from machine import Pin, PWM
import time
_init()

tones = {
    'c': 262,
    'd': 294,
    'e': 330,
    'f': 349,
    'g': 392,
    'a': 440,
    'b': 494,
    'C': 523
}

speaker = PWM(Pin(15, Pin.OUT))

speaker.duty(512)

speaker.freq(tones['c'])
time.sleep(1)
speaker.freq(tones['f'])
time.sleep(1)
speaker.freq(tones['b'])
time.sleep(1)

speaker.duty(0)