Microprocessors, Microcomputers, and Assembly Language
this topic is concerned primarily with microprocessor architecture in the context of microprocessor-based products. The microprocessor-based systems are discussed in terms of three components the microprocessor, memory, and input and output and their communication process. The role of the programming languages, from the machine language to high-level languages, is presented in the context of the system.
The material is presented in a format similar to the view from an airplane preparing lo land. As the plane circles, one observes a view without any details. As the plane descends, one begins to see the same view but with more details. Chapter I presents the microprocessor from two points of view: the microprocessor as a programmable embedded device in a product and as an element of a computer system, and how it communicates with memory and I/O. The chapter also discusses the role of assembly language in microprocessor-based products and presents an overview of various types of computers from large computers to microcomputers and their applications. we will describes a generalized model of a microprocessor-based system and its three components: the microprocessor, memory, and input and output (I/O). we will examine these components in detail and discuss how memory and I/O devices interface with the Z80 microprocessor.
PREREQUISITES
The reader is expected to know the following
concepts:
· Number systems (binary, octal, and hexadecimal) and their conversions.
· Boolean algebra, logic gates, flip-flops, and registers.
· Concepts in combinational and sequential logic.
Microprocessors, Microcomputers, and Assembly Language
The microprocessor plays a significant role in the everyday functioning of industrialized societies. The microprocessor can be viewed as a programmable logic device that can be used to control processes or to turn on/off devices. On the other hand, the microprocessor can be viewed as a data processing unit or a computing unit of a computer. The, microprocessor is a programmable integrated device that has computing and decision making capability, similar to that of the central processing unit (CPU) of a computer. Nowadays, the microprocessor is being used in a wide range of products called microprocessor-based products or systems. The microprocessor can be embedded in a larger system, can be a stand alone unit controlling processes, or it can function as the CPU of a computer called a microcomputer. This chapter introduces the basic structure of a microprocessor-based product and shows how the same structure is applicable to microcomputers and other large (mini- and mainframe) computers. Later in the chapter, microprocessor applications are presented in the context of the entire spectrum of various computer applications.
The microprocessor communicates and operates in the binary numbers 0 and I, called bits. Each microprocessor has a fixed set of instructions in the form of binary patterns called a machine language. However, it is difficult for humans to communicate in the language of Os and Is. Therefore, the binary instructions are given abbreviated names, called mnemonics, which form the assembly language for a given microprocessor. This chapter explains both the machine language and the assembly language of the microprocessor known as the Z80. The advantages of assembly language are compared with such English-like languages as Basic and FORTRAN.
OBJECTIVES
· Draw a block diagram of a microprocessor-based system and explain the functions of each component: microprocessor, memory, and I/O, and their lines of communication (the bus)
· Explain the terms SSI, MSI, and LSI.
· Define the terms bit, byte, word, instruction , software, and hardware
· Explain the difference between the machine language and the assembly language of a computer.
· Explain the terms low-level and high-level languages.
· Explain the advantages of an assembly language over high-level languages.