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        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.

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