Abstract :
Since the first microprocessor, built in 1971, micro-processors have evolved at a dramatic pace in terms of technology, processing power, dissipation, and functionality. This paper makes a brief overview of the history, presents major areas of importance in design and summarisizes some approaches that are currently being considered for the future. The 4 bit 4004 from INTEL CORP. was the first micro-programmable computer on a chip. It consisted of a 4 bit parallel adder, 16 bit registers, an accumulator and a stack on a single chip. Being able to execute 45 instructions, the chip contained 2300 transistors. In the early days microprocessors were programmed in machine language; however, the quick evolution of superior system architectures and superior high level language availability caused an explosion in the domain of microprocessor usage. MOORE´s law which states that the number of transistors integrated on a piece of silicon generally doubles every two years has been maintained practically for the microprocessor. In the initial times, Memory, Input/Output, Timer, and other special functions were found on separate chips. As the Technology of processing improved it became possible to pattern much finer geometries on silicon, therefore, either more powerful computers with sophisticated functions could be built economically or the existing Microprocessor became affordable for a vast spectrum of applications such as in toys, TV, automotive, instrumentation, CAD/CAM tools, telecommunication, smart cards, personal computers etc.. A microprocessor is a central arithmetic and logic unit of a computer.