UNIVERSAL FLASH STORAGEUNIVERSAL FLASH STORAGE (UFS) IS A COMMON FLASH STORAGE SPECIFICATION FOR PORTABLE DEVICES BY JEDEC.

PREPARED BY: BHAUMIK BHATT

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

HISTORY OF MASS STORAGE

• Memory storage market has been flooded with a plethora of different types of cards for different portable devices. So far, as we have seen, Secure Digital (SD) card specification by SanDisk has been tremendously popular and has gained wide-spread adoption.

• However, there are different cards that still exist. Examples: Compact Flash (CF) cards and XD picture cards for digital cameras, and so on.

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

UNIVERSAL FLASH STORAGE

• JEDEC stands for Joint Electron Device Engineering Council. It is now known as JEDEC Solid State Technology Association. JESD220A v1.0 made released in 2011. JESD220A v1.1 released in June 2012. JESD220B v2.0 announced September 2013.

• Being a common flash specification, UFS specification aims to is to bring high data rates, increased reliability and a subsequent reduction in market confusion with a plethora of existing flash cards.

• The proposed specification is backed by leading firms such as Nokia, Sony Ericsson, Texas Instruments, STMicroelectronics, Samsung and Micron.

• Toshiba was the first to announce 64 GB UFS Nand (v1.1) embedded storage to enable chipset and OS vendors to develop the interface for the emerging standard. Mass production, as stated by Toshiba, begins Q2 of 2014 for V 2.0.

• UFS supports both removable cards and embedded packages.

• UFS is NOT backwards compatible to the eMMC.

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

UNIVERSAL FLASH STORAGE

• Growth in mobile personal computing key to future demand & requirements… UFS is designed from the ground-up to meet the future mobile platforms needs.

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

ADVANTAGES IN COMPARISON TO EMMC• High speed serial interface compared to eMMC, which is a parallel interface.

• Ease of integration into embedded applications.

• Full duplex read/write operations.

• Uses the SCSI architectural model, unlike eMMC.

• Overall low power consumption, due to faster read/write operations and more idle time.

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

MEMORY INTERFACE SPEED TREND

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

UFS ARCHITECTURE

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

ELECTRICAL INTERFACE (PHYSICAL LAYER)

• UniProSM (or Unified Protocol) is a high-speed interface technology for interconnecting integrated circuits in portable devices, with support for UFS.

• UFS uses the MIPI M-PHY electrical interface, supported by Versions 1.4 and beyond of UniPro physical layer.

• UFS uses MIPI M-PHY as the physical layer and MIPI UniPro as the link layer.

• With SCSI architecture model, asynchronous operation and command queuing for increased random read/write speeds can be leveraged.

UniPro interconnection schematic

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

UFS V1.1 TEST-BED (TOSHIBA)

• Toshiba's comprehensive UFS 'ecosystem' brings together a UFS memory device, UFS host controller IP and UFS software drivers. 

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

CONCEPTUAL BLOCK DIAGRAM• UIC is the lowest layer of UFS layered architecture. It handles

connection between UFS host and UFS device.

• UTP transports messages through UFS protocol information unit(UPIU).

• Application layer handles SCSI commands supported by the UFS specification.

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

COMMAND FLOW

• HCI processes 3 types of commands in the following priority

• Interconnect layer commands

• Transfer request

• Transfer management request

• These are transferred in the form of a UFS Protocol Information Unit between Host and device.

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

OVERALL UFS SPECIFICATION ARCHITICTURE

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

COMMAND QUEUING MECHANISM

• 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.

 • The UFS HCI specification and

the adoption of SCSI provide a well-known software programming model and are enabling wider market adoption. 

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

SUPPORT FOR EMBEDDED AND REMOVABLE MEDIA AND POSSIBLE CHALLENGES• Reduced IP licensing and hardware cost by sharing same protocol and same port

(PHY)

• Problem: Latency increase for memories located further down the chain.

• Ways to deal with it?

• Lightly use communication links to avoid contention in the upstream and downstream bus.

• Host controller needs to send as many read/write requests to memories for maximum Bandwidth.

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

ADOPTION

• The e-MMC market size and momentum will likely mean that these two mobile embedded solutions will continue to be supported in parallel for some time, with UFS initially supporting the needs of applications demanding higher performance, and typically at higher densities, and e-MMC supporting the needs of applications driven to maintain the lowest cost.

• Qualcomm Snapdragon 805 with UFS support in works.

• The Universal Flash Storage Association (UFSA) was founded in 2010 as an open Trade Association to promote widespread industry adoption and acceptance of the UFS standard.

UNIVERSAL FLASH STORAGE - ECEN5613 - BHAUMIK BHATT

REFERENCES• JEDEC eMMC STANDARD JESD84-B50

• JEDEC UFS STANDARD JESD223-B for HCI

• http://universalflash.org/

• http://www.jedec.org/news/pressreleases/jedec-publishes-universal-flash-storage-ufs-standard-v20

• http://www.toshiba-components.com/ufs/

• http://www.toshiba.com/taec/news/press_releases/2014/memy_14_701.jsp

• http://www.arrowdevices.com/blog/how-did-jedec-ufs-beat-the-mipi-csi3-and-dsi2-in-adoption-race/

• http://www.datalight.com/solutions/technologies/emmc/comparing-emmc-to-other-flash-media

• http://superuser.com/questions/594357/ssd-sd-emmc-raw-nand-what-are-the-differences

• https://www.kernel.org/doc/Documentation/scsi/ufs.txt

• http://en.wikipedia.org/wiki/Universal_Flash_Storage

• http://en.wikipedia.org/wiki/UniPro

• http://www.jedec.org/

• http://www.techonline.com/electrical-engineers/education-training/tech-papers/4132750/Spansion-Methodologies-of-Optimizing-Future-Memory-Systems

• http://www.ubergizmo.com/2010/10/samsung-universal-flash-storage-ufs-memory-card-being-developed/

• http://vimeo.com/72052801