Compound universal serial bus architecture providing precision synchronisation to an external timebase

Abstract

A method of synchronising a compound SuperSpeed USB device, comprising: providing data communication between a host computing device and the compound SuperSpeed USB device across the SuperSpeed USB communication channel; establishing a SuperSpeed USB communication channel to a SuperSpeed USB function of the compound USB device; establishing a non-SuperSpeed synchronisation channel to a non-SuperSpeed USB function of the compound USB device; and synchronising a local clock of the compound USB device to a periodic data structure within a data stream in the non-SuperSpeed synchronisation channel so that the local clock can enable synchronous operation of the compound USB device with one or more comparable USB devices.

1 . A method of providing a synchronisation channel to a SuperSpeed compliant USB device, the method comprising:
 providing a different unique device descriptor to each of a SuperSpeed function and a non-SuperSpeed function of the SuperSpeed compliant USB device; and   providing a Container ID for the SuperSpeed compliant USB device;   wherein the SuperSpeed and non-SuperSpeed functions are viewable as parts of a compound USB device by an operating system of a USB Host Controller, thereby enabling both said SuperSpeed function and non-SuperSpeed function to connect to said USB Host Controller simultaneously.   
     
     
         2 . A method as claimed in  claim 1 , further comprising:
 establishing a SuperSpeed communication channel to said SuperSpeed USB device;   establishing a non-SuperSpeed communication channel to said SuperSpeed USB device;   wherein said SuperSpeed communication channel and non-SuperSpeed communication channel are operable at the same time.