Embedded Computers PDF

Embedded Computers An embedded computer is a special-purpose computer that functions as a component in a larger product Consumer Home Automation Process Controllers Computer Devices...

Embedded Computers An embedded computer is a special-purpose computer that functions as a component in a larger product Consumer Home Automation Process Controllers Computer Devices Automobiles Electronics Devices and Robotics and Office Machines Mobile and digital Thermostats Antilock brakes Remote monitoring Keyboards telephones Sprinkling systems Engine control systems Printers Digital televisions Security modules Power monitors Faxes Cameras monitoring systems Airbag controller Machine Copiers Video recorders Appliances Cruise control controllers DVD players and Lights Medical devices recorders Answering machines Page 26 Discovering Computers 2011: Living in a Digital World 27 Chapter 1 Embedded Computers Page 26 Discovering Computers 2011: Living in a Digital World 28 Figure 1-28 Chapter 1 Advantages and Disadvantages of Using Computers Advantages of Disadvantages of Using Computers Using Computers Speed Health Risks Reliability Violation of Privacy Consistency Public Safety Storage Impact on Labor Force Communications Impact on Environment Discovering Computers 2011: Living in a Digital World Pages 9 - 10 9 Chapter 1  Classification of Memory Unit Storage Capacity Internal Processor Registers, Cache Memory Primary Memory RAM, ROM Secondary Memory Hard Disk, Floppy etc. Access COST time Cache Memory Inside a microprocessor Very very expensive Manufactured to match the speed of processor. Gives better access time. Saves time Like a library system Registers High speed special purpose memory units. Registers are controlled by Control Unit. Generally, they hold the intermediate results. Works like a cash register of a shop keeper. Some important Registers Program counter (PC): keeps track of the next instruction to be executed. Instruction Register (IR): holds the instruction to be decoded by the control unit. Memory Address Register (MAR): holds the address of the next location in RAM to be accessed. Some important Registers…... Memory Buffer Register (MBR): stores data either coming to the CPU or being transferred by the CPU. Accumulator (ACC): A general purpose register used for storing temporary results. Data Register (DR): stores operands. Input/Output Register: communicated with the input/output devices. Buses What is a bus?  Channel that allows devices inside and attached to the computer to communicate with each other  A collection of wires which connects together the internal components of the computer  Moves data around the system  From Input devices to CPU  CPU to Memory  Memory to Output devices  Works Like a highway  Bits travel along the highway  Bus width determines number of Buses  kinds of system bus Data bus  Carries actual data bits (information)  Moves data among computer system components Address bus  Transfers locations where data should be sent  Carries the bits of a memory address Control bus  Carries status information, like commands, command responses, status codes and similar messages System Bus