Multiplexer

A multiplexer is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n select lines, which are used to select which input line to send to the output.

Please design the entity as well as the test bench for a 4-to-1 multiplexer. For this multiplexer, please use the following to refer to the inputs/outputs of the circuit: I3, I2, I1, I0 as data inputs; S1 and S0 as selection inputs; and out0 as data output.

Your entity design is:

Your test bench design is:

In your test bench design, please enable each one of the 4 inputs at one time. For example enable I0 to go through the multiplexer first by letting S1 = ‘0' and S0 = ‘0'.

For this case, set I0 to be at "0" for 50ns, and then "1" for 50ns. After this, change S1, S0 values to let I1 (go through ‘0' and ‘1' each for 50ns), I2 (go through ‘0' and ‘1' each for 50ns), and I3 (go through ‘0' and ‘1' each for 50ns) pass the multiplexer correspondingly.

The result waveforms are:

Please select the signals to be simulated in the following order: S1, S0, I3, I2, I1, I0, Out0.