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Chapter 6: Solving Problems
If you see exclamation marks "!" in count columns of the trace lists
show cycles feature by setting the two least-significant bits in the third byte of
register SIM_MCR to "11".
If you see exclamation marks "!" in count
columns of the trace lists
This is a normal condition. It indicates the counter overflowed (began again at 0)
before the present state was captured. The exclamation mark warns you that the
counter value may not be accurate because the analyzer is unable to determine how
many times the counter overflowed between the preceding state and the state where
the exclamation mark is shown.
If you were to scroll through a trace list of the entire trace memory in relative count
mode, a "!" would be seen beside the first state after each occurrence of counter
overflow (each 22.9 minutes). If you were to scroll through the entire trace
memory in absolute count, the "!" would be seen beside every state after the first
occurrence of counter overflow.
If you see negative time or state counts in trace
lists
If counter overflow occurs during a trace measurement, you may see a count of
negative time or negative states in trace lists using the absolute time count mode.
This indicates that the counter value stored with the trigger state was greater than
the counter value stored with the present state. In absolute time counts, negative
times will continue to be seen until a state is captured whose counter value is
greater than the trigger state counter value. In relative time counts, the counter
value is corrected so no negative time is seen.
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