Development history of USB 3.0 and USB connectors

The USB 3.0 Promoter Group, composed of industry giants such as Intel, Microsoft, HP, Texas Instruments, NEC, ST-NXP, announced today that the new generation USB 3.0 standard developed by the organization has been officially completed and publicly released. The new specification provides a transfer speed ten times faster than USB 2.0 and higher energy efficiency, which can be widely used in PC peripherals and consumer electronics products.

Although USB 2.0 interface has become ubiquitous in the computer industry, just like traditional DVD players, as technology advances, we also need more realistic and clear high-definition images. Similarly, in computers, we also hope to obtain an interface with faster data transmission rates. On November 26, 2008, the USB Promotion Committee officially announced to the world that the next generation USB 3.0 interface specification had been developed!

USB 3.0 will support data transfer speeds of up to 5.0Gb/s. It is almost 10 times larger than the traditional USB 2.0 interface. Although the current USB 2.0 interface has been branded as "high-speed USB", the USB Promotion Committee has still come up with a new top-level USB 3.0 specification. After intense discussions, they finally defined this interface as the "SuperSpeed USB" ultra high speed USB interface.

The completed USB 3.0 standard has been handed over to the management organization USB Implementers Forum (USB-IF) for this specification. The organization will collaborate with hardware manufacturers to jointly develop new hardware that supports the USB 3.0 standard, but the actual product launch will take some time.

The IEEE organization recently approved the new specification IEEE1394-2008, but the new version of FireWire has a transmission speed of only 3.2Gb/s, which is slightly over 60% of USB 3.0. No wonder industry manufacturers such as Apple have generally lost interest in this technology.

USB 2.0 is based on a half duplex two-wire bus and can only provide unidirectional data stream transmission, while USB 3.0 adopts a dual simplex four wire differential signal line, which supports bidirectional concurrent data stream transmission. This is also the key reason for the rapid increase in speed of the new specification.

In addition, USB 3.0 also introduces a new power management mechanism that supports standby, sleep, and pause states.

Tektronix, a major measurement instrument manufacturer, was the first to announce a testing tool for USB 3.0 last month, which can help developers verify compatibility between new specifications and hardware designs.

USB 3.0 will be referred to as "USB SuperSpeed" in practical device applications, following the previous USB 1.1 FullSpeed and USB 2.0 HighSpeed. It is expected that commercial controllers supporting the new specifications will be launched in the second half of 2009, and consumer grade products are expected to be launched in 2010.

The first version of USB 1.0 appeared in 1996, with a speed of only 1.5Mb/s; Two years later, it was upgraded to USB 1.1 and the speed was greatly increased to 12Mb/s. To this day, this standard interface can still be seen on some old devices; In April 2000, the widely used USB 2.0 was launched, with a speed of 480Mb/s, which is forty times faster than USB 1.1; Now, eight and a half months have passed, and the speed of USB 2.0 is no longer sufficient to meet application needs. USB 3.0 has emerged, with a maximum transmission bandwidth of up to 5.0Gb/s, which is 625MB/s, and is backward compatible when using A-type interfaces.

USB 0.7:1994 was released in November.

USB 0.8: Released in December 1994.

USB 0.9: Released in April 1995.

USB 0.99: Released in August 1995.

USB 1.0 RC: Released in November 1995.

USB 2.0 Era

Increase the data transmission rate by 480 Mbit/s (now called Hi Speed). Further improved USB specifications based on Engineering Change Notices (ECN). The most important ECN specifications in USB 2.0 can be found on USB.org:

Mini-B Connector ECN: Released in October 2000. Standardized the plug and socket standards for Mini-B. Be careful not to confuse with Micro-B plugs and sockets.

Errata as of December 2000: Released in December 2000.

Pull up/Pull down Resistors ECN: Released in May 2002.

Errata as of May 2002: Released in May 2002.

Interface Associations ECN: Released in May 2003. Add new descriptors to associate multiple interfaces within a single device functionality.

Rounded Chamfer ECN: Released in October 2003. A suggested and compatibility improvement for the robustness of the Mini-B interface.

Unicode ECN: Released in February 2005. This ECN specifies that strings can be encoded using UTF-16LE. USB 2.0 specified the use of Unicode, but did not specify the encoding.

Inter Chip USB Supplement: Released in March 2006.

On The Go Supplement 1.3: Released in December 2006. USB On The Go allows two USb devices to communicate directly with each other without going through a separate USB host. In actual use, one of the USB devices serves as the host for other devices.

Battery Charging Specification 1.0 was released in March 2007. Added support for chargers (power adapters with USB interfaces), which allow for instantaneous passing of 100 mA current when the power supply end (serving as the USB main port of the charger) is connected to the battery. If a USB device is connected to a dedicated charger or main port, the maximum instantaneous current can reach 1.5 A. (This document is not included in the USB 2.0 specification.)

Micro USB Cables and Connectors Specification 1.01 was released in April 2007.

Link Power Management Addendum ECN: Released in July 2007. A new power mode has been added between enable and standby. When the device is in this mode, no commands are sent to it to reduce power consumption. So, switching between active and sleep modes is much faster than switching between active and standby modes.

The technical specifications for USB 3.0 were released on August 13, 2008, and its commercial products are expected to be released in 2009 or 2010. USB 3.0 has added 5 new contacts, two for data output and two for data input, using a send list section for data transmission. The new contacts will be placed side by side behind the current 4 contacts. The tentative power supply standard for USB 3.0 is 900mA and will support fiber optic transmission. The design of USB 3.0 is compatible with USB 2.0 and USB 1.1 versions, and uses more efficient protocols to save energy.