Starting STM trace data capture

STM tracing uses dictionary-based logging to send messages without redundant strings. This is based on the Zephyr logging API's dictionary feature and is particularly useful for assisted multicore logging.

Complete the following steps:

1. Make sure you have configured your application for tracing.

2. Identify the device's serial port for tracing by listing the connected devices:

   nrfutil device list
   

   Note

   When selecting a serial port for the trace, pick the serial port with the highest serial port number.

3. Use the nrfutil trace stm command to start capturing logs from the device, specifying the database configuration for each domain ID, along with the input serial port and output type.
   Use the following command pattern:

   nrfutil trace stm --database-config <domain_id>:build/<app_name>/zephyr/log_dictionary.json --input-serialport <serial_port> --stdout ascii
   

   In this command, the following parameters are used:

   • <domain_id> is the decimal ID of the domain (core) that the application is running on. When using several domains, use a comma to separate each domain in the list.
     Use the following prefixes to indicate the cores:

     Core	Prefix	ID
     Secure Domain	sec	0x21
     Application core	app	0x22
     Radio core	rad	0x23
     System Controller (SysCtrl)	sys	0x2c
     Fast Lightweight Processor (FLPR)	flpr	0x2d
     Peripheral Processor (PPR)	ppr	0x2e

   • <app_name> is the application name.

   • <serial_port> is the serial port used for output.
   • The output can be either the console (--stdout ascii) or a file (--output-ascii out.txt).

   For example:

   • To capture logs from the Secure Domain and the application core, use the following command:

     nrfutil trace stm --database-config 0x21:build/my_app/zephyr/log_dictionary.json,0x22:build/my_app/zephyr/log_dictionary.json --input-serialport COM10 --stdout ascii
     

   • To capture logs from the Secure Domain, the application core, and the radio core, use the following command:

     nrfutil trace stm --database-config 0x21:build/my_app/zephyr/log_dictionary.json,0x22:build/my_app/zephyr/log_dictionary.json,0x23:build/my_app/zephyr/log_dictionary.json --input-serialport COM10 --stdout ascii
     

   nRF Util starts to capture the log data from the specified serial port and uses the provided dictionary databases to decode the logs into a human-readable format. The tool sends the decoded logs to the specified output (either the console or a file).

4. When done, stop tracing by pressing CTRL-C.

For more information about STM tracing with nRF54H20, see the nRF54H20 logging page in the nRF Connect SDK documentation. For more information about multidomain logging, see also Multi-domain logging using ARM Coresight STM in the Zephyr documentation.