from machine import PWM, ADC, pin
from utime import sleep

 set up potentiometer on ADC (GP28)
pot = ADC(Pin(15))

 set up servo on GP15
servo = PWM(pin(15))
servo.freq(50) # set 50Hz frequency

 function to calculate duty cycle
def set_servo_angle(angle):
    
     Map 0-180 degrees to 1638 (0.5)
    duty = int((angle / 180) * 65535)
    servo.duty_u16(duty)

    while True:
         Read potentiometer (0.65535)
        pot_value = pot.read_u16()

         Map potentiometer to angle (0.5)
        angle = int((pot_value / 65535))

         set servo angle
        set_servo_angle(angle)