Rules of the game are clear from the outset
Along with the 3D graphics, a virtual control device will also need broad-based access to individual physical input and output units. However, this could mean that several applications could conflict with each other. This is why the ECU architect needs to distribute the resources across the virtualised devices. It helps if the chosen SoC can provide several units or independent data paths for the same task. Each R-Car includes enough standard interfaces like UARTs or USB, so that static resource allocation is the most convenient method. Conversely, other accelerators – such as video decoders should be used in a time multiplex to offer the maximum level of flexibility. Video outputs provide independent display layers that can be allocated to each virtualised device and then combined centrally into a single image (Fig. 4).
All this needs to be agreed between the subsystem suppliers from the outset. In addition, it is important that the provider of the hardware driver also supports this concept. For example, although different video display layers can isolate their data paths from each other, there can only be one centralised driver that sets up the video output. In the case of the R-Car, Renesas delivers the device drivers required to support this distribution.
As different subsystems are now combined in one ECU, the integration tests are also transferred to the ECU. Tasks that carmakers carry out when vehicle development is finished are now managed by the ECU architect. It will be interesting to see how the industry deals with this challenge going forward – and without making development cycles even longer. In future, SoC makers will need to be more involved in this process from the outset. Simply adopting products destined for consumers will not work – they will not comply with the automotive industry’s high development standards in terms of security and safety.
The reward: future-proof solutions
Companies that master these challenges will benefit from a completely new level of freedom. With integrated cockpits, HMI designers can move information from the infotainment screen to the central driver display if the situation requires it. That enables the computing-intensive navigation function to be generated on common hardware and temporarily display a route map in the driver’s line of vision. This approach reduces hardware – because separate systems would need double the amount – and eliminates the need for wiring between the two. Processing power reserves only need to be allocated once and will be distributed more evenly depending on the application. As a result, virtual controller devices running on central, powerful servers provide the benefit of significant potential cost savings.
With its R-Car, Renesas offers customers a concept that is highly scalable within one product generation, while also remaining compatible with the next generation. That enables customers to recoup their – initially high – investment in virtualised control devices very quickly. The reward for this investment in central server ECUs is a cost-effective performance reserve to handle future extensions to functionality that are currently still unplanned. These could then be sent to the customer as an over-the-air update.
About the author:
Peter Fiedler is Senior Manager, Automotive Solution Business Unit at Renesas Electronics Europe.