In reality, a USB data pipe is a connection from the host controller to a logical entity within a device, i. Because pipes correspond to endpoints, the terms are sometimes used interchangeably.
The host then uses the concept of a data pipe to ensure the data to and from a device is correctly directed or the source is known. The data pipe uses a combination of the address, endpoint and also the direction to define it. To communicate with the zero endpoints a special form of data pipe is needed because it needs to be used to establish the initial communication. It is called the Default Control Pipe and it can be used when the initial physical connection is made.
For USB 1 and 2 a four wire system is employed. As detailed elsewhere, the cables carry: power, ground and then there is a twisted pair for the differential data transfer. For USB 3, new lines were introduced. The use of twisted pairs and differential signalling reduces the effects of external interference that may picked up. It also reduces the effect of any hum loops, etc that could cause issues.
As it is not related to ground, but the difference between the two lines, the effects of hum are significantly reduced. The data uses an NRZI system, i. In terms of operation, when the USB host powers up, it polls each of the slave devices in turn. The USB host has address 0, and then assigns addresses to each device as well as discovering the slave device capabilities in a process called enumeration.
Transactions between the host and device comprise a number of packets. As there are several different types of data that can be sent, a token indicating the type is required, and sometimes an acknowledgement is also returned. Each packet that is sent is preceded by a sync field and followed by an end of packet marker.
This defines the start and end of the packet and also enables the receiving node to synchronise properly so that the various date elements fall into place. The data transfer methodology and protocol for USB provides an effective method of transferring the data across the interface in an effective and reliable manner. Within the USB system, there are four different types of data packets each used for different types of data transfer.
Handshake Packets: The handshake packets are used acknowledging data packets received or for reporting errors, etc. Start of Frame Packets: The Start of Frame packets used to indicate the start of a new frame of data. There are many USB connectors and leads available, and these leads now have many more wires for higher rate data transfer. Accordingly the data transfer speeds have increased many fold over the first USB specification that was released and the devices that were available.
The web interface allows users to configure the DT80, access logged data and see current measurements as mimics or in a list using a web browser. The software loads in your web browser so there is no need to install cumbersome applications on your computer. The configuration editor allows you to view, edit and save logger configurations in an easy-to-use Windows Explorer style user interface.
The configuration tree view allows definition of measurement schedules and measurements. Wiring diagrams show available wiring configurations for each sensor type. Configuration can be stored and retrieved on either the logger or a local computer. Mimics are organized into panels which can be modified to highlight custom alarm conditions or data grouping. Mimics include dials, bar graphs, thermometers, etc. The major feature is what is termed the SuperSpeed bus, which provides a fourth transfer mode which gives data transfer rates of 4.
The standard is also backwards compatible with USB 2. Often USB ports on computers, etc. SS USB. Super Speed USB. The use of USB 3. This enables users to charge much larger devices including laptop computers, etc.
All these advances mean that when compared to previous releases, USB 3. This was released in September It retains the existing USB 3. The increase in bandwidth is a result of multi-lane operation over existing wires that were intended for flip-flop capabilities of the USB-C connector. Another key aspect of USB 3. The new standard provides more flexibility and functionality. It is based around the Thunderbolt 3 protocol specification and as such it supports data throughput up to 40 Gbps.
It is compatible with Thunderbolt 3, and also backwards compatible with USB 3.
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