Introduction to Microprocessor Design
Introduction to microprocessor design
Processors are the brains of computers. Other components allow a computer to store or retrieve data and to input or output data, but the processor performs computations and does something useful with the data. It is the processor that determines what action will happen next within the computer and directs the overall operation. Processors in early computers were created out of many separate components, but as technology improved it became possible to integrate all of the components of a processor onto a single piece, or chip, of silicon. These integrated circuits are called microprocessors. Despite all the different functions a microprocessor performs, in the end it is only a collection of transistors and wires. The job of microprocessor design is ultimately deciding how to connect transistors to be able to quickly execute the commands that run programs. As the number of transistors on a processor has grown from thousands to millions that job has become steadily more complicated, but a microprocessor is still just a collection of transistors connected to operate as the brain of a computer. The story of the first microprocessor is therefore also the story of the invention of the transistor and the integrated circuit.
The transistor: Transistors were invented at Bell Laboratories in New Jersey in 1947 by John Bardeen (1908–1991), Walter Brattain (1902–1987), and William Shockley (1910–1989). A transistor is a miniature electronic component that can do two different jobs. It can work either as an amplifier or a switch. When it works as an amplifier, it takes in a tiny electric current at one end (an input current) and produces a much bigger electric current (an output current) at the other. Transistors can also work as switches. A tiny electric current flowing through one part of a transistor can make a much bigger current flow through another part of it. In other words, the small current switches on the larger one. Doping Silicon, have two different types of silicon. If we put them together in layers, making sandwiches of p-type and n-type material, we can make different kinds of electronic components that work in all kinds of ways. There are PNP and NPN transistors that have different applications.
The IC: Integrated Circuits are defined as the circuit that comprises elements that are inseparable and interconnected electrically in such a way that the IC cannot be separated for the reason of commerce and construction. Myriad technologies can be used to build such a circuit. Today what we call an IC, was originally known as a monolithic integrated circuit. It is believed that Kilby created the first working IC back in 1958 and he won the Nobel Prize in Physics in 2000 for his hard work. The first buyer for this invention was the US Air Force. The procedure of manufacturing of an integrated circuit starts with a big single crystal of silicon, shaped like a long solid pipe, which is “salami sliced” into thin discs (about the size of a compact disc) called wafers. The wafers are marked out in a lot of identical square or rectangular areas, each of which will build up a single silicon chip (sometimes called a microchip). Thousands, millions, or billions of apparatus are then produced on each chip by doping dissimilar areas of the surface to turn them into n-type or p-type silicon. There are different types of ICs such as digital ICs analog ICs and Mixed signal ICs.
