Where can I see NRF_LOG output?

[gary]

I am using nrf51 SDK v.12.1. And I found NRF_LOG_INFO("BLINKY START\n"); where can I find this log? Is this different from SEEGER_WriteString or something?

[FormerMember]

The output from NRF_LOG_xxx can be displayed in a terminal (if logging over UART) or in the J-link RTT viewer (logging over RTT).

The sdk_config.h file --> configuration wizard can be used to choose logging over UART or RTT.

As you can see in nrf_log_backend_serial.c, logging over RTT uses SEGGER_RTT_xxx functions.

Update: Use the configuration wizard tab in sdk_config.h to enable RTT and/or UART logging:

[gary]

Thank u~ :^)

[gary]

Im sorry but I have one more question. If I want to use RTT for debugging, how can configure sdk_config.h. And when I use RTT viewer, it doensn't show the result dynamically (for example, printing some string every second). Does RTT viewer work only when the program is loaded on the board?

[FormerMember]

The updated answer shows how to configure the sdk_config.h file to use the logging module. The RTT viewer should update real time, not only when the firmware is loaded..

[gary]

I tried as you said, but it says error : ._build\nrf51422_xxac.axf: error: L6050U: The code size of this image (33560 bytes) exceeds the maximum allowed for this version of the linker. What is this problem?

[FormerMember]

Which example are you testing, ble_app_blinky? Do you use nRF51 or nrf52?

There is a bug with the nrf_log module that is uses too much ram. This post reports the bug and a proposed fix.