Revving up Automotive Embedded Storage with UFS

As demand for UFS 4.0 is beginning to set in, silicon-proven automotive solutions in the market today support UFS 3.0 that can go up to 2.9GBps with 2 lanes. Given that the interface is bidirectional, we are talking about +6x the speeds possible over eMMC transfers.  This data-rate exceeds that of 5G transfers (2.5GBps) allowing for smaller internal memory inside the host processor when data is being transferred between the flash device and external systems beyond the host processor.

Not just the interface speed, but also the flash write speeds are evolving. JEDEC enhanced the write performance by introducing the write booster feature in UFS 3.1 that adds a small pseudo SLC cache in the flash devices for easy and repeated accesses.

In terms of noise management too, UFS trumps eMMC. Unlike eMMC which is single ended, the UFS interface is differential making the system more resilient to transmission errors and noise implying lesser probability of incorrect data interpretation and/or need for retransmission. The differential signaling also provides better EMI performance making it easier to pass Automotive EMC Standard, CISPR 25, at system level.

Automotive storage is at a far higher risk of damage than consumer-grade variants. Vehicle behavioral stability and reliability is of great concern for consumers and manufacturers. Automotive storage is at a far higher risk of damage than consumer-grade variants. UFS lowers overall risk of wear and tear of the storage device by allowing the storage device to notify the host about large temperature variations. When the storage device indicates alarming temperatures, the host can throttle down or take actions to cool down the device temperature.

Low power operation is a mandatory requirement for electronics to reduce carbon footprint and extend battery lifecycle. UFS achieves this through differential signaling and ability to switch to deep sleep mode. 

Furthermore, security has become a key focus in automotive given the risk it presents to human and asset life. As external connectivity penetration grows in cars so does the security attack surface. A hacker may send fake messages and cause trouble to in-vehicle communications. Examples include enabling/disabling the car, displaying incorrect navigation information, turning on/off lights, distracting the driver with audio, generating false dashboard alerts, or taking over complete control of the car. These threats make placing security mechanisms imperative in system design. JEDEC, the standards body for UFS, has introduced support for inline encryption preventing eavesdropping and man-in-the-middle attacks native to the specification. Robust encryption mechanisms are proposed to allow for standardization across host and device combinations. Encryption scheme support is a key differentiator between UFS and eMMC making the former more appropriate for ADAS and black-box implementations.

In summary, UFS, the most favored data storage in smartphones, is also the clear winner to support storage requirements in modern software-defined vehicles.