System and method for compensating for skew between a first clock signal and a second clock signal
First Claim
1. A system for compensating for skew in a programmable clock synchronizer for effectuating data transfer between first circuitry disposed in a first clock domain and second circuitry disposed in a second clock domain, wherein said first clock domain is operable with a first clock signal and said second clock domain is operable with a second clock signal, said first and second clock signals having a ratio of N first clock cycles to M second clock cycles, where N/M≧
- 1, the system comprising;
a phase detector operable to detect a phase difference between said first clock signal and said second clock signal;
a skew state detector disposed in communication with said phase detector for generating a skew state signal which tracks a phase relationship between said first clock signal and said second clock signal relative to a zero point of a timing window corresponding to said second clock signal; and
a synchronizer control signal generator, responsive to said skew state signal, for generating at least one control signal according to a value of said skew state signal.
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Abstract
A system and method for compensating for skew in a programmable clock synchronizer for effectuating data transfer between first circuitry disposed in a first clock domain and second circuitry disposed in a second clock domain. In a system embodiment, a phase detector is provided for detecting a phase between the first and second clock signals. A skew state detector disposed in communication with the phase detector is operable to generate a skew state signal which tracks a phase relationship between the clock signals. A synchronizer control signal generator responds to the skew state signal by generating at least one control signal to compensate for the skew between the first clock signal and the second clock signal.
42 Citations
20 Claims
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1. A system for compensating for skew in a programmable clock synchronizer for effectuating data transfer between first circuitry disposed in a first clock domain and second circuitry disposed in a second clock domain, wherein said first clock domain is operable with a first clock signal and said second clock domain is operable with a second clock signal, said first and second clock signals having a ratio of N first clock cycles to M second clock cycles, where N/M≧
- 1, the system comprising;
a phase detector operable to detect a phase difference between said first clock signal and said second clock signal; a skew state detector disposed in communication with said phase detector for generating a skew state signal which tracks a phase relationship between said first clock signal and said second clock signal relative to a zero point of a timing window corresponding to said second clock signal; and a synchronizer control signal generator, responsive to said skew state signal, for generating at least one control signal according to a value of said skew state signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- 1, the system comprising;
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9. A method for compensating for skew in a programmable clock synchronizer for effectuating data transfer between first circuitry disposed in a first clock domain and second circuitry disposed in a second clock domain, wherein said first clock domain is operable with a first clock signal and said second clock domain is operable with a second clock signal, said first and second clock signals having a ratio of N first clock cycles to M second clock cycles, where N/M≧
- 1, the method comprising;
determining a phase difference between said first clock signal and said second clock signal relative to a zero point of a timing window corresponding to said second clock signal; deciding if a state transition is necessary based on a result of said determining step; and generating a control signal indicative of said state transition, thereby compensating for said skew between said first clock signal and said second clock signal. - View Dependent Claims (10, 11, 12, 13, 14)
- 1, the method comprising;
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15. A computer system having an apparatus for compensating for skew in a programmable clock synchronizer for effectuating data transfer between first circuitry disposed in a first clock domain and second circuitry disposed in a second clock domain, wherein said first clock domain is operable with a first clock signal and said second clock domain is operable with a second clock signal, said first and second clock signals having a ratio of N first clock cycles to M second clock cycles, where N/N≧
- 1, the computer system comprising;
means for determining a phase difference between said first clock signal and said second clock signal relative to a zero point of a timing window corresponding to said second clock signal; means for deciding if a state transition is necessary based on a result of said determining; and means for generating a control signal indicative of said state transition, thereby compensating for said skew between said first clock signal and said second clock signal. - View Dependent Claims (16, 17, 18, 19, 20)
- 1, the computer system comprising;
Specification