nrf54l15 UART00 GPIO2 Not Working

I am currently working with the nrf54l15, I have both the DK and a custom board I designed. I am running into issues with the uart00 peripheral when using custom GPIO pins on Port P2. I have connected the DK up to a logic analyser and I confirmed that when connected to the dedicated uart pins 2.7 and 2.8, everything works as expected. However, when using other pins on port P2 such as 2.4 and 2.5, I cannot get the peripheral to work correctly. Note that I have disabled the flash memory which is connected to spi00 for when testing pins 2.4 and 2.5. I have also tested other pins on Port 2 and haven't been able to replicate the working result with the logic analyser.

The only section of my project that I am modifying is the device tree configuration for the uart controller -

uart00_default: uart00_default {
		group1 {
			psels = <NRF_PSEL(UART_TX, 2, 4)>; // If you set this to 2, 8 it works
		};
		group2 {
			psels = <NRF_PSEL(UART_RX, 2, 5)>; // If you set this to 2, 7 it works
			bias-pull-up;
		};
	};
	
	uart00_sleep: uart00_sleep {
		group1 {
			psels = <NRF_PSEL(UART_TX, 2, 4)>, // If you set this to 2, 8 it works
				<NRF_PSEL(UART_RX, 2, 5)>; // If you set this to 2, 7 it works
			low-power-enable;
		};
	};
	
	&uart00 {
    	status = "okay";
    	current-speed = <115200>;
    	pinctrl-0 = <&uart00_default>;
    	pinctrl-1 = <&uart00_sleep>;
    	pinctrl-names = "default", "sleep";
    };

I am a quite confused why this is happening since the data sheet states that you can use GPIO on P2 for uarte00. 

Have I missed something somewhere?

I am currently using the ncs v2.9.0-nRF54H20-rc1 SDK + toolchain on MacOS 15.2.

  • Hi,

    Peripherals on P2 can only be used on the dedicated pins.

    UARTE00 can only use P2.00/P2.07 for RX, P2.02/P2.078 for TX, P2.04/P2.09 for CTS and P2.05/P2.10 for RTS.

    See the pin assignments section for a overview of all the dedicated pins on P2.

     

    I am currently using the ncs v2.9.0-nRF54H20-rc1 SDK + toolchain on MacOS 15.2.

    Since you aren't using the nRF54H20 you should instead be using NCS version v2.9.0, and not the nRF54H20 specific SDK version.

    Best regards,

    Bendik

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