7.10.2. NonPeriodic synchronization

When the Programming bit is cleared or the OS Lock is cleared, the ETM must generate the A-sync and I-sync packets before generating any other trace. It does this by performing the following sequence:

  1. The ETM first generates an A-sync packet.

  2. Next the ETM generates a nonperiodic I-sync packet. This is generated when trace is turned on, unless a trigger occurs before trace is turned on.

  3. If data tracing is enabled, the ETM generates a D-Sync packet on the next data packet.

In ETMv3.5, if Timestamping is enabled, a T-Sync packet must be generated after stage 2. The T-Sync packet might not be output immediately after the I-Sync packet.

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