A quick note: I finally got around to updating mbed-memory-status to support outputting data using the Serial Wire Output port on a Nordic nRF52 Development Kit.
The trick to getting it work was, as usual with Nordic stuff, a compiler #define (-DENABLE_SWO to be exact). Took a bit of digging to figure this one out and get it working.
This actually lead to some further investigation and the interesting discovery that SWO could possibly offer an extra output-only serial port on most Cortex-M3-and-up chips. But, there are still some blockers on getting that thought working and I haven’t had the time to clear them.