Data processing unit and a method of processing data
A data processing unit has a time information provider for processing a clock or a strobe signal, configured to provide a digitized clock or strobe time information on the basis of the clock or strobe signal and at least one data extraction unit, coupled to the time information provider and configured to select data from a sequence of data samples of a data signal depending on the digitized clock or strobe time information.
1. A data processing unit, comprising:
a time information provider including,
a first sampling unit configured to sample a clock-or-strobe signal,
a first bit history unit, coupled to the first sampling unit, and configured to temporarily store a sequence of samples of the clock-or-strobe signal, and
a transition detection unit, coupled to the first bit history unit, and configured to detect a transition in the sequence of samples to acquire a digitized clock-or-strobe time information on the basis of the sequence of samples of the clock-or-strobe signal; and
at least one data extraction unit, coupled to the time information provider, including,
a second sampling unit configured to sample a data signal to acquire data samples of the data signal,
a second bit history unit, coupled to the second sampling unit, and configured to temporarily store a sequence of the data samples of the data signal, and
a data selection unit, coupled to the second bit history unit, and configured to select data from the temporarily stored sequence of the data samples of the data signal depending on the digitized clock-or-strobe time information provided by the transition detection unit;
wherein the clock-or-strobe signal is physically different from the data signal;
wherein the time information provider comprises a time-to-digital converter configured provide, as the digitized clock-or-strobe time information, a digitized time stamp describing a time of a transition of the clock-or-strobe signal, and
wherein the digitized clock or strobe time information is represented as a multi-bit value encoding the clock or strobe time information or
wherein the digitized clock-or-strobe time information is represented as an increment-decrement-information, wherein the increment-decrement-information describes a difference between a timing of a currently detected transition of the clock-or-strobe signal and a timing of a previous transition of the clock-or-strobe signal.
2. The data processing unit according to claim 1 , wherein the first and the second sampling units are configured to sample the clock-or-strobe signal and the data signal with the same sampling rate.
3. The data processing unit according to claim 1 , wherein the digitized clock-or-strobe time information is represented by one or more discretely coded values.
4. The data processing unit according to claim 1 , wherein the data processing unit is configured to transfer the digitized clock-or-strobe time information from the time information provider to the data extraction unit synchronized with a master clock.
5. The data processing unit according to claim 1 , wherein the data processing unit is configured to transfer the digitized clock-or-strobe time information from the time information provider to the data extraction unit asynchronously with respect to a master clock.
6. The data processing unit according to claim 5 , wherein the correction unit is further configured to compensate, at least partially, buffer delays in a data path of the data signal.
7. The data processing unit according claim 1 , wherein the data processing unit is configured to transfer the digitized clock-or-strobe time information from the time information provider to the data extraction unit only once per I periods of the clock-or-strobe signal, wherein I>1.
8. The data processing unit according to claim 1 , wherein the data processing unit is configured to transfer the digitized clock-or-strobe time information from the time information provider to the data extraction unit only once per J data positions of the data signal, wherein J>1.
9. The data processing unit according to claim 1 , wherein the at least one data extraction unit is coupled to a correction unit configured to influence the selection of data from the sequence of data samples of the data signal.
10. The data processing unit according to claim 1 , wherein the at least one data extraction unit is coupled to a correction unit configured to influence the selection of data from a sequence of data samples of the data signal, such that a propagation delay difference between the clock-or-strobe signal and the data signal is at least partially compensated or such that a propagation delay of the digitized clock-or-strobe time information is at least partially compensated.
11. The data processing unit according to claim 1 , wherein the at least one data extraction unit is coupled to a correction unit configured to change the digitized clock-or-strobe time information to acquire a changed digitized clock-or-strobe time information, and wherein the data processing unit is configured to use the changed digitized clock-or-strobe time information to select data from a sequence of data samples of the data signal;
wherein the correction unit is configured to change the digitized clock-or-strobe time Information in such a way that a propagation delay difference between the clock-or-strobe signal and the data signal is compensated.
12. The data processing unit according to claim 1 , wherein the at least one data extraction unit is coupled to the time information provider in a daisy chain, in a parallel configuration or in a serial configuration, in order to acquire the digitized clock-or-strobe time information.
13. The data processing unit according to claim 1 , further comprising a clocked pipeline or a plurality of buffers to forward the digitized clock-or-strobe time information from the information provider to the at least one data extraction unit.
14. The data processing unit according to claim 1 , wherein the time information provider comprises a plurality of flip-flops to temporarily store the sequence of samples of the clock-or strobe signal, and
wherein the at least one data extraction unit comprises a plurality of flip-flops to temporarily store the sequence of data samples.
15. The data processing unit according to claim 1 , wherein the time information provider is configured to forward the digitized clock-or-strobe time information to the at least one data extraction unit as a digital word.
16. The data processing unit according to claim 1 , wherein
the first and the second sampling units are clocked with a n-fold frequency compared to the first and the second bit history units, and
the first and the second bit history units are configured to temporarily store at least the respective n-fold samples of the clock-or-strobe signal or data signal; and
n is larger than one.
17. The data processing unit according to claim 1 , wherein at least one data extraction unit comprises a multiplexer configured to select data from the sequence of data samples of the data signal depending on a multiplexer selection information, and wherein the multiplexer selection information is based on the digitized clock-or-strobe time information, or wherein the multiplexer selection information is a function of the digitized clock-or-strobe time information.
18. The data processing unit according to claim 1 , wherein the clock or strobe signal and the data signal are bit streams.
19. The data processing unit according to claim 1 , wherein clock-or-strobe signal and the data signal are source-synchronous signals.
20. A tester for testing a device-under-test, the tester comprising:
a master clock signal;
a strobe signal generator;
a device-under-test interface;
a data processing unit comprising:
a time information provider including,
a first sampling unit configured to sample a clock-or-strobe signal,
a first bit history unit, coupled to the first sampling unit, and configured to temporarily store a sequence of samples of the clock-or-strobe signal, and
a transition detection unit, coupled to the first bit history unit, and configured to detect a transition in the sequence of samples to acquire a digitized clock-or-strobe time information on the basis of the clock-or-strobe signal; and
at least one data extraction unit, coupled to the time information provider, including,
a second sampling unit configured to sample a data signal to acquire data samples of the data signal,
a second bit history unit, coupled to the second sampling unit, and configured to temporarily store a sequence of the data samples of the data signal, and
a data selection unit, coupled to the second bit history unit, and configured to select data from the temporarily stored sequence of the data samples of the data signal depending on the digitized clock-or-strobe time information provided by the transition detection unit;
wherein the clock-or-strobe signal is physically different from the data signal;
wherein the time information provider comprises a time-to-digital converter configured to provide, as the digitized clock-or-strobe time information, a digitized time stamp describing a time of a transition of the clock-or-strobe signal,
wherein the digitized clock or strobe time information is represented as a multi-bit value encoding the clock or strobe time information or
wherein the digitized clock-or-strobe time information is represented as an increment-decrement-information, wherein the increment-decrement-information describes a difference between a timing of a currently detected transition of the clock-or-strobe signal and a timing of a previous transition of the clock-or-strobe signal; and
a comparator unit;
wherein the tester is configured such that the strobe signal generator generates a strobe signal for the data processing unit on the basis of the master clock signal; and
wherein the data processing unit is coupled, via at least one data signal line, to the device-under-test interface, to receive the data signal from a device-under-test;
wherein the data-processing unit is configured to provide the selected data from the sequence of data samples of the device-under-test data signal in response to the strobe signal; and
wherein the comparator unit is configured to compare the selected data provided by the data processing unit with expected data, and to provide a test result based on the comparison of the selected data with the expected data.
21. The tester for testing a device under test according to claim 20 , wherein the strobe signal generator is configured to adjustably shift a timing of the clock-or-strobe signal in relation to the master clock signal.
22. The tester according to claim 20 , wherein the strobe signal generator comprises a frequency divider, a frequency multiplier, a phase-locked-loop (PLL), a delay-locked-loop (DLL) or an adjustable delay line.
23. The tester for testing a device-under-test according to claim 20 , wherein the tester is configured to perform the sampling of the clock-or-strobe signal and the sampling of the data signal in dependence on one or more timing responses defined by a master clock signal generated in the tester or provided to the tester, and wherein the digitized clock-or-strobe time information describes a timing of the clock-or-strobe signal relative to the master clock signal.
24. A tester for testing a device under test (DUT), the tester comprising;
a comparator unit;
a device-under-test (DUT) interface; and
a data processing unit comprising:
a time information provider including,
a first sampling unit configured to sample a clock-or-strobe signal,
a first bit history unit, coupled to the first sampling unit, and configured to temporarily store a sequence of samples of the clock-or-strobe signal, and
a transition detection unit, coupled to the first bit history unit, and configured to detect a transition in the sequence of samples to acquire a digitized clock-or-strobe time information on the basis of the sequence of samples of the clock-or-strobe signal; and
at least one data extraction unit, coupled to the time information provider, including
a second sampling unit configured to sample a data signal to acquire data samples of the data signal,
a second bit history unit, coupled to the second sampling unit, and configured to temporarily store a sequence of the data samples of the data signal, and
a data selection unit, coupled to the second bit history unit, and configured to select data from the temporarily stored sequence of the data samples of the data signal depending on the digitized clock-or-strobe time information provided by the transition detection unit;
wherein the clock-or-strobe signal is physically different from the data signal;
wherein the time information provider comprises a time-to-digital converter configured provide, as the digitized clock-or-strobe time information, a digitized time stamp describing a time of a transition of the clock-or-strobe signal,
wherein the digitized clock or strobe time information is represented as a multi-bit value encoding the clock or strobe time information or
wherein the digitized clock-or-strobe time information is represented as an increment-decrement-information, wherein the increment decrement information describes a difference between a timing of a currently detected transition of the clock-or-strobe signal and a timing of a previous transition of the clock-or-strobe signal;
wherein the data processing unit is coupled to the DUT interface to receive from the DUT interface the data signal and the clock-or-strobe signal, and to select data from the sequence of data samples of the data signal, in response to the clock-or-strobe signal; and
wherein the comparator unit is configured to compare the selected data provided by the processing unit with expected data, and to provide a test result based on the comparison of the selected data with expected data.
25. The test for testing a device-under-test, according to claim 24 , wherein the tester is configured to perform the sampling of the clock-or-strobe signal and the sampling of the data signal in dependence on one or more timing responses defined by a master clock signal generated in the tester or provided to the tester, and wherein the digitized clock-or-strobe time information describes a timing of the clock-or-strobe signal relative to the master clock signal.
26. The tester according to claim 24 ; further comprising a data generator unit coupled to the DUT interface and to the comparator unit, wherein the data generator unit is configured to generate data signals, to provide the data signals to the DUT interface, and to generate an information about the expected data.
27. The tester according to claim 24 , further comprising a data generator unit coupled to the DUT interface and to the comparator unit, wherein the data generator unit is configured to generate data signals, to provide the data signals to the DUT interface, and to generate an information about the expected data.
28. A method of processing data, comprising:
processing a clock or strobe signal, to sample a clock-or strobe signal, to temporarily store a sequence of samples of the clock-or-strobe signal and detect a transition in the sequence of samples to acquire a digitized clock-or-strobe time information on the basis of the sequence of samples of the clock or strobe signal; and
selecting data from a sequence of data samples of a data signal, to temporarily store a sequence of the data samples of the data signal and select data from the temporarily stored sequence of the data samples of the data signal depending on the digitized clock or strobe time information;
wherein the clock-or-strobe signal is physically different from the data signal;
wherein providing the digitized clock or strobe time information comprises providing, as the digitized clock or strobe time information, a digitized time stamp describing a time of a transition of the clock-or-strobe signal;
wherein the digitized clock or strobe time information is represented as a multi-bit value encoding the clock or strobe time information or
wherein the digitized clock-or-strobe time information is represented as an increment-decrement-information, wherein the increment-decrement-information describes a difference between a timing of a currently detected transition of the clock-or-strobe signal and a timing of a previous transition of the clock-or-strobe signal.
29. The method of processing data according to claim 28 , wherein processing a clock-or-strobe signal comprises sampling the clock or strobe signal with a first sampling frequency f S1 , which is n-times higher than a first maximum frequency f max1 of the clock or strobe signal to acquire samples of the clock-or-strobe signal and identifying a transition of the clock-or-strobe signal using the samples of the clock-or-strobe signal; and
wherein selecting data from the sequence of data samples comprises sampling the data signal with a second sampling frequency f S2 which is m-times higher than a maximum frequency f max2 of the data signal to acquire the sequence of samples; and wherein n≧2 and m≧2.
30. The method of processing data according to claim 28 , wherein the sampling of the clock-or-strobe signal and the sampling of the data signal is performed with the same sampling frequency.
31. A computer program for performing a method of processing data comprising:
processing a clock or strobe signal, to sample a clock-or strobe signal, to temporarily store a sequence of samples of the clock-or-strobe signal and detect a transition in the sequence of samples to acquire a digitized clock or strobe time information on the basis of the sequence of samples of the clock or strobe signal; and
selecting data from a sequence of data samples of a data signal, to temporarily store a sequence of the data samples of the data signal and select data from the temporarily stored sequence of the data samples of the data signal depending on the digitized clock or strobe time information;
wherein the clock-or-strobe signal is physically different from the data signal;
wherein providing the digitized clock or strobe time information comprises providing, as the digitized clock or strobe time information, a digitized time stamp describing a time of a transition of the clock-or-strobe signal;
wherein the digitized clock or strobe time information is represented as a multi-bit value encoding the clock or strobe time information or
wherein the digitized clock-or-strobe time information is represented as an increment-decrement-information, wherein the increment-decrement-information describes a difference between a timing of a currently detected transition of the clock-or-strobe signal and a timing of a previous transition of the clock-or-strobe signal, when the computer program runs on a computer.