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The connection and difference between USB2.0 and USB3.0
Time:2020-12-30Click volume:

1. What is USB 3.0?

USB 3.0 is the latest USB specification, which was initiated by large companies such as Intel. At present, USB 2.0 has been generally recognized by PC manufacturers, and the interface has become a must-have for hardware manufacturers. Look at the commonly used motherboards at home. With the continuous development and progress of hardware devices, higher transmission speeds and larger bandwidths are increasingly being valued by people. The transmission speed of 2,300M per second will become more and more difficult for people to settle for the status quo. In 2007, Intel presented SuperSpeed USB as an important topic on IDF. It was not until November 17, 2008 that the USB 3.0 standard was officially completed and publicly released. At the same time, the new USB Implementers Forum (USB-IF) also officially began to take over and operate the specification, and announced detailed technical documents so that hardware manufacturers in the industry can develop USB 3.0-related products accordingly. The brief specifications of USB 3.0 are as follows: · Provides a higher transmission speed of 4.8Gb per second · Provides better support for devices that require greater power support, maximizes the power supply of the bus · Adds new power management functions· Full-duplex data communication, providing faster transmission speed, backward compatible with USB 2.0 devices

2. Is it faster than USB 2.0? USB 2.0 provides sufficient bandwidth for various devices and applications. However, with the advent of high-definition video, TB (1000GB) storage devices, digital cameras up to gigapixels, large-capacity mobile phones and portable media players , Higher bandwidth and transmission speed have become a must. The transmission speed of 480Mb per second may not be too fast, not to mention that there is no USB 2.0 device that can reach the theoretical maximum speed limit. In practical applications, it is very good to be able to reach an average speed of 320Mb per second. Similarly, in fact, USB 3.0 cannot reach the theoretical value of 4.8Gb, but even if it can only reach 50% of the theoretical value, it is close to 10 times that of USB 2.0. How does USB 3.0 make it so fast? The "super-speed" performance of USB 3.0 is entirely due to technological improvements. Compared with the current USB 2.0 interface, USB 3.0 adds more physical buses in parallel mode. Readers can pick up a USB cable next to you and look at the interface part. On the basis of the original 4-wire structure (power, ground, 2 pairs of data), USB 3.0 adds 4 more lines for receiving and transmitting signals. Therefore, there are a total of 8 lines whether in the cable or on the interface. It is the additional 4 (2 pairs) lines that provide support for the bandwidth required by "SuperSpeed USB", enabling "SuperSpeed" to be achieved. Obviously, two (1 pair) lines on USB 2.0 are not enough. In addition, the method of signal transmission is still controlled by the host, but it is changed to asynchronous transmission. USB 3.0 utilizes a two-way data transmission mode instead of the half-duplex mode of the USB 2.0 era. Simply put, data only needs to flow in one direction, which simplifies the time consumption caused by waiting. In fact, USB 3.0 does not adopt any advanced technology that we rarely hear, but theoretically increases the bandwidth by 10 times. Therefore, it is more affinity and friendliness. Once SuperSpeed USB products come out, more people can easily accept and make better customized products.

3. What are the more advanced aspects of USB 3.0? The improvement of "SuperSpeed USB" goes far beyond the increase in transmission rate. In USB 3.0, how to cooperate more harmoniously between the device and the computer host is also regarded as a key research direction. On the basis of inheriting the core architecture of USB 2.0, how to take advantage of the dual bus mode and how to allow users to directly experience the advancement of USB 3.0 over USB 2.0 has become the focus: · Provide more power when needed. USB 3.0 can provide 50%-80% more power supports devices that require more power to drive, and those devices that are charged via USB indicate that charging can be completed faster. The new Powered-B interface consists of two additional lines, providing power support up to 1000 mA. It can drive the wireless USB adapter completely, and get rid of the need for the traditional USB adapter to be connected by a cable. Usually wired USB devices need to be connected to a hub or the computer itself, and with the support of high power, there is no need for a "wire" to exist. ·Automatically reduce power consumption and switch to USB 3.0 when not needed. Power consumption is also a very important issue to consider. Therefore, effective power management is necessary to ensure that the device is idle to reduce power consumption. The transmission of a large number of data streams requires faster performance support. When transmitting at the same time, the device can switch to a low power consumption state when it is idle. It can even be free to receive other instructions and complete other actions.

 4. How long is good? In fact, not everything in USB 3.0 has been updated, such as the length of the cable. When the highest possible throughput is required in certain applications, cables are often still a bottleneck. Although the USB 3.0 specification does not clearly specify how long the USB cable is, the cable material and signal quality still affect the transmission effect. Therefore, when transmitting hundreds of megabytes of data, the cable length should not exceed 3 meters. In addition, some hardware products that support "SuperSpeed USB", such as hubs, may be much more expensive than USB 2.0. This is like the principle of active power supply hubs and passive power supply. Because a real "SuperSpeed hub" should have two types of interfaces, one is used to play the role of the real "SuperSpeed hub", and the other is to play the role of an ordinary high-speed hub. There are some unofficial remarks on the Internet that USB 3.0 can use optical fiber. In fact, this is the issue that the USB specification organization is considering. It may be launched in the next revised version, or some capable third-party companies may try it. a bit.

5. USB 2.0 will still dominate the market within five years. Will my existing peripherals work properly? USB 3.0 has been cautiously hoping to co-exist with USB 2.0 from the beginning of its planning. USB 3.0 uses a new physical interface and a new cable to ensure a higher-speed connection with the new device, but the new interface maintains the same specifications as the 4-wire USB 2.0, and it can be connected to the existing USB interface. Only when the hardware of the device itself supports "SuperSpeed USB", 5 independent line groups can realize the true meaning of USB 3.0 and complete the function of receiving and sending data.


6. Where is USB 2.0 going? We will not see USB 2.0 related products exit the market for at least the next 5 years. Devices with high bandwidth requirements, such as digital cameras, large-capacity mobile hard drives and other products, will be the first to transition to "SuperSpeed USB" because of demand. However, due to cost reasons, the industry also depends on output and market demand. Therefore, it also limits the popularity of USB 3.0 in the high-end market. By 2010, the motherboard will first shift to a USB 3.0 interface, and the "SuperSpeed" specification interface will become standard on new PCs. At the same time, equipment manufacturers cannot passively transform to USB 3.0. Finally, USB 2.0 will be phased out like USB 1.1. However, in the foreseeable future, USB 2.0 related devices are still within reach.


7. What operating system can support USB 3.0? Windows Vista, Windows 7 and Linux already support USB 3.0. MAC does not support it yet. Steve Jobs is still on the sidelines and it will take some time.


8. What kind of applications can USB 3.0 drive? Simply put, all high-speed USB 2.0 devices can only have better performance when they get USB 3.0, at least not worse. These devices include: · External hard drives-at least twice the transmission speed, not to worry about insufficient power supply. ·High-resolution webcams, video monitors·Video displays, such as products using DisplayLink USB video technology·USB interface digital cameras, digital camcorders·Blu-ray drives, etc. USB 3.0 will promote the popularization of Blu-ray. In addition, our most commonly used reading Card device, especially when multiple types of flash memory cards are used in the device at the same time, or the card reader is connected to the USB Hub, and there are multiple card readers on the USB Hub, the transfer speed is simply difficult Endured torture. USB 3.0 provides more space to solve such problems. Providing 5-10 times the bandwidth is not a problem. Another point is predictable. Theoretically, the transmission speed of 4.8Gb per second is enough to allow USB to invade into the range that has never been dare to dare to dare before, such as the disk array system.


9. How about the market competition of USB 3.0? Potential competitors of USB 3.0: 1394, eSATA, low- and medium-speed peripherals outside the computer-no rivals. Computer external high-speed peripherals-1394 has high efficiency but high price. It is a high-end (price) product application. The general application market is occupied by USB HS applications. USB 3.0 applications have a good chance to replace 1394 in this application. The real-time image transmission of DV digital cameras-USB 2.0 requires PC operation and is inefficient. It is not equal to 1394. This market has long been occupied by 1394. USB 3.0 transmission is likely to enter this market. Growth trends and market share estimates-2.6 billion USB ports were shipped in 2007 alone. In-Stat senior analyst Brian O'Rourke said at a press conference: "It is estimated that USB 3.0 will be released from 2009 to 2012. The average annual growth rate will reach 100%, reaching 50 million shipments in 2012. "The market opportunity of USB 3.0 will greatly squeeze the space for other organic interface technologies. Time to market and acceptance---USB 3.0 products, which entered the market in mid-2009, began to have popularized products in 2010. Because they are fully compatible with the old version of the host and device, it can be estimated that their acceptance into the market is very high and The time is very fast.

10. What is the status of the USB 3.0 market? ■USB 2.0 provides sufficient bandwidth for various devices and applications. However, with the development of high-definition video, TB (1000GB)-level storage devices, digital cameras up to 10 million pixels, large-capacity mobile phones and portable media players Appeared, higher bandwidth and transmission speed became a must.

        ■The transmission speed of 480Mb per second may not be too fast, not to mention that no USB 2.0 device can reach the theoretical maximum speed limit. In practical applications, it is very good to be able to reach an average speed of 320Mb per second.

        ■Similarly, in fact, USB 3.0 also cannot reach the theoretical value of 5Gb. If it can only reach 50% of the theoretical value, it is also close to 10 times that of USB 2.0.

        ■The new "Superspeed USB" will be 10 times faster than the existing USB2.0, and the USB3.0 specification has entered the final stage of completion. Jeff Ravencraft, chairman of the USB Promotion Group, said that the maximum transmission speed of Superspeed USB will be 10 times that of USB 2.0, and the minimum transmission speed will reach 300MB/s.