Universal Flash Storage: Mobilize Your Data

Yuping Chung Mobile Storage Product Manager

The explosive growth in portable devices over the past decade continues to challenge manufacturers wishing to add memory to their products that meet these four basic criteria:

  • High bandwidth
  • High capacity
  • Low power
  • Low cost

Flash storage technology and standards have evolved rapidly to meet these requirements. Universal Flash Storage (UFS) was created for mobile applications and computer systems requiring high performance and low power consumption. These systems typically use embedded Flash based on the JEDEC standard eMMC. UFS was defined by JEDEC as the evolutionary replacement for eMMC offering significantly higher memory bandwidth. UFS uses a layered architecture as specified in JEDEC standard 220A. The upper layers in the standard were defined by the JEDEC while lower layers in the protocol where adopted from existing MIPI UniProSM and M-PHY standards. Intended for applications requiring large storage capacity for data and bootable code, UFS offers a simple, but high-performance, serial interface that efficiently moves data between a host processor and mass storage devices. The UFS standard adopts the well-known SCSI Architecture Model and command protocols supporting multiple commands with command queuing features and enabling a multi-threaded programming paradigm. This differs from conventional flash-based memory cards (eg eMMC) and embedded flash solutions which process one command at a time, limiting random read/write access performance. In addition, a complementary UFS Host Controller Interface (HCI) specification allows system designers greater flexibility by simplifying the involvement of the host processor in the operation of the flash storage subsystem. The adoption of SCSI provides a well-known software- programming model and enables wider market adoption. It provides a standard programming interface for UFS by enabling the use of common Host/OS drivers and a common register set for the OS driver as well as a low-level driver, which can be customized as necessary for the HW host controller. It gives optimized support for various UFS usage models with regards to embedded mass storage memory card and UFS bus topology. Arasan is actively supporting UFS IP solutions and development environment. Do sign in to access the UFS White Paper by Yuping Chung, Arasan’s Mobile Storage Product Manager.