Your application. Its own processor.

Fusion is RIoT Secure’s hardware sandbox architecture. Customer application firmware runs on its own microcontroller, with CPU, memory and peripherals dedicated to the job the device needs to do. The communication and security engine uses a separate processor’s resources.

Security handshakes, network processing and lifecycle operations run in that separate execution domain. The application team retains its own scheduling, toolchain and programming model, with a defined interface to the lifecycle infrastructure. This puts application execution at the centre of the hardware design.

For mission-critical applications, predictable execution is part of the device’s job. Control loops, sensor sampling and actuator responses can have specific timing requirements. Fusion keeps application processing on a dedicated MCU, while communication and security work executes on a separate processor.

This gives engineers a defined hardware domain in which to design, measure and validate application timing and reliability. Over a long service life, application firmware and the communication stack can follow their own development and maintenance cycles, with change managed at the interface between them.

The Arduino UNO R4 WiFi combines a Renesas RA4M1 Arm Cortex-M4 application processor with an ESP32-S3 communication processor. Fusion can use that existing two-processor arrangement without an external reference shield. The ESP32-S3 runs communication and lifecycle functions while the RA4M1 remains dedicated to application logic and peripheral control.

This provides another path from evaluation to implementation using the same architecture. Fusion is defined by the separation of application and communication responsibilities, rather than a particular board or form factor.

Fusion provides the hardware separation within the wider RIoT Secure platform. The communication and security MCU connects application devices to provisioning, protected data exchange, software delivery and fleet operations, while customer firmware retains its own execution environment.

Brawl adds a WebAssembly execution option for portable application logic. Its software sandbox and Fusion’s physical separation address different execution requirements; teams can select or combine them around the application and hardware design while using the surrounding lifecycle infrastructure.