samir's book

ch1 Overview of Digital Design with Verilog" HDL
1.1 Evolution of Computer Aided Digital Design
Digital circuit design has evolved rapidly over the last 25 years.

With the advent of VLSI (Very Large Scale Integration) technology, designers could
design single chips with more than 100,000 transistors.

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1.2 Emergence of HDLs
For a long time, programming languages such as FORTRAN, Pascal, and C were being used to describe computer programs that were sequential in nature.

Even though HDLs were popular for logic verification, designers had to manually translate the HDL-based design into a schematic circuit with interconnections between gates.

Thus, logic synthesis pushed the HDLs into the forefront of digital design.

HDLs also began to be used for system-level design.

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1.3 Typical Design Flow
A typical design flow for designing VLSI IC circuits is shown in Figure 1-

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The behavioral description is manually converted to an RTL description in an
HDL.