TkGate is a event driven digital circuit simulator with a tcl/tk-based graphical editor. TkGate supports a wide range of primitive circuit elements as well as user-defined modules for hierarchical design. The distribution comes with a number of tutorial and example circuits which can be loaded through the "Help" menu. The example circuits include a simple CPU, programmed to run the Animals game.

• Graphical circuit design
  
  
  
  • Hierarchical design through user defined modules.
    
  • Easy to use point-and-click user interface.
    
  • Create hyperlinks to move about in circuit or load other files.
    
  • Multi-lingual interface (Catalan, English, French, German, Japanese, Spanish, Welsh)
    
  • Verilog-like save file format.
    
  
  
  
• Logic simulation
  
  
  
  • Control through the GUI or through script files.
    
  • Suitable for simulation at transistor, gate or register transfer level.
    
  • Six valued logic model including 0, 1, floating, unknown, "low" and "high".
    
  • Support for custom delay models.
    
  • Graphical display of simulation results.
    
  • Breakpoints, single-step and clock-step simulator control.
    
  • Static critical path analysis.
    
  
  
  
• Primitive circuit elements include:
  
  
  
  • Basic gates (AND, OR, etc.)
    
  • Switch-level NMOS and PMOS transistors
    
  • Tristate buffers
    
  • Alu components (Adders, shifters, multipliers)
    
  • Memory elements (Registers, RAMs, ROMs)
    
  • An interactive "tty" element allows design of circuits that can interact with the user.
    
  
  
  
• Support tools include a microcode/macrocode compiler to assist in
  creating large projects such as microprocessor designs.