VHDL - VHSIC Hardware Description Language
VHDL stands for Very high Speed Integrated Circuit Hardware Description Language. Some of the main points to ponder about it are as following below:
• VHDL is a non-proprietary language (IEEE-1076 1987/1993).
• VHDL is a widely supported type of Hardware Description Language
(HDL).
• VHDL is a kind of programming language.
• VHDL is similar to Ada - typing definitions, type checking, and
overloading.
• VHDL is also a simulation language.
• VHDL is even a kind of documentation language.
• VHDL is usable for register-transfer level and logic synthesis.
• VHDL has algorithmic level which are supported in parts.
Some properties of VHDL are as following:
• One of the main feature of it is it's Openness and
availability.
• Support of different design methodologies and
technologies.
• Independence from technologies and production
processes.
• Large variety of description possibilities.
• Worldwide design process, and project interchangeability
and reuse.
Object and Classes:
• VHDL mainly categorizes objects into four classes which are as following:
• Constant - an object whose value may not be changed.
• Signal - an object with a past history.
• Variable - an object with a single current value.
• File - an object used to represent file in the host environment.
• The type of an object represents its structure, composition, and
storage requirements.
• A class is relevant to the nature of the object and represents HOW the object is used in the model.
Types & packages
• Types and subtypes present the set of values and a set of operations,
structure, composition, and storage requirement that an object, such
as a variable or a constant or a signal, can hold.
• There exists a set of predefined types in package Standard.
• A package is a design unit which allows the specification of groups
of logically related declarations.
Basic Language Elements of VHDL are:
• Lexical elements, Identifiers
• Syntax
• Delimiters, Literals, Operators and Precedence
• Types and Subtypes
• Scalar type - integer, enumerate (IEEE Std. 1164), physical, real
• Composite type - arrays, records
• Access type
• File
• Attributes
• Aliases
• VHDL is a non-proprietary language (IEEE-1076 1987/1993).
• VHDL is a widely supported type of Hardware Description Language
(HDL).
• VHDL is a kind of programming language.
• VHDL is similar to Ada - typing definitions, type checking, and
overloading.
• VHDL is also a simulation language.
• VHDL is even a kind of documentation language.
• VHDL is usable for register-transfer level and logic synthesis.
• VHDL has algorithmic level which are supported in parts.
Some properties of VHDL are as following:
• One of the main feature of it is it's Openness and
availability.
• Support of different design methodologies and
technologies.
• Independence from technologies and production
processes.
• Large variety of description possibilities.
• Worldwide design process, and project interchangeability
and reuse.
Object and Classes:
• VHDL mainly categorizes objects into four classes which are as following:
• Constant - an object whose value may not be changed.
• Signal - an object with a past history.
• Variable - an object with a single current value.
• File - an object used to represent file in the host environment.
• The type of an object represents its structure, composition, and
storage requirements.
• A class is relevant to the nature of the object and represents HOW the object is used in the model.
Types & packages
• Types and subtypes present the set of values and a set of operations,
structure, composition, and storage requirement that an object, such
as a variable or a constant or a signal, can hold.
• There exists a set of predefined types in package Standard.
• A package is a design unit which allows the specification of groups
of logically related declarations.
Basic Language Elements of VHDL are:
• Lexical elements, Identifiers
• Syntax
• Delimiters, Literals, Operators and Precedence
• Types and Subtypes
• Scalar type - integer, enumerate (IEEE Std. 1164), physical, real
• Composite type - arrays, records
• Access type
• File
• Attributes
• Aliases
After reading this i hope you have understood all about VHDL.
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