5.7.2.2 SAM Serial Wire Output (SWO)

The CoreSight SWO is a trace data drain that acts as a bridge between the on-chip trace data to a data stream that is captured by a Trace Port Analyzer (TPA). It is a TPIU-like device that supports a limited subset of the full TPIU functionality, to minimize gate count for a simple debug solution.

Compared to the TPIU, the SWO contains:

  • no formatter
  • no pattern generator
  • an 8-bit ATB input
  • no synchronous trace output, that is, no TRACEDATA, TRACECTL, or TRACECLK pins
  • no support for flush, because this is not required
  • no support for triggering
  • no external inputs and outputs (EXTCTLIN and EXTCTLOUT are not implemented).
Figure 5-5. SWO Block Diagram