Hardware Description Language (HDL) is a computer language used to describe electronic circuit structures. It is similar to conventional programming languages like C. There are many HDL used these days and every language has its own set of rules and advantages. Verilog and VHDL are two different hardware description languages that are most commonly used these days.
It is a weakly typed language. It is a case-sensitive language which means it will treat “bat” and “BAT” as two different words. All the codes in this language start with the word “module” and stop with the word “endmodule” and similar to the C language, the line ends with a semicolon.
It developed with time since 1995, now it is merged with the system Verilog. With constant up-gradation, it gets many features but still, it lacks library management. Overall it is convenient for a new generation to use for hardware modeling.
What is VHDL?
VHDL is also a hardware description language which is also known as Very High-Speed Integrated Circuit Hardware Description Language. It is used to model the working of digital systems. It was introduced in the 1980s and was developed by the U.S Department of Defence. Then after 1987, it is standardized by the Institute of Electrical and Electronics Engineers also known as IEEE.
It is based on Ada and Pascal languages and it also has some extra features that these languages lack. It functions in two modes, the first one is Statement execution in which it evaluates the triggered statements. And the latter one is, Event processing in which it processes the events in the queue.
It also has Boolean operators like nor and nand, which helps VHDL to represent operations precisely. It is a case insensitive language that means it treat upper case alphabets and lower case alphabets as the same data and Its projects are portable and multipurpose in many ways.
As it is based on Ada and Pascal languages it is more difficult to learn because these languages are not that much popular among programmers. It is a strongly typed language that allows users to create some extra and complex data types.
Main Differences Between Verilog and VHDL
- The main difference between Verilog and VHDL is that Verilog is an HDL based on C language, on the other hand, VHDL is also an HDL but it is based on Ada and Pascal languages.
- Verilog was introduced in 1984 whereas VHDL was introduced in 1980 by the US Department of Defence.
- Verilog is a newer and case-sensitive language, on the other hand, VHDL is older and case insensitive language.
- As Verilog is based on a popular C language hence it is easier to learn but VHDL is difficult to learn as it is based on non-conventional languages.
- Verilog is used to model electronic systems and circuits like microprocessors and flip-flops whereas VHDL is used to describe digital and mixed signals like integrated circuits.
Conclusion
Hardware description languages are needed for this generation as most of the things around us are dependent on electronic systems and circuits. These languages made tasks easier and effective. Many languages can be used for this task, Verilog and VHDL are the two most popular languages among programmers.
Many same tasks can be performed using both languages but Verilog is a compact language hence needed fewer lines of code for completion of tasks whereas VHDL will require more long codes. Verilog is an easier language as it is based on C language on the other hand VHDL is difficult to learn as it is based on Ada and Pascal languages.
References
- https://ieeexplore.ieee.org/abstract/document/545676/
- https://trilobyte.com/pdf/golson_clark_snug16.pdf