USB to SATA3 bridge supports UASP

September 05, 2011 // By Phil Ling
The SuperSpeed Universal Serial Bus (USB 3.0) SATA3 bridge system-on-chip ([SoC] from Renesas enables data transfer between a USB3.0 host system and a Serial ATA (SATA) device in external USB storage equipment. The new SoC is claimed to be the world's first USB 3.0 Bridge SoC that supports the UASP (USB Attached SCSI Protocol).

In response to the need for even faster data transfer performance necessary with the increased scale of the data handled in the storage device market, Renesas has released the µPD720230 bridge SoC. This device, combined with its host-controller technology and UASP driver software, achieves industry-leading data transfer performance, according to the company.

In addition to working with its USB 3.0 host controllers, the UASP driver operates with AMD’s A70M and A75 chipsets, which has been made possible through close cooperation with AMD. Renesas also plans on achieving compatibility with AMD’s future USB3-supporting chipsets.

Key features of the new µPD720230 SoC include support for SATA Revision 3.0, which enables 6 Gbps high-speed data transfer, SuperSpeed USB transfer speeds of up to 5 gigabits per second (Gbps)—as well as the SATA Revision 3.0 6Gbps bit rate achieving maximum data transfer performance of USB 3.0. Support for both the UASP and BOT protocols achieves data transfer performance that exceeds 370 megabytes per second (MB/s) in UASP mode.

In addition to the BOT standard for mass storage devices using USB 2.0, it also supports the UASP protocol standardized in USB 3.0 for improving the performance limits of the BOT standard. When connected to an SSD that supports 6 Gbps SATA3, the µPD720230 device achieves data transfer performance in excess of 370 MB/s in UASP mode as verified by the ATTO Disk Benchmark, version 2.46.

Although only two states, the U0 normal state and the U3 suspend state were stipulated in the USB 2.0 standard, the USB 3.0 standard also stipulates the U1 and U2 power states to provide even finer-grained suppression of power consumption. The new USB 3.0 SATA3 SoC reduces overall power consumption by approximately 40 percent (when the system is in the idle state) via the new USB 3.0 U1 and U2 power states, as compared to when stipulating only the U0 and U3 power states..

Renesas’ UASP driver is also available