CS2110 Project 1 - Digital Logic Solution

1 Introduction
2 Setup
The software you will be using for this project and all future circuit based assignments is called CircuitSim - an interactive circuit simulation package.
CircuitSim is a powerful simulation tool designed for educational use. This gives it the advantage of being a little more forgiving than some of the more commercial simulators. However, it still requires some time and effort to be able to use the program efficiently.
Please follow the instructions in the file ”CircuitSim Installation Guide.pdf” in Canvas, under ”Files > Course Software > CircuitSim” to install CircuitSim.
All .sim files should be opened in CircuitSim.
3 Part 1 — Introduction to CircuitSim
The first part of this project is designed to get you up to speed with CircuitSim. If you do not have CircuitSim downloaded and running, see the setup section of this document to get there.
3.1 Read Resources
Read through the following resources
• CircuitSim Wires Documentation https://ra4king.github.io/CircuitSim/docs/wires/
• Tutorial 0: My First Circuit https://ra4king.github.io/CircuitSim/tutorial/tut-1-beginner
3.2 Complete Tutorial 1
In the existing file tutorial1.sim and subcircuit Tutorial 1, complete the following tutorial. Do not rename the subcircuit or file. Be sure to label your two inputs a and b, and your output as c.
Complete Tutorial 1 https://ra4king.github.io/CircuitSim/tutorial/tut-2-xor
3.3 Complete Tutorial 2
In the existing file tutorial2.sim and subcircuit Tutorial 2, complete the following tutorial. Do not rename the file or subcircuit. Name the input in, and the output out.
Complete Tutorial 2 https://ra4king.github.io/CircuitSim/tutorial/tut-3-tunnels-splitters
4 Part 2 — ALU
Now that we have the basics down, we can move on to more complex circuits and logic. All computer processors have a very important component known as the Arithmetic Logic Unit (ALU). This component allows the computer to do, as the name suggests, arithmetic and logical operations. For this part, you’re going to build an ALU of your own, along with creating some of the gates.
For this part of the project you will:
1. Create the standard logic gates (NAND, NOR, NOT, AND, OR)
2. Create an 8-input multiplexer and an 8-output decoder
3. Create a 1-bit full adder
4. Create an 8-bit full adder using your 1-bit full adder
5. Use your 8-bit full adder and other components to construct an 8-bit ALU
When building these circuits, restrictions have been placed on what you can use. These restrictions are listed at the beginning of each section. Using anything not listed will result in heavy deductions. You also need to have everything in its correctly named sub-circuit. More information on the sub-circuits is given below.
Use tunnels where necessary to make your designs more readable, but do not overdo it! For gates, multiplexers, decoders, and adders you can often make clean circuits by placing your components strategically rather than using tunnels everywhere.
Throughout this assignment, do not change/delete any of the input/output pins (You can move them).
4.1 1-Bit Logic Gates
Allowed Components: Wiring Tab and Circuits Tab
All of the circuits are found in the gates.sim file.
For this part, you will create a transistor-level implementation of the NAND, NOT, NOR, AND, and OR logic gates.
Remember for this section that you are only allowed to use the components listed in the Wiring section, along with any of the logic gates you are implementing in CircuitSim. For example, once you implement the NOT gate you are free to use that subcircuit in implementing other logic gates. Implementing the gates in the order of the subcircuit tabs can be the easiest option.
All of the logic gates must be within their named sub-circuits.
4.2 Muxes
Allowed Components: Wiring Tab, Gates Tab, and Circuits Tab
All of the circuits are found in the muxes.sim file.
4.2.1 Decoder
The decoder you will be creating has a single 3-bit selection input (SEL), and eight 1-bit outputs (labeled A, B, C, ..., H). The decoder uses the SEL input to raise a specific output line. 000 should correspond to A, 001 should correspond to B, etc.
4.2.2 Multiplexer, commonly abbreviated as ”mux”
The multiplexer you will be creating has 8 1-bit inputs (labeled appropriately as A, B, C, ..., H), a single 3-bit selection input (SEL), and one 1-bit output (OUT). The multiplexer uses the SEL input to choose a specific input line for forwarding to the output. 000 should correspond to A, 001 should correspond to B, etc.
4.3 Adders
Allowed Components: Wiring Tab, Gates Tab, and Circuits Tab
All of the circuits are found in the alu.sim file. Throughout this assignment, you do not need to account for overflow.
4.3.1 1-Bit Adder
The full adder has three 1-bit inputs (A, B, and CIN), and two 1-bit outputs (SUM and COUT). The full adder adds A + B + CIN and places the sum in SUM and the carry-out in COUT.
For example:
A = 0, B = 1, CIN = 0 ==> SUM = 1, COUT = 0
A = 1, B = 0, CIN = 1 ==> SUM = 0, COUT = 1
Hint: Making a truth table of the inputs will help you.
4.3.2 8-Bit Adder
You should daisy-chain 8 of your 1-bit full adders together in order to make an 8-bit full adder.
This circuit should have two 8-bit inputs (A and B) for the numbers you’re adding, and one 1-bit input for CIN. The reason for the CIN has to do with using the adder for purposes other than adding the two inputs.
There should be one 8-bit output for SUM and one 1-bit output for COUT.
4.4 8-Bit ALU
Allowed Components: Wiring Tab, Gates Tab, Plexer Tab, and Circuits Tab
000 add [A + B]
001 sub [A - B]
010 min [min(A, B)]
011 mysteryFunction See below
100 mostSignificantOne See below
101 isMultipleOf32 [A % 32 == 0]
110 multiplyByNegative7 [A * -7]
111 isPositive [A > 0]
Remember, do NOT account for overflow. isMultipleof32 and isPositive should return either 00000000 for false or 00000001 for true.
mysteryFunction: For this operation, you will need to implement a circuit which calculates the result of the following formula for input A: wordsize −⌊log2A⌋− 1.
Note: For this function, the input can be treated as unsigned.
Edge Case: When A = 0, the output of this function should be equal to the wordsize.
Hint: Try applying this formula to the first 16 non-negative integers (0-15) using a wordsize of 4. Look for a pattern.
Examples:
A = 00011001 => return 00000011 (3)
A = 00000111 => return 00000101 (5)
mostSignificantOne: To elaborate, this operation should return the 8-bit representation of the value that is produced when all bits of A are cleared except for the most significant 1.
Examples:
A = 01100110 => return 01000000
A = 00001100 => return 00001000
Notice that mysteryFunction, mostSignificantOne, isMultipleof32, multiplyByNegative7, and isPositive only operate on the A input. They should NOT rely on B being a particular value.
This ALU has two 8-bit inputs (A and B) and one 3-bit input for OP, which is the op-code for the operation in the list above. It has one 8-bit output named OUT.
The provided autograder will check the op-codes according to the order listed above (add (000), sub (001), etc.) and thus it is important that the operations are in this exact order. If you ever need a constant value, use a constant pin (not an input pin). Failing to do so will interfere with the autograder.
As always, do not change/delete any of the input/output pins (You can move them).
5 Part 3 — Advanced Combinational Logic
All of the circuits are found in the project.sim file.
For this part of the assignment, you are tasked with creating a sum of products circuit such that its behavior matches the expected behavior outlined by the truth table found in the truthtable kmap.xlsx spreadsheet. In order to do so, you should use the techniques taught in class to create and reduce boolean expression (see 5.1 below).
As always, do not change/delete any of the input/output pins (You can move them).
5.1 Karnaugh Maps
While it is not a deliverable, making 2 K-maps and reducing boolean expressions will make this circuit significantly easier to design. To aid this, we have provided a template for both K-maps below and in the truthtable kmap.xlsx spreadsheet:
A B′C′ B′C BC BC′ A′ B′C′ B′C BC BC′
D′E′ D′E′
D′E D′E
DE DE
DE′ DE′
Note: The truthtable kmap.xlsx spreadsheet is NOT a deliverable. It only contains the truthtable that you need to use and sample K-Map templates.
5.2 Boolean Logic Details
For this part of the project, we are asking that you approach this problem in sum of products format.
This means that after your reductions using the K-maps, you should have something in the format
OUT = A′B + C
before attempting to build the circuit. Failure to do so can lead to complications in your circuit that prevent the reduction we are looking for.
5.3 Circuit Details
To prevent trivialization of this assignment, we have placed a few restrictions:
• All of this circuit should be contained in the project.sim file
• You should try to reduce the amount of AND and OR gates as much as possible.
Hint: The K-maps do this for you!
6 Autograder
To run the autograder, run
java -jar project1-tester-1.0.jar
at a command prompt in the same directory as all your .sim files. This is the same autograder that Gradescope uses, but is much easier and faster to use. The autograder should be run from the terminal.
7 Deliverables
Please submit the follow files:
1. tutorial1.sim
2. tutorial2.sim
3. gates.sim NOT, NAND, NOR, AND, OR
4. muxes.sim Decoder, MUX
5. alu.sim 1-Bit Adder, 8-Bit Adder, 8-Bit ALU
6. project.sim Advanced Combinational Logic
to Gradescope under the assignment “Project 1 - Digital Logic”.
8 Rules and Regulations
8.1 General Rules
2. Please read the assignment in its entirety before asking questions.
4. If you find any problems with the assignment, it would be greatly appreciated if you reported them tothe author (which can be found at the top of the assignment). Announcements will be posted if the assignment changes.
8.2 Submission Conventions
1. In order to submit your assignment, submit the files individually to the Gradescope assignment.
2. Do not submit links to files. The autograder does not understand it, and we will not manually gradeassignments submitted this way as it is easy to change the files after the submission period ends.
8.3 Submission Guidelines
2. You are also responsible for ensuring that what you turned in is what you meant to turn in. Aftersubmitting you should be sure to download your submission into a brand new folder and test if it works. No excuses if you submit the wrong files, what you turn in is what we grade. In addition, your assignment must be turned in via Gradescope. Under no circumstances whatsoever we will accept any email submission of an assignment. Note: if you were granted an extension you will still turn in the assignment over Gradescope.
3. Projects turned in late receive partial credit within the first 48 hours, as defined in the syllabus.Between 0 and 24 hours late, you can receive a maximum score of 70%. Between 24 and 48 hours late, you can receive a maximum score of 50%. We will not accept projects turned in over 48 hours late.
8.4 Is collaboration allowed?
From the syllabus:
8.5 Syllabus Excerpt on Academic Misconduct
The goal of all assignments in CS 2110 is for you to learn. Learning requires thought and hard work. Copying answers thus prevents learning. More importantly, it gives an unfair advantage over students who do the work and follow the rules.
3. Using code from GitHub, via Googling, from Stack Overflow, etc., is Academic Misconduct (HonorCode: Academic Misconduct includes “submission of material that is wholly or substantially identical to that created or published by another person or persons”).
4. Publishing your assignments on public repositories, github, etc, that is accessible to other students isunauthorized collaboration and thus Academic Misconduct.
5. Suspected Academic Misconduct will be reported to the Division of Student Life Office of StudentIntegrity. It will be prosecuted to the full extent of Institute policies.
6. Students suspected of Academic Misconduct are informed at the end of the semester. Suspects receive an Incomplete final grade until the issue is resolved.
7. We use accepted forensic techniques to determine whether there is copying of a coding assignment.
8. Submitting an assignment with code or text from an AI assistant (e.g., ChatGPT) is academic misconduct.
Anything you did not write in your assignment will be treated as an academic misconduct case. If you are unsure where the line is between collaborating with AI and copying AI, we recommend the following heuristics:
Heuristic 1: Never hit “Copy” within your conversation with an AI assistant. You can copy your own work into your own conversation, but do not copy anything from the conversation back into your assignment. Instead, use your interaction with the AI assistant as a learning experience, then let your assignment reflect your improved understanding.
Heuristic 2: Do not have your assignment and the AI agent open at the same time. Similar to the above, use your conversation with the AI as a learning experience, then close the interaction down, open your assignment, and let your assignment reflect your revised knowledge. This heuristic includes avoiding using AI directly integrated into your composition environment: just as you should not let a classmate write content or code directly into your submission, so also you should avoid using tools that directly add content to your submission.
Deviating from these heuristics does not automatically qualify as academic misconduct; however, following these heuristics essentially guarantees your collaboration will not cross the line into misconduct.