15.3.2. Data and instruction address compare resources

The DWT provides four address comparators on the data bus that provide debug functionality. Within the DWT unit, it is possible to specify the functions triggered by a match, and one of these functions is to generate an ETM match input. These inputs are presented to the ETM as Embedded In Circuit Emulator (ICE) comparator inputs.

A single DWT resource can trigger an ETM event and also generate instrumentation trace directly from the same event.

You can also individually configure the four DWT comparators to compare with the execute PC to permit the ETM access to a PC compare resource. These inputs are presented to the ETM as Embedded ICE comparator inputs.


Using a DWT comparator as a PC comparator reduces the number of available data address comparisons.

See DWT for more information about the DWT unit.

External inputs

Two external inputs, ETMEXTIN[1:0], enable additional on-chip IP to generate trigger/enable signals for the ETM.

Start/stop block

The start/stop block controls start/stop behavior by using the embedded ICE inputs to the ETM. The DWT controls these inputs.

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