SmartSim

SmartSim is a digital logic circuit design and simulation package.

Features

Designing circuits using your own custom components.
Simulating circuits interactively, with the ability to explore inside custom components.
Creating logic timing diagrams from simulations.
Create circuits with loadable and saveable RAM/ROM.
Exporting your design or timing diagram to PNG, PDF, and SVG.
Plug-in components for expanding circuit capabilities.