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Unformatted text preview: The Requirement The development of VHDL was initiated in 1981 by the United States Department of Defense to address the hardware life cycle crisis. The cost of reproducing electronic hardware as technologies became obsolete was reaching crisis point, because the function of the parts was not adequately documented, and the various components making up a system were individually verified using a wide range of different and incompatible simulation languages and tools. The requirement was for a language with a wide range of descriptive capability that would work the same on any simulator and was independent of technology or design methodology. Very important was the concept of concurrency to cope with the parallelism of digital hardware. Sequential statements to model very complex functions in a compact form were also allowed. Standardization ( VHDL87 ) In 1987, VHDL was standardized by the American Institute of Electrical and Electronics Engineers (IEEE) The standardization process for VHDL was unique in that the participation and feedback from industry was sought at an early stage. All rights to the language definition were given away by the DoD to the IEEE in order to encourage industry acceptance and investment. A Brief History of VHDL VHDL '93 As an IEEE standard, VHDL must undergo a review process every 5 years (or sooner) to ensure its ongoing relevance to the industry. The first such revision was completed in September 1993. Apart from the file handling procedures and some syntax these two versions of the standard are compatible. VHDL-AMS A new and difficult stage was entered with the effort to upgrade VHDL with analogue and mixed-signal language elements. The upgrade is called VHDL-AMS (analogue- mixed- signal) and it is a superset of VHDL. For the time being, only simulation is feasible for the analogue part because analogue synthesis is a very complex problem affected by many boundary conditions. VHDL 2002 The 2002 standard is essentially the same as the 1993 standard, but certain ambiguities have been removed. A Brief History of VHDL A Brief History of VHDL International Standards IEEE Std 1076-1987 IEEE Std 1076-1993 IEEE Std 1076-2002 Analogue- and mixed-signal extension: VHDL-AMS IEEE Std 1076.1-1999 International Standards IEEE Std 1076-1987 IEEE Std 1076-1993 IEEE Std 1076-2002 Analogue- and mixed-signal extension: VHDL-AMS IEEE Std 1076.1-1999 VHDL is the VHSIC Hardware Description Language. VHSIC stands for Very High Speed Integrated Circuits. VHDL is an international standard, regulated by the IEEE . The definition of the language is non-proprietary. Like any standard helps to reduce confusion and makes interfaces between tools and companies easier....
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This note was uploaded on 05/06/2010 for the course EECC 0306-351 taught by Professor Marcinlukowiak during the Winter '10 term at RIT.
- Winter '10