Wired Interfaces: Enabling End-to-End Interfaces for ADAS, Infotainment and Autonomy

Rick Wietfeldt, MIPI Alliance board member and senior director at Qualcomm Incorporated

This is Part II of our talk with Rick Wietfeldt, MIPI Alliance board member and senior director at Qualcomm Incorporated, who will be presenting virtually at AutoSens Detroit on November 19. In Part I, Rick laid out details of the recently released MIPI A-PHY v1.0, a long-reach SerDes physical layer interface specification. In this installment, Rick talks about MIPI Alliance’s collaborative development initiatives and provides a brief overview of MIPI Automotive SerDes Solutions (MASS), a set of end-to-end interface solutions with A-PHY as the cornerstone. These solutions can ease implementation of advanced driver-assistance systems (ADAS), connected in-vehicle infotainment (IVI) and, ultimately, fully autonomous vehicles.

On November 19, you will be speaking on “A Collaborative Approach to Advancing In-Vehicle Connectivity.” Can you give us a sneak peak of your presentation?

I’ll be sharing how the MIPI Alliance is working across the organization, as well as with OEMs, in-vehicle connectivity suppliers and other organizations on specifications to advance in-car technology. We’re building on the MIPI specifications already used in many vehicles and making it easier for developers to integrate better safety, security and infotainment applications into future models. I’ll talk about the new MIPI A-PHY v1.0 long-reach serializer-deserializer (SerDes) physical layer and provide an overview of the MIPI Automotive SerDes Solutions (MASS), which is a portfolio of specifications that can be used to build end-to-end connectivity systems throughout a vehicle. These specifications will deliver higher quality, lower cost, more choice and easier implementation for consistent, standardized in-vehicle networks that connect peripherals like cameras and displays to electronic control units (ECUs), benefiting the entire automotive supply chain.

Tell us about how the MIPI Alliance has evolved to include specifications for automotive, the IoT and other areas.

The MIPI Alliance started out in the early 2000s focused on camera and display interfaces for mobile phones, and the standards developed helped to make smartphones a reality. With every generation of smartphones, there were better cameras and more powerful processors and displays, and this was largely made possible by the high-performance interfaces developed within MIPI. MIPI storage and chip-to-chip interfaces also enabled increasing phone performance.

Then the mobile revolution spread to other categories, including automotive and the IoT. For the auto industry, the MIPI interface specifications used in smartphones, tablets and laptops were ideal for linking the cameras, radar, high-resolution displays and lidar sensors coming into mainstream cars. Automakers have adopted MIPI CSI-2 and DSI-2, with C-PHY and D-PHY, for cameras and displays, plus MIPI I3C and other interfaces, to take advantage of economies of scale and a large ecosystem of developers and vendors. Now we’re able to extend those benefits to long-reach connections between components and processors anywhere in the car.

What are the latest developments in automotive for MIPI?

We’ve been very active in automotive this year. In September, we released MIPI A-PHY v1.0 to MIPI members. In conjunction with that release, we also introduced MASS, a series of end-to-end solutions that build on the benefits of A-PHY.

A-PHY is the first industry-standard, long-reach serializer-deserializer (SerDes) physical layer interface to support comprehensive functional safety and security. Its primary purpose is to extend the maximum distance of high-speed data transmissions between automotive cameras and displays and their related ECUs. It lets higher-layer protocols like CSI-2 and DSI-2 operate directly over physical links up to 15 meters anywhere in a vehicle. This will allow OEMs and suppliers to standardize and eventually eliminate the use of “bridges” between different PHYs, simplifying designs and cutting cost, complexity, weight and power consumption.

MASS establishes a complete “full-stack” solution to allow developers to set up A-PHY connections with functional safety and security between peripherals and ECUs. At the heart of MASS, closest to the A-PHY layer, is a set of standard protocol adaptation layers (PALs) that convert higher-layer protocols to A-PHY’s A-Packet format. PALs are being developed for MIPI CSI-2 and DSI-2, and for lower-speed protocols, including MIPI I3C, I2C, I2S, GPIO and Ethernet. Through liaisons with other entities, PALs are also being developed for third-party protocols, such as with VESA on a PAL for the DisplayPort / Embedded DisplayPort (DP/eDP) protocol.

At a higher layer of MASS, MIPI Camera Service Extensions (CSE) and Display Service Extensions (DSE) add functional safety and security capabilities as well as high-bandwidth digital content protection (HDCP) for display applications. These functional safety features are guided by requirements in the ISO 26262 standard to help designers build systems that meet ASIL (Automotive Safety Integrity Level) requirements at any level, from ASIL B to ASIL D.

System-level engineers can use A-PHY and MASS to improve both current and future safety and security features. For example, they will enable a reliable, high-performance connection between a rear-mounted backup camera and a high-definition dashboard display.

In this case, the camera monitors the area behind the vehicle as the driver backs up. The nominal connectivity would be the camera’s image stream transferred to a domain ECU anywhere in the car, using CSI-2 over A-PHY. After processing in the ECU, the camera stream is further transmitted over A-PHY to one or more displays using either DSI-2 or VESA DP/eDP. Security and functional safety features, as well as HDCP if necessary, are implemented “end to end” covering every connection in the link, from camera to display. In this configuration, functional safety and security are ensured from the camera all the way to the display.

We expect MASS to be applied to many other sensing applications, including lane-keeping and sign detection sensors, and 360-degree camera, lidar and radar systems. It can also be used to enable multiple high-definition displays for instrumentation, control and entertainment, including heads-up displays and virtual side mirrors.

Your presentation mentions “collaborative approach” in the title. Describe this approach and what it means for OEMs.

Automotive is a fast-growing area for interface development and a high priority for the MIPI Alliance. MIPI’s camera and display working groups have been coordinating closely with the technical steering and security groups to align requirements and protocols across these technologies. In addition, MIPI continues its outreach to OEMs and Tier 1 suppliers to solidify future needs and demonstrate how A-PHY and MASS meet upcoming challenges. Collaboration with third-party organizations, such as VESA for DisplayPort and others, is equally important. I’m happy to share another collaboration announcement with IEEE that will offer many benefits to the broader automotive ecosystem.

What’s next for MIPI in automotive?

A-PHY v1.1 is already in development. Using a form of “lane bonding” over a “quad conductor” connector, it will double the highest data rate to 32 Gbps and the uplink data rate to 200 Mbps. Updated versions of MIPI CSI-2 and DSI-2 are also in the works, coming in early 2021.

Many of the specifications being developed for the MASS protocol stack will be completed by the end of the year. These include the PALs for CSI-2, DSI-2, VESA DP/eDP, as well as those for I2C and GPIO. The camera and display service extension layers are also scheduled to be completed this year. That said, development work will continue into next year with the PALs for I2S, Ethernet and MIPI I3C, and security specifications for camera and display.

MIPI welcomes participation from OEMs, Tier 1 suppliers and the broader automotive ecosystem to help shape future specifications.

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