Page 22 - EE Times Europe Magazine – June 2024

22 EE|Times EUROPE

New Developments in MIPI’s High-Speed Automotive Sensor Connectivity Framework

MIPI image sensor security

benefit vehicle imaging systems include: error rate of <10 over the lifetime of a in the recently introduced
–19
• Always-on sentinel conduit: Enables vehicle CSE v2.0 (May 2024). Services are imple-
always-on vision systems in which • High resiliency, with ultra-high immunity mented using the Service Extension Packet
combinations of ultra-low-power to automotive EMI effects (SEP) or Frame-Based Service Extension Data
image sensors and video digital-signal • Bounded low latency (maximum 6 µs) (FSED) protocol, providing flexibility, particu-
processors continuously monitor their • Support for multiple cable types (coaxial, larly when implementing CSE services within
surrounding environments and wake shielded differential pair and star quad) legacy solutions.
their higher-power host ECU only when • Long reach (up to 15 meters in length CSE FuSa services include message
significant events happen with four inline connectors) counters, cyclic redundancy checks, built-in
• Multi-pixel compression: Provides • Multiple power-over-cable options, self-tests with error-injection capabilities
optimized pixel compression for the latest including support for 48-V operation with and a baseline timeout-monitoring service to
generation of ultra-high-resolution image the Power over A-PHY v1.0 specification detect loss of communication.
sensors with multi-pixel color filter arrays The A-PHY physical layer can transport CSE security services enable authenti-
• RAW-28 color-depth pixel encoding: multiple higher-layer protocols through its cation, integrity protection and (optional)
Supports both higher image quality and generic data-link layer and a set of protocol encryption of image sensor data. They provide
signal-to-noise ratio in high- adaptation layers (PALs) that map these a high degree of flexibility to balance the
dynamic-range automotive image sensors protocols to A-PHY’s A-Packet format. required security levels against processing
• Smart region of interest: Enables In addition to PALs that support native efficiency, thermal regulation and power
more efficient analysis of images using coupling to CSI-2 and DSI-2, PALs have consumption. Other features include:
AI-based vision inferencing algorithms been developed for several lower-bandwidth • Choice of cipher suites: Options include
The use of CSI-2 within automotive control interfaces, including I C, GPIO, an “efficiency” cipher suite providing
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applications is augmented with MIPI Camera Ethernet, SPI and the emerging I3C AES-CMAC data integrity only (no
Service Extensions (CSE), which provides interface. encryption) targeted toward sensors with
functional safety and security, and the MIPI To support implementers, a reference com- limited hardware resources, as well as a
Camera Command Set (CCS), which provides pliance test suite is currently being finalized, “performance” cipher suite that provides
command and control. and a compliance program is under develop- AES-GMAC data integrity and optional
ment so that automotive original equipment AES-CTR encryption aimed at sensors
HIGHER UPLINK AND DOWNLINK SPEEDS manufacturers and system designers will be with dedicated hardware support.
IN THE NEXT A-PHY SERDES UPDATE able to validate that MIPI A-PHY devices have • Choice of tag modes: These multiple tag
The A-PHY physical layer interface addresses been tested and deemed compliant with the mode options allow the implementer to
the need for a standardized long-reach, specification. A-PHY has also been adopted as choose how often the tag is computed and
highly reliable, asymmetric SerDes solution to IEEE 2977-2021. transmitted.
simplify the integration of image sensors and • Granular security controls: These
displays into automotive E/E architectures. It END-TO-END, APPLICATION LAYER, controls provide highly granular “source
is designed to meet the specific needs of the FUNCTIONAL SAFETY AND SECURITY selective” control over the different seg-
automotive industry, offering resiliency and FOR AUTOMOTIVE SYSTEMS ments of the CSI-2 image frame to enable
reliability and eliminating the need for pro- MASS includes functional safety and security a “sliding scale” of security levels.
prietary PHYs and bridges. A-PHY simplifies features to fulfill ADAS safety goals up to MIPI camera security is effective in both
in-vehicle communication networks, reducing ASIL-D (per ISO 26262:2018) and enable end- its security extent and implementation flex-
costs, weight and development time. Key to-end protection as recommended for “high” ibility. When both security and FuSa service
features of A-PHY are: diagnostic coverage of the data communica- extensions are enabled, security is layered
• Downlink data rates of up to 32 Gbps in tion bus. on top of functional safety; from a source (or
A-PHY v1.1.1, with up to 64 Gbps sup- CSE, which can be applied anywhere the transmitter) perspective, security is applied
ported in A-PHY v2.0 (expected Q2 2024) CSI-2 imaging protocol is used and is agnostic to the image data first, followed by func-
• Uplink data rates of up to 200 Mbps in of the underlying transport layer, enables tional safety. ■
A-PHY v1.1.1, with up to 1.6 Gbps sup- functional safety and security for imaging
ported in A-PHY v2.0 applications. FuSa functions were included in Ariel Lasry is vice chair of the MIPI A-PHY
• High reliability, with an ultra-low packet CSE v1.0, and security functions were added working group at the MIPI Alliance.

JUNE 2024 | www.eetimes.eu