This anomaly applies to IC Rev. Engineering A, build codes QFAA-AA0, QFAA-AC0, CGAA-AA0.
When a debug session is started, TracePort pins are automatically enabled. This may conflict with hardware connected to those pins (P0.18, P0.16, P0.15, P0.14 and P0.20).
When a debug session is started.
May conflict with hardware connected to pins P0.18, P0.16, P0.15, P0.14 and P0.20.
CoreDebug->DEMCR &= ~CoreDebug_DEMCR_TRCENA_Msk;
This code is already present in the latest system_nrf52.c file.
The consequence of the workaround is that neither Trace, nor SWO nor Data Watchpoint and Trace are available during debugging.