Wireless USB

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USB Interface Description

Wireless USB removes any cable from the USB device. Wireless USB may be seen as WUSB. The Wireless USB specification defines the protocol, transaction types, bus management and programming interface. The Wireless USB standard does not define PHY and MAC layers, which are already provided for in the original USB standard, listed below. Like normal USB, Wireless USB connects USB devices with USB Hosts. Wireless USB hosts support up to 127 devices. Wireless data rates up to 480Mbps are supported

The Universal Serial Bus specification or wired USB defines the Mechanical, Electrical and Protocol layers of the interface. Cables and connectors are fully defined. USB defines 2 types of hardware, Hubs and Functions. Up to 127 devices may be connected together in a tiered Star topology. The limiting factor being 7 address bits. The physical wire segments are point-to-point between a Host, Hub, or Function. The system may only have one Host, which connects to a Hub. A USB Hub may connect to another Hub or to a USB Function. Each layer transition from Hub to Hub represents another Tier. USB Hubs allow connection to a USB bus, while USB Functions are the devices which perform some function. Wireless USB allows a USB device to transmit over RF, but has little to do with USB other than that.

The USB bus is a Bi-directional serial interface cable or card bus using Differential signal pairs. Differential NRZI data is transmitted Isochronous or Asynchronous between devices. Data is transferred at three different rates over a maximum cable length of 4 meters ~ over 4 wires, 2 of which carry data on a balanced twisted pair. Wireless USB add an additional RF connection.
USB may operate at any speed from 10kbps to 400Mbps in one of three speed modes. A Slow-Speed mode of 10kbps to 100kbps is used for devices such as a USB keyboard or USB mouse. Full-Speed mode is used by most devices and allows a transfer rate of 500kbps to 10Mbps. High-Speed mode [defined by USB 2.0] allows rates of up to 480Mbps, with a speed range of 25Mbps to 400Mbps. Transmission at the High-Speed mode requires the addition of 45 ohm termination resistors between each data line and ground. Operation at Full-Speed mode is 2.8 volts [High] to 0.3 volts [Low]. Operation at High-Speed mode is at 400mV +/-10% [High] to 0V +/- 10mV {Low]. Cable impedance for both modes is 90 ohms +/- 15% (differential).

Four different (packet) protocols are used; Control, Interrupt, Isochronous and Bulk. Each exchange contains 3 packets; A token packet which holds the address, a data packet which holds the data, and a handshake packet which terminate the exchange.
NRZI produces a change in the signal indicating a logic zero, no change indicates a logic one. Bit stuffing is used with NRZI to stop the signal remaining in the steady state condition; if more then 6 ones are transmitted (no change in the signal) a zero is inserted to produce a transition. NRZI, with bit stuffing is self clocking, allowing the receiver to synchronize with the transmitter.

USB Standard and Specifications

The Wireless Universal Serial Bus Specification Revision 1.0 was released 2005, with a supplement in 2006

The [wired version] Universal Serial Bus specification was first released in 1994.
The current wired USB standard, Revision 2.0 was released in 2000.

Wireless Host Controller Interface [WHCI]
The WHCI specification describes the register-level interface for a Host Controller for Wireless Universal Serial Bus (USB) Revision 1.0 [2006]

{Wireless USB Index}

USB Bus Interface IC Manufacturers

These are normal USB interface IC's, because the wireless function does not have much to do with the electrical USB interface.

USB IC Vendors;
Alcor Micro Corp. {USB Hub/Keyboard/Mouse/Flash Disk Controller ICs}

Atmel {USB Controllers Manufacturer}

Cypress {WirelessUSB modules, USB IC Manufacturer, USB 1.0/2/0, USB On-The-Go 'OTG'}

Fairchild Semiconductor, Corp. {Universal Serial Bus Transceiver, USB 2.0 FS Peripheral Transceiver, Dual Port Hi-Speed USB 2.0, USB Switch Dual SPDT Multiplexer/Demultiplexer}

Freescale Semiconductor, Inc. {USB Controller IC Manufacturer, Cable-Free USB}

FTDI Future Technology Devices International Limited {USB UART-Controller / USB Hub Controller}

Genesyslogic company {USB 2.0 Host Controller, USB 2.0 Flash Drive Controller, USB 2.0 Card Reader Controller}

initio Corp. {USB 2.0/1394a Bridge Controller; 400/800Mbit}

Intel {USB Controllers}

Kawasaki LSI {USB Controller IC Manufacturer}

Micrel Semiconductor {USB Transceiver, USB OTG Transceiver, USB Integrated Circuit Manufacturer, & USB Power Switches}

National Semiconductor {USB Controller IC}

NXP {UWB native device controller}

PLX Technology {USB Device Controller}

Standard Microsystems Corp. 'SMSC' {USB2.0 ATA/ATAPI Controller, Floppy Disk Controller, Flash Media Controller}

STMicroelectronics {USB Controller IC}

TI {USB IC Manufacturer, UWB}

Zilog {USB Controller ICs}

{Wireless USB Interface Index}

USB Pinout

The pin out table relates to the computer or device side. The wireless side has no pinout, it's wire-less.

The USB pinout is the same for either a type A or B connector, the difference is in the shape.

{Wireless USB Interface Index}

USB Connector Manufacturers

(Type A/B, Male/Female)

Four different types: the (A/B) Jacks are used on the chassis side, and the (A/B) Plugs are used on the cable ends. Type A jacks connect to type A plugs, and type B jacks connect to type B plugs. Normally Hubs will have an A jack. Cables will have an A plug on one end an a B plug on the opposite end. The connectors have both pins 1 and 4 longer then 3 and 4, so power and ground mate first. Having the power and ground pins mate first allow devices to be Hot-Swappable. Type A connectors point to the Hub, while type B connectors point to the Function. Normally a cable will have a type A connector on the computer side [Hub] and a USB type B connector on the far [function] side, to a USB device. The cable pin out and signal names are shown in the table below [90 ohms +/-15% differential impedance):

The main USB interface page provides a listing of connector manufacturers.

{Wireless USB Index}

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