much more difficult than developing a Logisim library, but the components can be much fancier, including things like attributes and interaction with the user. The built-in libraries (other than Base) were written using the same API as JAR libraries can use, so they aptly demonstrate the range of functionality that the JAR libraries can support.

  Some JAR libraries are distributed without any information about which Java class to start with. When loading such a JAR, Logisim will prompt you to type a class name. This class name should be provided by whoever distributed the JAR file to you.

To remove a library, choose Unload Library... from the Project menu. Logisim will prevent you from unloading libraries that contain components used in a circuit, that appear in the toolbar, or that are mapped to a mouse button.

Incidentally, a library technically contains tools, not components. Thus, in the Base library you'll find the Poke Tool (), the Edit Tool (), and other tools that don't correspond directly to individual components. Most libraries, though, contain only tools for adding individual components; all built-in libraries other than the Base library are like this.

Next: The attribute table.