Receiver-side adaptive equalization in source-synchronous chip-to-chip communication systems

1. An integrated circuit to integrated circuit communication system comprising:

transmitting circuitry arranged to transmit a data signal and a timing signal; and

receiving circuitry arranged to receive the data signal and the timing signal, wherein the receiving circuitry comprises:

a first finite impulse response filter arranged to generate a filtered timing signal dependent on the timing signal and a at least one mixer signal;

a decision feedback circuit arranged to generate the at least one mixer signal dependent on the filtered timing signal and a calibration signal; and

a second finite impulse response filter arranged to generate a filtered data signal dependent on the data signal and the at least one mixer signal;

wherein the integrated circuit to integrated circuit communication system provides receiver-side adaptive equalization for source-synchronous chip-to-chip communications.

2. The communication system of claim 1 , wherein the first finite impulse response filter and a second finite impulse response filter is a digital filter.

3. The communication system of claim 2 , wherein the first digital finite impulse response filter comprises a first mixer circuitry arranged to generate a filtered timing signal dependent on the timing signal and the at least one mixer signal.

4. The communication system of claim 2 , wherein the first digital finite impulse response filter, comprising:

a first mixer circuitry arranged to generate a modified timing signal dependent on the timing signal and a first mixer signal;

a delay circuit arranged to generate a delayed timing signal dependent on the timing signal; and

a second mixer circuitry arranged to generate the filtered timing signal dependent on the delayed timing signal, a second mixer signal, and the modified timing signal.

5. The communication system of claim 2 , wherein the second digital finite impulse response filter comprises a first mixer circuitry arranged to generate a filtered timing signal dependent on the timing signal and the at least one mixer signal.

6. The communication system of claim 2 , wherein the second digital finite impulse response filter, comprising:

a first mixer circuitry arranged to generate a modified timing signal dependent on the timing signal and a first mixer signal;

a delay circuit arranged to generate a delayed timing signal dependent on the timing signal; and

a second mixer circuitry arranged to generate the filtered timing signal dependent on the delayed timing signal and a second mixer signal.

7. The communication system of claim 2 , wherein the first digital finite impulse, comprises:

an analog to digital converter arranged to generate a digitized timing signal dependent on the timing signal;

a digital signal processor arranged to generate a filtered digitized timing signal dependent on the digitized timing signal and the at least one mixer signal; and

a digital to analog converter arranged to generate the filtered timing signal dependent on the filtered digitized timing signal.

8. The communication system of claim 2 , wherein the second digital finite impulse, comprises:

an analog to digital converter arranged to generate a digitized data signal dependent on the data signal;

a digital signal processor arranged to generate a filtered digitized data signal dependent on the digitized data signal and the at least one mixer signal; and

a digital to analog converter arranged to generate the filtered data signal dependent on the filtered digitized data signal.

9. The communication system of claim 1 , wherein the decision feedback circuit, comprises:

a comparator arranged to generate an error signal dependent on the calibration signal and the filtered timing signal;

a state machine arranged to generate an equalization signal dependent on the error signal; and

a parsing circuitry arranged to generate at least one mixer signal dependent on the equalization signal.

10. The communication system of claim 9 , wherein the calibration signal is the timing signal.

11. The communication system of claim 1 , wherein a number of mixer circuits in the first digital finite impulse response filter is equal to a number of mixer circuits in the second finite impulse response filter.

12. The communication system of claim 1 , wherein the system uses an execution mode.

13. The communication system of claim 1 , wherein the system uses a test mode.

14. A method for synchronizing a receiver-side integrated circuit to integrated circuit communication system, comprising:

transmitting a timing signal and a data signal from transmitting circuitry;

receiving the timing signal and the data signal comprising:

inputting a timing signal to a first finite impulse response filter;

inputting a data signal to a second finite impulse response filter;

generating a filtered timing signal from the first finite impulse response filter;

inputting the filtered timing signal and a calibration signal to a decision feedback circuit;

generating at least one mixer signal from the decision feedback circuit; and

inputting the at least one mixer signal to the first finite impulse response filter and the second finite impulse response filter;

wherein the integrated circuit to integrated circuit communication system provides receiver-side adaptive equalization for source-synchronous chip-to-chip communications.

15. The method of claim 14 , wherein the inputting the at least one mixer signal to the first digital finite impulse response filter, comprises:

inputting the at least one mixer signal and the timing signal to a first mixer circuit;

producing a filtering effect in response to the at least one mixer signal and the timing signal; and

generating the filtered timing signal in response to the filtering effect.

16. The method of claim 14 , wherein inputting a timing signal comprises multiplying the timing signal by a filter coefficient; and

wherein inputting a data signal comprises multiplying the data signal by a filter coefficient.

17. The method of claim 14 , wherein inputting the at least one mixer signal to the first digital finite impulse response filter, comprises:

inputting a first mixer signal and timing signal to a first mixer circuit;

producing a first filtering effect responsive to the first mixer signal and timing signal;

inputting the timing signal to a delay circuit;

generating a delayed timing signal using the delay circuit;

inputting a second mixer signal and the delayed timing signal to a second mixer circuit;

producing a second filtering effect responsive to the second mixer signal and the delayed timing signal;

generating a filtered timing signal responsive to the first and second filtering effect.

18. The method of claim 14 , wherein the inputting the at least one mixer signal to the second digital finite impulse response filter, comprises:

inputting the at least one mixer signal and the data signal to a mixer circuit;

producing the a filtering effect in response to the at least one mixer signal and the timing signal; and

generating the filtered data signal in response to the filtering effect.

19. The method in one of the claims 18 , wherein inputting comprises multiplying the data signal by a filter coefficient.

20. The method of claim 14 , wherein inputting the at least one mixer signal to the second digital finite impulse response filter, comprises:

inputting a first mixer signal and data signal to a first mixer circuit;

producing a first filtering effect responsive to the first mixer signal and data signal;

inputting the data signal to a delay circuit;

generating a delayed data signal using the delay circuit;

inputting a second mixer signal and the delayed data signal to a second mixer circuit;

producing a second filtering effect responsive to the second mixer signal and the delayed data signal;

generating a filtered data signal responsive to the first and second filtering effect.

21. The method of claim 14 , wherein the inputting the at least one mixer signal to the first digital finite impulse response filter associated with the clock line, comprises:

inputting the timing signal to an analog to digital converter;

generating a digitized timing signal;

inputting the digitized timing signal and the at least one mixer signal to a digital signal processor;

calculating a filtering effect responsive to the at least one mixer signal and the digitized timing signal;

generating a filtered digitized timing signal responsive to the filtering effect;

inputting the filtered digitized timing signal to a digital to analog converter; and

outputting a filtered timing signal.

22. The method of claim 14 , wherein the inputting the at least one mixer signal to the first digital finite impulse response filter associated with the clock line, comprises:

inputting the timing signal to an analog to digital converter;

generating a digitized timing signal;

inputting the digitized timing signal and the at least one mixer signal to a digital signal processor;

calculating a filtering effect responsive to the at least one mixer signal and the digitized timing signal;

generating a filtered digitized timing signal responsive to the filtering effect;

inputting the filtered digitized timing signal to a digital to analog converter; and

outputting a filtered timing signal.

23. The method of claim 15 , wherein the generating the at least one mixer signal, comprises:

inputting a calibration signal and the filtered timing signal to a comparator;

generating an error signal from the comparator;

inputting the error signal to a state machine;

generating an equalizing signal from the state machine;

inputting the equalizing signal to a parsing circuit; and

generating the at least one mixer signal from the parsing circuit.

24. The method of claim 15 , wherein the synchronizing of the communication system occurs in execution mode.

25. The method of claim 15 , wherein the synchronizing of the communication system occurs in test mode.

26. An integrated circuit to integrated circuit communication system comprising:

means for transmitting circuitry arranged to transmit a data signal and a timing signal; and

means for receiving circuitry arranged to receive the data signal and the timing signal, wherein the receiving circuitry comprises:

a first means for outputting a filtered timing signal dependent on the timing signal and a mixer signal;

means for generating at least one mixer signal dependent on the filtered timing signal; and

a second means for outputting a filtered data signal dependent on the data signal and the at least one mixer signal;

wherein the integrated circuit to integrated circuit communication system provides receiver-side adaptive equalization for source-synchronous chip-to-chip communications.