usb interface means Universal Serial Bus, a serial bus standard. USB is the abbreviation of "Universal Serial Bus"; USB is also a technical specification for input and output interfaces, which is widely used in personal applications. Information and communication products such as computers and mobile devices standardize the connection and communication between computers and external devices.
The operating environment of this tutorial: Windows 10 system, DELL G3 computer.
Universal Serial Bus is a serial bus standard
Universal Serial Bus (English: Universal Serial Bus, Abbreviation: USB) is a serial bus standard and a technical specification for input and output interfaces. It is widely used in information and communication products such as personal computers and mobile devices, and has been extended to photographic equipment, digital TVs (set-top boxes), and game consoles. and other related fields. The latest generation is USB4, with a transmission speed of 40Gbit/s, a three-stage voltage of 5V/12V/20V, and a maximum power supply of 100W. The new Type C interface allows blind plugging of the front and back.
USB is an external bus standard that regulates the connection and communication between computers and external devices. The USB interface has hot-swappable function. The USB interface can connect a variety of peripherals, such as mice and keyboards. USB was jointly launched in 1996 by Intel and other companies at the end of 1994. It has successfully replaced the serial port and parallel port and has become a must-have interface for today's computers and a large number of smart devices. The USB version has experienced years of development and has now developed into the USB4 version. For most engineers, the main obstacles in developing USB2.0 interface products are: facing the complex USB2.0 protocol, writing their own USB device drivers, and being familiar with microcontroller programming. This not only requires considerable VC programming experience, but also the ability to write USB interface hardware (firmware) programs. So most people gave up developing USB products themselves.
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USB 1.0
USB 1.0 appeared in 1996, with a speed of only 1.5Mb/s (bits per second); it was upgraded to USB 1.1 in 1998, and the speed was greatly increased to 12Mb/s. This standard interface can still be seen on some old devices . USB1.1 is a more common USB specification. The transmission rate in high-speed mode is 12Mbps, and the transmission rate in low-speed mode is 1.5Mbps (b means Bit). b/s generally represents the bit transmission speed, and bps represents the bit transmission rate. Numerically equal. B/s and b/s, BPS (bytes per second) and bps (bits per second) cannot be confused. 1MB/s (megabytes/second) = 8Mbps (megabits/second), 12Mbps = 1.5MB/s, most MP3 are this type of interface. [2] As shown in Figure 1.
USB 2.0
The USB2.0 specification evolved from the USB1.1 specification. Its transmission rate reaches 480Mbps, which is 60MB/s converted into MB, which is enough to meet the rate requirements of most peripherals. The Enhanced Host Controller Interface (EHCI) in USB 2.0 defines an architecture that is compatible with USB 1.1. It can drive USB 1.1 devices with USB 2.0 drivers. In other words, all devices that support USB 1.1 can be used directly on the USB 2.0 interface without worrying about compatibility issues, and accessories such as USB cables, plugs, etc. can also be used directly.
The change brought about by using USB for printer applications is a substantial increase in speed. The USB interface provides a connection speed of 12Mbps, which is more than 10 times faster than the parallel port. Printing files can be transferred at this speed. Time is greatly reduced. The USB 2.0 standard further increases the interface speed to 480Mbps, which is 20 times the speed of ordinary USB, significantly reducing the transmission time of printing files.
USB 3.0
The USB 3.0 Promoter Group, composed of industry giants such as Intel, Microsoft, HP, Texas Instruments, NEC, ST-NXP and other industry giants, announced that the organization is responsible for formulating The new generation USB 3.0 standard has been officially completed and publicly released. The theoretical speed of USB 3.0 is 5.0Gb/s, but in fact it can only reach 50% of the theoretical value, which is close to 10 times that of USB 2.0. The physical layer of USB3.0 uses 8b/10b encoding, so the theoretical speed calculated is only 4Gb/s. The actual speed will also deduct the protocol overhead, which is less than 4Gb/s. Can be widely used in PC peripherals and consumer electronics.
USB 3.0 will be called "USB SuperSpeed" in actual device applications, complying with the previous USB 1.1 FullSpeed and USB 2.0 HighSpeed. It is expected that commercial controllers supporting the new specification will be available in the second half of 2009, and consumer products are already on the market.
USB 3.1
USB 3.1 Gen2 is the latest USB specification initiated by Intel and other companies. The data transmission speed can be increased to 10Gbps. Compared with USB 3.0 (i.e. USB 3.1 Gen1) technology, the new USB technology uses a more efficient data encoding system and provides more than double the effective data throughput rate. It is fully backwards compatible with existing USB connectors and cables.
USB 3.1 Gen2 is compatible with existing USB 3.0 (i.e. USB 3.1 Gen1) software stack and device protocols, 5Gbps hubs and devices, and USB 2.0 products.
USB-IF's latest USB naming specification, the original USB 3.0 and USB 3.1 will no longer be named, all USB standards will be called USB 3.2, taking into account compatibility, USB 3.0 to USB 3.2 are called respectively USB 3.2 Gen 1, USB 3.2 Gen 2, USB 3.2 Gen 2x2.
USB 4.0
The USB4.0 specification was published by the USB Implementers Forum on August 29, 2019. USB4 is based on the Thunderbolt 3 protocol. It supports 40 Gbit/s throughput, is Thunderbolt 3 compatible, and is backwards compatible with USB 3.2 and USB 2.0.
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