Ethernet in Cars - The Next Big Thing for Ethernet

16 Jul 2014 • 2 minute read

Ethernet is coming to cars. Cars now have rear-view cameras and infotainment systems which require video to be transported at a high data rate. Ethernet is the best technology to carry this data.

Ethernet celebrated its 40th anniversary in 2013, and has evolved to support many speeds (10Mbps to 100Gbps) and environments. It is low cost, well understood, an open standard with many suppliers, and works well with TCP/IP and other protocol stacks.

In addition, power can be supplied over Ethernet cables, reducing the amount of wiring needed in a car. Ethernet enables a network of distributed programmable computers, allowing features to be implemented by software in general-purpose electronic control units.

Ethernet is implemented with a MAC layer and a PHY layer. For a given data rate, a common MAC connects to a PHY type suitable for the medium being used. Broadcom has developed a specialized automotive Ethernet PHY that can deliver 100Mbps over a single twisted pair cable and meet the harsh EMC automotive environment. Using a single twisted pair saves weight and cost and is an important factor for Ethernet being adopted in cars.

Cadence has an Ethernet MAC core with added functionality for automotive applications. In order to demonstrate interoperability with the Broadcom PHY, we put together a nice demonstration for CDNLive in Munich. This consisted of a NIC implemented on a Xilinx KC705 baseboard incorporating the Cadence PCIe and Ethernet IP cores, a daughtercard incorporating the Broadcom PHY, a Linux PC, an IP camera, and a media converter. We had to build the daughtercard ourselves using an FMC connector to connect to the Xilinx baseboard. The media converter made the connection between the regular Ethernet cable used by the IP camera and the single twisted pair from the daughtercard.

It was a challenge to get the demo working in time for CDNLive, but using this setup we were able to stream live video from the IP camera over the single twisted pair cabling to the Linux PC and view it on the Firefox web browser.

You can see a video of our demo in operation here: http://www.youtube.com/watch?v=LcXWcNeU-NY

And, below, you can see some photos of the components used.

Arthur Marris - July 2014