This book is for developers who are involved with designing or programming devices that use the Universal Serial Bus (USB) interface. If you are a hardware designer, if you write firmware that resides inside USB devices, or if you write applications that communicate with devices, this book is for you. The USB interface is versatile enough to serve just about any device function. Familiar USB peripherals include mice, keyboards, drives, printers, speakers, and cameras. USB is also suitable for data-acquisition units, control systems, and other devices with specialized functions, including one-of-a-kind designs. The right choices of device hardware, software drivers and development tools and techniques can help you design devices that perform their functions without errors or user aggravation. This book will guide you along the way.