RE: Using UART1 in Non-Secure Mode on nRF9151 DK with TF-M Enabled

FedericaMayorga — Thu, 05 Feb 2026 15:20:16 GMT

Hi Vidar,

Thanks for the clarification.

We tested again with TF-M enabled and CONFIG_TFM_LOG_LEVEL_SILENCE=y, and UART1 is indeed available to the non-secure application as expected.

The issue turned out not to be related to TF-M or UART reservation, but rather to a host-side serial terminal problem: on macOS, minicom was not showing the UART output correctly. When testing on Ubuntu, UART1 worked fine.

So the configuration was correct.

Thanks again for your help!

Best regards,

Federica from OWL Services.

RE: Using UART1 in Non-Secure Mode on nRF9151 DK with TF-M Enabled

Vidar Berg — Tue, 03 Feb 2026 12:50:57 GMT

Hello,

UART1 should be available to the application as long as CONFIG_TFM_LOG_LEVEL_SILENCE is selected which I see you have done already in your project configuration file.

VCOM1 must be disabled in the board configurator app to change the routing of the UART pins from the Jlink MCU to the pin headers. Had you tested the same without TF-M and verified that it worked?

Best regards,

Vidar