Universal Serial Bus USB is an industry standard that establishes features for cables and connectors and maintains protocols for connection, communication, and power supply (interfacing) between computers, devices, and other computers. USB-C Various types of the most recent USB hardware exist.
History
USB was developed in 1999 by a group of seven companies. Compaq, DEC, IBM, Microsoft, Intel, NEC, and Nortel. It was developed to make it easier to connect an external device to a PC. USB devices can be used on multiple platforms like Windows, Mac, and Linux.
How to connect a USB device to a computer.
Connecting a USB device to a computer is very easy. Just insert the USB device into the computer's USB port and it will detect the device and start working. This does not prompt you to reboot your computer. Universal Serial Bus Drive is the most commonly used USB device.
There are three basic sizes of USB connectors:
Certified size
Mini size
Micro size
Types of USB versions
- USB 1.1
- USB 2.0 and 3.0
- USB 3.1
USB 1.1
Released on January 1, 1996, USB 1.0 specified specific data rates of 1.5 Mbt/s (low bandwidth or low speed) and 12 Mbt/s speed. Extension cables or pass-through monitors were not allowed due to time and power constraints. Some USB devices entered the market until the release of USB 1.1 on August 1, 1998. USB 1.1 was the earliest version that was widely accepted and was designated by Microsoft as a " "legacy-free PC".
USB 2.0 and 3.0
USB 2.0 was released in April 2000, with the addition of high speed or high bandwidth called 480 Mbps (60 MB / s) in addition to the USB 1.x full speed signaling rate of 12 Mbps.
An explanation of USB specific 3.0 was released on November 12, 2008, which was transferred from the management of the USB 3.0 promoter group to the USB Implementers Forum (USB-IF) and announced at the Superspeed USB Developers Conference on November 17, 2008.
In addition to the three existing transfer modes, the superspeed bus offers a nominal transfer mode of 5.0 Gbit / s. Its functionality depends on a number of factors, including physical symbol encoding and link-level overhead. With 8b / 10b encoding at 5 Gbit / s signaling rate, 10 bits are required to transmit each byte, so the raw throughput is 500 MB / s. When it comes to flow control, packet framing, and protocol overhead, transmitting in an application of 400 MB / s (3.2 Gbit / s) or higher is realistic. Communication in superspeed transfer mode is full-duplex; The earlier modes are semi-dual, arbitrated by the host
USB 3.1
Released in July 2013, USB 3.1 has two variants. The first one saves USB 3.0's superspeed transfer mode and is labeled USB 3.1, and the second version introduces the new USB 3.1 superspeed + transfer mode. Superspeed + doubles the maximum data signaling Encoding scheme changed to 128B / 132B and reduced line encoding overhead by only 3% while 10GBT / s rate.
USB 3.0 also introduced the UASP protocol, which generally provides faster transfer speeds than the BOT (bulk-only-transfer) protocol.
USB mass storage / USB drive
USB mass storage device class (MSC or UMS) standardizes the connection on the storage device. First, for the purpose of magnetic and optical drives, flash drives were extended to support. It has also been expanded to support a variety of novel devices, as many systems can be controlled by the familiar metaphor of file manipulation in directories. The process of making a novel device look like a familiar device is also known as extension. The ability to boot a right-locked SD card with a USB adapter is especially beneficial for maintaining the integrity of the booting medium and the original status, without wastage.
Electrical specification Of USB
The USB signal is transmitted using differential signaling on a twist-pair data cable with a 90 ± ± 15% characteristic interruption.
- Low-speed (LS) and full-speed (FS) modes use single data pairs with half-double D + and D-labeled. The transmitted signal level is 0.0-0.0 V for the logical low and 2.8–3.6 V for the logical high level. The signal lines are not terminated.
- High-speed (HS) mode uses the same wire pair, but with different electrical conventions. Minimum −10 to 10 mV for logical high level and too low signal voltage and to a logical high level. It ends at a 40 ० 450 mV and 45 ground or 90 Ω difference to match the data cable barrier.
- Superspeed (SS) will add two additional pairs of shielded twisted wires (and new, mostly compatible extended connectors). These are dedicated to full-duplex superspeed operation. The superspeed link works independently from the USB 2.0 channel and prioritizes the connection. The link configuration is done using LFPS (low-frequency periodic signaling, approximately 20 MHz frequency), and the voltage d-thrust on the side of the transmitter in the electrical characteristics and the adapter linear parallel on the receiver side to cope with the electrical loss in the transmission line and thus the link. Introduction to the link training concept.
- Superspeed + (SS +) uses increased data rates (Gen 2 × 1 mode) and / or additional lanes in the USB-C connector (Gen 1 × 2 and Gen 2 × 2 modes).
The USB connection is always between the host or hub at the end of the A connector and the "upstream" part of the device or hub on the other end.
0 Comments