https://sourceforge.net/projects/tkgateDescription: 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. For more information, check out the documentation. TkGate is free software provided with source code under the GPL (GNU General Public License).gold 25Nov2017, replaced dead link with pix from Sourceforge.
