SLR01 – Structure and function of the processor (AS & A’Level)

Question 1

What is the central processing unit (CPU) and its components?

Answer 1

Portion of a computer that retrieves and executes instructions

1. control unit
2. buses
3. ALU - arithmetic logic unit

Question 2

What does the control unit do?

Answer 2

Control unit: part of processor that coordinates activity of all other components. Control signals are sent along the control bus between control unit and other components of the computer

Question 3

What is the system bus?

Answer 3

System bus: consists of 3 separate buses carrying control signals, addresses and data

Question 4

What is the bus?

Answer 4

Bus: consists of a series of connectors that transfers signals between internal components

Question 5

What do the control signals include?

Answer 5

Memory Read: causes addressed location in RAM to be placed on the bus data

Memory write: causes data on the data bus to be written into the addressed location RAM

Bus request : Indicates device is requesting use of the data bus

Bus grant: indicated that CPU has granted access to data bus

Clock: used to synchronise operations

Interrupt request: a signal sent to a computer’s processor to momentarily stop (interrupt) its operations