Extremely high frequency systems and methods of operating the same to establish USB data transport protocols
EHF communication systems described herein can selectively implement any one of the USB standards by mapping appropriate USB signal conditions over an EHF contactless communication link. The EHF contactless communication link may serve as an alternative to conventional board-to-board and device-to-device connectors, and as such enables wired connection USB signaling protocols to be used in a non-wired environment provided by the EHF contactless communications link. Use of a USB protocol over the EHF communications link can be accomplished by establishing the EHF link between counterpart EHF communication units, and then by establishing the appropriate USB protocol over the link.
1. A method for resolving a USB mode for use by a first contactless communications unit (CCU), the method implemented by the first CCU, the method comprising:
receiving a capabilities message from a second CCU over a contactless communications link, wherein the message comprises second CCU USB parameters;
retrieving first CCU USB parameters from the first CCU;
comparing the first CCU USB and second CCU USB parameters to resolve which one of a plurality of USB modes the first CCU should use; and
selecting a USB mode based on the resolution, wherein selecting the USB mode comprises:
when the first CCU USB parameter is USB 3/2 Auto:
performing Rx detect to confirm whether USB 3 is possible;
if USB 3 is determined to be possible, establishing a USB 3 connection;
if USB 3 is determined not to be possible, attempting to establish a USB 2 connection; and
failing to establish a USB connection if the USB 3 or USB 2 connection is not established.
2. The method of claim 1 , further comprising:
determining whether the first CCU is associated with one of a host and a device.
3. The method of claim 2 , wherein the first CCU comprises a first pin and wherein the first CCU executes a first CCU state machine that tracks a state of the first CCU during the establishment of a contactless communications link with the second CCU, wherein the determining comprises:
obtaining a value of the first pin at a first CCU state;
obtaining a value of the first pin at a second CCU state; and
identifying whether the first CCU is associated with one of a host and a device based on the values obtained at the first and second CCU states.
4. The method of claim 2 , wherein the host comprises a USB-only host or a USB On-the-Go host.
5. The method of claim 2 , wherein the device comprises a USB-only device or a USB On-the-Go Device.
6. The method of claim 1 , wherein the first CCU USB and second CCU USB parameters comprise parameters selected from USB 3, USB 2, and USB 3/2 Auto.
7. The method of claim 1 , wherein when the first CCU USB parameters and the second CCU USB parameters are both USB 2 parameters, the resolved USB mode is USB 2.
8. The method of claim 1 , wherein when the first CCU USB parameters and the second CCU USB parameters are both USB 3 parameters, the resolved USB mode is USB 3.
9. The method of claim 1 , wherein (1) when the first CCU USB parameter is USB 2 and the second CCU USB parameter is USB 3, or (2) when the first CCU USB parameter is USB 3 and the second CCRU USB parameter is USB 2, the resolved USB mode is failed.
10. The method of claim 1 , wherein when the first CCU parameter is USB 3/2 Auto and the second CCU parameter is USB 2, the method comprises:
resolving the USB mode to USB 2.
11. A method for resolving a USB mode for use by a first contactless communications unit (CCU), the method implemented by the first CCU, the method comprising:
receiving a capabilities message from a second CCU over a contactless communications link, wherein the message comprises second CCU USB parameters;
retrieving first CCU USB parameters from the first CCU, wherein the first CCU comprises at least one pin; and
comparing the first CCU USB and second CCU USB parameters to resolve which one of a plurality of USB modes the first CCU should use, wherein when the first CCU parameter is USB 3/2 Auto and the second CCU parameter is USB 3:
verifying at least one pin is associated with a USB 3 controller; and
resolving the USB mode to be USB 3 if the verifying passes.
12. The method of claim 11 , wherein if the verifying fails, the method comprises verifying, on a second attempt, that the at least one pin is associated with a USB 3 controller;
resolving the USB mode to be USB 3 if the verifying passes the second verification attempt; and
if the second verification attempt fails, failing to resolve a USB mode.
13. A method for resolving a USB mode for use by a first contactless communications unit (CCU), the method implemented by the first CCU, the method comprising:
receiving a capabilities message from a second CCU over a contactless communications link, wherein the message comprises second CCU USB parameters;
retrieving first CCU USB parameters from the first CCU, wherein the first CCU comprises at least one pin; and
comparing the first CCU USB and second CCU USB parameters to resolve which one of a plurality of USB modes the first CCU should use, wherein when the first CCU parameter is USB 3/2 Auto and the second CCU parameter is USB 3/2 Auto:
verifying at least one pin is associated with a USB 3 controller; and
resolving the USB mode to be USB 3 if the verifying passes.
14. The method of claim 13 , wherein if the verifying fails, the method further comprises verifying, on a second attempt, that the at least one pin is associated with a USB 3 controller;
resolving the USB mode to be USB 3 if the verifying passes the second verification attempt; and
if the second verification attempt fails, resolving the USB mode to USB 2.
15. A method for resolving a USB mode for use by a first contactless communications unit (CCU), the method, implemented in the first CCU, comprising:
beaconing a contactless signal to alert a second CCU of the first CCU;
receiving a signal from the second CCU over a contactless communications link that specifies one of a first USB capable parameter;
selecting a first USB mode based on the received signal, wherein selecting the first USB mode comprises:
when the USB capability of the first CCU is USB 3/2 Auto:
performing Rx detect to resolve the selected first USB mode to USB 3 when the first received USB parameter is USB 3;
resolving the selected first USB mode to USB 2 when the first received USB parameter is USB 2; and
performing Rx detect to resolve the selected first USB mode to USB 3 when the received first USB parameter is USB 3/2; and
transmitting the selected first USB mode to the second CCU over the contactless communications link.
16. The method of claim 15 , wherein the first CCU USB capable parameter comprises USB 3/2 Auto, USB 3, and USB 2.
17. The method of claim 15 , wherein the selected first USB mode is one of USB 3 and USB 2.
18. The method of claim 15 , further comprising:
determining that the accessing is unable to resolve to the selected first USB mode; and
selecting a second USB mode in response to the determination that the accessing is unable to resolve to the selected first USB mode.
19. The method of claim 15 , wherein the first CCU USB capable parameter represents the USB mode capability of a USB controller associated with the second CCU.
20. The method of claim 15 , wherein the selected first USB mode represents a negotiated USB mode based on USB capabilities of a controller associated with the first CCU and USB capabilities of a USB controller associated with the second CCU, wherein the negotiated USB mode is determined by the first CCU.