Long-Reach SerDes PHY for Automotive Applications

The MIPI Alliance today announced that development has been completed on MIPI A-PHY v1.0, a long-reach serializer-deserializer (SerDes) physical layer interface for automotive applications. The specification is undergoing member review, with official adoption expected within the next 90 days.

A-PHY will provide a physical layer for data transfers spanning an entire vehicle. As the first standard of its kind, it will help the automotive industry accelerate the availability of advanced driver assistance systems (ADAS), autonomous driving systems (ADS), and other surround-sensor applications, including cameras and in-vehicle infotainment (IVI) displays.
MIPI A-PHY serves as the foundation of what will be an end-to-end system designed to simplify the integration of cameras, sensors and displays, while also incorporating functional safety and security. Higher-layer MIPI protocols, such as Camera Serial Interface (MIPI CSI-2) and Display Serial Interface (MIPI DSI-2), are already used to connect sensors and displays to domain ECUs and other onboard computers in many vehicles. They currently are transported over MIPI C-PHY or D-PHY shorter-reach physical layers and use »bridge« solutions to connect to proprietary long-reach PHYs. With the use of upcoming adaptation layers, these higher-layer protocols will run natively over A-PHY, eliminating the need for these proprietary bridges. Joel Huloux, chairman of MIPI Alliance, comments. »By offering a long-reach automotive wired connectivity solution, MIPI is building on its successful track record in the mobile industry, including its camera and display interface specifications, which are already prevalent in cars today.«
A-PHY is being developed as an asymmetric data link in a point-to-point topology, with high-speed unidirectional data, embedded bidirectional control data and optional power delivery, all over a single cable. Version 1.0 offers several core benefits:

• Simpler system integration and lower cost: native support for devices using MIPI CSI-2 and DSI-2, ultimately eliminating the need for bridge ICs
• Long reach: up to 15 meters
• High performance: 5 speed gears (2, 4, 8, 12 and 16 Gbps), with a roadmap to 48 Gbps and beyond
• High reliability: ultra-low 1E-18 packet error rate for unprecedented performance over the lifetime of a vehicle
• High resilience: ultra-high immunity to EMC effects by virtue of a unique PHY-layer retransmission system

MIPI A-PHY will allow designers to optimize systems for the performance, cost and complexity required by their use cases, providing scalability and flexibility to meet a broad range of speed and design needs. For integration with existing network backbones, A-PHY complements Ethernet, CAN, FlexRay and other interfaces.
In addition, MIPI Alliance will work with other organizations to leverage native protocols through a generic data link layer included with A-PHY. As one such effort, MIPI has extended its liaison with VESA and is actively developing an A-PHY adaptation layer for use with its DisplayPort and Embedded DisplayPort standards.
To help ensure the interoperability of devices using A-PHY, a compliance test suite for testing developers’ implementations of the specification is already under development, and additional test resources and programs are being evaluated.