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Events which have been observed by the ETM can be confirmed to have reached the trace bus output with the use of the ATB flush protocol. Both ATB ports must be flushed if all trace is required. The ETM internally flushes instruction and data trace together whenever either flush request is seen but does not guarantee that the trace data has drained from the ETM. When the Cortex®‑R8 processor enters a low-power state, this also causes all trace to be output from the ETM.
If the Cortex‑R8 processor enters a low-power state while an ATB flush request is in progress, the flush is acknowledged only after all instructions presented to the ETM have been traced.