2 Interface USB 3.0 SuperSpeed
2.1 Introduction

USB interface is a serial bus interface type. Its key benefits include in particular:

  • Low price
  • Relatively high transfer rate (depends on the particular specification)
  • Full support of audio and video data transfers realized in real time,
  • Dynamic scalability (support of Plug&Play, i. e. without rebooting and driver installation)
  • And transfer of power supply on bus (DC 5 V, consumption up to 100 mA (max. 500 mA)).

All devices connected to the USB interface share among themselves the entire bandwidth. USB bus is then controlled by one central facility (Host Root HUB), which coordinates transmission and reception of data, respectively cooperation of other USB devices. The path between the control (central) USB device, and any other USB device can contain in maximum five hubs. The maximum cable length between two USB devices is limited to 5 meters.

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Classic USB bus topology

Connected USB devices are on the bus clearly identified by the USB address that is assigned immediately after connecting the USB device to the interface. It is possible to connect on the USB interface up to 127 devices.

The speed modes of data transfer

  • Super Speed Mode – transfer rate up to 4,8 Gbit/s, specification USB 3.0
  • High Speed Mode – transfer rate up to 480 Mbit/s, specification USB 2.0
  • Full Speed Mode – transfer rate up to 12 Mbit/s, specification USB 1.1
  • Low Speed Mode – transfer rate up to 1,5 Mbit/s, specification USB 1.1

The individual types of USB devices