PWM-LED Configuration

RE: PWM-LED Configuration

Nishant Gaurav — Sat, 02 May 2026 08:56:36 GMT

Hi vinay

Sorry for late response

yes it is possible to configure LED as an PWM output channel as LED2 is connected to the nRF5340 SoC and the pins are ;

P0.14	Red
P0.26	Green
P0.15	Blue

here is the code base for this https://github.com/NordicDeveloperAcademy/ncs-inter/tree/main/l4/l4_e1_sol , i hope this will help

RE: PWM-LED Configuration

VinayKotadamakki — Sat, 02 May 2026 07:50:07 GMT

Hi Nishant,

Is it possible to configure LED as an PWM output channel for Thingy 91x/nrf5340 SoC?

Thanks and regards,

Vinay

RE: PWM-LED Configuration

VinayKotadamakki — Mon, 27 Apr 2026 05:41:18 GMT

Hi Nishant,

I am able to build it without any errors. Thanks for that.

But when I probe Trace0 pin in current measurement and debug board connector. But I cant see any pwm output. Will you please let me know what else I can probe to get pwm channel output. Or am I missing something here?

Thanks and regards,

Vinay

RE: PWM-LED Configuration

Nishant Gaurav — Fri, 24 Apr 2026 06:40:05 GMT

in thingy91x_nrf9151_ns.overlay contains something like:

&exp_board_enable {
...
};

remove this reference and try again

RE: PWM-LED Configuration

VinayKotadamakki — Fri, 24 Apr 2026 06:31:26 GMT

Hi Nishant,

Thank you for the quick responses. I really appreciate it.

I have added thingy91x_nrf9151_ns.overlay to extra devicetree overlays in build configuration. But I am facing some issues while building the configuration once I add this overlay.

Adding log file for better understanding.

devzone.nordicsemi.com/.../Thingy91x_5F00_nrf5430_5F00_pwm_5F00_build_5F00_logs_5F00_24_5F00_04_5F00_2026.txt

Thanks and regards,

Vinay

RE: PWM-LED Configuration

Nishant Gaurav — Fri, 24 Apr 2026 06:10:33 GMT

hi vinay,

yes add thingy91x_nrf9151_ns.overlay to extra devicetree overlays in build configuration, and go through schematic to get that pin,

thanks and regards

Nishant

RE: PWM-LED Configuration

VinayKotadamakki — Fri, 24 Apr 2026 05:43:56 GMT

Hi Nishant,

We have to add thingy91x_nrf9151_ns.overlay to extra devicetree overlays in build configuration right?

Thanks and regards,

Vinay

RE: PWM-LED Configuration

Nishant Gaurav — Thu, 23 Apr 2026 09:33:22 GMT

The current measurement and debug board connector (P9) on the Thingy:91 X exposes the nRF9151 SiP's TRACE pins, which are connected to nRF5340 GPIO pins P0.30–P1.01 (TRACE0–TRACE3 and CLK). These are physically accessible on the P9 connector.

however i suggest you to Review PCA20065_Schematic_And_PCB.pdf (available in the Thingy:91 X hardware files) to identify if there is an accessible pad or trace near P0.30 on the PCB.

last option will be to tap MCU leg to probe the line.

RE: PWM-LED Configuration

VinayKotadamakki — Thu, 23 Apr 2026 09:22:33 GMT

Hi Nishant,

Yes I know. But is there any test points or pins available in Thingy 91x nRF5340 pcb. Or we have to tap MCU leg to probe the line.?

Thanks and regards,

vinay

RE: PWM-LED Configuration

Nishant Gaurav — Thu, 23 Apr 2026 09:16:34 GMT

To confirm the PWM signal on P0.30, you would typically use an oscilloscope or logic analyzer connected to that pin on your board.

i suggest you to go through in-depth guidance on PWM configuration and testing, the Nordic Developer Academy course on nRF Connect SDK Intermediate (Lesson 4). [PWM exercise]

RE: PWM-LED Configuration

VinayKotadamakki — Thu, 23 Apr 2026 09:03:22 GMT

Hi Nishant,

Thank you for your response.

Now I am able to build and flash pwm binary after the modification mentioned by you.

But how I can check PWM Signal, as we have configured pwm0 channel to P0.30 how we can check the output channel of PWM output.

Thanks and regards,

Vinay

RE: PWM-LED Configuration

Nishant Gaurav — Thu, 23 Apr 2026 06:31:31 GMT

Your overlay is trying to use a pwm_led0 (or similar) alias that doesn't exist for the thingy91x/nrf5340/cpuapp board. This is similar to a known issue where a sample or application expects a specific DeviceTree node that the target board doesn't provide

1 :Follow to fix this

Define the alias in your overlay file. In your thingy91x_nrf5340_cpuapp.overlay, you need to properly define the led_pwm_0 node and add it under /aliases.

/ {
aliases {
led-pwm-0 = &pwm_led0;
};

pwmleds {
compatible = "pwm-leds";
pwm_led0: pwm_led_0 {
pwms = <&pwm0 0 PWM_MSEC(20) PWM_POLARITY_NORMAL>;
};
};
};

Adjust the PWM instance, channel, and period to match your hardware.

Ensure the PWM peripheral is enabled in your prj.conf:
CONFIG_PWM=y
CONFIG_PWM_NRFX=y

RE: PWM-LED Configuration

VinayKotadamakki — Thu, 23 Apr 2026 06:08:17 GMT

Hello Nishant,

Thank you for your reply. I really appreciate it.

But I am facing issue while building this configuration.

I am adding the logs and the project zip file which I have configured as per your guidance.

devzone.nordicsemi.com/.../Thingy91x_5F00_nrf5430_5F00_pwm.zip devzone.nordicsemi.com/.../Thingy91x_5F00_nrf5430_5F00_pwm_5F00_build_5F00_logs.txt

Thanks and regards,

Vinay

RE: PWM-LED Configuration

Nishant Gaurav — Wed, 22 Apr 2026 17:56:29 GMT

Yes, PWM can be configured for the nRF5340 on the Thingy:91 X

Step 1 :- PWM in prj.conf

CONFIG_PWM=y
CONFIG_PWM_LOG_LEVEL_DBG=y
CONFIG_LED=y
CONFIG_LED_PWM=y

Step 2 :- Pin Control & PWM in Devicetree Overlay

&pinctrl {
    pwm0_default_alt: pwm0_default_alt {
        group1 {
            psels = <NRF_PSEL(PWM_OUT0, 0, 30)>;
        };
    };

    pwm0_sleep_alt: pwm0_sleep_alt {
        group1 {
            psels = <NRF_PSEL(PWM_OUT0, 0, 30)>;
            low-power-enable;
        };
    };
};

&pwm0 {
    status = "okay";
    pinctrl-0 = <&pwm0_default_alt>;
    pinctrl-1 = <&pwm0_sleep_alt>;
    pinctrl-names = "default", "sleep";
};

/ {
    pwmleds {
        compatible = "pwm-leds";
        led_pwm_0 {
            pwms = <&pwm0 0 PWM_MSEC(20) PWM_POLARITY_NORMAL>;
            label = "PWM LED 0";
        };
    };

    aliases {
        pwm-led0 = &led_pwm_0;
    };
};


Step 3 :- application code

#include <zephyr/device.h>
#include <zephyr/drivers/pwm.h>

#define PWM_PERIOD_NS   20000000
#define PWM_PULSE_WIDTH 1400000

static const struct pwm_dt_spec pwm_led0 =
    PWM_DT_SPEC_GET(DT_ALIAS(pwm_led0));

int main(void) {
    if (!pwm_is_ready_dt(&pwm_led0)) {
        return 0;
    }
    pwm_set_dt(&pwm_led0, PWM_PERIOD_NS, PWM_PULSE_WIDTH);
    return 0;
}



Step 4 :- thingy91x_nrf9151_ns.overlay (external power fix)

&exp_board_enable {
  /delete-property/ output-low;
  output-high;
};

Build with west build -b thingy91x/nrf5340/cpuapp and flash. Let me know if you hit any issues!