FDE Cycle

Question 1

Where does the FDE cycle happen?

Answer 1

CPU

Question 2

Fetch =

Answer 2

Contents of PC copied into MAR

Address sent from MAR to main memory

Next instruction at that address is found & copied to MDR

Contents of PC increased by 1 to point to next instruction

Question 3

Decode =

Answer 3

Instruction held in MDR is copied to CIR

CU works out what the instruction is and sends signals to coordinate other registers

Question 4

Execute =

Answer 4

Instruction is executed sometimes using ALU to carry out calculation

Any results of processing stored in ACC

Once complete, cycle restarts

Question 5

Address Bus =

Answer 5

Carries memory addresses from the processor to other components

Question 6

Data Bus =

Answer 6

Carries data between processer and other components