how to change nrf54l15dk console from uart20 to uart21?

RE: how to change nrf54l15dk console from uart20 to uart21?

casey shen — Wed, 26 Nov 2025 07:51:14 GMT

Hi，odin,

Thank you for help;

P1 is general GPIO for UARTE20-23, and UARTE20 still have special function GPIO for P2.07/P2.08, it can see from datasheet .

RE: how to change nrf54l15dk console from uart20 to uart21?

odin huang — Tue, 25 Nov 2025 03:52:32 GMT

Hi,

You must see it. P2 use UARTE00,

The UARTE 20-23 instances currently seem to be restricted to use on P1.

devzone.nordicsemi.com/.../essential-pin-planning-guidelines-for-the-nrf54l-series

RE: how to change nrf54l15dk console from uart20 to uart21?

casey shen — Mon, 17 Nov 2025 06:42:57 GMT

thanks for helping,

this problem I decide to leave it in future to solve,

now I use transmit string to instead data buff. let mcu to parsing string data;

RE: how to change nrf54l15dk console from uart20 to uart21?

Vidar Berg — Fri, 14 Nov 2025 10:58:05 GMT

[quote userid="148643" url="~/f/nordic-q-a/125520/how-to-change-nrf54l15dk-console-from-uart20-to-uart21/554371"]it just suddely don't work;stop suddenly,don't print error;[/quote]

Unfortunately that does not say much. Here's what I see when I run your project here:

And here's the hex file from that build:

devzone.nordicsemi.com/.../5483.merged.hex

Also, I see you have a duplicate private ticket going in parallel to this. Please avoid creating duplicate tickets.

RE: how to change nrf54l15dk console from uart20 to uart21?

casey shen — Fri, 14 Nov 2025 10:51:03 GMT

hi,if I use P1 gpio,I don't have all those problem;but my board is GPIO2;

RE: how to change nrf54l15dk console from uart20 to uart21?

casey shen — Fri, 14 Nov 2025 10:50:05 GMT

it just suddely don't work;stop suddenly,don't print error;

CONFIG_LOG=y

CONFIG_LOG_DEFAULT_LEVEL=2

CONFIG_SERIAL=y

CONFIG_UART_ASYNC_API=y

that's my error log level;

at first,this problem occur at first time when I open "CONFIG_SERIAL=y CONFIG_UART_ASYNC_API=y"

RE: how to change nrf54l15dk console from uart20 to uart21?

Vidar Berg — Fri, 14 Nov 2025 10:38:26 GMT

Hi,

What happens specifically when you remove this line? Do you get a build error?

RE: how to change nrf54l15dk console from uart20 to uart21?

casey shen — Fri, 14 Nov 2025 10:22:08 GMT

hi,Vidar,

If I don't add that in my code,the 54l05 will carck,dont'work;I don't know why;

RE: how to change nrf54l15dk console from uart20 to uart21?

Vidar Berg — Fri, 14 Nov 2025 09:02:41 GMT

I noticed now that you also had changed the "default-gpio-port" property in your overlay to Port 2. This will prevent the proper cross domain handling in the driver. Please remove the default-gpio-port = <&gpio2>; line in your overlay.

RE: how to change nrf54l15dk console from uart20 to uart21?

casey shen — Fri, 14 Nov 2025 08:09:45 GMT

Hi,Vidar，thanks for reply；

I fix it,still have wrong data come;

I use a periphral board to connect to pc;

RE: how to change nrf54l15dk console from uart20 to uart21?

Vidar Berg — Fri, 14 Nov 2025 07:42:24 GMT

Hi,

Thanks. The only issue I see is that the UART RX pin assignment overlaps with led2:

You can fix this by disabling the led2 node in your devictree overlay:

&led2 {
    status = "disabled";
};

[quote user="casey shen"]the question is the message I send from uart21 to pc ,will have mistake or lost;[/quote]

How are you connecting P2.7 abd P2.8 to your PC?

RE: how to change nrf54l15dk console from uart20 to uart21?

casey shen — Thu, 13 Nov 2025 09:18:46 GMT

hi,

sure,this is my minimal project, can repeat the problem,thank you for your help.

the purpose I want to use uart21 p2.07/2.08 to send message to mcu;

the question is the message I send from uart21 to pc ,will have mistake or lost;

thank you for your help.
devzone.nordicsemi.com/.../l5_5F00_e1_5F00_sol.zip

RE: how to change nrf54l15dk console from uart20 to uart21?

Vidar Berg — Tue, 11 Nov 2025 09:06:44 GMT

Hi,

Do you have logging enabled (over UART or RTT), and if so, are there any errors or warnings logged? I can also debug this on my end if you are able to upload a minimal version of your project here.

RE: how to change nrf54l15dk console from uart20 to uart21?

casey shen — Tue, 11 Nov 2025 06:49:04 GMT

Hi,Vidar,

After I open the macro as you recommended,

My uart21 now can works some seconds,and then it will still let the nrf54l15dk death,the chips doesn't work ntill reset it;

Do you know how to solve this problem?

Thank you for your help.

//it's I add in prj.conf
CONFIG_NRFX_POWER=y
CONFIG_NRF_SYS_EVENT=y
CONFIG_ASSERT=y

//it's I think may take use,I dont know how to open and use those macro, still tring to use;
# CONFIG_UART_21_NRF_HW_ASYNC=y
# CONFIG_UART_21_NRF_HW_ASYNC_TIMER=22
# CONFIG_NRFX_TIMER22=y

RE: how to change nrf54l15dk console from uart20 to uart21?

Vidar Berg — Mon, 10 Nov 2025 16:05:21 GMT

Hello,

The driver will now request and release its request for constant latency mode automatically, but to use this feature you must add CONFIG_NRF_SYS_EVENT=y to your project configuration file (prj.conf). There is an assert to catch this problem at build time, but you need to have ASSERTs enabled for that (CONFIG_ASSERT=y).

Relevant commit: https://github.com/nrfconnect/sdk-zephyr/commit/20db3ee4cf31537296f92c68cea67cb7707c8f3d

Best regards,

Vidar