Universal Flash Storage (UFS)

Universal Flash Storage

UFS is specifically tailored for mobile applications and computing systems requiring high performance and low power consumption. In September 2013, JEDEC published JESD220B UFS 2.0, which is an update to the v1.1 standard published in 2012. JESD220B Universal Flash Storage v2.0 offers increased link bandwidth for performance improvement, a security features extension as well as additional power saving features over the prior version. The new standard may be downloaded free of charge (with registration) from the JEDEC website.

Click here for an interesting perspective on market adoption of UFS 2.0.

Simplifying Design, Reducing System Cost & Improving Device Performance

JEDEC has also published four complementary standards; all are available for free download:

  • JESD220-1 UFS Unified Memory Extension
  • JESD223B UFS Host Controller Interface (UFSHCI) version 2.0
  • JESD223-1 UFS Host Controller Interface (UFSHCI), Unified Memory Extension
  • JESD224 UFS (Test)

JESD223B is intended to simplify the design process by defining a standard host controller interface on which system designers can create a common host controller software driver layer to work with UFS host controller hardware from different manufacturers.

JESD220-1 and JESD223-1 define the interface between the UFS driver and the UFS host controller, as well as data structures inside the system memory which are used to exchange data, control and status information.

JESD224 defines standard test cases and procedures for measuring the behavior of UFS devices and comparing that with the requirements of the UFS standard.

To achieve the highest performance and most power efficient data transport, JEDEC UFS aligns with industry–leading specifications from the MIPI® Alliance to form its Interconnect Layer. This collaboration continues with UFS v2.0, which supports the M-PHY® Version 3.0 specification and the UniProSM Version 1.6 specification.  

For more information about MIPI specifications related to UFS, visit: http://www.mipi.org/about-mipi/industry-associations/jedec-solid-state-technology-association.
UFS Background

First published in February 2011, UFS is designed to be the most advanced specification for both embedded and removable Flash memory-based storage in mobile devices such as smartphones and tablets. The initial data throughput for UFS is 300 megabytes per second (MB/s) over the bus in both uplink and downlink directions simultaneously, without infringing on bandwidth needed for other applications. UFS offers a low active power level and a near-zero idle power level, which, combined with the power-saving attributes of the related MIPI specifications, allows for significant reductions in device power consumption. The UFS standard adopts the well-known SCSI Architecture Model and command protocols supporting multiple commands with command queuing features and enabling a multi-thread programming paradigm. This differs from conventional Flash-based memory cards and embedded Flash solutions which process one command at a time, limiting random read/write access performance. The UFS HCI specification and the adoption of SCSI provide a well-known software programming model and are enabling wider market adoption. 

Work on UFS is coordinated by JEDEC's JC-64 Committee for Embedded Memory Storage and Removable Memory Cards, and is supported by principal consumer electronic and cell phone OEMs. In addition to UFS development work within JEDEC, some major participants have founded an organization, the Universal Flash Storage Association (UFSA), to develop an UFS ecosystem and support environment for UFS devices and host applications.

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Contact Julie Carlson, 703-624-9230