6.1.3. Functional overview

The ATB replicator permits the connection of two trace sinks. If more than two trace sinks are required then multiple replicators can be used.

ID Filtering

If the optional APB interface is implemented, the replicator can filter the trace for each ATB master interface according to the trace ID. Most trace sources use a single trace ID for their trace, and so the replicator can be programmed to control which trace sources are captured by each trace sink.

After reset the replicator behavior matches the behavior of a non-programmable replicator, and no filtering is performed. The filtering settings can be changed at any time.

Trace data flow

As data is received from the trace source, it is passed on to all trace sinks at the same time. The replicator does not accept more data from the trace source until all the trace sinks have accepted this data. This has the impact of reducing the throughput of the replicator to match that of the slowest trace sink.

If the optional APB interface is implemented, a trace sink which supports high bandwidth trace, such as an ETB, can be enabled at the same time as a trace sink which supports only lower bandwidth trace, such as a TPIU. Higher bandwidth trace sources can be filtered out of the trace seen by the TPIU, so that it does not give backpressure to the replicator and therefore impact the trace seen by the ETB.

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