The automotive industry revolutionized the definition of a vehicle in terms of safety, comfort, enhanced autonomy, and internet connectivity. With this trend, the automotive industry rapidly adopted automotive Ethernet such as 10Base-T1, 100Base-T1, and in some cases, 1000Base-T1.
Faster Speed (than CAN-FD), Scalability, embedded security protocols (like MacSec), cost and energy efficiency, and simple yet redundant network made Ethernet an obvious choice over CAN(FD) and FlexRay.
Ethernet 10Base-T1
10BASE-T1S is defined under IEEE with 802.3cg. The S in 10BASE-T1S stands for a short distance. 10BASE-T1S uses a multidrop topology, where each node connects to a single cable. Multidrop topology eliminates the need for switches and, as a result, fewer cables/less cost. The primary goal of 10BASE-T1S is a deterministic transmission on a collision-free multidrop network. 10BASE-T1S cables use a pair of twisted wires. As per IEEE, at least eight nodes can connect to each, but more connections are feasible.
The Physical Layer Collision Avoidance [PLCA] protocol ensures that it uses the entire 10 Mbps bandwidth. In 10BaseTs, Reconciliation Sublayer provides optional Physical Layer Collision Avoidance (PLCA) capabilities among participating stations. Using PLCA-enabled Physical Layers in CSMA/CD half-duplex shared-medium networks can provide enhanced bandwidth and improved access latency under heavily loaded traffic conditions. The working principle of PLCA is that transmit opportunities on a mixing segment are granted in sequence based on a node ID unique to the local collision domain (set by the management entity). 10BASE-T1S also supports an arbitration scheme that guarantees consistent node access to the media within a predefined time.
The 10BASE-T1S PHY is intended to cover the low-speed/low-cost applications in the industrial and automotive environment. A large number of pins (16) required by the MII interface is one of the significant cost factors that must be addressed to fulfill this objective. The 10BASE-T1S "Transceiver" solution is suited for embedded systems where the digital portion of the PHY is fully integrated, e.g., into an MCU or an Ethernet switch core, leaving only the analog portion (the transceiver) into a separate IC.
Ethernet 100Base-T1/1000Base-T1
100Base-T1 and 1000Base-T1 can be used for audio/video information. With Higher bandwidth capacity, 100Base-T1/ 1000Base-T1 paired with AVB (Audio video bridging) can be used for car infotainment systems. 100Base-T1/1000Base-T1 paired with time-sensitive networking [TSN] protocol can be used to fulfill the automotive industry's mission-critical, time-sensitive, and deterministic latency needs.
PTP Over MacSec
With today's automotive network, all the Electronic Control Units connected require timing accuracy and network synchronization, Precision Time Protocol (PTP), defined in IEEE 1588, provides synchronized clocks throughout a network. While maintaining the timing accuracy for mission-critical applications, protecting the vehicle network from vulnerable threats is mandatory, and PTP over MacSec provides the consolidated solution.
With the availability of the Cadence Verification IP for 10/100/1000BaseT1 and TSN, adopters can start working with these specifications immediately, ensuring compliance with the standard and achieving the fastest path to IP and SoC verification closure. The 10/100/1000GBaseT1 and TSN provide a full-stack solution, including support to the PHY, MAC, and TSN layers with a comprehensive coverage model and protocol checkers. Ethernet BaseT1 and TSN VIP covers all features required for complete coverage verification closure. More details are available in the Ethernet Verification IP portfolio.
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