Embedded Universal Flash Storage (eUFS) solutions have been used in a variety of mobile applications since early 2015, when Samsung introduced 128-GB embedded memory based on the JEDEC UFS 2.0 standard. This week, Samsung unveiled the industry’s first eUFS solution for automotive applications. Coming in 128-GB and 64-GB versions, the new eUFS chips are aimed at infotainment systems, advanced driver-assistance systems (ADAS), and dashboards (Fig. 1).
1. The eUFS memory developed by Samsung will come in 128- and 64-GB versions. (Source: Samsung)
Automotive applications typically use embedded multimedia cards (eMMCs) to store information. A managed NAND (managed meaning a solution consists not only of NAND flash memory, but also a controller/interface circuit) eMMC remains the primary memory solution for consumer electronics, including tablets, smartphones, GPS systems, eReaders, and other mobile computing devices.
eUFS vs. eMMC
Configured on the JEDEC UFS 2.1 standard, eUFS provides sequential read/write speeds fast enough to rival solid-state disks (SSDs) while combining it with the low power consumption of an eMMC. For example, the new 128-GB eUFS can read data at up to 850 MB/s, which is approximately 3.4 times faster than the 250-MB/s read speed of today’s eMMC 5.0 solutions, and has a random reading speed of 45,000 I/O operations per second. Another characteristic is that although eUFS is identical in size to eMMC, it has twice the storage capacity.
eUFS differs from eMMC in that it has a low-voltage differential signaling (LVDS) serial interface, which has separately dedicated read/write paths. This allows for full duplex (two-way interaction), so that UFS can read and write simultaneously (Fig. 2). eMMC, on the other hand, has a parallel interface that can only send data in one direction at a time; it can either read or write, but not at the same time.
In addition, a Command Queue (CQ) in eUFS arranges the commands that need to be carried out. As a result, multiple commands can be addressed at the same time, and the order of tasks are able to be changed as needed. Without CQ, eMMC needs to wait for a process to be completed before moving on to the next one.
2. Unlike eMMC, UFS can read and write simultaneously. (Source: Samsung)
The new eUFS solution also features a reliable error-handling process, which is essential for next-generation in-vehicle infotainment. Based on the MIPI UniPro (Unified Protocol), eUFS enables detecting and recovering from I/O error on hardware layers without having to involve the host software or restarting tasks.
MIPI’s UniPro is a transport layer (for more on UniPro, check out this article). When implemented on top of M-PHY, it forms the UniPort-M interface. UniPort-M can be used with MIPI or non-MIPI interfaces. It simplifies the interconnection of peripherals and reduces time-to-market and design costs.
One of UniPro’s key technical characteristics is its ability to support various traffic classes. This feature can be used, for example, to deliver traffic across the interface in real time or non-real time. UniPro also supports networking of various connected devices, enabling designers to define the type of data traffic used for individual components. The current version of UniPro, v1.61, was released in 2015.
According to Samsung, eUFS meets the JEDEC UFS 2.1 standard as well as the upcoming JEDEC UFS 3.0 standard, and has the requisite data-refresh and temperature notification features. The latter feature works via a controller that prevents the UFS product from crossing well-defined upper and lower temperature boundaries. A heat-resisting capability is important for NAND memories in cars due to heat that’s produced from an engine and during driving. In this case, Samsung Electronics added a sensor that can detect temperature inside of eUFS’s internal controller, which is critical in difficult automotive temperature environments.
Overall, Samsung expects eUFS will contribute to significantly enhanced performance in automotive infotainment systems to better manage audio content, increase navigation responsiveness, access Internet-enabled traffic and weather reports, improve handling of hands-free voice commands, and speed up rear-seat social-media interplay.