1. USB UNIVERSAL SERIAL BUS

2. Typical Test Setup

3. USB Definition Universal Serial Bus. A standard bus type for all kinds of devices, including mice, scanners, digital cameras, printers, and others. Support 12 Mbps transfer rate. Hot swappable - devices can be connected and disconnected while computer is on.

4. USB DEVELOPMENT(1) Developed jointly by Compaq, Digital, IBM, Intel, Microsoft, NEC and Northern Telecom, the Universal Serial Bus (USB) standard offers a new standardised connector for attaching all the common I/O devices to a single port, simplifying today's multiplicity of ports and connectors. Traditionally, new peripheral devices were inserted in free ISA and PCI slots.

5. USB DEVELOPMENT(2) This can cause problems since the user is often responsible for setting switches and jumpers on the card and checking for conflicts with other cards. The user must open the case and insert the card then reboot the computer. Representatives from seven companies designed a better way to attach low-speed I/O devices to a computer. The resulting standard is called USB

6. GOALS of USB(1) The goals of the project were: No jumpers or switches to set User doesn’t have to open the case Only one kind of cable I/O devices get power from the cable Up to 127 devices attachable to a single computer Real-time device support Devices installable while the computer runs No reboot after installing a new device Inexpensive to manufacture

7. GOALS OF USB(2) USB meets these goals. The total USB 1.1 bandwidth is 1.5 MB/sec. A USB system consists of a root hub that plugs into the main bus. This hub has sockets for cables that attach to I/O devices. I/O devices also have sockets for additional devices. The topology of a USB system is a tree.

8. HUBS(1) Physical Topology is point-to-point tree.

9. HUBS(2) A USB device can be just a function, just a hub, or both a hub and a function. A USB device that contains an ENDPOINT (source/sink of data) is called a ‘function’ Root : Primary controller Hub: Allows the connection of multiple USB devices

10. HUBS(3) Data on the USB flows through a bi- directional pipe regulated by the host controller and by subsidiary hub controllers. An improved version of bus mastering allows portions of the total bus bandwidth to be permanently reserved for specific peripherals, a technique The USB interface contains two main modules: the Serial Interface Engine (SIE), responsible for the bus protocol, and the Root Hub, used to expand the number of USB ports.

11. HUBS(4) Powered hubs with at least 0.5 amps per port provide the most flexibility for future downstream devices. Port switching hubs isolate all ports from each other so that one shorted device will not bring down the others. The promise of USB was a PC with a single USB port onto which would be connected one large, powered device - like a monitor or a printer - which would act as a hub, linking up all the other smaller devices such as mouse, keyboard, modem, document scanner, digital camera and so on.

12. HUBS(5) The USB bus distributes 0.5 amps (500 milliamps) of power through each port. Thus, low-power devices that might normally require a separate AC adapter can be powered through the cable - USB lets the PC automatically sense the power that's required and deliver it to the device. Hubs may derive all power from the USB bus (bus powered), or they may be powered from their own AC adapter.

13. Physical Connection is Point to Point Physical connection is point to point.

14. USB ARCHITECTURE A widely used hardware interface for attaching peripheral devices. USB ports began to appear on PC ’ s in 1997, and Windows 98 was the first Windows to support it natively. Within a few years, USB became popular for connecting nearly every external peripheral device.

15. USB ARCHITECTURE Replacing the serial and parallel ports on a PC, at least four USB ports are standard on every computer. The USB system is composed of a USB host and USB devices.The devices category consist of hubs and nodes. Hubs are devices that provide additional connection points for other USB devices.

16. Types of USB The USB specification defines two types of plugs:series-A and series-B. Series-A connectors are used for devices in which the USB cable connection is permanently attached to devices at one end. Examples of these devices include keyboards, mice, and hubs.

17. Types of USB The series-B plugs and jacks are designed for devices that require detachable cabling(printers,scanners, and modems) Devices are plugged directly into a four-pin socket on the PC or hub using a rectangular Type A socket. All cables that are permanently attached to the device have a Type A plug. Devices that use a separate cable have a square Type B socket, and the cable that connects them has a Type A and Type B plug.

18. Conversely Both are four contact plugs and socets embedded in plastic connectors.the sockets can be implementde in vertical, right angle,and panel-mount veriations. The icon used to represent a USB connector depicts the centres of the A and B “plug connectors.”

19. Examples

22. USB 1.1 USB 1.1 uses with networking technologies such as Ethernet and TokeRing and provided more than enough bandwidth for the type of peripheral device is was designed to handle. It was also need for a soundcard.A lower communication rate of 1.5 Mbit/s.

23. USB 1.1 USB 1.1 overcame the speed limitations of UART-based serial ports, running at 12 Mbit/s USB also supports Plug-and-Play installation and hot plugging. A single USB port can be used to connect up to 127 peripheral devices. Starting in 1996, a few computer manufacturers started including USB support in their new machines. It wasn't until the release of the best-selling iMac in 1998 that USB became widespread. It is expected to completely replace serial and parallel ports.

24. Pentium Processor

25. Cpu and USB(1) USB achieves this by managing connected peripherals in a host controller mounted on the PC's motherboard or on a PCI add-in card. The host controller and subsidiary controllers in hubs manage USB peripherals, helping to reduce the load on the PC's CPU time and improving overall system performance. In turn, USB system software installed in the operating system manages the host controller.

26. Cpu and USB(2) Since many USB device drivers did not become available until after its release, this promise was never going to be realised before the availability of Windows 98. However, even post-Windows 98 its take-up was initially disappointing. There were a number of reasons for this. Some had complained that the USB architecture was too complex and that a consequence of having to support so many different types of peripheral was an unwieldy protocol stack.

27. USB 2.0 USB.0 specification was designed to compete with FireWire. Hewlett-Packard, Intel, Lucent, Microsoft, NEC and Philips jointly led the initiative to develop a higher data transfer rate than the 1.1 specification to meet the bandwidth demands of developing technologies. The USB 2.0 specification was released in April 2000. Bandwidth is 60 MB

28. USB 2.0 Also referred to as Hi-Speed USB, USB 2.0 is an external bus that supports data rates up to 480Mbps. USB 2.0 is an extension of USB 1.1. USB 2.0 is fully compatible with USB 1.1 and uses the same cables and connectors. "USB" being used to refer to the 12 Mbit/s and 1.5 Mbit/s speeds. At 480 Mbit/s, any danger that USB would be marginalised by the rival IEEE 1394 bus appear to have been banished forever.

29. USB 2.0 At the time of the February 1999 Intel Developer Forum (IDF) the projected performance hike was of the order of 10 to 20 times over existing USB 1.1 capabilities. However, by the end of the year the results of engineering studies and test silicon indicated that that was overly conservative, and by the time the USB 2.0 was released in the spring of 2000, its specified performance was a staggering 40 times that of its predecessor.

30. USB OTG Short for USB On-The-Go, an extension of the USB 2.0 specification for connecting peripheral devices to each other. USB OTG products can communicate with each other without the need to be connected to a PC. For example, a digital camera can connect to a PDA, or a mobile phone can connect to a printer or a scanner, as long as all the devices are USB OTG- compatible. USB OTG grew from the increasing need for portable devices to be able to communicate with each other as the culture of technology moves away from a PC-centric world. One of the important features of USB OTG is that the standard does not require a host PC in order for the devices to communicate. USB OTG devices, known as dual-role peripherals, can act as limited hosts or peripherals themselves depending on how the cables are connected to the devices, and they also can connect to a host PC.

31. Firewire

32. IEEE 1394a and b (FireWire) A very fast external bus standard that supports data transfer rates of up to 400Mbps (in 1394a) and 800Mbps (in 1394b). Products supporting the 1394 standard go under different names, depending on the company. Apple, which originally developed the technology, uses the trademarked name FireWire. Other companies use other names, such as i.link and Lynx, to describe their 1394 products. A single 1394 port can be used to connect up 63 external devices. In addition to its high speed, 1394 also supports isochronous data -- delivering data at a guaranteed rate. This makes it ideal for devices that need to transfer high levels of data in real-time, such as video devices. Although extremely fast and flexible, 1394 is also expensive. Like USB, 1394 supports both Plug-and-Play and hot plugging, and also provides power to peripheral devices.

33. Speed Comparison  Firewire 400 = IEEE 1394a  Firewire 800 = IEEE 1394b

34. Diffrencess and Similarities While USB 1.1's data rate of 12 Mbit/s, was sufficient for many PC peripherals, especially input devices, the higher bandwidth of USB 2.0 is for external peripherals as CD/DVD burners, scanners and hard drives as well as higher functionality peripherals of the future, such as high resolution video conferencing cameras. USB 2.0's increased bandwidth will also effectively increase number of devices that can be handled concurrently, up to its architectural limit.

35. Diffrencess and Similarities Existing USB peripherals will operate with no change in a USB 2.0 system. Devices, such as mice, keyboards and game pads, will not require the additional performance that USB 2.0 offers and will operate as USB 1.1 devices. Conversely, a Hi-Speed USB 2.0 peripheral plugged into a USB 1.1 system will perform at the USB 1.1 speeds.

36. Diffrencess and Similarities While Windows XP did not support USB 2.0 at the time of its release in 2001 - Microsoft citing the fact that there were no production quality compatible host controllers or USB 2.0 devices available in time as the reason for this - support had been made available to OEMs and system builders by early the following year and more widely via Windows Update and the Windows XP SP1 later in 2002.

37. Diffrencess and Similarities Since the USB 2.0 Specification encompasses all USB data transfer speeds - low (1.5MMbit/s), full (12Mbit/s) and high (480Mbit/s) - the USB Implementors Forum (USB-IF) sought to avoid confusion in the marketplace by introducing the terminology "Hi-Speed USB" to refer to the 480Mbit/s portion of the specification. However, despite the USB-IF's best efforts to ensure that vendors used the certified USB Logos appropriately, manufacturers were slow to switch to the new naming conventions and were often inconsistent in their use of it.

38. USB on MainBoard