implementation of electronic nose using vhdl code on fpga

Electronic Design Automation (EDA), also known as computer-aided electronic design (ECAD) , is a category of software tools for the design of electronic systems such as integrated circuits and printed circuit boards. The tools work together in a design flow that chip designers use to design and analyse entire semiconductor chips. Since a modern semiconductor chip can have billions of components, EDA tools are essential for its design. This article specifically describes EDA with regard to integrated circuits.
Before EDA, the integrated circuits were designed by hand and were designed manually. Some advanced stores used geometric software to generate tapes for the Gerber photo plotter, but even those digital recordings copied from mechanically extracted components. The process was fundamentally graphic, with the translation of electronics to the graphics made manually. The best known company of this era was Calma, whose GDSII format survives.

In the mid-1970s, developers began to automate design along with writing. Placement and routing tools (place and route) were developed. The Design Automation Conference procedures cover much of this era.The next era began around the time of the publication of the "Introduction to VLSI Systems" by Carver Mead and Lynn Conway in 1980. This ground-breaking text advocated chip design with programming languages that compiled silicon . The immediate result was a considerable increase in the complexity of the chips that could be designed, with better access to the design verification tools that used the logical simulation. Often the chips were easier to design and more likely to work properly, since their designs could be simulated more thoroughly prior to construction. Although languages and tools have evolved, this general approach of specifying desired behaviour in a textual programming language and letting tools derive detailed physical design remains the basis of IC digital design today.

The first EDA tools were produced academically. One of the most famous was the "Berkeley VLSI Tools Tarball", a set of UNIX utilities used to design the first VLSI systems. Still widely used are the heuristic logic minimiser Espresso and Magic.
Another crucial development was the formation of MOSIS, a consortium of universities and manufacturers that developed an economical way to train student chip designers by producing real integrated circuits. The basic concept was to use reliable, low-cost and relatively low-technology IC processes and pack a large number of projects per wafer, with only a few copies of each project's chips. The cooperating manufacturers donated processed wafers, or sold them at cost, seeing the program as useful for their own long-term growth.