USB is "Universal Serial Bus", the Chinese name is Universal Serial Bus. A way that electronic products can be connected to each other. Used in mobile, audio-visual, automotive electronics, multimedia, electrical appliances, etc. At present, it has been widely used in various external devices. There are three types of USB interfaces: USB1.1 and USB2.0, and usb3.0. In theory, the transmission speed of USB1.1 can reach 12Mbps/sec, while USB2.0 can reach the speed of 480Mbps/sec, and it can be backward compatible with USB1.1. The transfer rate of USB3.0 is about 3.2Gbps (ie 320MB/S). The theoretical maximum rate is 5.0Gbps (ie 500MB/S).
With the rapid development of computer hardware and the increasing number of peripheral devices, keyboards, mice, modems, printers, and scanners have long been known to everyone. Digital cameras, MP3 players, and so many devices, USB It is based on this purpose.
History of USB Link Application Development
USB is an interface that standardizes and simplifies the connection of computer peripheral devices. Machine Company), Microsoft (Microsoft), Northern Telecom (Northern Telecom) jointly developed.
Another significant advantage of USB is that it supports hot-plugging, which means that you can safely connect or disconnect USB devices when the device is turned on, achieving true plug-and-play.
In the 1910s, although USB devices have been widely used, the more common one is the USB2.0 interface, whose transmission speed is 480Mbps.
USB2.0 is compatible with USB1.1, which means that USB1.1 devices can be used in common with USB2.0 devices, but at this time, USB2.0 devices can only work at full speed (12Mbit/s). USB2.0 has three working speeds: high-speed, full-speed and low-speed. High-speed is 480Mbit/s, full-speed is 12Mbit/s, and low-speed is 1.5Mbit/s. Among them, full speed and low speed are designed to be compatible with early devices that can only work in USB1.1 or USB1.0. The USB bus is a one-way bus, the main controller is on the PC, and the USB device cannot actively communicate with the PC. In order to solve the problem of mutual communication between USB devices, the relevant manufacturers have developed the USB OTG standard, which allows embedded systems to communicate with each other through the USB interface, thus eliminating the need for PC.
In the 2010s, the new USB2.0 specification renamed the USB standard and changed the original USB 1.1 to USB 1.1 Full Speed (full-speed version), and at the same time changed the original USB 2.0 to USB 2.0 High-Speed ( high-speed version).USB 3.0 is the latest USB specification in the 2010s, initiated by big companies like Intel.
USB 3.0 - also known as SuperSpeed USB - provides a standard interface for a variety of devices that interface with PCs or audio/high frequency equipment. Devices from keyboards to high-throughput disk drives can use this low-cost interface for a smooth-running plug-and-play connection with minimal user effort. The new USB 3.0 provides the following enhancements while maintaining compatibility with USB 2.0:
1. Greatly improve the transmission bandwidth - theoretically up to 5Gbps full-duplex (USB2.0 theoretically up to 480Mbps half-duplex)
2. Better power management is achieved
3. Enables the host to provide more power to the device, enabling applications such as USB-rechargeable batteries, LED lighting, and mini fans.
4. Enables the host to identify the device faster
5. New protocols make data processing more efficient
For system and ASIC developers, the broad availability of USB 3.0 chips and IP ensures that every design requirement can be met in a timely manner. This comprehensive support is especially important for standards like USB 3.0, where speed, advanced protocols, and various cable lengths (from inches to meters) make design and standards compliance a challenge.