MicroPython knob dimmer on a Raspberry Pi Pico

# MicroPython on a Raspberry Pi Pico: a knob dims an LED.
# The potentiometer's wiper is on GP26 (ADC0), the LED on GP15 is driven by PWM.
from machine import ADC, Pin, PWM
import time

knob = ADC(26)            # read_u16(): 0 at 0 V, 65535 at 3.3 V
led = PWM(Pin(15))
led.freq(1000)            # 1 kHz, far too fast to see it flicker

last = -1
while True:
    value = knob.read_u16()
    led.duty_u16(value)   # the knob's position is the LED's duty cycle
    percent = value * 100 // 65535
    if percent != last:
        print("knob", percent, "%")
        last = percent
    time.sleep_ms(50)