About This Note

This document provides a high-level introduction to the features of the Universal Serial Bus (USB). It also describes the Apple Macintosh software components and programming interfaces that support USB device hardware.

This document is intended for experienced hardware and software developers interested in creating USB device drivers for the Macintosh platform. Hardware and software developers reading this document should be familiar with the information in the PCI Driver Development Kit, available on the Developer CD Series, and have a copy of the current Universal Serial Bus Specification, which can be found at http://www.usb.org/developers.

If you are not familiar with the terminology used to describe the elements that make up the USB architecture, see USB Terminology before moving on to the rest of the material in this document.

If you are interested in finding about about the features USB provides and want to get a basic desription of the elements that make up the USB topology, you should read the introductory material in Overview and USB Topology and Communication .

If you already understand the features and topology of the USB architecture and want to get to work developing a Mac OS compatible device driver for your USB device, see the material in USB Software Components and the reference material in USB Services Library Reference and USB Manager Reference In addition, look at the example code provided in the Mac OS USB Device Driver Kit.

Every attempt is made at keeping the information in this document concurrent with the latest revision of the Mac OS USB software. Major differences between versions of the software are noted in Changes In Mac OS USB Version 1.1 . In particular, this draft includes information related to changes between version 1.0/1.0.1 and version 1.1 of the Mac OS USB software.

Contents of This Note

The information is arranged in four chapters and three Appendices:

• Overview provides an introduction to the USB architecture.
• USB Topology and Communication provides a high level overview of the topology of the USB and how the host software communicates with devices over the USB.
• USB Software Components is an overview of the components that make up the Macintosh USB software architecture.
• USB Services Library Reference describes the Mac OS USB system software libraries that developers use to support programming USB class drivers for their USB devices.
• USB Manager Reference describes the Mac OS USB Manager library that provides service to the Mac OS and extension clients.
• Changes In Mac OS USB Version 1.1 provides information about the differences that developers need to be aware of in version 1.1 of the Mac OS USB software.
• Conventions and Abbreviations provides a list of standard abbreviations used in Apple technical documentation.
• USB Terminology defines many of the terms that are commonly used in discussion related to the USB hardware and software architecture.