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Activity 2.1.4 AOI Logic Implementation
Introduction
Would you pay $199 for a written specification for an MP3 player? Would you pay $299 for
the schematics for a cell phone? Of course not. You don’t pay for the specifications or the
schematics; you pay for the product itself.
You are not quite to the point where you can design an MP3 player or a cell phone, but you
can design AOI logic circuits. In this activity you will learn how to implement AOI logic circuits
from logic expressions. The logic expressions will be in either Sum-Of-Products (SOP) or
Product-Of-Sums (POS) form.
Equipment
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Your own sheet of paper for responses and planning, with your name, date, and
period, and using the name of this assignment as a title. You will submit a digitized
copy of your work to Canvas when you submit your screenshots, below.
Circuit Design Software (CDS)
Procedure
Let’s examine the process of implementing an AOI logic circuit by designing a circuit for the
relatively simple Sum-Of-Products (SOP) logic expression F1.
F1  A C  A B  A B C
1. Begin by creating a truth table that represents this logic expression. You can use the
process described in 2.1.3. You will use this truth table to confirm that your circuit in step
3 works by checking each set of inputs and confirming that the outputs match. (3E16)
2. On your own sheet of paper, draw an AOI circuit that implements the logic expression
F1, assuming that only “2-input” AND gates (74LS08N), “2-input” OR gates (74LS32N),
and inverters (74LS04N) are available. See our presentation for examples of how to draw
this circuit. You will digitize your hand drawn circuit, to be submitted in the PDF file to
Canvas, named as per our class file-naming conventions.
3. Using the CDS, enter and test the logic circuit that you designed in Step #2. Use SPDT
switches for the inputs A, B, & C (assigning keys to “SDF”), probes and a Hex Display for
the inputs, and a probe for the output F1. Verify that the circuit is working as expected.
Take a screenshot of the working circuit, to be submited in the PDF file to Canvas,
named as per our class file-naming conventions.
© 2020 Project Lead The Way, Inc.
Digital Electronics Activity 2.1.4 AOI Logic Implementation – Page 1
Though they are less frequently used, in later activities we will see that occasionally, logic
expression in the Product-Of-Sums (POS) form are easier to implement than SOP equations.
For practice let’s implement an AOI circuit for the logic expression F2.
F2  ( A  C )  ( A  B  C )
4. Again, create a truth table that represents this logic expression on your own sheet of
paper. You may need to consider each set of inputs in the expression to determine the
output. You will use this truth table to confirm that your circuit in step 6 works by checking
each set of inputs and confirming that the outputs match. (AD16)
5. On your own sheet of paper, draw an AOI circuit that implements the logic expression F2,
assuming that only “2-input” AND gates (74LS08N), “2-input OR” gates (74LS32N),
and inverters (74LS04N) are available. Draw this circuit on your own sheet of paper.
See our presentation for examples of how to draw this circuit. You will digitize your hand
drawn circuit, to be submitted in the PDF file to Canvas, named as per our class filenaming conventions.
6. Using the CDS, enter and test the logic circuit that you designed. Use SPDT switches for
the inputs A, B, & C (assigning keys to “SDF”), probes and a Hex Display for the inputs,
and a probe for the output F2. Verify that the circuit is working as expected. Take a
screenshot of the working circuit, a to be submited in the PDF file to Canvas,
named as per our class file-naming conventions.
7. Submit your SOP Truth Table, SOP Hand Drawn Circuit, SOP Screenshot, your POS
Truth Table, POS Hand Drawn Circuit, and POS Screenshot in a PDF file to Canvas,
naming the file as per our class file-naming conventions.
© 2020 Project Lead The Way, Inc.
Digital Electronics Activity 2.1.4 AOI Logic Implementation – Page 2