Table 2.1 shows the valid trace packets that the STM generates.
|ASYNC||Alignment||Provides alignment synchronization for the trace stream. This packet is always followed by a VERSION packet.|
Channel indicator. This packet is sent only when the software channel is changed. If any of the upper 8 bits of the channel number change, C16 is sent. C8 is sent if the channel change is limited to any of the lower 8 bits.
The default channel is 0, set when VERSION is generated.
|D4, D8, D16, D32||Data||Data only.|
|D4M, D8M, D16M, D32M||Data||Data with marker.|
|D4TS, D8TS, D16TS, D32TS||Data||Data with timestamp.|
|D4MTS, D8MTS, D16MTS, D32MTS||Data||Data with marker and timestamp.|
Master indicator. This packet is sent only when the source master for the trace is changed.
The default master is 0, set when VERSION is generated.
|MERR||Error||Master Error. Generated when written stimulus is dropped because of a full buffer.|
|GERR||Error||Global Error. Generated when written stimulus from multiple masters is dropped because of a full buffer and MERR cannot be sent for each master.|
|FLAG||Marker||Flag, can be used to indicate message boundaries.|
|FLAG_TS||Marker||Flag with timestamp.|
|NULL||Filler||Filler packet. The STM can insert this to byte align the trace stream for ATB output.|
|TRIG_TS||Trigger||Trigger with timestamp.|
Indicates protocol version. Always sent immediately after ASYNC. Also resets the active master and channel values to 0.
The STM generates the following VERSION values only:
3 = STPv2 with natural binary STPv2 timestamps
4 = STPv2 with Gray coded STPv2 timestamps.
Indicates the frequency of the global system counter supplying timestamp information, in Hertz.
This packet is always sent immediately after an ASYNC-VERSION sequence.
There are a number of STPv2 trace packets that the STM does not generate. See Constraints and limitations of use for details of these trace packets.