USB 3.0 Superspeed cable
USB 3.0 is a USB specification that was initiated by companies such as Intel. It has been updated to USB 3.1 gen 1 by USB IF.
USB 2.0 has been widely recognized by PC manufacturers, and the interface has become a necessary interface for hardware manufacturers.
USB 2.0 has a maximum transmission bandwidth of 480 Mbps (ie 60 MB/s), while USB 3.0 has a maximum transmission bandwidth of up to 5.0 Gbps (640 MB/s).
Please note that the bandwidth of 5Gb/s is not 5Gb/s divided by 8 and 625MB/s. Instead, it uses the same 10-bit transmission mode as SATA (a pair of error correction codes are added to USB2.0). Its full speed is only 500MB/s. [2]
However, everyone should pay attention to this is the theoretical transmission value. If several devices share a USB channel, the main control chip will allocate and control the bandwidth that each device can control. As in USB 1.1, all devices can only share 1.5MB/s of bandwidth. If a single device occupies all the bandwidth of the USB interface, it will cause difficulties for the use of other devices.
Introduction to USB 3.0
USB 3.0 - also known as SuperSpeedUSB - provides a standard interface for a variety of devices connected to PCs or audio/high frequency devices. Just a hardware device, you can use USB3.0 related functions only after installing USB3.0 related hardware devices in your computer! From keyboards to high-throughput disk drives, a variety of devices can use this low-cost interface for smooth, plug-and-play connectivity, so users don't have to worry too much about it. The new USB 3.0 offers several enhancements while maintaining compatibility with USB 2.0:
● Greatly improved bandwidth - up to 5Gbps full duplex (USB2.0 is 480Mbps half duplex).
● Achieve better power management.
● Enables the host to provide more power to the device for USB—rechargeable batteries, LED lighting, and mini-fans.
● Enables the host to recognize the device faster.
● The new protocol makes data processing more efficient.
USB 3.0 can transfer large files (such as HD movies) at the storage rate defined by the storage device. For example, a flash drive with USB 3.0 can transfer 1GB of data to a host in 15 seconds, while USB 2.0 takes 43 seconds
Driven by the ever-increasing resolution and storage performance requirements of consumer electronics devices, it is hoped that wider media applications will be realized through broadband Internet connections, so users need faster transmission performance to simplify downloading, storage, and mass storage. Sharing of content. USB 3.0 plays a vital role in providing consumers with the easy connectivity they need.
When used in consumer devices, USB 3.0 will solve the problem that USB 2.0 does not recognize batteryless devices. The host can slowly reduce the current through USB 3.0 to identify these devices, such as those with a broken battery.
For system and ASIC developers, the wide availability of USB 3.0 chips and IP ensures that every design requirement can be met in a timely manner. This omni-directional support is especially important for standards like USB 3.0, because speed, advanced protocols, and various cable lengths (from a few inches to a few meters) make design and standard compatibility a challenge.
SATA and USB In the past few years, USB, eSATA and Firewire have achieved remarkable results in the personal computer field in the various device standards that are competing to become external memory interfaces. At this point, Serial ATA (SATA) replaces all other interfaces in the internal drive connectivity of consumer PCs. Although the new Compactflash version called CFast will be built on SATA, the earlier Parallel ATA (PATA) continues to be used in industrial and embedded applications that use CompactFlash as a storage medium.
Since its introduction in 2004, eSATA has challenged USB 2.0 and FireWire in external memory applications. eSATA transfers data to and from external devices at the same rate supported by SATA internal drives. It is worth mentioning that the eSATA interface can support data transmission rates of up to 3Gbps. Even with the actual rate reduced by encoding, eSATA's data rate is sufficient for the highest speed hard drive, which can transfer data at 12MB/sec (approximately 90Mbps).
Although eSATA is only used for memory applications, its performance allows it to capture the market share of USB 2.0 and FireWire. Other advantages of SATA include low processor costs. USB 3.0 performance is significantly better than eSATA and FireWire 800. At 5Gbps full-duplex, USB 3.0 is faster than full-duplex eSATA and FireWire 800, which can reach 800Mbps. (Note that eSATA's 3Gbps data is single-duplex, while USB 3.0 provides full-duplex. Although we can't elaborate here, it's still worth noting that USB 3.0 includes optional devices for Transferring out-of-order data is the best choice for disk-driven searches.)
Fujitsu's USB 3.0 - SATA chip solution
To implement an easy way to use SATA hard drives for USB 3.0, Fujitsu has introduced the MB86C30A single-chip solution to bridge USB 3.0 and SATA/ATA/ATAPI-based mass storage. This bridge chip transfers the mass storage requirements of USB 2.0 and USB 3.0 to the SATA and ATA/ATAPI communication protocols.
The MB86C30A is the world's first USB 3.0 slave chip, using Fujitsu's high-speed serial I/O technology.
In the near future, chips built with 65nm CMOS technology will achieve lower power consumption and greater flexibility in adopting high-speed USB specifications.
Fujitsu has demonstrated its USB 3.0 slave chip at the "2009 SuperSpeed USB Developer Conference" and has proven it has the industry's fastest transfer rate.
This chip meets the requirements of USB 3.0 specification 1.0 and SATA specification 2.6 released in November 2008.
The chip also complies with the USB Mass Storage bulk transfer protocol. Figure 1 shows the main functions of the chip. Official release of the USB 3.0 standard
The USB 3.0 Promoter Group 2008-11-18, which consists of IT giants such as Intel, Microsoft, Hewlett-Packard, Texas Instruments, NEC, and ST-NXP, announced that the next-generation USB 3.0 standard that the organization is responsible for has been officially completed and released. The new specification delivers ten times the transfer speed of USB 2.0 and higher energy efficiency, making it widely used in PC peripherals and consumer electronics.
The organization will work with hardware vendors to develop new hardware that supports the USB 3.0 standard, but the actual product
It will take a while to go public.
The first version of USB 1.0 appeared in 1996, the speed is only 12Mbps; after two years, it was upgraded to USB1.1, the speed has not changed, only the technical details have been changed, so the standard can still be seen on some old devices. The interface is widely used since April 2000. The speed of USB2.0 is 480Mbps, which is 40 times that of USB 1.1. Now 10 years have passed, the speed of USB 2.0 can no longer meet the application needs, USB 3.0 also It came into being, with a maximum transmission bandwidth of up to 5.0 Gbps, which is 500 MB/s, and is backward compatible when using the Type A interface. The IEEE organization has also approved the new specification IEEE1394-2008, but the new version of FireWire has a transfer speed of only 3.2 Gbps, which is equivalent to more than 60% of USB 3.0. It is no wonder that industry players such as Apple have generally lost interest in the technology.
USB 2.0 is based on a half-duplex two-wire bus, which can only provide one-way data stream transmission, while USB 3.0 uses a dual-simplex four-wire differential signal line, thus supporting bidirectional concurrent data stream transmission, which is also the speed of the new specification. The key reason.
In addition, USB 3.0 introduces a new power management mechanism that supports standby, hibernate, and pause states.
Tektronix, the largest measuring instrument, announced its first test tool for USB 3.0 last month to help developers verify compatibility between new specifications and hardware design.
USB 3.0 will be referred to as "USB SuperSpeed" in real-world device applications, conforming to previous USB 1.1 FullSpeed and USB 2.0 HighSpeed. Commercial controllers supporting the new specification are expected to be available in the second half of 2009, and consumer products are expected to be available in 2010.
Standard specification
Transmission rate
The actual transfer rate of this new ultra-high-speed interface is approximately 3.2 Gbps (ie 320 MB/s). The theoretical maximum rate is 5.0 Gbps (ie 500 MB/S).
data transmission
USB 3.0 introduces full-duplex data transmission. Two of the five lines are used to transmit data, two are used to receive data, and one is ground. In other words, USB 3.0 can read and write at full speed at the same time. Previous USB versions did not support full-duplex data transfer.
power supply
The USB 3.0 standard requires a USB 3.0 interface with a power supply of 1A and a USB 2.0 of 0.5A.
Power management
Instead of device polling, USB 3.0 uses an interrupt-driven protocol. Therefore, the standby device does not consume power until there is an interrupt request for data transmission. In short, USB 3.0 supports standby, hibernate, and pause states.
Physical appearance
The above specifications will also be reflected in the physical appearance of USB 3.0. But the USB 3.0 cable will be more "thick" because the USB 3.0 data cable has four more internal lines than the 2.0. However, this socket is a drawback of USB 3.0. It contains additional connected devices.
support system
Windows 3.0 is supported on Windows 10, Window 8.1, Window 8, Windows Vista, Windows 7 SP1, and Linux (and Linux-based Android). Apple's latest Apple Mac book air and Mac book pro are also supported. For XP systems, USB 3.0 can be used, but only at USB 2.0.
Appearance characteristics
USB3.0 and USB2.0 look different, observe the USB (self) socket and the USB socket on the computer, the middle plastic piece color: USB3.0 - blue; USB2.0 - black. Of course, some device colors are not standardized. For example, some non-native usb3.0 supported by the main control chip may not be blue. Some usb2.0 devices such as MP3, data cable, etc. may be black or white plastic tablets. .
If you can't distinguish by color, you can also see the number of interface pins. USB3.0 has a few more pins than USB2.0. On the Type-A interface, there are 5 more pins in the interface, and the Type-B interface has one more on the interface.
influences
From 12Mbps upgrade of USB 1.1 to 480Mbps of USB 2.0, the improvement rate has reached 40 times, and the upgrade from USB 2.0 standard to USB 3.0 standard is only 10 times, but the improvement of 10 times speed has great application significance, since USB 3.0 data transmission rate reached 4.8Gbps, far higher than other transmission standards, such as IEEE 1394 data transmission is usually between 400Mbps ~ 3.2Gbps, and the new generation of eSATA standard known as "USB mobile hard disk terminator" Only 3Gbps data transfer rate.
This is not the case, because IEEE 1394 and eSATA have their own application positioning. The IEEE 1394 standard has a maximum data transfer rate of 3.2 Gbps and is lagging behind USB 3.0 in speed. However, it provides point-to-point transmission, so that it does not depend on the PC. It can realize data transmission between devices, and supports synchronous and asynchronous transmission modes. It can connect 63 devices, can transmit digital video and digital audio signals at the same time, and has no signal loss during acquisition and recording, making IEEE1394 interface more suitable. Multimedia devices (such as DV machines, capture cards), these are unmatched by the USB 3.0 standard. Overall, the application of the IEEE 1394 interface is more professional and free. However, due to the lack of professionalism and vendor promotion, the popularity of IEEE 1394 devices is not high. Usually, a device has both an IEEE 1394 interface and a USB interface.
For the eSATA standard, it is actually an extension of the SATA interface, also known as an external SATA interface, which supports plug and play, but has great limitations in function. First, it does not support the power supply function, and must cooperate with the motherboard. The eSATA interface is used, which means that it can't get rid of the limitations of PC. It is generally only suitable for mobile hard drives, convenient DVD drives and TV boxes. It is useless for today's popular consumer digital electronic devices, so it is in USB 3.0. After the launch of the standard, eSATA is the transmission standard facing the most competitive pressure. However, it should be noted that since eSATA is derived from the SATA chip on the motherboard, it has a boot-up function. That is to say, the computer can be connected to an eSATA hard drive or an eSATA optical drive to boot the system, which is a troublesome USB hard drive and USB optical drive. This is important for system maintenance, server exchange of data under DOS data, but for the general public, the status and development of eSATA may end.
speed
USB 2.0 provides ample bandwidth for a wide range of devices and applications, but with high-definition video, TB (1024GB) class storage devices, up to 10 million pixel digital cameras, high-capacity mobile phones and portable media players The emergence of higher bandwidth and transmission speed has become a necessity.
The transmission speed of 480Mbps may not be too fast, not to mention that no USB2.0 device can achieve this theoretical maximum speed limit. In practical applications, the average speed of 320Mbps is already very good.
Similarly, USB 3.0 does not reach the theoretical value of 5.0 Gbps. If it can only reach 80% of the theoretical value, it is close to 10 times that of USB 2.0. The physical layer of USB3.0 adopts 8b/10b encoding mode, so the theoretical speed calculated is 4Gbps, and the actual speed is deducted from the protocol overhead, and there are fewer points on the basis of 4Gbps.
The new "Superspeed USB" will be 10 times faster than the existing USB 2.0, and the USB 3.0 specification has entered the final stage of completion. Jeff Ravencraft, chairman of the USB promotion group, said that the maximum transfer speed of Superspeed USB will be 10 times that of USB 2.0 and the minimum transfer speed will reach 300Mb/s. He will bring higher speed to flash products, using solid state hard disk, if the interface is from USB2.0 upgrade to 3.0, then the leap from the propeller to the jet. The cable and port of Superspeed USB will adopt the backward compatibility mode. Intel has abandoned the previous fiber interconnection as the transmission mode. It is understood that this is a cost saving, and the speed of USB3.0 is also satisfactory. The effect" without the need for in-depth development in this area. The USB3.0 interface is divided into two parts, one part uses the same pin as USB2.0; another series of electrical interfaces are added for USB3.0 signal transmission. There are already many USB3.0 products available, such as USB3.0 mobile hard disk, U disk, card reader, and so on.
We are talking about 5Gb/s, which refers to bits, not bytes. Since 8 bits are equal to 1 byte, just like you pull a 4Mbps network cable, the theoretical download speed can only reach 512KB/S. However, USB3.0 still has a problem: the encoding rule uses the 8/10 method, and there is a 2b control signal, so the theoretical data transmission rate of USB 3.0 is 5 Gbps/10 bitt=500 MB/s.
To reach the theoretical speed of 500MB/s, two bottlenecks must be broken: the motherboard interface and the storage medium. You rushed to the computer city, bought a USB3.0 mobile hard disk to try again, found that the speed of USB2.0, this bottleneck is likely to be on the motherboard interface. Fortunately, Intel has natively supported USB 3.0 in the latest 7 series chipsets. You can also bridge two blue USB 3.0 ports through a third-party USB3.0 host chip to unlock the motherboard speed bottleneck. .
Limited by the mechanical structure of the hard disk, the internal transmission speed of the mainstream 3.5-inch 7200-rpm 500G hard disk will not exceed 150MB/S, and the internal transmission speed of the 2.5-inch 5400-rpm 500G mobile hard disk is lower. The so-called USB 3.0 USB flash drive, the speed bottleneck lies in the main control and FLASH chip used.
Aside from the theoretical speed of USB3.0, the actual transfer speed of USB3.0 interface products is: read speed is 60MB/s to 140MB/s, and write speed is 50MB/s to 90MB/s. Many so-called USB3.0 USB flash drives and hard disks on the market have faster reading speeds, but the writing speed may be very low. In addition, if the mobile hard disk is a USB2.0 interface, and it is connected with the PC USB3.0 interface to transmit data, then the theoretical maximum transfer rate is 60MB/S of USB2.0.
On the morning of January 7, 2013, USB3.0 promotion organization announced at the Consumer Electronics Show (CES) on Sunday that the first batch of USB3.0 devices with a transmission rate of 10Gbps will be available in 2014, which will be faster. The current 5Gbps is almost twice as fast.
working principle
The reason why USB 3.0 has "speeding" performance is entirely due to technical improvements.
Compared to the USB 2.0 interface, USB 3.0 adds more parallel mode physical buses.
You can pick up a USB cable around you and look at the interface section.
Based on the original 4-wire structure (power, ground, 2 data), USB 3.0 adds 4 more lines for receiving and transmitting signals.
So there are a total of 8 lines in either the cable or the interface.
It is the additional four (2 pairs) lines that provide the bandwidth required for the “SuperSpeed USB” to achieve “overspeed”.
Obviously two (1 pair) lines on USB 2.0 are not enough.
In addition, the method of signal transmission still uses the host control method, but it is changed to asynchronous transmission.
USB 3.0 takes advantage of the two-way data transfer mode and is no longer the half-duplex mode of the USB 2.0 era. Simply put, data only needs to flow in one direction, simplifying the time consumption caused by waiting.
In fact, USB 3.0 did not take any sensible technology, but theoretically increased the bandwidth by 10 times. It is therefore more affinitive and friendly. Once the SuperSpeed USB product is available, it will make it easier for more people to accept and make better customized products.
Advanced
The "SuperSpeed USB" improvement goes far beyond the transfer rate. In USB 3.0, how to better coordinate the device and the host computer is also regarded as a key research direction. On the basis of inheriting the USB 2.0 core architecture, how to take advantage of the dual bus mode, how to enable users to directly experience the advanced USB 3.0 than USB 2.0, has become the focus:
Provide more power when needed
USB 3.0 can provide 50%-80% more power to support devices that require more power to drive, while those that charge via USB indicate a faster charging.
The new Powered-B interface consists of an additional 2 lines that provide up to 1000 mA of power. It is completely capable of driving the wireless USB adapter, and it is necessary to get rid of the connection of the traditional USB adapter by cable. Usually wired USB devices need to be connected to the hub or the computer itself, and with high power support, there is no need to have a "line".
Automatically reduce power consumption when not needed
Switching to USB 3.0, power consumption is also an important issue to consider, so effective power management is necessary to ensure that power consumption is reduced when the device is idle.
A large amount of data stream transmission requires faster performance support, and at the same time, when transmitting, the device can go to a low power state when idle. You can even go empty to receive other instructions and complete other actions.
In fact, not all things are updated in USB 3.0, such as the length of the cable. When the highest possible throughput is required in some applications, cables often become bottlenecks. Although in the USB 3.0 specification, there is no explicit specification of how long the USB cable is, cable material and signal quality still affect the transmission. 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, which is a reason for active power hubs and passive power supplies. Because a true "SuperSpeed hub" should have a type 2 interface, one to play the role of a true "SuperSpeed hub", and the other to play the role of a normal high-speed hub.
There are some unofficial comments on the Internet that talk about the use of fiber optics in USB 3.0. In fact, this is exactly what the USB specification organization is considering. Maybe it will be released in the next revised version. Maybe some competent third-party companies will try it out. .
operating system
Kāiyuán xìtǒng fāngmiàn, Linux míngquè de biǎoshì zhīchí USB 3.0, Qiántí shì kuòzhǎn zhǔ kòngzhì qì jièmiàn (xHCI) guīfàn zhèngshì fǎ bù. Fēi gōngkāi bǎnběn hào wèi 0.95, Háishì yīgè dàidìng de cǎo'àn.
Píngguǒ fāngmiàn, zài 2012 nián zhōng fābù de xīn jī yǐ quánmiàn gǎi yòng USB 3.0 Jiēkǒu.
Zhìyú duì Firewire xìnhào shìfǒu cúnzài gānrǎo wèntí, hái bùdé ér zhī, dànshì bùguǎn zěnyàng, píngguǒ xūyào qù zhīchí “SuperSpeed”, rúguǒ suǒyǒu rén dōu kànhǎo zhège jiēkǒu biāozhǔn dì huà.
Qǐchū, zài USB 3.0 De zhīchí fāngmiàn, bùguǎn shì cāozuò xìtǒng háishì shèbèi, kěndìng bù huì yībù dàowèi. Chūqí huì jiǎndān de zài xiǎoxíng shèbèi shàng shìyòng, ránhòu cúnzài zhèyàng nàyàng de wèntí, bìngqiě hái bù huì quánmiàn fāhuī USB 3.0 De yōushì. Bùguò, suízhe shíjiān de tuīyí, zhèxiē dūhuì zhúbù de wánshàn qǐlái.
Qǐng zhùyì,Vista bù nénggòu shǐyòng Intel zhǔ kòng de USB 3.0 Jiēkǒu (Intel bìng wèi zhēnduì Vista tígōng qūdòng), rúguǒ xūyào zài Vista shàngmiàn shǐyòng USB3.0, Qǐng shǐyòng qítā chǎng pái de zhǔ kòng.
On the open source system side, Linux explicitly supports USB 3.0, provided that the Extended Host Controller Interface (xHCI) specification is officially released. The non-public version number is 0.95, which is still a pending draft.
For Apple, the new machine released in mid-2012 has been completely switched to the USB 3.0 interface.
As for whether there is interference with the Firewire signal, it is not known, but in any case, Apple needs to support "SuperSpeed" if everyone is optimistic about this interface standard.
At first, in terms of USB 3.0 support, whether it is an operating system or a device, it will definitely not be in one step. Initially, it will be simple to try on small devices, and then there are problems like this, and the advantages of USB 3.0 will not be fully realized. However, as time goes by, these will gradually improve.
Please note that Vista is not able to use the Intel 3.0 USB interface (Intel does not provide drivers for Vista), if you need to use USB3.0 on Vista, please use the other brand's master.
These devices include:
External hard drive - at least twice the transfer speed, not to worry about the lack of power;
High resolution webcam, video monitor;
Video displays, such as those using DisplayLink USB video technology;
Digital camera and digital video camera with USB interface;
Blu-ray drive, etc.
In addition, the most commonly used card reader devices, especially when multiple types of flash cards are used simultaneously in the device, or when the card reader is connected to the USB Hub, and there are multiple card readers on the USB Hub, then The transmission speed is simply an unbearable torment.
USB 3.0 provides more space to solve such problems, providing 5-10 times the bandwidth is not a problem.
Another point is that it is foreseeable that theoretically 4.8Gb per second is enough to allow USB to invade the range that was never dare to be used before, such as disk array systems.
USB 3.0 is backward compatible with USB 1.1 and USB 2.0 standards, with the ease of use and plug-and-play functionality of traditional USB technology. The goal of USB 3.0 technology is to launch products that are 10 times faster than USB 2.0, using the same architecture as wired USB. In addition to optimizing the USB 3.0 specification for lower power consumption and higher protocol efficiency, USB 3.0 ports and cables enable backward compatibility and support for future fiber transmissions.
USB 3.0 will adopt a new physical layer in which the two channels are used to separate the data transmission and the acknowledgement process, thus achieving a higher speed. In order to replace the polling and broadcasting mechanisms used by USB, the new specification will use packet-routing technology and only allow the terminal device to transmit data when it is to be transmitted. The new link standard will also allow each component to support multiple data streams, and each data stream can maintain separate priority levels, which can be used to terminate jitter-causing interference during video transmission. The transport mechanism of the data stream also enables the inherent command queuing, which enables the data transmission of the hard disk to be optimized.
For backward compatibility with version 2.0, USB 3.0 features a 9-pin design with four pins and USB 2.0 in the same shape and definition, and the other five are specifically for USB 3.0.
The standard USB 3.0 male pin definition, the white part is the USB 2.0 connection dedicated pin, and the red part is dedicated to USB 3.0.
The pin definition of the standard USB 3.0 female port, the purple pin is dedicated for USB 2.0, and the red is dedicated for USB 3.0 connection.
If the USB 3.0 cable is not a Braid cable, there are a total of eight. It is worth noting that in the cable, the USB 2.0 and 3.0 power cables are shared.
Mini USB 3.0 interface is divided into A and B male ports (Plug), and the female interface (Receptacle) will have AB and B. From the shape point of view, the AB female port can be compatible with A and B male ports, 3.0 The pin of the male mouth is 9 stitches.
Few people will consider why a small USB interface standard will succeed. Is the transmission rate of USB the highest when it was born? Obviously not, but the USB interface is definitely the most powerful manpower - Microsoft and Intel and other industry leaders are favored by USB. The most direct example is that Intel has directly implemented the USB controller in its ICH South Bridge chip. ), and users in the world who use Intel and Microsoft products do not say that 100% is at least 60%, and the most important reason for the successful promotion of USB is this.
The IEEE 1394 interface introduced at the same time as USB is not so good. Although the theoretical transmission rate of IEEE 1394 is higher than that of USB (IEEE 1394 is the fastest serial bus at the current transmission rate), it lacks device manufacturers. The support is completely free of the popularity of USB.
We often see a situation where a motherboard often has up to six USB ports but no 1394 interface. Although the popularity of 1394 is extremely problematic, it is still the only transmission method in the field of imaging.
With the support of big companies such as Intel and Microsoft, USB is naturally flourishing and growing, but the rules of the IT industry are not going to fall, so USB has experienced technological innovation from 1.0 to 2.0 since the beginning of the 21st century. Now, the theoretical maximum transfer rate of USB 2.0 has reached more than 480Mbps (of course, it is difficult to achieve this data in practical applications), it seems that this data is very scary, but the computer's storage hardware is also constantly improving. Seeing the disk capacity calculated in terabytes and the Blu-ray video source in 10GB, we can't help but laughter - USB 2.0 is already stretched.
Fortunately, the term self-styled has become an industry taboo. The USB 3.0 standard was also introduced in 2008. The new USB 3.0 standard can provide more than 10 times more transmission rate than the previous USB 2.0, which is already the top level in the serial standard. It is.
The early USB version was generally not taken seriously when it was launched. The biggest reason is that the motherboard structure at that time was based on Baby-AT board. The USB function interface is an optional function on many motherboards. Some motherboard manufacturers provide 4X2 or 5X2 USB pins on the motherboard. Interfaces, and more to save costs, even the USB pin interface is saved. In addition, there is also a lack of support for BIOS firmware - at the time, many motherboards only provided a USB connection pin interface, and the motherboard's BIOS did not really support USB. In this way, in order to use USB, many users only need to upgrade the BIOS of the motherboard to refresh the BIOS of the motherboard to a BIOS that can support USB functions.
This situation continued until the birth of the ATX motherboard structure. However, the initial ATX motherboard is not very good at supporting USB. Because the ATX device connector is designed as a layer of height, the interface space that can be used is occupied by the traditional serial communication interface and LPT printer, there is no room left for the USB interface, so if you want to use USB For the interface, you must use a USB riser card to connect to the USB pin connector on the motherboard. However, the Back Panel of the ATX motherboard was designed as a second layer, and finally the USB interface has a foothold on the motherboard, no need to pass an external USB adapter card.
At the Intel Developer Forum in early 1999, participants introduced the USB 2.0 specification. In addition to the original Intel, Microsoft, and NEC members, the specification also includes three new members: HP, Lucent, and Philips. USB 2.0 is backward compatible with USB 1.1, with a transfer rate of 480Mbps, and supports broadband digital camera equipment and next-generation scanners, printers and storage devices
The introduction of USB technology may be the most important development of computer technology in modern times, because the emergence of USB has brought about a great revolution in the interface of the IT industry. Later, the impact is not only in the IT industry, but also in the consumer electronics industry. Therefore, the success of USB is unquestionable. In addition to 100% standard equipment in personal computers, laptops, and small notebooks, we can easily find USB traces on consumer electronics such as mobile phones, LCD TVs, printers, and photocopiers. I even read even Switzerland. There is a USB interface on the knife, which shows that USB is really ubiquitous. At this point, we have to admire the strong influence of Intel and Microsoft in the IT industry. Under the joint efforts of these two vendors, USB is hard to compare another interface-1394 to become the leading IT equipment and consumer electronics. The standard for communication interfaces.
Although USB currently has a high application range and Installation base (estimated from the introduction of USB 1.0 specification in 1996, there are 6 billion installation bases, and the number of 2 billion per year continues to grow), but when USB-IF planned USB specifications The technical blueprint of the USB interface has not been fully planned. It is not like the SATA-IO planning SATA technology development blueprint in 2001. The SATA is divided into 1.5 Gbps and 3.0 Gbps from the beginning. Three generations of 6.0 Gbps (please refer to the comparison table in Table 1), it feels like it is fighting and going; so since the introduction of the USB 2.0 specification in 2000, the USB 2.0 bandwidth has been greatly increased from 12Mb/s to 480Mb. /s, but we all know that the development law of the IT industry is that the bandwidth is never too much, and the storage capacity is never too much. So everyone thinks that USB 2.0 is no longer sufficient, so it has always been the main force of the company. USB 3.0 specifications, but these sounds are only for everyone's discussion. USB-IF has not officially responded to the USB 3.0 plan, until IDF, held in the United States on September 18, 2007, Pat Gelsinger explained USB The 3.0 plan, the development of USB 3.0 was confirmed.
When USB-IF planned USB technology in 1994, because it was positioned at a lower speed peripheral interface, the bandwidth was only set at 1.5Mb/s (Low Speed) and 12Mb/s (Full Speed); among them, Low Speed is mainly For Human Interface Devices (HID) such as keyboard, mouse, joystick, High Speed is mainly used for a large number of data transmission requirements, which is the specification of USB 1.0, and officially announced this specification in 1996. After the USB 1.0 related products were launched, with the increasing use of USB, the market also found problems with the USB 1.0 specification, so the specification of USB 1.1 was officially announced in 1998, and the problems found in version 1.0 were corrected. Most of them are about the USB Hub project.
Although the USB interface specification has been gradually completed since the release of the USB 1.1 specification, compared with IEEE 1394, the transmission performance is completely compared (see Table 2 for comparison), and because of this, the USB interface device is constantly After the ground is widely used, many devices, such as video conferencing CCD, or like nand flash flash drive (U disk), external hard disk, CD burner, scanner, card reader become a very popular USB interface. Applications. With the increasing acceptance of USB products by manufacturers and consumers in the market, it is hoped that the USB transmission performance will be better and louder. Therefore, in this context, USB-IF began to develop the USB 2.0 specification, and in 2000 officially announced the USB 2.0 specification. In the USB 2.0 specification, the most important thing is to increase the data transmission rate of 480 Mbps (also known as Hi-Speed). The USB specification has established three data transmission rates, and it has been maintained to date. The three rates are:
● 1.5Mbps (Low Speed)
● 12Mbps (Full Speed)
● 480Mbps (Hi-Speed)
As mentioned in the introduction, after the introduction of the USB 2.0 specification, it has temporarily solved the problem of bandwidth lag behind IEEE 1394, but with the wider application of USB, and the continuous improvement of other interface technologies, of course, more important. Yes - the capacity of the file is getting bigger and bigger, especially for audio and video data, so the environment of USB 2.0 is also more obvious. Among them, Nand Flash flash drive products, hard disk external box products and card readers (CardReader) products have the greatest impact. We briefly describe the following:
Although the USB 2.0 Hi-Speed data transfer rate is 480Mpbs, which is ideally 60MB/s, under the Windows based operating system, the actual performance is about 30MB/s to 35MB/s due to the limitation of the default driver. There is a long distance from 60MB/s. However, the performance of Nand flash is not good enough. It never used 30MB/s USB 2.0 bandwidth, so it is also safe; but with the continuous improvement of Nand flash technology, RAID 0 architecture (Data Stripping) introduced Nand flash product design, the bandwidth requirements of Nand flash products have surpassed the 30MB/s that USB 2.0 Hi-Speed can provide. For example, SSD (solid state disk) products based on SATA interface, the performance of sequential read exceeds 100MB/s, which shows the lack of USB 2.0 Hi-Speed performance. Therefore, whether it is a high-speed big thumb product (the mainland called U disk) or SSD, there is an urgent need for higher speed USB 3.0 to provide better performance. Although the SATA interface can meet the needs of SSD, USB has the advantage of providing bus power, which is where SATA or eSATA cannot match USB.
In addition to the Nand Flash flash drive product, the hard drive external box is also a small condition in which the outside water pipe is smaller than the water pipe inside. Since USB 2.0 Hi-Speed is only 30MB/s under Windows base OS, and the internal transfer rate of the hard disk is at least 60MB/s, the gap is quite large. In the past, when the file capacity was not too big, consumers were barely able to bear it, but all kinds of audio and video data were more than GB, and BD video data was more than 50 GB. If you still use USB 2.0 Hi-Speed to copy data, then really It will be maddening (please refer to Table 3). Therefore, with the annual growth rate of hard disk external box shipments maintaining more than 25% per year, it is imperative to provide a more efficient and universal interface.
The memory card, which is closely related to Nand Flash, also faces similar problems with nand flash; the previous memory card is not fast enough, but with the introduction of new memory card specifications, such as SDXC, up to 150MB/s The transfer rate, of course, is not what USB 2.0 Hi-Speed can satisfy, and USB 3.0 is a very important milestone for high-speed memory cards.
As with the pressure of the above product performance, the demand for USB 3.0 is getting higher and higher. Under the long-awaited call from all walks of life on September 18, 2007, Intel officially announced on the IDF that the specification of USB 3.0 will be launched in 2008, and also announced the main application range of USB 3.0 (please refer to Figure 1), formally responding Consumers have a need for faster transmission interfaces; Intel claims that USB 3.0 has the highest transmission performance of SuperSpeed, which is different from the traditional Low Speed, Full Speed and Hi-Speed. After a year, USB-IF finally announced the USB 3.0 specification on November 18, 2008, announcing the coming of another new era of USB.
● More than 10 times faster than the existing USB 2.0 Hi-Speed.
● Full consideration of backward compatibility issues, including the existing Class Driver can work on the new components.
● The same USB device model, which includes PIPE model, USB Framework and Transfer type.
● The efficiency of power management, in the new specification, provides better management of power performance, especially under the condition of Idle, and in order to replace the polling and broadcasting mechanisms used by USB. Provide better power management performance.
● The extension of architecture and technology. In order to increase the scalability of the technology, the planning of the communication protocol has considered the problem of efficient scale up and scale down.
Under the above premise, USB-IF adopts PCIe's main PHY architecture, with 5.0 Gbps as the data transfer rate of USB 3.0 SuperSpeed. In the choice of transmission coding technology, it is widely used in other high-speed serial transmission technologies. 8b/10b encoding technology to improve the recognition rate of transmission bits and reduce the electromagnetic interference of high frequency signals. In terms of backward compatibility, in order to coexist with USB 2.0 Low Speed, Full Speed and Hi-Speed, the design of the Dual-bus architecture is adopted (please refer to Figure 2). In the communication protocol, as mentioned above, the new specifications It uses a packet-routing technology and only allows the terminal device to transmit data when it is sent, instead of the polling and broadcasting mechanisms used by USB, which is also related to SATA Asynchronous notifications. The same is true. In terms of cable connector, USB 3.0 has added 5 contacts, two for data output, two data inputs, and a send list segment for data distribution. The new contacts will be placed side by side with 4 contacts. . The USB 3.0 bus power standard is 900mA and will support fiber optic transmission. This is the prototype of SuperSpeed technology.
● Must be able to support 5.0 Gbps data transmission
● Fully maintain compatibility with USB 2.0
● Control the form factor change of cable & connector to the minimum range
● EMI protection issues
● Maintain the tradition of easy USB use
Therefore, CableCon has set the CableCon specification for Stand A, Stand B, Micro B and Micro AB under such guidelines. USB-IF ingeniously imports USB3_TX+, USB3_TX-, USB3_RX+, USB3_RX- and GND into the new CableCon ( Please refer to Figure 3, 4, 5), and through the support of the Double-Stacked connector, USB 2.0 can coexist with USB 3.0.
However, I would like to remind you that Stand A is completely USB 2.0 and USB 3.0 connected to each other (this means you can plug the USB 2.0 Stand A Cable into the USB 3.0 Stand A connector, or you can plug the USB 3.0 standard cable into the USB 2.0. Stand A connector), but there is no way for Stand B and Micro B, but at least all the old cables can be plugged into the new interface, while the interfaces on the old devices cannot support the new cable (typical case, on the market). The connection ports of most known and unknown mobile phones are USB2.0 Micro-B. At least you can use the previous cable to access the 3.0 interface, but the new 3.0 cable cannot be supported.)
● Higher chip design barriers: High Speed Serial Link from 480 Mbps, 1.5 Gbps, 2.5 Gbps, 3.0 Gbps to 5 Gbps and 6 Gbps compared to pure digital IC designs, again and again testing IC design companies in simulation Designed with the ability to mix-mode. That's why only a handful of companies in Taiwan offer complete product and IP solutions from Serial ATA to PCI Express and USB 3.0.
● Consider the Design Margin problem for system vendors: For system vendors, using their own system products on an IC, the most worrying is that the design margin of the PCB layout is too small or the design rule is too complicated. Therefore, IC design companies must consider these design issues for system vendors and deepen the difficulty of high-speed IO chip design.
● IC mass production yield: Because high-speed IO has a physical layer (PHY) part design, the impact on IC yield is very important. Usually, the PHY is included in the SoC, which is often the killer with the highest yield. Therefore, how to maintain the mass production yield through the comprehensive consideration of the analog design design margin is a considerable challenge for IC design companies.
● IC mass production test method: usually more than 480MHz, often need to use more expensive test machine; but if the manufacturer can use the cheaper test machine to complete the high-speed IO related test, it is very important know how, for IC The cost is also very helpful.
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Post time: Jul-24-2018