How to control each channel of hardware PWM individually?

Thank you for your attention to my question, I would like to inquire how to control each channel of hardware PWM individually, We have 6 LED lights, each LED has different application scenarios, at some point I only want to control one of them,

I see from the example that nrfx_pwm_simple_playback this interface can be used to enable PWM, but how to enable only one of the channels

0 Jared over 4 years ago

Hi,

Have you seen Demo 3 in the PWM driver example? It would show you how to only use one channel:

static void demo3(void)
{
    NRF_LOG_INFO("Demo 3");

    /*
     * This demo uses only one channel, which is reflected on LED 1.
     * The LED blinks three times (200 ms on, 200 ms off), then it stays off
     * for one second.
     * This scheme is performed three times before the peripheral is stopped.
     */

    nrf_drv_pwm_config_t const config0 =
    {
        .output_pins =
        {
            BSP_LED_0 | NRF_DRV_PWM_PIN_INVERTED, // channel 0
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 1
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 2
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 3
        },
        .irq_priority = APP_IRQ_PRIORITY_LOWEST,
        .base_clock   = NRF_PWM_CLK_125kHz,
        .count_mode   = NRF_PWM_MODE_UP,
        .top_value    = 25000,
        .load_mode    = NRF_PWM_LOAD_COMMON,
        .step_mode    = NRF_PWM_STEP_AUTO
    };
    APP_ERROR_CHECK(nrf_drv_pwm_init(&m_pwm0, &config0, NULL));
    m_used |= USED_PWM(0);

    // This array cannot be allocated on stack (hence "static") and it must
    // be in RAM (hence no "const", though its content is not changed).
    static uint16_t /*const*/ seq_values[] =
    {
        0x8000,
             0,
        0x8000,
             0,
        0x8000,
             0
    };
    nrf_pwm_sequence_t const seq =
    {
        .values.p_common = seq_values,
        .length          = NRF_PWM_VALUES_LENGTH(seq_values),
        .repeats         = 0,
        .end_delay       = 4
    };

    (void)nrf_drv_pwm_simple_playback(&m_pwm0, &seq, 3, NRF_DRV_PWM_FLAG_STOP);
}

regards

Jared