USB tutorials & labs.

The most complete USB curriculum on the internet — starting from the peripheral-connectivity problem USB was created to solve, through the host-centric architecture, physical layer, generations and speed modes, enumeration, descriptors, device states, endpoints, the four transfer types, packets, the transaction model, scheduling, hubs, power management, USB 3.x SuperSpeed dual-bus architecture, device-controller RTL, host-controller (EHCI / xHCI) overview, verification, debugging, SoC integration, interview mastery, real-industry case studies, and design-review checklists.