Pin assignment for UART on the nRF54L15DK

[a.da]

Hello.

I am testing UART connectivity using the nRF54L15DK.

After assigning pins to TX and RX, there were combinations that worked fine and combinations that didn't.
There are no build errors. The program starts up successfully, but UART communication doesn't work.
In both cases, there doesn't appear to be any conflict with other pins.
Even after explicitly removing "uart30_default" and "uart30_sleep" where P0.0 and P0.1 are used, the results didn't change.
Since RST and CST are not being used, I haven't assigned them.

The "nrf54l15dk_nrf54l15_cpuapp.overlay" is as follows. Everything is the same except for this file.
Is there any configuration oversight or constraint?

OK

/ {
	chosen {
		nordic,nus-uart = &uart21;
	};
};

&uart21 {
	status = "okay";
	current-speed = <9600>;
	pinctrl-0 = <&uart21_default_alt>;
	pinctrl-1 = <&uart21_sleep_alt>;
	pinctrl-names = "default", "sleep";
	/delete-property/ endtx-stoptx-supported;
	/delete-property/ frame-timeout-supported;
};

&pinctrl {
	uart21_default_alt: uart21_default_alt {
		group1 {
			psels = <NRF_PSEL(UART_TX, 1, 11)>, <NRF_PSEL(UART_RX, 1, 12)>;
		};
	};
	uart21_sleep_alt: uart21_sleep_alt {
		group1 {
			psels = <NRF_PSEL(UART_TX, 1, 11)>, <NRF_PSEL(UART_RX, 1, 12)>;
			low-power-enable;
		};
	};
};

NG

/ {
	chosen {
		nordic,nus-uart = &uart30;
	};
};

&uart30 {
	status = "okay";
	current-speed = <9600>;
	pinctrl-0 = <&uart30_default_alt>;
	pinctrl-1 = <&uart30_sleep_alt>;
	pinctrl-names = "default", "sleep";
	/delete-property/ endtx-stoptx-supported;
	/delete-property/ frame-timeout-supported;
};

&pinctrl {
	/delete-node/ uart30_default;
	/delete-node/ uart30_sleep;
	uart30_default_alt: uart30_default_alt {
		group1 {
			psels = <NRF_PSEL(UART_TX, 0, 0)>, <NRF_PSEL(UART_RX, 0, 1)>;
		};
	};
	uart30_sleep_alt: uart30_sleep_alt {
		group1 {
			psels = <NRF_PSEL(UART_TX, 0, 0)>, <NRF_PSEL(UART_RX, 0, 1)>;
			low-power-enable;
		};
	};
};

Thanks for reading.

a.da

[Simonr]

Hi

I'm not sure I understand the question here I'm afraid. Do you mean that serial port 1 pops up with used pins in the Visual editor while the serial port 0 pins does not? If so, how did you open the Visual editor exactly?

Worth noting as well: One of my colleagues also made this unofficial nRF54L15 Pin Planner that should help users to find available pins for use here: https://hlord2000.github.io/ Please note that it's not official from Nordic, so it's not been verified by our test team and should be used at your own discretion.

Best regards,

Simon

[a.da]

Hi Simon,

I apologize for not being able to explain it clearly.

Simonr said:

Do you mean that serial port 1 pops up with used pins in the Visual editor while the serial port 0 pins does not?

Yes.
I thought that if P0.00-P0.03 are already used by 'Serial Port 0', they would be displayed in the Editor, but am I mistaken?

Simonr said:

If so, how did you open the Visual editor exactly?

I pressed the 'Show Visual Editor' button in my overlay file.
What could be the suspicious point?

Kind regards,

a.da