Easy- and fun-to-use schematic-driven logic simulator is now freeware!Have you seen the MultiMedia Logic Simulator (MMLogic) from Softronics Inc? If not, you are in for a treat, because this incredibly easy-to-use tool is now available for Immediate Download as Freeware!
This really is an ultra-cool application. First of all it has a schematic front end that allows you to select switches, logic gates, registers, displays, etc. from a pallet and place them in a schematic window. Then you wire these elements together. Finally, you say "simulate", and then you can click the switches and see the corresponding actions and events take place on the screen in front of you.
The MMLogic graphical user interface.
The reason this is currently of particular interest to me is due to the "Black Box Brain Boggler" I posed in my "Logically Speaking" column in the May 8th issue of EE Times. Just to refresh your memory, we have a black box with three inputs A, B, and C. It also has three outputs called not-A, not-B, and not-C. Each of these outputs is the logical inversion of its corresponding input; that is, if A = 0 then not-A = 1, and vice versa.
Obviously, if we had access to three NOT gates, then the solution would be simple, but we have only TWO NOT gates. Now, here's the problem, in my article I mistakenly said that we could also use as many AND, OR, and XOR gates as we wish. In fact we have only AND and OR gates, but no XOR gates.
For a long time I doubted it could be done, but I have now seen several really cunning solutions. In fact, this weekend I wrote them up and presented them all as a How To Article on Programmable Logic DesignLine.
For your delectation and delight, the guy who created MMLogic – George Mills – got interested in this, so he created a simulation of the winning solution. You can download this solution as a ZIP file by Clicking Here. All you have to do is unZIP it, use the File > Open command in MMLogic to load this circuit, then the Simulate > Run to start the simulator, and then click the switches representing the A, B, and C inputs.
Furthermore, at the end of the above article, I mention a possible alternative approach using a ring oscillator, multiplexer, and so forth. If I have enough time, I'm going to simulate this little rapscallion using MMLogic. In the meantime, why don’t you download a copy and try playing with it yourself? (Hint #1: When you run MMLogic, you can use the File Open command to access a variety of pre-created examples that you'll find in the "C:/Program Files/Softronics/Multimedia Logic/Examples" folder. Hint #2: Use the "Toggle Pallet" icon – the one that looks like two logic gates – on the tool bar to access the pallet of logic gates and devices you can play with.)
Questions? Comments? Feel free to email me – Clive "Max" Maxfield – at firstname.lastname@example.org). And, of course, if you haven't already done so, don't forget to Sign Up for our weekly Programmable Logic DesignLine Newsletter.