# Contents

* 1 Introduction
o 1.1 Motivation: IC Design Methodologies
o 1.2 Contents and Structure of this Manual
* 2 Basic VHDL Concepts
o 2.1 Components of a VHDL Model
o 2.2 Entity Declaration
o 2.3 Architecture
o 2.4 Configuration Declaration
o 2.5 Packages
o 2.6 Additional Signal Characteristics
o 2.7 Analysis of VHDL Models
o 2.8 Simulation
* 3 Data Types
o 3.1 Scalar Types
o 3.2 Composite Types
o 3.3 Access Types
o 3.4 File Types
o 3.5 Type and Field Attributes

VHDL is an acronym which stands for VHSIC Hardware Description Language. VHSIC is yet another achronym which stands for Very High Speed Integrated Circuits. If you can remember that, then you're off to a good start. The language has been known to be somewhat complicated, as its title (as titles go). The acronym does have a purpose, though; it is supposed to capture the entire theme of the language, that is to describe hardware much the same way we use schematics.

• Quick introduction to VHDL
– basic language concepts
– basic design methodology
• Use The Student’s Guide to VHDL
or The Designer’s Guide to VHDL
– self-learning for more depth

• Architecture body
– describes an implementation of an entity
– may be several per entity
• Behavioral architecture
– describes the algorithm performed by the module
– contains
• process statements, each containing
• sequential statements, including
• signal assignment statements and

Contents
1 Introduction
11 Describing Structure 
12 Describing Behaviour 
13 Discrete Event Time Model
14 A Quick Example
2 VHDL is Like a Programming Language 
21 Lexical Elements 
211 Comments 
212 Identifiers
213 Numbers 
214 Characters
215 Strings 
216 Bit Strings
22 Data Types and Objects 
221 Integer Types 
222 Physical Types
223 Floating Point Types
224 Enumeration Types
225 Arrays
226 Records 
227 Subtypes 
228 Object Declarations 

This text focuses on presenting the basic features of the VHDL language in the context of its use for simulation. The text is targeted for use in sophomore and junior level courses in digital logic and computer architecture. The style of this text is intended to permit integration of the basic concepts underlying VHDL into existing courses without necessitating additional credit hours or courses for instruction.