Ozone-Sim

SEGGER Ozone-Sim is a high-performance instruction set simulator for Arm and RISC-V that runs embedded applications directly on a PC, with no target hardware and no J-Link required. It ships bundled with the standard Ozone package but needs a separate license key, and it lets development, debugging, and automated testing start long before production hardware is available.

Key features

How Ozone-Sim works with Ozone

1. Build the application: compile and prepare the executable as usual.
2. Configure the simulation: launch Ozone and select Ozone-Sim as the target/host interface.
3. Load the executable: import the firmware into the simulation environment.
4. Debug and analyze code: run, inspect, profile, and validate firmware behavior.
5. Review execution insights: examine execution metrics and backtraces.

Once Ozone-Sim is running, the debugging and analysis features are the same ones Ozone already provides on real hardware: source-level and assembly debugging, profiling, backtrace support, live instruction counters, and code coverage. Switching between a real J-Link/J-Trace connection and the simulated target is straightforward, and Ozone-Sim can display real-time code coverage and profiling just as when debugging on real hardware with J-Trace, then export that information to help automatically identify functional or performance deviations.

Hardware-free testing and CI/CD

Ozone-Sim’s standalone command-line mode is built for headless and automated testing, the mode most teams reach for once they want simulation inside a build pipeline rather than an interactive debug session.

Built-in semihosting is what makes this practical for regression testing: the simulated program can read configuration or test vectors, then write logs, results, and other output directly to files, with parameters passed in over the command line. That turns Ozone-Sim into a repeatable, scriptable test target that a CI/CD pipeline can call the same way it calls any other build step, no lab hardware, no probe contention between engineers, no waiting for a free test rig.

For teams that also validate on physical targets, J-Trace PRO hardware-in-the-loop trace remains the reference point Ozone-Sim results can be checked against.

Using Ozone-Sim in other IDEs (GDB server)

Ozone-Sim is not limited to the Ozone application. It includes an integrated GDB server interface, so third-party debuggers and IDEs, including Visual Studio Code, SEGGER Embedded Studio, or any generic GDB client, can connect to the simulator over the standard GDB protocol. Teams that already have a GDB-based debug workflow can point it at Ozone-Sim and get hardware-free simulation without changing their day-to-day IDE.

How Ozone-Sim compares to QEMU and Renode

Teams evaluating hardware-free simulation often weigh Ozone-Sim against the two established open-source options, QEMU and Renode. They solve overlapping but different problems, and the honest trade-off is fidelity versus integration and support.

Ozone-Sim does not set out to reproduce peripheral electrical behavior or cycle-exact timing, which is where QEMU’s full-system emulation and Renode’s peripheral models have the edge. Its advantage is speed and running inside the same Ozone debugger and workflow that engineers already use on physical targets, so there is no second tool to learn and no discontinuity between simulated and real-hardware debugging. For tests that depend on real peripheral timing or electrical behavior, pair simulation with J-Trace PRO hardware-in-the-loop trace.

Supported architectures

*Armv8.1-M support excludes half-precision floating point and includes a subset of the M-Profile Vector Extension (Helium). SEGGER notes that support for additional architectures and instruction-set extensions may be added in future releases.

System requirements

Licensing and evaluation

Ozone-Sim is bundled with and installed as part of the standard Ozone package, but it requires a separate license key. Full hardware-free simulation inside Ozone needs active licenses for both Ozone and Ozone-Sim. SEGGER offers a 30-day evaluation of the full feature set, with the trial period beginning on first use, whether inside Ozone or as a standalone simulator, and no trial-license request needed to get started.

Ozone-Sim in India with GSAS

GSAS is SEGGER’s authorized engineering partner in India, and Ozone-Sim is where our field application engineers add the most value before a single license changes hands. Getting real use out of a hardware-free simulator, wiring it into an existing CI/CD test rig, choosing standalone CLI versus the GDB server for a given IDE, mapping semihosting output to your existing log pipeline, is application engineering, not invoicing. Our FAEs across Bengaluru, Chennai, Hyderabad, Pune, Mumbai, and Delhi NCR work directly with teams evaluating Ozone-Sim for early software bring-up, including RISC-V teams building on Shakti and Vega cores who want to start firmware validation before silicon or boards arrive. Talk to GSAS about evaluating Ozone-Sim, or request a quote once you’re ready to license alongside Ozone.