Principles of Microcomputer - Introduction

Microcomputer principle

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Preface

This series of blog is mainly to watch the teacher Yu of Xi'an University of Electronic Science and technology 2009 Recorded in 《 Microcomputer principle video 》, Curriculum CPU With 8086CPU Take as an example to explain the course ！

The whole course revolves around the following control block diagram ,CPU How to receive external physical signals , And control the change of external environment according to the change of external physical signal .

External equipment and CPU Required when connected Design interface circuit , Connect the two through the interface circuit .

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One 、 Composition of microcomputer system

The composition system of microcomputer is divided into hardware subsystem and software subsystem ;

1. Early computer hardware systems

The composition of the early computer hardware system is as follows ：

CPU By the control unit and ALU form , There are three kinds of information in the whole hardware system , Control information （ Blue ）, Data and information （ green ） And address information （ There are multiple storage units in the memory , The location of these storage units is the address information ）.
Bus ： A path used to transmit information . According to the information, it can be divided into data bus （DB)、 Address bus （AB) And control bus （CB)

2. Hardware composition of microcomputer system

To reduce CPU Volume , Semiconductor manufacturers quote multiplexed pins , Reduce CPU pin number .

System level bus does not Light solves the problem of pin multiplexing and separation, and also solves the problem of pin driving ability .
ROM Memory is called program memory ,RAM Memory is called data memory .
8086 There is no inside ROM and RAM, So you need a bus to mount .

Instructions — Is a kind of binary code , The process of converting a high-level language into a machine language is called compilation ;
whatever IO Equipment and CPU Communication must be set IO Interface circuit ！
Such as display and CPU The connection between them needs to be through the graphics card .
IO Address of the interface ：CPU To someone IO The operation of the equipment is actually to IO Interface address for operation .

8086 Yes 16 Root address line , and IO The interface circuit has only one interface , So you need to use IO Address decoding circuit . That is to use the decoding knowledge in digital electronics ！

Two 、 Memory

A word is divided into low byte and high byte , The high byte is placed at the high address , The low byte is placed at the low address

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