The main difference between Verilog and VHDL is that Verilog is based on C language while VHDL is based on Ada and Pascal languages.
Both Verilog and VHDL are Hardware Description Languages (HDL). These languages help to describe hardware of digital system such as microprocessors, and flip-flops. Therefore, these languages are different from regular programming languages. VHDL is an older language whereas Verilog is the latest language.
Key Areas Covered
1. What is Verilog
– Definition, Features
2. What is VHDL
– Definition, Features
3. What is the Difference Between Verilog and VHDL
– Comparison of Key Differences
Key Terms
C Language, Verilog, VHDL
What is Verilog
Verilog is an HDL (Hardware Description Language). The latest stable version of Verilog is IEEE 1364-2005. Verilog is a case sensitive language which only uses lowercase. It supports simulation. In other words, it is possible to create a model of a function and simulate it before building the real system. The base language of Verilog is C. Therefore, a programmer who is familiar with C can learn Verilog quickly.
Module is the basic building block in Verilog. It provides information about input and output ports and hides the internal implementation details. The syntax of module is as follows. Every Verilog program starts with the keyword “module” and ends with the keyword “endmodule”.
module <module_name> (input,output);
<program logic>
endmodule
What is VHDL
VHDL is an HDL that helps to describe circuits in digital systems. A hardware module in VHDL is called an entity. The syntax is as follows. The entity starts with “entity” and ends with “end” keyword.
entity <entity_name> is
port declaration;
end entity_name;
There are other keywords such as In, Out, Inout and Buffer. In represents the ports we can read. Out represents ports we can write. Inout represents ports we can read and write. Moreover, it is possible to read and write to a Buffer port, and it can only have one source.
There are main three types of modeling in VHDL. They are as follows.
Data flow modeling – Parallel signals represent the flow of data through an entity
Behavioral modeling – Represents the behavior of an entity as a set of statements to execute one after the other in a specified order
Structured modeling – Represents an entity as a set of interconnected components
Difference Between Verilog and VHDL
Definition
Verilog is an HDL used to model electronic systems while VHDL is an HDL used in electronic design automation to describe digital and mixed-signal systems such as field programmable gate arrays and integrated circuits.
Base Language
The main difference between Verilog and VHDL is that Verilog is based on C language while VHDL is based on Ada and Pascal languages.
Case Sensitive
Moreover, one other difference between Verilog and VHDL is that Verilog is case sensitive while VHDL is not case sensitive.
Introduced Time Period
Verilog is a newer language than VHDL as Verilog was introduced in 1984 while VHDL was introduced in 1980.
Complexity
Complexity is another difference between Verilog and VHDL. VHDL is complex than Verilog.
Conclusion
Verilog and VHDL are two Hardware Description Languages (HDL) that help to describe digital electronic systems. The main difference between Verilog and VHDL is that Verilog is based on C language while VHDL is based on Ada and Pascal languages.
Reference:
1. Tala, Deepak Kumar. Wire And Reg In Verilog, 1 Feb. 1970, Available here.
2. “Verilog.” Wikipedia, Wikimedia Foundation, 1 Dec. 2018, Available here.
3. “VHDL.” Wikipedia, Wikimedia Foundation, 6 Jan. 2019, Available here.
4. Verilog Tutorial: Introduction to Verilog, Beginners Point Shruti Jain, 13 Aug. 2017, Available here.
Image Courtesy:
1. “Verilog Bus” By Inductiveload – Own work (Public Domain) via Commons Wikimedia
2. “Vhdl signed adder source” By Vhdl_signed_adder.png: RevRagnarokderivative work: Bernard Ladenthin – Own work, This file was derived from: Vhdl signed adder.png (CC BY-SA 3.0) via Commons Wikimedia
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