Test Cases for the Wall Clock and GTC Drift Test (Windows Embedded CE 6.0)
1/6/2010
The Wall Clock Drift Tests consist of manual (semi-automated) test cases. Use the Wall Clock Drift Tests to measure drift on individual clocks. A good way to use the Wall Clock Drift Tests is to run the Compare All Three Timers Drift Test with Busy Sleep to confirm the clocks do not drift relative to each other, and run at least one of the individual drift tests to confirm that the clock does not drift relative to outside sources. Ideally, one would compare the RTC, since this clock is not expected to drift with respect to outside clock.
The following table shows the test cases for the Wall Clock and GTC Drift Test.
Note
If a tested clock does not run accurately, the expected duration of a test case shown in the following table might not be accurate.
| Test case | Description |
|---|---|
1 |
Timer Test Usage Message Prints out the usage message for the OAL Timer Tests. Tells the user what the tests do and specifies the input if any that the user needs to provide to the tests. |
6010 |
6010: Wall Clock Drift Test GTC (manual) 6020: Wall Clock Drift Test Hi Perf (manual) 6030: Wall Clock Drift Test RTC (manual) Measure drift on individual clocks. The tests allow one to compare the timers on the target device to external clock sources. These test cases can be used to catch a condition where the clocks for the GetTickCount function, the high-performance counter, and the Real-Time Clock agree with each other but do not keep accurate time. This condition might occur if all three clocks derive from a common clock that does not keep accurate time. The default run time for each of these test cases is 3 hours. This can be changed using -c "-wcRunTime seconds", where seconds is the run time for the test in seconds. Before starting one of these tests, obtain a stopwatch or other external clock that you can use to measure the length of events during the test. The test case displays a start time, waits for the length of time that you specified in the command line, and then displays a stop time. The test displays messages that tell you when to start your stopwatch, and then periodically displays messages that tell you how much time remains for the test to end. Observe these messages and prepare to stop the stopwatch when the test completes. The test displays messages more frequently when the test nears completion. If the time that you record is the same as the time reported by the test, the clock kept accurate time. If the time that you record differs from the time reported by the test the clock does not keep accurate time. These test cases display the following error message if a timer suddenly jumps forward in time during the test: ERROR: The current time overshot the stop time for the test. This error causes the test to end. This error occurs if the Sleep function does not behave correctly or if a timer does not behave correctly. |