SAE releases deterministic Ethernet
November 10, 2011 by John Day
SAE AS6802 – Time-Triggered Ethernet – is the new industry standard that establishes Ethernet as a deterministic networking technology. It’s available for download at http://standards.sae.org/.
Although the source of the new standard, SAE International’s AS-2 Embedded Computing Systems Committee, is part of SAE International’s Avionic Systems Group, automakers and suppliers are known to be interested.
Time-triggered Ethernet provides an alternative to FlexRay for automotive applications that require deterministic performance. FlexRay has been gaining momentum. NXP Semiconductors said it took three years from the launch of its FlexRay Physical Layer compliant transceiver to reach the one million unit shipping milestone. Achieving two million unit shipments took less than one year.
But Ethernet has been increasingly visible. In September Texas Instruments announced the Hercules TMS570, its highest performance product line for transportation applications. It includes specific connectivity provisions for both FlexRay and Ethernet, as well as the ubiquitous CAN.
In August, Renesas Electronics announced the R-Car E1, a system-on-chip (SoC) for cost-sensitive car navigation and multimedia systems, including high-end car radios. The device supports communications interfaces including MOST, Ethernet, and CAN.
Ethernet’s high bandwidth offers advantages for camera systems among other applications. Freescale Semiconductor last summer introduced a 32-bit Qorivva microcontroller (MPC5604E) developed in collaboration with BMW. The MCU is designed to make surround-camera parking assist systems affordable for a broader range of vehicles.
“The MPC5604E will help establish Ethernet as a dependable long-term solution for broadcast of video and other forms of data around the automobile,” said BMW senior systems architect, Networks, Thomas Koenigseder. Using Ethernet two-wire networks, automakers can reduce material expenses and lower weight while improving performance.
Freescale noted that for video transmission, a vehicle typically needs several low-voltage differential signaling (LVDS) cables at a cost of roughly $10 each. In contrast, the new MCU transmits high-resolution compressed video data over Fast Ethernet for a 360°view around the vehicle to help make parking simpler and safer. By compressing and transmitting the video signals via Ethernet, the MPC5604E eliminates the need for cables and saves on the bill of materials.