Microprocessor System

A functioning microprocessor is not simply a tiny piece of silicon which can replace a room full of data processing equipment. It requires many other components to make it work. The term "microcomputer" refers to the assembly of parts which make the microprocessor a useful working tool.

The microprocessor unit (MPU) is the “brain” of the system and directs all of the other parts to perform their function at the proper time.

An MPU is a complex integrated circuit. It is a highly miniaturized version of the minicomputers. A typical MPU will have the equivalent of about 7,000 transistors, diodes, resistors, etc., on a single piece of silicon less than 1/16 in. square.

The job of the microprocessor is to move or alter chunks of information in an orderly fashion. The chunks of information are reduced to coded form represented as binary numbers which the microprocessor can manipulate. The MPU can only do extremely elementary actions, such as move a piece of data, add two numbers, increment a counter, etc.

Each one of the elementary operations of an MPU has its own binary code. The sequence of codes which makes the processor do its intended function is called a program or software. The inherent flexibility of an MPU comes from the fact¹ that instructions can be combined in limitless variations.

The MPU can perform only one operation at a time. A clock, which is simply a stream of regular pulses, is required to control the proper sequencing. During operation the microprocessor fetches an instruction from memory, decodes the function, performs the proper activity and fetches the next instruction. It repeats this sequence as long as power is on and the clock is running².

MPUs are measured by the size of the piece of data which can be transferred to and from memory. Most MPUs are 4-bit, 8-bit or 16-bit in size.

An MPU system also needs a way to get information to the outside world and to bring in outside information that has been properly coded. Input/output devices exist which perform this function. Generally, they come in two types, parallel and serial. Parallel devices can send and receive coded data in one chunk. Serial devices transform the coded data into a single stream which must be reconstructed at the receiving end.

The minimum MPU system will be composed of the following: an MPU, memory, some form of input/output, a clock and some source of power.

Notes

1 the inherent flexibility of an MPU comes from the fact — свойственная микропроцессорному блоку гибкость исходит из того

2 it repeats this sequence as long as power is on and the clock is running — он повторяет эту последовательность до тех пор, пока включена энергия и работает синхронизатор

III.Answer the following questions on the contents of the text:

1. What is a microprocessor unit? 2. What are the chunks of information reduced to? 3. The MPU can perform only one operation at a time, can't it? 4. How are MPUs measured? 5. What can parallel and serial devices do?

IV.Give the main points of the text.

V. Speak about the job of the microprocessor.

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