VHDL

2

Introduction to VHDL

CHAPTER OBJECTIVES

• Evolution of HDL
• Comparison between two popular HDLs—Verilog and VHDL
• Features of VHDL
• Introduction to the three styles of VHDL modelling
• Delay models

2.1 HISTORY OF VHDL

VHDL is an acronym for very high speed integrated circuit language (VHSIC) hardware description language (HDL). VHDL is used to describe the logical structure and functions of digital systems that are varying from simple gates to complex PLDs (FPGAs, ASICs). It facilitates design specification and simulation of digital systems. Even though initially it was not meant for synthesis, it can be used for synthesis within a limited domain. It was initiated by the US Department of Defense in the 1980s as a need for a standard HDL for ...