USB on the go (OTG) multi-hub endpoint reflector hub
A multi-host endpoint reflector enables a method of communication between multiple USB hosts through the USB devices connected to them, where data from one USB host is routed across the USB devices between endpoints of complimentary directions to one or more additional USB hosts. The multi-host endpoint reflector may be integrated with a USB hub controller to form a USB compound device to create a multi-host endpoint reflector hub. A USB multi-host endpoint reflector hub enables a USB OTG B device to become a host upon request by providing a data bridge between the OTG B device after it has transitioned to a host role while any other OTG A device that already is a host is not required to change its host role to a slave role. Therefore a plurality of OTG host devices may co-exist on the same interconnection system hub and communicate there between.
1. A method for (Universal Serial Bus) USB devices to communicate without restriction of being either a host or slave device, said method comprising the steps of:
powering on a USB hub controller, wherein the USB hub controller routes connectivity to a first USB host connected thereto;
enumerating a first USB OTG B device in device mode on a first downstream (DS) port with the first USB host;
issuing a command to the first USB OTG B device to become a second USB host;
inserting a endpoint reflector between the second USB host and a first internal device port of the USB hub controller; and
detecting a device disconnect on the first DS port, wherein the first USB host then sees a network control model (NCM) device connected thereto;
wherein:
the first and second USB hosts see a plurality of NCM devices, whereby non-control endpoints of the first and second USB hosts are mirrored, thereby enabling indirect communications between the first and second USB hosts;
the second USB host is reassigned as a USB host for the plurality of NCM devices.
2. The method according to claim 1 , further comprising the step of enumerating a second USB device on a second DS port with the first USB host.
3. The method according to claim 1 , wherein the step of inserting the endpoint reflector between the second USB host and the first internal device port of the USB hub controller comprises the step of using multiplexers to insert the bridge between the second USB host and the first internal device port of the USB hub controller.
4. A method for (Universal Serial Bus) USB devices to communicate without restriction of being either a host or slave device, said method comprising the steps of:
providing a first USB upstream (US) port;
providing a plurality of downstream (DS) ports; and
providing an internal USB network control model (NCM) endpoint reflector coupled to a first one of the plurality DS ports;
wherein:
the NCM endpoint reflector is inserted upon a command from a first USB host coupled to the first USB US port;
the plurality of DS ports are reflected to the first US port;
a plurality of USB hosts and a plurality of USB devices are coupled to the plurality of DS ports to provide simultaneous operation thereof; and
the first US port is reassigned as a USB host for the plurality of USB devices.
5. A (Universal Serial Bus) USB multi-host endpoint reflector hub, comprising:
an upstream (US) port adapted for coupling to a USB host;
hub controller logic coupled to a plurality of first downstream (DS) ports and to the US port;
a multi-host endpoint bridge coupled to the hub controller logic;
a first multiplexer coupled to the multi-host endpoint bridge;
at least one multiplexer coupled to the first multiplexer and the hub controller logic; and
at least one second downstream (DS) port adapted for coupling to at least one USB device or USB host.
6. The USB multi-host endpoint reflector hub according to claim 5 , wherein the USB host is a USB On-The-Go (OTG) device.
7. The USB multi-host endpoint reflector hub according to claim 5 , wherein the at least one USB device is a USB OTG device.
8. The USB multi-host endpoint reflector hub according to claim 5 , wherein the USB host is a USB On-The-Go (OTG) A device and the at least one USB device is a USB OTG B device.
9. The USB multi-host endpoint reflector hub according to claim 8 , wherein the OTG device A is an automobile display head unit.
10. The USB multi-host endpoint reflector hub according to claim 8 , wherein the OTG device B is a smart phone.
11. The USB multi-host endpoint reflector hub according to claim 5 , wherein the at least one USB device is a USB mass storage device.
12. The USB multi-host endpoint reflector hub according to claim 5 , wherein the host is an embedded host.
13. The USB multi-host endpoint reflector hub according to claim 5 , wherein the at least one USB device is a composite USB device containing multiple interfaces or endpoints of varying device classes, each being separately reflected.
14. The USB multi-host endpoint reflector hub according to claim 5 , wherein the USB device is a dual-role device.
15. The USB multi-host endpoint reflector hub according to claim 5 , wherein the endpoint reflector is programmable, adapted to emulate a plurality of USB endpoint types, and reflect each USB device class type between the hosts.
16. A (Universal Serial Bus) USB multi-host endpoint reflector hub, comprising:
a USB hub having a upstream (US) port and a plurality of first downstream (DS) ports;
a Communication Device Class (CDC) Network Control Model (NCM) endpoint reflector Media Access Control (MAC) address switch comprising:
a plurality of USB NCM devices, and
a first multiplexer coupled to the plurality of USB NCM devices;
a second plurality of multiplexers coupled to the plurality of USB NCM devices and the plurality of first DS ports of the USB hub; and
a plurality of second DS ports coupled to respective ones of the second plurality of multiplexers, and adapted for coupling to a plurality of USB host and slave devices;
wherein a second US port is reassigned as a USB host for the plurality of USB slave devices.
17. The USB multi-host endpoint reflector hub according to claim 16 , wherein the USB host is a USB On-The-Go (OTG) device.
18. The USB multi-host endpoint reflector hub according to claim 16 , wherein the USB slave device is a USB OTG device.
19. The USB multi-host endpoint reflector hub according to claim 16 , wherein the USB host is a USB On-The-Go (OTG) A device and the USB slave device is a USB OTG B device.
20. The USB multi-host endpoint reflector hub according to claim 19 , wherein the OTG device A is an automobile display head unit.
21. The USB multi-host endpoint reflector hub according to claim 19 , wherein the OTG device B is a smart phone.
22. The USB multi-host endpoint reflector hub according to claim 16 , wherein the USB slave device is a USB mass storage device.
23. The USB multi-host endpoint reflector hub according to claim 16 , wherein the host is an embedded host.
24. The USB multi-host endpoint reflector hub according to claim 16 , wherein the at least one USB device is a composite USB device containing multiple interfaces or endpoints of varying device classes, each being separately reflected.
25. The USB multi-host endpoint reflector hub according to claim 16 , wherein the USB device is a dual-role device.
26. The USB multi-host endpoint reflector according to claim 16 , wherein the endpoint reflector is programmable, adapted to emulate a plurality of USB endpoint types, and reflect each USB device class type between the hosts.
27. A (Universal Serial Bus) USB multi-host endpoint reflector hub, comprising:
a USB hub having an upstream (US) port and at least one downstream (DS) port;
a first multiplexer coupled to the US port and adapted for coupling to a first USB host;
a second multiplexer coupled to the at least one DS port and adapted for coupling to a second USB host or a USB dual role device, wherein a first command enables the USB hub to be switched in or out based upon a second command or the first command that changes the dual role device to its second host role;
a multi-host endpoint reflector coupled between the first and second multiplexers; and
control logic coupled to and controlling the first and second multiplexers, and the multi-host endpoint reflector;
wherein:
the multi-host endpoint reflector is adapted to reflect endpoints directly to the first host; and
the second USB host is reassigned as a USB host for a plurality of second DS ports.
28. The USB multi-host endpoint reflector hub according to claim 27 , wherein connectivity between the first and second hosts is selected from the group consisting of USB host-to-device, USB device-to-device and USB device-to-host connectivity.
29. The USB multi-host endpoint reflector hub according to claim 27 , wherein the at least one DS port reverts to at least one charging port when the USB hub is bypassed and is no longer connected to a USB host.