New-Tech Europe | March 2017 | Digital Edition

Automotive Special Edition

Ethernet AVB - Ethernet Audio Visual Bridging provides the ability to route image data and other data around the vehicle as needed Should we elect to use a network the system architect must ensure the necessary bandwidth is available to transfer the image data between the camera and ADAS core with the required latency for its application. The data generated by the ADAS system may need to be shared with other systems within the car for instance adaptive cruise control, or parking assist. Therefore, the ADAS must be able to interface to other commonly used automotive interfaces like CAN or FlexRay. At the architectural level the use of an All Programmable Zynq® SoC based approach provides several advantages, if point to point wiring is used to interface to the cameras the camera receivers can be implemented in the programmable logic prior to the image processing chain. If an All programmable SoC were to be used the flexibility of the processor system side would allow for the easy inclusion of a CAN, Ethernet and other protocols like FlexRay when combined with logic in the programmable logic and an external PHY if necessary. The combination of dual core processors and programmable logic allows for a very low power per pixel, as the system is very tightly integrated. All Programmable SoC Architecture Where the SoC comes into its own is the utilization of the Programmable Logic (PL) to implement camera interface and image processing chain. While the Processing System (PS) of the SoC can provide the communication, control and additional algorithmic processing as required. The image processing

ADAS Head Up Application displaying navigation and situational awareness information

images and provide the information to the occupants. Many camera solutions use point to point LVDS wiring to transfer the data however, this brings with it additional cost and weight in the cabling required. There are however alternative approaches which are increasingly gaining ground, this pushes some functionality into the camera itself. If the image output by the camera is compressed and not the raw image, then network based architectures are possible. These networks could be based around commonly used automotive buses such as MOST (Media Oriented Systems Transport) - A high speed network which can be implemented in either optical or electrical physical layers IDB-1394 - High speed network implemented over an electrical physical layer, this is implemented in a daisy chained topology.

system challenges, which may not be obvious at first thought, vehicle manufacturers have stringent pollution standards to achieve and therefore the weight and power consumption of the overall solution is important. The cost of the solution is also critical due to the many tens / hundreds of thousands of vehicles being produced. While security and safety of the system is very critical and governed by a number of standards, using a SoC or FPGA can help us address a number of these. System Architecture The development of an embedded vision ADAS which monitors both external and internal cameras can be seen to be one of the more challenging ADAS implementations. This system needs to be able to interface to several cameras located around the vehicle, process the

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