Re: Please Help me Somebody with DEMUX Gate

Posted by WBahn on May 20, 2019; 7:41pm
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/Please-Help-me-Somebody-with-DEMUX-Gate-tp4033175p4033184.html

Saying that you used a particular Mux part from the Multisim library of parts is not the same as knowing how to implement a multiplexer.

Have you implemented the Hack hardware in the Nand2Tetris HDL and gotten it to work? If so, then just implement the DeMux in Multisim using the same design strategy. Build your parts up the same way, starting with just two-input Nand gates.

If you haven't, then it might be a good idea to take a step back and do so.

If you aren't willing to do that, then start with a 1-bit, 2-way demultiplexer. You have two inputs (data and select) and two outputs (channel1 and channel2). What is the truth table for channel1? What circuit will implement that truth table? Now do the same for channel2. You're done.

Now see how you might implement a 1-bit, 4-way demux. There are a couple of fairly obvious routes you might choose. Try seeing if you can do one that is based on using your 1-bit, 2-way multplexers.

Now combined sixteen of those to make a 16-bit 4-way demultiplexer.