The TPIU is configured for the largest port size permissible, 32 bits of TRACEDATA, TRACECLK, and TRACECTL.
TRACECLK is always exported to enable synchronization back with the data and so is not optional.
TRACECTL is required unless a new TPA is used that is aware of the formatter protocol which can remove extra packets used to expand data sequences. For Normal and Bypass modes, TRACECTL must be present.
TRACEDATA can be defined as any size up to 32 bits. For backwards compatibility and usage with ETMv3 trace capture devices, a minimum port width of 2 bits is permitted, that is, TRACEDATA[1:0].
Table 8.3 shows some typical Trace Out Port sizes.
|TRACECLK present||TRACECTL present||TRACEDATA width||Total pin count||Comment|
|Yes||Yes||32 bits [31:0]||34||Largest implementation|
|Yes||No||9 bits [8:0]||10||Extra data pin available in comparison to the typical ETM implementation.|
|Yes||Yes||8 bits [7:0]||10||Typical ETM-compatible TPA implementation.|
|Yes||Yes||2 bits [1:0]||4||Smallest implementation with typical TPAs.|
|Yes||No||1 bit ||2||Smallest implementation with a protocol-aware TPA|