subsys/logging/backends/Kconfig.swo

# Copyright (c) 2021 Nordic Semiconductor ASA
# SPDX-License-Identifier: Apache-2.0

config LOG_BACKEND_SWO
	bool "Serial Wire Output (SWO) backend"
	depends on HAS_SWO
	select LOG_OUTPUT
	select LOG_BACKEND_SUPPORTS_FORMAT_TIMESTAMP
	help
	  When enabled, backend will use SWO for logging.

if LOG_BACKEND_SWO

config LOG_BACKEND_SWO_REF_FREQ_HZ
	int "SWO reference clock frequency"
	default $(dt_node_int_prop_int,$(dt_nodelabel_path,itm),swo-ref-frequency) if $(dt_nodelabel_enabled,itm)
	default $(dt_node_int_prop_int,/cpus/cpu@0,clock-frequency) if $(dt_node_has_prop,/cpus/cpu@0,clock-frequency)
	default 0
	help
	  Set SWO reference frequency. In most cases it is equal to CPU
	  frequency.

config LOG_BACKEND_SWO_FREQ_HZ
	int "Set SWO output frequency"
	default 0
	help
	  Set SWO output frequency. Value 0 will select maximum frequency
	  supported by the given MCU. Not all debug probes support high
	  frequency SWO operation. In this case the frequency has to be set
	  manually.

	  SWO value defined by this option will be configured at boot. Most SWO
	  viewer programs will configure SWO frequency when attached to the
	  debug probe. Such configuration will persist only until the device
	  reset. To ensure flawless operation the frequency configured here and
	  by the SWO viewer program has to match.

choice
	prompt "SWO protocol"
	default LOG_BACKEND_SWO_PROTOCOL_NRZ

config LOG_BACKEND_SWO_PROTOCOL_NRZ
	bool "NRZ encoding"
	help
	  Use UART-like NRZ encoding. This is the most common option, but requires the SWO output
	  frequency to be known on the receiving side.

config LOG_BACKEND_SWO_PROTOCOL_MANCHESTER
	bool "Manchester encoding"
	help
	  Use Manchester encoding. This is less widely supported, but permits the clock to be
	  recovered automatically on the receiving side.

endchoice

backend = SWO
backend-str = swo
source "subsys/logging/Kconfig.template.log_format_config"

endif # LOG_BACKEND_SWO