from machine import Pin, ADC

adc = ADC(Pin(4))
adc.atten(ADC.ATTN_11DB)
adc.width(ADC.WIDTH_12BIT)

while True:
  adc_value = adc.read()
  volts = (3.3*adc_value)/4095
  input_voltage = "The input voltage is {:0.2f} volts and raw value is {:4d}."
  print(input_voltage .format(volts, adc_value),end = "\r")