![\"The](\"https:\/\/digilent.com\/blog\/wp-content\/uploads\/2014\/11\/Mux-e1416515189478.png\")
<\/a>The block diagram allows users to design large designs using a mux without having to worry about the logic inside of it. All they have to worry about is what it does. So what does it do?<\/p>\n
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The easiest way to think about a mux is that it is an input selector. Based on the select code you apply so the S inputs, it will connect only one input to the output. For a more formal definition, I’ve presented a truth table. A truth table shows all the possible outputs of a circuit for every possible combination of inputs.<\/p>\n You can also think of a mux as a switchboard. You are the output Y and the operator is the mux. Depending on the extension (S inputs) you give the operator, you will be connected to a different person (I inputs).<\/p>\n <\/p>\n For those with a coding background it may be better understood in code. Muxes are built off of case statements. In Verilog, a mux would look like this:<\/p>\n Now what is a demux? You can think of a demux as sort of the opposite of a mux. Instead of routing one of four inputs to 1 output, it takes one\u00a0input and routes it to one of four outputs. Here is the block diagram of a demux.<\/p>\n The signal EN is the input that you are trying to pass, and I0 and I1 create the select code for the output that you want to pass it to. If you want to pass a 1 to Y1. Then you need to hold EN high at a 1 and pass a 0 to I1 and a 1 to I0. In binary 01 is equivalent to 1, so\u00a0if you want to\u00a0select an output, pass the binary value to the I inputs.<\/p>\n <\/p>\n To clarify, here is the truth table for a demux:<\/p>\n If you would like to see a mux in action you can visit\u00a0learn.blog.digilentinc.com<\/a> and try out the\u00a0Multiplexer Guessing Game<\/a>\u00a0(using the Uno32) and\u00a0\u00a0the simple communication system<\/a>\u00a0(using FPGA) projects.<\/p>\n <\/p>\n <\/p>\n<\/a><\/a><\/a><\/a>