Automotive Ethernet

The automotive industry is trending toward Ethernet for in-vehicle networking (IVN) based on open IEEE standards. Driven by the OPEN AllianceSIG, these standards aim to develop a simpler, but more powerful, automotive electrical/electronic architecture. Demand is accelerating for deterministic, high-performance bandwidth features and low-cost cabling solutions, pointing to Ethernet-based networks as the solution. Ethernet for IVN provides the lowest cost cabling solution with low-weight, single-pair, unshielded twisted-pair cable.

Cadence offers a variety of IP to support automotive Ethernet applications (Figure 1). For example, you can design high-speed automotive Ethernet communication links between advanced driver assistance systems (ADAS), infotainment, cameras, and other electronic control units (ECUs) by leveraging the Cadence^® Ethernet controller.

Figure 1: Where Cadence IP fits in automotive Ethernet applications

Automotive Ethernet MAC Design IP

In order to build highly integrated Ethernet based SoCs, Cadence provides key design IP such as the Cadence Automotive Ethernet Media Access Controller (MAC) IP. The MAC IP supports three different operating speeds (10/100/1000M), the IEEE 1722 Audio-Video Bridging Transport Protocol (AVBTP) standard, and Time-Sensitive Networking (TSN).

AVBTP and TSN are the two key features to enable Ethernet for automotive applications. AVBTP describes how to guarantee bandwidth and enable data synchronization over Ethernet to ensure a high quality of service (QoS). However, to meet the safety and low-latency requirements of mission-critical control systems like braking, steering, etc., a new set of open standards—collectively referred to as TSN—is being developed. TSN enables robust, low-latency, and deterministic synchronized packet transmission and is a super-set of the AVBTP standard.

TSN is widely licensed for high-volume production, and supports:

IEEE 1722 AVBTP standard
- High data bandwidth, accurate timing (IEEE 1588), and highest QoS
- Highly accurate synchronization of multiple media streams by supporting the IEEE 802.1as and IEEE 802.1Qav standards
TSN to enable reliable and deterministic real-time data transfer for safety-critical applications such as camera-based driver-assist systems
- Address ISO 26262 requirements by supporting pre-emption, redundant path, etc.
Three different operating speeds (10/100/1000Mbps)
Bandwidth data transfer
Comprehensive software stack

Features

Standard	Description
802.1AS-Rev	Timing and synchronization for time-sensitive applications
802.1Qbu/802.3br	Frame pre-emption
801.1Qbv	Enhancements for scheduled traffic
802.1Qcc	Stream Reservations Protocol (SRP) enhancements and performance improvements
802.1CB	Frame replication and elimination for reliability
802.1Qch	Cyclic queuing and forwarding
802.1Qci	Per-stream filtering and policing

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Our Automotive Ethernet MAC IP can be combined with other IP or devices using standard interfaces. The accompanying physical coding sublayer (PCS) and connectivity IP let you interface Cadence MAC and third-party IP. It is compliant with the IEEE 802.3 specifications for 1G and10G Ethernet PCS layers. Our Ethernet PCS solutions ease integration of MAC IP with a broad range of PHYs.

Seamless interoperability with 100Mbps and 1Gbps Ethernet PHYs
Fully integrated in n-port-configurable Ethernet AVB switch

Richly Featured 10/100/1000 Ethernet MAC

AVB support
TSN hardware support for safety-critical control systems
Full-duplex flow control
IEEE 802.1Qbb Priority Flow Control
IEEE 802.1p Priority Queuing
IEEE 802.3az Energy-Efficient Ethernet
Statistics counters for RMON/MIB
Programmable-length jumbo frames
High-performance scatter/gather DMA
MII, RMII, GMII, RGMII, SGMII, and QSGMII interfaces
Integrated 1000BASE-X PCS with Clause 37 auto-negotiation IP/TCP/UDP checksum offload
LSO, RSC, and interrupt moderation
UNH tested

The full-featured 10/100/1000M automotive Ethernet MAC includes:

Embedded real-time clock and time-stamp unit
AVB including hardware support for priority queuing and traffic shaping
ARM^® AMBA^® 4 AHB or AXI-compliant DMA bus master on-chip interface
Open Alliance and IEEE 802.3 member

Sigrity SystemSI Automotive Ethernet Channel Simulation

Implement automotive Ethernet networks and analyze the ECU-to-ECU communication performance via the physical Ethernet channel with Cadence Sigrity^™ SystemSI^™ technology for automated chip-to-chip signal integrity analysis.

Simulate full physical channel to ensure Ethernet compliance:

Test different PHY, connector, and cable combinations
Support cable segmentation (different cable length)
Support with or without jacket, shielding
Enable simulation-based EMI verification and optimization from ECU to ECU
Analyze cable aging effects
Run power integrity analysis on PCB
Support automotive Ethernet compliance checks for 100Base-T1 PHY

Automotive Ethernet Compliance Checks for 100Base-T1 BroadR-Reach PHY

IBIS AMI models of PHY working on any cable topology
- TX and RX models
Physical channel simulated in Sigrity SystemSI technology
Supported compliance tests:
- Transmitter output droop
- Transmitter power spectral density
- Transmitter jitter (master/slave)
- Transmitter clock frequency (PAM3)
- Transmitter distortion
- Return loss measurement