/*
** Raspberry Pi Pico SDK PWM Example
** Originally from Pico PMW Example, simplified
**  
*/
#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/gpio.h"
#include "hardware/pwm.h"

#define GPIO_LED 3
#define MAX_DUTY_CYCLE 100 // percent

int main() {
  int change = 10;    
  int dutyPercent = 0;
  float clkdiv = 255.0;

  stdio_init_all(); // UART setup for both input and output

  // PWM setup
  gpio_set_function(GPIO_LED, GPIO_FUNC_PWM);
  uint slice_num = pwm_gpio_to_slice_num(GPIO_LED);
  pwm_set_clkdiv(slice_num, clkdiv);
  pwm_set_wrap(slice_num, MAX_DUTY_CYCLE);  
  pwm_set_enabled(slice_num, true);

  while (1) {
    dutyPercent += change;
    if (dutyPercent >= MAX_DUTY_CYCLE) {
      dutyPercent = 0;
    } // when at max, go directly back to zero

    pwm_set_gpio_level(GPIO_LED, dutyPercent);
    printf("LED is now %d\r\n", dutyPercent);
    sleep_ms(200);

  }
}