https://www.beyondlogic.org/usbnutshell/usb1.shtml
USB in a NutShell - Chapter 1 - Introduction
Introduces the Universal Serial Bus covering the various chapters of the spec and what is required to be read.
usb in a nutshellchapterintroduction
https://www.beyondlogic.org/usbnutshell/usb5.shtml
USB in a NutShell - Chapter 5 - USB Descriptors
Details the USB descriptors including the Device, Configuration, Interface, Endpoint and String Descriptors
usb in a nutshellchapterdescriptors