audio_pcm_pico.c

#include <stdio.h>

#include <pico/stdlib.h>
#include "hardware/pwm.h"
#include "hardware/adc.h"

#define LED_PIN_BUILT           25
#define DEFAULT_WRAP_PWM        4096
#define DEFAULT_DIV_PWM         3

void pwm_init_pin(uint8_t pin, uint slice, uint chan, float div) {
    gpio_set_function(pin, GPIO_FUNC_PWM);

    pwm_config config = pwm_get_default_config();
    pwm_config_set_clkdiv(&config, div);
    pwm_config_set_wrap(&config, DEFAULT_WRAP_PWM);

    pwm_init(slice, &config, true);
}

int main() {
    stdio_init_all();
    
    while (!set_sys_clock_khz(270000, true)) {
        printf("Failure config clock");
    }

    adc_init();
    adc_gpio_init(26);
    adc_select_input(0);
    adc_set_clkdiv(1919);


    const uint8_t pwm_0 = 0;
    uint chan_num_0 = pwm_gpio_to_channel(pwm_0);
    uint slice_num_0 = pwm_gpio_to_slice_num(pwm_0);
    pwm_init_pin(pwm_0, slice_num_0, chan_num_0, DEFAULT_DIV_PWM);

    const uint8_t pwm_1 = 1;
    uint chan_num_1 = pwm_gpio_to_channel(pwm_1);
    uint slice_num_1 = pwm_gpio_to_slice_num(pwm_1);
    pwm_init_pin(pwm_1, chan_num_1, slice_num_1, DEFAULT_DIV_PWM);

    while (1) {
        uint16_t signal = adc_read();

        pwm_set_chan_level(slice_num_0, chan_num_0, signal);
        pwm_set_chan_level(slice_num_1, chan_num_1, signal & 0x7ff);
    }
}