Sideband signaling in universal serial bus (USB) type-C communication links

An integrated circuit (IC), comprising:

• a communication link interface comprising:
• a two-wire interface comprising a low-speed interface;
• and
• a high-speed interface operative at a high speed greater than a low speed associated with the low-speed interface;
• and
• a control circuit coupled to the communication link interface and configured to:
• use a current mode based messaging over the low-speed interface to negotiate a transition to a new mode for communications with a remote IC over the two-wire interface, wherein a first protocol corresponds to the current mode;
• transition to using a new protocol corresponding to the new mode;
• operate using the new protocol;
• subsequently, change operation from the second protocol back to the first protocol using the new mode based messaging;
• while in an idle mode, hold at least one wire of the two-wire interface in a default idle mode;
• determine that a wake up is needed;
• wake up the IC;
• and
• drive the at least one wire of the two-wire interface to initiate the wake up at the remote IC.

A computing system comprising:

• a communication bus including a two-wire bus and a high-speed bus operative at a high speed greater than a low speed associated with the two-wire bus;
• a first integrated circuit (IC), comprising:
• a first two-wire interface coupled to the two-wire bus;
• a high-speed interface coupled to the high-speed bus;
• and
• a first control circuit coupled to the first two-wire interface and configured to:
• using an initial protocol_transmitting messages, negotiate a transition to a second protocol for communications with a secondary IC over the first two-wire interface;
• transition to using the second protocol;
• operate using the second protocol;
• and
• subsequently change back to using the initial protocol;
• and
• the secondary IC comprising:
• a secondary two-wire interface coupled to the two-wire bus;
• and
• a secondary control circuit coupled to the secondary two-wire interface and configured to:
• responsive to negotiations from the first control circuit, transition to using the second protocol;
• and
• operate using the second protocol.