pwm

RE: pwm

inghowe83 — Mon, 24 Dec 2018 06:17:01 GMT

may I know where to change the duty cycle? The documentation is kinda hard to read and understand.

RE: pwm

Fri, 12 Oct 2018 05:20:32 GMT

Thank you awneil. it worked.

RE: pwm

awneil — Wed, 10 Oct 2018 15:51:54 GMT

No.

The "top" value sets the period - it's the duty cycle that you need to vary.

RE: pwm

Wed, 10 Oct 2018 14:27:26 GMT

After put the code instead of the demo3 and decreasing the top_value i expected to observe changing in led brightness. But nothing happened. I want to know know how to change the led intensity brightness.

RE: pwm

awneil — Wed, 10 Oct 2018 14:11:31 GMT

[quote userid="73588" url="~/f/nordic-q-a/39340/pwm/152362"]i saw your post before which it was about set a fixed duty cycle[/quote]

This one: https://devzone.nordicsemi.com/f/nordic-q-a/38607/nrf5-sdk15-0---pwm-driver-just-set-a-fixed-duty-cycle ?

So did you see what I said about setting top_value = 0x8000 ?

RE: pwm

awneil — Wed, 10 Oct 2018 14:07:46 GMT

So what, exactly, happens when you run that code?

And what were you expecting to happen?

And what testing / debugging / investigation have you done to find the problem?

RE: pwm

Wed, 10 Oct 2018 14:00:43 GMT

moreover i put it bellow code instead of demo 3:

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_2MHz,//NRF_PWM_CLK_125kHz,
        .count_mode   = NRF_PWM_MODE_UP,
        .top_value    = 32768, // = 0x8000
        .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[] =
    {
        0x3000,
//        0x2000,
//        0x4000,
//        0x6000,
//        0x7FFF,
//        0x8000
    };
    nrf_pwm_sequence_t const seq =
    {
        .values.p_common = seq_values,
        .length          = NRF_PWM_VALUES_LENGTH(seq_values),
        .repeats         = 0,
        .end_delay       = 0
    };

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

RE: pwm

Wed, 10 Oct 2018 12:55:06 GMT

I mean to say that for example turning an led on with 80 percent brightness or 10 percent or...

RE: pwm

Wed, 10 Oct 2018 12:47:27 GMT

Thank you for replying. i saw your post before which it was about set a fixed duty cycle. i want to turn the led on with different brightness . My main goal is using these different brightness for making different color in one RGB led.

i dont need the led go from 0 to 100 or vice versa. just a constant led brightness.

RE: pwm

awneil — Wed, 10 Oct 2018 12:38:16 GMT

[quote userid="73588" url="~/f/nordic-q-a/39340/pwm"]after changing top_value [/quote]

to what? and how did you change it?