Ohne Titel

Seite 1

Seite 2

embedded systems

whats is an embedded computer system?

a computer system that forms part of an electronic device

they are found in many household devices such as watches,telephones,televsions,washig machine

larger and more complex systems

computer controlled

embedded computer systems

CPU

cpu carried out all the processing for the computer system by following all the instructions given to i .

follows the fetch-execute-decode cycle

fetch program instructions

execute program instructions

decode program instructions

what is the purpose of the processor?

clock speed is measured in hertz (number of cycles per second)

the processor is the brains of the computer system

it processes data ad instructions

carried out instructions (executes them)

what is a processor?

arithmetic and logic unit- carries out the calculations and logicla decisoins required by a program instruction (for example addition,subtraction and comparisons such as equal to, greater than or less than.

control unit -this is responsible for decoding the instructions and sendingf out signals to control how data moves around the parts of the cpu and memory to execute these instructions.

wokrs with the cpu to control the flow of the data within the system and decode instructions

buses

what does a bus do in a cpu

it is a communication channel through which data can be moved

they enable data and control signals move around the cpu and memory.

three types of bus

data bus-carries data between the cpu and memory

control bus-carries control signals around the cpu and memory

address bus- carries memory addresses for locations to be read from or written to

data bus

bi directional (two way)

data can be written/read

address bus

it is one direction -(uni-directional)

the processor generates an address

all data/instructions are returned on the data bus

register-program counter(pc) and memory address register (mdr)