8051 microcontrollers

ASSIGNMENTS Check the appropriate answer in 1-10. 1. The process of accessing information on a floppy disk is a. random. b. serial. c. semirandom. 2. The operating system of a computer is defined as hardware that operates the floppy disk. a program that manages files on the disk. a group of programs that manages and directs hardware and software in the system. 3. The Editor is an assembly language program that reads and writes information on the disk. a high-level language program that allows the user to edit programs. a program that allows the user to write, modify, and store text in the computer system. 4. The Assembler is a compiler that translates statements from high-level language into assembly language. a program that translates mnemonics into binary code. an operating system that manages all the programs in the system. 5. A ...

SUMMARY A software development system and an assembler are essential tools for writing, assembling, testing, and debugging large assembly language programs. A disk-based microcomputer, its operating system, and assembler pro­grams can serve as a development system. All the operations of the computer are managed and directed by the operating system of the computer. The Assem­bler and other utility programs assist the user in developing software. The Edi­tor allows the user to enter text, and the Assembler translates mnemonics into machine code and provides error messages. The Debugger assists in debugging the program. The cross-assembler is an assembler program that operates under one type of MPU and can translate mnemonics of another MPU. The program thus assembled is in many ways similar to that of the hand assembly program except that the program written for the assembler includes assembler directives, which are instructions concerning how to assemble the program. The assembler...

7.4 WRITING PROGRAMS USING A CROSS-ASSEMBLER This section describes a commercially available Z80 cross-assembler and the pro­cess of assembling a program. The description in the following sections is equally applicable to both assemblers and cross-assemblers; therefore, the term assem­bler should be interpreted as the representation of both. The assembly process is illustrated with a simple example from the last chapter. 7.4.1 Z80Cross-Assembler The Z80 cross-assembler from 2500AD Software, Inc. * is one among several of such commercially available products. It includes two programs: X80 and LINK. In this assembler, translating mnemonics into binary code is a two-step process. The X80 translates the source file into modules of the Z80 code and generates two files: one is called the list (LST) file, and the other is called the object (OBJ) file. (This assembly process and the file names may vary slightly from assembler to assembler.) In addition to translating mnemonics, the assem...

7.3 ASSEMBLERS The assembler (or the cross-assembler), as defined before, is a program that trans­lates assembly language mnemonics or source code into binary executable code. Here, we are using the term assembler to include all the utility programs (such as Assembler and Linker) necessary for the assembly process. This translation pro­cess requires that the source program be written strictly according to the specified syntax of the assembler. The assembly language source program includes three types of statements: 1. The program statements in Z80 mnemonics, which are to be translated into binary code. 2. Comments, which are reproduced as a part of the program documentation. 3. Directives to the assembler that specify such items as starting memory loca­tions, label definitions, and required memory spaces for data. The first two types of statements have been used in the program of adding two Hex numbers in the last chapter. The format of these statements as they appear in an a...

7.2 OPERATING SYSTEMS The operating system of a computer is a group of programs that manages or over­sees all the operations of the computer. The computer transfers information con­stantly among peripherals such as a floppy disk, printer, keyboard, and video monitor. It also stores user programs under file names on a disk. (A file is defined as related records stored as a single entity.) The operating system is responsible primarily for managing the files on the disk and the communication between the computer and its peripherals. The functional relationship between the operating system and the computer's various subsystems is shown in Figure 7.3. Each computer has its own operating system. Nowadays, the most widely used operating system for IBM PC-compatible microcomputers is MS-DOS. In the 1970s and early 1980s when most microcomputers were designed to use 8-bit microprocessors, the CP/M (Control Program/Monitor) operating system was commonly used. The MS-DOS and CP/M...

7.1 MICROPROCESSOR-BASED SOFTWARE DEVELOPMENT SYSTEMS A software development system is simply a computer that enables the user to write, modify, debug, and test programs. In a microprocessor-based development system, a microcomputer is used to develop software for a particular micropro­cessor. Generally, the microcomputer has a large R/W memory (640K bytes or higher), disk storage, and a video terminal with a typewriter-like keyboard. The keyboard enables the user to write programs in- alphanumeric (alphabet and num­ber) characters, which are translated into American Standard Code for Informa­tion Interchange (ASCII) binary code; the keyboard (or the terminal) is known as ASCII keyboard (or terminal). The system includes programs that enable the user to develop software in either assembly language or high-level languages. This text will focus on developing programs in the Z80 assembly language. Conceptually, this type of microcomputer is similar to a single-board micro­computer ex...

Software Development Systems and Assemblers A software development system is a computer that enables the user to develop programs (soft­ware) with the assistance of other programs. The development process includes writing, modifying, testing, and debugging of the user programs. In the previous chapter, we dis­cussed how to write a simple assembly lan­guage program and translate its mnemonics into Hex code manually. In this chapter, we will de­velop assembly language programs with the help of four other programs: Editor, Assembler, Linker, and. Debugger. These programs enable the user to write programs in mnemonics, trans­late mnemonics into Hex and binary code, and debug the code. All the activities of the com­puter-hardware and software-are directed by another program, called the operating system . . This chapter describes an IBM PC (Per­sonal Computer)-based software development system, its hardware, and related programs. It also describes its operating systems MS-DOS (Microsoft...