Interactive CPU Simulator – OCR GCSE Computer Science

Interactive CPU Simulator – OCR GCSE Computer Science

Bring the fetch–decode–execute cycle to life with this visual, teacher-led CPU simulator, designed to support OCR GCSE Computer Science J277, section 1.1.1.

The CPU and RAM appear on a motherboard, connected by a visible bus. Step through a simple program and watch addresses, instructions and data move between components.

Full-screen Board mode for classroom demonstrations: display the simulator on an interactive whiteboard or projector. The layout automatically scales to keep the controls, explanations, CPU, bus and RAM visible together.

Features include:

• PC, MAR, MDR and accumulator, with full names and purpose labels.
• Control Unit, ALU, RAM and an identified cache.
• Assembly-style instructions in RAM, explained in plain English during decode.
• Colour-coded transfers and clear explanations at each stage.
• An animated PC increment and ALU calculation.
• Next, Back, Restart and Replay controls.
• Full-screen Board mode that scales the demonstration to fit your display.

Ideal for whole-class explanations, questioning and revision. Teachers control the pace, with clear transitions between fetch, decode and execute.

Easy to use: download the HTML file and open it in a modern browser. No installation, internet connection or account is needed for the simulator.

This is a simplified teaching model. The assembly-style instructions and register transfers illustrate how processing works; they are not an additional instruction set students need to memorise.