VHDL (programmging language)
VHDL, short for VHSIC Hardware Description Language, is a hardware description language that plays a crucial role in the fields of computer programming and engineering. Developed in the 1980s with support from the US Department of Defense, VHDL was designed to create a standardized means of describing complex computer components and circuits, and it became publicly available in 1985, with further standardization occurring in 1987. This language allows engineers to describe hardware at various levels of abstraction, ranging from individual logic gates to intricate circuit designs, enabling detailed modeling and simulation.
One of VHDL's primary advantages is its compatibility with numerous design and simulation tools, making it possible for engineers to test and validate component performance before physical construction. Despite its widespread use and industry standard status, VHDL is often regarded as complex and challenging for newcomers, which can be a barrier for individual developers or smaller firms due to the costs associated with specialized software tools. Nonetheless, mastering VHDL can facilitate collaboration among team members across various projects, enhancing design efficiency.
Over the years, VHDL has undergone multiple revisions, with significant updates in 1994, 2000, 2002, 2007, 2008, and most recently in 2019, reflecting its ongoing evolution to meet the demands of the engineering community.
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VHDL (programmging language)
VHDL is a hardware description language commonly used by computer programmers and computer engineers. It was first developed in the 1980s, when the US Department of Defense wanted a more standardized language for developing computer components. It premiered to the public in 1985 and was standardized in 1987. It has gone through numerous revisions since.
It is used to describe the structure and workings of a computer part, from simple logic gates to larger circuits, in extreme detail. Because the language is extremely commonplace, it is compatible with many forms of imaging and simulation software. This allows computer engineers to test the theoretical performance of individual components and entire parts before the computer system is constructed.
Learning VHDL allows an engineer or programmer to work on a wide variety of projects. Additionally, because the language is commonly used across projects, it allows engineers within the same firm to collaborate and help one another. However, VHDL is commonly considered a complex, difficult language to learn. Many of the tools it works with are also specialized or expensive. For this reason, it may be impractical for some individual developers or smaller firms to learn VHDL.
Background
The VHSIC Hardware Description Language, commonly called VHDL, was first developed in the early 1980s. At the time, the US Department of Defense had taken an interest in developing and researching high-speed circuits. Although the department was willing to fund the research of computer and electronic engineers, these specialists soon realized that they did not have the tools necessary to develop large, complex circuits. They had programming languages that allowed them to modify individual logic gates, but little else.
The Department of Defense decided to fund the creation of a new type of computer language. It gathered a team of programmers and engineers from several major technology companies, and then funded the creation of a hardware description language. This eventually became VHDL. The language was released to the public in 1985, and then standardized in 1987 through the Institute of Electrical and Electronics Engineers (IEEE).
Overview
Hardware description languages, including VHDL, are made up of textual descriptions of hardware. They can describe signals, components, inputs, outputs, and multiple architectures at once. This allows computer engineers to build more complex circuits, leading to more powerful computers.
VHDL combines the features of numerous other types of programing languages. In some ways, it functions as a simulation modeling language. This means that it can be utilized to describe the behavior of carefully modeled computer chips. These bits of code can then be saved, modified, or combined to describe larger pieces of hardware. It also functions as a design entry language, meaning that it allows computer engineers to express their ideas about physical objects as a computer program. The language is a means of expressing the movements and characteristics of parts with precise written communication.
Because of how precise engineers can be when describing theoretical parts using VHDL, the language can often function as a test language. Engineers can use the computer code written in VHDL to precisely check how a piece of hardware, such as a computer chip or circuit, will function once built.
One of the most common reasons computer engineers code in VHDL is that the language has become an industry standard. The language is supported by the vast majority of other design tools, meaning that engineers will rarely have to change their code to work with obscure programs. Additionally, it means that previously written pieces of code are likely to be compatible with newer, more powerful generations of software.
VHDL is used for numerous purposes within the computer engineering community. It can be used to simulate the entirety of a physical part, allowing engineers to test both the part as a whole and as an individual component in the same simulator. This allows engineers to discover problems, and then quickly and precisely isolate the source of that problem.
Design firms experienced in VHDL often find that the coding language allows them to design hardware faster than many other proprietary languages. Additionally, because VHDL can be used for such a wide variety of purposes, team members working on different projects can be trained in the same programming language. This allows them to collaborate more easily, improving the overall efficiency of the design firm.
Despite these advantages, utilizing VHDL as a firm has some drawbacks. VHDL is a large, complex computer language. Many engineers and programmers find it more difficult to learn than many alternatives. However, because the language covers so many topics, many engineers will only need to learn the aspects relevant to their specific job.
Prices for software designed to interact with VHDL, such as simulation and synthesis tools, have historically been higher than other similar languages. Although prices have fallen over time, many types of software designed to work with VHDL are still parts of large, expensive software bundles. For this reason, more price-efficient languages may be appealing to engineers and developers on a budget.
VHDL is an extremely broad language designed to complete many tasks. For this reason, some other languages may be more useful in specific circumstances. Understanding when VHDL will work best, and when a more obscure language will create a better product, relies on the experience of the engineers and developers.
VHDL has gone through numerous forms and versions since its release. In 1994, the standard language was revised with minimal changes. It was revised again in 2000 and 2002. In 2007, the VHDL Procedural Language Application Interface standard, also called VHDL 1076c-2007, was released. Another version of VHDK was released in 2008. A new VHDL standard was approved in 2019.
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