1
Q
Fetch
A
The control unit fetches the next instruction / data item, requesting the address of the data / instruction along the data bus whilst sending clock signals along the control bus. The instruction/data bus and is stored in the appropriate register.
2
Q
Decode
A
The control unit then receives the instructions and decodes it by looking it up in its instruction set.
3
Q
Execute
A
The ALU will then perform the appropriate calculation, after which the Control Unit will use the address bus to request a memory location to store the output. The control unit will then send the data back to memory along the data bus.
