RGB

[D]

Hi

I have a RGB LED and want to have bellow process for brightness:

Red from o to 100 then Green from 0 to 100 and Blue from 0 to 100.

till now i by bellow code i can go for a white color which seems start from 0 to 100. But what i need is different because i am

unable to do it for 3 colors. I will appereciate if u help me. Moreover i am using demo1 of pwm driver example.

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/** @file
 * @defgroup pwm_example_main main.c
 * @{
 * @ingroup pwm_example
 *
 * @brief PWM Example Application main file.
 *
 * This file contains the source code for a sample application using PWM.
 */

#include <stdio.h>
#include <string.h>
#include "nrf_drv_pwm.h"
#include "app_util_platform.h"
#include "app_error.h"
#include "boards.h"
#include "bsp.h"
#include "app_timer.h"
#include "nrf_drv_clock.h"

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#define red 31
#define green 29
#define blue 28

static nrf_drv_pwm_t m_pwm0 = NRF_DRV_PWM_INSTANCE(0);

static uint16_t const              m_demo1_top  = 10000;
static uint16_t const              m_demo1_step = 200;
static uint8_t                     m_demo1_phase;
static nrf_pwm_values_individual_t m_demo1_seq_values;
static nrf_pwm_sequence_t const    m_demo1_seq =
{
    .values.p_individual = &m_demo1_seq_values,
    .length              = NRF_PWM_VALUES_LENGTH(m_demo1_seq_values),
    .repeats             = 0,
    .end_delay           = 0
};

static void demo1_handler(nrf_drv_pwm_evt_type_t event_type)
{
    if (event_type == NRF_DRV_PWM_EVT_FINISHED)
    {
        uint8_t channel    = m_demo1_phase >> 1;
        bool    down       = m_demo1_phase & 1;
        bool    next_phase = false;

        uint16_t * p_channels = (uint16_t *)&m_demo1_seq_values;
        uint16_t value = p_channels[channel];
        if (down)
        {
            value -= m_demo1_step;
            if (value == 0)
            {
                next_phase = true;
            }
        }
        else
        {
            value += m_demo1_step;
            if (value >= m_demo1_top)
            {
                next_phase = true;
            }
        }
        p_channels[channel] = value;

        if (next_phase)
        {
            if (++m_demo1_phase >= 2 * NRF_PWM_CHANNEL_COUNT)
            {
                m_demo1_phase = 0;
            }
        }
    }
}
static void demo1(void)
{

    nrf_drv_pwm_config_t const config0 =
    {
        .output_pins =
        {
        
          red | NRF_DRV_PWM_PIN_INVERTED, // channel 0
          green| NRF_DRV_PWM_PIN_INVERTED, // channel 1
          blue | NRF_DRV_PWM_PIN_INVERTED, // channel 2
        
        },
        .irq_priority = APP_IRQ_PRIORITY_LOWEST,
        .base_clock   = NRF_PWM_CLK_1MHz,
        .count_mode   = NRF_PWM_MODE_UP,
        .top_value    = m_demo1_top,
        .load_mode    = NRF_PWM_LOAD_INDIVIDUAL,
        .step_mode    = NRF_PWM_STEP_AUTO
    };
    APP_ERROR_CHECK(nrf_drv_pwm_init(&m_pwm0, &config0, demo1_handler));

    (void)nrf_drv_pwm_simple_playback(&m_pwm0, &m_demo1_seq, 1,
                                      NRF_DRV_PWM_FLAG_LOOP);
}

int main(void)
{
    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
  
    demo1();

    for (;;)
    {
       
    }
}

[awneil]

D said:

Red from o to 100 then Green from 0 to 100 and Blue from 0 to 100.

and that is exactly what the unmodified demo1 does on an nRF52DK (PCA10040) - except that it has 1 extra  LED::

1. Fade LED1 up, then down
2. Fade LED2 up, then down
3. Fade LED3 up, then down
4. Fade LED4 up, then down
5. repeat from 1.

See: https://devzone.nordicsemi.com/f/nordic-q-a/39361/pwm---demo-1-event-handler/152452#152452

D said:

by bellow code i can go for a white color which seems start from 0 to 100

Note that it's "below" - not "bellow".

If you're seeing "white" fading from 0 to 100%, that means that you have all 3 LEDs fading together - instead of each one in turn.

I suggest that you go back to the unmodified demo1, get that working, then try changing that to do 3 LEDs instead of 4...

[D]

I have seen by the help of oscilloscope and i know demo1 is what i need! that is why i am using demo1! but it is strange for me that when i observe it by oscilloscope, RGB channels fading up and down according to concept. But in reality, we have below process. as you see i tried one channel and i understood that we have a ''on time'' while there is no fading up and down. And that is why we have white color because in on time with 3 colors we have white color! So, it means leds are not fading together as you mentioned.

I will appreciate if you let me know from where this '' on time'' come from?

[awneil]

Sorry - I can't understand that at all.

Do you have the unmodified demo working on a Dev Kit?

[D]

what do u mean? I have the unmodified pwm driver also and tried inside of that also too but im recieving the same result.

[D]

I mean for 3 second led is on and then have fading up and down and again it will repeat.