1.1 System Architecture Flashcards
What is an embedded system?
A computer designed for a dedicated function inside a larger device
What is the clock speed?
It is the number of instructions a processer can carry out per second
Why are Embedded systems efficient?
They are dedicated to a single task
Why does an increasing number of cores increase the speed of the CPU?
More cores a CPU has, more instructions can be carried out at once (multitasking)
What is cache?
Small component that stores frequently stored data
Why does a larger cache increase the speed of a computer?
Gives the CPU faster access to more data
Where does the CPU fetch instructions from?
RAM
Where does the CPU copy memory address to?
MAR
When does the PC become incremented?
When fetching an instruction?
What is the purpose of the CU?
Sends timing signals
Sends Control signals
Where are the instructions executed?
In the CU
What is a register?
A small amount of high-speed random access memory contained within the processor
What is the purpose of the program counter?
Holds the memory address of the next instruction to be fetched
What is the purpose of the ALU?
Does all the calculations and logic operators
What is the purpose of the Accumulator?
Holds the result of any calculations of the ALU
What is the purpose of the MAR?
Holds the address about to be used by the CPU
What is the purpose of the MDR?
Holds the actual data or instruction being processed by the CPU
What is the purpose of the Address bus?
Carries memory addresses from the processer to other components
What is the purpose of the Data bus?
Carries the actual data data between the processor and other components
What is the purpose of the Control bus?
Carries control signals from the processer to other components.
Also carries the clock’s pulses
What is a general purpose computer?
A computer designed to perform more than one task
What is a computer?
An electronic device that takes an input; processes data and delivers and output
What is the purpose of the CPU?
To fetch, decode and execute instructions
What is the purpose of the ALU?
Responsible for arithmetic calculations
Responsible for logical decisions
What are the key characteristics of the Von Neumann Architecture?
Central process uniting Single Control Unit Arithmetic Logic Unit Onboard Cache Internal Clock
What is the Von Neumann structure based on?
Based on the concept of the stored-program concept
What is the clock speed measure in?
Hz
What happens if the clock speed increases?
More fetch-decode-execute cycles can happen - as a result leads to improved efficiency
Where is the cache?
Near the CPU
What is a core?
A complete copy of the CPU
What is a quad-core processer?
Has 4 separate processing units each with its own: Accumulator ALU Registers Control Unit etc.
What are the benefits of having a CPU with multiple cores?
Have more power to run multiple programs at the same time
Why does doubling the number of cores simply not double the overall speed?
CPU cores have to communicate with each other, this takes time
Many programs are not designed to make use of multiple cores
What are the properties of embedded systems?
Lower power consumption
Small size
Rugged operating system
Low cost per unit
What are some examples of embedded systems?
Traffic light
Domestic appliances
Factory equipment
Hospital equipment
