11.5.9 Resource selection

The Cortex®‑R8 processor ETM uses event selectors to control trace events (triggers and markers in the trace stream), timestamp events, ViewInst event, ViewData events, Counter controls, and sequencer state transitions.

Each event selector is configured to be sensitive to a resource selector pair, and one resource selector pair can be used to control more than one event selector.

The ETM provides one fixed resource selector pair, with static values of 0 and 1, and seven configurable selector pairs. A resource selector pair provides a bit field OR selector for resources in two different groups, with each group and a configurable boolean combination provided.

The following table shows the resources which can be selected.

Table 11-5 Resource selection

Group Select Resource
0b0000 0-3 External input selector 0-3
0b0010 0-1 Counter at zero 0-1
4-7 Sequencer states 0-3
0b0011 0-1 Single-Shot comparator 0-1
0b0100 0-7 Single address comparator 0-7
0b0101 0-3 Address range comparator 0-3
0b0110 0 Context ID comparator 0

As an example, the following figure shows the steps necessary to use a single address comparator to generate a trigger event and an ATB trigger. This example uses the first single resource selector which can be user-configured.

Figure 11-3 Trigger event resource selection
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