Hirofumi Shigehisa
Hirofumi Shigehisa
Sr Mgr, Software Engineering
Published: July 20, 2022


Renesas provides the central gateway R-Car S4 SoC which is the core of the E/E architecture and the software running on it. The central gateway connects the vehicle to the outside world and controls data communication within the vehicle. By connecting the vehicle to the cloud, for example, useful services such as stolen vehicle tracking and remote troubleshooting have been initiated.

This blog focuses on the software that runs on the R-Car S4.


The amount of data handled to improve convenience and ensure the safety of vehicles is increasing every year. To manage the increasing data communication efficiently, E/E architectures are shifting from traditional distributed control to a domain or zone control. As a result, the central gateway was born. The central gateway controls the connection between the cloud servers and the vehicle, as well as between the different network domains in the vehicle.


The de facto standard for communication protocols used in in-vehicle networks has been CAN, which is standardized in ISO standards. However, recently Ethernet, which enables high-speed communication for large-volume data communication, has become popular. Therefore, central gateways are required to handle these protocols.

Software for the central gateway R-Car S4

Here is the introduction of the software that runs on R-Car S4. For the detailed information on R-Car S4 please click here.

  • Renesas provides the R-Car S4 SDK (Software Development Kit) for R-Car S4. This SDK packages the essential software to realize gateway functions, including the Ethernet driver (Autosar MCAL/Linux BSP), Ethernet Switch Control Library, and CAN-Ethernet Conversion Library. Customers can easily start developing gateway applications by using the SDK.

    Here are some typical gateway softwares.

    Ethernet Switch Control Library

    The Ethernet Switch Control Library provides the API for easy access to the rich functionality of Ethernet Switch HW IP. This Library performs routing processing using data in the payload via Ethernet Switch HW IP on R-Car S4, such as protocol type (UDP, etc.) and EtherType (Ping, ARP, etc.), which has traditionally been performed by the customer's own software on the CPU. The processing by the Ethernet Switch HW IP shortens the execution time compared to the software processing on the CPU, and low latency data transmission is realized. This low latency data transmission realizes more real-time processing from anomaly detection to response and increases safety.

    CAN-Ethernet Conversion Library

    The CAN-Ethernet Conversion Library performs mutual conversion between CAN frame data and Ethernet frame data. If this conversion process is performed using the PDU router of Autosar BSW prepared by the customer, the CAN frame data and Ethernet frame data cannot be converted directly, so it takes time to complete the conversion process. However, the Library allows direct data conversion, thereby shortening the time required to complete the conversion process. Renesas believe this will contribute to low latency data transmission.

    R-Car S4


  • Renesas provides not only an evaluation board but also a virtual development environment to run the SDK. This means that gateway application development can be started even without an evaluation board. Renesas are also considering incorporating debugging functions into the virtual development environment that are not available on the actual device to help customers solve problems. For example, if data is not reaching the expected destination, it may take time to resolve the issue. This is because it is necessary to investigate complex routing configurations to determine the cause. In this case, Renesas believes that providing debugging information to the customer that cannot be obtained from the actual device will speed up the identification of the cause.
  • Customers can download the SDK from the WEB. Sample code is also provided so that customers can check the performance and functions of R-Car S4 immediately after downloading. Renesas also plans to upload videos showing the method to start up the evaluation board and use the SDK soon.


This blog mainly introduced the software that runs on R-Car S4. Renesas will continue to contribute to the realization of a convenient and comfortable society by providing better software and development environment.

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