Logical operators (and, or, xor, not, nand, nor) in VHDL - Mini Project: Build & Apply

Logical Operators in VHDL

📖 Scenario: You are designing a simple digital circuit in VHDL that uses basic logical operators to combine input signals.

🎯 Goal: Build a VHDL architecture that defines signals and uses and, or, xor, not, nand, and nor operators to produce output signals.

📋 What You'll Learn

Create signals with exact names and values

Define a configuration signal

Use all six logical operators in signal assignments

Print the final output signals using a process and report statements

💡 Why This Matters

🌍 Real World

Logical operators are the foundation of digital circuits used in computers, phones, and many electronic devices.

💼 Career

Understanding logical operators in VHDL is essential for hardware engineers and FPGA developers who design digital systems.

1

DATA SETUP: Define input signals

Create two signals called A and B of type std_logic and set A to '1' and B to '0'.

VHDL

-- Declare signals A and B of type std_logic
-- Your code here

Need a hint?

Use signal keyword and assign '1' or '0' to each signal.

2

CONFIGURATION: Define output signals

Create six signals called out_and, out_or, out_xor, out_not, out_nand, and out_nor of type std_logic.

VHDL

signal A : std_logic := '1';
signal B : std_logic := '0';
-- Declare output signals of type std_logic
-- Your code here

Need a hint?

Declare each output signal with the exact name and type std_logic.

3

CORE LOGIC: Assign output signals using logical operators

Assign out_and to A and B, out_or to A or B, out_xor to A xor B, out_not to not A, out_nand to not (A and B), and out_nor to not (A or B).

VHDL

signal A : std_logic := '1';
signal B : std_logic := '0';
signal out_and : std_logic;
signal out_or : std_logic;
signal out_xor : std_logic;
signal out_not : std_logic;
signal out_nand : std_logic;
signal out_nor : std_logic;
-- Assign output signals using logical operators
-- Your code here

Need a hint?

Use signal assignment with the <= operator and the exact logical expressions.

4

OUTPUT: Display the results using a process

Create a process that reports the values of out_and, out_or, out_xor, out_not, out_nand, and out_nor using report statements.

VHDL

signal A : std_logic := '1';
signal B : std_logic := '0';
signal out_and : std_logic;
signal out_or : std_logic;
signal out_xor : std_logic;
signal out_not : std_logic;
signal out_nand : std_logic;
signal out_nor : std_logic;

begin
    out_and <= A and B;
    out_or <= A or B;
    out_xor <= A xor B;
    out_not <= not A;
    out_nand <= not (A and B);
    out_nor <= not (A or B);

-- Create a process to report output values
-- Your code here

Need a hint?

Use a process with report statements and std_logic'image to convert signals to strings.