NOTES SUBJECT: Microprocessors and Interfacing Devices
INDEX CHAPTER 1 1.1 Introduction to Microprocessor 1.2 Microprocessor architecture and its operations 1.3 Memory, Input & output devices 1.4 Logic devices for interfacing 1.5 The 8085 MPU, Example of an 8085 based computer 1.6 Memory interfacing CHAPTER 2 2.1 Basic interfacing concepts 2.2 Interfacing output displays 2.3 Interfacing input devices 2.4 Memory mapped I/O 2.5 Flow chart symbols 2.6 Data Transfer operations 2.7 Arithmetic operations 2.8 Logic Operations 2.9 Branch operation 2.10 Writing assembly language programs 2.11 Programming techniques: looping, counting and indexing CHAPTER 3 3.1 Additional data transfer and 16 bit arithmetic instruction 3.2 Arithmetic operations related to memory 3.3 Logic operation: rotate, compare 3.4 Counter and time delays 3.5 Illustrative program 3.5.1 Hexadecimal counter 3.5.2 zero-to-nine, (module ten) counter 3.5.3 Generating pulse waveforms 3.5.4 Debugging counter and time delay 3.6 Stack, Subroutine 3.7 Restart, Conditional call and return instructions 3.8 Advance subroutine concepts 3.9 The 8085 Interrupts 3.9.1 8085 vector interrupts. CHAPTER 4 4.1 BCD-to-Binary conversion 4.2 Binary-to-BCD conversion 4.3 BCD-to-Seven segment code converter 4.4 Binary-to-ASCII 4.5 ASCII-to-Binary code conversion 4.6 BCD Addition 4.7 BCD Subtraction
4.8 4.9 Introduction to Advance instructions and Application Multiplication, Subtraction with carry CHAPTER 5 5.1 8255 Programmable peripheral interface 5.2 interfacing keyboard and seven segment display, 5.3 8254 (8253) programmable interval timer, 5.4 8259A programmable interrupt controller, 5.5 Direct Memory Access and 8237 DMA controller. 5.6 Introduction to 8086 microprocessor: Architecture of 8086, Pin diagram 5.7 Functional block diagram, Register organization.
UNIT 1 1.1 INTRODUCTION TO MICROPROCESSOR: Microprocessors are regarded as one of the most important devices in our everyday machines called computers. Before we start, we need to understand what exactly microprocessors are and their appropriate implementations. Microprocessor is an electronic circuit that functions as the central processing unit (CPU) of a computer, providing computational control. Microprocessors are also used in other advanced electronic systems, such as computer printers, automobiles, and jet airliners Typical microprocessors incorporate arithmetic and logic functional units as well as the associated control logic, instruction processing circuitry, and a portion of the memory hierarchy. Portions of the interface logic for the input/output (I/O) and memory subsystems may also be infused, allowing cheaper overall systems. While many microprocessors and single-chip designs, some highperformance designs rely on a few chips to provide multiple functional units and relatively large caches. When combined with other integrated circuits that provide storage for data and programs, often on a single semiconductor base to form a chip, the microprocessor becomes the heart of a small computer, or microcomputer. Microprocessors are classified by the semiconductor technology of their design (TTL, transistor-transistor logic; CMOS, complementary-metal-oxide semiconductor; or ECL, emitter-coupled logic), by the width of the data format (4-bit, 8-bit, 16-bit, 32-bit, or 64-bit) they process; and by their instruction set (CISC, complex-instruction-set computer, or RISC, reduced-instruction-set computer; see RISC processor). TTL technology is most commonly used, while CMOS is preferred for portable computers and other battery-powered devices because of its low power consumption. ECL is used where the need for its greater speed offsets the fact that it consumes the most power. Four-bit devices, while inexpensive, are good only for simple control applications; in general, the wider the data format, the faster and more expensive the device. CISC processors, which have 70 to several hundred instructions, are easier to program than RISC processors, but are slower and more expensive. Microprocessors have been described in many different ways. They have been compared with the brain and the heart of humans. Their operation has been likened to a switched board, and to the nervous system in an animal. They have often been called microcomputers. The original purpose of the microprocessor was to control memory. That is what they were originally designed to do, and that is what they do today. Specifically, a microprocessor is “a component that implements memory. A microprocessor can do any information-processing task that can be expressed, precisely, as a plan. It is totally uncommitted as to what its plan will be. It is a truly general-purpose informationprocessing device. The plan, which it is to execute—which will, in other words, control its operation—is stored electronically. This is the principle of “stored program control”. Without a program the microprocessor can do nothing. With one, it can do anything. Furthermore, microprocessors can only perform information-processing tasks. To take action on the outside world, or to receive signals from it, a connection must be provided between the microprocessor’s representation of information (as digital electronic signals) and the real world representation. 4-BIT MICROPROCESSORS: Historically, the 4-bit microprocessor was the first general-purpose microprocessor introduced on the market. The basic design of the early microprocessors was derived from that of the desk calculator. The Intel 4004, a 4-bit design, was the grandfather of microprocessors. Introduced in