Fizzim is a FREE, open-source GUI-based FSM design tool. The GUI is written
in java for portability. The backend code generation is written in perl for
portability and ease of modification.


  • Runs on Windows, Linux, Apple, anything with java.
  • Familiar Windows look-and-feel.
  • Visibility (on/off/only-non-default) and color control on data and comment fields.
  • Multiple pages for complex state machines.
  • “Output to clipboard” makes it easy to pull the state diagram into your documentation.


  • Verilog/SystemVerilog/VHDL code generation based on recommendations from experts in the field.
  • Output code has “hand-coded” look-and-feel (no tasks, functions, etc).
  • Switch between highly encoded or onehot output without changing the source.
  • Registered outputs can be specified to be included as state bits, or pulled out as independent flops.
  • Mealy and Moore outputs available.
  • Transition priority available.
  • Automatic grey coding available.
  • Code and/or comments can be inserted at strategic places in the output – no need to “perl” the output to add your copyright or `include