CMPE12, Spring 2012, Section 01: Lab 1: Intro to Logic with Multimedia Logic©

Administrative Issues:

  • Please make sure you are attending the correct lab section
  • Please make sure you have a UCSC account because you will need it to submit your lab assignments.
  • No partners allowed on this lab, it is to be done individually by each student, though feel free to discuss things at a high level.

Lab Objectives:

In this first lab, you will learn how to use the Multimedia Logic application in Windows to do schematic entry and simulation. MML is a free schematic entry and simulation tool. If you would like to get the tool for home (you still have to come to lab though) here is a link to the application.  You will use this program to build some simple circuits to give you a better intuition on how logic works.  You are expected to finish part A of this lab during the first lab section and the remaining parts during the second lab section.   Feel free to tart the later sections, though you might find them difficult.

Lab TA/tutors: Go over these topics

Your lab TA/tutor will cover the following topics in the first part of the lab.

  • Introductions
  • When labs are due
  • What's required when submitting a lab: Submitting the lab files and a detailed lab report. To submit your work, you need a UNIX account on the UCSC server. If you do not have one, talk to your tutor.
    • How to use sum of products to go from a 3-input, 1-output truth table to logic gates
  • Transfer your files to the UCSC server.
    • If you are in the BE109 or other IT lab, you can just drag and drop your files into your home directory (labeled X:).
    • Otherwise, you will need to FTP your files over. Use SFTP or a similar secure FTP program to transfer files. Open a connection to unix.ic.ucsc.edu with your username and password, and place the desired files into the desired directory on the UCSC server.
  • Connect to the UCSC server via SSH. Open a connection to with your username and password.unix.ic.ucsc.edu
  • Go into the  directory which has your files. Use cd directoryname to change directories.
  • Type the submit command:
                                                  submit cmpe012-tl.s12 labn_tutornameSectionNumber      files...,
  • where n is the number of the lab (this is lab1) and tutorname is the first name (all lowercase) of your tutor.

Lab1 Preparation:

  1. Read through this Lab1 assignment.
  2. Read the textbook chapter 3 up to section 3.4.
  3. Review the lecture notes on Digital Logic.

 

Transferring your files to the UCSC server:

If you are in the BE109 or other IT lab, you can just drag and drop your files into your home directory (labeled X:).  Otherwise, you will need to FTP your files over. Use SFTP or a similar secure FTP program to transfer files.  Open a connection to unix.ic.ucsc.edu with your username and password (same one you use to access your email account), and place the desired files into the target directory on the UCSC server.

Schematic comments Requirement:

  • Please put minimal block comments at the top of all schematics including your name and UCSC email address. You should also include more information such as Due Date, Lab number (Lab1), lab title, your section and TA/tutor.
  • Please comment your schematics neatly and succinctly. That is label the various input and output.

Part A: Warm-Up

Do the tutorial for Multimedia Logic (Help->Tutorial).  If the help->tutorial doesn't work. Go to youtube:

http://www.youtube.com/watch?v=hJq2gECXYWc&noredirect=1

This simply tutorial will walk you through building and simulating a simple circuit, save the result file as Lab1_tutorial.lgi.  Use Text tool to put the required comments on your schematic. 

Now, experiment with the logic gates by showing De Morgan's Laws in action. Save the resulting schematic as lab1_demorgans.lgi and submit it when you are done. We will have not actually have covered this material in class yet, but it is fun to just jump right in and starting doing things.  We will catch up quickly in class, trust that!

    1. Connect two switches to an AND gate. Connect the output of the AND gate to an LED. See what happens on the output when you change the inputs. Figure 1 shows how to add a switch from the palette.   

        

Figure 1: Adding a switch from the palette

  1. Now, add an inverter between the switch and the AND gate for each input. Refer to Figure 2.

 
Figure 2: AND gate with inverted inputs

  1. Connect the same two inputs to an OR gate and corresponding LED. Change the OR gate to a NOR gate: Right-click on the OR gate, select Properties, and choose "Invert Output (NOR)." Refer to Figure 3.

 
Figure 3: Inverting the outputs for a two-input OR gate to create a NOR gate

  1. Demonstrate De Morgan's Laws by running the circuit simulation and seeing that the two LEDs show the same output.

Part B: Sum of Products

This part is pretty simple if you wait till after we cover this in class on Tuesday evening.  Design two separate pieces of logic (all on one schematic) that implement the following truth table.  The first implementation can use AND and OR gates, the second can use ONLY NAND gates.  Do not try and minimize this logic. How many transistors does each implementation take? 

IN[2] IN[1] IN[0] Output
0 0 0 1
0 0 1 1
0 1 0 0
0 1 1 1
1 0 0 0
1 0 1 0
1 1 0 0
1 1 1 0

Things to note for Part B:

  • To create a NAND gate select the AND gate, place it in your schematic, then right click on it and select and check the box that says Invert Output(NAND) properties
  • Connect the inputs to the Switch tools and the output to an LED to verify your circuits work correctly; you can use the same inputs for both circuits but will need separate output LEDs.
  • As in part A put correct comments in your schematic.

 

Part C: Logic Optimization

Take your Sum of Product (SoP) expression from part B and use Boolean algebra to minimize it.  Draw the final circuit on a new schematic and discuss the minimization steps you did in the write up.

Part D: Guessing Game

Now you will create a fun guessing game in logic! Create a design that allows the user to play "guess the number", where the secret number is between 0 and 3.  Here are the steps you to follow:

  • Use the random number generator circuit element (see Figure 4). You only need to connect two of the outputs (any two will do), the outputs are the pins on the right side of the box.
  • Use a push-button switch to drive the random number generatiov. Connect the switch to "C+".
  • Use two switches for user input, this will be the guess.
  • Use combinational logic to test for equality; basically, is the output of the random number the same as that of the switches? Hint: Think logic AND.
  • Use an LED to indicate whether the user's guess was correct or not.

 
Figure 4: Random number element

Lab write-up requirements

In the lab write-up, we will be looking for the following things. The lab report is worth 50 points. We do not break down the point values; instead, we will assess the lab report as a whole while looking for the following content in the report.

  • The typical things a lab report should have. Read more about lab reports before submitting yours.
  • Discuss the original design. How did you get to the logic design from the truth table?
  • How many transistors in the original design from part B?
  • Discussion the changes you made to your design.
  • How many transistors in the improved design from part B?
  • Why do AND and OR gates have more transistors than NAND and NOR?
  • Discuss how you reduced the circuit in part B to the final circuit in part C.  How many transistors in the final circuit?
  • Make some sort of guess on how that random number generator works?  How can things be really random in a computer with logic gates being so, well, logical.

The tutors will go over the basics of this lab with you and will help you out as needed.  We will spend more time in lecture going over circuits.  It is just more fun to dive right in though and start playing with logic then sitting in class trying to stay awake.

Collaboration:

You are allowed to discuss this lab with your lab partner  and other students but are expected to do your own work.  We will always have lab partners.

Files to Submit:

  • Lab1A_tutorial.lgi
  • Lab1A_demorgans.lgi
  • Lab1B.lgi
  • Lab1C.lgi
  • Lab1D.lgi
  • Lab1_report.txt

Process to submit the files:

  • Connect to the UCSC server via SSH.  Open a connection to with your      username and password.unix.ic.ucsc.edu
  • Go into the directory which has your files.  Use cd directoryname to change      directories.
  • Type the submit command:

submit labn-tutornamefiles... where # is your the section number (1-6) and n=lab number.

Please ask the TA/tutor to double check your submission if you are worried about doing it correctly.

Check-off:

For this lab, as with most labs, you will need to demonstrate your lab when it is finished to the TA or tutor and get it signed off.  You will also need to submit your lab files using the UNIX machines provided by ITS. 

Grading template:

There are 2 parts to each lab grade, the work done such as creating a circuit or program, and the write up.  For this lab the write up is worth 50 points.  The circuits are worth 50 points.  Here is the break down for the circuits, which you will get signed off by a tutor/TA:

Did you...?

___ (5 pts) Have the schematics labeled (name, lab #, title, date, etc)?

___ (5 pts) Part A: Do the simple tutorial?

___ (5 pts) Part A: Correctly implement the logic for DeMorgans?

___ (10 pts) Part B: Correctly implement the logic with AND/OR gates?

___ (5 pts) Part B: Correctly implement the logic with only NAND gates?

___ (5 pts) Part B: Correctly count the number of transistors in each implementation?

___ (5 pts) Part C: Correct reduce the circuit down?

___ (10 pts) Part D: Does the game work?


Happy Designing!!