nRF54H20 domains include ARM Coresight System Trace Macrocell (STM) hardware, which collects trace data from multiple domains using standalone or assisted multicore logging. The Embedded Trace Router (ETR) is a hardware feature that provides a circular buffer in RAM for trace data.
To show the logs for a given nRF54H20 domain in the UART output, you must enable the STM for both the application core (as the ETR buffer processing proxy) and that domain's CPU. To do so, use the Nordic Standalone STM logging snippet (nordic-log-stm-dict) when building the application for the related cores. For example, the following command uses the snippet when building for the application core:
west build -b nrf54h20dk/nrf54h20/cpuapp -S nordic-log-stm-dict
All cores must use the same logging configuration.
Note
The nordic-log-stm-dict snippet uses dictionary-based STM logging on the device.
Use nrfutil trace stm with the matching log_dictionary.json from your build to decode that stream to human-readable text on standard output.
See trace stm for capture and output options.
After building your application, the build directories for each core (build/<app_name>/zephyr/, where <app_name> is the application name for each core) will contain a dictionary database file named log_dictionary.json. This file is crucial for decoding the logs and updates with every build.