# Solve 8:1 Mux Simulation with C Program

• TimFortin
In summary: Good luck!In summary, the question is about creating a C program to simulate an 8:1 multiplexer using only certain logical operators. The solution involves understanding how a multiplexer works and using a boolean expression to assign the control and source inputs to the output. It is also suggested to consider using HDL instead of C for this task.
TimFortin

## Homework Statement

Hello all, this is my first post here although I've used this site for referencing several times. My question is regarding an 8:1 multiplexer. I need to write a c program using just &&, || and ! to simulate each gate of an 8:1 mux. We have 3 control inputs and 8 source inputs and need to have just a single output. I don't understand what the need of the 8 source inputs is when you can get the correct output by using a boolean expression on the three control inputs. So to simplify my question, how do i turn the 11 (8 source + 3 control) inputs into 1 output.
Thanks for looking

## Homework Equations

ans = (!a && !b) + (!a &&b &&c) + (a && !b && !c);
This produces correct answer but does not use the source inputs at all

## The Attempt at a Solution

My attemp at a solution is the equation i posted above, as well as trying to use 2 4:1 muxes and a 2:1 mux but i can't seem to make any sense of it.

TimFortin said:

## Homework Statement

Hello all, this is my first post here although I've used this site for referencing several times. My question is regarding an 8:1 multiplexer. I need to write a c program using just &&, || and ! to simulate each gate of an 8:1 mux. We have 3 control inputs and 8 source inputs and need to have just a single output. I don't understand what the need of the 8 source inputs is when you can get the correct output by using a boolean expression on the three control inputs. So to simplify my question, how do i turn the 11 (8 source + 3 control) inputs into 1 output.
Thanks for looking

## Homework Equations

ans = (!a && !b) + (!a &&b &&c) + (a && !b && !c);
This produces correct answer but does not use the source inputs at all

## The Attempt at a Solution

My attemp at a solution is the equation i posted above, as well as trying to use 2 4:1 muxes and a 2:1 mux but i can't seem to make any sense of it.

>The first thing I want to ask is that do you know how a multiplexer works?
This is because the code that you have pasted shows that you do not fully understand how a multiplexer works.

>if you use "s0,s1,s2" as the control inputs and "a0,a1,a2,a3,a4,a5,a6,a7" as the input pins while "ans" is ur answer then the C program must assign these inputs and switches to answer in the following manner...

ans=(!s0 && !s1 && !s2 && a0 )||(s0 && !s1 && !s2 && a1 )||(!s0 && s1 && !s2 && a2 )||(s0 && s1 && !s2 && a3 )||.... till all possible values of s0,s1,s2 have been utilized.

>If you are inclined to use two 4:1 muxes and one 2:1 then you can make them the same way the 8:1 mux is made. If you still don't understand then PM me or post here.

>If you are not forced to make this program in C then i would suggest that you program it in HDL(hardware descriptive languages) like Verilog and VHDL which are meant for hardware design and verification and have nearly the same syntax like C.

I hope your problem is solved.

I would approach this problem by first understanding the purpose and function of a multiplexer. A multiplexer is a device that selects one of several input signals and forwards it to a single output line. In this case, we are dealing with an 8:1 multiplexer, which means it has 8 source inputs and 3 control inputs.

The first step would be to understand how the 8 source inputs and 3 control inputs are connected to the output. This can be done by drawing a truth table, which shows all the possible combinations of inputs and their corresponding outputs. From the given equation, it seems that the output is a function of the 3 control inputs only, but we need to make sure that it is indeed the case.

Next, I would suggest breaking down the problem into smaller parts. For example, you can start by simulating a 2:1 multiplexer using the given boolean expressions and then move on to a 4:1 multiplexer. This will help in understanding the logic behind the multiplexer and how the inputs are being selected.

In terms of using a C program, it would be helpful to first declare variables for the 8 source inputs and 3 control inputs and then use if-else statements to simulate each gate of the 8:1 multiplexer. You can also use loops to iterate through the different combinations of inputs and test the output.

Overall, the key to solving this problem is to have a clear understanding of the purpose and function of a multiplexer and to break down the problem into smaller parts to make it more manageable.

## 1. How do I write a C program for simulating a 8:1 Mux?

To write a C program for simulating a 8:1 Mux, you will need to first understand the structure and functionality of a Mux. Then, you can use conditional statements, loops, and logic to create a program that simulates the behavior of a 8:1 Mux. It is also important to thoroughly test and debug your code to ensure accuracy.

## 2. What is the purpose of a 8:1 Mux?

A 8:1 Mux, or 8-to-1 Multiplexer, is a digital logic circuit that selects one of 8 input signals and passes it to a single output based on a selection signal. It is commonly used in computer systems to select between multiple data sources and control signals.

## 3. What are the inputs and outputs of a 8:1 Mux?

The inputs of a 8:1 Mux are 8 data signals and a selection signal, while the output is a single data signal. The selection signal determines which of the 8 inputs will be passed to the output.

## 4. How can I test my 8:1 Mux simulation program?

To test your 8:1 Mux simulation program, you can create different input combinations and check if the output matches the expected result. You can also use simulation tools or test benches to simulate different scenarios and verify the functionality of your program.

## 5. Are there any alternative methods for simulating a 8:1 Mux?

Yes, there are alternative methods for simulating a 8:1 Mux such as using a hardware description language like Verilog or VHDL. These languages allow for a more efficient and accurate simulation of digital logic circuits. However, using a C program can also be a viable option depending on the complexity of the circuit and the programmer's expertise.

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