6.1.6. TD PIPESTAT signals

A pipeline status of TD (Trace Disabled) means that trace FIFO data is not present on the TRACEPKT pins this cycle. There are two possible reasons for this:

There is no data to be traced in the FIFO

If the FIFO is not empty, the status is WT (Wait).

The trace output is a Trace FIFO Offset (TFO), for ETM synchronization

The decompression software must inspect the TRACEPKT value to determine whether the output is a Trace FIFO Offset (TFO). If TRACEPKT[0] is asserted HIGH, TRACEPKT[3:1]is used for TFO outputs, as described in Trace FIFO offsets.

TCDs can discard TD cycles where TRACEPKT[0] = 0. TRACEPKT[0] is used to differentiate between cycle-accurate and non-cycle-accurate tracing. For more information, see Cycle-accurate tracing.

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