Microprocessor and its Applications

Transcription

1 NH 67, Karur Trichy Highways, Puliyur C.F, Karur District M.C.A. (MASTER OF COMPUTER APPLICATIONS) SEMESTER III MC MICROPROCESSORS AND ITS APPLICATIONS COURSE MATERIAL Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 1

2 ANNA UNIVERSITY CHENNAI SYALLABUS M.C.A - MASTER OF COMPURTER APPLICATIONS SEMESTER III MC9232 MICROPROCESSORS AND ITS APPLICATIONS L T P C UNIT I THE 8086 PROCESSOR - SOFTWARE ASPECTS 11 Evolution of Microprocessors architecture Addressing modes- Instruction set and assembler directives Assembly language programming Interrupts and interrupt service routines. UNIT II 8086 SYSTEM DESIGN signals description Basic configurations - System bus timing System design using 8086 Minimum mode /Maximum modes 8086 system and timings. UNIT III INTERFACING CONCEPTS 10 Memory Interfacing and I/O interfacing - Parallel communication interface Serial communication interface Timer Keyboard /display controller Interrupt controller DMA controller Programming and applications. UNIT IV ADVANCED PROCESSORS 7 Intel Internal Architectural Register Organization Internal Block Diagram Modes of operation Real Address Mode Protected Virtual Address mode Privilege Protection - Architectural features and Register Organization of i386, i486 and Pentium processors. UNIT V BUILDING SYSTEMS 7 Bus Concepts Bus Standards The Peripheral Component Interconnect (PCI) Bus Universal Serial Bus (USB) Platform Architectures. Total=45 Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 2

3 REFERENCES: 1. A. K. Ray & K. M. Bhurchandi, Advanced Microprocessors and peripherals- Architectures, Programming and Interfacing, TMH, 2002 reprint. 2. Barry B. Brey, The Intel Microprocessors, 8086/8088, 80186/80188, 80286, 80386, 80486, Pentium, PentiumPro Processor, PentiumII, PentiumIII, PentiumIV, Architecture, Programming & Interfacing, 6 th Edition, Pearson Education/PHI, Yu-cheng Liu, Glenn A. Gibson, Microcomputer systems: The 8086/8088 Family architecture, Programming and Design, PHI Peter Abel, IBM PC Assembly language and programming, Prentice Hall of India Pvt. Ltd. 5. Websites of latest processors. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 3

4 BASICS OF MICROPROCESSORS Microprocessor: The Central Processing Unit (CPU) of a microcomputer. CPU on a single chip. Microprocessor Development System: A tool for designing and debugging both hardware and software for microcomputer-based system. Microprocessor-Halt DMA: Data transfer is performed between the microcomputer s memory and a peripheral device either by completely stopping the microprocessor or by a technique called cycle stealing. Microprogramming: The microprocessor can use microprogramming to design the instruction set. Each instruction in the Instruction register initiates execution of a micro program stored typically in ROM inside the control unit to perform the required operation. Monitor: Consists of a number of subroutines grouped together to provide intelligence to a microcomputer system. This intelligence gives the microcomputer system the capabilities for debugging a user program, system design, and displays. Multiplexer: A hardware device which selects one of n input lines and produces it on the output. Multiprocessing: The process of executing two or more programs in parallel, handled by multiple processors all under common control. Typically each processor will be assigned specific processing tasks. Multitasking: Operating system software that permits more than one program to run on a single microprocessor. Even though each program is given a small time slice in which to execute, the user has the impression that all tasks (different programs) are executing at the same time. Multiuser: Describes a computer operating system that permits a number of users to access the system on a time-sharing basis Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 4

5 Nanomemory : Two-level ROM used in designing the control unit. Nested Subroutine: A commonly used programming technique in which one subroutine calls another subroutine Nibble: A 4-bit word. Non-inverting Buffer: Microprocessor Theory and Applications with 68000/68020 and Pentium Input is same as output. Current amplifier. Nonmaskable Interrupt: Occurrence of this type of interrupt cannot be ignored by microcomputer and even though interrupt capability of the microprocessor is disabled. Its effect cannot be disabled by instruction. Non-Multiplexed: A non-multiplexed microprocessor pin that assigns a unique function as opposed to a multiplexed microprocessor pin defining two functions on timeshared basis. Object Code: The binary (machine) code into which a source program is translated by a compiler, assembler, or interpreter. Ones Complement: Obtained by changing 1 s to 0 s, and 0 s to 1 s of a binary number. One-Pass Assembler: This assembler goes through the assembly language program once and translates the assembly language program into a machine language program. This assembler has the problem of defining forward references. See Two-Pass Assembler. Op Code (Operation Code): Part of an instruction defining the operation to be performed. Operand: A datum or information item involved in an operation from which the result is obtained as a consequence of defined addressing modes. Various operand types contain information, such as source address, destination address, or immediate data. Operating System:Typical resources include microprocessors, disks, and printers. Consists of a number of program modules to provide resource management. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 5

6 Page: Some microprocessors, divide the memory locations into equal blocks. Each of these blocks is called a page and contains several addresses. Parallel Operation: Any operation carried out simultaneously with a related operation. Parallel Transmission: Each bit of binary data is transmitted over a separate wire. Parity: The number of 1 s in a word is odd for odd parity and even for even parity Peripheral: An I/O device capable of being operated under the control of a CPU Examples include disk drives, keyboards, CRT s, printers, and modems. through communication channels Personal Computer: Low-cost, affordable microcomputer normally used by an individual for word processing and Internet applications. Physical Address Space: Address space is defined by the address pins of the microprocessor. Absolute Addressing: This addressing mode specifies the address of data with the instruction. Accumulator: Available with 8-bit microprocessors. Register used for storing the result after most ALU operations. Address: A unique identification number (or locator) for source or destination of data. An address specifies the register or memory location of an operand involved in the instruction. Addressing Mode: Address of source and destination operands in an instruction. The manner in which a microprocessor determines the effective. Address Register: A register used to store the address (memory location) of data. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 6

7 Address Space: The number of storage location in a microcomputer s memory that can be directly addressed by the microprocessor. The addressing range is determined by the number of address pins provided with the microprocessor chip. American Standard Code for Information Interchange (ASCII): It is commonly used with microprocessors for representing alphanumeric codes. Analog-to-Digital Converter (ADC): An 8-bit code Transforms an analog voltage into its digital equivalent. AND gate: The output is 1, if all inputs are 1; otherwise the output is 0. ASIC: Normally reduces the total manufacturing cost of a product by reducing chip count. Application Specific IC. Chips designed for a specific, limited application. Assembler: A program that translates an assembly language program into a machine language program. Assembly Language: A type of microprocessor programming language that uses a semi-englishlanguage statement Microprocessor Theory and Applications with 68000/68020 and Pentium Asynchronous Operation: The execution of a sequence of steps such that each step is initiated upon completion of the previous step. Asynchronous Serial Data Transmission: The transmitting device does not need to be synchronized with the receiving device. Autodecrement Addressing Mode: The contents of the specified microprocessor register are first decremented by n (1 for byte, 2 for 16-bit, and 4 for 32-bit) and then the resulting value is used as the address of the operand. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 7

8 Autoincrement Addressing Mode: The contents of a specified microprocessor register are used as the address of the operand first and then the register contents are automatically incremented by n (1 for byte, 2 for 16-bit, and 4 for 32-bit). Barrel Shifter: A specially configured shift register that is normally included in 32-bit microprocessors for cycle rotation. That is, the barrel shifter shifts data in one direction. Base address: An address that is used to convert all relative addresses in a program to absolute (machine) addresses Baud Rate: Rate of data transmission in bits per second. Binary-Coded Decimal (BCD): The representation of 10 decimal digits, 0 through 9, by their corresponding 4- bit binary number. Bit: A unit of information equal to one of two possible states (one or zero, on or off, true or false). An abbreviation for a binary digit Block Transfer DMA: A peripheral device requests the DMA transfer via the DMArequest line, which is connected directly or through a DMA controller chip to the microprocessor. The DMA controller chip completes the DMA transfer and transfers the control of the bus to the microprocessor. Branch: The branch instruction allows the computer to skip or jump out of program sequence to a designated instruction either unconditionally or conditionally (based on conditions such as carry or sign). Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 8

9 Breakpoint: Allows the user to execute the section of a program until one of the Break point conditions is met. It is then halted. The designer may then single step or examine memory and registers. Typically breakpoint conditions are program counter address or data references. Breakpoints are used in debugging assembly language programs. Buffer: A temporary memory storage device deigned to compensate for the different data rates between a transmitting device and a receiving device (for example, between a CPU and a peripheral). Current amplifiers are also referred to as buffers. Bus: A collection of wires that interconnects computer modules.the typical microcomputer interface includes separate buses for address, data, control, and power functions. Bus Arbitration: Bus operation protocols (rules) that guarantee conflict-free access to a bus. Arbitration is the process of selecting one respondent from a collection of several candidates that concurrently request service. Bus Cycle: The period of time in which a microprocessor carries out read or write operations. Cache Memory: A high speed, directly accessible, relatively small, semiconductor read write memory block used to store data instructions that the microcomputer may need in the immediate future. Increases speed by reducing the number of external memory reads required by the processor. Typical 32 and 64-bit microprocessors are normally provided with on-chip cache memory. Compact Disc (CD) Memory: Optical memory. Uses laser and stores audio information. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 9

10 Central Processing Unit (CPU): Have registersection, and control unit. CPU in a single chip is called microprocessor.the brains of a computer containing the ALU. Chip: An Integrated Circuit (IC) package containing digital circuits. CISC: Complex Instruction Set Computer. The Control unit is designed using Microprogramming. Contains a large instruction set. Difficult to pipeline compared to RISC. Clock: Timing signals providing synchronization among the various components in a microcomputer system. Analogous to heart beats of a human being. CMOS: Complementary MOS. Dissipates low power, offers high density and speed compared to TTL. Combinational Circuit: Output is provided upon application of inputs; contains no memory. Compiler: A program which translates the source code written in a high-level Programming language into machine language that is understandable to the processor Condition Code Register: It Contains information like carry, sign, zero, and overflow based on ALU operations. Control Unit: Microprocessor Theory and Applications with 68000/68020 and Pentium Part of the CPU; its purpose is to translate or decode instructions read (fetched) from the main memory into the Instruction Register Coprocessor: A companion microprocessor that performs specific functions such as floating - point operations independently from the microprocessor to speed up overall operations. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 10

11 Cycle Stealing DMA:The DMA controller transfers a byte of data between the microcomputer's memory and a peripheral device such as the disk by stealing a clock cycle of microprocessor. Data: Basic elements of information represented in binary form (that is, digits consisting of bits) that can be processed or produced by a microcomputer. Data represents any group of operands made up of numbers, letters, or symbols denoting any condition, value, or state. Typical microcomputer operand sizes include: a word, which typically contains 2 bytes or 16-bits; a long word, which contains 4 bytes or 32 bits; a quad word, which contains 8 bytes or 64 bits. Data Register: A register used to temporarily hold operational data being sent to and from a peripheral device. Debugger: A program that executes and debugs the object program generated by the assembler or compiler. The debugger provides a single stepping, breakpoints, and program tracing. Decoder: A chip, when enabled, selects one of 2" output lines based on n inputs. Digital to Analog (D/A) Converter: Converts binary number to analog signal. Diode: Two terminal electronic switch. Direct Memory Access (DMA): A type of inputjoutput technique in which data can be transferred between the microcomputer memory and external devices without the microprocessor's involvement. Directly Addressable Memory: The memory address space in which the microprocessor can directly execute programs. The maximum directly Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 11

12 addressable memory is determined by the number of the microprocessor's address pins. DRAM(Dynamic RAM): Stores data as charges in capacitors and therefore, must be refreshed milliseconds. Hence, requires refresh since capacitors can hold charges for a few circuitry. EAROM (Electrically Alterable Read-only Memory): Same as EEPROM or EPROM. Can be programmed one line at a time without removing the memory from its sockets. This memory is also called read-mostly memory since it has much slower write times than read times. Editor: A program that produces an error-free source program, written in assembly or high-level languages. Emulator: A hardware device that allows a microcomputer system to emulate (that is, mimic ) another microcomputer system. Encoder: Performs reverse operation of a decoder. Contains a maximum of 2" inputs and n outputs. EPROM (Erasable Programmable Read-only Memory): Can be programmed and erased all programs in an EPROM chip using ultraviolet light. The chip must be removed from the microcomputer system for programming. Exception Processing: Includes the microprocessor's processing states associated with interrupts, trap instructions, tracing, and other exceptional conditions, whether they are initiated internally or externally. Exclusive-OR: The output is 0, if inputs are same; otherwise; the output is 1. Exclusive-NOR: The output is 1, if inputs are same; otherwise, the output is 0. Extended Binary-Coded Decimal Interchange Code (EBCDIC): An 8-bit code commonly used with microprocessors for representing alphanumeric codes. Normally used by IBM. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 12

13 Firmware: Microprogram is sometimes referred to as firmware to distinguish it from hardwired control (purely hardware method). Flag(s): An indicator, often a single bit, to indicate some conditions such as trace, carry, zero, and overflow. Flash Memory: Utilizes a combination of EPROM and EEPROM technologies. Flip-Flop: One-bit memory. Used in cellular phones and digital cameras. FPGA: Field Programmable Gate Arrays. This chip contains several smaller individual logic blocks along with all interconnections Gate:Digital circuits which perform logic operations. Handshaking: Data transfer via exchange of control signals between the microprocessor and an external device. Hardware:The physical electronic circuits (chips) that make up the microcomputer system. Hardwired Control: Used for designing the control unit using all hardware. HCMOS: High speed CMOS. Provides high density and consumes low power. Hexadecimal Number System: Base-16 number system. High-Level Language: A type of programming language that uses a more understandable human-oriented language such as C. HMOS: High-density MOS reduces the channel length of the NMOS transistor and provides increased density and speed in VLSI circuits. Immediate Address: An address that is used as an operand by the instruction itself. Implied Address: An address is not specified, but is contained implicitly in the instruction. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 13

14 In-Circuit Emulation: The most powerful hardware debugging technique; Especially valuable when hardware and software are being debugged simultaneously. Index: A number (typically 8-bit signed or 16-bit unsigned) is used to identify a particular element in an array (string). The index value typically contained in a register is utilized by the indexed addressing mode. Indexed Addressing: The effective address of the instruction is determined by the Sum of the address and the contents of the index register. Used to access arrays. Index Register: A register used to hold a value used in indexing data, such as when a value is used in indexed addressing to increment a base address contained within an instruction. Indirect Address: A register holding a memory address to be accessed. Instruction: Causes the microprocessor to carry out an operation on data. A program contains instructions and data. Instruction Cycle: The sequence of operations that a microprocessor has to carry out while executing an instruction. Instruction Register (IR): A register storing instructions; typically 32 bits long for a 32-bit microprocessor. Instruction Set: Lists all the instructions that the microcomputer can execute. Interleaved DMA: Using this technique, the DMA controller takes over the system bus when the microprocessor is not using it. Internal Interrupt: Activated internally by exceptional conditions such as overflow and division by zero. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 14

15 Interpreter: A program that executes a set of machine language instructions in response to each high-level statement in order to carry out the function. Interrupt I/O: An external device can force the microcomputer system to stop executing the current program temporarily so that it can execute another program known as the interrupt service routine. Interrupts: A temporary break in a sequence of a program, initiated externally or Internally, causing control to jump to a routine, which performs some action while the program is stopped. I/O ( Input/Output): Describes that portion of a microcomputer system that exchanges data between the microcomputer system and an external device. I/O Port: A register that contains control logic and data storage used to connect a microcomputer to external peripherals. Inverting Buffer: Current amplifier. Performs NOT operation. Keyboard: Has a number of push button-type switches configured in a matrix form( rows x columns). Keybounce: When a mechanical switch opens or closes, it bounces (vibrates) for a small period of time (about ms) before settling down. Large-Scale Integration (LSI): An LSI chip contains 100 to 1000 gates. LED: Light Emitting Diode. Typically, a current of 10 ma to 20 ma flows at 1.7 to 2.4 drop across it. Logic Analyzer: A hardware development aid for microprocessor-based design; gathers data on the fly and displays it. Logical Address Space: All storage locations with a programmer s addressing range. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 15

16 Loops: A programming control structure where a sequence of microcomputer instructions are executed repeatedly (looped) until a terminating condition (result) is satisfied. Machine Code: Microprocessor Theory and Applications with 68000/68020 and Pentium A binary code (composed of 1 s and 0 s) that a microcomputer understands. Machine Language: A type of microprocessor programming language that uses binary or hexadecimal numbers. Macroinstruction: Commonly known as an instruction; initiates execution of a complete micro program. Example includes assembly language instructions. Macroprogram: The assembly language program. Mask: A pattern of bits used to specify (or mask) which bit parts of another bit pattern are to be operated on and which bits are to be ignored or masked out. Uses logical AND operation. Mask ROM: Programmed by a masking operation performed on the chip during the manufacturing process; its contents cannot be changed by user. Maskable Interrupt: Can be enabled or disabled by executing typically the interrupt instructions. Memory: Any storage device which can accept, retain, and read back data. Memory Access Time: Average time taken to read a unit of information from the memory. Memory Address Register (MAR): Stores the address of the data. Memory Cycle Time: Average time lapse between two successive read operations. Memory Management Unit (MMU): Hardware that performs address translation and protection functions. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 16

17 Memory Map: A representation of the physical locations within a microcomputer s addressable main memory. Memory-Mapped I/O: I/O ports are mapped as memory locations, with every connected device treated as if it were a memory location with a specific address. Manipulation of I/O data occurs in interface registers (as opposed to memory locations);hence there are no input (read) or output (write) instructions used in memory-mapped I/O. Microcode: A set of instructions called microinstructions usually stored in a ROM in the control unit of a microprocessor to translate instructions of a higher-level programming language such as assembly language programming. Microcomputer: Consists of a microprocessor, a memory unit, and an input/output unit. Microcontroller: Typically includes a microcomputer, timer, A/D (Analog to Digital) and D/A (Digital to Analog) converters in the same chip. Microinstruction: Most microprocessors have an internal memory called control memory. This memory is used to store a number of codes called microinstructions. These microinstructions are combined to design the instruction set of the microprocessor. Pipeline: A technique that allows a microcomputer processing operation to be broken down into several steps (dictated by the number of pipeline levels or stages) so that the individual step outputs can be handled by the microcomputer in parallel. Often used to fetch the processor s next instruction while executing the current instruction, which considerably speeds up the overall operation of the microcomputer. Overlaps instruction fetch with execution. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 17

18 Pointer: A storage location (usually a register within a microprocessor) that contains the address of (or points to) a required item of da+ta or subroutine. Polled Interrupt: A software approach for determining the source of interrupt in a multiple interrupt system. POP Operation: Reading from the top or bottom of stack. Port: A register through which the microcomputers communicate with peripheral. devices. Primary or Main Memory: Storage that is considered as part of the microcomputer. The microcomputer can directly execute all instructions in the main memory. The maximum size of the main memory is defined by the number of address pins in the microprocessor. Privileged Instructions: An instruction which can only be executed by the microprocessor in the supervisor (operating system) mode. Processor Memory: A set of microprocessor registers for holding temporary results when a computation is in progress. Program: A self-contained sequence of computer software instructions (sourcecode) that, when converted into machine code, directs the computer to perform specific operations for the purpose of accomplishing some processing task. Contains instructions and data. Program Counter (PC): A register that normally contains the address of the next instruction to be executed in a program. Programmed I/O: The microprocessor executes a program to perform all data transfers between the microcomputer system and external devices. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 18

19 PROM (Programmable Read-only Memory): Can be programmed by the user by using proper equipment. Once programmed, its contents cannot be altered. Protocol: A list of data transmission rules or procedures that encompass the timing, control, formatting, and data representations by which two devices are to communicate. Also known as hardware handshaking, which is used to permit asynchronous communication. PUSH Operation: Microprocessor Theory and Applications with 68000/68020 and Pentium Writing to the top or bottom of stack. Random Access Memory (RAM): Are volatile in nature (in other words, information is lost when power is removed).a read/write memory. RAMS (static or dynamic) Read-Only-Memory (ROM): A memory in which any addressable operand can be read from, but not written to, after initial programming. ROM storage is non volatile (information is not lost after removal of power). Reduced Instruction Set Computer (RISC): A simple instruction set is included. The RISC architecture maximizes speed by reducing clock cycles per instruction. The control unit is designed using hardwired control. Easier to implement pipelining. Register: A high-speed memory usually constructed from flip-flops that are directly accessible to the microprocessor. It can contain either data or a specific location in memory that stores word(s) used during arithmetic, logic, and transfer operations. Register Indirect: Uses a register which contains the address of data. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 19

20 Relative Address: An address used to designate the position of a memory location RISC: See Reduced Instruction Set Computer. in a routine or program. Routine: A group of instructions for carrying out a specific processing operation. Usually refers to part of a larger program. A routine and subroutine have essentially the same meaning, but a subroutine could be interpreted as a self-contained routine nested within a routine or program. Scalar Microprocessor: The is a scalar microprocessor. Provided with one pipeline. Allows execution rate of one clock cycle per instruction for most instructions. Scaling: Multiplying an index register by 1,2,4 or 8. Used by the addressing modes of typical 32- and 64-bit microprocessors. Schmitt Trigger: An analog circuit that provides high noise immunity. SDRAM: Control signals and address inputs are sampled by the SDRAM by a common clock. Synchronous DRAM. This chip contains several DRAMS internally. The Secondary Memory Storage: An auxiliary data storage device that supplements the main (primary) memory of a microcomputer. It is used to hold programs and data that would otherwise exceed the capacity of the main memory. Although it has a much slower access time, secondary storage is less expensive. Examples include floppy and hard disks. Sequential Circuit: Combinational circuit with memory PUSH Operation: Microprocessor Theory and Applications with 68000/68020 and Pentium Writing to the top or bottom of stack. Random Access Memory (RAM): A readwrite memory. RAMS (static or dynamic) are volatile in nature (in other words, information is lost when power is removed). Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 20

21 Read-Only-Memory (ROM): A memory in which any addressable operand can beread from, but not written to, after initial programming. ROM storage is non volatile information is not lost after removal of power). Reduced Instruction Set Computer (RISC): A simple instruction set is included. The RISC architecture maximizes speed by reducing clock cycles per instruction. The control unit is designed using hardwired control. Easier to implement pipelining. Register: A high-speed memory usually constructed from flip-flops that are directly accessible to the microprocessor. It can contain either data or a specific location in memory that stores word(s) used during arithmetic, logic, and transfer operations. Register Indirect: Uses a register which contains the address of data. Relative Address: An address used to designate the position of a memory location in a routine or program. RISC: See Reduced Instruction Set Computer. Routine: A group of instructions for carrying out a specific processing operation. Usually refers to part of a larger program. A routine and subroutine have essentially the same meaning, but a subroutine could be interpreted as a self-contained routine nested within a routine or program. Scalar Microprocessor: The is a scalar microprocessor. Provided with one pipeline. Allows execution rate of one clock cycle per instruction for most instructions Scaling: Multiplying an index register by 1,2,4 or 8. Used by the addressing modes of typical 32- and 64-bit microprocessors Schmitt Trigger: An analog circuit that provides high noise immunity. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 21

22 SDRAM: Control signals and address inputs are sampled by the SDRAM by a common clock. Synchronous DRAM. This chip contains several DRAMS internally. The Secondary Memory Storage: An auxiliary data storage device that supplementsthe main (primary) memory of a microcomputer. It is used to hold programs and data that would otherwise exceed the capacity of the main memory. Although it has a much slower access time, secondary storage is less expensive. Examples include floppy and hard disks. Sequential Circuit: Combinational circuit with memory Superscalar Microprocessor: The Pentium is a superscalar microprocessor. Microprocessor Theory and Applications with 68000/68020 and Pentium Provided with more than one pipeline and executes More than one instruction per clock cycle. Super visor State: When the microprocessor processing operations are conducted at a higher privilege level, it is usually in the supervisor state. An operating system typically executes in the supervisor state to protect the integrity of basic system operations from user influences. Synchronous Operation: Operations that occur at intervals directly related to a clock period. Synchronous Sequential Circuit: The present outputs depend on the present inputs and the previous states stored in flip-flops Synchronous Serial Data Transmission: Data is transmitted or received based on a clock signal. Tracing:(Allows single stepping.) A dynamic diagnostic technique permits analysis debugging) of the program s execution. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 22

23 Transistor: Electronic switch; performs NOT; current amplifier. Tristate Buffer: This chip is typically enabled by a control signal to provide logic 0 or 1 outputs. This type of buffer can also be disabled by the control signal to place it in a high-impedance state. Has three output states: logic 0, 1, and a high-impedance state Two s Complement: The two s complement of a binary number is obtained by replacing each 0 with a 1 and each 1 with a 0 and adding one to the resulting number Vectored Interrupts: A device identification technique in which the highest Priority device with a pending interrupt request forces program execution to branch to an interrupt routine to handle exception processing for the device. Very Large Scale Integration (VLSI): a VLSI chip contains more than 1000 gates. More commonly, a VLSI chip is identified by the number of transistors rather than the gate count. Virtual Memory: An operating system technique that allows programs or data to exceed the physical size of the main, internal, directly accessible memory of the microcomputer. Program or data segment pages are swapped from external disk storage as needed. The swapping is invisible (transparent) to the programmer. Therefore, the programmer does need not to be concerned with the actual physical size of internal memory while writing the code. Word: The bit size of a microprocessor refers to the number of bits that can be Processed simultaneously by the basic arithmetic and logic circuits of the microprocessor. A number of bits taken as a group in this manner is called a word Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 23

24 UNIT I THE 8086 PROCESSOR SOFTWARE ASPECTS PART A (TWO MARKS) 1. What is Microprocessor? Give the power supply & clock frequency of 8085 A microprocessor is a multipurpose, programmable logic device that reads binary instructions from a storage device called memory accepts binary data as input and processes data according to those instructions and provides result as output. The power supply of 8085 is +5V and clock frequency in 3MHz 2. List few applications of microprocessor-based system. It is used: For measurements, display and control of current, voltage, For temperature, pressure, etc. For traffic control and industrial tool control. For speed control of machines. 3. What are the modes in which 8086 can operate? The 8086 can operate in two modes and they are minimum (uniprocessor) mode and maximum (multiprocessor) mode. 4. What is the data and address size in 8086? The 8086 can operate on either 8-bit or 16-bit data. The 8086 uses 20 bit address to access memory and 16-bit address to access 1/0 devices. 5. Write the flags of 8086? The 8086 has nine flags and they are Carry Flag (CF) Overflow Flag (OF) Parity Flag (PF) Trace Flag (TF) Auxiliary carry Flag (AF) Interrupt Flag (IF) Zero Flag (ZF) Direction Flag (DF) Sign Flag (SF) Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 24

25 6. What are the interrupts of 8086? The interrupts of 8086 are INTR and NMI. The INTR is general maskable interrupt and NMI is non-maskable interrupt. 7. Write the special functions carried by the general purpose registers of 8086?(Nov/Dec 2008) The special functions carried by the registers of 8086 are the following. Register Special function AX 16-bit Accumulator AL 8-bit Accumulator BX Base Register CX Count Register DX.Data Register 8. What is pipelined architecture? (Nov/Dec 2004) In pipelined architecture the processor will have number of functional units and the execution time of functional units is overlapped. Each functional unit works independently most of the time. 9. What are the functional units available in 8086 architecture? The bus interface unit and execution unit are the two functional units available in 8086 architecture. 10. List the segment registers of 8086? The segment registers of 8086 are Code segment, Data segment, Stack segment and Extra segment registers. 11. What is interrupt I/0?(Nov/Dec 2005) If the I/0 device initiate the data transfer through interrupt then the I/0 is called interrupt driven I/ Compare Procedure & Macro? (April/May 2006) PROCEDURE Accessed by CALL & RET instruction MACRO Accessed during assembly with name given during program execution to macro when Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 25

26 Machine code for instruction is put only once in the memory With procedures less memory is required Parameters can be passed in registers, memory locations or stack defined Machine code is generated for instruction each time when macro is called with macro more memory is required Parameters passed as part of statement which calls macro 13. What is linker? (April/may 2005) A linker is a program used to join together several object files into one large object file. For large programs it is more efficient to divide the large program modules into smaller modules. Each module is individually written, tested & debugged. When all the modules work they are linked together to form a large functioning program. 14. Explain ALIGN & ASSUME? The ALIGN directive forces the assembler to align the next segment at an address Divisible by specified divisor. The format is ALIGN number where number can be 2, 4, 8 or 15. Example ALIGN 8. The ASSUME directive assigns a logical segment to a physical segment at any given time. It tells the assembler what address will be in the segment registers at execution time. Example ASSUMES CS: code, DS: data, SS: stack 16. Explain PTR & GROUP? A program may contain several segments of the same type. The GROUP directive collects them under a single name so they can reside in a single segment, usually a data segment. The format is Name GROUP Segname,..Seg-name. PTR is used to assign a specific type to a variable or a label. It is also used to override the declared type of a variable. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 26

27 17. Explain PROC & ENDP? PROC directive defines the procedures in the program. The procedure name must be unique. After PROC the term NEAR or FAR are used to specify the type of procedure. Example FACT PROC FAR. ENDP is used along with PROC and defines the end of the procedure. 18. Explain SEGMENT & ENDS? An assembly program in.exe format consists of one or more segments. The starts of these segments are defined by SEGMENT and the end of the segment is indicated by ENDS directive. Format Name SEGMENT Name ENDS 19. Explain TITLE & TYPE? The TITLE directive helps to control the format of a listing of an assembled program. It causes a title for the program to print on line 2 of each page of the program listing. Maximum 60 characters are allowed. Format TITLE text. TYPE operator tells the assembler to determine the type of specified variable in bytes. For bytes the assembler gives a value 1, for word 2 & double word Define SOP? The segment override prefix allows the programmer to deviate from the default segment Eg : MOV CS : [BX], AL 21. Define variable? A variable is an identifier that is associated with the first byte of data item. In assembly language statement: COUNT DB 20H, COUNT is the variable. 22. What are procedures? Procedures are a group of instructions stored as a separate program in memory and it is called from the main program whenever required. The type of Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 27

28 procedure depends on where the procedures are stored in memory. If it is in the same code segment as that of the main program then it is a near procedure otherwise it is a far procedure. 23. Explain the linking process? A linker is a program used to join together several object files into one large object file. The linker produces a link file which contains the binary codes for all the combined modules. It also produces a link map which contains the address information about the link files. The linker does not assign absolute addresses but only relative address starting from zero, so the programs are re locatable & can be put anywhere in memory to be run. 24. Explain about passing parameters using registers with example? Procedures process some data or address variable from the main program, for processing it is necessary to pass the address variables or data. This is called passing parameters to procedures. In passing parameters using registers the data to be passed is stored in registers & these registers are accessed in the procedure to process the data. CODE SEGMENT MOV AL, DATA CALL PRO1 PRO1 PROC NEAR MOV INPUT, AL RET PRO1 ENDP CODE ENDS 25. What is a recursive procedure? A recursive procedure is a procedure, which calls itself. Recursive procedures are used to work with complex data structures called trees. If the procedure is called with N=3, then the N is decremented by 1 after each procedure CALL and the procedure is called until N= What are libraries? Library files are collection of procedures that can be used in other programs. These procedures are assembled and compiled into a library file by the LIB program. The library file is invoked when a program is linked with Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 28

29 linker program. when a library file is linked only the required procedures are copied into the program. Use of library files increase s/w reusability & reduce s/w development time. 27. What are Macros?(Nov/Dec 2004) Macro is a group of instruction. The macro assembler generates the code in the program each time where the macro is called. Macros are defined by MACRO & ENDM directives. Creating macro is similar to creating new opcodes that can be used in the program INIT MACRO MOV AX, data MOV DS MOV ES, AX ENDM 28. How do 8086 interrupts occur? An 8086 interrupt can come from any of the following three sources External signals Special instructions in the program Condition produced by instruction 29. What are the 8086 interrupt types? Dedicated interrupts Type 0: Divide by zero interrupt Type 1: Single step interrupt Type 2: Non maskable interrupt Type 3: Breakpoint Type 4: Overflow interrupt Software interrupts Type What is interrupt service routine?(may/june 2007) Interrupt means to break the sequence of operation. While the CPU is executing a program an interrupt breaks the normal sequence of execution of instructions & diverts its execution to some other program. This program to which the control is transferred is called the interrupt service routine. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 29

30 31. Define BIOS? The IBM PC has in its ROM a collection of routines, each of which performs some specific function such as reading a character from keyboard, writing character to CRT. This collection of routines is referred to as Basic Input Output System or BIOS. 32. What is the purpose of segment registers in 8086? There are 4 segment registers present in They are Code Segment (CS ) register Data Segment (DS ) register Stack Segment (SS ) register Extra Segment (ES ) register The code segment register gives the address of the current code segment. ie. It will points out where the instructions, to be executed, are stored in the memory. The data segment register points out where the operands are stored in the memory. The stack segment registers points out the address of the current stack, which is used to store the temporary results. If the amount of data used is more the Extra segment register points out where the large amount of data is stored in the memory. 33. Define pipelining?(nov/dec 2004) In 8086, to speedup the execution of program, the instructions fetching and execution of instructions are overlapped each other. This technique is known as pipelining. In pipelining, when the n th instruction is executed, the n+1 th instruction is fetched and thus the processing speed is increased. 34. Discuss the function of instruction queue in 8086? In 8086, a 6-byte instruction queue is presented at the Bus Interface Unit (BIU). It is used to pre fetch and store at the maximum of 6 bytes of instruction code from the memory. Due to this, overlapping instruction fetch with instruction execution increases the processing speed. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 30

31 35. What is the maximum memory size that can be addressed by 8086? In 8086, an memory location is addressed by 20 bit address and the address bus is 20 bit address and the address bus is 20 bits. So it can address up to one mega byte (2^20) of memory space. 36. What are the predefined interrupts in 8086?(Nov/Dec 2005) The various predefined interrupts are, DIVISION BY ZERO (type 0) Interrupt. SINGLE STEP (type 1) Interrupt. NONMASKABLE (type2) Interrupt. BREAK POINT (type 3) Interrupt. OVER FLOW (type 4) Interrupt. 37. What are the different flag available in status register of 8086? There are 6 one bit flags are present. They are, AF - Auxiliary Carry Flag CF - Carry Flag OF - Overflow Flag SF - Sign Flag PF - Parity Flag ZF - Zero Flag 38. List the various addressing modes present in 8086? There are 12 addressing modes present in They are, Register and immediate addressing modes Register addressing modes Immediate addressing mode Memory addressing modes. Direct addressing modes Register indirect addressing modes Based addressing modes Indexed addressing modes Based Indexed addressing modes String addressing modes I/O addressing modes Direct addressing mode Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 31

32 Indirect addressing mode Relative addressing mode Implied addressing mode 39. How single stepping can be done in 8086? By setting the Trace Flag (TF) the 8086 goes to single-step mode. In this mode, after the execution of each instruction s 8086 generates an internal interrupt and by writing some interrupt service routine we can display the content of desired registers and memory locations. So it is useful for debugging the program. 40. What are the functions of bus interface unit (BIU) in 8086?(Nov/Dec 2008) Fetch instructions from memory. Fetch data from memory and I/O ports. Write data to memory and I/O ports. To communicate with outside world. Provide external bus operations and bus control signals. 41. What is the clock frequency of 8086? Internal clock Frequency 5 MHz 8MHz 4MHz External Clock Frequency 15MHZ 24MHZ 12MHZ 42. What are the three classifications of 8086 interrupts?(may/june 2007) Predefined interrupts User defined Hardware interrupts User defined software interrupts. 43. What is Key bouncing? Mechanical switches are used as keys in most of the keyboards. When a key is pressed the contact bounce back and forth and settle down only after a small time delay (about 20ms). Even though a key is actuated once, it will appear to have been actuated several times. This problem is called Key Bouncing.. Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 32

33 44. Define swapping in? The portion of a program is required for execution by the CPU, it is fetched from the secondary memory and placed in the physical memory. This is called swapping in of the program. 45. What is an instruction set and enlist the types of instructions? The instruction set is indeed one of the key features of computer architecture, defining and describing the capabilities of any computing system, including microprocessors. Types as following, Data movement instruction Integer arithmetic and logic instructions Shift and rotate instructions Control transfer instructions Bit manipulation instructions System control instruction Floating-point instruction Special function unit instruction. 46. Enlist the different data-types supported by a microprocessor? A typical set of integer data formats as practiced in modern microprocessor, Signed and unsigned ASCII characters,8 bits each Packed and unpacked binary coded decimal(bcd) numbers,4 bits each There are two ways of ordering the byte addresses within a word: Little-endian Big-endian 47. Enlist the different instruction formats in a microprocessor? Instruction formats vary considerably among different microprocessors. In some systems, instructions are formed in units of bytes, in some in units of 16- bit half words (however, in some systems they are called words ), and in others in units of 32-bit words. The basic information included in an instruction format consists primarily of: Instruction opcode Addresses of operands Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 33

34 48. What do you mean by addressing mode? Enlist the different types of addressing mode. The address of the operand in memory is stored in one of registers that is addressing modes. Register addressing modes Immediate addressing modes Direct addressing modes Register indirect addressing modes Register indirect with post increment Register indirect with pre decrement Register indirect with displacement 49. What are the advantages & disadvantages of segmentation? Advantages: Segmentation supports well-structured software, since segments can contains meaningful information units. Supports more compact code, since reference within a segment can be shorter. Segmentation supports efficient typing of data, thus contribute g to the narrowing of the semantic gap. Disadvantages: Increased hardware complexity Execution time overhead in handling segmentation Extra memory need for segmentation tables Added memory fragmentation for small segments. 50. What are the four types of pipeline stages? The four stages of pipelines are: Fetch Decode Execute Write back Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 34

35 PART B BIG QUESTIONS 1. Describe with a neat block diagram the internal architecture and working of all the internal units of 8086 microprocessor. Block diagram Special purpose registers General data register Segment registers Pointers and index registers Bus interface unit Execution unit Memory segmentation Explanation about each block in the block diagram 2. Explain the addressing modes of 8086 with example? Nov/Dec 05. The address of the operand in memory is stored in one of registers that is addressing modes. There are 12 addressing modes present in They are, Register and immediate addressing modes Register addressing modes Immediate addressing mode Memory addressing modes. Direct addressing modes Register indirect addressing modes Based addressing modes Indexed addressing modes Based Indexed addressing modes String addressing modes I/O addressing modes Direct addressing mode Indirect addressing mode Prepared by P. SELVAN M.E, AP/ECE, Chettinad Tech, Karur Page 35