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For developers of USB devices, firmware, hosts, and host software.
Other useful pages
Debugging Non-functioning USB Ports. The ongoing tale of my new PC and its USB ports.
My article Debugging USB Firmware is online at Circuit Cellar.
USB Embedded Hosts: The Developer's Guide is available. Details.
The USB-IF is the non-profit organization that sponsors the USB specifications and provides support for developers.
The USB-IF Developers Discussion Forum no longer exists. An alternative is my PORTS forum.
USB 3.1 vs USB 3.0: Technical Comparison. From Aditya Mittal and Rahul Kumar at Arrow Devices.
SuperSpeed Extends USB (short introduction to SuperSpeed)
The USB 2.0 specification supports bus speeds of 480 Mbps (high speed, also called Hi Speed), 12 Mbps (full speed), and 1.5 Mbps (low speed). Note that USB 2.0 does not mean "high speed." A USB 2.0 device can be any speed.
As of May, 2007, the Mini-A and Mini-AB connectors have been deprecated in favor of the Micro-A and Micro-AB.
An ECN to the USB 2.0 specification adds a new descriptor type for composite devices: the interface association descriptor (IAD).
My article Inside USB 2.0: What the New Spec Means for Developers (EDN).
OHCI (OpenHCI) -- Open Host Controller Interface Specification for USB (Low and full speed)
Universal Host Controller Interface (UHCI) Design Guide (Low and full speed)
OpenCores is developing a USB 2.0-compliant Verilog/VHDL function core.
The ULPI (UTMI + Low Pin Interface) specification describes an interface that reduces the pin count for discrete USB transceiver implementations.
The USB Power Delivery (PD) specification defines hardware and protocols that allow bus currents as high as 5A, VBUS voltages up to 20V, more precise power management, and even the ability to reverse the flow of current so a device can provide power to a host.
PoweredUSB enables USB devices to draw more than 500mA from the cable. Targeted at point-of-sale (POS) applications. Requires a license from IBM.
Options for wireless USB communications.
Media Agnostic USB
The USB-IF's Media Agnostic (MA) USB specification enables using USB drivers to communicate over a variety of wireless and wired interfaces.
The first use for MA USB will be 1-Gbps wireless communications based on the WiGig Serial Extension (WSE) v1.2 specification from the Wi-Fi Alliance. The Wi-Fi Alliance transferred the WSE specification to the USB-IF for use in MA USB. WiGig uses unlicensed 60-GHz frequencies for short-range communications.
Wireless USB (formerly Certified Wireless USB)
The USB-IF's Wireless USB Promoter Group has developed a wireless USB (WUSB) specification for communicating at up to 480 Mbps.
Challenges of Migrating to Wireless USB. From Ellisys.
Wireless USB FAQ. From Everything USB.
Wireless USB Blog. From Karsten Stopp.
Cypress's WirelessUSB system uses a 2.4-Ghz wireless connection and enables implementing wireless devices that function as low-speed USB devices.
Articles, books, classes, and more.
USB Made Simple. A series of articles from MQP Electronics.
Jack Ganssle's An Introduction to USB Development from Embedded Systems Programming.
Stealing USB Port Power. How to design bus-powered devices. Robert Kollman and John Betten, EDN.
USB 3.0 Technology: Comprehensive Guide to SuperSpeed USB. The USB 3.0 specification in depth. Ebook version.
USB: The Universal Serial Bus. Low-level programming of host controllers.
Universal Serial Bus System Architecture, Second Edition. Inside the USB 2.0 specification.
Developing Drivers with the Windows Driver Foundation. Windows drivers for devices that can't use an existing driver.
USB System Architecture Class. From Mindshare.
Information on finding USB products and getting them to work.
USBStuff has USB products from many vendors.
B & B Electronics has a good selection of USB converters, cables, and hubs.
USConverters has many USB converters.
Help in getting peripherals working
The USB Implementers Forum has an FAQ that answers many user questions.
EverythingUSB has links to drivers, other news and reviews, and a product finder.
General USB Troubleshooting in Windows 98, Windows 98 Second Edition, and Windows Me. From Microsoft. Article ID: 263218.
Unable to Print from Command Prompt or MS-DOS Program with USB Printer From Microsoft. Article ID 259939.