Clock phase adjustment using clock and data recovery scheme
Some embodiments include apparatus and methods using clock generation circuitry to generate a first clock signal and a second clock signal based on an input clock signal, the first and second clock signals having different phases, sampler circuitry to sample an input signal based on timing of the first and second clock signals and provide data information and error information associated with sampling of the input signal, a clock and data recovery unit to generate first control information based on the data information and the error information, and a phase error detection unit to generate second control information based on the data information and the error information, the clock generation circuitry to control timing of the input clock signal based on the first control information and to control timing of the first and second clock signals based on the second control information.
1. An apparatus comprising:
clock generation circuitry to generate a first clock signal and a second clock signal based on an input clock signal, the first and second clock signals having different phases;
sampler circuitry to sample an input signal based on timing of the first and second clock signals and provide data information and error information associated with sampling of the input signal;
a clock and data recovery unit to generate first control information based on the data information and the error information; and
a phase error detection unit to generate second control information based on the data information and the error information, the clock generation circuitry to control timing of the input clock signal based on the first control information and to control timing of the first and second clock signals based on the second control information, wherein the sampler circuitry include first sampler circuits having inputs to receive the input signal, and second sampler circuits having inputs to receive the input signal, and the phase error detection unit includes a first phase detector having inputs coupled to outputs of the first sampler circuits, and a second phase detector having inputs coupled to outputs of the second sampler circuits.
2. The apparatus of claim 1 , wherein the phase error detection unit includes:
a first summer coupled to the first phase detector; and
a second summer coupled to the second phase detector.
3. The apparatus of claim 1 , wherein the clock generation circuitry includes a phase rotator to receive the first control information in order to adjust timing of the input clock signal.
4. The apparatus of claim 3 , wherein the clock generation circuitry includes a first delay line to generate the first clock signal, and second delay line to generate the second clock signal, and the first and second delay lines are to adjust timing of the first and second clock signals, respectively, based on the second control information.
5. The apparatus of claim 1 , wherein the clock and data recovery unit includes a baud-rate clock and data recovery unit.
6. An apparatus comprising:
an input to receive an input signal;
an input clock generator to generate an input clock signal;
first and second clock generators to generate a first clock signal and a second clock signal, respectively, based on the input clock signal, the first and second clock signals having different phases;
sampler circuitry to sample the input signal based on timing of the first and second clock signals and provide data information and error information associated with the sampling of the input signal;
a clock and data recovery unit to generate first control information based on the data information and the error information and provide the first control information to the input clock generator; and
a phase error detection unit to generate second control information based on the data information and the error information and to provide the second control information to the first and second clock generators, wherein the sampler circuitry includes:
a first circuit path to sample the input signal based on timing of the first clock signal and provide a first portion of the data information and a first portion of error information; and
a second circuit path to sample the input signal based on timing of the second clock and provide a second portion of the data information and a second portion of the error information.
7. The apparatus of claim 6 , wherein the first and second clock generators are to generate the first clock signal having a first phase difference with the input clock signal and to generate the second clock signal having a second phase difference with the input clock signal, and at least one of the first and second phase differences is a multiple of 90 degrees.
8. The apparatus of claim 6 , wherein the first and second clock generators include:
a first delay line to delay the input clock signal in order to generate the first clock signal; and
a second delay line to delay the input clock signal in order to generate the second clock signal.
9. The apparatus of claim 8 , wherein the first delay line is to delay the input clock signal by an amount of delay based on a value of a first portion the second control information, and the second delay line is to delay the input clock signal by an amount of delay based on a value of a second portion of the second control information.
10. The apparatus of claim 6 , wherein each of the first and second circuit path include a first sampler circuit to sample the input signal and a second sampler circuit to sample the input signal.