Flexible mobile device connectivity to automotive systems with USB hubs
A method to enable a vehicle's embedded USB Host system to connect to multiple mobile devices through a USB Hub, regardless of whether the mobile devices are configured to function as USB Hosts or USB Devices, without USB On the Go (OTG) controllers or additional vehicle wiring or inhibiting the functionality of any consumer devices connected to the same USB Hub. Preferably, the method is configured to provide no additional cabling or hardware changes to accommodate this capability. The method can be employed between a vehicle's embedded USB Host, USB Hub and at least one consumer accessible USB port. When the consumer device is acting as a USB Host, signals between the consumer device and the vehicle's embedded USB Host are processed through a USB bridge, thereby rendering the consumer device compatible with the vehicle's embedded USB Host.
1 . An integrated circuit, comprising:
an upstream universal serial bus (USB) port configured to be connected to a first USB host;
a downstream USB port configured to be connected to a USB consumer device;
a USB routing logic circuit; and
a bridge device comprising a bridge controller, a first USB device having a first control endpoint, a first input buffer, and a first output buffer, and a second USB device having a second control endpoint, a second input buffer, and a second output buffer,
the bridge controller configured to:
receive a first descriptor request directed to the first control endpoint from the first USB host connected to the upstream USB port,
transmit the first descriptor request to the first USB device and receive a first descriptor response generated by the first USB device in response to the first descriptor request,
encapsulate the first descriptor response to include information identifying the first USB host,
transmit the encapsulated first descriptor response back to the first USB host,
receive a second descriptor request directed to the second control endpoint from the USB consumer device acting as a second USB host connected to the downstream USB port;
transmit the second descriptor request to the second USB device and receive a second descriptor response generated by the second USB device in response to the second descriptor request,
encapsulate the second descriptor response to include information identifying the USB consumer device as the second USB host, and
transmit the encapsulated second descriptor response back to the USB consumer device,
the USB routing logic circuit configured to bypass the bridge device when the USB consumer device is functioning as a USB device rather than the second USB host.
2 . The integrated circuit of claim 1 , wherein the bridge controller is further configured to associate the first descriptor response with the first output buffer and to associate the second descriptor response with the second input buffer.
3 . The integrated circuit of claim 1 , wherein the bridge controller is further configured to determine a communication path based on the association of the first output buffer and the second input buffer.
4 . The integrated circuit of claim 1 , wherein the bridge controller is further configured to compare the first output buffer with the second input buffer.
5 . The integrated circuit of claim 4 , wherein the comparison of the first output buffer and the second input buffer is performed to determine a transfer of a data packet.
6 . The integrated circuit of claim 5 , wherein the bridge controller is further configured to perform a data transfer operation based on the result of the comparison of the first output buffer and the second input buffer.
7 . The integrated circuit of claim 1 , wherein the bridge controller is further configured to map the first input buffer to the second output buffer and map the first output buffer to the second output buffer, thus forming a bidirectional bridge configured to pass USB traffic between the first USB host and the USB consumer device acting as the second USB host.