DE Unit 5: Displays

Multiplexers & Demultiplexers with Segmented Displays

DISPLAYS OVERVIEW

Welcome to the 5th unit of Digital Electronics! By now we understand the basics of the circuit design process, it’s just time to add new tools to what we know. In this unit, we’ll get tools that let us display numbers and letters more easily, combine (or uncombine) digital signals, and perform basic mathematics using only digital circuits.  As we progress, we’ll be thinking about the following questions:

  • How can a digital (on/off) circuit display things like numbers and letters?
  • How can we combine lots of individual signals into one larger digital signal?
  • How could we break apart a large digital signal into multiple smaller ones?
  • How do binary numbers work with negatives?
  • How do we add binary numbers, and how can that be done with a digital circuit?

These questions will keep us moving forward through the unit as we learn more ways that circuits can be made to do complex things. For this unit, you’ll work through three main stages:

  1. STEP 1: Learn how to use 7-segment displays in your digital circuits
  2. STEP 2: Learn about multiplexers and demultiplexers
  3. STEP 3: Binary math through digital logic

At the end of the unit, you will have learned about new integrated circuit chips (IC chips) that can help make more complex digital signals. You’ll also learn how to make displays of numbers and letters, and how to build a basic calculator. Together, the circuits you build in this unit will help demonstrate the use of many new digital electronics tools.

PART 1: 7-SEGMENT DISPLAYS

(40 pts) About 2 days

The first part of our next unit is all about 7-segment displays.  A 7-segment display will let you turn a 4-bit binary signal (like 1001) into a digit display like on a digital clock.  These displays are common in digital circuits, and here we get to learn how to use them!

PART 2: MUX/DEMUX

(40 pts) About 3 days

Sometimes we need to take multiple small signals and combine them into one complex signal: this requires a Multiplexer (MUX).  In cases where we need to take a complex signal and break it apart into simpler ones, we’ll use a Demultiplexer (DEMUX). This part of the unit explains these tools and how they work!

PART 3: BINARY MATH

(40 pts) About 3 days

In addition to being able to display information, we eventually need circuits to be able to combine information and even do some basic math. Using the logic gates XOR and XNOR, we’re able to create circuits that can add binary numbers. Then, we can combine these circuits with our mutliplexers and seven segment displays to make a basic calculator!

Part 1: 7-Segment Displays

Learn how to implement 7-segment displays in your digital circuits

7-Segment Display Map

As we start our next unit, we’ll turn our attention to some new digital components.  Here, we get to look at 7-Segment Displays and their Drivers.  A 7-Segment Display takes seven inputs to turn on/off individual segments in what is basically a complicated LED.  This system lets us show numbers and some letters as we build circuits that we want to be able to read. The Driver for these displays can take a 4-bit input (like the binary number 1100), and converts it into the seven on/off signals for the 7-Segment Display.  In this part of the unit, you get to investigate how these work together to give us more functionality in our digital designs.

GRADING & PROCESS

Watch the Displays Overview, 7-Segment Displays, and 7-Segment Display Driver videos and take a full page of notes.

 Complete the investigation 7-Segment Displays Assignment.

Create the given circuits in Multisim and by breadboarding to learn how the displays work and to answer the reflection questions.

 Have Mr. Benshoof approve your notes and completed Assignments.

Displays Overview

7-Segment Displays

7-Segment Display Driver

What’s Due In Part 1: 7-Segment Displays

  • 7-Segment Notes
  • 7-Segment Assignment
  • 7-Segment Displays
  • Mr. Benshoof’s Approval

Here’s what’s due in Part 1: 7-Segment Displays

  1. Good notes on 7-Segment Displays & Drivers
  2. Complete the 7-Segment Display Activity
  3. Create the 7-Segment Displays in Multisim and Breadboarding
  4.  Have Mr. Benshoof approve your notes and assignment.

Part 2: MUX/DEMUX

Learning to apply multiplexers and demultiplexers

MUX/DEMUX Overview

 

Often we have systems with a different number of inputs and outputs to work together correctly.  One example is when we have a 4-bit binary input for a 7-seven segment display, but need the 7 individual inputs to make it work. In cases like this, we can use multiplexers & demultiplexers to change those digital signals and either combine them or break them apart.  In this part of our unit, we’ll learn how to use multiplexers to combine multiple signals into just one. We’ll also learn how to use demultiplexers to take one large signal and break it apart into smaller ones.  

GRADING & PROCESS

 Take a full page of careful notes on multiplexers and demultiplexers while watching our four presentations.

 Use Multisim and your breadboard to build the circuits required for the Multiplexer/Demultiplexer Assignment.

 Complete the Multiplexer/Demultiplexer Assignment.

 Have Mr. Benshoof check-off your notes, assignments, and circuits.

Multiplexed & Demultiplexed Signals

 

Multiplexers

Demultiplexers

What’s Due In Part 2: MUX/DEMUX Overview

  • MUX/DEMUX Notes
  • MUX/DEMUX Circuits
  • MUX/DEMUX Assignment
  • Benshoof’s Check-off

Here’s what’s due in Part 2: MUX/DEMUX Overview

  1. Take a full page of notes on multiplexers and demultiplexers.
  2. Simulate and build the circuits needed for the MUX/DEMUX Assignment
  3. Complete the Multiplexer/Demultiplexer Assignment.
  4. Have Mr. Benshoof check-off your notes, assignments, and circuits.

Part 3: Binary Math

Learn how negative numbers are represented in binary, and how to make a binary adding circuit

Binary Math Overview

The last part of our unit will ask us to tackle some tough mathematics and learn two new logic gates. The new math we’ll need to learn is called the “2’s Complement”, and it’s a way that binary numbers can represent negative numbers. This is particularly useful if we want to use an adding machine to do subtraction. After that, we’ll learn about the new logic gates XOR and XNOR, and then look at a circuit that can add binary numbers. As usual, we’ll simulate the circuit in Multisim and breadboard it so we can investigate how it works!

GRADING & PROCESS

 Take a full page of detailed notes on the 2’s Complement process. Two presentations are provided to give you multiple explanations of how this works.

 Complete the 2’s Complement Assignment.

 Take another page of notes, this time on the XOR and XNOR gates as well as the logic behind the Binary Adders circuit.

 Use Multisim to simulate the binary adders shown in the assignment.

 Complete the Binary Adders Assignment using your circuits.

 Have Mr. Benshoof check-off your notes, assignments, and circuits.

2’s Complement Arithmetic

2’s Complement Again

XOR, XNOR & Binary Adders

What’s Due In Part 3: Fireplace Control

  • 2’s Complement Notes
  • 2’s Complement Assignment
  • XOR/XNOR/Adder Notes
  • Multisim Binary Adders
  • Binary Adders Assignment
  • Mr. Benshoof’s Check-Off

Here’s what’s due in Part 3: Fireplace Control

  1. Take a full page of notes on the 2’s Complement.
  2.  Complete the 2’s Complement Assignment.
  3.  Take a full page of notes on XOR, XNOR, and Binary Adders
  4. Multisim the binary adders.
  5.  Complete the Binary Adders Assignment using your circuits.
  6. Have Mr. Benshoof check-off your notes, assignments, and simulated circuits.

Double Check: Unit Expectations

Check what you need to have completed by the unit deadline

The purpose of this unit is to give an introduction to a wide range of new digital electronics tools: 7-segment displays, display drivers, multiplexers, demultiplexers, XOR gates, and XNOR gates. These tools are demonstrated in a variety of ways including the building of a basic addition/subtraction calculator. You should have good notes on each of these concepts so that you can apply them in your future work.

Engineering Notebook:

(Part 1) You should have taken a full page of notes on Simplifying & K-Mapping.

(Part 2) You should have taken a full page of notes on both NAND Gates and on NOR Gates.

(Part 3) You should have made a Truth Table, logic expression, and simplified the expression for the Fireplace Control Circuit problem in your engineering notebook.

(Part 3) You should have drawn out your AOI/NAND/NOR circuit in your notebook before simulating.

Building & Making:

(Part 1) You should have completed the investigation 7-Segment Displays Assignment.

 (Part 1) You should have simulated the 7-Segment Display Circuits in Multisim.

(Part 2) You should have built the Multiplexer/Demultiplexer circuits in Multisim and on the breadboard.

 (Part 2) You should have completed the Multiplexer/Demultiplexer Assignment.

 (Part 3) You should have completed the 2’s Complement Assignment.

(Part 3) You should have built your Binary Adders in Multisim and confirmed that it works properly.

 (Part 3) You should have completed the Binary Adders Assignment.

Checkpoints & Quizzes:

(Part 1) Benshoof should have checked-off your notes and completed assignments.

(Part 2) Benshoof should have checked-off your notes, assignments, and circuits.

(Part 3) Benshoof should have confirmed your notes, assignments, and circuits.