Control unit

Register

Address 1

Click the Start button to watch the cycle. You can pause, resume and re-run the simulation.

Address 2

Data

CPU

Start

Bus

Address

Decoder

Pause

ALU

Proceed

ME M O R Y

Program counter

Instruction

Registers

The fetch - decode - execute cycle

Carry out the instruction

Well done! They are all correct.

Increment program counter

Fetch the instruction pointed at by the program counter

Check

Decode the instruction

Complete the following flow diagram by dragging the statements from the list at the right into the spaces provided. When you have finished, click the Check button.