3. hardware Flashcards
what does the CPU do
the CPU proceses instructions and data that are input into the computer so that the result can be output
what is the microprosesser
the microporocessor is a type of intergrated circuit on a single chip
what are the units of the cpu
- arithematic logic unit- responsible for carying out mathamatical calculation
- control unit- manages the other components
what are the registers of the cpu
-PC:
- MAR:
- cir
- MDR
- ACC
pc
-PC: holds the address (memory location) of the next instruction to be fetched.
MAR
s also used when reading and writing data to and from RAM. The MDR will contain the data to be written to RAM, or the data that has just been read from RAM.
CIR
holds the instruction which is currently being decoded or executed.
ACC
is used to hold the data being worked on by the ALU
what is the control bus
The control bus carries control signals from the Control Unit to other components of the CPU. and read and write signals
what is the adress bus
the adress bus carries adresses from the memory adress register to the RAM, to indicade wgich adress will be selected. only 1 direction
what is the data bus
a data bus carries data from the memory data register to the RAM during a write operation, the data bus carried data from the RAM to the memory data register during a read operation. bidirectional
explain the fetch decode execute cycle
-the pc contains the adress of the next instruction
- the contents of the PC are copies to the MAR
- the pc is incrimented by 1 so it still points to the next instruction
- the adress bus carries the value in the MAR to the RAM
- the control bus sends a ‘read’signal to RAM
- the data bus carries the contents of the desired RAM adress froom the RAM to the MDR
- the contents of MDR is sopies to the CIR
- the control unit decodes data
- ALU executes
what is the clock speed of the cpu
- usually measured in GHz
-determains the number of cycles a CPU can perform each second
more speed can generate more energy and heat
what are the cores of the cpu
a processer within the cpu. only 1 core can occur at a time.
what is the cache of the CPU
the cache is extremely fast memory that is located within the CPU. it is used to store temporary copies of the data in most commonly accessed RAM locations.
purpose of instructions set for a CPU
- An instruction set is a list of all the commands
that can be processed by a CPU and the
commands are machine code
the purpose and characteristics of an
embedded system and identify devices in which
they are commonly used
An embedded system is used to perform a
dedicated function, e.g. domestic appliances,
cars, security systems, lighting systems or
vending machines. This is different to a general
purpose computer that is used to perform many
different functions, e.g. a personal computer (PC)
or a laptop
barcode scanner
shine a light at barcode and measure the reflected light to read the data- quick, accurate, efficient
digital camera
uses a image sensore to measure light and take phototgraph, which is stored digitally on a device.
keyboard
allows users to type text and numeric data- reduced number of mistakes, limited operations
microphone
allows sound to be input. the sound can be playback at any time
mouse
control curser on screen
QR code scanner
represents small text characters using black and white pattern. store URLs. quick, requires internet, nfinate patterns
touch screen
input data using finger- user friendly, select from a small range of options.
resistive- uses very thin metal sheets over screen, pressure of contact complete ciruit
capacitive- transparent layer sensitive to static electrical charge in the human body
infrared- grid of infra red light over the screen. this grid is ivisable to users. light beams are broken info is detected.
2D scanners
documents are laid flat on the device and light is used to scan the document into a digital image. OCR software scan texts.
3D scanners
canning an object using lasers to measure the dimensions (height, width, depth) of an object. The laser detects details about the shape of the object and converts this into digital data
what is a actuator
An actuator takes a digital signal and outputs it as a physical movement.
eg: automatic door system.
what is a 3d printer
building up thin layers of material, layer by layer, until the object is complete. Objects are usually created from plastic filaments (such as ABS or PLA plastic) or from resin.