RTT viewer logging doesn't show device log on custom application.

RE: RTT viewer logging doesn't show device log on custom application.

bini2007 — Wed, 26 Mar 2025 07:33:18 GMT

Hi,

Our custom linker file has a different RAM address and size between DFU bootloader and main application.

After setting RAM address and size of main app. on RTT Viewer, we checked the device logs.

Thanks,

Jaehong Park

RE: RTT viewer logging doesn't show device log on custom application.

Edvin — Tue, 25 Mar 2025 13:37:17 GMT

Hello,

The way that RTT works is by being assigned a partition in the RAM, and it just stores whatever you write to your log into the RAM starting at that address. The RTT Viewer just looks through the RAM for this keyword, and when it finds it, it will start reading the RAM from there during runtime.

When you have two applications running, it will just find the first one, and countinue reading from there. So the absolute simplest way to access the RTT log from the application would be to disable RTT Logging in the bootloader. If that doesn't work, you can look at the map file in your build folder, and look for the location of the application's RTT buffer, and enter this when starting your RTT viewer, either as an address, or a search range.

I wish the RTT Viewer would say somewhere on what address it found the RTT buffer, because then you could just set up a search range after the initial buffer, but unfortunately it doesn't. On top of that, every time you build your application, the buffer location may change, so you need to locate it again. Therefore, I suggest that you disable the RTT Logging in the bootloader, if you don't have any issues with the bootloader at the moment.

Best regards,

Edvin

RE: RTT viewer logging doesn't show device log on custom application.

bini2007 — Sun, 23 Mar 2025 12:24:04 GMT

Sorry,

I'm using legacy SDK, nRF SDK 17.1.x version, nRF52833's custom target and softdevice s113.

We added sdk_config.h file as followings.

In addition, we don't use app_config.h on our project.

devzone.nordicsemi.com/.../6327.sdk_5F00_config.h

The problem of logging is not on DFU bootloader but on our main application.

Please any check points for us to do?

Thanks,

RE: RTT viewer logging doesn't show device log on custom application.

Kazi Afroza Sultana — Fri, 21 Mar 2025 08:17:52 GMT

Hello,

Did you select the correct device from the device list? Are the config files in your custom application contain the following configs?

CONFIG_LOG=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_BACKEND_UART=n
CONFIG_UART_CONSOLE=n
CONFIG_USE_SEGGER_RTT=y
CONFIG_RTT_CONSOLE=y