Apparatus for measuring signal skew of asynchronous flash memory controller
View Patent ↗A method of measuring skew between signals from an asynchronous integrated flash memory controller (IFC) includes connecting input/output (I/O) pins of the IFC to cycle based test equipment (ATE). The ATE applies a pattern of test signals as input drive to the IFC. Relative to the test cycle, the earliest delay time at which output signals from all of the I/O pins first correspond with expected results, and the latest delay time at which the output signals still correspond with the expected results are measured. The difference between the latest and the earliest delay times is compared with a limit value and a comparison report is generated.
1. A tester for measuring skew between signals from an asynchronous integrated flash memory controller (IFC) having a plurality of input/output (I/O) pins, the tester comprising:
a test pattern generator for providing a cyclical pattern of test signals as input drive to the I/O pins;
a delay measurement module for measuring the earliest delay time relative to the test cycle at which output signals from all the plurality of I/O pins first correspond with expected results and the latest delay time relative to the test cycle at which the output signals from all the plurality of I/O pins still correspond with the expected results; and
a comparison module for comparing with a limit value the difference between the latest and the earliest delay times and generating a report of the comparison,
wherein the delay measurement module measuring the latest delay time includes:
measuring the earliest delay time relative to the test cycle at which an output signal from the plurality of I/O pins no longer corresponds with the expected results, and
saving an earlier delay time relative to the test cycle at which the output signals from all the plurality of I/O pins still correspond with the expected results.
2. The tester of claim 1 , wherein the test pattern generator provides a reference signal having a frequency equal to a test cycle of the pattern of test signals, and the delay measurement module measures the delay times relative to the reference signal.
3. The tester of claim 1 , wherein the delay measurement module measuring the earliest and latest delay times includes edge searching the output signals from all the plurality of I/O pins.
4. The tester of claim 1 , wherein the delay measurement module registering the earlier delay time includes subtracting a cycle period of the test equipment from the earliest delay time and registering the result of the subtraction.
5. A method of measuring skew between signals from an asynchronous integrated flash memory controller (IFC), the method comprising:
connecting a plurality of input/output (I/O) pins of the IFC to a cycle based test equipment;
applying a cyclical pattern of test signals as an input to drive to the IFC, using the test equipment;
measuring the earliest delay time relative to the test cycle at which output signals from all of the plurality of I/O pins first correspond with expected results;
measuring the latest delay time relative to the test cycle at which the output signals from all of the plurality of I/O pins still correspond with the expected results; and
comparing with a limit value the difference between the latest and the earliest delay times and generating a report of the comparison,
wherein measuring the latest delay time includes measuring the earliest delay time relative to the test cycle at which an output signal from the plurality of I/O pins no longer corresponds with the expected results, and saving an earlier delay time relative to the test cycle at which the output signals from all the plurality of I/O pins still correspond with the expected results.
6. The method of claim 5 , wherein the test equipment provides a reference signal having a frequency equal to a test cycle of the pattern of test signals, and the delay times are measured relative to the reference signal.
7. The method of claim 5 , wherein measuring the earliest and latest delay times includes edge searching the output signals from all the plurality of I/O pins.
8. The method of claim 5 , wherein registering the earlier delay time includes subtracting a cycle period of the test equipment from the earliest delay time and registering the result of the subtraction.
9. A non-transitory computer-readable storage medium storing instructions that, when executed by test equipment connected to a plurality of input/output (I/O) pins of an asynchronous integrated flash memory controller (IFC), cause the test equipment to perform a method of measuring skew between signals from the IFC, the method comprising:
the test equipment applying a cyclical pattern of test signals as input drive to the IFC;
measuring the earliest delay time relative to the test cycle at which output signals from all the plurality of I/O pins first correspond with expected results;
measuring the latest delay time relative to the test cycle at which the output signals from all the plurality of I/O pins still correspond with the expected results; and
comparing with a limit value the difference between the latest and the earliest delay times and generating a report of the comparison, and
wherein measuring the latest delay time includes the test equipment measuring the earliest delay time relative to the test cycle at which an output signal from the plurality of I/O pins no longer corresponds with the expected results, and saving an earlier delay time relative to the test cycle at which the output signals from all the plurality of I/O pins still correspond with the expected results.
10. The non-transitory computer-readable storage medium of claim 9 , wherein the test equipment provides a reference signal having a frequency equal to a test cycle of the pattern of test signals, and the delay times are measured relative to the reference signal.
11. The non-transitory computer-readable storage medium of claim 9 , wherein measuring the earliest and latest delay times includes the test equipment edge searching the output signals from all the plurality of I/O pins.
12. The non-transitory computer-readable storage medium of claim 9 , wherein registering the earlier delay time includes the test equipment subtracting a cycle period of the test equipment from the earliest delay time and registering the result of the subtraction.