The drive towards autonomous and connected mobility is dramatically re-defining vehicle architecture as we know today. The car will become a ‘data-centre on wheels’, connecting cloud to device, characterized by software and no longer the mechanics. Ethernet provides the physical layer to enable the in-vehicle networking migration towards centralized high-performance computing with zonal ECUs.
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However, the trend to this homogeneous ‘all Ethernet’ vehicle network provides a solution to another, more fundamental challenge faced by the automotive industry. That is the wiring harness. Today high-end vehicles require up to 5km of wiring looms, making it the 3rd most costly and heaviest item in a vehicle, after the engine and chassis. Not satisfied with Ethernet’s ability to transport multi-application data over a cable, the industry went one step further and defined new IEEE Ethernet PHY specifications to reduce the number of twisted pair wires within those cables, to just a one! The birth of ‘Single Pair Ethernet’ or SPE for short.
Such benefits are not limited just to the automotive industry, after all the move towards centralised computing is echoed across numerous cloud-to-edge markets such as, industrial automation networks and IoT.
Single data transmission technology to allow access all devices
Just ask yourself the question, ‘Would your network connectivity benefit from reduced weight, cost and installation complexity?’ Easy answer, right?
Ethernet is ‘dab hand’ at offering interchangeable physical layer transceivers; coax, 2-Twisted Pair, 4-Twisted Pair and fibre to name a few. Over the coming years Single-Pair, for sure, will be commonplace in a multitude of different applications and markets.
SPE is not just for Automotive networking!
So what are the major PHY difference for Single Pair Ethernet?
There is seemingly a compromise using Single Pair Ethernet, reduced cable reach, as shown in the comparisons charts. Although, this is more to do with the needs of the automotive industry itself rather than the technology. 15m is the maximum length of cable you’ll even need in a car, so why specify more when you still must meet stringent enviromental challenges? Suppliers, like Microchip Technology have demonstrated much further reach with SPE devices, similar to the common 100m Ethernet cable reach we are accustomed to.
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1000BASE-T vs 1000BASE-T1 PHY Transceivers |
100BASE-TX vs 100BASE-T1 PHY Transceivers |
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10Mbps IEEE 802.3cg 10BASE-T1S is a slightly differ type of Single Pair Ethernet. Not only does it benefit from using a single twisted pair wire, it offers bus topology connectivity, in addition to the conventional switched point to point. Connecting devices on a common bus offers further system cost reductions by reducing the number PHYs and cabling needed in the network (below). Up to at least 8 devices (PHYs) can be supported over the shared 10Mbps bus of up to, at least 25m in length.
10BASE-T1S is also deterministic by inherently avoiding collisions from devices simultaneously trying to transmit on the bus, through a method known as PLCA (Physical Layer Collision Avoidance).
Microchip Complete Single Pair Ethernet Networking Solutions
Microchip is a proven, valued leading supplier across multiple end markets, including Industrial, Data Centre and Computing, Automotive, Communication, Consumer and Aerospace.
Delivering the first industrial and automotive grade ethernet devices to the market we continue to innovate and extend our diverse product portfolio, enhanced with a ‘No End of Life’ policy.
Our Single Pair Ethernet solutions provide designers the differentiation, performance and support to succeed.
• Flexible and scalable system solutions
• Lowest power PHY, wake/sleep modes
• Smallest packages
• Extended cable reach
• Security support
• Functional Safety Ready
• Ambient temperatures up to 125◦C
• Comprehensive software & Tool support
• LANCheck® design services