Simulation Overview in VxWorks

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Developing real-time embedded projects often comes with hardware challenges—shared boards, delayed availability, or early prototyping needs. Fortunately, VxWorks provides a range of simulation tools to overcome these obstacles. By simulating target boards and processors in software, developers can start coding, testing, and debugging before hardware is ready.

Learning Objectives

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After this section you will be able to:

• Identify and understand the different simulator options available in VxWorks.

Why Use Simulators?

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Simulators play a vital role in VxWorks development workflows. They allow you to:

• Start development even if the target hardware is unavailable.
• Enable multiple developers to work without needing a dedicated board.
• Prototype and test applications in a controlled environment.
• Accelerate development by providing hardware-independent testing.

Choosing the right simulator depends on the phase of your project and your specific needs.

VxWorks Simulator (VxSim)

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VxSim is an OS-level simulator designed for early development stages.

• It does not simulate hardware or processors, so it lacks deterministic behavior.
• Ideal for early application development, before processor-specific code is introduced.
• Lightweight, easy to set up in Workbench, and enables fast project startup.

⚠️ Note: VxSim should be phased out as soon as processor-specific development begins or when code qualification is required.

The QEMU Simulator

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QEMU is an open-source processor simulator widely used in embedded development.

• Supports a range of target boards by simulating the Board Support Package (BSP).
• Can replicate hardware targets based on the host system architecture.
• Allows developers to write and test processor-specific code before the hardware is ready.

This makes QEMU a powerful tool for prototyping and testing in the early-to-mid phases of VxWorks projects.

Simics Simulator

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Simics© is a true hardware simulator that provides the most accurate and comprehensive simulation environment for VxWorks.

• Simulates CPUs, entire boards, or even systems with multiple boards.
• Integrates with Workbench exactly as a real hardware target would.
• Enables instruction-accurate development before physical hardware exists.
• Offers advanced analysis tools, including:
  • Execution tracing
  • Reverse execution
  • Fault injection
  • Simulation checkpoints

Simics is particularly valuable for complex projects where accuracy, system-level debugging, and hardware-dependent testing are critical.

Key Takeaways

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• VxSim – Lightweight OS simulator, great for early development.
• QEMU – Processor simulator that supports board-level prototyping before hardware.
• Simics – Full hardware simulation with instruction accuracy and advanced debugging.

By leveraging these simulators, VxWorks developers can accelerate their projects, reduce dependency on physical boards, and ensure code is well-tested long before hardware is deployed.