I wrote a tutorial on using the nrF52 Development Kit with Keil MDK.
This document features essential debugging capabilities of the nrF52 series.
ETM Instruction Trace: provides program flow debugging including Hard Fault crashes, Code Coverage (.gcov) and Performance Analysis. A Keil ULINKpro or Segger J-Trace is needed.
Serial Wire Viewer (SWV) is data trace. Can view data writes, exceptions and interrupts, counters and more. Up to four variables can be displayed in a graphical format real-time.
A tickless RTOS using Keil RTX example is included. RTX has a BSD or Apache 2.0 license and is free. There are ports for Keil, IAR and GCC. Keil uVision also supports FreeRTOS.
You can use the free evaluation version of MDK - up to 32K code size.
There are many examples for the nrF52 in the Software Packs.
San Jose, California
Thanks for digging into this Bob!