This free online book “USB in a NutShell: Making sense of the USB standard”. Starting out new with USB can be quite daunting. With the USB 2.0 specification at 650 pages one could easily be put off just by the sheer size of the standard.
This is only the beginning of a long list of associated standards for USB. There are USB Class Standards such as the HID Class Specification which details the common operation of devices (keyboards, mice etc) falling under the HID (Human Interface Devices) Class – only another 97 pages. If you are designing a USB Host, then you have three Host Controller Interface Standards to choose from. None of these are detailed in the USB 2.0 Spec.
The good news is you don’t even need to bother reading the entire USB standard. Some chapters were churned out by marketing, others aimed at the lower link layer normally taken care off by your USB controller IC and a couple aimed at host and hub developers. Lets take a little journey through the various chapters of the USB 2.0 specification and briefly introduce the key points.
Table of Contents
- Architectural Overview
- USB Data Flow Model
- USB’s Two Standard Connectors
- Low Level Electrical Signalling
- Protocol Layer
- USB Device Frame Work
- USB Host Hardware and Software
- Hub Specification
Link: Read online.