Vector decoding in time-constrained double data rate interface

An apparatus for data communication comprising:

• an interface circuit adapted to couple the apparatus to a serial bus;
• a transition detector circuit configured to:
• detect a transition in signaling state of a first wire of the serial bus while a first pair of consecutive bits is being received from the first wire, wherein bit values for the first pair of consecutive bits are defined based on direction of the transition in the signaling state of the first wire;
• and
• determine that no transition in the signaling state of the first wire occurred while a second pair of consecutive bits is being received from the first wire;
• and
• a state sampling circuit configured to:
• sample the signaling state of the first wire while the second pair of consecutive bits is being received;
• and
• provide a sampled bit value derived from the sampled signaling state to represent a bit value for both bits in the second pair of consecutive bits.

A method of data communications, comprising:

• encoding primary data in a data signal to be transmitted over a first wire of a serial bus;
• and
• providing a phase-encoded clock signal to be transmitted over a second wire of the serial bus,
• wherein the phase-encoded clock signal provides a plurality of edges indicating when bits of the primary data are to be sampled from the first wire, and
• wherein secondary data is encoded in direction of transition of the plurality of edges.

An apparatus comprising:

• an interface circuit adapted to couple the apparatus to a serial bus;
• a first data encoder configured to:
• encode primary data in a data signal to be transmitted over a first wire of the serial bus;
• and
• a second data encoder configured to:
• provide a phase-encoded clock signal to be transmitted over a second wire of the serial bus,
• wherein the phase-encoded clock signal provides a plurality of edges indicating when bits of the primary data are to be sampled from the first wire, and
• wherein secondary data is encoded in direction of transition of the plurality of edges.