LEDC Fade

[AlexESP32]

Hello guys,

I don't understand the functionality of the LEDC Fade.
I would like to illustrate my problems with following example project. I took the ledc example project and only did few adjustments and then the LEDs do something garbage:

I changed the GPIO Pins to PIN 18,19,23,33 and changed the while loop. All the other stuff stay the same.

The while loop is the following:

Code: Select all

    while (1) {
        printf("1. LEDC fade up to duty = %d\n", LEDC_TEST_DUTY);
        for (ch = 0; ch < LEDC_TEST_CH_NUM; ch++) {
            ledc_set_fade_with_time(ledc_channel[ch].speed_mode,
                    ledc_channel[ch].channel, LEDC_TEST_DUTY, LEDC_TEST_FADE_TIME);
            ledc_fade_start(ledc_channel[ch].speed_mode,
                    ledc_channel[ch].channel, LEDC_FADE_NO_WAIT);
        }
// 1. adjustment: comment out the vTaskDelay
        //vTaskDelay(LEDC_TEST_FADE_TIME / portTICK_PERIOD_MS);

        printf("2. LEDC fade down to duty = 0\n");
        for (ch = 0; ch < LEDC_TEST_CH_NUM; ch++) {
            ledc_set_fade_with_time(ledc_channel[ch].speed_mode,
                    ledc_channel[ch].channel, 0, LEDC_TEST_FADE_TIME);
            ledc_fade_start(ledc_channel[ch].speed_mode,
                    ledc_channel[ch].channel, LEDC_FADE_NO_WAIT);
        }
        vTaskDelay(LEDC_TEST_FADE_TIME / portTICK_PERIOD_MS);

        printf("3. LEDC set duty = %d without fade\n", LEDC_TEST_DUTY);
        for (ch = 0; ch < LEDC_TEST_CH_NUM; ch++) {
            ledc_set_duty(ledc_channel[ch].speed_mode, ledc_channel[ch].channel, LEDC_TEST_DUTY);
            ledc_update_duty(ledc_channel[ch].speed_mode, ledc_channel[ch].channel);
        }
        vTaskDelay(1000 / portTICK_PERIOD_MS);
// 2. adjustment: comment out the following for loop
/*		
        printf("4. LEDC set duty = 0 without fade\n");
        for (ch = 0; ch < LEDC_TEST_CH_NUM; ch++) {
            ledc_set_duty(ledc_channel[ch].speed_mode, ledc_channel[ch].channel, 0);
            ledc_update_duty(ledc_channel[ch].speed_mode, ledc_channel[ch].channel);
        }
        vTaskDelay(1000 / portTICK_PERIOD_MS);*/
    }

So as you can see I only comment out a few lines.
The result looks like:

Code: Select all

I (311) cpu_start: Starting scheduler on PRO CPU.
I (0) cpu_start: Starting scheduler on APP CPU.
1. LEDC fade up to duty = 4000
2. LEDC fade down to duty = 0
W (337) ledc: LEDC FADE TOO SLOW
W (337) ledc: LEDC FADE TOO SLOW
3. LEDC set duty = 4000 without fade
1. LEDC fade up to duty = 4000
2. LEDC fade down to duty = 0
W (4337) ledc: LEDC FADE TOO SLOW
3. LEDC set duty = 4000 without fade
1. LEDC fade up to duty = 4000
2. LEDC fade down to duty = 0
3. LEDC set duty = 4000 without fade

Now 1 LED is always on and the other 3 are fading. Why there is 1 LED always on an why there is the warning message "ledc: LEDC FADE TOO SLOW"?

Thank you

[AlexESP32]

Hey,

This question is still there...

Is the answer too trivial then please let me know Because I dispair with this issue...

Thank you.

[FlorianR]

Hi There,
did you find an Answer? I have the same issue...