text: import time
  from machine import PWM, Pin
  
  def pulse():
      for i in range(0, 101):
          p = PWM(0, Pin("A17", mode=Pin.OUT), freq=PWM.FREQ_16MHZ, duty=i, period=16000)
          p.init()
          time.sleep_ms(10)
          p.deinit()
  
      for i in range(0, 101):
          p = PWM(0, Pin("A17", mode=Pin.OUT), freq=PWM.FREQ_16MHZ, duty=100-i, period=16000)
          p.init()
          time.sleep_ms(10)
          p.deinit()
  