CENG335_Lecture1_Introduction_to_CAD_and_VHDL

What are the earliest components used in digital circuits before integrated circuits?

Vacuum tubes and transistors.

What does CAD stand for in the context of digital logic design?

Computer Aided Design.

What is the purpose of CAD tools in digital circuit design?

To automate complex design processes that cannot be handled manually.

What are the two design entry methods mentioned for logic circuit design?

Schematic capture and writing source code in a hardware description language (HDL).

What is the function of the synthesis process in CAD tools?

Generating a logic circuit from an initial specification.

What does a functional simulator do in the context of circuit design?

Simulates logic expressions to verify that they will function as expected.

What step in the circuit design process comes after synthesis?

Functional simulation.

What is the purpose of timing simulation in circuit design?

To evaluate the expected delays of a designed logic circuit.

What is VHDL?

Very High Speed Integrated Hardware Descriptive Language, used for describing digital circuits.

What is the key difference between programming in traditional languages and using VHDL?

In VHDL, you are designing hardware, not programming.

What two main components make up VHDL code?

Entity and Architecture.

What was the original standard for VHDL adopted in 1987?

IEEE 1076.

What is meant by the term ‘entity’ in VHDL?

It lists the various inputs and outputs of the underlying circuitry.

How are logic functions expressed in VHDL?

By assigning values to variables that represent signals in the circuit.

What constructs must an architecture in VHDL include?

BEGIN and END.

Which operators does VHDL have built-in support for?

AND, OR, NOT, NAND, NOR, XOR, XNOR.

What must a signal name in VHDL start with?

A character.

What must the architecture have in relation to its associated entity?

A relation using 'OF'.

What does the assignment operator '<=' signify in VHDL?

It is used for assigning values within the architecture.

When was the revised version of the VHDL standard adopted?

In 1993, known as IEEE 1164.

Describe the propagation delay in logic circuits.

The time it takes for an output signal to occur after an input change.

What does the physical design tool do in CAD tools?

Maps a circuit specified in logic expressions into a comprehensive realization on a chip.

What is the ultimate goal of the synthesis process?

To create an optimal set of logic expressions for circuit realization.

What are ports in the entity declaration of a VHDL code?

The input and output signals for the entity.