Introduction to computing. Human vs Computer. Basic Concepts. Microprocessor in a computer board (Mother Board)

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Cameron Juniper Harper
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Introduction to computing The Microprocessor is the Brain of the computer. Like brain a processor can process/compute the information collected from the world.

1 Introduction to computing The Microprocessor is the Brain of the computer. Like brain a processor can process/compute the information collected from the world. More formally, microprocessor is a programmable integrated device (silicon chip) that has computing & decision making capabilities Communicates & operates in binary numbers 0 &, called bits (digital) Has a fixed set of instructions in the form of binary patterns machine language Human vs Computer Human Thinking/Computing Eating/breathing Processing Unit: Brain Computer Processing/Computing Supplying Electrical Power Processing Unit: Central Memory: Brain Processing Unit () Memory: RAM, ROM, Disk, CD Input Organs: Eye, Ear, Skin, ROM,.. Output Organs: Mouth (Voice), Input Devices: Keyboard, Mouse, Hand Sensors, Body and Soul (Mind) Output Devices: Monitor, Printer,. Hardware and Software Basic Concepts Microprocessor in a computer board (Mother Board) Microcomputer a computer with a microprocessor as its. Includes memory, etc. Microprocessor silicon chip which includes ALU, register circuits & control circuits Microcontroller silicon chip which includes microprocessor, memory & in a single package. Digital signal processor (DSP) - microprocessor optimized for digital signal processing.

2 Microprocessors Types of microcomputers Application Reprogrammable microprocessors (General-purpose) Embedded microprocessors and microcontrollers complexity CISC (Complex Set Computers) RISC (Reduced Set Computers) Application-Specific Processors (ASIPs) Processors with instruction-sets tailored to specific applications or application domains Pluses: Minuses: instruction-set generation as part of synthesis customization yields lower area, power etc. higher h/w & s/w development overhead design, compilers, debuggers higher time to market 6 Evolution of The Computers Evolution of The Computers Evolution of the computers has been characterized by increasing processor speed, decreasing component size, increasing memory size, and increasing capacity and speed. Since the size of the microprocessors become smaller, the distance between the components decreases and the speed increases. However, the important gain in the speed has been obtained by changing the architecture of the microprocesors including pipelining and parallel computing. A critical issue is to balance the performance of the several components, so that the gains in one area should not be lost by a lag in the other areas. In particular, the procesor speed has increased more rapidly than the memory access time. So there are several techniques to compansate this mismatch such as caches, larger data paths from memory to the microprocessors and more intelligent chips. 7 8

3 Computer Input/Output Main Memory Microprocessor Hardware System Interconnection Central Processing Unit Registers ALU Interconnection Control Unit 9 0 Computer Architectures: von Neumann architecture + memory Memory holds data, instructions. Central processing unit () fetches instructions from memory. registers help the operations: program counter (PC), instruction register (IR), general-purpose registers, etc. Execution occurs in a sequential fashion memory data 00 PC 00 ADD r,r,r IR ADD r,r,r

Harvard architecture von Neumann vs. Harvard Harvard can t use self-modifying code. data memory data PC Harvard allows two simultaneous memory fetches.

4 Harvard architecture von Neumann vs. Harvard Harvard can t use self-modifying code. data memory data PC Harvard allows two simultaneous memory fetches. Most DSPs use Harvard architecture for streaming data: greater memory bandwidth; program memory data Microcomputer Architecture Memory 8 bit Word length word instruction word instruction System Bus wires connecting memory & to microprocessor Bus Unidirectional Identifying peripheral or memory location Data Bus Bidirectional Transferring data Control Bus Synchronization signals Timing signals Control signal 6KByte FFFE FFFF Word: no. of bits microprocessor recognizes and processes at a time ( - 6bit ). : combination of bit patterns with specific meaning known to microprocessor. : Set of all instructions. 6

Basic Working Principle of Microprocessors Architecture s are stored sequentially in memory Microprocessor es instruction from memory Decodes instruction Executes instruction PC: counter IR :

5 Basic Working Principle of Microprocessors Architecture s are stored sequentially in memory Microprocessor es instruction from memory Decodes instruction Executes instruction PC: counter IR : register MAR: Memory register MBR: Memory buffer register AR: register BR: buffer register PC IR MAR MBR BUS The processing required for a single instruction is called instruction cycle. Execution Unit AR BR 7 8 Types of s Processor-Memory : Data may be transferred from processor to the memory or memory to the processor Processor- : Data may be transferred to or from a peripheral Example : Assume that a processor includes a single data register called accumulator (AC). Both instructions and data is 6bits long. bits of instruction is the opcode and the other bits determine the operand. device by transferring between the processor and module Data Processing: The processor may perform arithmetic or logic operations on data Control : An instruction may change the sequence of the instruction execution (jump, subroutine call) Opcode S 0 format Magnitude Integer format Opcodes Load AC from memory 000 Store AC to memory 9 00 Add to AC to memory 0

6 Cycle State Diagram In the previous example an addition and writing the result have been accomplished in three steps with each instruction consists a fetch cycle and an execution cycle. There may be more complex instructions which executes similar operations with fewer instruction cycles and more reference may be included. Example : ADD B,A instruction in PDP-, stores the sum of the contents of memory locations B and A in the memory addres A. Then in the instruction cycle: ADD instruction Read the content of A to processor Read the content of B to processor (at least registers) Add two values Write the result to the memory location A complete next instruction Decoding Store results Forvectoror string data operands Data s Example Cycles In order to provide an efficient processing, the instruction cycle can be interrupted by the memory or the modules. This is necessary for the modules which are much more slower than the microprocessor. Suppose that microprocessor is sending data to a printer. The microprocessor must wait idle until the printer finishes its job. Command END Command handler END Without s With s 6

7 Cycle State Diagram (Updated) s complete next instruction No interrupt Decoding Forvectoror string data operands There may be more than one interrupt sources. What happens if interrupt Y occurs while microprocessor is executing the interrupt X? Handler X Handler X Handler Y Check Store results Data Handler Y Sequential interrupt processing Nested interrupt processing 6 Architecture of Intel Microprocessors Basic Internal Architecture pipelining Normal operation of 808 (no pipelining) up Bus Decode Idle Execute Decode Idle Execute Beginning with 8086 and

Central Processing Unit (CPU)

Central Processing Unit (CPU) CPU is the heart and brain It interprets and executes machine level instructions Controls data transfer from/to Main Memory (MM) and CPU Detects any errors In the following