Studied by 13 people
performs fetch and execute
directly accessed by main memory
CU
ALU
registers and buses
performs decode stage
sends control signals
controls the flow of the cycle
arithmetic logic unit
performs logic and arithmetic calculations
using ACC
pc
acc
cir
mar
mdr
program counter
holds the address of the next instruction to be fetched from memory
adress bus: pc → MAR (unidirectional)
data bus: MDR/CIR/IO devices (bidirectional)
control bus : carry timing signals (bidirectional)
pc holds next instruction address
address copied to MAR using address bus
data copied from MAR to MDR
data copied through data bus
to CIR
pc value increments by one to point to next instruction
data held at CIR to be decoded by CU
data passed on the CPU
CU checks that IO devices are ready
if they are, instruction data is passed onto alu for execute
ALU performs logic and arithmetic calculations required by the instruction
ACC temporarily stores values for the ALU
one set of ALU, CU and register and buses
can also be dual or quad core
when the clock speed is too high for the computer
can cause overheating
gps
security systems
lighting systems
washing machines
motor vehicles
can be small and portable
simple interface
can be remotely controlled
consume little power
relatively cheap
needs a specialist to troubleshoot issues
difficult to upgrade
can be hacked
can be thrown away easily if out of date/ wasteful
