How to make ESP32 output 20MHZ's clock

[roctwo]

Hi!
How to make ESP32 output 20MHZ's clock? And can you provide code?

[kolban]

Do you mean you want a square wave output on a GPIO pin that has a frequency of 20MHz? If so, you can likely use the PWM functions.

[roctwo]

OK ,Thank you,sorry for my bad English.I will check it

[ppisljar]

seems pwm can only be used to generate 333k clock ... what about higher frequencies ?

[krzychb]

How to make ESP32 output 20MHZ's clock? And can you provide code?

Below is an example how to generate 20MHz square wave at 50% duty on GPIO18.

Code: Untitled.c Select all

#include "driver/ledc.h"



ledc_timer_config_t ledc_timer = {

    .speed_mode = LEDC_HIGH_SPEED_MODE,

    .timer_num  = LEDC_TIMER_0,

    .bit_num    = 2,

    .freq_hz    = 20000000

};



ledc_channel_config_t ledc_channel = {

    .channel    = LEDC_CHANNEL_0,

    .gpio_num   = 18,

    .speed_mode = LEDC_HIGH_SPEED_MODE,

    .timer_sel  = LEDC_TIMER_0,

    .duty       = 2

};



void app_main()

{

    ledc_timer_config(&ledc_timer);

    ledc_channel_config(&ledc_channel);

    while (1) {

        ;

    }

}

The LED PWM Controller can generate up to 40MHz square wave.