Clock recovery apparatus, method, and system

1. An apparatus comprising:

a first loop circuit to receive a reference clock and produce at least one internal clock signal;

a plurality of second loop circuits, wherein each of the plurality of second loop circuits is coupled to receive the at least one internal clock signal and a data signal, and to provide a phase offset indication; and

a finite state machine to receive the phase offset indication from each of the plurality of second loop circuits, and to provide phase adjustment information to each of the plurality of second loop circuits;

wherein each of the plurality of second loop circuits include a storage element to hold static phase adjustment information, and wherein the first loop circuit comprises a frequency locked loop circuit, and the finite state machine is coupled to the frequency locked loop circuit to provide dynamic phase adjustment information.

2. The apparatus of claim 1 wherein each of the plurality of second loop circuits includes a phase detector to provide the phase offset indication.

3. The apparatus of claim 1 wherein the first loop circuit includes a voltage controlled oscillator to provide a plurality of internal clock signals.

4. The apparatus of claim 3 wherein each of the plurality of second loop circuits includes an interpolator to interpolate between the plurality of internal clock signals.

5. An integrated circuit comprising:

a port circuit including a plurality of loop circuits to receive a plurality of data signals; and

a global clock recovery circuit coupled to receive a reference signal and to recover a clock frequency from the reference signal, and further coupled to receive phase offset information from each of the plurality of loop circuits;

wherein the global clock recovery circuit includes a phase locked loop to create a plurality of clock signals having a fixed phase relationship with respect to each other, and wherein each of the plurality of loop circuits includes an interpolator circuit to interpolate between the plurality of clock signals, and wherein each of the plurality of loop circuits further includes a phase detector to provide the phase offset information, and wherein the phase detector is coupled to receive a data signal and an output of the interpolator, and wherein the global clock recovery circuit comprises a finite state machine to receive the phase offset information from each of the plurality of loop circuits, and wherein the finite state machine averages the phase offset information and provides a result to each of the plurality of loop circuits.

6. A method comprising:

receiving a reference clock signal;

receiving a training sequence on a plurality of data input nodes;

recovering a clock frequency from the reference clock signal;

determining a separate static phase adjustment for each of the plurality of data input nodes, the static phase adjustment for a clock signal to clock a data signal on each of the plurality of data input nodes;

programming at least one storage element corresponding to each of the plurality of data input nodes; and

determining a common dynamic phase adjustment to combine with the separate static phase adjustments.

7. The method of claim 6 wherein determining a common dynamic phase adjustment comprises averaging phase offset information received from circuits coupled to each of the plurality of data input nodes.

8. An apparatus comprising:

a first loop circuit to receive a reference clock and produce at least one internal clock signal;

a plurality of second loop circuits, wherein each of the plurality of second loop circuits is coupled to receive the at least one internal clock signal and a data signal, and to provide a phase offset indication; and

a finite state machine to receive the phase offset indication from each of the plurality of second loop circuits, and to provide phase adjustment information to each of the plurality of second loop circuits;

wherein each of the plurality of second loop circuits include a storage element to hold static phase adjustment information, and wherein each of the plurality of second loop circuits include an adder to sum the static phase adjustment information with dynamic phase adjustment information provided by the finite state machine.

9. The apparatus of claim 8 wherein each of the plurality of second loop circuits includes a phase detector to provide the phase offset indication.

10. The apparatus of claim 8 wherein the first loop circuit includes a voltage controlled oscillator to provide a plurality of internal clock signals.

11. The apparatus of claim 10 wherein each of the plurality of second loop circuits includes an interpolator to interpolate between the plurality of internal clock signals.

12. An integrated circuit comprising:

a port circuit including a plurality of loop circuits to receive a plurality of data signals; and

a global clock recovery circuit coupled to receive a reference signal and to recover a clock frequency from the reference signal, the global clock recovery circuit including a circuit to receive and average phase offset information from each of the plurality of loop circuits, and to provide a result to each of the plurality of loop circuits.

13. The integrated circuit of claim 12 wherein the global clock recovery circuit includes a phase locked loop to create a plurality of clock signals having a fixed phase relationship with respect to each other.

14. The integrated circuit of claim 13 wherein each of the plurality of loop circuits includes an interpolator circuit to interpolate between the plurality of clock signals.

15. The integrated circuit of claim 14 wherein each of the plurality of loop circuits further includes a phase detector to provide the phase offset information.

16. The integrated circuit of claim 15 wherein the phase detector is coupled to receive a data signal and an output of the interpolator.