Juyun Weizhi

Jul 6, 2023

Zetta are the maintainer of the Eclipse Cyclone project and TTech has been working with them on safe automotive software development to rework the Cyclone open core to be certified to the ASIL-D level of safety. Adding TSN, developed by TTTech, adds real time Ethernet capability, and this is combined with the quality of service (QoS) priorities in DDS to ensure that time critical data is delivered with a known latency. Safety critical communications “We see Ethernet with TSN as the right technology and this fits nicely with DDS with the QoS. We test and integrate Cyclone DDS with TSN and bring the TSN planning tool to configure the whole TSN network,” said Heller. The in-vehicle integration uses the Zenoh protocol, also developed by the Eclipse project and written in the Rust language to handle data in embedded systems and queries in the cloud transparently. “The main way it provides the responsiveness is by being resource efficient as it has a low overhead across the medium and it is flexible about where you put the data, so with integration you can put data close to where it is required at the edge and make it easy for users to integrate,” said Heller. TTech is also using a different implementation of the Zenoh protocols called pico Zehoh and written in C for microcontrollers. This will be used to implement DDS for AutoSAR Classic for ASIL-D safety certification in software defined vehicles. “The pico version is optimised for a small footprint and is written in C for microcontrollers,” said Heller. “We want to make it easy to access DDS data through AutoSAR APIs so with the integrated Zehoh pico this seamlessly integrated with DDS in the microcontroller, they don’t need to configure much more and this will be available for ASIL-D.” ASIL-D certification Ensuring the software is safe is key, but the integrated APIs can help with the system-level certification. “There are a couple of aspects to the certification,” said Heller. “The first step is to define all the failure modes and these we cover in different ways, through the code quality, end to end protection with the integrated APIs so any lost data is known. Then to ensure the ASIL-D communications we are implementing TTTech shared memory into Cyclone to ensure the SAIL-D is not impacted by other applications,” he explained. DDS for V2X The V2X implementation will build on the in-vehicle software development for software defined vehicles but not with ASIL-D certification. “For us, what we see it is important that you have a unified underpinning for all the communication needs in the software defined vehicle, then building on that and integrating Zenoh. It is a natural transition to V2X so its looks like one solution,” he said.