Components

Front 1

Control unit

Back 1

Coordinates and controls computer by generating control signals and performing the f/e cycle

Front 2

Arithmetic and logic units

Back 2

Performs arithmetic and logical operations on data

Front 3

Registers

Back 3

High speed memory cells (e.g. Program counter)

Front 4

System buses

Back 4

A bus is made of parallel wires connecting components of a computer

Front 5

The 3 buses

Back 5

- Control bus

- Address bus

- Data bus

Front 6

Control bus

Back 6

Bi-directional signals that control the operation of the system components

Front 7

Address bus

Back 7

Uni-directional. Carries the address of the location of an instruction or data, to be written to read to memory or io controller

Front 8

Data bus

Back 8

Bi-directional. Carries program instructions or data

Front 9

PC

Back 9

Program counter. Points to next instruction to be fetched

Front 10

MAR

Back 10

Memory address register. Holds address of memory location being accessed by the processor

Front 11

MBR

Back 11

Memory buffer register. Holds the data item being transferred to or from memory location currently being accessed by the processor

Front 12

CIR

Back 12

Current instruction register. Holds the current instructions to be executed

Front 13

ACC

Back 13

Accumulator. Holds the result of the current calculation