nRF54L15 with SW PWM

[Ivenhor]

Hello Nordic team,

I'm developing firmware for a custom board based on the nRF54L15, where the LEDs are connected to GPIOs on port 2. These pins do not support hardware PWM, so I want to use the nordic,nrf-sw-pwm driver to enable PWM functionality in software.

I based my setup on the nRF54L15DK and PWM LED sample and added the following overlay:

/ {
    sw_pwm: pwm_sw {
        status = "okay";
        compatible = "nordic,nrf-sw-pwm";
        channel-gpios = <&gpio2 8 GPIO_ACTIVE_HIGH>;
        clock-prescaler = <0>;
        generator = <&timer00>;
        #pwm-cells = <3>;
    };

    pwm_leds {
        compatible = "pwm-leds";
        status = "okay";

        red_pwm_led: led_0 {
            pwms = <&sw_pwm 0 PWM_MSEC(20) PWM_POLARITY_NORMAL>;
            label = "Red PWM LED";
        };
    };
};

&timer00 {
    status = "okay";
};

My prj.conf

CONFIG_LOG=y
CONFIG_LOG_MODE_IMMEDIATE=y

CONFIG_PWM=y
CONFIG_PWM_NRF_SW=y
CONFIG_LED=y

However, the build fails with the following error:

nrfx_gpiote.h:75:33: error: 'NRF_GPIOTEDT_N_S_soc_S_peripheral_50000000_S_gpio_50400_P_gpiote_instance_IDX_0_PH_P_instance' undeclared here (not in a function)

It seems that the macro NRF_GPIOTEDT_* is not properly generated.

Questions:

1. Is nordic,nrf-sw-pwm supported on the nRF54L15?

2. What is the correct way to enable and use the nrf-sw-pwm driver with GPIO port 2 on this platform?

3. Are there any limitations or required configurations for using GPIOTE or TIMER with nrf-sw-pwm on nRF54L15?

4. Could you recommend the proper way to integrate and configure this driver in the project?

SDK version 2.9.0
I also tried using SDK version 3.0.0. It also has this error, but besides it there is also an error related to RTC

Thank you in advance!

Best regards,
Oleksandr

[Håkon Alseth]

Hi,

 

SW-PWM is currently not supported for the nRF54L-series devices. For more info, please see this thread:

 pwm_nrf_sw on the 54l15 

 

LEDs are connected to GPIOs on port 2

Software PWM will not be possible on P2 for the nRF54L15, because P2 does not have any GPIOTE capabilities. Please see the port capabilities in the datasheet for more info:

https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/gpio.html#ariaid-title4

 

Kind regards,

Håkon

[Ivenhor]

Thank you.