Книга: Introduction to Microprocessors and Microcontrollers

Terminology

Integrated circuits

An electronic circuit fabricated out of a solid block of semiconductor material. This design of circuit, often called a solid state circuit, allows for very complex circuits to be constructed in a small volume. An integrated circuit is also called a ‘chip’.

Microprocessor (?p)

This is the device that you buy: just an integrated circuit as in Figure 1.6. On its own, without a surrounding circuit and applied voltages it is quite useless. It will just lie on your workbench staring back at you.

Microprocessor-based system

This is any system that contains a microprocessor, and does not necessarily have anything to do with computing. In fact, despite all the hype, computers use only a small proportion of all the microprocessors manufactured. Our garage door opening system is a microprocessor-based system or is sometimes called a microprocessor-controlled system.

Microcomputer

The particular microprocessor-based systems that happen to be used as a computer are called microcomputers. The additional circuits required for a computer can be built into the same integrated circuit giving rise to a single chip microcomputer.

Microcontroller

This is a complete microprocessor-based control system built onto a single chip. It is small and convenient but doesn’t do anything that could not be done with a microprocessor and a few additional components. We’ll have a detailed look at these in a later chapter.

MPU and CPU

An MPU is a MicroProcessor Unit or microprocessor. A CPU is a Central Processing Unit. This is the central ‘brain’ of a computer and can be (usually is) made from one or more microprocessors. The IBM design for the ‘Blue Gene’ supercomputer includes a million processors!

Remember:

MPU is the thing

CPU is the job.

Micro

The word micro is used in electronics and in science generally, to mean ‘one-millionth’ or 1?10^–6. It has also entered general language to mean something very small like a very small processor or microprocessor. It has also become an abbreviation for microprocessor, microcomputer, microprocessor-based system or a micro controller – indeed almost anything that has ‘micro’ in its name. In the scientific sense, the word micro is represented by the Greek letter ? (mu). It was only a small step for microprocessor to become abbreviated to ?P.

Some confusion can arise unless we make sure that everyone concerned is referring to the same thing.

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