Patent ID: 7131035

Claim:
A USB (Universal Serial Bus) host controller for handling data traffic between at least one USB device and a computer system, the USB host controller having a register set comprising: at least one host controller capability register configured to store data indicative of operational capabilities of the USB host controller; and at least one host controller operational register configured to store data for controlling the operation of the USB host controller, wherein said at least one host controller capability register is configured to store data indicative of available diagnostic modes that the USB host controller can enter, wherein said at least one host controller operational register is configured to store diagnosis data for controlling the operation of the USB host controller in diagnostic modes, and wherein said at least one host controller capability register is configured to store a single step mode flag indicating that one of said available diagnostic modes of the USB host controller is a single step mode in which the USB host controller is forced to process a single transaction at a time.