Fast link turnaround using MIPI D-PHY

An apparatus comprising:

• a two-wire link;
• a bidirectional physical interface adapted to convert data to sequences of two-phase symbols for transmission on the two-wire link and to convert sequences of two-phase symbols received on the two-wire link into data;
• and
• a processor configured to:
• receive and decode high-speed data on the two-wire link while operating in a high-speed communication mode, where the high-speed data is received within a first voltage range before returning to a low-power communication mode for a first time;
• decode a first sequence of only two signaling states received on the two-wire link within a second, larger voltage range during the low-power communication mode to signal a turnaround command without requiring any additional signaling state within the first voltage range, where the turnaround command enables the apparatus to transmit data over the two-wire link;
• and
• transmit, in response to the turnaround command, second high-speed data over the two-wire link in the high-speed communication mode, wherein the second high-speed data is transmitted within the first voltage range.

A method performed in a device coupled to a multi-wire interface, comprising:

• transmitting to a slave device connected to the multi-wire interface a first sequence of signaling states within a first voltage range during a low-power communication mode to cause the device to transition to a high-speed communication mode;
• transmitting to the slave device over the multi-wire interface first high-speed data within a second, smaller voltage range while operating in the high-speed communication mode before returning to the low-power communication mode for a first time;
• transmitting to the slave device over the multi-wire interface a second sequence of no more than two signaling states within the first voltage range during the low-power communication mode to signal a turnaround command without requiring any additional signaling state within the first voltage range, where the turnaround command enables the slave device to transmit data over the multi-wire interface to the device;
• receiving from the slave device over the multi-wire interface the first sequence of signaling states within the first voltage range to cause the device to transition to a high-speed communication mode for receiving data from the slave device over the multi-wire interface;
• and
• receiving from the slave device over the multi-wire interface second high-speed data within the second, smaller voltage range while operating in the high-speed communication mode before returning the multi-wire interface to the low-power communication mode for a second time.