from machine import ADC,Pin
from time import sleep
adc=ADC(Pin(34))
adc.atten(ADC.ATTN_11DB)
# ATTN_0DB --> 1V max 
# ATTN_2_5DB --> 1.34V max
# ATTN_6DB --> 2V max
# ATTN_11DB --> 3.6V max
adc.width(ADC.WIDTH_12BIT)
# ADC.WIDTH_9BIT
# ADC.WIDTH_10BIT
# ADC.WIDTH_11BIT
# ADC.WIDTH_12BIT
while True:
    print (adc.read())