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This section describes the functionality of the ETM trace unit.
The following figure shows the main functional blocks of the ETM trace unit.
You can limit the amount of trace data generated by the ETM through the process of filtering.
For example, generating trace only in a certain address range. More complicated logic analyzer style filtering options are also available.
The ETM trace unit can also generate a trigger that is a signal to the trace capture device to stop capturing trace.
The trace generated by the ETM trace unit is in a highly-compressed form.
The FIFO enables trace bursts to be flattened out. When the FIFO becomes full, the FIFO signals an overflow. The trace generation logic does not generate any new trace until the FIFO is emptied. This causes a gap in the trace when viewed in the debugger.